SU701363A1 - Method of checking apparatus for monitoring impurity content in sodium - Google Patents

Abstract

A METHOD FOR CHECKING DEVICE CONTROL DEVICES IN SODIUM CONCENTRATION, including the introduction of impurities into the sodium circuit, determining the increment of impurity concentration by the response of the device, characterized in that, in order to improve the cost-effectiveness of testing, sodium is removed into an additional circuit, and the determination of the increment of impurity concentration is carried out additional circuit with the parameters corresponding to the ratio QNaJjr GNage where qwa is the consumption of sodium through the verification control device; d is the testing time; GNa is the mass of sodium in the main circuit. <1.Is Retention refers to methods of checking devices for controlling the concentration of impurities in sodium circuits of installations with fast neutron reactors or experimental sodium circuits, and can be used, for example, to check the parameters of indicators of water leaks in sodium in sodium-to-water generators. devices (calibrations, performance, performance) under conditions of operation in industrial plants or in experimental plants with large amounts of sodium There is a number of difficulties. A method is known for checking devices controlling various parameters in nuclear reactors and steam generators, which means that the devices are periodically dismantled and checked on a special stand. The disadvantages of this method are: -the need for a special stand; -the impossibility of checking the impurity control devices directly in the working circuit. • There is a known method for checking the concentration of impurities in sodium, including input This sodium circuit and determine the increment of the concentration of impurities by the response of the device. The disadvantage of this method is to increase the cost-effectiveness of the test. The purpose of the invention is to increase the cost-effectiveness of the test. The stated goal is that sodium is added to the additional circuit, and the definition of the impurity concentration is t in the additional circuit with parameters that correspond to the ratio of OSA &gt; &amp; OSL) &gt; &amp;

Description

QNa GNa where QNa is the sodium consumption through the inspection control device; t-time validation; GNa is the mass of sodium in the main circuit. The invention is illustrated in the drawing, which shows a test pattern. Sodium from the main pipeline of the circuit (1) through the additional circuit 2 through the regulating valve 3 (or the flow rate booster) and the flow meter 4 enters the sensor of the impurity concentration monitoring device 5 with the mass flow rate qwa and returns to the main pipeline of the circuit 1. Before the sensor of the monitoring device 5 an impurity metering unit 6 is installed with a flow meter 7 and a shut-off valve 8. When checking the parameters of the monitoring device, the valve 8 of the impurity metering valve b is opened. The generated increment of the impurity concentration D Spr at the input to the sensor of the control device B is defined as the ratio of the mass flow rate of the impurity qnp to the mass flow rate of sodium qwa: ACnp qnp / qNa and is recorded by the recording device of the control unit 9. Subsequent changes in the concentration increment of the metered impurity are produced by changing the sodium flow rate qwa or impurity consumption qnp. The speed of inspections of control devices is achieved by the fact that the creation of the necessary increments in the concentration of impurities is carried out faster than when dosing into the total mass of sodium. In this method, the required time is determined by the time to reach and measure the established mass flows of impurities and sodium consumption, and the transition to other incremental values can be accomplished by simply changing the sodium or impurity flow rates. In the case of dosing to the total weight of sodium, time is required for dosing and achieving a steady state for each increment of concentration. A decrease in the total contamination of sodium by impurities is due to the fact that the mass consumption of sodium through the impurity control device (qNa) is small and the mass of sodium in circuit (G) is large. The time required for checks (g) is also short. Therefore, when industrial and large sodium circuits can be met the condition-p-1. If, for example, an increment in the impurity concentration (ACi) was created to test the device, then during the test the concentration in the common circuit (D C2). will be D Ca-D Ci -I; -, i.e. D C2 D Ci. The effect of loss of metered impurities on the generated increments in the concentrations of impurities is practically eliminated, due to the location of the dispenser in the sodium stream flowing through the sensor of the monitoring device and the dispenser is located close to the sensor. The losses in the common circuit do not affect the created increment of the impurity concentration, and in the plot of the metering device the loss sensor is neglected or an equilibrium between the dissolved impurities in sodium and the construction material is established. Due to the small mass fluxes of sodium through the control devices with the proposed method, it is possible to use impurity dispensers at low rates of impurity dosing. For example, dispensers with pro-membrane membranes can be used easily, having the advantages of intensifying the solution of the impurity in sodium and obtaining a homogeneous stirred solution. If such dispensers were used to dispense into the total mass of sodium, in large sodium circuits, membranes with large surfaces would be required or the dispensing time would be unacceptable for testing control devices. Testing the performance of impurity control devices can be carried out by abruptly changing the impurity concentration during a time substantially shorter than the constant time of the device. This can be achieved by a stepwise change in the sodium or metered impurity consumption. When dosing impurities in the p6aieM circuit, it is not possible to achieve a clear jump in the concentration of impurities due to non-ideal mixing in the circuit. The proposed method for checking the parameters of the device controlling the concentration of impurities was tested on an experimental sodium test bench with a sodium volume of 0.08 m with the emission of the parameters of a hydrogen indicator in sodium IVA-1. The hydrogen sensor in the indicator is a nickel diffusion membrane, the external surface of which is washed by sodium from the circuit, and the internal surface is continuously evacuated by a magnetic discharge pump. Indicator calibration characteristic

represents the relationship between the pump current and the concentration of hydrogen and sodium.

To check the parameters of the proposed method, a dispenser was inserted into the hydrogen sensor of the IVA-1 indicator, consisting of a nickel membrane 0.25 mm thick with a diffusion surface of 400 cm, connected by pipeline through a shut-off valve with a tank for hydrogen of known volume, equipped with an exemplary manometer.

At a sodium temperature in the dispenser of 500 ° C, a flow of hydrogen to sodium of 0.03-0.09 g / h was ensured, depending on the hydrogen pressure in the tank of 50-500 kPa. The flow of hydrogen was calculated from the measurement over time of the pressure drop in a tank of a known volume. The consumption of sodium through the indicator varied within 100, .. 1000 kg / h and measured with a magnetic indicator flow meter. The range of generated increments of the concentration of hydrogen in sodium was 0.03-0.9 (3.10 -9.10 wt.%) At that, which is enough for testing the indicator in its operating range. After hydrogen is supplied to the dispenser cavity, the equilibrium hydrogen flow (99%) was established in less than 30 seconds and in the sodium stream at the entrance to the hydrogen sensor, the concentration increase was established in accordance with the ratio of Asn and Calib QNa

The results of the method under consideration were compared with calibrations by the method of inputting into the total mass of sodium and, taking into account measurement errors, a coincidence was obtained.

Tests were also carried out on the industrial installation BN-350. The results show good compliance with the calibra- tion. Vominal characteristics obtained in laboratory conditions when dispensing into the total mass of sodium and under industrial conditions when dispensing hydrogen into the sodium stream flowing through the indicator. The possibility of a quick check of the parameters of the indicator at a negligible level of sodium contamination in the general sodium circuit of the industrial plant was confirmed. The time required for calibration (5 points) does not exceed 1 hour.

The use of this method of checking the parameters of steam generator leak indicators can provide an economic effect by increasing the resource of sodium cleaning agents from impurities and reducing the non-operating time of steam generators by significantly reducing the time for checking the parameters of indicators.

Claims (1)

METHOD FOR CHECKING DEVICES FOR CONTROL OF CONCENTRATION OF IMPURITIES IN SODIUM, including the introduction of impurities into