RU2729599C1 - Capsule for transportation and storage of used absorbing rods of control and protection system - Google Patents

Abstract

FIELD: nuclear energy.SUBSTANCE: capsule for further transportation and / or long-term storage of spent absorbing rods of control and protection system (CPS AR), in which CPS AR in amount of up to three pieces are arranged vertically so that axes of absorbing elements (AE) are parallel to axis of capsule. CPS AR are arranged with turning angle in plane perpendicular to axis AE. Inside the capsule case there is a retainer with coaxial shells of larger and smaller diameter. First CPS AR has, as a supporting surface, lower planes of CPS AR head ribs connecting the central part of the head with AE of external radius. Second and third CPS AR in vertical plane are supported by central part of head on previous CPS AR. In the plane perpendicular to axis AE, vertically arranged plates are used in structure of stop. Each CPS AR is fixed by contact of the AE entering it with the side surfaces of the plates, and the arrangement of the plates is selected so that each CPS AR is fixed against rotation in both of the two directions.EFFECT: invention provides maximum use of the useful volume of the capsule for storage of spent CPS AR.1 cl, 6 dwg

Description

The invention relates to the field of nuclear energy, namely, the design of the capsule is proposed, into which the spent absorbing rods of the control and protection system (CPS PS) of the VVER-1000, VVER-1200 reactors are loaded for transportation and / or long-term storage (hereinafter referred to as "capsule ").

CPS PS is a structure of a head and absorbing elements (PEL) fixed in it (patent RU 2473991, 07.12.2011, G21C 3/32, G21C 7/08, publ. 27.01.2013 Bull. No. 3). PEL are made in the form of smooth pipes filled with absorbing material. PEL are suspended on a special head and are spring-loaded. The PS CPS head is a sleeve with cantilever ribs, in which holes are made for PEL installation.

According to the concept of radioactive waste management of the State Corporation "Rosatom", one of the main strategic directions is the creation of a reliable system of long-term controlled storage of radioactive waste (RW). The optimal storage conditions for radioactive waste should ensure safe storage conditions for up to 60 years.

At present, the spent CPS substations together with the spent fuel assemblies (SFAs) of nuclear reactors after decommissioning are placed in the spent fuel pool of the reactor compartment of the NPP. Then the spent fuel assemblies with the spent CPS substations are sent to the spent nuclear fuel (SNF) storage facility for long-term storage and subsequent reprocessing. Due to the specifics of spent fuel assemblies and CPS substations, their safe storage is required under specially provided conditions.

At present, ampoules similar in purpose are known for accommodating spent fuel assemblies of nuclear reactors:

- a method of loading a spent fuel assembly of a nuclear reactor into an ampoule and an ampoule for the implementation of this method (application for invention RU 2006129048, 10.08.2006, G21F 7/00, G21F 5/008, publ. 2008.02.20 Bull. No. 5),

- an ampoule for a spent fuel assembly (patent RU 2353010, 19.03.2008, G21F 5/008, publ. 20.04.2009 Bull. No. 11).

Ampoules with fuel assemblies are placed in a container (case) for transportation and long-term dry storage:

- a sealed canister for storing spent nuclear fuel (patent RU 2372678, 31.10.2008, G21F 5/008, publ. 10.11.2009 Bull. No. 31)

- a sealed container for storing ampoules with bundles of spent fuel elements (patent RU 2500045, 06/04/2012, G21F 5/008, G21C 19/06, publ. 11/27/2013 Bull. No. 33)

There are also known other devices for storing and transporting spent fuel assemblies:

- cover for placement and storage of spent fuel assemblies from VVER-1000 reactors (patent RU 2331943, 10.24.2016, G21F 5/00, G21C 19/06, published 20.08.2008 Bull. No. 23), the cover is used for placement and storage spent fuel assemblies from VVER-1000 reactors. Storage case capacity - 18 pcs. SFA.

- a cover for placement and storage of spent fuel assemblies from the VVER-1000 reactor "(patent RU 2593388, 04.08.2015, G21F 5/00, publ. 08.10.2016 Bull. No. 22).

However, as shown by patent research, at the time of the search, specialized devices for accommodating spent CPS substations were not found in published patent materials. Thus, the claimed invention has no known analogues.

