WO1998026424A1 - Apparatus for assembling nuclear fuel bundles - Google Patents

Apparatus for assembling nuclear fuel bundles Download PDF

Info

Publication number
WO1998026424A1
WO1998026424A1 PCT/GB1997/003333 GB9703333W WO9826424A1 WO 1998026424 A1 WO1998026424 A1 WO 1998026424A1 GB 9703333 W GB9703333 W GB 9703333W WO 9826424 A1 WO9826424 A1 WO 9826424A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
rod
skeleton
force
puller
Prior art date
Application number
PCT/GB1997/003333
Other languages
French (fr)
Inventor
Paul Hugh Desborough
Original Assignee
British Nuclear Fuels Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Nuclear Fuels Plc filed Critical British Nuclear Fuels Plc
Priority to AU52319/98A priority Critical patent/AU5231998A/en
Publication of WO1998026424A1 publication Critical patent/WO1998026424A1/en

Links

Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
    • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
    • G21C3/334—Assembling, maintenance or repair of the bundles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • This invention relates to apparatus for assembling a nuclear fuel element which comprises a support skeleton of spaced apart grids and a plurality of fuel rods (carrier tubes loaded with pellets) located in the skeleton.
  • a fuel assembly skeleton is loaded into fuel skeleton location equipment.
  • the skeleton is in the form of a plurality of spaced apart grids, each in the form of a matrix of holes or cells which are aligned along the length of the skeleton.
  • a Pressurised Water Reactor makes use of fuel rods which are relatively long and slender, perhaps of the order of 4m in length and 8mm in diameter. A fuel skeleton might hold of the order of 200 fuel rods when fully loaded.
  • a Boiling Water Reactor makes use of fuel rods which are both shorter and of greater diameter than those for a PWR.
  • apparatus for assembling a nuclear fuel element comprising means for inserting a nuclear fuel rod into a fuel skeleton by applying a force to the rod to cause it to move longitudinally into said fuel skeleton and means for limiting the force applied below a predetermined level.
  • the force limiting means includes means for varying said predetermined level during the insertion of the rod. In this way account is taken of the increased resistance to the movement of the rod as it enters more fully into the skeleton, additional resistance to movement being created as a result of the engagement of the rod with the cell walls of successive grids.
  • the force limiting means includes a pneumatic cylinder which is coupled to the fuel rod insertion means and which is pressurised to an extent such that, when the predetermined level is exceeded, the cylinder is actuated to cause the application of the force to be ceased.
  • the pneumatic cylinder is supplied with air from an electronically controlled pressure regulator.
  • the cylinder is arranged so that its actuation causes the operation of a limit switch which is effective to cause cessation of the insertion force.
  • Figures 1A and IB are side and front elevations respectively, showing a fuel element for a Boiling Water Reactor
  • Figures 2A and 2B are side and front elevations showing a fuel element for a Pressurised Water Reactor, located on a fuel skeleton location fixture;
  • Figure 3 is a plan view of the drive system for the arrangement shown in
  • Figures 5A, 5B and 5C are a plan view, a side elevation and a front elevation of rod pulling apparatus
  • Figures 6A, 6B and 6C are a plan view, side elevation and front elevation of fuel rod pushing apparatus;
  • Figure 7 shows a force limiting unit;
  • Figure 8 shows a puller rod collet locking actuator;
  • Figure 9 shows the pusher rod attachment to a pull/push head.
  • Apparatus in accordance with the present invention includes a fuel skeleton which is loaded into fuel skeleton location equipment and clamped into position by means of a yoke at each grid position.
  • Figures 2A and 2B illustrate the arrangement for a fuel element for a Pressurised Water Reactor.
