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Common comment themes


As part of the GDA process we invited members of the public and interested parties to comment on the reactor design information and the formal regulatory submissions. The comments process has now closed, and we have summarised some of the common themes that have been received and our responses.

We received a number of comments which were out of scope of the GDA process. The GDA process did not cover national nuclear policy and principles, nor did it address the strategic siting of nuclear power stations or the proposals being made for any specific nuclear power station projects such as Bradwell B in Essex. Out of scope comment themes are reflected at the end of this section.

All comments were accepted, reviewed and answered.

Technical comments and questions

We received a range of questions and suggestions about the reactor technology that is being assessed by the UK nuclear regulators and when additional information will be made available about the deployment of this technology at prospective nuclear power station sites.

Some people asked about the quality and safety of reactor components. Throughout both the GDA phase and the future site licence phase for UK HPR1000, the quality of reactor components will be ensured and assured through multiple aspects of the design and quality management arrangements.

Some comments have suggested using emerging nuclear technologies, rather than using existing pressurised water reactor technology. These new reactor technologies will not be available in time to meet the country’s electricity demands in the short and medium term. CGN and EDF are therefore proceeding with the tried and tested technology of pressurised water reactors.

Comments have been received about the stability of a Pressurised Water Reactor (PWR). From a neutronics perspective, PWRs are in fact inherently stable in that they have a negative temperature feedback coefficient. That is to say, if the temperature of the fuel increases, then the reactivity of the reactor core decreases. Further details about the reactor core design can be found in chapter 5 of our Pre-Construction Safety Report.

Some comments have been received about the water supply. The primary and secondary circuits, as well as the safety systems, use demineralised water produced using freshwater from a third party townswater supplier. Sufficient water is stored on site for replenishment of the primary and secondary circuits and the safety systems in the event of any incident or emergency. Seawater will be used in cooling systems associated with the turbine/generator systems, and as the ultimate heat sink for the safety systems. Further details about the reactor coolant system and the safety systems can be found in chapter 6 and chapter 7 of our Pre-Construction Safety Report.

One commenter asked about the design not including a core catcher. The UK HPR1000 reactor incorporates a facility for flooding the space surrounding the reactor with water so that reactor components are maintained within the reactor vessel, thus the need to have a core catcher has been eliminated. Further information on our severe accident management measures can be found in chapter 13 of our Pre-Construction Safety Report.

One commenter asked about the firefighting water tanks, the design for the UK HPR1000 includes two separate water tanks per reactor for firefighting purposes and accords with the relevant IAEA guidance.

One commenter asked about containment ventilation and filtration. There are two systems provided in the UK HPR1000 design, which function to filter air being released from the inner containment, if this is required. The first system operates during normal plant operation to reduce the concentration of radioactive substances and aerosols in the containment, if required. Its operation would be subject to the operational controls and levels agreed with the Regulators.

The second system is available to operate, if required, following a severe accident. The purpose of this system is to reduce the pressure within containment by venting gas through a purifying filtration vessel. The operation of this system would be subject to specific operational conditions pre-agreed with the Regulator.

Chinese and French involvement

Some comments have been received about the companies and countries involved in the UK HPR1000 reactor.

General Nuclear System Limited has been established to act on behalf of the three joint requesting parties (CGN, EDF and General Nuclear International) to implement the Generic Design Assessment of the UK HPR1000 reactor.

Both CGN and EDF are highly respected, global developers and operators of nuclear power stations around the world with excellent safety records, and have successfully worked together for more than 30 years. Both CGN and EDF operate large fleets of nuclear reactors to the highest of safety standards. CGN in China and EDF in the UK and France are known and respected in the global nuclear community for the safe operation of their fleets and invite regular international independent review via the WANO (World Association of Nuclear Operators) Peer Review Programme – this includes reviews prior to the start-up of new reactors.

Nuclear waste and spent fuel

A number of comments have been received about the storage and management of radioactive waste and spent fuel.

The radioactive waste from the UK HPR1000 reactor will be similar in terms of volume and level of radioactivity to that from other Pressurised Water Reactors. The nuclear power industry takes full responsibility for all of its waste, unlike other forms of power generation. The volume of waste generated is also relatively small.

