東京電力柏崎刈羽原発(2) 炉心溶融(融解)の危機? ジャパン・シンドローム 冷却水漏出?

一部の海外メディアは、今回の柏崎刈羽原発の事故を指して、「今回の日本の巨大地震は、すんでのところで、深刻な事故(たとえば、メルトダウン。炉心溶融、炉心融解)を引き起こし、数百万人が死亡する大惨事となるところだった。」と述べています。

名づけて、炉心融解を扱った原発映画「チャイナ・シンドローム」をもじって、「ジャパン・シンドローム」だそうです。

(日本から地球の裏側はブラジルですので、ブラジル・シンドロームになりそうな気もしますが、あまりにも分かりにくいのでそうならなかったのでしょうか。実際は、炉心融解によって圧力隔壁が破壊されれば、拡散により核分裂反応は停止、あるいは周囲の水と反応して水蒸気爆発を起こしますので、地球の反対側に到達することはありません)

さて、「ニュースでは、炉心融解の危機はなかったということになっている。ジャパン・シンドロームは言い過ぎだ。」と思われる方もいるかも知れません。炉心については、地震による損傷が懸念されていますが、本当のところは、炉心を開けて点検してみないとわからないのではないでしょうか?原子炉炉心の損傷の有無を確かめる点検作業の開始は9月以降、炉心の状況を含む被害の全容確認は早くとも秋以降になるということですが、すでにある程度はわかっている事柄があると推察しています。

たとえば、前回の記事の写真をみていたたくとわかるのですが、なぜ、多量の水蒸気が放出されたのでしょうか?今回のタイプの沸騰水型の原発は、、核分裂反応によって生じた熱エネルギーで軽水(いわゆる水)を沸騰させ、高温・高圧の蒸気として取り出し、タービン発電機によって発電させたのち、回収して再循環させています。この蒸気は、もちろん放射能を帯びています。写真の水蒸気は、炉心冷却水ではないのでしょうか?

今中哲二准教授(京都大原子炉実験所)は、以下のように指摘しています。
・(放射性)ヨウ素が大気中に放出されていることから、炉心内部にある燃料棒の破損が想定される
・配管のひびや、制御系回りのトラブルが発見される可能性もある

この放射性ヨウ素は、半減期が短いため、「炉心冷却水」が漏れたことを示唆しています。

CNNは、"A Japanese nuclear power plant ... leaked water containing radioactive materials from a reactor, according to the company running the facility."として、「反応容器から水が漏れた」と明記しています。

(引用開始)

Meltdown: The Japan Syndrome
Saturday, 21 July 2007
by Harvey Wasserman

The massive earthquake that shook Japan this week nearly killed millions in a nuclear apocalypse.

It also produced one of the most terrifying sentences ever buried in a newspaper. As reported deep in the New York Times, the Tokyo Electric Company has admitted that, “the force of the shaking caused by the earthquake had exceeded the design limits of the reactors, suggesting that the plant’s builders had underestimated the strength of possible earthquakes in the region.”
There are 55 reactors in Japan. Virtually all of them are on or near major earthquake faults. Kashiwazaki alone hosts seven, four of which were forced into the dangerous SCRAM mode to narrowly avoid meltdowns. At least 50 separate serious problems have been so far identified, including fire and the spillage of barrels filled with radioactive wastes.
There are four active reactors in California on or near major earthquake faults, as are the two at Indian Point north of New York City. On January 31, 1986, an earthquake struck the Perry reactor east of Cleveland, knocking out roads and bridges, as well as pipes within the plant, which (thankfully) was not operating at the time. The governor of Ohio, then Richard Celeste, sued to keep Perry shut, but lost in federal court.
The fault that hit Perry is an off-shoot of the powerful New Madrid line that runs through the Mississippi River Valley, threatening numerous reactors. The Beyond Nuclear Project reports that in August, 2004, a quake hit the Dresden reactor in Illinois, resulting in a leak of radioactive tritium. Nevada’s Yucca Mountain, slated as the nation’s high-level radioactive waste dump, has a visible fault line running through it.
More than 400 atomic reactors are on-line worldwide. How many are vulnerable to seismic shocks we can only shudder to guess. But one-eighth of them sit in one of the world’s richest, most technologically advanced, most densely populated industrial nations, which has now admitted its reactor designs cannot match the power an earthquake that has just happened.

