Introduction Of Tritium Research Articles

Preparation of high-labeled graphene oxide by tritium thermal activation method for application in the betavoltaic cell of a nuclear battery

Possibility of tritium introduction into graphene oxide (GO) by tritium thermal activation method was demonstrated. It has been established that, in order to obtain the highest possible specific radioactivity, thin films of GO with a thickness of 5.6 mg/m2 must be treated with tritium atoms. The experiment provided at 77 K showed a number of advantages. Under these conditions, the specific activity of [3H]GO of 2.6 Ci/mg was reached when calculated by the mass of the initial GO (0.7 Ci/mg if purified to remove the labile tritium). Specific energy release in [3H]GO with such specific activity is 22.3 W/kg, which is enough for its application as a component of an atomic battery.

Preparation of High-Labeled Graphene Oxide by Tritium Thermal Activation Method for Application in the Betavoltaic Cell of a Nuclear Battery

The possibility of tritium introduction into graphene oxide (GO) by tritium thermal activation method was demonstrated. It was established that, in order to produce the highest possible specific radioactivity, thin films of GO with a thickness of 5.6 mg/m2 must be treated with tritium atoms. The experiment conducted at 77 K showed a number of advantages. GO was processed with tritium atoms, the resulting specific activity of [3H]GO reached 2.6 Ci/mg in term of the weight of the initial GO (0.7 Ci/mg after removal of the labile tritium). Specific energy release of [3H]GO with this specific activity is 22.3 W/kg, which is quite sufficient for its application as a component of a nuclear battery.

Effect of Graphene Oxide and Carbon Nanotubes on the Reaction of Tritium Atoms with Dalargin

Effect of carbon substrates materials (graphene oxide, reduced graphene oxide, single-walled carbon nanotubes) on the result of tritium introduction into dalargin peptide was studied by the thermal activation method. It was shown that, when dalargin is deposited onto carbon substrates, the distribution of tritium over amino-acid residues strongly changes as compared with a thick target deposited directly onto glass walls of a vessel. It was demonstrated that, when dalargin is deposited onto the carbon materials studied, the content of tritium in phenylalanine substantially increases, which indicates that the isotope exchange reaction occurs by the electrophilic mechanism. It was also found that the content of tritium in other amino-acid residues substantially changes, which is due to the difference between the structures of adsorption layers of the peptide, formed n the carbon materials under consideration.

Synthesis of Tritiated Glutamic Acid and Pyroglutamate

It was shown that introduction of tritium directly into glutamic acid does not afford a highly labeled product (at 160°C, a specimen with a specific radioactivity of 3–5 Ci/mmol was formed; at 180°C, the specific radioactivity was 26 Ci/mmol; and at 200°C, the compound strongly degraded). Heating a mixture of 5% Pd/Al2O3 with alumina-supported sodium glutamate at 220°C for 7.5 min gave mainly [3H]pyroglutamate. After isolation and purification of [3H]pyroglutamate, its solution in 1 N HCl was heated at 105°C for 20 h. This yielded [3H]glutamic acid with a specific radioactivity of 40 Ci/mmol.

Tritium-labeled 5-oxo-Pro-Arg-Pro

Conditions of tritium introduction into 5-oxo-Pro-Arg-Pro have been developed. Labelled 5-oxo-Pro-Arg-Pro has been obtained in 75% yield and molar radioactivity of 60 Ci/mmol. Tritium distribution over amino acid residues in the peptide has been determined. 5-Oxo-Pro : Arg : Pro ratio in the labelled peptide has been found to be 1 : 5.2 : 2.8. Nonterminal amino acid has been found to contain the major portion of tritium, about 35 Ci/mmol; i.e., arginine includes more than half of the label. Such a feature can be explained by the effect of readily protonated guanidine group of arginine. The influence of charged guanidine group of arginine seems to increase the shift of electron density in the neighboring C–H bonds of arginine and proton mobility, thus increasing protium–tritium exchange at these carbon atoms.

Operational aspects of the JET tritium introduction modules

As part of the JET Programme in Support for ITER, campaigns with pure Tritium (TT) fuel and Deuterium-Tritium (DT) mixtures are planned at JET. Unlike previous DT campaigns a much higher tritium flow rate, particularly during TT operation, is required. Five Tritium Introduction Modules (TIMs), fed from the Active Gas Handling System (AGHS), are to be installed; three in the divertor region, one in the mid-plane and another at the top of the machine. The selected TIM locations, the design and operational characteristics, were chosen so that most of the existing deuterium experiments can be replicated in tritium.The purpose of the TIMs is to supply precisely controlled quantities of tritium to the JET machine and this is achieved by controlling the piezoelectric valve openings. These control valves are located after the reservoir volumes, which contain tritium at sub-atmospheric pressure (charged initially to ∼800mbar). Prototype piezoelectric valves developed by VAT Vacuumvalves AG, require an estimated stroke of 160μm for the valve orifice area of 5.2mm2. These valves are at present being tested, with the aim of delivering a maximum flow of 1.6bar.l/s with tritium at 800mbar.This paper presents statistics to justify the operational requirements and details the TIM design including the operation sequence.

