PENENTUAN RECOVERY NEODYMIUM DAN CERIUM PADA PROSES PEMISAHAN ISOTOP DARI SIMULASI PEB U3Si2/Al PRA IRADIASI

Abstract

DETERMINATION OF NEODYMIUM AND CERIUM RECOVERY IN ISOTOPE SEPARATION PROCESS OF SIMULATED PRE-IRADIATED U3Si2/Al FUEL. Neodymium (Nd) is one of the fission product isotopes used as an indicator of nuclear fuel  burn-up because Nd isotope is a stable fission product, has a sufficiently great yield, is not volatile and has low neutron-capture cross- section. Burn-up determination using Nd can support and verify the results of the burn-up determined by  using Cs, U and Pu isotopes. Destructive burn-up determination (Destructive Test, DT) is based on the determination of  specific isotopes that is performed physicochemically using mass spectrometer equipment. Based on ASTM E 321-69  method for Nd isotope analysis, Nd separation from Ce is required because 142Ce isotope interferes with 142Nd  measurement due to their being isobars, and this phenomenon will affect the results of the burn-up calculations. In  addition, Nd isotope in U3Si2/Al fuel is present along with other fission isotopes such as 235U, 239Pu, 148Nd, 137Cs,  152Eu, 90Sr, 143Ce, 103Ru, 95Zr, and 95Nb. Therefore, to obtain an accurate value to be used as burn-up indicator, the  isotopes must be separated. Before the Nd and Ce separation, several separation phases of Cs isotopes (137Cs, 134Cs), U isotopes (234U, 235U, 236U, 238U), Pu isotopes (239Pu, 238Pu) and other isotopes (152Eu, 90Sr, 103Ru, 95Zr and 95Nb) were done. The determination of separation recovery aimed to determine the amount of Nd and Ce at each stage of the  separation process of other isotopes prior to the separation stage of Nd and Ce. The determination of recovery was  conducted by a simulation of fresh U3Si2/Al solution plus standard solutions of Cs, U, Nd and Ce. The recovery for Nd  and Ce from Cs separation phase using zeolites were 69.91% and 64.42% respectively while the recovery of Nd and Ce at  Pu and U separation phase were close to 100%. The recovery values of Nd and Ce were then used as a correction in the  calculation of Nd and Ce separation from the fuel solution, and the corrected values can then be used as a reference in determining the burn-up of U3Si2/Al fuel using Nd as an indicator.