Development of Design Methods for Piping Systems in a Seismically Base Isolated Nuclear Plant

2016 ◽  
Author(s):  
Timothy M. Adams ◽  
Eun Woo Ahn ◽  
Sungjune Kim ◽  
Sookyum Kim ◽  
Deasoo Kim
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Event ◽  
Base Isolation ◽  
Design Methods ◽  
Large Displacements ◽  
Plant Design ◽  
Isolation System ◽  
Piping Systems ◽  
Base Isolation System

KEPCO Engineering and Construction is developing a Nuclear Power Plant Design that places the Nuclear Island on a base isolation system while the remaining plant structures are on standard structural foundations. When subjected to seismic (earthquake) loading, this will result in large differential displacements between the nuclear island and the adjacent buildings. Critical piping systems, which must remain functional during and after the seismic event, must withstand the large displacements. This paper summarizes the studies conducted to develop design methods for such piping systems. Also presented are the recommended approaches to be used in the design of such piping systems.

scholarly journals Isolation of nuclear power plants from earthquake attack

1976 ◽  
Vol 9 (4) ◽  
pp. 199-204
Author(s):  
R. I. Skinner ◽  
R. G. Tyler ◽  
S. B. Hodder
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Base Isolation ◽  
Isolation System ◽  
Base Isolation System ◽  
Critical Components ◽  
Fuel Elements ◽  
Control Rods ◽  
Very High

The analysis of one-mass and two-mass models indicates that the earthquake-generated horizontal forces and deformations of the main structures of a nuclear power plant can be reduced by a factor of about ten times by mounting the overall power plant building on a recently developed base-isolation system. The very high forces which the ‘resonant appendage‘ effect may induce in some critical components (such
 as fuel elements, control rods and essential piping) may be reduced by a factor of 40 or more times by the isolation system. The parameters of
 the isolation system have been chosen as appropriate to the level of protection which should be provided for a nuclear plant in a seismically active area. Consideration is given to flexible mounts and dampers suitable for such an isolator.

Study on Three-Dimensional Seismic Isolation System for Next Generation Nuclear Power Plant: Independent Cable Reinforced Rolling-Seal Air Spring

2004 ◽  
Author(s):  
Mitsuru Kageyama ◽  
Yoshihiko Hino ◽  
Satoshi Moro
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Outer Diameter ◽  
Next Generation ◽  
Air Spring ◽  
Isolation System ◽  
Rubber Sheet

In Japan, the development of the next generation NPP has been conducted in recent years. In the equipment/piping design of the plant, seismic condition has been required much more mitigate than before. So, the three-dimensional (abbreviation to 3D) seismic isolation system development has also been conducted since 2000. The superlative 3D base isolation system for the entire building was proposed. The system is composed of cable reinforced air springs, rocking arresters and viscous dampers. Dimensions of the air spring applied to the actual power plant are 8 meters in the outer-diameter and 3.5 meters in height. The allowable half strokes are 1.0 meters in horizontal and 0.5 meters in vertical respectively. The maximum supporting weight for a single device is 70 MN. The inner design air pressure is about 1.8MPa. This air spring has a distinguishing feature, which realizes 3D base isolation with a single device, whose natural periods are about 4 seconds in horizontal and about 3 seconds in vertical. In order to verify the 3D performance of this system, several feasibility tests were conducted. Firstly, 3D shaking table tests were conducted. The test specimen is scaled 1/4 of the actual device. The outer diameter and inner air pressure of air spring is 2 meters and 0.164 MPa. Next, a pressure resistant test for the sub cable, textile sheet and rubber sheet, which composed air spring, were conducted as a full scale model test. Then, air permeation test for the rubber sheet was also conducted. As a result, the proposed system was verified that it could be applied to the actual nuclear power plants.

