Microbial aspects of gas generation from low level radioactive waste simulant

Whilst much of the organic matter present in Low Level Radioactive Waste (LLW) resembles that in domestic refuse, the disposal procedure in well engineered sealed repositories is sufficiently different to raise questions as to whether the degradation process will follow the classically accepted sequence from aerobic and anaerobic hydrolysis via anaerobic fermentation to methanogenesis. The generation of large volumes of gas could have significant effects on both the structural integrity of a nuclear waste repository and the rate at which dissolved radionuclides are released into the far field and geosphere. This report summarises the results from a series of experiments which investigate the effects of a range of environmental parameters on the kinetics of methanogenesis in a LLW simulant. The objective of the work was to investigate the effects of specific chemical and physical factors on the potential for gas generation. (author)