The spent fuel from a nuclear power station is radioactive and potentially dangerous so it has to be managed carefully. However, active cooling of the spent fuel is only required for the first 5 years or so following removal from the reactor core. This, together with the small volume of material involved, means that long term storage is relatively straightforward from a technical perspective.

Our proposals for the UK HPR1000 include a period of safe on-site storage for higher activity waste and spent fuel, followed by transfer to a proposed UK Geological Disposal Facility (GDF).

As part of the GDA, we received assurance from the Radioactive Waste Management (RWM) company that the anticipated waste will be acceptable for disposal at the GDF. The future licensee will continue to work with the RWM and provide specific and detailed proposals in due course, at site-specific stage, considering all issues identified by RWM during GDA.

Further information on the radioactive waste management arrangements can be found in chapter 23 of our Pre-Construction Safety Report and chapter 4 of our Pre-Construction Environmental Report.

Climate change

Some comments asked about the consideration of climate change in the GDA, with specific mention of flooding and potential impacts on onsite radioactive waste storage facilities which will remain onsite after the reactor is decommissioned.

Climate change effects are considered within the UK HPR1000 design on a conservative basis for all applicable external hazards, using the latest published UK Climate Projection data (UKCP18). These include assessments of rises in sea level, sea temperature and air temperature as well as associated extreme weather events as part of the derivation of the generic site envelope parameters. Sea level rise is a gradual process which will allow reassessment of the design safety margins over the lifetime of the power plant as climate change projections are updated. UK regulation requires us to re-evaluate our plants against new, or changing, hazards and implement changes to satisfy safety requirements.

For the UK HPR1000, climate change has been considered in the design for 60 years of operation and for a period of decommissioning of approximately 20-25 years. Should there be any on-site interim spent fuel storage following this period then the plans for this storage facility will take account of climate change for the whole period of on-site presence.

At the site specific stage of licensing the UK HPR1000, following the GDA, specific local flooding hazard sources will be identified and assessed in detail, which includes sea level.

Further information on how the impacts of climate change are taken into account in the design of the UK HPR1000 can be found in chapters 3 and 18 of our Pre-Construction Safety Report.


Some questions have been received about how the GDA considers security, in particular cyber security threats.

Nuclear security is a fundamental part of the GDA and a key area of assessment for the UK nuclear regulators.

As part of the GDA process the Generic Security Report (GSR) is one of three key report submissions assessed by the nuclear regulators. This report includes both the physical and cyber security threats to the reactor design and buildings within GDA scope and identifies the mitigations required to manage these threats. Throughout the process the GSR is assessed by the Office for Nuclear Regulation (Civil Nuclear Security and Safeguards Division) who will only issue a DAC upon assessing that the security measures identified, and put in place through the GSR, are appropriate and fit for purpose.

More information can be found on the security pages of our website.


A few comments have been received about decommissioning of the nuclear reactor in the GDA process.

The plans for the decommissioning and spent fuel storage of the UK HPR1000 reactor have been assessed by the ONR and EA as part of the GDA process and further information on our decommissioning processes and the interim storage of spent fuel can be found in chapters 24 and 29 of our Pre-Construction Safety Report.

Furthermore, any prospective site operator for the UK HPR1000 reactor will have to provide supplementary information on the site-specific decommissioning and spent fuel management arrangements as part of the Funded Decommissioning Programme (FDP) process required by the Energy Act 2008. The FDP will include a full decommissioning plan (with timescales) and put in place legally binding commitments on the site operator to make financial provisions for decommissioning and spent fuel storage. This would include storage facilities (protected from all hazards) on the site until a national repository for spent fuel and radioactive wastes is available.

The FDP would be need to be approved by the Secretary of State for the Department for Business, Energy and Industrial Strategy in accordance with the Energy Act 2008, before power station construction could commence.

Health effects

Some comments have been received about the safety of nuclear materials in regards to the human body.

