Seismic Isolation of the IRIS Nuclear Plant

2009 ◽  
Author(s):  
Massimo Forni ◽  
Alessandro Poggianti ◽  
Fosco Bianchi ◽  
Giuseppe Forasassi ◽  
Rosa Lo Frano ◽  
...  
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Wide Spectrum ◽  
Seismic Excitation ◽  
Fragility Analysis ◽  
Pressurized Water ◽  
Isolation System ◽  
Order Of Magnitude ◽  
Safety Features ◽  
The Impact

The safety-by-design™ approach adopted for the design of the International Reactor Innovative and Secure (IRIS) resulted in the elimination by design of some of the main accident scenarios classically applicable to Pressurized Water Reactors (PWR) and to the reduction of either consequences or frequency of the remaining classical at-power accident initiators. As a result of such strategy the Core Damage Frequency (CDF) from at-power internal initiating events was reduced to the 10−8/ry order of magnitude, thus elevating CDF from external events (seismic above all) to an even more significant contributor than what currently experienced in the existing PWR fleet. The same safety-by-design™ approach was then exported from the design of the IRIS reactor and of its safety systems to the design of the IRIS Nuclear Steam Supply System (NSSS) building, with the goal of reducing the impact of seismically induced scenarios. The small footprint of the IRIS NSSS building, which includes all Engineered Safety Features (ESF), all the emergency heat sink and all the required support systems makes the idea of seismic isolation of the entire nuclear island a relatively easy and economically competitive solution. The seismically isolated IRIS NSSS building dramatically reduces the seismic excitation perceived by the reactor vessel, the containment structure and all the main IRIS ESF components, thus virtually eliminating the seismic-induced CDF. This solution is also contributing to the standardization of the IRIS plant, with a single design compatible with a variety of sites covering a wide spectrum of seismic conditions. The conceptual IRIS seismic isolation system is herein presented, along with a selection of the preliminary seismic analyses confirming the drastic reduction of the seismic excitation to the IRIS NSSS building. Along with the adoption of the seismic isolation system, a more refined approach to the computation of the fragility analysis of the components is also being developed, in order to reduce the undue conservatism historically affecting seismic analysis. The new fragility analysis methodology will be particularly focused on the analysis of the isolators themselves, which will now be the limiting components in the evaluation of the overall seismic induced CDF.

scholarly journals Comparative analysis of conventional and new seismically isolated structure

2021 ◽  
Vol 64 (3) ◽  
pp. 185-193
Author(s):  
Jelena Ristić ◽  
Miloš Vučinić ◽  
Danilo Ristić ◽  
Milutin Vučinić
Keyword(s):  
Seismic Isolation ◽  
Low Cost ◽  
Seismic Energy ◽  
Seismic Excitation ◽  
Isolation System ◽  
Vibration Period ◽  
International Projects ◽  
Dominant Period ◽  
Efficient Protection ◽  
Seismically Isolated

Extensive analytical and experimental research has been done by the authors directed to mitigation of the effects of earthquakes on structures. The research results mainly represent parts of the realized several related international projects. A selected part of the analytical studies directed to comparison between conventional and seismically isolated frame structures is presented in this paper. The responses of the applied newely developed advanced seismic isolation system HC-RMS-GOSEB to the simulated input excitation of three representative earthquakes of intensity 0.50g, have shown that it is very effective for construction of vibro-isolated and seismically resistant buildings, providing activated multistage seismic response and globally optimized seismic energy balance. Its application achieves an increase in the vibration period of the structure, far enough from the dominant period of seismic excitation. The results of the research confirm that this system is a potential solution for achieving low-cost and highly efficient protection of buildings.

