Office for Nuclear Regulation

Readiness inspection to inform the permissioning decision to implement the MDF PCM safety case

Executive summary

Purpose of Intervention

On the 22 August 2019, the Office for Nuclear Regulation (ONR) undertook an intervention on the Sellafield site to:

This intervention record (IR) provides a record of the readiness inspection and will support ONR’s permissioning decision relating to the regulatory hold point, which requires the implementation of a new safety case for PCM operations at the MDF. This decision will be recorded in ONR’s Decision Record ONR-SDFW-DR-19-005.

The purpose of the intervention was to inspect SL’s implementation of their Licence Condition (LC) arrangements under LC22 “Modification or Experiment on Existing Plant”. The intervention sought to gain assurance that SL is in a suitable position to implement the MDF PCM safety case and to safely commence PCM operations and export from the MDF.

This intervention was undertaken in accordance with ONR’s Sellafield strategy to permission those activities which have been identified as presenting a higher risk.

Interventions Carried Out by ONR

The primary focus of this intervention was to inspect the MDF plant, processes and people, and to assess SL’s readiness to safely commence PCM operations. The ONR inspection comprised of desktop based discussions, on-plant inspections and dialogue with the Duly Authorised Persons (DAP).  I focused my inspection on the following key factors, which I consider important regarding SL’s readiness to implement the PCM safety case and to safely commence PCM operations within MDF:

During the inspection I examined evidence linked to these factors, including supporting arrangements that implement associated safety case limits and conditions.  I have inspected against LC22 (1), which requires the Licensee to ‘make and implement adequate arrangements to control any modification or experiment carried out on any part of the existing plant or processes which may affect safety’, using ONR’s technical inspection guide (TIG) NS-INSP-GD-022; this represents relevant good practice.  The supporting TIG outlines ONR’s expectations with regard to implementation of the modification. From a project readiness perspective the following are relevant: potential for impairment of the safety functionality or reliability of systems structures and components; training, plant configuration and records.

Explanation of Judgement if Safety System Not Judged to be Adequate

N/A – This was not a safety system inspection.

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

Based on the evidence sampled during this intervention, I judged SL’s implementation of its LC22 arrangements as Green (no formal action).  A number of outstanding issues were identified which, in the main, were self-identified by SL and are a reflection of SL’s current position with regard to their preparations for PCM operations. SL has a robust readiness governance process, which has yet to be completed and will address most of the aspects identified by ONR during this inspection. Where appropriate I will seek assurances from the SL Nuclear Independent Oversight (NIO) that the governance process has been appropriately applied and completed. 

SL demonstrated that sufficient DAPs have been trained in their SQEP role to control and supervise the PCM operations. During engagement with the DAPs, they:

Conclusion of Intervention

Based on the areas sampled during this inspection and the evidence gathered, I judge that SL’s implementation of their LC22 arrangements relating to the MDF PCM safety case to be green (no formal action).

In relation to SL’s state of readiness for the proposed the safe commencement of PCM operations and export from the MDF, I conclude that subject to addressing the aforementioned outstanding issues, SL has adequately implemented appropriate plant, processes, training and supervision.