Development of inspection technology for pipes in high background radiation environments (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; University of Fukui*

JAEA-Review 2025-036, 88 Pages, 2025/11

JAEA-Review-2025-036.pdf:6.36MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2023. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2023, this report summarizes the research results of the "Development of inspection technology for pipes in high background radiation environments" conducted in FY2023. The following two studies are being conducted with the aim of comprehensively developing technologies to address the three needs indicated in the hearing with TEPCO regarding observation of the inside of piping: (1) Hydrogen content, (2) Presence of precipitates, (3) Presence or absence of / radiation emitting nuclides. First, by downsizing existing nondestructive inspection equipment and developing a dedicated radiation detector capable of nondestructively imaging the inside of piping, we aim to obtain information on the inside of piping by nondestructive inspection using lasers, etc., and to clarify the presence or absence of -nuclides in piping and the internal conditions of piping, etc. In addition, we will develop equipment to visualize -nuclides and discriminate -nuclides in high dose rate environments, as well as technology to investigate the contents of the piping. Deployment of the developed technology is expected to be put into practical use by TEPCO and private companies.

Review of JENDL/HE-2007 neutron-induced fission cross sections of uranium-235 and 238 above 200 MeV

Fukahori, Tokio

INDC(JPN)-210 (Internet), 5 Pages, 2023/10

The U(n,f) cross section values were not correctly compiled in the ENDF format, and wrong values are disseminated in the JENDL/HE-2007 file. The high energy part of the U(n,f) cross section for the JENDL/HE-2007 library was evaluated by using the results of the FISCAL code. The correct U(n,f) cross section values of the JENDL/HE-2007 library above 200 MeV is given in this report.

Evaluation of internal strain distribution of dissimilar laser welding using high energy X-rays

Shobu, Takahisa; Shiro, Ayumi*; Muramatsu, Toshiharu*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 9(5), p.318 - 323, 2021/08

https://doi.org/10.18957/rr.9.5.318

Laser welding has already been put into practical use for various metal materials because the irradiation area is very small and the control is easy. In this study, we evaluated strain, stress, deformation, etc. near the processing affected area by high-energy synchrotron radiation X-ray diffraction method, which is one of the problems of laser welding of different materials that are expected to be put into practical use. As a result of internal deformation measurement of the bonding of dissimilar materials of copper and iron, it was confirmed that the copper side with a high coefficient of linear expansion was hardly deformed, strong tensile strain on the iron side, and a plastic deformation region on the heat-affected zone. In addition, a retained austenite phase, which is thought to be caused by the mixture of copper, was observed in the plastic deformation region of iron, and further problems were clarified in the evaluation of material strength in the mixed metallic materials.

A Cubic CeBr gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station

Kaburagi, Masaaki; Shimazoe, Kenji*; Otaka, Yutaka*; Uenomachi, Mizuki*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.

Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08

https://doi.org/10.1016/j.nima.2020.164118

Measurement of high-energy neutron fluxes and spectra around the J-PARC mercury spallation neutron target using multi-foil activation method

Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio

JAEA-Data/Code 2015-033, 28 Pages, 2016/03

JAEA-Data-Code-2015-033.pdf:1.78MB

The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within 30%.

Development of a calculation method for estimating specific energy distribution in complex radiation fields

Sato, Tatsuhiko; Yokoya, Ritsuko; Niita, Koji*

Radiation Protection Dosimetry, 122(1-4), p.41 - 45, 2006/12

https://doi.org/10.1093/rpd/ncl407

Estimation of biological effects due to exposure of HZE particles is one of the key issues in the planning of long-term space missions and heavy ion cancer therapies. Detailed information on the specific energy distributions around their tracks is indispensable in the issue. We therefore calculated the specific energy distributions in liquid water around the tracks of protons and several kinds of heavy ions with energies from 1 MeV/n to 100 GeV/n. The calculations were performed by a Monte Carlo electron track structure simulation code coupled with the Katz's delta-ray production model. An analytical function to reproduce the simulation results has been developed in order to predict the distribution for all kinds of heavy ions with wide energy ranges. By incorporated into the Particle and Heavy Ion Transport code System PHITS, the function enables us to calculate the specific energy distribution in macroscopic matters such as specified organs of astronauts or tumor of patients within a short computational time.

Development of a 100eV, high-flux ion beam acceleration system

Yoshida, Hajime; Yokoyama, Kenji; Suzuki, Satoshi; Enoeda, Mikio; Akiba, Masato

Review of Scientific Instruments, 77(4), p.043502_1 - 043502_4, 2006/04

https://doi.org/10.1063/1.2188459

New beam extraction electrode has been developed for a 100 eV level, high-flux, large irradiation area, and steady-state ion beam source to study about plasma wall interaction in fusion reactors. This electrode has two specific features; one is the structure has sub-millimeter order of spherical multi-aperture triode electrodes and the other is to utilize the plasma sheath for ion acceleration. Obtained ion fluxes ware from 1.51020 H/ms to 5.31020 H/ms with the energy from 28 eV/H to 102 eV/H. These values are comparable to those of conventional high flux ion source in spite of such an extremely low energy.

High flux ion beam acceleration at the 100-eV level for fusion plasma facing material studies

Yoshida, Hajime; Yokoyama, Kenji; Taniguchi, Masaki; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato

Fusion Engineering and Design, 81(1-7), p.361 - 366, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.09.071

A 100 V level, high-flux, large area and steady-state ion beam acceleration has been developed for the investigation of the interactions between fusion edge plasmas and plasma facing materials. We have developed the new electrodes and installed them in the Super Low Energy Ion Source (SLEIS). Obtained hydrogen ion flux is comparable to those of conventional high-flux ion source (1020 H/ms), though the accelerated voltage is extremely low (60-200 eV). This 100 V level ion beam acceleration will be useful to investigate the plasma wall interaction in divertor.

Development and operation of the JAERI superconducting energy recovery linacs

Minehara, Eisuke

Nuclear Instruments and Methods in Physics Research A, 557(1), p.16 - 22, 2006/02

https://doi.org/10.1016/j.nima.2005.10.049

The JAERI FEL facility at Tokai, Ibaraki, Japan has been well known one of the two existing and operating superconducting energy recovery linacs together with one more of JLAB (Jefferson national accelerator facility) FEL facility at Newport News, Virginia, U.S.A. We have independently and successfully developed one of the most advanced and newest accelerator technologies named "superconducting energy recovery linacs (ERLs)" and the application technologies using ERLs in future. We plan to report the current high power FEL upgrade program research, stress corrosion cracking prevention technology research, large current and high brightness photoelectron gun research of negative-electron affinity (NEA) photocathode and NEA electron-excitation cathode as the most important elemental technology in realizing many powerful ERLs.

Radiation safety design for the J-PARC project

Nakashima, Hiroshi; Nakane, Yoshihiro; Masukawa, Fumihiro; Matsuda, Norihiro; Oguri, Tomomi*; Nakano, Hideo*; Sasamoto, Nobuo*; Shibata, Tokushi*; Suzuki, Takenori*; Miura, Taichi*; et al.

Radiation Protection Dosimetry, 115(1-4), p.564 - 568, 2005/12

https://doi.org/10.1093/rpd/nci237

The High Intensity Proton Accelerator Project, named as J-PARC, is in progress, aiming at studies on the latest basic science and the advancing nuclear technology. In the project, the high-energy proton accelerator complex of the world highest intensity is under construction. In order to establish a reasonable shielding design, both simplified and detailed design methods were used in the shielding design of J-PARC. This paper reviews the present status of the radiation safety design study for J-PARC.