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Common comment themes


As part of the GDA process we have invited members of the public and interested parties to comment on the reactor design information and the formal regulatory submissions. We have summarised some of the common comment themes we have received as part of the GDA comments process so far and our responses.  These have been ordered below in terms of frequency the comments have been made.

We have received a number of comments which are out of scope of the GDA process. The GDA process does not cover nuclear policy and principles, nor does 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 are accepted, reviewed and redirected if required.

You can continue to submit a comment as part of the GDA process. We consider all relevant comments and seek to respond within 30 days.

Technical comments and questions

We have 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 for the safety systems, use demineralised water produced using freshwater from a third party townswater supplier.  Sea water would be used in cooling systems associated with the turbine/generator 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.

Chinese and French involvement

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

CGN and EDF have created a joint venture company, called General Nuclear System Limited, to undertake the GDA process for the UK HPR1000 nuclear reactor technology.

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.

The CGN fleet has 20 operating reactors with 30 years of experience and in 2016 had 43 performance indicators in the top 10% of the world (WANO data). EDF in turn currently operates 58 reactors in France, and 15 in the UK. The two companies have successfully worked together for more than 30 years.

Nuclear waste and spent fuel

A number of comments have been received about the storage and management of 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 Pressurized Water Reactors.  The nuclear power industry takes full responsibility for all of its waste, unlike other forms of power generation.  The amount of waste generated is also relatively small.  For example, a coal power station typically produces 300,000 tonnes of ash in a year whereas a nuclear power station only produces 30 tonnes of solid waste.

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

The activities involved in managing spent fuel and radioactive waste are now well understood.  The funds required to decommission the power station, including long term management of the spent fuel and radioactive waste, will be set aside during the operational period of the power station, as required by government legislation (Section 45 of the Energy Act 2008).  The costs of this will therefore not fall onto future generations. 

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.

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 (this period is still being defined, and will be confirmed as part of the funded decommissioning plan). 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.

During GDA a generic assessment is made of external flooding hazards which assumes flood water above the nuclear platform level.  This assessment is extremely conservative and is intended to demonstrate the robustness of the UK HPR1000 design to external flooding sources. 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 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 to secure Design Acceptance Confirmation (DAC) and Statements of Design Acceptability (SoDA). This report includes both the physical and cyber threat to the reactor design and buildings within GDA scope and identifies the mitigations required. 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 assurance 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 in the GDA process.

Decommissioning and spent fuel storage is the subject of another government process: the Funded Decommissioning Plan (FDP) process. The FDP will include a full decommissioning plan (with timescales) and put in place legally binding commitments on the operator/site licensee to make financial provisions for decommissioning and spent fuel storage. This would include storage facilities (protected from hazards) on the site until a national repository is available.

The FDP would be developed and signed by the Secretary of State, before power station construction would start. It will use conservative assumptions to give confidence that enough financial provision will be made for both decommissioning and storage.

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.

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. 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 cancer.

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.  The perimeter fences around nuclear sites have extremely sensitive monitoring systems that would detect very low levels of airborne radiation. 

Additionally, the immediate areas around the sites are routinely monitored 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 Environment Agency’s 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. 


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. The focus of the GDA is the UK HPR1000 nuclear reactor technology, and how it meets the UK’s standards on safety, security, environmental protection and waste management.  It is a generic process that, if successful, would enable the reactor to be built and operated in the UK.  It is not site specific, however, and a range of other consents and permissions would be required before it 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 website.  This includes information on the national policy statement for nuclear, regulatory justification and waste and decommissioning arrangements amongst other things.

Cooling system

A few people have asked why the cooling system design for the UK HRP1000 is different to the design for Bradwell B.

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

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.