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Kaito, Takeji; Otsuka, Satoshi; Yano, Yasuhide; Tanno, Takashi
Nuclear Materials Letters (Internet), p.29 - 43, 2022/12
no abstracts in English
Asayama, Tai; Otsuka, Satoshi
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 15 Pages, 2017/06
This paper summarizes ongoing efforts in Japan Atomic Energy Agency on the development of core and structural materials for sodium-cooled fast reactors. For core materials, oxide dispersion strengthened (ODS) steels and 11Cr ferritic steel (PNC-FMS) will be used for the fuel pin cladding and wrapper tube, respectively. As for ODS steel, 9Cr- and 11Cr-ODS steels have been extensively developed. Their laboratory-scale manufacturing technology has been developed including reliability improvement in tube microstructure and strength homogeneity. As for the PNC-FMS wrapper tube, the development of a dissimilar joining technique with type 316 steel and properties evaluation of dissimilar welds have been carried out. For structural materials, codification of 316FR stainless steel and Modified 9Cr-1Mo steel is ongoing. Acquisition and collection of long-term data of base metal and welded joints are continued and evaluation methodologies are being developed to establish a technical basis for 60-year design.
;
JNC TN9400 2000-035, 164 Pages, 2000/03
JNC-TN9400-2000-035.pdf:3.67MB
High Strength Ferritic/Martensitic Steel (PNC-FMS : 0.12C-11Cr-0,5Mo-2W-0.2V-0.05Nb), developed by JNC, is one of the candidate materials for the long-life core of large-scale fast breeder reactor. Ductile brittle transition temperature (DBTT) was tentatively determined in 1992 in material design base standard of PNC-FMS. Howevcr, specimen size effect on impact property and upper shelf energy (USE) have not been evaluated. ln this study, effects of specimen size, thermal aging and neutron irradiation on the charpy impact property of PNC-FMS were evaluated, using together with recently obtained data. The design value of USE and DBTT as fabricated and each correlation of aging and irradiation effects were determined. The results are summarized as follows. (1)lt was found that USE is related to (Bb) as USE=m(Bb)
, where B is specimen width, b is ligament size and both m and n are constant. For PNC-FMS, n value is equal to 1.4. It's possible to determine n value from USE (J) for full size specimen using the correlation: n=1.38
10
USE + 1.20. (2)lt was clarified that DBTT is correlated with (BKt) as DBTT=p(log
BKt)+q, where Kt is elastic stress concentration factor and both p and q are constant. For PNC-FMS, the correlation is as follows: DBTT=119(logBKt)-160. (3)DBTT estimated at the irradiation temperature from 350 to 650 
C for sub size specimen (width and height are 3 and 10 mm, respectively), was below 180 C, based on the design value of DBTT as fabricated and each correlation of aging and irradiation effects.
Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Fracture toughness is an important property when ferritic martensitic steel (FMS) is irradiated and thermally aged. The goal of this study is to develop reasonably miniaturized fracture toughness test technique which can be applied for irradiated or sampled from welded small specimen. In this phase, the capability of miniature 3-point bend (3PB) test technique for evaluating toughness, and the side groove effect on miniatured specimen were confirmed. A miniature 3PB type J test conforming to ASTM 1820 was applied to the PNC-FMS developed for the fast reactor. The effect of the root radius of the side groove that controls the crack propagation was verified for the specimen miniaturized to 5 mm thickness, 3 mm width and 22.5 mm length according to the thickness of the wrapper tube. The crack winded and/or branched with root radius of 0.5 mm, the standard size of ASTM1820. But by making it 0.05 mm, it was possible to control the crack propagation along the side groove. As a result, J
= 300 kJ/m
was obtained, and a prospect of this technique was obtained for the fracture toughness evaluation of the wrapper tube by improving the side groove.
Tanno, Takashi; Yano, Yasuhide; Oka, Hiroshi*; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, it was clarified that pre-crack length and open angle of side groove are important to obtain the certain and conservative fracture toughness with miniatured specimen. Finally, the fracture toughness value J
of PNC-FMS could be obtained with miniaturized specimen which can be applied to wrapper tube thickness.
