Cobalt-60, Barium-133, Cesium-137, and Europium-152 migration from cementitious sources through sediment under field conditions.

Safe and effective storage of radioactive waste is essential to protect human and environmental health. Due to the potential for accidental releases and the severity of the associated risks, it is imperative to further understand radionuclide transport should an accident occur. This study was the second set of measurements conducted in 2022 of an ongoing experiment that has analyzed the vadose zone migration of radionuclides from cementitious wasteforms at the Savannah River Site over the last ten years.

Hybrid extractive scintillator resin for simultaneous concentration and detection of plutonium from aqueous solutions.

A scoping study of a commercially available resin selective for aqueous plutonium (Pu), AnaLig® Pu-02, modified with scintillator was investigated as a scheme to simultaneously concentrate and detect Pu in aquatic matrices. The extractive scintillating resin was comprised of a silica base, functionalized for plutonium extraction, grafted with plastic scintillator of polyvinyl toluene (PVT) and 2-(1-naphthyl)-4-vinyl-5- phenyloxazole (vNPO) fluor. Scintillator was incorporated onto the AnaLig® Pu-02 resin in a two-step process of silanization followed by surface-polymerization.

Polyamidoxime-based membranes for the rapid screening of uranium isotopes in water.

Traditional radiochemistry approaches for the detection of trace-level alpha-emitting radioisotopes in water require lengthy offsite sample preparations and do not lend themselves to rapid quantification. Therefore, a novel platform is needed that combines onsite purification, concentration, and isotopic screening with a fieldable detection system. This contribution describes the synthesis and characterization of polyamidoxime membranes for isolation and concentration of uranium from aqueous matrices, including high-salinity seawater.

Membranes for the Capture and Screening of Waterborne Plutonium Based on a Novel Pu-Extractive Copolymer Additive.

This contribution describes the fabrication of plutonium-adsorptive membranes by non-solvent induced phase separation. The dope solution comprised poly(vinylidene fluoride) (PVDF) and a Pu-extractive copolymer additive of PVDF--poly(ethylene glycol methacrylate phosphate) (EGMP) in dimethylformamide (DMF). The effects of casting conditions on membrane permeability were determined for PVDF membranes prepared with 10 wt% PVDF--EGMP.

Hybrid extractive scintillator resin for simultaneous concentration and detection of radiocesium from aqueous solutions.

A hybrid extractive scintillating resin (HESR) was developed for the concentration and detection of radiocesium. The HESR comprised a cesium-selective potassium ferrierite ion-exchange powder embedded in porous polymeric scintillating beads. It was prepared by carrying out suspension polymerization of 4-methylstyrene with divinylbenzene, 2-(1-naphthyl)-4-vinyl-5-phenyloxazole fluor and ferrierite-K powder.

Integration of ecosystem science into radioecology: A consensus perspective.

In the Fall of 2016 a workshop was held which brought together over 50 scientists from the ecological and radiological fields to discuss feasibility and challenges of reintegrating ecosystem science into radioecology. There is a growing desire to incorporate attributes of ecosystem science into radiological risk assessment and radioecological research more generally, fueled by recent advances in quantification of emergent ecosystem attributes and the desire to accurately reflect impacts of radiological stressors upon ecosystem function. This paper is a synthesis of the discussions and consensus of the workshop participant's responses to three primary questions, which were: 1) How can ecosystem science support radiological risk assessment? 2) What ecosystem level endpoints potentially could be used for radiological risk assessment? and 3) What inference strategies and associated methods would be most appropriate to assess the effects of radionuclides on ecosystem structure and function? The consensus of the participants was that ecosystem science can and should support radiological risk assessment through the incorporation of quantitative metrics that reflect ecosystem functions which are sensitive to radiological contaminants.

Functionalized Polymer Thin Films for Plutonium Capture and Isotopic Screening from Aqueous Sources.

The rapid screening of plutonium from aqueous sources remains a critical challenge for nuclear nonproliferation efforts. The determination of trace-level Pu isotopes in water requires offsite sample preparation and analysis; therefore, new methods that combine plutonium purification, concentration, and isotopic screening in a fieldable detection system will provide an invaluable tool for nuclear safeguards. This contribution describes the development and characterization of thin polymer-ligand films for the isolation and concentration of waterborne Pu for direct spectroscopic analyses.