  • the grids 1 are mounted in grid locators 2 which are arranged on a fuel skeleton location fixture 3 mounted on a support which includes a drive system 5.
  • Fuel rods 7 are shown in broken lines in Figure 2A.
  • the arrangement is similar for a fuel element for a Boiling Water Reactor (see Figures 1 A and IB) although there is located between each pair of grids and grid locators a fuel rod guide plate 11.
  • the drive system 5 enables the skeleton to move laterally so that individual grid cells in a given row across the skeleton cross-section can be aligned with the fuel rod and the rod pulling machine axis.
  • the drive system may also be capable of moving the fuel skeleton in the vertical direction so that any grid cell in a particular column in the skeleton cross-section can be aligned with the fuel rod and puller.
  • the fuel assembly skeletons or grids might be loaded into a fixture off line so that the fixture then locates directly onto the drive system. In this way, handling of the fuel skeleton grid set-ups and loaded fuel elements can be modularised into the handling of these fixtures on a trolley or guided vehicle system.
  • the fuel rod to be pulled is placed onto a support at the opposite end of the skeleton location equipment from the puller/pusher equipment shown in Figures 5A to 5C.
  • the bottom end plug of the fuel rod is adjacent to the skeleton location equipment.
  • the identity of the fuel rod is read to a control system using bar code reading equipment.
  • the fuel rod pulling equipment comprises an actuator capable of traversing a distance greater than the length of the longest fuel rod, which is about 4m. Onto this is attached a puller (PWR) / pusher (BWR) head 21.
  • the puller/pusher head couples to a puller rod 23 via a force limiting unit 25.
  • the puller rod includes an outer sleeve which carries a locking rod down its centre. Both sleeve and locking rod are long enough to reach through a fuel element skeleton and attach via a collet 26 to the bottom end plug of a fuel rod.
  • the force limiting unit couples the puller/pusher head 21 to the puller/pusher rod 23 and limits the force which the latter can apply to the fuel rod/grid/skeleton. It is formed from a pneumatic cylinder 29 supplied with air from an electronically controlled pressure regulator. When in the pushing mode, the pneumatic cylinder 29 extends to position the puller rod collet 27 as far from the puller/pusher head 21 as possible. With the correct skeleton grid cell aligned with the fuel rod to be loaded and the fuel rod puller/pusher axis, the puller/pusher actuator advances the puller rod through the skeleton to engage the fuel rod end plug.
  • the force it applies is limited to the air pressure x the area of cross-section of the pneumatic cylinder + friction.
  • the cylinder is pushed off its limit switch (proximity switches are mounted at each end of the cylinder actuator's stroke), a signal is fed to the controlling programmable logic controller and the movement is stopped.
  • the collet After successful threading of puller rod 23 through the skeleton into the fuel rod end plug, the collet is locked by a cylinder 31 driving forward a locking rod.
  • the force limiting pneumatic cylinder 29 then reverses to the opposite end of its stroke ready for the pulling operation.
  • the puller/pusher head then reverses its action to begin pulling the fuel rod into the skeleton. Again, if the set or predetermined force is exceeded, the force limiting cylinder is pulled off its limit switch and the process stopped.
  • the electronically controlled pneumatic regulator steps the pressure to match the normally required pull forces according to the fuel rod axial position in the skeleton.
  • the principles for rod pushing are the same as those for threading the puller rod through the skeleton, coupled with the electronic stepping up of pressure according to the axial position of the fuel rod through the series of grids.
  • the fuel rod to be pushed is placed on supports on the puller/pusher equipment in front of a short steel pusher rod attached to the force limiting unit.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Monitoring And Testing Of Nuclear Reactors (AREA)