Tanno, Takashi; Fujita, Koji; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, the anisotropy in toughness of rolled PNC-FMS was successfully confirmed with the specimen which was modified in the geometry. In addition, it was confirmed that data can be obtained with good reproducibility for specimens having plural geometries.
Yano, Yasuhide
no journal, ,
no abstracts in English
Kaito, Takeji; Otsuka, Satoshi; Yano, Yasuhide; Tanno, Takashi
no journal, ,
no abstracts in English
Tanno, Takashi; Fujita, Koji; Shizukawa, Yuta
no journal, ,
no abstracts in English
Yano, Yasuhide; Tanno, Takashi; Otsuka, Satoshi; Mitsuhara, Masatoshi*; Nakashima, Hideharu*; Toyama, Takeshi*; Onuma, Masato*
no journal, ,
no abstracts in English
Tanno, Takashi; Shizukawa, Yuta; Fujita, Koji
no journal, ,
The evaluation of the fracture toughness of thermal-aged PNC-FMS was conducted using the miniature three-point bending fracture toughness evaluation technique under development. The results implied that although the Charpy impact properties of PNC-FMS after thermal aging for 6000 hours at 600C degraded, the fracture toughness at room temperature did not degraded. Furthermore, as a result of comparing the cases where fatigue pre-crack was introduced to the test specimen before and after thermal aging, it was found that there was no significant difference under the present thermal aging conditions.
Tanno, Takashi; Shizukawa, Yuta
no journal, ,
The miniature fracture toughness technique (3-point bending J test) which is being developed by JAEA, was applied to PNC-FMS/SUS316 dissimilar weld joint made by electron beam welding technology. The side grooves on the specimens ensured straight propagation of the crack, and the fracture toughness of a narrow weld metal with different base metals was successfully evaluated. The fracture toughness value of the weld metal was found to be at least the same as that in the TL direction of PNC-FMS base metal.
Tanno, Takashi; Yano, Yasuhide; Sekio, Yoshihiro; Oka, Hiroshi; Otsuka, Satoshi; Kaito, Takeji; Tachi, Yoshiaki
no journal, ,
Ferritic/martensitic (F/M) steels are candidate for core material of fast reactors (FR) because of its superior swelling resistance. A 11Cr F/M steel (PNC-FMS) have been developed for wrapper tube and cladding tube of demonstration FR in Japan Atomic Energy Agency. For demonstration of in-reactor performance and preparation of material strength standard, it is important to extend database on irradiation and thermal aging effects. In this work, ring tensile tests and hardness tests of PNC-FMS irradiated in Joyo up to 32.5 dpa at 455-835 C were carried out, and the results were compared with those of aging tests in order to clarify the irradiation effects exclusive of thermal aging effects. The UTS at RT of PNC-FMS irradiated at over 600 C tended to be lower than those of as-received and/or thermal aged ones. The hardness showed the same trend. But, the UTS and hardness test results showed that PNC-FMS irradiated at 835 C could be harder than that of aged one.
Tanno, Takashi; Yano, Yasuhide; Oka, Hiroshi; Sekio, Yoshihiro; Otsuka, Satoshi; Kaito, Takeji; Tachi, Yoshiaki
no journal, ,
Ferritic/martensitic (F/M) steels are candidate for core material of fast reactors (FR) because of its superior swelling resistance. A 11Cr F/M steel (PNC-FMS) have been developed for wrapper tube and cladding tube for FR in JAEA. For demonstration of in-reactor performance and preparation of material strength standard, it is important to extend database on irradiation and thermal aging effects. In this work, ring tensile tests and hardness tests of PNC-FMS irradiated in Joyo up to 32.5 dpa at 455-835 C were carried out, and the results were compared with those of aging tests to clarify the irradiation effects exclusive of thermal aging effects. The UTS and hardness at RT of PNC-FMS irradiated at over 600 C tended to be lower than those of as-received and/or thermal aged ones. The facts indicate evident irradiation softening. On the other hand, PNC-FMS irradiated at 835 C was harder than that of aged one. Transformation during irradiation would be the cause.