Electrochemical studies of corrosion of SIMFUEL: Simulated used UO{sub 2} fuel

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:62187

Sunder, S; Shoesmith, D W; Miller, N H ^[1]

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1. Whiteshell Labs., Pinawa, Manitoba (Canada)

The corrosion of SIMFUEL, simulated high-burnup CANDU (CANadian Deuterium Uranium) fuel, was investigated in 0.1 mol{center_dot}dm{sup -3} NaClO{sub 4} solution (pH {approximately} 9.5) as a function of dissolved oxygen concentration using electrochemical techniques and X-ray photoelectron spectroscopy (XPS). Electrodes were constructed of SIMFUEL pellets with compositions close to those of a natural UO{sub 2} fuel that has undergone burnup of 3 at% and 6 at%. The XPS analysis of freshly polished SIMFUEL pellets showed that the extent of uranium oxidation in SIMFUEL was equivalent to that in stoichiometric UO{sub 2}. The SIMFUEL electrodes showed higher conductivity and electrochemical reactivity than the pure UO{sub 2} electrodes. A comparison of the open circuit corrosion potentials of the SIMFUEL electrodes with that of a pure UO{sub 2} electrode in oxygenated solutions showed a much faster increase in the potential for the SIMFUEL electrodes at short times. This suggests that the initial stages of UO{sub 2} oxidation, i.e., UO{sub 2} {yields} UO{sub 2+x} {yields} UO{sub 2.33}, are facilitated by fission product impurities in the UO{sub 2} matrix. However, the {open_quotes}steady-state{close_quotes} oxidation of uranium in SIMFUEL by the dissolved O{sub 2} was similar to that observed in pure UO{sub 2} under similar conditions.

• OSTI ID: 62187
• Report Number(s): CONF-921101--Vol.294
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
40 CHEMISTRY
ACTINIDES
ELECTROCHEMICAL CORROSION
ELECTROCHEMISTRY
ELECTRODES
FISSION
IMPURITIES
OXIDATION
SPENT FUELS
UNDERGROUND DISPOSAL
URANIUM DIOXIDE
X-RAY SPECTROSCOPY