R&D activities of tritium technologies on Broader Approach in Phase 2-2

Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.

Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10

https://doi.org/10.1016/j.fusengdes.2015.06.075

Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.

Overview of R&D activities on tritium processing and handling technology in JAEA

Yamanishi, Toshihiko; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Oyaizu, Makoto; Yamada, Masayuki; Suzuki, Takumi; Hayashi, Takumi

Fusion Engineering and Design, 87(5-6), p.890 - 895, 2012/08

https://doi.org/10.1016/j.fusengdes.2012.02.043

In JAEA, the tritium processing and handling technologies have been studied at TPL. The main basic R&D activities in this field are: the tritium processing technology for the blanket recovery system; the tritium behavior in a confinement; and detritiation and decontamination. The R&D for tritium processing and handling technologies to a demonstration reactor (DEMO) are also planned to be carried out in the Broader Approach (BA) program in Japan by JAEA with Japanese universities. The ceramic electrolysis cell has been studied as a tritium processing method for the blanket system. The permeation behavior of tritium through pure iron into the gas containing water vapor has been studied. As for the behavior of high concentration tritium water, it was observed that the formation of the oxidized layer was prevented by the presence of tritium in water. Tritium durability tests were also carried out for the electrolysis cell of the chemical exchange column.

Improvement of ultimate pressure of oil-free reciprocating pump for tritium service

Hayashi, Takumi; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko

Fusion Science and Technology, 60(3), p.1101 - 1104, 2011/10

https://doi.org/10.13182/FST11-A12607

Prototype manufacturing of small tritium target inside JAEA

Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru; Kutsukake, Chuzo; Oginuma, Yoshikazu; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko; Konno, Chikara

Journal of Plasma and Fusion Research SERIES, Vol.9, p.338 - 341, 2010/08

We have conducted a small tritium target production R&D for FNS inside JAEA. The tritium target is produced by adsorbing tritium in a thin titanium layer. Since titanium is very active to oxygen, glow discharge cleaning was carried out to remove an oxidation film of the titanium surface. Through many tests with deuterium, we found out that it was not an oxidation film but humidity to disturb tritium absorption. The following procedures were necessary; (1) to outgas the inside of an absorption chamber, (2) to keep environmental humidity under 3% in handling the titanium-deposited substrate, (3) to keep the titanium-deposited target substrate in the vacuum. The DT neutron generation performance of the tritium target produced with the above procedures was the same as that with discharge cleaning. The manufacture condition of the small target was established.

Recent results of R&D activities on tritium technologies for ITER and fusion reactors at TPL of JAEA

Yamanishi, Toshihiko; Hayashi, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Arita, Tadaaki; Hoshi, Shuichi; et al.

Fusion Engineering and Design, 83(10-12), p.1359 - 1363, 2008/12

https://doi.org/10.1016/j.fusengdes.2008.08.010

At TPL (Tritium Process Laboratory) of JAEA, ITER relevant tritium technologies have been studied. The design studies of Air Detritiation System have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the research of the tritium recovery system of ITER test blanket system. A ceramic proton conductor has been studied as an advanced blanket system. A series of fundamental studies on tritium safety technologies not only for ITER but also for fusion DEMO plants has also been carried out at TPL of JAEA. The main research activities in this field are the tritium behavior in a confinement and its barrier materials; monitoring; accountancy; detritiation and decontamination etc. In this paper, the results of above recent activities at TPL of JAEA are summarized from viewpoint of ITER relevant and future fusion DEMO reactors.

Tritium safety study using caisson assembly (CATS) at TPL/JAEA

Hayashi, Takumi; Kobayashi, Kazuhiro; Iwai, Yasunori; Isobe, Kanetsugu; Nakamura, Hirofumi; Kawamura, Yoshinori; Shu, Wataru; Suzuki, Takumi; Yamada, Masayuki; Yamanishi, Toshihiko

Fusion Science and Technology, 54(1), p.319 - 322, 2008/07

https://doi.org/10.13182/FST08-A1822

Studies on the behavior of tritium in components and structure materials of tritium confinement and detritiation systems of ITER

Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; et al.