Three Dimensional Seismic Isolation System for Next-Generation Nuclear Power Plant With Rolling Seal Type Air Spring and Hydraulic Rocking Suppression System

2005 ◽  
Author(s):  
Takahiro Shimada ◽  
Junji Suhara ◽  
Kazuhiko Inoue
Keyword(s):  
Dynamic Loading ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Loading Test ◽  
Isolation System ◽  
Ability Test ◽  
Base Isolation System ◽  
Suppression System

Three dimensional (3D) seismic isolation devices have been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed seismic isolation system is composed of rolling seal type air springs and the hydraulic type springs with rocking suppression system for vertical base isolation device. In horizontal direction, the same laminated rubber bearings are used as horizontal isolation device for these systems. The performances and the applicability have already been evaluated by the technical feasibility tests and performance tests for each system. In this study, it was evaluated that the performance of the 3D base isolation system with rolling seal type air springs combined with hydraulic rocking suppression devices. A 1/7 scaled model of the 3D base isolation devices were manufactured and some performance test were executed for each device. For the rolling seal type air springs, dynamic loading test was executed with a vibration table, and pressure resistant ability test was executed for reinforced air springs. In the dynamic loading test, it is confirmed that the natural period and damping performance were verified. In the pressure resistant ability test, it is confirmed that the air springs had sufficient strength. For the hydraulic rocking suppression system, forced dynamic loading test was carried out in order to measure the frictional and oil flow resistance force on each cylinder. And the vibration table tests were carried out with supported weight of 228 MN in order to evaluate and to confirm the horizontal and vertical isolation performance, rocking suppression performance, and the applicability of the this seismic isolation system as the combined system. 4 rolling seal type air springs and 4 hydraulic load-carrying cylinders with rocking suppression devices supported the weight. As a result, the proposed system was verified that it could be applied to the actual nuclear power plant building to be target.

LBB Under Beyond Design Basis Seismic Loading

2012 ◽  
Author(s):  
Tao Zhang ◽  
Frederick W. Brust ◽  
Gery Wilkowski ◽  
Heqin Xu ◽  
Alfredo A. Betervide ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Seismic Event ◽  
Jet Impingement ◽  
Seismic Loading ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Plant Design ◽  
Piping Systems ◽  
Heavy Water Reactor ◽  
Regulatory Commission

The Atucha II nuclear power plant is a unique pressurized heavy water reactor (PHWR) being constructed in Argentina. The original plant design was by Kraftwerk Union (KWU) in the 1970’s using the German methodology of break preclusion. The plant construction was halted for several decades, but a recent need for power was the driver for restarting the construction. The US NRC developed leak-before-break (LBB) procedures in draft Standard Review Plan (SRP) 3.6.3 for the purpose of eliminating the need to design for dynamic effects that allowed the elimination of pipe whip restraints and jet impingement shields. This SRP was originally written in 1987 with a modest revision in 2005. The United States Nuclear Regulatory Commission (US NRC) is currently developing a draft Regulatory Guide on what is called the Transition Break Size (TBS). However, modeling crack pipe response in large complex primary piping systems under seismic loading is a difficult analysis challenge due to many factors. The initial published work on the seismic evaluations for the Atucha II plant showed that even with a seismic event with the amplitudes corresponding to the amplitudes for an event with a probability of 1e−6 per year, that a Double-Ended Guillotine Break (DEGB) was pragmatically impossible due to the incredibly high leakage rates and total loss of make-up water inventory. The critical circumferential through-wall flaw size in that case was 94-percent of the circumference. This paper discusses further efforts to show how much higher the applied accelerations would have to be to cause a DEGB for an initial circumferential through-wall crack that was 33 percent around the circumference. This flaw length would also be easily detected by leakage and loss of make-up water inventory. These analyses showed that the applied seismic peak-ground accelerations had to exceed 25 g’s for the case of this through-wall-crack to become a DEGB during a single seismic loading event. This is a factor of 80 times higher than the 1e−6 seismic event accelerations, or 240 times higher than the safe shutdown earthquake (SSE) accelerations.

