scholarly journals Nonlinear Seismic Correlation Analysis of the JNES/NUPEC Large-Scale Piping System Tests

2008 ◽  
Author(s):  
Jinsuo Nie ◽  
Giuliano DeGrassi ◽  
Charles H. Hofmayer ◽  
Syed A. Ali
Keyword(s):  
Correlation Analysis ◽  
Test Data ◽  
Nuclear Power ◽  
Large Scale ◽  
Failure Modes ◽  
Plastic Behavior ◽  
Piping System ◽  
Highly Nonlinear ◽  
Piping Systems ◽  
The U.S

The Japan Nuclear Energy Safety Organization/Nuclear Power Engineering Corporation (JNES/NUPEC) large-scale piping test program has provided valuable new test data on high level seismic elasto-plastic behavior and failure modes for typical nuclear power plant piping systems. The component and piping system tests demonstrated the strain ratcheting behavior that is expected to occur when a pressurized pipe is subjected to cyclic seismic loading. Under a collaboration agreement between the U.S. and Japan on seismic issues, the U.S. Nuclear Regulatory Commission (NRC)/ Brookhaven National Laboratory (BNL) performed a correlation analysis of the large-scale piping system tests using detailed state-of-the-art nonlinear finite element models. Techniques are introduced to develop material models that can closely match the test data. The shaking table motions are examined. The analytical results are assessed in terms of the overall system responses and the strain ratcheting behavior at an elbow. The paper concludes with the insights about the accuracy of the analytical methods for use in performance assessments of highly nonlinear piping systems under large seismic motions.

Research Plan and Progress to Realize Fracture Control of Nuclear Components

2019 ◽  
Author(s):  
Naoto Kasahara ◽  
Takashi Wakai ◽  
Izumi Nakamura ◽  
Takuya Sato
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Large Scale ◽  
Failure Modes ◽  
Failure Behavior ◽  
Piping System ◽  
Piping Systems ◽  
Research Plan ◽  
Fracture Control ◽  
Accident Consequence

Abstract For safety improvement after Fukushima daiichi nuclear power plant accident, mitigation of accident consequence for Beyond Design Basis Events (BDBE) has become important. Authors propose application of fracture control concept for mitigation of accident consequence of nuclear plants as follows. In the case of reactor vessels under high temperature and pressure conditions, small cracks from local failure will release internal pressure and can avoid a large scale ductile fracture of general portions. For piping under excessive earthquake, repeated elastic-plastic deformation and ratchet deformation dissipate vibration energy and reduce input energy from floor. They can prevent collapse of piping systems or break of pipe wall. Strength of pipe supports can be designed lower than pipe itself. Controlling the failure of supports would lead to plastic deformation without the break. The ratio of the frequency of seismic loading to the natural frequency of the piping system would also affect the failure behavior of piping systems. This paper describes research plan and progress to realize fracture control of nuclear components. The first step is clarification of actual failure modes and their mechanisms. Next step is development of relative strength evaluation method among failure modes. The third step is proposals of failure control methods. One of example is a vessel under high pressure and high temperature loadings. Another example is pipe under excessive earthquake.

Non-Linear Design Verification of Nuclear Power Piping According to ASME III NB/NC

2008 ◽  
Author(s):  
Lingfu Zeng ◽  
Lennart G. Jansson
Keyword(s):  
Nuclear Power ◽  
Design Evaluation ◽  
Piping System ◽  
Design Verification ◽  
Intensive Study ◽  
Non Linear ◽  
Piping Systems ◽  
Design Requirements

A nuclear piping system which is found to be disqualified, i.e. overstressed, in design evaluation in accordance with ASME III, can still be qualified if further non-linear design requirements can be satisfied in refined non-linear analyses in which material plasticity and other non-linear conditions are taken into account. This paper attempts first to categorize the design verification according to ASME III into the linear design and non-linear design verifications. Thereafter, the corresponding design requirements, in particular, those non-linear design requirements, are reviewed and examined in detail. The emphasis is placed on our view on several formulations and design requirements in ASME III when applied to nuclear power piping systems that are currently under intensive study in Sweden.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Sensitivity Analyses for a PWR SCC Case Using the Probabilistic Loss-of-Coolant-Accident (Pro-LOCA) Software

2016 ◽  
Author(s):  
Bruce A. Young ◽  
Sang-Min Lee ◽  
Paul M. Scott
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
The United States ◽  
Design Criterion ◽  
Mitigation Strategies ◽  
Sensitivity Analyses ◽  
Base Case ◽  
Piping System ◽  
Loss Of Coolant Accident ◽  
Piping Systems

As a means of demonstrating compliance with the United States Code of Federal Regulations 10CFR50 Appendix A, General Design Criterion 4 (GDC-4) requirement that primary piping systems for nuclear power plants exhibit an extremely low probability of rupture, probabilistic fracture mechanics (PFM) software has become increasingly popular. One of these PFM codes for nuclear piping is Pro-LOCA which has been under development over the last decade. Currently, Pro-LOCA is being enhanced under an international cooperative program entitled PARTRIDGE-II (Probabilistic Analysis as a Regulatory Tool for Risk-Informed Decision GuidancE - Phase II). This paper focuses on the use of a pre-defined set of base-case inputs along with prescribed variation in some of those inputs to determine a comparative set of sensitivity analyses results. The benchmarking case was a circumferential Primary Water Stress Corrosion Crack (PWSCC) in a typical PWR primary piping system. The effects of normal operating loads, temperature, leak detection, inspection frequency and quality, and mitigation strategies on the rupture probability were studied. The results of this study will be compared to the results of other PFM codes using the same base-case and variations in inputs. This study was conducted using Pro-LOCA version 4.1.9.

