CN108682464B

CN108682464B - Method for expanding spent fuel pool of million-kilowatt nuclear power plant

Info

Publication number: CN108682464B
Application number: CN201810493565.6A
Authority: CN
Inventors: 谭世杰; 刘省勇; 陈军; 张士朋; 张文利; 林杰东; 陈军琦; 李俊; 郭振武; 孙新峰; 李琪; 陈秋炀; 肖伟; 秦强; 袁亮
Original assignee: China General Nuclear Power Corp; CGN Power Co Ltd; Daya Bay Nuclear Power Operations and Management Co Ltd; Guangdong Nuclear Power Joint Venture Co Ltd; Suzhou Nuclear Power Research Institute Co Ltd
Current assignee: China General Nuclear Power Corp; CGN Power Co Ltd; Nuclear Power Institute of China; Daya Bay Nuclear Power Operations and Management Co Ltd; Guangdong Nuclear Power Joint Venture Co Ltd; Suzhou Nuclear Power Research Institute Co Ltd; Shenzhen China Guangdong Nuclear Engineering Design Co Ltd
Priority date: 2018-05-22
Filing date: 2018-05-22
Publication date: 2020-04-24
Anticipated expiration: 2038-05-22
Also published as: CN108682464A

Abstract

The invention belongs to the technical field of nuclear auxiliary cooling water of a million kilowatt nuclear power station, and discloses a spent fuel pool capacity expansion method of a million kilowatt nuclear power station. The capacity expansion method comprises the following steps: dismantling an old framework: the method comprises the following steps of (1) hoisting an old framework placed in a spent fuel pool by using a first hoisting device, and transporting the framework to a designated area by using transport equipment for storage; leveling a high-density framework, and leveling the high-density framework through a leveling device to adapt to the height of the bottom of the spent fuel pool; and (3) high-density grid mounting: placing the high-density grillwork at the position of an old grillwork in the spent fuel pool by using a second hoisting device; moving and mounting the spent fuel: and moving the spent fuel to the high-density lattice for storage. The capacity expansion method provided by the invention solves the problem that the storage requirement of the spent fuel in the nuclear power station cannot be met due to the full capacity of the spent fuel pool, and provides possibility for continuously storing the spent fuel subsequently.

Description

Method for expanding spent fuel pool of million-kilowatt nuclear power plant

Technical Field

The invention belongs to the technical field of nuclear auxiliary cooling water of a million-kilowatt nuclear power station, and particularly relates to a spent fuel pool capacity expansion method of a million-kilowatt nuclear power plant.

Background

Spent fuel is a nuclear fuel that has been irradiated with radiation and used, and is produced by a nuclear reactor in a nuclear power plant. Nuclear fuel after nuclear reactor reactions contains a large amount of radioactive elements and therefore has a large amount of radioactivity, which, if not properly disposed of, can seriously affect the environment and the health of the personnel in contact with them. Therefore, spent fuel reacted by a nuclear reactor of a nuclear power plant needs to be stored in a spent fuel pool for several decades until its activity is reduced to a level where a subsequent post-treatment process for the spent fuel can be performed. With the increasing of domestic nuclear power plants and the continuous operation of the nuclear power plants, the spent fuel pool grillwork of most domestic nuclear power plants at present is full, and the existing container can not meet the requirement of spent fuel storage in the nuclear power plants, so the spent fuel pool storage capacity must be enlarged through transformation, and the normal production in the nuclear power plants is ensured.

When the spent fuel pool is expanded, firstly, an old framework in the spent fuel pool needs to be dismantled, and spent fuel in the old framework needs to be transported to the outside for storage before the old framework is dismantled, but the radioactivity of the spent fuel in the old framework is generally not reduced to the radioactivity value required by the transportation and subsequent spent fuel post-treatment process, so that great difficulty is brought to the transportation and storage of the spent fuel.

When transforming the storage capacity of the spent fuel pool, the spent fuel needs to be emptied, after the spent fuel is emptied, old grillwork needs to be dismantled, the dismantling of old grillwork is carried out for the first time at home and abroad, old grillwork is used for storing the spent fuel for a long time, and soak in the inside of the pool with radioactivity, can cause corresponding corrosion to the pool bottom of the pool, thereby cause the unevenness of the pool bottom, when being replaced into new grillwork after the old grillwork is dismantled, because the unevenness of the pool bottom can lead to the phenomenon that the grillwork is stored unstably to take place, in addition, when the grillwork is installed, because the radioactive substance is contained in the pool, the staff can not enter into the operation of assisting and observing the installation grillwork in the spent pool, the installation difficulty is very big.

Disclosure of Invention

The invention aims to provide a method for expanding a spent fuel pool of a million-kilowatt nuclear power plant, and aims to solve the technical problem that the storage requirement of spent fuel in the nuclear power plant cannot be met due to the full capacity of the spent fuel pool in the prior art.

In order to achieve the purpose, the invention adopts the technical scheme that: the method for expanding the spent fuel pool of the million kilowatt nuclear power plant comprises the following steps:

dismantling an old framework: moving the spent fuel in the old framework into a temporary storage framework, then hoisting the old framework placed in a spent fuel pool by using a first hoisting device, and transporting the old framework to a designated area by using transport equipment for storage;

leveling a high-density grid frame: leveling the high-density grillwork through a leveling device so as to adapt to the height of the bottom of the spent fuel pool;

and (3) high-density grid mounting: placing a high-density grid at the position of the old grid in the spent fuel pool by using a second hoisting device;

moving and mounting the spent fuel: and moving the spent fuel to the high-density grillwork for storage.

Further, the old framework removing step further comprises the following steps:

radiation measurement: and measuring the radiation level of the old grillwork put into the spent fuel pool to ensure that the old grillwork can be lifted out of the spent fuel pool.

Further, in the step of removing the old framework, the method further comprises the following steps:

the spent fuel around the old grillwork needs to be moved into the temporary storage grillwork.

The temporary storage grillwork comprises a first grillwork arranged in the loading well and a second grillwork arranged at the idle position of the spent fuel pool.

Further, the novel shelf also comprises a shielding plate, and the shielding plate is installed on the old shelf.

Further, the high-density grillwork is composed of a plurality of storage units for storing the spent fuel.

Further, each storage unit is made of cadmium materials.

Further, the center-to-center distance between adjacent storage units is 280 mm.

Further, the radiation measurement comprises the steps of:

taking out the spent fuel assemblies in the old grillwork and temporarily storing the spent fuel assemblies in the temporary storage grillwork;

and respectively selecting a plurality of points to be measured on the old framework at intervals, measuring the equivalent dose rate value of each point to be measured, and marking the position of each point to be measured and the measured value of each point to be measured.

Furthermore, the points to be measured are sequentially selected at equal intervals along the length direction of the grid unit.

Further, the old framework removal also comprises the following steps:

installing a vertical hoisting tool: arranging a plurality of first connecting ropes between the top of the old framework and the vertical hoisting tool;

installing a turning tool: installing a turnover plate at the bottom of the old grillwork;

hoisting the old grillwork to a transportation device: the vertical hoisting tool hoists the old grillwork to a preset height right above a placing plate of the transportation equipment, and the first connecting rope located right above the turnover plate is detached to enable the old grillwork to deflect towards one side;

transportation of the old grillwork: and the transport equipment transports the overturned old grillwork out of the factory building.

Further, the old framework removal also comprises the following steps:

mounting support assemblies at the bottom of the old framework, wherein the support assemblies and the turnover plates are positioned at two opposite ends of the old framework;

the transportation equipment enters the workshop in a reversing mode.

Further, the high-density grid installation step further comprises the following steps:

leveling the grillwork by measuring, namely measuring the unevenness of the spent fuel pool bottom by using a measuring device, and leveling the high-density grillwork by combining the measured unevenness;

and (4) grid mounting, namely hoisting the leveled high-density grid into the spent fuel pool, and positioning the high-density grid placed into the spent fuel pool.

and installing the high-density grillwork in the spent fuel pool according to the position marked by the nameplate.

and a positioning device is arranged on the high-density grillwork, so that the high-density grillwork is conveniently positioned.

