‘Shelter in place’ advised by nuclear incident review
A radioactive plume caused by an incident at one of the Cotentin Peninsula nuclear sites was the worst case scenario considered by the UKHSA in its review of the likely risks of a nuclear incident.
Three areas were part of its consideration – the Orana La Hague nuclear fuel reprocessing site, Flamanville nuclear power station and Cherbourg naval dockyard, where nuclear submarines are berthed.
‘The biggest risks to the populations of the Channel Islands would come from the release of radioactive material into the air from these sites,’ said the review.
They considered the size of any release, what radioactive material might be involved and how likely it would be for the wind to blow it towards the islands.
A computer model, taking wind records over the a five-year period, was used to examine how the islands might be affected. It looked at 850 different times of day across the seasons.
Prevailing winds are from the west and south-west, which would take any plume away from the islands most of the time. But even if a plume did head for the islands it might change direction or be dispersed, meaning low levels of radiation.
The best action anyone could take in such a situation would be to ‘shelter in place’ said the review – staying indoors with windows and doors shut and any vents or air conditioning turned off.
‘While a plume of radioactive material is passing overhead, sheltering will reduce the amount of radioactive material that people breathe into their bodies.’
Although stable iodine tablets can be used to reduce or stop the uptake of radioactive iodine, the local authorities have decided that they were not going to stockpile these.
They would only have effect on radioactive iodine that gets into the body. Another idea considered was evacuating islanders but this was dismissed by the report, since it would need to happen before any plume reached the islands.
There would need to be advice on what people could eat and drink due to possible contamination.
Of the various plumes looked at, at least half would have led to islanders receiving a very low or zero dose of radiation.
‘Also, we found that even if a plume does pass over the islands, the radioactive material in it might be so dispersed that radiation doses are low, and no protective actions would be necessary.’
