Prediction of J-Integrals at Defects in W-9CR Steel Sandwich-Type Cooling Pipes

Abstract Sandwich-type cooling pipes of the first wall of future fusion nuclear reactors (i.e. DEMO) will likely consist of tungsten brazed to a Reduced Activation Ferritic Martensitic (RAFM) steel. Under a high heat flux (HHF) (1–5 MW/m2) the mismatch in thermal expansion between tungsten and steel results in significant thermal stresses in the brazing region. These stresses can cause crack initiation and growth and thus compromise the structural integrity of such pipes. Finite element analyses have been performed on the brazed joints of a reference cooling assembly under HHF. Thermal stresses and resulting plastic strains were estimated for both the braze interlayer and parent materials. As images of brazed joints revealed, brazing processes are very likely to induce defects near the edges of the joints. A crack is therefore introduced in the brazed region where simulated stresses and strains are found to be the highest. J-integrals were calculated for cracks growing from an edge to the center of the considered piping assembly. The results are discussed in relation to the current sandwich-type piping design of the DEMO reactor.

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CFD Application to Subcooled Boiling Analyses on the First Wall of WCCB Blanket for CFETR

Volume 8: Computational Fluid Dynamics (CFD) and Coupled Codes; Nuclear Education, Public Acceptance and Related Issues ◽

10.1115/icone25-66216 ◽

2017 ◽

Author(s):

Kecheng Jiang ◽

Xuebin Ma ◽

Songlin Liu

Keyword(s):

Heat Flux ◽

Structural Integrity ◽

Volume Fraction ◽

Flow Boiling ◽

High Heat ◽

High Heat Flux ◽

First Wall ◽

Subcooled Flow Boiling ◽

Square Channel ◽

Cfd Method

In this paper, by using the CFD method, the efforts have been tried to conduct the investigation on the subcooled flow boiling in the first wall channel of Water cooled ceramic breeder (WCCB) blanket for CFETR. The detailed 3D distribution of temperature and vapor in the flowing passage have been presented under the heat flux of 0.5MW/m2 and 1MW/m2, respectively. Due to the high heat flux from plasma, the vapor distribution in the channel decreases from the plasma side to the breeder side along the radial direction. Undoubtedly, the volume fraction of vapor increases along the flowing direction because of the heating. Besides, the distribution of the channel wall along the toroidal direction presents the U-shaped tendency. As demonstrated by the results, the vapor is more likely to be generated at the corner of the square channel, and this can easily cause the Critical Heat Flux (CHF), which will destroy the structural integrity and materials melting. To avoid the enrichment of vapor in the corner, the optimization on the flowing channel has been performed by smoothing the corner. The results show that the volume fraction of vapor can be effectively decreased compared with the original square channel. Moreover, from the perspective of thermal hydraulics, the circular tube is the optimized channel which can not only avoid the concentration of vapor, but also can decrease the peak volume fraction.

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Thermo-Fluid-Stress-Deformation Analysis of Two-Layer Microchannels for Cooling Chips With Hot Spots

Journal of Electronic Packaging ◽

10.1115/1.4030005 ◽

2015 ◽

Vol 137 (3) ◽

Cited By ~ 4

Author(s):

Abas Abdoli ◽

George S. Dulikravich ◽

Genesis Vasquez ◽

Siavash Rastkar

Keyword(s):

Heat Flux ◽

Thermal Stresses ◽

Hot Spot ◽

Heat Removal ◽

High Heat ◽

Heat Transfer Analysis ◽

Deformation Analysis ◽

High Heat Flux ◽

Cooling Design ◽

Microchannel Cooling

Two-layer single phase flow microchannels were studied for cooling of electronic chips with a hot spot. A chip with 2.45 × 2.45 mm footprint and a hot spot of 0.5 × 0.5 mm in its center was studied in this research. Two different cases were simulated in which heat fluxes of 1500 W cm−2 and 2000 W cm−2 were applied at the hot spot. Heat flux of 1000 W cm−2 was applied on the rest of the chip. Each microchannel layer had 20 channels with an aspect ratio of 4:1. Direction of the second microchannel layer was rotated 90 deg with respect to the first layer. Fully three-dimensional (3D) conjugate heat transfer analysis was performed to study the heat removal capacity of the proposed two-layer microchannel cooling design for high heat flux chips. In the next step, a linear stress analysis was performed to investigate the effects of thermal stresses applied to the microchannel cooling design due to variations of temperature field. Results showed that two-layer microchannel configuration was capable of removing heat from high heat flux chips with a hot spot.

