Corporate report

Generic design assessment of nuclear power stations: summary report on initial assessment of General Nuclear System’s UK HPR1000 reactor design

Updated 20 February 2019

1. Introduction

New nuclear power stations are an important part of the government’s plans for generating secure low carbon electricity. Regulators are scrutinising new nuclear power station designs thoroughly, making sure people and the environment are properly protected.

General Nuclear System Ltd (GNS), known as the Requesting Party, submitted the UK HPR1000 design to the UK nuclear regulators (Office for Nuclear Regulation and Environment Agency) for generic design assessment (GDA). GNS is acting on behalf of the 3 joint requesting parties: China General Nuclear Power Corporation (CGN), Électricité de France S.A (EDF S.A) and General Nuclear International (GNI). CGN have developed the HPR1000 plant and it is now under construction in China.

GDA is the process that allows us to begin scrutinising new nuclear power station designs well in advance of specific sites being identified and construction starting. This means that we can identify any potential design issues at an early stage and ask the reactor design company to address them. This helps to avoid any potential costly and time-consuming changes during construction.

We have now completed our initial assessment of the UK HPR1000 design. This is a summary of our initial statement of findings report.

2. New nuclear power stations – the government’s view

The UK government has outlined its commitment to new nuclear developments in the UK. It states that nuclear power, together with gas and renewable energy, such as wind and solar power, will help meet the country’s energy needs in the future. It will also meet its commitment to reduce carbon emissions. As part of the development of new nuclear power stations, it has asked nuclear regulators to assess the safety, security and environmental impacts of new reactor designs before they are built.

3. Regulating nuclear power stations

The Environment Agency regulates the impacts of nuclear sites in England on people and the environment by issuing environmental permits to cover site preparation, construction, operation and decommissioning. We also work closely with the Office for Nuclear Regulation (ONR), which regulates the safety and security aspects of nuclear sites. When we use the term ‘nuclear regulators’, we refer to Environment Agency and ONR.

Government and industry expect power stations of similar design might be built on a number of sites and potentially be run by different operating companies. Therefore, we have split our regulatory process for assessing and permitting the operational stage of new nuclear power stations into 2 parts.

The first phase is GDA, when we carry out assessments of designs and, at the end, we provide a statement about the acceptability of each design. There may be matters that cannot be resolved at GDA, these are captured as ‘GDA issues’ and ‘assessment findings’, which are associated with any statement issued.

A ‘GDA issue’ is an unresolved issue that is significant, but resolvable, and which requires resolution before construction of the reactor starts. The company must publish a ‘resolution plan’ setting out how it will address the issue. All GDA issues must be resolved to the satisfaction of the regulators before GDA can be completed.

An ‘assessment finding’ is an unresolved issue that is not considered critical to the decision to start construction - it will need to be addressed during the design, procurement, construction or commissioning phase of the new build project.

In the second phase, following GDA, we receive applications for environmental permits for a specific site. We take into account all of the work we have done during GDA, so that our efforts are focused on site-specific matters, including how the operator is addressing GDA assessment findings. We will also carry out further public consultation before deciding whether to issue operational permits for a specific site.

4. Generic design assessment

GDA is a joint process by the ONR and the Environment Agency. GDA means that we begin assessing the acceptability of the environmental aspects of a design before an application is made to build the power station. We get involved with designers and potential operators at the earliest stage when issues can be best addressed effectively and efficiently before construction begins.

There are a number of stages for GDA:

1. Initial assessment - we assess the information submitted at a high level only and may ask the Requesting Party for more information or design changes to be made. This is the stage we are at now.
2. Detailed assessment - we assess the information in detail and we form our preliminary views to go to consultation.
3. Consultation - we ask for views following detailed assessment.
4. Post consultation review - we consider all responses to the consultation.

5. Decision and statement - we decide whether to issue:

   • a statement of design acceptability (SoDA)
   • an interim SoDA if there are any outstanding issues to be addressed
   • no statement of acceptability

GDA is based on a generic site. When we assess applications for environmental permits, we use the actual characteristics of the specific site where it is proposed to build. The site-specific characteristics may be different from those of the GDA generic site. More details of our GDA process can be found in our process and information document (Environment Agency, 2016).

