This was a planned inspection at EDF Energy Nuclear Generation Ltd's (NGL's) Dungeness B power station. It was undertaken as part of the planned intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR).
The work was carried out in-line with the planned inspection programme contained in the Dungeness B Integrated Intervention Strategy (IIS).
During this intervention, the following key activities were undertaken:
Following the fuel transport flask event in May 2017, where upon receipt at Sellafield a number of lid bolts were found to be not tensioned in accordance with the flask Package Operations and Maintenance Manual (POMM). Accompanied by a Flask Inspector I undertook an unplanned inspection to monitor progress against the improvements identified from the station's investigation and the requirements from ONR's enforcement letter dated 30 June 2017.
No system based inspection undertaken, hence not applicable.
The unplanned compliance inspection focussed on the flask receipt and dispatch operations and what improvements had been made since the event in May 2017. A document review of the Quality Plan, Fuel Flask Process Pack and a sample of the supporting operating instructions revealed the following;
It was confirmed during the inspection that the documentation is considered by the operators to be complicated and cumbersome, therefore is not used at point of use.
I judged that the station had undertaken a thorough investigation into this event and have put in place measures to prevent a direct recurrence. However, I consider the other action raised by the station to prevent re-occurrence to be fundamental in improving the arrangements to achieve compliance. From discussion with the station it is clear that work against this action has not yet commenced. Noting there have been further events relating to flask operations and the observations made during the plant walk-down regarding procedural use and adherence, I am of the opinion that the station's management arrangements as required by Carriage of Dangerous Goods and use of Transportable Pressure Equipment Regulations 2009 are not suitable and sufficient. ONR will now consider the appropriate response to these findings.
I undertook routine engagement with the station and the independent nuclear assurance team to discuss operational performance including recent events. I judge that the station is taking the appropriate action to management performance and investigate events. No significant nuclear safety concerns were raised during these discussions.
I held a meeting with the station's safety representatives; the meeting was open, informative and constructive. No safety significant concerns which needed further intervention were identified and I shared the feedback received on the outage performance with the plant manager and technical and safety support manager.
I discussed with the station leads, progress against regulatory issues. The information received will be used to update ONR's regulatory issues, no significant safety concerns were raised during these discussions and progress is being made in all areas.
The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.
The station has taken reasonably practicable improvements to reduce the potential for re-occurrence of the incident regarding de-tensioned lid bolts on EDF Dungeness B fuel transport flask dispatch to Sellafield through amendments to process documentation, equipment and training. However, the station has only addressed the immediate cause and not the root causes.
It is my opinion that the station has failed to address the root causes identified by its investigation. In doing so the station has failed to address ONR requirements issued within ONR's Enforcement Letter Ref DNB71293R. Therefore, I have assigned an IIS rating of RED - Demanding Improvement and have applied the enforcement management model. A regulatory issue has been raised to monitor progress against the enforcement action.
Post inspection, the station director has embargoed flask movements and since the inspection a fully resourced improvement plan has been provided for consideration.