Chernobyl Accident - Appendix 1: Sequence of Events

During the course of a safety system test being carried out just before a routine maintenance outage, Chernobyl 4 was destroyed as a result of a power transient on 26 April 1986.

The accident at Chernobyl was the product of a lack of safety culture. The reactor design was poor from the point of view of safety and unforgiving for the operators, both of which provoked a dangerous operating state.

 

Chernobyl Accident - Appendix 2: Health Impacts

During the course of a safety system test being carried out just before a routine maintenance outage, Chernobyl 4 was destroyed as a result of a power transient on 26 April 1986.

The health effects of the Chernobyl accident have been the subject of extensive study by health professionals and unprecedented speculation and exaggeration by parts of the media. This Appendix summarises two authoritative and expert assessments of the situation, and provides links to two others.

Early Soviet Reactors and EU Accession

Following the 1986 Chernobyl accident, safety concerns over early Soviet reactor designs intensified. As a condition of accession to the European Union, eight Soviet-designed reactors were closed. Sixteen nuclear power reactors of early Soviet design are still operating: one in Armenia and the rest in Russia

Earthquakes and Seismic Protection for Japanese Nuclear Power Plants

Earthquakes and Seismic Protection for Japanese Nuclear Power Plants: Nuclear facilities are designed so that earthquakes and other external events will not jeopardise the safety of the plant. In France for instance, nuclear plants are designed to withstand an earthquake twice as strong as the 1000-year event calculated for each site. It is estimated that, worldwide, 20% of nuclear reactors are operating in areas of significant seismic activity. The International Atomic Energy Agency (IAEA) has a Safety Guide on Seismic Risks for Nuclear Power Plants. Various systems are used in planning, including Probabilistic Seismic Hazard Assessment (PSHA), which is recommended by IAEA and widely accepted.

 

Fukushima: Fuel Ponds Background

Used fuel needs to be cooled and shielded. This is initially by water, in ponds. After about three years under water, used fuel can be transferred to dry storage, with air ventilation simply by convection. Used fuel generates heat, so the water is circulated by electric pumps through external heat exchangers, so that the heat is dumped and a low temperature maintained.

Fukushima: Radiation Exposure

No harmful health effects were found in 195,345 residents living in the vicinity of the plant who were screened by the end of May 2011. All the 1,080 children tested for thyroid gland exposure showed results within safe limits.

Fukushima: Reactor Background

The Fukushima Daiichi reactors are GE boiling water reactors (BWR) of an early (1960s) design supplied by GE, Toshiba and Hitachi, with what is known as a Mark I containment.

Nuclear regulation & regulators

List of nuclear regulatory organizations

Safety of Nuclear Power Reactors - Appendix

Some energy related accidents since 1977.