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Journal Articles

Development of human resource capacity building assistance for nuclear security

Noro, Naoko; Nakamura, Yo; Hirai, Mizuki; Kobayashi, Naoki; Kawata, Norio; Naoi, Yosuke

Modern Environmental Science and Engineering, 3(5), p.309 - 313, 2017/05

The paper introduces methodologies of ISCN for nuclear security training curricula development. The paper focuses on the contribution of ISCN for curriculum development of IAEA transport security training course which ISCN hosted in 2015.

Journal Articles

Development of human resource capacity building assistance for nuclear security

Noro, Naoko; Nakamura, Yo; Hirai, Mizuki; Kobayashi, Naoki; Kawata, Norio; Naoi, Yosuke

Proceedings of 18th International Symposium on the Packaging and Transport of Radioactive Materials (PATRAM 2016) (DVD-ROM), 7 Pages, 2016/09

The paper describes the methdologies ISCN has adopted to develop its training curricula on nuclear security. ISCN has been working closely with the international partners to build its own capacity, especially with the Sandia National Laboratories of the United States. The paper then focuses on the joint course development between IAEA and ISCN on the International Training Course on Transport Security which ISCN hosted in 2015.

Journal Articles

Review of five investigation committees' reports on the Fukushima Dai-ichi Nuclear Power Plant severe accident; Focusing on accident progression and causes

Watanabe, Norio; Yonomoto, Taisuke; Tamaki, Hitoshi; Nakamura, Takehiko; Maruyama, Yu

Journal of Nuclear Science and Technology, 52(1), p.41 - 56, 2015/01

 Times Cited Count:7 Percentile:60.95(Nuclear Science & Technology)

On March 11, 2011, the Tohoku District-off the Pacific Ocean Earthquake and the subsequent tsunami resulted in the severe core damage at TEPCO's Fukushima Dai-ichi Nuclear Power Plant Units 1-3, involving hydrogen explosions at Units 1, 3, and 4 and the large release of radioactive materials to the environment. Four independent committees were established by the Japanese government, the Diet of Japan, the Rebuild Japan Initiative Foundation, and TEPCO to investigate the accident and published their respective reports. Also, the Nuclear and Industrial Safety Agency carried out an analysis of accident causes to obtain the lessons learned from the accident and made its report public. This article reviews the reports and clarifies the differences in their positions, from the technological point of view, focusing on the accident progression and causes. Moreover, the undiscussed issues are identified to provide insights useful for the near-term regulatory activities including accident investigation by the Nuclear Regulation Authority.

Journal Articles

Evaluating methods to improve safeguards training courses of ISCN

Okumura, Yukiko; Nakamura, Yo; Kawata, Norio

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2015/01

Although questionnaires were used to receive feedbacks from participants at the end of each training course, Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) of Japan Atomic Energy Agency (JAEA) did not establish a structured evaluation method. To this end, ISCN has started to study on methods to accurately evaluate the courses since April and started to introduce the evaluation method on trial, according to the Donald Kirkpatrick's Four-Level Training Evaluation Model, so as to better develop and conduct more effective courses. This paper will focus on how ISCN has modified the Kirkpatrick's Four-level to adapt to its safeguards training courses. This will then be followed by two particular cases of how the evaluation method functioned for the Additional Protocol training courses held in Malaysia in 2014, and the feedbacks received to improve future training courses.

Journal Articles

Analysis on effects of transverse electric field in an injector cavity of compact-ERL at KEK

Hwang, J.-G.*; Kim, E.-S.*; Miyajima, Tsukasa*; Honda, Yosuke*; Harada, Kentaro*; Shimada, Miho*; Takai, Ryota*; Kume, Tatsuya*; Nagahashi, Shinya*; Obina, Takashi*; et al.

Nuclear Instruments and Methods in Physics Research A, 753, p.97 - 104, 2014/07

 Times Cited Count:7 Percentile:50.1(Instruments & Instrumentation)

Journal Articles

Review of five investigation committees' reports on the Fukushima Dai-ichi Nuclear Power Plant severe accident; Focusing on accident progression and causes

Watanabe, Norio; Yonomoto, Taisuke; Tamaki, Hitoshi; Nakamura, Takehiko; Maruyama, Yu

Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(2), p.113 - 127, 2013/06

On March 11, 2011, the Tohoku District - off the Pacific Ocean Earthquake and the subsequent tsunami resulted in the severe core damage at the TEPCO's Fukushima Dai-ichi Nuclear Power Station Units 1-3, involving hydrogen explosions at Units 1, 3, and 4 and the large release of radioactive materials to the environment. The four independent committees were established by the Government, the Diet of Japan and the Rebuild Japan Initiative Foundation as well as TEPCO to investigate the accident and published their respective reports. Also, the Nuclear and Industrial Safety Agency carried out the analysis of accident causes to obtain the lessons learned from the accident and made its report public. This article reviews the reports and clarifies the differences in their positions, from the technological point of view, focusing on the accident progression and causes. As well, the undiscussed issues are identified to provide insights useful for the near-term regulatory activities including accident investigation by the Nuclear Regulation Authority.

