- Site: Sellafield
- IR number: 21-104
- Date: October 2021
- LC numbers: 15
Executive summary
Purpose of Intervention
The Office for Nuclear Regulation undertakes all regulatory interactions with the Sellafield Site Licensee against a strategy defined by the ONR Sellafield, Decommissioning, Fuel and Waste Division. The strategy requires inspections to be performed against Licence Condition 15 relating to periodic safety reviews, which requires the licensee to make and implement adequate arrangements for the periodic and systematic review and reassessment of safety cases.
The purpose of this intervention is for ONR to assess the adequacy of the Highly Active Liquor Evaporator and Storage facility Periodic Safety Review and to ensure that Sellafield Limited is taking the necessary steps to continue to operate and maintain the plant in a manner that ensures that the plant risks are as low as reasonably practicable.
The three broad objectives of this intervention were to:
- Gain confidence that Sellafield Limited has undertaken an adequate Periodic Safety Review; accounting for lessons learnt and future foreseeable challenges.
- Gain confidence that the extant facility arrangements and the safety case are suitable and sufficient, and mitigate shortfalls awaiting improvements.
- Establish if Sellafield Limited has credible resolution plans to implement improvements identified by the Periodic Safety Review in a timely manner.
- The inspection also provided an opportunity for ONR to gather information on the condition of Highly Active Liquor Evaporator and Storage facility and the contribution that the plant makes to ONR’s strategic priority at Sellafield of high hazard risk reduction.
Interventions Carried Out by ONR
On 13-14 October, ONR conducted a one-and-a-half day inspection of Licence Condition 15 compliance relating to Highly-Active Liquor Evaporator and Storage facility (HALES). The ONR inspection team was assembled following the submission of Sellafield Limited’s Periodic Safety Review (PSR), and consisted of:
- Nuclear Liabilities Regulation Inspector;
- Mechanical Engineering Safety Inspector;
- Control and Instrumentation (C&I) Safety Inspector; and
- Periodic Safety Review Project inspector
The intervention involved:
- Sampling the process and technical aspects of the application of Sellafield Limited Periodic Safety Review arrangements and associated documents.
- Discussions with appropriate members of Sellafield Limited staff with reference to the identified lines of inquiry.
- An inspection of HALES facility and associated structures, accompanied by the Operations Support Manager, Safety Case Manager, Lead System Engineer, Operating Unit Engineering Manager and Sellafield’s internal regulator.
The following ONR guidance was utilised as part of the inspection:
- NS-INSP-GD-015, Revision 5, Periodic Review.
- NS-TAST-GD-050, Revision 8, Periodic Safety Reviews (PSR).
- ONR Safety Assessment Principles (SAP), Rev.1
Explanation of Judgement if Safety System Not Judged to be Adequate
This was not a system-based inspection; therefore, no judgement has been made on the adequacy of the implementation of any specific part of the safety case.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Based upon sampling of submitted documents, discussions with Sellafield Limited staff and the plant inspection, ONR considers that Sellafield Limited has not met the requirements of Licence Condition 15 with an adequate periodic safety review of HALES.
The HALES Periodic Safety Review (PSR) highlighted that there are some safety significant shortfalls identified during the previous PSR that are outstanding. ONR sampled these and found out that some remaining safety significant work has not progressed since 2012. As example, we identified a safety significant shortfall relating to substantiation for a number of items important for nuclear safety. This position is not in line with Sellafield Limited’s LC15 arrangements.
The currently adopted HALES PSR relies on system health reports to identify and show health and reliability issues in real time. ONR judged there to be significant shortfalls in Sellafield Ltd undertaking system health reviews in a timely manner. Additionally, the current list of issues on the Sellafield Asset Management database is not up to date and not correlated to system health report recommendations.
Based on the above key findings, ONR considers that:
- Sellafield Limited has not undertaken an adequate PSR, which accounts for lessons learned and foreseeable future challenges.
- Sellafield Limited arrangements to address the actions identified during the PSR are not adequately implemented.
ONR inspectors made the following observations about the PSR process:
- The HALES implemented corporate PSR arrangements, that calls for a fit for purpose approach proportionate to the risk context of the facility. Considering the facility’s ageing equipment, it is imperative to identify life limiting features and age-related degradation mechanisms in order to be able to identify and deliver improvements significant for safety.
- HALES ability for resolution of outstanding safety significant shortfalls has been shown to be ineffective. Two Short Term Periodic Reviews (STPR) in 2015 and 2018 did not identify and provide adequate justification for not closing safety significant shortfalls including the substantiation shortfall for safety equipment.
- ONR highlighted that communication from the HALES team was open and transparent, and commended the positive practice of introducing an annual safety case review as part of standard business.
- During the inspection, ONR provided regulatory advice on areas for improvement identified as part of this compliance inspection that do not directly affect the inspection rating to (a) EC&I - alarm panel labelling; reliability of the non-safety classified control room Supervisory and Data Acquisition system, and (b) review of assumptions for decommissioning planning.
Conclusion of Intervention
Based on the evidence sampled during the inspection, ONR considers that Sellafield Limited has not effectively implemented its arrangements for compliance with Licence Condition 15. ONR therefore judges, noting the ONR guidance on inspection rating, that an inspection rating of AMBER (seek improvements) is appropriate for compliance against Licence Condition 15 (periodic review).
A level 3 regulatory issue (RI-9049) was raised to track improvements to address the compliance gap. Additionally, ONR gave two pieces of regulatory advice to highlight minor areas for improvement.