Installation for determination of hydrogen in uranium dioxide fuel pellets

FIELD: the invention refers to analytical chemistry particular to determination of general hydrogen in uranium dioxide pellets.

SUBSTANCE: the installation has an electrode furnace with feeding assembly , an afterburner, a reaction tube with calcium carbide, an absorption vessel with Ilovay's reagent for absorption of acetylene, a supply unit. The afterburner of hydrogen oxidizes hydrogen to water which together with the water exuding from pellets starts reaction with carbide calcium. In result of this equivalent amount of acetylene is produced. The acetylene passing through the absorption vessel generates with Ilovay's reagent copper acietilenid which gives red color to absorption solution. According to intensity of color of absorption solution the contents of general hydrogen are determined.

EFFECT: simplifies construction of the installation, increases sensitivity and precision of determination of the contents of hydrogen in uranium dioxide pellets.

2 cl, 1 dwg

 

The invention relates to analytical chemistry, in particular the determination of total hydrogen pellets of uranium dioxide by the method of melting in an inert gas, recommended S (Standard methods for chemical, mass spectrometric and spectroscopic analyses of powders and pellets of uranium dioxide nuclear grade. AC/ATM S-80, cniiatominform, Moscow, 1982, translation No. 129 p-147, str-185).

In this way the tablet of uranium dioxide is heated to a temperature greater than 1800°C. the hydrogen gas Evolved previously held the chromatographic purification from nitrogen and carbon dioxide, measured by integration of the peak output from a heat conductivity detector.

The main disadvantage of this method is the use of complex, expensive equipment and bulky chemical cleaning of gases.

The closest to the technical essence of the prototype is way analysis of hydrogen in the fuel tablets patent No. 2151434, MKI G 21 17/06, G 01 N 27/14, 2000 According to this method, the analyzed tablets placed in the evaporator, heat up and released the water and the hydrogen gas flow of the carrier are transferred to the hydrogen recombiner to the water in the copper oxide, after which the flow of carrier gas containing only water vapor, enters the coulometric sensor, where the water is absorbed and the same hour is decomposed by electrolysis into hydrogen and to slort. Spent on electrolysis of water the amount of electricity, which is a measure of humidity is recorded by the integrator current.

The main disadvantage of this method is the complexity of the equipment and the need to apply coulometric sensors, requiring frequent cleaning from the dust of the analyzed products and change of hygroscopic substances. In addition, the error in the determination of hydrogen is about 50% in the determination of hydrogen in the range of 1·10-5-1·10-4%.

The objective of the invention is to simplify the design of the facility, improving sensitivity and accuracy of determination of hydrogen content in the pellets of uranium dioxide.

This task is solved by the fact that the device for determination of hydrogen pellets of uranium dioxide containing electrode furnace with the charging device, hydrogen recombiner, the loop pipe, power supply, according to the formula of the invention, the installation is equipped with a tube with calcium carbide and consistently connected with her adsorption vessel with reagent Ilova, the input tube is connected to the output of the hydrogen recombiner and the bypass pipe.

This set of features is new and involves an inventive step, so as to measure the total hydrogen used method of using calcium carbide, which, coming into R. the action of water, highlights acetylene. Further, when the bubbling acetylene through the reagent Ilova produced acetylene copper, the color of which is changed even if the change is negligibly small fluctuations acetylenic copper reagent Ilova.

The use of this reaction allows to increase the sensitivity of the determination of total hydrogen pellets of uranium dioxide on the order of (≈3·10-5%). In addition, the installation allows to determine not only hydrogen, but also the water in a wide range of water concentrations in solid materials, such as carbon dioxide and nitrous oxide of uranium.

The drawing shows a block diagram of the setup for the determination of total hydrogen in tablets.

Installing a hydrogen electrode consists of a furnace (1), hydrogen recombiner (2), the bypass pipe (3)that is installed parallel to the backburner of hydrogen, the reaction tube with calcium carbide (4), the absorption vessel with reagent Ilova to absorb acetylene (5), power unit (6).

The power supply is a power transformer with an output voltage up to 15 V withstand current load up to 450 and ensuring the smooth heat of tablets in the evaporator from 100 to 1800°C.

The scale of measurement standards is a series of tubes with a mixture of nitric acid cobalt and nitric acid chromium in proportions corresponding to a water content of 1 cm3

Installation to determine the total hydrogen pellets of uranium dioxide works as follows. In the furnace download a sample of 6 tablets and heated to 1800°C. the Liberated hydrogen and water flow are carried away by the inert gas in the hydrogen recombiner (2) to the water, where the hydrogen on the copper oxide is oxidized to water, and the resulting water together with water released from the sample, the flow of carrier gas is entrapped in the reaction tube with calcium carbide (4), where the reaction of water with calcium carbide produces acetylene. Next acetylene in the same gas stream is transported to the absorption vessel (5) and barbatiruem through the reagent Ilova. In the reaction of acetylene and the reagent Ilova formed painted in red acetylene copper. This reaction is very sensitive, allowing the intensity of the received color to set the content of total hydrogen production by photometric measurements on photocalorimetry, using the calibration curve for standard calibration solutions of nitric acid cobalt and nitric acid chromium.

To determine the moisture content of solid materials released water vapor from the investigated samples, the bypass pipe bypassing the hydrogen recombiner, served in the reaction tube with calcium carbide. For this purpose made scale standards, providing the definition of the odes in the range of hundredths to one or two percent.

Device for determination of hydrogen in the fuel pellets of uranium dioxide containing electrode furnace with the charging device, hydrogen recombiner, the loop pipe, a supply unit, characterized in that the installation is equipped with a tube with calcium carbide and consistently connected with her adsorption vessel with reagent Ilova, the input tube is connected to the output of the hydrogen recombiner and the bypass pipe.



 

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SUBSTANCE: the installation has an electrode furnace with feeding assembly , an afterburner, a reaction tube with calcium carbide, an absorption vessel with Ilovay's reagent for absorption of acetylene, a supply unit. The afterburner of hydrogen oxidizes hydrogen to water which together with the water exuding from pellets starts reaction with carbide calcium. In result of this equivalent amount of acetylene is produced. The acetylene passing through the absorption vessel generates with Ilovay's reagent copper acietilenid which gives red color to absorption solution. According to intensity of color of absorption solution the contents of general hydrogen are determined.

EFFECT: simplifies construction of the installation, increases sensitivity and precision of determination of the contents of hydrogen in uranium dioxide pellets.

2 cl, 1 dwg

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