ArmsControlWonk: The Sankei Article on Japanese Nukes

The Sankei Article on Japanese Nukes

posted Tuesday December 26, 2006 under nonproliferation, japan by jeffrey

Here is the link to the Japanese language Sankei Shimbun story about a Japanese government study on developing nuclear weapons.

The story doesn’t have the document, but reproduces the “essence” in bullet points:

　一、小型核弾頭試作には最低でも３～５年、２０００億～３０００億円かかる

　一、核原料製造のためウラン濃縮工場拡張は非現実的。軽水炉使用済み燃料再処理をしても不可能

　一、黒鉛減速炉によるプルトニウム抽出が一番の近道

I gather (from a friendly translation) that this boils down to three points:

一 To trial manufacture a miniaturized nuclear warhead, the minimum time required is 3-5 years, and the cost is 200-300 billion yen.

一 To produce fissionable material, the expansion of uranium enrichment facilities is unrealistic; it is also impossible to reprocess spent fuel from light water reactors.

一 The extraction of plutonium from graphite-moderated reactor is the quickest route.

That’s not meant to be a literal translation and Japanese speaking readers are encourage to do better.

More later …

Robot Economist provides an “on the fly” translation in the comments section.

Comment

Here is the full text of the story:

http://www.sankei.co.jp/shakai/wadai/061225/wdi061225000.htm

核弾頭試作に３年以上　費用２０００～３０００億円　政府内部文書

.

　「日本が小型核弾頭を試作するまでには少なくとも３～５年かかる」とする政府の内部文書が２４日明らかになった。「核兵器の国産可能性について」と題した文書によると、日本にはウラン濃縮工場や原発の使用済み核燃料の再処理技術・設備はあるが、技術上の制約から核兵器にただちに転用できないとしている。北朝鮮の核実験を機に日本国内では一部に「非核三原則」の見直しや核武装論が出ているが、日本が仮に核武装する決心をしてもほぼゼロからの開発にならざるをえない、という現実を確認したことになる。

　政府内部文書はことし９月２０日付で作成された。１０月９日の北朝鮮核実験に先立ってひそかに政府機関の専門家が調査し、まとめた。小型核弾頭試作までに３年以上の期間、２０００億～３０００億円の予算と技術者数百人の動員が必要という。これでは仮に日本が核武装宣言しても、ただちに独力で北朝鮮からの「核の脅威」抑止には間に合わない。

　核兵器の材料は、いわゆる広島型原爆材料の高濃縮ウランか長崎型のプルトニウムの２種類。日本原燃の六ケ所村（青森県）原子燃料サイクル施設や日本原子力研究開発機構東海事業所（茨城県）に、ウラン濃縮や原子力発電所の使用済み核燃料再処理工場がある。

　しかし、いずれも軽水炉用で、核兵器級の原料をつくるのには適さない。濃縮工場は純度３％程度の低濃縮ウランを製造するが、そのため稼働している遠心分離機は故障続きで、短期間での大規模化は困難である。

　政府内部文書では、日本が核武装するためには、結局、プルトニウム２３９を効率的に作り出すことができる黒鉛減速炉の建設と減速炉から生じる使用済み核燃料を再処理するラインを設置する必要があると結論づける。さらに小型核弾頭をつくるためには日本にとって未知の技術開発に挑戦しなければならない。（編集委員　田村秀男）

　　　　　　　　　　　　　　　　　　　◇

　【政府文書骨子】

　一、小型核弾頭試作には最低でも３～５年、２０００億～３０００億円かかる

　一、核原料製造のためウラン濃縮工場拡張は非現実的。軽水炉使用済み燃料再処理をしても不可能

　一、黒鉛減速炉によるプルトニウム抽出が一番の近道

　　　　　　　　　　　　　　　　　　　　◇

　■核をめぐる主な動き

　昭和

　３０年　原子力三法公布

　３７年　国産１号炉が臨界

　４４年　動燃事業団、遠心分離法でウラン濃縮実験に成功

　５１年　日本政府、核拡散防止条約（ＮＰＴ）批准

　５２年　米原子力政策グループ、再処理凍結を大統領に勧告

　５４年　米スリーマイルアイランド２号機で事故

　６１年　旧ソ連のチェルノブイリ原発で事故が発生

　平成

　　４年　日本原燃産業、ウラン濃縮工場操業開始

　　７年　朝鮮半島エネルギー開発機構（ＫＥＤＯ）設立

　　８年　包括的核実験禁止条約に署名

　１０年　インドとパキスタンが相次ぎ核実験

　１３年　米中枢同時テロ

　１５年　北朝鮮がＮＰＴ即時脱退を宣言

　１７年　国連総会が核テロリズム防止に関する国際条約を採択

　１８年　１０月９日、北朝鮮が地下核実験

　（電気事業連合会のサイトなどから）

(2006/12/25 02:38)

