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Nuclear Reactors Safety

The safest method of generating electricity is from nuclear power. Full details of why this is so are given in www.uic.com.au/nip14.htm The Chernobyl disaster could only occur under state socialism which is why Greenpeace deny this fact.

There have been two major accidents in the history of civil nuclear power generation: Three Mile Island (USA 1979) where the reactor was severely damaged but radiation was contained and there were no adverse health or environmental consequences. Chernobyl (Ukraine 1986) where the destruction of the reactor by explosion and fire killed 31 people and had significant health and environmental consequences.

These two significant accidents occurred during more than 10,000 reactor-years of civil operation. Only the Chernobyl accident resulted in loss of life or radiation doses to the public greater than those resulting from the exposure to natural sources.

A commercial power reactor cannot under any circumstances explode like a nuclear bomb. Nuclear power plants are designed to shut down automatically in an earthquake.

The Three Mile Island accident in 1979 demonstrated the importance of such systems. The containment building which housed the reactor prevented any significant release of radioactivity, despite the fact that about half of the reactor core melted. By way of contrast, the Chernobyl reactor did not have a containment structure like those used in the West or in post-1980 Soviet designs.

The terrorists attack on the World Trade Center in New York focused attention on the safety of nuclear power plants in a similar circumstance. In fact, such a scenario has always been contemplated and nuclear reactors would be more resistant to such assaults than virtually any other civil installations.

The disaster at Chernobyl in the Ukraine was the result of major design deficiencies, the violation of operating procedures and the absence of a safety culture. The accident destroyed the reactor, killed 31 people, 28 of whom died within weeks from radiation exposure. It also caused radiation sickness in a further 200-300 staff and firefighters, and contaminated large areas of Belarus, Ukraine, Russia and beyond. It is estimated that at least 5% of the total radioactive material in the Chernobyl-4 reactor core was released from the plant, due to the lack of any containment structure. Most of this was deposited as dust close by. Some was carried by wind over a wide area.

About 130,000 people received significant radiation doses (i.e. above internationally accepted ICRP levels) and are being closely monitored. About 800 cases of thyroid cancer in children have been linked to the accident. Most of these were curable, though about ten have been fatal. No increase in leukaemia or other cancers have yet shown up, but some is expected. The World Health Organisation is closely monitoring most of those affected.

The Chernobyl accident was a unique event and the only time in the history of commercial nuclear power that radiation-related fatalities occurred.

An OECD expert report on it concluded that "the Chernobyl accident has not brough to light any new, previously unknown phenomena or safety issues that are not resolved or otherwise covered by current reactor safety programs for commercial power reactors in OECD Member countries". A major international program of assistance has been carried out by the OECD, IAEA and Commission of the European Communities to bring early Soviet-designed reactors up to near western safety standards, or at least to effect significant improvements to the plants and their operation.

The designs for new nuclear plants contain numerous safety improvements based on operational experience. The first two of these new reactors began operating in Japan in 1996. The main feature they have in common (beyond safety engineering already standard in Western reactors) is passive safety systems, requiring no operator intervention in the event of a major malfunction.

COMPARISON OF ACCIDENT STATISTICS IN PRIMARY ENERGY PRODUCTION (Electricity generation accounts for about 40% of total primary energy)

Fuel electricity Immediate fatalities 1970-92 Who? Normalised to deaths per TWy*
Coal 6400 Workers 342
Natural gas 1200 Workers and public 85
Hydro 4000 Public 883
Nuclear 31 Workers 8

* Basis: per million MWe operating for one year, not including plant construction, based on historic data which is unlikely to represent current safety levels in any of the industries concerned.

Source: Ball, Roberts & Simpson, Research Report # 20, Centre for Environmental & Risk Management, University of East Anglia, 1994; Hirschberg et al, Paul Scherrer Institut, 1996; in: IAEA, Sustainable Development and Nuclear Power, 1997; Severe Accidents in the Energy Sector, Paul Scherrer Institut, 2001).