For about 60 years, there has been a strong awareness of the potential hazard of both nuclear power reactors and the release of radioactive materials from generating electricity with nuclear power.
As in other industries, the design and operation of nuclear power plants aims to lessen the likelihood of accidents, and avoid major human aftereffects when they occur.
The evidence over six decades shows that nuclear power is a safe means of generating electricity. The risk of accidents in nuclear power plants is low and declining. The consequences of an accident or terrorist attack are minimal compared with other commonly accepted risks. Radiological effects on people of any radioactive releases can be avoided.
In the 1950s, attention turned to harnessing the power of the atom in a controlled way, as demonstrated at Chicago in 1942 and subsequently for military research, and applying the steady heat yield to generate electricity.
This naturally gave rise to concerns about accidents and their possible effects. However, with nuclear power, safety depends on much the same factors as in any comparable industry: intelligent planning, proper design with conservative margins and back-up systems, high-quality components and a well-developed safety culture in operations.
The operating lives of reactors depend on maintaining their safety margin. A particular nuclear scenario was loss of cooling which resulted in melting of the nuclear reactor core, and this motivated studies on both the physical and chemical possibilities as well as the biological effects of any dispersed radioactivity. Those responsible for nuclear power technology in the West devoted extraordinary effort to ensuring that a meltdown of the reactor core would not take place, since it was assumed that a meltdown of the core would create a major public hazard, and if uncontained, a tragic accident with likely multiple fatalities.
In avoiding such accidents, the industry has been very successful. In over 16,000 cumulative reactor-years of commercial operation in 33 countries, there have been only three major accidents to nuclear power plants – Three Mile Island, Chernobyl, and Fukushima – the second being of little relevance to reactor design outside the old Soviet bloc.
Of all the accidents and incidents, only the Chernobyl and Fukushima accidents resulted in radiation doses to the public greater than those resulting from the exposure to natural sources. The Fukushima accident resulted in some radiation exposure of workers at the plant, but not such as to threaten their health, unlike Chernobyl.
Apart from Chernobyl, no nuclear workers or members of the public have ever died as a result of exposure to radiation due to a commercial nuclear reactor incident. Most of the serious radiological injuries and deaths that occur each year – which account for about 2-4 deaths and many more exposures above regulatory limits – are the result of large uncontrolled radiation sources, such as abandoned medical or industrial equipment.
It should be emphasized that a commercial-type power reactor simply cannot under any circumstances explode like a nuclear bomb because the fuel is not enriched beyond about 5%, and a much higher enrichment is needed for explosives.
The International Atomic Energy Agency (IAEA) was set up by the United Nations in 1957. One of its functions was to act as an auditor of world nuclear safety, and this role was increased greatly following the Chernobyl accident. It prescribes safety procedures and the reporting of even minor incidents.
Its role has even been strengthened since 1996. Every country which operates nuclear power plants has a nuclear safety inspectorate and all of this work closely with the IAEA.
While nuclear power plants are designed to be safe in their operation and secure in the event of any malfunction or accident, no industrial activity can be represented as entirely risk-free. Incidents and accidents may happen, and as in other industries, will lead to progressive improvement in safety. Those improvements are both in new designs, and in upgrading of existing plants.
The safety of operating staff is a prime concern in nuclear plants. Radiation exposure is minimized by the use of remote handling equipment for many operations in the core of the reactor. Other controls include physical shielding and limiting the time workers spend in areas with significant radiation levels. These are supported by continuous monitoring of individual doses and of the work environment to ensure very low radiation exposure compared with other industries.
The use of nuclear energy for electricity generation can be considered extremely safe. Every year several thousands of people die in coal mines to provide this widely used fuel for electricity. There are also significant health and environmental effects arising from fossil fuel use.
