Composite with a glassy nonporous coordination polymer enhances gas adsorption selectivity

Zheng, X.*; Kato, Masaru*; Uemura, Yohei*; Matsumura, Daiju; Yagi, Ichizo*; Takahashi, Kiyonori*; Noro, Shinichiro*; Nakamura, Takayoshi*

Inorganic Chemistry, 62(3), p.1257 - 1263, 2023/01

https://doi.org/10.1021/acs.inorgchem.2c04068

Low temperature and pressure synthesis of lithium-nitride compound with HO addition on lithium target for BNCT

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Nihon Kinzoku Gakkai-Shi, 78(8), p.317 - 321, 2014/08

https://doi.org/10.2320/jinstmet.J2013078

Low temperature synthesis of lithium-nitride compound was conducted on the lithium target for BNCT by N/HO mixing gas squirt in the ultra high vacuum chamber, and the following results were derived; (1) Lithium-nitride compound was synthesized on the lithium target under 101.3 Pa N gas squirt at room temperature and in the ultra high vacuum chamber under the pressure of 110 Pa. (2) Remarkable contamination by O and C was observed on the lithium-nitride compound synthesized under the squirt pressure of 13.3-80 Pa/1.33-4.7 Pa N/HO mixing gas. (3) No contamination and synthesis of Li-N compound was observed under the squirt pressure of 0.013-0.027 Pa/0-0.005 Pa N/HO mixing gas. (4) Contamination by O and C was enhanced with excessive addition of HO at the pressure of over 1.33 Pa.

Direct synthesis of LiN thin layer on lithium target surface for BNCT in N gaseous conditions

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Nihon Kinzoku Gakkai-Shi, 78(4), p.137 - 141, 2014/04

https://doi.org/10.2320/jinstmet.J2013068

To prevent vaporization damage of BNCT (Boron Neutron Capture Therapy) lithium target during operation, direct synthesis of LiN thin layer on lithium target surface was demonstrated in 0.1 MPa N gas at temperature below 548 K and the following conclusions were derived; (1) Synthesis of LiN thin layer on lithium surface was confirmed after nitridation at 276548 K with surface contamination by oxygen and carbon. (2) Rapid nitridation over 1-5wt.%/min was observed above Li melting temperature, whereas slow reaction under 0.02-0.5 wt.%/min below melting temperature. (3) During nitridation, removal of oxygen contamination on LiN thin layer is taken place by nitrogen below Li melting temperature.

Annual report of Nuclear Emergency Assistance and Training Center (April 1, 2012 - March 31, 2013)

Sato, Takeshi; Muto, Shigeo; Okuno, Hiroshi; Katagiri, Hiromi; Akiyama, Kiyomitsu; Okamoto, Akiko; Koie, Masahiro; Ikeda, Takeshi; Nemotochi, Toshimasa; Saito, Toru; et al.

JAEA-Review 2013-046, 65 Pages, 2014/02

JAEA-Review-2013-046.pdf:11.18MB

When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) has the responsibility of providing technical support to the National government, local governments, police, fire stations and nuclear operators etc., because the JAEA has been designated as the Designated Public Institution under the Basic Act on Disaster Control Measures and the Act on Response to Armed Attack Situations, etc.. The Nuclear Emergency Assistance and Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an Off-Site Center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, dispatches specialists as required, and supplies the National Government and local governments with emergency equipments and materials. NEAT provides various exercise and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response organizations at normal times. The tasks of NEAT, with its past experiences as a designated public institution including the responses to TEPCO's Fukushima Accident, have been shifted to technical supports to the national government for strengthening its abilities to emergency responses; the NEAT therefore focused on maintenance and operation of its functions, and strengthening its response abilities in cooperation with the national government. This annual report summarized these activities of JAEA/NEAT in the fiscal year 2012.

Low temperature and pressure synthesis of lithium-nitride compound with HO addition on lithium target for BNCT

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Materials Transactions, 54(12), p.2233 - 2237, 2013/12

https://doi.org/10.2320/matertrans.M2013242

Low temperature synthesis of lithium-nitride compound was conducted on the lithium target for BNCT by N/HO mixing gas squirt in ultra high vacuum chamber, and the following results were derived; (1) Lithium-nitride compound was synthesized on lithium target under 101.3 PaN gas squirt at room temperature and 1 10 Pa in ultra high vacuum chamber. (2) Remarkable contamination by O and C was observed on the lithium-nitride compound synthesized by 13.3 80 Pa/1.33 4.7 Pa N/HO mixing gas squirt. (3) No contamination and synthesis of Li-N compound was observed at 0.013 0.027 Pa/0 0.005 Pa N/HO squirt. (4) Contamination by O and C is enhanced with excessive addition of over 1.33 Pa HO addition.