5. The UK HPR1000 design

There are various types of nuclear reactors around the world, with over 400 in operation. One of the most common types is the pressurised water reactor (PWR), of which the HPR1000 is one of the latest designs. Capable of producing around 1,180 megawatts of electricity, enough to power more than 2 million homes on average, the HPR1000 is currently under construction in China.

PWRs work by transferring heat that has been generated inside the reactor, via a heat exchanger to a secondary circuit. Steam is generated in the secondary circuit and this makes the turbine spin and it drives a generator producing electricity.

A simplified illustration of the UK HPR1000 reactor

Image courtesy of GNS

The proposed site for construction of the UK HPR1000 reactor is Bradwell, in Essex.

More information on the UK HPR1000 is available on GNS’s website.

6. Consulting the public

The GDA process allows the public to have their say. The Requesting Party is encouraged to publish detailed design information on its website and to update it as new information becomes available.

Anyone can view that information and comment on it. The Requesting Party is required to respond to questions and comments about its design. We see the questions and the responses, so that we can consider them in our assessments. Comments can also be made to the regulators’ Joint Programme Office.

The UK HPR1000 ‘comments process’ was launched on 16 November 2017, so that the public could view and comment on the submission. As part of this process:

• information about GDA and the comments process, with links to GNS’s website, has been provided on the joint regulators’ website
• GNS has published its submission (apart from any sensitive nuclear or commercially confidential information) on its website, allowing comments to be made electronically or by post to GNS
• GNS has publicised its submission and the comments process by advertising the details on the UK HPR1000 GDA website
• we also publicised the second phase of GDA and the comments process through the media and directly to stakeholders - see press release on GOV.UK

The regulators (ONR and the Environment Agency) have considered comments received up to 31 August 2018 and GNS’s responses to those comments during our initial assessments.

Comments received after 31 August 2018 will be considered during the next stage of our assessment.

7. Our initial assessment

In our initial assessment, we examined GNS’s submission concerning its management systems and the radiological impact of the reactor in detail, and in brief for other aspects. We wanted to find out if:

• we needed more detailed information
• there were any issues in the design that were clearly not acceptable
• there needed to be any significant changes to the design

Our main findings are summarised in sections 7.1 to 7.8. The full report, our statement of findings of the initial assessment for the UK HPR1000 (Environment Agency, 2018) is available on GOV.UK.

7.1 Quality management systems

A quality management system makes sure that an organisation’s work is of a high quality and can be monitored and measured. GNS’s parent companies CGN and EDF Energy both have ISO 9001:2008 quality management systems. GNS has developed an appropriate quality management system that includes specific management system arrangements for the GDA project. We are satisfied that GNS has developed and implemented a suitable management system for this stage of the GDA project.

7.2 Generic site description

A generic site is a fictional site GNS has defined that represents UK conditions. The generic site includes details of assumed weather and marine parameters that would affect dispersion of discharges of radioactive waste, as well as places where people live and food is produced. This information is used to assess the potential impact of radiation. However, many parameters are taken from the Environment Agency Initial Radiological Assessment Tool without consideration of why they are appropriate for use in this GDA. We will consider this further as part of our detailed assessment.

7.3 Impact of radioactive discharges

From our assessment of the amount of radioactive waste that could potentially be produced (see section 7.4), we have concluded that we need more evidence that these estimates are as accurate as they can be. We have also raised questions about how the impact assessment was made. We will continue to assess the estimated impact throughout our detailed assessment.

The estimated radiological impacts of the UK HPR1000 calculated by GNS is below the constraint of 300 µSv/y from any new single source of radioactive discharge for humans, and below the dose criteria for wildlife of 10 µGy/h. Based on the information we have at present, it is unlikely that the impact from the radioactive discharges would exceed UK public dose limits.

7.4 Radioactive waste management

We ask GNS to identify all sources and types of waste produced, provide estimates of the amount of waste produced (volume and activity), and show how each type of waste will be disposed of. GNS has identified the possible sources and types but not the amount of waste generated by the UK HPR1000. It has not yet provided an integrated waste strategy. However, it has identified the differences between the current arrangements for managing radioactive waste at Fangchenggang unit 3 (the reference plant in China) and those needed for the UK. We need more information to be able to make a detailed assessment.

7.5 Best available techniques

We use best available techniques to avoid producing waste or, if this is not possible, to make sure the amount of waste produced is as low as possible. GNS is making progress in demonstrating that its UK HPR1000 design will use these techniques to protect the environment, but it still needs to provide more in-depth information for our detailed assessment.

