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Open peer review: Prospects for Nuclear generation in Great Britain

We are keen to receive review comments for our draft report (Prospects for nuclear generation in Great Britain) which is now available for open review here.

Because some researchers are reluctant to publicly engage with us for fear that they will face hostility from campaigners and some of their peers if they do, reviewers can request anonymity, but we will need to know the identity of those who submit comments.

Submitted comments will be subject to a moderation process and will be published, provided they are substantive and not abusive.

30 August 2023: The review period for this report has now closed.


1. Prof Wade Allison

Prospects for nuclear generation in Great Britain by Kathryn Porter

The author explains the options facing the UK Government today. The work is a thorough examination of the questions it asks. If it had been written fifty, even forty, years ago it would have formed a good guide to the way ahead. Unfortunately, that is not the case. There are questions that it does not ask, the answers to which are needed if prospects are to be realised on the timescale that climate change has set.

Public opinion in the UK is not markedly anti-nuclear, but its policies and approaches are risk-averse without asking the related questions. For example, although Kathryn Porter follows the media in calling it a “disaster”, the Fukushima accident proved, dramatically and beyond doubt, that nuclear power is safe even under exceptional conditions. The same can be said of the Three Mile Island accident, and even of Chernobyl where most of the suffering was caused by the inept evacuation based on the unscientific regulations. These LNT regulations lead to over-designed and over-priced reactor designs such as EDF’s EPRs which are delayed and hard to build. These major errors of judgement in radiation safety and their consequences for nuclear power go unexplored in this document. Kathryn Porter may say that the effects of radiation on life and the social effects of radiophobia are outside her field. Unfortunately, that is true for many, but that is where the problems lie – in education and professional reach.

What does society want? The energy it needs is not available from Renewables on the scale required. If fossil fuels are to be phased out in a couple of decades, most of that energy should come from nuclear. That scale of demand is far greater than many admit and is needed worldwide on land and sea. As Kathryn Porter makes clear, there are many nuclear options that can be available in 10-20 years. That is the easy part. Educating politicians, the media, civil servants and financiers that the options are safe is a re-education exercise that should go hand-in-hand with recasting the regulations on a firm scientific basis. The President of the Health Physics Society, Dr John Cardarelli, together with 7 previous Presidents, has recently written to the US Congress to “Request for oversight investigation to ensure that the latest science is incorporated intothe radiation protection standards for low-dose environments.” The position is explained in popular terms by Lightfoot, a distinguished Canadian engineer, in a recent video

Kathryn Porter’s report is too narrow and conservative. If the UK moves slowly and ineffectively, as it has in the past, it will be overtaken by a long list of countries that are already moving, from Poland and Korea, to Estonia and India – we are late. Russia and China are way ahead, even if Australia and Germany are well behind. When the real challenge comes – popular demand following prolonged blackouts or climate-generated migration – our children will ask why we did not build earlier. Weren’t we frightened, they will say, we should have been. We need to allow the young UK engineers to invest their careers in building local SMRs and AMRs, close to where people live and work and avoiding an enlarged expensive and vulnerable grid. If we don’t use it, our skill base will go elsewhere. We need our brightest to start work now and join the international effort with a UK base.

Professor Wade Allison, Emeritus Professor of Physics and Fellow of Keble College, University of Oxford, UK

2. Andy Bush

I am a retired mechanical engineer, I specializing in oil industry maintenance and reliability.

I start with the Executive Summary which reflects the conclusion. It does not really tell us much more than provide of list the situation. It seems part criticism of the UK government, observations of so called renewables, and part a wish list.

The UK government has the reputation of being inconsistent with policies, and basing many policies on far from scientific ideas and upon many totally misconceived ones, e.g., recommending diesel cars.

May I suggest the report therefore adds a clear and precise plan for a way forward in the executive summary. An achievable and measurable plan. Possibly it would help the government to focus.

Unfortunately the report in its commendable listing of the currently seemingly jumbled UK energy mess left me seeing an assortment of thoughts which I find hard to condense into an actual set of recommendations.

Andy Bush, BSc (Hons) CEng MIMechE

3. Roger Graves

One area lacking in this otherwise comprehensive review is a section devoted to risk management. While there are a plethora of technologies and potential development areas for nuclear power, some may come to fruition while others will die on the vine. A risk management section (risk identification, risk assessment, and mitigation strategies) would be a useful tool with which to form a reasonably informed judgement about which have the best chance of coming to fruition.

Risks can occur in various forms, technical, financial, political and social. While technical and financial risk, and to a lesser extent political risk, were mentioned but not analysed to any great extent, social risk was hardly covered at all. For example, organisations such as Extinction Rebellion could potentially delay or halt completely the construction of nuclear power stations, officials sympathetic to anti-nuclear movements could effectively sabotage nuclear projects by adding unnecessary regulatory burdens, and so on.

Any plan to implement nuclear generation in Great Britain should include a comprehensive and realistic risk management plan. I would suggest that a section to indicate what such as plan would look like be added to this document, or since the current report is already quite lengthy, be written as a separate report.

Roger Graves
Ottawa, Canada

4. Clive Hambler

Although wide-ranging this important review does not cover ecological impacts and associated constraints on nuclear power.  I suggest either the title be amended to limit expectations to economic, safety and technical issues, or some content be added on ways environmental impacts may limit the prospects for nuclear power – as with any other source.

Whilst the ecological effects of nuclear power may be relatively low per unit energy (Hambler C. & Canney, S.M., 2013, Conservation, CUP) they are non-trivial and efforts should be made to minimize them – as with any power source.  There are effects at the power station site, at the waste disposal site, in the production line (eg uranium mining) and from accidents.  These effects may in theory exclude some proposed locations that are protected under international laws or under the UK’s commitments in the Convention on Biological Diversity.

Whilst the physical footprint of nuclear sites is small per unit electricity, the water intake for cooling can be massive, and this draws in and kills wildlife, some of which is critically endangered and protected (European eels, for example) or is commercially important. There is also thermal pollution in the water outflow – which could reduce oxygen levels but ironically benefit some species in some locations (as suggested for some birds in the river Severn in winter).  The potential for rewilding and re-stocking rivers may be reduced by water intakes.  

Some of these impacts could be reduced by use of cooling towers – or possibly use of the waste heat for other purposes.  This would draw less cold water and wildlife into the power station, and send less warm water back into the ocean, river or lake.  Cooling towers or other systems should be the default in the design stage, because retrofitting them could be hugely expensive;  expert advice on possible impacts of not using them should be publicly discussed.

The report could alert readers to such impacts and constraints by including reference to ecological impacts from publications such as:  Hambler & Canney, 2013;   Henderson, P.A., 2018, Ecological effects of electricity generation, storage and use, CABI.  Influential environmentalists such as Shellenberger M.D. and Monbiot G.J.R have also written on relative ecological impacts of various power sources including nuclear.

Under legal commitments to biodiversity, it is likely the ecological impacts will grow in importance and regulations might thus make cooling systems more important in environmental impact assessment and approval.

Despite these concerns, some conservationists have for decades been arguing in favour of nuclear power, and some ‘Eco-Modernists’ and environmental activists now support them.  If support for nuclear is to continue to grow, it could be a false economy to needlessly harm wildlife – particularly where the cost of a cooling system is a small fraction of the total station costs.  It would not be hard to include at least a brief introduction to such issues in this report, encouraging readers to seek more details.

Clive Hambler,  Lecturer in Biological and Human Sciences, Hertford College, and Department of Biology, University of Oxford.

5. Bryan Leyland

This paper appears to be an excellent review of the situation in the UK and current technology.

It seems to me that it would be improved by the addition of sections as follows:

Why do we need nuclear power?

Reliable, long life and, for those who believe in AGW, free of emissions of carbon dioxide.

Is it safe?

Summarise the evidence that nuclear power, is, by far, the safest major form of power generation.

Compare it with other generators including hydropower where it can be argued that large dams are the most dangerous things that mankind makes and the safety regime is inadequate.

Comment on Chernobyl, 3 mile island, and Fukushima

Is radiation dangerous?

This can be answered by Wade Allison based on his book “Radiation and reason”.

Explain that the linear no threshold model of radiation danger is without scientific support.

How do we dispose of nuclear waste?

It is not a big problem because it decays to levels where the radiation is safe in less than 1000 years (check with Wade Allison) and 6 feet of water will shield you against the radiation from a high level waste canister.

If no one goes near it, no one will get hurt

Compare it with a large dam that will require active safety monitoring and maintenance for as long as it lasts – could easily be 2000 years or more???

Comment on the regulatory regime

Based in the past where each nuclear reactor was an improvement on the last one and needed a thorough scrutiny. Also based on a belief that all radiation is dangerous rather than the fact that low levels of radiation (certainly up to 1000 mSv) are harmless. Modern practice is to refine a design and then make identical repeats. This is certainly true with small modular reactors. This needs a streamlined regime that licenses a design and also accepts that low levels of radiation are not dangerous.

How is it that the Russians and the Chinese (and others) seem to be designing and building new reactors successfully?

What do we need to learn from them?

Bryan Leyland

New Zealand

6. David Turver

First, can I congratulate Kathryn on wading through so many Government documents. I know from personal experience just how time consuming that is.
I think it is worth spelling out more explicitly the chasm between the Government’s stated plans for nuclear capacity (24GW) and NG ESO’s assumed 10-16GW. That translates into big TWh-scale differences in the amount of energy we will get from them.  This is especially important as in the latest FES report they seems to regard more than 16GW of reliable baseload as an inconvenience to the Heath-Robinson grid they are designing.
An extra point is that although the Government and NG ESO think we will be generating much more electricity by 2050, overall total energy consumption for I&C, Domestic and Transport falls dramatically, and even further in per capita terms (up to 60% depending upon scenario). This is creating an energy scarce world and as I am sure you already know, there are no rich countries with low per capita energy use. In effect, they are planning for energy scarcity and so there is an inherent “energy gap” in their plans. This energy gap also represents an opportunity (I would say a necessity) for nuclear to fill.
In the section on potential nuclear technologies we could use, I would add the Korean design recently completed at Barakah and not too far over budget. OECD puts Korea as the cheapest developer of new nukes, well below France (EPR) and USA (Westinghouse). In the link, I also go through ideas of how to bring down costs. Cost of capital is a major impediment that could be solved by RAB or something similar. I don’t think it’s credible for the Government to put such a large programme on its own balance sheet, although it would add more value than HS2, but that’s a different argument.
Personally, I wouldn’t devote so much space to fusion at this stage, it just confuses matters. It was a promising technology 30 years away from commercialisation when I was an undergraduate engineer 35 years ago. Sadly, it still is. Its promise makes it worthwhile as a research subject, but we can’t rely on it to be delivering anything by 2050.
It might be helpful to add a short section on recent developments in Japan, China, India, Middle East, France, Belgium, Netherlands, Canada and US to illustrate how other countries are embracing nuclear power through life extensions to existing plants or announcements of new builds. For instance, China is building 150GW of new capacity by 2035, roughly quadrupling their existing fleet.
Maybe also adding something on how nuclear power fares compared to other technologies on a range of sustainability measures. It’s much better than wind or solar on most things.

David Turver 

7. Malcolm Grimston


This paper covers a great deal of ground in a fair and objective way. However, in this author’s opinion it would benefit by drawing distinctions between technology available ‘now’ (i.e. up to about 2035), technologies likely to become available between 2035 and 2050 and those which could be available post 2050. Different considerations and policy responses affect these different timescales. Further, in all scenarios, moving to a rational and proportionate regulatory system will be vital to fulfilling nuclear power’s potential.

OVERVIEW – a framework for the paper’s arguments.

The following points are central to the debate around future nuclear energy in Great Britain.

