Safety Case for Repository
Environmental Safety Case for Low Level Waste Repository
Serco Energy provided support to the UK Low Level Waste Repository (LLWR) near Drigg, Cumbria, in the production of its 2011 Environmental Safety Case (ESC). Under UK legislation developers or operators of proposed or existing facilities for the disposal of nuclear waste must apply for an Authorisation (Permit) from the Environment Agency, Northern Ireland Environment Agency or Scottish Environment Protection Agency. The Guidance on Requirements for Authorisation expect the developer or operator to produce an ESC, defined as a set of claims concerning the environmental safety of disposals of solid radioactive waste, substantiated by a structured collection of arguments and evidence.
The GoldSim code was used to undertake a number of assessments in support of the ESC. These assessments included consideration of both radiological and non-radiological hazards, and two possible designs for the future vaults at the LLWR were considered. The assessment model included a detailed representation of the contaminant release and flows within the near field, and also implemented a sophisticated approach to the assessment of risks due to abstraction of water from a well. A series of deterministic calculations were undertaken, and also a probabilistic calculation. Two future evolution scenarios were considered. The base case scenario considered coastal erosion such that the coastline would reach the LLWR within around 1,000 years after present, and a variant considered the case where coastal erosion is delayed.