Fast burn-up measurement in simulated nuclear fuel using ICP-MS

Abstract

Abstract A double focusing ICP-MS with pulsed laser deposition (PLD) of thin films as sampling tool has been used in simulated spent fuels for a quick measurement on burn-up of nuclear reactor fuels by measuring the atom ratio of U (representing total heavy elements of mass >225) to selected lanthanide fission monitors. A linear correlation is established between the measured intensity ratios of 238U/143Nd, 238U/(145Nd+146Nd) and 238U/139La against the actual atom ratios present in the samples. The samples in the form of solution are obtained by dissolving different concentrations of U, Nd and La in nitric acid medium, representing a wide burn-up range (0.19 to 19.98 at.%). In addition, PLD films were deposited using 1064 nm, 100 ps Nd:YAG laser pulses on solid targets of U and Nd mixed oxide, corresponding to different burn-ups. ICP-MS analysis of these films after dissolving in nitric acid showed values close to that of the solid target composition. Burn-up data obtained with films deposited at a high laser power density of 1.67×1011 W/cm2 agrees well with the values of the respective target compositions compared to the films deposited at 3.3×109 W/cm2. Present analytical method requires only a very small sample quantity, typically a few nanograms and generally does not require any chemical separation in comparison to the conventional mass spectrometry method, which is traditionally employed to determine the burn-up of a nuclear fuel.