Modelling of CANDU reactivity control devices with the lattice code DRAGON
1994; Elsevier BV; Volume: 21; Issue: 2 Linguagem: Inglês
10.1016/0306-4549(94)90067-1
ISSN1873-2100
AutoresRobert J. Le Roy, G. Marleau, Jaouad Tajmouati, D. Rozon,
Tópico(s)Nuclear Physics and Applications
ResumoThe lattice code DRAGON has been used for modelling the normal operating conditions in CANDU reactors. The integral transport equation is first solved using the collision probability (CP) formalism for 2-D cluster geometries representing standard CANDU cells. Whereas the usual tracking procedure only permits isotropic reflection at the cell boundary, we investigate the effects on a completely reflected cluster cell of the cyclic-tracking procedure that can also treat specular reflection. For CANDU reactivity devices located perpendicularly to the fuel channels, the standard CP formalism is applied to 3-D supercell geometries containing zones of mixed cylindrical and rectangular geometries. A symmetric two-bundle model allows most of the surfaces to be located in the moderator regions, thus reducing discrepancies introduced by the assumption of isotropic boundary currents. Using a single basic definition for the tracking files, efficient algorithms for computation and normalization of CP pertinent to these cell and supercell models are also described. Numerical results include reactivity worths for adjuster rods and zonal control units (ZCU) of a typical CANDU reactor.
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