1986 Chernobyl disaster Nuclear energy policy of the United States

the 1986 disaster in chernobyl, ussr considered worst nuclear disaster, date. on 25 april 1986, during routine maintenance, crew @ chernobyl began preparing test of reactor s turbine. during test, site experienced loss of main electrical power supply because of loss of power, automatic shutdown mechanisms failed, , reactor started become unstable. chernobyl operators tried cool rods inserting them reactor core, large power surge occurred. believed design flaw in rods.

this power surge combined hot fuel rods touching water in reactor caused fuel fragmentation along rapid steam production , increase in pressure. led fuel rods rupture, , safety protocols reactor core not withstand damage of 3–4 of fuel rod assemblies. resulting pressure inside core forced covering plate of reactor dislodge itself, rupturing fuel channels , jamming control rods, time, half-way down. resulting steam incident caused many of emergency cooling circuits malfunction. led large fission explosion released radioactive materials atmosphere. in period of few seconds, second explosion occurred caused graphite fragments of fuel ruptured rods blasted atmosphere, although debate still exists, scientists believe caused zirconium-steam reactions

chernobyl radiation map 1996 cia handbook

according world-nuclear.org, 2 workers died result of explosions. graphite (of which, quarter of 1200 tons estimated have been ejected) , fuel became incandescent , started number of fires, causing main release of radioactivity environment. total of 14 ebq (14 x 1018 bq) of radioactivity released, on half of being biologically-inert noble gases.

following explosion, hundreds of tons of water per hour poured reactor douse fires releasing radioactive smoke. however, abandoned after half day, prevent water flooding units 1 , 2. next 8 days, 5000 tons of boron, dolomite, sand, clay , lead dropped helicopter onto burning core in effort extinguish blaze , limit release of radioactive particles.

aside 2 initial deaths, officially, 28 more died in following weeks. after, 336,000 people evacuated after explosion , fire. eradiated ash, dust, , smoke traveled across of europe including russia, ukraine, , belarus. there heated debate on official number of deaths, illnesses , subsequent birth defects caused plant s meltdown. estimated number of deaths potentially resulting accident vary enormously; world health organization (who) suggested reach 4,000 while greenpeace report puts figure @ 200,000 or more. according who, mid-2005, 50 deaths directly associated disaster.

a 1979 anti-nuclear protest in harrisburg, pennsylvania after 3 mile island incident