Prompt digestion and HPIC separation of rare earth elements in surrogate post-detonation debris material with detection by ICP-MS and gamma spectroscopy.

Prompt analysis of fission products and rare earth elements (REE)s in post-detonation nuclear debris is critical for nuclear forensic analysis. In this work the compatibility of ammonium biflouoride fusion and microwave digestion in combination with high pressure ion chromatography (HPIC) separation was examined for the analysis of REEs. The refractory geological materials USGS G-2, QLO-1a, AGV-2 and BHVO-2 were used as surrogate post-detonation debris. The HPIC separation used a mixed bed ion exchange column with a gradient elution consisting of oxalic acid and diglycolic acid mobile phases. Quantitative recovery for seven REEs was achieved using the in-line HPIC-ICP-MS. An off-line HPIC method was also developed to separate U, Pu, and REE fission products. Collected fractions were analyzed by ICP-MS or gamma ray spectroscopy. The offline HPIC separation with detection of short-lived fission products with gamma ray spectroscopy had detection limits 5-20,000 times lower than quadrupole ICP-MS for stable REEs.