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Tanigawa, Hiroyasu; Gaganidze, E.*; Hirose, Takanori; Ando, Masami; Zinkle, S. J.*; Lindau, R.*; Diegele, E.*
Nuclear Fusion, 57(9), p.092004_1 - 092004_13, 2017/06
The current status of RAFM developments and evaluations, including the applicability of joining technologies, is reviewed. The technical challenges and potential risks of utilizing RAFM steels as the structural material of in-vessel components are discussed, and possible mitigation methodology is introduced. The discussion suggests that deuterium-tritium fusion neutron irradiation effects currently need to be treated as an ambiguity factor which could be incorporated within the safety factor. The safety factor will be defined by the engineering design criteria which are not yet developed with regard to irradiation effects and some high temperature process, and the operating time condition of the in-vessel component will be defined by the condition at which those ambiguities due to neutron irradiation become too large to be acceptable, or by the critical condition at which 14 MeV fusion neutron irradiation effects is expected to become different from fission neutron irradiation effects.
Hirose, Takanori; Sakasegawa, Hideo; Nakajima, Motoki; Tanigawa, Hiroyasu
Fusion Engineering and Design, 98-99, p.1982 - 1985, 2015/10
As a R&D activity on materials engineering for DEMO blanket in ITER-BA activity, characterization of F82H weld joints prepared with Tungsten-Inert-Gas (TIG) and electron beam (EB) have been investigated. In this work, 50 mm thick plates of F82H were welded using both processes. A similar-metal was employed as a filler for TIG welding. Post-weld-heat-treatment was conducted according to the conditions for Grade 91 defined as ASME P-No.15E, Group No.1. Although the maximum and the minimum hardness of the both joint are similar, the hardness distribution is quite different. The width of EB welds were smaller than that of TIG, and the hardness of EB weld metal was 10% higher than that of TIG. In the TIG welds, the strongest part was heat affected zone (HAZ) heated above phase transformation temperature, Ac1 and the hardness was very similar to the weld metal of EB joint, 280Hv. The hardness of TIG weld metal was around 260 Hv. Both welds demonstrated the smallest hardness, 180 Hv in the HAZ heated below Ac1 temperature. As a investigation of manufacturing process of box fabrication, second EB weld bead was perpendicularly put on the first EB bead. As a result, the second weld did not weaken the HAZ, but reduced the hardness of the weld metal to 260 Hv.
Ando, Masami; Nozawa, Takashi; Hirose, Takanori; Tanigawa, Hiroyasu; Wakai, Eiichi; Stoller, R. E.*; Myers, J.*
Fusion Science and Technology, 68(3), p.648 - 651, 2015/10
Times Cited Count：8 Percentile：46.31(Nuclear Science & Technology)Pressurized tubes of F82H and B-doped F82H irradiated at 573 and 673 K up to 
6dpa have been measured by a laser profilometer. The irradiation creep strain in F82H irradiated at 573 and 673 K was almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of 
BN-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573 K irradiation. For 673 K irradiation, the creep strain of some BN-F82H tubes was larger than that of F82H tubes. It is suggested that a swelling caused in each BN-F82H because small helium babbles might be produced by a reaction of B(n, 
) 
Li.
Nakajima, Motoki; Hirose, Takanori; Tanigawa, Hisashi; Enoeda, Mikio
Journal of Plasma and Fusion Research SERIES, Vol.11, p.69 - 72, 2015/03
Water-cooled blanket is an attractive concept for its compactness and its compatibility with the conventional technologies for PWR. For blanket application, the structural material is required to be as thin as possible for tritium breeding. On the other hand, it is also required the pressure tightness to withstand 15 MPa of internal pressure. Therefore it is necessary to understand the corrosion mechanism in high temperature pressurized water. The effects of water flow and DO in the test water on corrosion properties were investigated using rotating disk specimen in autoclave. In summary, the weight loss by flowing was occurred except for test with DO 8 ppm, and it was more pronounced at lower DO concentration. Since Fe
O
was observed on the specimen of small weight change, and the iron-poor layer thickness increased with decreasing the specimen weight, it seemed that the formation of FeO was effective for the suppression of weight loss.
