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東京電力福島第一原子力発電所の事故に伴い放出された放射性物質の地表への沈着状況等を踏まえ、原子力機構は、事故直後から国内外の関係機関と協力しつつ環境回復に率先して取り組んできた。これらの取組みは避難住民の早期帰還や住民の安全・安心の確保に向けて、環境中での放射性セシウムの挙動の理解を深め、それを踏まえた沈着状況の将来予測や帰還住民の被ばく線量を評価するための鍵となる役割を担っている。これまでの環境回復の取組みに基づき得られた知見と技術について解説するとともに、今後取り組むべき課題を整理する。, This review provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Dai-ichi accident as input for developing a technical knowledge base including remediation technologies which is translated into actions that enable the rapid return of evacuees. It is reflecting JAEA's key role in the research associated with both remediation of contaminated areas and the natural processes influencing contamination migration in non-remediated areas, working together with a number of Japanese and international organisations and research institutes. This review also provides a perspective on the future actions required to remediate areas outside the Fukushima Dai-ichi site.

平成23年3月11日に福島第一原子力発電所の事故が発生し環境中へ大量の放射性物質が放出された。これらは自然の駆動力によって移動、生活圏に到達し健康等に影響を及ぼす可能性が懸念されており、事故状況の把握や影響評価や対策のため調査研究が多く行われている。原子力機構は、取得データと関係省庁等が取得した公開データを収集・整理し「環境モニタリングデータベース」として公開している。また、これらデータ及び既存または開発した計算コードを用いて「統合解析支援環境」の中で事故後の状況再現や将来予測のため解析を行っている。また、これら知見は他研究機関の成果とあわせ「環境回復知識ベース」として一般の方々が理解できるよう公開ウェブサイトにQ\&A方式で公開している。これら三要素を包含し「福島の環境回復に係る包括的評価システム」と呼ぶ。これらは本来は相互に関連し一システムとして機能すべきところ、現状では独立して機能している。また、十分にオープンで理解しやすい形で外部に発信されているとは言えない。そこで、データや成果に対しより理解を深めることができ求める情報に容易にたどり着けるよう、当システム全体及び各要素の整備を行っていく。, The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q\&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.

Radial energy deposition distribution, the distribution of DNA strand breaks and their yields were simulated by Monte Carlo track structure simulation for C and Ne ions with the same linear energy transfer (LET) around 450 keV/mm. The radial DNA damage distribution shows different pattern for C and Ne ions. Double strand break (DSB) are mostly formed in the central area, while the single strand break (SSB) tends to spread to the surrounding area. It is also shown that the production efficiency of the SSB and DSB depends on the radial distance. This result shows reasonable agreement with the recently obtained experimental observation, which indicates that different types of DNA damage shows different distribution patterns around C and Ne ion paths in cell nuclei.

The frequency of single strand breaks(SSBs) occurring on both strands of the pBR322 plasmid DNA region flanked by a pair of primers used for polymerase chain reaction(PCR) amplifications was determined after irradiation with 137Cs gamma rays. We verified that real time PCR is suitable for the detection and quantitative analysis of SSBs caused by gamma irradiation. The utility of this approach was also supported by the comparison of the practical experimental data with the Monte Carlo simulation. The potential application of this PCR method for the detection of genomic DNA damage was also confirmed.

A letter to the editor of the Journal of Environmental Radioactivity on the article: E. Gasser, A. Nachab, A. Nourreddine, Ch. Roy, and A. Sellam, `Update of 40K and 226Ra and 232Th series $��$-to-dose conversion factors for soil', J. Environ. Radioactiv. 138, 68-71 (2014), DOI: 10.1016/j.jenvrad.2014.08.002., Author accepted manuscript, Journal of Environmental Radioactivity (2015), 9th Jan 2015, 2 pages, 1 figure

In this paper, we give infinite dimensional stochastic processes generated by functions of the Lévy Laplacian. Moreover we introduce an operator to connect the Lévy Laplacian with the Number operator and also give a relationship between a (Co)-semigroup generated by the Lévy Laplacian and an infinite dimensional Ornstein-Uhlenbeck process., This is the proceedings of the 2nd Japanese-German Symposium on Infinite Dimensional Harmonic Analysis held from September 20th to September 24th 1999 at the Department of Mathematics of Kyoto University., この論文集は, 1999年9月20日から9月24日の日程で京都大学理学研究科数学教室において開催された第2回日独セミナー「無限次元調和解祈」の成果をもとに編集されたものである., 編集 : ハーバート・ハイヤー, 平井 武, 尾畑 信明, Editors: Herbert Heyer, Takeshi Hirai, Nobuaki Obata #en

6th Workshop on Internal Dosimetry of Radionuclides

The doses of patients on X-ray CT imaging are higher than other general X-ray diagnoses. On the view point of radiation protection, the optimizations of X-ray CT imaging are very important. However, it is not easy to estimate patients\' doses by direct measurements using dosemeters. We have calculated the patients\' doses by the method of Monte-Carlo simulations. The mathematical phantom used in the simulations was a voxel phantom of a Japanese male, which have been developed in JAERI. It was based on the pictures of X-ray CT scanning for the whole body, and constructed of about 6.63 million voxels. The simulation code was EGS4, and the fortran compiler was g77 in a Pentium IV PC Linux machine. The geometry of the voxel phantom was included in the EGS4 user code. The material data of the voxels were soft tissue, lungs and bone data of ORNL. As the X-ray spectra with filters for each tube voltages, Birch\'s data were referred in the user code. For X-ray CT imaging conditions of calculations, some typical X-ray CT diagnoses were selected. As photon irradiation parameters, the exposure area, slice number, slice width and X-ray tube voltages were set. The center axis and X-ray tube focus positions were determined based on a real X-ray CT machine geometry. The energy depositions of organs were calculated, and patients\' doses were estimated. The ratios of entrance surface dose and each organ doses can be obtained and used for the estimation of the doses. They are useful as indicators for the consideration of optimization on X-ray CT imaging in practice., 11th International Congress of the International Radiation Protection Association

International symposium on innovative technology for radiation risk study 2003