Nuclear Fusion, 47(12), p.1645 - 1651, 2007/12

https://doi.org/10.1088/0029-5515/47/12/001

The confinement and removal of tritium are the key subjects for safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell building, tritium is often released, as vapor and is in contact with the inner walls. Also those of an ITER tritium plant building will be exposed to tritium in an accident. However, the data are scarce, especially on the penetration of tritium into the concrete of the wall materials. The tritium released in the buildings is removed by the Atmosphere Detritiation Systems (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF is used in ITER, and is expected to be released in an accident such as fire. Although the SF gas has the potential as a catalyst poison, the performance of ADS with the existence of SF has not been confirmed yet. Tritiated water is produced in the regeneration process of ADS, and is subsequently processed by the ITER Water Detritiation System (WDS). One of the key components of WDS is an electrolysis cell. The electrolysis cell is made of organic compounds, and there is no data on the durability of the cell exposed to tritium. To overcome these issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behavior in concrete; (2) effect of SF on performance of ADS; and (3) tritium durability of electrolysis cell of ITER-WDS.

Isotope effect of hydrogen rapidly supplied from the metal storage bed

Hayashi, Takumi; Suzuki, Takumi; Shu, Wataru; Yamanishi, Toshihiko

Fusion Science and Technology, 52(3), p.706 - 710, 2007/10

https://doi.org/10.13182/FST07-A1573

In the tritium Storage and Delivery System (SDS) of ITER, how to control the isotope balance of DT fuel is one of the key issues for the stable and optimum operation. Basically, the equilibrium pressure of hydrogen-metal system has large isotope effect such as PH PD PT, however, there is only a limited data of the isotope composition of hydrogen mixture, which is supplied rapidly from the storage bed by a vacuum pump under ITER/SDS conditions. Therefore, in order to investigate the isotope composition of supplied hydrogen gases, a series of rapid supply experiments was performed using a 1/10 ITER scale ZrCo bed with a scroll pump as functions of bed temperature (573 K 623 K) and isotope composition of hydrogen mixture stored initially (H:D = 1:9 9:1). The isotope composition was measured by in-line mass spectrometer during continuous hydrogen supply. In this paper, the above results are summarized and the isotope effect is discussed. The effective way to control the isotope balance of DT fuel is also discussed with more moderate SDS design conditions.

Monitoring of tritium in diluted gases by detecting bremsstrahlung X-rays

Shu, Wataru; Matsuyama, Masao*; Suzuki, Takumi; Nishi, Masataka

Fusion Engineering and Design, 81(1-7), p.803 - 808, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.05.006

In this work, the counting rate of bremsstrahlung X-rays was measured against the tritium partial pressure in two mixed gases diluted with helium or hydrogen. Subsequently, the counting rate was also measured against total pressure for T-He mixture at a constant tritium partial pressure of 93 Pa or 1.3 kPa. For both mixtures, the counting rate of bremsstrahlung X-rays decreased linearly with the decreasing tritium partial pressure when the total pressure is smaller than about 10 kPa. At higher pressures, the deviation from the linear relationship appeared due to absorption of beta-particles in the gas phase, and this can be decreased by some commercially available arrangements. On the other hand, the counting rate of bremsstrahlung X-rays depended only upon the tritium partial pressure when absorption of beta-particles in the gas phase is negligibly small. The results obtained show that this method of tritium monitoring is very promising for the fuel processing system of fusion reactors, especially for tritium recovery system of breeding blankets.

Radiochemical reactions between tritium molecule and carbon dioxide

Shu, Wataru; Ohira, Shigeru; Suzuki, Takumi; Nishi, Masataka

Fusion Science and Technology, 48(1), p.684 - 687, 2005/07

https://doi.org/10.13182/FST05-A1016

As part of a series of studies on radiochemical reactions that may take place in the fuel processing systems of a future D-T fusion machine like the ITER, reactions of tritium molecule (T) and carbon dioxide (CO) were examined by laser Raman spectroscopy and quadrupole mass spectrometry (QMS). Both T and CO decreased rapidly in the first 30 minutes after mixing, and then the reactions between them became much slower. As the predominant products of the reactions, carbon monoxide (CO) and tritiated water (TO) were found in gaseous phase and condensed phase, respectively. However, there existed also some solid products that were thermally decomposed to CO, CO, T, TO, etc. during baking at 150C and 250C.