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Journal Articles

Effect of 3-D initial imperfections on the deformation behaviors of head plates subjected to convex side pressure

Yada, Hiroki; Ando, Masanori; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 9 Pages, 2018/07

Containment vessel (CV) of nuclear power plants is an important structure to prevent radioactive release, however, the safety margin of the CV against pressure are not numerically clarified. The head plate structure is included in CV boundary of fast reactor. In order to develop the evaluation method of the ultimate strength of the head plate structure at beyond the specified limit, pressure failure tests and finite element analysis (FEA) of the head plates subjected to convex side pressure were performed. In the test of the relative thin thickness head plate, non-axisymmetric deformations was observed in post buckling behavior and failure pressure was lower than other cases. To evaluate non-axisymmetric deformations in the test, FEA using 3-D solid model constructed by precise dimensions of the test specimen, moreover, FEA using simplified model with uniform or non-uniform thickness were performed. Through analyses, the feature of the post buckling behavior was discussed.

Journal Articles

Application of JSME Seismic Code Case by elastic-plastic response analysis to practical piping system

Otani, Akihito*; Kai, Satoru*; Kaneko, Naoaki*; Watakabe, Tomoyoshi; Ando, Masanori; Tsukimori, Kazuyuki*

Proceedings of 2018 ASME Pressure Vessels and Piping Conference (PVP 2018), 10 Pages, 2018/07

This paper demonstrates an application result of the JSME Seismic Code Case to an actual complex piping system. The secondary coolant piping system of Japanese Fast Breeder Reactor, Monju, was selected as a representative of the complex piping systems. The elastic-plastic time history analysis for the piping system was performed and the piping system has been evaluated according to the JSME Seismic Code Case. The evaluation by the Code Case provides a reasonable result in terms of the piping fatigue evaluation that governs seismic integrity of piping systems.

Journal Articles

Leak rate tests of penetrate cracked head plates and modeling of head plate thickness distribution for 3-D analyses

Tsukimori, Kazuyuki*; Yada, Hiroki; Ando, Masanori; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 12th International Conference on Asian Structure Integrity of Nuclear Components (ASINCO-12) (CD-ROM), p.105 - 121, 2018/04

In FBR plants the head plate constitutes a part of the boundary of the containment vessel (CV), therefore, it is an important issue if the function as the boundary is maintained or not in the severe accident. And also it is important to evaluate the leak rate from the penetrated crack of the head plate, in order to estimate the effect of released fission product out of CV. Authors conducted pressure endurance tests of head plate specimens subjected to external pressure, which covered post-buckling behaviors and until crack penetration. In this paper leak rate test results at several pressure levels are introduced and the tendency of leak rate behaviors with relation of the penetrate crack length and the pressure level are discussed. Also, the modeling of head plate thickness distribution for 3-D analyses based on the detailed 3-D measurement data of specimens is discussed, which possibly relates to the 3-D deformation patterns observed in the tests and the length of penetration cracks.

Journal Articles

Experimental study on the deformation and failure of the bellows structure beyond the designed internal pressure

Ando, Masanori; Yada, Hiroki; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Journal of Pressure Vessel Technology, 139(6), p.061201_1 - 061201_12, 2017/08

 Times Cited Count:1 Percentile:10.91(Engineering, Mechanical)

In this study, in order to develop the evaluation method of the ultimate pressure of the bellows structure subject to the internal pressure beyond the specified, the failure test and finite element analysis (FEA) of the bellows structure were performed. The failure modes were demonstrated through the series of tests, and three kind of failure mode were observed. To simulate the buckling and deformation behavior during the test, the implicit and explicit analyses were performed.

