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Title: Summary of WIPP Room B heater test brine and backfill material data

Technical Report ·
OSTI ID:5498076

Simulated DHLW (Defense High Level Waste) package performance tests were carried out at the WIPP (Waste Isolation Pilot Plant) by emplacing a number of waste canisters containing electrical heaters into the floor of the mine. Peak temperatures were about 130{degrees}C, and the tests ran for three years. During this time, an unanticipated large amount of water was collected from heater hole BO42. A study was, therefore, undertaken to determine if this fluid was derived from normal weep brines. This was accomplished by comparing the amount of salt deposited by the dried weep brines with the volume of condensed steam collected during the test. Documenting the post-test condition of the various backfills was the other objective of this report. In spite of being exposed to acidic vapors, the bentonite-sand backfill retained its mineralogic integrity. However, the bentonite-sand backfill compacted between the canister and the wall only achieved a density that was about three quarters that of a pore-free material. The bentonite backfill also showed evidence of hair-line cracks through which steam had left the vicinity of the canister. In contrast, compacted crushed salt backfill exhibited no evidence of through-going cracks and was compacted to better than 99% of that of pure nonporous sodium chloride. Thus, the seal provided by a crushed salt backfill appears to be superior to that provided by bentonite. 13 refs., 6 tabs.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5498076
Report Number(s):
SAND-90-0626; ON: DE91016871
Country of Publication:
United States
Language:
English