The recovery procedure of pin-by-pin fields of power distribution in the core of VVER type reactor for the program BIPR-8. Verification calculations

Reconstruction of power distribution gives a means to check the compliance with design limits in steady-state calculations and to take account of power distribution deformation from one fuel element to another in transient calculations with use of spatial kinetics model. In calculation of reactivity accidents, its application makes it possible to avoid the additional conservatism derived from nodal calculation of power distributions. The resulting description of distribution behavior is expected to be used in thermal and mechanical calculation of fuel assemblies in transients.
The reconstructed power distributions will be used to calculate power densities in all fuel elements in the reactor core with use of BIPR-8 calculation code [1]. Verification calculations have been carried out by comparing the data of element-by-element power distribution in one cassette calculated with use of PERMAK [2] and BIPR-8 codes to test the method used and a new nodule of BIPR-8 where the method is implemented.