Toshihiro Matsuoka

Experimental Study on Free Standing Rack Loading Full Fuel Assembly

The spent fuel storage rack of a nuclear plant stores the spent fuel temporarily before it can be moved to a reprocessing facility. Therefore, the spent fuel storage rack must have a high tolerance against large seismic loads. So, the free standing rack is developed in Japan as other countries. The free standing rack structure incorporates the effect of the friction force on the spent fuel pool floor, and the fluid effect.Under earthquake condition, the free standing rack sliding and rocking motions are induced and the spent fuels rattle in the cells.In this paper, sliding and rocking motions of full-scale rack model having full loading fuel assembly subjected to the seismic excitation are studied. To develop an analysis evaluation method for rack motions, we carried out seismic test of a full-scale rack model using a shaking table, and obtained the fundamental data about the free standing rack.Copyright

Experimental Parameter Study on Free Standing Rack

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. Sliding and rocking motions of full-scale rack model having full loading fuel assembly subjected to the seismic excitation are studied [1]. We carried out the seismic test of the free standing rack under some conditions. The distribution of the fuel assembly affects the sliding and rocking motions of the rack, and the outer plate reduces the rack response level by fluid effect. We made sure of them by seismic experiment using a shaking table.In this paper, sliding and rocking motions of full-scale rack model under some conditions are studied. To develop an analysis evaluation method of the rack sliding and rocking motions, we obtained the fundamental data about the free standing rack by seismic test using a shaking table.© 2012 ASME

Application of Master Curve Method to Fracture Toughness Estimation of the Transport and Storage Cask Material

The transportation and storage casks have to be designed by considering transport and handling accidents. IAEA safety standard [1] requires drop test using a scale model and demonstration of structural integrity of the cask container vessel from the view point of leakage and instable fracture. For the fracture evaluation, it has to be verified that brittle fracture does not occur at the lowest temperature −40degC. MHI has developed the MSF-57BG cask whose body is made of forged low alloy steel LF3-m. It is well known that low alloy steel has the brittle-to-ductile transition temperature range of fracture toughness and large scatter of toughness value in this region. For the cask’s integrity evaluation, it is needed to obtain the fracture toughness dependent on temperature of this material by considering data scatter. The Master curve procedure [2] was proposed for estimation of fracture toughness of the pressure vessel on the basis of statistical procedure by using relatively small number of specimens. This paper examined the determination method of fracture toughness considering dynamic loading effect and data scatter in the brittle-to-ductile transition temperature by using the Master curve procedure.Copyright

Experimental and Analysis Study of Free Standing Rack Under Seismic Excitation

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 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.We carried out seismic experiments on the full-scale rack model in water and dry conditions to obtain the fundamental data about free standing rack (sliding, rocking and turning motions). We have developed the nonlinear dynamic analysis method to predict seismic response for the free standing rack utilizing the full-scale test result and verified the analysis evaluation method of the rack by comparison of test result.Copyright