著者
山崎 正勝
出版者
日本科学史学会
雑誌
科学史研究 (ISSN:21887535)
巻号頁・発行日
vol.60, no.297, pp.1-18, 2020 (Released:2021-10-06)

Hidehiko Tamaki, who engaged the uranium criticality calculations at the Riken during the Second World War, died on February 10, 2013, and the related materials at Tamakiʼs house were preserved at the Riken Archives in Wako City, Saitama Prefecture. The author takes up a handwritten manuscript by Tamaki that begins with "§1. Necessity of chain reaction and factors that hinder its realization," and examines it using reproduction calculation. It is shown that Tamaki had obtained the mixture ratio of uranium and water as moderator so that it let the amount of uranium used minimum. It was also pointed out that there was a discrepancy in the formula of the output energy evaluated under the condition of constant pressure. After presenting a method to avoid it, Rikenʼs reactor system was reexamined, and it is shown that there was a lack of the concept of controlling chain reactions including consideration of delayed neutrons and neutron absorbers such as the control rods of todayʼs nuclear reactors, so it was difficult to use it for power.
著者
山崎 正勝
出版者
日本科学史学会
雑誌
科学史研究 (ISSN:21887535)
巻号頁・発行日
vol.48, no.249, pp.11-21, 2009 (Released:2021-08-04)

In the early years of the Cold War, both the United States and the Soviet Union used their nuclear power technology as a diplomatic tool for expanding their political influence on respective friendly nations. On December 8, 1953, the United States initiated a new international nuclear program with President Dwight D. Eisenhower's "Atoms for Peace Address" before the General Assembly of the United Nations. This program regarded Japan as one of the most promising countries that could introduce nuclear power plants since it consumed a huge amount of energy while being short of natural resources. This paper studies the historical process of the atomic energy agreement between Japan and the US in 1955 using declassified documents in both countries. It shows that in spite of various proposals of the introduction of nuclear power plants into Japan including that of Congressman Sydney Yates, the final agreement was only for research reactors because American authorities felt that such proposals might mean an admission of US guilt in atomic bombing. It also argues that the agreement was one of steps toward the hegemony of bureaucrats and politicians in Japanese nuclear policy that made the leadership of scientists, especially those of the Science Council of Japan, decline.
著者
山崎 正勝 奥田 謙造
出版者
日本科学史学会
雑誌
科学史研究 (ISSN:21887535)
巻号頁・発行日
vol.43, no.230, pp.83-93, 2004 (Released:2021-08-12)
被引用文献数
1

In March 1954 a Japanese fishing vessel, Daigo Fukuryu Mam (Lucky Dragon No.5), suffered from radiation exposure from an American nuclear test at Bikini in the South Pacific. After this incident there appeared both in the US and in Japan a nuclear policy debate that the nuclear energy for peaceful purposes in general, and nuclear reactors in particular should be introduced into Japan in order to counter the communists' propaganda against American nuclear tests and anti-American movements in Japan. The Operation Coordinate Board of the US National Security Council adopted this policy very soon after the Bikini Incident. This was followed a wide range of strategic programs for Japan. Hidetoshi Shibata, then an executive of the Nippon Television Network Corporation, started his press campaign in January 1955 in the newspaper Yomiuri Shimbun together with its owner Matsutaro Shoriki, later the first president of the Japanese Atomic Energy Commission, for promoting nuclear energy for peaceful purposes. Shibata and Shoriki apparently were working together to fight against anti-nuke movements and anti-American activities in Japan. In May they invited John J. Hopkins, President of General Dynamics Corporation, Nobel laureate Ernest Lawrence from the University of California at Berkley, and Lawrence Hafstad, director of the division of reactor development of the American Atomic Energy Commission. Their talks in Tokyo were reported to have impressed many Japanese. This paper shows that Yomiuri Shimbun group's activities were in fact supported by the US government, and were carried out within the framework of the US foreign policy.
著者
山崎 正勝
出版者
日本科学史学会
雑誌
科学史研究 (ISSN:21887535)
巻号頁・発行日
vol.40, no.218, pp.87-96, 2001 (Released:2021-08-17)