Kanai, Akihiko*; Kasada, Ryuta*; Nakajima, Motoki; Hirose, Takanori; Tanigawa, Hisashi; Enoeda, Mikio; Konishi, Satoshi*
Journal of Nuclear Materials, 455(1-3), p.431 - 435, 2014/12
Times Cited Count：2 Percentile：14.58(Materials Science, Multidisciplinary)Kanai, Akihiko*; Park, C.*; Noborio, Kazuyuki*; Kasada, Ryuta*; Konishi, Satoshi*; Hirose, Takanori; Nozawa, Takashi; Tanigawa, Hiroyasu
Fusion Engineering and Design, 89(7-8), p.1653 - 1657, 2014/10
Times Cited Count：6 Percentile：39.20(Nuclear Science & Technology)Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Nakajima, Motoki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Hayashi, Takumi; Yamanishi, Toshihiko; et al.
Fusion Engineering and Design, 89(7-8), p.1131 - 1136, 2014/10
Times Cited Count：22 Percentile：81.74(Nuclear Science & Technology)The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. Regarding the fabrication technology development using F82H, the fabrication of a real scale mockup of the back wall of TBM was completed. Also the assembling of the complete box structure of the TBM mockup and planning of the pressurization testing was studied. The development of advanced breeder and multiplier pebbles for higher chemical stability was performed for future DEMO blanket application. From the view point of TBM test result evaluation and DEMO blanket performance design, the development of the blanket tritium simulation technology, investigation of the TBM neutronics measurement technology and the evaluation of tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been performed.
Sato, Satoshi; Tanigawa, Hisashi; Hirose, Takanori; Enoeda, Mikio; Ochiai, Kentaro; Konno, Chikara
Fusion Engineering and Design, 89(9-10), p.1984 - 1988, 2014/10
Times Cited Count：2 Percentile：14.58(Nuclear Science & Technology)In order to evaluate nuclear properties of the ITER JA WCCB-TBM (Water Cooled Ceramic Breeder Test Blanket Module) and ensure that the design conforms to the nuclear regulation for licensing, nuclear analyses have been performed for the WCCB-TBM including flame, shield, pipe-forest, bio-shield and AEU (Ancillary Equipment Unit). Nuclear analyses are performed with the Monte Carlo code MCNP5.14, activation code ACT-4 and Fusion Evaluated Nuclear Data Library FENDL-2.1. MCNP geometry input data of the TBM is created from CAD data with the automatic conversion code GEOMIT, and other geometry input data is created by manually. By adopting the dog-leg gaps, decay 
-ray dose rate can be drastically reduced and hands-on access is possible for shield. Detailed calculation results will be presented in this symposium.
Hirose, Takanori; Nozawa, Takashi; Stoller, R. E.*; Hamaguchi, Dai; Sakasegawa, Hideo; Tanigawa, Hisashi; Tanigawa, Hiroyasu; Enoeda, Mikio; Kato, Yutai*; Snead, L. L.*
Fusion Engineering and Design, 89(7-8), p.1595 - 1599, 2014/10
Times Cited Count：51 Percentile：96.00(Nuclear Science & Technology)The material properties, focusing on the properties used for design analysis were re-assessed and newly investigated for various heats including F82H-IEA. Moreover, irradiation effects on those properties were studied in this work. As for thermal properties, thermal conductivity that has significant impacts on the thermo-hydraulic properties of the blanket was investigated on several heats of F82H including F82H-IEA. According to the measurements, the thermal conductivity falls in the range 28.3
1.1 W/m/K at 293 K. Although this is comparable with that of the other ferritic/martensitic steels, it is 20% lower than the published value for F82H-IEA. The re-assessment on the published value revealed that the thermal diffusivity was over-estimated. As for irradiation effects on the physical properties, electric resistivity was measured after irradiation up to 6 dpa at 573 K and 673 K. The reduction of resistivity in F82H and its welds were 3% and 6%, respectively.
Ando, Masanori; Hirose, Yuichi*; Karato, Takanori*; Watanabe, Sota*; Inoue, Osamu*; Kawasaki, Nobuchika; Enuma, Yasuhiro*
Journal of Pressure Vessel Technology, 136(4), p.041406_1 - 041406_10, 2014/08
Times Cited Count：13 Percentile：50.30(Engineering, Mechanical)To compare and assess the creep-fatigue life evaluation methods for stress concentration point, a series of creep-fatigue test was performed with notched specimens made of Mod.9Cr-1Mo steel. Mechanical creep-fatigue tests and thermal creep-fatigue test were performed. A series of Finite Element Analysis was also carried out to predict the number of cycles to failure by the several creep-fatigue life evaluation methods. Then these predictions were compared with the test results. Several types of evaluation methods such are stress redistribution locus (SRL) method, simple elastic follow-up method and the methods described in the JSME FRs code were applied. Through the comparisons, it was appeared that SRL method gave rational conservative prediction of the creep-fatigue life for all conditions tested in this study. The JSME FRs code gave an evaluation over 70 times conservative lives comparing with the test results.