Abstract

Apparatus for assembling a nuclear fuel element includes fuel rod insertion means (21) for inserting a nuclear fuel rod into a fuel skeleton by applying a force to the rod to cause it to move longitudinally into said fuel skeleton. Force limiting means limit the force applied below a predetermined level.

Description

APPARATUS FOR ASSEMBLING NUCLEAR FUEL BUNDLES
FIELD OF THE INVENTION
This invention relates to apparatus for assembling a nuclear fuel element which comprises a support skeleton of spaced apart grids and a plurality of fuel rods (carrier tubes loaded with pellets) located in the skeleton.
BACKGROUND OF THE INVENTION
In order to assemble a fuel element, a fuel assembly skeleton is loaded into fuel skeleton location equipment. The skeleton is in the form of a plurality of spaced apart grids, each in the form of a matrix of holes or cells which are aligned along the length of the skeleton. In order to assemble a fuel element, it is necessary to insert fuel rods into the skeleton so that each fuel rod occupies an aligned cell along the length of the skeleton.
The design of a fuel element varies from one type of reactor to another. For instance, a Pressurised Water Reactor (PWR) makes use of fuel rods which are relatively long and slender, perhaps of the order of 4m in length and 8mm in diameter. A fuel skeleton might hold of the order of 200 fuel rods when fully loaded. By way of further example, a Boiling Water Reactor (BWR) makes use of fuel rods which are both shorter and of greater diameter than those for a PWR.
It is normal to assemble a fuel element for a BWR by pushing the fuel rods into the fuel skeleton. However, pushing of the fuel rods into a fuel skeleton for a PWR element is not normally undertaken, because the relatively slender rods tend to buckle and also may cause damage to a fuel skeleton due to consequent misalignment.
For all types of fuel element in which fuel rods are pushed or pulled into fuel skeletons, there is a danger of damage to the rods and the fuel skeletons if undue forces are applied to the rods during assembly. Such forces might arise because of misalignment during the pulling or pushing operation or when threading the puller rod through the skeleton prior to pulling. Such misalignments will result in the fuel rod or puller rod not smoothly passing through the cells from one grid to another. As a result a fuel rod or puller rod may engage a cell wall rather than pass smoothly through the cells and considerable damage may result.
STATEMENTS OF INVENTION
According to the present invention there is provided apparatus for assembling a nuclear fuel element comprising means for inserting a nuclear fuel rod into a fuel skeleton by applying a force to the rod to cause it to move longitudinally into said fuel skeleton and means for limiting the force applied below a predetermined level.
Preferably, the force limiting means includes means for varying said predetermined level during the insertion of the rod. In this way account is taken of the increased resistance to the movement of the rod as it enters more fully into the skeleton, additional resistance to movement being created as a result of the engagement of the rod with the cell walls of successive grids.
Preferably, the force limiting means includes a pneumatic cylinder which is coupled to the fuel rod insertion means and which is pressurised to an extent such that, when the predetermined level is exceeded, the cylinder is actuated to cause the application of the force to be ceased. More preferably, the pneumatic cylinder is supplied with air from an electronically controlled pressure regulator.
Preferably, the cylinder is arranged so that its actuation causes the operation of a limit switch which is effective to cause cessation of the insertion force.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, showing an embodiment of the present invention, by way of example only, there are the following Figures:- Figures 1A and IB are side and front elevations respectively, showing a fuel element for a Boiling Water Reactor; Figures 2A and 2B are side and front elevations showing a fuel element for a Pressurised Water Reactor, located on a fuel skeleton location fixture;
Figure 3 is a plan view of the drive system for the arrangement shown in
Figures 2 A and 2B; Figure 4 shows a fuel rod guide plate;
Figures 5A, 5B and 5C are a plan view, a side elevation and a front elevation of rod pulling apparatus;
Figures 6A, 6B and 6C are a plan view, side elevation and front elevation of fuel rod pushing apparatus; Figure 7 shows a force limiting unit; Figure 8 shows a puller rod collet locking actuator; and Figure 9 shows the pusher rod attachment to a pull/push head.
