Project Overview

Electrical and Hazards


CRA provided safety case support, over several years, to the new nuclear build electrical team. This support included production of many deliverables that provides evidence to support the electrical safety case.


CRA has also supported the new nuclear build hazards team by developing a strategy for the hazard intermediate documents and hazard related sections of the safety report, including external hazards, internal hazards and combined hazards.

Project Scope



Deliverables included authoring support to the production of the electrical systems basis of safety case document that present clear and concise safety claims made on a system basis and detail the arguments and evidence to support them. CRA also delivered, or supported the delivery, of system substantiation documents for electrical sub-systems that provide the link between the high-level safety case requirements documents and the detailed system design descriptions.

Female worker in hi-vis jacket and helmet

CRA has also undertaken and reported the following deliverables to ensure that the electrical architecture and supporting information meets current standards:

Electrical Golden Thread Review to demonstrate the evolution (trace) of electrical safety functions is present in the documentation and the system functional requirements associated with these safety functions are reflected in the plant specifications from an electrical viewpoint. Five safety functions were assessed, and these safety functions were of varied types such as hazard, fault, human factors, operations, and diversity.

Relevant Good Practice (RGP) review, comparing the electrical architecture against international best practice. The review tabulated the most significant requirements from the IAEA Guidance and IEC 63046 and provided a statement on the compliance of the electrical design.

CRA undertook an Electrical Segregation Architecture Study that considered the segregation provided between the EDGs and UDGs, considering common cable routing.



CRA provided nuclear safety and maintain design integrity support to the safety case programmes branch which undertakes the role of intelligent customer. This role had a particular focus on the internal / external hazards aspects of the safety case. The safety case programmes branch is responsible for the overall development of the new nuclear build safety case, managing the configuration of the HPC safety case and performing some detailed technical studies including internal / external hazards, classification and radiation protection.


The scope of the work was to provide review and acceptance of hazards related studies defined within the List of Deliverables from HPC Responsible Designer.

Key Skills / Knowledge Applied

Safety Case (Claims, Arguments and Evidence)

Electrical Architecture

Tracing of safety functions through design and safety documentation

Relevant Good Practice / Industry Standards

Electrical Segregation

Internal and External Hazards

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