Technical rehearsal of tritium operation at JET

The final phase of the JET Programme in Support of ITER plans to operate with 100% tritium (TT) followed by deuterium-tritium (DT) operation, to help minimise risks and delays in the execution of the ITER Research Plan and the achievement of a fusion gain Q∼10. In preparation for tritium operation, an 8-week technical rehearsal of the procedures and systems is being executed in 2015-16. The aim is to commission (in deuterium or hydrogen) and characterise the NBI performance with a tritium-like gas feed configuration, test the prototype tritium introduction module, commission the torus hall depression and oxygen depletion system, carry out emergency exercises, train personnel and to test and optimise operational procedures. The rehearsal demonstrated that JET is still capable of operating with tritium in a safe and reliable manner, and most importantly, provided operational experience and lead to recommendations for the preparation of these future tritium campaigns on JET.

Dependency of irradiation damage density on tritium migration behaviors in Li2TiO3

Tritium migration behaviors in Li2TiO3 with the increase of irradiation damage density were investigated by means of electron spin resonance and thermal desorption spectroscopy. The irradiation damages of F+-centers and O−-centers were formed by neutron irradiation, and their damage densities were increased with increasing neutron fluence. Tritium release temperature was clearly shifted toward higher temperature side with increasing neutron fluence, i.e. increasing damage density. The rate determining process for tritium release was also clearly changed depending on the damage density. Tritium release was mainly controlled by tritium diffusion process in crystalline grain of Li2TiO3 at lower neutron fluence. The apparent tritium diffusivity was reduced as the damage density in Li2TiO3 increased due to the introduction of tritium trapping/detrapping sites for diffusing tritium. Then, tritium trapping/detrapping processes began to control the overall tritium release with further damage introductions as the amount of tritium trapping sites increased enough to trap most of tritium in Li2TiO3. The effects of water vapor in purge gas on tritium release behaviors were also investigated. It was considered that hydrogen isotopes in purge gas would be dissociated and adsorbed on the surface of Li2TiO3. Then, hydrogen isotopes diffused inward Li2TiO3 would occupy the tritium trapping sites before diffusing tritium reaches to these sites, promoting apparent tritium diffusion consequently. Kinetics analysis of tritium release for highly damaged Li2TiO3 showed that the rate determining process of tritium release was the detrapping process of tritium formed as hydroxyl groups. The rate of tritium detrapping as hydroxyl groups was determined by the kinetic analysis, and was comparable to tritium release kinetics for Li2O, LiOH and Li4TiO4. The dangling oxygen atoms (O−-centers) formed by neutron irradiation would contribute strongly on the formation of hydroxyl groups. The efficiency of tritium trapping/detrapping by the dangling oxygen atoms was clearly increased with increasing damage density due to the stabilization of damages by neighboring irradiation damages and/or the lithium burn-up which produces lithium vacancy acting as a pass way of tritium to the dangling oxygen atoms.

Tritium fuel cycle in ITER and DEMO: Issues in handling large amount of fuel

Abstract Since tritium resources are very limited, economical conversion of fusion energy to electricity and/or heat must have an enough margin to keep self-fuel-sufficiency and simultaneously ensure tritium safety. To realize this, tritium inventory in reactor systems, which use ∼10 17 Bq (a few kg) of tritium, should be kept as small as possible, under strict accountancy or regulation of a few tens Bq (∼pg). In present tokamaks, however, hydrogen retention rate is significantly large, i.e. more than 5% of fueled hydrogen is continuously piled up in their vacuum vessels, which must not be allowed in a reactor. Moreover, both fuelling and burning efficiencies are very poor, only a few % or less. Accordingly, huge amount of tritium fuel must be recycled. In the paper, after the introduction of tritium as a hydrogen radioisotope, important issues to establish safe and economical tritium fuel cycle for a fusion reactor will be summarized considering the handling of large amounts of tritium, i.e. confinement, leakage, contamination, permeation, regulation and tritium accountancy.

