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Proceedings Papers

Development of Leak Before Break Assessment Guidelines for Sodium Cooled Fast Reactors in Japan

Hiroki Yada, Takashi Wakai, Takayuki Miyagawa, Hideo Machida
Proc. ASME. PVP2021, Volume 1: Codes and Standards, V001T01A060, July 13–15, 2021
Paper No: PVP2021-61942
DOI: https://doi.org/10.1115/PVP2021-61942
View Paper titled, Development of Leak Before Break Assessment Guidelines for Sodium Cooled Fast Reactors in Japan
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Topics: Fast neutron reactors, Fracture (Materials), In-service inspection, Leakage, Leak-before-break, Sodium, Sodium fast reactors
Proceedings Papers

Example Proposals of Fracture Controlled Vessels and Piping for Failure Mitigations

Naoto Kasahara, Takashi Wakai, Izumi Nakamura, Takuya Sato, Masakazu Ichimiya
Proc. ASME. PVP2021, Volume 2: Computer Technology and Bolted Joints; Design and Analysis, V002T03A031, July 13–15, 2021
Paper No: PVP2021-61952
DOI: https://doi.org/10.1115/PVP2021-61952
View Paper titled, Example Proposals of Fracture Controlled Vessels and Piping for Failure Mitigations
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Topics: Design, Failure, Fracture (Materials), Fracture (Process), Pipes, Vessels
Proceedings Papers

Proposal of Simulation Material Test Technique for Clarifying the Structure Failure Mechanisms Under Excessive Seismic Loads

Ryuta Hashidate, Shoichi Kato, Takashi Onizawa, Takashi Wakai, Naoto Kasahara
Proc. ASME. PVP2021, Volume 2: Computer Technology and Bolted Joints; Design and Analysis, V002T03A029, July 13–15, 2021
Paper No: PVP2021-61866
DOI: https://doi.org/10.1115/PVP2021-61866
View Paper titled, Proposal of Simulation Material Test Technique for Clarifying the Structure Failure Mechanisms Under Excessive Seismic Loads
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Topics: Constitutive equations, Failure mechanisms, Lead alloys, Simulation, Stress
Proceedings Papers

Proposal of Simulation Materials Test Technique and Their Constitutive Equations for Structural Tests and Analyses Simulating Severe Accident Conditions

Ryuta Hashidate, Shoichi Kato, Takashi Onizawa, Takashi Wakai, Naoto Kasahara
Proc. ASME. PVP2020, Volume 3: Design and Analysis, V003T03A041, August 3, 2020
Paper No: PVP2020-21397
DOI: https://doi.org/10.1115/PVP2020-21397
View Paper titled, Proposal of Simulation Materials Test Technique and Their Constitutive Equations for Structural Tests and Analyses Simulating Severe Accident Conditions
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Topics: Accidents, Constitutive equations, Lead alloys, Simulation
Proceedings Papers

Application of Fracture Control to Mitigate Failure Consequence Under BDBE

Naoto Kasahara, Takashi Wakai, Izumi Nakamura, Takuya Sato, Masakazu Ichimiya
Proc. ASME. PVP2020, Volume 3: Design and Analysis, V003T03A038, August 3, 2020
Paper No: PVP2020-21072
DOI: https://doi.org/10.1115/PVP2020-21072
View Paper titled, Application of Fracture Control to Mitigate Failure Consequence Under BDBE
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Topics: Design, Failure, Failure mechanisms, Fracture (Materials), Fracture (Process)
Proceedings Papers

Research Plan and Progress to Realize Fracture Control of Nuclear Components

Naoto Kasahara, Takashi Wakai, Izumi Nakamura, Takuya Sato
Proc. ASME. PVP2019, Volume 3: Design and Analysis, V003T03A039, July 14–19, 2019
Paper No: PVP2019-93545
DOI: https://doi.org/10.1115/PVP2019-93545
View Paper titled, Research Plan and Progress to Realize Fracture Control of Nuclear Components
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Topics: Design, Failure mechanisms, Fracture (Materials)
Proceedings Papers

