JPS5890138A - Leak monitoring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a reactor containment vessel for a nuclear couplant that houses structures that use high-temperature, high-pressure fluid. This invention relates to a leak monitoring device for monitoring leaks from, etc.

TECHNICAL BACKGROUND OF THE INVENTION The prior art will be explained by taking an atomic couplant as an example. In nuclear couplants, a reactor containment vessel is provided to house the reactor and secondary cooling system, etc., and to prevent nuclear fission products from leaking to the outside. Because of the high temperatures, air conditioners are generally used to cool the area to a set temperature.

Leak monitoring devices from primary coolant equipment, piping, etc. that are conventionally used in reactor containment vessels are not used for cooling inside the containment vessel because operators cannot access the reactor containment vessel during plant operation. A cooling water inlet temperature detector and a cooling water outlet temperature detector are installed in the cooling water supply and return pipes connecting the cooling coil and refrigerator of the air conditioner, respectively, and the detected temperatures are monitored. During continuous rated operation, if the difference between the outlet temperature and inlet temperature of the cooling water that cools the air conditioner exceeds a set level, a warning is issued as a leak of high-temperature coolant.

Problems with the Background Art Conventional leakage monitoring devices detect leakage of high-temperature coolant based on the difference in temperature between the entrance and exit of the cooling water to the air conditioner.
Since the influence of fluctuations in the cooling water supply flow rate is not taken into account, in reality, the temperature difference level that triggers the alarm must be set relatively high, resulting in poor sensitivity and a relatively large amount of leakage. For the first time, an alarm was issued and the operator was notified. Therefore, it is unsuitable for early detection of a failure in which a small leak of high-temperature fluid gradually expands and eventually breaks. In addition, leakage monitoring based on the difference in temperature between the entrance and exit of cooling water to an air conditioner involves monitoring the entire heat load within the relevant area relative to the air conditioner, and includes monitoring internal structures such as the reactor pressure vessel and primary cooling system. Since it is not possible to separate the heat load due to steady heat dissipation from the heat load due to leakage from the heat load due to steady heat dissipation from It was extremely difficult to monitor them separately.

Purpose of the Invention The present invention has been made in order to improve the above-mentioned problems. To quickly detect leakage of high-temperature fluid from piping, etc., even if it is a small amount, by accurately distinguishing the increased heat load due to the leak from the existing heat load due to steady heat radiation1. It is an object of the present invention to provide a leakage monitoring device capable of monitoring.

Summary of the Invention A cooling water system that supplies cooling water from a refrigerator to a cooling coil of an air conditioner that conditions the inside of a containment vessel that houses a structure that uses high-temperature fluid to a constant temperature. A cooling water flow rate detector and a cooling water inlet temperature detector are installed in the supply pipe, and a cooling water outlet temperature detector is installed in the cooling water return pipe, and the measurement output signals of these detectors are exchanged to the heat amount calculator. Calculate the amount of heat exchanged by the air conditioner by
At the same time, the average value of the amount of heat exchanged is calculated, and the average value is corrected at regular intervals and stored in the storage device, and the air conditioner is replaced by the amount of exchanged heat calculated by the amount of exchanged heat calculation unit while the reactor continues to operate at its rated value. The amount of heat is monitored in the form of a difference from the average value stored in the storage device, and if there is a difference greater than a set level between the value obtained by the exchange heat amount calculator and the average value, it is The system is designed to issue an alarm indicating that high-temperature fluid is leaking from the structure.

Embodiment of the Invention An embodiment of the leak monitoring device (5) according to the present invention will be described with reference to FIG. Figure #c1 is a configuration diagram when the leak monitoring device according to the present invention is used in a boiling water reactor containment vessel.

Inside the reactor containment vessel 1 is a reactor pressure vessel 2. A part of the water supply pipe 3 that supplies high-temperature and high-pressure coolant to the reactor pressure vessel 2, a part of the main steam pipe 4 that sends out the generated steam, and reactor-subsystem equipment such as the reactor recirculation equipment 5. Since the inside of the reactor containment vessel 1 becomes high in temperature due to heat radiation from each of these facilities, an air conditioner 6 is provided in the containment vessel 1 to cool the inside to a constant temperature.

Cooling water is supplied to the cooling coil 7 of the air conditioner 6 from a refrigerator 8 installed outside the reactor containment vessel 1, and the air cooled by the cooling coil 7 is circulated by a fan 9 to reduce the temperature inside the containment vessel l. is kept constant. In order to determine the amount of heat exchanged by the air conditioner that cools the inside of the reactor containment vessel 1, a cooling water flow rate detector 11 is installed in the cooling water supply pipe 10 that supplies cooling water from the refrigerator 8 to the cooling coil 7. A cooling water inlet temperature detector 12 is attached, and a cooling water outlet temperature detector 14 is attached to the cooling water return pipe 13 through which the cooling water returns from the cooling coil 7 (6) to the refrigerator 8. The cooling water flow 1
゛The output signals of the detector 11, the cooling water inlet temperature detector 12, and the cooling water outlet temperature detector 14 are led to an exchange heat amount calculator 15 that calculates the exchange heat amount of the air conditioner 6 and the average value of the exchange heat amount. A storage bag #t16 for storing the average value of the exchanged heat amount is attached to the exchanged heat amount calculator 15. Furthermore, a comparison circuit 17 is connected to the exchanged heat amount calculator 15, which continuously compares the calculated value by the calculator 15 and the average value of the exchanged heat amount stored in the memory bag [16]. An alarm device 18 is attached that issues an alarm when the comparison value exceeds a certain level.