The technical objective of the invention is to develop a capsule design for spent CPS substations, for their transportation and long-term storage, which will ensure the maximum use of the useful volume of the capsule for storing spent CPS substations and maximum use of the usable volume of the spent nuclear fuel storage while ensuring reliable installation of the CPS substations inside the capsule and keeping them reliable. fixation in the capsule for at least 60 years, the possibility of revision and examination of the capsule, as well as minimal costs for the manufacture of the capsule itself. To protect personnel from radiation during transportation, the capsule with spent CPS substations can be placed inside a container with biological shielding.

As a solution to the problem, allowing to achieve the effect with the specified technical characteristics, a design solution is proposed - a capsule for transportation and storage of spent CPS PSs in a special dry-type storage facility with the possibility of removing the capsule from the storage for revision and examination during the entire storage period (at least 60 years ).

The essence of the invention: a capsule intended for placement and storage of the CPS PS in a vertical position in an amount of no more than three. The capsule consists of a body with a stop located inside it for installing the CPS PS and a removable cover. The body has a cylindrical shell, a head in the upper part of the body for installing a removable cover, a support at the bottom for installing the capsule vertically. The removable capsule cover is equipped with a load gripper. PS CPS are installed into the capsule from above with the removable cover open. After loading the CPS PS inside the capsule, a removable cover is installed on it. CPS PS are placed in the capsule in the position in which the PEL axes are parallel to the body axis. A stop is fixed inside the capsule body, on which the first CPS PS is installed. The stop fixes the first control rod of the CPS in two directions: in the vertical plane from falling, so that the PEL does not touch the bottom of the housing support, and also from rotation and displacement in the plane perpendicular to the PEL axis. The stop design contains elements for solving these two problems. To hold it in the vertical plane, the first CPS PS rests on the stop by the lower planes of the CPS PS head ribs, connecting the central part of the head with the PEL of the outer radius. To solve the problem of fixation against rotation and displacement in a plane perpendicular to the PEL axis, vertically arranged plates are used in the design of the stop. The plates are located in the gaps formed between adjacent PELs of three CPS PSs when all of them are loaded into the capsule. The thickness of the plates is not more than the gap between adjacent PEL. The side surfaces of the plates are in contact with the PEL. The plates prevent rotation or displacement of the PEL, and through the PEL and the entire CPS PS. The contact of the side surface of one plate with the PEL provides fixation of the CPS PS against rotation in one direction. To fix the control rod of the CPS from turning in two directions, it is necessary to contact the PEL with the side surfaces of the two plates. In this case, either one PEL belonging to one CPS turns out to be between two plates, or two PELs belonging to the same CPS PS contact two surfaces belonging to different plates. The location of the plates is selected so that each contact provides fixation against rotation of the CPS PS in one of two directions. The plates also prevent displacement of the CPS PS in the plane perpendicular to the PEL axis.

The second and third control rods are supported by the central part of the head on the previously installed control rods. When installed in the capsule, the CPSs are installed with a rotation angle of 20 ° relative to each other in the plane perpendicular to the PEL axis. The second and third PS of the CPS, similarly to the first, are fixed by two lateral surfaces of the plates against rotation in both directions or displacement in the plane perpendicular to the PEL axis. For each control rod, the stop has its own pair of surfaces belonging to two different plates, that is, to fix the second and third control rod, two plates are also required. In this case, one plate, located between the PEL belonging to different CPS, can fix two CPS PSs, for each in one of the directions. For fixing three CPS PSs, the minimum required number of plates is three. To improve the rigidity of the stop, as well as for additional fixation of the CPS PS, the number of vertical plates entering the stop can be increased.

The proposed capsule design is illustrated by the drawings shown in FIG. 1-6:

fig. 1 - General view of the capsule;

fig. 2 is a section of a capsule with an installed stop;

fig. 3 - general view of the stop;

fig. 4 - capsule with loaded CPS substations;

fig. 5 - section А-А, placement of PEL PS CPS in the cylindrical shell of the capsule;

fig. 6 - PS CPS.

The capsule consists of a body, which is a cylindrical shell 1, to which the head 2 is connected in the upper part, into which the cover 3 is installed, and in the lower part of the shell 1 there is a support ring 4 for placing the capsule in a vertical position (Fig. 1). The construction in FIG. 1 is welded. The capsule cover 3 is equipped with a load-gripping element made in the form of a central fungus 5. The closed capsule is installed in the radioactive waste storage cell and the closed capsule is moved behind the central fungus 5 of the cover 3. For orientation of the capsule, including relative to the container with biological shielding in the support ring 4 grooves 6 are made, which include the guides of the container for transporting the capsule with the spent CPS PS.

The capsule lid 3 has latches 7, which are closed when the lid 3 is lowered onto the head 2 (Fig. 2). A stop 8 is fixed inside the capsule. The stop 8 is attached with pins 9 to the cylindrical shell 1. A general view of the stop 8 is shown in FIG. 3. The design of the stop 8 in FIG. 3 is welded. The stop 8 is a structure consisting of plates 10 fastening two coaxial cylindrical shells; larger diameter - the outer shell of the stop 11 and the smaller diameter - the inner shell of the stop 12. The outer shell of the stop 11 enters the cylindrical shell 1 of the body (Fig. 2). To fix the CPS PS from rotation and displacement in the plane perpendicular to the PEL axis, vertical plates 10 of the stop 8 are used. In the particular case of the implementation, the number of plates in the stop is four. Each PS of the CPS 13 is fixed by ensuring the contact of the PEL included in it with the side surfaces of the plates 10 (Fig. 5). At least two PELs belonging to one CPS PS contact two surfaces belonging to different plates. The arrangement of the plates is chosen so that the contact of the plates with the PEL ensures the fixation of each CPS PS against rotation in each of the two directions. The plates also prevent displacement of the CPS PS in the plane perpendicular to the PEL axis.

The thickness of each of the plates 10 is not more than the gap formed between adjacent PELs of three CPS PSs in the case when they are all loaded into the capsule. The head 2 and the support ring 4 have holes 14, 15, respectively, for draining the water in the case of loading the CPS PS into the capsule from the holding pool. The capsule is designed to store a maximum of three CPS PSs.

The CPS PS are installed into the capsule from above with the cover open 3. The first CPS PS rests on the surface B1 of the stop 8 (Fig. 3) with the lower planes of the CPS PS head ribs connecting the central part of the head with the PEL of the outer radius (surface B in Fig. 6). The second and third control rods are supported by the central part of the head (surface B in Fig. 6) on the previously installed control rods. When installed in the capsule, the CPSs are installed with a rotation angle of 20 ° relative to each other in the plane perpendicular to the PEL axis. The stop 8 is installed at a distance from the upper end of the cylindrical shell 1 sufficient to accommodate three CPS PSs.

Claims (1)

A capsule for transportation and / or storage of spent absorbing rods of a control and protection system (CPS), in which up to three CPS PSs are placed vertically inside the capsule so that the axes of absorbing elements (PEL) are parallel to the capsule axis, while the CPS PS are placed with an angle of rotation in a plane perpendicular to the PEL axis relative to each other, which provides a gap between adjacent PELs belonging to different CPS PSs; a stop is fixed inside the capsule body, containing coaxial shells of larger and smaller diameters and vertical plates connecting them, while the shell of a larger diameter secures the stop in the capsule body, the stop ensures fixation of all CPS PSs in the vertical plane from falling and from turning or displacement in the plane, perpendicular to the PEL axis, while the first CPS PS for fixation in the vertical plane has as a supporting surface the lower planes of the ribs of the CPS PS head, connecting the central part of the head with the PEL of the outer radius and perpendicular to the PEL axes, and is installed on a shell of a smaller stop diameter, and the second and the third CPS PS for fixation against falling in the vertical plane is supported by the central part of the head on the previous CPS PS, while for fixing against rotation and displacement of the CPS PS in the plane perpendicular to the PEL axis, the stop design uses vertically arranged plates separating the inner space of the capsule, thickness plates not more than the gap formed between adjacent PELs of three CPS PSs in the case when they are all loaded into the capsule, so that the plates enter the gap between the PELs, while each CPS PS is fixed due to the contact of the PEL entering it with the side surfaces of the plates, and the arrangement of the plates is selected so that each control rod of the control rod is secured against turning in both of the two directions, while fixing one control rod against turning in two directions requires contact of the PEL entering it with the side surfaces of at least two plates, and the minimum number of plates for fixing of all three PS CPS is equal to three.

Images