A Proposal of Inelastic Constitutive Equations of Lead Alloys Used for Structural Tests Simulating Severe Accident Conditions

Ryuta Hashidate, Takashi Onizawa, Takashi Wakai, Naoto Kasahara
Proc. ASME. PVP2019, Volume 3: Design and Analysis, V003T03A040, July 14–19, 2019
Paper No: PVP2019-93820
DOI: https://doi.org/10.1115/PVP2019-93820
View Paper titled, A Proposal of Inelastic Constitutive Equations of Lead Alloys Used for Structural Tests Simulating Severe Accident Conditions
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Topics: Accidents, Constitutive equations, Lead alloys
Proceedings Papers

Development of a Crack Opening Displacement Assessment Procedure Considering Change of Compliance at a Crack Part in Thin Wall Pipes Made of Modified 9Cr-1Mo Steel

Takashi Wakai, Hideo Machida, Manabu Arakawa, Seiji Yanagihara, Ryosuke Suzuki, Masaaki Matsubara
Proc. ASME. ICONE26, Volume 2: Plant Systems, Structures, Components, and Materials; Risk Assessments and Management, V002T03A035, July 22–26, 2018
Paper No: ICONE26-82619
DOI: https://doi.org/10.1115/ICONE26-82619
View Paper titled, Development of a Crack Opening Displacement Assessment Procedure Considering Change of Compliance at a Crack Part in Thin Wall Pipes Made of Modified 9Cr-1Mo Steel
Click here to open pdf in another window PDF for Development of a Crack Opening Displacement Assessment Procedure Considering Change of Compliance at a Crack Part in Thin Wall Pipes Made of Modified 9Cr-1Mo Steel
Topics: Displacement, Fracture (Materials), Pipes, Steel, Thin wall structures, Leakage, Sodium fast reactors, Sodium, Work hardening, Coolants
Proceedings Papers

Proposal of Simplified J-Integral Evaluation Method for a Through Wall Crack in SFR Pipe Made of Mod.9Cr-1Mo Steel

Takashi Wakai, Hideo Machida, Manabu Arakawa, Koichi Kikuchi
Proc. ASME. ETAM2018, ASME 2018 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, V001T03A001, April 3–5, 2018
Paper No: ETAM2018-6708
DOI: https://doi.org/10.1115/ETAM2018-6708
View Paper titled, Proposal of Simplified J-Integral Evaluation Method for a Through Wall Crack in SFR Pipe Made of Mod.9Cr-1Mo Steel
Click here to open pdf in another window PDF for Proposal of Simplified J-Integral Evaluation Method for a Through Wall Crack in SFR Pipe Made of Mod.9Cr-1Mo Steel
Topics: Evaluation methods, Fracture (Materials), Pipes, Sodium fast reactors, Steel, Finite element analysis, Stress, Failure analysis, Coolants, Cylinders
Proceedings Papers

Structural Materials and Code Development for Japanese Sodium-Cooled Fast Reactors

Tai Asayama, Yugi Nagae, Takashi Wakai, Kazuyuki Tsukimori, Masaki Morishita
Proc. ASME. ETAM2014, ASME 2014 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries, 296-302, March 25–27, 2014
Paper No: ETAM2014-1037
DOI: https://doi.org/10.1115/ETAM2014-1037
View Paper titled, Structural Materials and Code Development for Japanese Sodium-Cooled Fast Reactors
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Topics: Sodium fast reactors, Design, Fast neutron reactors, Japan Society of Mechanical Engineers, Construction, Cycles, Fitness-for-service, Industrial research, Leak-before-break, Reliability
Proceedings Papers

The Formulation of Material Characteristics of Austenitic Stainless Steels at Extremely High Temperature

Kenta Shimomura, Takashi Onizawa, Shoichi Kato, Masanori Ando, Takashi Wakai
Proc. ASME. PVP2017, Volume 3B: Design and Analysis, V03BT03A006, July 16–20, 2017
Paper No: PVP2017-65666
DOI: https://doi.org/10.1115/PVP2017-65666
View Paper titled, The Formulation of Material Characteristics of Austenitic Stainless Steels at Extremely High Temperature
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Topics: High temperature, Stainless steel, Accidents, Nuclear power stations, Creep, Numerical analysis, Safety, Finite element analysis, Finite element methods, Fukushima nuclear disaster, Japan, 2011
Proceedings Papers

