Office for Nuclear Regulation

Sellafield Utilities - Site Steam Distribution - System Based Inspection

Executive summary

In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, each year ONR performs a series of planned system based inspections (SBIs) targeted on key safety significant systems.  The purpose of this particular intervention was to undertake a System Based Inspection (SBI) on the Sellafield Limited (SL) Steam Distribution System confirm the adequacy of the implementation of the safety case.

An inspection was undertaken of the claims made in the safety case to ascertain compliance against Licence Conditions (LC) 10, 23, 24, 27 and 28. Licence Condition 34 was not applicable to this inspection as there is no radioactive material within the steam distribution system. The inspection sampled a range of operating procedures, maintenance instructions, and staff training records and included an inspection of the steam distribution system.

Interventions Carried Out by ONR

Between 21st and 22nd January, I carried out a planned 1.5-day inspection of the Steam distribution system utilising specialists from the following technical disciplines:

The inspection involved reviewing the applicable claims in the safety cases and then sampling suitable evidence to determine compliance against the selected LCs on the plant. This was achieved through a combination of document reviews, plant inspections and discussions with operators and maintenance staff.

I assessed Steam Utilities compliance against the following LCs by using the following ONR inspection guidance documents:

Explanation of Judgement if Safety System Not Judged to be Adequate

This safety system was judged to be adequate.

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

During the inspection, there were a number of shortfalls identified which were judged to be relatively minor when compared against the above guidance. I have raised a Level 4 regulatory issue relating to SL’s use of the control room mimic board to manage changes in system configuration. I have also identified a shortfall in record keeping for certain maintenance activities. I have discussed this with the SL corporate site inspector, who is going to seek improvements in this area at a corporate level. This is being tracked through an existing Level 2 regulatory issue.

Overall, I found LCs 10, 23, 24, 27 and 28 to be adequately implemented in relation to the systems inspected. The identified shortfalls are minor in nature and do not impact the overall delivery of the steam system safety functions, therefore, it is my opinion that for this system based inspection a rating of GREEN (no formal action) is appropriate for LCs 10, 23, 24, 27, and 28.

Conclusion of Intervention

From the evidence sampled during the inspection, I judge that the SL Utilities team managing the Steam Distribution Systemhave adequately implemented the relevant claims in the safety case and that the formal arrangements for LCs 10, 23, 24, 27, 28 are being adequately implemented.

I discussed the shortfalls with SL who have recognised and accepted the need to address the minor shortfalls. Overall, I judge that the safety system is adequate and fulfils the requirements of the safety case.