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

IAEA EPR-MED

https://www.iaea.org/publications/13483/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 (iaea.org)

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”

FEMA – Key Planning Factors and Considerations

What would you do?FEMA report

…if a dozen dead birds are found near a truck accident site?

…if 20 people complain of tingling in the mouth after eating at a fast-food restaurant?

FEMA have some answers. They have published a new 324-page document discussing key planning factors and considerations for response to and recovery from a chemical incident August 2021).

https://www.fema.gov/sites/default/files/documents/fema_chemical-kpf_060321.pdf

The report shows the potential complexity of responding to a chemical event. Unlike radiological events, chemical events could result in overwhelming numbers of acute casualties, some of which require urgent medical attention with the correct treatments and anti-toxins for the chemical involved – which may not be identified at the start of the event. First responders may be in immediate danger from the contamination themselves, something that is not likely to be true to the same extent for radiological emergencies.

There are broad similarities between the response to a chemical event and to a radiological event (a dangerous substance that can move with air and/or water movements, the need to make decisions with weak information, a complex issue to explain to the public while needing them to urgently take heed of advice, a potentially complex recovery process) but also important differences (rapid onset of medical crisis, wider range of substances to understand).

The FEMA report provides brief details of several chemical accidents, showing the range of events that are included in this class and the complexity of response. It also identifies and discusses the characteristics that are common to chemical accidents which includes the fact that their on-set can be rapid, a quick and effective response is required to save lives, first responders can become exposed, decisions need to be made quickly with a limited understanding of what has occurred, large areas can be affected, communications with the public and between responders is important, medical facilities can be overwhelmed and recovery may take a long time.

It then lists seven Key Planning Factors (KPF), each of which is then given a chapter:

    1.   “Prime the Pump” Pre-Event Planning;
    2.   Recognize and characterise the Incident;
    3.   Communicate with External Partners and the Public;
    4.   Control the Spread of Contamination;
    5.   Augment Provision of Mass Care and Human Services to Affected   Population;
    6.   Augment Provision of Health and Medical Services to Affected   Population;
    7.   Augment Essential Services to Achieve Recovery Outcomes.

It justifies pre-planning with the observation that “A large-scale chemical incident with mass casualties is a realistic threat facing both urban and rural communities nationwide. The risk of misuse or accidents involving toxic industrial chemicals (TIC), which are widely stored in large quantities and are routinely transported by rail, waterway, highway, and pipeline, is substantial”. They also believe that a terror attack using chemicals is credible.

Multiagency planning and preparation are required to face this threat and enable a prompt and effective response. A “whole community” concept of operations is suggested.

The report suggests a systematic approach to planning and preparedness with several discrete steps recommended, each of which is explained in detail with lists of suggested consultees, reference documents, check lists and resource requirements.

It stresses the importance of agreeing how decisions will be made suggesting a process whereby stakeholders agree which decisions will need to be made, the minimum information needed to make them and the potential sources for that information. Decision making processes should be established to select among available options for evacuation, shelter-in-place, decontamination and waste management balancing political/social priorities and public health protection against time and cost constraints, and, therefore, should include discussion of reimbursement/ compensation for resources provided and contingencies if resources are damaged, destroyed, etc.

Another important area for discussion is medical resources. The planning process should establish protocols and procedures for the prioritization of medical resources.

There are a range of ways in which a chemical event can become known – this varies from automatic alarms on chemical plant, reports of smells or gas clouds, reports of unexplained illnesses or collapses of people or animals, active monitoring of public spaces and food. The quicker these signs can be picked up the better. The report discusses possible indicators, what they might mean and how best to use them. By considering what signs might be available and what they might mean in advance the planners increase the likelihood that an event can be detected earlier allowing a better response.

The next step is to characterise the release and its extent with the safety of first responders as a high priority. This requires equipment, training and coordination.

There is a nice discussion about atmospheric dispersion and modelling.

The third KPF refers to communication with external partners and the public. It stresses the importance of communication to enable a coordinated response across multiple agencies, jurisdictions and levels of authority and to inform the public providing key information and advice on self-preservation while countering misinformation and misperceptions.

The section discusses how communications can support a coordinated response, how to inform the public, how to provide time-critical messaging, strategies for effective communications, and best practice (the latter being a useful checklist of 13 elements).

Controlling the spread of contamination (KPF 4) may save lives and will protect the environment. Depending on the nature of the incident, controlling the spread of contamination may involve environmental containment and/or remediation efforts; decontamination of people, goods, or property; and interventions such as evacuations and food recalls. A lot of important decisions may be needed, and considerable expertise and resource bought to bear.

The support of the affected population (Augment provision of mass care and human services to affected population) (KPF-5) provides life-sustaining and human services to disaster- affected populations, including feeding operations, emergency first aid, distribution of emergency items, and family reunification. Additional resources and services may need to be mobilized to support individuals with disabilities, limited mobility, limited English proficiency, children, household pets, and service and assistance animals. Mass evacuations result in a varied group requiring a range of support services.

The basic objective for Emergency Mass Care is to provide for basic survival needs including food, water, emergency supplies, and a safe, sanitary, and secure environment but hopefully it would go beyond that and cater for other needs, reducing the potential for psychological harm.

The report discusses the support that sheltered and evacuated populations might have and the multi-agency strategies that might be considered to prepare to meet these needs, the facilities that may be required to manage evacuations, provide respite, assistance and shelter.

KPF 6 is concerned with augmenting the provision of health and medical services to the affected population. A chemical event could result in a rapid build-up of casualties requiring specialist assistance, including determination of the active agent, the appropriate medical care and the steps required to protect the responders and medical facilities from contamination.

The report discusses medical treatment for chemical casualties which may require that the symptoms presented are treated while the active agent is unknown i.e. provision of oxygen to those exposed to a lung irritant.

The report mentions “CHEMPACKS” which are containers of nerve agent antidotes placed in safe locations around the country (the USA). I do not know if this system is replicated in the UK. The report recognises limitations to this system.

The Tokyo nerve agent attack in March 1995 was serious – 12 people died, 54 were severely injured, and around 980 were mildly to moderately affected. However, most of the 5000-seeking help, many of them with psychogenic symptoms, were understandably worried that they might have been exposed. This demonstrates the value of rapid information dissemination via the media in reassuring the public. It also shows the importance of effective triage at receiving centres in ensuring that medical resources are reserved for those who really have been exposed.

The final KPF is “augment essential services to achieve recovery outcomes”. This section suggests that recovery begins during the planning and response phases. It divides the recovery into three overlapping stages: short term (days), intermediate (weeks – months) and long term (months – years).

Activities and resources needed to attain recovery outcomes will vary depending on the scenario, context, and location of the chemical incident as well as the incident’s impacts on the local infrastructure, economy, and workforce.

The overall objectives of recovery plans and prioritizations are to restore critical services as quickly as possible to limit cascading effects, and to return the affected community to a sense of normality.

After discussing each of the KPFs the report discusses federal preparedness, response and recovery, outlining the four escalating tiers of federal response. These are (1) an on-scene coordinator assessing the situation and watching the response (2) escalation to invoke the National Oil and Hazardous Substances Pollution Contingency Plan (3) a request to the Department of Homeland Security for coordination capabilities and additional federal agency support (4) a Presidential Disaster Declaration under the Stafford Act. These are discussed in turn with examples.

The report provides links to a wide range of additional information and both planning and response tools. Appendices provide a wealth of information including an overview of nine common toxidromes (syndromes caused by exposure to dangerous levels of toxins), a review of US chemical incident policy, legislation and regulation and chemical planning and notification requirements for responsible parties, environmental containment and remediation options, a flow chart showing how medical attention can be targeted and coordinated.

This is a detailed document covering a wide range of material. For a person with responsibility for planning for, or responding to, a chemical incident in the US it is probably a must read. For people with similar responsibilities elsewhere it is a recommended read – read it and compare your level of readiness with that described.

 

 

 

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 https://amzn.to/353MpQ0

 

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.

Improved public messaging for evacuation and shelter in place.

FEMA have just published on the internet a very interesting paper entitled “Improving Public Messaging for Evacuation and Shelter‐in‐Place Findings and Recommendations for Emergency Managers from Peer-Reviewed Research” (April 2021) (link here). It reports the findings of a comprehensive literature review on the factors that affect the level of compliance with advice on personal protective actions (Shelter in place and Evacuation) in the event of a storm, flood or wild-fire. While these situations are not entirely analogous to radiation emergencies and there may be differences in the behaviour of UK and US populations when faced with an external event, there may be some important messages for UK planners to be gleaned from this work.

The work is related to the Protective Action Decision Model proposed in the literature (see figure) which attempts to identify the cues people may be sensitive to, the level and nature of prior consideration, and the on-the-day perception of the threat, possible responses and how others are responding which may influence decision making.

The key advice to those planning systems to warn and inform the public is to understand the potential impediments to action and take steps to address these barriers in advance, provide consistent advice through multiple trusted channels and to provide frequent updates.

Among many observations, those that seemed most relevant to the UK nuclear industry include:

  • Individuals find environmental cues such as sights, sounds or smells that indicate an impending threat an aid to decision making. This puts the nuclear industry at a disadvantage because we cannot show pictures of storm clouds, fast flowing rivers about to burst their banks or raging forest fires. On the other hand, we have the dread many people feel about radiation helping to focus minds.
  • It was noted that, in response to a wildfire, individuals could be categorised into three broad groups:
      • Wait and see (the largest group);
      • Stay and defend;
      • Likely to evacuate.
  • Seeing neighbours evacuate or other leave was a predictor of increased evacuation across a number of hazard types. This is a well-documented response to an alarm and most people will have observed it where they have been in a building when the fire alarm is tested; many people look to others and copy their behaviour.
  • Receiving messages from family and friends in addition to the local authority influenced decision making. Many people will seek confirmation of the preferred path of action from their social circles before acting.
  • Local governments and businesses provide important social cues that can impact on risk perception. Advice to evacuate an area, or even to shelter in place, could be undermined if council employees continued activities such as cutting grass and collecting waste in those areas.
  • Receiving several consistent warning messages from multiple, credible and trusted sources increases the rates of compliance.
  • People tend to use social media as a complementary rather than their primary source of information. Social media was also often used to amplify or share information with others.
  • As mobile phone ownership is now more prevalent than home landlines, public alert and warning calls to landline phone numbers are becoming less effective. The increased reliance on mobile phones may also result in bandwidth congestion during an incident. In the UK where fraction of homes and offices with land lines is falling while the procession of mobile phones is increasing. (See Table A45 in ONS report here which implies that 82% of households have land lines and 90% have mobile phones).
  • Households with multiple vehicles evacuated in multiple vehicles often with staggered leaving times. This is in the context of an impending storm but is plausible in a radiation accident if only as a mechanism for protecting their vehicles. This would add to traffic congestion.
  • There is strong agreement across studies and hazards that women are more likely to take appropriate protective action (SIP or evacuate) than men.
  • Parents with children in the household tended to have more difficulties with making the decision to stay or to leave for hurricanes and flooding. While some of their concerns may be similar to those of other households (e.g., traffic congestion, fuel availability, uncertainty regarding destination, cost), children in the household, especially younger children and larger numbers of children, raised the anxiety level and increased logistical challenges, which caused delays in decision making. Again the dread of nuclear may balance these concerns.
  • Having a pet, especially where there is a strong attachment to the pet, decreased the likelihood of evacuation. Many studies highlighted concerns about shelters accepting pets, the added cost of evacuating with pets and the logistics of having a pet at a shelter as impediments to evacuation.
  • Adults who have dementia or other cognitive disabilities and a caregiver(s) who would evacuate with them have evacuation rates that are the same as, or lower than, others. Caregivers were concerned with the potential for those in their care to be exposed to stigma and lack of privacy in a shelter. They were also concerned that unfamiliar settings would exacerbate their symptoms. Family and friends (the social network) tended to play an important role in determining whether to evacuate or not.
  • Adults with dementia and their caregivers who did go to shelters experienced a range of difficulties, including increased agitation, emotional distress and disorientation. It was challenging for caregivers to provide normal levels of care and comfort in this environment.
  • Care facilities and their caregivers were challenged in making the decision whether to evacuate or not, given their sense of responsibility to their residents. This research also indicated the importance of care facility residents and their families deciding (and documenting) who would care for them in a disaster (e.g., whether or not they would evacuate to a family’s residence) and then not changing that decision as the threat neared.
  • Having a household plan increased the likelihood of taking the appropriate Shelter in Place protective action for a tornado. This may be presumed to apply for any threat, underlining the importance of prior information that encourages preparation.
  • Studies found that individuals grapple with many concerns when deciding to evacuate. According to these studies, the following concerns delayed or negatively influenced the decision:
      • Traffic congestion and the availability of fuel;
      • The ability and cost of evacuating with pets;
      • Costs of evacuation, including travel costs;
      • Potential issues around the legal status of undocumented immigrants;
      • Individuals faced with a public shelter as their primary destination had more reluctance to evacuate. Their concerns include crowding with strangers and being located farther away from social networks.

On the basis of the observations a number of recommendations were made:

  • Use websites and social media platforms and work with local media to provide authoritative, time-stamped, geo-tagged photos and videos of hazards such as rising waters and wildfires. Encourage individuals to share those visuals with friends and family, including via social media. Again, there are differences between these events and radiation emergencies to take into account but there is something to take away from this recommendation.
  • Warning messages should be clear, consistent and strong but not overly dramatic. Mandatory evacuation orders had more weight than voluntary ones and also carried increased media coverage.
  • Changing the geographic areas subject to advice can cause confusion and a resulting drop in compliance. This should be minimised where practical.
  • Messages that clearly described the probable personal impact of the hazard helped individuals realise that they would be personally impacted which motivated protection action.
  • Visuals such as maps and photos improve message comprehension and support decision making.
  • Authority figures acting as role models and being seen to comply is helpful.
  • Tourists who sought information from tourist offices rather than hotel staff were more likely to evacuate (this was in the context of a major storm brewing).
  • The current event should be compared to those that have posed similar threats. Hopefully nuclear industry will ever have a good back catalogue.
  • In the preparation stage relationships should be built with television and radio forecasters and other journalists likely to cover the story should it arise.
  • People should be encouraged to sign up to relevant alert and news feeds, including during the event.
  • There should be a mechanism in place to follow and monitor the social media of authoritative sources to keep information consistent and address inconsistencies and inaccuracies if they occur. In the UK we also try to coordinate the media lines taken before media releases are issued.
  • Communications strategies should be tailored to gender differences. For example, given that women are more likely than men to take protective actions, messaging on preparedness should consider the use of outreach channels geared toward women.
  • Include individuals with disabilities, access and functional needs, and associated advocacy organizations in developing and reviewing community plans for evacuation.
  • If an evacuation may be called for then consider breaking the news at a time that allows the travel to be completed during daylight hours.
  • When issuing evacuation orders, explain the risks that led to the decision to evacuate some zones and why other zones are not evacuating.
  • Provide information about public shelters, including items associated with comfort (e.g., availability of power, air conditioning, rest rooms, and space for families and pets) as well as services for individuals with disabilities and access and functional needs.

The slide library available here is a very good way to assimilate the information given in this report.

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” (https://cordis.europa.eu/project/id/261693).

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 http://www.reneb.net/ PHE is a member). A paper outlining their objectives is available at http://dx.doi.org/10.1080/09553002.2016.1227107.

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.

NEI Small and Advanced Reactors: Virtual Event 18/2/21

This was an on-line event organised by Nuclear Engineering International bringing together a collection of speakers to provide updates on the development of, and potential for, small and advanced reactors.

The website opened with a picture of a conference centre with signs to various “places” which you could enter with a click. Entering the auditorium showed a timetable for the conference and allowed the user to listen to the current talk. After the event all presentations were available to listen to again. The Exhibition Hall allowed you to read or download publicity material and watch promo videos from a number of developers of SMRs. The Networking Lounge allowed you to read and join a number of text threads with representatives of the Companies involved.

This was a brave, and very welcome attempt, to recreate the functionality of a conference. It couldn’t provide the impromptu chats in the queue for a cup of tea, which are a vital part of conferences in the real world, nor recreate the sensation of sitting in an uncomfortable chair wishing the tea break was nearer while trying to concentrate on a talk. I admit to doing other things, such as catching up on shredding old documents, while listening to talks.

We live in an interesting time where there are limited funds for investment, a growing need for energy, a growing urgency to be more careful with the planet we call home and a lack of consensus on the way forward. Candidate solutions for the future include greater energy efficiency, reduced per-capita consumption, renewable energy solutions with solar and wind being the main growth areas, and more nuclear power. Within nuclear power there is competition between ever larger and more complex reactor systems, large but “simplified” reactors, and smaller reactor systems.

This conference was about the small reactors, seen by many as the solution to the “too big” problem with full sized reactor systems. One stated advantage are that smaller cores make less demand on the engineering of large pressure vessels and containment buildings. The control and safety systems can be bought closer, even into the pressure vessel, and a greater reliance can be put on passive accident management systems. But the unique selling point is the contention that these reactors can be produced, either as a number of modules or complete, in factories, shipped to site by road, plugged in and they are off. This considerably reduces the construction risks and build time resulting in a quicker achievement of a positive cash flow. The reactors are less powerful but it is easy to line up multiple reactors to give higher outputs while the smaller output makes them suitable in areas that cannot be served by 1000+ MW units.

It was explained that the UK SMR reuses existing design and technology but the innovation is chiefly working out how to factory build it. The system is “low cost, deliverable and investable” with 80% of UK content. The next step, which starts this year, is GDA. This is important for the UK context but is also a badge of honour around the world. The ambitious plan for acceleration includes parallel identification and development of the site and the placing orders before the GDA is complete. It is suggested that they might fit well on NDA sites which have a nuclear history but are not big enough for gigawatt plant such as Trawsfynydd. After the first of kind a factory might be expected to produce two systems a year. If orders were to be higher then further factories could be built. In this manner the 5th unit should be 20 – 30% cheaper than first, down to about £50 kW.

Funding is in place for the GDA phase but not beyond. The company is lobbying for the UK policy situation to develop and sites to be identified. The company is confident that once production is underway then debt and equity vehicles will be sufficient to move them forward but government bridging funds may be needed to get there.

This was an upbeat talk but the reality is that they are playing in a crowded field and the UK has a poor record of being able to deliver fleet savings in nuclear build (except maybe in the nuclear submarine world where the figures are less well publicised) and has, for years, lacked a suitably forward looking and coherent energy policy. They are also competing with Russians and Canadians with a more obvious local market and a clearer path to that market and the Chinese with their very large investments in a range of nuclear technology. Too much depends on the UK government.

The IAEA has set up an International Technical Working Group on Small and Medium-Sized or Modular Reactors (SMR) with a number of sub-groups enabling international collaboration in the development of SMR and their applications. They have produced a booklet reviewing 72 designs, developed technology roadmaps for SMR deployment, generic user’s requirements and criteria and a tool for the economic appraisal. Interestingly (for me anyway) they have a project running looking at the emergency planning requirements for SMRs due to report in December of this year. (See IAEA material at https://www.iaea.org/topics/small-modular-reactors). The fact that there are 72 designs on offer shows up a problem. It is relatively cheap and sexy to design a reactor system and many organisations do this hoping to get a slice of future markets. Most fall out of the race and represent a waste of effort.

Rosatom claim to have “SMR solutions in Russia and for the global market”. They are developing and building small reactors for icebreakers, for floating power plant and for land based systems. Floating power plant are expected to be used in the North, replacing diesel, coal and old nuclear generators and providing heat and electricity. Because they are built in a shipyard they need very little local building and are floated away at end of life rather than decommissioned in-situ. They can also be repositioned mid-life if required. Their newer reactor designs are more compact.

By using these reactors in icebreakers (4 vessels each with 2 reactors) they have already achieved significant fleet savings (that pun was not intended). They also have identified markets, home and foreign, for the floating and land-based variants.

It appears that Russia has a very credible SMR programme with proven designs and proven markets.

We were told about “The Progress of HTR-PM in China”. This is a high temperature gas cooled reactor with ceramic coated fuel (TRISO particles, pebble bed format) and helium coolant. The programme has a long history including the reactors HTR-10 & HTR-PM and extensive engineering laboratory work. Almost all of the components are built in China. Unusually they have two reactors in parallel providing steam to a single turbine. Each reactor can provide 250 MW.th and 210 MW.e with cores 3m diameter x 11m high. Inlet 250 oC out 750 oC producing superheated steam. HTR-PM is currently in hot-testing with first criticality expected this year.

They now have proven technology and have plans to move forward. HTR-PM600 (650MW) will have six reactors feeding one turbine.  These will be used for co-generation and to repower coal power stations. An aspiration is to go to higher temperatures for hydrogen production.

Some ideas on financing SMRs and Advanced Reactors were presented. The poor track record of on-time completion, very high capital requirements and long times before return have given the industry a bad name and mean that nuclear is often a “bet-the-company” investment. Contract for difference and Regulated Asset Base are two attempts to manage the high cost of money in big build public interest projects.

It was suggested that SMRs significantly reduce all of the finance and risk problems of big-nuclear. They should be able to complete on programme, capital demands are lower, lead times are shorter, costs of delays are less and costs are such that they are not bet-the-company investments. Therefore they can be treated as conventional assets.

SMRs are like aircraft in many respects. Both are built in factories, safety critical, and highly regulated and are deployed as a fleet.  Interestingly it was claimed that an SMR requires a similar investment as an Airbus A-380 [I tried to verify this and found getting the numbers quite difficult but seems to be in the right ball park. The clearest cost estimate I found was a 12 unit NuScale (924 MWe) estimated to cost $2,850 per kWe giving costs of $2,633 Million (NuScale brochure) compared to $428 Million for an Airbus A380 (one unit not 12) https://247wallst.com/aerospace-defense/2015/12/26/how-much-does-an-airbus-a380-cost/ ).  As for large aircraft it is conceivable that SMRs could be sold on a Sale and Leaseback in which the lessee pays purchase price in instalments over a set period of time before becoming owners. The payments are treated as expenses rather than capital investment and the utility doesn’t have the liability for the plant on its books. An alternative is an operating lease in which the Lessor pays only rent and not pay-down of the capital costs, making it more affordable and viable in areas that could not afford nuclear power under current arrangements. It is hard to see a factory owner or a community buying one of these for cash to provide their energy needs over the next 20 years but they might lease one if it gives them reliable low-cost energy. It is noted that if the SMR is mobile (for example floating) it can be moved mid-life and follow the money.

There were a series of shorter presentations within chaired panel discussions. These provided a number of viewpoints.

Micro-reactors (up to about 10 MWe) are in various stages of development and licensing with some hoping to be building first of a kind systems in the next few years. Russia and China are further along the development line.

They use a range of technologies; some use components from existing larger reactors or the aviation industry, some use more novel components such as heat tubes to remove the heat. All of these reactors are designed to be accident tolerant, they can be used to produce heat or electricity and some are combined with molten salt energy stores to balance supply and demand.

It was claimed that the NuScale Advanced Small Reactor with 12 (or 4 or 6) 77 MWe units would have a site fence emergency planning zone (I’ll wait to see the ONR judgement on that!) and no radioactive release in normal operation, events or decommissioning.

A joint study which shows small nuclear being cost-competitive was cited (https://www.oecd-nea.org/jcms/pl_51110/projected-costs-of-generating-electricity-2020-edition?details=true). A representative of the WNA put forward the view that the world should concentrate its efforts into a smaller number of design concepts (I agree) and that international harmonisation of reactor design approval was required (not very likely in my opinion).

All of the speakers agreed that the demand for electricity will rise, outstripping the capacity of renewables, as it is increasingly used for transport and domestic heating while the burning of hydrocarbons becomes less acceptable. (Estonia has an additional issue in that its grid connections to Russia are expected to be cut in 2025 and they want to move away from dirty shale gas that they currently burn).

The initial target market is remote communities with a need for district heating and electricity although industrial uses, mining, disaster response, hospitals, campuses, military bases, data centres, desalination, and hydrogen production were all mentioned as potential users.

A question about competition from solar power/wind power and batteries was dodged. But a later speaker stated that small grids with wind and solar would benefit from a nuclear component providing reliable generation and also the “spinning metal” required to control frequency and voltage and also reported an ability to black start (without grid supplies) some micro-reactors.

Interestingly all speakers were more fluent when discussing the potential market than when discussing operators. If these reactors are to penetrate markets as single, remote units it will not on sites with 500+ nuclear skilled employees. Getting licensed to operate them will have to be no more difficult than getting licences to run industrial process plant or they will run into difficulty. Will the regulators accept local “semi-skilled” operators with remote technical support?

Canada’s action plan for SMR was the subject of a panel discussion. It introduced the Candu Users Group (COG) and its Small and Modular Reactor Group. Canada has a proud history in nuclear technology and now has a large industry of strategic importance. The action plan (www.Smrroadmap.ca) has 53 recommendations which have translated to 497 actions. This is a broad coalition of 210 partners.

The Canadians have identified three streams of effort; fast development of SMRs with the potential to replace coal generation (a requirement of Canada’s environmental policy), the development of advanced reactors for a variety of purposes including use of used fuel, and the development of very small SMRs (vSMR) to replace diesel in off-grid situations (remote communities and industrial sites).

The Canadian Nuclear Safety Commission is readying itself for the SMR programme with recruitment, a regulatory framework and reports on the potential issues. Their aim is to ensure safety and social acceptance without putting barriers in the path of progress.

The coherence and comprehensiveness of the Canadian plan is impressive. If only the UK could do something along the same lines.

This was an interesting day and provided ample evidence that there is a market position for small and micro reactors, with small reactors feeding national grids, process heat and hydrogen production and micro reactors providing power to remote communities and industries. There seem to be no insurmountable technology issues. The issues will be development finance and public acceptability and then the costs of ownership. Canada and Russia have advantages from obvious domestic markets at the high cost end. China has the advantage of a diverse nuclear industry and seemingly no limit to development funds. The UK obviously has the technical ability in this area with its commercial nuclear industry and nuclear powered submarine programme but it lacks the niche markets, clear funding and national strategy. There will be more in the market for multiple players. The UK will have to work hard to get a slice of that market.

The remote conference was not without technical issues and the posing of questions by text during the talk couldn’t replicate post-talk discussions. But the presentations and Q&As were available to review after the event.

I am grateful to Nuclear Engineering International for organising this event and to the speakers for their efforts. Next time I’d prefer to attend in person but this was a very welcome interlude in a lockdown.

Keith Pearce, Feb 2021

 

 

 

 

 

 

 

IAEA Integrated Regulatory Review Service (IRRS) visits ONR

In October 2019 there was an IAEA Integrated Regulatory Review Service (IRRS) visit to the UK. Its report can be found <here>.

The IAEA state that: “The Integrated Regulatory Review Service helps host States strengthen and enhance the effectiveness of their regulatory infrastructure for nuclear, radiation, radioactive waste and transport safety.

IRRS teams evaluate a State’s regulatory infrastructure for safety against IAEA safety standards. The teams compile their findings in reports that provide recommendations and suggestions for improvement, and note good practices that can be adapted for use elsewhere to strengthen safety. Mission reports describe the effectiveness of the regulatory oversight of nuclear, radiation, radioactive waste and transport safety and highlight how it can be further strengthened”. <here>

Prior to the visit the UK authorities conducted a self-assessment and presented a preliminary action plan and supporting documents. The IRRS team, which consisted of 18 senior regulatory experts from 14 IAEA Member States, 2 IAEA staff members and 1 IAEA administrative assistant, and 3 observers, reviewed these and a number of other documents before their visit and then spent two very busy weeks in the UK. This included interviews with 16 regulatory bodies and governmental departments.

Of particular interest to me are the references to emergency planning.

The mission commented that the “emergency planning zones established under REPPIR 2019 are not fully in alignment with the requirements of GSR part 7”. They recommend that the “Government should review the UK EP&R framework to explain how the requirements of GSR Part 7 are met in terms of planning zones and distances, and if any gap exists develop appropriate regulatory requirements”.

We must remember that GSR part 7 is IAEA advice and its section 2 states that it is “established in addition to and not in place of other applicable requirements, such as those of relevant binding conventions and national laws and regulations”. It goes on to say that where there is conflict between the GSR-7 and other requirements “the government or the regulatory body, as appropriate, shall determine which requirements are to be enforced”. I would expect that the ONR would have to champion UK regulation over IAEA advice.

We know that the UK “planning zones” do not match those of the IAEA. The UK zones have developed over many years and have, in the past, suited the UK emergency planning framework. REPPIR-19 was an opportunity to undertake a review of planning zones but it was an opportunity missed. The current system of a DEPZ with a torturous definition and an arbitrary outline planning zone does nobody any favours.

GSR-7 defines a precautionary action zone (PAZ) where arrangements are made to implement urgent protective actions and other responses before any significant release in order avoid or to minimize SEVERE DETERMINISTIC effects. This is severe accident territory and a release profile consistent with older designs of contained reactors for which a containment failure after several days of heating up was conceivable. So the PAZ as described in GSR-7 does not seem to make a great deal of sense in the modern world.

The next IAEA zone is the urgent protective action planning zone (UPZ). This is an area where arrangements have been made to initiate urgent protective actions and other response actions, if possible before any significant release of radioactive material occurs, on the basis of conditions at the facility, and after a release occurs, on the basis of monitoring and assessment of the radiological situation off the site, in order to reduce the risk of stochastic effects. This is broadly similar to the plans at many British sites where some protective actions are initiated on declaration and then thought is given to extending their scope and range if conditions merit it. It is important to realise that, in the UK, the default protective action areas are contained within the DEPZ but not defined by it.

The IAEA have an extended planning distance (EPD), beyond the urgent protective action planning zone, for which arrangements are made to implement further protective actions if monitoring and assessment on the day show that they may reduce stochastic effects if implemented within a day to a week or up to a few weeks following a significant radioactive release. UK outline planning and the gap between the automatic protective action zone and the DEPZ, sort of covers this zone.

Finally the IAEA define an ingestion and commodities planning distance (ICPD) beyond the extended planning distance where plans are in place to protect the food chain and water supply. That this zone is missing in the UK regulation does not mean that the relevant protective actions are not given the attention they deserve. The control of potentially contaminated food and drink is covered in REPPIR-19 (it is part of the operator’s consequence report and mentioned throughout guidance).

The “zones” are a bit arbitrary; are a planning tool and are best reserved for describing the national concept of operations to be applied to a fleet of reactor sites rather than to a particular site. Excellent emergency plans could be written without any use of the terms DEPZ and OPZ. What really matters is that the emergency plan is capable of initiating sensible default protective actions without delay and then rapidly considering the situation and responding to the particular characteristic of the emergency as those characteristics emerge.

I’d prefer to see a process in which the protective actions comes first and the zones second. Sensible plan compontents include:

  • On-site. UK plans tend to be quiet about what happens to the people (possibly several hundred) on the site. I’ve heard reservations about evacuating the site despite the fact that it is probably the only sensible thing to do because it will alarm sheltering residents. Cooping employees up in “mustering stations” i.e. the works canteen does not seem viable beyond a few hours and provides them with little protection.
  • An automatic protective action plan where shelter/exclusion and stable iodine are pre-planned in detail and initiated without discussion on declaration over an area likely to require them in a reasonably foreseeable emergency. (This could be a keyhole shape informed by the wind direction on the day).
  • A deliberative protective action plan that looks at how the protective actions of shelter and stable iodine could be extended further downwind if required and under what circumstances. This plan should detail the monitoring required to support decision making, the decision making process and how the protective actions will be achieved in a timely manner.
  • An agricultural precautionary protective action plan, where thought is given to how far downwind food interventions might be needed as an automatic action and as a deliberated action, what these might be and how they might be achieved. Informing farmers of the implications of this would be part of the public information cycle.
  • An evacuation plan looking at the circumstances under which authorities might want to evacuate areas close to the site (including the potentially hundreds of people on the site) and how it could be done.
  • A communication plan considering how people in the area will be informed of the plans and their parts in them, before any event and how they will be alerted and advised on the day. 

The US concepts of “plume exposure zone” and “ingestion pathway emergency planning zone” are rather more logical than the IAEA ones.

Neither the GSR-7 or REPPIR-19 planning zones definitions are ideal. Since REPPIR-19 has recently been introduced and the planning zones all reviewed there is likely to be little appetite in the UK to make any changes so it will be interesting to see how the ONR cope with this recommendation.

Plant Data

Another observation made by the mission was that “ONR does not have previously agreed format for plant data and information transfer during an emergency” coupled with the suggestion that “ONR should consider establishing pre-defined communication with the operating organizations in terms of plant data and other information during emergencies”.

The big questions here are “what plant data would be useful to ONR?” and “What would they do with it if they had it?”

If ONR were going to analyse plant data in real time and use it to generate advice to the local responders and the national government they would have to greatly extend their expertise in reactor accident management. This would only be a good idea if (a) there is something worth measuring i.e. there are parameters such as temperature, pressure, radiation levels, flow rates that can give the responders better knowledge of what is happening and what is likely to happen next (b) that data is measured and displayed somewhere (c) the ONR know what it means and will definitely be there to interpret it and (d) we don’t really trust the operator to correctly analyse and report the situation.

If ONR just need the data to be better informed spectators then I’d rather not bother.

I remember talking around this subject several times in relation to the rather primitive Magnox reactors. The conclusion was that there were very few parameters that were useful and could be measured and transmitted after a major cooling circuit failure and ignition of a fuel channel fire or two and unless they had happened there wasn’t really a problem. We always thought it would be different with PWRs which have far more instruments and loss of cooling accident sequences with periods where temperatures and pressures could be rising and threatening containment integrity.

RCIS

Another observation was that “The RCIS provides ONR with adequate infrastructure to respond in emergencies and its staff has been increased significantly in recent years. However, ONR does not have an overarching emergency response plan that defines its response objectives, the organizational response structure and functions, how the response actions are coordinated within the RCIS and its external stakeholders, etc. There are RCIS procedures for each position; however, these procedures are not linked together with an overarching document. The new ONR management system, under development, does not currently include a sub-process of ONR EP&R capability maintenance”.

It is a bit surprising that ONR has such a large structure and has recently extended it without actually articulating its objectives. I wonder if everyone has the same view about what it is for.

The mission goes on to observe that “the ONR does not have an overarching emergency response and preparedness plan to coordinate the response functions and maintain response capability within the RCIS. The action plan identified the ONR does not have a formal training and qualification programme for its staff responding to an emergency” and suggests that “The ONR should consider integrating its response arrangements into a response and preparedness plan and formalize training and qualification of emergency response staff”. This could be summarised as “if you are going to do something, understand why you are doing it, work out how you are going to do it and make sure your people know how to do it on the day”. On the face of it, this is sensible advice. 

Having been on both sides of this type of exercise I recognise that only a small fraction of the worth of the exercise is held in the final report. Being on the receiving side and trying to justify your plans and planning process against a polite but sustained challenge from a team of experts who are used to looking at things differently forces you to think deep in a way that the day job seldom does. You learn a lot.

Similarly being on the away team you read reports and think you’ve found gaps but, in discussion, you become to realise that different is not wrong and often where you see gaps you’ve missed the filling in a different component of the plan. They do some things, maybe a lot of things differently to you and many of them they do better than you. Everybody learns, everybody wins.

Keith Pearce, January 2021

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.

What is the case for the nuclear emergency planning community’s snobbishness about improvised respiratory protection for the general public?

In my many years as an emergency planner in the nuclear industry I’ve never heard a real debate about respiratory protection as a public protective action in the event of an accidental atmospheric release of radioactivity. It has always been dismissed because without proper masks and fit testing the protection factors offered are compromised.

In 1981 the IAEA [1] identified that respiratory protection was one way to reduce dose uptake in workers and members of the public. It recognised that high levels of protection require properly designed and fitted devices and realised that these would only be available to those with planned roles in a response. They accepted that if any use is to be made of such measures by the public, the simple equipment and techniques to be employed can only be of a very rudimentary nature.

They provided a quite extensive table of filtration factors for common materials. This included the finding that 16 layers of man’s cotton handkerchiefs provides a geometric mean efficiency of 94.2% against aerosols of 1-5 μm particle size – a protection factor not to be sneezed at. At eight layers the efficiency drops to 88.9%. A single bath towel is worth 73.9%.

The public, they said, “can be advised to use such simple items while proceeding to take shelter, and possibly during sheltering. Similar precautions could be recommended while members of the public were being evacuated from a contaminated area”.

In 2002 the US NCR published a document [2] which suggested that improvised respiratory protection can be used as a secondary protective action that can be used to provide a nontrivial level of additional protection. They also provide a table of protection factors.

In 2007 IAEA stated that [3] “Improvised respiratory protection (e.g. a wet cloth over the mouth and nose) has been shown to be effective but it has not been demonstrated that the public will apply it effectively during an emergency. Improvised respiratory protection should not be assumed to provide adequate protection from an inhalation hazard and therefore its implementation should not be allowed to interfere with evacuation or sheltering”. This does not say that improvised respiratory protection should not be recommended under any circumstances; it just says it should not be used instead of shelter or evacuation.

The latest advice on the protection of the public in the event of a nuclear accident from PHE [4] makes no mention at all of RPE, improvised or otherwise. This publication suggests a dose reduction factor of 0.6 for inhalation dose from shelter in place over the period of a release.

So why have we taken improvised respiratory protection out of our tool box of techniques to reduce public dose? It seems to offer protection factors at least comparable with shelter in place for particulate activity.

We worry about golf courses and caravan parks within our DEPZs where shelter in place is considered likely to be ineffective. Could we at least provide a supply of half decent face masks with the stable iodine tablets we store at these establishments as a secondary protection while thinking about evacuation?

Does the Covid-19 experience that shows that large fractions of the population will wear face masks when advised and has made them far more available to the public change our current attitude?

 

  1. IAEA, Safety Series No. 55, Planning for Off-Site Response to Radiation Accidents in Nuclear Facilities
  2. US NCR, Perspectives on Reactor Safety, NUREG/CR-6042, Rev. 2 SAND 93-0971
  3. IAEA Safety Standards Series No. GS-G-2.1, Arrangements for Preparedness for a Nuclear or Radiological Emergency (2007), https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1265web.pdf
  4. PHE, Public Health Protection in Radiation Emergencies, PHE-CRCE-049, (2019).