Seismic Design of Free Standing Racks in Japanese Nuclear Power Plants

2017 ◽  
Author(s):  
Yu Takaki ◽  
Katsuhiko Taniguchi ◽  
Junichi Kishimoto ◽  
Akihisa Iwasaki ◽  
Yoshitsugu Nekomoto ◽  
...  
Keyword(s):  
Seismic Design ◽  
Nuclear Power ◽  
Power Plants ◽  
Design Method ◽  
Seismic Resistance ◽  
Spent Fuel ◽  
Analysis Model ◽  
Free Standing ◽  
Scale Free ◽  
Seismic Design Method

The free standing racks are spent fuel storage racks with self-sustained structure without fixation to the pit floor or pit walls. If a free standing rack receives a force to move it due to an earthquake, the force acting on each member of the rack is reduced in compared to the floor-anchored racks owing to sliding of the free standing rack. Now it is planned to exchange the existing floor-anchored racks with the free standing racks to secure higher seismic resistance. In previous studies, efforts were made to establish a behavior analysis model that allows for evaluation of sliding and rocking behaviors of free standing racks and to make out a seismic design method based on an evaluation technique to evaluate, in a conservative manner, vibration test results of full-scale free standing racks. The free standing racks which consist of connected eight racks are designed with this seismic design method. It was confirmed that the free standing racks have enough seismic resistance by performing evaluation using the basic seismic motion and making an analysis on beyond the design event.

Development of Seismic Design Method for Free Standing Rack

2013 ◽  
Author(s):  
Akihisa Iwasaki ◽  
Yoshitsugu Nekomoto ◽  
Hideyuki Morita ◽  
Katsuhiko Taniguchi ◽  
Daisaku Okuno ◽  
...  
Keyword(s):  
Seismic Design ◽  
Seismic Analysis ◽  
Design Method ◽  
Spent Fuel ◽  
Free Standing ◽  
Highly Nonlinear ◽  
Spent Fuel Pool ◽  
Vibration Tests ◽  
Seismic Design Method ◽  
Complex Phenomena

For high earthquake resistance and ease of installation, free standing racks which are not anchored to the pool floor or walls has been adopted in many countries. Under the earthquake, the response of the free standing rack is highly nonlinear and involves a complex combination of motions (sliding, rocking, twisting, and turning) and impacts between the fuel assemblies and the fuel cell walls, rack-to-rack, and the pit floor and the rack pedestals. To obtain an accurate simulation of the free standing rack, the seismic analysis requires careful considerations of these complex phenomena (sliding, rocking, twisting, and turning), fluid coupling effects and frictional effects. The important evaluation items while applying the free standing rack to the actual nuclear plants are maximum sliding displacement of the rack, maximum rocking displacement and maximum leg load under earthquake. When the sliding displacement increases, the rack may collide against the spent fuel pool wall. In addition, the free standing rack should not exhibit tilt sufficient to cause to the rack to overturn. The vibration tests were conducted in order to predict the rack behavior under earthquake, and the analysis method was validated by comparison to tests results. Furthermore, we developed the seismic design method to obtain the margin of safety for free standing rack.

Analysis Study on Free Standing Rack Under the Earthquake Excitation

2012 ◽  
Author(s):  
Akihisa Iwasaki ◽  
Yoshitsugu Nekomoto ◽  
Hideyuki Morita ◽  
Katsuhiko Taniguchi ◽  
Daisaku Okuno ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Response Analysis ◽  
Analysis Method ◽  
Spent Fuel ◽  
Analysis Model ◽  
Free Standing ◽  
Earthquake Excitation ◽  
Scale Free ◽  
Seismic Experiment ◽  
Test Result

The spent fuel rack of a nuclear plant stores the spent fuel temporarily before it can be moved to a reprocessing facility. Therefore, the spent fuel rack must have a high tolerance against big seismic loads. So, the free standing rack is developed in Japan as other countries. To develop an analysis evaluation method for the free standing rack motions, we carried out seismic experiment of the full-scale free standing rack to obtain the fundamental data about it. The free standing rack motions are sliding and rocking under seismic excitation. To evaluate the sliding and rocking motions of the free standing rack, we reflected test result to analysis method, and developed the dynamic response analysis model.

Calculation of Seismic Resistance of Group «B» Cranes Operating at Nuclear Power Plants (NPP)

2018 ◽  
Vol 12 (3) ◽  
pp. 73-80
Author(s):  
Y.I. Pimchin ◽  
V.A. Naugolnov ◽  
G.A. Naumenko ◽  
I.U. Pimchin
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Seismic Resistance ◽  
Group B

Seismic Design Method for Hybrid Viaduct in Japanese Railways

2000 ◽  
Vol 16 (20) ◽  
pp. 338-346
Author(s):  
Kiyomitsu MURATA ◽  
Masato YAMADA ◽  
Tomohiro TAKAYAMA ◽  
Masanori KINOSHITA
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Seismic Design Method

Research Situation on the Performance-Based Seismic Design Method for Reinforced Concrete Structure

