Seismic Analyses Of Double Vessels In Lead-Bismuth Fast Reactors

Nuclear energy is a super candidate to solve the environmental issues in energy-shortage and ever-deteriorating pollutions. However, how to deal with nuclear waste and how to utilize the uranium fuel effectively have turned to be other problems. The develoment of fast reactors is expected to solve these problems, especially the lead-bismuth fast reactor which has attracted broad attention due to its high security and superior ability in shielding gamma-rays.Among the various equipment in nuclear power plants, the reactor core is the most important and dangerous device which is protected by the reactor vessel. As for the lead-bismuth fast reactor, the inner radioactive substances will never leak unless the vessel breaks down. Therefore, it is very necessary to conduct seismic resistance analysis of the lead-bismuth fast reactor vessel.This paper first comparatively studied the material properties of lead-bismuth coolant and other coolants, and then investigated the displacement, stress and strain response of the lead-bismuth coolant in two different loops. Then, a double-layer guard vessel model was designed and its response to mechanical stress was analyzed. The results indicated that the maximum displacement took place at the lower head of the vessel while the maximum stress strain appeared at the joint between the lower head and the lower tube section. Next, the model analysis of the double-layer lead-bismuth faster reactor vessel was carried out, through which the inherent frequency of the guard vessel within the seismic frequency range was obtained. In addition, this paper also studied the displacement, stress and strain response of the double-layer lead-bismuth faster reactor vessel under 9 °and 0-40 Hz based on the harmonic response analysis. The results showed that the security of the double-layer lead-bismuth faster reactor vessel decreased. Finally, through the analysis of the acceleration response spectrum, the seismic resistance of the double-layer lead-bismuth faster reactor vessel was carried out.