Office for Nuclear Regulation

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LC 7 Inspection – System Based Inspection (SBI) of the Waste Treatment Complex (WTC) ventilation system, Waste Effluent Deposition Directorate (WEDD) on Sellafield Ltd.’s nuclear licensed site at Sellafield, Cumbria

Executive summary

Purpose of intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interactions with Sellafield Limited (SL), the site licensee against a strategy defined by the ONR Sellafield Programme.  The content of my planned inspection schedule, PP5, for the current regulatory year (covering April 2015 – March 2016) is guided by that strategy.

I undertook this planned system based inspection of the Waste Treatment Complex (WTC) ventilation system by meeting with facility representatives from the Solid Waste Operating Unit. This OU was selected for inspection since it consists of a number of ageing facilities with a wide range of nuclear safety challenges and the possibility of the extension of operating life to provide waste management services for other areas of the site. This system was selected in view of its importance in preventing off-site contamination in the event of an accident at the plant while it provides waste management in the interests of high hazard reduction both on the Sellafield Site as well as the UK. The purpose of this inspection was for ONR to consider the adequacy of implementation of the licensee’s safety case claims in respect of this system.

The scope of the inspection took cognisance of the Long Term Periodic Review inspection within WTC due in a few weeks’ time and the inspection findings have been provided to the LTPR inspection team to enable both inspections to complement each other without any duplication of effort.

Interventions Carried Out by ONR

The intervention considered the following licence conditions to facilitate an assessment of the adequacy of the implementation of the ventilation system’s safety case:

I carried out a two-day, on-site, system based inspection of the ventilation system within WTC, with technical support from Control and Instrumentation (C&I) and Mechanical specialists.  The inspection comprised discussions with SL staff, a plant walk down and reviews of plant records and associated documentation.

Explanation of Judgement if Safety System Not Judged to be Adequate

The ventilation system was judged to be an adequate implementation of the safety case.

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

I consider that the safety case for the ventilation system is adequately implemented. However, I have, highlighted below some opportunities for improvement:

Site Licence Condition 10 – Training - IIS 3- Adequate

I examined evidence of the completion of required training for personnel within the facility, and assessed the awareness and competence of those personnel interviewed as part of the inspection. That sample confirmed that all personnel were suitably qualified and experienced; I therefore consider an IIS rating of 3 (adequate) for LC10 is merited.

Site Licence Condition 23 – Operating Rules - IIS 4- Below Standard

It is my opinion that an adequate Operating Rule review in line with extant site arrangements is required as the Operating Rule sampled is not set at an appropriate level that would facilitate the initiation of a response to regain control or mitigate consequences. Consequently, with respect to Site Licence Condition 23, I believe than an IIS rating of below standard (4) is appropriate. I have raised a regulatory issue to track the Operating Rule review to completion.

Site Licence Condition 24 – Operating Instructions - IIS 4- Below Standard

I sampled 14 safety designations to confirm the adequacy of implementation of the safety case. This was completed by comparing the sampled safety case and the subordinate Operational Clearance Certificate into which the afore-mentioned Safety Case was implemented. Of the sample, the majority of the safety designations had been amended without explanation, a Safety Mechanism, SM50 had been implemented as part a management decision but the Operational Clearance Certificate provided no auditable trail to the source of the decision. In addition, a number of operational documentation contained errors and, in particular, did not reflect the Operational Clearance Certificate.

With regard to the use of operating instructions, I believe that the fundamental requirements are being met but I noted some examples of procedures not being followed.

Consequently, with respect to Site Licence Condition 24, I believe that an IIS rating of below standard (4) is appropriate. I have raised a regulatory issue to track the required implementation to completion.

Site Licence Condition 27 – Safety Mechanisms, devices and circuits - IIS 3- Adequate

Overall, it was my opinion that the SMs, as sampled, were connected, in good working order, and were marked appropriately. I have highlighted a number of opportunities for improvement which had been identified by the Licensee and being addressed. I have asked that the rate of progress should increase. With respect to Site Licence Condition 27, it is my opinion that an IIS rating of adequate (3) is appropriate.

Site Licence Condition 28 – Examination, inspection, maintenance and testing - IIS 3- Adequate

Overall, work was being carried out in accordance with the site arrangements, it was my opinion that compliance with Licence Condition warranted an IIS rating of adequate (3). I have, however, highlighted a number of opportunities for improvement such as completed work recording and continuation of condition monitoring to improve equipment reliability. These improvements have been recognised by the Licensee and being addressed.

Site Licence Condition 34 – Leakage and escape of radioactive material and radioactive waste - IIS 3- Adequate

The Licencee stated that the glovebox ventilation ductwork has not been subject to radiological surveys, and was therefore unable to provide confidence that the system was maintaining containment. However, the robust construction of the ductwork and the absence of activity around the system provide some reassurance. It is my opinion that the Licensee should ensure a programme of routine surveys of the glovebox ventilation ductwork in particular at the point where joints such as flanges are present is implemented as soon as reasonably practicable to provide further reassurance. I have raised a regulatory issue to track the required implementation to completion.

Overall, it was my opinion that the arrangements were appropriate; however I have highlighted a number of areas for improvement. These improvements are known by Licencee and being addressed slowly. Consequently, with respect to Site Licence Condition 34, it is my opinion that an IIS rating of adequate (3) is appropriate.

Conclusion of Intervention

I have highlighted a number of observations which would provide ALARP improvements to the control of work, appreciation of the safety case and its requirements and general housekeeping. I noted that the Licencee is in the early stages of adopting good practices such as condition monitoring to improve asset reliability.

The key findings of this investigation were of the below standard quality of the Operating Rules, the below standard translation of the safety case into Operating Instructions and an inability to demonstrate that the ventilation was providing adequate containment. The findings of the inspection were shared with, and accepted by, the duty holders as part of normal inspection feedback. Three ONR regulatory issues have been raised as a result of this inspection.

The findings of this inspection have been shared with LTPR inspection team who will tailor their inspection to prevent any duplication of effort but also concentrate on specific findings in this report.