Office for Nuclear Regulation

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Safety system based inspection on ventilation systems and package handling equipment in PMF (N) Store 9 and Store 9 Extension 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.  The inspection plan PP1 for the plutonium finishing and storage facilities (PF&S) details a strategic programme of regulatory inspections which includes a System Based Inspection (SBI) of the Plutonium Management Facility (North) (PMF (N)) Store 9 (S9) and Store 9 extension (S9E) ventilation and containment systems.

S9 and S9E store the product from the plutonium finishing line pending its eventual transfer the central storage facility (SPRS). S9 is currently full and is acting as a static storage space for Special Nuclear Material (SNM) pending transfer to SPRS. S9E is the currently in-use store supporting Magnox fuel reprocessing.

It is anticipated that a large number of package movements will take place within S9E in the near future. The purpose of this planned inspection was to enable the ONR to determine the adequacy of implementation of Sellafield Ltd.’s safety case for the maintenance of safe and secure containment and handling of the SNM.

Interventions Carried Out by ONR

We carried out a two and a half day, on-site team inspection, delivered by the ONR site inspector and two ONR specialist inspectors.  As part of this SBI, we examined SL’s compliance against ONR guidance for the following licence conditions (LCs):

The inspection included a general discussion of the requirements set out for the system in the facility safety case, examination of relevant safety documentation, a plant walk down and individual discussions with relevant plant safety case and operational personnel.

Explanation of Judgement if Safety System Not Judged to be Adequate

The overall safety system was judged to be adequate. However, there was evidence of specific procedural and safety case weaknesses that will be addressed as regulatory issues recorded on the ONR regulatory issues database.

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

The key findings of the inspection are:

Conclusion of Intervention

From our findings, it is our opinion that the ventilation systems and package handling equipment in PMF (N) Store 9 and Store 9 Extension for controlling the risks of leakage and escape of nuclear material met the requirements specified for them in the safety case.

The inspection, however, revealed a few specific issues where safety case compliance was considered to be below an adequate standard. Sellafield Ltd was informed of this at the close out meeting. These issues will be raised as regulatory issues and addressed by ONR specialist inspectors. We do not consider any of these issues represent a serious or immediate risk to nuclear safety.