The features of hydrogen trapping under the irradiation of zirconium alloys E110 and E635 with an electron beam (400 eV, 0.8 mA/cm 2 ) in various gaseous ambient containing oxygen and hydrogen (Ar + O 2 + H 2 ; Ar + H 2 O) are studied. The effect of surface temperature on the hydrogenation of zirconium alloys under electron irradiation is studied. It is shown that neither exposure nor electron irradiation in a gaseous ambient containing a mixture of H 2 and O 2 at 700 K for 20 h leads to a change in the hydrogen level in the E110 alloy, while hydrogen partially escapes from the E635 alloy during the experiment. The amount of hydrogen in zirconium alloys after exposure in a gaseous ambient containing H 2 O in a similar temperature–time regime also changes insignificantly; however, if the alloys are irradiated with electrons under these conditions, then they contain 1.5–2 times more hydrogen. When temperature of the samples is raised to 900 K, electron irradiation in the presence of water vapor, on the contrary, reduces the trapping of hydrogen in the E110 and E635 alloys, compared with exposure in the same gaseous ambient without irradiation. It is concluded that electron irradiation affects the balance of surface reactions of formation of hydroxyl groups from adsorbed water molecules and reverse reactions of formation of water molecules from surface hydroxyls. The direction of shifting the balance of these reactions depends on the surface temperature.

In the article, a hydrogen exchange between the Zr-1%Nb alloy (E110) and the gas ambient was experimentally studied when the samples were irradiated with deuterium and argon plasma ions. It has been established that, upon irradiation with deuterium plasma ions with an energy of E = 650 eV/at, the enhanced absorption of deuterium exceeds the release of hydrogen initially contained in the samples, which leads to their loading with hydrogen isotopes. Adding 30 at.% oxygen to the plasma-forming gas or raising the sample temperature from T = 450 K to T = 600 K, significantly reduces the content of hydrogen isotopes in the sample. Based on the aggregate data obtained by atomic and ion irradiation, a mechanism of hydrogen exchange between zirconium alloy and gas ambient is proposed. The process includes three stages: reactions on the oxidized surface of the zirconium alloy (surface hydroxylation and formation of water molecules); reactions at the metal-oxide interface; transfer of hydrogen isotopes through the surface oxide layer in both directions due to hopping between neighboring oxygen ions. Surface reactions caused by irradiation of atoms and ions trigger the hydrogen exchange. The proposed model agrees with the experimental data on the irradiation of the E110 alloy with atoms and ions of hydrogen isotopes.

In this work, thermal-desorption spectrometry is used to study Be–W and Al–W intermetallic compounds formed on the surface of tungsten during the deposition of Be and Al atoms evaporated in the temperature range of 400–500 K, as well as Al atoms sputtered in argon plasma. Due to safety limitations imposed on work with beryllium in the university laboratory, most of the experiments are carried out with aluminum which is one of the proxy materials to beryllium. Regularities for the formation of intermetallics in the surface layer of tungsten during the deposition of Al and Be atoms, and in the layer formed during the joint deposition of Al and W atoms on tungsten are described. The features of the trapping of argon and hydrogen into the intermetallics are analyzed for different fluences of Al atoms deposited in plasma on the surface of tungsten, as well as for different concentrations of components in the deposition flux during the simultaneous deposition of Al and W atoms on tungsten. The features of the Al–W intermetallic formation and the nature of the retention and desorption of gases during the deposition of evaporated and plasma-sputtered aluminum atoms on tungsten are revealed. The release of a significant part of hydrogen from the Al–W intermetallic under irradiation with 50 eV ions of deuterium plasma at a temperature of 500 K is found. Most of the gases trapped by Be–W and Al–W intermetallics is desorbed in the interval of 1200–1600 K during intermetallics decomposition.

The paper investigates the trapping and desorption of hydrogen isotopes under irradiation of zirconium alloy E110 with ions of deuterium plasma. It is established that, under the irradiation, hydrogen exchange between the alloy and the gaseous ambient occurs: part of deuterium from the irradiation flux is trapped by the alloy, and at the same time, hydrogen initially contained in the alloy is partially desorbed. In general, hydrogen exchange results in an increase in the content of hydrogen isotopes in the sample. Addition of 30 at

The features of oxidation and hydrogenation of zirconium alloy E110 under electron and plasma irradiation in various conditions are studied. It is revealed that irradiation intensifies both the oxide layer growth and the hydrogen absorption by zirconium. Applying the anode potential on the E110 sample in plasma allowed to achieve the maximum rates of these processes and at the same time to reproduce their characteristic features exhibited in traditional steam tests. This circumstance determines the choice of plasma anodizing as a perspective basis for the method of accelerated testing of Zr alloys.

In this work we investigated the possibility of increasing the efficiency of aluminum oxide protective coating on EP-823 steel by applying a sublayer consisted of aluminum and steel components before the coating deposition. It is shown that Fe-Cr-Al sublayer is able to prevent the steel corrosion in a molten lead flow in the case of damage of the oxide coating. In addition, the sublayer reduces the risk of delamination of aluminum oxide and slows down the transport of iron atoms from the steel towards the surface.