Journal Articles

Experimental study on behaviours of two-ply bellows subjected to pressure and displacement loads

Tsukimori, Kazuyuki; Ando, Masanori; Yada, Hiroki; Ichimiya, Masakazu*; Anoda, Yoshinari*; Arakawa, Manabu*

Transactions of 24th International Conference on Structural Mechanics in Reactor Technology (SMiRT-24) (USB Flash Drive), 10 Pages, 2017/08

The analytical treatment of Multi-ply bellows behaviours is difficult compared with that of single-ply bellows, since the uncertainty of friction between plies exists. In this study verification was conducted based on experiments by comparing between two-ply and single-ply bellows test results. Following results were obtained. The spring rate of two-ply bellows is approximately twice of that of single-ply bellows, even if internal pressure is loaded. Typical buckling behaviour of bellows, in-plane squirm, was observed in both cases of two-ply and single-ply bellows. The deformation patterns were similar with each other, but the pressure levels of two-ply bellows were approximately twice of those of single-ply bellows. These means the friction force can be ignored practically. As the conclusion, two-ply bellows analyses can be replaced by the analyses of single-ply bellows model with half pressure load and the effort of numerical analysis can be reduced.

Journal Articles

Experimental demonstration of failure modes on bellows structures subject to internal pressure

Ando, Masanori; Yada, Hiroki; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 11 Pages, 2017/07

In this study, in order to develop the evaluation method of the pressure toughness of bellows structure under the beyond design base event, the pressure failure tests and finite element analysis (FEA) of the bellows structure subjected to internal pressure were performed. In the test of five convolutions 0.5 mm-thickness bellows specimen with guard pipe, the maximum pressure was larger than those in the tests without guard pipe specimens and ductile failure was observed. On the other hand, in the test of five convolutions 0.5 mm-thickness bellows specimen without guard pipe, local failure was observed. In the test of the six convolutions 1.0 mm-thickness bellows specimen, ductile failure was observed in the both single and double ply bellows. The maximum pressure obtained in all tests were about 10 times larger than the estimated results of limiting design pressure based on in-plain instability by the EJMA standards.

Journal Articles

Failure mode of ED and AD type head plates subject to convex side pressure

Yada, Hiroki; Ando, Masanori; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 8 Pages, 2017/07

The head plate that composes the boundary between primary and secondary coolant in intermediate heat exchanger of FBR has an important role when the progress of the BDBE is considered. In order to develop the evaluation method of the pressure toughness of the head plate under the BDBE, the pressure failure tests and finite element analysis of two types of head plate subjected to convex side pressure was performed in this study. It can be concluded that a failure mode of a head plate subjected convex side pressure is circumferential through-wall crack caused by straightening following the bending deformation near the rim.

Journal Articles

Experimental study on ultimate strength of single and double type bellows under internal pressure

Ando, Masanori; Yada, Hiroki; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 8 Pages, 2016/07

To clarify the progress of the events under the beyond design basis events, it is necessary to evaluate the pressure toughness of containment vessel adequately. The containment vessel of fast reactor is composed of the various structures, and one of the thinnest boundary structures is bellows structure to absorb the thermal expansion of the coolant piping penetrating the containment vessel. In addition to the containment vessel boundary, evaluating the pressure toughness of reactor coolant and gas boundary is also important because of same reason of that in the containment vessel boundary. In the primary coolant and gas boundary, the cover gas bellows of the intermediate heat exchanger in fast reactor is one of the thinnest structures and has important role when the progress of the BDBE is considered. Therefore, in order to develop the evaluation method of the pressure toughness of bellows structure under the BDBE, the pressure failure tests and finite element analysis of the bellows structure subjected to internal pressure were performed in this study.

Journal Articles

Experimental study on ultimate strength of a ellipsoidal dished head plate under pressure on convex surface

Yada, Hiroki; Ando, Masanori; Tsukimori, Kazuyuki; Ichimiya, Masakazu*; Anoda, Yoshinari*

Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 7 Pages, 2016/07

no abstracts in English

Journal Articles

Investigation on ultimate strength of thin wall tee pipe for sodium cooled fast reactor under seismic loading

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Otani, Akihito*; Moriizumi, Makoto; Kaneko, Naoaki*

Mechanical Engineering Journal (Internet), 3(3), p.16-00054_1 - 16-00054_11, 2016/06

It is important to investigate the failure mode and ultimate strength of piping components in order to evaluate the seismic integrity of piping. Many failure tests of thick wall and high pressure piping for Light Water Reactors (LWRs) have been conducted, and the results suggest that the failure mode that should be considered in the design of a thick wall piping for LWRs under seismic loading is low cycle fatigue. On the other hand, Sodium cooled Fast Reactors (SFRs) is thin wall when compared to LWRs piping. Failure tests of a thin wall piping are necessary because past failure tests for LWRs piping are not enough to discuss failure behavior of a thin wall piping. Therefore, this present work investigated the failure mode and the ultimate strength of thin wall tees.

