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Ohno, Shuji; P. Loewen, Eric*; Auman, L. E.*
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13), 0 Pages, 2005/05
The alkaline extraction method and electro-deposition method have been investigated at the Idaho National Engineering and Environmental Laboratory to remove polonium from a lead-bismuth cooled reactor. Tellurium was used as a surrogate for polonium for these experiments to quantify the migration. From the chemical kinetic measurements of extraction tests using NaOH as alkaline, first and second order alkaline extraction rate constants were suggested to be: k1=300exp(-64300/RT), k2=42700exp(-122400/RT), where R=8.31J/mol/K and T is in degrees K. Some experimental data showed tellurium moving from NaOH back into LBE, allowing the measurement of the reverse rate reaction constant. We suggest the following linear fit to determine the equilibrium constant as a function of the temperature: Log(K)=-3195/T+5.199. The electro-deposition experiments were initiated. The limited number of runs provided the information of the effect of electrodes surface area and temperature on the tellurium collection characteristics. However, further experiments are necessary for acquiring more knowledge. This paper is a continuation of the results reported in the previous ICONE papers: ICONE11-36614 and ICONE12-49396.
Loewen, E. P.*; Auman, L. E.*
JNC TJ9400 2004-003, 159 Pages, 2004/03
JNC-TJ9400-2004-003.pdf:11.69MB
Polonium is the radioactive product of neutron activation of molten lead-bismuth, a promising candidate coolant for advanced fast nuclear reactors. The radiological hazard associated with polonium can be significantly reduced by continuous online removal of polonium from the coolant. The Japanese Nuclear Cycle Development Institute sponsored a three-year research effort to investigate two polonium separation mechanisms (alkaline extraction and electro deposition). Since there are no stable isotopes of polonium, tellurium was used as a surrogate while exploring separation mechanisms. This year, two experimental investigations occurred simultaneously: 1) alkaline extraction chemical kinetic measurements, and 2) design, construct, and perform electrode experiments. The modeling of the Te extraction experiment is completed with the measurement of rate constants, activation energy, and heat of reaction. The electro-deposition experiments were initiated and completed this year, with inconclusive results. Very little consistency was found and more research is needed to improve the amount of sample collected for analysis.