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.

An Approach for remote nondestructive testing method for concrete structure using laser-generated ultrasonic

Furusawa, Akinori; Nishimura, Akihiko; Takenaka, Yusuke*; Nakamura, Kaori*

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 6 Pages, 2017/00

http://hotlab.sckcen.be/proceedings

Testing of concrete structures in NPPs is needed to guarantee hereafter workability. Recent work says Core Concrete Reaction advances erosion of the concrete structures of Fukushima NPPs and it's difficult to estimate the correct depth of CCR. In addition, it is clear that seawater intrusion makes the rebar in the concrete structures corroded, thus, advanced remote testing methods for the deterioration should be considered. Gap or decrease of the adhesiveness between rebar and outer concrete appears in its deterioration process. We had a sense of possibility introducing a new testing method based on that. The concept is to propagate laser-excited ultrasonic gathering the information about the deterioration inside and received at distance with LDV. In this work, we investigate and report how it has the effect on propagating ultrasonic along the rebar to decrease adhesiveness between the rebar and the concrete experimentally.