Increase in the specific radioactivity of tritium-labeled compounds obtained by tritium thermal activation method

Abstract A method of tritium introduction into different types of organic molecules that is based on the interaction of atomic tritium with solid organic target is described. Tritium atoms are formed on the hot W-wire, which is heated by the electric current. Such an approach is called “tritium thermal activation method”. Here we summarize the results of labeling globular proteins (lysozyme, human and bovine serum albumins); derivatives of pantothenic acid and amino acids; ionic surfactants (sodium dodecylsulfate and alkyltrimethylammonium bromides) and nonionic high-molecular weight surfactants – pluronics. For the first time it is observed that if the target-compound is fixed and its radicals are stable the specific radioactivity of the labeled product can be drastically increased (up to 400 times) when the target temperature is ca. 295 K compared with the results obtained at 77 K. The influence of labeling parameters as tritium gas pressure, exposure time and W-wire temperature was tested for each target temperature that results in the optimum labeling conditions with high specific radioactivity and chemical yield of the resulting compound.

Tritium introduction from a cooling water reservoir in sources of drinking water supply by filtration through deep layers of underlying rocks

Tritium introduction from a cooling water reservoir in sources of drinking water supply by filtration through deep layers of underlying rocks

Changes of the breaking strain from content of tritium and cycling in a palladium cathode membrane

In this work, it is examined the breaking strain in the function of the tritide phases, of depth and surfaces of silver alloyed or not alloyed palladium cathode membrane in a sequential process for penetration of tritium. Examining the parameters, a mapping model is given. Firstly, the introduction of tritium in the membrane by electrolytic cracking of tritiated water with cycling leads to high constant breaking strain in the adsorption surface and an increase of the breaking strain in the desorption surface. The tendency towards numerous cracks formation on the two surfaces is indisputable. Secondly, a progressive decrease of breaking strain in the depth of membrane, independent of cycling, signifies decelerating cracks and fractures in the volume of palladium. Before shutdowns of electrolysis and temperature, tritium purging process is recommended to avoid inversion of phase in entry and exit surfaces then collapse to increase the life of the palladium membrane. Porous ceramic support prevails on the life of palladium membrane.

Tritium handling issues in fusion reactor materials

In order to establish a D–T fusion reactor as an energy source, it is not enough to have a D–T burning plasma, and economical conversion of fusion energy to electricity and/or heat, a large enough margin of tritium breeding and tritium safety must be simultaneously achieved. In particular, handling of huge amount of tritium needs significant efforts to ensure that the radiation dose of radiological workers and of the public is below the limits specified by the International Commission on Radiological Protection (ICRP). In this paper, after the introduction of tritium as a fuel of DT reactors and as a radioisotope of hydrogen, tritium safety issues in fusion reactor materials, are summarized focusing onto tritium retention, permeation and contamination.

The efficiency of solvent‐free catalyst systems in the synthesis of tritium‐labelled biologically active compounds

AbstractModern theories about the processes that take place inside solvent‐free catalyst systems are considered and the various factors that have an effect on the successful introduction of tritium into organic compounds are summarized. Obtaining labelled compounds using solvent‐free catalyst systems, liquid‐phase methods, and isotopic exchange with tritiated water are all regarded as various manifestations of the same set of occurrences in the presence of tritium, a substrate and a catalyst. The use of various isotopic exchange methods has made possible the introduction of tritium into practically any type of biologically active compound. This will enable scientists to carry out more detailed studies of the processes inside living organisms. Copyright © 2010 John Wiley & Sons, Ltd.

Scintillation phase method: A new approach for studying surfactant behavior at liquid/liquid interface

Radiochemical approach for the investigation of partitioning and adsorption of surfactants at water-oil interfaces has been developed. The so-called “scintillation phase method” is based on the introduction of tritium labeled surfactant in an aqueous phase of the water-oil system followed by measuring radioactivity of the whole system. Partition coefficients and the value of adsorption at water-non-polar liquid interfaces of homologous series of alkyltrimethylammonium bromides (DTAB, TTAB and CTAB) have been experimentally determined by means of scintillation phase method. The influence of non-ionic surfactants on TTAB adsorption has also been studied.

The acrosomal membrane system of boar spermatozoa--morphological and biochemical studies.

