The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee, Sellafield Limited (SL), against a strategy defined by the ONR Sellafield Programme. The inspection plan PP1 for the plutonium finishing and storage facilities details a strategic programme of regulatory inspections which includes a Licence compliance inspection of the Sellafield MOX (Mixed Oxide) Fuel Plant (SMP) in Plutonium Management Facility (South) (PMF(S)).
SMP is a facility that was intended to usefully burn up plutonium stocks by incorporating it into reactor fuel assemblies. The plant was closed following the Fukushima event. It is now in Post Operational Clean Out operations (POCO) pending decommissioning.
The purpose of this planned inspection was for the ONR to examine the adequacy of the SMP permit to work system. This system is used to control plant being taken out of service, maintained and re-instated and governs any electrical or mechanical isolations that may be necessary to safely undertake work. SMP have recently been experiencing some issues with control and supervision of operations in this area and this inspection was targeted specifically at the permit to work system as this is important to the maintenance of nuclear and conventional safety.
ONR undertook a planned two and a half day system based inspection (SBI) between 20 and 22 October 2015, delivered by the site inspector and a structural integrity specialist inspector. We sampled the implementation of the licensee’s arrangements for compliance against ONR guidance for two licence conditions.
Licence Condition 25 requires the licensee to ensure that adequate records are made of the operation, inspection and maintenance of any plant which may affect safety. The aforesaid records shall include records of the amount and location of all radioactive material, including nuclear fuel and radioactive waste, used, processed and stored or accumulated upon the site at any time.
Licence Condition 26 requires the licensee to ensure that no operations are carried out which may affect safety except under the control and supervision of suitably qualified and experienced persons appointed for that purpose by the licensee.
We utilised the following ONR guidance:
The inspection included a general discussion of the requirements set out for the system in the facility safety case and relevant safety documentation, a plant walk down and individual discussions with relevant plant safety case and operational personnel.
Not applicable; this was not a safety system inspection.
We consider that the licensee’s arrangements for compliance with LC25 have been effectively implemented at SMF (S). Our inspection found that compliance generally exceeded guidance requirements but there were a few minor improvements that could be made, all of which were accepted by the licensee. We consider that SMF (S)’s implementation of the licensee’s arrangements for LC25 is good in many areas; its Records Schedule was well set out and maintained, and the documents sampled provided a link back to the safety case. Some records no longer in use in the facility were still included in the Records Schedule, but the licensee provided an adequate explanation to justify the inclusions. We considered this was a minor shortfall. Consequently, we consider that the inspection merits an IIS rating of 2 (good standard) against LC25. It is my opinion that the minor shortfall does not present a significant safety concern.
We consider that the licensee’s arrangements for compliance with LC26 have also been effectively implemented at SMF(S). There were a number of areas of good practice, and a number of improvements that could be reasonably made, all of which were accepted by the licensee. It is our opinion that SMF (S)’s implementation of the licensee’s arrangements for LC26 is good in many areas. I consider that its planning process for level 2 (previously approved instructions) and level 1 (new work instructions, typically activities with greater complexity and those classified as high impact/risk work) is well controlled and robust. This is offset by our identification of some areas for improvement relating to issuing of work control authorisations (WCA), confirmation of isolations immediately prior to issuing WCAs, and confirmation of plant configuration (including isolations) on completion of WCAs. Consequently, we consider that the inspection merits an IIS rating of 3 (adequate) against LC26. It is our opinion that the identified areas for improvement do not present a significant safety concern.
We consider that SMF (S)’s control and supervision of maintenance and operational activities are adequate. In the near future, there is likely to be an increase in the variety of work activities undertaken in SMP, including POCO, operations, care and maintenance and Dounreay Exotics Storage Facility. We consider that these often disparate work steams could stress the extant arrangements for controlling and supervising work activities covered by work control authorisations and discussed a number of relatively simple and straightforward measures that could help mitigate any potentially detrimental effects on its control and supervision of the increasing variety of work activities.
Arising from our inspection findings against LC26, two Regulatory Issues were raised. The ONR site inspector will manage their close out as part of normal regulatory interactions with the licensee.