SU1227037A1 - Method of obtaining protective coating for metal surfaces - Google Patents

Abstract

1. THE METHOD OF OBTAINING A PROTECTIVE COATING FOR METAL SURFACES, including applying a layer of material on the surface of equipment that comes in contact with the medium containing hydrogen isotopes, in order to increase the effective suppression of the diffusion flow of hydrogen isotopes, On the surface of the substrate, these are the ternyls, which oxidize hydrogen isotopes, to heat the surface to the oxidation temperature of hydrogen isotopes to water and maintain this temperature during the service life. equipment .c:

Description

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Tempervgurv with.

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2. The method according to claim 1, about tln ch yusch and with the fact that, with the aim of improving the environment, on

the surface is coated with copper oxide, the surface is heated up to 200 ° C and is held for a lifetime.

one .

The invention relates to the energy, chemical industry and other areas of the national economy, where cymecTJByWT is designed to prevent the diffusion of hydrogen isotopes through the metal surfaces of the equipment. The purpose of the invention is to increase the effect of suppressing the diffusion improvement of radiation in the vicinity of

In this case, materials oxidizing hydrogen isotopes are applied to the surface of the equipment, heating the coating to a temperature of 1 ° C oxidation of hydrogen isotopes to water and maintaining this temperature during the service life;

To improve radii1.1: ionic conditions when working with tritium in reactor conditions and the surface is applied; OXIDE of copper, and heating and vyderzhku carried out at the temperature of oxidation of tritium to water in the range of 200-400 ° C.

When diffused through. metaplastic surface isotopes of hydrogen, interacting with the material, are acidified with water to the reaction (for example, the coating is copper oxide, the hydrogen isotope-tritium) S

C + TgO

CHi-t- T,

the temperature at which the reactions take place is different, for copper, 1 example, 200-DOOs. The water resulting from this reaction does not penetrate through the coating. The temperature range is selected from the following considerations. At C, the rate of oxidation of hydrogen isotopes is very low, and at t 400 ° C, there is a probability of dissociation of copper oxide (see Fig. 1),

When choosing a material for coating, various media were investigated. In tab. 1 shows the process rates, the activation energy and the order of the reaction during the oxidation of the indicated hydrogen compounds at T and the hydrogen concentration

in the gas phase 1 vol.%. The table shows that the most suitable as a coating. are oxides of copper, cobalt, nickel, manganese, chromium.

Figure 1 shows the oxidation of hydrogen as a function of the temperature of copper oxide; figure 2 - installation. on the study of the diffusion of hydrogen; Fig. 3 installation for the study of maneuvering nuclear power reactor.

The installation includes a cylinder 1 with helium 5 valves 2, 3, 4, 5, ampoule 6 with a layer of substance oxidizing hydrogen Ti3OTonb, flow autoclave 7, thermogram 8, cylinder 9 with hydrogen, sample pressure gauge 10, hydrogen analyzer 1. A fuel assembly 12 with nuclear fuel in an active zone. 0 reactor, stainless steel coil 13, charged with a neutron absorber by helium, system 14 created by helium pressure and vacuum vacuuming in the coil 13, water test carrier 15 of the nuclear reactor, cooling heat-generating assembly and coil,.

The helium from cylinder 1 through valve 2 and 3 fills ampoule 6 and flow through valve 7, which are placed in thermostat 8. Valve 3 closes. Valve 5 opens and from cylinder 9 a certain amount of hydrogen is added to ampule 6. The amount of hydrogen in ampule 6 is measured Bbw specimen with pressure gauge 10. Flow of gels from cylinder 1 through valve 2, autoclave 7, valve 4 is fed to an EYSE-sensitive sense. The analyzer 11 is hydrated 10 yes. The sensitivity of the analyzer is 0.02 vpm (2 ..%).