Journal Articles

Development of 20 kW input power coupler for 1.3 GHz ERL main linac; The High power test of the main linac coupler

Shinoe, Kenji*; Sato, Masato*; Sakai, Hiroshi*; Umemori, Kensei*; Nakamura, Norio*; Furuya, Takaaki*; Sawamura, Masaru; Cenni, E.*

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1026 - 1030, 2012/08

We are developing input couplers for ERL main linacs. Two couplers for cERL have been fabricated and high power test was carried out. A klystron was used for RF power source. The power was increased with a pulse mode of 10 usec with and 5 Hz repetition and reached to 100 kW. The average input power was increased by increasing the pulse width and repetition and finally reached 40 kW of CW mode.

Journal Articles

Development of 20 kW input power coupler for 1.3 GHz ERL main linac; The High power test of the prototype coupler

Shinoe, Kenji*; Sakai, Hiroshi*; Umemori, Kensei*; Cenni, E.*; Sawamura, Masaru; Nakamura, Norio*; Furuya, Takaaki*

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1300 - 1302, 2011/08

We are developing ERL main linac input coupler. Until now, prototypes of ceramic windows were created and performances were tested. Using this ceramic window, we produced a coupler prototype model. The coupler prototype was installed into an insulating vacuum chamber and cooled by liquid nitrogen, and the high power test was performed. This is the condition, where the coupler is actually used in a cryomodule. In this test, we were able to input 25 kW power. It was checked that the magnitude of generation of heat is also satisfactory. It was checked that this coupler fulfills the specification demanded from ERL main linac.

Journal Articles

High power tests of KEK-ERL input coupler for main linac under liquid nitrogen condition

Sakai, Hiroshi*; Furuya, Takaaki*; Nakamura, Norio*; Umemori, Kensei*; Shinoe, Kenji*; Sawamura, Masaru; Cenni, E.*

Proceedings of 15th International Conference on RF Superconductivity (SRF 2011) (Internet), p.356 - 360, 2011/07

We fabricated the prototype of an input coupler with two ceramic windows for ERL main linac and performed the high power test. In high power test, the one cold window was installed into the vacuum insulating chamber and cooled by liquid nitrogen. First, the multipacting limited the power level to 10 kW. The pulse processing method for 8 hours enabled the final power level to 25 kW with standing wave condition. We could also keep 20 kW power feeding into the coupler for 16 hours. The maximum measured temperature rises under feeding the 20 kW power to coupler were 120 K near the bellows parts and these are not so severe values to operate ERL main linac. The thermal cycle test of cold window of coupler was done. After 10-times thermal cycle tests between the room temperature and liquid nitrogen temperature, no leaks or cracks were observed. From these results of high power test, this prototype coupler satisfies our thermal and RF requirements.

Journal Articles

Generation and applications of ultra-short electron beams in energy-recovery linacs

Hajima, Ryoichi; Shimada, Miho*; Nakamura, Norio*

Nuclear Instruments and Methods in Physics Research A, 637(1, Suppl.), p.S37 - S42, 2011/05

 Times Cited Count:2 Percentile:21.25(Instruments & Instrumentation)

Energy-recovery linacs (ERLs) are in operation and under development in the world for future lightsources, which cover a wide range of photon energy, from THz to $$gamma$$-rays, by using various kinds of photo-emission processes, undulator radiation, free-electron lasers, laser Compton scattering (LCS), and coherent radiation. Availability of ultra-short electron beams is an essential feature of ERLs for future light sources. In this paper, we provide an overview of the generation and applications of ultra-short electron beams in ERLs. Magnetic bunch compression and velocity bunching are the two schemes of ultra-short electron beam generation that are presented with the Compact ERL test facility as an example.

Journal Articles

Development of 20 kW input power coupler for 1.3 GH ERL main linac; High power test of the renewed ceramic window

Shinoe, Kenji*; Sakai, Hiroshi*; Umemori, Kensei*; Sawamura, Masaru; Nakamura, Norio*; Furuya, Takaaki*

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.511 - 513, 2010/08

We started to develop an input power coupler for a 1.3 GHz ERL superconducting cavity for main linac. We fabricated power coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a CW 30 kW IOT power source. During this test, the ceramic window was broken by the sudden heat load. We found that this heat load occurred by the unexpected dipole mode. We renewed the ceramic window and successfully carried out the high power test up to CW 27 kW input power.

Journal Articles

Power coupler development for ERL main linac in Japan

Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2953 - 2955, 2010/05

We started to develop an input power coupler for a 1.3 GHz ERL superconducting cavity for main linac. We fabricated power coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a CW 30 kW IOT power source. During this test, the ceramic window was broken by the sudden heat load. We found that this heat load occurred by the unexpected dipole mode. We renewed the ceramic window and successfully carried out the high power test up to CW 27 kW input power.

