Office for Nuclear Regulation

System Based Inspection (SBI) of Cabinet Extract Ventilation Finishing Line 6 (FL6)

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 Sub Division.

In accordance with that Strategy, a system based inspection (SBI) of the Cabinet Extract Ventilation Finishing Line 6 (FL6) within the Special Nuclear Materials (South) SNM (S) facility was planned.  The purpose of this planned inspection was for ONR to confirm the adequacy of implementation of the licensee’s safety case claims in respect of this system.

As part of each SBI, ONR examines evidence of the adequate implementation of six pre-defined licence conditions.  These licence conditions (listed below) have been selected because of their importance to nuclear safety, and are defined within the ONR’s formal process for delivery of an SBI.

Interventions Carried Out by ONR

LC 10 requires SL to make and implement adequate arrangements for suitable training of those who have responsibility for any operations that may affect safety.

LC 23 requires SL to produce adequate safety cases to demonstrate the safety of its operations, and to identify the operating conditions and limits necessary in the interests of safety.

LC 24 requires SL to make and implement adequate arrangements for the provision of suitable written instructions for undertaking any operation that may affect safety.

LC 27 requires SL to ensure that, before a system is operated, inspected, maintained or tested, there are suitable and sufficient safety mechanisms, devices and circuits properly connected and in good working order.

LC 28 requires SL to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.

LC 34 requires SL to ensure that its radioactive material and radioactive waste is at all times adequately controlled and contained, and that no leak or escape of that material or waste can take place without being detected.

I led a one and a half day, on-site, SBI of the Cabinet Extract Ventilation Finishing Line 6 (FL6) SNM(S), which is part of the SNM OU, with technical support from an ONR mechanical specialist inspector, the out-going & incoming ONR SNM OU site inspectors  and a ONR human factors specialist inspector. The inspection comprised discussions with SL staff, a plant walk down and a review of plant records and other documentation.

Explanation of Judgement if Safety System Not Judged to be Adequate

The Cabinet Extract Ventilation Finishing Line 6 (FL6) Protection Systems were judged to be adequate.

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

From the areas I targeted and the evidence I examined during this inspection, I consider that SL has adequately implemented those safety case claims that relate to the Cabinet Extract Ventilation Finishing Line 6 (FL6) Protection Systems.

The key personnel present during the inspection were knowledgeable with regards to the safety case and the functionality of the protection systems.

I sampled various safety case documents and judged they clearly defined operating rules and was satisfied that appropriate limits and conditions were identified to protect against the faults. I was also satisfied that the associated operating instructions were adequate to ensure compliance with the limits and conditions identified in the safety case.

A plant walk down was conducted and the facility was considered in reasonable condition for its age and that it is capable of reliably delivering the operational and safety requirements placed upon it. Individuals from site spoken to showed clear knowledge with regards to their roles and responsibilities when undertaking operational and maintenance activities.

I reviewed evidence of training records and the implementation of the safety case against the system function and found good knowledge demonstrated from operators and supervisors.

I sampled a range of maintenance documentation for components across the system and consider them to be adequate. SL demonstrated they have a detailed planned maintenance regime in place.

I observed a number of minor areas for improvement that will be tracked and managed in line with ONR normal business. 

I also agreed for the Sellafield Internal Regulator to take forward a potential minor improvement in procedures.

Based on the sampled evidence, I consider that a rating of Green (no formal action) is merited for Licence Conditions 10, 23, 24, 27, 28 and 34.

Conclusion of Intervention

From the evidence sampled during this inspection, I judge that the licensee has implemented adequately the sampled claims within its safety case.  Additionally, on the basis of the evidence requested and reviewed, I consider that the licensee’s formal arrangements for compliance with Licence Conditions 10, 23, 24, 27, 28 and 34 are also being implemented adequately.

No ONR Regulatory Issues were raised as a result of the inspection. The minor areas for improvement observed will be tracked and managed in line with ONR normal business.