Further, the positioning device comprises a positioning block for longitudinally pre-positioning the grid on the spent fuel pool bottom, and a positioning scale for transversely pre-positioning the grid on the spent fuel pool bottom.

detecting the cleanliness of the guide device placed at the bottom of the pool by using a camera;

according to the information feedback of the camera, if foreign matters exist on the guide device, cleaning the guide device by using a cleaning device;

repeating the above cleaning steps to ensure that the guiding device is clean.

and placing the underwater video device in the spent fuel pool through a third traction rope, and binding the third traction rope on a guardrail of the spent fuel pool.

before the measurement of the unevenness of the pool bottom, the cleanliness and the tightness of the long rod measuring device, the guiding device, the underwater video device and the camera are detected.

the second hoisting device is connected with the first traction rope, the guide device is hoisted to leave the pool bottom, and the guide device is moved to the next position of the pool bottom; and separating the second hoisting device from the first traction rope, wherein the first traction rope is bound on the hoisting guardrail of the spent fuel pool.

after the detection steps are repeated, the spent fuel pool hoisting device is used for hoisting the long rod measuring device, and then the long rod measuring device is inserted into the guide device to complete the measurement of the position below the pool.

and after the unevenness is measured, taking the long rod measuring device, the guide device and the camera out of the spent pool and storing the spent pool.

and leveling a grillwork, adjusting the height of the support leg of the bottom adjusting device according to the flatness, assembling the bottom adjusting device and the high-density grillwork after adjustment, and hoisting the assembled bottom adjusting device and the high-density grillwork into the spent fuel pool.

hanging the leveled grillwork into the spent fuel pool;

acquiring an underwater framework image by using the underwater video device, and transmitting the acquired image to an operator;

and carrying out underwater positioning on the high-density grillwork through a pushing device according to the image information.

Further, the high-density grid installation also comprises the following steps:

and (3) detecting the verticality of the grillwork: and performing plug-in and pull-out test on the high-density grillwork.

Further, the pushing device comprises an electric, hydraulic or pneumatic pushing device.

and connecting two adjacent high-density grillworks in the spent fuel pool through a connecting device.

and taking the pushing device and the positioning block out of the spent fuel pool through a second hoisting device, and collecting for later use.

The method for expanding the spent fuel pool of the million kilowatt nuclear power plant has the advantages that: compared with the prior art, the method for expanding the spent fuel pool of the million-kilowatt nuclear power plant comprises the steps of hoisting the old grillwork in the spent fuel pool by the first hoisting device, transporting the spent fuel pool to a designated area by utilizing transportation equipment for storage, leveling the high-density grillwork by the high-density grillwork, namely leveling the high-density grillwork by the leveling device to be matched with the height of the bottom of the spent fuel pool, then placing the high-density grillwork at the position of the old grillwork in the spent fuel pool by the second hoisting device, and finally moving spent fuel to the high-density grillwork for storage. The capacity expansion method provided by the invention solves the problem that the storage requirement of the spent fuel in the nuclear power station cannot be met due to the full capacity of the spent fuel pool, and provides possibility for continuously storing the spent fuel subsequently.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the embodiments or the drawings needed to be practical in the prior art description, and obviously, the drawings in the following description are only some embodiments of the embodiments, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a flowchart of a spent fuel pool capacity expansion method according to an embodiment of the present invention;

fig. 2 is a perspective view of an old framework according to an embodiment of the present invention;

FIG. 3 is a schematic view of an old grid and support assembly according to an embodiment of the present invention;

FIG. 4 is a schematic view of an old grid bottom structure according to an embodiment of the present invention;

FIG. 5 is a top view of a grasping element extending into a grid cell according to an embodiment of the present invention;

FIG. 6 is a schematic view of a grasping assembly extending into a grid cell according to an embodiment of the present invention;

FIG. 7 is a schematic view of a gripping state of the gripping mechanism according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a guide device according to an embodiment of the present invention;

FIG. 9 is an enlarged view of A in FIG. 8;

FIG. 10 is a schematic structural view of a long rod measuring device in an embodiment of the present invention;

FIG. 11 is an enlarged view of B in FIG. 10;

FIG. 12 is a schematic view of an assembly structure of the support frame and the long rod measuring device according to an embodiment of the present invention;

FIG. 13 is an enlarged view of C in FIG. 12;

FIG. 14 is a schematic structural diagram of a support stand according to an embodiment of the present invention;

figure 15 is a schematic diagram of a proposed lattice structure in an embodiment of the invention;

FIG. 16 is a front view of the connection of two adjacent grids according to the embodiment of the present invention;

fig. 17 is a schematic view of a connection assembly in an embodiment of the invention.

Wherein, in the figures, the respective reference numerals:

1-old grillwork; 100-a first base plate; 110-a grid cell; 111-a point to be measured; 1000-lifting hole;

2-high density grillwork; 21-a second bottom plate;

3-a leg assembly;

5-a long rod measuring device; 51-long rod body; 511-connecting rod; 52-a lifting lug; 520-an opening; 53-a detection head; 54-wire; 55-axis pin; 56-support hanging parts; 561-a first support ring; 562-a second support ring;

6-a guiding device; 61-a guide bar; 62-a first strut; 63-a second strut; 64-a third strut; 65-a guide mechanism; 66-connecting block; 67-a first pull cord; 68-a stop block; 650-a guide; 651-a positioning portion;

7-a support frame; 71-a support; 710-a support slot; 7101-arc portion; 7102-notches; 72-a fixed part; 721-plate; 722-a first riser; 723-a second riser;

8-a pool wall;

9-turning over the board; 91-a horizontal portion; 92-a vertical portion; 93-an arc;

10-connecting assembly, 101-connecting plate; 102-a first positioning plate; 103-a second positioning plate; 104-temporary screws; 105-final screw;

11-a first hoisting device; 1100-a grasping element; 1101-a first hoisting beam; 1102-a first lifting rod; 1103-grabbing the mounting plate; 1104-a grasping mechanism; 1105-a grasping drive mechanism; 1106-a transfer mechanism; (ii) a 1107-return spring; 11041-grasping claws; 11042-rotation pin; 11051-top block; 11052-mandril; 11042-arc surface; 11061-vertical push rod; 11062-push the push rod down;

12-a support assembly; 121-a first support plate; 122 — a second support plate; 1211 — a first connecting frame; 1221-second connecting frame.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements may also be present.

It should be noted that the terms of orientation such as left, right, up and down in the embodiments of the present invention are only relative concepts or reference to the normal use state of the product, and should not be considered as limiting, and the implementation of the present invention will be described in detail with reference to the specific embodiments below.

Referring to fig. 1 to 17, the present invention provides a method for expanding a spent fuel pool of a million kilowatt nuclear power plant, comprising the following steps:

dismantling an old framework: moving the spent fuel in the old framework 1 into a temporary storage framework, then hoisting the old framework 1 placed in a spent fuel pool by using a first hoisting device 11, and transporting the spent fuel to a designated area by using transportation equipment for storage;

and (3) high-density grid mounting: placing a high-density framework 2 at the position of an old framework 1 in a spent fuel pool by using a second hoisting device;

moving and mounting the spent fuel: and moving the spent fuel to the high-density framework 2 for storage.

The method comprises the steps of hoisting the old grillwork 1 in the spent fuel pool by the first hoisting device 11, transporting the old grillwork to a designated area by using transport equipment for storage, leveling the high-density grillwork by the high-density grillwork, namely leveling the high-density grillwork by the leveling device to be matched with the height of the bottom of the spent fuel pool, and placing the high-density grillwork 2 at the position of the old grillwork 1 in the spent fuel pool by the second hoisting device.

Preferably, the old framework removing step further comprises the following steps:

radiation measurement: the radiation level measurement is carried out on the old grillwork 1 placed in the spent fuel pool, so as to ensure that the old grillwork 1 can be lifted out of the spent fuel pool.

The radiation level of the old grillwork 1 placed in the spent fuel pool is measured, so that the radiation level of the old grillwork 1 is ensured to be at a safety value when the old grillwork 1 is lifted out of the spent fuel pool, and the old grillwork 1 can be lifted out of the spent fuel pool when the radiation level of the old grillwork 1 is at the safety value.

Preferably, before the old framework removing step, the method further comprises the following steps:

grid positioning: installing a positioning nameplate on the side wall of the spent fuel pool; so that the grillwork is stored in advance according to the position of the positioning nameplate; therefore, the grid frame can be stored in advance according to the position of the positioning nameplate by installing the positioning nameplate on the side wall of the spent fuel pool.

In the present invention, the old framework demolishing step further includes the following steps:

the spent fuel around the old grillwork 1 needs to move into the temporary storage grillwork.

The spent fuel near the old framework 1 is moved into the temporary storage framework (not shown in the attached drawing), so that on one hand, the spent fuel near the old framework 1 is guaranteed to be touched when the old framework 1 is operated, and on the other hand, the influence caused by the spent fuel near the old framework 1 is avoided when the radiation measurement is carried out on the old framework 1, and the result detection is inaccurate.

