Experiments on fluid-structure interaction dynamic response of a new free-standing spent fuel storage basket

Abstract

Spent fuel from nuclear power plants is usually stored in specific equipment in spent fuel pools. To improve the efficiency of spent fuel transportation, a new free-standing spent fuel storage basket has been developed. In the event of an earthquake, the spent fuel storage baskets may collide with each other. If the spent fuel baskets break, this could lead to a leak of radiative materials. As the spent fuel is stored in high density in the spent fuel pool, the spent fuel leak may also lead to re-criticality. In addition, the fluid has a strong fluid-structure interaction with the baskets and the fuel assemblies. Therefore, it is very important to make the dynamic response of the baskets within the safe range under earthquake. To ensure the safety of the spent fuel storage baskets, the baskets need to be tested by a shaker in advance. During the scale analysis of the shaking table tests, there are two similarity laws, namely, a velocity-similarity law (Cv = 1) and an acceleration-similarity law (Ca = 1). However, there are some debates on which similarity law to obey in the complex phenomenon of baskets' seismic response. To solve the above problem, a series of 1/2 scale-down tests were carried out to investigate the response of the baskets. By the sine beat-wave tests, we obtain the friction coefficient between the spent fuel storage baskets and the pool, and the sliding and rocking patterns. Moreover, we carry out seismic shaking table tests on freestanding spent fuel storage baskets with different similarity laws. By observing the movement of the basket at different water levels of the working conditions, it is found that the fluid decreases the new basket's rocking amplitudes but increases the sliding amplitudes. The experiment can be the benchmark for the seismic analysis of spent fuel storage baskets.