The UK’s Office for Nuclear Regulation (ONR) has completed Step 3 of the Generic Design Assessment (GDA) of China General Nuclear Power Corporation’s (CGN’s) UK HPR1000 design.

During Step 3, ONR increased its regulatory scrutiny and undertook a more detailed assessment of the design, focusing on the methods and approaches used by the GDA Requesting Party (RP) to underpin their safety and security claims.

General Nuclear System Ltd is the UK-registered company that was established to implement the GDA on the UK HPR1000 reactor on behalf of three joint requesting parties -  CGN, France’s EDF and London-based General Nuclear International (GNI).

Ana Gomez-Cobo, ONR’s Head of UK HPR1000 Regulation said: “The objective for GDA is to provide confidence that the proposed design is capable of being constructed, operated and decommissioned in accordance with the standards of safety, security and environmental protection required in Great Britain.”

She added: “During Step 3 of GDA we have undertaken assessment work across 19 technical disciplines and covered topics of a cross-cutting nature. Our assessment to date has not identified any fundamental safety or security shortfalls that would prevent us issuing a Design Acceptance Confirmation (DAC) for the UK HPR1000 design.”

However, ONR identified a number of areas for which requires further substantiation. “Although progress so far is encouraging, a lot of work by the Requesting Party is still required. We will continue to rigorously assess safety and security submissions throughout Step 4 of GDA,” said Gomez-Cobo.

A report summarising the assessment has been published on ONR’s website.

To date, three reactor designs have been assessed under the GDA process and received DACs from ONR and Statements of Design Acceptability (SoDA) from the Environment Agency (EA).

The UK EPR received its DAC and SoDA in December 2012, the Westinghouse AP1000 in March 2017 and UK ABWR in December 2017.

In January 2017, the UK government formally asked ONR and EA to begin the GDA of the UK HPR1000, which is proposed for deployment at Bradwell-on-Sea, Essex.

The GDA process calls for a step-wise assessment of safety and security submissions with the assessments increasing in detail as the project progresses.

The preparatory step, Step 1, for the UK HPR1000 GDA took place between January and November 2017.

Technical assessment of the design began with Step 2, which took place between November 2017 and November 2018.  It focused on understanding and assessing the fundamental safety and security claims, and acceptability, of the UK HPR1000 within the UK regulatory regime. 

Step 3 continued the assessment work of the previous step with increased emphasis on the arguments that underpin the safety and security claims.

ONR said overall, interactions with the RP throughout Step 3 have been constructive and that “its organisational arrangements have matured” during this step.

“Working arrangements have generally become embedded and coordination between the three organisations has improved,” according to the ONR assessment.

“The structure and organisation of the HPR1000 GDA RP is complex and some organisational issues still remain, such as lack of agility in decision-making mechanisms.”

However, ONR said it had seen strong commitment from General Nuclear System Limited, CGN and EDF to learn lessons from Steps 1, 2 and 3 and to improve their working arrangements in the final step.

“We expect to see the increased involvement of the Bradwell Power Generation Company, the prospective future licensee for the Bradwell B Nuclear Power Plant, during Step 4.”

ONR said the GDA is a voluntary process and not a legal requirement of the UK’s licensing regime for new power plants, but the government expects reactor designers to follow the process.

Completion of the GDA does not guarantee granting of a regulatory permit to begin construction or operation for a new nuclear power plant. The operator will have to obtain a nuclear site licence for that purpose.

The HPR1000, also known as Hualong One, is a 1100MWe Generation III pressurised water reactor.

The design is based on CGN's ACPR-1000, a more advanced version of CGN's Generation II CPR-1000 and China National Nuclear Corporation's ACP-1000 designs.

CGN is a majority shareholder in Bradwell Power Generation Company, a joint venture with EDF, which is planning to build a single HPR1000 plant at Bradwell B.

Photo: the HPR1000 reactor is planned for Bradwell B (Credit: CGN/EDF Energy)