Seismic Analysis of a Turbine on a Spring Isolated Pedestal

2006 ◽  
Author(s):  
Victor V. Kostarev ◽  
Andrei V. Petrenko ◽  
Peter S. Vasilyev ◽  
Alexander S. Lisyansky
Keyword(s):  
High Speed ◽  
Seismic Isolation ◽  
System Analysis ◽  
Seismic Analysis ◽  
Full Range ◽  
Coupled Model ◽  
Time History ◽  
Soil Conditions ◽  
Isolation System ◽  
Detailed Model

Paper deals with the detailed seismic analysis of powerful high-speed Russian turbine of Nuclear Power Plant. Dozens of patterns of such turbine work reliably since 70’s worldwide. Until last decade only simplified structural analyses were available due to a complicated overall structure and internals of such turbines. The current analysis considers detail geometry of the turbine itself as well as vibration and seismic isolation system within turbine’s pedestal and full range of operational, accident and seismic loads. To solve the problem of the turbine seismic and dynamic qualification the following steps have been done. On the first step detailed finite element models of turbine’s high and low pressure parts and rotor system with bearings were created. Using such models corresponding simplified models were developed to be included into the coupled model of the system: “Building – Vibroisolation Pedestal – Turbine” (BVT). The second step was the analysis of that coupled system. Soil-structure interaction was considered using actual soil conditions. Three components of time history acceleration were used to define seismic excitation. As the result of BVT system analysis a full picture of time history displacements and loads were determined. At the same time a non-linear problem of rotor’s axial and radial bearings behavior and gaps in the system was solved. On the final step determined loads were applied to the detailed model of turbine for seismic and dynamic qualification of the whole structure.

Study on Seismic Analysis Method of Fast Reactor Plant with Seismic Isolation System

2020 ◽  
Vol 2020 (0) ◽  
pp. S10107
Author(s):  
Shigeki OKAMURA ◽  
Takahiro KINOSHITA ◽  
Hiroyuki NISHINO ◽  
Hidemasa YAMANO ◽  
Kenichi KURISAKA ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Seismic Isolation ◽  
Seismic Analysis ◽  
Analysis Method ◽  
Reactor Plant ◽  
Isolation System

Seismic Isolation for Advanced Nuclear Power Stations

1990 ◽  
Vol 6 (2) ◽  
pp. 371-401 ◽  
Author(s):  
Frederick F. Tajirian ◽  
James M. Kelly ◽  
Ian D. Aiken
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Three Dimensional ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Isolation System ◽  
Power Stations ◽  
Safety Margins ◽  
Extensive Test ◽  
The U.S

Seismic isolation offers an attractive approach for reducing seismic loads in nuclear structures, and more significantly, in reactor components. Isolation will lead to a simplification of designs, facilitate standardization, enhance safety margins, and may potentially reduce cost. To date, six large Pressurized Water Reactor units have been isolated in France and South Africa and several advanced nuclear concepts in the U.S., Japan, and Europe have incorporated this approach. It is recognized that to qualify and license an isolation system in the U.S. and in Japan, a comprehensive testing program of isolation components and systems would be required. A major seven year program was initiated in Japan in 1987 with the objective of establishing a qualified seismic isolation design for a large fast breeder reactor to be constructed at the end of this decade. In the U.S., two concepts which use steel laminated elastomeric bearings for seismic isolation have been developed. One of these concepts is a novel system which provides three-dimensional isolation. An extensive test program of scaled prototype bearings to demonstrate their feasibility and effectiveness has been carried out.

Dynamic Buckling of 50000m3 Vertical Storage Tanks under Seismic Excitation

2013 ◽  
Vol 353-356 ◽  
pp. 2039-2042
Author(s):  
Sun Ying ◽  
Jian Gang Sun ◽  
Li Fu Cui
Keyword(s):  
Storage Tank ◽  
Numerical Solutions ◽  
Base Isolation ◽  
Three Dimensional ◽  
Dynamic Buckling ◽  
Seismic Excitation ◽  
Storage Tanks ◽  
Isolation System ◽  
Base Isolation System ◽  
The Impact

To study the dynamic buckling characteristics of storage tank subjected to three-dimensional seismic excitation, selecting 50000m3 large vertical floating roof storage tanks as research object, the base isolation system was introduced and allowing for the impact of floating roof. The finite element models of non-isolation and base isolation storage tank were established respectively by ADINA. The seismic responses of these two types of storage tank were calculated and the numerical solutions were compared. The results indicate that the dynamic buckling modes of these two types of storage tank system belong to plastic buckling; base isolation measure can effectively increase the critical load value of dynamic buckling and plasticity yielding, the improve rates up to 38% and 60% respectively. The effectiveness of the base isolation can be verified from the angle of buckling.

