大型核融合試験施設におけるメガワットミリ波ジャイロトロン発振器周辺の電磁環境調査

将来のエネルギー源として開発が進められている磁場閉じ込め方式の核融合研究では，高温プラズマの生成や制御，プラズマ加熱及び計測のために大電力高周波発振機器が利用されている．本論文では，核融合科学研究所の大型ヘリカル装置で使用されているメガワットミリ波ジャイロトロン発振器(周波数: 77 GHz，最大出力: 1～1.5 MW/2秒)を対象とし，作業従事者の安全管理を目的に，ホーンアンテナを用いて機器周辺での電磁環境を定点調査した．その結果，77 GHz発振器からおよそ30 m離れた場所で観測された漏洩電界の周波数は，77 GHzが最も強く，そこから数GHz離れた両側の周波数領域にも微弱なスプリアススペクトルが確認された．また，同じ場所で，数十秒から数百秒の発振運転に伴う漏洩電界(最大実効値: 数V/m)が観測された．電界の漏洩箇所は，ジャイロトロン発振器を構成する接地電位の電子ビームコレクターと，その他の部位とを電気的に絶縁するために具備された窒化ケイ素製絶縁部と推定された．本研究により，大型核融合試験施設におけるメガワットジャイロトロン発振器周辺のミリ波帯での漏洩電界の実態を初めて明らかにした

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways

Water Vapor Adsorption Properties of Honeycomb-Type Zeolites for Tritium Removal Systems

We have proposed the application of a honeycomb-type adsorbent and catalyst for an advanced tritium removal system. Honeycomb-type materials exhibit a much lower pressure drop than pellet-type materials. In this study, the water vapor adsorption properties of various types of honeycomb adsorbents were evaluated using the breakthrough method at a constant flow rate of 307 cm3/min under various temperature and water vapor partial pressure conditions. The results revealed that the adsorption capacity of water vapor on the honeycomb-type zeolite increased with the water vapor partial pressure and the zeolite content of the honeycomb adsorbents. Furthermore, the honeycomb-type zeolite was found to have a higher adsorption rate than the pellet-type zeolite, and the temperature required for regeneration of the honeycomb-type zeolite was at least 450 K. From the viewpoint of practical use, the honeycomb-type adsorbent that contained 50% zeolite with 200 cells per square inch was considered to have superior adsorption properties and a lower pressure drop among a series of honeycomb-type adsorbents

放射線安全管理年報- 2002年度 -

National Institute for Fusion Science constructed Large Helical Device (LHD) which is the largest magnetic confinement plasma experimental device using super conductive magnet coils sys tem. It took eight years to construct and the first plasma shot had been carried out on March 1998. Since then high temperature plasma and improved plasma confinement experiment have been achieved. This is the report of administrative work at the radiation safety center considering radiation protection for workers at the LHD and related devices, and radiation measurement and monitoring in the site. Major scope is as follows. (1) Radiation measurement and dose monitoring in the radiation controlled area and in the site using particularly developed monitoring system named as Radiation Monitoring System Applicable to Fusion Experiments (RMSAFE). (2) Establishment of education and registration system for radiation workers and accessing control system for the LHD controlled area. As same as the published reports from fiscal year 1999 and 2001, this report is expected to be helpful for the future radiation safety management in the research institute

放射線安全管理年報 （2004年4月1日 - 2006年3月31日）

The National Institute for Fusion Science (NIFS) constructed the Large Helical Device (LHD) which is the largest magnetic confinement plasma experimental device using a super conducting magnet coils system. The first plasma shot was carried out in March 1998 after eight years of construction. Since then high temperature plasmas and improved plasma confinement experiments have been achieved. On 1st April 2004, NIFS became one of the research institutes which constitute National Institutes of Natural Sciences. Since then the regulation system of safety, health and environmental management has been minorly changed. This is a report on administrative work for radiation safety at the LHD and the Compact Helical Device (CHS), and radiation measurement and monitoring on the site from 1st April 2004 to 31st March 2006. Major topics are as follows.(1) Establishment of a radiation safety management system based on the law of occupational safety, health and environment.Radiation dose measurement and monitoring in the radiation controlled area and on the site using a particularly developed monitoring system named Radiation Monitoring System Applicable to Fusion Experiments (RMSAFE).Establishment of an education and registration system for radiation workers, and accessing control system for the LHD controlled area. This report has been annually published from fiscal year 1999. We expect that these reports could be helpful for future radiation safety management in NIFS