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Title: Capsule HRB-15A postirradiation examination report

Technical Report ·
OSTI ID:6694664

Capsule HRB-15A successfully irradiated a variety of LHTGR fuel particle types to peak exposures of 6.5 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGR/ fast fluence, 29% FIMA fissile burnup and 6.4% FIMA fertile burnup, and a time-average irradiation temperature of 1100/sup 0/C. The capsule was irradiated in HFIR for 6 months. The HRB-15A fuel rods were in excellent condition following irradiation. Candidate TRISO-coated LEU UC/UO/sub 2/ fuel particles performed adequately for the HTGR steam cycle application. The SiC coatings on the two UC/sub 0/ /sub 5/O/sub 1/ /sub 5/ TRISO batches were least retentive of Ag-110m during irradiation. Severe degradation of the SiC layers by fission product attack had occurred in 70% of these particles with much deeper penetration than in other TRISO batches. Large diameter (nominal 600 ..mu..m kernel) ThO/sub 2/ particles were judged unacceptable for use in an all-TRISO separable fuel system because of high OPyC and SiC failure levels. ZrC barrier layers in two ZrC-TRISO-coated fissile particle batches showed superior resistance to fission products relative to SiC. However, one of the ZrC-TRISO batches was poorly retentive of Ag and Eu, and fuel rods containing both batches had the highest end-of-life fission gas release values. Performance models for defective particles were shown to be overly conservative. Failure rate of OPyC coatings on TRISO particles was found to increase with the particle diameter.

Research Organization:
GA Technologies, Inc., San Diego, CA (USA); Oak Ridge National Lab., TN (USA)
DOE Contract Number:
AT03-84SF11962
OSTI ID:
6694664
Report Number(s):
GA-A-16758; ON: DE84015924
Resource Relation:
Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English