CS219585B1 - A method of determining a powerless correction for measuring the coolant temperature difference by determining a minimum deviation - Google Patents

Abstract

The essence of the method is that during the hot idle state of a nuclear power reactor, the data of groups of temperature sensors with an outlet line are measured and from them, one sensor with an outlet line with the same or closest data is selected from the hot and cold branches of the circulation loop for the purposes of operational measurement of the temperature difference. The emphasis is placed primarily on the fact that the data of the temperature sensors are measured together with the outlet line directly at the installation site and in conditions that are close to the operational ones in terms of temperatures, pressures and flow rates and that the coolant temperatures in both branches are the same. This eliminates systematic errors in the operational measurement of the temperature difference, according to which the reactor performance is controlled.

Description

The invention relates to a method of determining a power-free correction of the measurement of the coolant temperature difference by determining at least the deviation of the temperature sensors in the hot and cold branches of the core power reactor loop and solves the problem of avoiding systematic errors of this measurement in the power-free state.

On water-water nuclear power reactors, the heat generated by the fuel cartridges through six loop loops is removed to the steam generators. The dissipated power is monitored in each circulation loop by the temperature sensors in the hot and cold branches, which is actually an operational measurement of the coolant temperature difference. Since at full power of the reactor, the coolant temperature difference in the hot and cold branches reaches about 27 ° C, the operator attempts to identify possible systematic deviations and minimize them. This is also done by tuning the operational measurement of the refrigerant temperature difference by determining the minimum deviation of the temperature sensors in the hot and cold branch of the circulating loop during hot-off state when the refrigerant circulating through all six loops is approximately 260 ° C and does not generate any heat. The current method of tuning and the method of determining the resulting deviation were based only on laboratory calibration data of the temperature sensors themselves. This is not correct for thermoelectric cells, given the latest technical literature knowledge for two reasons. The first is that the resulting voltage of the circuit of the thermoelectric cell composed of its own sensor and compensation line consists of the electromotive force (EMS) of the thermoelectric cell and the EMS compensation line. The size of the EMS components depends on the temperature range in which the thermocouple and the compensating line are located. Thus, for example, on the circulation loops of the VVER-440 reactor, the EMS thermocouple produces from 290 ° C (260 ° G) to about 100 ° C, compensating coppering from about 100 ° C to the junction temperature. The second reason stems from the fact that for a real thermoelectric cell, the laboratory calibration results cannot be transferred to the operating conditions due to the fact that the location and size of the temperature gradient during laboratory calibration and operating conditions are consistent. It is also not correct for resistance thermometers and therefore it is required to measure outlet temperature sensors directly on the mixer under operating conditions.

These drawbacks are eliminated by the method of determining a powerless correction of the measurement of the refrigerant temperature difference by determining the minimum deviation of the temperature sensors of the hot and cold branch of the core reactor power loop, which basically means that Outlet temperature sensors on the hot branch and three outlet temperature sensors on the cold branch, the three outlet sensors on each branch are selected one by one from each branch with the same or the closest absolute temperature, the temperature difference of the selected pair the temperature sensors correspond to the minimum deviation of the respective circulation loop and at least the deviation is also a power-free repair of the respective circulation loop.

A new, greater effect is achieved by providing, during a hot-power-free state, temperature sensors with a discharge line under operating conditions, characterized by on-site installation, temperature drop on thermocouples, compensating lines, discharge lines and other influences. The heat-free state is also the default for power modes, so it is important at this moment to tune the zero operational measurement of the coolant temperature difference. For this purpose, the best mode of experiment is to determine the heat loss and heat capacity of the primary circuit, during which six circulation pumps are in operation, the heat is not dissipated from the steam generators, and the temperature in the primary circuit gradually increases. At the same time, the coolant temperatures at the same time in the cold and hot branches are the same or differ only by the value given by the design solution. a specific primary circuit, and remains the same during power modes. Thus, it can be assumed with high probability that outlet temperature temperature sensors are to show zero temperature difference values and if this is not the case, this is due to systematic errors. If, under these conditions, the output voltage of the lead temperature sensors is measured by an analog-to-digital converter, it is possible to select from the hot and cold branch those lead-in sensors whose readings are equal or close and use them for continuous measurement. The data difference, if any, represents the minimum deviation of the operational measurement of the coolant temperature difference in the respective circulation loop.

Specific procedure in the implementation of the method

219 585 to tune the operational measurement of the coolant temperature difference by determining the minimum deviation is as follows: first, the absolute temperature data from the three outlet temperature sensors on the hot branch and three on the cold branch are measured using an analogue to digital converter. Select one of each string with the same or the closest absolute temperature from the three sensors with wiring on each branch. Any difference in data from the analogue-to-digital converter is the minimum deviation of the respective circulation loop.

