Lecture13-16

U the star goes into free fall unl it hits the fermi

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Unformatted text preview: as bad as possible? meltdown, hydrogen explosions, mul;ple reactor catastrophe, burning spent fuel rods good prevailing winds large region is too radioac;ve to inhabit??? 46 could easily have been prevented, need to keep the power on What Went Wrong u༇  Earthquake, Tsunami: much larger wave than had been considered in safety study. o  considered only recorded tsunamis o  but evidence existed of large tsunamis 600 years ago. (bad mistake) u༇  Reactors were shut down due to earthquake. o  o  o  o  u༇  emergency generators turned on to keep water flowing through rectors fuel rods produce heat from nuclear decay of fission products and must be cooled con;nuously tsunami flooded generators (behind a seawall but at sea level) there could have been much safer backup power The reactors should have been flooded with sea water but the electric company and the government did not want to ruin the reactor. (big mistake) o  by the ;me they did flood the rectors, they had melted down u༇  u༇  There were hydrogen explosions inside all of the opera;ng reactors, rupturing the containment vessels. Spent fuel rods were kept in pools of water near the reactors. o  The water in the pools evaporated and was not replenished (big mistake) o  Some of the rods caught fire u༇  The power company and government did not keep the public informed. 47 u༇  u༇  u༇  The 2012 analysis of the amount of intermediate and long lived radioac;vity released from all the Fukushima Daiichi reactors taken together, is about 10- 20% of that released from the Chernobyl disaster, when comparing the two disasters together.[103][104] The total release from the en;re Fukushima disaster, in terms of Cesium- 137(which along with stron;um- 90 are the two primary substances preven;ng Chernobyl being inhabited,[105]) is ~1.5×10^16 Becquerels (Bq) of Cesium- 137 released,[106] in contrast the amount released from Chernobyl, was ~8.5x10^16 Bq of Cesium- 137.[107] which is an ac;vity produced by 24 kilograms of Cesium- 137.[105] Another notable difference between the two accidents is that, unlike Chernobyl, all the Japanese reactors were situated within concrete containment vessels, which contributed to the Japanese accident releasing vastly less stron;um- 90, americium- 241 and plutonium, which were amongst the radioisotopes released at Chernobyl.[103][107] In terms of the most biologically hazardous short lived radioisotope iodine- 131, 5x10^17 Bq of Iodine 131 were released from the Fukushima disaster.[106] In comparison to the release at Chernobyl ~17.6x10^17 Bq of iodine- 131 was released.[107] As this substances decays away to become a stable nuclei rapidly, due to its short half life of 8.02 days. There is only a short ;me available for human exposure to occur, aRer ten half life...
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