Decision to Discontinue the Future Distribution of Iodine Tablets

3 April 2008

During 2002, iodine tablets, intended to be taken in the event of a major nuclear accident that might result in the release of radio-active iodine, were issued to each household.

Mary Harney TD, Minister for Health and Children has decided, on the basis of expert risk management advice, not to re-issue these tablets.

In 2002, Ireland was the only country to issue iodine tablets to each household and it is now recognised that the risks which may have existed then have now been substantially reduced. In particular, there was concern at the time about the vulnerability of the Calder Hall reactors on the Sellafield site: however, these reactors are no longer operational.

The decision not to re-issue iodine tablets has been taken on the basis of the low risk of a radio-active iodine release and in the context of best international practice which does not recommend general household distribution other than in the immediate vicinity of a nuclear reactor.

Use of iodine tablets following an accident at a nuclear facility.

A serious accident at a nuclear power plant may involve the release of a number of radioactive elements into the atmosphere - including radioactive iodine (also known as radio-iodine). When inhaled or ingested, radio-iodine tends to concentrate in the thyroid gland giving rise to high concentrations in this organ. High concentrations of radio-iodine in the thyroid gland increase a person’s risk of developing thyroid cancer. Iodine prophylaxis, or the administration of stable iodine (usually in the form of iodine tablets), reduces or prevents the uptake of radio-iodine by the thyroid gland.

Iodine tablets are effective in reducing the radiation dose from radio-iodine following a nuclear accident - they do not reduce the radiation dose from other radioactive elements. Staying indoors and controlling the consumption of contaminated foodstuffs are effective methods of reducing the radiation dose from all radioactive elements - including radio-iodine.

The International Atomic Energy Agency and the World Health Organisation have published guidance on the level of radiation dose that would indicate the need for stable iodine as an intervention measure. The Radiological Protection Institute of Ireland (RPII) uses this guidance in its assessment of potential protective actions for any future nuclear accident.

How likely is it that an accident at a nuclear facility abroad will require the use of iodine tablets in Ireland?

The threat of an accident at a nuclear facility abroad involving the release of a large quantity of radio-iodine has very much receded in recent years with the closure of two of the oldest and most vulnerable nuclear reactors in the UK, namely Calder Hall and Chaplecross. Sellafield does not pose a threat with regard to radio-iodine as the activities carried out there do not generate radio-iodine isotopes.

The closest nuclear power station to Ireland is the Wylfa Nuclear Power Plant in North Wales which is 114 km from the Irish coastline. As part of the RPII’s remit to provide advice and information to the Government on nuclear safety issues, the RPII visited the Wylfa Plant in late 2006. One of the key areas examined during the visit was the potential impact on Ireland of an accident or incident at Wylfa. Using the information made available to it, the RPII carried out a detailed analysis of different accident scenarios and concluded that, even in a worst case scenario, the use of iodine tablets would not be justified in Ireland following such an accident at Wylfa.

What are other countries doing?

Information from a number of countries indicates that Belgium, Canada, the Czech Republic, Finland, France, Germany, Luxembourg, Sweden and Switzerland have pre-distributed iodine in the vicinity of nuclear reactors - the area covered has ranged from 4 km to 20 km radius of the nuclear reactors. In the UK, the decision to pre-distribute rests with the local authority and it has only occurred in a limited number of cases and a 3 km radius has tended to be used.

What should householders do with their iodine tablets?

They should dispose of the tablets as normal household waste but they should not remove the tablets from the packaging material.