Types of incident
Although nuclear plants are designed to ensure that accidents affecting the public are highly unlikely, it is prudent to have plans to deal with them. Accidents have occurred, notably at Windscale (UK) in 1957, Three Mile Island (USA) in 1979 and Chernobyl (USSR) in 1986. Satellites containing radioactive materials have crashed to earth, as in Canada in 1978, while transport and military activities can lead to accidents, as can industrial and medical uses of radiation.
When radioactive materials are released in an accident, people can be affected in the following ways:
- through breathing
- direct radiation from radioactive materials carried in the air and deposited on surfaces
- ingestion (eating and drinking food and water containing radioactive materials)
What to do
Take the following action to reduce the effect:
Staying inside, with doors and windows closed, provides short-term protection from breathing in radioactive material in the air. It also gives protection from direct radiation from radioactive material in the air and on the ground.
Evacuation avoids relatively high, short-term exposure, by removing people from the affected area. As with other island communities, evacuation is unlikely to be an option for Jersey in these circumstances.
Iodine collects in the thyroid gland. If it is appropriate taking stable (non-radioactive) iodine tablets prevents this happening with radioactive iodine released in reactor accidents. Taking stable iodine is combined with sheltering or evacuation.
Radioactive material deposited on soil or grass, finds its way into food through crops and animals. It might be necessary to ban milk or other foods containing too much radioactive material.
Detection and monitoring
Radioactive material in an area can be measured in various ways, and there are a number of organisations and people with the specialist knowledge, skills and equipment to monitor these measurements.
By international agreement, Jersey will automatically receive warning of nuclear accidents abroad. As a back-up, automatic instruments throughout the United Kingdom and Europe form what is known as the Radioactive Incident Monitoring Network (RIMNET), which would detect and measure abnormal radiation levels. RIMNET is run by the UK Environment Agency and monitored in Jersey by the emergency planning officer.
Nuclear event scale
An International Nuclear Event Scale (INES) is used as a standardised way for promptly notifying the public about the seriousness of events reported at nuclear sites. No counter measures affecting the public would be likely below level 5. Examples: Chernobyl - Level 7; Three Mile Island - Level 5; Windscale Fire - Level 5.
Major accident 7
Serious accident 6
Accident with off-site risks 5
Accident mainly in installation 4
Serious incident 3
Below scale - no safety significance
Radioactive material released from sites overseas can affect the UK and the Channel Islands, as happened with Chernobyl in 1986.
The radiation doses from Chernobyl affecting people in the UK were small compared with background radiation. For several years in the UK, farmers in high laying areas, where heavy rain fell during the cloud’s passage overhead, were not allowed to sell sheep. These bans were intended to keep public radiation doses low.
Jersey and the UK have the RIMNET monitoring network to detect radioactive releases, as well as computer programs to predict their movement.
Other radiation accidents
Radioactive materials are widely used in medicine, industry, agriculture and research. Despite efforts to ensure safety, accidents do occasionally happen.
With radioactive materials being widely used, it is sometimes difficult to have formal emergency plans like those for nuclear accidents. There are arrangements to give the emergency services and the States scientific help when an incident occurs, and these are called NAIR (national arrangements for incidents involving radioactivity). The help comes from hospitals, and defence and nuclear sites.