In the present invention, the periphery is represented as a lattice adjacent to the old lattice 1.

Preferably, the temporary storage grid comprises a first grid arranged in the loading well of the loading well and a second grid arranged at the vacant position of the spent fuel pool. Therefore, the spent fuel in the old framework 1 and the spent fuel around the old framework 1 can be moved to the first framework or the second framework for temporary storage.

Preferably, a shielding plate (not shown in the attached drawings) is further installed on the spent fuel pool, and the shielding plate can be installed on the old grillage 1, so that when the grillage is hoisted and moved, if spent fuel is stored below the movement of the grillage, the dead fuel can be prevented from being hit by the inadvertent falling of the grillage in the moving process by installing the shielding plate, and the safety in the moving process is further ensured. Of course, the shielding plate may be installed on a high-density grid or on a loading well so as to shield the grid installed in the loading well, and is not limited herein.

Preferably, the high-density rack 2 is formed of a plurality of storage units for storing spent fuel, each storage unit is a rectangular parallelepiped chamber having one side opened, and the opening is upward, so that the spent fuel can be stored in the chamber through the opening, and further, in the present invention, the high-density rack 2 is a 4 × 7/7 × 7/8 × 7 type, preferably, the 4 × 7 type here indicates that 4 storage units are arranged in the transverse direction of the high-density rack 2, and 7 storage units are arranged in the longitudinal direction of the high-density rack 2, and similarly, the 7 × 7/8 × 7 type is a corresponding explanation, and will not be described herein.

Preferably, each storage unit is made of cadmium material, and the center distance of the storage units is 280mm, although the center distance may be set to other values, which is not limited herein.

Preferably, in the present invention, 15 high-density frames 2 of 36 storage units and 5 high-density frames 2 of 30 storage units are installed in the spent fuel pool, so as to accommodate 690 storage units, although other storage units may be installed in the spent fuel pool, which is not limited herein.

In the invention, the old framework 1 is the old framework in the spent fuel pool, and the high-density framework 2 is the new framework needing to replace the old framework 1.

Preferably, the radiation level measurement comprises the steps of:

taking out the spent fuel assemblies in the old grillwork 1 to temporarily store the spent fuel assemblies in the temporary grillwork;

a plurality of points to be measured 111 are respectively selected at intervals on the old framework 1, the equivalent dose rate value of each point to be measured 111 is measured, and the position of each point to be measured 111 and the measured value of each point to be measured are marked.

In the invention, when the radiation measurement is carried out on the old framework 1, firstly the spent fuel assembly needs to be taken out to ensure the influence of the spent fuel assembly on the measurement, then a plurality of points to be measured are respectively selected at intervals on the old framework 1 to realize whether the old framework 1 meets the radiation equivalent value, and the measured points to be measured 111 are marked to show the measured values. And the instruments, tools, and specific labeling modalities employed in the labeling step are not limited herein; through selective marking of the measuring result, the position with higher radiation intensity on the whole old grillwork 1 can be clear at a glance, marking efficiency is improved, and meanwhile, a good foundation is laid for subsequent radiation protection operation of the old grillwork 1.

Preferably, referring to fig. 2, the old rack 1 includes a plurality of rack units 110 for accommodating nuclear fuel, and the plurality of rack units 100 may be arranged in a longitudinal and transverse direction and are respectively numbered one by capitalization letters and arabic numerals, so that each rack unit 110 can be accurately positioned by combining the two, for example, a1 rack unit, B3 rack unit, etc., and the opening shape of each rack unit may be rectangular, although the arrangement, numbering and opening shape of the plurality of rack units may be other, and are not limited herein.

Preferably, a plurality of points to be measured 111 are selected at intervals in each grid cell 110, and the radiation equivalent dose value at each point to be measured 111 is measured, in this embodiment, the radiation equivalent dose value is used as a measure of the radiation intensity at each point to be measured 111, of course, if different measuring instruments are selected or reasons such as accuracy requirements exist, the radiation intensity at each point to be measured 111 can also be measured by using other indexes, so that the measurement of the radiation equivalent dose value at each point to be measured 111 here is only a preferred embodiment of the present invention, and has no limit; specifically, each grid cell 110 is a rectangular parallelepiped first chamber having an opening at one side, and the plurality of points to be measured 111 in each grid cell 110 are sequentially and equally spaced along the length direction of the grid cell 110.

Further, the number of the to-be-measured points 111 in the grid cell of a1 is specifically four, the first to-be-measured point 111 is located at the bottom surface of the grid cell 110, then the other three to-be-measured points 111 are sequentially arranged at equal intervals along the length direction, and the interval between two adjacent to-be-measured points 111 is defined to be 800 mm-1200 mm, and is preferably 1000mm here.

Preferably, the radiation measurement further comprises the steps of:

if the radiation level value of the point to be measured 111 is not greater than the first preset value, performing a first protection operation on the old framework 1;

if the radiation level of the point to be measured 111 is greater than the first preset value and not greater than the second preset value, performing a second protection operation on the old framework 1;

and if the radiation level of the point to be measured 111 is greater than the second preset value, performing third protection operation on the old grillwork 1.

Preferably, the first preset value is 2ms v/h (milli-schff/h), the second preset value is 10ms v/h, and the third preset value is 1ms v/h, although other values may be selected as the first preset value or the second preset value according to practical situations, and the first preset value or the second preset value is not limited herein.

Preferably, the radiation measurement further comprises the steps of:

when the measured value of the point 111 to be measured is greater than a third preset value, the position and the measured value of the point 111 to be measured need to be marked, and if the measured value at a certain point 111 to be measured is not greater than the third preset value, the position and the measured value of the point 111 to be measured are not marked.

Specifically, the first protection operation includes the following steps:

removing the old trellis 1 from the spent fuel pool into a preparation well 15 located near the spent fuel pool; subsequently, the old grid 1 is subjected to an above-water external surface washing operation.

That is, when the measured values of all the points 111 to be measured in the old grid 1 are not greater than the first preset value, that is, when the measured values of all the points 111 to be measured of each grid unit 110 in the old grid 1 are less than or equal to 2mSv/h, the first protection operation is implemented, it should be noted that, in this embodiment, the water external surface washing operation is to wash the outer wall surface of the old grid 1 by using a specific external surface washing device and SED demineralized water (i.e., demineralized water used by the nuclear island demineralized water distribution system), and it is not necessary to wash the inner surface of the chamber 10 of the old grid 1, so that the external radiation protection of the old grid 1 is realized, and the working efficiency is improved.

Specifically, the second protection operation includes the following steps:

performing an underwater washing operation on the inner surface of the lattice unit 110 in the spent fuel pool;

measuring and marking the radiation equivalent dose rate value of the old framework 1 again;

if the value obtained by the measurement again is not larger than the first preset value, the old framework 1 is moved out of the spent fuel pool to a preparation well near the spent fuel pool, and the water surface and the outer surface of the old framework 1 are washed in the preparation well;

if the measured value is still greater than the first preset value and not greater than the second preset value, the old framework 1 is moved out of the spent fuel pool into a preparation well, the underwater inner surface washing operation is firstly carried out on the old framework 1 in the preparation well, and then the underwater outer surface washing operation is carried out on the old framework 1 in the preparation well.

Preferably, when the radiation amount of the to-be-measured points 111 of the old grid 1 is greater than the first preset value and not greater than the second preset value, that is, the second protection operation is performed, the old grid 1 is removed from the spent fuel pool to the preparation well, the grid units 110 of the old grid 1 are firstly subjected to an underwater inner surface washing operation in the preparation well, and then the old grid 1 is subjected to an underwater outer surface washing operation in the preparation well, it should be noted that in this embodiment, the underwater washing operation is to wash the inner walls of the grid units 110 of the old grid 1 through a specific underwater washing decontamination device and SED demineralized water to remove loose contamination in the grid units 110, so as to achieve radiation protection inside the grid units 110 in the old grid 1.

Specifically, the third protection operation includes the following steps:

if the measured value is not greater than the second preset value, the old grillwork 1 is moved out of the spent fuel pool to a preparation well near the spent fuel pool; if the numerical value is not greater than the first preset value, performing water surface and external surface washing operation on the old grillwork 1 in a preparation well;

if the value obtained by re-measurement is larger than the first preset value and not larger than the second preset value, firstly carrying out underwater inner surface washing operation on the old framework 1 in the preparation well, and then carrying out water upper outer surface washing operation on the old framework 1 in the preparation well;

and if the measured value is still larger than the second preset value, performing radiation protection treatment on the old framework 1 according to a preset emergency scheme.

