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核燃料サイクル

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詳細 2016年4月24日 18:41更新

核燃料サイクル、または核燃料リサイクル。
この実態を知っている人は日本人の何割ほどだろうか?

サイクルの中でも最も重要とされる再処理と高速増殖炉はいずれも核兵器材料の生産工程です。
それを日本政府は平和利用と位置付けてゴリ押ししています。

私の判断では技術的、経済的、外交的、戦略的、全てにおいて、また倫理的にも正当性がありません。
エネルギー自給率の確保にも実はほとんど寄与しません。
世界各国が次々に撤退している事業に何故に固執しているんでしょうか?

私の判断では核武装オプションを残すためにしか見えません。
恐らくそうでしょう。それ以外には推進に固執する理由が見当たりません。

技術的にも達成の見込みの薄いものを多大なる予算をかけて推進しています。
事故続きです。益々予算は膨らみます。それでも達成は無理でしょう。

間違いなく厄介な瞬殺レベルの核廃棄物が増えていきます。
隔離する方法も場所も全く決まっていません。イメージだけはできてますけどね。
サイクルができないと必然的に原子力発電が止まるらしい。廃棄物の問題で。
だったら止まっていいんじゃない?
原子力発電を停止して電力供給が止まることはありません。

一方、地球温暖化問題で原子力は二酸化炭素を出さないので有効だと言う説もありますが、全くの詭弁です。温暖化対策は別に考えるべきです。瞬殺核廃棄物の処分ができるのならばいいでしょうが、世界中の何処の国もできていません。この国土に制約のある日本でできる可能性は非常に厳しい状況です。二酸化炭素を貯留する方が有効かつ安全な方法です。それも技術的に達成はしていませんが。とにかく別の問題です。

一部抜粋ですが後ろに翻訳も乗せます。みんなでよーく考えよう。
日本の核兵器材料の生産=核燃料サイクルを
http://www.nci.org/02NCI/04/mm-jpu-paper.htm

JAPAN, NUCLEAR WEAPONS, AND REACTOR-GRADE PLUTONIUM
presented to seminar at Nuclear Control Institute March 27, 2002

ISSUES

Under what circumstances would Japan seek to acquire nuclear weapons?

What political/legal route to weapons might it take?; in particular, what are the safeguards implications of a decision to withdraw from the NPT and utilize transferred nuclear technology?

What technical options would Japan have to produce fissile material for weapons; in particular, could it use its stocks of reactor-grade plutonium (RGPu) to make reliable, high-yield weapons, and is this option more attractive than others ?

What are the implications of the above for US nonproliferation policy?

POLITICS

The official policy of the post World War II Japanese government has always been to disavow any intention to acquire nuclear weapons. The stated rationale is that Japan, as the only victim of nuclear attack, is especially sensitive to the immense human suffering caused by their use, and that it is protected from nuclear threats by other countries by the US nuclear umbrella. Moreover, Article 9 of the Japanese Constitution renounces war as a sovereign right of the nation, and prohibits the maintenance of military forces as well as other war potential.

Nevertheless, the intensive and protracted debate in Japan over whether and on what terms it should sign and ratify the Nuclear Non-Proliferation Treaty (NPT) - it signed in 1970 and ratified in 1977 - reflected the fact that some Japanese leaders wanted to keep a nuclear weapons option open. Indeed, in 1967 the Prime Minister E. Sato commissioned a secret study to assess the costs and benefits of nuclearization from the technical, economic, strategic, political, and diplomatic perspectives.

More recently, speculation about possible Japanese nuclearization has increased due to several factors including: (1) China's assertive political and military posture towards Japan; (2) North Korea's nuclear and missile development program; and (3) Japan's strong commitment to a closed nuclear fuel cycle and its growing surplus of reactor-grade plutonium.

On the other hand, a nuclear-armed Japan would not be in China's security interests, and the US-Japan alliance remains firm, especially after its upgrade in 1996. While the US has encouraged Japan to help maintain the US nuclear deterrent in the Pacific, it has not encouraged Japan to acquire nuclear weapons of its own. Such encouragement would violate US obligations under Article 1 of the NPT, and would deal a severe, if not fatal blow to the global nonproliferation regime.

Thus, it would take a geopolitical sea change" for Japan to overcome its "nuclear allergy". However, if Japan decides to go nuclear, what options would it have, politically and technically?

SAFEGUARDS & THE NPT

Politically, Japan could legally withdraw from the NPT by giving three months advance notice, in accordance with Article X, par. 1, instead of violating the treaty by acquiring nuclear weapons while still a non-weapons state party to it. But the agreements for nuclear cooperation that Japan has with its major nuclear suppliers, the US, France, and Canada, all provide for "back-up" safeguards on transferred materials and technology in the event that Japan withdraws from the NPT.