In this work, the results of the irradiation of untreated, preliminarily Ar+-bombarded and Cr-coated samples of zirconium alloy E110 (Zr-1%Nb) with deuterium atoms and ions of deuterium plasma were compared with the results of their exposure to superheated water steam (673 K, 11 MPa; 673 K, 0.1 MPa; 633 K, 0.1 MPa). It was concluded that, despite of the difference in the rates of the oxide layer formation, the features of hydrogenation are similar under the two kinds of impact. However, the hydrogen uptake under irradiation occurs hundreds of times faster than during the steam test. The most effective hydrogenation was achieved under irradiation of the E110 sample with 300-500 eV/at ions of deuterium plasma without oxygen. These circumstances allow suggesting the irradiation with ions of hydrogen plasma as an accelerated hydrogenation test of zirconium alloys and protective coatings under conditions simulating the environment of light-water reactor's core. The proposed method could be realized using a simple plasma device and it does not require high power consumption or special qualification of staff. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Features of plasma-induced formation of the surface oxide layers on zirconium alloy E110 (Zr-1%Nb) as well as hydrogen resistant properties of these layers are studied. It is shown that irradiation of the E110 sample with 1 keV ions of He + O-2 plasma produces the oxide layer depleted by oxygen nearby the surface. The onset of the intensive hydrogen penetration into the ion-irradiated sample during the steam test (673 K, 0.1 MPa) appears to occur 1500 hours later than into the untreated one.

The ability of yttria layers to act as barriers to hydrogen desorption is studied. The possibility is discussed of using these layers to reduce losses of tritium from a neutron tube target. The composition of a multilayer target in which tritium desorption is reduced by an accumulator layer (zirconium) and barrier layers (yttria) is described. It is shown that deuterium losses observed in thermal desorption tests over 4 h at 623 K fell by 85–87%. A system is proposed for the renewal of an external barrier layer subjected to sputtering by a deuteron ion flux.

Patterns of hydrogen isotope trapping and retention are investigated by applying hydrogen ion radiation to nickel samples free of oxidation, tungsten samples with oxide layer on their surfaces, and tungsten samples with aluminum coating with oxide layer. It is found that hydrogen isotope desorption upon hydrogen ion plasma irradiation occurs in samples of tungsten and tungsten with aluminum coating, but not in nickel samples. It is concluded that hydrogen isotope transport through the tungsten–aluminum interface is initiated when one surface of a samples is irradiated with hydrogen plasma ions.

Acceleration of hydrogen isotope trapping and desorption has been observed in the experiments with stainless steel (Activated Surface Penetration - ASP) under irradiation by hydrogen atoms and hydrogen plasma ions with oxygen impurity. ASP is considered in this paper for a method of low-temperature hydrogen isotope removal from tungsten and aluminum-coated tungsten under irradiation by hydrogen plasma ions with oxygen impurity. It is shown that periodic irradiation by hydrogen plasma ions with oxygen impurity allows preventing accumulation of implanted deuterium ions in tungsten.

An investigation on mechanisms of hydrogen and deuterium trapping in tungsten during irradiation by hydrogen ion plasma with oxygen impurity using the methods of thermal desorption spectrometry (TDS) and secondary ion mass spectrometry (SIMS) is presented in this paper. It was shown that almost 40% of trapped particles were retained in the surface oxide layer after first implantation of deuterium. Subsequent irradiation by hydrogen plasma with oxygen impurity lead to the increase of oxygen concentration and hydrogen trapping in the oxide layer and tungsten bulk. In the next cycle, which started with deuterium implantation, oxygen concentration in the oxide layer decreased and some hydrogen was removed from tungsten. Then an increase of hydrogen and oxygen concentration in the sample repeated during irradiation with ions of (H2 + 1 at. % O2) plasma. The same sequence of processes was observed during subsequent irradiation cycles.

The results of the comparative analysis of low-temperature desorption of deuterium from tungsten coated with aluminum and yttrium films under the irradiation by hydrogen plasma with oxygen impurity are presented. The irradiation of aluminum or yttrium coating by H2+1%O2 plasma leads to the desorption of implanted deuterium from the samples. It was shown that the number of atoms desorbed depends on the sign of enthalpy of hydrogen solution in the metal film.

Effect of yttria and titanium nitride coatings on features of deuterium desorption from titanium layer is investigated. It is shown that both coatings significantly raise the temperature of maximum of deuterium thermal desorption from titanium under linear heating and prevent desorption under prolonged keeping at the operating temperature of a neutron tube target. However, under irradiation with ions of H-2 + O-2 plasma the barrier properties of titanium nitride appear to degrade.

Effect of zirconium irradiation by 1 keV Ar+ ions on hydrogen transport through the surface oxide layer is studied. It is shown that deuterium trapping under subsequent irradiation of the Ar-treated sample by deuterium atoms of thermal energies in D2 + 30at.% O2 gas mixture is 2 times less than trapping in the untreated sample. Besides, irradiation of the untreated sample by D-atoms provokes desorption of ≈25% of hydrogen contained therein, whereas hydrogen desorption from the ion-treated zirconium surface does not occur. It is proposed that oxygen depletion of the surface oxide layer, caused by ion bombardment, is a reason of mitigation of the hydrogen transport through this layer in both directions.