For example, a loop of holi: measurement results for one sensor no. 1 2 3 cold branch 258.9 ° C 257.4 ° C 258.7 ° C hot branch 258.1 ° C 259.4 ° C 259.0 ° C

Deviations are determined from the combinations of differences of the individual branch data, as follows:

1 - 1: 258.9 - 258.1 = +0.8 ° C

1-2: 258.9-259.4 = -0.5 ° C

1-3: 258.9-259.0 = -0.1 ° C

2 - 1: 257.4-258.1 = -0.7 ° C

2-2: 257.4-259.4 = -2.0 ° C

2 - 3: 257.4-259.0 = -1.6 ° C

3 - 1: 258.7 - 258.1 = +0.6 ° G

3-2: 258.7-259.4 = -0.7 ° C

3-3: 258.7-259.0 = - 0.3 ° C

From the example, it can be seen that the sensor with lead no. 1 from cold branch in pair with no. 3 of the hot branch. The data of the two lead-in sensors will be used subsequently for the operational measurement of the temperature difference, with the correction to the data in the power operation for the considered circulation loop from the power-free mode being –0.1 ° C. The procedure is analogous to all circulation loops. It is recommended that when selecting lead-in sensors, the sum of the minimum deviations of all circulating loops is zero as the technological process is governed by the mean temperature difference of all circulating loops. The proposed method has been tested on Unit 2 of the V-1 Nuclear Power Plant and has saved working time in tuning the operational temperature difference measurement system and has helped to detect systematic system errors.

The mentioned method of tuning the temperature difference by determining the minimum deviation can be used also on other technological objects, where it is necessary to measure exactly the temperature difference of the coolant at certain temperature levels by temperature sensors. This method can be used to tune the measurement of the coolant temperature difference by means of resistance thermometers, where the temperature difference is calculated from the absolute values of the temperature in the hot, and the cold branch of the circulating loop or thermoelectric cells in differential connection.

Claims (1)

1 219 585 tuning the operational measurement of the coolant difference by determining the minimum deviation is as follows: first, the temperature data of the absolute temperatures at the output of the three-temperature sensors with the hot line and the three on the cold line are measured with the analog-digital converter. with guidance on individual branches, select one of each branch with the same or the nearest absolute temperature. Any difference in data from the analog-to-digital converter is the minimum deviation of the respective circulating loop. For example, holi: measurement results for one sensor No. 1 2 3 cold branch 258.9 ° C 257.4 ° C 258.7 ° C hot branch 258.1 ° C 259.4 ° C 259.0 ° CZ combinations of individual differences the branch data are determined as follows: 1—1: 258.9 - 258.1 = +0.8 ° C 1–2: 258.9 - 259.4 = —0.5 ° C 1 - 3: 258.9 - 259.0 = - 0.1 ° C 2 - 1: 257.4 - 258.1 = —0.7 ° C 2—2: 257.4 - 259.4 = —2 , 0 ° C 2 - 3: 257.4 - 259.0 = -1.6 ° C 3 - 1: 258.7 - 258.1 = +0.6 ° G 3-2: 258.7 - 259, 4 = —0.7 ° C 3–3: 258.7 - 259.0 = —0.3 ° EN example, it can be seen that the minimum deviation has a sensor with lead no. 3 from the hotflower. The data of these two outgoing line sensors will be used for the subsequent measurement of the temperature difference, in that the correction to the power operation data at the recirculated loop of the non-power mode is ,10.1 ° C. All circulating loops are analyzed analogously. In the selection of outgoing line sensors, it is recommended that the sum of the minimum deviations of all circulating loops be zero since the technological process is controlled by the average temperature difference of all circulating loop stages. The proposed method was tested by the second block of the V-1a nuclear power plant, which meant saving the working time of adjusting the operating temperature difference measurement system and helping to detect systematic system errors. The aforementioned method of tuning the temperature difference by means of determining the minimum deviation may also be applied to other technological objects, where it is necessary to measure the refrigerant temperature difference at certain temperature levels by the sensing temperatures. This method can be used to tune the measurement of the coolant temperature difference with the aid of resistance thermometers in which the difference in temperature is calculated from the absolute temperature values of the hot and cold branches of the circulating loop or thermoelectric cells in the differential circuit. SUBJECT A method of determining the powerless correction of the measurement of the coolant temperature difference by determining minimally the deviation of the heat-aging and cold-branch sensors circulating in the loop-core energy reactor, characterized in that they are measured by analog-numbering during a hot, non-equilibrium mode. by the converter the absolute temperature output data from the three temperature sensors with the hot-line outlet line and the temperature sensors with the outlet in the cold branch, from the three sensors with the output line on the individual branches, select one of the same or the nearest absolute temperatures The difference in temperature of this selected pair of temperature sensors corresponds to the minimum deviation of the respective circulation loop and the minimum deviation is also a no-fault correction of the respective circulating loop.