In particular, the Agreement for Cooperation Between Japan and the US Concerning Peaceful Uses of Nuclear Energy (November 4, 1987) requires both back-up safeguards on and the right to require the return of "any material, nuclear material, equipment or components transferred [by the US to Japan or vice versa] pursuant to this agreement or any special fissionable material produced through the use of such items if either party terminates or materially violates a safeguards agreement with the Agency [i.e., the IAEA]." (Article 9, par. 2 and Article 12, par. 1).

Thus, Japan would have to violate these agreements in order to use such materials and technology for nuclear weapons. Moreover, if Japan left the NPT the nuclear suppliers would be obligated both by domestic legislation and by the Nuclear Supplier's Group (NSG) guidelines to terminate further transfers of materials and technology, e.g., the natural uranium that would be needed as feed for production reactors and centrifuge plants. [This underscores the utility of both uranium from seawater and breeder reactors as routes to both nuclear energy security and nuclear weapons.]

Whether these constraints would count for much if Japan decided that it needed nuclear weapons is open to question. Thus, it's worth considering its

TECHNICAL WEAPONS OPTIONS

Besides the direct use of reactor-grade plutonium (RGPu), Japan has several other options to obtain plutonium and weapons-grade uranium (WGU) [Ref. Harrison, pp. 18, 19]:

1. Producing weapons-grade plutonium (WGPu) in power reactors by shutting them down more frequently for refueling, thus reducing the fuel burnup, and increasing the Pu-239 content of the contained plutonium;

2. Upgrading RGPu to WGPu, or producing WGU from natural or low-enriched uranium (LEU) by a laser separation process;

3. Using its commercial centrifuge plant to produce WGU instead of LEU;

4. Separating the plutonium produced in the natural uranium blankets of its Monju experimental breeder reactor which has a higher Pu-239 content than WGPu;

5. Producing WGPu in a production reactor; and one option not considered by Harrison:

6. Using the stocks of WGPU and WGU - several hundred kg of each - in its fast critical assemblies.

Arguably, one or more of these options, e.g., (3) or (6), might be more attractive than using RGPu, depending on how many weapons would be required in what time frame, and the perceived need for testing. However, in the following we consider whether Japan could build reliable, high-yield weapons using RGPu. According to the latest unclassified US DOE guidance on the subject of using RGPu in weapons:

The degree to which the obstacles to the use of RGPu can be overcome depends on the sophistication of the state or group attempting to produce a nuclear weapon. At the lowest level of sophistication, a potential proliferating state or sub-national group using designs and technologies no more sophisticated than those used in first generation nuclear weapons could build a nuclear weapon from RGPu that would give an assured, reliable yield of one or a few kilotons, and a probable yield much greater than that. At the other end of the spectrum, advanced nuclear weapons states such as the US and Russia, using modern designs, could produce weapons from RGPu having reliable explosive yields, weight, and other characteristics generally comparable to those of weapons made from WGPu...Proliferating states using designs of intermediate sophistication could produce weapons with assured yields substantially higher than the kiloton-range possible with a simple, first generation nuclear device.

So the question is: where is Japan on the weapons sophistication spectrum?; also how much can one say/has been said/is worth saying on an unclassified basis with regard to how the problems involved in using RGPu can be minimized using designs more advanced than the "Fat Boy" implosion bomb ? [Fuchs' sketch]

In my judgment, Japan is at least at the intermediate point, and most probably at the high end of the weapon's capability spectrum. By this I do not mean to imply that Japan has a clandestine nuclear weapons program under way - I have no knowledge of such an effort - rather that the competence of their scientists in related applications indicates that they could make advanced weapons using RGPu if the political decision is made to go ahead. Although design considerations relevant to the use of RGPu in weapons are still classified, much has already been said on the subject in the open literature, e.g.,

1. After the discovery of the high rate of spontaneous fission of Pu-240 by E. Segre in Spring 1944, the scientists at Los Alamos realized that only the implosion design would work for plutonium, and then only if high-purity plutonium was used and/or it was in the form of a shell rather than a solid pit. While "Fat Boy" did use high-purity plutonium, " the hollow implosion device, as conceived then, could not have been built with the wartime technology of high explosive and fissile material", and a solid pit configuration, the "Christy gadget", was chosen instead. (Ref. L. Hoddeson et al., p. 446, footnote .# 9).

2. In 1956, British scientists realized that the plutonium primaries in their thermonuclear designs were vulnerable to predetonation from external neutron sources. "They came to a startling conclusion - that there was a high risk that British nuclear weapons could be disabled by an intense flash of radiation from a nearby nuclear detonation, that is, from a defensive enemy warhead launched for this purpose. Fission weapons with plutonium cores were particularly vulnerable because of plutonium's susceptibility to pre-detonation... To make an immune warhead required knowledge of certain techniques imperfectly understood at Aldermaston at the time. One was boosting, the addition of thermonuclear material to a fission bomb in order to enhance the efficiency of the fission process and so increase the yield." (Ref: L. Arnold, Britain and the H-Bomb, Palgrave, New York, 2001, p. 177.)

