GB1558595A - Processing of irradiated nuclear fuel elements - Google Patents

Processing of irradiated nuclear fuel elements Download PDF

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Publication number
GB1558595A
GB1558595A GB19160/76A GB1916076A GB1558595A GB 1558595 A GB1558595 A GB 1558595A GB 19160/76 A GB19160/76 A GB 19160/76A GB 1916076 A GB1916076 A GB 1916076A GB 1558595 A GB1558595 A GB 1558595A
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GB
United Kingdom
Prior art keywords
assembly
sub
wrapper
nuclear fuel
cut
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
GB19160/76A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Atomic Energy Authority
Original Assignee
UK Atomic Energy Authority
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 UK Atomic Energy Authority filed Critical UK Atomic Energy Authority
Priority to GB19160/76A priority Critical patent/GB1558595A/en
Publication of GB1558595A publication Critical patent/GB1558595A/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
    • G21C19/34—Apparatus or processes for dismantling nuclear fuel, e.g. before reprocessing ; Apparatus or processes for dismantling strings of spent fuel elements
    • 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

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

Description

(54) IMPROVEMENTS IN OR RELATING TO THE PROCESSING OF IRRADIATED NUCLEAR FUEL ELEMENTS (71) We, UNITED KINGDOM ATOMIC ENERGY AUTHORITY, London, a British Authority, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the reprocessing of irradiated nuclear fuel.
The nuclear fuel material for fast reactors is encosed in a protective metal sheath to form a fuel pin or fuel element. A bundle of such sheathed fuel pins make up a subassembly. The bundle of fuel pins is surrounded by a metal covering which is known in the art as a wrapper and which has end fittings to support the fuel pins and to locate the sub-assembly within the reactor.
In the reprocessing of irradiated nuclear fuel, the protective metal sheath of the fuel pins enclosing the nuclear fuel material has to be opened to allow access to the nuclear fuel material. The present invention seeks to provide a method for removing the wrappers from nuclear fuel sub-assemblies to facilitate the opening of the sheathed fuel pin.
According to the present invention a method for the removal of the wrapper from a nuclear fuel sub-assembly includes the step of controlling the depth of cut of a laser beam to cut through the wrapper leaving the interior assembly of the subassembly intact.
The invention will be illustrated by the following description of a method for the removal of the wrapper from a nuclear fuel sub-assembly. The description is given by way of example only and has reference to the accompanying drawing which is a diagrammatic representation of apparatus for removing the wrapper from a nuclear fuel sub-assembly.
A nuclear fuel sub-assembly 1 is mounted within a shielded cell 2 between two conventional chucks 3 and 4 to enable the sub-assembly to rotate about its longitudinal axis. A lased generator 5 is located outside the cell 2 and the beam emitted by the generator is transmitted into the cell along a stepped guide 6 which prevents the egress of gas and alpha particles from the cell.
The beam entering the cell is reflected by a fixed mirror 7 adjacent to the end of the beam guide 6 within the cell on to a mirror 8 which is mounted on a support 9 which is carried on a screw threaded shaft 10 so that it can traverse the length of the sub-assembly as the shaft 10 is rotated.
The laser beam is preferably transmitted through the beam guide 6 and reflected by the mirrors 7, 8 as a diffuse beam which may be, for example one centimetre in diameter. For effective cutting it is necessary to focus the beam. Conveniently, the focussed beam may have a diameter of about 0.1 mm. The focussing of the beam enables.
a less-powerful laser generator to be used which can be an important economy. The beam should be focussed to provide the minimum depth of focus so as to ensure that only the wrapper is cut and the interior assembly of the sub-assembly is left intact. Because a fuel sub-assembly, particularly an irradiated sub-assembly, may not have a regular profile it is necessary to have a focussing device which controls the focus according to the contours of the subassembly. The focussing device may include a cam follower riding on top of the wrapper and governing the focussing of the beam. Such profile following focussing devices are already known.
The focussing device may comprise a nozzle 11 in the form of a copper cone shaped to concentrate the laser beam and the cutting effect of the laser beam may be assisted by feeding the oxygen into the cone under pressure. In the presence of oxygen the metal to be cut is burned rather than melted and a less powerfull laser is effective. The oxygen can also be directed into the cone so that it serves additionally to keep the cone relatively cool.
The focussing device is mounted on the movable support on which the moving mirror is supported and causes the wrapper to be cut longitudinally as the support traverses the length of the sub-assembly. Lateral cuts of the wrapper are made by rotating the sub-assembly in the chucks whilst keeping the movable support stationary.
