Decision

Generic design assessment of Westinghouse Electric Company LLC's AP1000® nuclear power station design: supplement to the decision document (summary)

Updated 4 April 2017

Applies to England, Northern Ireland and Wales

Our role

As the environmental regulators for the nuclear industry in England (Environment Agency) and Wales (Natural Resources Wales), our role is to regulate discharges and waste disposals from nuclear power stations and to make sure that their impact on air, water and land is acceptable and minimised.

Generic design assessment (GDA)

In response to growing interest in nuclear power and potential applications to build new nuclear power stations in England and Wales, in 2007 we developed a new approach, GDA, for assessing the environmental acceptability of new reactor designs.

Westinghouse Electric Company LLC (Westinghouse) submitted its AP1000® nuclear power plant design to us for assessment in August 2007. In 2011, we issued an interim Statement of Design Acceptability (iSoDA) for the AP1000® and published our decision document, which provides full details of the GDA process.

We have now issued a full SoDA. This supplement to the 2011 decision document explains developments since 2011 and why we have issued a SoDA.

GDA means that we assess the acceptability of the generic environmental aspects of the nuclear reactor design before individual site applications are made. This approach allows us to get involved at the earliest stage where we can have most influence and where lessons can be learned for site-specific applications.

Through the GDA approach, we work closely with the Office for Nuclear Regulation (ONR), the UK regulator for nuclear safety and security. We make sure any new nuclear power stations built in the UK meet the highest standards of safety, security, environmental protection and waste management, and provide greater protection for both people and the environment.

Our 2011 decision

By issuing an iSoDA for the AP1000® design, we confirmed that we were content that the environmental aspects of the design would meet the high standards we expect. However, particularly significant, but still resolvable, issues remained that would need to be resolved before we would consider issuing a SoDA.

The 2 GDA issues we raised, jointly with the ONR, were:

• GI-UKAP1000-CC-02: ‘PCSR to support GDA’ - to provide a consolidated final GDA submission, including agreed design changes for the AP1000® reactor
• GI-UKAP1000-CC-03: ‘Consider and action plans to address the lessons learnt from the Fukushima Event’ - to demonstrate how Westinghouse has taken account of the lessons learnt from the unprecedented events at Fukushima.

Our decision document set out our detailed assessment of environmental aspects of the UK AP1000® nuclear power plant design. We used the comments and issues raised in our 2010 consultation to help inform our decisions.

Update to our decision

For both GDA issues, we asked Westinghouse to show how it would address them. Since December 2011 we have been assessing the further information Westinghouse provided. We are satisfied that Westinghouse has now fully resolved the 2 GDA issues, and we are issuing a full SoDA.

This supplement to our 2011 decision document summarises our assessment of Westinghouse’s response to the GDA issues, and details the changes to its submission. This supplementary document also summarises our assessment of the work Westinghouse has carried out to address other safety related GDA issues the ONR raised, where it has informed our final decision.

Changes to the submission

Westinghouse published its submission in 2011 and invited people to comment.

Westinghouse has revised its submission to reflect developments and to resolve the GDA issues. The submission includes an environment report with supporting documents. The changes made do not modify our previous assessment and conclusions. However, the changes have led us to make minor amendments and clarifications to a small number of paragraphs in our decision document and final assessment reports. These are set out in Appendix 2 of the supplement. We consider that the changes are not so significant as to require re-issue of revised documents. The documents we published in 2011 should now be read with the changes listed in Appendix 2 of the supplement.

When reviewing the additional information provided by Westinghouse in response to the GDA issues, we considered whether further consultation was necessary to help inform our assessments. We have concluded that the additional information received and its implications are not significant such that further consultation is required prior to issuing a full SoDA for the AP1000® design.

GDA issues raised by ONR

ONR also raised 49 safety related GDA issues as well as the 2 we issued together with them. We reviewed the information Westinghouse provided in response to these GDA issues and ONR’s assessment reports to see if there was any potentially significant impact on environmental matters or on our earlier decision. We conclude that the additional information provided does not change the conclusions or assessment findings in our earlier decision document.

ONR has also concluded that it is satisfied with the design and safety cases Westinghouse presented for the AP1000® reactor, and has issued a Design Acceptance Confirmation (DAC).

Further information on the ONR assessment.

Further assessment findings

GDA cannot provide a complete assessment of the final reactor design. There will be other issues relating to the specific operator or site that will be considered during the environmental permitting and site licensing stages. We raised 12 assessment findings in the 2011 decision document.

We would expect a future operator or licensee to address these findings during the detailed design, procurement, construction, commissioning or early operational phases of a new build project. As a result of our assessment of Westinghouse’s response to the GDA issues, including those raised by ONR, we have raised 6 further assessment findings. The assessment findings are set out in Appendix 3 of the supplement.

Our decision

We have completed a detailed assessment of Westinghouse’s GDA submission for the AP1000® nuclear power plant design, including the response to the GDA issues that we identified in our December 2011 decision document. We conclude that the environmental aspects of the design would meet the high standards we expect, and have decided to issue a SoDA for the design.

Next steps

The detailed design of the AP1000® reactor and the safety and environment cases that support it will evolve if operators take forward proposals for specific sites. We expect that the reactor design submitted for GDA and the statement of design acceptability would be used to support the permissions to build reactors of the AP1000® design that are more or less identical, apart from specific requirements for certain sites and operator choices.

Our SoDA and ONR’s DAC alone do not allow the construction of a nuclear power station to go ahead. A Development Consent Order from the Department of Business, Enterprise and Industrial Strategy’s Secretary of State, and a nuclear site licence from the ONR is needed.

The SoDA is valid for 10 years from the date of issue. After this time the AP1000® design needs to be reviewed and reassessed.