MONTE-CARLO CALCULATION OF DELAYED GAMMA DOSE-RATE IN COMPLEX-GEOMETRY USING THE CONCEPT OF EFFECTIVE DELAYED GAMMA PRODUCTION CROSS-SECTION

With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed gamma transport equations take the same form as the coupled neutron-prompt gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the flux coupling step required in conventional calculations and makes it easier to handle complex, multidimensional problems, especially those that call for Monte Carlo calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method is complex geometry are illustrated by its application in the Monte Carlo solution of a practical design problem.