Steam explosion major cause of human fatalities in volcanic eruptions. The 1986 Chernobyl nuclear disaster in Soviet Union was feared to cause major steam explosion (and resulting Europe-wide fallout) upon melting the lava-like nuclear fuel through the reactor's basement towards contact with residue fire-fighting water and groundwater. The threat was averted by frantic tunneling underneath the reactor in order to pump out water and reinforce underlying soil with concrete. When a pressurized container such as the waterside of a steam boiler ruptures, it is always followed by some degree of steam explosion. A common operating temperature and pressure for a marine boiler
Nuclear power in Japan 2 worker deaths, one more exposed to radiation levels above legal limits and over 660 others received detectable radiation doses but within permissible levels, well below the threshold to affect human health. The Mihama Nuclear Power Plant experienced a steam explosion in one of the turbine buildings in 2004 where five workers were killed and six injured. There have been many nuclear shutdowns, failures, and three partial meltdowns which were triggered by the 2011 Tōhoku earthquake and tsunami. According to the Federation of Electric Power Companies of Japan, "by April 27 approximately 55 percent of the fuel in reactor unit