During operation of the facilities in the heat assembly, 12 neutrons are generated. When neutron 45 is absorbed by helium coming from system 14, a hydrogen isotope, Tritium, is formed in coil 13, which diffuses at the operating temperature of Mayevik 1 3 320-350s1 through the coil walls the water coolant 15. This increases the radioactivity of the water carrier 15. Offered The method proceeds with the following. A layer of a material capable of oxidizing hydrogen isotopes to water is applied on the surface of the equipment in contact with the hydrogen isotope. The material most appropriate in its chemical characteristics for reaction with hydrogen isotopes is selected from the table. In the case of reactor installations (see Fig. 3), in order to suppress the diffusion of hydrogen-tritium isotopes, an important condition for choosing a coating material is the absence of radioactive isotopes; therefore, cobalt, manganese, chromium oxides are not suitable for these purposes, since they form long-lived CO isotopes. After applying a layer of material during operation of the equipment when heated, a diffusion of hydrogen isotopes begins through the surface. When thermotechnical oxidation of hydrogen isotopes is reached, they begin to interact with the oxide of the coating by the MeO + reaction. N. HjO + Me. The oxidation temperatures for CuO-200400 0, Cr and above are low and correspond to the operating temperatures. These temperatures must be maintained throughout the life of the equipment. As an example, studies were carried out on the installation for the study of hydrogen diffusion (see Fig.2) and on the installation for studying the nuclear reactor power maneuvering (see Fig. 3). Thus, the installation (see Fig. 2) with hydrogen diffusion through the austenitic steel OH18H10T with an ampoule thickness of 1 mm and a diameter of 10 mm yielded the following results: Consumption of helium 5 .10 bodies 10 kPa Pressure helium Installed concentrations of hydrogen in helium Т 873К .10ЧПа Сн, 300vpm Т 823 ° К. Cis 235 vpm (3.tO vol.%) (I, 35.10 vol.%). 37 "Calculated. According to the experimental results, the values of the parameters of hydrogen permeability Kp 5.2. 4 (0.1 MPa) - hydrogen permeability coefficient; Qq 77.3 kJ / mol, hail - activation energy of the process of hydrogen and hydrogen diffusion fluxes of hydrogen (873 ° K 10 kPa) 0.252 M mch (823 K, 10 kPa) 0.197, which in the previously adopted system of units corresponds to K 0.032 cm, cm cmC (barG; Qa 18460 cal / mol.grad. Diffusion coefficients 3.61., (T 823k); 3.80. (T) Comparison of diffusible hydrogen fluxes through ampules from ОХ18К10Т steel, ampoules from the same steel with deposited on 30 microns of copper oxide and an ampoule filled with bimetal by chemical method; extra-layer OX18H10T layer steel — internal copper that is oxidized to at a temperature of 300 ° C for 1 h are presented in Table 2. From Table 2 it can be seen that the diffusion of hydrogen is completely suppressed compared to an uncoated ampoule and with a ceramic coating in copper-coated ampoules. fig. 3) on the study of power maneuvering with periodic cleaning of gels on the cleaning system as a result of tritium diffusion through the walls of the coil 13 (length 40 m, and diametr .. 6 mm) cooling water coolant activity which is 1.5 m a week of operation increased by 3 of about (10 times). This creates an unfavorable situation in the maintenance and quality control of the water coolant. It was then appropriate to apply copper oxide coatings on the inner surface of the coil. The coating was applied as follows: 1. The internal surface of the coil was degreased - washed with acetone and then with alcohol. 2. It was washed with distilled water from alcohol residues 3, At a temperature of 8b-90 ° C, a solution of copper sulphate (300 g / l) and sulphate (20 g / l) is pumped through the coil to create a thin, dense layer of copper. 4, The copper layer is increased by chemical copper to 20-30 microns. 5. The coil is removed by distilled water from chemical reagent copper plating. 6. Air is pumped through the coil and the coil is gently heated for 1 hour to a temperature of 300 ° C. As a result, the copper oxidizes to copper oxide. During the operation of the facility, the activity of the heat transfer medium 15 is measured. The experiment showed that there is no diffusion of tritium, since the level of activity of the water heat carrier through this radionuclide (tritium) does not increase, which is caused by the oxidation of tritium to vapors by the reaction CuO + T, Cu + TjO Water formed from tritium does not penetrate stainless steel. K 6.0., 3.10. 5.2.10 ZH 10. I1112 0.4 0.5 0.60.5

Table 1, 2.2., 3, A, 6.10 3.0.0 7.0.1o 1.5.1o 3, 9. , 0. 9.5.10 The regeneration of copper oxide can be carried out by blowing air or oxygen at t 300-350 ° C. From these examples it can be seen that it is possible to increase the effectiveness of suppressing the diffusion of hydrogen isotopes through the surface of the equipment. Thus, in an installation with forced gas cleaning from tritium (see Fig. 3) 9 diffusing through the metal shell without coating, it is impossible to completely exclude the release of tritium into the coolant. This is evidenced by an increase in the radioactivity of the coolant. After the deposition of copper oxide on the metal surface, the tritium yoliostio code ceases, as indicated by a constant level of radioactivity. Compared to the release of hydrogen through the surface of equipment with a glass ceramics layer applied, a layer of material that oxidizes hydrogen isotopes to water eliminates the diffusion flow of hydrogen altogether and thereby eliminates hydrogen embrittlement problems of about 1.5.o 4.8.10 9, A.1o 171514, in 0,70,50,7

Mg.

Fe

Mn K 5.8.10 4.0.10 1.5. E E 15 15 16 n 0.6 0.5 0.5

Cd

Mg K E n K E n Ampoule made of steel. ОХ18Н10Т h

ten

Ampoule with cover-.

em.so sso. ,

Bimetal ampoule

Ampoule with ceramic coating

Continuation of table

Chromite Co Ni

Zn

Si

Ferrite

Co ni

Zn

Cu

-9

1.7.10

623

623

Missing

623

Missing

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2.8.10

623 2,4.ld 2,5., 5.lo 6,2.0 1, 4. lo 5.2 lo 9.6.10 20 J718 -} 5 17 16 16 0.0 0.70 0.7 0.6 0.6 0.7 0.7 .4.4 reaction rate, expressed in molecules of oxidized hydrogen per cmVc. -.V. . : activation energy / mol. . , until the dock is resolved. I, 8.1o4,2.t0 2,8.io 1,7.0 15 14 13 19 0,5 -p, 5 0,8 0,6 T a l and c: a 2

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