[Fredrik Dahl and Alister Doyle: "Japan radiation release lower than Chernobyl (2011/03/23 13:46 EDT) by Reuters]

(Reuters) - The release of two types of radioactive particles in the first 3-4 days of Japan's nuclear crisis is estimated to have reached 20-50 percent of the amounts from Chernobyl in 10 days, an Austrian expert said Wednesday.


The calculations published by Austria's Central Institute for Meteorology and Geodynamics may add to growing concern in Japan and elsewhere over the contamination of food products such as milk and vegetables in areas near the Japanese reactor site.


Tuesday, France's IRSN radiation protection and nuclear safety institute estimated leaks of radiation from the Fukushima plant crippled by the March 11 earthquake and tsunami represented about 10 percent of those from Chernobyl, the world's worst nuclear disaster, in 1986.


Comparisons are hard because Chernobyl's reactor blew apart, rather than leaking more slowly. Chernobyl's pollution blew over land in Europe while much of the contaminated air from Fukushima's crippled reactors has dispersed over the Pacific.


The Austrian institute's Dr Gerhard Wotawa stressed the two isotopes from Fukushima he had sought to estimate -- iodine-131 and caesium-137 -- normally make up only one tenth of total radiation.

オーストリアの研究所のDr Genhard Wotawaは、福島から放出された放射性同位元素、ヨウ素131とセシウム137は、全放射線量を10%増加させるにすぎないと強調した。

Based on measurements made at monitoring stations in Japan and the United States, Wotawa said the iodine released from Fukushima in the first three-four days was about 20 percent of that released from Chernobyl during a ten-day period. For Caesium-137, the figure could amount to some 50 percent.

日本および米国のモニタリングポストの計測値に基づいて、Dr Wotawaは福島から最初の3〜4日間で放出されたヨウ素131は、チェルノブイリが10日間で放出した量の20%程度であると述べた。セシウム137については、その数字は50%程度になる。

The International Atomic Energy Agency said Wednesday Japanese authorities had told the Vienna-based agency that radiation dose rates at the plant were decreasing, although the overall situation remained serious.


One U.N. study has estimated Chernobyl, in Ukraine, may over time cause 4,000 to 9,000 extra deaths from cancer.

And there are big differences in the handling of the crises.

"At Chernobyl, the population was not generally aware that the accident had happened," said Malcolm Crick, Secretary of the U.N. Scientific Committee on the Effects of Atomic Radiation.

"People in the nearby town of Pripyat were watching the fire from just a kilometer or so away. They were evacuated a day or so later," he said, adding that children kept drinking milk despite risks of contamination.

"In Japan, there was a precautionary evacuation early on," he said, adding "it's too early to make a real assessment of the overall impact."


「チェルノブイリでは、人々は事故が起きたことを知らなかった。近くのプリピャチの人々は数キロメートル先の火災を見ていた。彼らは1日以上たってから避難した。汚染のリスクにもかかわらず、子供たちは牛乳を飲んでいた。日本では予め避難が行われていた。被害の全容を評価にするには、まだ早すぎる。」と国連の Scientific Committee on the Effects of Atomic RadiationのSecretaryであるMalcolm Crickは述べた。

Japanese authorities also distributed units of stable iodine which can help protect against radioactive iodine.


Edwin Lyman, senior scientist at the U.S.-based Union of Concerned Scientists Global Security Program said the levels were worrying:

"The fact that radiation releases are approaching the level they did in Chernobyl is a cause for concern, a sign of the severity of the accident that's already taken place," said Lyman, especially given the way Chernobyl exploded.

"One has to remember that there's still no evidence that the containment structures of the damaged (Fukushima) reactors 1, 2, and 3 have been significantly breached, which is a difference from Chernobyl where the confinement structure was destroyed in the very early stages of the accident."

米国を本拠地とする Scientific Committee on the Effects of Atomic RadiationのシニアサイエンティストEdwin Lymanは懸念を述べる。「放射線放出量がチェルノブイリのレベルに近づいていることが懸念音理由であり、それは既に起きた事故の深刻さを示している。しかし、被害を受けた福島1,2,3号機の格納容器が顕著に壊れているという証拠はまだない。これは事故の初期段階で格納容器が壊れたチェルノブイリとの違いのひとつである。」

Wotawa said it was difficult to make day-by-day comparisons with Chernobyl, but he added: "For cesium and iodine ... the source terms (amounts released from the two accidents) are not so different."

He said iodine -- linked to cancer if found in high doses -- and cesium were both "volatile substances" which escape relatively easily when there are nuclear accidents.

Dr Wotawaは「チェルノブイリと、日々の比較をするのは困難である。しかし、セシウムとヨウ素については、2つの事故の発生量は大きく違っていない。多量に摂取すると癌に関連するヨウ素と、セシウムに関しては、いずれも"揮発物質"であり、原子力事故では比較的容易に漏れ出す」と述べた。

Only minor traces of radiation have been detected in countries outside Japan, but the U.N. nuclear watchdog this week said "high levels of contamination" have been measured around the Fukushima plant, about 250 km north of Tokyo.

Japanese authorities advised parents Wednesday not to let infants drink tap water in the capital because of raised radiation levels, and the United States became the first nation to block some food imports from Japan.



posted by Kumicit at 2011/03/24 08:32 | Comment(0) | TrackBack(0) | Earthquake | このブログの読者になる | 更新情報をチェックする



コメント: [必須入力]