Construction of NPP is not a significant risk for the environment and safety of the population; as compared with the total risks, its contribution is very low. The topic of nuclear accidents is however closely followed by the media because its consequences generally hit a larger number of people at once, just like a transport aircraft accident. In the case of statistical representation of the number of deaths per GWh produced, nuclear energy is however not more dangerous than other forms of energy production and industrial activity.
The risk of any human industrial activity can never be excluded 100%. The objective is to minimize these potential risks.
Nuclear energy is carefully monitored and controlled above-standard as compared with other human activities, which may also lead to loss of human life.
Accidents at the nuclear power plants at Three Mile Island (USA, 1979), Chernobyl (USSR, 1986), Fukushima (Japan, 2011) became the impetus for the introduction of additional technical and organizational safety measures focused on increasing safety for the population. The Fukushima NPP withstood spontaneous forces that were not counted on at the time of its design. In connection with the radiation, the accident in Fukushima is not directly associated with even a single loss of life; all the reactors were shut down automatically. The impacts rather concern the mental condition of the evacuated persons.
In the nuclear energy sector, the blocks currently represent the Best Available Techniques (BAT). These are the newest NPP projects that unlike the previous generations manifest higher technological, safety and economic parameters.
Current power plants that are ranked in the generation II category form the backbone of world's nuclear energy and their technical condition usually makes it possible to extend operations beyond the initial project assumptions. More than half the blocks comprise type PWR light-water reactors (which include the VVER blocks built in the former Czechoslovak Socialist Republic and continue in operation in the Czech Republic and the Slovak Republic). The power plants currently use the best available techniques based on proven generation II technical solutions with a number of evolutionary elements. The major differences as compared with the 2nd generation are:
- standardised design that shortens the licensing period for the individual power plants, the essential investment costs and construction time,
- simplified, but at the same time, safer and more robust design that allows easier operation and increasing operating reserves,
- higher availability (90% and above), higher net efficiency (up to 37%) and longer service life (minimum 60 years),
- lower accident risk with substantial damage to the reactor core (substantially below 10-5/year),
- higher resistance to external impacts,
- allowance for higher spending of the fuel (higher fuel utilisation of up to 70 GWd/tU) and reduction of the potential volume of generated waste,
- extension of the time the fuel remains in the reactor core by usage of burnable absorbers (by up to 24 months).
By improvement of existing systems (e.g. higher pressure resistance of the containment building, usage of dual containment for higher protection against circulation in containment and external impacts) the probability of melting of the nuclear core and massive leak has been reduced by at least one stage as compared with generation II reactors. At the same time, the hypothetical impacts of accidents on the environment have been reduced.
Primary safety target
New nuclear power plants will be designed to ensure compliance with basic safety objectives in line with the latest requirements of the International Atomic Energy Agency IAEA. The fundamental safety objective is to protect people, society and the environment against the adverse effects of ionizing radiation.
The fundamental safety objectives will be considered in all phases of the nuclear facility, i.e. planning, siting, design, production, construction, commissioning, operation through retirement, including the transport of radioactive materials and radioactive waste management.
Primary safety requirements
Nuclear power will be implemented in accordance with the legislation of the Czech Republic as well as the current internationally recognized safety requirements relevant to nuclear technology. The mandatory requirements are as follows:
- The laws and implementing legislation of the Czech Republic, including international treaties and conventions to which the Czech Republic is a party.
- Safety Standards of the IAEA (at the level of basic safety principles and safety requirements of the IAEA SF-1, IAEA SSR) and WENRA safety requirements.
For a new nuclear power source the following radiological criteria, which are based on the most advanced WENRA, IAEA and ICRP requirements, among other things, shall apply:
- during normal and abnormal operation of a new nuclear power plant, the authorized limits for emission of radionuclides into the environment shall not be exceeded; for a representative person, the optimisation dose limit that relates to radiation from the discharges of all operated blocks in one location,
- no event during which the core does not melt will lead to the release of radionuclides requiring the safeguard measures of sheltering, iodine prophylaxis and evacuation of residents anywhere in the vicinity of the new nuclear power plant,
- for a postulated accident with core melting, such design measures shall be taken so that evacuation of the immediate vicinity is not necessary and long-term restrictions in food consumption need not be implemented; accidents with core melting, which could lead to early or large leaks shall be practically excluded.