Nuclear safety is our overriding priority and is at the forefront of building and operating nuclear power stations. In the UK the independent Committee on Medical Aspects of Radiation in the Environment (COMARE) advises on the health effects of natural and man-made radiation. Its 10th report in 2005 concluded that nuclear power stations were not associated with increased cases of childhood cancer. This conclusion was re-examined in COMARE’s 14th report in 2011, which also concluded that there is no evidence to support the view that there is an increased risk of childhood leukaemia and other cancers in the vicinity of Nuclear Power Plants in Great Britain.

Since the COMARE statement in 2005 research has continued – both in the UK and internationally – and none of this research has revealed evidence that undermines the clear conclusions reached for UK nuclear power stations. We take the safety of people living around our sites very seriously and prospective radioactive discharge limits for routine discharges are set by the Environment Agency following extensive justification and assessment to ensure that they are as low as is achievable and that the best available techniques for limiting and measuring discharges are used within the UK HPR1000 design.

Additionally, the immediate areas around the sites are subject to routine environmental monitoring and this information is shared with the nuclear regulators. Our regulators at the Office for Nuclear Regulation and the Environment Agency carry out their own off-site monitoring of the UK’s power stations; their reports are available to the public on the UK Government website.

Safety of design management

A few comments have been received about how design changes will be managed. Design management and change control processes have been established as part of the GDA process. Experience from previous GDAs, and in particular the UK EPR GDA, has been taken into account when developing the processes for the UK HPR1000 GDA. A key feature is that every design change is subject to a level of review and scrutiny, which is proportionate to the safety significance of the change. The most safety significant design changes will be subject to specific review by the Office for Nuclear Regulation and the Environment Agency, but they may review any design changes they deem necessary.

Payment of GDA

One comment was received about who pays for the GDA process. The assessment and all related costs of the Generic Design Assessment, including the Environment Agency’s public consultation, are paid for by the Requesting Party (RP), i.e. the companies who have submitted a design for assessment.

Unproven technology

Comments were received that the UK HPR1000 was unproven technology. The purpose of the GDA is to allow the Nuclear Regulators to review, monitor, influence and accept safety submissions on the reactor design.

This is a well-established process and leads to safe and secure reactors, designed to UK standards.

The UK HPR1000 is a pressurised water reactor (PWR), developed from an original Westinghouse design. Pressurised water reactors are currently operating in many places around the world, such as at Sizewell B in Suffolk. The UK HPR1000 is a third generation reactor, and by the time it could be operational in the UK there will be multiple examples of it operating elsewhere in the world.


Out of scope comments

Site specific

We have received a number of site specific comments as part of the comment process. These comments are out of scope of the GDA process, which focused on the UK HPR1000 nuclear reactor technology and how it meets the UK’s standards on safety, security, environmental protection and waste management. It is not site specific, however, and a range of other consents and permissions would be required before the reactor technology could be developed at a particular site, including at Bradwell.

Site specific information can be viewed on the Bradwell B website, most notably in the Stage 1 consultation material which is available on the website.

Need for nuclear / renewables

Some comments have been received regarding the need to prioritise renewable development and nuclear policy. The principle of electricity generation and nuclear power is a matter for Government policy. More information is available on the UK Government’s website. This includes information on the national policy statement for nuclear power, regulatory justification, and waste and decommissioning arrangements amongst other things.

Cooling system

A few people have asked why the turbine cooling system design for the UK HPR1000 is different to the design for Bradwell B.

The GDA design, including the turbine cooling design, can be modified where necessary to suit site-specific needs. This approach is consistent with regulators’ expectations and guidance. Any modifications from the GDA design to site specific proposals will be fully assessed as part of the site-specific safety case by the Office for Nuclear Regulation and by the Environment Agency, notably as part of the relevant environmental permit applications.

Emergency planning

A few people have asked about emergency planning in relation to Bradwell B.

Any potential future operator of a planned power station at Bradwell will have a duty, along with the emergency services and the local authority, under the Radiation (Emergency Preparedness and Public Information) Regulations (REPPIR) to address the development of emergency arrangements as part of the development of the power station prior to operation. Given the site-specific nature of these plans they are considered out of scope of the GDA process, which focused on the generic aspects of emergency planning and preparedness within Chapter 32 of the Pre-Construction Safety Report.