Office for Nuclear Regulation

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LC27, 28 inspection

Executive summary

Purpose of intervention

In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, ONR performs a series of core licence compliance inspections each year with all other licence conditions being assessed at a site over a 5 year period. This core inspection was performed to assess Sellafield Ltd’s (SL’s) compliance with Licence Condition 27 Safety mechanisms, devices and circuits and Licence Condition 28 Examination, inspection, maintenance and testing

Interventions Carried Out by ONR

I carried out a one day Licence Compliance inspection primarily focussed on a review of several Incident Event Reports (IERs) which had been raised by Sellafield Ltd. associated with Safety Mechanism maintenance. In addition I observed a shift Criticality Assembly Area (CAA) Emergency exercise within THORP.

 I also held several information sharing sessions to discuss progress being made with on-going regulatory issues, and preparations for future inspections.

Explanation of Judgement if Safety System Not Judged to be Adequate

N/A as this was not a safety systems inspection.

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

Overall, I considered that in THORP a suitable process to control the release of safety mechanisms for maintenance had generally been adequately implemented.

From my review of two events within THORP regarding the maintenance of safety mechanisms, it was my opinion that the events appeared to reflect deficiencies with THORP’s procedural use and their adherence and their compliance with the expectations of normal standards for disciplined operations, as already captured in an existing ONR Regulatory Issue, rather than fundamental flaws in the processes for controlling maintenance and ensuring the availability of safety mechanisms.

It was my opinion that the visibility of tracking of unavailable safety mechanisms and safety related equipment should be improved, this is also already captured by an extant Regulatory Issue.

From my observations, it was my opinion that THORP demonstrated significant improvement in the performance of its Criticality Assembly Area (CAA) particularly:

 Command and control of the CAA was clear and simulated irradiated and un-irradiated personnel were effectively controlled and appropriately dealt with.

The processing of simulated contaminated persons was much improved and generally well controlled.

I held discussions with the head of THORP regarding ONR’s concerns over the standards of conduct of operations and procedural use and adherence. I was reassured that the head of THORP was taking the issues very seriously, which was evidenced by the approach he had taken to recent instances where performance had fallen short of required standards.

Conclusion of Intervention

Overall, I consider that that an IIS rating of 3 (adequate) for both LC27 and LC28 is appropriate. While I consider that the safety mechanisms sampled are being maintained adequately and SL have appropriate processes to ensure that the plant is not operated, inspected, maintained or tested unless suitable and sufficient safety mechanisms are properly connected and in good working area, there are opportunities for improvement. These are primarily associated with the need to ensure consistent compliance with operational procedures and SL’s disciplined operations standards. These concerns are subject to continued specific intervention by ONR and are captured in an existing Regulatory Issue.

It was my opinion that THORP’s performance in its Criticality Assembly Area had significantly improved and had reached an adequate standard with SL demonstrating that it has the capability to appropriately deal with a genuine criticality event.  

I believe that THORP Senior management recognise ONR’s concerns regarding procedural use and adherence and conduct of operations and currently appear to be taking appropriate steps to address them.