Safety plan: a well-oiled system to cope with every contingency
From the time power plants are designed, while they are in operation and throughout their decommissioning, safety precautions govern the generation of nuclear power to rule out incidents affecting people and the environment. Thanks to a safety system that is continuously being improved, the probability of a nuclear accident is negligible. EDF and the public authorities have nevertheless jointly set up a comprehensive procedure to manage emergency situations.
Two complementary emergency plans to ensure optimum responsiveness
EDF and the public authorities in France have drawn up two closely coordinated emergency plans to respond to a nuclear crisis. It clearly defines the people involved and their responsibilities to ensure maximum efficiency.
The Internal Emergency Plan (PUI) covers action to be taken at the site. The manager of the power plant is responsible for its implementation under the oversight of the Nuclear Safety Authority (ASN). Under this plan, on-call staff are dispatched to bring the facility into a safe condition, ensure minimum consequences for people and property, and provide first aid to casualties if need be.
The Special Emergency Plan (PPI) covers all measures taken outside the site to protect the population and monitor the environment if there is a risk of radioactive discharge. The PPI is initiated by the Prefect of the administrative department where the nuclear plant is located. Depending on the type of event and the way it unfolds, the Prefect may decide, on the recommendation of the ASN, to take three types of preventive measures: confining the population to a safe place, distributing iodine tablets, or evacuation. These decisions apply to a defined area around the power plant and depend on the severity of the incident. In all cases, the public authorities continuously keep the public abreast of the situation.
Nearly a hundred people are on call at a nuclear power plant at all times
Initiation of these safety plans also entails mobilisation of EDF’s national crisis organisation, the ASN and its technical support, and the Radiation Protection and Nuclear Safety Institute (IRSN).
Nuclear crisis: precautionary measures through iodine tablets
In the event of a discharge of radioactivity to the environment and if the foreseeable thyroid dose is 50 millisieverts (mSv) or more, the Prefect can order iodine tablets to be distributed to the population.
An iodine tablet protects the thyroid by saturating it with stable iodine, thus preventing radioactive iodine from being taken up. If radioactive iodine is inhaled or ingested, it is simply eliminated by natural means.
The public authorities make these iodine tablets available to people living within a 10 km radius of nuclear power plants. People are asked to pick them up at a pharmacy in exchange for a coupon issued to the individual person.
The most recent distribution of iodine tablets to people living near all French nuclear power plants, organised jointly by the government, the Nuclear Safety Authority (ASN) and EDF, began in January 2016.
INES scale: measuring the severity of a nuclear event
Used since 1991, the International Nuclear Event Scale provides a common reference framework that can be understood by everyone involved to indicate the severity of a nuclear incident or accident.
On this scale, events are ranked from 0 to 7 depending on their scope and on three criteria:
Consequences outside the nuclear site
Consequences inside the site
Damage to the facility's in-depth lines of defence
Note that the INES scale is not a tool for assessing or comparing events. Its purpose is to foster information-sharing with the media and the public as well as among the 60 countries or so that use the scale.