A hybrid seismic isolation system toward more resilient structures: Shaking table experiment and fragility analysis

2021 ◽  
Vol 38 ◽  
pp. 102194
Author(s):  
Zoran Rakicevic ◽  
Aleksandra Bogdanovic ◽  
Ehsan Noroozinejad Farsangi ◽  
Abbas Sivandi-Pour
Keyword(s):  
Seismic Isolation ◽  
Shaking Table ◽  
Fragility Analysis ◽  
Isolation System

scholarly journals THE IMPACT OF APPLYING BASE ISOLATOR IN HOSPITAL BUILDING

2014 ◽  
Vol 10 (2) ◽  
pp. 9
Author(s):  
Predaricka Deastra ◽  
Jati Sunaryati ◽  
Riza Aryanti
Keyword(s):  
Seismic Performance ◽  
Seismic Isolation ◽  
Relative Displacement ◽  
Internal Force ◽  
Isolation System ◽  
Vibration Period ◽  
Final Project ◽  
The Difference ◽  
Earthquake Zone ◽  
The Impact

Due to Indonesia’s location in the earthquake zone, it is necessary for civil engineers in Indonesia to study seismic performance of a building, which is strongly related to the structure of the building itself. Buildings equipped with vibration damping structures, known as an isolation system, will have a different seismic behavior than if it did not have one. This is due to the impact of an earthquake dampening vibration isolator. This final project analyzes the difference between seismic performance of a building using a seismic isolation system and ones without. The conclusion of this final project shows that the isolation system will decrease the internal force of a structure element by about 57.71% for axial force, 84.10% for shear, and 85.75% for moment. The application of an isolation system will also decrease the relative displacement by about 74,28% and extended structure vibration period by about 171.17 %. Keywords: earthquake, seismic performance, isolation system.

scholarly journals Application of Seismic Isolation to the STAR-LM Reactor

2002 ◽  
Author(s):  
B. Yoo ◽  
R. F. Kulak
Keyword(s):  
Seismic Isolation ◽  
Design Research ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Base System ◽  
Two Dimensional ◽  
Isolation System ◽  
Fixed Base ◽  
Initial Work ◽  
Isolation Systems

This paper presents findings from our initial work in developing a seismic isolation system for the STAR-LM reactor design. Research and development was carried out to determine the characteristics of the isolator device. The heavy weight and small footprint presented a challenge in bearing design and bearing placement. Results are also presented from a study on the use of three-dimensional seismic isolation devices to the full-scale reactor. Both two-dimensional (i.e., one device for horizontal isolation only) and integral (i.e., one device for horizontal and vertical) concepts were explored. The seismic analysis responses of the two-dimensional and the three-dimensional isolation systems for the STAR-LM are compared with that of the conventional fixed base system. Finally, results are presented from a study on the effects of the levels of vertical and horizontal damping on the seismic response of STAR-LM.

Seismic Analysis of Conventional and Isolated LNG Tanks Using Mechanical Analogs

2008 ◽  
Vol 24 (3) ◽  
pp. 599-616 ◽  
Author(s):  
Ioannis P. Christovasilis ◽  
Andrew S. Whittaker
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Numerical Models ◽  
Base Shear ◽  
Isolation System ◽  
Analysis And Design ◽  
Mechanical Analog ◽  
Wave Heights ◽  
Overturning Moment ◽  
Lng Tank

The seismic response of a conventional and an isolated vertical, cylindrical, Liquefied Natural Gas (LNG) tank is computed using a mechanical analog and a finite element code to judge the utility of the analog for preliminary design and of the effectiveness of seismic isolation. Data reported and statistically sorted include base shear, global overturning moment, and wave height in the tank. The results obtained from the two numerical models are in good agreement and demonstrate that the mechanical analog can be used with confidence for the preliminary analysis and design of conventional and isolated LNG tanks that have similar dimensions to the sample tank of this study. The base shear and overturning moment in the seismically isolated LNG tank are 10% to 15% of the values computed for the conventional tank; the wave heights are unaffected by the introduction of a seismic isolation system.

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