Determination Of Tritium Research Articles

NATURAL OR ARTIFICIAL TRITIUM IN RIVERS – THE ASSESSMENT USING SYMMETRICAL INDEX

Tritium, hydrogen isotope, with a half-life of 12.3 years, is produced in two ways: naturally and artificially. Naturally, tritium is generated through the interaction of cosmic radiation protons and neutrons with gases in the upper atmosphere. Artificially, tritium origins from the atmospheric nuclear tests, production from nuclear reactors, future fusion reactors, fuel reprocessing plants, heavy water production facilities and commercial production for medical diagnostics, radiopharmaceuticals, luminous paints. Elevated concentrations of tritium in the environment are of great public concern. Considering the fact that nuclear power plants are located on rivers, knowing the activity concentration of this isotope in rivers is of great importance. This work presents the results for tritium determination in Danube and Sava River in Belgrade, Serbia. The origin of tritium was estimated using a mathematical parameter, symmetrical index.

An LSC approach for tritium determination in gaseous mixtures optimized with respect to handling, reaction parameters and miniaturization towards microfluidic analysis

Abstract The handling and analysis of gaseous tritium is of interest for hydrogen isotope separation experiments. In this work, we present an easy-to-handle setup for catalytic oxidation to HTO, recovering all of the initially dosed gaseous tritium as determined by LSC, using CuO as a catalyst at a reaction temperature of 900 °C. Aiming to reduce cocktail waste, the LSC determination was downscaled to a microfluidic setup. The performance was evaluated based on the counting efficiency, which was shown to decrease significantly, as the sample volume was reduced to µl amounts, while no changes were observed over a wide range of sample-to-cocktail ratios.

Low-level tritium measurements in freshwater and seawater samples

The aim of this study was to test two potential tritium determination methods (with and without electrolysis enrichment) suitable for low-level measurements. Both methodologies were applied to water samples from the Baltic Sea and ten Polish rivers providing new data on tritium activity concentration. Optimization steps carried out to the standard method lowered minimum detectable activity concentration (MDC) from 3.1 to 1.8 Bq L–1 (at 95% confidence level) enabling to apply it to environmental water samples. However, electrolytic enrichment method of MDC of 0.20 Bq L–1 provided more accurate results for tritium activity concentration in surface waters.

DETERMINATION OF TRITIUM IN VEGETATION IN THE OBSERVATION AREA OF REACTOR WWR-K IN KAZAKHSTAN

In assessing the impact of radiation-hazardous facilities on the environment and humans, considerable attention is currently paid to the problem of tritium and its compounds intake. It is important to note that to date there are no effective industrial technologies for efficient capture of this radionuclide. As a result, all the tritium produced during the operation of nuclear power plants with emissions and discharges is released into the environment. This leads to increased tritium concentrations in the environment, including vegetation. The aim of this work is to develop and adapt a set of methods for sample preparation and determination of tritium in vegetation samples. Methodology: A special Carbolite Gero MTT tube furnace was used to improve sample preparation methods and maximise the recovery of organically bound tritium from vegetation. Tritium was measured by liquid scintillation beta spectrometry. Results and Discussion: This research paper presents the results of the study and implementation of the method of tritium determination in vegetation near the VVR-K reactor located in the city of Almaty, Kazakhstan. Conclusions: The developed method of tritium determination in vegetation can be applied for radiation monitoring of tritium content and its compounds in the vicinity of nuclear industrial facilities. The presented data emphasise the need for systematic studies of tritium accumulation in environmental components. It is expected that in the future, using the implemented method, the studied area will be studied in detail, taking into account an extended set of factors: meteorological conditions, reactor operation mode and others. Thus, for a more complete and reliable assessment of tritium radionuclide activity determination, it is necessary to carry out works to determine the type of vegetation accumulating this isotope.

Toward an efficient determination of tissue-free water tritium in food.

Tritium in the environment constitutes a radiological concern because it can become part of the hydrogen pool in environmental and biological reservoirs and thereby expose people to radiation. Tissue-free water tritium (TFWT) analysis in food is an important subject of environmental radiation monitoring which plays an important role in the estimation of health risks from environmental tritium exposure. At present, tritium content in food is generally determined by liquid scintillation counter (LSC). To improve the analytical efficiency in tritium determination, we developed a novel method to treat TFWT in food using microporous membranes. The microporous membrane treatment method developed in this study has the following characteristics: It has a wide range of application and can process TFWT samples with conductivity below 5 μS/cm. Sample loss for the microporous membrane treatment is approximately 5%. The average treatment time is only 5 min, significantly shortened compared with the currently used atmospheric distillation treatment method (1.5 h). The results of the comparison and spike experiment show that the samples prepared by microporous membrane treatment provides equally satisfactory tritium measurement results as classic distillation method. The developed microporous membrane method is simple to operate, efficient, and environmentally friendly, and effectively improves the analysis efficiency of TFWT in food.

