Office for Nuclear Regulation

System Based Inspection – Electrical System

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake a system based inspection of the Site Electrical System at the Low Level Waste Repository Ltd’s (LLWR) licensed site in line with the planned inspection programme contained in ONR’s LLWR Integrated Intervention Strategy (IIS) for 2015/16.

Interventions Carried Out by ONR

ONR Electrical Specialist Inspectors performed a system based inspection (SBI) of the LLWR Site Electrical System to judge the system’s performance against its safety function and to review the adequacy of actions taken, at a site-wide level, on loss of power. Licence Conditions (LC) considered during the inspection included  LC 10 (Training), LC 23 (Operating rules), LC 24 (Operating instructions), LC 27 (Safety mechanisms, devices and circuits), LC 28 (Examination, inspection, maintenance and testing) and LC 34 (Leakage and escape of radioactive material and radioactive waste).

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable.

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

The ONR Specialist Inspectors considered that:

 LLWR has adequate arrangements to ensure that the Site Electrical System is maintained and operated in accordance with the safety case and the site’s arrangements.

The nuclear safety case arguments placed on the Site Electrical System are limited and are not significantly compromised by foreseeable loss of power scenarios.

In summary, the outcome from the SBI of the LLWR Site Electrical System is that the system adequately fulfils the requirements of the safety case. 

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

The ONR Specialist Inspectors considered that the Site Electrical System met the requirements placed on the system from the site nuclear cases.

From the information gathered and evidence obtained during this inspection no new significant matters have been identified that are likely to have significant impact on nuclear safety at this time.