Interdiffusion Behavior of U{sub 3}Si{sub 2} and FeCrAl via Diffusion Couple Studies

Journal Article · Sat Jul 01 00:00:00 EDT 2017 · Transactions of the American Nuclear Society

OSTI ID:23047438

Hoggan, Rita; Harp, Jason; He, Lingfeng ^[1]

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1. Idaho National Laboratory: 2525 Fremont Ave, Idaho Falls, ID 83402 (United States)

Uranium Silicide (U{sub 3}Si{sub 2}) is in use as a dispersion plate fuel in test reactors, but has not been fully tested in light water reactor (LWR) conditions. U{sub 3}Si{sub 2} pellets have been fabricated for use in commercial LWRs as part of an accident tolerant fuel system U{sub 3}Si{sub 2} has a higher uranium loading density as well as a higher thermal conductivity relative to UO{sub 2}. FeCrAl alloy is a candidate cladding material to replace the industry standard, Zircaloy. FeCrAl has outstanding high-temperature mechanical strength and oxidation resistance under accident conditions. The U{sub 3}Si{sub 2}-FeCrAl system is expected to provide more than double the amount of time from a Scram until failure criteria for the reactor is met, as well as producing roughly half the amount of H{sub 2} in the event of a loss of coolant accident (LOCA). Uranium and iron have well know eutectics that may affect/enhance diffusion of the U{sub 3}Si{sub 2}/FeCrAl fuel system. The interaction of iron with molten uranium has been investigated In the U-Fe system, UFe{sub 2}, which melts congruently at 1235 deg. C, forms a eutectic with iron that melts at 1080 deg. C and has a composition of U-77at% Fe. UFe{sub 2} also forms a eutectic with uranium that melts at 725 deg. C and has a composition of U-34at% Fe. The U-34at% Fe eutectic extended the temperature range down to 740 deg. C. Regular operating temperatures for U{sub 3}Si{sub 2} fuel is expected to be around 300 - 400 deg. C. The eutectics of iron and uranium would nominally only be of concern in accident scenarios.

• OSTI ID: 23047438
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 116; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
ACCIDENT-TOLERANT NUCLEAR FUELS
CLADDING
EUTECTICS
FUEL PLATES
FUEL SYSTEMS
IRON
LOADING
LOSS OF COOLANT
OXIDATION
SCRAM
TEST REACTORS
THERMAL CONDUCTIVITY
URANIUM
URANIUM DIOXIDE
URANIUM SILICIDES
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZIRCALOY