Preparedness and
Response for a
Nuclear or Radiological
Emergency Involving
the Transport of
Radioactive Material

Transport packages are designed with a graded approach, meaning that the higher activity and more mobile forms of radioactivity get transported in more robust containers. This is designed to ensure that most emergencies during transport have limited radiological consequences and can be resolved in a relatively short period. However, there are always the low probability, high consequence accidents to keep us awake.

The objective of this publication is to provide recommendations on emergency preparedness and response for the transport of radioactive material. These recommendations form the basis of achieving the goals of emergency response described in GSR Part 7.

The recommendations in this Safety Guide are aimed at States, regulatory bodies and response organizations, including consignors, carriers and consignees.

Section 2 covers national arrangements which should integrate and coordinate the capabilities of responders and ensure that their roles and responsibilities are clearly specified and understood.

“The government shall make adequate preparations to anticipate, prepare for, respond to and recover from a nuclear or radiological emergency at the operating organization, local, regional and national levels, and also, as appropriate, at the international level.”

There is a lot of detail, 14 pages of it, including a description of what the consignor’s and carrier’s plan should contain (para 2.57). These are not a-plan-on-a-page.

Section 3 is about preparedness and response. It talks about a concept of operations as “a brief description of an ideal response to a postulated emergency, used to ensure that all the personnel and organizations involved in the development of emergency response capabilities share a common understanding”. It also discusses the objectives to consider.

The report then goes through the urgent response phase where those on the scene and first responders are determining the situation and, in particular, looking for evidence of failure of containment or shielding and acting accordingly. It gives an aide-memoir for reporting the situation (3.14), the priorities for response (3.19) and protective actions to consider (3.30).

A transition to either a planned exposure situation or an existing exposure situation, depending on the circumstances might be required if the environment is contaminated. We are told that “the transition phase commences as early as possible once the source has been brought under control and the situation is stable; the transition phase ends when all the necessary prerequisites for terminating the emergency (these are given in 3.34) have been met” (3.38).

There is a section on Training, Drills and Exercises (3.43 – 3.53).

Section 4 focuses on road, rail, sea, inland waterway and air in turn, talking about how and why these modes are used and any special features to consider.

Section 5 looks at transport events initiated by nuclear security events and the extra considerations put into play, including the requirements for crime scene preservation.

Appendices give advice on (1) developing national capability and (2) types of events that might lead to a transport emergency (useful for setting scenarios).

Annex 1 reviews IAEA advice on transport regulations, including classification, signage and packages.

Annex 2 is a model event notification form.

Annex 3 is a template carrier or consignor emergency response plan.

Annex 4 provides 7 scenarios to consider.


The ONR have a considerable body of reference material relating to the transport of radioactive material which can be found at

This includes guidance on risk assessment under IRR-17 and Guidance on emergency planning and notification for the transport of class 7 goods

This states that “CDG09(19) require duty holders (both the consignor and the carrier) to have a plan where they have reached the conclusion that a radiation emergency might occur. The emergency plan must detail the arrangements to restrict, so far as is reasonably practicable, the radiation exposure of any person that may be affected by a radiation emergency before the carriage of radioactive material takes place. This includes the vehicle crew, the public, attending emergency services and any persons exposed to ionising radiation as a result of a loss of radiation shielding, release of all or part of the contents of a package or an uncontrolled criticality when transporting radioactive material”.

It also notes that “Provision of information in the event of an emergency to those likely to be affected is placed on local authorities through Regulation 22 of REPPIR19.”

In their November 2020 document Five Steps to Transport Emergency Planning ONR outline five steps:

  1. Evaluate whether an Emergency Plan is required
  2. Preparing an Emergency Plan
  3. Test, Review and Revise the Emergency Plan
  4. Implementing the Emergency Plan
  5. reporting requirements after an emergency

NAO on the decommissioning of the AGRs

I think that this report by the National Audit Office (NAO) is quite worrying. It seems that the only thing we know about the defuelling and decommissioning of the AGR sites is that it will cost a lot of money; almost certainly more than has been put aside for the job.

The current agreement is that as soon as EDF declare a station off the bars permanently the costs of the site transfers to the decommissioning fund, EDF are paid to defuel the site and then ownership “of all land, assets and contracts required by Magnox Ltd to commence (commence not finish!) deconstruction on the sites” transfers to the NDA i.e. it seems that EDF can maybe choose to retain the assets they fancy.

EDF estimated that the fixed costs to manage and maintain a station that is not generating electricity but still holds fuel are around £140 million per station per year, compared with around £25 million to £35 million per station per year once the fuel has been removed. It does, of course, remain to be seen how realistic these values are.

The NDA will not know the exact details of what will transfer nor have a full understanding of the associated costs and liabilities until closer to the expected transfer. The long-term success of this scheme then depends on the ability of the NDA to deliver efficiencies from combining the AGR stations with the existing portfolio. Not that they have an unblemished history.

Since 2021 the NDA has adopted what it terms a rolling decommissioning strategy for its Magnox stations. This approach, it believes, could allow reactors to be decommissioned sooner. Stakeholders the NAO spoke to with technical expertise and knowledge of the AGR stations expressed differing views on the applicability of a rolling strategy to the AGR fleet.

I find it worrying that the way in which EDF, NDA and Magnox Ltd will work together to plan for transfer of the stations is set out in a Memorandum of Understanding because they could not agree the terms of a legally binding agreement. Meanwhile the Department is reliant on there being continuing goodwill between EDF and the NDA to resolve potential differences.

The UK government has yet to put in place arrangements by which it can assure itself that the Department is fulfilling these roles and the decommissioning programme is performing effectively.

Finally, what does the statement that it should be possible to save £1 billion in an estimated cost range of £3.1 billion to £8.0 billion mean? Surely you save £4.9 billion by hitting the lower estimate rather than the higher.

Should we evacuate elderly people in a nuclear or radiological accident?

There is an interesting talk on the ICRP’s ICRP Digital Workshop: The Future of RP by Jessica Callen-Kovtunova entitled Making ICRP Recommendations ‘Fit for Purpose’ for the Response to a Nuclear or Radiological Emergency.

In this she reports a meta-analysis of 600+ papers which reviewed the impact of protective actions and claims that for every 1000 people evacuated we may expect 7 deaths among the general public due to dislocations caused by the protective action and between 15 and 117 among residents of facilities for long stays and the elderly as well as between 120 – 220 mental health problems.

They compare this to 5 deaths prevented by evacuating 1000 people with an averted dose of 100 mSv each (this appears to be based on the ICRP-103 approximation of the overall fatal risk coefficient of 5% per sievert).

They conclude that: “Taking protective actions consistent with dose criteria used in many countries could result in far more excess deaths than hypothetical excess radiation-induced deaths prevented.  We must include these effects to protect people effectively.”

If we agree with these findings, and before doing that I’d like a closer look at the applicability of the evidence, we must ensure that the current ERL for evacuation is reconsidered and its application to homes for the elderly, in particular, given very careful thought.

If we start to think about different protective action thresholds for different age groups maybe we could also consider stopping planning to give those over 40 -50 years old stable iodine.

The potential for remote inspection in the nuclear industry – Webinar

I’ve just listened to a Webinar “How to Implement Remote Inspection in the Nuclear Energy Sector?” organised by TUV SUD (I’m not sure about the question mark!).

It introduced the idea that one person could “walk the site” wearing smart glasses, while their colleagues watch from a remote location, request the walker stop to look at anything that catches their attention and ask questions through the walker. If accepted, this could complete an inspection with fewer on-site resources and will generate an audio-visual record of the inspection from which the report and conclusions can be written.

I’m not sure this is a particularly new concept; the nuclear industry, and probably others, use remote monitoring to support operators working in difficult areas where there is a balance between having all the skills and expertise to hand and minimising the size of entry teams. The use of smart glasses may be new and maybe adds another option to body worn cameras and infrastructure mounted cameras. The application to teams of off-site inspectors may be novel. The service offered seems to be the full sweep of technology, hardware and software, from the camera to the remote inspectors; with the lessons of experience and training offered as well. This may well be a unique service for the time being but barriers to entry are probably not high.

There were several questions to do with broadband signal, band width, data protection, cyber security and safety with the conclusion that this technique is well within current technical capabilities. It has been used maybe 10 -20 times in Europe and about 50 times in China.

This is an interesting concept and an area that is likely to develop in future. Why send a team of people to a remote site and then into an industrial or contaminated environment when you can send one person, or a robot?

The regulators would have to consider the qualifications and experience required of the on-site inspector, who would be much more than just a camera operator, and the conduct of any such inspection. The industry could consider if the technology has application in normal operations and accident response that adds to the capability already offered by site sensors, including cameras, and body worn cameras that they already use.


Impressions of the Emergency Services Show 2021

I attended the Emergency Services Show yesterday (7/9/21). As in the past this offers access to a large number of exhibitors and a range of short presentations.  I don’t plan my visit very well and just wondered up and down hoping to find all the interesting stalls. This meant I stopped and chatted to random people rather than worked down a list and that this review is therefore rather random.

Themes include vehicles and vehicle fittings, lights (lots of LEDs!), care for responders physical and mental wellbeing, cameras on drones, people, vehicles and poles, more drones with different capabilities, handheld devices to detect and measure threats, PPE & RPE and command and control systems, kit bags, ropes, pulleys etc.

There were several IT systems that allow you to integrate information feeds from cameras and other sensors dotted around the incident, radio messages from those on the ground and geographic knowledge. I didn’t take a close at these but now wish I’d spoken to someone about them. My concern (from a far!) with these is that they disrupt the information pyramid. You need a new team of people to sift through the information and identify what is important and what is changing. Having a sit-rep from the commander on the ground available to all to listen to when they wish is great, but how do you ensure that people are not still interpreting it as hot news long after it has been superseded? Having the reports of all the people on the ground, and all the videos, is also great but again come with a time cost if everybody stops to hear them. Will the remote Gold Commanders be tempted to take time to look at the video feeds and make their own situation analysis, by passing the Command structure on the ground? Is that always good, always bad or does it depend?

There were several immersive training environments, including VR sets and tents with scenes projected onto all the surfaces. These must be helpful in certain circumstances.

Handheld radiation monitors continue to develop with new crystal materials, larger crystals and, more importantly, much more on-board computing capability. Southern Scientific were showing CBRNe handhelds while kromek were showing a range of handheld and wearable gamma and neutron detectors with Bluetooth and USB comms, including some with the ability to identify isotopes. I find some of the claims a little hard to believe but these companies have happy customers whose expertise and judgement in these matters I’d place ahead of mine.

There are also a number of training tools that are realistic looking handhelds, such as those offered by Argon Electronics, that report injected exercise data rather than live readings. Obviously potentially useful.