Thermal Fatigue Test on Dissimilar Welded Joint Between Gr.91 and 304SS

Takashi Wakai, Sumio Kobayashi, Shoichi Kato, Masanori Ando, Hideki Takasho
Proc. ASME. ICONE25, Volume 2: Plant Systems, Structures, Components and Materials, V002T03A008, July 2–6, 2017
Paper No: ICONE25-66099
DOI: https://doi.org/10.1115/ICONE25-66099
View Paper titled, Thermal Fatigue Test on Dissimilar Welded Joint Between Gr.91 and 304SS
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Topics: Fatigue testing, Welded joints, Steel, Fatigue damage, Creep, Evaluation methods, Fatigue, Fatigue cracks, Finite element analysis, Alloys
Proceedings Papers

Development of Seismic Isolation Systems for Sodium-Cooled Fast Reactors in Japan

Nobuchika Kawasaki, Tomoyoshi Watakabe, Takashi Wakai, Tomohiko Yamamoto, Tsuyoshi Fukasawa, Shigeki Okamura
Proc. ASME. PVP2016, Volume 8: Seismic Engineering, V008T08A037, July 17–21, 2016
Paper No: PVP2016-63437
DOI: https://doi.org/10.1115/PVP2016-63437
View Paper titled, Development of Seismic Isolation Systems for Sodium-Cooled Fast Reactors in Japan
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Topics: Sodium fast reactors, Springs, Dampers, Design, Disks, Bearings, Buckling, Damping, Diluents, Earthquake resistant design
Journal Articles

The Welded Joint Strength Reduction Factors of Modified 9Cr–1Mo Steel for the Advanced Loop-Type Sodium Cooled Fast Reactor

Takuya Yamashita, Takashi Wakai, Takashi Onizawa, Kenichiro Satoh, Kenji Yamamoto
Journal: Journal of Pressure Vessel Technology
Article Type: Research-Article
J. Pressure Vessel Technol. December 2016, 138(6): 061403.
Paper No: PVT-15-1260
DOI: https://doi.org/10.1115/1.4034017
Published Online: September 2, 2016
View Article titled, The Welded Joint Strength Reduction Factors of Modified 9Cr–1Mo Steel for the Advanced Loop-Type Sodium Cooled Fast Reactor
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Topics: Base metals, Creep, Rupture, Sodium fast reactors, Steel, Stress, Welded joints, Temperature, Design
Journal Articles

A Screening Method for Prevention of Ratcheting Strain Derived From Movement of Temperature Distribution

Satoshi Okajima, Takashi Wakai, Masanori Ando, Yasuhiro Inoue, Sota Watanabe
Journal: Journal of Pressure Vessel Technology
Article Type: Research-Article
J. Pressure Vessel Technol. October 2016, 138(5): 051204.
Paper No: PVT-15-1222
DOI: https://doi.org/10.1115/1.4032989
Published Online: April 29, 2016
View Article titled, A Screening Method for Prevention of Ratcheting Strain Derived From Movement of Temperature Distribution
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Topics: Membranes, Stress, Temperature, Temperature distribution, Design
Proceedings Papers

Development of Structural Codes for JSFR Based on the System Based Code Concept

Tai Asayama, Takashi Wakai, Masanori Ando, Satoshi Okajima, Yuji Nagae, Shigeru Takaya, Takashi Onizawa, Kazuyuki Tsukimori, Masaki Morishita
Proc. ASME. PVP2014, Volume 1: Codes and Standards, V001T01A064, July 20–24, 2014
Paper No: PVP2014-28853
DOI: https://doi.org/10.1115/PVP2014-28853
View Paper titled, Development of Structural Codes for JSFR Based on the System Based Code Concept
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Topics: Construction, Design, Fast neutron reactors, Fitness-for-service, Industrial research, Japan Society of Mechanical Engineers, Leak-before-break, Reliability, Sodium fast reactors, Welding
Proceedings Papers

