核燃料取り出し 政府が前面に出て廃炉目指せ

The Yomiuri Shimbun November 21, 2013
Govt must take lead in Fukushima nuclear reactor decommissioning
核燃料取り出し　政府が前面に出て廃炉目指せ（11月20日付・読売社説）

Decommissioning work at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant, which is expected to take 30 to 40 years, is finally under way.
　今後、３０～４０年間にわたって続く廃炉作業の入り口に、ようやく立ったということだろう。

Work has begun to remove nuclear fuel from the plant’s No. 4 reactor, bringing the decommissioning work into a new stage of the timetable drawn up by the government and TEPCO.
　東京電力福島第一原子力発電所の４号機で、核燃料の取り出しが始まった。政府、東電が策定した廃炉工程表の新たな段階である。

There are many unknown aspects to deal with, and work to remove nuclear fuel is difficult, as it will continue to take place in an environment with high radiation levels. TEPCO must give top priority to ensuring safety and tackle this task with utmost seriousness.
　未知の領域が多く、強い放射線の中での困難な作業が続く。東電は安全確保を最優先に、緊張感を持って取り組まねばならない。

The No. 4 reactor was offline for a regular inspection at the time of the outbreak of the nuclear crisis in March 2011. Unlike the Nos. 1 to 3 reactors, a core meltdown did not occur at the No. 4 reactor, as nuclear fuel was kept with unused fuel in a storage pool inside the reactor building.
　４号機は事故当時、定期検査中だった。核燃料は建屋内のプールに未使用の核燃料とともに保管されていたため、１～３号機のような炉心溶融は起きなかった。

However, hydrogen believed to have come from the neighboring No. 3 reactor via an exhaust system exploded, blowing off the upper portion of the No. 4 reactor building.
　だが、隣の３号機から排気系統を伝って流れ込んだとみられる水素が爆発し、建屋が壊れた。

Inside the storage pool, there are 1,331 spent nuclear fuel assemblies and 202 unused fuel assemblies. TEPCO plans to remove all of them by the end of next year.
　プール内に残った使用済み核燃料は１３３１体、未使用燃料は２０２体に上る。東電は来年末までに、それらをすべて取り出す。

Although reinforcement work has been carried out at the No. 4 reactor, leaving nuclear fuel in the seriously damaged building brings risks of radiation leaks. Removing nuclear fuel is thus an indispensable part of reactor decommissioning. Nuclear fuel assemblies are to be pulled out of the storage pool one by one with a crane, placed in a shipping container and moved to a shared pool.
　４号機には補強工事を施したとはいえ、損傷が大きい建屋に核燃料を置いておけば、放射能漏れのリスクを伴う。燃料取り出しは廃炉に向けた不可欠な作業だ。核燃料を１体ずつつり上げて輸送容器に入れ、共用プールに移す。

During the nuclear fuel removal process, meticulous attention must be given to debris remaining inside the No. 4 reactor’s storage pool. It is necessary to prevent such debris from damaging nuclear fuel assemblies when the assemblies are pulled out of the storage pool.
　取り出し作業で細心の注意が求められるのは、４号機のプール内に残るがれきだ。核燃料をつり上げる際に接触するなどして、傷つけないようにする必要がある。

Thorough NRA checks needed

The Nuclear Regulation Authority will oversee the nuclear fuel removal work under a special system. It is important that the NRA thoroughly check whether its schedule is realistic and ensure that potential sources of trouble have not been overlooked.
　原子力規制委員会は特別体制で作業を監督する。スケジュールに無理はないか。トラブルの種が見過ごされていないか。しっかりとチェックすることが大切だ。

As for the Nos. 1 to 3 reactors, damaged areas have yet to be identified and the melted fuel situation is unknown. The amount of water contaminated with radioactive substances apparently leaking from damaged areas has continued to increase.
　１～３号機については損傷部が特定されておらず、溶けた燃料の状況も分からない。損傷部から漏れる汚染水は増え続けている。

We urge TEPCO to apply the expertise it gains during the nuclear fuel removal work at the No. 4 reactor to recovering melted fuel and other materials at the Nos. 1 to 3 reactors.
　４号機の核燃料取り出し作業で得られるノウハウを、１～３号機での溶融した燃料などの取り出しにも役立ててもらいたい。

The development of advanced robots that can be used for monitoring the situation inside reactors, as well as technology to repair damaged sections, must be taken full advantage of.
　炉内の状況把握に役立つ高度なロボットや、損傷部分の補修技術の開発も進めねばならない。

One major challenge is to secure a sustainable workforce for decommissioning the reactors.
　大きな課題は、廃炉作業を担う要員の持続的な確保である。

The decommissioning work is arduous, since it requires workers to wear a full face mask and protective suit. It remains difficult even now to organize the 2,000 to 3,000 workers believed to be needed for this work.
　全面マスクと防護服を着けて進める作業は過酷だ。２０００～３０００人が必要とされる要員の手配は、現在でも容易でない。

As the decommissioning work proceeds, workers will face increased levels of exposure to radiation, and some restrictions may be needed to limit access to the sites by experienced technicians.
　廃炉工程が進めば、放射線の被曝(ひばく)量がさらに増え、現場への立ち入りを制限せざるを得ないベテラン技術者も出るだろう。

More than ¥2 trillion is said to be necessary for reactor decommissioning work and measures to deal with contaminated water. The government must move steadily forward with this long-term decommissioning work, by taking the lead in developing the needed technology, securing a sustainable workforce, and providing financial assistance.
　廃炉・汚染水対策には２兆円以上が必要とされる。政府が前面に出て技術開発や要員確保、資金支援に取り組み、長丁場の廃炉作業を確実に進めることが肝要だ。

(From The Yomiuri Shimbun, Nov. 20, 2013)
（2013年11月20日02時21分  読売新聞）