Comparison of gadolinium and ZrB/sub 2/ as integral fuel burnable absorbers in PWRs

Conference · Wed Dec 31 23:00:00 EST 1986 · Trans. Am. Nucl. Soc.; (United States)

OSTI ID:6883558

Srinilta, S; Schmidt, R F; Pritchett, J E

This study compares the use of gadolinium and zirconium diboride (ZrB/sub 2/) as integral fuel burnable absorbers (IFBAs) for controlling peaking factors and maintaining an acceptable moderator temperature coefficient (MTC) in pressurized water reactors (PWRs). The ceramic Gd/sub 2/O/sub 3/ is mixed directly with UO/sub 2/, while ZrB/sub 2/ is coated on the surface of the UO/sub 2/ pellet. Because of the lower thermal conductivity and lower melting temperature in the mixture of Gd/sub 2/O/sub 3/ + UO/sub 2/ a reduced uranium enrichment in the gadolinium bearing rods is required. In the ZrB/sub 2/ application, the depletion produces additional helium gas; therefore, the initial back-filled gas pressure has to be reduced. The use of either absorber results in a more complete burnout relative to lumped burnable absorbers, thereby yielding improved uranium utilization. ZrB/sub 2/ is favored over gadolinium as the integral fuel burnable absorber for PWRs because of improved power peaking control, reduced residual activity, and its unchanged uranium enrichment requirement. These factors lead to longer cycle lengths and greater fuel management flexibility in PWRs. The use of ZrB/sub 2/ IFBAs provides a more economical and flexible burnable absorber than gadolinium for PWR applications.

• OSTI ID: 6883558
• Report Number(s): CONF-8711195-
• Journal Information: Trans. Am. Nucl. Soc.; (United States), Journal Name: Trans. Am. Nucl. Soc.; (United States) Vol. 55; ISSN TANSA
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
BROMIDES
BROMINE COMPOUNDS
BURNABLE POISONS
COMPARATIVE EVALUATIONS
ELEMENTS
FUEL MANAGEMENT
GADOLINIUM
HALIDES
HALOGEN COMPOUNDS
MATERIALS
METALS
NEUTRON ABSORBERS
NUCLEAR POISONS
OPTIMIZATION
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POWER DISTRIBUTION
PWR TYPE REACTORS
RARE EARTHS
REACTOR MATERIALS
REACTORS
TRANSITION ELEMENT COMPOUNDS
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZIRCONIUM BROMIDES
ZIRCONIUM COMPOUNDS