Office for Nuclear Regulation

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System Based Inspection of the Sellafield Product and Residue Store Containment System

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 sub-division.

In accordance with that strategy, a System Based Inspection (SBI) of the Sellafield Product and Residue Store (SPRS) containment system was planned and undertaken in December 2017. The purpose of this planned inspection was for ONR to examine whether the licensee's safety case in respect of this system has been adequately implemented.

The purpose of this inspection was to determine whether the Safety Systems and Structures (SSS) being inspected are able to fulfil their safety duties (safety functional requirements) adequately, in line with the safety case.

ONR's SBI process examines evidence to determine compliance against six key Licence Conditions (LC). These Licence Conditions (listed below) have been selected because of their importance to nuclear safety and are defined in ONR's process for SBI's

These Licence Conditions (listed below) have been selected in view of their relevance to ensuring nuclear safety and in providing a structured approach to determining whether the safety case has been adequately implemented.

Interventions Carried Out by ONR

I carried out a two day SBI of the Sellafield Product and Residue Store containment system. Sellafield's Nuclear Independent Oversight (NIO) participated in the inspection. The inspection comprised discussions with SL staff, plant walk downs and reviews of plant records and other documentations.

Explanation of Judgement if Safety System Not Judged to be Adequate

I judge the safety case supporting the SPRS containment system to be adequate.

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

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

As part of the scope of this SBI, I have considered if the safety case which is the subject of the inspection might require ONR to assess its 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 assessment.

I identified one shortfall in that the Clearance Certificate does not align with the appropriate implementation and compliance record documents. I have therefore raised a level 4 Regulatory Issue to track SL's corrective action.

Conclusion of Intervention

Based on the evidence sampled during this inspection, I judge that SL has adequately implemented the claims made in its safety case. I therefore consider that inspection ratings of Green (no formal action) are appropriate against LC 10, LC 23, LC24, LC27, LC28 and LC 34 in accordance with ONR assessment rating guidance.