Journal Articles

Ultimate strength of a thin wall elbow for sodium cooled fast reactors under seismic loads

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Kitamura, Seiji; Morishita, Masaki

Journal of Pressure Vessel Technology, 138(2), p.021801_1 - 021801_10, 2016/04

 Times Cited Count:4 Percentile:30.99(Engineering, Mechanical)

With a purpose of identifying the failure mode and the associating ultimate strength of piping components against seismic integrity, many kinds of failure tests have been conducted for thick wall piping for Light Water Reactors (LWRs). However, there are little failure test data on thin wall piping for Sodium Cooled Fast Reactors (SFRs). In this paper, a series of failure tests on thin wall elbows for SFRs is presented. Based on the tests, the failure mode of a thin wall piping component under seismic loads was identified to be fatigue. The safety margin included in the current design methodology was clarified quantitatively.

Journal Articles

Study on behaviours of multi-ply bellows subjected to pressure and displacement loads

Tsukimori, Kazuyuki; Ando, Masanori; Yada, Hiroki

Transactions of 23rd International Conference on Structural Mechanics in Reactor Technology (SMiRT-23) (USB Flash Drive), 10 Pages, 2015/08

Multi-ply bellows is widely used because its flexibility and pressure tightness. However, the analytical treatment of its behaviours is difficult compared with that of single-ply bellows, since the uncertainty of friction between plies exists. In this paper the strength evaluation equations of multi-ply bellows are examined and the friction effect between plies is investigated through simplified models and detailed FEM analyses of two-ply bellows for example including the effect of material plasticity and internal pressure. Mainly following results are obtained. (1) The behaviours of two-ply bellows without friction can be analysed approximately by using single-ply bellows model even in the elastic-plastic region. The effort of numerical analysis can be reduced if two-ply bellows analyses can be replaced by the analyses of single-ply bellows model. (2) The effect of friction is relatively small up to about 0.4 by friction coefficient. Therefore, the behaviours of two-ply bellows can be evaluated practically ignoring friction effect. (3) The strength of multi-ply bellows against pressure, i.e. buckling, can be evaluated conservatively by assuming no friction, even if considered the internal pressure with friction. Therefore, the evaluation method without friction is recommended for design.

Journal Articles

Investigation on ultimate strength of thin wall tee pipe for sodium cooled fast reactor under seismic loading

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Otani, Akihito*; Moriizumi, Makoto; Kaneko, Naoaki*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05

Journal Articles

Validation of nonlinear FEA models of a thin-walled elbow under extreme loading conditions for sodium-cooled fast reactors

Watakabe, Tomoyoshi; Jin, C.*; Usui, Yoshiya*; Sakai, Shinkichi*; Wakai, Takashi; Oshika, Junji*; Tsukimori, Kazuyuki

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05

Journal Articles

Study on strength of thin-walled tee pipe for fast breeder reactors under seismic loading

Watakabe, Tomoyoshi; Tsukimori, Kazuyuki; Otani, Akihito*; Moriizumi, Makoto; Kaneko, Naoaki*

Proceedings of 2014 ASME Pressure Vessels and Piping Conference (PVP 2014) (DVD-ROM), 8 Pages, 2014/07

In recent years, earthquakes over design condition were observed in Japan. Confirming the ultimate strength and design safety margin of mechanical components is important for the seismic integrity. This study focused on piping components, and it was one of the most important mechanical components for protecting boundary of coolant. Failure tests of thick-walled piping components for Light Water Reactors (LWRs) described previously in the literature. According to these tests, the failure mode of thick-walled piping components under seismic cyclic loading was low cycle fatigue. However, failure tests have scarcely been performed on thin-walled piping components pressurized at low levels for Fast Breeder Reactors (FBRs). This paper presents dynamic failure tests of thin-walled piping components in FBRs. Based on the test results, the failure mode, the ultimate strength, and the elastic-plastic behavior are discussed.

