Office for Nuclear Regulation

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System Based Inspection (SBI) of the Solid Waste Operating Unit containment system, on Sellafield Ltd.’s nuclear licensed site at Sellafield, Cumbria

Executive summary

Purpose of intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee (Sellafield Limited (SL)) against a strategy defined by the ONR Sellafield Programme. 

In accordance with that Strategy, a system based inspection (SBI) of the Solid Waste Operating Unit containment system was planned for February 2016.  The purpose of this planned inspection was for ONR to confirm the adequacy of implementation of the licensee’s safety case claims in respect of this system.

As part of our SBIs, ONR examines evidence of the adequate implementation of six pre-defined licence conditions.  These licence conditions (listed below) have been selected because of their importance to nuclear safety and are defined within ONR’s formal process for SBIs.

Interventions Carried Out by ONR

I led a two-day, on-site SBI of the Solid Waste Operating Unit containment system.  I was supported by mechanical and civil engineering technical support contractors together with a colleague site inspector from the Sellafield Programme.  The inspection comprised discussions with SL staff, plant walk downs and reviews of plant records and other documentation.

Explanation of Judgement if Safety System Not Judged to be Adequate

The containment system was judged to be adequate.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

From the evidence made available to me during this inspection, I consider that SL has adequately implemented those claims within the facility safety case that relate to the containment system.

As part of the scope of this SBI, I have considered if the safety case that is the subject of this inspection might require an ONR assessment of adequacy in a timeframe shorter than otherwise planned.  Based on the information gathered during this SBI, I have no reason to recommend an early assessment of the safety case for this system.

I made a small number of regulatory observations, all of which were accepted by SL and the majority of which will be completed during routine document revision.  There were no regulatory findings generated during this inspection and it is my opinion that a rating of 3 (adequate) is merited for LCs 10, 23, 24, 27, 28 and 34.

Conclusion of Intervention

From the evidence sampled during this inspection, I judge that the licensee has adequately implemented the relevant claims within its safety case, and that there was evidence that the formal arrangements for all the licence conditions against which I inspected are also being implemented adequately.