Automated Analysis of Radionuclides in Nuclear Waste:  Rapid Determination of ⁹⁰Sr by Sequential Injection Analysis

Abstract

A rapid, automated, microanalytical procedure for the determination of 90 Sr in aged nuclear waste has been developed. It is based on a sequential injection analysis (SIA) system which rapidly separates 90 Sr from 90 Y, 137 Cs, and other radionuclides. The isolated 90 Sr is then detected on-line with a flow-through liquid scintillation counter. The separation is achieved using a sorbent extraction minicolumn containing a resin (EIChrom, Sr-Spec) that selectively binds 90 Sr as a crown ether complex under acidic conditions. The 90 Sr is eluted with water, mixed with liquid scintillation cocktail, and detected in the flow cell of the counter. Sample 90 Sr activity can be quantified from peak areas, giving linear calibration curves. The instrument can also be operated in a stoppedflow mode for longer counting times. Analyses of aged nuclear waste samples from the Hanford site by the SIA method and a manual method were in excellent agreement: correlation coefficient R ) 0.994. Sample analysis by the SIA method is complete in less than 40 min. The advantages of the new 90 Sr analyzer include faster analysis, greater precision, reduced labor costs, and reduced secondary waste. Worker safety is improved because solution handling operations are fully automated and contained.

Systematic evaluation of a strontium-specific extraction chromatographic resin for obtaining a purified Sr fraction with quantitative recovery from complex and Ca-rich matrices

“…Besides these manual separation techniques, also automated chromatographic procedures have been developed [24][25][26][27] and even coupled on-line to (MC-)ICP-MS for subsequent Sr isotope ratio analysis, 13,28,29 although quantitative Sr recoveries were not in all cases obtained.…”

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

“…has not been applied for the determination of radionuclides until 1996 [185]. With the requirement of rapid analysis of radionuclides for emergency purpose and the increased application of ICP-MS, the automated analysis of radionuclides by hyphenation of flow injection/sequential injection for on-line separation with ICP-MS measurement has becoming more attractive for waste and environmental radioactivity analysis.…”

“…Grate et al [185,292] described a automated method for the determinations of 90 Sr in nuclear waste by using a sequential inject separation and a flow through liquid scintillation counter for on-line detection. In this method, an Eichrom Sr-Spec resin was used for the extraction chromatographic separation, which can efficiently separate the interfering radionuclides, such as 137 Cs and 90 Y from 90 Sr.…”

“…In recent years, a big effort was given to develop a rapid analytical method for the determination of 90 Sr, which is stimulated by the requirement for the emergency action of the accident and terrorist attack. By solvent extraction, extraction chromatography separation, flow injection technique for the separation of 90 Sr from the matrix, and direct measurement of 90 Sr by LSC, 90 Sr can be determined in a short time (< 1 day) [184,185].…”

Application of Moveable Suspensions of Solid Particles in Flow Analysis

“…With ICP-MS a direct injection high efficiency nebulizer was adopted from earlier work in the literature [59], and SIA measurements were made with a LOV rotary valve. In the case of the radiometric measurements a flow-through liquid scintillation detector was adopted with a 0.5 mL flow cell described in earlier FIA measurements [60].…”