もんじゅ―開発はあきらめる時だ

2011/07/21
--The Asahi Shimbun, July 16
EDITORIAL: Investing billions on new fast-breeder reactor should stop.
もんじゅ―開発はあきらめる時だ

During a regular news conference on July 15, Education, Culture, Sports, Science and Technology Minister Yoshiaki Takaki was asked about the future of the government's Monju prototype fast-breeder reactor in Fukui Prefecture.
　高速増殖原型炉「もんじゅ」（福井県）をめぐる高木義明文部科学相の発言が、波紋を呼んでいる。

He replied, "Rather than discuss it in simplistic terms of scrapping or keeping it, let's just say the answer lies in the government's overall energy policy."
　高木氏は昨日午前、もんじゅについて「廃止とか、単純に継続とかではなくて、全体的なエネルギー政策の中で結論がおのずと出てくる」と述べた。

When his remarks were interpreted to mean that discontinuing the Monju project was an option being considered by the government, a testy Takaki called another news conference later that day.
　それが「開発中止を含め検討」と報じられたのを受け、夕方、改めて記者会見し、

"I never said anything about discontinuing the project," he asserted. "Nobody should be jumping to conclusions."
「中止なんて一言も言っていない」としつつ、「議論に予断は持つわけにはいかない」と語った。

But given the unprecedented gravity of the March meltdowns and Prime Minister Naoto Kan's recent call for a society that relies less on nuclear energy, it is only reasonable to assume that the government intends to radically review the Monju project.
　未曽有の原発事故を起こし、原発依存を下げていく以上、政府がもんじゅのあり方を問い直すのは当然のことだ。

Fast-breeder reactors (FBRs) are "dream reactors" that run and fast-breed their plutonium fuel using plutonium, thereby maintaining a nuclear fuel cycle.
　高速増殖炉（ＦＢＲ）はプルトニウムを燃料にし、運転しながら燃料を「増殖」させる原発だ。
この「夢の原子炉」によってエネルギーを支える構想を、核燃料サイクルとよぶ。

In the past, many countries sought to perfect this nuclear fuel cycle.
　かつては多くの国が核燃料サイクルの実現をめざしたが、

But the United States and other European countries have practically given it up for cost and technical reasons, as well as out of concern for nuclear proliferation issues that might arise from the use of plutonium.
技術的な難しさ、コストの高さ、プルトニウムを扱うことによる核拡散の問題を理由に、欧米はほぼ撤退した。

Japan's Monju project has experienced repeated delays.
　日本の計画も遅れに遅れている。

In the 1970s, the government expected the FBR to be commercialized "between 1995 and 2005."
１９７０年代には「９５～２００５年ごろに実用化する」という計画を描いていたが、

But according to the current nuclear energy policy guideline, the target is "by around 2050."
現在の原子力政策大綱では「５０年ごろまでに実用化」としている。

Soon after its startup, the Monju leaked its sodium coolant in December 1995.
　もんじゅは初発電から間もない９５年１２月に冷却材のナトリウム漏れ事故を起こした後、

The reactor has remained practically idle ever since, but more than 900 billion yen ($11.37 billion) has been sunk into the project so far.
ほとんど稼働していない。すでに９千億円以上を投じ、

And it costs 55 million yen a day just to maintain it.
停止中も１日５５００万円の維持管理費がかかる。

Since Monju is a prototype reactor, it is to be followed by a demonstration reactor and then a commercial reactor.
　しかも、もんじゅは原型炉であり、この次に実証炉、実用炉と続く。

But nothing has been decided as to who will be primarily responsible for the construction of the demonstrator reactor, and the latter will be of a different type from the Monju anyway.
実証炉をだれが主体になってつくるかも未定だ。つくるとしても、もんじゅとは違うタイプになる。

There are no prospects of commercialization.
実用化の見通しは立たない。

In the history of Japan's nuclear development, the Monju symbolized domestic development when all light-water reactors were imports.
　日本の原子力開発の歴史において、普通の原発（軽水炉）が外国から丸ごと輸入されたのに対し、もんじゅは国産開発のシンボルだった。

Sodium, which the Monju uses as a coolant, is difficult to control because it can cause an explosion when it reacts with water.
　しかし、もんじゅで冷却材に使われるナトリウムは水と爆発的な反応をするため、制御が難しい。

It is a highly dangerous substance if an accident does occur.
事故が起きた場合の危険性は極めて高い。

In one of our special editorials that ran on July 13 in the vernacular Asahi Shimbun, we demanded that the government discontinue its nuclear fuel cycle program.
　私たちは１３日付の社説特集「提言　原発ゼロ社会」で、核燃料サイクル計画からの撤退を求めた。

There is little point now in continuing to spend billions of yen on the development of FBRs.
もはや巨額の予算をかけてＦＢＲの開発を進める意味は乏しい。

We believe it is time to abandon the project and decommission the Monju.
ＦＢＲはあきらめ、もんじゅは廃炉にすべきだ。

Once we are through with FBRs, we should radically review the current system of extraction and reprocessing of spent plutonium fuel.
　ＦＢＲ時代が来ない以上、使用済み核燃料からプルトニウムを取り出す再処理事業も、根本的に見直さなければならない。