Thermo-hydraulic analysis in case of gas generation in a disposal facility for vitrified high-level radioactive waste in boom clay

The long-term safety of nuclear waste disposal is an important issue for all countries with a significant nuclear program. Repository disposal in deep geological formations is a promising option for managing high-level radioactive waste. The long term safety of such a repository relies on a multi barrier system, including engineered and natural barriers, which should be evaluated for any anticipated factor that could have negative consequences on their performance. Specifically, assessment of gas generation and transport is a necessary part of a high-level radioactive waste (HLW) geological disposal facility safety assessment. Recent reports dealing with disposal of HLW and spent fuel have confirmed that anaerobic corrosion, which produces H2 gas, will be the main contributor to gas production in the repository near field (Weetjens et al., 2006). In the case of disposal in low permeability plastic clay formations, such as Boom Clay in Belgium, it is important to assess whether gas production rates can exceed the capacity of the near field to store and/or dissipate these gases.