The apparatus described above makes only one cut in the wrapper at a time. If a sufficiently powerful laser generator is used it may be possible to utilise beam splitting devices which split the beam emitted by the generator into a number of less powerful beams each of which can be directed onto the sub-assembly by mirrors.
For example, for removing the wrapper from a fuel sub-assembly in which the wrapper is in the form of a hexagonal tube the beam emitted by the generator may be split into six less powerful beams which are focussed and directed at the faces of the wrapper. Simultaneous movement of the focussed beams enables all six faces to be cut at one time. By making a longitudinal cut along one edge of each face and then making lateral cuts across the faces, lengths of wrapper may be removed in six pieces.
In an alternative embodiment the laser beam emitted by the generator may be passed through the cell shielding and may be brought to focus at a toint within the cell whilst the sub-assembly from which the wrapper is to be removed is moved past the focussed beam to effect cutting - of the wrapper.
A particular advantage of the use of a laser beam for cutting the wrappers from sub-assemblies is that the laser generator can be mounted outside the cell in which the radioactive sub-assembly is located thus facilitating maintenance.
WHAT WE CLAIM IS:- 1. A method for the removal of the wrapper from a nuclear fuel sub-assembly including the step of controlling the depth of cut of a laser beam to cut through the wrapper leaving the interior assembly of the sub-assembly intact.
2. A method for the removal of the wrapper from a nuclear fuel sub-assembly as claimed in claim 1 wherein the sub-assembly is mounted between rotatable chucks and the laser beam is directed towards the subassembly by a mirror mounted on a support which traverses the sub-assembly longitudinally.
3. A method for the removal of the wrapper from a nuclear fuel sub-assembly as claimed in claim 1 or claim 2 wherein a laser beam is split into a plurality of lesspowerful beams each of which is directed towards the sub-assembly and each of which is movable relative to the sub-assembly.
4. A method for the removal of the wrapper from a nuclear fuel sub-assembly as substantially as hereinbefore described with reference to the accompanying drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. and a less powerfull laser is effective. The oxygen can also be directed into the cone so that it serves additionally to keep the cone relatively cool. The focussing device is mounted on the movable support on which the moving mirror is supported and causes the wrapper to be cut longitudinally as the support traverses the length of the sub-assembly. Lateral cuts of the wrapper are made by rotating the sub-assembly in the chucks whilst keeping the movable support stationary. The apparatus described above makes only one cut in the wrapper at a time. If a sufficiently powerful laser generator is used it may be possible to utilise beam splitting devices which split the beam emitted by the generator into a number of less powerful beams each of which can be directed onto the sub-assembly by mirrors. For example, for removing the wrapper from a fuel sub-assembly in which the wrapper is in the form of a hexagonal tube the beam emitted by the generator may be split into six less powerful beams which are focussed and directed at the faces of the wrapper. Simultaneous movement of the focussed beams enables all six faces to be cut at one time. By making a longitudinal cut along one edge of each face and then making lateral cuts across the faces, lengths of wrapper may be removed in six pieces. In an alternative embodiment the laser beam emitted by the generator may be passed through the cell shielding and may be brought to focus at a toint within the cell whilst the sub-assembly from which the wrapper is to be removed is moved past the focussed beam to effect cutting - of the wrapper. A particular advantage of the use of a laser beam for cutting the wrappers from sub-assemblies is that the laser generator can be mounted outside the cell in which the radioactive sub-assembly is located thus facilitating maintenance. WHAT WE CLAIM IS:-
1. A method for the removal of the wrapper from a nuclear fuel sub-assembly including the step of controlling the depth of cut of a laser beam to cut through the wrapper leaving the interior assembly of the sub-assembly intact.
2. A method for the removal of the wrapper from a nuclear fuel sub-assembly as claimed in claim 1 wherein the sub-assembly is mounted between rotatable chucks and the laser beam is directed towards the subassembly by a mirror mounted on a support which traverses the sub-assembly longitudinally.
3. A method for the removal of the wrapper from a nuclear fuel sub-assembly as claimed in claim 1 or claim 2 wherein a laser beam is split into a plurality of lesspowerful beams each of which is directed towards the sub-assembly and each of which is movable relative to the sub-assembly.
4. A method for the removal of the wrapper from a nuclear fuel sub-assembly as substantially as hereinbefore described with reference to the accompanying drawing.
GB19160/76A 1977-08-09 1977-08-09 Processing of irradiated nuclear fuel elements Expired GB1558595A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB19160/76A GB1558595A (en) 1977-08-09 1977-08-09 Processing of irradiated nuclear fuel elements