  1. Nuclear plants are both low carbon and dispatchable; further, their high power density minimises local environmental consequences and fits well within the UK grid which, like other supergrids, has evolved to serve large point sources of generation.
  2. Development of new nuclear capacity is now extremely urgent, given the imminent closure of the remaining AGRs and the likely increase in power demand as further sectors of the economy  become electrified (e.g. private transportation).
  3. Funding nuclear power requires considerable government involvement; there are various models ranging from direct state funding to various market approaches but in all cases the critical issue is managing the construction risk and this cannot be done purely by the private sector.
  4. The costs involved in setting up a supply chain are considerable and may only be provided if there is a high degree of confidence in multiple orders. The UK market is probably not big enough to sustain several different large (GW+) LWR (Light Water Reactor) designs all under construction within similar timeframes – the Magnox and AGR programme both suffered significantly from the failure to standardise designs.
  5. Regulation must be reformed to ensure that the costs, timescales and uncertainties of gaining a plant license do not act as a major deterrent to investment and drag on how quickly that investment yields electrical output. In particular, once a design has a license in its country of origin or another trusted country, GDA should be very limited process.


The paper does rightly refer to low carbon, reliable nature of nuclear output. However, relatively little discussion is offered on why nuclear power looks more attractive than alternative low-carbon technologies, notably renewables with storage, or to challenge the increasingly meaningless metric of ‘Levelised Cost of Energy’ in a world of increasing renewable penetration when for growing periods of time electricity becomes a good of negative value owing to renewables swamping the system. An opening review of where we are with energy (electricity in particular), the challenges and the pros and cons of various possible responses would be fruitful.


The paper acknowledges the urgency of the situation in the UK at present. Most of the present civil nuclear capacity is expected to be offline by 2030.

However, the paper, by discussing in quite an indiscriminate manner technology that is presently under construction; technology that may mature in the 2030s or 2040s; and even more than two pages on fusion (unlikely to be commercially available before the 2050s), risks undermining this urgency. It may be better to divide ‘the future’ into three periods:

  • ‘the immediate future’, up to perhaps 2035;
  • ‘the mid-term’ (2035-2050);
  • the long-term (2050 onwards).

In the ‘immediate future’, a failure to replace present nuclear capacity as soon as possible after its end of life is important for many reasons, as the paper covers. For example, the intermittency of wind and solar makes grid management much more difficult in the absence of baseload nuclear output, creating the dual challenges of providing enough gas-fired capacity to manage periods of low renewable output yet having to compensate these plants for period of high renewable output. Similarly, the grid requirements to wire up in effect a second power system based on distributed renewables while maintaining one based on large (fossil) point sources will be costly, slow and meet considerable public and environmentalist opposition. Further, the longer the gap between closure of AGRs and grid connection of their successors,

The only option available within this time period is to order perhaps two further large-scale reactors in addition to Sizewell C. Assuming that the Chinese technology is (at least for the moment) unattractive for political reasons and while it may be possible to create a supply chain for APRs (as there is recent global experience of the design), prima facie in practice it would be much simpler to order further EPRs to take advantage of the existing infrastructure (while noting the fair comments in the text about recent European experience of project managing such installations).

The paper does a service in listing no fewer than 8 government initiatives just since 2020 which, cumulatively, have as yet not delivered anything close to a new nuclear project. The need for firm and focussed action is crucial.

For the medium term the options are wider but less clear. While it would be a mistake to regard SMRs as entirely speculative, so too would is it premature to assume too much about which technologies will prove most attractive and what their ‘final’ economics will look like. It may be of limited value at this stage to focus too much on particular technical options at this stage as the focus should be to press government to put into practice the words around SMRs which, as the paper notes, have been in government publications since at least 2014. Further, for mature grids the attractiveness of large point sources of power, as represented by GW+ scale ‘traditional’ nuclear technology, willer main high, as evidenced by the number of such reactors under construction today which would be expected to operate for most of the rest of this century, if not longer. HTRs, smallscale FRs, molten salt reactors, thorium and others – all are unlikely to be available to address the present and urgent challenges of AGR closure and indeed some might be better regarded as ‘long-term’.

