レベル７ 「最悪」の更新を防げ

(Mainichi Japan) April 13, 2011
Japan must prevent another Level 7 nuclear plant crisis by all means
社説：レベル７　「最悪」の更新を防げ

The Chernobyl disaster in 1986, which was rated Level 7 on the International Nuclear and Radiological Event Scale (INES), is still regarded as the world's worst nuclear power plant accident in history. Level 7 crises are accidents that lead to "major releases of radioactive materials."
　世界の原発史上最悪の事故は８６年に旧ソ連で起きたチェルノブイリ原発事故と考えられてきた。国際評価尺度（ＩＮＥＳ）では、「放射性物質の重大な外部放出」を伴うレベル７と評価されている。

Just recently, the government has raised the level of the crisis at the Fukushima No. 1 Nuclear Power Plant that was hit hard by a massive tsunami generated by the March 11 Great East Japan Earthquake to Level 7 on the INES.
　政府は、東京電力福島第１原発で続いている事故もまた、レベル７に相当すると認めた。

The decision will not cause any change in the work underway to place the crippled nuclear plant under control. Now, there is no choice but to take all possible measures to cool down the cores of the affected reactors.
　これによって事故収束に向けた作業が変わるわけではない。今は安定した冷却に向け、あらゆる対策をとっていくしか選択肢はない。

Still, questions remain as to why the crisis level was raised at this time. It would be a problem if it reflects the government's underestimation of the seriousness of the crisis and reluctance to fully release information on the accident.
　しかし、なぜ今ごろになって評価を引き上げたのか、疑問は残る。事故に対する認識の甘さや、情報公開への及び腰な態度を反映してのことなら、問題だ。

The government raised the crisis level of the Fukushima nuclear accident from 4 to 5 on March 18. By that time, explosions and fires had occurred near the affected reactors one after another. It was obvious that a considerable amount of radioactive substances had been leaking from the reactors, judging from the levels of radiation around the plant.
　政府は福島原発の事故を３月１８日にレベル４から５に引き上げている。この時すでに、原子炉周辺では次々と爆発や火災が起きていた。周囲の放射線レベルを見ても、かなりの量の放射性物質が放出されているのは明らかだった。

Nevertheless, an estimation of the total amount of radiation leaked from the plant, based on which the crisis level was rated 7, had not been released until recently. The government explained that it took a long time to increase the accuracy of the data. However, it will lose the public's confidence if it had been aware that the accident should be rated Level 7 but delayed the announcement by saying it was still analyzing figures.
　ところが、レベル７の判断材料となる放出総量の試算はなかなか公開されなかった。精度を上げるのに時間がかかったというのが政府の説明だが、レベル７を認識しつつ、毎日「試算中」と答えるにとどまったとすれば信頼を損なう。

The government was also slow in releasing the cumulative radiation levels, based on which evacuation plans are worked out. The data, which is indispensable in ensuring the safety of residents near the plant, must be transparent and released promptly.
　計画避難の判断基準となる積算線量の公開にも、もたつきが見られた。積算線量は住民の安全を守るために不可欠なデータで、情報公開に不透明さや遅れがあってはならない。

The government has also emphasized the differences between the Fukushima plant accident and the Chernobyl crisis. It is true that the Fukushima accident is different from Chernobyl in which massive levels of radiation were released in a short period of time and that some people died of acute radiation exposure. The amount of radiation that has leaked from the Fukushima plant is estimated at one-tenth of that which leaked from the Chernobyl plant.
　政府は、チェルノブイリと福島原発の事故の違いも強調している。確かに、放射性物質が一時に大量放出され、被ばくによる急性放射線障害で死者が出たチェルノブイリとは状況が異なる。これまでのところ放出量も１０分の１と見積もられている。

At the same time, the Fukushima crisis is unprecedented in that four of its reactors simultaneously became out of control. Slow but constant radiation leaks from the plant have confused local residents. No one can tell how long the crisis will continue or whether it will develop into a more serious catastrophe.
　一方で、福島原発では４基が一度に制御不能に陥るという前代未聞の事態が起きた。だらだら続く放出は、周辺住民を翻弄（ほんろう）している。それがいつまで続くのか、もっと深刻な事態が起きるのか。予測はつかない。

Therefore, Japan is required by the international community to reconfirm the seriousness of the Fukushima nuclear plant crisis and respond to it rather than compare the degree of the accident with that of the Chernobyl crisis. Tokyo Electric Power Co. (TEPCO) that operates the crippled Fukushima No. 1 Nuclear Power Plant as well as the government should reflect on their overly optimistic thinking that an accident like the Chernobyl crisis would never happen in Japan, which led to the serious situation at the Fukushima plant.
　そう考えると、事故の程度を比較するより、改めて福島原発の深刻さを受け止め、対処することが国際的にも求められる。日本ではチェルノブイリのような事故は起こり得ないと考えた東電や政府の甘さが過酷な事故につながったことも再確認すべきだ。

Powerful aftershocks following the March 11 earthquake have been occurring in not only Fukushima Prefecture but also many other areas. The crisis has illustrated the vulnerability of nuclear power plants -- they tend to lose external electric power sources necessary to cool down the reactor cores if hit by powerful temblors. It is also obvious that some of the nuclear power plants across the country face risks of being paralyzed by powerful quakes and ensuing tsunami.
　福島だけでなく各地で大きな余震が続いている。地震で外部電源が失われやすいという原発施設の弱点も浮き彫りになった。全国の原発の中に巨大地震や津波のリスクを抱えているものがあることも明らかだ。

While working to place the plant under control, the government and power suppliers must inspect nuclear power plants across the country and take measures to prevent major earthquakes and tsunami from causing major crises at these facilities. Another Level 7 nuclear power plant catastrophe must be prevented by all means.
　福島の事態収拾とは別に点検と対策を急ぐべきだ。レベル７をもうひとつ抱えるような事態は、決して引き起こしてはならない。

毎日新聞　2011年4月13日　東京朝刊