Ando, Masami; Nozawa, Takashi; Hirose, Takanori; Tanigawa, Hiroyasu
Purazuma, Kaku Yugo Gakkai-Shi, 90(1), p.64 - 67, 2014/01
Reduced activation ferritic/martensitic steel (RAFM) is a candidate for the material of DEMO blanket structure. The irradiation creep behavior of F82H and JLF-1 steel has been measured at 300, 400 and 500
C up to 5 dpa using helium-pressurized creep tubes irradiated in HFIR. These tubes were pressurized with helium to hoop stress levels of 0400 MPa at the irradiation temperature. The results for F82H and JLF-1 with a 400 MPa hoop stress detected small creep strains (
0.25%) after irradiation at 300C. Irradiation creep rate (creep strain/dose) was tendency to be a similar behavior for high-dose irradiated RAFM specimens in FFTF. In this paper, a procedure of irradiation creep test & evaluation was also summarized.
Hirose, Takanori; Someya, Yoji; Tanigawa, Hisashi; Suzuki, Satoshi
Yosetsu Gakkai-Shi, 83(1), p.70 - 77, 2014/01
no abstracts in English
Hirose, Takanori; Sokolov, M. A.*; Ando, Masami; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Stoller, R. E.*; Odette, G. R.*
Journal of Nuclear Materials, 442(1-3), p.S557 - S561, 2013/11
Times Cited Count：10 Percentile：57.49(Materials Science, Multidisciplinary)Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Suzuki, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Yamanishi, Toshihiko; Hoshino, Tsuyoshi; Nakamichi, Masaru; et al.
Fusion Engineering and Design, 87(7-8), p.1363 - 1369, 2012/08
Times Cited Count：37 Percentile：91.01(Nuclear Science & Technology)The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. Fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.
Seki, Yohji; Yoshikawa, Akira; Tanigawa, Hisashi; Hirose, Takanori; Ezato, Koichiro; Enoeda, Mikio; Sakamoto, Kensaku
Dai-17-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.265 - 266, 2012/06
In the case of a water cooled ceramic breeder in a blanket, pebbles of a ceramic tritium breeder are packed in a container constituted by a partition plate. Helium purge gas is applied as a transport fluid in a tritium recovery system. It is of importance to build database of a pressure drop as part of a design of the tritium recovery system. In this experimental study, the pressure drops of He gas through pebble bed were measured within the wide range of a flow rate up to 100 L/min. The results indicate that a laminar flow is dominant and the pressure drop was correctly predicted by the empirical equation within a part of flow rate. Reliability of prediction ability of pressure drop was established by this experiment within the flow rate which is less than 60 L/min. Moreover, this paper describes that slight difference between the experimental result and the empirical equation within a range of flow rate from 60 L/min to 100 L/min.
Shiba, Kiyoyuki; Tanigawa, Hiroyasu; Hirose, Takanori; Sakasegawa, Hideo; Jitsukawa, Shiro
Fusion Engineering and Design, 86(12), p.2895 - 2899, 2011/12
Times Cited Count：45 Percentile：93.85(Nuclear Science & Technology)Aging properties of reduced activation ferritic/martensitic steel F82H was researched at temperature ranging from 400C to 650C up to 100,000 hr. Microstructure, tensile, and Charpy properties were carried out. Laves was found at temperatures between 550 and 650C and M
C carbides were found at the temperatures between 500 and 600C over 10,000 hr. These precipitates caused degradation in toughness, especially at temperatures ranging from 550C to 650C. Tensile properties do not have serious aging effect, except for 650C, which caused large softening even after 10.000 hr. Increase of precipitates also causes some degradation in ductility, but it is not critical. Large increase in DBTT caused by the large Laves phase precipitation at grain boundary was observed in the 650C aging. Laves precipitates at grain boundary also degrades the USE of the aged materials. These aging test results provide F82H can be used up to 30,000 hr at 550C.
