Updated CLESA PCRSA and ORSA for Sellafield Ltd

The Calder Landfill Extension Segregated Area (CLESA) is an Environmental Permitting Regulations (EPR) authorised Low Activity - Low Level Waste (LA-LLW) containment landfill for the disposal of non-hazardous radioactive waste generated at Sellafield. A team from AECOM and Quintessa have recently worked with Sellafield Ltd to review and update CLESA’s Post-Closure Radiological Safety Assessment (PCRSA) to support ongoing permitting of the facility.

The review was undertaken following the IAEA ISAM methodology, which is a best practice approach for developing a safety assessment for a near-surface disposal facility, to meet the requirements of the Environment Agency’s Guidance on Requirements for Authorisation (GRA) for near-surface disposal facilities for solid radioactive wastes. The review made a number of important updates based on data and scientific developments that post-date the original PCRSA, which was undertaken in 2006. The results demonstrated that the site has sufficient radiological capacity for the current disposal limits to be increased. A number of options were identified for increased disposal limits.

Subsequently, an updated Operational Radiological Safety Assessment (ORSA) was developed. This concluded that the increased disposal limits would not lead to significant doses to CLESA operatives, or significant offsite impacts during the operational phase and subsequent period of institutional control.

The Environment Agency have reviewed the updated PCRSA, and the Sellafield Ltd - contractor team have responded to all the Agency’s questions. As a result, Sellafield Ltd have successfully applied for, and received, a revised permit for CLESA with higher disposal limits. These new limits will allow more of Sellafield’s wastes to be disposed safely to CLESA rather than being transported to other disposal sites. The revised permit will immediately reduce costs, and mitigate schedule risks, for a major decommissioning project.

Image courtesy of Sellafield Ltd.