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Shobu, Takahisa; Shiro, Ayumi*; Kono, Fumiaki*; Muramatsu, Toshiharu; Yamada, Tomonori; Naganuma, Masayuki; Ozawa, Takayuki
Quantum Beam Science (Internet), 5(2), p.17_1 - 17_9, 2021/06
The automotive industries employ laser beam welding because it realizes a high energy density without generating irradiation marks on the opposite side of the irradiated surface. Typical measurement techniques such as strain gauges and tube X-rays cannot assess the localized strain at a joint weld. Herein high-energy synchrotron radiation X-ray diffraction was used to study the internal strain distribution of laser lap joint PNC-FMS steels (2- and 5-mm thick) under loading at a high temperature. As the tensile load increased, the local tensile and compressive strains increased near the interface. These changes agreed well with the finite element analysis results. However, it is essential to complementarily utilize internal defect observations by X-ray transmission imaging because the results depend on the defects generated by laser processing.
Kono, Fumiaki; Sogame, Motomu; Yamada, Tomonori; Shobu, Takahisa; Naganuma, Masayuki; Ozawa, Takayuki; Muramatsu, Toshiharu
JAEA-Technology 2015-004, 57 Pages, 2015/03
JAEA-Technology-2015-004.pdf:20.87MB
Laser welding of ferritic/martensitic steel (PNC-FMS) sheets with different thicknesses (2 mm and 5 mm) was examined to investigate the weldability between the inner and outer duct in fast reactor fuel assemblies with inner duct structure (FAIDUS); the objective of the inner duct is to avoid the re-criticality in case of the core melting accident. Laser-spot and melt-run welding was performed at various laser powers, welding times and velocities to find out the appropriate welding conditions with few defects and enough penetration depth. As for the spot welding, furthermore, slow cooling rate or pulsed laser irradiation could reduce the crack and porosity in the welded zone. The strain of the welded zone almost disappeared and the hardness was comparable with that of the base metal by applying post welding heat treatment at 690 
C for 103 min. In addition, the shear strength of welded joints was confirmed to be sufficiently higher than the provisional allowance shear stress. These results indicate that laser welding would be probably applied to the PNC-FMS inner and outer ducts.
Morihira, Masayuki; Ozawa, Takayuki; ; Suzuki, Masahiro; Shigetome, Yoshiaki; Kihara, Yoshiyuki; Kono, Shusaku
JNC TN8400 2004-014, 193 Pages, 2004/07
JNC-TN8400-2004-014.pdf:24.52MB
The collaboration project concerning sphere-pac fuel among JNC, Swiss PSI (Paul Scherrer Institut) and Dutch NRG (Nuclear Research and Consultancy Group) is in progress.Final target of the project is comparative irradiation tests of Sphere-pac fuel in the HFR (High Flux Reactor) in Petten in the Netherlands with pellet type fuel and vipack fuel. Total 16 fuel segments (8 pins) of these three types of fuel are planned to be irradiated. Two sphere-pac fuel segments contain 5%Np in addition to 20%Pu-MOX. Other segments contain no Np. Fabrication of irradiation test pins was completed till May 2003 in PSI. After transportation of the fuel pins to Petten, two times of irradiation were performed in January to March in 2004 and now post irradiation tests are in progress. Later two irradiations will be done till the autumn in 2004.This report summarized the basic plan, fuel design, and fabrication of irradiation test pins concerning this collaboration project.