7.6 Estimates of radioactive discharges and limits

We expect GNS to provide evidence to support its estimates of radioactive discharges from the UK HPR1000, and to show that they compare favourably with similar power stations around the world. GNS has provided estimates for the UK HPR1000 discharges based on those estimated for the reference plant, Fangchenggang unit 3. We understand these estimates are based on theoretical calculations using the Chinese regulatory methodology and assumptions. However, estimates for the UK HPR1000 will be based on operational data of the HPR1000 and predecessor designs.

Based on the estimates we’ve received so far, the amount of radioactive waste generated by this design is unlikely to exceed that of similar power stations across the world, but GNS has still to demonstrate this fully. The proposed discharge estimates and limits are likely to be appropriate, but we require further evidence to underpin the numbers presented for detailed assessment.

7.7 Monitoring radioactive discharges and disposals

The GNS submission briefly describes final liquid and gaseous discharge monitoring arrangements and states that information on the arrangements for in-process monitoring will be provided in later stages of GDA. No details of the arrangements for monitoring solid waste and non-aqueous waste have been included.

There is currently not enough information for us to decide whether GNS’s proposals for measuring and assessing discharges and disposals of radioactive waste are acceptable. We need more information for our detailed assessment.

7.8 Other environmental regulations

The HPR1000 will need to comply with many other areas of environmental legislation as well as the Radioactive Substances Regulation, which is the focus of GDA. A power plant will need cooling water, diesel generators and non-radioactive substances to operate, and it will also generate non-radioactive waste.

GNS proposes that the UK HPR1000 will use seawater for cooling. We need more information on how it plans to do this, to make sure that marine life is adequately protected. There is not enough information in the submission on proposed non-radioactive discharges. We will need this information to proceed to detailed assessment. But, we realise that we cannot assess many of the potential effects until an application for a specific site is made.

The submission states that there will be no discharges to water below ground. The submission also states that there is no plan for an incinerator on the site. There is no information on the amount of dangerous substances that will be stored on site. We need this information for the detailed assessment.

For all of the areas where we need more information, GNS has agreed to provide this during our detailed assessment stage.

8. Conclusions

In this initial assessment of GDA we examined the management systems used for producing the submission and the impact of the proposed radioactive discharges.

Our assessment also considered whether GNS’s submission for the UK HPR1000 contained any issues that are clearly unacceptable in the UK and, therefore, whether any significant changes to the design might be needed.

We also assessed whether there was enough information to carry out the detailed assessment stage.

The overall conclusions of our initial assessment for the UK HPR1000 nuclear power station design, based on the information we have received so far, are:

• we did not find any matters within the submission that are obviously unacceptable
• we have not identified any significant design changes that are likely to be needed before we could issue a permit
• GNS has an appropriate management system in place to control the content and accuracy of the information it provides for GDA
• the annual impact of radiation from the UK HPR1000 on people is likely to be below the UK public radiological dose limit and the constraint from any new source
• based on the information we have at present, it’s unlikely that radioactive discharges would exceed those of similar power stations
• the submission made by GNS for stage 1 assessment does not contain enough information for us to carry out a detailed assessment

These conclusions are based on our initial assessment. We may add more or amend our conclusions when GNS has provided all the information we need, and we’ve carried out our detailed assessment.

We will only proceed to detailed assessment of the UK HPR1000 and subsequent consultation when we’re satisfied that the regulators and GNS are ready to do so. This detailed assessment is expected to begin in November 2018, subject to a readiness review undertaken by the Requesting Party and the regulators.

9. Next steps

We’ve set out our GDA process to be open and transparent and there are a number of ways you can get involved. You can:

• comment during Step 3 of the process via GNS’s website
• take part in our consultation - we will consult on our preliminary findings from our detailed assessment and carefully consider all the comments and use these to inform our assessments and decisions about nuclear power station designs
• talk to us at site stakeholder groups, local community liaison councils and public events

10. References

Environment Agency, 2016: Process and information document for generic assessment of candidate nuclear power plant designs, Version 3, Environment Agency, October 2016.

Environment Agency, 2018: Generic design assessment of candidate nuclear power plant designs - Initial assessment of General Nuclear System’s UK HPR1000 design: Statement of findings