Soon after the dropping of the Hiroshima bomb, Yoshio Nishina, an experimental physicist who was in charge of the Army's development of nuclear weapons at Riken, the Institute of Physical and Chemical Research, could understand that it was an atomic bomb because its energy release given in Truman's statement coincided with the one that his colleague Hidehiko Tamaki estimated a few years ago. This suggests that they knew of the magnitude of nuclear explosions. Uraniumu bakudan (uranium bomb), Japanese physicists' bomb at the time, is, however, known to be a kind of nuclear reactor out of control. The "bomb" of this kind is not very powerful because it is based on a slow-neutron reaction. This paper challenges to reproduce Japanese physicists' calculations at the time, and shows that they thought that they could explode their uraniumu bakudan, a slow- reactor bomb, with a quite high efficiency. This led them to expect that the energy release from their bomb would be of 20 K ton TNT equivalence that accidentally coincided with the energy release of the Hiroshima bomb.
著者
山崎 正勝
出版者
日本科学史学会
雑誌
科学史研究 (ISSN:21887535)
巻号頁・発行日
vol.25, no.160, pp.225-234, 1986 (Released:2021-09-22)

The first idea of atomic bomb proposed by E. Fermi and, especially, L. Szilard, who was the real writer of Einstein's letter to President F D Roosevelt in 1939, was shown to be based on a fast neutron chain reaction in normal uranium which was later proved to be inert for fast neutrons At that time such an idea was also proposed independently by L. Peierls in Britain, but he soon abandoned it because of its great critical mass estimated theoretically by himself. The large scale enrichment of uranium was at first pursuited to produce a thermal nuclear chain reaction (the nuclear reactor) effectively. This stream was thus independent of that for the construction of the bomb at the early stage Those two streams above were, however, joined together in 1940 by O. Frisch and Peierls in their memorandum on a super bomb, which first showed the technological principle of atomic bomb based on the fast neutron chain reaction in pure uranium 235 In contrast to these two streams in the U.S. were kept divisitive by compartmentalization of information adopted by V.Bush, the chairman of NDRC. The idea of the Frisch-Peierls memorandum is studied in detail in comparison with the MAUD reports, the British official reports, completed in the summer of 1941. It is shown that the influence of the British research on the atomic bomb was the most important factor for the full start of the development of the bomb in the U.S. in the autumn of 1941. The problem on independence between NAS report of November 6,1941 and the MAUD reports is discussed.
著者
安藤 晴夫 柏木 宣久 二宮 勝幸 小倉 久子 山崎 正夫
出版者
日本海洋学会
雑誌
海の研究 (ISSN:09168362)
巻号頁・発行日
vol.12, no.4, pp.407-413, 2003-07-05 (Released:2008-04-14)
参考文献数
7
被引用文献数
15 20

1970年代から月1回実施されている公共用水域の水質モニタリングデータを用いて,東京湾全域の表・底層水温の長期的な変動傾向を月別に検討した。その結果,水温の長期変動傾向は季節により異なり,概ね5月~8月には下降傾向,10月~3月には上昇傾向が認められた。また,地域的にも傾向が異なり,外洋水の湾内への流人経路と考えられる湾南西部の海谷に沿う地点で特にこうした上昇・下降傾向が顕著であった。外洋水の水温は湾内の海水に比べて夏季には低く,冬季には高いことから,湾内への外洋水流入量が長期的には増加傾向にあると仮定すると,こうした傾向をよく説明できる。
著者
山崎 正樹 櫻井 澄 根上 彰生
出版者
公益社団法人 日本都市計画学会
雑誌
都市計画論文集 (ISSN:09160647)
巻号頁・発行日
vol.48, no.3, pp.297-302, 2013-10-25 (Released:2013-10-25)
参考文献数
5
被引用文献数
2 2