Ozawa, Takayuki; Abe, Tomoyuki; Kono, Shusaku; Franz, I.*; Hannu Wall*
P.279, P. 279, 2002/00
None
Ojima, Hisao; Hayashi, Shotaro; Kawano, Takayuki
Nihon Genshiryoku Gakkai-Shi, 31(11), 1273 Pages, 1989/11
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)*; *; *; *
PNC TN941 82-246VOL1, 92 Pages, 1982/11
PNC-TN941-82-246VOL1.pdf:3.39MB
The Component Test Loop (CTL) has been operated for several kinds of tests under mechanical and thermal conditions similar to reactor "Fugen". Its water chemistry has been controlled by all-volatile-treatment (AVT) for inhibiting corrosion of the loop components and piping which is composed of carbon steel. The CTL has a schedule of performing corrosion tests of main components and materials used in "Fugen". For these tests, the CTL is required to simulate water chemistry of the real reactors and to operate under neutral water condition. However, there is no experience of operating carbon steel boilers with neutral water treatment (NWT) in Japan. Therefore, preliminary tests were done to examine the possibility of NWT operation of the CTL and to make clear what kinds of apparatus to be added to the loop. Test results are as follows. (1)Throughout a period of steady state operation of the CTL with neutral water treatment, the following water chemistry was obtained at the inlet of a test section; electrical conductivity: 0.3
S/cm, disolved oxygen: 150ppb, PH: 6.25, total iron: 2.5ppb, total cupper: 15-20ppb, SiO
: 25ppb, organie impurity (UV value): 0.005. These values are totally close to those of the primary coolant of reactor "Fugen", and indicates that the CTL can be operated under a water condition simulating "Fugen". (2)The total iron content of 2.5 ppb under neutral water conditions is 1/4 to 1/2 times as low as that under AVT water conditions, and indicates neutral water treatment is excellent anti-corrosive treatment for carbon steel pipings. (3)It was found that cupper, SiO and organic impurities had been accumulated in the CTL through the past 10 years. Where these impurities come from and how to remove them from the loop are discussed. (4)Corrosion tests of iron, cupper and its alloy specimens showed cupper and its alloy are much corrosive than iron under the neutral water condition. 0bservation and analysis of inner surfaces ...
Kono, Fumiaki; Sogame, Motomu; Yamada, Tomonori; Shobu, Takahisa; Ozawa, Takayuki; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Shobu, Takahisa; Zhang, S.; Shiro, Ayumi; Yamada, Tomonori; Muramatsu, Toshiharu; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Shobu, Takahisa; Zhang, S.; Shiro, Ayumi; Muramatsu, Toshiharu; Yamada, Tomonori; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Shobu, Takahisa; Zhang, S.; Shiro, Ayumi; Muramatsu, Toshiharu; Yamada, Tomonori; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
In order to clarify an anneal effect of internal strain in dissimilar materials by laser welding, internal strain measurements using high energy synchrotron white X-rays were carried out at BL14B1 in SPring-8. The specimens were dissimilar materials made by laser welding between ferritic/martensitic steel (PNC-FMS) and SUS316 austenitic stainless steel. In this study, we measured the internal strain distribution of three kinds of specimens which changed a laser irradiation condition and it was found that the tensile strain in ferritic/martensitic steel occurred in all specimens before annealing but the residual strain in austenitic stainless steel was not so remarkable. It is thought that these reasons are related to the mechanical characteristic of both the materials. On the other hand, in all specimens after annealing, it was found that the residual strain in both the materials did not almost exist.
Shobu, Takahisa; Zhang, S.*; Shiro, Ayumi; Yamada, Tomonori; Muramatsu, Toshiharu; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Shobu, Takahisa; Shiro, Ayumi; Zhang, S.*; Yamada, Tomonori; Muramatsu, Toshiharu; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
The laser welding method is expected to be applied to the joint between inner and outer ducts for the fast reactor fuel assemblies with inner duct structure. In this study, an anneal effect of the residual stresses in the laser welded steel was investigated using the in-situ strain measurement technique with high energy synchrotron X-rays. We have succeeded in observation of the phenomenon that elastic strain is relaxed before annealing process and the dislocation density gradually decreases thereafter. In addition it was found that the FWHM is a useful parameter for in-situ evaluation of the heat treatment process to effectively optimize the heat treatment condition.