It was interesting to talk to the people at the Defence and Security Accelerator (DASA) stand. This organisation tries to find innovations that can be exploited by the UK defence and security services and help with their development. They do this by a combination regional “innovation partners”, who provide advice to organisations and individuals about the potential merits of their ideas and how best to develop them and through more focussed “competitions” to cover identified needs. Funds are available for promising technologies at different stages of development and for the full range of company size. Their website has interesting case studies.

A car sized fire blanket from Fire Hosetech caught my attention. This is designed to manage lithium-ion battery fires which must be contained until they burn out. These reusable blankets can withstand temperatures up to 1,600 degC and reduce the spread of toxic fumes and contamination.

I also stopped to look at Fortress Distribution’s attempt to reduce the world’s usage of disposable shoe covers with plastic “Yuleys” which you step into and out of in a hands-free manner. Their design use seems to be for trades working indoors and out to prevent treading dirt inside but I wondered if they could replace single use shoe covers in contaminated areas. One issue being that they cover the sole of the shoe and the sides to a certain extent but not the top which I suspect is an idea killer. The other questions would include how much work was involved keeping them clean and how many reuses would be required to cover their own environmental costs?

Also worthy of a mention is the National Emergency Services Museum in Sheffield which showed a few of its vehicles. Got to be worth a visit if in the area.

The Emergency Services Show is well worth a visit by emergency planning and response professionals although it is not focussed on us. It gives an opportunity to see how the Emergency Services, with whom we work, are developing and an opportunity to keep an eye on technology developments and themes.

Small Modular Reactors and Advanced Modular Reactors – State of Play

The trajectory taken by mainstream nuclear power reactors over the years has tended towards more powerful units with ever more layers of backup safety systems. These are complex and therefore difficult to build and eye-wateringly expensive (Hinkley Point C costs have risen from £18bn in 2016 to £22bn – £23bn in 2021). There have been several attempts to simplify nuclear power designs by introducing passive safety and reducing the lengths of pipes and number of systems.

The concept of the Small Modular Reactors (SMR) has a long history. In the UK the Safe Integral Reactor (SIR) proposed by Rolls Royce in the 1980s and 90s used PWR technology but with reduced size and the steam generator inside the main pressure vessel. This reduces the lengths of vulnerable primary circuit pipes and other external components which greatly reduces the chances of a loss of cooling accident. It also provides more effective decay heat removal by natural circulation leading to improved safety at reduced cost and complexity. Several other SMR designs were proposed at about this time (see ASME Symposium 2011).

Picking winners? In 2016 a report written for the UK government (SMR Techno-Economic Assessment Project 3 – SMRs: Emerging Technology) reviewed over 40 SMR concepts in 6 technology groups looking for those that could be deployed by around 2030 and contribute to the UK’s 2050 decarbonisation commitment. An important conclusion was that “A combination of a lack of technical maturity, together with the likely time and effort for licensing and deployment indicates that all Emerging Technologies except SM-HTGR are at least significantly challenged on ‘Time and Cost to Deployment’ relative to SM-PWRs”. This begs the question “is the UK in danger of missing a better long-term solution by placing undue emphasis on short deployment targets?”

At about the same time another report looked at Micro Nuclear Reactors (typically under 30 MW electrical) and concluded that there were no great technical barriers to their development and that the finances looked good. It suggested that two barriers existing were uncertainly in how the regulatory process will apply to such reactors and uncertainty in long term political commitment to manage a predictable nuclear industry environment.

It was concluded that Small Modular PWRs represent the least cost generation option for SMR technologies in the short or medium term. That these can provide low grade heat for district heating and some industrial processes was seen as an advantage despite no market penetration for UK nuclear in these areas. It was also concluded that emerging technologies, particularly the Small Modular – High Temperature Gas-cooled Reactor, could offer other advantages in UK energy futures where high temperature process heat is used directly to decarbonise industrial and/or transport activities. It appears that the government accepted these conclusions.

A RR SMR brochure (2017) claimed that “A Small Modular Reactor (SMR) programme represents a once in a lifetime opportunity for UK nuclear companies to design, manufacture and build next generation reactors to meet the UK’s energy needs”. They promised SMRs providing 220 MW to 440 MW, cheaper per MW than large scale reactors, low technical risk, high fraction of UK content, 1/10th the land requirement, running by 2028.

The brochure listed a several conditions that would be required:

Condition Apparent progress (my judgement!)
Selection of one preferred technology HM Government have confirmed that they will support SM-PWR and SM-HTGR.
A UK industrial policy that supports UK intellectual property, advanced manufacturing and long-term high value jobs in the UK Difficult to assess but the recent purchase by the Government of Sheffield Forgemasters is a good sign.
Match funding until the end of the Critical Design Review It seems that funding has now been achieved to complete the GDA process.
A Generic Design Assessment (GDA) slot to ensure the process of licensing GDA is now open to SMR and AMR designs.
A suitable site to develop a First of a Kind (FOAK) power station There seems to be a view that the FOAK SM-PWR will be built on a previous nuclear power site which seems sensible.
A policy supporting a UK electricity market of at least 7 GWe for SMRs Current declared strategy looks to demonstrator (FOAK) rather than fleet. We do not yet have a declared siting and policy framework.
Export support to reach international markets Too soon to say


They don’t seem to tackle the issue of who would pay for them to be built after the FOAK, who would own them, who would operate them and how they would all be paid. RR want to build and sell 7 GW electrical, they don’t want to own and operate them.

A World Nuclear Association (WNA) report (2021) discusses an aspiration for a worldwide nuclear environment where internationally accepted standardized reactor designs can be deployed without major design changes. It reports a range of different SMR designs and a wide variety of licensing processes and diversity of overall national regulatory structures. It concluded that a country’s regulatory framework is generally either heavily prescriptive and rule-driven (such as the USA) or goal- or risk-driven (such as the UK); some are a combination of both. The report seems to hold out little hope for international approval but it does provide advice on best practice on licensing reactor designs in other host countries.

A later WNA webinar about streamlining the licensing of Small Modular Reactors again spoke of the potential gains for vendors from an international approvals system but offered few ideas on how that might be achieved.

The UK Government Ten Point Plan for a Green Industrial Revolution (November 2020) suggested that the UK electricity system could double in size by 2050 as demand for low-carbon electricity in sectors such as heat and transport rises. It looked to large scale nuclear to contribute and promised to look at the future of SMR and AMRs and invest where appropriate.

A Government Energy White paper (December 2020) states that “Nuclear power provides a reliable source of low-carbon electricity. We are pursuing large-scale nuclear, whilst also looking to the future of nuclear power in the UK through further investment in Small Modular Reactors and Advanced Modular Reactors.” It reports an aim to bring at least one large-scale nuclear project to the point of Final Investment Decision by the end of this parliament (it seems to be running out of viable options with Sizewell C being based on the hard-to-build EPR, Wylfa Newydd and Moorside inactive and Bradwell B embroiled in international politics).

The White Paper also promised that “We will provide up to £385 million in an Advanced Nuclear Fund for the next generation of nuclear technology aiming, by the early 2030s, to develop a Small Modular Reactor (SMR) design and to build an Advanced Modular Reactor (AMR) demonstrator”.

The UK government has opened the Generic Design Assessment (GDA) to Advanced Nuclear Technologies and the ONR released new guidance on the process.

A public dialogue was held in early 2021 to “inform future policy development and engagement with the public”. The output does not seem to be available yet.

The UK Research and Innovation Low-cost nuclear challenge (24th May 2021) aims to develop a compact, standardised nuclear power station product based on the Rolls-Royce led SMR. It has ear-marked £215 million investment from the UK government, to be matched with £300 million investment from industry (19/11/20) with Tom Samson, the CEO of the UK SMR consortium promising “We will continue our current work and then move seamlessly into our next phase in May 2021 beyond which we can begin creating 40,000 high quality jobs, £52 billion of value to the UK economy; and targeting the £250 billion in exports”.

The government has also sought views on the potential of high temperature gas cooled reactors with the aim to have a demonstrator by the early 2030s asking if people think they have a role in the net zero CO2 target, if there is further evidence they are unaware of and how well the UK supply chain could support the programme.

A report written by the University of Manchester, Dalton Nuclear Institute supports the development of a demonstration HTGR and suggests adding hydrogen generation to the aspirations for the demonstrator. It also recommends a suitable body that is equipped and empowered to deliver the HTGR project be constituted. This, it suggests, should be complemented by an independent body “unconflicted by claims and lobbying by any particular system proposer” to maintain an ongoing UK view of developments in AMR systems, a broad-based advisory body offering the government advice on the nuclear programme.

Meanwhile Canada has a comprehensive Small Modular Reactor Action Plan resulting from a pan-Canadian effort bringing together key enablers from across Canada including the federal government, provinces and territories, Indigenous Peoples and communities, power utilities, industry, innovators, laboratories, academia, and civil society”. It comes with a statement of principles, 117 chapters written by participants and 513 tracked actions each linked back to the recommendations made in an earlier roadmap document. This is a credible programme.

In Russia Small Modular Reactors are being built for icebreakers, for floating power plant and for land-based systems. They have the KLT-40S Integral PWR which has been evolved into the RITM-200 which is smaller and lighter. This has several variants for land and floating applications (the floating applications include providing propulsion for icebreakers and providing electricity and heat for coastal communities). There are proposals for a land-based SMR at Yakutia in the Russian Far East.

China has started to build an ACP100 SMR demonstration project at the Changjiang nuclear power site in Hainan. Designed for electricity production, heating, steam production or seawater desalination the 125 MWe PWR. The plan envisages sites with 2 to 6 ACP100 reactors with a 60-year lifespan and 24-month refuelling. A floating version is also planned.

In the US NuScale power are planning to build a 6 unit site for the Utah Associated Municipal Power Systems (UAMPS) (down from the 12 units originally planned).  The first module is scheduled to be operational in 2029, and the full plant in 2030. Meanwhile funding is being collected to build a demonstration Natrium reactor in Wyoming on the site of a retiring coal power station. This is a sodium cooled fast reactor with a thermal storage device allowing load following, including electrical outputs rates higher than the reactor’s power output for periods of time.

France has announced another new SM-PWR design, the “NUWARD”TM, while saying that they are “open to international cooperation, notably to foster the harmonisation of regulation, the standardisation of design and design optimisation”. (If that really was the case then why didn’t they join an existing project rather than develop their own?).

Japan is reported to be interested in developing and deploying SMR and AMR. Their aspiration is for a SMR demonstration site by 2030 and the establishment of the technology to use high temperature reactors to generate hydrogen.

This is clearly an interesting time for Small and Advanced Modular Reactors. They are being built in Russia and China, both of which see a good market. They are being developed in the USA, Canada, the UK and several other countries, seemingly with coherent government support. They are seen as an affordable route into the nuclear industry providing an opportunity to decarbonise the energy market and reduce dependence on imported fuels. We need to see continuing progress on the design and licensing of this technology, demonstrator sites for those that have not got there yet and a siting policy, financial model and operating regime that enables the full market potential to be realised. Meanwhile we can expect to see many of the systems currently under development to fall by the wayside.

The NEI Small and Advanced Reactors event (4th November 2021) will be a follow up to their virtual event held in February 2021. It will look at the development plans and licensing activities for a range of small and advanced reactor technologies from across the world. It will cover all aspects of industry, with insight from reactor developers, utilities, regulators, supply chain, academics and the financial community with sessions covering market development, manufacturing and construction, the utility view of the role of SMR/AMR, finance and economics, Fuel and progress towards demonstration plant and beyond. One to watch.



IAEA Technology Roadmap for Small Modular Reactor Deployment

IAEA Nuclear Energy Series, No. NR‑T‑1.1

Technology Roadmap for Small Modular Reactor Deployment

We hear a lot about the potential for Small Modular Reactors, Advanced Modular Reactors and microreactors to provide reliable, affordable, low carbon energy to produce electricity, district heat, industrial heat and hydrogen, including in places where grids cannot reach but, other than in China and Russia where they are getting on with the job, generally the discussion is about getting to the demonstrator (or First of a Kind (FOAK)) rather than beyond.

The stated objective of this paper by the IAEA, drafted by an international group over a series of meetings, “is to present several model technology roadmaps to Member States which can be adapted to their specific projects”. The guidance “describing good practices, represents expert opinion but does not constitute recommendations made on the basis of a consensus of Member States”. It is notable that no one from RR, ONR or BEIS was on this group.

The authors keep interrupting the narrative about how to plan for the deployment of SMRs with seemingly random sections reviewing the state of play with various designs across the world and the history of the field.

The paper is apparently aimed at:

  • owners/operating organizations, who drive the demand and requirements for reactor designs;
  • designers, who develop the technologies; and
  • regulators, who establish and maintain the regulatory requirements that need to be met by owners/operating organizations.

Technology roadmaps, we are told, “are part of a methodology that guarantees the alignment of investments in technology and the development of new capabilities. A proven management tool, technology roadmaps are used for identifying, evaluating, communicating and promoting the development of complex technology projects”. One aim is to increase the chances of passing well known pitfalls where failure is more likely (Figure from IAEA NR-T-1.18).

The first pitfall is the potential failure of the R&D to satisfactorily addressed all technology gaps to enable the construction of a reliable prototype or the performance of an important proof of concept test. (I think that technically competent reactor designs fail at this stage due to a lack of funds to continue). The second is commercial; is the technology reliable, accepted by the regulator and cost competitive against its alternatives?

The operation of an SMR or a fleet of SMRs requires national soft and hard infrastructure such as:

  • Physical facilities for the delivery of electricity [or heat];
  • Site and supporting facilities for handling and disposing of radioactive waste;
  • Legal, regulatory and policy framework;
  • Financial resources necessary to implement the required activities;
  • Trained human resources.

In fact, the paper recognises 19 infrastructure issues (Table 2 of report). This is a useful list. Civil servants looking at government support for this technology should review this list to see if it identifies any expensive or difficult hurdles.

One of the issues with SMRs is the potential for them to be built rapidly – several a year – with the potential for deployment in countries other than those in which they were designed and built. These two factors present a challenge to site licencing which is much discussed.

For countries that already have a nuclear industry the hosting of a SMR or fleet of SMRs should not pose great legal, regulatory or infrastructure issues although the siting requirements may need further consideration as with potentially reduced emergency planning zones and less cooling water requirements these plants can go on a wider range of sites. It would also be necessary to consider the county’s ability to manage the fuel cycle and waste produced by the SMRs if they differ from the existing fleet. The paper gives an update on progress in several countries.

For countries without an existing nuclear industry the IAEA has outlined an approach in an earlier paper (Milestones in the Development of a National Infrastructure for Nuclear Power, IAEA Nuclear Energy Series No. NG‑G‑3.1 (Rev.1)). This involves stages before a knowledgeable commitment can be made to nuclear power; before they are ready to invite bids from suppliers and before they are ready to commission and operate the first power station. Each of these stages are discussed.

It is interesting to consider how this might apply to the Russian concept of floating power stations where the extreme view could be that the licensing, safety and fuel cycle issues are all managed by the Russian company to their national standards and the host country has an electric cable running into from offshore. How different is this to a French PWR providing power to the UK via a cable running under the English Channel?

Section 3 of the report is a review of the prospects for SMR technology which the IAEA rate as promising. Section 3.2.4 seems to suggest that public are certain to accept the technology because it is the only way to hit the IPCC’s decarbonisation target. I am not convinced!

Section 4 identifies stakeholders of which the keys ones are the designer/supplier, the owner/operating organisation, the technical support organisation, the investors, the regulatory bodies, the government and the public. It then discusses regulatory frameworks including the IAEA and OECD/NEA and WENRA and discusses goal setting and prescription as the two major licensing approaches before introducing the SMR Regulators’ Forum.

