The CASMO-4 r-z pin cell calculation for lattices containing gray gadolinia rods

Conference · Wed Jan 01 04:00:00 EST 1992 · Transactions of the American Nuclear Society; (United States)

OSTI ID:7058069

Knott, D; Edenius, M ^[1]

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1. Studsvik Co., Newton Centre, MA (United States)

In lattice physics codes, pin cell calculations are performed to produce a flux spectrum that is then used to condense and, if desired, homogenize the cross sections of each pin cell to a smaller group structure in preparation for the two-dimensional transport calculation on the entire lattice. If the pellets within a fuel pin are uniform within an axial region of the assembly represented by the lattice, the pin cell calculation may be performed using a one-dimensional cylindrical geometry. This geometry applies to most pin types, including fuel pins containing burnable absorbers, such as gadolinia. These gadolinia pin types, where the pellets are uniform axially, are called black gadolinia rods. In certain ABB designs, gadolinia pellets and UO{sub 2} pellets are alternately stacked within some portion of a fuel rod. Such rods, called gray gadolinia rods, enhance the depletion rate of the gadolinia. For these designs, the fuel rods are no longer uniform in the axial direction, and a one-dimensional cylindrical pin cell calculation is no longer applicable. To this end, CASMO-4 includes the capability to perform the pin cell calculation using a two-dimensional r-z geometry. The r-z pin cell calculation in CASMO-4 allows one more degree of freedom when considering burnable absorber design for reactivity control. The use of the collision probability flux solution lends consistency to the overall model, and the variable mesh capability allows the user to place detail where it is most needed. The r-z geometry may also find other applications in the future.

• OSTI ID: 7058069
• Report Number(s): CONF-920606--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 65
• Country of Publication: United States
• Language: English

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C CODES
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