In whatever language it’s said, that translates into the unmistakable warning that the world’s atomic reactors constitute a multiple, ticking seismic time bomb. Talk of building more can only be classified as suicidal irresponsibility.

Tokyo Electric’s behavior since the quake defines the industry’s credibility. For three consecutive days (with more undoubtedly to come) the utility has been forced to issue public apologies for erroneous statements about the severity of the damage done to the reactors, the size and lethality of radioactive spills into the air and water, the on-going danger to the public, and much more.

Once again, the only thing reactor owners can be trusted to do is to lie.


Prior to the March 28, 1979 disaster at Three Mile Island, the industry for years assured the public that the kind of accident that did happen was “impossible.”
Then the utility repeatedly assured the public there had been no melt-down of fuel and no danger of further catastrophe. Nine years later a robotic camera showed that nearly all the fuel had melted, and that avoiding a full-blown catastrophe was little short of a miracle.
The industry continues to say no one was killed at TMI. But it does not know how much radiation was released, where it went or who it might have harmed. Since 1979 its allies in the courts have denied 2400 central Pennsylvania families the right to test their belief that they and their loved ones have been killed and maimed en masse.

Prior to its April 26, 1986, explosion, Soviet Life Magazine ran a major feature extolling the virtually “accident-proof design” of Chernobyl Unit Four.

Then the former Soviet Union of Mikhail Gorbachev kept secret the gargantuan radiation releases that have killed thousands and yielded a horrific plague of cancers, leukemia, birth defects and more throughout the region, and among the more than 800,000 drafted “jumpers” who were forced to run through the plant to clean it up.
Since the terror attacks of September 11, 2001, the industry has claimed its reactors can withstand the effects of a jet crash, and are immune to sabotage. The claims are as patently absurd as the lies about TMI and Chernobyl.
So, too, the endless, dogged assurances from Japan that no earthquake could do to Kashiwazaki what has just happened.
Yet today and into the future, expensive ads will flood the US and global airwaves, full of nonsense about the “need” for new nukes.
There is only one thing we know for certain about this advertising: it is a lie.
Atomic reactors contribute to global warming rather than abating it. In construction, in the mining, milling and enriching of the fuel, in on-going “normal” releases of heat and radioactivity, in dismantling and decommissioning, in managing radioactive wastes, in future terror attacks, in proliferation of nuke weapons, and much much more, atomic energy is an unmitigated eco-disaster.
To this list we must now add additional tangible evidence that reactors allegedly built to withstand “worst case” earthquakes in fact cannot. And when they go down, the investment is lost, and power shortages arise (as is now happening in Japan) that are filled by the burning of fossil fuels.
It costs up to ten times as much to produce energy from a nuke as to save it with efficiency. Advances in wind, solar and other green “Solartopian” technologies mean atomic energy simply cannot compete without massive subsidies, loan guarantees and government insurance to protect it from catastrophes to come.
This latest “impossible” earthquake has not merely shattered the alleged safeguards of Japan’s reactor fleet. It has blown apart — yet again — any possible argument for building more reactors anywhere on this beleaguered Earth.

(引用終了)

関連するニュースを掲載します。

(引用開始)

【関連】『危険性を過小評価』 燃料棒破損の疑いも

新潟県中越沖地震を受け、柏崎刈羽原発の直下に断層がある可能性を認めた東京電力。広報部は「設計時に今回の規模の地震は想定していなかった」と説明するが、専門家からは「国や東電の見立ては甘い」と指摘する声が上がる。東海地震の想定震源域の真上に立つ浜岡原発(静岡県御前崎市)を運転する中部電力は「安全性は確保されている」としている。
京都大原子炉実験所の今中哲二助教(原子力工学)は「今回の事故で、国の安全審査や(断層は地震の原因にならないとした)東京高裁の判断は、危険性を過小に評価していたことが証明された」と指摘。「耐震設計にできるだけ費用を掛けたくないのが電力会社側の論理。そこに危険性を過小に見積もる余地がある」と話す。
今中助教は「今回はヨウ素が大気中に放出されており、炉心内部にある燃料棒の破損が想定される。配管のひびや、制御系回りのトラブルが発見される恐れもある」と分析する。

東京新聞2007年7月18日 夕刊
U.S. FrontLine News

(引用終了)

http://gijutsu.exblog.jp/tb/5892412
[PR]
by kanconsulting | 2007-07-27 09:11 | 経済状況
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