Evaluation Technique on the BWR Turbine Skyshine Analysis Based on the MCNP-Line Beam Response Coupled Method

A refinement of a simplified QAD-SKYSHINE calculation for gamma-rays skyshine emitted from a turbine building of nuclear power plant is performed by the hybrid method using the MCNP Monte Carlo code. In this method, a detailed Monte Carlo transport calculation is firstly used to determine the energy and emission angle of an crossing point of the gamma-rays through the turbine building wall into atmosphere. Then, the computationally efficient integral Line-Beam method is used to transport gamma-ray from this pseudosource to the distant location at which the skyshine dose is to be calculated. Where, the Line-Beam response functions are generated by the MCNP and fitted to the four-parameter formula. The present developed method is able to estimate precisely skyshine dose within short time.