It should be noted that, in this embodiment, the preset emergency schemes may be as follows:

1. when the spent fuel pool is expanded, the grillage in the spent fuel pool does not need to be completely removed, so that if the re-measured value of the old grillage 1 is still greater than the second preset value, the old grillage 1 can be discarded to be removed, and the rest grillages can be removed;

2. carrying out underwater inner surface washing operation on the grid units in the old grid 1 in a spent fuel pool, and also washing the points to be measured 111 with the measured values still larger than a second preset value in a targeted manner so as to reduce the radiation intensity of the whole old grid 1;

3. in practice, it is mostly necessary to arrange the first bottom plate 100 at the bottom of the old framework 1 (i.e. the bottom surface of the framework unit 110 in the old framework 1), and the radiation intensity of the first bottom plate 100 is usually the highest point in the framework unit 110, so that the first bottom plate of the old framework 1 can be removed by using a specific clamp, and then the spent fuel pool is removed after the overall radiation intensity is reduced.

Of course, other emergency measures must exist according to different actual operation conditions, and the above is only the preferred scheme of the embodiment; through setting up above a plurality of preset emergency schemes, can make operating personnel from the radiation condition of actual framework, because of the thing is fit for, preferred selection has optimized the framework radiation protection process flow when having promoted spent fuel pool expansion efficiency.

Further, referring to fig. 6 and 7, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the first hoisting device 11 includes a grabbing assembly 1100 for cooperating with the hoisting hole 1000 of the first base plate 100, a first hoisting beam 1101 for mounting the grabbing assembly 1100, and a driving device for driving the first hoisting beam 1101 to move; the grabbing assembly 1100 comprises a first hoisting rod 1102 fixedly connected with the first hoisting beam 1101 and in a hollow shape, a grabbing mounting plate 1103 arranged at one end of the first hoisting rod 1102 far away from the first hoisting beam 1101, at least one grabbing mechanism 1104 arranged on the grabbing mounting plate 1103, and a grabbing driving mechanism 1105 arranged inside the first hoisting rod 1102 and used for driving the grabbing mechanism 1104 to complete grabbing.

In the invention, a plurality of lifting holes 1000 are respectively arranged on the first bottom plate 100 at the corresponding position at the bottom of each grid unit 110, the grabbing assemblies 1100 are used for grabbing the first bottom plate 100 of the old grid 1 through the first lifting holes 1000, the first lifting beams 1101 are used for installing a plurality of grabbing assemblies 1100, and the driving device is used for driving the first lifting beams 1101 to move in the horizontal direction and the vertical direction.

In this embodiment, the using process of the hoisting device for the spent fuel pool expansion used grillwork 1 is as follows: the driving device drives the first hoisting beam 1101 to a preset position, so that each grabbing assembly 1100 is respectively positioned at the top of one grid unit 110, the driving device drives the first hoisting beam 1101 to move vertically downward, so that the first hoisting rod 1102 in each grabbing assembly 1100 extends into the grid unit 110, the grabbing driving mechanism 1105 arranged inside the first hoisting rod 1102 drives the grabbing mechanism 1104 to make the grabbing mechanism 1104 in a released state (i.e., a non-grabbing state), and after the grabbing mechanism 1104 penetrates through the hoisting hole 1000, the grabbing driving mechanism 1105 drives the grabbing mechanism 1104 to make the grabbing mechanism 1104 in a grabbing state (i.e., the grabbing mechanism 1104 clamps the bottom of the old grid 1); then the driving device drives the first hoisting beam 1101 to move vertically upwards, the grabbing assembly 1100 grabbing the old framework 1 takes the old framework 1 away from the bottom of the spent fuel pool and rises to a certain height in the process of moving upwards along with the first hoisting beam 1101 until the old framework 1 completely leaves the spent fuel pool, and then the old framework 1 is lifted out of the spent fuel pool in the dismantling process.

Specifically, the step of removing the old framework includes the following steps:

firstly, the driving device moves in the horizontal direction, and the grabbing assembly 1100 arranged on the first hoisting beam 1101 is hoisted to the position right above the old grillwork 1; subsequently, the driving device moves in the vertical direction to extend the grasping assembly 1100 in the released state into the grid unit 110 of the old grid 1 and to extend the grasping mechanism 1104 into the hoisting hole 1000; then, the grabbing driving mechanism 1105 drives the grabbing mechanism 1104 to complete grabbing; finally, the old framework 1 is lifted out of the spent fuel pool to the preparation well.

Further, referring to fig. 6, as a specific embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the grabbing mechanism 1104 includes two grabbing claws 11041 arranged oppositely, and each grabbing claw 11041 is rotatably connected to the grabbing mounting plate 1103; the grabbing driving mechanism 1105 comprises a top block 11051 for driving the grabbing claw 11041 to rotate, and a top rod 11052 connected with the top block 11051; each of the grasping claws 11041 has an arc surface 11042, and the top piece 11051 abuts against each of the arc surfaces 11042. Specifically, the center of a circle of the arc surface 11042 provided on the grasping claw 11041 is located outside the grasping claw 11041, and thus the arc surface 11042 is formed concavely for the grasping claw 11041; the top block 11051 is positioned between the two grabbing claws 11041 of the grabbing mechanism 1104, namely the top block 11051 is simultaneously abutted with the two grabbing claws 11041 of one grabbing mechanism 1104; the grabbing and releasing processes of the grabbing mechanism 1104 are as follows: when the top block 11051 moves in a direction approaching the grasping mechanism 1104, the top block 11051 moves along the arc surface 11042 and rotates the two grasping claws 11041 on one grasping mechanism 1104 in a direction away from the other grasping claw 11041 through the arc surface 11042, so that the grasping mechanism 1104 is in an open non-grasping state; when the top block 11051 moves in a direction away from the gripping mechanism 1104, the top block 11051 moves along the arc surface 11042 and rotates in a direction in which the two gripping claws 11041 of one gripping mechanism 1104 are respectively pushed toward the other gripping claw 11041 by the arc surface 11042, so that the gripping mechanism 1104 is in a tightly gripped state.

Further, please refer to fig. 6, which is a specific embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, further including an external driving mechanism for driving the lift rod 11052 to move along the axis of the first lifting rod 1102, and a transmission mechanism 1106 disposed between the lift rod 11052 and the external driving mechanism; the transmission mechanism 1106 includes a vertical push rod 11061 abutting on one end of the push rod 11052 far from the push block 11051; the external driving mechanism includes a first long rod body and a lower pressing head provided at an end of the first long rod body and used for pushing the vertical push rod 11061 to move. Specifically, the first long rod body is pushed to drive the lower pressure head to move, the lower pressure head drives the vertical push rod 11061 to move inside the first hoisting rod 1102 along the axis of the first hoisting rod 1102 in the moving process, the vertical push rod 11061 drives the push rod 11052 to move inside the first hoisting rod 1102 along the axis of the first hoisting rod 1102 when the first hoisting rod 1102 moves inside the first hoisting rod 1102 due to the fact that the vertical push rod 11061 is abutted to the push rod 11052, and the top block 11051 arranged at the end part of the push rod 11052 moves along with the movement of the push rod 11052.