Without going into details, a study of Japanese work in such areas as high-explosive technology, inertial fusion, and production and handling of hydrogen isotopes leads me to the conclusion that they are capable of solving the problems involved in using RGPu in weapons, specifically predetonation. In sum, I would agree with the following assessment by Richard Garwin:

As for the more sophisticated designer, it is my judgment that not only the five nuclear weapons states but also the nuclear weapon establishments of India, Pakistan, and Israel are capable of converting reactor grade plutonium into nuclear weapons that have similar yield to those made with weapons grade plutonium; they would not suffer at all from the high neutron generation rate of reactor grade plutonium

And add Japan and other advanced non-nuclear weapons states such as Germany to his list.


CONCLUSION

The question then is not whether Japan could build reliable, high yield, low weight weapons using RGPu if it decided to go nuclear, but would it, considering its other possible options. In my judgment, the nuclear weapon states, particularly the US, should strive to keep Japan as far as possible from the need to seriously consider this issue. This will require leadership by example in devaluing the role of nuclear weapons, while working to lessen regional tensions, in the Middle East, South and North Asia. At the same time, safeguards and physical security on all existing weapons-useable materials, including RGPu, need to be upgraded, and their stocks decreased.


日本、核兵器と原子炉級のプルトニウム

問題

どんな状況の下で、日本は核兵器を得ようとしますか?
それは、どんな政治的な/法律ルート?
日本には、武器の為の材料を生産するのに、どんな技術的なオプションがありますか?

政治

第二次世界大戦後、日本政府の公式方針は、核武装についてはどんな意向でも常に否定することになっていました。その正当性は、日本が、核攻撃の唯一の犠牲者として、特に核兵器の使用に起因する巨大な人間の苦しみに敏感であるということで、そして、それが米国核の傘によって他の国による核の脅威から保護されているということです。さらに、日本の憲法の第9条は、国の主権的権利として戦争を捨てて、他の戦力と同様に軍隊の整備を禁止しています。
それでも、もう一度日本での集中的で長引いた議論‖(NPT) - 1970年に署名されて、1977年に批准されるそれ - この時間差は一部の日本のリーダーが核兵器オプションを開いていておきたかったという事実を反映しました。
事実、1967年に、E.サトウ首相は、秘密裏に技術的、経済的、戦略的、政治的、外交の展望から核武装の費用と利益を評価するよう委嘱しました。
近年は日本の核武装への有り得る推測はいくつかの要因から可能性をましました。
1.中国の姿勢
2.北朝鮮の核及びミサイル開発
3.日本の強い核燃料サイクルへの固執と原子炉級プルトニウムの増え続ける余剰在庫です。
一方、日米同盟は堅固ままです。米国が日本を太平洋で米国核抑止力を維持するのを援助させる間、それは日本を独自の核兵器を得させませんでした。

日本が核武装する決断するならば、政治的に、そして、技術的に、それにはどんなオプションがありますか?

安全保障とNPT

3ヶ月の予告期間をもってNPTから脱退できる。できますがそれは様々な国際協調の断絶を伴います。
日本は核武装の為にそれらの材料と技術を使用するためには協定を破る必要があります。
それが重要であるか否かに関わらず日本が核武装を必要とするか否かには考慮する価値があります。

技術オプション

原子炉級のプルトニウム(RGPu)の直接の使用の他に、日本にはプルトニウムと兵器級ウラン(WGU)を得るために、いくつかの他のオプションがあります。

プルトニウムのPu-239内容を増やすためによりしばしば炉をシャットダウンすることによって動力炉で兵器級プルトニウム(WGPu)を生産すること。

RGPuをWGPuにアップグレードするか、レーザー分離プロセスまでにWGUを天然であるか低濃縮ウラン(LEU)から作り出すこと。

LEUの代わりにWGUを生じるためにその商業的な遠心分離機プラントを使うこと

もんじゅは兵器級プルトニウム生産炉。

既に余剰しているWGPUとWGUを使用する。

RGPuの使用に対する障害が克服されることができる程度は、核兵器を生産しようとしている国またはグループの洗練度に依存します。

日本は少なくとも、武器の能力範囲は高レベルです。
これによって、私は日本が秘密の核兵器プログラムを進行中にすることを意味するつもりでありません - 私には、そのような努力についての知識がありません - むしろ、関連したアプリケーションの彼らの科学者の能力が彼らが先進の武器に政治決断ならばRGPuを使うことを作ることができることを示すことは、進ませられます。

結論

核兵器国(特に米国)は、深刻にこの問題を考慮する必要からできるだけ遠く日本を保つよう努めなければなりません。


以上だいぶ要約だけどそれでも長いけど、
要約すると日本はその気になればすぐに核兵器を持てちゃうから、その気にならないように、そんな必要がないように核兵器国(特に米国)は努めなければならない。

やめさせた方が早いじゃん?きっと出来やしないし、金ばっかり掛かってどうしようもないよ。

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