Section 5 concentrates on near term deployable SMR technology and provides a road map in three sections: owner or operating organisation, designer/vendor of the technology, regulatory bodies. This section is very disjointed and hard to read.

Section 6 looks at more innovative reactors designs which are further from market and highlights technical areas and R&D activities that are likely to absorb effort and funds on the pathway to deployment. This section also reviews six technologies that are being considered and takes a speculative look at the potential integration of renewable energy sources with nuclear sources.

An annex to the report reviews three designs of SMR in operation or under construction.

This could be a very interesting report but the drafting is poor making it hard to read from beginning to end. It does however give an impression of the breadth and depth of work that is required to support a nuclear power plant. I’m sure that it could be useful to a civil service providing government funding and support to the SMR industry. What would be useful is a map showing the development path for SMR and AMR reactors with a series of gates through which they have to pass, a discussion about what needs to be achieved before a reactor design can pass each gate and the technological and financial risks implied, who is responsible for the risks and an estimated cost and time for reaching each gate.

Streamlining the licensing of Small Modular Reactors, WNA Webinar


WNA webinar

I watched the World Nuclear Association webinar about streamlining the licensing of Small Modular Reactors on July 28th. This was an interesting event with some good speakers. It is currently available on-line here.

The grumble behind the event is that, while companies want to sell their reactors around the world the pesky regulators in each country they want to build in want their say on the suitability of the design and this is tiresome, time consuming, expensive and may lead to country-specific design changes. The speakers made a good case that their jobs would be easier and that SMRs could start generating energy sooner if the regulatory barriers were at least lowered. We were also told that this is important for decarbonising the world energy market which is a relatively new way the SMR companies are trying to lean on Governments.

The audience was challenged by Tom Bergman, Vice President of Regulatory Affairs, NuScale (a leading SMR design/build Company from the USA) with the question “Do you believe that a design approved in the USA is not fit for somewhere else?”. Maybe we could ask him if he would be happy for a British designed reactor, approved by the British regulators and built in Britain to be operated in his backyard without US inspection of the safety case, design, build and operation? We also heard from Sol Pedre, Manager of CAREM project, the National Atomic Energy Commission, Argentina (CAREM is a simplified PWR being built in Buenos Aires province) who, rather naively in my opinion, thought that if they could build and operate a reactor in Argentina then that should go a long way to convincing other regulators that the design is safe enough for worldwide deployment.

Nadezhda Salnikova, Head of Business Development Department of Afrikantov OKBM, JSC, ROSATOM (this is the company that designs and builds Russia’s nuclear propulsion projects such as submarines, icebreakers and floating nuclear power plant) commented that they produce plant for use within Russia under Russian regulatory supervision but the floating power stations can go anywhere. A lack of global licensing means extra work for the Company and work for the local regulators that may be beyond their capabilities.

It was suggested that new nuclear nations could simply accept the regulatory approval of the country selling the reactor. I suspect that this runs counter to IAEA expectations but might be acceptable if a floating plant was to be temporarily positioned following some crisis and operated by experienced staff. This is little different to a nuclear-powered submarine or ice breaker visiting a foreign port.

I have some sympathy for the potential loss of design stability caused by local requirements. This potentially makes the design chain and build more complex but we are talking about an industry that, according to the IAEA had more than 70 SMR designs running in 2020  (Ref. here) while NuScale have designed 50, 60 and 77 MWe versions of their reactor before building any. Design updates do not seem to be a particular problem. Meanwhile modern flexible manufacturing systems should enable slightly different builds to be accommodated on the production lines without reducing shareholder value too far.

The problem with attempts to produce global standards is that most countries agree with the concept providing that the world adopts their existing standards (hence my question to Tom Bergman above).

This event did not really explore the barriers to closer working of the regulators across the world and the advantages that might accrue from converging regulation. I would be interested to see a  comparison of the regulators. What do they do in a similar fashion? what do they do differently? How much scope do their national laws and guidance give them to meet in the middle? Why would they want to do this? How much of the licensing effort is based on design and how much on siting, building and operating? Knowing this, we might then be in a better position to move partial streamlining of international licensing from an aspiration to a realistic target. (This information may be available in the WNA report “Design Maturity and Regulatory Expectations for Small Modular Reactors” which I haven’t yet read in full).

Small Modular Reactors are often based on evolutions of proven technology with enhanced levels of safety built in. Much of the additional safety comes from the small size and layout of the plant greatly reducing vulnerable pipework and reducing dependency on active systems for layers of safety. They have reduced the number of systems (valves, pumps, filters, tanks, chemicals, switches etc) that need to be considered. It seems logical to assume that their safety cases are simpler and fewer systems means fewer things to understand and approve. Design approval should be quicker.

Importantly the construction takes place in factories, possibly in a foreign country. What expectations will the regulator have for quality control and will they require to inspect the reactor during build?

If governments wish to see SMRs contributing to low carbon electricity, district heating, process heating and hydrogen production in the not-too-distant future then they do need to encourage regulators to do their bit to hasten the process without compromising safety. Generic Design Assessment (GDA), which takes about 4 years and is not mandatory, is far from the only issue. They also need to consider how the licensing of sites and operators will be undertaken if the market penetration talked about comes to pass.

What will the siting requirements be? Currently the UK process spends a lot of time and effort considering if a particular site is suitable for a reactor. That may be acceptable if you are only going to build one or two sites a decade but we cannot expect, for example, a foundry to spend years of effort to get permission to use a small (or even micro) reactor to melt metal. What siting processes do we need if, for example, six reactors are going to built and deployed each year?

In the UK the ONR has recently announced new guidance for parties requesting Generic Design Assessment of SMRs and AMRs (Advanced Modular Reactors). It would have been interesting to hear a discussion of this guidance, and the strategy behind it, to see if it goes someway to meeting the aspirations of the reactor manufacturers.

The UK 10 point plan calls for demonstrator SMR and AMR deployment in the early 2030s. But what is the strategy to deploy them, including siting them, in the following years?

I started listening to this webinar thinking about the issue of using one design of reactor in several different countries but ended up thinking that a more difficult issue (in the UK) may be that of gaining public and regulator acceptance of many more nuclear reactors doing a wider range of jobs requiring them to leave their large, well-protected sites, in the countryside with their hundreds of well qualified workers and instead sit in one corner of an industrial site or in the outskirts of a town and with a much smaller staff. This is  a national, rather than an international, issue.

I’m grateful to the WNA for organising this webinar and for the speakers who gave their time. It is an interesting topic and was well presented. A good case was made that life for a reactor vendor would be easier if some of the regulatory barriers were streamlined. It was not made obvious that this was likely or even possible. The question in the webinar title was not answered.




Keeping the ICRP Recommendations Fit for Purpose

The science behind radiological protection is complex. It starts with the physical interaction between ionising radiations and the material that composes the human body (and other biota), then considers the potential changes induced by these interactions, including the response of different issues within the body and the whole body implications of those local responses, and tries to quantify the harm that might be done (detriment). It then considers the acceptability of this harm in terms of the tolerability of risks and by putting them into perspective with other risks.  It also considers how different groups and individuals might respond if exposed, recognising workers, the public and patients as different groups with different potential gains and losses and planned, existing and emergency exposure situations. The field thus encompasses physics, biology, sociology, ethics and politics.

The International Commission on Radiological Protection was “established to advance for the public benefit the science of radiological protection, in particular by providing recommendations and guidance on all aspects of protection against ionising radiation. The Main Commission is the governing body, setting policy and giving general direction” (Ref).  The recommendations of the ICRP form the basis of radiological protection around the globe. A useful review of the effects of this last major restatement of the recommendations can be found in a PHE paper “Application of the 2007 Recommendations of the ICRP to the UK”. (Ref)

ICRP have now pre-released a major discussion document as an early step in the consultation process for the next round of recommendations. Christopher Clement et al 2021 J. Radiol. Prot. in press. On line (updated version) available at This article is based on the accepted manuscript 20 July 2021.

In this we are reminded that the objective of the system of radiological protection described in ICRP-103 is “to contribute to an appropriate level of protection for people and the environment against the detrimental effects of radiation exposure without unduly limiting the desirable human actions that may be associated with such exposure”. The review that preceded this document started 20 years ago and took 10 years. “While it is safe to conclude that the System is robust and has performed well in relation to the protection objectives, the System must adapt to address changes in science and society to remain fit for purpose.

It is suggested that the ICRP-103 objective to prevent tissue reactions (deterministic effects to us oldies) should be modified to recognise that there are medial situations, emergency situations (and space exploration) where tissue reactions may be tolerated to achieve the desirable benefit of a particular activity. This seems sensible but is going to add, rather than remove, complexity.

A review of the lifetime risk estimates imbedded in the concept of detriment is due a review to reflect the evolution of scientific knowledge of risks and expert judgement. “In addition, explicit recognition of differences in detriment with age at exposure and between males and females could improve the clarity of application of the System, showing, in particular, that risks to young children are greater than risks to adults, and that risks to older individuals are low.” This could be useful, for example, in removing the perceived need to evacuate elderly people from their homes during a radiological or nuclear emergency to avert radiation doses of as little as 30 mSv which are of no real threat to them.

The discussion paper points out that the current system “principally deals with health effects resulting directly from exposure to radiation” which is not entirely in line with the WHO definition of health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”. Including mental and social wellbeing in the system can only make it much more complicated, situation dependent and subjective (but pretty much removes the need to worry about the physics of the fundamental interactions).

There is a section (Section 2.3) on the protection of the environment and non-human biota. I have always considered this a job creation scheme for radiobiologists and mathematical modellers (of which I used to be one) and of little practical value in the real world of radiation safety. I realise that this view sees me ejected from the moral high ground.

In Section 2.5 the paper reports that “There have been many requests for more guidance on how to balance societal, economic, and other factors in the optimisation of protection and safety, requiring input from many fields of expertise” and summarises the work that ICRP have published in this general area. This includes ICRP Task Group 114 which seems to suggest that there are occasions where the lowest exposures or risks are sought when a better balance could be achieved to advantage.

Also in this section is a discussion of a more holistic approach in safety assessments of medical facilities. Again, this seems to be running the risk of making the system more complex and maybe asking too much of one stream of work.

Section 2.6 discusses dose limitation and worries that, since it only applies to planned exposure situations, it fails the “ethical obligation to protect individual people under all circumstances”. This seems to me to be a bit like worrying that the seat belt and airbags in my car don’t provide me with any protection when I am walking around a shopping centre.

The report suggests a broader principle which would apply in all situations and encompass the concepts of limits, constraints and reference levels, possibly combining the latter two concepts into one. This is an interesting thought, worth thinking about provided the ICRP are willing to back peddle if it does not work out as hoped.

