The status of the Japanese material properties handbook and the challenge to facilitate structural design criteria for DEMO in-vessel components

Nozawa, Takashi; Tanigawa, Hiroyasu; Kojima, Takaki; Itoh, Takamoto; Hiyoshi, Noritake; Ohata, Mitsuru; Kato, Taichiro; Ando, Masami; Nakajima, Mio; Hirose, Takanori; Reed, Jordan; Chen, Xiang; Geringer, Josina W.; Katoh, Yutai

doi:10.1088/1741-4326/ac269f

Cited by 20 publications

(3 citation statements)

References 20 publications

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“…The main components are the blanket segment which is a component with several blanket modules fixed in the back plate, divertor cassettes and VV and superconducting coils. The blanket structure is manufactured using the reduced-activation martensitic steel (F82H) [8], which T breeder and neutron multiplier are Li 2 TiO 3 [9] and Be 12 Ti [10], respectively. The divertor plate consists of the W monoblock and F82H cooling tubes and substrates.…”

Section: Specification Of Ja Demomentioning

confidence: 99%

Development of water-cooled cylindrical blanket in JA DEMO

Youji,

Hiroyasu,

Yoshiteru

2024

Nucl. Fusion

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The concept of the tritium breeding blanket for Japan’s DEMOnstration fusion reactor (JA DEMO) has been developed with pressure tightness against in-box Loss-of-coolant accidents based on a water-cooled solid breeder concept. The cooling conditions are designed on the PWR (pressurized-water reactor) water conditions which are the coolant temperature of 290 ºC - 325 ºC and the operating pressure of 15.5 MPa, respectively. The point of the blanket design is to reduce the amount of structural material in casing as well as to ensure its pressure tightness. This is because a decrease in the amount of structural material improves TBR (Tritium Breeding Ratio). A cylindrical structure, a thin wall casing structure which ensures pressure tightness and could increase TBR, is feasible. However, a relatively larger useless space is expected between modules when the cylindrical blanket modules are arranged in a vacuum vessel, which could decrease TBR. Therefore, the cylindrical blanket modules are to be in a close-packed arrangement to reduce useless space. The Be12Ti block (which shows a minor swelling compared to Be) is selected to achieve the target TBR as the net Be density is equivalent to the case of the Be pebble. The use of Be12Ti blocks can reduce or remove the cooling piping inside the module as the Be12Ti block has a higher thermal conductivity than pebbles. As a result of the neutronics, Finite element method, and Computational Fluid Dynamics analyses, it was found that the target TBR value can be achieved in cylindrical structure blanket that ensure pressure tightness.

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Section: Specification Of Ja Demomentioning

confidence: 99%

Development of water-cooled cylindrical blanket in JA DEMO

Youji,

Hiroyasu,

Yoshiteru

2024

Nucl. Fusion

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“…For metallic materials like F82H, a multilinear isotropic plastic hardening model was applied, which considers both large deformations and geometric nonlinear deformations. Young's modulus and Poisson's ratio were incorporated into the data at room temperature [34]. The iFEM analysis described above was used to obtain the true stress-true strain curve of the F82H material.…”

Section: Inverse Femmentioning

confidence: 99%

Real-time measurement of minimum cross-sectional area and radius of curvature of miniature plate specimens using a high-speed laser profiler for calculating true stress-true strain curves

Kato

Ruan

Nozawa

2023

Meas. Sci. Technol.

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True stress-true strain curves are fundamental for designing and analyzing structures such as fusion reactors. These curves are typically obtained by conducting tensile tests on round bar specimens. However, due to material dimension limitations, plate specimens are sometimes used instead of round bar specimens. Obtaining true stress-true strain curves experimentally from plate specimens can be challenging. To address this challenge, this study aims to obtain true stress-true strain curves of miniature plate specimens using both analytical and experimental methods. The analytical method involved inverse finite element analysis, while the experimental method utilized real-time measurement of the minimum cross-sectional area and radius of curvature of a miniature plate specimen with a high-speed laser profiler. Comparing the true stresses obtained from the analytical and experimental methods, we found that the difference was typically within 5%. These findings suggest that inverse finite element analysis and laser profilometry are effective methods for determining the true stress-true strain of miniature plate specimens.

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“…Among the several possible designs of the cooling tubes, their most significant difference from the heat exchanger tubes of the PWR-SGs from the viewpoint of ECT is that they are made of F82H reduced activation ferritic/martensitic steel [7][8][9]. This is because ECT becomes insensitive when it is applied to magnetic materials in general [10].…”

Section: Introductionmentioning

confidence: 99%

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

KAKO

Tomizawa

et al. 2022

Plasma and Fusion Research

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This study investigated the applicability of eddy current testing (ECT) to the non-destructive inspection of cooling tubes in the blanket of a fusion DEMO reactor. Pipes made of F82H steel with inner and outer diameters of 9.0 and 11.0 mm, respectively, were prepared, and slits imitating cracks were fabricated on the pipe surfaces. ECT was performed using a differential type bobbin probe having one exciting and two detecting coils designed in this study. The results of the inspections and subsequent three-dimensional finite element simulations revealed that a bobbin probe is effective in detecting cracks appearing on the inner surface of a pipe. Moreover, the detectability does not deteriorate significantly when cracks oriented in the circumferential directions are targeted, unlike in the case of ECT of the heat exchanger tubes of the steam generators of the pressurized water reactors. This indicates that a probe with a more complicated structure, such as a plus-point probe, would be unnecessary to detect flaws on the inner surface of a pipe. In contrast, the ECT signals from a non-penetrating slit on the outer surface were buried in noise even though the slit was as deep as 0.9 mm.

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The status of the Japanese material properties handbook and the challenge to facilitate structural design criteria for DEMO in-vessel components

Cited by 20 publications

References 20 publications

Development of water-cooled cylindrical blanket in JA DEMO

Development of water-cooled cylindrical blanket in JA DEMO

Real-time measurement of minimum cross-sectional area and radius of curvature of miniature plate specimens using a high-speed laser profiler for calculating true stress-true strain curves

Probe Design for the Eddy Current Inspection of Cooling Tubes in the Blanket of a Fusion DEMO Reactor

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