Office for Nuclear Regulation

Fellside Combined Heat and Power Plant, Steam Generation System Based Inspection

Executive summary

Purpose of Intervention

In accordance with the Office for Nuclear Regulation (ONR) strategy, each year ONR performs a series of planned System Based Inspections (SBIs). In line with the Sellafield, Decommissioning, Fuel and Waste (SDFW) division’s strategy, an SBI of Sellafield Limited’s (SL’s) Steam Generation System was planned in mid-2018 and conducted between 19-20 June 2018. The purpose of this inspection was for ONR to determine the adequacy of implementation of the safety case claims in respect of this system.

The Fellside Combined Heat and Power (FCHP) facility has an important duty role as it supplies process steam to a number of Sellafield site-wide operating facilities, including its high hazard and risk reduction work. Steam has an important safety function as it is used to transfer radioactive liquids via steam ejectors, as well as being used for heating and evaporation functions.

The SBI inspection was undertaken by a Structural Integrity Specialist Inspector, a Mechanical Engineering Specialist Inspector and the ONR SL Infrastructure site inspector.  This was a joint inspection with the EA.  SL's Internal Regulator also supported this inspection.

Interventions Carried Out by ONR

In order to determine the adequacy of implementation of the Licensee’s safety case claims in respect of this system, ONR examined evidence to determine compliance against six key Licence Conditions (LCs). These LCs (listed below) have been selected in view of their importance to nuclear safety and in providing a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.

ONR assessed compliance of the FCHP facility against the following standard set of LCs using applicable inspection guidance:

The inspection was conducted over the course of two days looking at compliance with the above LCs. It involved reviewing the applicable safety case claims and sampling, through a combination of document and record reviews, discussions with plant operators and a plant inspection to determine compliance against the selected LCs. SL’s Internal Regulator also observed this inspection.

Explanation of Judgement if Safety System Not Judged to be Adequate

I concluded that the safety case for the FCHP steam generation plant is adequately implemented.  I did identify some areas for improvement, which are described below.

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

Based on the areas I have targeted and the sampled evidence, I can conclude that the arrangements for implementing the safety case outputs are effective. Implementation is achieved through use of adequate plant and equipment to maintain the required steam generation capability in terms of availability and pressure. The key personnel present during the inspection were clearly knowledgeable with regards to the safety case, the functionality of the FCHP steam generation facility and requirements of system users.

The declared arrangements are adequately documented and there are suitable records to demonstrate that they are followed at all times.

A new safety case has been written this year.  The safety case will be modified in the future to provide details of the new Boiler Park and safety function as well as a more detailed analysis of the Sellafield end users of the steam.

Overall the FCHP steam generation facility may be considered to be straightforward in design, and having undertaken a plant walk down I am of the opinion that it is in reasonable condition for its age and that it is capable of reliably delivering the operational and safety requirements placed upon it. The Safety Features (SF) and Safety Related Equipment (SRE) identified in the safety case are present, in working order and clearly labelled.

Maintenance appears to be adequately managed and undertaken generally to schedule and to an appropriate standard. There is reporting software that determines the facility maintenance status and we saw evidence that this is used to report the status correctly.  ONR advised SL and PX to discuss maintenance postponements in more detail at their monthly meetings.

I concur with the FCHP steam generation safety case conclusion that the facility has no nuclear inventory associated with the site steam system; hence LC34 is not applicable for this inspection.

Through the inspection ONR identified two areas for improvement, specifically:

ONR has raised a single ONR Regulatory issue to capture these aspects.

Conclusion of Intervention

ONR inspection findings were shared and accepted by SL as part of normal inspection feedback.

I consider SL adequately demonstrated ownership and implementation of its FCHP facility steam generation safety case.

ONR has however raised one level 4 Regulatory Issue as a result of this inspection.  This issue will be tracked and managed in line with ONR normal business.