A Mixed-methods Approach for Improving Radiation Safety Culture in Open-source University Laboratories.

The radiation safety culture of those working in university open-source radioactive material laboratories was assessed by conducting both surveys and behavioral observations. Baseline results (n = 82, 89% response rate) of assessed safety culture categories indicated safety practices and safety compliance were the most in need of improvement. Specific training based on these results was provided to laboratory members at Princeton University, with creative signage and a safety newsletter posted in and around laboratories for reinforcement, in a targeted effort to improve the radiation safety culture.

High effectiveness of pure polydopamine in extraction of uranium and plutonium from groundwater and seawater.

Sorption properties of polydopamine (PDA) for uranium and plutonium from an aqueous environment are reported at three different pH values (2, 4 and 6.5-7). In addition to deionized (DI) water, artificial groundwater (GW) and seawater (SW) were used with U uptake close to 100% in each case.

Thermal Neutron Characterization and Dose Modeling of a 239PuBe Alpha-Neutron Source.

Determination of neutron dose can be challenging and requires knowledge of neutron flux as a function of energy. The goal of this project was to characterize the thermal neutron flux of a 37 GBq PuBe alpha-neutron source and model the associated neutron dose using version MCNPX of the Monte-Carlo N-Particle transport codes. The PuBe source was placed in a neutron howitzer, and foil activation (dysprosium foils with and without cadmium covers) was used at various distances to determine thermal neutron flux, which was then used to verify the MCNPX model representing the system.

Application of new covalently-bound diglycolamide sorbent in sequential injection analysis flow system for sample pretreatment in ICP-MS determination of Pu at ppt level.

Diglycolamide ligands are widely applied in the analysis of radionuclides, especially lanthanides and actinides. They are used in liquid-liquid extraction procedures or in solid-phase extraction sorbents where they are adsorbed on the surface of hydrophobic polymers. The main objective of this study was to synthesize the N,N,N'N'-tetrahexyl diglycolamide with one vinyl terminating group (vTHDGA) for further covalent immobilization on the polystyrene-divinylbenzene polymeric support.

Evaluation of Shiryaev-Roberts procedure for on-line environmental radiation monitoring.

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.

One-dimensional Spatial Distributions of Gamma-ray Emitting Contaminants in Field Lysimeters Using a Collimated Gamma-ray Spectroscopy System.

One-dimensional scans of gamma-ray emitting contaminants were conducted on lysimeters from the RadFLEX facility at the Savannah River Nationals Laboratory (SRNL). The lysimeters each contained a contamination source that was buried in SRNL soil. A source consisted of Cs, Co, Ba, and Eu incorporated either into a solid waste form (Portland cement and reducing grout) or applied to a filter paper for direct soil exposure.

Rapid Sample Preparation for Alpha Spectroscopy with Ultrafiltration Membranes.

This contribution describes a rapid, fieldable alpha spectroscopy sample preparation technique that minimizes consumables and decreases the nuclear forensics timeline. Functional ultrafiltration membranes are presented that selectively concentrate uranium directly from pH 6 groundwater and serve as the alpha spectroscopy substrate. Membranes were prepared by ultraviolet grafting of uranium-selective polymer chains from the membrane surface.

High-Resolution 4D Preclinical Single-Photon Emission Computed Tomography/X-ray Computed Tomography Imaging of Technetium Transport within a Heterogeneous Porous Media.

A dynamic Tc tracer experiment was performed to investigate the capabilities of combined preclinical single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) for investigating transport in a heterogeneous porous medium. The experiment was conducted by continuously injecting a Tc solution into a column packed with eight layers (i.e.

Extractive scintillating polymer sensors for trace-level detection of uranium in contaminated ground water.