DESCRIPTION OF THE EMBODIMENT SHOWN IN THE DRAWINGS
Apparatus in accordance with the present invention includes a fuel skeleton which is loaded into fuel skeleton location equipment and clamped into position by means of a yoke at each grid position. Figures 2A and 2B illustrate the arrangement for a fuel element for a Pressurised Water Reactor. The grids 1 are mounted in grid locators 2 which are arranged on a fuel skeleton location fixture 3 mounted on a support which includes a drive system 5. Fuel rods 7 are shown in broken lines in Figure 2A. The arrangement is similar for a fuel element for a Boiling Water Reactor (see Figures 1 A and IB) although there is located between each pair of grids and grid locators a fuel rod guide plate 11.
The drive system 5 enables the skeleton to move laterally so that individual grid cells in a given row across the skeleton cross-section can be aligned with the fuel rod and the rod pulling machine axis. The drive system may also be capable of moving the fuel skeleton in the vertical direction so that any grid cell in a particular column in the skeleton cross-section can be aligned with the fuel rod and puller. The fuel assembly skeletons or grids might be loaded into a fixture off line so that the fixture then locates directly onto the drive system. In this way, handling of the fuel skeleton grid set-ups and loaded fuel elements can be modularised into the handling of these fixtures on a trolley or guided vehicle system.
For fuel rod pulling, the fuel rod to be pulled is placed onto a support at the opposite end of the skeleton location equipment from the puller/pusher equipment shown in Figures 5A to 5C. The bottom end plug of the fuel rod is adjacent to the skeleton location equipment. The identity of the fuel rod is read to a control system using bar code reading equipment.
The fuel rod pulling equipment comprises an actuator capable of traversing a distance greater than the length of the longest fuel rod, which is about 4m. Onto this is attached a puller (PWR) / pusher (BWR) head 21. The puller/pusher head couples to a puller rod 23 via a force limiting unit 25. The puller rod includes an outer sleeve which carries a locking rod down its centre. Both sleeve and locking rod are long enough to reach through a fuel element skeleton and attach via a collet 26 to the bottom end plug of a fuel rod.
The force limiting unit couples the puller/pusher head 21 to the puller/pusher rod 23 and limits the force which the latter can apply to the fuel rod/grid/skeleton. It is formed from a pneumatic cylinder 29 supplied with air from an electronically controlled pressure regulator. When in the pushing mode, the pneumatic cylinder 29 extends to position the puller rod collet 27 as far from the puller/pusher head 21 as possible. With the correct skeleton grid cell aligned with the fuel rod to be loaded and the fuel rod puller/pusher axis, the puller/pusher actuator advances the puller rod through the skeleton to engage the fuel rod end plug. If, in this process, the puller strikes an obstruction, for instance, due to grid cell misalignment, the force it applies is limited to the air pressure x the area of cross-section of the pneumatic cylinder + friction. When this force is exceeded, the cylinder is pushed off its limit switch (proximity switches are mounted at each end of the cylinder actuator's stroke), a signal is fed to the controlling programmable logic controller and the movement is stopped.
After successful threading of puller rod 23 through the skeleton into the fuel rod end plug, the collet is locked by a cylinder 31 driving forward a locking rod. The force limiting pneumatic cylinder 29 then reverses to the opposite end of its stroke ready for the pulling operation. The puller/pusher head then reverses its action to begin pulling the fuel rod into the skeleton. Again, if the set or predetermined force is exceeded, the force limiting cylinder is pulled off its limit switch and the process stopped.
As the fuel rod is pulled through successive grid cells, typically 8 for a Pressurised Water Reactor fuel element, the pull forces accumulate. The electronically controlled pneumatic regulator steps the pressure to match the normally required pull forces according to the fuel rod axial position in the skeleton.
The principles for rod pushing are the same as those for threading the puller rod through the skeleton, coupled with the electronic stepping up of pressure according to the axial position of the fuel rod through the series of grids. The fuel rod to be pushed is placed on supports on the puller/pusher equipment in front of a short steel pusher rod attached to the force limiting unit.

