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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)

Приводятся основные результаты работ по созданию экспериментальной базы, позволяющей безопасно проводить фундаментальные и прикладные исследования с тритийсодержащими средами в условиях неспециализированных лабораторий. Обсуждаются технические характеристики комплексов оборудования и установок, методические подходы, обеспечившие проведение исследований: явления мюонного катализа ядерных реакций синтеза; свойств лёгких экзотических ядер на границе нейтронной стабильности; явления «сверхпроницаемости» трития через металлы V группы и проницаемости водорода через конструкционные материалы, в том числе содержащие радиогенный Не; взаимодействия конструкционных материалов с изотопами водорода, включая тритий при давлении до 300 МПа.

The paper presents research results related to the impact of high-pressure hydrogen (80 MPa) and radiogenic 3He and their synergetic effect on mechanical properties and structure of CrNi40MoCuTiAl alloy within the temperature range from room temperature to 873K.The samples of three different 3He concentrations have been prepared for research: ≈ 30, ≈ 80 and ≈ 190 appm. The buildup of 3He has been fulfilled using «tritium trick» technique.The tests at room temperature have shown the increasing conventional yield strength (σ0.2) and decreasing plasticity characteristics (total elongation Δ5 and reduction of area E) depend on 3He concentration increasing. However at 873 К test temperature the alloy with the maximum 3He (≈ 190 appm) concentration turned out to be more plastic than the alloy with 3He ≈ 30 and 80 appm concentration.

A search for the muon-catalyzed fusion reaction d + d → 4He + γ in the ddμ muonic molecule was performed using the experimental installation TRITON with BGO detectors for γ-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect γ-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the ddμ state J = 1 was obtained at the level of ηγ ≤ 8 × 10−7 per fusion.

The thermodynamic properties of a highly compressed deuterium plasma have been measured using an explosive spherical experimental chamber. The experiment has been performed with an X-ray diffraction complex consisting of three betatrons and a multichannel optoelectronic system of the detection of X-ray images of the process of the explosive spherical compression of deuterium. The density of the shock-compressed deuterium plasma ρ = (4.3 ± 0.7) g/cm3 at the pressure P = 1830 GPa has been detected at the initial pressure of gaseous deuterium P 0 = 267 atm and the temperature T 0 = 10.5°C. Under such conditions, the plasma is strongly nonideal (Γ ∼ 450) with the degenerate (nλ 3 ∼ 280) electron component and with an electron density of about 2.8 × 1023 cm−3.

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.

The low-lying spectra of 8He and 10He nuclei were studied in the 3H(6He, p)8He and 3H(8He, p)10He transfer reactions. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6–3.9 MeV and (1+) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr, respectively. Some evidence for a 8He state at about 7.5 MeV was obtained. We discuss a possible nature of the nearthreshold anomaly above 2.14 MeV in 8He and relate it to the population of a 1− continuum (soft dipole excitation) with a peak value at about 3 MeV. The lowest energy group of events in the 10He spectrum was observed at ∼ 3 MeV with a cross section of ∼ 140 μb/sr. We argue that this result is consistent with the previously reported observation of 10He providing the new 10He g.s. position at about 3 MeV

Samples of stainless steel 12Cr18Ni10Ti with radiogenic helium were subjected to mechanical tests with a constant extension rate. The presence of {sup 3}He does not markedly affect the strength characteristic, but significantly decreases plasticity of steel. The presence of hydrogen enhances the embrittlement of steel, containing {sup 3}He. The diffusion coefficient of hydrogen does not change significantly in the presence of helium, but the traps for hydrogen, which occur due to the presence of helium, delay the kinetics of a steady state flux onset at helium concentration of 50 appm. (authors)

We present some results of studying the influence of high-pressure hydrogen (80 MPa), radiogenic 3He (with concentrations up to 130 appm), and their joint action on the mechanical properties and structure of 12Kh18N10T steel in the temperature range from 293 to 873 K. We describe the procedure of tests of specimens containing 3He. It has been established that the joint action of hydrogen and 3He affects slightly the ultimate strength of the specimens. Saturation of steel with radiogenic 3He by the method of “tritium trick” increases its yield strength. Hardening of the steel caused by helium increases with temperature and 3He concentration and, at 873 K, is accompanied by substantial embrittlement. We also present results of the fractographic analysis of specimens tested under different conditions.

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 paper presents results of tritium-structural materials interaction modeling by simultaneous exposure to radiogenic helium-3 and hydrogen (both dissolved and external). This method of synergetic effect of radiogenic helium-3 and hydrogen is a radiation-safe technique to study the tritium impact on mechanical properties of structural materials. Applicability of the method is illustrated by technique and research results on the impact of high-pressure hydrogen (80MPa), helium-3 (concentration ∼140appm) and their synergetic (hydrogen+ 3 He) effecs on mechanical properties of CrNi40MoCuTiAl alloy in temperature range from 20 to 600°C. It has been shown that joint effect of radiogenic helium-3 and hydrogen on mechanical properties of alloy can not be represented as the result of a simple summation of helium and hydrogen embrittlement. Proposed technique of synergetic impact of radiogenic helium-3 and hydrogen allows more correct simulation and investigation in the tritium impact on mechanical properties of materials than individual research in helium or hydrogen embrittlement.

For the experiment on the measurement of the electron antineutrino magnetic moment we suggest a new approach to the tritium source design, namely, a configuration of annular cells filled with TiT{sub 2} that are stacked into a hollow cylinder. Detectors are mounted in the hole inside.We present results of the optimization of geometrical and physical parameters of the source with respect to its experimental effectiveness and safety guaranty at all stages of its lifecycle. We discuss the choice of the construction materials and specify technological issues relevant to radiation purity of the source, being of the special concern in the experiment on the electron antineutrino magnetic moment measurement.

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 measure muon catalyzed fusion (MC) parameters in liquid tritium with the accuracy better than 10% in the reaction ttμ → 4 He + n +n+ μ, a cryogenic tritium target (CTT) of a 8.1 cm 3 volume was created. The CTT is a radiation-safe complex containing chemically bound tritium in the form of uranium tritide in a special source. In 2003, using the CTT, two runs of measurements with liquid tritium MC parameters were made on the synchrocyclotron muon channel in the Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research (DLNP JINR).

The paper presents designs of a set of high-pressure targets developed by RFNC-VNIIEF and JINR collaboration to study muon-catalyzed fusion at high density of hydrogen isotopes in a wide temperature range. Designs, technical and operating characteristics of the targets and service results are described.In 1997-2002 these targets were used to measure basic characteristics of muon catalysis in pure deuterium, binary D/T mixture and triple H/D/T mixture as a function of density ([variant phi] = 0.2 - 1.2 LHD{sup *}), temperature (T = 20-800 K) and concentration of hydrogen isotopes in a mixture.

Experimental data on the shock compression, temperature, and absorptivity of gaseous deuterium with an initial density close to its value in the liquid state were obtained on a spherical explosion shock-wave generator in a pressure range of 80–90 GPa. The obtained results are compared with the existing experimental and theoretical data.

A cryogenic tritium target and computer-controlled equipment providing for feeding/recovering tritium into/from the target cell and radiation monitoring in technological lines and in workrooms is described. The tritium target set-up showed reliable operation in experiments done with a 58.3 MeV triton beam focused on a 5 mm spot at intensity approaching 3×107 s−1. The t+t elastic scattering cross-section was obtained in a wide angular range.

TheseparatorACCULINNAwasupgradedtoachievenewexperimentalrequirements.Thebeamlinewasextendedbynewion-opticalelementsbeyondthecyclotronhall.Thenewarrangementsyieldmuchbetterbackgroundcondi-tions.Theintensitiesof 6 Heand 8 Heradioactivebeamsproducedinfragmentationof35AMeV 11 Bionswereincreaseduptoafactorof10.Theupgradedbeamlinewasusedinexperimentstostudythe 5 Hresonancestatespopulatedinthet þt reaction.Acryogenicliquidtritiumtargetwasdesignedandinstalledattheseparatorbeamline. 2002ElsevierScienceB.V.Allrightsreserved. PACS:25.70.Mn;29.25.RmKeywords:Radioactive ion beams;Productiontarget;Profileddegrader;Liquidtritiumtarget 1.IntroductionTheseparatorACCULINNA[1]isinoperationsince1996.Highintensityprimarybeamsof 7 Li, 11 B, 13 C, 15 Nand 18 Owithenergyvaluesrangingbetween32and50AMeVaredeliveredbytheU-400Mcyclotrontotheproductiontargetoftheseparator.Thesecondarybeamsof 6 Heand 8 Henucleiwithenergiesofabout25AMeVallowedustogainnewinsightsintothestructureofneutronhalonucleithroughthestudyofone-andtwo-neutrontransferreactionsmadewithhydrogenandheliumtargets[2–5].Suchbeamsofferfavor-ableconditionsfortheproductionofsofarun-knownparticle-unstablenucleibeyondtheneutrondripline.Forthispurposeonecoulduseone-stepone-proton and two-neutron transfer reactionsoccurringwheneither

A design of the deuterium high-pressure target is presented. The target of a 76-cm3 volume is intended to study muon-catalyzed fusion reactions in ultrapure D2 (the concentration of impurities with Z > 1 is under 0.2 ppm) at temperatures of 80–800 K and up to 150-MPa pressures. The operation of the main target systems is described: the generation and purification of deuterium gas, refrigeration, heating, evacuation, control, and automated data acquisition. The target was used to determine the parameters of the muon-catalyzed fusion reactions in ultrapure D2 at temperatures of 300 to 800 K and pressures up to 150 MPa.

