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US3904048A
Expired / Lapsed
US
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Device for refueling a nuclear reactor having a core comprising a plurality of fuel assemblies
Assignee: ABB Norden Holding AB
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Filing: 1971-09-20
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Granted: 1975-09-09
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Expires: 1991-09-20
Abstract
Abstract A nuclear reactor formed of fuel assemblies each including a plurality of parallel fuel rods arranged in a predetermined fuel rod lattice, which rods are freely extractable and insertable at one end of the fuel assembly, is refueled by extracting from one of the fuel assemblies a number of fuel rods substantially less than the total number of fuel rods and replacing these by inserting new fuel rods into the vacated positions. This is done for a majority of fuel assemblies of the reactor. At the next refueling operation different fuel rods from those previously replaced are removed and replaced. The removal and return of the rods is produced by a tool having a plurality of gripping members capable of engaging shoulders beneath heads formed on the upper ends of the fuel rods. This may be accomplished by providing a tool having a number of gripping members attached to the tool body corresponding to the lattice positions of the fuel rods to be extracted, having gripping members which can be pushed together to grip beneath shoulders on the upper ends of the fuel rods.
Inventors
- 👤 Santen Aart Van
- 👤 Kjell Elofsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:51
CPC Classifications
G; G21; G21C; G21C19/00; G21C19/02; G21C19/10; G21C19/20; G21C19/205; G21C3/00; G21C3/30; G21C3/32; G21C3/326; G21C3/335; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
339 words
In a device for refuelling a nuclear reactor having a core comprising a plurality of fuel assemblies, each of which comprises a multitude of parallel fuel rods arranged in a predetermined lattice, all the fuel rods being freely extractable and insertable at one end of the fuel assembly, a tool for extracting and inserting a number of the freely extractable and insertable fuel rods, comprising: a tool body; a number of gripping members attached to the tool body in positions corresponding to the lattice positions of the fuel rods to be extracted; means for urging the gripping members to grip and to release the fuel rods; the tool body comprising: a transverse and with respect to the fuel rods axially movable carrier member having a multitude of connection points for the gripping members, the connection points being arranged in a predetermined lattice identical to the fuel rod lattice; and guide means attached to the transverse carrier member for guiding the gripping members at least substantially coaxially with the respective fuel rods; the tool having a multitude of said gripping members, of which a number corresponding to the number of fuel rods to be extracted at a given occasion are removably attached to the transverse carrier member at the connection points; each gripping member comprising at least two cooperating gripping jaw members movable into and out of engagement with a shoulder facing the fuel rod at least partially; the grip and release urging means comprising means for moving the gripping jaw members into engagement with the shoulder and means for moving the gripping jaw members out of engagement with the shoulder, whereby the tool can extract and insert an arbitrary number of fuel rods arranged in arbitrary fuel rod positions in the fuel rod lattice of the assembly; the guide means comprising: a plurality of guide rods rigidly attached to the transverse carrier member, each guide rod sliding in a tube parallel with the fuel rods guided by the inner surface of the tube during a fuel rod manipulation operation.
Claim 2
Dependent Claim
339 words
In a device for refuelling a nuclear reactor having a core comprising a plurality of fuel assemblies, each of which comprises a multitude of parallel fuel rods arranged in a predetermined lattice, all the fuel rods being freely extractable and insertable at one end of the fuel assembly, a tool for extracting and inserting a number of the freely extractable and insertable fuel rods, comprising: a tool body; a number of gripping members attached to the tool body in positions corresponding to the lattice positions of the fuel rods to be extracted; means for urging the gripping members to grip and to release the fuel rods; the tool body comprising: a transverse and with respect to the fuel rods axially movable carrier member having a multitude of connection points for the gripping members, the connection points being arranged in a predetermined lattice identical to the fuel rod lattice; and guide means attached to the transverse carrier member for guiding the gripping members at least substantially coaxially with the respective fuel rods; the tool having a multitude of said gripping members, of which a number corresponding to the number of fuel rods to be extracted at a given occasion are removably attached to the transverse carrier member at the connection points; each gripping member comprising at least two cooperating gripping jaw members movable into and out of engagement with a shoulder facing the fuel rod at least partially; the grip and release urging means comprising means for moving the gripping jaw members into engagement with the shoulder and means for moving the gripping jaw members out of engagement with the shoulder, whereby the tool can extract and insert an arbitrary number of fuel rods arranged in arbitrary fuel rod positions in the fuel rod lattice of the assembly; the guide means comprising: a plurality of guide rods rigidly attached to the transverse carrier member, each guide rod sliding in a tube parallel with the fuel rods guided by the inner surface of the tube during a fuel rod manipulation operation.
