Monte Carlo Study Of Ambient Dose Equivalent Of Photon Outside Mode 30B Cylinder

Along with the national nuclear power construction and development, the inevitable need mining more nuclear power resources, accelerate the turnover of nuclear materials. Uranium hexafluoride is the basis of nuclear material, is widely used in U-235 enrichment. The vessel filled uranium hexafluoride is a source of radiation due to uranium hexafluoride containing radionuclide. Therefore, the problem of external radiation protection for uranium hexafluoride transport vessel is unavoidable.Model 30B cylinder is selected to study photon ambient dose equivalent outside of uranium hexafluoride transport vessel due to its most widely applied. This paper studies the radiation level surface of uranium hexafluoride transport container related domestic and international rules and guidelines, and the current research situation of radiation level out surface of model 30 B cylinder. EGSnrc Monte Carlo is used to simulation photon mass attenuation coefficient of with photon energy 50 keV to 3 MeV for uranium hexafluoride and16 MnDr,is used to calculation the build up factor of photon ambient dose equivalent for uranium hexafluoride and16 MnDr with thickness of 0.5 mean free path(mfp) to 10 mfp. The conversion coefficients of the single photon with energies from 50 keV ~ 3 MeV to ambient dose equivalent outside model 30 B cylinder is given by numerical methode, which is based on the data obtained by EGSnrc monte carlo code. At the same time, the photon mass attenuation coefficient obtained by EGSnrc monte carlo code and the conversion coefficients got by numerical methode are verified by using the National Institute of Standard and Technology database, MCNP and FLUKA monte carlo code separately. The results of verification show the EGSnrc simulation results are reasonable, reliable and accurate. Finally, the conversion coefficients of U-234, U-235, U-238 and modern progeny in to ambient dose equivalent rate of photon, the ambient dose equivalent rate of photon outside of model 30 B cylinder change as the stored time, and the ambient dose equivalent rate of photon outside of empty model 30 B cylinder change as the time are given. Through this study, the method of obtaining ambient dose equivalent rate of photon outside mode 30 B cylinder is feasible, relatively fast. The results and method of this paper can be used to evaluate the ambient dose equivalent rate of photon of model 30B cylinder and other model vessel.