The distribution of the cell surface saccharides with alpha-glycosidically linked mannose and terminal galactose was displayed by fluorescence microscopical examinations with FITC-conjugated concanavalin A and Ricinus communis agglutinin-120. The lectin binding sites of the inner cellular membranes--inner and outer acrosomal membrane--were ultrastructurally localized by electron microscopical studies using the lectin-peroxidase technique. It could be demonstrated that both acrosomal membranes contain covalently bound carbohydrates. In order to characterize the acrosomal membrane components which are responsible for the binding to lectins, the outer acrosomal membrane was separated after homogenization by centrifugation through modified colloidal silica. The exposed membrane proteins were labelled by galactose oxidase mediated introduction of tritium into the carbohydrate side chains of the glycoproteins. After solubilization the membrane components were analysed by affinity chromatography and electrophoresis. For a general characterization the cholesterol/phospholipid ratio of ejaculated boar spermatozoa and the isolated membrane fraction was determined and some enzymatic activities were assessed.

Technical and Scientific Aspects of the JET Trace-Tritium Experimental Campaign

The JET Trace Tritium (TTE) programme marked the first use of tritium in experiments under the managerial control of UKAEA, which operates the JET Facility on behalf of EFDA. The introduction of tritium into the plasma by gas fuelling and neutral beam injection, even in trace quantities, required the mobilisation of gram-quantities of tritium gas from the Active Gas Handling System (AGHS) product storage units into the supply lines connected to the torus gas valve and the neutral beam injectors. All systems for DT gas handling, recovery and reprocessing were therefore recommissioned and operating procedures re-established, involving extensive operations staff training. The validation of Key Safety Related Equipment (KSRE) is described with reference to specific examples. The differences between requirements for TTE and full DT operations are shown to be relatively small. The scientific motivation for TTE, such as the possibility to obtain high-quality measurements in key areas such as fuel-ion transport and fast ion dynamics, is described, and the re-establishment and development of JET’s 14MeV neutron diagnostic capability for TTE and future DT campaigns are outlined. Some scientific highlights from the TTE campaign are presented.

Helium Nano-Bubble Evolution in Aging Metal Tritides

A continuum-scale, evolutionary model of bubble nucleation, growth and He release for aging metal tritides is described which accounts for major features of the tritide database. Bubble nucleation, modeled as self-trapping of interstitially diffusing He atoms, occurs during the first few days following tritium introduction into the metal. Bubble growth by dislocation loop punching yields good agreement between He atomic volumes and bubble pressures determined from bulk swelling and 3He NMR data. The bubble spacing distribution determined from NMR is shown to remain fixed with age, justifying the separation of nucleation and growth phases and providing a sensitive test of the growth formulation. Late in life, bubble interactions are proposed to produce cooperative stress effects, which lower the bubble pressure. Helium generated near surfaces and surface-connected porosity accounts for the low-level early helium release. Use of an average ligament stress criterion predicts an onset of inter-bubble fracture in good agreement with the He/Metal ratio observed for rapid He release. From the model, it is concluded that He retention can be controlled through control of bubble nucleation.

Synthesis of tritium and carbon‐14 labelled NNC 61‐4655: a potent dual‐acting PPARα and PPARγ agonist

AbstractThe synthesis of the potent dual‐acting PPARα and PPARγ agonist NNC 61‐4655 labelled with tritium and carbon‐14 is reported. Tritium labelled NNC 61‐4655 was obtained in three steps with introduction of tritium through catalytic tritium‐halogen exchange of an aryl bromide precursor. This provided [3H]NNC 61‐4655 in 39% overall radiochemical yield with a specific activity of 49 Ci/mmol. Carbon‐14 labelled NNC 61‐4655 was obtained in five steps starting from bromo[1‐14C]acetic acid. The synthetic sequence, which included a Horner–Wadsworth–Emmons olefination and a Mitsunobu alkylation, provided [14C]NNC 61‐4655 in 33% overall radiochemical yield with a specific activity of 57.4 mCi/mmol. Copyright © 2003 John Wiley & Sons, Ltd.

Tritiated amorphous silicon betavoltaic devices

The introduction of tritium into hydrogenated amorphous silicon has given rise to a novel material with interesting physical properties and potential applications. Tritium undergoes radioactive decay, transforming into 3He+ and emitting an electron with average energy 5.7 keV, at a rate equivalent to a half-life of 12.3 years. The decay of tritium results in the creation of electron–hole pairs and in the formation of dangling bonds. Infrared spectroscopy and effusion measurements were used to analyse tritium bonding in the silicon network. Electron spin resonance and photoluminescence of tritiated amorphous silicon were examined as a function of time to study the evolution of dangling bonds. Thermal annealing was used to study metastability of dangling bonds in the material. Electrical characteristics of pin diodes containing tritium in the intrinsic layer were investigated. The application of tritiated–hydrogenated amorphous silicon in betavoltaic devices is presented.