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) of the Segregated Effluent Treatment Plant (SETP) at Sellafield

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) strategy, an SBI of SL’s Segregated Effluent Treatment Plant (SETP) was planned and conducted between 10th-11th October 2017.  The purpose of this inspection was for ONR to determine the adequacy of implementation of the safety case claims in respect of this system.

SETP handles low risk, low active acidic and alkaline effluents arising from Magnox and THORP reprocessing operations.  These streams are treated in SETP to make them suitable for sea discharge via the Break Pressure Tank.

Although SETP is low consequence in terms of radiological hazards the continued safe operation of SETP is important in supporting SL’s reprocessing operations and hence supports SL’s overall hazard and risk reduction activities across the SL site.

This SBI was conducted as a joint inspection with the Environment Agency (EA) given the common areas of interest with the SETP facility.  However, this Intervention Record only captures ONR’s key regulatory observations.  The regulatory observations from the EA are recorded within their own inspection report.

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 in SETP against the following 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 reviews, discussions with plant operators and plant inspections to determine compliance against the selected LCs.  SL’s Internal Regulator also supported this inspection.

Explanation of Judgement if Safety System Not Judged to be Adequate

Based on the sampling undertaken, I judged the safety case supporting SEPT to be adequately implemented.

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

From the areas I targeted and the evidence examined during the inspection, I consider SL has adequately implemented those safety case claims that relate to SETP.

Whilst some minor deficiencies and anomalies against SL’s compliance against LC10 - Training, LC 27 - Safety Mechanisms & LC 28 - EIM&T were identified, I consider the significance of these deficiencies to be low.  As such, I awarded inspection ratings of Green (No formal action).

I consider SL provided an adequate level of assurance and evidence to demonstrate compliance against LC 23 - Operating Rules, LC - 24 Operating Instructions &  LC 34 - Leak and escape.  As such, I awarded inspection ratings of Green (No formal action).

Consequently, it is my opinion that an overall rating of Green for the SETP system as a whole, is appropriate.

Conclusion of Intervention

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

I consider SL adequately demonstrated ownership and implementation of the SEPT safety case to ensure and maintain nuclear safety.