Office for Nuclear Regulation

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NNL Central Laboratory on Sellafield Ltd.’s nuclear licensed site, at Sellafield, Cumbria. A planned compliance inspection covering LC21 (commissioning) and an associated readiness review for the active commissioning of ‘Area 400’ within the Central Laboratory

Executive summary

Purpose of intervention

In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, each year ONR performs a series of planned compliance inspections of core licence conditions targeted at those facilities with the potential to give rise to offsite effects to the public. This core licence condition inspection was performed to assess Sellafield Ltd.’s (SL) compliance with Licence Condition 21 (commissioning) at the Central Laboratory.

The intervention also provided an opportunity to assess the readiness state of National Nuclear Laboratory (NNL) following a request from SL to begin active commissioning of ‘Area 400’ within the Central Laboratory, a facility that is operated by NNL.

Interventions Carried Out by ONR

I undertook the LC21 element of the inspection without additional specialist support, as commissioning falls within my own specialist area (chemical engineering).  To ensure consistency in inspection, I used ONR’s internal guidance NS‑INSP‑GD‑021, revision 3, relating to LC21 inspections.

The readiness inspection was undertaken with the support of several specialist inspectors (mechanical, internal hazards, human factors and control & instrumentation); each following up any relevant findings from their assessments of SL’s submission to ONR regarding the active commissioning of ‘Area 400’ of the Central Laboratory.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not Applicable.  This was not a system-based inspection.

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

During the planned LC21 inspection, my sample finding raised no significant concerns and only a few minor observations/areas for improvement.   These were:

I consider these aspects to be minor as, in my opinion, there is no direct safety implication; the TCAs were clearly labelled and obvious when examining inside the panel (and NNL corrected the issue before the end of the day), the five-day limit for the ‘high priority’ FOBs is somewhat arbitrary (and FOBs were being dealt with as quickly as resource would allow) and finally, following my enquiries, I have no reason to believe that the safety-critical tests were not witnessed contemporaneously by the licensee even though there were small differences in the dates relating to the tester and the witness signatures.

During the readiness inspection, neither I nor the mechanical, internal hazards and control & instrumentation specialist inspectors found issues significant enough to determine that NNL is not ready to progress to active commissioning.  However, the human factors specialist found several shortfalls area that should be completed prior to the transition to active commissioning.  At the time of the inspection, NNL was unable to articulate or provide evidence for a credible programme of work to close out significant shortfalls.  NNL is confident that it will be able to provide such a programme to a timetable that will enable the original permissioning programme dates to be met.

Conclusion of Intervention

Based upon the sampling I have undertaken, I am content that NNL (via the licensee, SL) is applying SL’s arrangements for compliance with LC21 appropriately, with only minor areas for improvement.  On that basis, I am awarding an IIS rating of 3 (adequate).  This is in line with the ONR guidance on IIS ratings:

“…Some opportunities for improvement under ALARP.  Areas for improvement known, but being addressed only slowly.  Site inspector able to identify minor points for improvement.”

The readiness inspection has determined that at the time of the inspection, NNL is not ready to proceed to active commissioning by virtue of the lack of a credible programme to close out remaining shortfalls.  NNL has agreed to provide ONR with a credible programme for close out of the shortfalls.