Sequential Injection Separation System with Stopped-Flow Radiometric Detection for Automated Analysis of⁹⁹Tc in Nuclear Waste

Abstract

An automated procedure for the determination of (99)Tc in aged nuclear waste has been developed. Using advanced sequential injection (SI) analysis instrumentation, (99)Tc(VII) is separated from radioactive and stable interferences using a TEVA resin column that selectively retains pertechnetate ion from dilute nitric acid solutions. The separated (99)Tc is eluted with 6 M nitric acid and quantified on-line with a flow-through liquid scintillation detector. A stopped-flow technique has been optimized that improves the analysis precision and detection limit compared to continuous-flow detection, reduces consumption of liquid scintillation cocktail, and increases sample throughput by separating the next sample while the present sample is being counted. The detection limit is 30 pCi, or 2 ng, of (99)Tc, using a 15-min stopped-flow period. The analysis time is 40 min for the first sample and is reduced to 20 min for each subsequent sample. Processed nuclear waste samples from the Hanford site were successfully analyzed by this new method.

Determination of technetium-99 in environmental samples: A review

“…Although some automated analysis procedures have been reported for determination of radionuclides like Pu in environmental samples [131], the application of these approaches for 99 Tc determination is still limited and only applied in few laboratories [91,132]. In early 57 studies, the automation of the analysis of 99 Tc is mainly focused on the separation step using anion exchange or extraction chromatography techniques.…”

“…Compared with the conventional manual procedure, separation using flow injection system is faster and less labour intensive; however, because a small column is applied for 99 Tc purification, the decontamination of Mo and Ru is poor, especially for large samples, if no other separation method is included, which causes a deteriorated detection limit for 99 Tc. Egorov et al [132] introduced an approach using a FIALab 3000 sequential injection system with stopped flow radiometric detection for automated determination of 99 Tc in nuclear waste. Fig.…”

Radionuclide Sensors for Subsurface Water Monitoring

“…Use of anion exchange materials for pertechnetate separations is well known. [35,[44][45][46][47][48][49][50][51] Figure 3a,b illustrate the sensor response and % breakthrough for a single Tc standard followed by a blank. A steady state signal is observed at full breakthrough, and the response is completely reversible.…”

Interfacial Chemistry and Engineering Annual Report 2000

“…In this approach, a suspension of surface derivatized beads is introduced into a flow system and then automatically trapped by a barrier that stops the beads but allows the fluid to proceed Ruzicka and Scampavia 1999;Ruzicka 1998). This produces a small microcolumn of beads (only about a microliter in volume) in a location for observation.…”