Reactivity integral transport theory formulations

Many methods and computer codes have been developed for the solution of Eq. (47) for the purpose of reactivity calculations. The majority of them are based on integral transport theory formulations. They include the methods of Karam et al. (20), Collins and Palmer (27), Kier and Salvatores (22,23), McGrath and Foell (24), Fischer (25), Oosterkamp (26), and McGrath and Fischer (27). 

Interest in integral transport theory methods for reactivity calculations has recently increased, mainly because of two features peculiar to integral formulations. 

The collision probability is one of several possible formulations of integral transport theory. Three other formulations are the integral equations for the neutron flux, neutron birth-rate density, and fission neutron density. Oosterkamp (26) derived perturbation expressions for reactivity in the birth rate density formulation. The fission density formulation provides the basis for Monte Carlo methods for perturbation calculations (52, 55). 

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