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Abstract Water can become contaminated as a result of a leak from a nuclear facility, such as a waste facility, or from clandestine nuclear activity. Low-level on-line radiation monitoring is needed to detect these events in real time. A Bayesian control chart method, Shiryaev-Roberts (SR) procedure, was compared with classical methods, 3- σ and cumulative sum (CUSUM), for quantifying an accumulating signal from an extractive scintillating resin flow-cell detection system. Solutions containing 0.10–5.0 Bq/L of 99Tc, as T 99 cO 4 − were pumped through a flow cell packed with extractive scintillating resin used in conjunction with a Beta-RAM Model 5 HPLC detector. While T 99 cO 4 − accumulated on the resin, time series data were collected. Control chart methods were applied to the data using statistical algorithms developed in MATLAB. SR charts were constructed using Poisson (Poisson SR) and Gaussian (Gaussian SR) probability distributions of count data to estimate the likelihood ratio. Poisson and Gaussian SR charts required less volume of radioactive solution at a fixed concentration to exceed the control limit in most cases than 3- σ and CUSUM control charts, particularly solutions with lower activity. SR is thus the ideal control chart for low-level on-line radiation monitoring. Once the control limit was exceeded, activity concentrations were estimated from the SR control chart using the control chart slope on a semi-logarithmic plot. A linear regression fit was applied to averaged slope data for five activity concentration groupings for Poisson and Gaussian SR control charts. A correlation coefficient (R 2) of 0.77 for Poisson SR and 0.90 for Gaussian SR suggest this method will adequately estimate activity concentration for an unknown solution. Highlights • Shiryaev-Roberts (SR) procedure uses less volume than classical control charts. • Poisson SR uses least volume but could be confused as a false positive. • Gaussian SR has low false positive rate and continuous increasing trend. • Activity concentration can be estimated from SR control chart slope. [ABSTRACT FROM AUTHOR]

Abstract: Combining extraction and scintillation properties within the same material is a relatively new approach in development of sensors for detection of radioactive elements. Structural organization of such materials at a nanoscale typically offers higher efficiency of detection and shorter response time. In this contribution, several new protocols are discussed for fabrication of stable extractive scintillating systems based on commercial Superlig 620 (SL) material with high affinity to radiostrontium. Application of hybrid organic–inorganic beads with SL particles used as core and halloysite clay nanotubes (HNT) modified with a polyvinyltoluene (PVT) brush as a permeable shell combines high‐performance extracting properties of the SL material with efficient light emission properties of the polymer scintillator. The developed SL–HNT–PVT hybrid extractive scintillating material allows real‐time detection of low‐level concentrations of radiostrontium in water. Moreover, the suggested approach is not limited to detection of Sr but can find broader application in development of chemical, biological, or radioluminescent sensors and multifunctional materials. [ABSTRACT FROM AUTHOR]