Steady-state and transient experiments in mock-up of J-PARC LBE spallation target system using mock-up loop "IMMORTAL"

Obayashi, Hironari; Yamaki, Kenichi; Kita, Satoshi; Yoshimoto, Hidemitsu; Wan, T.; Saito, Shigeru; Sasa, Toshinobu

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.262 - 274, 2019/08

Construction of an experimental facility using LBE spallation target is under planning in the framework of J-PARC project to understand the compatibility of candidate ADS structural materials under flowing high temperature LBE environment with proton / neutron irradiation. We constructed a mock-up test loop, IMMORTAL to verify the feasibility of a primary cooling system in the target system. Including the layout considering remote maintainability, the same design as the actual JAEA's LBE target is reflected in most devices of IMMORTAL such as an electromagnetic pump (EMP), a heat exchanger and instrumentations. During the integrated tests, the individually developed devices of LBE loop system worked without significant malfunction. Several experimental data to verify the safety analysis model for LBE loop system using RELAP5-3D was acquired by simulation experiment of transient events such as beam over power and decrease of forced cooling.

Thermal-hydraulic analysis of the LBE spallation target head in JAEA

Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

Nuclear Technology, 205(1-2), p.188 - 199, 2019/01

https://doi.org/10.1080/00295450.2018.1478591

Flow-accelerated corrosion of type 316L stainless steel caused by turbulent lead-bismuth eutectic flow

Wan, T.; Saito, Shigeru

Metals, 8(8), p.627_1 - 627_22, 2018/08

https://doi.org/10.3390/met8080627

Study on the thermal-hydraulic of TEF-T LBE spallation target in JAEA

Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

Proceedings of 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) (USB Flash Drive), 13 Pages, 2017/09

Effects of grain size on ultrasonic attenuation in type 316L stainless steel

Wan, T.; Naoe, Takashi; Wakui, Takashi; Futakawa, Masatoshi; Obayashi, Hironari; Sasa, Toshinobu

Materials, 10(7), p.753_1 - 753_17, 2017/07

https://doi.org/10.3390/ma10070753

Design of 250kW LBE spallation target for the Japan Proton Accelerator Research Complex (J-PARC)

Sasa, Toshinobu; Saito, Shigeru; Obayashi, Hironari; Sugawara, Takanori; Wan, T.; Yamaguchi, Kazushi*; Yoshimoto, Hidemitsu

NEA/CSNI/R(2017)2 (Internet), p.111 - 116, 2017/06

https://www.oecd-nea.org/science/docs/2017/nsc-r2017-2.pdf

Japan Atomic Energy Agency (JAEA) proposes to reduce the environmental impact caused from high-level radioactive waste by using Accelerator-driven system (ADS). To realize ADS, JAEA plans to build the Transmutation Experimental Facility (TEF) within the framework of J-PARC project. For the JAEA-proposed ADS, lead-bismuth eutectic alloy (LBE) is adopted as a coolant for subcritical core and spallation target. By using TEF in J-PARC, we are planning to solve technical difficulties for LBE utilization by completion of the data for the design of ADS. The 250kW LBE spallation target will be located in TEF facility to prepare material irradiation database. Various R&Ds for important technologies required to build the facilities are investigated such as oxygen content control, instruments development, remote handling techniques for target maintenance, and spallation target design. The large scale LBE loops for 250kW target mock up and material corrosion studies are also manufactured and ready for various experiments. The latest status of 250kW LBE spallation target optimization will be described in the presentation.

Evaluation of globally- & locally-distributed erosion/cavitation damage by using laser ultrasonics

Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

Kashika Joho Gakkai-Shi (USB Flash Drive), 36(Suppl.2), 8 Pages, 2016/10

In-situ structural integrity evaluation for high-power pulsed spallation neutron source by using a laser Doppler method

Wan, T.; Naoe, Takashi; Wakui, Takashi; Haga, Katsuhiro; Kogawa, Hiroyuki; Futakawa, Masatoshi

JAEA-Conf 2015-002, p.76 - 87, 2016/02

https://doi.org/10.11484/jaea-conf-2015-002

High power accelerator driven pulsed spallation neutron sources are being developed in the world. Mercury is used as a target material to produce neutrons via the spallation reaction induced by injected protons. At the moment of the proton injection, the mercury vessel with a double wall structure is impulsively excited by the interaction between mercury and solid wall. The vibrational signals were measured in noncontact and remotely by using a Laser Doppler Vibrometer (LDV) system to evaluate the structure integrity. The extreme damages were assumed as the first step, i.e., the inner structure was partly broken by erosion. The dependency of vibrational behaviors on the damage was systematically investigated through numerical simulations and experiments. A LDV was installed to monitor the dependency of an electro-Magnetic Impact Testing Machine (MIMTM) vibration on the damage size. Through the numerical simulation, it was found that the target vessel vibration depends on the damage size. A technique referred to a Wavelet Differential Analysis (WDA) has been developed to enhance the effect of damages on the impulsive vibration behavior. However, the vibration signals obtained from MIMTM contain considerable noise. In order to reduce the noise effect on the impulsive vibration behavior, the statistical methods referred to an Analysis of Variance (ANOVA) and an Analysis of Covariance (ANCOVA) was applied. Numerical simulation results that obtained from controlling the damage size, were firstly added to random noise with various levels manually, and then were analyzed by the statistic methods. Then, the field data that measured from the real mercury target was analyzed. The results represent that the combination of WDA and ANOVA/ANCOVA could effectively indicate the damage dependency.

TEF beam window design and evaluation of structural integrity

Obayashi, Hironari; Takei, Hayanori; Wan, T.; Kogawa, Hiroyuki; Iwamoto, Hiroki; Sasa, Toshinobu

JPS Conference Proceedings (Internet), 8, p.041002_1 - 041002_7, 2015/09

https://doi.org/10.7566/JPSCP.8.041002

Damage evaluation by impulsive response in structure filled with liquid

Wan, T.; Naoe, Takashi; Wakui, Takashi; Futakawa, Masatoshi; Maekawa, Katsuhiro*

Applied Mechanics and Materials, 566, p.629 - 636, 2014/06

https://doi.org/10.4028/www.scientific.net/AMM.566.629

A double-walled liquid mercury target vessel, which consists of outer and inner walls, is being globally developed for MW-class spallation neutron sources. When proton beams bombard a mercury target, pressure waves are generated due to the rapid thermal heat deposition. These pressure waves trigger impulsive vibrations in the mercury vessel, and cause cavitation damage to the inner wall of the vessel. In this study, the dependency of the vibration behavior of the mercury vessel on the damage is systematically investigated through numerical simulations and experiments, for inner wall damage characterized by hole diameters of 1, 5, 10, 20, and 40 mm. A method referred to as wavelet differential analysis is developed, and a parameter referred to as average intensity is derived for a quantitative damage evaluation. Both the numerical simulation and experimental results show that the average intensity is damage-sensitive and depends on the damage feature size. The critical damage hole diameter is estimated to be 10 mm during damage evaluation.