— Jeffrey Lewis · Dec 26, 07:29 PM ·
Jeffrey – Here is my rough translation of the article:

“According to a government report released on the 24th of December, it would take 3-5 years to build a prototype of a miniaturized nuclear warhead. The report “The Domestic Potential for Nuclear Weapons” says that although Japan has the uranium enrichment and nuclear fuel reprocessing facilities needed, technical limitations would make it difficult to divert them to weapons production. A discussion of revising the first part of Japan’s “Three Non-Nuclear Principles” has emerged since the North Korean nuclear test the report confirmed the reality that hypothetical Japanese nuclear weapons would be starting from ‘square one.’

The report was proposed on the 20th of September. It went forward after the North Korean nuclear test on the 9th of October. It would take at least 3 years and 200-300 billion yen to mobilize the hundreds of technical needed to build a miniature nuclear warhead prototype. This would be good enough for a hypothetical nuclear-armed Japan to check North Korean nuclear threats alone.

The ingredients of nuclear weapons would include uranium for the type of bomb used over Hiroshima or plutonium for the type of bomb used over Nagasaki. The Japanese Atomic Energy Agency (Ibaraki Prefecture) and the Nuclear Fuel Cycle Facility (Aomori Prefecture) can do both uranium enrichment and nuclear fuel reprocessing.

However, using their light water reactors will not yield weapons-grade plutonium. Enrichment facilities only manufacture LEU enriched to 3% and frequently experience mechanical problems, so expanding enrichment would be difficult.

According to the government report, Japan would have to construct a graphite-moderated breeder reactor and expand its reprocessing facilities to produce enough Pu 239 needed for a nuclear arsenal. It would also be difficult for Japan to miniaturize nuclear warheads because there are many gaps in the technical knowledge required for development.”

I apologize for the roughness of the translation. Japanese is a language prone to run-on sentences that don’t always translate well.

Jeffrey’s translation of the three bullets that follow the body of the report are pretty accurate. After that is a timeline of the evolution of Japan’s nuclear policy from the end of WWII to today. I can translate it if the readers want.

— Robot Economist · Dec 27, 12:02 AM ·
Reading through the article, it seems the Japanese Government has based their calculations on the assumption that immediately usable fissile material is not readily available, and they will have to expand reprocess facilities. However, surely, utilizing Japan’s already significant stockpile of reactor grade plutonium could speed up the production time. Reactor grade plutonium is not optimal but it can be used to produce an explosive device. Furthermore, they mention a miniaturized warhead, which would suggest its placement on a missile. Miniaturizing a nuclear weapon, as they state, requires a fair degree of technical sophistication, so maybe a cruder device – like Little Boy – could be produced far more quickly. Just a thought.

Anway, Selig Harrison and Ryukichi Imai edited a book about this topic in 1996, and from memory (and my memory aint so great these days) the “within a year” time period is quoted there as well.

— Nippon Otaku · Dec 27, 04:54 PM ·
Not to be a pain in the neck about the provided translation…but no.
A somewhat more correct translation is:

It became public knowledge on December 24 that an internal government document exists stating, “It will take at least 3 to 5 years until Japan can go into trial production of a miniaturized warhead.” According to the document, entitled, “As regards the possibility of national production of atomic weapons” while Japan does have uranium enrichment facilities and the technology and equipment for reprocessing spent nuclear fuel, there are technical barriers that prevent the immediate conversion of these [capabilities]. Although a debate has emerged in one segment of Japanese society on the occasion of North Korea’s nuclear test regarding the need for nuclear armaments or a review of the “Three Non Nuclear Principles”, it has been confirmed that even if a decision were made to proceed with arming Japan with nuclear weapons, Japan will be basically starting from zero.

The internal government document was completed on September 20. Well before the October 9 nuclear test by North Korea, specialists within various branches of the government conducted a survey and compiled [the report]. It says that to produce a prototype miniaturized warhead will take more than 3 years, a budget of 200 billion to 300 billion yen and several hundred technicians.

