Four separate Interventions are reported in this Office for Nuclear Regulation (ONR) Intervention Report:
All four Interventions were conducted by face-to-face meetings with key licensee personnel. Relevant documentation was also requested and examined and a visual inspection was conducted of key systems in the fuel storage pond.
A visual inspection of the fuel storage pond revealed no issues requiring regulatory attention. Maintenance records of key pond systems were sampled and all maintenance records examined were found to be in order.
A number of Condition Reports (CR) raised by the licensee, relating to the fuel storage pond, were discussed and in all cases it was judged that these had received a suitable degree of investigation and that appropriate actions had been taken to remediate the plant (where required) and/or to limit the potential for the event to occur again.
Finally, the licensee’s proposed post-Fukushima improvements to the pond and its operations were discussed and the improvements described were judged to be pragmatic and appropriate.
The anomalous findings of a third party Quality Assurance audit, of the supplier of SAAs to Sizewell B, were discussed and it was agreed that appropriate actions had been taken by the licensee to assure themselves as to the quality of the remaining batches of SAAs to be supplied. The same manufacturer also supplies RCCAs to site and this is a safety critical item. Accordingly, ONR asked the licensee to describe the steps they intend to take, to reassure themselves as to the quality of a recently ordered batch of RCCAs. We were satisfied that the licensee has both put an appropriately rigorous set of checks in place and also has contingency planning in place, should it not be possible to obtain reassurance that the RCCAs to be supplied are of adequate quality. ONR will continue to engage with the licensee to monitor progress in this area.
The licensee described the measures both they and the supplier of the tool, for RCCA measurements, have taken to ensure that a repeat of failure of the tool (as per that during Refuelling Outage 12) is unlikely. We were content that these measures are suitably diverse and comprehensive and this hence permits closure of the associated ‘Issue’ on the ONR Issues Database.
The licensee responded to an ONR Action to revisit their non-intact fuel management policy for Sizewell B and we discussed this response. We felt that the licensee’s response was disappointing as the current policy does not seem to have a robust underpinning justification. However, it was noted that the licensee is currently working on production of a policy for non-intact fuel management across its eight operating reactor stations (to ensure consistency of approach across the fleet). ONR agreed to have further discussions to ensure that the production of underpinning documentation forms a part of this exercise.
All four interventions undertaken were felt to have had a broadly acceptable outcome, although some further work was felt to be necessary by the licensee to underpin their non-intact fuel policy for Sizewell B.
No Recommendations were recorded under this Intervention.