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field using new type of nuclear emulsionKawarabayashi, Jun*; Ishihara, Kohei*; Takagi, Keisuke*; Tomita, Hideki*; Iguchi, Tetsuo*; Naka, Tatsuhiro*; Morishima, Kunihiro*; Maeda, Shigetaka
Journal of ASTM International (Internet), 9(3), 5 Pages, 2012/03
In order to measure the neutron from a spent fuel assembly in fast breeder reactor precisely, we made new nuclear emulsion based on non-sensitized OPERA film with AgBr grain size of 60, 90 and 160 nm. The efficiency for 
Cf neutron of the new emulsion was calculated to be 0.7
10
which energy ranged from 0.3 to 2 MeV that agrees with preliminary estimated value from experimental results. The sensitivity of the new emulsion was also estimated experimentally by irradiating 565 KeV and 14 MeV neutrons and found that the emulsion with the AgBr grain size of 60 nm showed the lowest sensitivity among these three emulsions but still had enough sensitivity for proton. Also, there was a suggestion from the experimental data that there was a threshold LET of 15 KeV/
m for our new emulsion below which no silver cluster was developed. Further development of the response of nuclear emulsion with a few tens of nano-meter AgBr size is next step of this study.
Kondo, Keietsu; Miwa, Yukio; Tsukada, Takashi; Yamashita, Shinichiro; Nishinoiri, Kenji
Journal of ASTM International (Internet), 7(1), p.220 - 237, 2010/01
no abstracts in English
Nishiyama, Yutaka; Yamaguchi, Masatake; Onizawa, Kunio; Iwase, Akihiro*; Matsuzawa, Hiroshi*
Journal of ASTM International (Internet), 6(7), 8 Pages, 2009/07
A study on grain-boundary segregation and embrittlement in terms of the Charpy ductile-to-brittle transition temperature (DBTT) has been performed for the neutron-irradiated A533B steels with a typical contents of impurities of Japanese reactor pressure vessel ones. The neutron irradiation was conducted at 563K to a fluence of 1.3 10
n/m
(E
1MeV) using Materials Testing Reactors. The neutron irradiation induced the phosphorus (P) and nickel (Ni) segregation and the reduction of segregated carbon (C) in some cases at grain-boundaries. The increase in the P segregation at high fluences (5 10
n/m, E1MeV) was less than 0.15 in monolayer coverage for the steels with the bulk content of P not exceeding 0.02 wt.%. The hardening more strongly affected the DBTT shift than the P segregation for those steels. The reduction of segregated C that enhances the grain-boundary cohesion by neutron fluence is not large enough to cause the DBTT shift.
Tanigawa, Hiroyasu; Sokolov, M. A.*; Sawahata, Atsushi*; Hashimoto, Naoyuki*; Ando, Masami; Shiba, Kiyoyuki; Enomoto, Masato*; Klueh, R. L.*
Journal of ASTM International (Internet), 6(5), 10 Pages, 2009/05
The master curve (MC) method works when the transition fracture toughness values follow the MC, and once the value is scaled properly, the MC is usually independent of the type of steel or the type of test specimen. This method is very much depending on the assumption that the fracture initiation points are homogeneously distributed and its initiation mechanism is independent on test temperature. The reduced-activation ferritic/martensitic steels (RAFs), such as F82H (Fe-8Cr-2W-0.2V-0.04Ta), has Al
O
Ta(V,Ti)O composite inclusions, or simple Ta(V)O inclusions, and shows inhomogeneous distribution, and it was revealed that that RAFs which contain Ta could initiate the facture in the different mechanism at lower temperature as the composite inclusions become fragile, and this should be considered when the toughness measured with small size toughness specimen which is usually tested at lower temperature.
Kim, S.-W.*; Tanigawa, Hiroyasu; Hirose, Takanori; Koyama, Akira*
Journal of ASTM International (Internet), 5(8), 8 Pages, 2008/09
Depending on the pulse lengths, the operating conditions, and the thermal conductivity, oscillating temperature gradients will cause elastic and elastic-plastic cyclic deformation giving rise to (creep-) fatigue in the structural first wall and blanket components. Small specimen testing technology and related remote-control testing techniques are indispensable for the effective use of the limited volumes of materials test reactor and proposed intense neutron sources. In order to perform an accurate fatigue lifetime assessment using small specimen, the effects of material factors (surface morphology, inclusion, etc.) on low cycle fatigue (LCF) is mandatory. In this work, the LCF properties of F82H IEA heat were examined for three kinds of surface morphology with miniaturized hourglass-type fatigue specimens (SF-1), and the correlation between LCF crack initiation/propagation and distribution of inclusions also revealed by using SF-1 specimen. Fracture surfaces and crack initiation sites were investigated by SEM.
Nishiyama, Yutaka; Onizawa, Kunio; Suzuki, Masahide
Journal of ASTM International (Internet), 4(8), 12 Pages, 2007/09
no abstracts in English
Maeda, Shigetaka; Wootan, D. W.; Sekine, Takashi
Journal of ASTM International (Internet), 3(8), 9 Pages, 2006/09
An extensive set of neutron dosimeters ranging from the core center to beyond the reactor vessel were irradiated during the first two operating cycles of the MK-III core to allow a detailed characterization of the neutron spectra and flux distributions for this new core configuration. New analysis methods for predicting the reaction rates for comparison with the dosimetry measurements based on the MCNP code were developed. Analysis of previous MK-II cycle 34-35 dosimetry tests was used to verify the methods. Core models were developed for the different types and locations of dosimetry test assemblies and biasing schemes were developed. MCNP optimization techniques and the C/E differences were explored. Most of the important parameters that affect the reaction rate calculations and measurements were investigated.
