Verification for a GEOSHIELD application to the SMART vessel fluence by a Monte Carlo simulation

In general the two dimensional discrete ordinates transport code DORT has been used for an evaluation of neutron and gamma fluxes during a shielding design of nuclear reactors. It is very complicated and it takes too much time for shielding designers to prepare input data such as a geometrical modeling and a source distribution and to process an output of the results from the shielding analysis. The GEOSHIELD code was developed to save the time spent preparing a geometrical model and an output processing. The GEOSHIELD code is composed of a module for a geometrical modeling by using a combinatorial geometry, a module for a fixed source redistribution, a module for a DORT processing, and a module for a graphical processing of the output activities. The evaluation of an irradiation of a fast neutron which has an energy of higher than 1.0 MeV is very important to verify the integrity of an internal structure including a pressure vessel. The GEOSHIELD code was applied to evaluate a fast neutron fluence distribution on the internal structures inside the reactor pressure vessel of the SMART reactor and the MCNP was used for verification of the result from the GEOSHIELD calculation. Result of the GEOSHIELD and MCNP showed good agreement each other.