Seismic response of reactor vessel internals for Korean standard nuclear power plant

1996 ◽  
Vol 165 (1-2) ◽  
pp. 57-66 ◽  
Author(s):  
Myung J. Jhung ◽  
Won G. Hwang
2012 ◽  
Vol 166-169 ◽  
pp. 2275-2282 ◽  
Author(s):  
Wen Guang Liu ◽  
Rui Dong Wang ◽  
Lei Hua ◽  
Wen Fu He

In this paper, the behavior of the structure of a pressurized water reactor (PWR) nuclear power plant (NPP) in China, is taken into consideration during a great earthquake especially beyond the design benchmark. The effects of earthquake energy absorption are analyzed using simplified multi-lumped mass system. The effects of site conditions, post yield stiffness, yield force on isolated reactor structure (IRS) are also discussed. The results show that isolation technology can significantly reduce seismic response of the reactor structure and achieve preferable earthquake energy absorption of the IRS beyond the design benchmark during a great earthquake. Earthquake wave characteristics and isolation layer parameters have direct effects on seismic response and the results of parameter analysis can provide reference for a correct and logical design of IRS.


Author(s):  
Jim Xu ◽  
Sujit Samaddar

The soil-structure interaction (SSI) has a significant impact on nuclear power plant (NPP) structures, especially for massive and rigid structures founded on soils, such as containments. The U.S. Nuclear Regulatory Commission’s (NRC) Standard Review Plan (SRP) provides the requirement and acceptance criteria for incorporating the SSI effect in the seismic design and analyses of NPP structures. The NRC staff uses the SRP for safety review of license applications. Recent studies have indicated that ground motions in recorded real earthquake events have exhibited spatial incoherency in high-frequency contents. Several techniques have been developed to incorporate the incoherency effect in the seismic response analyses. Section 3.7.2 of Revision 3 of the SRP also provided guidance for use in the safety evaluation of seismic analyses considering ground motion spatial incoherency effect. This paper describes a case study of the SSI and incoherency effects on seismic response analyses of NPP structures. The study selected a typical containment structure. The SSI model is generated based on the typical industry practice for SSI computation of containment structures. Specifically, a commercial version of SASSI was used for the study, which considered a surface-founded structure. The SSI model includes the foundation, represented with brick elements, and the superstructure, represented using lumped mass and beams. The study considered various soil conditions and ground motion coherency functions to investigate the effect of the range of soil stiffness and the ground motion incoherency effect on SSI in determining the seismic response of the structures. This paper describes the SSI model development and presents the analysis results as well as insights into the manner in which the SSI and incoherency effects are related to different soil conditions.


Author(s):  
Tae-Soon Kim ◽  
Jae-Gon Lee ◽  
Je-Jun Lee ◽  
Myeong-Man Park

The construction duration of a nuclear power plant has been considered as a important factor to occupy the competitive edge. For the optimization process of APR1400 which is nuclear reactor newly developed in Korea, it has been suggested that the modularization of reactor vessel internals (RVI) was one of useful means to reduce the construction duration. In general, RVI consists of three components such as core support barrel (CSB), lower support structure/core shroud (LSS/CS) and upper guide structure (UGS). It is complicated and tedious to assemble the RVI by the conventional method which requires about 8∼10 months. In order to modularize the RVI, the gap between the CSB snubber lug and the reactor vessel (RV) stabilization lug must be measured by a remote measurement method. By using a remote measurement method, the welding of CSB and LSS/CS can be performed in advance of the reactor installation process to reduce the construction duration of a nuclear power plant. Compared with the conventional method, the duration of about 2 months required in the welding of CSB and LSS/CS is finally reduced. In this study, first of all we developed the remote measuring system that included the digital probes to measure the 72 points of gap at once. The system device consists of digital probe section, pneumatic supply and control section, electric power section, remote control computer and program. The selected digital probe of linear variable differential transformer (LVDT) type and the calibration device for the zero-point adjustment jig and the other devices have sufficient reliability and accuracy. And the digital probe connection jig has sufficient consistency. The network and system for remote measurement were very stable and no disturbance at electromagnetic interference environment. And we carried out the proof test of our remote measuring system to evaluate the application on the real plant conditions using the RV and RVI mock-up. The results of remote measurement were compared with existing manual measuring method and the reliability of the system was verified. Finally, we confirmed that our remote measuring system had the efficient reliability could be applied to measure the gap of RVI.


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