Development of elemental components in NDA systems for certifying radioactive wastes with the clearance level

Tsutsumi, Masahiro; Oishi, Tetsuya*; Yamasoto, Kotaro; Yoshida, Makoto

JAERI-Research 2004-021, 43 Pages, 2004/12

JAERI-Research-2004-021.pdf:8.55MB

We have designed and developed a measurement system to certify radioactive wastes below the clearance level. By advancing non-destructive -ray assay technology, it aims at quantitative determination of radionuclides contained in 200 litter drum/container wastes. Unlike the waste from a nuclear power plant, you have to assume that the waste originating from radioisotope usage and nuclear research laboratory have a variety of contents and a complex mixture of radionuclides, and furthermore the uniformity of activity concentration is unknown. To cope with the problems, we have developed the -ray measuring instruments (units) with effective improvement of capability against each problem. They are (1) germanium spectrometry unit for enhanced peak identification, (2) positioning detection unit for positioning of interactions and (3)high-efficiency detection unit for separation of low-energy component. This report summarizes the direction of the clearance level measuring system and the three developed measuring units with their performances.

Characterization of cryogenically cooled silicon crystals, for the double-crystal monochromator on BL11XU at SPring-8

Tozawa, Kazukiyo*; Kiriyama, Koji*; Mitsui, Takaya; Shiwaku, Hideaki; Harami, Taikan

JAERI-Tech 2004-041, 27 Pages, 2004/03

JAERI-Tech-2004-041.pdf:5.11MB

Liquid-N-cooled Si crystals replaced water-cooled diamond crystals for the double-crystal monochromator on BL11XU at SPring-8. To use the whole energy from 6 keV to 70 keV, we developed the system of dual symmetric Si geometry, Si(111)/Si(311), which can be switched by a horizontal translation (X) stage perpendicular to the beam axis. The off-line experiment was performed to estimate the degree of the crystal strain, which may arise from the way of assembling in the crystal holder. With MoK, rocking curves from the crystals were measured for the second crystal of the double-crystal diffractometer of parallel setting. Each of the observed full-width at half maximum (FWHM) was almost constant and identical to the calculated value wherever X-rays hit on the crystal surface. By the use of synchrotron radiation from the undulator the crystals were tested and then the characterization was performed. The observed intensities and rocking curves resulted in that each crystal was good for BL11XU and that the performance of X-ray reflection was improved.

Protection and control of accelerator microwave sources using a high power IGBT switch

Loring, M.*; Moriyama, Shinichi; Kasugai, Atsushi; Terakado, Masayuki; Nakayama, Nobuyoshi*; Iiyama, Toshimitsu*

Proceedings of 26th International Power Modulator Symposium and 2004 High Voltage Workshop, p.271 - 273, 2004/00

The control and protection of high power electron tubes has been a serious problem throughout the history of power electronics. This paper briefly covers the history of approaches used to meet these needs and discusses a modern solution which has uses in fusion research, accelerator, and commercial applications. The paper describes the design, development and performance history of a family of high voltage IGBT switches used for the control and protection of megawatt level gyrotrons in the JT60U facility. The switch systems described have been in use for several years. The demonstrated long, {over 20,000 system hours. (over 2,000,000 device hours)} life shows the inherent reliability of a well designed, properly operated HV DC IGBT switch system. This device has many other uses in modern high power electronic systems. In the application described, the switch carries current of the order of 100 amperes DC at 100 kV DC. The development was a joint effort of the Japan Atomic Energy Research Institute and the switch manufacturer, IDX Corporation.

Helicity switching of circularly polarized undulator radiation by local orbit bumps

Hara, Toru*; Shirasawa, Katsutoshi*; Takeuchi, Masao*; Seike, Takamitsu*; Saito, Yuji; Muro, Takayuki*; Kitamura, Hideo*

Nuclear Instruments and Methods in Physics Research A, 498(1-3), p.496 - 502, 2003/02

https://doi.org/10.1016/S0168-9002(02)02145-9

no abstracts in English

Development of d.c.power supply for gyrotron with energy recovery system

Tsuneoka, Masaki; Fujita, Hideo*; Sakamoto, Keishi; Kasugai, Atsushi; Imai, Tsuyoshi; Nagashima, Takashi; ; ; ; ; et al.

Fusion Engineering and Design, 36(4), p.461 - 469, 1997/00

https://doi.org/10.1016/S0920-3796(97)00024-0

no abstracts in English

New design and development for an ultrahigh-voltage short pulse switch power supply

Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki*

no journal, , 

We will present presentation on the design of super high voltage short pulse switch using SiC - MOSFET operating at high withstand voltage, low loss, high frequency and high temperature, aiming at sophistication of pulse electromagnet power supply for 3 GeV synchrotron accelerator. This switch has a radially symmetric type of a module switch which does not cause level fluctuation due to the timing jitter by equalizing the circuit length independently of the number of semiconductor switches. By connecting these modules hierarchically in series, it is possible to cope with high voltage and current output of 40kV/2kA or more. The design and preliminary test results are presented here.