This paper describes the system being designed to study the processes of hydrogen isotopes (or their mixtures) interaction with a solid body at pressures up to 500 MPa. Hydrogen isotopes pressure is produced by a thermodesorption source based on vanadium dihydride. Gas is sampled through an intermediate volume. Gas chromatograph is used to analyze the gas for isotopic composition. Possibility of the system development is exemplified by temperature dependencies of equilibrium desorption pressures for vanadium dihydride in a pressure range up to 500 MPa obtained using available equipment.

The design of deuterium high-pressure target of 76 cm3 volume developed to study muon catalyzed fusion in diffusion-pure deuterium over an 80–800 K temperature range at up to 150 MPa pressure is presented.

Experimental study on muon catalyzed dt fusion in a triple mixture of hydrogen isotopes (H/D/T) was carried out at the JINR phasotron. The measurements have been performed at various temperatures and densities with liquid and gaseous H/D/T mixtures. Results are presented for the main characteristics of the dtμ cycle. A reduction of the number of dt fusions is observed when hydrogen is added to the D/T mixture, This is mainly due to muon loss to the pt and pd cycles, which have a high sticking probability. We also observe an increase of the cycle rate when the temperature of the H/D/T mixture rises. This confirms the theoretical prediction.

Experiments on the study of the muon catalyzed fusion (μCF) process in a double D/T mixture of hydrogen isotopes in the temperature range 300–800 K at densities 0.3–0.5 LHD are performed at the JINR phasotron. The values of the effective μCF parameters (cycling rate λ c , neutron yield Y n , muon losses w) are obtained. Tentative dtμ-molecule formation rates on D2 and DT molecules (λ dtμ−d and λ dtμ−t ) are obtained for different mixture temperatures and densities. The results obtained show that λ dtμ−t increases with temperature, but its value is smaller than theoretical predictions.

Muon catalyzed dt fusion in dense D/T and H/D/T gas mixtures of hydrogen isotopes is studied by the MCF collaboration at JINR. The measurements were carried out with a high pressure target at the JINR phasotron in the temperature range 300-800 K at mixture densities \( \simeq 0.4{\text{ and }} \simeq {\text{0}}{\text{.8 LHD}}\). Tentative experimental results obtained by several analysis methods are presented.

A facility is described that allows safe handling of high tritium gas activity as dozens kilocuries in a regular laboratory environment. It is used to make and deliver into the target a mixture of specific isotopic composition with the contamination requirement of 10-7 v.f. for Z>1 elements, and recover it upon completion of operation. With this facility, efforts have been accomplished to investigate into the muon catalyzed fusion on two targets – liquid tritium and high-pressure tritium types. Also, the operation range was 0.1–120 MPa for pressure and 20–800 K for temperature and the amount of tritium used was about 100 kCi. The facility showed reliability in operation without indications of radiation beyond the safety level.

Preliminary data are first presented for the measurements of effective parameters of MCF processes in dense D/T mixtures obtained by a novel method. Results are compared with the ones obtained by the “standard” method.

The low-lying spectrum of 8 He was studied in the 3 H( 6 He, p ) 8 He transfer reaction for small center of mass angles. The 0 + ground state (g.s.) of 8 He and excited states, 2 + at 3.6–3.9 MeV and (1 + ) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μ b/sr. Some evidence for the excited state at about 7.5 MeV can be found in the data. The possible nature of the near-threshold anomaly above 2.14 MeV in 8 He is related to the population of a 1 – continuum (soft dipole excitation) with a peak energy value at about 3 MeV. This assumption can probably resolve the problem of a large uncertainty existing in the experimental data on the 8 He 2 + state energy.

We present results from an investigation into the burning of a gas-free Ti + C system (diluted to 20% with titanium carbide), this system contained in combination with an igniter tablet fabricated out of a Cr2O3 + 2Al + 4B mixture in a rigid shell. We have demonstrated that the burning is accompanied by displacement of the material through the appearance of a decompression wave (a sharp reduction in density in the vicinity of the combustion front), thus leading to a change in the burning velocity.