This contribution describes the synthesis of robust extractive scintillating resin and its use in a flow-cell detector for the direct detection of uranium in environmental waters. The base poly[(4-methyl styrene)-co-(4-vinylbenzyl chloride)-co-(divinylbenzene)-co-(2-(1-napthyl)-4-vinyl-5-phenyloxazole)] resin contains covalently bound fluorophores. Uranium-binding functionality was added to the resin by an Arbuzov reaction followed by hydrolysis via strong acid or trimethylsilyl bromide (TMSBr)-mediated methanolysis.

New Efficient Organic Scintillators Derived from Pyrazoline.

We report on the synthesis, spectroscopic and scintillation properties of three new pyrazoline core based fluorophores. Fluorescence properties of the fluorophores have been studied both in a solution state and in a solid polyvinyltoluene (PVT) resin matrix of different porosity. The synthesized fluorophores were found to be promising candidates for application in plastic scintillators for detection of ionizing radiation (alpha, beta particles, γ rays and neutrons) and demonstrated superior efficiency in comparison to the existing commercially used fluorophores (2-(1-naphthyl)-5-phenyloxazole (αNPO), 9,10-diphenylanthracene, etc.

Development of a novel method for the determination of aqueous inorganic 129I speciation.

The objective of this research was to develop a method suitable for the determination of aqueous concentrations of radioactive iodine as I2, I(-), and IO3(-). As one of the primary risk-drivers and contaminants of concern at nuclear waste repositories, the accurate determination of (129)I in aqueous systems is of significant concern. The redox-active nature of iodine makes its mobility and fate in the environment difficult to predict, thus underscoring the importance of species-specific determination of iodine concentrations.

Bayesian analyses of time-interval data for environmental radiation monitoring.

Time-interval (time difference between two consecutive pulses) analysis based on the principles of Bayesian inference was investigated for online radiation monitoring. Using experimental and simulated data, Bayesian analysis of time-interval data [Bayesian (ti)] was compared with Bayesian and a conventional frequentist analysis of counts in a fixed count time [Bayesian (cnt) and single interval test (SIT), respectively]. The performances of the three methods were compared in terms of average run length (ARL) and detection probability for several simulated detection scenarios.

CUSUM analyses of time-interval data for online radiation monitoring.

Three statistical control chart methods were investigated to determine the one with the highest detection probability and the best average run length (ARL). The three control charts include the Shewhart control chart of count data, cumulative sum (CUSUM) analysis of count data (Poisson CUSUM), and CUSUM analysis of time-interval (time difference between two consecutive radiation pulses) data (time-interval CUSUM). The time-interval CUSUM (CUSUMti) control chart was compared with the Poisson CUSUM (CUSUMcnt) and the Shewhart control charts with experimental and simulated data.

Preparation of polymer-coated, scintillating ion-exchange resins for monitoring of 99Tc in groundwater.

The present study was oriented to prepare new scintillating anion-exchange resins for measurement of (99)TcO(4)(-) in natural waters. The organic fluor 2-(1-naphthyl)-5-phenyloxazole was diffused into (chloromethyl)polystyrene resin. Thereafter, a thin layer of poly[[2-(methacryloyloxy)ethyl]trimethylammonium chloride] was grafted from the resin surface by surface-initiated atom transfer radical polymerization as an attempt to overcome potential problems related to the leaching of fluor molecules during usage.

Online detection of radioactive iodine in aqueous systems through the use of scintillating anion exchange resin.

The objective of this research was to develop a scintillating anion exchange resin selective for monitoring (129)I at concentrations at or below ~0.4 Bq/L. One of the primary long-term risk-drivers and contaminants associated with nuclear waste sites is (129)I.

Mobility of radionuclides in soil/groundwater system: comparing the influence of EDTA and four of its degradation products.

The adsorption behavior of 241Am, 60Co, 137Cs and 85Sr in the presence and absence of chelating ligands (ethylenediaminetetraacetic acid, ethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, iminodiaceiticacid and methyliminodiacetic acid) was investigated. Sorption affinity in the absence of chelating ligands followed: Am(III)>Co(II)>Cs(I)>Sr(II). The presence of chelating ligands generally had little effect on sorption of 85Sr and 137Cs with Kd values 110 and 690 mL g(-1), respectively.