scholarly journals Study on Reliability Improvement of Main Steam Isolation Valve Control in Nuclear Power Plants

2021 ◽  
Vol 2005 (1) ◽  
pp. 012215
Author(s):  
Changxian Gan ◽  
Tian Wan ◽  
Weiwei Pan ◽  
Shengzhi Liu ◽  
Lei Tang ◽  
...  
Author(s):  
Hideaki Itabashi ◽  
Yoshitaka Tsutsumi ◽  
Koji Nishino ◽  
Shin Kumagai

Abstract The functional requirements of Main Steam Isolation Valves (MSIVs) provided in the Boiling Water Reactor (BWR) nuclear power plants in Japan have been previously evaluated via seismic tests and so forth. However, since the response acceleration has increased in line with a recent reassessment of standard earthquake ground motions, it is necessary to evaluate seismic operability with respect to high acceleration. In addition, from the viewpoint of equipment fragility in seismic PRA, it is necessary to determine practical seismic operability limits. We used a resonant shaking table in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels previously unachievable, and in seismic tests carried out on an MSIV, we obtained results confirming that validated seismic operability was possible even at response accelerations as high as 15 × 9.8 m/s2. The seismic operability results obtained for this MSIV will be applied to a fragility analysis of seismic PRA.


Author(s):  
Dalei Pan ◽  
Shenjie Gu ◽  
Guangyue Guo ◽  
Hongbo Kuang ◽  
Hua Zhong ◽  
...  

The driving device of the main steam and feed water isolation valves is one of the most important electromechanical equipment in nuclear power plants, and its motion performances are related to the safety of nuclear power plants. This article proposes an optimization methodology to research the motion performances. In the methodology, inputs are the motion performance indexes and the major influencing parameters with no need for complex mathematical models of the electromechanical equipment; the co-simulation model or the prototype are adopted to illustrate the influence rules of major parameters on the motion performance indexes; objective functions for optimization, which combine motion performances with weight factors, can reveal the influence rule curves. Then based on the methodology, motion performances of the equipment are analyzed and the key indexes are selected. Besides, the maximum pressure of the driving device is chosen as the major parameter and a dimensionless objective function synthesizing the motion performance indexes is proposed. Finally, the influence rule curve where the dimensionless function varies with the maximum pressure is obtained by the co-simulation and the experimental study on the prototype verifies the results, which provides references for the further research and development in the engineering application. For other electromechanical equipment, the method is an efficient tool to design, verify, and optimize the performances.


Author(s):  
Xian Zeng ◽  
Hong Xia ◽  
YeMin Dong ◽  
Zhen Liu

This paper focuses on the analysis of fatigue life for main steam isolation valve (MSIV) in nuclear power plants (NPPs). The contraction of throat is also in the form of sonic resonance cavity, which causes big vibration and noise. The vibration result in the fretting fatigue, which is the reason of the contact surface damage of the disc and the disc guide. By using FEM, the distribution of the stress on the contact surfaces of the disc and the disc guide was calculated. The influences of vibration on the distribution of the stress on the contact surfaces, together with the effect of the contact stress on the initiation of fretting fatigue cracks and fretting fatigue life have been studied. A critical plane approach the Smith–Watson–Topper fatigue parameter has also been adopted here, to predict crack initiation position and orientation, fatigue life. The results show that the predicted cracks location and fatigue life are well accordance with the practical situation.


Author(s):  
Keisuke Kitsukawa ◽  
Hiroshi Yokota ◽  
Koichi Murayama ◽  
Hiroshi Ueda ◽  
Yasukazu Takada ◽  
...  

As one of the Codes for Nuclear Power Generation Facilities, “Rules on Protection Design against Postulated Pipe Rupture for Nuclear Power Plants (JSME S ND1-2002)” has been developed by the JSME Committee on Power Generation Facility Codes from October 2001 and published in December 2002. The code covers the design for protection against postulated pipe rupture in nuclear power plants and gives the basic plan of protection design, locations of postulated pipe rupture, methods of determining the rupture type and opening area, and a procedure for evaluating jet impingement phenomena. It is a special feature of the code that the LBB (Leak Before Break) concept is applied to the determination of the piping rupture type, which belongs to RCPB, or to the main steam and feed water system inside the PWR containment vessel. Types of piping material applicable to the LBB concept are austenitic stainless steel, carbon steel and low-alloy steel. Furthermore, the code provides the flow and the method of LBB evaluation. In this paper, we describe the major rules of the code, including an outline of LBB evaluation methods.


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