Further, referring to fig. 6, as a specific implementation manner of the method for expanding the spent fuel pool of the million kilowatt-level nuclear power plant provided by the present invention, the transfer mechanism 1106 further includes a rotary push-down rod 11062 disposed at one end of the vertical push rod 11061 away from the push rod 11052, the first hoisting rod 1102 is provided with a sliding limiting groove structure, and the rotary push-down rod 11062 is slidably connected to the first hoisting rod 1102 through the sliding limiting groove structure; the sliding limiting groove structure comprises a horizontal groove, a first vertical groove and a second vertical groove, wherein the first vertical groove is arranged at one end of the horizontal groove and extends in the direction away from the grabbing mechanism, and the second vertical groove is arranged at the other end of the horizontal groove and extends in the direction away from the grabbing mechanism 1104; the length of first vertical groove is greater than the length of second vertical groove, and lower pressure head is seted up and is used for and rotates push down push rod 11062 matched with rotation and pushes down the groove, is equipped with reset spring 1107 between ejector pin 11052 and the first hoist and mount pole 1102. Specifically, the rotating push-down rod 11062 provided on the vertical push rod 11061 is used for being matched with a rotating push-down groove provided on the push-down head, the rotating push-down groove is sleeved outside the rotating push-down rod 11062, the push-down head is driven to rotate when moving linearly, the rotating push-down rod 11062 is driven to move linearly, and the push-down head is driven to rotate when rotating, the push-down rod 11062 is driven to rotate. The process that the lower pressure head drives the rotary lower pressure push rod 11062 to do linear motion and rotate is as follows: the first long rod body is pushed to drive the lower pressing head to move, the lower pressing head drives the rotary lower pressing push rod 11062 to move inside the first hoisting rod 1102 along the axis of the first hoisting rod 1102 in the moving process, and the rotary lower pressing push rod 11062 moves along the first vertical groove, so that the linear motion of the rotary lower pressing push rod 11062 is driven, when the rotary lower pressing push rod 11062 moves to the end part of the first vertical groove and is horizontal to the horizontal groove (the push rod 11052 is moved a certain distance in the first hoisting rod 1102 in the process of rotating the lower pressing push rod 11062 to move along the first vertical groove, so that the top block 11051 pushes the grabbing mechanism 1104 to a loosening state, the reset spring 1110 is compressed in the process), the first long rod body 6 is rotated to drive the lower pressing head 1109 to rotate, the rotary lower pressing push rod 11062 rotates a certain angle along the horizontal groove along with the rotation of the lower pressing head to reach the end part of the second vertical groove, and at the moment, the first long rod body moves in the direction far away from the first hoisting rod 1102, the return spring 1110 pushes the vertical push rod 11061 to drive the rotary push-down push rod 11062 to move to one end of the second vertical groove far away from the horizontal groove along the second vertical groove, at the moment, the second vertical groove limits the rotary push-down push rod, so that the rotary push-down push rod 11062 cannot rotate, namely, the position of the push rod 11052 is fixed, and therefore the grabbing mechanism 1104 controlled by the push rod 11052 driving the push block 11051 also keeps a loosened state. When it is desired to keep the gripping mechanism 1104 in the gripping state as well, following the reverse steps described above: that is, the rotating push-down rod 11062 in the second vertical slot is pushed down into the horizontal slot 11063 and then reversely rotates to the end of the first vertical slot, and the rotating push-down rod 11062 moves to the end of the first vertical slot far away from the horizontal slot along the first vertical slot due to the action of the return spring 1107. Because the length of the first vertical slot is greater than the length of the second vertical slot, the top block 11051 pushes the gripper mechanism 1104 into a gripping state when the rotary push-down bar moves along the first vertical slot to the end of the first vertical slot away from the horizontal slot 11073; when the rotary push-down lever 11072 moves along the second vertical direction to the end away from the horizontal slot, the top block 11051 pushes the grip mechanism 1104 to be in the released state. For example, the length of the first vertical slot is 50 mm, and the length of the second vertical slot is 10 mm; in the process that the end part of the first vertical groove far away from the horizontal groove is moved to the horizontal groove and then reaches the end part of the second vertical groove far away from the horizontal groove, the push rod 11052 moves 40 mm towards the direction close to the grabbing mechanism 1104 along the axis of the first hoisting rod 1102, namely, the push block 11051 arranged at the end part of the push rod 11052 moves 40 mm towards the direction close to the grabbing mechanism 1104 along the axis of the first hoisting rod 1102 along with the push rod 11052. The two ends of the return spring 1110 are respectively connected with the inner walls of the push rod 11052 and the first hoisting rod 1102, so that the push rod 11052 compresses the return spring 1110 when approaching the grabbing mechanism 1104, and when the push rod 11052 does not receive external force or external force released from the grabbing mechanism 1104, the push rod 11052 is pushed to move away from the grabbing mechanism 1104 by the elastic force of the return spring 1110.

Further, referring to fig. 6 and 7, as a specific embodiment of the method for expanding the volume of the spent fuel pool of the megawatt nuclear power plant provided by the present invention, the number of the grabbing mechanisms 1104 is two, the grabbing mounting plate 1103 is provided with a mounting groove for mounting the grabbing claw 11041, and a rotating pin 11042 is disposed between the grabbing claw 11041 and a side wall of the mounting groove. Specifically, the number of the hoisting holes 1000 at the bottom of each grid unit 110 is 4, and the number of the grabbing mechanisms 1104 is two, that is, four grabbing claws 11041 correspond to one hoisting hole 1000 respectively; the four directions of the top block 11051 are abutted with the arc surface 11042, namely the top block 11051 is simultaneously abutted with the four grabbing claws 11041 on the two grabbing mechanisms 1104; the grabbing and releasing processes of the grabbing mechanism 1104 are as follows: when the top block 11051 moves toward the direction approaching the grasping mechanism 1104, the top block 11051 moves along the arc surface 11042 and rotates one grasping mechanism 1104 (here, it is possible to control two grasping claws 11041 of the two grasping mechanisms 1104 to respectively push away from the other grasping claw 11041) through the arc surface 11042, so that the grasping mechanisms 1104 are in an open non-grasping state.

In addition, the old framework dismantling step further comprises the following steps:

installing a vertical hoisting tool: arranging a plurality of first connecting ropes between the top of the old framework 1 and the vertical hoisting tool;

installing a turning tool: a turnover plate 9 is arranged at the bottom of the old grillwork 1,

hoisting the old grillwork 1 to transportation equipment: the vertical hoisting tool hoists the old grillwork 1 to a preset height right above a placing plate of the transportation equipment, and a first connecting rope right above the turnover plate 9 is removed to enable the old grillwork 1 to deflect towards one side;

in the invention, the turnover plate 9 comprises a horizontal part 91 connected with the bottom of the old grillwork 1, a vertical part 92 arranged in parallel with the side plate of the old grillwork 1, and an arc part 93 positioned between the horizontal part 91 and the vertical part 92; thus, the turnover plate is arranged, so that the old grillwork 1 can be conveniently installed on the transportation equipment.

Further, sleepers are arranged on the transportation equipment, so that the vertical hoisting tool slowly descends the deflected old grillage 1 to enable the vertical part 92 of the turnover plate 9 to be abutted against the sleepers, and the vertical hoisting tool drives the old grillage 1 to transversely move to enable the old grillage 1 to be slowly turned over to the placing plate;

the transportation equipment transports the overturned old grillwork 1 out of the factory.

mounting the support assembly 12: mounting a support assembly 12 at the bottom of the old grillwork 1, wherein the support assembly 12 and the turnover plate 9 are positioned at two opposite ends of the old grillwork 1;

the transportation equipment enters a workshop in a reversing mode;

specifically, the supporting component 12 with the same thickness as the turnover plate 9 is arranged on the opposite side of the turnover plate 9, so that the bottom of the old grillwork 1 for installing the turnover plate 9 is ensured to be flat, and the unstable placement of the old grillwork 1 is avoided. The first isolation door is closed before the second isolation door is opened, radiation is prevented from being spread outwards through the first isolation door, and operation safety is guaranteed.

Further, referring to fig. 3, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the support assembly 12 includes a first support plate 121 and a second support plate 122 disposed parallel to the first support plate 121, and a length of the first support plate 121 is different from a length of the second support plate 122. Specifically, the supporting assembly 12 comprises two separated first supporting plates 121 and second supporting plates 122, the length of the first supporting plate 121 is different from that of the second supporting plate 122, when a certain connecting portion at the bottom of the old grillwork 1 cannot be used due to rust, corrosion and the like, another connecting portion can be replaced to connect the first supporting plate 121 and the second supporting plate 122, so that the first supporting plate 121 and the second supporting plate 122 are ensured to extend out of the bottom of the old grillwork 1 by the same length after being connected with the old grillwork 1, and subsequent horizontal hoisting is facilitated.

Further, referring to fig. 3, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to the present invention, the first support plate 121 is provided with a first connecting bracket 1211, the first support plate 121 is bolted to the bottom of the old framework 1 through the first connecting bracket 1211, the second support plate 122 is provided with a second connecting bracket 1221, and the second support plate 122 is bolted to the bottom of the old framework 1 through the second connecting bracket 1221. Specifically, the first connection bracket 1211 and the second connection bracket 1221 are each of an inverted U-shaped structure for penetrating bolts to facilitate connection between the first support plate 121 and the second support plate 122 and the bottom of the old framework 1.

Preferably, the high-density grid installation comprises the following steps:

cleaning the pool bottom, namely cleaning the pool bottom of the spent fuel pool by adopting a cleaning tool;

leveling the grillwork by measuring, namely measuring the unevenness of the spent fuel pool bottom by a measuring device, and leveling the high-density grillwork 2 by combining the measured unevenness;

and (4) grid mounting, namely, hoisting the leveled high-density grid 2 into the spent fuel pool, and positioning the high-density grid 2 placed into the spent fuel pool.

