Guidance

New nuclear power stations: assessing reactor designs

The Environment Agency’s Generic Design Assessment (GDA) of new nuclear power station designs and how we engage with others during the process.

The Environment Agency, Office for Nuclear Regulation (ONR) and Natural Resources Wales (NRW) are working together to make sure that any new nuclear power stations built in the UK meet high standards of:

  • safety
  • security
  • environmental protection
  • waste management

Generic Design Assessment

Government has stated that nuclear power plays an important role as part of a mix of different energy sources. In 2007 the UK government asked the regulators to work together to introduce a new process for assessing designs for new nuclear power stations.

The Environment Agency and ONR developed a process called Generic Design Assessment (GDA). They use this process to scrutinise new nuclear power stations at an early stage. This is before a developer has formed detailed proposals for building at a specific site or applied for licences or permits. This means that the regulators can identify potential design or technical concerns early on and ask the designer to resolve them.

The process has 3 steps, with the assessment becoming increasingly more detailed. If the design company still has significant issues to resolve after the regulators have completed their planned assessments, further steps can be added to the process.

It takes around 4 years to complete the 3 steps of the GDA process:

  • Step 1: Initiation
  • Step 2: Fundamental Assessment
  • Step 3: Detailed Assessment

The design company must provide detailed information to make the environment case for their nuclear power station design. The regulators will carefully examine the information and will ask questions. They will request further information if necessary and identify if changes to the design might be needed.

At the end of each step, the regulators issue statements and reports about their findings. What they issue will depend on the scope of the GDA they agreed with the design company during Step 1.

If the agreed scope is sufficiently broad and detailed, with the potential to achieve a ‘Statement of Design Acceptability’ (SoDA), then we will consider issuing one. We will only issue a SoDA if we judge that the design is acceptable. Similarly ONR will consider issuing a ‘Design Acceptance Confirmation’ (DAC).

Issuing a SoDA and DAC means that the regulators consider that if a new nuclear power station were built using that design, it should be capable of meeting the UK’s high standards of safety, security and environmental protection.

Before a site operator can build a new nuclear power station, they must apply for and obtain all of the site specific approvals they need. These include:

  • environmental permits for construction and operation
  • a development consent order (planning permission) from the Secretary of State for Business, Energy and Industrial Strategy
  • a nuclear site licence and other safety and security consents from ONR

When making decisions about an operator’s environmental permit applications for a proposed site, the Environment Agency will take account of all the work it has done during GDA.

More information about GDA

The regulators have produced some infographics about GDA.

Modernised GDA process and updated guidance

In 2019 the regulators modernised the GDA process, using their learning from previous assessments. They have made the process more flexible to help with the assessment of small modular reactors. This includes providing other options for the GDA outcome, in addition to the current option of issuing (or not) a DAC and SoDA.

The Environment Agency has produced updated guidance for organisations who want to submit a design for assessment. We refer to these organisations as ‘requesting parties’ because they can be made up of a number of companies, including nuclear power station designers and operators. The guidance explains the GDA process and the information they must provide.

In developing the modernised GDA process the regulators have been careful to make sure that a requesting party still has to meet the same requirements and expectations to achieve a SoDA and DAC.

The regulators began a GDA of the UK HPR1000 nuclear power station design before they issued updated guidance. This GDA is following earlier versions of guidance produced by the Environment Agency and by ONR.

The regulators will be using the updated guidance for all future GDAs.

Public and stakeholder engagement

GDA is an open and transparent process. The nuclear regulators worked with Sciencewise to understand how the public wants to be informed and consulted about assessing new nuclear power station designs. Read the final report about this work.

There are a number of ways the public and other stakeholders can get involved in GDA.

GDA comments process

A nuclear power station design company going through GDA must set up a website to:

  • publish information about the design
  • invite the public to ask questions and make comments

The design company must respond to any comments or questions they receive.

The regulators will see the comments and questions and the responses provided. They can also use this information to help inform their assessment work.

The Environment Agency and ONR have set up a Joint Programme Office (JPO) to help administer the GDA process. During GDA, the JPO acts as a single point of contact between the regulators and the design company. The public and stakeholders can also send their comments to the JPO.

The comments process is open throughout a GDA. It closes about 4 months before the regulators issue statements at the end of steps 2 and 3, or make decisions about issuing a SoDA or DAC.

