fuel price, and other factors were borne by consumers rather than suppliers. Many countries have now liberalised the electricity market where these risks, and the risk of cheaper competitors emerging before capital costs are recovered, are borne by plant suppliers and operators rather than consumers, which leads to a significantly different evaluation of the economics of new nuclear power plants. Following the 2011 Fukushima Daiichi nuclear disaster, costs are likely to go up for currently operating and new nuclear power plants, due to increased requirements for on-site spent fuel management and elevated design basis threats. Environment The environmental impact of nuclear power results from the nuclear fuel cycle, operation, and the effects of nuclear accidents. The greenhouse gas emissions from nuclear fission power are small relative to those associated with coal, oil, gas, and biomass. They are about equal to those associated with wind and hydroelectric. The routine health risks from nuclear fission power are very small relative to those associated with coal, oil, gas, solar, biomass, wind and hydroelectric. However, there is a "catastrophic risk" potential if containment fails, which in nuclear reactors can be brought about by over-heated fuels melting and releasing large quantities of fission products into the environment. The public is sensitive to these risks and there has been considerable public opposition to nuclear power. Even so, in comparing the fatalities for major accidents alone in the energy sector it is still found that the risks associated with nuclear power are extremely small relative to those associated with coal, oil, gas and hydroelectric. For the operation of a 1000-MWe nuclear power plant the complete nuclear fuel cycle, from mining to reactor operation to waste disposal, the radiation dose is cited as 136 person-rem/year, the dose is 490 person-rem/year for an equivalent coal-fired power plant. The 1979 Three Mile Island accident and 1986 Chernobyl disaster, along with high construction costs, ended the rapid growth of global nuclear power capacity. A further disastrous release of radioactive materials followed the 2011 Japanese tsunami which damaged the Fukushima I Nuclear Power Plant, resulting in hydrogen gas explosions and partial meltdowns classified as a Level 7 event. The large-scale release of radioactivity resulted in people being evacuated from a 20 km exclusion zone set up around the power plant, similar to the 30 km radius Chernobyl Exclusion Zone still in effect. Subsequent scientific assessment of the health impacts of radiation has