Effects on Pipe Vibrations of Cavitation in an Orifice and in Globe-Style Valves

2006 ◽  
Author(s):  
Se´bastien Caillaud ◽  
Rene´-Jean Gibert ◽  
Pierre Moussou ◽  
Joe¨l Cohen ◽  
Fabien Millet
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Low Frequency ◽  
Flow Regimes ◽  
Piping System ◽  
Low Frequencies ◽  
Choked Flow ◽  
Single Hole ◽  
Piping Systems ◽  
Large Amplitude Vibrations

A piping system of French nuclear power plants displays large amplitude vibrations in particular flow regimes. These troubles are attributed to cavitation generated by single-hole orifices in depressurized flow regimes. Real scale experiments on high pressure test rigs and on-site tests are then conducted to explain the observed phenomenon and to find a solution to reduce pipe vibrations. The first objective of the present paper is to analyze cavitation-induced vibrations in the single-hole orifice. It is then shown that the orifice operates in choked flow with supercavitation, which is characterized by a large unstable vapor pocket. One way to reduce pipe vibrations consists in suppressing the orifices and in modifying the control valves. Three technologies involving a standard trim and anti-cavitation trims are tested. The second objective of the paper is to analyze cavitation-induced vibrations in globe-style valves. Cavitating valves operate in choked flow as the orifice. Nevertheless, no vapor pocket appears inside the pipe and no unstable phenomenon is observed. The comparison with an anti-cavitation solution shows that cavitation reduction has no impact on low frequency excitation. The effect of cavitation reduction on pipe vibrations, which involve essentially low frequencies, is then limited and the first solution, which is the standard globe-style valve installed on-site, leads to acceptable pipe vibrations. Finally, this case study may have consequences on the design of piping systems. First, cavitation in orifices must be limited. Choked flow in orifices may lead to supercavitation, which is here a damaging and unstable phenomenon. The second conclusion is that the reduction of cavitation in globe-style valve in choked flow does not reduce pipe vibrations. The issue is then to limit cavitation erosion of valve trims.

Analysis of Pressure Pulsations in Reciprocating Compressor Piping Systems

1966 ◽  
Vol 88 (2) ◽  
pp. 164-168 ◽  
Author(s):  
S. S. Grover
Keyword(s):  
Field Test ◽  
Test Data ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Practical Application ◽  
Pressure Pulsations ◽  
System A ◽  
Piping Systems ◽  
Limiting Condition

This paper deals with pulsations in pressure and flow in the reciprocating compressor and connected piping system. A model is presented that describes the excitation at the compressor and the propagation of the pulsations in the interconnected piping. It has been adapted to digital computations to predict the pulse magnitudes in reciprocating compressor piping systems and to assess measures for their control. Predicted results have been compared with field test data and with simplified limiting condition results. A discussion of its practical application is included.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 2 — Application of CCFS Method to the Multiply Supported Systems

2014 ◽  
Author(s):  
Koichi Tai ◽  
Keisuke Sasajima ◽  
Shunsuke Fukushima ◽  
Noriyuki Takamura ◽  
Shigenobu Onishi
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Time History ◽  
Piping System ◽  
History Analysis ◽  
Piping Systems ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper provides a part of series of “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. Paper is focused on the seismic evaluation method of the multiply supported systems, as the one of the design methodology adopted in the equipment and piping system of the seismic isolated nuclear power plant in Japan. Many of the piping systems are multiply supported over different floor levels in the reactor building, and some of the piping systems are carried over to the adjacent building. Although Independent Support Motion (ISM) method has been widely applied in such a multiply supported seismic design of nuclear power plant, it is noted that the shortcoming of ignoring correlations between each excitations is frequently misleaded to the over-estimated design. Application of Cross-oscillator, Cross-Floor response Spectrum (CCFS) method, proposed by A. Asfura and A. D. Kiureghian[1] shall be considered to be the excellent solution to the problems as mentioned above. So, we have introduced the algorithm of CCFS method to the FEM program. The seismic responses of the benchmark model of multiply supported piping system are evaluated under various combination methods of ISM and CCFS, comparing to the exact solutions of Time History analysis method. As the result, it is demonstrated that the CCFS method shows excellent agreement to the responses of Time History analysis, and the CCFS method shall be one of the effective and practical design method of multiply supported systems.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: Computational Approach

2007 ◽  
Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Analytical Model ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Seismic Load ◽  
Piping System ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Seismic Loadings ◽  
Local Wall Thinning

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.

Seismic Proving Test of Ultimate Piping Strength: Test Results on Piping Component and Simplified Piping System

2002 ◽  
Author(s):  
Kenichi Suzuki ◽  
Y. Namita ◽  
H. Abe ◽  
I. Ichihashi ◽  
Kohei Suzuki ◽  
...  
Keyword(s):  
Large Scale ◽  
Safety Margin ◽  
Current Status ◽  
Piping System ◽  
Test Results ◽  
Seismic Safety ◽  
System A ◽  
Seismic Design Code ◽  
Piping Systems ◽  
Technical Issues

In 1998FY, the 6 year program of piping tests was initiated with the following objectives: i) to clarify the elasto-plastic response and ultimate strength of nuclear piping, ii) to ascertain the seismic safety margin of the current seismic design code for piping, and iii) to assess new allowable stress rules. In order to resolve extensive technical issues before proceeding on to the seismic proving test of a large-scale piping system, a series of preliminary tests of materials, piping components and simplified piping systems is intended. In this paper, the current status of the piping component tests and the simplified piping system tests is reported with focus on fatigue damage evaluation under large seismic loading.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2007 ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Difference

In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3-D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned wall elbow, because the life of piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

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