Behavior of Carbon and Uranium at Radioactive Graphite Heating in Water Vapor. Thermodynamic Modeling

et al. 2020

Kms

Behavior of U, Pu radionuclides was investigated when heating radioactive graphite in NaCl – KCl – Na2CO3 – K2CO3 melt with NiO additives using the thermodynamic modeling method. Calculations were made by the TERRA software that is used for the determination of phase composition, thermodynamic and transport properties, taking into account chemical and phase changes in temperature range 373 – 3273 K. Calculation of equilibrium phase composition and parameters of equilibrium was carried out using reference information about properties of the individual substances (INVATERMO, HSC, etc.). This study demonstrates that at a temperature of 1273 K the condensed carbon burns down with the formation of CO and CO2. Increasing temperature to 1673 K causes the condensed compounds of uranium to evaporate. This study determined that uranium exists in the form of ionized UO−3 in temperature range from 1673 to 3273 K. Plutonium exists in the form of gaseous PuO2, PuO in temperature range 2373 – 3273 K. Keywords: thermodynamic modeling, radionuclides, radioactive graphite

Section: Experimental Techniquementioning

confidence: 99%

Thermodynamic Analysis of Radioactive Graphite Oxidation in NiO-NaCl-KCl-Na2CO3-K2CO3 Melt in the Atmosphere of Argon

et al. 2020

Kms

The behavior of radioactive metals (Am, Eu, Sr) during the processing of radioactive graphite in salt melts

et al. 2019

J. Phys.: Conf. Ser.

The behavior of Am, Eu, Sr radionuclides was investigated by thermodynamic modeling method at heating of radioactive graphite in NaCl – KCl – Na2CO3 – K2CO3 molten salt with additives of nickel oxide NiO. The integrated thermodynamic analysis was carried out by means of TERRA software in temperature range 373-3273 K to determine possible composition of condensed and gaseous phases. It was established that americium is in gaseous state in temperature range 2773-3273 K. Europium is in the forms of gaseous EuO and Eu in temperature range 2373-3273 K. Strontium is in the forms of gaseous SrCl2, SrCl, Sr, SrO in temperature range 2373-3273 K.

Thermodynamic modeling of the gas-plasma phase in the processing of radioactive graphite in a gas plasma furnace

2020

J. Phys.: Conf. Ser.

The method of thermodynamic modeling was used to determine composition and thermophysical properties of a gas-plasma phase of a system of radioactive graphite – water vapor in the temperature range from 1000 to 3200 K. It has been established that in the temperature range from 1000 to 1100 K, the main components of the gas-plasma phase are H2, CO, H2O, CO2, CH4. In the temperature range from 1100 to 2200 K – H2, CO, H2O, CO2. At temperatures from 2200 to 2600 K those are H2, CO, H2O, CO2, H. In the temperature range from 2600 to 3000 K those are H2, CO, H2O, CO2, H, OH. In the temperature range from 3000 to 3200 K those are H2, CO, H2O, H, CO2, OH, O, O2. The thermophysical properties of the system under consideration have been calculated: specific volume, entropy, enthalpy, total internal energy, number of moles in the system.