Lincoln Journal Star
Experts who investigated Japan's nuclear crisis said Monday that a watchdog's oversight of the crippled plant's operator is still too lax, amid renewed public fear over a recent spate of safety problems. The Fukushima Dai-ichi plant has been plagued ...
Accident investigators say Japan nuclear safety plans too lax for crowded ...
Washington Post
TOKYO — Experts who investigated Japan's nuclear crisis said Monday that government oversight of the crippled plant's operator is still too lax, as public concern has grown over recent safety problems. A power failure last month caused by a rat that ...
讀了這篇應稍知核電廠不是台灣玩得起的.
Damaged Nuclear Plant in Japan Leaks Toxic Water
April 07, 2013
TOKYO — Tens of thousands of gallons of radioactive water leaked from a large underground storage pool at Japan’s
crippled nuclear plant, and thousands more gallons could seep out
before the faulty pool can be emptied, the plant’s operator said
Saturday.
The disclosure came a day after workers at the stricken Fukushima plant who were installing wire nets to keep rats away from a vital cooling system instead tripped that system, causing it to fail for the second time in weeks.
About 120 tons, or almost 32,000 gallons, of highly contaminated water appeared to have breached the inner protective lining of the pool at the Fukushima Daiichi plant, said the operator, Tokyo Electric Power Company. It was unclear how much of the water had made it through two additional layers of lining to reach soil, but radiation levels outside the pool have risen, a sign that some water is getting out, said the company, known as Tepco.
The leak highlights the daunting challenge of what to do with the huge amounts of contaminated water created by makeshift cooling systems at the plant, after a huge earthquake and tsunami knocked out its regular cooling systems two years ago in the worst nuclear accident since Chernobyl. Since then, Tepco has essentially been pouring water onto the damaged reactor cores and storage ponds to keep them from overheating.
As it is used for cooling, the water becomes so contaminated that it must be safely stored at the plant. Tepco said it was already storing more than a quarter-million tons of radioactive water in hundreds of tanks that seem to fill every available space at the plant, or in underground pools like the leaking one. With the decommissioning of the Fukushima plant likely to take decades, Tepco has said it expects the amount of radioactive water to keep growing, and possibly more than double within three years. The company has said it is building more storage space and new filtering facilities to clean the water.
The company said the leak appeared to be the biggest since the early months after the March 2011 disaster, when leaks allowed contaminated water to flow into the nearby Pacific Ocean. Tepco said that this time, it did not expect any of the toxic water to reach the sea, since the pool is half a mile from the coast.
Still, Tepco said it had begun pumping the remaining 13,000 tons of water out of the faulty pool and into a similar pool. The pools are like large ponds dug into the ground, protected by multiple layers of plastic sheets and covered with dirt.
Emptying the damaged pool could take five more days, the company said, during which time an additional 47 tons, or about 12,000 gallons, could leak.
The debris-strewn plant still relies on makeshift cooling systems, some of which were hastily put together in the accident’s frantic aftermath.
A blackout disabled cooling at four fuel pools last month, an event the company traced to a rat that might have gnawed on power cables and caused a short circuit. Engineers found its scorched body in a damaged switchboard.
Tepco has since installed mousetraps at the site and promised to plug holes through which rats and other rodents might enter buildings and gnaw on important equipment. It has also promised to speed up work to install backup power cables to the fuel pools.
But Friday afternoon, four workers using wire meshing to seal a space around electric cables caused a ground fault, or the accidental flow of current to the ground. No one was injured, but the ground fault shut off electricity to the cooling system at the No. 3 reactor fuel pool.
The spent-fuel pool went without fresh cooling water for almost three hours before cooling was restored late Friday. There was no imminent danger to the 566 nuclear fuel rods stored in the pool, according to the company. It would have taken at least two weeks for the pool to have risen above the safe level of 149 degrees Fahrenheit, Tepco said.
The disclosure came a day after workers at the stricken Fukushima plant who were installing wire nets to keep rats away from a vital cooling system instead tripped that system, causing it to fail for the second time in weeks.
About 120 tons, or almost 32,000 gallons, of highly contaminated water appeared to have breached the inner protective lining of the pool at the Fukushima Daiichi plant, said the operator, Tokyo Electric Power Company. It was unclear how much of the water had made it through two additional layers of lining to reach soil, but radiation levels outside the pool have risen, a sign that some water is getting out, said the company, known as Tepco.
The leak highlights the daunting challenge of what to do with the huge amounts of contaminated water created by makeshift cooling systems at the plant, after a huge earthquake and tsunami knocked out its regular cooling systems two years ago in the worst nuclear accident since Chernobyl. Since then, Tepco has essentially been pouring water onto the damaged reactor cores and storage ponds to keep them from overheating.