Proposal of the Screening Method for Prevention of the Accumulation of the Ratcheting Strain Derived From the Movement of the Temperature Distribution

Satoshi Okajima, Takashi Wakai, Masanori Ando, Yasuhiro Inoue, Sota Watanabe
Proc. ASME. PVP2014, Volume 1: Codes and Standards, V001T01A065, July 20–24, 2014
Paper No: PVP2014-28875
DOI: https://doi.org/10.1115/PVP2014-28875
View Paper titled, Proposal of the Screening Method for Prevention of the Accumulation of the Ratcheting Strain Derived From the Movement of the Temperature Distribution
Click here to open pdf in another window PDF for Proposal of the Screening Method for Prevention of the Accumulation of the Ratcheting Strain Derived From the Movement of the Temperature Distribution
Topics: Temperature distribution, Stress, Deformation, Design, Evaluation methods, Cylinders, Finite element methods, Wall thickness, Yield strength, Bending (Stress)
Proceedings Papers

A Study for Proposal of Welded Joint Strength Reduction Factors of Modified 9Cr-1Mo Steel for Japan Sodium Cooled Fast Reactor (JSFR)

Takashi Wakai, Takashi Onizawa, Takehiko Kato, Shingo Date, Koichi Kikuchi, Kenichiro Satoh
Proc. ASME. PVP2013, Volume 3: Design and Analysis, V003T03A105, July 14–18, 2013
Paper No: PVP2013-97091
DOI: https://doi.org/10.1115/PVP2013-97091
View Paper titled, A Study for Proposal of Welded Joint Strength Reduction Factors of Modified 9Cr-1Mo Steel for Japan Sodium Cooled Fast Reactor (JSFR)
Click here to open pdf in another window PDF for A Study for Proposal of Welded Joint Strength Reduction Factors of Modified 9Cr-1Mo Steel for Japan Sodium Cooled Fast Reactor (JSFR)
Topics: Sodium fast reactors, Steel, Welded joints, Creep, Rupture, Stress, Base metals, Design, Temperature, Damage
Proceedings Papers

Effect of Rotational Stiffness Evolution at Crack Part on Critical Crack Size in SFR

Takashi Wakai, Hideo Machida, Shinji Yoshida
Proc. ASME. PVP2012, Volume 6: Materials and Fabrication, Parts A and B, 713-721, July 15–19, 2012
Paper No: PVP2012-78061
DOI: https://doi.org/10.1115/PVP2012-78061
View Paper titled, Effect of Rotational Stiffness Evolution at Crack Part on Critical Crack Size in SFR
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Topics: Fracture (Materials), Sodium fast reactors, Stiffness, Pipes, Displacement, Stress, Evaluation methods, Leak-before-break, Piping systems, Springs
Journal Articles

Development of Leak-Before-Break Assessment Method for Japan Sodium Cooled Fast Reactor Pipe—Part 1 Crack Opening Displacement Assessment of Thin Wall Pipes Made of Modified 9Cr-1Mo Steel

Takashi Wakai, Hideo Machida, Manabu Arakawa, Shinji Yoshida, Yasuhiro Enuma
Journal: Journal of Pressure Vessel Technology
Article Type: Research-Article
J. Pressure Vessel Technol. February 2013, 135(1): 011401.
Paper No: PVT-11-1116
DOI: https://doi.org/10.1115/1.4007642
Published Online: December 4, 2012
View Article titled, Development of Leak-Before-Break Assessment Method for Japan Sodium Cooled Fast Reactor Pipe—Part 1 Crack Opening Displacement Assessment of Thin Wall Pipes Made of Modified 9Cr-1Mo Steel
Click here to open pdf in another window PDF for Development of Leak-Before-Break Assessment Method for Japan Sodium Cooled Fast Reactor Pipe—Part 1 Crack Opening Displacement Assessment of Thin Wall Pipes Made of Modified 9Cr-1Mo Steel
Topics: Displacement, Finite element analysis, Fracture (Materials), Pipes, Sodium fast reactors, Steel, Tension, Thin wall structures, Stress, Leak-before-break