Efficacy of backfilling and other engineered barriers in a radioactive waste repository in salt

Technical Report · Wed Sep 01 04:00:00 EDT 1982

DOI:https://doi.org/10.2172/6743521· OSTI ID:6743521

Claiborne, H C

In the United States, investigation of potential host geologic formations was expanded in 1975 to include hard rocks. Potential groundwater intrusion is leading to very conservative and expensive waste package designs. Recent studies have concluded that incentives for engineered barriers and 1000-year canisters probably do not exist for reasonable breach scenarios. The assumption that multibarriers will significantly increase the safety margin is also questioned. Use of a bentonite backfill for surrounding a canister of exotic materials was developed in Sweden and is being considered in the US. The expectation that bentonite will remain essentially unchanged for hundreds of years for US repository designs may be unrealistic. In addition, thick bentonite backfills will increase the canister surface temperature and add much more water around the canister. The use of desiccant materials, such as CaO or MgO, for backfilling seems to be a better method of protecting the canister. An argument can also be made for not using backfill material in salt repositories since the 30-cm-thick space will provide for hole closure for many years and will promote heat transfer via natural convection. It is concluded that expensive safety systems are being considered for repository designs that do not necessarily increase the safety margin. It is recommended that the safety systems for waste repositories in different geologic media be addressed individually and that cost-benefit analyses be performed.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6743521
• Report Number(s): ORNL/TM-8372; ON: DE83000380
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BACKFILLING
BENTONITE
CLAYS
CORROSION PROTECTION
DESICCANTS
EVALUATION
GEOLOGIC DEPOSITS
MANAGEMENT
PACKAGING
RADIOACTIVE WASTE STORAGE
SALT DEPOSITS
SOLID WASTES
STORAGE
WASTE MANAGEMENT
WASTE STORAGE
WASTES