Potential for remote controllable systematization of the method of testing reinforced concrete using guided-wave on rebar

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.

Recent studies for structural integrity evaluation and defect inspection of J-PARC spallation neutron source target vessel

Wakui, Takashi; Wakai, Eiichi; Naoe, Takashi; Shintaku, Yohei*; Li, T.*; Murakami, Kazuya*; Kanomata, Kenichi*; Kogawa, Hiroyuki; Haga, Katsuhiro; Takada, Hiroshi; et al.

Journal of Nuclear Materials, 506, p.3 - 11, 2018/08

https://doi.org/10.1016/j.jnucmat.2018.02.030

The mercury target vessel is designed as multi-walled structure with thin wall (min. 3 mm), and assembled by welding. In order to estimate the structural integrity of the vessel, it is important to measure the defects in welding accurately. For nondestructive tests of the welding, radiographic testing is applicable but it is difficult to detect for some defect shapes. Therefore it is effective to do ultrasonic testing together with it. Because ultrasonic methods prescribed in JIS inspect on the plate with more than 6 mm in thickness, these methods couldn't be applied as the inspection on the vessel with thin walls. In order to develop effective method, we carried out measurements using some testing method on samples with small defect whose size is specified. In the case of the latest phased array method, measured value agreed with actual size. It was found that this method was applicable to detect defects in the thin-walled structure for which accurate inspection was difficult so far.

Development of delayed gamma-ray spectroscopy for nuclear material analysis

Rodriguez, D.; Rossi, F.; Takahashi, Tone; Seya, Michio; Koizumi, Mitsuo; Crochemore, J. M.*; Varasano, G.*; Bogucarska, T.*; Abbas, K.*; Pedersen, B.*

Proceedings of INMM 59th Annual Meeting (Internet), 7 Pages, 2018/07

Ultrasonic guided wave approach for inspecting concave surface of the laser butt-welded pipe

Furusawa, Akinori; Nishimura, Akihiko; Takebe, Toshihiko*; Nakamura, Masaki*; Takenaka, Yusuke*; Saijo, Shingo*; Nakamoto, Hiroyuki*

E-Journal of Advanced Maintenance (Internet), 9(2), p.44 - 51, 2017/08

http://www.jsm.or.jp/ejam/Vol.9No.2/AA/AA127/AA127.html

The aim of this work is to investigate the applicability of ultrasonic guided wave for evaluation of laser beam butt-welding quality. Ten in total test pipes having welding seam is prepared. Two piece of pipe are jointed and continuous laser beam is irradiated on the edges, varying laser irradiation power, welding side and surface profile of the adjacent edges of the pipe. Ultrasonic guided wave testing experiment is performed on the pipes. Torsional mode guided wave is excited by EMAT. The experimental results are analyzed and issues are discussed. The reflection wave bullet from the poor interface of the welding seam is clearly observed, whereas no reflection from fine welded line. From the aspect of laser irradiation power, welding side and surface profile of the adjacent edges, the relation between the interface condition and detection wave bullet are analyzed. It is found that the ultrasonic guided wave technologies have the potential for evaluating laser beam butt-welding seam.

Application of probability generating function to the essentials of nondestructive nuclear materials assay system using neutron correlation

Hosoma, Takashi

JAEA-Research 2016-019, 53 Pages, 2017/01

JAEA-Research-2016-019.pdf:5.71MB

Application of probability generating function for nondestructive nuclear materials assay system was studied. First, high-order neutron correlations were derived algebraically up to septuplet and basic characteristics of the correlations were investigated. It was found that higher-order correlation increases rapidly in response to the increase of leakage multiplication, crosses and leaves lower-order correlations behind, when leakage multiplication is 1.3 that depends on detector efficiency and counter setting. Next, fission rates and doubles count rates by fast neutron and by thermal neutron in their coexisting system were derived algebraically. It was found that the number of induced fissions per unit time by fast neutron and by thermal neutron, the number of induced fissions ( 1) by one source neutron, and individual doubles count rates were possible to be estimated from Rossi-alpha combined distribution and measured ratio of each area obtained by differential die-away self-interrogation and conventional assay data.

JAEA's contribution for R&D and human resource development on implementing IAEA safeguards

Naoi, Yosuke; Oda, Tetsuzo; Tomikawa, Hirofumi

Nihon Genshiryoku Gakkai-Shi ATOMO, 58(9), p.536 - 541, 2016/09

Japan has been promoting nuclear energy research and development, and the use of nuclear energy for only peaceful purposes in accordance with Atomic Energy Basic Acts enacted in 1955. In order to ensure limited to their peaceful utilization, it has been performing a nuclear material accountancy and reporting it based on bilateral nuclear agreement (Japan and the United States, Japan and France, Japan and Canada and so on) before concluding the comprehensive safeguards agreement with the IAEA. After the conclusion of that in 1977, the Japanese national law had been revised. The nuclear material accountancy and its reports to the IAEA have been implemented based on the revised law. In 1999, Japan ratified the additional protocol. Then it has been responding a new obligation in the additional protocol. The correctness and completeness of the declaration of nuclear activities in Japan have been verified by the IAEA, and then the "broader conclusion" was given to Japan in 2004. There indicates no diversion or undeclared nuclear activities in Japan. Since then Japan has been obtaining the "broader conclusion" every year. In this report we will report the JAEA's contribution to the IAEA safeguards on technical research and development and human resource development.

The States of the art of the nondestructive assay of spent nuclear fuel assemblies; A Critical review of the Spent Fuel NDA Project of the U.S. Department of Energy's Next Generation Safeguards Initiative

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.

Essentials of neutron multiplicity counting mathematics; An Example of U-Pu mixed dioxide

Hosoma, Takashi

JAEA-Research 2015-009, 162 Pages, 2015/08

JAEA-Research-2015-009.pdf:22.3MB

Neutron coincidence counting assay systems have been developed in the last two decades. Objects would extend to high-mass uranium-plutonium dioxide containing other spontaneous fission nuclei, so essentials of neutron multiplicity counting were reconsidered and expanded: (a) Formulae of multiplicity distribution were algebraically derived up to septuplet using a probability generating function; (b) Leakage multiplication was evaluated not by Monte Carlo method but by an average length from an arbitrary point inside a sample to an arbitrary point on its surface and a probability of induced fission within the length; (c) Mechanism of coincidence counting was associated with a couple of different time axes in Poisson process, and consequently a pair of close-to-coincident neutrons from the process was derived. For the formulae, new expressions using combination were wrote down. For spectrum and mean free path, actually treated uranium-plutonium dioxide was selected as an example.

Visualization of internal structures of reactor core in the HTTR by cosmic-ray muon radiography; Non-destructive inspection of internal structures of reactor core

Takamatsu, Kuniyoshi

Nihon Genshiryoku Gakkai-Shi ATOMO, 57(6), p.389 - 393, 2015/06

JP, 2010-166333   Licensable Patent Information Database   Patent publication (In Japanese)

In our study, we focused on a nondestructive inspection method by cosmic-ray muons which could be used to observe the internal reactor from outside the RPV and the CV. We conducted an observation test on the HTTR to evaluate the applicability of the method to the internal visualization of a reactor. We also analytically evaluated the resolution of existing muon telescopes to assess their suitability for the HTTR observation, and were able to detect the major structures of the HTTR based on the distribution of the surface densities calculated from the coincidences measured by the telescopes. Our findings suggested that existing muon telescopes could be used for muon observation of the internal reactor from outside the RPV and CV.

Introduction to development of advanced safeguards and security NDA technologies by JAEA-ISCN

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/BO 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.