- Site: Sellafield
- IR number: 21-175
- Date: February 2022
- LC numbers: 10, 23, 24, 27, 28, 34
Executive summary
Purpose of Intervention
The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee, Sellafield Ltd, against a strategy defined by the ONR Sellafield, Decommissioning, Fuel and Waste Division. In accordance with that strategy, a System Based Inspection (SBI) was carried out on the Redundant Settling Tanks (RST) and Effluent Distribution Tanks (EDT) essential services (steam, electrical, air, water supplies).
The purpose of this inspection was for ONR to examine whether the licensee’s safety case claims in respect to RST and EDT essential services have been adequately implemented. The inspection comprised discussions with Sellafield Ltd staff, a targeted plant walkdown and a review of plant records and other documentation.
Interventions Carried Out by ONR
ONR’s SBI process examines evidence to determine compliance against six licence conditions (LC). These LC’s, listed below, have been selected in view of their relevance to ensuring nuclear safety and provide a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.
LC 10 requires Sellafield Ltd to make and implement adequate arrangements for suitable training for all those on site who have responsibility for any operations which may affect safety.
LC23 requires Sellafield Ltd to produce an adequate safety case to demonstrate the safety of its operations, and to identify the conditions and limits necessary in the interests of safety.
LC24 requires Sellafield Ltd to ensure that all operations which may affect safety are carried out in accordance with written instructions.
LC27 requires Sellafield Ltd to ensure that a plant is not operated, inspected, maintained or tested unless suitable safety mechanisms, devices and circuits are properly connected and in good working order.
LC28 requires Sellafield Ltd to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.
LC34 requires Sellafield Ltd to ensure, so far as is reasonably practicable, that radioactive material and radioactive waste on the site is at all times adequately controlled or contained so that it cannot leak or otherwise escape from such control or containment.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
Explanation of Judgement if Safety System Not Judged to be Adequate
The licensee has demonstrated that the Structures, Systems and Components (SSCs) which have been inspected as part of the EDT and RST essential services systems meet the requirements of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Based on the evidence sampled during this inspection, I judge that both RST and EDT have adequately implemented those safety case claims that relate to the essential services system. I consider in respect of LCs 10, 23, 24, 27, 28 and 34 noting the ONR guidance on inspection ratings, that an inspection rating of Green (no formal action required) is merited here.
Conclusion of Intervention
I consider that the licensee has a good knowledge of the physical condition of the essential services, systems and components reviewed during this inspection. Overall, on balance, I consider the safety case supporting the essential services systems to be adequately implemented.