Underground Nuclear Explosions Produce <sup> 37 </ Sup> Ar Numerical Simulation Of Transport To The Surface

Monitoring radioactive noble gas ³⁷Ar is an important technique method for the On-site Inspection(OSI) of the Comprehensive Nuclear Test Ban Treaty (CTBT) verification regime.In order to establish a theoretical model to calculate the appearing time and radioactivity which ³⁷Ar transports to the ground after a nuclear explosion, we first consider the situation where fission products are completely sealed within the cavity after the nuclear underground explosion. The rock media in the test area is assumed to be homogeneous porous media, without consideration of gas adsorption by and release from the rock media. The seepage model in the porous media is used to calculate ³⁷Ar transportation.Secondly, we consider the situation where the rock media can't seal fission products completely within the cavity and fracture networks are formed in the underground. We consider the noble gas generated by the underground nuclear explosion, transporting to the surface of the ground though the fracture network. So we use Fracture Network Model to calculate the process of ³⁷Ar transportation.Computational results give the time ³⁷Ar leaks to the surface of the ground and the variation of its radioactivity with time. We could analyze and use the result in developing OSI noble gas monitoring systems and evaluating their effectiveness in use.