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Nagatani, Taketeru; Sagara, Hiroshi*; Kosuge, Yoshihiro*; Nomi, Takayoshi; Okumura, Keisuke
Journal of Nuclear Science and Technology, 13 Pages, 2022/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Koizumi, Mitsuo
Proceedings of 41st ESARDA Annual Meeting (Internet), p.260 - 267, 2019/05
Furusawa, Akinori; Nishimura, Akihiko; Takenaka, Yusuke; Muramatsu, Toshiharu
Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05
The aim of this work presented here is to demonstrate the potential of our method for remote controllable systematization, of testing reinforced concrete based on ultrasonic guided-wave on rebar. In order to investigate how the deteriorated phenomena has the effects on the ultrasonic guided-wave propagating on the rebar, following experiments are conducted. Test pieces used for the experiments are made of bare steel rod and cylindrically pored mortar to be representing the actual reinforced concrete. Irradiating the end face of the rod with nanosecond pulsed laser makes the ultrasonic guided-wave induced, at the other end face, the guided wave signal is measured with ultrasonic receiver. One test piece is with no damage and the other is deteriorated test piece. The deterioration is made by electrolytic corroded method. The guided-wave signal from the deteriorated test piece is measured with respect to each energization time, the change in the waveform is investigated. Analyzing the results from the experiments above, it is found that the deterioration of rebar has remarkable effects on the guided-wave signal. The signal from test piece with no damage has strong peak at both specific frequency and lower region, on the other hand, signals from deteriorated test piece has only at the specific frequency depending on the diameter of the steel rod. Finally, discussion concerning with the experimental results and future perspective for remote controllable systematization of our method is carried out.
Okumura, Keisuke; Riyana, E. S.
JAEA-Conf 2018-001, p.63 - 68, 2018/12
The decommissioning of the Fukushima Daiichi Nuclear Power Station (1F) is an unexplored field. Although the investigations for inside primary containment vessel (PCV) by robots have been underway by IRID, actual situation inside the PCV and the characteristics of fuel debris have not been sufficiently clarified yet. Under such circumstances, the computational simulation with reliable data is an effective means for solving many problems for the 1F decommissioning. Here, as application examples using nuclear data such as JENDL-4.0, we will introduce some researches and developments on (1) prediction of dose rate distribution in PCV, (2) remotely operated vehicle (ROV) system to explore submerged fuel debris in PCV, (3) non-destructive assay of nuclear fuel materials in a fuel debris canister.
Komeda, Masao; Ozu, Akira; Mori, Takamasa; Nakatsuka, Yoshiaki; Maeda, Makoto; Kureta, Masatoshi; Toh, Yosuke
Journal of Nuclear Science and Technology, 54(11), p.1233 - 1239, 2017/11
Times Cited Count：7 Percentile：62.15(Nuclear Science & Technology)The previous active neutron method cannot remove the influence of the multiplication effect of neutrons produced by second- and subsequent fission reactions, and it might overestimate the amount of nuclear material if an item contains large amounts. In this paper, we discussed the correction method for the neutron multiplication effect on the measured data in the fast neutron direct interrogation (FNDI) method, one of the active neutron methods, supposing that the neutron multiplication effect is caused mainly by third-generation neutrons from the second-fission reactions under the condition that the forth-generation neutrons are much fewer. This paper proposed a correction method for the neutron multiplication effect in the measured data. Moreover we have shown a possibility that this correction method gives rough estimates of the effective neutron multiplication factor and the subcriticality.
Seya, Michio; Hajima, Ryoichi*; Kureta, Masatoshi
Proceedings of INMM 58th Annual Meeting (Internet), 10 Pages, 2017/07
Large size freight cargo containers are the most vulnerable items from nuclear security points of view because of their large volume and weight of cargo inside for hiding heavily shielded objects. For strengthening nuclear security, secure detection of NMs in heavily shielded objects, and safe handling (dismantlement) of detected (suspicious) objects, are essential. These require secure detection of NMs, inspection of detailed interior structures of detected objects, rough characterization of NMs (for nuclear bomb or RDD etc.) and confirmation of existence of explosives etc. By using information obtained by these inspections, safe dismantlement of objects is possible. In this paper, we propose a combination of X-ray scanning system with NRF-based NDD system using monochromatic 
-ray beam for a secure detection and interior inspections. We also we propose active neutron NDA system using a DT source for interior inspection of NM part.