The comments process document on the ONR website has more information about how it works.

Consulting on GDA findings

The Environment Agency will consult on its preliminary GDA findings from the detailed assessment if the scope agreed with the requesting party is sufficient to consider issuing a SoDA. This follows the same approach as the original GDA process. If the agreed scope is not sufficient to consider issuing a SoDA, the Environment Agency will not consult.

The Environment Agency will carefully consider all the comments we receive during the consultation on our preliminary findings. We will use the comments to help inform our assessment and decision about whether to issue a SoDA for a particular design.

Meetings and events

You can talk to the Environment Agency about assessing new nuclear power station designs at:

  • site stakeholder groups
  • local community liaison councils
  • industry conferences
  • public events

To find out when these will take place, email the Environment Agency: nuclear@environment-agency.gov.uk.

Ongoing and completed GDAs

Information about GDAs that are in progress or have ended.

General Nuclear System Ltd - UK HPR 1000

The regulators began assessing General Nuclear System Ltd’s UK HPR1000 in January 2017. They moved to Step 2 of the GDA in November 2017 and completed the initial, high level technical assessment in November 2018.

Read the summary report of the findings from this initial assessment.

The regulators are now carrying out the next step of GDA involving more detailed assessments. They are aiming to complete the GDA for this design in late 2021, when they will decide whether they can issue a SoDA and DAC.

The comments process for this GDA opened in November 2017. It will stay open until around 4 months before the regulators make their decision.

You can make comments or ask questions about this design on the General Nuclear System website.

You can also email comments to the JPO: new.reactor-build@onr.gov.uk.

You can find out more about this GDA on the joint regulators website.

Bradwell B Power Generation Company Ltd proposes building this reactor design at its Bradwell site in Essex.

EDF and Areva - UK EPRTM

The regulators began assessing EDF and Areva’s UK EPR nuclear power station design in 2007. The Environment Agency consulted on its findings from its environmental assessment from 28 June to 18 October 2010 and published its decision and interim SoDA in December 2011.

In December 2012, the regulators completed their GDA of this design and concluded that it should be capable of meeting UK safety, security and environment protection requirements.

EDF Energy are building this reactor design at Hinkley Point in Somerset.

Find out more about the Environment Agency’s regulation of Hinkley Point nuclear power station.

EDF also propose to build this design at Sizewell in Suffolk.

Read the consultation, assessment and decision documents related to this GDA.

Read information about this design on the EDF website.

Hitachi GE UK Advanced Boiling Water Reactor (ABWR)

The regulators began assessing Hitachi GE’s UK ABWR nuclear power station design in January 2014. The Environment Agency and NRW consulted on their findings from their environmental assessment from 12 December 2016 to 3 March 2017.

In December 2017 the regulators completed their GDA of this design and concluded that it should be capable of meeting UK safety, security and environment protection requirements.

Horizon Nuclear Power propose building this reactor design at Wylfa Newydd on Anglesey and at Oldbury on Severn in South Gloucestershire.

Read the regulators’ documents about the GDA for this design.

You can also read information about this design on the Hitachi GE website.

Westinghouse Electric Company AP1000®

The regulators began assessing Westinghouse Electric Company’s AP1000 nuclear power station design in 2007.

The Environment Agency consulted on its findings from its environmental assessment from 28 June to 18 October 2010. It published its decision and an interim SoDA in December 2011.

In March 2017 the regulators completed their GDA of this design and concluded that it should be capable of meeting UK safety, security and environment protection requirements.

Read the regulators’ documents about the GDA for this design.

You can also read information about this design on the Westinghouse website.

Contacts

Email the Environment Agency: nuclear@environment-agency.gov.uk.

Email the Office for Nuclear Regulation: contact@onr.gov.uk.

Sign up for the nuclear regulators’ new reactors joint e-bulletin.

Sign up for the Environment Agency’s nuclear regulation e-bulletin, email: nuclear@environment-agency.gov.uk.

More information

Read the government’s National Policy Statement for nuclear power generation.

Volume 1

Volume 2

Read the government’s guidance for developers of new nuclear power stations.

Read about how the Environment Agency, ONR and NRW work together on GDA.

Read about ONR’s work on nuclear new build.

Read about NRW’s work on nuclear new build.

Published 1 November 2019