Claim 3
Dependent Claim
43 words
The tool of claim 1, in which: some of the guide rods are arranged to slide in guide tubes for absorber fingers of a fingertype control rod, the absorber finger guide tubes being placed on fuel rod positions in the fuel rod lattice.
Claim 4
Dependent Claim
47 words
The tool of claim 2, in which the transverse carrier member comprises: a transverse carrier plate; and a tubular, axial shaft having a transverse flange, attached to the transverse carrier plate at at least three of the lattice positions corresponding to guide tubes for the absorber fingers.
Claim 5
Dependent Claim
16 words
The tool of claim 3, in which the connection points are apertures in the carrier plate.
Claim 6
Dependent Claim
59 words
The tool of claim 2, in which each gripping member comprises: a coupling part for detachable coupling to the transverse carrier member; a pivot in the coupling part located in a plane perpendicular to the fuel rods; and two gripping arms, each arm suspended at one end on the pivot and having at the other end a gripping jaw.
Claim 7
Dependent Claim
128 words
The tool of claim 5, in which: the gripping arms are identical, have together substantially circular cross-section, have a narrow pArt and a wide part and a truncated conical transition part between said parts; the means for moving the gripping jaw members out of engagement comprising: a spring element arranged to part the gripping jaws; the means for moving the gripping jaw members into engagement comprising: an axially displaceable transverse locking member having an axial aperture in each lattice position, the apertures located in the fuel rod positions cooperating with the gripping arms so that an axial displacement of the locking member from the narrow part of the gripping arms to the wide part moves together the gripping jaws against the spring force exerted by the spring elements.
Claim 8
Dependent Claim
49 words
The tool of claim 6, in which the transverse locking member comprises a transverse locking plate; an operating rod projecting centrally and axially from the locking plate and through the transverse carrier member; and stops limiting the axial movement of the locking plate with respect to the gripping members.
Claim 9
Dependent Claim
46 words
The tool of claim 7, in which the locking member further comprises: a plurality of axial guide rods attached to the locking plate in absorber finger guide tube positions; the guide rods being slidingly guided by the walls of apertures arranged in the transverse carrier member.
Claim 10
Dependent Claim
32 words
The tool of claim 2, further comprising: at least one axially movable member for preventing the fuel rods from buckling when being inserted into their respective positions in the fuel rod lattice.
Claim 11
Dependent Claim
46 words
The tool of claim 9, in which the buckling-preventing member comprises: an axially movable transverse plate having an axial aperture for each fuel rod, the plate being guided by the guide rods projecting from the transverse carrier member and sliding in the absorber finger guide tubes.
Claim 12
Dependent Claim
48 words
The tool of claim 10, in which the guide rods have radially projecting stops; the buckling-preventing plate during the first part of an insertion operation resting on the radially projecting stops and during the last part of the insertion operation resting at least indirectly against the fuel assembly.
Claim 13
Dependent Claim
106 words
The tool of claim 10, in which the buckling-preventing member further comprises: at least three suspension guide rods attached to the buckling-preventing plate in lattice positions corresponding to those of the absorber finger guide tubes, the suspension guide rods extending axially through and being slidingly guided by apertures in the transverse carrier member and having free ends with radially projecting stops; the buckling-preventing plate during the first part of an insertion operation resting suspended from the transverse carrier member by the suspension guide rods and their stops, and the plate during the last part of an insertion operation resting at least indirectly against the fuel assembly.
Claim 14
Dependent Claim
51 words
The tool of claim 10, further comprising: means for supporting the buckling-preventing plate axially, at least during the first part of the insertion operation, at such a distance along the fuel rods to be inserted into the assembly, that minimum buckling lengths are obtained on both sides of the buckling-preventing plate.
Claim 15
Dependent Claim
49 words
The tool of claim 10, further comprising: an axially movable support frame surrounding the buckling-preventing member radially, at least during the first part of the insertion operation; and axial guide rods attached to the transverse carrier member and arranged outside the fuel assembly for guiding the movable support frame.
References Cited (Backward Citations)
US2863579A
Cited
US3138535A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |