A three-year study by the Radiological Protection Institute of Ireland (RPII) found the day-to-day running of the plants would pose no health risk here.
And it said even in a worst-case scenario, where the most serious kind of accident was combined with the least favourable weather conditions, the maximum radiation dose likely to be received by members of the public was still well within safety limits.
However, the RPII did warn that in such a scenario — an event with a one in 33m chance of occurring — people would have to stay indoors for up to two days and long-term monitoring of agricultural produce would have to take place.
RPII chief Dr Ann McGarry said despite the low risks, vigilance was necessary. “It is important that we remain focused on the need to maintain and constantly review Ireland’s emergency plans to deal with the consequences of any nuclear accident abroad.”
Britain announced in 2009 it had selected eight sites for new nuclear power sites to be built by 2025. Five of those sites are on Britain’s west coast, the nearest just over 100km from Ireland.
Planning permission has only been granted for one so far at Hinkley Point in southern England, and An Taisce is taking a legal challenge to it, claiming Britain breached regulations by failing to take into account the potential impact on Ireland.
Environment Minister Phil Hogan received the RPII report on Monday.
“Minister Hogan and officials in the department will examine it and use the details of the report to further engage with UK officials to ensure that the interests of Ireland continue to be strongly represented,” said his department.
The report estimated the radiological impact of normal operations at the proposed plants and concluded the extra dose of radiation likely to be received by people here was half a unit per year.
The dose received by the average person here from natural sources such as radon gas, cosmic rays, fish consumption and X-rays is 4,000 units per year and a further 1,000 units from artificial sources is considered safe. The annual safe dose for people working directly with radioactive materials is put at 20,000 units.
Five hypothetical serious accidents were examined and in the most serious, compounded by east winds and heavy rain, the RPII estimates people who did not stay indoors would receive 18,000 units while the radioactive plume passed overhead and more if food controls were not observed.
“That’s still less than the 20,000 limit for people working with radioactive material,” Dr McGarry said. She added the level of radiation at which health issues were likely to occur was 100,000 units. In all cases, discharges to the Irish Sea — even equivalent to what happened after the Fukushima incident in Japan — were considered no risk to health.