本研究は、施行から約10年が経過し、一定の事例が蓄積されてきた都市再生特別地区におけるソフト分野の公共貢献に着目し、東京都を対象とした提案・実施状況の実態の調査及び課題と改善方策の考察を行った。2012年8月現在における、東京都で提案されたソフト貢献を整理した結果、全24事例のうち22事例、貢献内容としては64件が提案され、種別としては「都市や街の魅力の向上」に寄与するものが約4割を占めることが明らかになった。次に提案されたソフト貢献の実現状況の把握のために、稼働済事例を対象に開発事業者・運営事業者及び東京都へのヒアリング調査を行った結果、東京都と開発事業間で提案内容実施にかかる協定が締結されており、全ての事例でソフト貢献が実現されていることが確認できた。運営形態は事業者が自ら運営事業を行う「自主型」が約6割、運営委託を行う「誘致型」約4割であり、概ねの事例で建築物稼働日より1年前には運営主体が決定している。しかし、素案上の「イメージ」を実現できない事例や、都決時以降に追加されたソフト貢献が評価されない事例、ソフト貢献の有効的な利活用が事業者の努力次第となること等の課題もみられた。
著者
山崎 正俊 宇根崎 博信
出版者
Atomic Energy Society of Japan
雑誌
日本原子力学会和文論文誌 (ISSN:13472879)
巻号頁・発行日
vol.9, no.3, pp.243-251, 2010 (Released:2012-02-08)
参考文献数
8
被引用文献数
1 1

For the sake of more efficient operation of nuclear power plants and to reduce the number of spent nuclear fuel assemblies, increasing uranium enrichment is one of the rational options. However, current uranium enrichment for the whole fuel cycle infrastructure is limited to no greater than 5 wt% from the view point of criticality safety. In this review, three main topics are discussed: 1) the necessity of increasing the uranium enrichment above 5 wt%; 2) current status and challenges to go over 5 wt% enrichment; and 3) proposal of the “Erbia Credit Super High Burnup Fuel” as a measure to break the “5 wt% enrichment barrier.” The third topic is further elaborated on by discussing the introduction scenarios before concluding with a mention of the necessity of a best-mix analysis for this concept in the fuel cycle supply chain.
著者
山崎 正志
出版者
三輪書店
巻号頁・発行日
pp.1085-1092, 2019-12-25

はじめに 腰椎椎間板ヘルニアに対するコンドリアーゼ(ヘルニコア®)を用いた椎間板内注入療法(以下,コンドリアーゼ療法)が本邦で認可され,新しい椎間板内酵素注入療法として,その普及が期待されている.コンドリアーゼ療法を紹介する際に,しばしば話題に上るのが,1980年代に北米を中心として世界的に盛んに施行されていたキモパパイン椎間板内注入療法(以下,キモパパイン療法)である3).キモパパイン療法に対する評価のほとんどは,「アナフィラキシーショック,横断性脊髄炎や重度の腰痛などの重篤な副作用の発現により,施行されなくなった」という内容のものである.しかしながら,これらの評価は,適切な科学的解析のもとに下された結論といえるのであろうか? 筆者が渉猟し得た限りでは,キモパパイン療法を科学的に完全に否定している資料は見当たらない. キモパパイン療法が北米で全盛を迎えていた1980年代の初めに,これを本邦に導入することにひときわ情熱を傾けていたのが,当時千葉大学整形外科教授の井上駿一先生であった.井上先生の強力なリーダーシップのもと,千葉大学を中心にキモパパイン療法の基礎的臨床的研究が本邦においても盛んに行われた5,6,11,12).筆者も当時,大学院生として,その研究に加わっていた15〜17).1987年に井上駿一先生が研究半ばで急逝されたため,本邦におけるキモパパイン研究は,ややその勢いを失いかけた感はあった.しかしながら,その後も研究は継続され,Phase Ⅲ臨床試験までが行われた1).その結果は,十分に満足すべきものであり,重篤な合併症はなかったと記憶している.しかしながら,本邦でのキモパパイン療法の臨床使用が認可されることはなく,その後,コンドリアーゼ療法が登場するまでの約30年間は,キモパパイン療法が話題に上がることはほとんどなくなった. 今回,本邦におけるキモパパイン療法の基礎的臨床的研究を史的に考察した.確かに,キモパパイン療法そのものは歴史的な存在であろう.しかし,今後の発展が期待されるコンドリアーゼ療法の臨床的な効果を議論するうえで,キモパパイン療法との比較は,有益な情報をもたらすと考える.その意味で,本稿では,キモパパインとコンドリアーゼとの比較を加味して執筆を行った.