In the invention, the bottom of the spent fuel pool is firstly cleaned, so that the influence of impurities existing in the spent fuel pool on a subsequent measuring device is avoided; the unevenness of the pool bottom is measured, and the high-density grillwork 2 is leveled by combining the measured unevenness, so that the subsequent grillwork 2 is stably placed in a spent pool; then, the leveled high-density grillwork 2 is hung into a spent fuel pool, and the high-density grillwork 2 placed in the spent fuel pool is positioned; by the grid frame installation process provided by the invention, workers can complete the installation operation of the grid frame without entering the spent fuel pool, so that the underwater installation of the grid frame becomes possible.

Preferably, the step of installing the high-density grid frame further comprises the following steps:

the high-density grillwork 2 is provided with a positioning device, so that the subsequent grillwork 2 can be conveniently positioned in a pool.

the high-density grillwork 2 is arranged in the spent fuel pool according to the position marked by the nameplate, so that the observation and the operation of workers are convenient.

Specifically, the positioning device comprises a positioning block for longitudinally pre-positioning the high-density grillwork 2 at the bottom of the spent fuel pool and a positioning scale for transversely pre-positioning the grillwork at the bottom of the spent fuel pool, and the positioning block and the positioning scale are arranged, so that the high-density grillwork 2 is transversely and longitudinally positioned.

In the present invention, the transverse orientation may be a longitudinal direction of the high-density lattice 2 and the longitudinal direction may be a width direction of the high-density lattice 2, but in the present invention, the transverse orientation may also be a width direction of the high-density lattice 2 and the longitudinal direction may be a length direction of the high-density lattice 2, and is not limited herein.

placing the guide device 6 at a designated position at the bottom of the pool by using a second hoisting device;

a long rod measuring device 5 is inserted into the guide device 6, and a level gauge (not shown in the attached drawing) for monitoring the flatness of the bottom of the spent fuel pool is installed at one end of the long rod measuring device 5, which is far away from the guide device 6.

In the invention, the staff is arranged below the long rod measuring device 5, and the level gauge is arranged at the top end of the long rod measuring device 5, so that when the long rod measuring device 5 extends into the guide device 6 to measure the unevenness of the pool bottom, if the pool bottom is uneven, the level gauge changes correspondingly, and then the scale of the staff on the long rod measuring device 5 is read by the level gauge, so that the measurement of the pool bottom is realized, and the guarantee is provided for the bottom adjustment of the subsequent high-density grillwork 2.

the guide means 5 is placed at a designated position at the bottom of the pool using the lifting device and the first traction rope 67. Thus, the guiding device 5 can be placed in the pool bottom through the hoisting device and the first traction rope 67, and in the invention, the designated position is the position to be measured at the bottom of the spent fuel pool.

placing the guide device 6 at a designated position on the pool through a second traction rope;

the underwater placement position of the guiding device 6 is determined by a laser distance measuring instrument (not shown in the figure);

the spent fuel pool hoisting device is connected with the first traction rope, the first traction rope 67 is connected with the guiding device 6, and the second traction rope is matched with the spent fuel pool hoisting device and the first traction rope 67 to slowly place the guiding device 6 at the designated position of the pool bottom.

In this way, by connecting the second traction rope with the guiding device 6, the guiding device 6 can be placed in the water slowly by the follow-up staff by pulling the second traction rope; the underwater placement position of the guiding device 6 can be accurately positioned underwater by using the laser range finder, so that the subsequent measurement of the unevenness of the pool bottom is facilitated; through linking to each other first haulage rope 67 with guider 6, link to each other with first haulage rope 67 through spent fuel pond hoist device afterwards, like this, thereby realize slowly placing guider 6 in the aquatic through second haulage rope, hoist device, first haulage rope 67.

detecting the cleanliness of the guide device 5 placed at the bottom of the pool by using a camera;

according to the information feedback of the camera, if foreign matters exist on the guide device 5, cleaning the guide device 5 by using a cleaning tool;

the above cleaning steps are repeated to ensure that the guiding means 5 is clean.

By this step, it is avoided that the guide 6 is contaminated and the accuracy of the measurement of the unevenness of the bottom of the tank is affected.

In the invention, the guide device 6 is positioned underwater, so that the long rod measuring device 5 can be conveniently guided and positioned to realize measurement; the cleanliness of the guide device 6 placed under water is detected to detect whether the guide device 6 is influenced in the water pool or not, so that the influence on the long rod measuring device 5 in the detection process is avoided; the unevenness of the pool bottom is measured by the long rod measuring device 5, the guide device 6 and the level gauge, and the unevenness of the pool bottom is measured by the unevenness measuring and leveling device, so that the flatness of the pool bottom is measured, and a guarantee is provided for replacing an old lattice frame with a new lattice frame subsequently.

Preferably, the above-mentioned camera (not shown in the drawings) is installed on the long rod measuring device 5, so that when the long rod measuring device 5 is inserted into the water, the camera can be inserted into the water together with the long rod measuring device 5, so as to detect the cleanliness of the guiding device 6 placed in the water pool, and the detection is simple and convenient, and certainly, the camera can be placed in the water by other modes, and the detection is not limited here.

and the underwater video device is placed in the pool through a third traction rope, and the third traction rope is tied on a guardrail of the spent fuel pool.

Therefore, by placing the underwater video device in water, the condition of the pool bottom can be known, and the measurement of a subsequent measuring device is facilitated; the underwater video device can monitor the measurement condition in water in real time, and in the invention, the underwater video device is installed on the high-density grillwork 2 in the spent fuel pool, and of course, the underwater video device can also be installed at other positions, and the underwater video device is not limited uniquely here.

Preferably, the underwater video device is installed on an idle grid in the spent fuel pool, but the underwater video device may be installed at other positions, which is not limited herein.

when the unevenness of the pool bottom is measured, the cleanliness and the tightness of the long rod measuring device 5, the guiding device 6, the underwater video device and the camera are detected; therefore, the unevenness measuring device is detected in advance, so that the influence of the detecting device on the measuring process is avoided; and the measurement error is reduced, and the measurement precision is improved.

Further, referring to fig. 8, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the guide device 6 comprises a guide rod 61, a first support rod 62, a second support rod 63 and a third support rod 64 which are respectively arranged on the guide rod 61, the first support bar 62, the second support bar 63 and the third support bar 64 are distributed on the guide bar 61 at intervals, and the first strut 62, the second strut 63, and the third strut 64 are all provided in a direction perpendicular to the axial direction of the guide bar 61, and further, a guide mechanism 65 is mounted on each of the first stem 62, the second stem 63, and the third stem 64, this guiding mechanism 65 can be used to guide the above-mentioned stock measuring device 5 to be vertical state and to position the above-mentioned stock measuring device 5 to realize the subsequent measurement to the bottom of the pool unevenness.

Further, referring to fig. 9, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to the present invention, the guiding mechanism 65 may be used to guide and position the long rod measuring device 5, the guiding mechanism 65 includes a guiding portion 650 and a positioning portion 651 disposed at a lower end of the guiding portion, and the guiding portion 650 and the positioning portion 651 are located in the same axial direction. Thus, by providing a plurality of guide mechanisms 65, the long rod measuring device 5 can be guided and positioned at different positions to be measured.

Specifically, referring to fig. 9, the guide portion is disposed in an inverted conical shape, and a channel (not shown) for the long rod measuring device 5 to pass through is formed on the guide portion 650, and a positioning hole (not shown) for positioning the long rod measuring device is formed on the positioning portion 651, and the channel and the positioning hole are located in the same axial direction and are communicated with each other. In this way, the long rod measuring device 5 can pass through the passage in the guide 650 and extend into the positioning hole in the positioning portion 651 to achieve positioning of the long rod measuring device 5.

the long rod measuring device 5 is inserted into the positioning hole through the second hoisting device 12, so that the unevenness of the pool bottom can be measured.

Further, referring to fig. 8, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, a plurality of connecting blocks 66 are disposed on the guiding rod 61, and the connecting blocks 66 can be connected to the first hauling cable 67. Specifically, each of the connection blocks 66 is provided with a second through hole (not shown) for the first pulling rope 67 to pass through, so that the first pulling rope 67 can pass through the second through hole and then be bound to the connection block 66, thereby realizing the connection between the first pulling rope 67 and the connection block 66.

Further, referring to fig. 8, as an embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the guiding device 6 is further provided with a plurality of stoppers 68 for abutting against the idle grids in the pool to position the third supporting rod 64, and each stopper 68 is mounted on the third supporting rod 64. In this way, by mounting the stop 68 on the third strut 64, on the one hand, it is possible to position the guide device 6 accurately under water, and on the other hand, fixing the third strut 64 by pressing the stop 68 against the grid 1.

the stop block 68 of the guiding device 6 is pressed against the idle grillwork in the spent fuel pool by the hoisting device. Thereby serving to fix the guide 6.

