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Title: Post-irradiation examination of capsule P13T

Technical Report ·
DOI:https://doi.org/10.2172/5919321· OSTI ID:5919321

Postirradiation examination revealed excellent performance of the H-451 and TS-1240 graphite bodies and fuel rods irraidated to a peak fluence of 8.0 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGR/ and to a peak volume-average fuel rod temperature of 1215/sup 0/C. A range of fuel rod variables was tested matrix filler graphite, shim particles, compositions; no variable was detrimental to the rod integrity. Particle batches with coating designs representative of the LHTGR (Large HTGR) design requirements exhibited fair irradiation performance to full fast neutron exposure ((8.0 x 10/sup 25/ n/m/sup 2/) (E > 29 fJ)/sub HTGR/) and burnups of 75%. True in-service particle failures were concluded to be <0.3% for all P13T particles. The observed failure was attributed to the outer pyrolytic carbons (OPyC) layer. The failure fraction for 32 P13T fuel rods are greater than predicted, but the mean observed value is less than predicted up to fast fluences of approx. 6.0 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGT/ at 50% confidence. Incipient degradation of the SiC coating due to palladium attack was observed in the HEU UC/sub 2/-TRISO and the UCO (oxygen/uranium ratio (O/U) = 0.64) fuel rods.

Research Organization:
General Atomics, San Diego, CA (United States)
DOE Contract Number:
AT03-76ET35300
OSTI ID:
5919321
Report Number(s):
GA-A-15608; ON: DE82002983
Country of Publication:
United States
Language:
English