NUMERICAL-SOLUTION OF BATEMAN SYSTEMS

A numerical approach to the solution of Bateman systems is described. The procedure uses either of two algorithms to compute the Bateman pro pagator and provides a reliable estimate of its accuracy. The approach affords the treatment of complete decay chains of radionuclides. By c omputing the evolution of the neptunium series inventory in used CANDU (TM) fuel, it is demonstrated that both the proposed method and that o f the ORIGEN code in its depletion aspects are mutually validating. Th e procedure presented is well-suited to the efficient and accurate eva luation of evolving radionuclide inventories originating from arbitrar y initial states and is both readily incorporated into models of radio nuclide transport from a geologic nuclear waste repository and extendi ble to allow the calculation of nuclide inventory generation in fuel, reactor components and systems.