RU2023487C1 - Method for extraction of hydrogen isotopes from hydrogenated titanium - Google Patents

Abstract

FIELD: nuclear power engineering. SUBSTANCE: reactor holding metal titanium is evacuated to 10^-3 Pa and heated to 700 C. Mixture of hydrogen isotopes is fed for 30 minutes. Reactor is cooled down to 200 C, evacuated once more at a rate of 10 deg/min to 670 C and then at the same rate to 700-800 C. Deuterium and hydrogen flows obtained in the process are separated. EFFECT: facilitated procedure. 1 dwg

Description

 The invention relates to methods for the separation of hydrogen isotopes located, for example, in the gas phase, in the gas mixture released during the operation of nuclear reactors, as well as when providing fuel for fusion plants.

A known method of separating isotopes of one chemical element by thermal diffusion [1]. Closest to the invention is a method for extracting hydrogen isotopes [2]. A known method is as follows. A titanium-based alloy is placed in a chamber through which a stream of hydrogen containing heavy isotopes is passed. The temperature of the process is fixed in the range of -20. .. + 40 ^о С, and the pressure of the gas mixture is selected so that it is higher than the hydride dissociation pressure, at least for one of the hydrogen isotopes at a given temperature.

 As a result of saturation carried out under these conditions, the content of hydrogen and its isotopes in the metal increases, and in some cases (for example, in the titanium-chromium alloy), the ratio of the concentrations of heavy and light isotopes in the hydride is higher than in the gas phase. After saturation, the hydride is isolated and thermally decomposed at a fixed temperature. In this case, the separation of various isotopes from the hydrogenated metal occurs simultaneously, and the percentage of heavy and light isotopes in the resulting gas mixture is determined by their content in the hydride.

 The disadvantage of this method is the impossibility of separate extraction of hydrogen isotopes.

The aim of the invention is to provide a method for the separate extraction of hydrogen isotopes from hydrogenated titanium. This is achieved in that the metal titanium, being in a pre-evacuated to 10 ^-3 Pa and heated to 700 ^{° C} the reactor is contacted with a gas mixture of hydrogen isotopes for 30 minutes to form a hydride-deyteridnoy phase, after which the reactor was cooled ^to 200 C, evacuated again and heated at 10 deg / min to 670 ^{° C} and further at the same rate to ^about 700-800 C, the deuterium flow desorbed up to 670 ^{° C,} is isolated from the stream of hydrogen desorbed at ^about 700-800 WITH.

PRI me R. A gaseous mixture of hydrogen isotopes is fed into a pre-evacuated to 10 ^-3 Pa and heated to 800 ^{° C} reactor in which the metallic titanium is an effective scavenger of hydrogen and its isotopes. The supply of the gas mixture is 30 minutes. After closure saturation process, which proceeds at the same temperature very rapidly, the chamber was cooled to 200 ° ^C. As a result of this procedure is obtained hydrido titanium deuteride, stable at temperatures below 400 ^{° C,} the hydrogen content (deuterium) which is close to the stoichiometric composition of TiH ₂ (TiD ₂ ), that is, for each atom of titanium there are approximately two atoms of hydrogen (deuterium).

Upon cooling to 200 ^C. channel overlap Incoming gas mixture, the chamber is evacuated, after which the evacuation system is switched off and the reactor was heated at 10 deg / min.

 As follows from the results of experiments carried out on a TG-DSC 111 installation from CETARAM (France), the separation of hydrogen isotopes from titanium hydride-deuteride in linear heating is separate.

 The drawing shows a graph showing the separation of the flows of hydrogen and deuterium depending on temperature.

At temperatures lower than 670 ^{° C,} is released deuterium and at 700-800 ^C. - hydrogen. Studies have shown that isotope separation is most effective if the heating rate is 10 deg / min. In this case, the peak positions corresponding to the separation of deuterium and hydrogen, are offset relative to each other on the temperature scale of more than 100 ^{° C,} while they themselves are well separated peaks, indicating the high efficiency of the proposed method of separation of hydrogen isotopes.

 The use of high heating rates during gas evolution from the volume leads to blurring of the peaks, their overlap and, as a result, mixing of various flows. At the same time, the use of too low heating rates leads to a decrease in the temperature interval between the peaks corresponding to the evolution of various hydrogen isotopes, which complicates their separation.

 The different binding energy of hydrogen and deuterium with the metal atoms surrounding them leads to a difference in their thermal stability under thermodynamically nonequilibrium conditions of linear heating, which causes the separation of hydrogen and deuterium flows in time.

 Thus, the invention allows for the efficient separation of hydrogen isotopes and selectively pump them into the corresponding storage volumes.

Claims (1)

METHOD FOR REMOVING HYDROGEN ISOTOPES FROM HYDROGEN TITANIUM, including evacuating the reactor with titanium, contacting the latter with a gas mixture of hydrogen isotopes, evacuating the reactor and heating it, characterized in that the reactor is evacuated to a pressure of 10 ^-3 Pa, contacting titanium with a gas mixture of hydrogen isotopes is carried out at 700 ^o C for 30 minutes, after which the reactor was cooled to 200 ^o C, a heating rate of 10 lead dg / min to 670 ^o C and further at the same speed to 700 - 800 ^o C, and obtained by said evap rah respectively flows of hydrogen and deuterium are separated from each other.

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