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Characterization of Cassini GPHS fueled clad production girth welds.

DE00752977

Publication Date	2000
Personal Author	Franco-Ferreira, E. A.; Moyer, M. W.; Reimus, M. A. H.; Placr, A.; Howard, B. D.
Page Count	55
Abstract	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 GP HS 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.</ AB>
Keywords	Radioisotope Heat Sources Thermoelectric Generators Spacecraft Power Supplies Plutonium 238 Plutonium Oxides Fuel Cans Iridium Alloys Gas Tungsten-arc Welding Crack Propagation Welded Joints Ultrasonic Testing Leak Testing EDB/070000 EDB/300000
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Oak Ridge National Lab., TN (US).; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200025
Contract Number	AC05-00OR22725

Characterization of Cassini GPHS fueled clad production girth welds.

Characterization of Cassini GPHS fueled clad production girth welds.
DE00752977

Publication Date	2000
Personal Author	Franco-Ferreira, E. A.; Moyer, M. W.; Reimus, M. A. H.; Placr, A.; Howard, B. D.
Page Count	55
Abstract	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 GP HS 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.</ AB>
Keywords	Radioisotope Heat Sources Thermoelectric Generators Spacecraft Power Supplies Plutonium 238 Plutonium Oxides Fuel Cans Iridium Alloys Gas Tungsten-arc Welding Crack Propagation Welded Joints Ultrasonic Testing Leak Testing EDB/070000 EDB/300000
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Oak Ridge National Lab., TN (US).; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200025
Contract Number	AC05-00OR22725