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Post-mortem analysis of HIP bonded first wall panel made of SS316 and DS-Cu after high heat flux testing

Fusion Technology 1996 ◽

10.1016/b978-0-444-82762-3.50098-7 ◽

1997 ◽

pp. 511-514 ◽

Cited By ~ 1

Author(s):

Toshihisa Hatano ◽

Kiyoshi Fukaya ◽

Masayuki Dairaku ◽

Toshimasa Kuroda ◽

Hideyuki Takatsu

Keyword(s):

Heat Flux ◽

High Heat ◽

High Heat Flux ◽

Post Mortem ◽

First Wall ◽

Wall Panel

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Fabrication and high heat flux testing of plasma sprayed beryllium ITER first wall mock-ups

Journal of Nuclear Materials ◽

10.1016/s0022-3115(98)00078-6 ◽

1998 ◽

Vol 258-263 ◽

pp. 252-257 ◽

Cited By ~ 9

Author(s):

R.G Castro ◽

K.E Elliot ◽

R.D Watson ◽

D.L Youchison ◽

K.T Slattery

Keyword(s):

Heat Flux ◽

High Heat ◽

High Heat Flux ◽

First Wall ◽

Plasma Sprayed

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Evaluation of Strength on Dissimilar Metal Joints for ITER First Wall Components

ASME 2010 Pressure Vessels and Piping Conference: Volume 1 ◽

10.1115/pvp2010-26008 ◽

2010 ◽

Author(s):

H. Nishi ◽

M. Enoeda ◽

T. Hirose ◽

D. Tsuru ◽

H. Tanigawa

Keyword(s):

Heat Flux ◽

Stainless Steel ◽

Stress Singularity ◽

Dissimilar Materials ◽

High Heat ◽

High Heat Flux ◽

First Wall ◽

Cu Alloy ◽

Quarter Plane ◽

Plane Joint

The first wall (FW) of ITER blanket includes beryllium (Be) armor tiles joined to CuCrZr heat sink with stainless steel cooling tube and backing plate in order to improve plasma performance and reduce thermal stress. Therefore dissimilar materials joints are indispensable for fabricating the high heat flux components. Since these joints must withstand thermal and mechanical loads caused by the plasma and electromagnetic force, it is important to evaluate the strength and thermal fatigue life of dissimilar materials joints. When the dissimilar materials joints are subjected by external force and thermal loading, the stress of the joint may indicate singularity at the interface edge. Since the stress singularity may lower the strength of joints, the singularity is evaluated numerically for the various materials combinations and joint configuration to be used in high heat flux components of fusion reactors in this investigation. Moreover, tensile test and elasto-plastic FEM analysis are performed to investigate the fracture behavior of Be/Cu alloy and stainless steel/ Cu alloy obtained the FW mock-up. The results reveal two singular solutions of type rpj−1 for a half-plane bonded to a quarter-plane joint and the singularity is larger than that of a bonded quarter-planes joint. From the viewpoint of stress singularity, the configuration of bonded quarter-planes joint is better than the half-plane bonded to a quarter-plane joint. The singularity for W/Cu alloy combination is large compared to other combination of materials. Especially the singularity of stainless steel/ Cu alloy is very small. Tensile specimen of Be/CuCrZr joint fractured at the bonding interface due to the stress singularity. For the stainless steel/ Cu alloy, however, the specimens fractured at the Cu alloy region apart from the interface.

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High heat flux testing of first wall mock-ups with and without neutron irradiation

Nuclear Materials and Energy ◽

10.1016/j.nme.2016.02.003 ◽

2016 ◽

Vol 9 ◽

pp. 41-45 ◽

Cited By ~ 5

Author(s):

G. Pintsuk ◽

B. Bellin ◽

A. Gervash ◽

J. Linke ◽

N. Litunovsky ◽

...

Keyword(s):

Heat Flux ◽

Neutron Irradiation ◽

High Heat ◽

High Heat Flux ◽

First Wall

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Overview of the R&D Activities of Water Cooled Ceramic Breeder Blanket

18th International Conference on Nuclear Engineering: Volume 6 ◽

10.1115/icone18-30143 ◽

2010 ◽

Author(s):

Mikio Enoeda ◽

Takanori Hirose ◽

Hisashi Tanigawa ◽

Daigo Tsuru ◽

Akira Yoshikawa ◽

...

Keyword(s):

Heat Flux ◽

Martensitic Steel ◽

Side Wall ◽

High Heat ◽

Hydraulic Performance ◽

High Heat Flux ◽

Fabrication Technology ◽

First Wall ◽

Key Technologies ◽

Real Scale

This paper overviews the R&D activity of Water Cooled Ceramic Breeder (WCCB) Blanket in Japan. Japan is performing R&D of WCCB Blanket as the primary candidate of the breeding blanket for the fusion DEMO reactor. Regarding the development of blanket module fabrication technology, a real scale First Wall (FW) was fabricated using Reduced Activation Ferritic Martensitic Steel (RAFMS) F82H. Using fabricated FW mockup, thermo-hydraulic performance and high heat flux tests were successfully performed with the heat flux equivalent to ITER TBM condition, 0.5 MW/m2, 80 cycles with the coolant condition as DEMO, 15 MPa 300 °C. Also, real scale Side Wall (SW) and real scale breeder pebble bed structure have been successfully fabricated. Furthermore, assembling of the real scale FW plate mockup and SW plate mockup was successfully performed. Development of major key technologies for the WCCB TBM structure fabrication has been progress toward the establishment of fabrication technology of WCCB TBM.

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