The Association of the Heads of the European Radiological protection Competent Authorities (HERCA) and Western European Nuclear Regulators’ Association (WENRA) have jointly considered cross border cooperation in the early stages of a nuclear accident. They propose a mechanism based on shared technical understanding, coordination and mutual trust.
A workshop is reported (here) which was attended by representatives from ONR and PHE CRCE. It is not known to what extent the UK participants agreed with the published conclusions of the workshop.
The aim of the project is to ensure that when an accident affects neighbouring countries the countermeasures recommended in each country are comparable as described in the figure above (taken from HERCA WENRA document). It was reported that some countries have clear guidance on how to set countermeasures that might make this harmonisation more difficult.
The report suggests that (Conservative) evaluation of the potential hazard area favours a common understanding and coherent communication internationally and helps to give early assurance to populations outside this area. It does not seem to have considered that an excessively large countermeasure zone would hamper the ability to focus resources on those in most need of support and may unduly inconvenience and worry people within the zones but relatively safe from the radiation hazard. This seems to go against the ICRP principle of justification that “any decision that alters the radiation exposure situation should do more good than harm” (ICRP 103, page 88).
The report states that “HERCA and WENRA consider that in Europe:
- evacuation should be prepared up to 5 km around nuclear power plants, and sheltering and ITB up to 20 km;
- a general strategy should be defined in order to be able to extend evacuation up to 20 km, and sheltering and ITB up to 100 km;
- nuclear and radiation safety authorities in Europe should continue attempts to promote compatible response arrangements and protection strategies amongst the European countries”.
It later explains that the 5 km evacuation and 20 km sheltering and taking of stable iodine prophylaxis is a precautionary approach for situations where core melt is judged possible. It also states (Section 8.2) that shelter is preferred to evacuation if the evacuation cannot be completed before the release starts.
The wider zones are stated to be appropriate where, in addition to core melt, the containment integrity is lost.
Since sheltering cannot be implemented for a very long duration, the report proposes that it should be prepared immediately but only implemented a few hours before the time of release. The report does not develop the discussion of the implications of a warning time. It would give an opportunity for people to collect stable iodine tablets from a local distribution point and to prepare for shelter but would also possibly trigger an uncontrolled evacuation and panic buying of food and bottled water. Great care should be taken when considering recommending shelter “once the release starts”.
Discussion.
The harmonisation of countermeasure advice across national borders in the event of a transnational release of radioactivity is clearly desirable. This can best be achieved with shared technical understanding, coordination and mutual trust but also requires the same decision making process when facing with an uncertain radiological situation and limited time to make and implement decisions. The approach of pre-agreeing on the largest area based on generic conservative decision making runs the risk of applying disproportionate countermeasures on the day and saddling society with disproportionate emergency preparation costs. A link to the site’s safety case seems much more appropriate.
It is not clear where this grouping’s remit for advising countermeasure distances comes from, the basis for their distances is unexplained as is how they relate to EURATOM and IAEA. So while their thoughts on cross-border cooperation and information exchange are valued, their thoughts on countermeasure distances do not seem to add value to the discussion.