For fusion and other post-2050 technologies (indeed one can argue fusion is as different from fission as fission is from coal) the present task is to make the case for global collaboration on the basic engineering principles; again it is probably fruitless to spend too much time second-guessing what mature fusion would look like given the relatively recent demonstration of the basic scientific task of ‘ignition’. Focusing too much on these quite distant technologies risks diverting attention away from the immediacy of the challenge of imminent closure of the AGRs.


The paper is rightly very clear that the economic risks of nuclear power – in short, that compared to other power options, much more of the cost of nuclear generation is front-loaded in the construction phase, so managing risks of cost or schedule overruns is a practically insuperable task for private capital – are such that heavy state involvement, probably up to and including direct state investment in new nuclear construction, is unavoidable. The paper is also probably right in saying that the CfD/strike price structure which was created to fund Hinkley Point C probably will not be repeated, though it should be noted that CfDs are not just a floor but also a ceiling on income and that, with wholesale prices at levels seen in recent months, Hinkley Point C, had it been operating, would have been paying back considerable sums to electricity consumers – for example, in the last three months of 2022 the ‘season ahead’ prices for winter 2023 were hovering around the £300-£350/MWh mark, well above the Hinkley Point C strike price of around £110/MWh at the time. RAB seems to be the latest attempt to apportion construction risk in such a way that the price is manageable but the risk does not entirely fall on consumers (an honourable aim) but it is yet to be seen if it will be sufficiently attractive to stimulate private sector (or rather non-UK government sector) investment. The paper notes the near-obsession with keeping nuclear investment off the national books but, as seen with PFI in the 2000s, there is no guarantee that this gives the best value.


The disappointing record of the first EPR construction projects is rightly discussed in the paper. However, the paper’s suggestion that ABWRs be considered based on just four completed projects (which came on line between 1996 and 2006) which were built rapidly (39-43 months) in Japan does not address the inevitable time it would take to establish in effect an entirely fresh supply chain. The case for the Westinghouse AP1000, recently chosen for example by Poland, is perhaps stronger as there is recent global experience (though again not without problems, as the paper notes); the South Korean AP-1400 design has also been successfully built in the UAE in recent years. However, the benefit of a fully formed supply EPR chain should not be underestimated.

Experience in France and Sweden in the 1970s/1980s and in China recently shows that nuclear power can be built very rapidly when the circumstances are right. Constructing a series of plants to similar designs underpinned the French nuclear success of the 1970s; the UK by contrast in effect built a series of prototypes in both the Magnox and AGR programmes and therefore suffered from a lack of both series economies of scale and learning curve effects.

One would expect SMRs to be manufactured offsite and assembled on location, leading to lower costs in both construction and decommissioning.


It is very clear that what can be portrayed as over-regulation of the industry, compared with its competitors, has had an enormous detrimental effect on nuclear investment in recent decades. A report in MIT Technology Review this February, for example, says: “NuScale started working toward regulatory approval [for its SMR design] in 2008 and submitted its official application to the NRC in 2016. In 2020, when it received a design approval for its reactor, the company said the regulatory process had cost half a billion dollars and that it had provided about 2 million pages of supporting documents to the NRC.”[1] This issue is hardly addressed in the paper – there is a reference to the comment in the British Energy Security Strategy to a desire to “work with regulators to explore the potential … for streamlining or removing duplication from the consenting and licensing process for new nuclear power stations” but no discussion as to how this could and should best be achieved. The regulatory regime will be a crucial factor in the prospects for nuclear generation in Great Britian and elsewhere; the need to move towards more of an ‘aircraft industry’ approach where global licences are issued to designs which are approved in their country of origin (assuming confidence in the initial licensing process) without individual countries and individual projects being required to ‘reinvent the wheel’ deserves considerable attention, perhaps more so than the minutiae of some of the speculative designs which are presently emerging.