Office for Nuclear Regulation

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Sellafield - Planned system based inspection (SBI) of the Highly Active Laboratories

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 system based inspections (SBIs) targeted at key safety significant systems. The purpose of this inspection was for ONR to determine the adequacy of implementation of Sellafield Ltd.’s (SL’s) safety case claims in respect of the Thermal Oxide Reprocessing Plant’s (THORP’s) Highly Active (HA) Laboratories.

Interventions Carried Out by ONR

Between 6 - 7 June 2017, ONR carried out a planned 2 day inspection of the THORP HA laboratories utilising specialists from the following technical disciplines:

In order to determine the adequacy of implementation of the licensee’s safety case    claims in respect of this system, ONR examined evidence regarding the implementation of SL’s arrangements for six pre-defined licence conditions (LCs), as listed below. These LCs have been selected in view of their importance to nuclear safety and are defined within ONR’s formal process for system based inspection.

The inspection involved reviewing the applicable safety case claims and sampling, through a combination of document reviews, plant inspections and discussions with operators and maintenance staff, suitable evidence to determine compliance against these LCs on the plant.

ONR assessed compliance in THORP against the following LCs using the applicable ONR inspection guidance:

Explanation of Judgement if Safety System Not Judged to be Adequate

N/A - this system is judged to be adequate.

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

From the evidence sampled during the inspection, I consider that SL has adequately implemented those claims in the safety case that relate to the HA Laboratories. Consequently, it is my opinion that for this system based inspection a rating of GREEN (no formal action) is appropriate for license conditions 10, 23, 24, 27, 28 and 34.

There were no significant shortfalls identified during this inspection. I did however raise a minor shortfall against LC10, regarding the omission of a safety significant operating instruction in operator training packs. I will follow this up with a minor regulatory issue.

I also raised minor observations against LC 27 and LC34 that I suggested SL may wish to consider implementing. However given the minor significance of these observations I do not consider it proportionate for any formal follow up action to be raised and I will not be following these up with SL.

Conclusion of Intervention

From the evidence sampled during the inspection I judge that SL has adequately implemented the relevant claims in the safety case and that the formal arrangements for each of the LCs inspected are being adequately implemented. I conclude that the safety system is adequate and fulfils the requirements of the safety case. I have raised one new regulatory issue to manage closure of the minor shortfall against LC 10.