Journal Articles

Study on piping response under multiple excitation (validation for elastic-plastic analysis of piping)

Kai, Satoru*; Watakabe, Tomoyoshi; Kaneko, Naoaki*; Tochiki, Kunihiro*; Moriizumi, Makoto; Tsukimori, Kazuyuki

Proceedings of 2014 ASME Pressure Vessels and Piping Conference (PVP 2014) (DVD-ROM), 10 Pages, 2014/07

Piping in a nuclear power plant is usually laid across several floors of a single building or adjacent buildings, and is supported at many points. As the piping is excited by a large earthquake through multiple supporting points, seismic response analysis by multiple excitations within the range of plastic deformation of piping material is necessary to obtain the precise seismic response of the piping. This paper reports the validation results of the seismic elastic-plastic time history analysis of piping compared with the results of the shaking test of a 3-dimensional piping model under a plastic deformation range using triple uni-axial shake table.

Journal Articles

Development of structural codes for JSFR based on the system based code concept

Asayama, Tai; Wakai, Takashi; Ando, Masanori; Okajima, Satoshi; Nagae, Yuji; Takaya, Shigeru; Onizawa, Takashi; Tsukimori, Kazuyuki; Morishita, Masaki

Proceedings of 2014 ASME Pressure Vessels and Piping Conference (PVP 2014) (DVD-ROM), 6 Pages, 2014/07

This paper overviews the ongoing research and development as well as activities for codification of structural codes for the Japan Sodium Cooled Fast Reactor (JSFR). Not only the design and construction code which has been published and updated on a regular basis, codes on welding, fitness-for-service, leak-before-break evaluation as well as the guidelines for structural reliability evaluation are being developed. The basic strategy for the development is to fully take advantage of the favorable technical characteristics associated with sodium-cooled fast reactors; the codes will be developed based on the System Based Code concept. The above mentioned set of codes are planned to be published from the Japan Society of Mechanical Engineers in 2016.

Journal Articles

Development of constitutive models for fast reactor design

Tsukimori, Kazuyuki; Iwata, Koji*; Kawasaki, Nobuchika*; Okajima, Satoshi; Yada, Hiroki; Kasahara, Naoto*

Nuclear Engineering and Design, 269, p.23 - 32, 2014/04

 Times Cited Count:1 Percentile:10.7(Nuclear Science & Technology)

R&D to enable a practical fast breeder reactor plant is proceeding in Japan, which is called "FaCT" (Fast reactor Cycle Technology development). One of the key issues of R&D is to realize a reasonably compact reactor vessel by eliminating the wall protection equipment which is installed inside the vessel in order to reduce thermal loading in the conventional design. Most important concern is the amount of the inelastic strain of the vessel accumulated around the liquid sodium surface which moves upward and downward cyclically with start-up and shut-down. The aim of this study is to develop rational constitutive models that enable prediction of this kind of complex inelastic behaviors precisely and to prepare the design guide based on inelastic analysis. We developed a high accuracy plasticity model and a simplified plasticity model and valuated them by organized experiments.

Journal Articles

Demonstration of Leak-Before-Break in Japan sodium cooled fast reactor (JSFR) pipes

Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Xu, Y.*; Tsukimori, Kazuyuki

Nuclear Engineering and Design, 269, p.88 - 96, 2014/04

 Times Cited Count:12 Percentile:75.09(Nuclear Science & Technology)

Journal Articles

Study on piping response under multiple excitations; Triple shaking table test of piping having three-supporting anchors

Watakabe, Tomoyoshi; Kaneko, Naoaki*; Aida, Shigekazu*; Otani, Akihito*; Tsukimori, Kazuyuki; Moriizumi, Makoto; Kitamura, Seiji

Dynamics and Design Conference 2013 (D&D 2013) Koen Rombunshu (USB Flash Drive), 8 Pages, 2013/08

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many anchors. As the piping is excited by multiple inputs from the supporting anchors during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few tests involving such multiple excitations have been performed to verify the validity of multiple excitation analysis. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and verify the validity of the analysis method by multiple excitation test. This paper reports on the result of the shaking test using triple uni-axial shaking tables and a 3-dimensional piping model.

185 (Records 1-20 displayed on this page)