Project Overview

A new fault had been defined for inclusion within the Safety Case, and associated Fault Schedules, for a fleet of nuclear power stations. To support the modification of the site Safety Case, a safety submission was required for each station to demonstrate that the radiological risk potentially arising from the initiating fault is tolerable and As Low As Reasonably Practicable (ALARP). This involved the identification of adequate protection to minimise the fault consequence and to demonstrate that this protection can perform its duty under fault conditions and for the duration required.


To achieve this, vital expertise came from human factors specialists, chemists, transient analysts, and mechanical and electrical engineers. The safety submission was required to implement adequate controls and maintenance regimes for any plant with a claimed safety measure. Supporting procedures and training were also required where the protection is dependent on operator action. Following the approval from appropriate governance stakeholders (internal and external to the client), the submission ultimately updated the suite of living safety documentation for each site.

Project Scope

CRA were contracted to produce the safety submissions to modify the Safety Case at several nuclear power stations. This involved working closely with the wider safety case team, including safety case leads and station representatives (e.g., Operators and plant system owners), as well as other technical experts responsible for supporting aspects of the case (e.g., Human Factors specialists).


During production of the safety submission, CRA compiled the supporting evidence (this involved authoring ALARP optioneering reports, scoping the necessary assessments and reviewing their outcomes), and drafted updates to station documentation for agreement and implementation on site. CRA supported regulator and nuclear safety committee communications across the fleet, as well as supporting the project interactions between the different teams.


CRA were responsible for the authoring and verification of several safety case submissions to introduce a new fault into the Fault Schedule of a nuclear power station.

Key Skills / Knowledge Applied

Safety Case Authoring.

Safety Case Verifying.

Technical Report Writing.

Station Documentation Updates.

ALARP Optioneering.

Faults and Hazard Schedules.

Complex safety case management and liaising with Station.

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