As for the materials to be made into nuclear weapons, they will be either of two types, namely, HEU used in the Hiroshima atomic bomb or Nagasaki-type plutonium. There are nuclear fuel cycle processing facilities at Japan’s nuclear fuels manufacturing center of Rokkasho (in Aomori Prefecture) and uranium enrichment and a nuclear power station spent fuel reprocessing plant at the Tokai civilian nuclear research group facility (in Ibaraki Prefecture).

However, neither is appropriate for production the nuclear materials out of the fuel designed for used light water reactors [bad original sentence – MTC]. The uranium enrichment facility can produce 3% LEU. Operating the centrifuges in order to produce [HEU] would lead to constant breakdowns. It would be essentially impossible to scale up over the short term.

The internal government document concludes that in order for Japan to arm itself with nuclear weapons, it would, in the end, have to construct a graphite moderated nuclear reactor for the efficient production of Pu 239. It would also be necessary to establish a reprocessing line for this reactor. Furthermore, Japan will have to push itself to aquire the technological knowledge required for the manufacture of miniaturized warheads.
(Editor: Tamura Hideo)

— MTC · Dec 28, 09:34 AM ·
MTC: You are not being a pain … in fact, rather the opposite. I am really happy that the ACW community can provide a translation, complete with healthy debates about any difficult passages.

So, thank you to both Robot Economist and MTC for a providing a model of the sort of things I’d like to see in the comment section—people posting articles, translations , and (oh, glorious day) calculations.

— Jeffrey Lewis · Dec 28, 12:05 PM ·
A translation from the USG:

Internal Government Document Concludes That It Would Take Japan Over Three Years To Make A Prototype Model Nuclear Warhead At Cost Of 200-300 Billion Yen

Sankei Shimbun (in Japanese, 061225, no link available)

This newspaper has learned from an internal Japanese government document acquired on Dec. 24 that "it would take three to five years at least for Japan to build a prototype-model miniaturized nuclear warhead." According to the document, titled, "On the possibility of a domestically-built nuclear weapon," although Japan has a plant that can enrich uranium and the technology and facilities to reprocess spent nuclear fuel used in power plants, it cannot directly switch to producing nuclear weapons due to the technological constraints.

Although North Korea's nuclear weapon test set off calls in some circles in Japan for a review of the three no-nuclear weapons principles and a debate over whether Japan should possess its own nuclear arms, the report recognized the reality that even if Japan should have the intention of producing its own nuclear weapons, it would undoubtedly have to start from scratch in developing such.

The internal government document was secretly drafted on Sept. 20, 2006, prior to North Korea's nuclear test on Oct. 9. An expert at a government agency researched and compiled the report. The expert concluded that it would require over three years until a prototype miniaturized nuclear warhead could be produced, and that it would cost between 200 billion and 300 billion yen. So even if Japan declared that it intended to possess nuclear arms, it could not immediately produce on its own a deterrence to the nuclear threat posed by North Korea.

There are two types of materials used in making nuclear weapons: enriched uranium, which went into making the atom bomb that was dropped on Hiroshima, and plutonium, which was used to make the bomb dropped on Nagasaki. Japan has a nuclear fuel recycling facility at Rokkasho Village in Aomori Prefecture and a factory in Ibaraki Prefecture for reprocessing spent nuclear fuel and uranium enrichment. But such facilities are all for light-water reactor use and inappropriate for making material for use in nuclear weapons.

Seems to be missing some things, especially at the end.
— Jeffrey Lewis · Dec 28, 02:27 PM ·
To give credit where credit is due, I see that Robot Economist’s translation of the second sentence paragraph 4 is correct while mine is mistaken.

While hurriedly copying and pasting, I managed to lose a goodly part of the second paragraph, which is important, as the correct translation says the opposite of what the Robot Economist translation has it saying:

“The internal government document was completed on September 20. Well before the October 9 nuclear test by North Korea, specialists within various branches of the government quietly conducted a survey and compiled [the report]. It says that to produce a prototype miniaturized warhead will take more than 3 years, a budget of 200 billion to 300 billion. If Japan were to declare itself a nuclear weapons state in the interim, Japan could not immediately by itself check the ‘nuclear threat’ posed by North Korea.”

— MTC · Dec 28, 05:24 PM ·
That’s a damn good translation MTC. I haven’t translated Japanese news articles for a few years, so my skills are a bit rusty. Its good to have an excuse to flex them though.

Speaking of translations, I’ve started posting translations of Japanese news items dealing with nonproliferation and nuclear weapons on my new blogspot site.

— Robot Economist · Dec 28, 08:12 PM ·

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