The method of dissolving a structural material for fusion reactor based on vanadium - chromium - titanium alloy

 

(57) Abstract:

The invention relates to technology radiochemical processing of structural materials of a fusion reactor. The method consists in the fact that the vanadium - chromium - titanium alloy is dissolved in nitric acid at a concentration of 6-8 mol/l and a temperature of 60-80oC. the Method can solve the problem of dissolution of the alloy in optimal conditions, providing maximum concentration of metals in solution - 50-60 g/L.

The invention relates to technology radiochemical processing of structural materials of a fusion reactor based on vanadium-chromium-titanium alloy.

It is assumed that most affected the activation of the front wall and the divertor of a fusion reactor type "Demo" will consist of vanadium-chromium-titanium alloy (HCT-alloy) approximate composition: vanadium - 90%, chromium - 5% ti - 5%.

After operation of the reactor will need refabricate structural materials, primarily expensive vanadium. This refabricate requires preliminary radiochemical purification of the alloy from radioactive product activation.

For the implementation of clean alloy traditionally the ptx2">

Data about the process of dissolution HCT-alloy in the literature are missing.

It is known from the literature (for example: a chemist's Handbook/ edited by B. P. Nicholas, T. 2, M-L., 1963) that the vanadium soluble in nitric acid, in chrome it does not dissolve, and titanium practically insoluble without additives hydrofluoric acid.

It follows from the above that the present invention has no close analogues.

The objective of the invention is not only to develop ways of dissolution of the alloy, but also ensuring the highest possible concentration of the components of the alloy in the solution, i.e., obtaining a solution in a minimum amount, because the increased volume of processed solutions leads to lower economic efficiency of the process. This is due to increasing consumption of reagents and the main thing - to increase the volume of liquid waste.

In addition, the proposed dissolution must take place within a few hours.

The problem is solved by a method of dissolving a structural material for fusion reactor based on vanadium-chromium-titanium alloy in nitric acid with a concentration of 6-8 mol/l and at a temperature of 60-80oC.

Prov is rastvoreniya. At acid concentrations below 6 mol/l is sharply reduced the dissolution rate and therefore increases the duration of the process.

The dissolution of the alloy in nitric acid with a concentration above 8 mol/l leads to increased consumption of acid, because the higher the concentration of nitric acid, the higher the specific discharge per unit mass of metal. In addition, the solubility of the metals may be reduced when the concentration of acid in solution.

Temperature of the process must be in the range of 60-80oC. lower limit of temperature range provides the desired speed of the process, but most importantly allows you to receive the maximum concentration of the components of the alloy in the solution, providing complete dissolution. The concentrations of the alloy components in the solution are at level 55-60 g/L. the temperature Exceeds 80oWith the achievement of total metal concentrations of 20 g/l leads to the formation of insoluble deposits of metal oxides.

The technical result consists in obtaining the solution components HCT-alloy to a minimum.

This method is illustrated by examples.

Example 1.

Sample alloy composition of 90% V, 5% Ti, ralsa 12 PM Total concentration of metals in solution was 25.4 g/l

Example 2.

A sample of the alloy of the same composition by weight of 2.58 g was dissolved in 100 ml of 6 mol/l nitric acid at 60oC. the Sample was completely dissolved in 5 hours total concentration of metals in the solution amounted to 25.8 g/l

Example 3.

A sample of the alloy of the same composition by weight 3.04 from g was dissolved in 100 ml of 6 mol/l nitric acid at a temperature of ~ 100oC. Fell sludge brown.

Example 4.

A sample of the alloy of the same composition by weight 2,77 g was dissolved in 50 ml of 6 mol/l nitric acid at 60oC. the Sample was completely dissolved in 10 hours total concentration of metals in the solution amounted to $ 55.4 g/L.

Example 5.

A sample of the alloy of the same composition by weight 2,47 g was dissolved in 50 ml of 6 mol/l nitric acid at 85oC. Fell sludge brown.

Example 6.

A sample of the alloy of the same composition by weight of 2.4 g was dissolved in 50 ml of 8 mol/l nitric acid at 85oC. Fell sludge brown.

As seen from the above examples, the dissolution HCT alloy in nitric acid with a concentration of 4 mol/l (example 1) significantly reduces the rate of dissolution compared to restoranivaguni precipitation at total metal concentrations more than 20 g/L. At lower concentrations of the metals in solution are obtained reproducible results.

The data suggests that the claimed method of dissolution HCT-alloy to ensure complete dissolution to obtain the total concentration of metals at the level of 55 g/l (example 4) in a few hours.

The method of dissolving a structural material for fusion reactor based on vanadium-chromium-titanium alloy, which consists in the fact that the dissolution is carried out in nitric acid with a concentration of 6-8 mol/l at a temperature of 60-80oC.

 

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