Application of a 3D Discrete Ordinates Program in Heating Rate Calculation for CAP1400 Nuclear Power Plant Internals

The heating rate of CAP1400 reactor internals is calculated with 3D discrete coordinate（SN） program（TORT）, and the results are compared and verified with the results of MCNP and DORT. The problem solved in the reactor shielding design is fixed-source problem, SORCERY（developed by the Westinghouse company） is used to transfer the core power distribution（pin by pin） to 3D source distribution. Because of the large CAP1400 reactor model, a great deal of computer resources will be expended in the production of 3D fixed source, and the limit of array dimensions in SORCERY will be exceeded, so, another auxiliary program PSOR is developed. And TORT could be used in the CAP1400 large scale problem.