Office for Nuclear Regulation

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PF&S OU (PP1) - System Based Inspection (SBI) of the Sellafield Package Resin Store (SPRS) Ventilation System in Plutonium Manufacturing Facility South (PMF(S)) at Sellafield

Executive summary

Purpose of intervention

Site: Sellafield –

Title: PF&S OU (PP1) - System Based Inspection (SBI) of the Sellafield Package Resin Store (SPRS) Ventilation System in Plutonium Manufacturing Facility South (PMF(S)) on Sellafield Ltd.’s (SL) nuclear licensed sites at Sellafield, Cumbria.

    1. Purpose of Intervention
  1. 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, Decommissioning, Fuel and Waste Programme.  The inspection plan PP1 for the Plutonium Finishing and Storage facilities Operating unit (PF&S OU) details a strategic programme of regulatory inspections which includes a System Based Inspection (SBI) of the Ventilation system in PMF(S).
  2. The purpose of this inspection is for ONR to examine whether the licensee’s safety case claims in respect of the Sellafield Package Resin Store (SPRS) ventilation system have been adequately implemented. This system is responsible for providing store cooling as well as providing a suitable working environment for personnel and equipment. Parts of the ventilation system also contribute to the confinement of radioactive substances safety function.
  3. ONR’s SBI process examines evidence to determine compliance against six key licence conditions (LCs). These LCs (listed below) have been selected in view of their relevance to ensuring nuclear safety and provide a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.

Interventions Carried Out by ONR

  1. LC 10 requires SL to make and implement adequate arrangements for suitable training of those who have responsibility for any operations that may affect safety.
  2. LC 23 requires SL to produce an adequate safety case to demonstrate the safety of its operations, and to identify and implement operating conditions and limits necessary in the interests of safety.
  3. LC 24 requires SL to make and implement adequate arrangements for the provision of suitable written instructions for undertaking any operation that may affect safety.
  4. LC 27 requires SL to ensure that, before a system is operated, inspected, maintained or tested, all safety mechanisms, devices and circuits are properly connected and in good working order.
  5. LC 28 requires SL to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.
  6. LC 34 requires SL to ensure that its radioactive material and radioactive waste is at all times adequately controlled and contained, and that no leak or escape of that material or waste can take place without being detected.
  7. I carried out an SBI of the SPRS Ventilation system over the course of two days. I was assisted by another ONR site inspector and an ONR Mechanical Specialist inspector.  I was also accompanied on this inspection by SL staff from its internal regulatory organisation. The inspection comprised discussions with SL staff, physical viewing and inspections of targeted structures, systems and components (SSCs) through a plant walk down, and examination of a sample of plant operational and training records. The inspections were carried out in accordance with the following ONR inspection guidance:
  1. LC 10  Training, NS-INSP-GD-010 Revision 4, July 2014
  2. LC 23  Operating Rules, NS-INSP-GD-023 Revision 4, March 2016
  3. LC 24 Operating Instructions, NS-INSP-GD-024 Revision 3, February 2016
  4. LC 27 Safety Mechanisms, Devices and Circuits, NS-INSP-GD-027 Revision 3, January 2016
  5. LC 28 Examination, Inspection, Maintenance and Testing (EIMT), NS-INSP-GD-028 Revision 5, July 2016
  6. LC 34 Leakage and Escape of Radioactive Material and Radioactive Waste, NS-INSP-GD-034 Revision 3, April 2016

Explanation of Judgement if Safety System Not Judged to be Adequate

  1. The safety case supporting this system was judged to be implemented adequately.

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

  1. From the areas I targeted and the evidence I examined during this inspection, I consider that SL has implemented adequately those safety case claims that relate to the SPRS ventilation system.
  2. I consider the facility’s implementation of the site’s arrangements for the six LCs is good in many areas.  For instance, the staff interviewed had a good knowledge of the existing arrangements and state of equipment, and provided good evidence to this effect in response to questions.
  3. I consider the licensee provided examples of Relevant Good Practice (RGP), such as the SPRS filter management process and the use of a passive store cooling system.
  4. I took confidence from the use of the Ventilation Technical Support Group (VTSG) as an independent check of the health of the SPRS ventilation system.
  5. In the course of my inspection I did not identify any significant concerns with the adequacy of the licensee’s safety case for this system that would necessitate an earlier than planned assessment by ONR.

Conclusion of Intervention

  1. My inspection outcome was shared and accepted by the licensee as part of normal inspection feedback.
  2. I concluded that the SPRS ventilation system meets the requirements specified for it in SL’s safety case and consequently it is my opinion that an inspection rating of Green is appropriate for compliance against LCs 10, 23, 24, 27, 28 and 34.