Determination of tritium in large volume of seawater using electrolytic enrichment and LSC and its application for the East China Sea water

Determination of tritium in large volume of seawater using electrolytic enrichment and LSC and its application for the East China Sea water

A compact, dual-zone vertical tube furnace for the determination of tritium and carbon-14 in decommissioning wastes

A compact dual zone, two work-tube, vertical tube furnace system (Raddec Pyrolyser-Mini) has been designed for the determination of H-3 and C-14 in decommissioning wastes. An optimised methodology was developed following improvements to sample holder and bubbler trap design, sample loading and loading temperature, as well as length and style of heating programmes. A significant efficiency enhancement was obtained through ‘hot-loading’ of the sample into the furnace at 600 °C before finally ramping to 900 °C. Direct trapping of H-3 and C-14 in a scintillation vial located in a special anti-suck-back bubbler further improved operations, leading to a reduction in analysis time and measurement sensitivity. Co-trapping of the analytes and dual-label liquid scintillation counting also proved effective. Overall, the developed methodology led to a reduced analyte extraction/trapping time of 150 min whilst achieving limits of detection of <1 Bq/g. Validation of the procedure was assessed using a range of spiked matrices relevant to nuclear site decommissioning, reference materials and operationally-exposed materials. The compact size of this thermal extraction system is such that it allows for deployment in fume cupboards, gloveboxes and a mobile laboratory.

Optimization and validation of a procedure for the determination of tritium in gaseous effluents from nuclear power plants

Abstract The optimization and validation of a procedure for the determination of tritium from gaseous effluents from a nuclear power plant is described. Optimization included performance assessment of silica gel and a molecular sieve as a material for the adsorption of water moisture from air for continuous tritium sampling. In addition, the usability of such a system for monitoring tritium in laboratory air for low-level tritium measurements was assessed. The molecular sieve showed better performance, with an average desorption efficiency of 95% compared to 78% achieved with silica gel. The memory effect was also lower and more reproducible for the molecular sieve, amounting to 7% on average compared to 35% attained for silica gel. Measurement of low-level tritium in air showed the importance of prior checks of intrinsic tritium levels in the molecular sieve as due to that erroneous results could be produced.

A preparedness study: efficiency calibration and performance testing of LSC cocktails for determination of tritium in river‐water samples as an indicator of the technological start of a new NPP

The LSC instrument was efficiency calibrated for the tritium activity determination in river water samples by the direct measurement and different LSC cocktails were evaluated in the study. The combined standard uncertainty was around 6% at the coverage factor k = 1. The background tritium, total beta- and 137Cs activity concentrations in the Neris River samples were assessed. The obtained mean values were 1.5 Bq L− 1, 25 mBq L− 1, and 3.3 mBq L− 1 (MDA), respectively.

Tritium in the aquatic environment of Ozersk

Introduction. The article presents data on tritium concentrations in various types of aquatic environments (rainfall, snowfall, water from the Irtyash, B. Nanoga, Kyzyltash lakes, and the source of the Techa river, tap water, ice from the refrigerator, and urine) within the city of Ozersk and on the territory immediately adjacent to it in the impact zone of Mayak Production Center in the Southern Urals. Material and methods. For the quantitative determination of tritium in various aqueous media, sampling was carried out from 2002 to 2016. Samples were analyzed by the scintillation method using a single-stage electrolytic enrichment procedure. Results. Almost all aquatic environments in Ozersk in terms of their tritium content exceed the technogenic background established for the Ural region. On average, this excess is by 14, 11, 9, 19, 4, 6, 19 times for rainfall, snowfall, drinking water of residential premises, ice, the water of the Irtyash and B. Nanoga lakes, water from the source of the river Techa accordingly. Elevated concentrations of tritium in the urine of Ozersk people and the adjacent territory were noted in comparison with literature data for other regions of the world. Conclusion. The obtained research results revealed the levels of pollution of the aquatic environment of Ozersk with tritium relative to the level of technogenic background. These works indicate the need to develop a method for cleaning tritium emissions and discharges by nuclear enterprises to reduce the risk to the population.

