This intervention is part of ONR’s programme of inspections of Sellafield Ltd’s Periodic Safety Reviews (PSR) and specifically considered the Finishing Line 5 (FL5) conversion facility’s Long Term Periodic Review (LTPR). This facility, operated by the licensee Sellafield Ltd (SL), was considered to be an appropriate target for an intervention because foreseeable events on this plant could result in a significant offsite release. Furthermore, it forms part of the Magnox fuel reprocessing route which supports the strategically important Magnox Operating Programme (MOP). Following cessation of routine operations, the facility will undergo Post Operation Clean Out (POCO) before entering a decommissioning phase.
The objective of this intervention was to gain suitable confidence that SL has adequately reviewed the extant safety case and is taking the necessary steps to ensure that the plant will continue to be operated in a manner that continues to reduce risks as low as reasonably practicable (ALARP), supports the MOP and ensures a suitable entry into its decommissioning phase.
This inspection of FL5 examined SL’s compliance with Licence Condition (LC) 15 (the requirement to undertake Periodic Safety Reviews of the safety case. It followed lines of enquiry informed by a fault studies scoping report carried out by ONR specialist inspectors and developed through discussions with the inspection team. The intervention focused on SL’s review of FL5’s safety case with respect to fault sequences with potentially large public dose consequences.
Our inspection found that SL had appropriately identified a significant number of potential improvements that should be implemented and which it intends to progress through its LTPR improvement programme as part of ongoing workstreams. Our inspection did not reveal any matters of substantive concern that had not already been identified by the licensee in its own review. We did, however, identify three additional areas for improvement that SL agreed to address, the progress of which will be monitored by ONR.
Based on the inspection findings, I consider that SL has undertaken an adequate LTPR of the FL5 conversion facility. Consequently, I have awarded an IIS rating of 3 (Adequate) against LC15.