Research on the influencing factors of radionuclide fractionation in surface nuclear explosions

Abstract

Fractionation plays an important role in the distribution of radioactive isotopes on particles formed in a nuclear explosion. This study examines the variables that affect radionuclide fractionation in surface nuclear explosions, including nuclear explosion yield, nuclear charge, solidification temperature, solidification time, and geological condition. The distribution of radionuclides is calculated using the improved Freiling radial-distribution model and the Bateman equation to describe radionuclide decay. Quantitative analysis is conducted to examine the impact of various influencing factors on the total β radioactivity. Specifically, the mass chains 89 and 137, as well as mass chains 95 and 144, which represent the radioactive surface and volume distributions are investigated respectively. The results show that the total $\beta$ radioactivity increases as the explosion yield increases and as the solidification temperature decreases, and increases slightly as the solidification time increases. The radioactivity will concentrate more on the larger size particles under harder geological conditions. The influencing factors have greater impacts on the radioactive volume distributions than on the surface distributions, and the variations in distinct mass chains under the same influencing factors are inconsistent. Overall, the solidification temperature and the geological condition have significant impacts on the distribution of particle radioactivity, followed by the effects of explosion yield and nuclear charge. The distribution of particle radioactivity is not significantly affected by the solidification time.