Office for Nuclear Regulation

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Sizewell B - Inspection Week

Executive summary

Purpose of Intervention

The purpose of this intervention was to undertake a Licence Condition (LC) compliance inspection at EDF Energy Nuclear Generation Ltd’s (NGL’s) Sizewell B power station, in line with the planned inspection programme of the Operating Facilities Operating Reactors sub-programme intervention plan for 2017/18.

Interventions Carried Out by ONR

During this intervention, ONR observed the annual Level 1 demonstration (Exercise Eagle 17) of the site’s emergency arrangements under LC 11(5). I participated in the emergency control centre in order to convey information to the Redgrave Court Incident Suite (RCIS) to support the Level 2 element of the exercise.

Explanation of Judgement if Safety System Not Judged to be Adequate

No system inspection was undertaken during this intervention.

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

During the course of the exercise a number of observations were made including positive elements as well as opportunities for improvement. Principal observations are listed below, including one area for improvement that will require an explicit response from NGL, which will be conveyed by letter:

The station did not however adequately demonstrate its capability to deploy and connect deployable back-up equipment (DBUE); specifically the connection of the suction side of the high pressure pump to the condensate storage tank and simulated connection to the reserve water storage tank (RWST) valve house. The station will be required to re-demonstrate this element of the exercise objectives within a shift exercise or other appropriate context.

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

ONR considered that overall, the station presented overall an adequate demonstration of its emergency arrangements, thus warranting an inspection rating of ‘Green’.

However, in view of an inadequate demonstration of the deployment and connection of deployable back-up equipment, the station has been requested to re-demonstrate this particular element of its emergency arrangements during an appropriate exercise within 6 months. This will be tracked via a Level 3 regulatory issue.