Further, referring to fig. 10, as a specific embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the long rod measuring device 5 includes a long rod 51 formed by connecting two or more connecting rods 511, the adjacent connecting rods 511 are connected by a connecting shaft (not shown in the drawing), in addition, a lifting lug 52 is provided at one end of the long rod 51, the lifting lug 52 can be matched with a spent fuel pool lifting device to lift the long rod 51, so as to provide conditions for subsequent measurement, a detecting head 53 is provided at the other end of the long rod 51, and the detecting head 53 can extend into the guiding mechanism 6 to detect the unevenness of the pool bottom. Preferably, the detection head 53 is formed in an inverted conical shape, so that the detection head 53 can be adapted to the guide portion 6 by forming the inverted conical shape, and the contact area between the detection head 53 and the bottom of the cell is small, thereby realizing more detailed detection.

Further, referring to fig. 11, as a specific embodiment of the method for expanding the spent fuel pool of the megawatt nuclear power plant provided by the present invention, the lifting lug 52 is provided with an opening 520 for accommodating the long rod body 51, the long rod body is provided with a through hole (not shown in the drawing), two side walls of the opening 520 of the lifting lug 52 are provided with first through holes (not shown in the drawing), and a shaft pin 55 penetrating through the through hole is inserted in the first through hole, so that the shaft pin 55 penetrates through the first through hole and the through hole to realize the rotational connection between the lifting lug 52 and the long rod body 51.

Further, referring to fig. 8, as a specific embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the connecting rod 511 is further provided with a wire 54 for fixing the connecting rod 511 to the supporting frame 7, and by arranging the wire 54, when the connecting rods 511 are connected with each other, the wire 54 is fixed to the supporting frame 7, so as to prevent the connecting rod 511 from falling into the pool.

Further, referring to fig. 12, as a specific embodiment of the method for expanding the spent fuel pool of the million kilowatt nuclear power plant provided by the present invention, the support frame 7 further includes a support frame 7 for mounting a connecting rod 511; the support frame 7 includes a support portion 71 for supporting the connection rod 511, and a fixing portion 72 integrated with the support portion 71; the connection rod 511 is provided with a support hanger 56 which is engaged with the support portion 71. Specifically, the support frame 7 is used for supporting the connecting rod 511, so that the long rod body 51 formed by the connecting rod 511 is supported, and the long rod measuring device in the spent fuel pool of the million kilowatt nuclear power plant formed by the long rod body 51 is convenient to use; the fixing portion 72 of the supporting frame 7 is used for fixing with the external environment such as the sidewall of the top of the spent fuel pool, and the supporting portion 71 is directly contacted with the connecting rod 511 and supports the connecting rod 511.

Preferably, the measurement further comprises the following steps:

the long-rod measuring device 5 is hoisted and placed on the support frame 7 using the second hoisting device 12 so as to assemble the adjacent connecting rods 511.

In the invention, the spent fuel pool has certain radiativity, so the spent fuel pool and the workbench are arranged far away, however, the length of a single long rod measuring device 5 can not meet the actual requirement, and therefore, the long rod measuring device 5 needs to be assembled to meet the actual requirement.

Further, referring to fig. 12 and 13, as a specific embodiment of the method for expanding the spent fuel pool of the megawatt nuclear power plant according to the present invention, the supporting portion 71 is provided with a supporting groove 710, and the supporting groove 710 includes an arc portion 7101 and a notch 7102 communicating with the arc portion 7101; the support pendant 56 includes a first support ring 561, and a second support ring 562 that is integral with the first support ring 561; the outer diameter of the first support ring 561 is smaller than the distance between the two ends of the notch 7102, and the outer diameter of the second support ring 562 is larger than the inner diameter of the circular arc portion 7101. Specifically, the process of placing the connection rod 511 on the support portion 71 is: first support ring 561 passes the inside that notch 7102 got into arc portion 7101, the second support ring 562 that is located the top of first support ring 561 this moment is located the top of arc portion 7101, because the external diameter of second support ring 562 is greater than the internal diameter of arc portion 7101, consequently second support ring 562 and the surperficial butt of supporting part 71 and then realize that connecting rod 511 arranges in supporting part 71, the external diameter of first support ring 561 is less than the internal diameter of arc portion 7101 simultaneously, consequently first support ring 561 and rather than integrative stock 51 can rotate supporting part 71 relatively, so that rotation operation of million kilowatt level nuclear power plant fuel pool inner grid stock measuring device.

Further, referring to fig. 14, as an embodiment of the method for expanding the spent fuel pool of the megawatt nuclear power plant provided by the present invention, the fixing portion 72 includes a flat plate 721 connected to the supporting portion 71, and a first vertical plate 722 and a second vertical plate 723 disposed on the same side of the flat plate 721; a gap is formed between the first vertical plate 722 and the second vertical plate 723, the first vertical plate 722 and the second vertical plate 723 are arranged in parallel, the first vertical plate 722 is positioned on one side of the second vertical plate 723, which is far away from the supporting portion 71, and a screw in threaded connection with the first vertical plate 722 is arranged on the first vertical plate 722. Specifically, the fixing means of the fixing portion 72 and the top of the pool wall 8 of the spent fuel pool and other usage environments is: the gap between the first vertical plate 722 and the second vertical plate 723 is used for accommodating the pool wall 8, and the end of the screw is tightly abutted to the pool wall 8 by tightening the screw arranged on the first vertical plate 722, so that the first vertical plate 722 and the second vertical plate 723 are clamped on the pool wall 8. Of course, the gap between the first upright plate 722 and the second upright plate 723 may be hung on the tank wall 8 without tightening the screw.

the long rod measuring device 5 after measurement is placed on the support frame 7 in advance by using the spent fuel pool hoisting device. Thus, by placing the long rod measuring device 5 on the support frame 7, the long rod measuring device 5 is temporarily stored for later use.

Preferably, the high-density grid installation further comprises the following steps:

a hoisting device is used to be connected with the first traction rope 67, the guiding device 6 is hoisted to a certain distance away from the pool bottom, and the guiding device 6 is moved to the next position of the pool bottom; so that the hoisting device is separated from the first hauling rope 67, and the first hauling rope 67 is bound on the guardrail of the hoisting device of the spent fuel pool. By implementing the step, the underwater movement of the guide device 6 is realized, thereby providing conditions for the subsequent detection of the unevenness of the spent fuel pool bottom.

and repeating the cleaning steps to ensure that the guide device 5 is clean, and after the spent fuel pool hoisting device is used for hoisting the long rod measuring device 5, inserting the long rod measuring device into the underwater guide device 6 to complete the measurement of the position below the spent fuel pool.

and after the unevenness is measured, taking the long rod measuring device 5, the guide device 6 and the camera out of the spent pool and storing the spent pool.

leveling the grillwork, adjusting the height of the support leg of the bottom adjusting device according to the flatness, assembling the bottom adjusting device and the high-density grillwork 1 after adjustment, and hoisting the assembled bottom adjusting device and the high-density grillwork into a spent fuel pool.

Preferably, the grid installation step includes the following steps:

hanging the leveled high-density grillwork 2 into a spent fuel pool;

collecting an underwater grillwork image by using an underwater video device, and transmitting the collected image to an operator so that the operator can perform underwater primary positioning on the high-density grillwork 2;

and pushing the high-density grillwork 2 to an underwater installation position for final positioning by a pushing device according to the image information.

In the invention, the underwater framework image is collected through the underwater video device, and the collected image is transmitted to the operator, so that the operator can know the condition of the underwater framework conveniently, and the underwater initial positioning of the high-density framework 2 is guaranteed subsequently; when the high-density framework 2 is placed in a pool from the pool, the framework is pushed by the pushing device, and the final positioning of the high-density framework 2 is realized by positioning rules and positioning blocks (not shown in the drawing) which are pre-arranged on the high-density framework 2. Preferably, in the present invention, the underwater video device is disposed on a high density grid 2 placed in the pond, but the underwater video device may be installed at other positions, which is not limited herein. Preferably, the pushing device is one of an electric, pneumatic or hydraulic pushing device, and is not limited herein.

two adjacent high-density grillworks 2 in the spent fuel pool are connected through a connecting device.

In the present invention, in order to further improve the stability of the high-density grillwork 2, the mounting process of the present invention further comprises a connecting device, which can be used for connecting the two adjacent grillworks, so as to realize the stability of the bottom of the grillwork.

