skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Prediction of temperature increases in a salt repository expected from the storage of spent fuel or high-level waste

Technical Report ·
DOI:https://doi.org/10.2172/5129155· OSTI ID:5129155

Comparisons in temperature increases incurred from hypothetical storage of 133 MW of 10-year-old spent fuel (SF) or high-level waste (HLW) in underground salt formations have been made using the HEATING5 computer code. The comparisons are based on far-field homogenized models that cover areas of 65 and 25 sq miles for SF and HLW, respectively, and near-field unit-cell models covering respective areas of 610 ft/sup 2/ and 400 ft/sup 2/. Preliminary comparisons based on heat loads of 150 kW/acre and 3.5 kW/canister indicated near-field temperature increases about 20% higher for the storage of the spent fuel than for the high-level waste. In these comparisons, it was also found that the thermal energy deposited in the salt after 500 years is about twice the energy deposited by the high-level waste. The thermal load in a repository containing 10-year-old spent fuel was thus limited to 60 kW/acre to obtain comparable far-field thermal effects as obtained in a repository containing 10-year-old high-level waste loaded at 150 kW/acre. Detailed far-field and unit-cell comparisons of transient temperature increases have been made based on these loadings. Unit-cell comparisons were made between a canister containing high-level waste with an initial heat production rate of 2.1 kW and a canister containing a PWR spent fuel assembly producing 0.55 kW. Using a three-dimensional unit-cell model, a maximum salt temperature increase of 260/sup 0/F was calculated for the high-level waste prior to back-filling (5 years after burial), whereas a maximum temperature increase of 110/sup 0/F was calculated for the spent fuel prior to backfilling (25 years after burial). Comparisons were also made between various configurational models for the high-level waste showing the applicability of each model.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5129155
Report Number(s):
ORNL/ENG/TM-7; TRN: 78-009559
Country of Publication:
United States
Language:
English