Development of Three-Dimensional Seismic Isolation Technology for Next Generation Nuclear Power Plant Applications

2005 ◽  
Author(s):  
K. Takahashi ◽  
K. Inoue ◽  
M. Morishita ◽  
T. Fujita
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Scale Model ◽  
Isolation System ◽  
The Real ◽  
Reactor Building

Seismic isolation technology plays an important role in the area of architect engineering, especially in Japan where earthquake comes so often. This technology also makes the nuclear power plant rationalized. The horizontal base isolation with laminated rubber bearings has already been proven its effectiveness. These days, seismic isolation technology is expected to mitigate even the vertical load, which affects the structural design of primary components. Seismic isolation system has possibility to improve the economical situation for the nuclear power plant. From these points of view, a research project has been proceeded to realize practical three dimensional seismic isolation systems from 2000 to 2005 under the sponsorship of the Ministry of Economy, Trade and Industry of the Japanese government. The isolation system is developed for the supposed “Fast Breeder Reactor (abbreviated FBR)” of the next generation. Two types of seismic isolation systems are developed in the R&D project. One is a three-dimensional base isolation for a reactor building (abbreviated 3D SIS) and the other is a vertical isolation for main components with horizontal base isolation of the reactor building (abbreviated V. +2D SIS). At first step of the R&D, requirements and targets of development for the seismic isolation system were identified. Seismic condition for R&D was discussed based on the real seismic response. Vertical natural frequency and damping ratio required to the system were introduced from the response to the seismic movement. As for 3D SIS, several system concepts were proposed to satisfy the requirements and targets. Through discussions and tests on performance, reliability, applicability, maintainability, “Rolling seal type air spring system with hydraulic anti-rocking devices” was decided to be developed. Verification shaking tests with the 1/7 scale model of the system and analysis for applicability to the real plant are conducted. The result shows that the system is able to support the reactor building, to suppress the rocking motion and to mitigate the vertical seismic load. As for V.+2D SIS, coned disk spring device was selected at the beginning of R&D. Performance tests of the elements, which include common deck movement, were conducted and the system applicability to the plant is confirmed. Verification tests were conducted with 1/8 scale model of the system and the result proves the applicability to the real plant.

URANUS: Korean Lead-Bismuth Cooled Small Modular Fast Reactor Activities

2011 ◽  
Author(s):  
Sungyeol Choi ◽  
Il Soon Hwang ◽  
Jae Hyun Cho ◽  
Chun Bo Shim
Keyword(s):  
Fast Reactor ◽  
Nuclear Power ◽  
Base Isolation ◽  
Cooling System ◽  
Natural Circulation ◽  
High Level Waste ◽  
Isolation System ◽  
Base Isolation System ◽  
Enriched Uranium ◽  
Seismic Base Isolation

Since 1994, Seoul National University (SNU) has developed an innovative future nuclear power based on LBE cooling advanced Partitioning and Transmutation (P&T) approach that leaves no high-level waste (HLW) behind with transmutation reactor named as Proliferation-resistant, Environment-friendly, Accident-tolerant, Continual, and Economical Reactor (PEACER). A small modular lead-bismuth cooled reactor has been designated as Ubiquitous, Robust, Accident-forgiving, Nonproliferating and Ultra-lasting Sustainer (URANUS-40) with a nominal electric power rating of 40 MW (100 MW thermal) that is well suited to be used as a distributed power source in either a single unit or a cluster for electricity, heat supply, and desalination. URANUS-40 is a pool type fast reactor with and an array of heterogeneous hexagonal core, fueled by proven low-enriched uranium dioxide fuels. The primary cooling system is designed to be operated by natural circulation. 3D seismic base isolation system is introduced underneath the entire reactor building allowing an earthquake of 0.5g zero period acceleration (ZPA) for the Safe Shutdown Earthquake (SSE). Also, the proliferation risk can be effectively managed by capsulized core design and a long refueling period (25yr).

Sign in / Sign up

Export Citation Format

Share Document