Safety of Nuclear Power Plants

Safety of nuclear power plants with nuclear reactors must be assured in order to achieve a common goal – to protect the human being, public and the environment from radiological hazards. This goal can be achieved by assuring nuclear safety of a nuclear facility, which in turn can be reached by assuring required technical safety and radiation protection. The safety assurance goal can be achieved after an operator and regulatory authority define management responsibility, properly allocate safety management responsibilities, assess the impact of the human factor, etc.

General safety assurance principles scheme

1. General safety assurance. To protect the human, public and the environment from hazards by creating and maintaining efficient protection from radiological hazards.
2. Nuclear safety assurance objective. Actions which shall be taken in order to protect the human, public and the environment from radiological hazards:
   • by ensuring normal operation of a nuclear facility;
   • by preventing incidents and accidents;
   • by mitigating consequences caused by incidents and accidents.
3. Technical safety assurance objective:
   • to take all reasonable practical measures in order to avoid accidents.
4. Radiation protection assurance objective:
   • to ensure that ionizing radiation exposure or the amount of planned radionuclide emissions does not exceed the established limits and is as low as possible at any stage of the life cycle of a nuclear facility;
   • to ensure application of radiation protection measures for employees, population and the environment in case of an accident.
5. Safety management:
   • management responsibility is assigned;
   • activity quality and its assurance is being implemented;
   • the impact of the human factor is assessed;
   • appropriate response in case of an accident is ensured.

In-depth protection is one of the most important safety assurance principles.

Safety of nuclear power plants shall be assured by consistently implementing the in-depth protection principle based on the barrier system, which prevents ionizing radiation and radioactive substances from spreading in the environment, and by using a system of technical and organisational measures, which protects these barriers, maintains their efficiency, and directly protects the population.

Reactor safety barriers

1. First safety barrier – nuclear fuel matrix.
2. Second safety barrier – strong fuel rod cladding made from zirconium alloy.
3. Third safety barrier – reactor vessel and the borders of the primary reactor coolant loop.
4. Fourth safety barrier – pressure-resistant and hermetic reactor containment manufactured of steel or reinforced concrete.