1. Introduction

Radioactivity can be of natural or artificial origin. It originates from the transformation of the structure of matter which emits ionising rays (alpha, beta, gamma) that represent a major danger to man and the environment. Depending on the strength of the ionising radiation received, one may distinguish between serious biological damage provoking apparent lesions (burns, organic lesions) and delayed biological damage, the effects of which show after several years in the guise of cancer or hereditary genetic malformations.
It is therefore important not to expose human beings and the environment to ionising rays by preventing or limiting all unnecessary rise in the radiation level or by reducing this to the minimum.
Depending on the characteristics of the radiation phenomenon, contamination may be temporary and localised or long lasting and affecting vast regions, according in particular to the prevailing meteorological conditions (spread of particles by the wind). The origins are most diverse and may arise in the first instance from the production, transport and storage of radioactive substances, from a nuclear accident or even a terrorist act, from the fall of a satellite, a fault in a nuclear power station, and also from the irresponsible storage of nuclear waste and weapons.
The use of nuclear weapons constitutes the ultimate disaster or threat to mankind. The primary and secondary radioactivity (fall-out) provoked by such weapons is complemented by the destructive effects of electromagnetic radiations, luminous and thermic, and the mechanical effects of the pressure which are proportionate to the weapon's power and the altitude at which it explodes.

2. Preventive and protective measures

In the present state of scientific and technical development, it is possible to prevent and protect from the harmful consequences of radioactivity. To this end, a law will specify the measures to be respected for protecting humans and the environment from the accidentaI or deliberate (criminal) escape of ionising radiations from the various known sources. In other words, it is necessary to legislate as regards protection against radiation (radioprotection) and the peaceful use of nuclear energy and, if need be, the protection of the population in case atomic weapons are used on the national territory or abroad in situations of armed conflict.
Basic protection against radiation (radioprotection) consists in obliging all users or owners of radioactive substances of any sort, or those responsible for installations and instruments emitting ionising radiations, to take all measures which experience requires to protect the life and physical integrity of persons exposed to radiation.
This results in precise obligations concerning the following:
- Determining and respecting dosage limits of exposure to radiation.
- Laying down medical measures for persons exposed to radiation because of their profession.
- Medical applications of radiation.
- Responsibility of enterprises, particularly as regards research in the technical uses of radioactivity and disposaI of radioactive waste.
- Observation of the environment and protection of the population should radioactivity increase.
- Checking the radioactivity of food products.
Protecting the population, the environment and the areas surrounding nuclear power plants when radioactivity reaches a dangerous level can only be achieved reliably through the implementation of permanent and complementary protective measures.
The intervention and alarm organisations established for this purpose also enable the population to be protected during non-conventional wars (use of atomic or chemical weapons).
The organisation of intervention in case of increased radioactivity should in principle be directly subordinated to the government (Ministry of Interior) which ensures the overall coordination of preventive and protective measures. An alarm and information centre ensures continuous monitoring and assessment of the surrounding radioactivity in collaboration with the regional and transboundary authorities and the competent enterprises and security services. Its main task, for which it uses a countrywide network of radiation detection equipment, is to establish intervention measures mainly as regards radioactivity and toxic chemical substances. The civil protection service sounds the alarm by means of its network of sirens, whilst guidance on how to react and behave is provided to the general public by the national radio.
The security of nuclear plants is ensured mainly by a series of precautions, such as the enclosure of combustible elements, the reactor's pressure tank, the steel security casing and the concrete security fence round the plant. When a serious accident occurs, such as the emission of rare gases and particles, a distinctive alarm system can be triggered within an area of a 5 to 20 kms radius, either simultaneously over the whole area or by individual sectors.

3. Intervention and rescue measures

Should an accident endangering humans and the environment by ionising rays occur, the operator of the installation and the responsible authorities immediately implement planned intervention measures:
- Dealing as quickly as possible with the causes of the accident and triggering the security measures capable of reducing the damaging effects.
- Informing the federal, regional and local authorities immediately.
In its capacity as the permanent radioactivity monitoring organ, the national alarm centre will be alerted first to enable the intervention organisation to proceed with an assessment of the radiological situation by means of the various services and devices in existence, and to propose which protection measures to implement.
It is important to immediately warn the population of any great increase in radioactivity and to publicise the official rules of behaviour which it is expected to follow. The highest degree of protection consists in taking refuge in the civil protection shelters or basements and in respecting the principles of individual and common protection.
In the event of a nuclear disaster, such as the explosion of a nuclear weapon, the management of protection, search, rescue and assistance (supplies, medical assistance, evacuation) operations at the local or regional level is the responsibility of the political authorities and their management organs which ensure the coordinated use of the available civil and military means of intervention required (equipment, material etc.). As regards radioactivity, technical coordination will be ensured by specialists in nuclear protection which should be available at all levels and be part of ail intervening bodies. International cooperation wiII be ensured through the International Atomic Energy Agency (IAEA) which is based in Vienna (Austria).

4. Instructions for the population

4.1 General precautions and safety measures relating to a potential danger

- Find out about and respect the regulations regarding the production, transport, handling and storage of radioactive substances, and take note of the symbol "danger-radioactive" shown on containers.
- Know the acoustic radioactivity alarm signals and the way to react (behaviour).
- Always keep a family emergency kit ready. This should include identity papers, personal documents and personal medicines. Also stock sufficient supplies to last for a few days, in case you are instructed to stay indoors.
- Plan and organise your probable stay in a civil protection shelter or a basement, especially if living in the neighbourhood of a nuclear power plant.
- Farmers and livestock owners should study the special recommendations on how to react and behave in case of a dangerous increase in radioactivity.

4.2 When the level of radioactivity increases

- Keep calm, do not panic.
- Listen to the radio and respect the suggested rules of behaviour.
- Stay in your house, in the civil protection shelter or the basement if possible. Close the air vents. Otherwise, stay inside, close all doors and windows, seal off all exterior openings and turn off the ventilation, air conditioning and heating.
- If outside, protect your mouth and nose with a wet cloth and seek refuge in the nearest shelter or building.
- Do not telephone as this overloads the system.
- Follow the orders of the civil protection, fire service, police, or other intervening services.
- Eat only food stored inside a building, such as tinned food or preserves and bottled water and drinks. In principle tap water remains drinkable, but respect official advice.
- Assemble cattle in a barn or stable and shut all openings leading outside. Store enough forage and water to last several days, and protect them from radioactive dust by cIosing all air vents and covering these with blankets or plastic sheeting.
- Avoid going into the stricken area and do not use cars so as not to slow down emergency vehicles.
- Should a nuclear explosion occur, shelter behind a very solid wall if you are outside. If this is not possible, lie down in a ditch or behind an embankment, face the ground and protect your face with your arms. Do not remain in a vehicle.

4.3 After the accident

- Obey the instructions of the authorities and the intervening organs (civil protection).
It is unlikely that an evacuation of the population will be necessary. Evacuation would be decided at the highest political level of the government, which would then organise it and involve civil and military personnel and their required resources. Respect the orders and implementation modalities given by the authorities.
- Taking all necessary precautions, help neighbours and persons in difficulty such as the injured, children and the aged, and collaborate if need be with the intervening services.