US 6,888,912 B2Granted

Device for positioning and axially aligning a fuel assembly and process and apparatus for restoring a positioning element

AssigneeFramatome ANP GmbH

InventorsGilles Morel, Daniel Grypczynski, Sébastien Joly

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Abstract

The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Claims1

Dependent claims

Device for positioning and axially aligning a fuel assembly (10) in the core (8) of a water-cooled nuclear reactor, consisting of fuel assemblies (10) of straight prismatic shape, each resting, via a lower endpiece (15), on a horizontal support plate (19) of the core, with its axis vertical, and held by an upper core plate (9) resting on an upper endpiece (14) of the fuel assembly (10), comprising, on a respective surface of the core support plate (19) and of the upper core plate (9) directed, respectively, towards the upper endpiece (14) and towards the lower endpiece (15) of the fuel assembly, at least two projecting positioning pins (16, 22) each fixed in an axial direction of alignment of the fuel assembly (10), inside a pin fixing opening (24, 26), to engage respectively in positioning openings for the lower endpiece (15) and the upper endpiece (14) of the fuel assembly (10), characterised in that:

each of the fixing openings for positioning pins (16, 22) in the core support plate (19) and upper core plate (9) comprises a blind threaded bore (24) and a support surface (26a) perpendicular to the axial direction of the fixing opening having at least one dimension greater than a diameter of the threaded blind bore (24), extending around the bore,
each of the positioning pins (16, 22) comprises a threaded shaft (22b) to enable it to be secured by screwing in the threaded bore (24) of the fixing opening and an annular flange (30) having a dimension greater than the diameter of the shaft for bearing on the support surface (26a), and
each of the positioning pins (16, 22) is retained, after screwing and locking in the core support plate (19) or in the upper core plate (9), by a gudgeon (31) engaging in the flange (30) of the positioning pin (16, 22) and in a cavity (32) in the corresponding plate (9, 19) and made inseparable from the positioning pin (16, 22) and the corresponding plate (9, 19).

Dependencies are inferred from the claim text.

Facts

Application: 10/458,732Filed 11 Jun 2003
Priority: FR 02 0716311 Jun 2002
Published: US 2004/0114704 A117 Jun 2004
Granted: 3 May 2005
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G21C 5/06
Details: means for locating or supporting fuel elements
G21C 19/32
Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g.…:…
Y02E 30/30
Energy generation of nuclear origin: nuclear fission reactors
G21C
Nuclear reactors