Claims

1. Apparatus for assembling a nuclear fuel element, the apparatus comprising fuel rod insertion means for inserting a nuclear fuel rod into a fuel skeleton by applying a force to the rod to cause it to move longitudinally into said fuel skeleton and force limitating means for limiting the force applied below a predetermined level.
2. Apparatus as in Claim 1 in which the force limiting means includes means for varying said predetermined level during the insertion of the rod.
3. Apparatus as in Claim 1 or Claim 2 in which the force limiting means includes a pneumatic cylinder which is coupled to the fuel rod insertion means and which is pressurised to an extent such that, when the predetermined level is exceeded, the cylinder is actuated to cause the application of the force to be ceased.
4. Apparatus as in Claim 3 in which the pneumatic cylinder is supplied with air from an electronically controlled pressure regulator.
5. Apparatus as in Claim 3 or Claim 4 in which the cylinder is arranged so that its actuation causes the operation of a limit switch which is effective to cause cessation of the insertion force.
PCT/GB1997/003333 1996-12-09 1997-12-03 Apparatus for assembling nuclear fuel bundles WO1998026424A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU52319/98A AU5231998A (en) 1996-12-09 1997-12-03 Apparatus for assembling nuclear fuel bundles

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9625518.7 1996-12-09
GBGB9625518.7A GB9625518D0 (en) 1996-12-09 1996-12-09 Assembly of nuclear fuel elements

Publications (1)

Publication Number Publication Date
WO1998026424A1 true WO1998026424A1 (en) 1998-06-18

Family

ID=10804147

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1997/003333 WO1998026424A1 (en) 1996-12-09 1997-12-03 Apparatus for assembling nuclear fuel bundles

Country Status (3)

Country Link
AU (1) AU5231998A (en)
GB (1) GB9625518D0 (en)
WO (1) WO1998026424A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748713A (en) * 1968-08-19 1973-07-31 Atomic Energy Authority Uk Apparatus for inserting rods into a frame
GB2260848A (en) * 1991-10-24 1993-04-28 Mitsubishi Nuclear Fuel Apparatus for assembling nuclear fuel assembly
US5251243A (en) * 1992-08-21 1993-10-05 Westinghouse Electric Corp. Automatic fuel assembly loader
WO1995006318A1 (en) * 1993-08-20 1995-03-02 Societe Franco-Belge De Fabrication De Combustibles - Fbfc Plant for loading fuel assemblies

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748713A (en) * 1968-08-19 1973-07-31 Atomic Energy Authority Uk Apparatus for inserting rods into a frame
GB2260848A (en) * 1991-10-24 1993-04-28 Mitsubishi Nuclear Fuel Apparatus for assembling nuclear fuel assembly
US5251243A (en) * 1992-08-21 1993-10-05 Westinghouse Electric Corp. Automatic fuel assembly loader
WO1995006318A1 (en) * 1993-08-20 1995-03-02 Societe Franco-Belge De Fabrication De Combustibles - Fbfc Plant for loading fuel assemblies

Also Published As

Publication number Publication date
GB9625518D0 (en) 1997-01-29
AU5231998A (en) 1998-07-03

Similar Documents

Publication Publication Date Title
EP0585052B1 (en) Apparatus for automatic loading of fuel rods in an assembly
US4551299A (en) Multiple fuel rod gripper
US20030202626A1 (en) Smooth collet for pulling fuel rods
EP0017508B1 (en) Leaf spring puller for nuclear fuel rods
KR970003772B1 (en) Nuclear fuel rod loader for pulling fuel rods into a fuel assembly skeleton
US5699393A (en) Fuel assembly loading installation
US4928291A (en) Control cluster provided with removable control elements for a nuclear fuel reactor
WO1998026424A1 (en) Apparatus for assembling nuclear fuel bundles
US5317609A (en) Method and apparatus for installing fuel rods in a nuclear fuel assembly skeleton
FI85071C (en) Device for gripping a bundle of nuclear fuel rods
JPS62116289A (en) End plug for nuclear fuel rod
EP0199043B1 (en) Device for gripping and detaching the top nozzle subassembly from a reconstitutable fuel assembly
KR920000324B1 (en) Vertical close pack rod arrying system
KR100699061B1 (en) Installation for loading fuel rods in a nuclear fuel assembly
US4597934A (en) Multi-function magnetic jack control drive mechanism
CN220272161U (en) Neutron probe installation guiding device of reactor core measuring system
US20090285346A1 (en) Apparatus for assisting the loading or unloading of a core in a pressurized-water reactor
US6229867B1 (en) Spring actuated cable controlled rod for the control rods in a reactor
SE9003330D0 (en) DEVICE FOR REGULATION OF COOL FLOW IN A PRESSURE WATER REACTOR CARTRIDGE CARTRIDGE
EP0200988A1 (en) Rod pulling tool assembly
US4652421A (en) Outer grid strap protruding spring repair apparatus
US4678618A (en) Individual source positioning mechanism for a nuclear reactor fuel assembly
JPH02201193A (en) Degree of reaction reducer for nuclear fuel assembly used
CN219542220U (en) Automatic assembling equipment for cylindrical pins
CN216902271U (en) Control rod assembly guiding device for nuclear power station fuel assembly control rod drawing and inserting force experiment

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZW AM AZ BY KG KZ MD RU TJ TM

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH KE LS MW SD SZ UG ZW AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase