I was interested to learn that the American system has a mechanism to respond to a situation where a nuclear power station cannot get adequate support from the local responders for their off-site plan. Their rules define “decline or fail” as a “situation where State or local governments do not participate in preparing offsite emergency plans or have significant planning or preparedness inadequacies and have not demonstrated the commitment or capabilities to correct these inadequacies in a timely manner so as to satisfy NRC licensing requirements”. (44 CFR 352.1)
The licensee seeks Federal assistance by submitting certification that a decline or fail situation exists to the host FEMA Regional Administrator explaining why assistance is needed and providing documentary proof that they have tried to rectify the situation themselves.
This is reported to FEMA Headquarters and the involved off-site organisations. The State and local governments have 10 days to submit a written report of their views and position and FEMA make a determination about whether or not a decline or fail exist within 45 days of the original communication.
The FEMA Deputy Administrator for the National Preparedness Directorate shall make a final determination as to whether Federal facilities and resources are needed. This process identifies what resources could be called on, the extent and purpose for which they can be called and the limitations on their use.
Interestingly it is assumed that the State and local authorities will contribute their full resources and exercise their authorities in accordance with their duties in a real event.
The Federal resources are to take care not to supplant State and local resources and only make good the impact of the decline or fail. FEMA will attempt to recover the costs incurred from the licensee and from the nonparticipating or inadequately participating State or local government.
In the UK REPPIR requires co-operation from various bodies and requires that the off-site plan be reviewed and tested but makes no mention of what happens if off-sites are deemed inadequate.
In the United States the Environmental Protection Agency issues “Protective Action Guidelines” (PAGs) which satisfy the same role that Emergency Reference Levels (ERLs) do in the United Kingdom. The Protective Action Guide (PAG) manual contains radiation dose guidelines that would trigger public safety measures, such as evacuation or staying indoors, to minimize or prevent radiation exposure during an emergency.
The 2017 PAG manual is a significant document (101 Pages) which has chapters devoted to:
Early phase protective action guides;
Emergency worker protection;
Intermediate phase protective action guides;
Planning guidance for the late phase.
For the early phase it provides a PAG for shelter in place or evacuation of the public of 10 to 50 mSv projected dose over four days. This is accompanied by a note that suggests that actions should start at 10 mSv projected dose and take whichever action or actions result in the lowest exposure for the majority of the population. This is broadly consistent with IAEA advice and UK practice although the UK ERLs are based on averted dose rather than projected.
The stable iodine PAG is 50 mSv to the infant thyroid from exposure to radioactive iodine.
Emergency workers should be limited to 50 mSv over the entire response or per year unless there are extreme circumstances (such as saving life or preventing a significant release).
The report warns that: “In the early phase, there may be little or no data on actual releases to the environment and responders may have to rely on crude estimates of airborne releases. Decision time frames are short and preparation is critical to make prudent decisions when data are lacking or insufficient.”
The report suggests that the public should be advised to cover their mouth and nose with “available filtering material” when particulate activity may be present. This advice is not given in the UK.
It is also suggested that where particulate activity is present but below the PAG level the public are advised to “stay indoors to the extent practical” to reduce their dose but make a judgement if they need to go out for any reason. Such advice is apparently given on days when air pollution is forecast to be bad. Again, this is not something I’ve heard mentioned in the UK.
A discussion about the relative merits of shelter in place and evacuation concludes that “Sheltering-in-place should be preferred to evacuation whenever it provides equal or greater protection. Sheltering-in-place followed by informed evacuation may be most protective”. It reports that populations that are aware of the evacuation alerting mechanisms and plans are more likely to successfully evacuate than unprepared populations and further reports that many areas are improving their communications processes and public training. The need to have special plans for needy groups such as schools, institutions and those without their own transport is noted.
On iodine tablets the report suggests that minimum doses for each age (weight) group is ideal but that, if this is too challenging logistically and in terms of communication, then a full dose can be given to all without great risk.
Interestingly it suggests that adults over 40 years old would only benefit from stable iodine if their projected thyroid dose is of the order of 5 Sv where it can be used to prevent hypothyroidism.
Stable iodine given to pregnant women also protects the foetus but repeat doses should be avoided if possible to prevent foetal thyroid complications. (In the UK it is expected that a single dose of stable iodine will be adequate because either the release will have stopped or the affected members of the public should be evacuated within the 24 hours that the first dose provides protection for).
Breast feeding mothers can reduce the radioiodine in their milk by taking the usual dose of stable iodine. This is useful for reducing the baby’s dose but does not protect them from directly inhaled radioiodine for which a small dose of stable iodine can be administered.
Section 2.3 discusses the process of estimating dose projections based on source terms, atmospheric dispersion and release prognosis. Section 2.4 discusses contamination and environmental monitoring.
Subsequent sections discuss the control and limitation of dose to responders and recovery workers and doses in the later phases of the event, including from food and water, once the release has stopped. Of interest is table 4-2 which summarises a discussion about the circumstances under which people can be allowed back into an area, either for remedial work, use of critical infrastructure, to access business and homes to recover property.
On the whole the advice given in this report is similar to that given in the NRPB’s ERL documents that are used in the UK. It contains some interesting and useful discussion.
The IAEA has published proceedings which present the outcome of a conference on decommissioning and environmental remediation (D&ER) programmes, at which challenges, achievements and lessons learned in the implementation of such programmes during the past decade were shared and reviewed (here).
An interesting presentation by Tadashi INOUE, Research Advisor to Fukushima Prefecture on Remediation (here) Session 4b No 11) which, if I understand it correctly, argues that, for the decontamination around Fukushima:
The lack of understanding of radiation in the general public was a barrier to the initial discussions and this helped sour the relationship between the people and the authorities.
The variety of players acting and publishing independently in the early stages caused confusion and insecurity. Better co-ordination of monitoring and interpretation should be sought from an early stage.
Target levels for decontamination and dose reduction should be set based on radiological, technical and sociological issues and within the ICRP 1mSv/yr – 20 mSv/yr band.
The development of a decontamination strategy is a priority. The highest contaminated areas are not necessarily the place to start rather the emphasis should be on dose reduction.
The acceptance of community and property owner is essential for the progress of remediation.
Gaining the trust of the people is made difficult by the number of different opinions being expressed in public. In Japan they seem to have more trust in academics than in officials.
Some of this learning may not apply in the UK due to differences in the behaviour of society.
The balance of centralised coordination of the monitoring and interpretation against independent work by various bodies will be hard to manage to optimise trust, understanding and joint decision making.
Finding a process where the trust of the residents can be developed through dialogue will take time and will be made difficult by the actions of some parties multiplied by the impact of broadcast abd social media. The level of anger expressed around the Grenfell Tower fire in London over shortcomings in the care offered to the survivors in the hours and weeks after the event and the media involvement in the Charlie Gard court case show how difficult the situation can get and how distracting the views of people outside as well as those inside the issue can be.
(All figures from Tadashi INOUE presentation to IAEA (Madrid, May 2016))