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A cryogenic liquid-tritium target was developed by RFNC−VNIIEF for studying ptμ fusion. In 2016, it was regularly used for more than 270 h on the muon channel of the JINR Phasotron, thus confirming the compliance with the specified requirements and the correctness of the proposed engineering solutions. At a maximum operating pressure of 4 MPa, an irradiated ampoule volume as large as 80 cm3, and three lines of protection, the target was able to liquefy up to 40 L of a hydrogen-isotope mixture and maintain a temperature in the range of 20−22 K with an accuracy of ±0.05 K or better. Based on the results of the ptμ‑fusion experiments, the reaction channel with the emission of electron−positron pairs was detected for the first time and evidence for the existence of a new reaction channel with the emission of a pair of γ-ray photons was obtained.

The article presents results of comparative tests for the determination of deuterium fluxes permeating through walls of austenitic stainless steel AISI304 (DIN 1.4301) chamber and Al{sub 2}O{sub 3} based ceramic F99.7 chamber. Both chambers represent a piece of φ(ext)=26*φ(int)=22*117 mm{sup 3} tube with spherical bottom ending. It is shown that at 773 K and deuterium pressure of 1200 mbar the permeated deuterium flux through the stainless steel chamber constituted 8*10{sup -5} cm{sup 3}/s, while the flux through ceramic one it did not exceed the sensitivity of the measurement method threshold, namely about 1.5*10{sup -7} cm{sup 3}/s. The ceramic chamber turned out to survive more than 10{sup 3} cycles of heating up to 773 K with no damages. It did not lose its tightness up to 10 bar of internal deuterium pressure. The authors also present test results of a prototype bed for reversible tritium storage. The bed's case was made of alumina based ceramic F99.7, titanium being used as tritide making metal and high frequency induction used for heating the tritide metal. (authors)

The long-term contact of structural materials (SM) with tritium-containing media makes their properties in terms of kinetic permeability of hydrogen isotopes change. This change is the consequence of the defect formation in SM due to the result of {sup 3}He build-up generated by the radioactive decay of tritium dissolved in SM. This paper presents the experimental results concerning the permeability of hydrogen isotopes through CrNi35WTiAl alloy containing {sup 3}He and the impact of the presence of {sup 3}He and H on its mechanical properties. Tensile tests of cylindrical samples containing various concentrations of {sup 3}He (90, 230 and 560 appm) have been performed in inert and hydrogen atmospheres. The build-up of {sup 3}He has been made using the 'helium trick' technique. The maximal decrease in the plastic characteristics of the CrNi35WTiAl alloy occurs in samples with the highest {sup 3}He (560 appm) content at 873 K. The permeability of deuterium through the CrNi35WTiAl alloy in the initial state and that with 560 appm of {sup 3}He content was explored. The presence of this {sup 3}He concentration has shown an increase in deuterium permeability, evidently due to structural changes in the material under the impact of radiogenic helium.

The muon-catalyzed fusion (μCF) process in tritium was studied by the μCF collaboration on the muon beam of the JINR Phasotron. The measurements were carried out with a liquid tritium target at the temperature 22 K and density approximately 1.25 of the liquid hydrogen density (LHD). Parameters of the μCF cycle were determined: the ttμ muonic molecule formation rate λ ttμ = 2.84(0.32) μs−1, the ttμ fusion reaction rate λ f = 15.6(2.0) μs−1, and the probability of muon sticking to helium ω tt = 13.9(1.5)%. The results agree with those obtained earlier by other groups, but better accuracy was achieved due to our unique experimental method.

Automated system feeding into ion source hydrogen isotopes as molecules with preset ratio of the fluxes is described. The control system automatically maintained the working parameters and provided graphic and digital representation of the controlled processes. Theradio-frequency (RF) ion source installed at the axial injection line of the cyclotron produced ion beams of HD + , HT + , DT + , D 2 H + , etc. At a several months DT + beam acceleration the tritium consumption was less than 108 Bq/hr. The intensity of a 58.2 MeV triton beam (T + ions) extracted from the cyclotron chamber was about 10 nA.

The superpermeability phenomenon was suggested to use in fusion machines to separate the fuel mixture from helium ashes, to arrange in-vessel fuel recirculation contours and effective evacuation of...

To develop the membrane pumping technology by means of superpermeable membranes at RFNC-VNIIEF in the “Prometheus” setup, the experiments on superpermeation of hydrogen isotopes through metal membr...

Apparatus being developed at the Russian Federal Nuclear Center-VNIIEF for research of tritium retention in and permeation through metals and structural materials is described. The apparatus is composed of two combined research complexes involved in the solution of related scientific problems. The first problem is to study tritium superpermeability through metal membranes. The second — is to investigate tritium permeation through and retention by structural materials, to search and analyze protective coatings which increase safety of tritium-bearing gas media application.

The experimental setup is put in operation designed to study the phenomenon of the superpermeation of hydrogen isotopes, including tritium, through metals and to demonstrate the possibility of membrane pumping. The permeation of atomic hydrogen through the niobium membrane was shown to occur in the superpermeation regime. For the first time superpermeation of tritium through a metallic membrane was experimentally observed. The possibility of effective pumping, compression and recuperation of hydrogen isotopes by means of superpermeable membrane was demonstrated.