Testing of Novel Application of GOTHIC{sup TM} to Modelling of Hydrogen Distribution in Intermediate Level Waste Storage Facilities - 16499
One of the strategies for treatment of intermediate level waste in the United Kingdom is to retrieve the waste from the legacy storage area, condition in a suitable storage container and then hold on-site in an intermediate level waste store until permanent storage in a geological disposal facility becomes available. During storage, hydrogen may be generated inside the containers at a slow rate by a number of mechanisms. The containers can be equipped with vents that release hydrogen and other gasses into the intermediate level waste store, a building which would be constructed to high standards to minimise ingress of moisture. With the low number of air changes associated with the building design there is the potential for gas to accumulate over time. There is, therefore, a requirement to be able to predict future gas concentrations inside the building over a range of operating conditions to ensure that a safe operating envelope is maintained. The usual approach to this problem is to model the evolution of the hydrogen distribution by use of computational fluid dynamics tools. In a situation where weeks of real time need to be simulated in order to understand the slow build-up of a very small volumetric concentration of hydrogen, the use of computational fluid dynamics is not practicable within the time scales demanded by industry. This paper investigates a new approach to tackling this problem using the thermal hydraulic code GOTHIC{sup TM} (GOTHIC{sup TM} incorporates technology developed for the electric power industry under the sponsorship of EPRI, the Electric Power Research Institute). (authors)