Office for Nuclear Regulation

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System Based Inspection (SBI)of the HALES Operating Unit cooling system and intelligence gathering meetings on Sellafield Ltd.'s nuclear licensed site at Sellafield, Cumbria

Executive summary

Purpose of intervention

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.

In accordance with that Strategy, a System Based Inspection (SBI) of the Highly Active Liquor Evaporation and Storage (HALES) Operating Unit (OU) HA Liquor Tanks cooling water system was planned for May 2016. ONR performs SBIs on the site's systems that are considered to be the most important to safety. SBI inspections are undertaken to confirm the adequacy of implementation of the licensee's safety case claims in respect of these systems.

When performing SBIs, ONR examines evidence of the adequate implementation of six pre-defined Licence Conditions (LCs). These LCs (listed below) have been selected because of their importance to nuclear safety and are defined within ONR's formal process for SBIs.

Interventions Carried Out by ONR

I led a two-day, on-site SBI of the HA Liquor Tanks cooling water system. I was supported by technical support contractors who are qualified mechanical and control and instrumentation engineers. The inspection comprised discussions with SL staff, plant walkdowns and reviews of plant records, the safety case and other documentation.

Explanation of Judgement if Safety System Not Judged to be Adequate

The HA Liquor Tanks cooling water system is judged to be adequate.

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

From the evidence which I sampled during this inspection, I consider that SL has adequately implemented those claims within the facility safety case that relate to this cooling water system.

I nevertheless raised a small number of regulatory observations related to the implementation and training associated with updating Operating Rules (ORs) and Clearance Certificate Operating Instructions (CCOIs) and I identified a minor shortfall related to the labelling of Safety Mechanisms (SMs), all of which were accepted by SL. Overall I did not identify any significant shortfalls in the delivery of safety functions or compliance arrangements and it is my opinion that an Inspection Rating of Green (No Formal Action) is merited for LCs 10, 23, 24, 27, 28 and 34.

As part of the scope of this SBI, I have also considered if the safety case that was the subject of this inspection might require a further ONR assessment of adequacy in a timeframe shorter than otherwise planned. Based on the information gathered during this SBI, I have no reason to recommend an early assessment of the safety case for this system.

Conclusion of Intervention

From the evidence sampled during this inspection, I judge that SL has adequately implemented the relevant claims within its safety case and that the formal arrangements for all the LCs against which I inspected are being adequately implemented. Notwithstanding this, I made a number of minor observations. SL fully accepted these and they will be followed up proportionately as part of normal regulatory business.