Specifically, referring to fig. 16 and 17, the connecting device includes a connecting member 10, the connecting member 10 includes a connecting plate 101, a first positioning plate 102 and a second positioning plate 103 are respectively disposed at both ends of the connecting plate 101, the connecting member 103 further includes a temporary screw 104 and a final screw 105, the temporary screw 104 is used for detachably mounting the first positioning plate 102 on one of the pair of grid bottom plates 21, the final screw 105 is used for mounting the second positioning plate 103 on the other of the pair of grid bottom plates 2, and the final screw 105 is used to fixedly connect the first positioning plate 102 to one of the pair of grid bottom plates 21 in place of the temporary screw 104, such that the first positioning plate 102 is mounted on the grid bottom plate 21 by the temporary screw 104, the second positioning plate 103 is mounted on the adjacent grid bottom plate 21 by the final screw 105, the first positioning plate 102 and the second positioning plate 103 are connected through the connecting plate 101, so that the connection between two adjacent high-density grillworks 2 is realized, the stability of the high-density grillworks 2 is ensured, the overturning of the high-density grillworks 2 during an earthquake is prevented, in addition, the device has the advantages of simple structure, convenience in installation and low cost, and the safety of spent fuel storage is improved.

Specifically, the above-described connection process is as follows:

positioning and connecting: a temporary screw 104 is adopted to position and connect the first positioning plate 102 and the second bottom plate of the first grillwork on water;

fixedly connecting: after the first positioning plate 102 and the first grid bottom plate are positioned and connected, placing the grid bottom plate into a spent fuel pool, and fixedly connecting the second positioning plate 103 and the second grid bottom plate in the water by using final screws;

and (3) final connection: the final screws 102 are used to replace the temporary screws 104, and the final fixed connection of the first positioning plate 102 and the first grid bottom plate is realized in water.

In the invention, in the connection of the two grid bottom plates, the bottom plate of the high-density grid 2 which needs to be placed in the spent fuel pool firstly becomes the second grid bottom plate, and the bottom plate of the high-density grid 2 which is placed in the spent fuel pool later is called the first grid bottom plate.

In the invention, the first positioning plate 102 and the old grid bottom plate 2 are firstly screwed by the temporary screws 104, so that the first positioning plate 102 and the prior grid bottom plate are positioned in advance, then the second positioning plate 103 and the subsequent grid bottom plate are fixedly connected by the final screws 105, and after the second positioning plate 103 and the first grid bottom plate are fixedly connected, the temporary screws 104 are replaced by the final screws 105, so that the first positioning plate 102 and the second grid bottom plate are finally connected.

In the invention, the high-density grid frame installation step further comprises the following steps:

and taking the pushing device and the positioning block out of the spent fuel pool through the second hoisting device 12, and collecting for later use.

Further, the high-density grid frame installation step further comprises the following steps:

the device is used for taking out the spent fuel assemblies in idle grillwork placed in a loading well or a spent fuel pool, placing the spent fuel assemblies in the high-density grillwork 2 and finally completing the installation of the high-density grillwork 2.

and installing the high-density grillwork 2 in the spent fuel pool according to the position marked by the nameplate. Thus, the observation and recording of workers are guaranteed.

Preferably, in the present invention, the grid vertical detection further includes the following steps:

and (4) carrying out water verticality detection on the leveled high-density grillwork 2 through a plumb bob device.

Specifically, in the process of installing the high-density grillwork 2 in the spent fuel pool, the unevenness data in the spent fuel pool is mapped in advance and recorded, a worker performs corresponding leveling operation at the bottom of the high-density grillwork 2 according to the unevenness data, the bottom of the high-density grillwork 2 is matched with each point in the spent fuel pool through the leveling device, after leveling, the overwater verticality detection is carried out through a plumb device, then the high-density grillwork is slowly transferred into a spent fuel pool through a hoisting tool, so that the high-density grillwork 2 can be stably installed in the rugged spent fuel pool, the aim of keeping the high-density grillwork vertical to the horizontal plane is fulfilled, finally, the underwater verticality detection is carried out on the installed high-density grillwork 2 through a plugging device so as to confirm that the bottom of the high-density grillwork 2 is leveled with the spent fuel pool, thereby ensuring that the fuel assemblies subsequently filled with spent fuel can be safely inserted into the mounting cavities of the high-density grillwork 2 for storage.

Preferably, the step of detecting the grid verticality further comprises the following steps:

and repeatedly inserting the high-density grillwork 2 into the grillwork units of the high-density grillwork through a plugging device to perform a simulation plugging test so as to detect the underwater verticality. Specifically, the aim of leveling between the bottom of the high-density grillwork 2 and a spent fuel pool and keeping the high-density grillwork 2 vertical to a horizontal plane is fulfilled by leveling the high-density grillwork 2 for the second time, and finally, the verticality detection is carried out on the mounted high-density grillwork 2 through a plugging device or a vertical device, so that the leveling between the bottom of the high-density grillwork 2 and the spent fuel pool is confirmed, and the subsequent fuel assembly filled with spent fuel can be safely inserted into a mounting cavity of a new grillwork to be stored.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant is characterized by comprising the following steps of:

dismantling an old framework: moving the spent fuel in the old grillwork into a temporary storage grillwork; radiation measurement, namely performing radiation level measurement on an old grillwork placed in a spent fuel pool to ensure that the old grillwork can be lifted out of the spent fuel pool; selecting a plurality of points to be measured on the old framework at intervals respectively, measuring the equivalent dose rate value of each point to be measured, and marking the position of each point to be measured and the measured value of each point to be measured when the measured value of each point to be measured is greater than a third preset value; then, the old framework placed in the spent fuel pool is lifted out by using the first hoisting device and transported to a designated area by using transportation equipment for storage;

2. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the old framework dismantling step further comprises the following steps:

3. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 1, wherein the temporary storage grid comprises a first grid arranged in a loading well and a second grid arranged at an idle position of the spent fuel pool.

4. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, further comprising a shielding plate, wherein the shielding plate is installed on the old grillwork.

5. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 1, wherein the high-density trellis is composed of a plurality of storage units for storing spent fuel.

6. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 5, wherein each storage unit is made of cadmium material.

7. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 5, wherein the center-to-center distance between adjacent storage units is 280 mm.

8. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein each point to be measured is sequentially and equally spaced along the length direction of the grid unit.

9. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the dismantling of the old grillwork further comprises the following steps:

10. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 9, wherein the dismantling of the old grillwork further comprises the following steps:

and mounting a support assembly at the bottom of the old framework, wherein the support assembly and the turnover plate are positioned at two opposite ends of the old framework, and the transportation equipment enters the workshop in a reversing mode.

11. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the high-density grid installation step further comprises the following steps:

12. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the high-density grid installation step further comprises the following steps:

13. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the high-density grid installation step further comprises the following steps:

14. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 13, wherein the positioning device comprises positioning blocks for longitudinally pre-positioning the high-density grids on the bottom of the spent fuel pool and positioning scales for transversely pre-positioning the high-density grids on the bottom of the spent fuel pool.

15. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the high-density grid installation step further comprises the following steps:

repeating the above cleaning steps to ensure that the guiding device is clean.

16. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 15, wherein the high-density grid installation step further comprises the following steps:

17. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 16, wherein the high-density grid installation step further comprises the following steps:

18. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 17, wherein the high-density grid installation step further comprises the following steps:

19. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 18, wherein the high-density grid installation step further comprises the following steps:

after repeating the steps of claim 15, the spent fuel pool hoisting device is used to hoist the long rod measuring device, and then the long rod measuring device is inserted into the guiding device to complete the measurement of a position under the pool.

20. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 19, wherein the high-density grid installation step further comprises the following steps:

21. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 20, wherein the high-density grid installation step further comprises the following steps:

22. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 21, wherein the high-density grid installation step further comprises the steps of:

hanging the leveled high-density grillwork into the spent fuel pool;

23. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 1, wherein the high-density grid installation further comprises the following steps:

24. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant according to claim 22, wherein the propulsion device comprises an electric, hydraulic or pneumatic propulsion device.

25. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 22, wherein the high-density grid installation step further comprises the steps of:

26. The method for expanding the spent fuel pool of the million kilowatt nuclear power plant as claimed in claim 22, wherein the high-density grid installation step further comprises the steps of:

and taking the pushing device and the positioning block out of the spent fuel pool through a second hoisting device, and collecting for later use, wherein the positioning block is used for longitudinally pre-positioning the high-density grillwork at the bottom of the spent fuel pool.