Generally, heat radiation from each structure in the reactor containment vessel 1 increases monotonically from the time the reactor is started until the rated operating state is reached, and becomes a substantially constant value in the rated operating state. Therefore, the amount of heat exchanged by the air conditioner gradually increases during the start-up period T1, as shown by the curve in Figure 2, where the horizontal axis is the operating time T of the reactor and the vertical axis is the amount of heat exchanged by the air conditioner Q. However, during the rated operation period T2, it becomes almost constant, and this value is the amount of heat exchanged with respect to the heat load due to heat radiation from the internal structure.

The cooling coil 7 of the air conditioner 6 (assuming that the flow rate of the cooling water supplied is V, and the temperatures of the cooling water passing through the inlet and outlet of the cooling coil 7 are Hl and H2, respectively, the amount of heat exchanged in the air conditioner 6 Q= V (H2-H1), therefore, the cooling water flow rate V is determined by the flow rate detector 11, the cooling water inlet temperature H1 is determined by the inlet temperature detector 12, and the cooling water outlet temperature H2 is determined by the outlet temperature detector 14.
Measure ζ and exchange those measured values with the heat amount calculator 1
5, the momentary exchange heat amount Q of the air conditioner t6 can be calculated from the above equation l. At the same time, the average value of the amount of heat exchanged during each certain period of time is calculated, and the value is transferred to and stored in the storage device f16.

As long as there is no leakage of high-temperature coolant from each device, piping, etc. in the reactor containment vessel 1 and normal rated operation continues, the air conditioner 6 only needs to cool down the heat load due to heat radiation. The amount of exchanged heat Q remains almost constant and is almost equal to the average value stored in the storage device 16, the output of the comparison circuit 17 is almost at zero level, and the alarm 18 is not driven. However, if leakage of the high-temperature coolant occurs during continued rated operation, the heat load within the containment vessel 1 will increase, so the exchange heat amount calculation value calculated by the exchange heat amount calculation unit 15i will increase. As shown in FIG. 2, at the time when the leakage occurs, the exchanged heat value becomes greater than or equal to the average exchanged heat amount corresponding to the heat radiation number, and the comparator circuit 17 immediately and accurately distinguishes it from heat radiation and sensitively captures this increase. The alarm 18 is activated to issue an alarm to notify of leakage of high temperature coolant.

Effects of the Invention As described in detail in the embodiments, the leak monitoring device according to the present invention is suitable for use in containment vessels that house structures that use high-temperature fluids, such as nuclear reactor containment vessels. Continuously monitor the amount of heat exchanged by the air conditioning equipment that cools the area in which it is stored, comparing it with the average value of the amount of heat exchanged, and detect leakage of high-temperature fluid from the structure by detecting the amount of heat exchanged with each leak. By comparing the increase in heat radiation from the structure with the average value, the system detects the heat radiation from the structure and issues an alarm (9), so it can detect leakage of high-temperature fluid from the structure early and with high sensitivity. Moreover, there is an effect that the detection can be accurately distinguished from heat radiation.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram when a leak monitoring device according to an embodiment of the present invention is used in a boiling water reactor containment vessel, and Fig. 2 shows the amount of heat exchanged by the air conditioner for cooling the reactor containment vessel and the reactor operating time. FIG. ■... Reactor containment vessel, 6... Air conditioner, 7...
Cooling coil, 8... Refrigerator, 10... Cooling water supply pipe line, 11... Cooling water flow rate detector, 12... Cooling water inlet temperature detector, 13... Cooling water return pipe line , 14...
Cooling water outlet temperature detector, 15... Calculator for exchange heat, 1
6...Storage device, 17...Comparison circuit, 18...Alarm device. (7317) Agent Patent attorney Kensuke Norichika (and 1 other person) (10)

Claims (2)

[Claims] (1) Store equipment, piping, etc. that use high-temperature fluids,
A leak monitoring device that monitors leakage of high-temperature fluid in an area cooled by an air conditioner, comprising a cooling water flow rate detector and a cooling water inlet temperature detector provided in a cooling water supply pipe that cools the air conditioner; The amount of heat exchanged by the air conditioner is determined from the measured values of the cooling water outlet temperature detector provided in the cooling water return pipe, the cooling water flow rate detector, the cooling water inlet temperature detector, and the cooling water outlet temperature detector. and a monitoring alarm device that continuously monitors the exchanged heat amount calculated by the exchanged heat amount calculator and issues an alarm when the exchanged heat amount increases beyond a set level as necessary. A leak monitoring device featuring: (2) The exchanged heat amount calculator is provided with a function to calculate the exchanged heat amount and the average value of the exchanged heat amount, and the exchanged heat amount calculated by the exchanged heat amount calculator is continuously compared with the average value of the exchanged heat amount. 2. The leakage monitoring device according to claim 1, further comprising a comparison alarm that issues an alarm when the increase in the amount of exchanged heat from the average value exceeds a set level.