原発工程表―これ以上悪くせず前へ

2011/04/20
--The Asahi Shimbun, April 19
EDITORIAL: TEPCO must prepare for additional risks in taming Fukushima crisis
原発工程表―これ以上悪くせず前へ

Tokyo Electric Power Co. (TEPCO) has set a specific time frame for its long battle to end the nuclear crisis. The company on April 17 unveiled a road map for stabilizing the dangerous situation at its Fukushima No. 1 nuclear power plant, which was severely damaged by the March 11 earthquake and tsunami.
　「長い闘い」の長さが、数字で見えてきた。福島第一原発の事故収束をめぐって、東京電力が発表した工程表である。

In the first stage of the plan, which will take about three months, measures will be taken to ensure stable and safe cooling of the damaged reactors and spent fuel pools.
　３カ月くらいかけて、事故炉や燃料プールを安定して冷却できるようにする。

In the second stage, steps will be made to bring the reactors to a stable state of cold shutdown in a process expected to require three to six months to complete.
その後３～６カ月ほどで、炉を冷温停止状態に落ち着かせる。

It will take even longer to rebuild the lives of people living in areas around the ravaged nuclear power plant.
TEPCO admitted for the first time that it will take as many as six to nine months just to put the sources of radioactivity under control, which is a prerequisite for Fukushima evacuees to return home and restart their lives.
　原発周辺の人々の生活再建はさらに長い闘いになるが、その前提である放射能源の制圧だけでも６～９カ月かかることを、東電は初めて認めた。

The continuous pouring of water on the reactors and the pools have prevented the No. 1 to No. 4 units at the plant from running out of control.
　福島第一の１～４号機は今、炉やプールに水を注ぎ続けることで小康が保たれている。

If this makeshift measure fails, the risk of a massive release of radioactive materials will grow sharply, forcing the government to reconsider again its policy concerning the evacuation of residents in the surrounding areas.
これが破綻（はたん）したら、放射性物質のさらなる大量放出の恐れが高まり、周辺地域の避難のあり方を再び見直すことにもなろう。

That would place far severer strains on the residents than the already heavy burdens they are bearing now.
　そうなれば、住民が背負う重荷は今の比ではない。

The utility needs to execute its plan for containing the crisis under such circumstances. What is the most important is to prevent the situation from becoming any worse.
　こうしたなかでの収束作戦である。なによりも強く求められているのは、これ以上悪い状態にしない、ということだ。

First and foremost, the company needs to be properly prepared for unpredictable events that may occur.
　まず備えるべきは、不測の出来事だ。

The biggest fear is a possible disruption in external power supply that causes the water injection to stop, which happened after a recent huge aftershock.
とりわけ怖いのは、先日の大きな余震のときのように外部電源が途絶え、注水が止まることである。

TEPCO's blueprint refers to such risks as aftershocks and lightning strikes, indicating that the company is trying to figure out ways to enhance the external power supply system. This should be done swiftly.
　工程表も余震や落雷などのリスクに触れ、外部電源系の補強を考えているようだ。この対策は急務といえよう。

Easing this emergency requires working on reactors and fuel pools that cannot be inspected from up close due to high levels of radiation.
　事故収束に向けた作業は、近づいて中をのぞくことのできない炉やプールを相手にする。

It is certain that the fix-it plan will have to be reviewed after each step is taken.
工程を一歩進めるごとに見直しを迫られるのは必至だ。

The company must not be so focused on carrying out the scheduled plan that it overlooks a big problem.
　期限にばかり気をとられて急ぐあまり、大きな問題点を見逃すことがあってはならない。

The road map raises concerns about whether the number of workers needed to carry through the lengthy process can be secured.
　工程表を見て気にかかるのは長丁場に必要な人力だ。

The plan requires a raft of tough and risky tasks, like sealing the container vessel of the No. 2 reactor and reinforcing the structure supporting the fuel pool for the No. 4 reactor. We wonder how many workers will be needed to perform these jobs.
　２号機格納容器の密閉や、４号機の燃料プール周辺の補強など難しい作業が列挙されているが、それらにどれだけの作業員がかかわるのだろうか。

Workers will face the risk of being exposed to high levels of radiation.
　現場は、放射線を浴びる危険が大きい。

At the entrance to the building housing the No. 1 reactor, for instance, a level of radiation recently detected was so high that working for just an hour at the location would expose the worker to more radiation than the upper limit.
１号機建屋の入り口では、作業員が１時間いるだけで被曝（ひばく）線量限度を超える放射線が測定された。

TEPCO's plan duly acknowledges the risk by pointing out the concern that long-term work at places with high levels of radiation may be required.
工程表にも「放射線レベルの高い場所で、作業が長期化する恐れ」が明記されている。

Workers must be replaced regularly before they are exposed to excessive amounts of radiation.
同じ人にずっと働いてもらうわけにはいかない。

In addition, all of the damaged No. 1 to No. 4 reactor buildings are releasing radiation. That means the measures prescribed must be taken simultaneously at all the four buildings.
　さらに、放射能源を封じなくてはならないのは１～４号機のすべてで、これらの作業を同時に進めなくてはならない。

The manpower that can be provided by TEPCO, the reactor makers and their affiliates may be far from enough to carry out all these tasks.
　東電や原子炉メーカー、関連会社の人たちだけでは、とても追いつかないかもしれない。

Two key challenges in the mission are how to secure a sufficient number of workers, including reinforcements, and how to protect the health of these workers.
　応援を含め、要員をどうやって確保するか。一線で働く人たちの健康をどう守っていくか。

The government is also taking on a heavy responsibility by accepting TEPCO's road map to safety at the crippled nuclear power plant.
　政府も、この工程表を受け入れる以上は責任が重い。