Office for Nuclear Regulation

This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.

System Based Inspection – SBI 05 – Reactor Sea water systems

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at EDF Energy Nuclear Generation Limited’s (NGL’s) Heysham 2 power station in line with the planned inspection programme contained in the Heysham 2 Integrated Intervention Strategy (IIS) for 2015/16.

Interventions Carried Out by ONR

As part of this intervention, we performed a System Based Inspection (SBI) of the Reactor Sea Water (RSW) system.  Through examination of this system and associated sub-systems we performed compliance inspections against Licence Conditions LC 10: Training; LC23: Operating rules; LC24: Operating instructions; LC27: Safety mechanisms, devices and circuits; LC28: Examination, inspection, maintenance and testing. The inspections were based on sampling the implementation of the arrangements in place against each licence condition. 

Explanation of Judgement if Safety System Not Judged to be Adequate

From the inspection, we judge that overall the RSW system meets the requirements of the safety case and is adequate.

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

A safety case based system inspection of the reactor sea water system was carried out as part of the programme of SBIs included on the Heysham 2 site intervention plan for 2015/16, to judge the adequacy of the station arrangements to ensure the system will perform its’ safety function. The inspection considered compliance with a number of licence conditions to test the adequacy of the arrangements implemented. The standard consideration of licence conditions during safety system inspections includes LCs 10, 23, 24, 27, 28 & 34, with conditions added or excluded depending on their applicability. In this case, LC 34 was not included in the intervention as the team judged it was not applicable to this system.

During the course of the system inspection it was found that station has adequate arrangements to ensure that the RSW system is maintained and operated in accordance with the safety case and the arrangements based on the areas sampled by the inspection. The inspection identified a number of areas for potential improvement, and although none gave rise to significant concern, NGL has agreed to follow them up in accordance with their own arrangements.  I will monitor progress through routine regulatory business.

In summary, the outcome from the safety inspection of the reactor sea water system is that the arrangements and their implementation are deemed to be adequate, and therefore we have given an inspection rating 3 (adequate) in respect of LCs 10, 23, 24, 27 & 28.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Conclusion of Intervention

After considering all the evidence examined during the sample inspections undertaken against LCs 10, 23, 24, 27 and 28, we considered that the reactor sea water systems met the requirements of the safety case.

No actions or issues were identified during the inspection.

There are no findings from this inspection that could significantly undermine nuclear safety.