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB19160/76A GB1558595A (en) 1977-08-09 1977-08-09 Processing of irradiated nuclear fuel elements

Publications (1)

Publication Number Publication Date
GB1558595A true GB1558595A (en) 1980-01-09

Family

ID=10124770

Family Applications (1)

Application Number Title Priority Date Filing Date
GB19160/76A Expired GB1558595A (en) 1977-08-09 1977-08-09 Processing of irradiated nuclear fuel elements

Country Status (1)

Country Link
GB (1) GB1558595A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2472250A1 (en) * 1979-12-20 1981-06-26 Nukem Gmbh METHOD AND APPARATUS FOR EXTINGUISHING NUCLEAR COMBUSTIBLE MATERIALS FROM THEIR SOLDERING TUBES
US4317021A (en) * 1980-02-22 1982-02-23 The United States Of America As Represented By The United States Department Of Energy Laser cutting apparatus for nuclear core fuel subassembly
FR2539660A1 (en) * 1983-01-25 1984-07-27 Commissariat Energie Atomique METHOD AND DEVICE FOR CUTTING A WIRE
US4486645A (en) * 1980-07-03 1984-12-04 Armour Food Company Process for removing packaging materials from packaged products
GB2156573A (en) * 1984-03-16 1985-10-09 Kernforschungsanlage Juelich Process and apparatus for separating ceramic nuclear fuels from metallic carriers

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2472250A1 (en) * 1979-12-20 1981-06-26 Nukem Gmbh METHOD AND APPARATUS FOR EXTINGUISHING NUCLEAR COMBUSTIBLE MATERIALS FROM THEIR SOLDERING TUBES
US4317021A (en) * 1980-02-22 1982-02-23 The United States Of America As Represented By The United States Department Of Energy Laser cutting apparatus for nuclear core fuel subassembly
US4486645A (en) * 1980-07-03 1984-12-04 Armour Food Company Process for removing packaging materials from packaged products
FR2539660A1 (en) * 1983-01-25 1984-07-27 Commissariat Energie Atomique METHOD AND DEVICE FOR CUTTING A WIRE
EP0118328A1 (en) * 1983-01-25 1984-09-12 Commissariat A L'energie Atomique Process and appliance for cutting a wire
US4528435A (en) * 1983-01-25 1985-07-09 Commissariat A L'energie Atomique Wire cutting process and apparatus
GB2156573A (en) * 1984-03-16 1985-10-09 Kernforschungsanlage Juelich Process and apparatus for separating ceramic nuclear fuels from metallic carriers

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee
PCPE Delete 'patent ceased' from journal

Free format text: 5066,PAGE 4079

746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19950809