Thermal stability of BNCT neutron production target synthesized by lithium deposition and ion implantation

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Materials Transactions, 54(9), p.1760 - 1764, 2013/09

https://doi.org/10.2320/matertrans.M2013062

LiN synthesis on Li deposition layer was conducted without HO and O by lithium deposition in high vacuum chamber of 10 Pa and ion implantation techniques and the thermo-chemical stability of the LiN/Li/Cu tri-layered target under laser heating and air exposure was characterized by X-ray photoelectron spectroscopy. Following conclusions were derived; (1) LiN/Li/Cu tri- layered target with very low oxide and carbon contamination was synthesized by lithium deposition and ion implantation techniques without HO and O additions and frequent synthesis of the target is possible. (2) The evaporating temperature of Li deposited layer increased by 120 K after forming the LiN layer on the surface of Li. (3) Remarkable oxidation and carbon contamination were observed on the surfaces of Li/Cu and LiN/Li/Cu after air exposure and these contaminated compositions formed on the surface of LiN/Li/Cu was not removed by Ar heavy sputtering.

A Feasible DEMO blanket concept based on water cooled solid breeder

Someya, Yoji; Tobita, Kenji; Uto, Hiroyasu; Hoshino, Kazuo; Asakura, Nobuyuki; Nakamura, Makoto; Tanigawa, Hisashi; Enoeda, Mikio; Tanigawa, Hiroyasu; Nakamichi, Masaru; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03

This paper presents the conceptual design of a blanket with simplified structure whose interior consists of the mixture of breeder and multiplier pebble bed, cooling tubes and support for them only. Neutronics calculation indicated that the blanket satisfies a self-sufficient production of tritium. An important finding is that little decrease is seen in TBR even when the gap between neighboring blanket modules is as wide as 0.03 m. This means that blanket modules can be arranged with such a significant clearance gap without sacrifice of tritium production. On the other hand, the thickness of blanket housing is important from the viewpoint of safety. The blanket housing may rupture when the cooling pipe in the blanket is tearing, because thickness of structure materials is thin as 22 mm. This thickness is expected to maintain to 8 MPa in the steam pressure. Finally, the blanket housing, and aspect ratio of blanket shape is proposed in consideration of TBR, and engineering problem such as maintenance and manufacture are discussed.

In-situ vacuum deposition technique of lithium on neutron production target for BNCT

Ishiyama, Shintaro; Baba, Yuji; Fujii, Ryo*; Nakamura, Masaru*; Imahori, Yoshio*

Nuclear Instruments and Methods in Physics Research B, 288, p.18 - 22, 2012/10

https://doi.org/10.1016/j.nimb.2012.07.024

To achieve high performance of BNCT (Boron Neutron Capture Therapy) device, lithium target for neutron production was redesigned, and the layered structures of the synthesized target were characterized. Following conclusions were derived; (1) Uniform lithium layers with the thickness from 1.6 nm to a few hundreds nanometer were formed on Pd/Cu multilayer surface by in-situ vacuum deposition technique using metallic lithium as a source material. (2) Re-deposition of lithium layer on Li surface can be achieved by in-situ vacuum deposition technique. (3) Small amount of water and carbonate was observed on the top surface of Li. But the thickness of the adsorbed layer was less than monolayer, which will not affect the quality of the Li target. (4) The formation of Pd-Li alloy layer was observed at the Pd and Li interface. The alloy layer would contribute to the stability of the Li layer.

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

http://www.pasj.jp/web_publish/pasj9/proceedings/PDF/THPS/THPS053.pdf

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.

Effect of welding and coating on deuterium permeation through F82H

Nakamura, Hirofumi; Nakamichi, Masaru; Tanigawa, Hiroyasu; Yamanishi, Toshihiko

Journal of Nuclear Materials, 417(1-3), p.1150 - 1153, 2011/10

https://doi.org/10.1016/j.jnucmat.2011.01.098

Deuterium permeation characteristics through various surface states ofF82H such as F82H without surface treatment (bare F82H), welded F82H,and gold plated F82H (Au-F82H) have been investigated in order to understand the effect of surface state on permeation for the realistic tritium permeation evaluation in the fusion reactors especially breeding blanket system, which has many welding points and permeation reduction coatings. Based on obtained permeation behavior, the steady state permeation and the diffusivity derived form the transient permeation behavior have been discussed. As the results, deuterium permeation through bare F82H is smaller than that through clean surface F82H. Asto the effect of welding on permeation, the results indicate that significant difference of welding is not observed between bare F82H and welded F82H. Finally, gold plating on F82H showed good permeation reduction performance.