An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A severe accident in a nuclear reactor which is caused by a major failure in the reactor cooling circuit leading to the melting of the reactor core. Without coolant, the core would overheat so that the uranium fuel would melt. If the core continued to heat up, the steel walls of the core would also melt. If the molten core escaped from the containment housing of the reactor, large amounts of highly radioactive materials would be released into the atmosphere. The radioactive contamination of the air, water, and soil can have disastrous consequences for life.

→ melt; down, M.E. doun, from O.E. dune "downward," short for adune, ofdune, from a-, of "off, from" + dune "hill."

Forugodâxt, from foru- "down, downward; below; beneath," as in forurixtan, forunešastan, foruraftan (Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" cf. Skt. pravát- "a sloping path, the slope of a mountain") + godâxt past stem of godâxtan, godazidan → melt.