As it is used for cooling, the water becomes so contaminated that it must be safely stored at the plant. Tepco said it was already storing more than a quarter-million tons of radioactive water in hundreds of tanks that seem to fill every available space at the plant, or in underground pools like the leaking one. With the decommissioning of the Fukushima plant likely to take decades, Tepco has said it expects the amount of radioactive water to keep growing, and possibly more than double within three years. The company has said it is building more storage space and new filtering facilities to clean the water.
The company said the leak appeared to be the biggest since the early months after the March 2011 disaster, when leaks allowed contaminated water to flow into the nearby Pacific Ocean. Tepco said that this time, it did not expect any of the toxic water to reach the sea, since the pool is half a mile from the coast.
Still, Tepco said it had begun pumping the remaining 13,000 tons of water out of the faulty pool and into a similar pool. The pools are like large ponds dug into the ground, protected by multiple layers of plastic sheets and covered with dirt.
Emptying the damaged pool could take five more days, the company said, during which time an additional 47 tons, or about 12,000 gallons, could leak.
The debris-strewn plant still relies on makeshift cooling systems, some of which were hastily put together in the accident’s frantic aftermath.
A blackout disabled cooling at four fuel pools last month, an event the company traced to a rat that might have gnawed on power cables and caused a short circuit. Engineers found its scorched body in a damaged switchboard.
Tepco has since installed mousetraps at the site and promised to plug holes through which rats and other rodents might enter buildings and gnaw on important equipment. It has also promised to speed up work to install backup power cables to the fuel pools.
But Friday afternoon, four workers using wire meshing to seal a space around electric cables caused a ground fault, or the accidental flow of current to the ground. No one was injured, but the ground fault shut off electricity to the cooling system at the No. 3 reactor fuel pool.
The spent-fuel pool went without fresh cooling water for almost three hours before cooling was restored late Friday. There was no imminent danger to the 566 nuclear fuel rods stored in the pool, according to the company. It would have taken at least two weeks for the pool to have risen above the safe level of 149 degrees Fahrenheit, Tepco said.
福島核電站上百噸放射性污水泄漏
報道 2013年04月07日
東京——福島核電站的運營商上周六稱，這座已停產的核電站內的一個巨大的地下蓄水池已經泄漏了數萬加侖的放射性污水，在出現問題的水池被排空之前，可能還會有多達數千加侖的污水泄出。
事故發生的前一天，工人們正在受損嚴重的核電站安裝金屬絲網，以防止老鼠進入一處重要的冷卻系統。但工人的操作失誤引發冷卻系統斷路，導致該系統在幾周之內第二次未能正常運轉。
運營商東京電力公司（Tokyo Electric Power Company，簡稱東電）表示，大約有120噸，也就是近3.2萬加侖高度污染的污水似乎已經衝破福島第一核電站(Fukushima Daiichi plant)蓄水池的內部保護層。東電說，目前還不清楚，有多少污水已經衝破其餘兩道保護層，滲入土壤，不過，水池外的放射性濃度已經升高，這個跡象表 明，一些污水正在滲出。
污水泄露事件突顯了核電站在處理臨時冷卻系統產生的大量污水方面所遭遇的嚴峻挑戰。兩年前發生的福島核事故是切爾諾貝利核事故之後最嚴重的核事故， 當時，一場大地震和海嘯破壞了核電站的常規冷卻系統。自此之後，東電實際上一直把水傾倒進受損的反應堆堆芯和存儲池，以防止堆芯和存儲池過熱。
由於被用於冷卻反應堆，這些水受到了嚴重的污染，因此必須把它們安全地存儲在核電站內部。東電說，他們已把逾25萬噸的放射性污水存儲在數百個蓄水 罐內，這些裝置似乎佔據了核電站里所有能利用的空間，還有一些污水則貯存在地下蓄水池內，比如發生泄露的那一個。由於福島核電站可能需要幾十年才能完全拆 除，東電錶示，預計放射性污水水量將繼續上升，而且可能會在三年之內翻一番還多。東電已經表示，正在建造更多的存儲設施，以及新的過濾設施來凈化污水。
該公司表示，2011年3月災難發生後的幾個月里出現的泄漏事故導致污水流入附近的太平洋，而此次泄漏似乎是自上述事故以來最嚴重的一次。東電錶示，他們認為此次泄漏事故不會致使污水流入海洋，因為這個蓄水池距離海岸有半英里遠。
但東電錶示，該公司已經開始將剩餘的1.3萬噸污水從出現問題的水池抽出，然後灌入類似的水池。這些蓄水池通過掘地產生，它們受到多層塑料薄膜的保護，表層覆蓋著泥土。
該公司表示，抽空受損儲水池可能還需要五天時間，而在此期間，又可能會有47噸（約合1.2萬加侖）污染水泄出。
這座瓦礫遍布的核電站仍然要依靠臨時冷卻系統，而其中一些裝置是在核事故之後的混亂時期匆忙組裝而成。
上個月，斷電事故導致四個燃料池的冷卻系統陷入癱瘓。該公司追蹤發現，可能是一隻老鼠咬噬了電纜，引發短路。工程師在一個出現故障的配電盤中發現了燒焦的老鼠屍體。
此後，東電在核電站放置了捕鼠器，並承諾堵塞裂口，防止老鼠和其他嚙齒動物進入建築，咬噬重要設備。該公司還承諾加快速度，安裝連接燃料池的備用電纜。
但周五下午，四名工人在電纜周圍利用金屬絲網設置封閉區域時引發接地故障——電流意外與地面相接。沒有人受傷，但接地故障切斷了3號反應堆燃料池冷卻系統的電力供應。
周五晚些時候，冷卻系統恢復工作。在此之前，乏燃料池在將近三個小時的時間裡沒有冷卻水注入。據該公司透露，事故沒有對池中存儲的566根核燃料棒造成緊迫威脅。東電錶示，燃料池的溫度至少要兩周才會升高到超過149華氏度安全線的水平。
事故發生的前一天，工人們正在受損嚴重的核電站安裝金屬絲網，以防止老鼠進入一處重要的冷卻系統。但工人的操作失誤引發冷卻系統斷路，導致該系統在幾周之內第二次未能正常運轉。
運營商東京電力公司（Tokyo Electric Power Company，簡稱東電）表示，大約有120噸，也就是近3.2萬加侖高度污染的污水似乎已經衝破福島第一核電站(Fukushima Daiichi plant)蓄水池的內部保護層。東電說，目前還不清楚，有多少污水已經衝破其餘兩道保護層，滲入土壤，不過，水池外的放射性濃度已經升高，這個跡象表 明，一些污水正在滲出。
污水泄露事件突顯了核電站在處理臨時冷卻系統產生的大量污水方面所遭遇的嚴峻挑戰。兩年前發生的福島核事故是切爾諾貝利核事故之後最嚴重的核事故， 當時，一場大地震和海嘯破壞了核電站的常規冷卻系統。自此之後，東電實際上一直把水傾倒進受損的反應堆堆芯和存儲池，以防止堆芯和存儲池過熱。
由於被用於冷卻反應堆，這些水受到了嚴重的污染，因此必須把它們安全地存儲在核電站內部。東電說，他們已把逾25萬噸的放射性污水存儲在數百個蓄水 罐內，這些裝置似乎佔據了核電站里所有能利用的空間，還有一些污水則貯存在地下蓄水池內，比如發生泄露的那一個。由於福島核電站可能需要幾十年才能完全拆 除，東電錶示，預計放射性污水水量將繼續上升，而且可能會在三年之內翻一番還多。東電已經表示，正在建造更多的存儲設施，以及新的過濾設施來凈化污水。
該公司表示，2011年3月災難發生後的幾個月里出現的泄漏事故導致污水流入附近的太平洋，而此次泄漏似乎是自上述事故以來最嚴重的一次。東電錶示，他們認為此次泄漏事故不會致使污水流入海洋，因為這個蓄水池距離海岸有半英里遠。
但東電錶示，該公司已經開始將剩餘的1.3萬噸污水從出現問題的水池抽出，然後灌入類似的水池。這些蓄水池通過掘地產生，它們受到多層塑料薄膜的保護，表層覆蓋著泥土。
該公司表示，抽空受損儲水池可能還需要五天時間，而在此期間，又可能會有47噸（約合1.2萬加侖）污染水泄出。
這座瓦礫遍布的核電站仍然要依靠臨時冷卻系統，而其中一些裝置是在核事故之後的混亂時期匆忙組裝而成。
上個月，斷電事故導致四個燃料池的冷卻系統陷入癱瘓。該公司追蹤發現，可能是一隻老鼠咬噬了電纜，引發短路。工程師在一個出現故障的配電盤中發現了燒焦的老鼠屍體。
此後，東電在核電站放置了捕鼠器，並承諾堵塞裂口，防止老鼠和其他嚙齒動物進入建築，咬噬重要設備。該公司還承諾加快速度，安裝連接燃料池的備用電纜。
但周五下午，四名工人在電纜周圍利用金屬絲網設置封閉區域時引發接地故障——電流意外與地面相接。沒有人受傷，但接地故障切斷了3號反應堆燃料池冷卻系統的電力供應。
周五晚些時候，冷卻系統恢復工作。在此之前，乏燃料池在將近三個小時的時間裡沒有冷卻水注入。據該公司透露，事故沒有對池中存儲的566根核燃料棒造成緊迫威脅。東電錶示，燃料池的溫度至少要兩周才會升高到超過149華氏度安全線的水平。
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