Seki, Yohji; Hirose, Takanori; Tanigawa, Hisashi; Enoeda, Mikio
Proceedings of Plasma Conference 2011 (PLASMA 2011) (CD-ROM), 2 Pages, 2011/11
Development of test blanket module (TBM) with a water cooled solid breeder is being performed as the primary candidate of ITER-TBM of Japan. Prior to the installation of each TBM, it is necessary to develop the capability of the prediction analyses of all essential functions of the blanket to validate the analyses tools by the TBM. Especially the prediction tool of tritium concentration in the blanket system is one of the most important issues to control tritium recovery. From this view point, this paper discusses the flow phenomena and the tritium transport of the helium purge gas in the pebble bed. By prediction of purge gas flow using a numerical simulation, the result indicates tritium concentration depended on the position of the breeder layer. Namely, the large concentration still remains near the wall with approaching to an outlet.
Hirose, Takanori; Tanigawa, Hisashi; Yoshikawa, Akira; Seki, Yohji; Tsuru, Daigo; Yokoyama, Kenji; Ezato, Koichiro; Suzuki, Satoshi; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design, 86(9-11), p.2265 - 2268, 2011/10
Times Cited Count：5 Percentile：36.25(Nuclear Science & Technology)As one of the most important fabrication technologies of the WCCB TBM, Hot Isostatic Pressing (HIP) joining technology was selected to fabricate the first wall with built-in cooling channel structure made of reduced activation martensitic/ferritic steel, F82H. By using developed HIP technology, a real scale TBM first wall mockup was successfully fabricated. High heat flux test of the fabricated mockup showed the feasibility to with the equivalent conditions of the WCCB TBM operation. The breeder pebble box was successfully fabricated with thin wall cooling pipes and thin plate sleds by Laser welding. With respect to the side walls with built in cooling channels were also fabricated using drilling technology. Assembling of the first wall and side walls is one of the critical fabrication processes of the fabrication of the TBM structure. By using a F82H first wall mockup and side wall mockups, assembling process was demonstrated successfully by Electron Beam welding.
Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Sakasegawa, Hideo; Hirose, Takanori; Jitsukawa, Shiro
Fusion Engineering and Design, 86(9-11), p.2549 - 2552, 2011/10
Reduced activation ferritic/martensitic (RAFM) steels are recognized as the primary candidate structural materials for fusion blanket systems, and it is expected to have sound engineering bases, such as fabrication technology and materials database to use RAFM as the structural materials for pressure equipment. It is also important to develop irradiation database and design methodology of fusion neutron irradiated structure to use RAFM as the structural material for fusion neutron irradiated pressure equipment. In the International Fusion Energy Research Centre (IFERC) project in the Broader Approach (BA) activities between EU and Japan, R&D on RAFM steel is underway and these are expected be the bases for DEMO design criteria and licensing. The objective of this paper is to review the BA R&D status of RAFM steel, especially F82H development in Japan. The identified key technical issues for the design and fabrication of DEMO blanket and recent achievements in Japan were introduced.
Okubo, Nariaki; Sokolov, M. A.*; Tanigawa, Hiroyasu; Hirose, Takanori; Jitsukawa, Shiro; Sawai, Tomotsugu; Odette, G. R.*; Stoller, R. E.*
Journal of Nuclear Materials, 417(1-3), p.112 - 114, 2011/10
Times Cited Count：10 Percentile：57.67(Materials Science, Multidisciplinary)Irradiation hardening and fracture toughness of reduced-activation ferritic/martensitic steel F82H after irradiation were investigated with a focus on changing the fracture toughness transition temperature as a result of several heat treatments. The specimens were standard F82H-IEA (IEA), F82H-IEA with several heat treatments (Mod1 series) and a higher tantalum containing (0.1%) heat of F82H (Mod3). The specimens were irradiated up to 18 dpa at 300 C in High Flux Isotope Reactor under a collaborative research program between JAEA/US-DOE. The results of hardness tests showed that irradiation hardening of IEA was comparable with that of Mod3. However, the fracture toughness transition temperature of Mod3 was lower than that of IEA. The transition temperature of Mod1 was also lower than that of the IEA heat. These results suggest that tightening of specifications on the heat treatment condition and modification of the minor alloying elements seem to be effective to reduce the fracture toughness transition temperature after irradiation.