Kitazawa, Sin-iti*; Wakai, Eiichi; Aoto, Kazumi
Radiation Physics and Chemistry, 127, p.264 - 268, 2016/10
Times Cited Count：4 Percentile：31.38(Chemistry, Physical)The effects of annealing and double ion irradiation on nuclear structural materials were investigated using a novel, non-destructive, non-contact diagnostic method. A laser-induced and laser-detected surface acoustic wave (SAW) was adopted as a diagnostic system. The SAWs propagation velocity and the SAWs vibration velocity along the normal direction of the surface were measured to investigate mechanical properties of the substrates. Change of the shear modulus was detected in the annealed substrates. Non-linear effect on amplitude of the excited SAW was observed on the double ion irradiated materials. The potential of the SAW diagnostic system for assessing nuclear structural materials was demonstrated.
Bolind, A. M.*; Seya, Michio
JAEA-Review 2015-027, 233 Pages, 2015/12
JAEA-Review-2015-027.pdf:30.21MB
This report surveys the 14 advanced NDA techniques that were examined by the Spent Fuel NDA Project of the Next Generation Safeguards Initiative (NGSI) of the U.S. DOE-NNSA. It discusses and critique NDA techniques from a view point of obtaining higher accuracies. The report shows the main problem, large uncertainties in the assay results are caused primarily by using too few independent NDAs. In this report authors shows that at least three independent NDA techniques are required for obtaining better accuracies, since the physics of the NDA of SFAs is three dimensional.
Tsuchiya, Harufumi; Koizumi, Mitsuo; Kitatani, Fumito; Kureta, Masatoshi; Harada, Hideo; Seya, Michio; Heyse, J.*; Kopecky, S.*; Mondelaers, W.*; Paradela, C.*; et al.
Proceedings of 37th ESARDA Annual Meeting (Internet), p.846 - 851, 2015/08
One of non-destructive techniques using neutron resonance reaction is neutron resonance transmission analysis (NRTA). We are presently developing a new active neutron non-destructive method including NRTA in order to detect and quantify special nuclear materials (SNMs) in nuclear fuels containing MA. We aim at applying the technique to not only particle-like debris but also other materials in high radiation field. For this aim, we make use of fruitful knowledge of neutron resonance densitometry (NRD) that was developed for particle-like debris in melted fuel. NRTA detects and quantifies SNMs by means of analyzing a neutron transmission spectrum via a resonance shape analysis. In this presentation, we explain the basic of NRTA and its role in the active neutron technique. Then, with knowledge obtained in the development of NRD, we discuss items to be investigated for NRTA in our active neutron technique.
Seya, Michio; Kureta, Masatoshi; Soyama, Kazuhiko; Nakamura, Hironobu; Harada, Hideo; Hajima, Ryoichi
Proceedings of INMM 55th Annual Meeting (Internet), 10 Pages, 2014/07
JAEA has been implementing development programs of basic technologies of the following advanced NDA (non-destructive assay) of nuclear material (NM) for nuclear safeguards and security. (1) Alternative to 
He neutron detection using ZnS/B
O
ceramic scintillator, (2) NRD (neutron resonance densitometry) using NRTA (neutron resonance transmission analysis) and NRCA (neutron resonance capture analysis), (3) NRF (nuclear resonance fluorescence)-NDA using laser Compton scattered (LCS) -rays (intense mono-energetic -rays). The development program (1) is for NDA systems that use ZnS/BO ceramic scintillator as alternative neutron detector to He for coming shortage of its supply. The program (2) is for a NDA system of isotopic composition measurement (non-destructive mass spectroscopy) in targets such as particle-like melted fuel debris using NRTA and NRCA. The program (3) is for NDA systems using a specific NRF reaction of certain Pu/U isotope caused by mono-energetic LCS -ray with energy tuned to the specific excited state of the isotope. This paper introduces above three programs.