Non-intrusive and reliable speciation of organically bound tritium in environmental matrices

Measurements of tritium in its various forms within the environment and especially in organic matter are keys to improving the current understanding of its environmental behavior and distribution. Validated or standardized analytical procedures for tritium determination methods have now been developed for several forms of tritium in environmental samples, yet an analytical lack remains regarding the quantifications of exchangeable and non-exchangeable forms of organically bound tritium (OBT) fractions. The present work therefore aims to provide a means of developing a standardized method for OBT fraction determination by evaluating the robustness and relevance of two methods (intrusive and non-intrusive methods) developed for non-exchangeable OBT quantification on a broad panel of pertinent environmental matrices. The validity and reliability of a non-intrusive method has thus been confirmed through a robust comparative study. Moreover, its relevance for standardization purposes is discussed, while the fundamental weakness of the conventional and most widespread method is highlighted and directly quantified for the first time in relying on many demonstrated biases.

Application of a liquid scintillation system with 100-ml counting vials for environmental tritium determination: Procedure optimization, performance test, and uncertainty analysis

For more efficient and accurate determination of airborne tritium in the environment, the procedure optimization, performance test and uncertainty analysis of a commercially available low-background liquid scintillation counting (LSC) system with 100-ml counting vials were studied in this work. The results showed that 50 ml water sample mixed with 50 ml scintillation cocktail (Ultima Gold uLLT, PE) could achieve the optimal counting condition after a dark adaption time longer than 1440 min. The minimum detectable activity (MDA) of the 100-ml vial system was estimated to be 0.18 Bq·L−1 in a continuous counting time of 3600 min, which was approximately 3.5 times lower than that of 20-ml vial system, and its determination uncertainty was also generally lower provided the collected samples was more than 15 ml. It indicates that the LSC system with 100-ml counting vials is preferable for environmental tritium determination. However, for more accurate determination, the electrolytic enrichment is still needed for the sample with the specific activity lower than 0.4 Bq·L−1. On the other hand, considering the cost and potential environmental impact of present available cocktails, the system with 20-ml vials is recommended for determining the sample with the specific activity higher than 2 Bq·L−1.

RO film-based pretreatment method for tritium determination by LSC

Tritium analysis in water is an important part of environmental radiation monitoring. At present, tritium in water is generally measured by liquid scintillation counting (LSC). To optimize the pretreatment process and improve the efficiency of tritium analysis via LSC, a pretreatment device for tritium analysis in water based on a reverse osmosis (RO) film was developed. This paper introduces the system composition and carries out the following experimental studies: First, the comprehensive performance of the device was studied by performing repeated analyses, and the pretreatment time can be reduced by approximately 77% compared with that of the traditional method; then, the device was used to process tritium samples with different concentrations to verify the negligible impact of any tritium residue in the RO film; finally, the reliability of the results is verified by comparing with the traditional atmospheric distillation pretreatment method under the same measurement conditions. The results showed the developed method has the advantages of a simple operation and a high degree of automation, which effectively improves the efficiency of tritium analysis in water.

New electrolytic enrichment system for tritium determination in water research institute in Bratislava and IT’S first results of tritium activity in precipitation

The method of tritium activity measurements by electrolytic enrichment in combination with liquid scintillation counting is well known for many years. In the Water Research Institute in Bratislava was this system employed since the 60-ties of the 20th century. In 2018 the laboratory of radiochemistry of Water Research Institute obtained a new electrolytic enrichment system with higher enrichment factor (varying from 9 to 22, depending on the total ampere-hours used). The enrichment factor of the previous system was about 6. Complementary to the new system, also the new LCS counter Quantulus GCT 6220 was added. This spectrometer has active background suppression function (Guard Compensation Technology - GCT) and for the tritium measurement the background counts decreased from cca. 9 cpm (for Tricarb 2900 TR) to approximately 1 cpm. To demonstrate the capabilities of this system, we present results of the tritium concentration in precipitations during the period from May 2016 to May 2019. The seasonal variations of tritium activities in precipitation are observed, with maximum values in spring season and minimum in winter. Additionally, selected tritium activities from the extensive monitoring of river waters in Slovakia are presented.

Application of the absolute method for determination of tritium and radiocarbon in groundwater from radioactive waste facility

The primary method was used for standardization and preparation of working solutions of 3H and 14C which were applied for calibration of the secondary instrument. Tritium and radiocarbon were assessed with the double-label counting of groundwater samples prepared for direct measurement. The combined uncertainty did not exceed 10% at low 222Rn activity concentrations.

