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 CLESA’s Post-Closure Radiological Safety Assessment (PCRSA), to support ongoing permitting of the facility.
Once the volumetric capacity of the site has been used an engineered cap will be installed. A period of institutional control will follow, during which time shorter-lived radionuclides will decay and monitoring will confirm the site is in a safe and passive state. The site licence will be surrendered at the end of the period of institutional control. The post-closure phase begins at this time. The PCRSA explores the potential long-term environmental impacts of the site.
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, on land, for solid radioactive wastes. The review made a number of important updates based on data and scientific developments that post-date the original PCRSA. The results demonstrated that the site has sufficient radiological capacity for the current disposal limits to safely be increased. A number of options were identified for increased disposal limits.
Image courtesy of Sellafield Ltd.