Dose constraint

A prospective and source-related restriction on the individual dose from a source, which provides a basic level of protection for the most highly exposed individuals from a source and serves as an upper bound on the dose in optimisation of protection for that source. For occupational exposures, the dose constraint is a value of individual dose used to limit the range of options considered in the process of optimisation. For public exposure, the dose constraint is an upper bound on the annual doses that members of the public should receive from the planned operation of any controlled source.

Reference level

In emergency or existing controllable exposure situations, this represents the level of dose or risk, above which it is judged to be inappropriate to plan to allow exposures to occur, and below which optimisation of protection should be implemented. The chosen value for a reference level will depend upon the prevailing circumstances of the exposure under consideration.


The report states that “defining a fundamental principle to protect the individual would result in a System where all three fundamental principles apply under all circumstances regardless of the exposure situation or category. This change would require the re-examination and clarification of the distinctions between limits, constraints, and reference levels”. (I’m not sure how you can put a useful dose limit on an accident or malicious use of radiation).

Section 2.7 suggests that the experience of using the three exposure situations introduced by ICRP-103 has led to the opportunity to update, clarify and expand the guidance. This seems reasonable and the application to space travel interesting.

ICRP identify ethics, communications and stakeholder involvement and education and training as important overarching considerations and briefing discuss each in turn in Section 3.

It is proposed to use absorbed dose (in gray) for the control of doses to individual organs and tissues for the avoidance or minimisation of tissue reactions leaving equivalent dose (in sievert) as an intermediate step in the calculation of effective dose. “Radiation weighting could then be considered separately for tissue reactions and stochastic effects for the calculation of radiation-weighted absorbed dose in Gy and effective dose in Sv, respectively.” This is intended to “apply scientific knowledge more appropriately and simplify radiological protection, with a clearer distinction between organ/tissue doses in absorbed dose in Gy and effective dose in Sv”. This does seem more transparent than the switch we currently make from seiverts to grey at (an arbitrary) high dose as at low dose you are concerned about stochastic effects and high doses with tissue reaction.

The paper reports discussions with ICRU with the intention that “the measured quantities for the estimation of effective dose would be related directly to effective dose in the reference phantoms, renamed as ‘dose quantities’ (ambient and personal dose) rather than ‘dose equivalent quantities’. Operational quantities for the measurement of doses to the skin and lens of the eye will become ‘absorbed dose quantities’”. Another episode where those of us who work around radiological protection are required to forget the hard learned jargon we work with and replace it with a different set.

In Section 4.2, discussing effective dose, the paper discusses the increased use of more accurate and differentiated anthropomorphic phantoms leading to more accurate and transparent values of detriment and relative detriment separately for males and females of different age groups. The report suggests that “Revisions to the methodology of calculation of effective dose could improve its suitability for the assessment of risk. Best estimates of health risk should be calculated using estimates of absorbed doses to organs/tissues and age- and sex-specific risk models for individual types of cancer, but risk estimates at low doses will still be subject to the uncertainties inherent in risk projection models”. The question this raise in my mind is “are the age and sex differences larger than the uncertainties in the estimates?”

It is suggested in Section 4.4 that the revision of dose per unit intake values in the light of the new recommendations should be more rapid than previous experiences due to preparatory work and experience gained. This seems to be a reasonable hope.

Section 5 suggests a review of the classification of radiation effects as either stochastic effects or harmful tissue reactions to ensure that it remains fir for purpose, suggesting that “For example, for protection purposes, it may be useful to distinguish between severe and other tissue reactions, or between short-term and long-term health effects”. This seems reasonable. There are occasions where the gain from a process may be worth suffering a mild or temporary tissue effect.

Since the last recommendation were made there has been considerable research and epidemiological study of the impacts of low exposures to ionising radiation. A Task Group is currently reviewing the linear no threshold assumption in the light of this work. It looks likely to survive.

It is almost certain that different people have different susceptibility to harm from ionising radiation but likely that there is insufficient information to include this in a system to protect workers and the public. “However, there are already efforts to individualise radiological protection of patients which should be considered in the review of the System, taking into account scientific, ethical, and practical aspects”.

Similarly, there is now more information on heritable effects that should be considered.

Likewise, there is more data on relative biological effectiveness and it is likely that a more sophisticated approach may now be appropriate.

The idea that “detriment could be calculated separately for males and females and at different ages at exposure, and the corresponding values of relative detriment could be used directly in the calculation of effective dose, rather than the current use of simplified age- and sex-averaged tissue weighting factors” sounds good. As does “explicit treatment of detriment from irradiation in utero could also be re-evaluated”.

There will also be a conversation about the replacing detriment with other proposed measures of harm such as fatality or disability-adjusted life years.

The discussion paper concludes that “The last review of the System of Radiological Protection was initiated 23 years ago, and the current General Recommendations (ICRP, 2007) were published 14 years ago. The System has performed well and remains robust, and there are significant practical benefits to stability in the System. Nonetheless, it must progress to remain fit for purpose as society evolves, scientific understanding advances, and new uses of ionising radiation emerge”.

The ICRP and others continue to research the effects of ionising radiation on people, biota and the environment. A time comes when the strengths and weaknesses of the current system should be discussed and new knowledge should be systematically reviewed incorporated into a revised international system of radiological protection. It appears that that time is approaching. This paper is one step in the consultation process. An ICRP Digital Workshop on 19 – 20th October is another step (Ref).

I shall watch this process develop with interest and get involved if I deem it good use of my time.