Performance of nonylphenol-ethoxylates-free liquid scintillation cocktail for tritium determination in aqueous samples

The paper evaluates the performances of nonylphenol ethoxylates free cocktail (ProSafe LT+, Meridian Biotechnologies Ltd.) for tritium measurement using liquid scintillation counting and the laboratory’s routine procedure. The optimum ratio of sample and liquid scintillation cocktail for 20 ml vial volume was investigated, choosing a ratio of 8:12 ml of sample: scintillation cocktail. Good results were obtained for linearity (investigated between 0.3 MBq l−1 and 6 Bq l−1), repeatability, and trueness, and prove its applicability both for operation and environmental monitoring of tritium at nuclear facilities.

Investigation of the potential impact of storage place on tissue free water tritium and organically bound tritium activity determination

When focusing on environmental tritium measurement, water is the most common matrix, and monitoring is mainly concerned by tissue free water tritium (TFWT) and organically bound tritium (OBT) analysis. Moreover, in order to improve knowledge on tritium behaviour and migration, TFWT and OBT determinations are performed at low activity level. TFWT and OBT determinations could also be performed after incidental releases to determine potential impact to the environment and to man. As hydrogen isotopes are prone to isotopic exchange with atmospheric moisture, the key point when analysing TFWT and OBT is to ensure appropriate preservation of the sample from its sampling to its analysis.Aiming to answer to the following question: does the storage condition could change activity level within the sample? An interlaboratory exercise was organized within the framework of a French tritium working group to follow both TFWT and OBT activity scrutinizing for any variation on a one-year period. For this study about 50 kg of grass were sampled, homogenized, packaged and frozen prior dispatching to the participants. Six aliquots were sent to each participating lab to determine both TFWT and OBT activity concentrations, starting when all the labs received the sample, continuing two weeks, one month, three months, six months and one year after to check for any variation in the measured activity concentration.The results were treated for each analysis date, for each participating lab and considering the overall population by calculating the mean and associated standard deviation. As all values are consistent, the main conclusion of this work is that TFWT and OBT activity concentrations remain constant when appropriate storage conditions are used. This point is of importance as sample conservation is always a critical parameter for tritium determination in environmental samples and also when considering the fabrication of certified reference materials.

Determination of tritium in water using electrolytic enrichment: methodology improvements

The quality control of the method for tritium (3H) determination in water after electrolytic concentration by liquid scintillation counting measurements was improved considering more parameters in the uncertainty budget, besides the control charts to evaluate the electrolytic enrichment factor, the enrichment parameter and blank samples. The quality control upgrade of the method and the participation in proficiency tests allow its optimization. This methodology was applied to the determination of 3H activity concentrations in waters from different origins: surface, rain and drinking waters.

Tritium in organic matter around Krško Nuclear Power Plant

The aim of the research was to obtain first results of tritium in the organic matter of environmental samples in the vicinity of Krsko NPP. The emphasis was on the layout of suitable sampling network of crops and fruits in nearby agricultural area. Method for determination of tritium in organic matter in the form of Tissue Free Water Tritium (TFWT) and Organically Bound Tritium (OBT) has been implemented. Capabilities of the methods were tested on real environmental samples and its findings were compared to modeled activities of tritium from atmospheric releases and literature based results of TFWT and OBT.

A Suite of Robust Radioanalytical Techniques for the Determination of Tritium and Other Volatile Radionuclides in Decommissioning Wastes and Environmental Matrices

Tritium is ubiquitous in and around nuclear plants, being formed via neutron capture by 2H, 6Li, 10B and 14N and via ternary fission. The highly mobile nature of 3H species results in widespread distribution of the radionuclide. Predictive modeling of 3H activity concentrations is challenging and direct measurement of 3H activities in materials is the preferred approach to underpin waste and environmental assessments. For well over a decade, the UK nuclear industry has engaged in a significant program of site decommissioning of its first generation reactors. This has resulted in a high demand for the rapid characterization of 3H in a diverse range of matrices, including concretes, metals, plastics, sludges, resins, soils and biota. To support such assessments, it has been necessary to develop dedicated instrumentation in parallel with robust radioanalytical methodologies; namely a multi-tube furnace and a high-capacity, closed (pressurized) oxygen combustion system. Data are presented on the development and validation of these instruments, designed specifically to enable the quantitative extraction of 3H (and other volatile radionuclides) from diverse sample types. Furthermore the furnace system has been employed as a tool to gain insights into the 3H association in decommissioning and environmental matrices exposed to 3H arising from nuclear power plant operations through tritium evolution with temperature profiling. The impact of the chemical speciation of 3H on analytical strategy is discussed. A major benefit of the multi-sample furnace is its ease of use and applicability to 3H determination in virtually any sample type. The complementary HBO2 oxygen combustion system has been developed for the quantitative oxidation of organic-rich samples (e.g. wood, plastic, oil, biota) and analytical data prove its effectiveness.