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 weapons and Ukraine by Russia. Ukraine would also have struggled with replacing the nuclear weapons once their service life expired, as Ukraine did not have a nuclear weapons program. In exchange for giving up its nuclear weapons, Ukraine received financial compensation, as well as the security guarantees of the Budapest Memorandum. On December 5, 1994 the leaders of Ukraine, Russia, Britain and the United States signed a memorandum to provide Ukraine with security assurances in connection with its accession to the NPT as a non-nuclear weapon state. The four parties signed the memorandum, containing a preamble and six paragraphs. The memorandum reads as