Patent ID: 7233888

Claim:
A computer-implemented method for simulating three-dimensional spatial distributions of neutron and gamma fluences in a nuclear reactor, the reactor comprising a reactor pressure vessel, a reactor core surrounded by a core shroud positioned in the reactor pressure vessel, said method comprising: generating a detailed geometric configuration of a nuclear reactor core and surrounding components; generating a detailed fuel composition distribution; calculating three-dimensional nuclide concentrations for the fuel rods and the water surrounding the fuel rods using the generated geometric configuration and generated fuel composition distribution; calculating neutron and gamma fluxes using a Monte Carlo radiation transport criticality mode methodology; calculating neutron and gamma fluences at points outside the core; and generating neutron and gamma fluence maps for predetermined areas of the reactor based on the calculated neutron and gamma fluxes and the calculated neutron and gamma fluences at points outside the core; and displaying the fluence maps; wherein calculating neutron and gamma fluences at points outside the core comprises: calculating neutron and gamma fluxes using the Monte Carlo radiation transport criticality mode methodology; saving a surface source based on the core periphery; and calculating neutron and gamma fluxes using a Monte Carlo radiation transport fixed-source mode methodology based on the surface source using an adequate number of sampling histories to obtain a predetermined level of convergence.