Sawa, Kazuhiro; Ueta, Shohei; Shibata, Taiju; Sumita, Junya; Ohashi, Jumpei; Tochio, Daisuke
JAERI-Tech 2005-024, 34 Pages, 2005/03
JAERI-Tech-2005-024.pdf:2.15MB
The Very-High-Temperature Reactor (VHTR) is one of the strong candidates for the Generation IV Nuclear Energy System. JAERI has developed Zirconium carbide (ZrC)-coated fuel particle and ZrC coating layer is expected to maintain its intactness under higher temperature and burn-up comparing conventional SiC-coating layer. JAERI carries out (1) ZrC-coating process development by large-scale coater, (2) inspection method development and (3) irradiation test and post irradiation experiment of ZrC coated particles. Also, JAERI carries out reactivity insertion tests to clarify the coating failure mechanism and tries to increase allowable temperature limit in case of reactivity insertion accident. Furthermore, JAERI develops non-destructive evaluation methods for mechanical properties of graphite components by ultrasonic testing and micro-indentation technique. This report describes these research and development plan and results of FY 2004 as a MEXT contact research.
Onizawa, Kunio; Shibata, Katsuyuki; Kato, Daisuke*; Li, Y.*
JSME International Journal, Series A, 47(3), p.486 - 493, 2004/07
The probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed in JAERI. This code can evaluate the conditional probabilities of crack initiation and fracture of a reactor pressure vessel (RPV) under transient conditions such as pressurized thermal shock (PTS). Based on the temperature and stress distributions in the vessel wall for four PTS sequences in a typical 3-loop PWR, parametric PFM analyses are performed using PASCAL on the variables such as pre-service inspection model, crack geometry, fracture toughness curve and irradiation embrittlement prediction equation. The results showed that the good perfomance inspection model had a significant effect on the fracture probability and reduced it by more than 3 orders of magnitude. The fracture probability calculated by the fracture toughness estimation method in Japan was about 2 orders of magnitude lower than that by the USA method. It was found that the treatment of a semi-elliptical crack in PASCAL reduced the conservatism in a conventional method that it is transformed into an infinite length crack.
Nakahira, Masataka
Journal of Nuclear Science and Technology, 40(9), p.687 - 694, 2003/09
Times Cited Count：3 Percentile：26.24(Nuclear Science & Technology)The ITER vacuum vessel is a double-walled torus with large-sized quadrilateral ports and is required to provide a quite high degree of vacuum for deutrium - tritium fusion reaction. The vacuum vessel is required to install after assembled with toroidal field coils. From a radiological safety aspect, the vacuum vessel is functioned as a physical barrier to enclose radioactive materials. Therefore, construction of the vacuum vessel needs application of newly developed technologies on design, fabrication and examination. The technologies include design approach by finite element analysis, and partial penetration T welded joints to join ribs to outer shell. Several issues have to be resolved for applying those technologies to the vacuum vessel. This paper describes several newly developed technologies and key issues for applying to the vacuum vessel and then their resolutions.
Ezato, Koichiro; Dairaku, Masayuki; Taniguchi, Masaki; Sato, Kazuyoshi; Akiba, Masato
Journal of Nuclear Materials, 307-311(Part1), p.144 - 148, 2002/12
Times Cited Count：14 Percentile：66.48(Materials Science, Multidisciplinary)no abstracts in English
Kosaku, Yasuo; Kuroda, Toshimasa*; Enoeda, Mikio; Hatano, Toshihisa; Sato, Satoshi; Akiba, Masato
JAERI-Tech 2002-063, 98 Pages, 2002/07
JAERI-Tech-2002-063.pdf:11.16MB
no abstracts in English
Ezato, Koichiro; Taniguchi, Masaki; Sato, Kazuyoshi; Araki, Masanori; Akiba, Masato
Physica Scripta, T91, p.110 - 112, 2001/07
Times Cited Count：2 Percentile：20.99(Physics, Multidisciplinary)no abstracts in English
Oka, Kiyoshi; *; *; *; Takahashi, Hiroyuki*; Tada, Eisuke
JAERI-Tech 99-048, 222 Pages, 1999/07
no abstracts in English
Koizumi, Koichi; Oka, Kiyoshi; Tada, Eisuke
Dai-8-Kai MAGDA Konfarensu Koen Rombunshu, p.252 - 255, 1999/00
no abstracts in English
J.T.Lindsay*; Fujine, Shigenori*; Mishima, Kaichiro*; Hibiki, Takashi*; Yoneda, Kenji*; *; Matsubayashi, Masahito; M.N.Islam*
Fifth World Conf. on Neutron Radiography, 0, p.571 - 577, 1996/00
no abstracts in English
Nakajima, Ken; ; Suzaki, Takenori
Nuclear Science and Engineering, 119, p.175 - 181, 1995/00
Times Cited Count：6 Percentile：55.41(Nuclear Science & Technology)no abstracts in English
