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

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.




IAEA EPR-Medical Physicists 2020 – Guidance for Medical Physicists Responding to a Nuclear or Radiological Emergency


In the event of a nuclear or radiological emergency hospital medical physicists may find themselves providing front-line response to the event or supporting their hospital’s efforts to triage and treat potentially contaminated casualties.

The objective of this IAEA publication is to guide the trained clinically qualified medical physicists (CQMP[1]) to act appropriately in a nuclear or radiological emergency and ensure that an efficient and coordinated contribution is made to the management of such an emergency. The knowledge of the CQMP can be vital in the preparedness and response to nuclear or radiological emergencies.

The report is accompanied by a pocket guide which summarises most of the concepts given in the full report and is designed as a working aid. But at 78 pages it would require an unusually large pocket. Rather than be an on-the-day aide-memoir the pocket guide covers a lot of preparedness information from the main report. EPR_Pocketbook_web.pdf (

The main report starts with an introduction to emergency planning giving various definitions of emergencies and then a quick overview of the roles the medical physicist might occupy in the local and nation emergency response plans. The noted roles are:

  • Radiological assessor (RA) requiring a qualified expert in radiation dosimetry;
  • Scientific and technical advisor giving advice on matters related to a nuclear or radiological emergency;
  • Trainer in radiation protection providing training within their own clinical environment and, possibly, within and beyond their hospital. During the emergency the trainer will be able to provide quick briefings on radiation protection to the emergency teams.

The medical physicist may serve in a pre-hospital function supporting triage teams and decontamination actions or in the hospital providing advice and training to medical staff.

I think I would have preferred the report to start with what a nuclear or radiological emergency might look like to hospital staff: many people turning, some injured, some contaminated (some both injured and contaminated), many worried well. This may better grab the reader’s attention.

The concept of a scalable incident command system, allowing multi-agency coordination and rapid decision making over a range of scale of event and the medical physicist’s position in the chain of command are discussed. The importance of each player knowing who they report to and to whom they are responsible in a crisis organisation and the understanding that this may not align with normal management is stressed. The diagram given here, cut and pasted from another document, is not helpful. Showing the medical physicist’s position in a chain built round them might have been better.

In section 4, the report runs through the preparedness phase tasks of risk assessment, training, criteria for exposure, potential roles and responsibilities, personal protection and radiation monitoring, procedures for donning protective clothes & monitoring. This section is not a model of clarity and covers material that a medical physicist might be expected to know.

Section 5, which covers activities related to the response, sees the medical physicist implementing the hospital emergency response plan and ensuring that the facility is protected. They will provide briefings on radiological protection and what may occur during the handling of contaminated patients and they will ensure that proper arrangements are followed to minimise the impact on the hospital resulting from the presence of contaminated patients. This section comes with a useful flow chart tracing the possible pathways to treatment for casualties with different combinations of needs, a list of equipment that might be useful and a list of possible actions (including a flow chart showing different actions assigned to different roles in a coordinated manner).

There is also a section labelled the radiological control of areas which is cut from another document and outlines the demarcation of areas for different purposes and the control of people moving through the system to minimise the spread of contamination. Maybe this material should be in the planning section.

Section 6 is entitled early dose magnitude estimation and decontamination. It suggests that accurate dose assessments are unnecessary in the response phase of an emergency; what is needed is a magnitude assessment: is there a problem with either external radiation or contamination that must managed along with the casualty’s clinical needs?

The report discusses how to assess external radiation dose and reviews the gamma ray constant and inverse square law which will probably not be new to many medical physicists. It also mentions a few computer tools such as the Rad Pro Calculator and the Radiation Emergency Medical Management (REMM) dose calculator which are useful to have available.

There are some tables showing how radiation dose can be deduced from observations about which symptoms show and how long after the exposure they show. Versions of these tables should be in the hospital’s emergency data set.

The report suggests that “Internal radiation doses can be extremely complicated to determine” and that “The aim of the assessment of internal contamination is to quantify the incorporation of radioactive material into the body and to estimate the committed effective dose and, where appropriate, the committed equivalent dose to demonstrate compliance with dose limits”. I think that this is appropriate for individual cases of internal contamination following operational mishap but is wrong in the context of responding to a nuclear or radiological emergency. Here the purpose would be to determine what, if any, medical care the casualty might require because of the exposure.

There is a short section on decontamination of casualties. I am sure I have read better.

In the section on the protection of the public (Section 6.2) the report mentions using plume models etc. to estimate deposition levels but gives no clue about how to manage the results. It also talks about determining isodose curves around sealed sources to help the determination of public external exposure.

The collection of excreta for radionuclide analysis is mentioned but no details of the assay methods or reference to dosimetry models used to estimate dose.

After the initial crisis stage there may be a requirement to improve dose estimates. Section 7, which discusses this area has some “key considerations” and some equations but little in the way of practical advice. Maybe following the references quoted may prove more helpful.

In Section 8 it is argued that Medical Physicists should “enhance their communications skills, so that they can contribute to the timely dissemination of relevant information and contribute, all with the response team, in managing individuals and professionals involved in nuclear or radiological emergencies”. You might have thought that these skills, as opposed to speaking to worried members of the public, came with their job.

The psychosocial aspects of nuclear or radiological emergencies gets a sub-section but this does little more than point to further references.

The rest of the section is a very brief overview of communications skills.

Section 9 is a more helpful section on the contents of a “grab and go” bag. This includes dosimeters (EPD and badges), survey instruments, protective equipment, data sheets and forms and miscellaneous tools.

Section 10 gives a very detailed suggested syllabus for training medical physicists and reading lists which are predominantly IAEA publications and would need a fairly large bookshelf to hold and some considerable time to read.

Appendices provide more detailed advice on reception area layout, tags and forms and summary of OILs and reactions to their exceedance.

This is a potentially useful document for hospitals when considering their plans to cope with a nuclear or radiological emergency and considering how to use their radiation specialists. However, it is not only very uneven in the level of detail given but also does not seem to have considered what skills and knowledge the radiation specialist already has and where they might need some training.

It could be better.

[1] See IAEA Human Health Series No. 25, “Roles and Responsibilities, and Education and Training Requirements for Clinically Qualified Medical Physicists”

Book: Nuclear Emergency Planning and Response by Keith Pearce

Book coverI have just published a revised and much expanded version of my nuclear emergency response book. It now covers the wider UK nuclear industry with some comparisons to approaches in other countries. It looks at risk assessment, plan scoping, concept of operations, radiation protection, dose limits, the planning community, response and recovery. It mentions REPPIR-19 a few times.

This was a lockdown project, started when I found that my workload had significantly dwindled. It was not written with any group in mind but may be of interest to planners, responders and regulators in industry, local authorities and the emergency services.

It is printed in black and white which allows the cost to be kept down to £12 of which £3 goes to me as the author. I shall be donating my share to the Prince’s Trust since I believe that while lockdown has done me little damage, we need to give some extra help to those transitioning from education to work in these unusual times and the Trust will be far better at that than me.

I would be grateful for feedback if anybody does read it. Being “print on demand” It is quite easy to squash typos if they are pointed out and more chunky revisions are not too much of a problem.

Find it on Amazon at


IAEA Handbook on the Design of Physical Protection Systems for Nuclear Material and Nuclear Facilities

IAEA NSS 40TA new IAEA publication has been published (May 2021) (link here) . This has the objective to provide comprehensive, detailed guidance for States, competent authorities and operators to assist them in implementing the recommendations from the IAEA on the Physical Protection of Nuclear Material and Nuclear Facilities. This area is subject to the Convention on the Physical Protection of Nuclear Material (link here). The UK signed on to this, with some reservations as a member of the EU. I cannot establish the current position.

A Physical Protection System (PPS) is an integrated system of detection, delay and response measures. It should comprise people, procedures and equipment to provide defence in depth, with a graded approach, to address the range of threats identified in the applicable threat statement and to protect against both unauthorized removal and sabotage. The PPS comprises interior and exterior intrusion detection sensors, cameras, delay measures, access controls devices and response measures.

The handbook recommends a systematic design and evaluation of the PPS with requirements identification, design, and evaluation phases. These stages are each explained in some detail. This process is fine if you are starting afresh on a new site but, with an old site, you are more likely to be trying to combine systems with a range of ages and technologies into a workable and justifiable system. The principles need to be modified a bit for this circumstance.

The handbook advises on how to deter an attack on a site by making potential adversaries think it an unattractive target because of low probability of success or high risks to themselves.

There are detailed sections on physical protection systems (design, evaluation, testing and technology options) and the management systems required to keep it all operating effectively.

This handbook would be a good read for any security manager and security systems designer.

Dirty bombs and malicious source placement

There are a couple of reports of interest to local authority nuclear emergency planners in a recent Journal of Radiological Protection (Volume 40, Number 4, December 2020). These are part of the European Commission’s CATO mission which “proposes to develop a comprehensive Open Toolbox for dealing with CBRN crises due to terrorist attacks using non-conventional weapons or on facilities with CBRN material” (

The first comes from the Belgium Nuclear Research Center with Carlos Rojas-Palma as the lead author (Carlos Rojas-Palma et al 2020 J. Radiol. Prot. 40 1205). This reports on a series of experiments in which mocked up Dirty Bombs of a variety of designs were detonated in urban-like environments. These used a number of tracers to represent the radioactive elements and a variety of detection and measure techniques to record the dispersion.

The report is constrained by security concerns so is unfortunately a bit coy about some of the important details.

Following a ground level explosion activity was found up to 5 m high on nearby walls and that the activity on the ground at 30 m was about 5 % of that at 9 m. They concluded that most of the dispersion was ballistic rather than turbulent. Whereas that might be true in this case, or even in most cases, it might not always be true; it could be assumed to depend on the physical form of the radioactive source and its packing and the force, temperature and geometry of the explosion.

The authors state that, in this instance, the radiological red zone would extend beyond a 50 m perimeter but, without any idea of the effective source strength and the blast being published the value of this observation is greatly reduced.

The paper suggests that any aid or movement of severely injured victims would ideally be performed by personnel in full protective equipment.

Airborne radiation levels can remain elevated for tens of minutes. This is affected by the weather conditions and the layout of buildings. Respiratory protection should be considered for anyone working in the red zone.

The levels of deposition on dummies placed in the vicinity of the blast suggest that decontamination will be needed for people within 50 m of the blast and monitoring, prior to release or decontamination, for those further out.

Deposition on walls was significantly lower than that on the ground but it is suggested that a thorough decontamination of the surrounding area would be needed to satisfy public demand.

For a device detonated in a car the distribution of ground deposition was rather random, making surveying and reporting harder and more time consuming. It was suggested that the fraction of radioactivity remaining in the vehicle would pose difficulties for forensic investigations.

This is a limited report of a series of careful experiments. It is to be hoped that the full results are available to, and explained to, the relevant emergency planners and first responders.

The second report, also with Carlos Rojas-Palma as the lead author (Carlos Rojas-Palma et al 2020 J. Radiol. Prot. 40 1286), discusses retrospective dosimetry to assist in the radiological triage of mass casualties exposed to ionising radiation. It suggests that the outcome of a terrorist event could be mass casualties with radiation exposure of individuals ranging from very low to life threatening and in numbers that surpass the capability of any single laboratory. Thus, it argues, an international network of laboratories would be needed. The European RENEB network is such a network (according to their website at PHE is a member). A paper outlining their objectives is available at

This report discusses a series of exposure experiments with a 0.65 TBq and a 1.5 TBq Ir-192 sources, a bus and a collection of water-filled canisters and anthropomorphic phantoms. Detectors included a range of TLDs (Thermoluminescent dosimeter), OSLs (Optically Stimulated Luminescence) and body-temperature blood samples.

The project achieved three things: measurements of the doses that could be accrued by people sitting on a bus near an unshielded radioactive source, an inter-comparison of the reading of dosimeters by different laboratories and the evaluation of newly developed retrospective dosimetry methods. “Retrospective dosimetry” allows the doses of accidently exposed people to be measured after the event and can be used to inform the medical care they receive.

IAEA Nuclear Security Series No. 41‑T

Technical Guidance Preparation, Conduct and Evaluation of Exercises for Detection of and Response to Acts Involving Nuclear and Other Radioactive Material out of Regulatory Control

The IAEA’s Nuclear Security Series provides international consensus guidance on all aspects of nuclear security to support States as they work to fulfil their responsibility for nuclear security. The IAEA states that “The overall objective of a State’s nuclear security regime is to protect persons, property, society, and the environment from the harmful consequences of a nuclear security event. With the aim of achieving this objective, States should establish, implement, maintain and sustain an effective and appropriate nuclear security regime to prevent, detect and respond to such events. The nuclear security regime covers nuclear material and other radioactive material, whether it is under or out of regulatory control, and associated facilities and associated activities throughout their lifetimes.

The steps on the way to achieving this include the development of a national detection strategy, the development of detection systems and the processes to monitor and act upon alarms. The response to a genuine event includes notification and confirmation/assessment, location and categorisation, recovery of sources and collection and preservation of evidence. These are explained in detail in IAEA Nuclear Security Series No. 15.

There is an expectation stated in paragraph 6.21 that “The State should carry out exercises under the plan using credible scenarios. Competent authorities should perform exercises and drills at regular intervals, in order to evaluate the effectiveness of the plan. When possible, States should consider participating in regional and international exercises and drills.” IAEA Nuclear Security Series No. 41‑T gives a comprehensive account of how these could be managed.

Exercises can be based on a structured and moderated discussion (a table top exercise) or on activities performed in an operational or field situation to enact a realistic scenario in a manner that simulates, to some extent, the stress and practical constraints of an actual incident (a drill or field training exercise).

The steps taken to plan an exercise include:

  • Determination of the key activities to be exercised – the scope and objectives of the exercise;
  • The format and type of exercise, identifying the constraints that these impose;
  • Agreeing a planning timeline with the key stakeholders;
  • Developing and approving an exercise scenario;
  • Identifying the exercise participants and their roles and determining how any gaps where organisations are not playing will be filled;
  • Developing evaluation criteria.

The report goes through these steps in more detail giving useful advice and warnings as it does. It defines the roles of Exercise Director and exercise planning team; controllers and facilitators, evaluators and players and the support from media spokesperson, observers, safety officer, qualified expert in radiation protection and the rapporteur.

Section 4 of the report discusses: setting up the exercise and preparing for exercise safety; providing exercise briefings; conducting exercise play; and holding debriefing activities and section 5 evaluation.

Appendix 1 gives a useful list of example key activities and actions while Annexes give templates for exercise planning, exercise documentation, assessment and feedback forms and exercise reports as well as an example exercise scenario.

This report is a useful read and contains useful resources for anyone planning such an exercise.

The physics of the Chernobyl accident

My latest book, an attempt to explain the Chernobyl accident to people who know a bit about physics but not a lot, placing it between the many accounts that have concentrated on the human story and some very technical reports, is now available on amazon after a professional work over by Art Works who have greatly improved the layout and type setting.

Find it at


Handbook for Regulatory Inspectors of Nuclear Power Plants

Techdoc 1867

Regulatory inspections of nuclear facilities and activities generally consist of a predefined programme of planned inspections and reactive inspections which are both announced and unannounced to ensure that the inspectors obtain a clear understanding of the overall operation of the Nuclear Power Plant. The purpose is to provide independent assurance that the operator is in compliance with regulatory and license requirements and conditions.


This Techdoc is a rather strange accumulation of advice on the inspection process.

GSG-13 identifies four basic methods for obtaining information during an inspection: Monitoring and Direct Observation; Discussions and Interviews; Document Evaluation; and Independent Tests and Measurements. These are expanded on in Section 2.3.2 listing suitable things to inspect in each style and giving hints about how to make the inspection more successful.

Inspections generally should follow a plan – perform – evaluate – report process, which is expanded upon in Section 3, which looks at the phases, and further in Section 4, which looks at how inspections are undertaken. This includes recommending that an inspector be armed with: note book, clipboard, drawings/diagrams; voice recorder; portable computers, tablets; laser pointer; camera; radiation meters; pyrometer/thermal imaging device; and Inspection mirror, providing the site rules allow them.

Section 4.3.1 is an extraordinarily detailed section about some of the components of a nuclear plant (gauges, valves, motors, pumps, pipe supports etc. which seems to be more general plant familiarisation than inspection material. Some nice diagrams are included.

A potentially useful annex gives tables of questions to ask during and after a tour of the plant.

This Techdoc makes an interesting read and could be useful to a reasonably novice inspector as a self-teaching aid and to a more experienced one as a refresher. However, I cannot help thinking that mature national regulators will already have their own material that fits this purpose. For example in the UK the ONR has its extensive set of technical assessment guides (TAGs).