Fifty-four nuclear reactors are situated in coastal areas of Japan. Many experts have repeatedly pointed out how difficult it is to ensure the safety of nuclear power plants in this earthquake-prone country.
Some scientists had predicted that radiation could leak from a nuclear power plant if it was damaged by a powerful quake and ensuing tsunami. One of them, Kobe University professor emeritus Katsuhiko Ishibashi, called such a potential accident an "earthquake-triggered nuclear power plant disaster."
However, electric power suppliers as well as the government had dismissed such warnings as a "minority opinion." The consequences of this attitude are the serious crisis at the crippled Fukushima No. 1 Nuclear Power Plant operated by Tokyo Electric Power Co. (TEPCO).
The distortion of the earth's crust caused by the powerful quake has had a huge impact on various areas of Japan. No optimism can be justified for future seismic activity in the Japanese archipelago.
The government has no choice but to seriously consider whether quake-prone Japan can coexist with nuclear power stations, take prompt countermeasures and drastically change its nuclear energy policy.
The biggest problem with nuclear power plants is their lack of measures against tsunami. Measures to protect nuclear plants from tsunami are incorporated in the government's guidelines for the quake-resistance of nuclear power plants that were revised in 2006, but priority has not been given to anti-tsunami measures. Moreover, power suppliers have been slow to re-examine their nuclear plants in accordance with the amended guidelines. TEPCO has not even completed its re-examination.
On the other hand, some electric power companies strengthened measures to protect their nuclear plants from tsunami following the Chuetsu Offshore Earthquake in Niigata Prefecture in 2007. One of them is the Tokai No. 2 Nuclear Power Plant in central Japan.
It is not permissible to conclude that the crisis at the Fukushima plant was caused by an unexpected massive tsunami.
TEPCO's responses to the crisis are highly questionable. TEPCO was unprepared for a situation in which all external power sources were lost and it became impossible to cool down nuclear reactors for a long time. This is despite the fact that following the 1979 crisis at the Three Mile Island nuclear power station in the United States, countermeasures against serious nuclear power plant accidents were worked out in Japan to cope with the possibility of more catastrophic nuclear plant disasters.
Initial responses to a nuclear power station accident are extremely crucial. Nevertheless, TEPCO was slow in introducing power-supply vehicles to the crippled plant, ventilating the reactors and pouring sea water into the reactors to cool them down. This shows that TEPCO was unprepared to implement serious accident countermeasures.
Power suppliers should put priority on securing electric power sources at their nuclear power stations in case of emergency. Guidelines for measures to protect nuclear plants from tsunami and their quake-resistance need to be promptly reviewed.
The government has also come under mounting pressure to review its regulations on nuclear power plants and the system to supervise them.
We have repeatedly pointed out that it is contradictory that the Nuclear and Industrial Safety Agency that regulates and supervises nuclear power plants comes under the umbrella of the Economy, Trade and Industry Ministry that is promoting nuclear power generation. The government's responses to the accident have illustrated this contradiction. Furthermore, the accident has called into question the raison d'etre of the Cabinet Office's Nuclear Safety Commission (NSC). The government should reorganize these bodies into a completely independent regulatory organization.
But the implementation of these measures alone is not enough.
Following the crisis at the Fukushima plant, NSC Chairman Haruki Madarame remarked, "Nuclear power stations can't be designed without discarding the potential for some problems, but the accident shows the way the potential problems were disregarded was wrong."
His remarks have raised questions as to whether a catastrophic accident can be prevented if problems are conveniently disregarded and whether it is enough to strengthen safety regulations, improve equipment and work out measures to respond to any emergency situation.
Both the government and power suppliers had emphasized for many years that nuclear power plants are safe because they are protected by multiple safety devices. However, the latest crisis has illustrated the fragileness of the multiple protective devices.
In other words, the accident has demonstrated that complete safety can not be achieved even if far more protective devices are installed at nuclear plants, and that serious accident countermeasures, implemented following the Three Mile Island disaster, have been unable to quickly bring the potential for nuclear disaster under control.
There are arguments that aircraft and trains pose similar safety risks. However, a catastrophic accident involving a nuclear power plant has a far more serious and far-reaching impact over a far lengthier period. The risks posed by the coexistence of unpredictable major earthquakes and nuclear power plants should not be tolerated.
Considering such risks, extreme prudence should be exercised in considering whether to resume the operations of other nuclear power plants in quake-hit areas, such as the Onagawa plant in Miyagi Prefecture. It will be almost impossible to build new nuclear power stations from now on.
Based on these realities, we recommend that Japan take the opportunity of the Fukushima disaster to launch efforts to decrease its reliance on nuclear power plants from a long-term perspective. It is unrealistic to simultaneously dismantle all the existing nuclear power plants. Rather, Japan should gradually decrease its reliance on nuclear power generation by prioritizing the dismantling of nuclear power plants that are considered more vulnerable to disasters.
Top priority should be placed on decommissioning the Hamaoka Nuclear Power Plant in Shizuoka Prefecture that sits just above the probable focus of a Tokai quake that is believed certain to occur sooner or later.
In the latest disaster, the focus of several quakes simultaneously moved and caused a massive quake. The possibility cannot be ruled out that the focus of Tokai and Tonankai and Nankai earthquakes in central and western Japan will simultaneously move, causing a huge quake and tsunami.
Aging nuclear power plants are particularly vulnerable to earthquakes because the most advanced technology for ensuring safety of such power stations is not incorporated in them and the most advanced knowledge of seismology is not taken into account in their design.