2010 ◽  
Vol 163-167 ◽  
pp. 1757-1761
Author(s):  
Yong Le Qi ◽  
Xiao Lei Han ◽  
Xue Ping Peng ◽  
Yu Zhou ◽  
Sheng Yi Lin
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Design Method ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Seismic Evaluation ◽  
Seismic Codes ◽  
Performance Based Seismic Design ◽  
Capacity Calculation ◽  
Seismic Design Method

Various analytical approaches to performance-based seismic design are in development. Based on the current Chinese seismic codes，elastic capacity calculation under frequent earthquake and ductile details of seismic design shall be performed for whether seismic design of new buildings or seismic evaluation of existing buildings to satisfy the seismic fortification criterion “no damage under frequent earthquake, repairable under fortification earthquake, no collapse under severe earthquake”. However, for some special buildings which dissatisfy with the requirements of current building codes, elastic capacity calculation under frequent earthquake is obviously not enough. In this paper, the advanced performance-based seismic theory is introduced to solve the problems of seismic evaluation and strengthening for existing reinforced concrete structures, in which story drift ratio and deformation of components are used as performance targets. By combining the features of Chinese seismic codes, a set of performance-based seismic design method is established for reinforced concrete structures. Different calculation methods relevant to different seismic fortification criterions are adopted in the proposed method, which solve the problems of seismic evaluation for reinforced concrete structures.

scholarly journals Seismic Design Method for CFS Diagonal Strap-Braced Stud Walls: Experimental Validation

2016 ◽  
Vol 142 (3) ◽  
pp. 04015154 ◽  
Author(s):  
Luigi Fiorino ◽  
Ornella Iuorio ◽  
Vincenzo Macillo ◽  
Maria Teresa Terracciano ◽  
Tatiana Pali ◽  
...  
Keyword(s):  
Seismic Design ◽  
Experimental Validation ◽  
Design Method ◽  
Seismic Design Method

NUCLEAR WASTE MANAGEMENT IN SPAIN: ANALYSIS OF THE CURRENT SITUATION AND ALTERNATIVE STRATEGIES

10.6036/10156 ◽  
2021 ◽  
Vol 96 (4) ◽  
pp. 355-358
Author(s):  
Pablo Fernández Arias ◽  
DIEGO VERGARA RODRIGUEZ
Keyword(s):  
Nuclear Waste ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Fuel ◽  
Nuclear Waste Storage ◽  
Alternative Strategies ◽  
Temporary Storage ◽  
Long Term Storage ◽  
High Level

Centralized Temporary Storage Facility (CTS) is an industrial facility designed to store spent fuel (SF) and high level radioactive waste (HLW) generated at Spanish nuclear power plants (NPP) in a single location. At the end of 2011, the Spanish Government approved the installation of the CTS in the municipality of Villar de Cañas in Cuenca. This approval was the outcome of a long process of technical studies and political decisions that were always surrounded by great social rejection. After years of confrontations between the different political levels, with hardly any progress in its construction, this infrastructure of national importance seems to have been definitively postponed. The present research analyzes the management strategy of SF and HLW in Spain, as well as the alternative strategies proposed, taking into account the current schedule foreseen for the closure of the Spanish NPPs. In view of the results obtained, it is difficult to affirm that the CTS will be available in 2028, with the possibility that its implementation may be delayed to 2032, or even that it may never happen, making it necessary to adopt an alternative strategy for the management of GC and ARAR in Spain. Among the different alternatives, the permanence of the current Individualized Temporary Stores (ITS) as a long-term storage strategy stands out, and even the possibility of building several distributed temporary storage facilities (DTS) in which to store the SF and HLW from several Spanish NPP. Keywords: nuclear waste, storage, nuclear power plants.

scholarly journals Temperature conditions in the RBMK spent fuel pool in the event of disturbances in its cooling mode

2021 ◽  
Vol 7 (1) ◽  
pp. 9-13
Author(s):  
David A. Hakobyan ◽  
Victor I. Slobodchuk
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Maximum Temperature ◽  
Spent Fuel ◽  
Cooling Mode ◽  
Temperature Conditions ◽  
Fuel Assemblies ◽  
Spent Fuel Pool

The problems of reprocessing and long-term storage of spent nuclear fuel (SNF) at nuclear power plants with RBMK reactors have not been fully resolved so far. For this reason, nuclear power plants are forced to search for new options for the disposal of spent fuel, which can provide at least temporary SNF storage. One of the possible solutions to this problem is to switch to compacted SNF storage in reactor spent fuel pools (SFPs). As the number of spent fuel assemblies (SFAs) in SFPs increases, a greater amount of heat is released. In addition, no less important is the fact that a place for emergency FA discharging should be provided in SFPs. The paper presents the results of a numerical simulation of the temperature conditions in SFPs both for compacted SNF storage and for emergency FA discharging. Several types of disturbances in normal SFP cooling mode are considered, including partial loss of cooling water and exposure of SFAs. The simulation was performed using the ANSYS CFX software tool. Estimates were made of the time for heating water to the boiling point, as well as the time for heating the cladding of the fuel elements to a temperature of 650 °С. The most critical conditions are observed in the emergency FA discharging compartment. The results obtained make it possible to estimate the time that the personnel have to restore normal cooling mode of the spent fuel pool until the maximum temperature for water and spent fuel assemblies is reached.

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