Office for Nuclear Regulation

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Mechanical Inspector – 2.1 V Green – Harwell nominated site inspector

Executive summary

Purpose of intervention

This was a planned inspection at Research Sites Restoration Ltd’s (RSRL’s) Harwell site, undertaken as part of the planned intervention strategy for the Harwell site for 2014/15.

Interventions Carried Out by ONR

In relation to Licence Condition 23 (LC23) “operating rules” we (Harwell nominated site inspector and ONR mechanical inspector) considered two topics.  The first was RSRL’s LC23 compliance arrangements whilst the second was implementation of these at the B462 Complex.  These topics were selected since we were not familiar with RSRL’s LC23 arrangements and operations which may affect safety are undertaken in the B462 Complex.  We focussed on the “adequate safety case”, “identify conditions and limits necessary in the interests of safety” and “operations are at all times controlled and carried out” aspects of the LC since these are particularly important for demonstrating that nuclear safety risks are maintained As Low As Reasonably Practicable (ALARP).

In relation to Licence Condition 24 (LC24) “operating instructions” I (Harwell nominated site inspector) considered two topics.  The first was RSRL’s LC24 compliance arrangements whilst the second was implementation of these at the B462 Complex.  I focussed on Maintenance Instructions (MIs), since the earlier LC23 compliance inspection had considered an instruction dealing with plant operation.

In relation to Licence Condition 28 (LC28) “examination, inspection, maintenance and testing” I (Harwell nominated site inspector) considered two topics.  The first was RSRL’s LC28 compliance arrangements whilst the second was their site wide implementation.  These topics were selected since I was not familiar with RSRL’s LC28 arrangements and I wished to inspect maintenance activities on buildings across the site which may affect safety.  Such building maintenance contributes to demonstrating safety until the radiological hazard in the building is removed.  I selected building B220.

In relation to Licence Condition 35 (LC35) “decommissioning” I (Harwell nominated site inspector) considered two topics.  The first was RSRL’s LC35 compliance arrangements whilst the second was implementation of these at the Liquid Effluent Treatment Plant (LETP).  These topics were selected since I was not familiar with RSRL’s LC35 arrangements and decommissioning was currently underway at the LETP.

I held a meeting with the RSRL safety representatives, to support their function of representing employees and receiving information on matters affecting their health, safety and welfare at work.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

In relation to LC23, we considered that some additional documents should be referenced in RSRL’s LC23 arrangements, but noted that these are already in the RSRL Management System.  We raised an issue relating to this.  We observed a lack of visibility of parts of the safety case pending completion of the new Operational Safety Case for B462 and full implementation of Living Safety Case Summaries, but noted that these matters are already being addressed by ongoing work.  We observed a clear link between the safety case and the conditions and limits necessary in the interest of safety and from the Safety Management Requirement sampled we observed that the plant was being operated in line with the defined conditions and limits necessary in the interests of safety.  Taking all these factors into account we assigned an Integrated Intervention Strategy (IIS) rating of 3 (adequate) to LC23.

In relation to LC24, I noted that RSRL had already identified during a review that some additional existing Management System documents should be referenced in their LC24 arrangements.  I will leave RSRL’s review and the subsequent revision of their LC24 arrangements to complete.  I inspected the MI for an item of Key Safety Related Equipment (KSRE) at the B462 Complex, including its last use on the plant.  I had concerns relating to:  a) identifying the type of use on the MI (e.g. should it be followed step by step);   b) providing a hold point to confirm that safety related starting conditions have been met;  c) independent verification at the most safety critical hold points;  d) provision of advice on what actions to take if a hold point cannot be released.  I raised an ONR issue relating to these concerns.  Taking all these factors into account I assigned an IIS rating of 4 (below standard) to LC24.

In relation to LC28, I identified no issues during my review of LC28 compliance arrangements and my sampling of implementation of LC28 compliance arrangements at B220.  I noted that maintenance on plant which may affect safety, such as the building structural survey of B220 that I sampled, is in the same category as maintenance on plant which does not affect safety.  I noted that I would consider this matter further during a future LC28 inspection.  Taking all these factors into account I assigned an IIS rating of 3 (adequate) to LC28.

In relation to LC35, I noted that LC35 arrangements were not in place to review safety cases, modify them if a significant decommissioning milestone is to be changed and for ONR to permission the most significant changes.  I noted that some but not all such arrangements were already in the RSRL Management System.  I raised an ONR issue relating to this.  I was satisfied that LETP decommissioning was proceeding in line with RSRL’s LC35 arrangements and consider that good quality evidence was provided to support the LETP decommissioning sampled.  Taking all these factors into account I assigned an IIS rating of 3 (adequate) to LC35.

In relation to the other activities undertaken in this intervention, no key findings arose.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Conclusion of Intervention

From the evidence gathered during this intervention, no matters have been identified that are likely to have a significant impact on nuclear safety on the site at this time. Therefore, no additional regulator action arising from this visit is considered necessary at this time.