Low-energy spectra of the He-8,He-10 nuclei were investigated in the (t, p)-type reactions at small centre-of-mass angles using similar to 25AMeV beams of He-6 and He-8 nuclei. The 0(+) ground state (g.s.) of He-8 and excited states, 2(+) at 3.6-3.9MeV and (1(+)) at 5.3-5.5 MeV, were populated with cross-sections of 200, 100-250, and 90-125 mu b/sr, respectively. To account for a near-threshold anomaly observed in the He-8 spectrum the population of a 1(-) continuum (soft dipole excitation) was considered. The lowest-energy group of events in the He-10 spectrum was observed at similar to 3MeV with a cross-section of similar to 140 mu b/sr. This result is consistent with the previously reported observation of He-10 providing a new g.s. position for He-10 at about 3MeV.

The nuclear system {sup 5}H was studied using the {sup 3}H(t,p){sup 5}H transfer reaction at a laboratory energy of 57.7 MeV and small center of mass angles. The energy and angular correlations among the {sup 5}H decay fragments were obtained by complete kinematical reconstruction. A broad structure in the {sup 5}H missing mass spectrum above 2.5 MeV with a typical width of several MeV was identified as a mixture of 3/2{sup +} and 5/2{sup +} states. Analysis of interference patterns observed in the measured angular correlations disclosed the 1/2{sup +} ground state of {sup 5}H concealed in the smooth missing mass spectrum. The deduced values for the resonance energy and width are E{sub g.s.}{approx_equal}1.8 MeV and {gamma}{sub g.s.}{approx_equal}1.3 MeV. The estimated cross sections for population of the ground state and the doublet of excited states at {theta}{sub c.m.}=5 deg. are 150{+-}50 {mu}b/sr and 4.6{+-}2 mb/sr, respectively.

International audience; The $^{5}$H system was produced in the $^{3}$H(t, p) $^{5}$H reaction studied at small CM angles with a 58MeV tritium ion beam. High statistics data were used to reconstruct the energy and angular correlations between the $^{5}$H decay fragments. A broad structure in the $^{5}$H missing-mass spectrum showing up above 2.5MeV was identified as a mixture of the $3/2^+$ and $5/2^+$ states. The data also present an evidence that the $1/2^+$ ground state of $^{5}$H is located at about 2MeV. Then, the $^{5}$H and $^{5}$He systems were explored by means of transfer reactions occurring in the interactions of 132MeV $^{6}$He beam nuclei with deuterium. In the $^{2}$H( $^{6}$He, $^{3}$H) reaction a T = 3/2 isobaric analog state of $^{5}$H in $^{5}$He was observed at an excitation energy of 22.0±0.3MeV with a width of 2.5±0.3MeV.

The 5H system was produced in the 3H(t,p)5H reaction studied with a 58 MeV tritium beam at small c.m. angles. High statistics data were used to reconstruct the energy and angular correlations between the 5H decay fragments. A broad structure in the 5H missing mass spectrum showing up above 2.5 MeV was identified as a mixture of the 3/2+ and 5/2+ states. The data also present evidence that the 1/2+ ground state of 5H is located at about 2 MeV.

Resonance states of 5H were investigated through the two-neutron transfer reaction t(t, p)5 H. A triton beam at 57.5 MeV and a cryogenic liquid tritium target were used. The 5H missing mass spectrum in triple coincidence, proton + triton + neutron, shows a resonance at 1.8 ± 0.1 MeV above the t + 2n decay threshold. This energy is in good agreement with the result reported in Phys. Rev. Lett. 87 (2001) 092501. The resonance width, Γintr ≤ 0.5 MeV, is surprisingly small and difficult to reconcile with theory predictions. © 2003 Published by Elsevier B.V., SCOPUS: ar.j, info:eu-repo/semantics/published

A study is made of the accuracy of approximation of the strength-characteristic distributions of structural materials in the region of low (0.01–0.1) probabilities. Normal, log-normal, Weibull, and Gumbel distributions are examined. It is established that the Weibull distribution law is the most accurate approximation.

An environmentally safe liquid/solid tritium target suitable for beams of radioactive nuclei was created and used in the study of t+d and t+t transfer reactions with putting emphasis on the observation of 4H and 5H resonance states. A state of 4H with Eres=3.22±0.15 MeV and Γobs=3.33±0.25 MeV was obtained in t+d reaction from the spectra of protons leaving the target at θlab=18°–32° and detected in coincidence with tritons. A valuable fraction of protons detected in t+t reaction at θlab=18°–32° in ptn coincidence events was attributed to the states of 5H nucleus. At ∼2.5 MeV above the tnn decay threshold the 5H spectrum shows up a narrow maximum followed by a wide structure at 4–7 MeV. One can not exclude that interference effects could modify the observed 5H resonance maximum resulting in its energy shift and width reduction.

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.