Characterization of Cassini GPHS Fueled-Clad Production Girth Welds

Franco-Ferreira, E.A.

Oak Ridge National Laboratory

关键词: Sensitivity;    Y-12 Plant Nesdps Office Of Nuclear Energy Space And Defense Power Systems;    Testing;    Nesdps Office Of Nuclear Energy Space And Defense Power Systems;    Geometry;   

DOI  :  10.2172/814205
RP-ID  :  ORNL/TM-2000/84
RP-ID  :  AC05-00OR22725
RP-ID  :  814205

美国|英语

来源: UNT Digital Library

【 摘 要 】

Fueled clads for radioisotope power systems are produced by encapsulating {sup 238}PuO{sub 2} in iridium alloy cups, which are joined at their equators by gas tungsten arc welding. Cracking problems at the girth weld tie-in area during production of the Galileo/Ulysses GPHS capsules led to the development of a first-generation ultrasonic test for girth weld inspection at the Savannah River Plant. A second-generation test and equipment with significantly improved sensitivity and accuracy were jointly developed by the Oak Ridge Y-12 Plant and Westinghouse Savannah River Company for use during the production of Cassini GPHS capsules by the Los Alamos National Laboratory. The test consisted of Lamb wave ultrasonic scanning of the entire girth weld from each end of the capsule combined with a time-of-flight evaluation to aid in characterizing nonrelevant indications. Tangential radiography was also used as a supplementary test for further evaluation of reflector geometry. Each of the 317 fueled GPHS capsules, which were girth welded for the Cassini Program, was subjected to a series of nondestructive tests that included visual, dimensional, helium leak rate, and ultrasonic testing. Thirty-three capsules were rejected prior to ultrasonic testing. Of the 44 capsules rejected by the standard ultrasonic test, 22 were upgraded to flight quality through supplementary testing for an overall process acceptance rate of 82.6%. No confirmed instances of weld cracking were found.