Method for controlling a nuclear fuel pencil

• US 20050105669A1
• Filed: 02/06/2003
• Published: 05/19/2005
• Est. Priority Date: 02/08/2002
• Status: Abandoned Application

• Current Assignee: Compagnie Generale DES Etablissements Michelin SCA
• Original Assignee: Compagnie Generale DES Etablissements Michelin SCA
• Inventors: Roche, Claude, Pavanello, Fabrice
• Application Number:
  US10/502,874
• Publication Number:
  US 20050105669A1
• Time in Patent Office: Days
• US Class Current: 376/260
• CPC Class Codes: G21C 17/06 Devices or arrangements for monitoring or testing fuel or fuel elements outside the reactor core, e.g. for burn-up, for contamination G21C17/08, G21C17/10 take precedence; detecting leaking fuel elements during reactor operation G21C17/04
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

An electromagnetic induction detector (9) is used to check the weld (6) of a plug (3) to a nuclear fuel cladding (2) still containing a spring (5). A weld made using an excessive energy weakens the metallurgical structure of the spring (5) which may reduce the electromagnetic coupling and the signal recorded by the detector (9). A comparison between the peak values of the signal and the plateau value of the signal gives a criterion for estimating the quality of the fuel rods (1).

Claims

1. Method for the inspection of a nuclear fuel rod (1) with an end plug (3) welded to a cladding (2), a coil spring (5) being compressed between the plug (3) and the fuel (4), using an electromagnetic induction detector (9) along which the rod is moved, by measuring a detector output signal, characterised in that it consists of recording a value of the signal at a base portion (S3), obtained with non-adjacent spring coils, and other values of the signal at peaks (S4 and S5) adjacent to the plateau portion, and which apply maximum magnetic coupling, calculating a ratio

$\frac{\left(\mathrm{S4}-\mathrm{S5}\right)}{\mathrm{S3}}$

of the values of the signal and accepting or rejecting the rod depending on whether the ratio is more than or less than a threshold.