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

Development of 20 kW input power coupler for 1.3 GHz ERL main linac; Component test at 30 kW IOT test stand

Sakai, Hiroshi*; Umemori, Kensei*; Sakanaka, Shogo*; Takahashi, Takeshi*; Furuya, Takaaki*; Shinoe, Kenji*; Ishii, Atsushi*; Nakamura, Norio*; Sawamura, Masaru

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.866 - 868, 2010/03

We started to develop an input coupler for a 1.3 GHz ERL superconducting cavity. Required input power is about 20 kW for the cavity acceleration field of 20 MV/m and the beam current of 100 mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied to the design for the CW 20 kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30 kW IOT power source and a test stand constructed for the high-power test. In this report, we mainly describe the results of the high-power test of ceramic window and bellows.

Journal Articles

Development of input power coupler for ERL main linac in Japan

Sakai, Hiroshi*; Furuya, Takaaki*; Sakanaka, Shogo*; Takahashi, Takeshi*; Umemori, Kensei*; Ishii, Atsushi*; Nakamura, Norio*; Shinoe, Kenji*; Sawamura, Masaru

Proceedings of 14th International Conference on RF Superconductivity (SRF 2009) (Internet), p.684 - 688, 2009/09

We started to develop an input coupler for a 1.3GHz ERL superconducting cavity for ERL main linac. Required input power is about 20kW for the cavity acceleration field of 20MV/m and the beam current of 100mA in energy recovery operation. The input coupler is designed based on the STF-BL input coupler and some modifications are applied for the CW 20kW power operation. We fabricated input coupler components such as ceramic windows and bellows and carried out the high-power test of the components by using a 30kW IOT power source and a test stand constructed.

Journal Articles

Tolerance study on RF amplitude and phase of main accelerating cavities and injection timing for the compact ERL

Nakamura, Norio*; Miyajima, Tsukasa*; Shimada, Miho*; Kobayashi, Yukinori*; Sakanaka, Shogo*; Hajima, Ryoichi

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.109 - 111, 2009/08

Tolerance study on RF amplitude and phase of main accelerating cavities and injection timing was performed for the compact ERL with a simulation code "elegant". As a result, it was found that errors of the RF amplitude and phase should be controlled within 0.01% and 0.01 deg. in rms to satisfy requirements for the arrival time and the bunch length at the exit of the 1st arc section in bunch-compression mode. In high-current and low-emittance modes, these control errors can be relaxed to 0.1% and 0.1deg. The injection timing error is allowed up to at least 200 fs, which does not deteriorate the beam quality at the exit of the 1st arc section in all the operation modes.

Journal Articles

Recent progress of construction for compact Energy Recover Linac

Kobayashi, Yukinori*; Sakanaka, Shogo*; Sato, Kotaro*; Kasuga, Toshio*; Kawata, Hiroshi*; Hajima, Ryoichi; Nakamura, Norio*

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.66 - 69, 2009/08

Future synchrotron light source based on the Energy Recovery Linac (ERL) is expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation with a potential of the oscillating type for X-ray free electron laser. We are constructing the R&D machine which is called the compact ERL including the developments of an ultra-low emittance electron gun and superconducting cavities for both the injector and the main linacs under the collaboration between KEK, JAEA, ISSP, and other institutes. In this paper, we report recent progress of the construction for the compact ERL with a repair of a KEK east counter hall.

Journal Articles

Research and development for future ERL light sources and construction of the compact ERL

Hajima, Ryoichi; Nakamura, Norio*; Sakanaka, Shogo*; Kobayashi, Yukinori*

Kasokuki, 6(2), p.149 - 157, 2009/07

Energy-recovery linac (ERL), which produces a small-emittance beam with high-average current, is a promising device for future light sources. In Japan, we have organized a collaboration team toward future ERL light sources and started R&D efforts to establish accelerator technologies for the ERL light sources. In this paper, we describe status of accelerator components R&D's and on-going construction of a test facility, the compact ERL.

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

JAEA Reports

Design study of the compact ERL

Hajima, Ryoichi; Nakamura, Norio*; Sakanaka, Shogo*; Kobayashi, Yukinori*

JAEA-Research 2008-032, 188 Pages, 2008/02

JAEA-Research-2008-032.pdf:23.41MB

Energy-recovery linac (ERL) is a promising device for future X-ray light sources. In Japan, we organized a Japanese ERL collaboration team, consisting of the members of KEK, JAEA, ISSP and other laboratories, and then, started R&D efforts for the future ERL light source. In order to demonstrate accelerator technologies relevant to the ERL light source, we have decided to build a small facility, Compact ERL. This report presents a design study of the Compact ERL, which includes R&D issues for each accelerator component, studies on beam dynamics, performance of the Compact ERL as a light source of THz and X-ray.

43 (Records 1-20 displayed on this page)