Investigation of explosion hazards of the extraction mixture “tributyl phosphate in n-dodecane – solution of nitric acid” under adiabatic conditions

Investigation of explosion hazards of the extraction mixture “tributyl phosphate in n-dodecane – solution of nitric acid” under adiabatic conditions

Regarding to justification of explosion safety of extraction processes carried out at nuclear fuel cycle facilities, the results of determining the conditions for the occurrence of a thermal explosion in the two-phase extraction system “tributyl phosphate in n-dodecane – solution of nitric acid” in sealed vessels by accelerating rate calorimetry are presented.
It is shown that heating of samples in the adiabatic calorimeter leads to a decrease in the temperature values of the beginning of the transition of the exothermic reaction to the explosion mode compared with heating samples in a thermostat with the set temperature.
It was found that when stepwise heating is used in the adiabatic calorimeter, the temperature of the onset of a thermal explosion decreases from 125 to 100 °C with an increase in the concentration of nitric acid from 3 to 10 mol/l, and the explosion pressure increases from 0.15 to 6.3 MPa, respectively.
A change in the nature of the explosive process has been noted in the range of nitric acid concentrations between 5 and 8 mol/l. The kinetic parameters of the explosive process are calculated based on changes in temperature and pressure.

► Keywords: tributyl phosphate, nitric acid, accelerating rate calorimetry, thermal explosion, nuclear fuel cycle facilities.

Article language: Russian. Pp. 24–37. [in Russian]. DOI: 10.26277/SECNRS.2025.117.3.003.