Office for Nuclear Regulation

Torness - System Based Inspection - SBI 27 - Reactor Safety System - Trip Parameters 

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake a system based inspection of the reactor safety system trip parameters at EDF Energy Nuclear Generation Limited’s (NGL’s) Torness power station in line with the planned inspection programme contained in the Torness Integrated Intervention Strategy (IIS) for 2015/16.

Interventions Carried Out by ONR

As part of this intervention, the ONR Nominated Site Inspector and two C&I Specialist Inspectors performed a System Based Inspection (SBI) of the reactor safety system trip parameters to judge the system performance against its safety function.  Through examination of this system and associated sub-systems we performed compliance inspections against Licence Conditions LC10 (Training), LC23 (Operating rules), LC24 (Operating instructions), LC27 (Safety mechanisms, devices and circuits) and LC28 (Examination, inspection, maintenance and testing). LC34, which relates to leakage and escape of radioactive material and radioactive waste, was not considered applicable to the reactor safety system trip parameters.

Explanation of Judgement if Safety System Not Judged to be Adequate

From the inspection, we judge that overall the reactor safety system (trip parameters) meets the requirements of the safety case and is adequate.

Key Findings, Inspectors’ Opinions and Reasons for Judgements Made

Based on the areas sampled during this system inspection, it was found that Torness has adequate arrangements to ensure that the reactor safety system (trip parameters) is maintained and operated in accordance with the safety case and the station’s arrangements.

In summary, the outcome of the SBI of the reactor safety system trip parameters was:

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

In relation to the other activities undertaken in this intervention, no key findings arose.

Conclusion of Intervention

After considering all the evidence examined during the sample inspection undertaken against LCs 10, 23, 24, 27 and 28, we considered that the requirements of the safety case have been adequately implemented at Torness, with a rating of 2 (good standard) assigned against licence conditions 27 and 28.

Independently of this system based inspection, we identified delays in the provision of refresher training on the topic of emergency arrangements. We are satisfied that Torness is putting in place the necessary measures to address this issue.

There are no findings from this inspection that could significantly undermine nuclear safety.  At present, no additional regulatory action is needed over and above the planned interventions of Torness power station as set out in the Integrated Intervention Strategy, which will continue as planned.