Radial resonance captures in {sup 238}U metal rods and spatial resonance production of {sup 239}Pu in uranium-oxide fuels

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Nuclear Technology

OSTI ID:131653

Bogart, D ^[1]

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1. National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

Precise calculation of radial distribution of resonance region capture in {sup 238}U metal rods and for partially enriched uranium-oxide fuels is important for current and proposed water-moderated power reactors. Advanced core designs for pressurized and boiling water reactors have considered resonance region in-core generation of {sup 239}Pu as a means of extending core operating cycles between refuelings. The calculations of detailed spatial resonance captures are beyond the scope of multigroup codes used for practical reactor core design because of the broad resonance energy groups required. Group average resonance capture cross-section parameters employed may conserve total neutron captures, but the spatial detail is washed out. A simplified method is presented that enables direct calculation of resonance region spatial captures in fuel moderator lattices. The validity of the method is confirmed by comparison with published experimental measurements for epicadmium capture with radial distance from the moderator-fuel interface for metal uranium rods from 0.8 to 5.0 cm in diameter. A method is illustrated for spatial resonance capture in partially enriched uranium-oxide fuel rods, and the spatial complexity of {sup 239}Pu production during conversion of {sup 238}U in the resonance region is discussed. Although the products of the conversion chain can be precisely defined geometrically with operating time, their spatial concentrations cannot be calculated with the accuracy required to determine net production of {sup 239}Pu.

• OSTI ID: 131653
• Journal Information: Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 1 Vol. 112; ISSN 0029-5450; ISSN NUTYBB
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
BWR TYPE REACTORS
CALCULATION METHODS
CAPTURE
DESIGN
FUEL ELEMENTS
ISOTOPE PRODUCTION
NEUTRON REACTIONS
NUCLEAR REACTION YIELD
PLUTONIUM 239
PWR TYPE REACTORS
REACTIVITY
REACTOR CORES
REACTOR KINETICS
TRANSMUTATION
URANIUM 238