Determination of 36Cl in nuclear waste from reactor decommissioning

An analytical method for the determination of Cl-36 in nuclear waste such as graphite, heavy concrete, steel, aluminum, and lead was developed. Several methods were investigated for decomposing the samples. AgCl precipitation was used to separate Cl-36 from the matrix elements, followed by ion-exchange chromatography to remove interfering radionuclides. The purified Cl-36 was then measured by liquid scintillation counting. The chemical yield of chlorine, as measured by ICPMS, is above 70% and the decontamination factors for all interfering radionuclides are greater than 10(6). The detection limit of this analytical method for Cl-36 is 14 mBq. The method has been used to determine Cl-36 in heavy concrete, aluminum, and graphite from the Danish DR-2 research reactor.