Japan has relied on nuclear power generation for 30 percent of the total electric power consumed across the country. Many people think that nuclear power plants should be maintained as a stable source of electric power. Some have expressed concern that the Japanese economy could not survive without such power generators.
Still, we should understand that the "quake-triggered nuclear power plant disaster" occurred as a result of putting priority on the economy over safety. It is hoped that we will come up with ways to live affluent lives without relying on nuclear power plants even though the pros and cons of maintaining such plants should be decided by the whole nation.
The promotion of recyclable energy sources -- to which close attention is being paid as measures to prevent global warming -- and the achievement of a low-energy consumption society will be a key to breaking away from Japan's dependence on nuclear power. Now is the time for Japan to pursue electric power sources that are suitable for such an earthquake-prone country and adopt lifestyles that match the supply of electricity.
Click here for the original Japanese story
(Mainichi Japan) April 16, 2011
社説：震災後 地震国の原発 政策の大転換を図れ
いつ、どこで、どれほど大きな地震や津波が起きても不思議はない。しかも、それを予測するすべを私たちは持たない。
日本列島の現実を改めて思い知らされる１カ月だった。
予測不能な大地震だけでも日本が抱える大きなリスクである。その海岸沿いに５４基の原発が建ち並ぶ。地震と原発の共存がいかにむずかしいか。警告は何度も発せられてきた。
石橋克彦・神戸大名誉教授のように「原発震災」という言葉で惨事を予見してきた科学者もいる。しかし、電力会社も政府も「少数派」として退けてきた。その帰結が今、私たちが直面する東京電力福島第１原発の深刻な事故である。
◇「想定外」許されぬ
大地震がもたらした地殻のゆがみは各地に影響を与えている。今後の地震活動は、予断を許さない。
地震国日本は原発と共存できるのか。真摯（しんし）に検証した上で、早急に打つべき手を打ちながら、原発政策の大転換を図るしかない。
まず、誰もが問題だと思うのは津波対策の不備だ。０６年に改定された原発耐震指針に盛り込まれているが、扱いは非常に軽い。新指針に基づく再点検も後回しにされ、東電は点検を終えていない。
一方で、東海第２原発のように新潟県中越沖地震の後に津波対策を一部強化していたところもある。「想定外の津波」という言葉で事故を総括することは許されない。
事故対応にも疑問は多い。７９年の米スリーマイル島原発事故をきっかけに、設計の想定を超える事態への対応として「過酷事故対策」が日本でも用意された。
ところが、今回のようにすべての電源が失われ、原子炉が長期間にわたって冷却不能に陥った場合の具体的備えが東電にはなかった。
事故対応には初動が何より大事だ。にもかかわらず、電源車の用意や、原子炉の換気、海水注入などに手間取った。過酷事故対策を運用する準備があったとは思えない。
当面の課題は、全国の原発で電源確保を確実にすることだ。津波対策や耐震強化の見直しも急がねばならない。
国の規制や監視体制も改革を迫られている。監督官庁である原子力安全・保安院が原発推進の立場にある経済産業省に属する矛盾はこれまでも指摘してきた。今回の対応にもその矛盾を感じる。原子力安全委の存在意義も問われている。完全に独立した規制機関を再構築すべきだ。
ただし、こうした「手当て」を施して良しとするわけにはいかない。
事故発生後、原子力安全委の班目春樹委員長は「割り切らなければ原発は設計できないが、割り切り方が正しくなかった」と述べた。安全委員長の発言として納得できないが、それに加えて疑問が浮かぶ。
割り切り方を間違えなければ大事故は起きないのか。安全規制を厳しくし、設備や緊急時の対応策を整えれば、事足りるのかという点だ。
これまで、電力会社も政府も、原発は安全装置を何重にも重ねた「多重防護」に守られ、安全だと強調してきた。しかし、今回の事故で多重防護のもろさがわかった。どこまで安全装置を重ねても絶対の安全はなく、過酷事故対策も事故を収拾できなかったというのが現実だ。
◇依存度下げる決意を
リスクがあるのは飛行機や列車も同じだという議論もあるだろう。しかし、原発は大事故の影響があまりに大きく、長期に及ぶ。地震国であるという日本の特性も無視できない。予測不能な地震と原発の掛け算のようなリスクを、このまま許容できるとは思えない。
大震災の影響を考えれば、女川原発など被災した原発の再開も非常に慎重に考えざるをえない。今後の原発の新設は事実上不可能だろう。
こうした現実を踏まえ、大災害を転機に、長期的な視点で原発からの脱却を進めたい。既存の原発を一度に廃止することは現実的ではないが、危険度に応じて閉鎖の優先順位をつけ、依存度を減らしていきたい。
第一に考えるべきは浜岡原発だ。近い将来、必ず起きると考えられる東海地震の震源域の真上に建っている。今回、複数の震源が連動して巨大地震を起こした。東海・東南海・南海が連動して巨大地震・大津波を起こす恐れは見過ごせない。
老朽化した原発も危険度は高い。原発の安全性の知識も地震の知識も進展している。古い原発にはその知識を反映しにくい。
日本は電力の３割を原発に依存してきた。安定した電源として擁護論は強い。原発なくして日本の経済が成り立たないのではないかという懸念もある。
しかし、経済と安全をてんびんにかけた結果としての原発震災を直視したい。最終的には国民の判断ではあるが、原子力による電源に頼らなくても、豊かに暮らすための知恵を絞りたい。
そのためには、温暖化対策で注目された再生可能エネルギーの促進や低エネルギー社会の実現がひとつの鍵となるはずだ。地震国日本に適した電源と、それに基づく暮らし方を、今こそ探っていく時だ。
英訳
毎日新聞 2011年4月15日 0時07分
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