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Defuelling Outage RO17 - Mechanical Engineering inspection

  • Site: Sizewell B
  • IR number: 21-013
  • Date: April/May 2021
  • LC numbers: 28

Executive summary

Purpose of Intervention

The purpose of this intervention was to carry out licence compliance inspections at EDF Energy Nuclear Generation Limited’s Sizewell B power station in line with the planned inspection programme contained in the Sizewell B Integrated intervention Strategy for 2021/22.  This intervention is in support of the ONR decision on plant restart.

Interventions Carried Out by ONR

ONR inspectors carried out inspections against the requirements of Licence Condition 28: examination, inspection, maintenance and testing, to inform the ONR decision relating to the issue of a licence instrument for consent for return to service of Sizewell B following its periodic shutdown (Licence Condition 30).  The activities examined were selected due to their nuclear safety significance. Throughout this intervention record “I” refers to all the ONR personnel participating in the inspection.

The intervention sampled the examination, inspection, maintenance and testing performed during the periodic shutdown on safety systems and components; as specified in the Sizewell B Outage Intentions Programme.

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

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable

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

Based on my sampling, I am satisfied from a mechanical engineering perspective that during the Sizewell B 2021 (RO17) periodic shutdown:

  • Examination, inspection, maintenance and testing associated with reactor cooling pumps, high head safety injection system and safety injection system accumulators are being adequately controlled, in line with the requirements of the safety case.
  • The approach adopted by Sizewell B to the management of the safety and operability of the Polar Crane is appropriate. 
  • Sufficient records are being kept and monitored to identify problems both reactively and proactively.

Conclusion of Intervention

Based on my sampling undertaken as part of this intervention, I am satisfied that the Licence Condition 28 arrangements in place are adequate and have been adequately implemented with no significant shortfalls. I have therefore given this inspection a rating of GREEN.

From a Mechanical Engineering perspective, I support ONR permissioning the return of Sizewell B to power generation following its 2021 RO17 periodic shutdown under Licence Condition 30.