An on-site fire drill

It is not possible for a nuclear reactor to explode like an atomic bomb because of the low degree of fuel enrichment. However, it remains necessary to guard against the risk of release of radioactive products with nuclear safety based on the following principles:

	Multiple containment: many barriers to radioactivity release.
	Redundancy and diversity of systems: many duplication of systems, some are of different working principles for a safety task.
	A fail-safe approach: a fault will lead a system into a safe conditions.

The objective of nuclear safety is to protect the public and the environment against the dispersal of radioactive substances. This is achieved by various means to ensure the normal functioning of a nuclear facility to prevent incidents and accidents, and to mitigate their consequence should they occur.

Safety depends on the reliability of the equipment, the expertise and the action of the people and the efficient organisation of work covering the full lifespan of a nuclear facility.

To guarantee a high level of safety, there must be numerous and independent provisions to guard against envisaged failures. Should one provision fail, the remaining ones must be capable of avoiding the consequence of an accident. This is known as the defence in depth concept.

Staff must go through stringent radiation monitoring procedures when entering and leaving the restricted areas.

The nuclear industry has analysed the risks and taken steps to ensure a very low level of risks from a nuclear power station compared with our daily activities. External factors such as fire, earthquake, high winds, flooding and aircraft crash are considered in the design.

Defence in Depth
Safety Culture
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