Executive summary
Date(s) of inspection:
Aim of inspection
All Licensees have a duty to comply with the Ionising Radiations Regulations 2017 (IRR17). Regulation 12(3) introduces a new duty on employers to estimate doses to members of the public, in addition to the duty to restrict exposures under Regulation 9.
Inspect LLWR’s arrangements for measuring radiation dose and controlling radiation doses to the public so far as is reasonably practicable.
Subject(s) of inspection
Key findings, inspector's opinions and reasons for judgement made
ONR undertook this inspection to examine Low Level Waste Repository’s (LLWR) physical arrangements for controlling exposure to ionising radiations from the LLWR Licensed site to members of the public.
This was one of two planned direct shine and other pathways inspections during 2023-24 in support of the Office for Nuclear Regulation Decommissioning Fuel and Waste sub-division strategy.
The LLWR nuclear licensed site was selected for inspection for the following reasons:-
- The last inspection of LLWR was undertaken in January 2015 (CM9 2015/80201).
- LLWR is one of four licensed sites which has a radiation dose rate to the most exposed member of the public above the ONR Safety Assessment Principle (SAP) Target 3 Basic Safety Objective (BSO) of 0.020 mSv.
- From 2020 to 2022 there has been an upward increase in radiation dose rate to the most exposed member of the public.
The inspection was conducted via discussions with key licensee personnel, the sampling of licensee documentation and a site perimeter fence walk-down. The conclusion of the inspection was that I was content that LLWR had taken adequate steps to reduce doses to the public from the site waste operations.
Conclusion
I noted that number and location of the TLDs in relation to properties outside the site perimeter fence to be adequate.
The number of waste containers being received by the site has reduced by one order of magnitude, reducing the number of on-site transportation doses from the site.
LLWR have placed adequate mobile concrete shielding between the Vault 8 and the site perimeter fence to reduce doses to members of the public off-site.
I noted the reduced stack height of the containers edge of Vault 8, which would reduce the dose rate from those containers to the boundary fence.
I judged LLWR implementation of IRR17 regulation 12 (3) arrangements to be adequate to reduce doses to the public from the site waste operations in the areas inspected and I assign a rating of green.
Feedback was provided to the site at the end of the inspection noting the areas of good practice and areas for improvements specifically:
- The placement of additional TLDs at the perimeter fence location DTLD01 to obtain a more balanced background radiation record of the area.
- The placement of a number of mobile concrete panels between Vault 8 and the perimeter fence to reduce the dose rate to the members of the public.
- Reassessing a proportionate radiation background dose rate to use, which may reduce the maximum dose received to the most exposed member of the public to below the ONR Safety Assessment Principle (SAP) Basic Safety Objective (BSO) of 0.020 mSv.