Systematic assembly homogenization and local flux reconstruction for nodal method calculations of fast reactor power distributions

Technical Report · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5419693

Dorning, J J

A simultaneous pin lattice cell and fuel bundle homogenization theory has been developed for use with nodal diffusion calculations of practical reactors. The theoretical development of the homogenization theory, which is based on multiple-scales asymptotic expansion methods carried out through fourth order in a small parameter, starts from the transport equation and systematically yields: a cell-homogenized bundled diffusion equation with self-consistent expressions for the cell-homogenized cross sections and diffusion tensor elements; and a bundle-homogenized global reactor diffusion equation with self-consistent expressions for the bundle-homogenized cross sections and diffusion tensor elements. The continuity of the angular flux at cell and bundle interfaces also systematically yields jump conditions for the scaler flux or so-called flux discontinuity factors on the cell and bundle interfaces in terms of the two adjacent cell or bundle eigenfunctions. The expressions required for the reconstruction of the angular flux or the de-homogenization' theory were obtained as an integral part of the development; hence the leading order transport theory angular flux is easily reconstructed throughout the reactor including the regions in the interior of the fuel bundles or computational nodes and in the interiors of the pin lattice cells. The theoretical development shows that the exact transport theory angular flux is obtained to first order from the whole-reactor nodal diffusion calculations, done using the homogenized nuclear data and discontinuity factors, is a product of three computed quantities: a cell shape function''; a bundle shape function''; and a global shape function''. 10 refs.

• Research Organization: Virginia Univ., Charlottesville, VA (United States). Dept. of Nuclear Engineering and Engineering Physics
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG07-90ER12931
• OSTI ID: 5419693
• Report Number(s): UVA-527406/NEEP91/101; ON: DE91017356
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
LMFBR TYPE REACTORS
POWER DISTRIBUTION
ANALYTICAL SOLUTION
CROSS SECTIONS
DIFFUSION
HOMOGENIZATION METHODS
NEUTRON FLUX
NEUTRON TRANSPORT
NEUTRON TRANSPORT THEORY
NODAL EXPANSION METHOD
PROGRESS REPORT
REACTOR LATTICES
REACTOR PHYSICS
THREE-DIMENSIONAL CALCULATIONS
BREEDER REACTORS
DOCUMENT TYPES
EPITHERMAL REACTORS
FAST REACTORS
FBR TYPE REACTORS
LIQUID METAL COOLED REACTORS
NEUTRAL-PARTICLE TRANSPORT
PHYSICS
RADIATION FLUX
RADIATION TRANSPORT
REACTORS
TRANSPORT THEORY
210500* - Power Reactors
Breeding
220100 - Nuclear Reactor Technology- Theory & Calculation