JPH037275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reactor water level and recirculation flow rate measuring device for a pressure tube nuclear reactor.

FIG. 1 shows a system diagram of a reactor water level measuring device and a recirculation flow rate measuring device of a conventional pressure tube reactor. Under normal conditions, reactor coolant flows from the steam drum 3 to the downcomer pipe 8 and the recirculation flow rate measuring device. It passes through the manifold 4, is pressurized by the recirculation pump 5, and is sent to the pressure pipe 2 in the reactor 1 via the water drum 7 and the inlet pipe 11. The coolant supplied to the pressure pipe 2 is heated by the nuclear reaction heat of the fuel assembly 10, becomes a two-layer flow (a mixed flow of water and steam), returns to the steam drum 3 via the outlet pipe 12, and is mixed with water. Separated into steam. Furthermore, the steam is sent to the turbine system 15 via the main steam pipe 13. Further, the water separated in the steam drum 3 is mixed with water supplied from the water supply pipe 14 and then recycled to the pressure pipe 2. Note that the downcomer pipe 8 is provided with a throttle mechanism 24 that restricts the flow of coolant in the event of pipe breakage.

In the cooling system of such a pressure tube reactor, the reactor water level measuring device connects the piping 9 and the reference piping 1 to the gas phase part of the steam drum 3 via the leveling device 16.
9, a reactor water level gauge 22 whose one end communicates with the manifold 4 and whose other end communicates with the reference pipe 19, and the downcomer pipe 8.
The reactor water level calculator 18 corrects flow rate pressure loss and coolant density.

On the other hand, the recirculation flow rate measuring device is the recirculation pump 5
The recirculation flowmeter 20 is connected to a flowmeter throttle mechanism 6 provided on the coolant outlet side of the flowmeter and a flowmeter detection pipe 23.

The water level in the steam drum is measured by a steam drum water level gauge 21 disposed between the liquid phase portion of the steam drum 3 and the reference pipe 9.

However, the conventional measuring device configured in this manner requires two measuring devices, a reactor water level measuring device and a recirculation flow rate measuring device, resulting in a problem of system complexity.

This invention was made in view of the above circumstances, and by changing the connection of the measurement piping, a recirculation flow rate measurement function can be added to a conventional reactor water level measurement device. Therefore, the throttling mechanism type recirculation flowmeter can be removed,
Moreover, it is an object of the present invention to provide a reactor water level/recirculation flow rate measuring device that can simplify the system and rationalize the equipment.

Corresponding to this purpose, the reactor water level and
The recirculation flow rate measuring device is used in a pressure tube nuclear reactor having at least a closed loop that sequentially returns to the pressure tube via a pressure tube, a steam drum, a manifold, a recirculation pump, and a water drum, one end of which connects the A reactor water level flow meter that communicates with the manifold and whose other end communicates with a steam drum pressure gauge and a liquid phase portion of the steam drum via piping, and inputs signals from the steam drum pressure gauge and the reactor water level flow meter. a flowmeter density correction calculator that outputs the recirculation flow rate; and a reactor water level calculator that inputs the signals from the steam drum pressure gauge and the reactor water level flowmeter and the output of the flowmeter density correction calculator and outputs the reactor water level. It is characterized by having a container.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment.

In FIG. 2, 30 is a reactor water level flow meter. The reactor water level flow meter 30 is connected at one end to the manifold 4 via a pipe 31 and at the other end to the steam drum pressure gauge 17 and the liquid phase portion of the steam drum 3 via a pipe 32. What must be noted here is that whereas the conventional detector (i.e., the reactor water level gauge 22) communicates with the gas phase portion of the steam drum 3 via the piping 9 and the reference piping 19, the present invention The detector (namely, the reactor water level flowmeter 30) in is connected to the liquid phase portion of the steam drum 3 via a pipe 32. In this way, by changing the connection piping on one side of the differential pressure detection position of the conventional reactor water level gauge from the steam drum gas phase part to the steam drum liquid phase part, accurate control between the steam drum 3 and the manifold 4 can be achieved. Differential pressure can be measured, and therefore, the conventional reactor water level gauge 22 can be used as a reactor water level flow meter 30 having two functions: reactor water level measurement and recirculation flow rate measurement.

Next, a case will be described in which the reactor water level and recirculation flow rate are determined using the signals from the reactor water level flow meter 30 and the steam drum pressure gauge 17.

In the figure, numeral 33 is a flow rate density correction calculator, and numeral 35 is a reactor water level calculator. The signal from the reactor water level flow meter 30 has an error in the differential pressure corresponding to the position head with respect to the recirculation flow rate. 33 to determine the recirculation flow rate.

In addition, to correct the pressure loss of the downcomer pipe 8 at the reactor water level, the input to the reactor water level calculator is combined with the signals from the steam drum pressure gauge and the reactor water level flowmeter 30, as well as the output of the flowmeter density correction calculator 33. This is done by inputting the information.

In the conventional reactor water level measurement device, a pressure difference occurs between the steam drum 3 and the manifold 4 due to the recirculation flow rate, but since the pressure difference is obtained from the steam drum gas phase, the steam drum water level It is susceptible to fluctuations and has the problem of being inaccurate when determining the recirculation flow rate.

In the reactor water level/recirculation flow measuring device of the present invention configured as described above, the connecting pipe on one side of the differential pressure detection position of the reactor water level flowmeter is connected to the steam drum liquid phase part. , it is possible to obtain a differential pressure due to the recirculation flow rate that is not affected by water level fluctuations in the steam drum, making it possible to accurately measure the recirculation flow rate and eliminating the need for a recirculation flowmeter equipped with a throttle mechanism. Moreover, since the reactor water level can be measured using the signal from the same detector, the system can be simplified and the equipment can be rationalized.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a conventional reactor water level measuring device and recirculation flow rate measuring device of a pressure tube type nuclear reactor, and FIG.
It is a system diagram of a recirculation measuring device. 3... Steam drum, 4... Manifold, 8...
Downcomer pipe, 17... Steam drum pressure gauge, 30... Reactor water level flow meter, 31, 32... Piping, 33...
Flow meter density correction calculator, 35... Reactor water level calculator.

Claims (1)

[Claims] 1 In a pressure tube reactor having at least a closed loop returning to said pressure tube via a pressure tube, a steam drum, a manifold, a recirculation pump and a water drum in sequence, one end communicates with said manifold via piping and the other A reactor water level flow meter whose one end communicates with a steam drum pressure gauge and the liquid phase portion of the steam drum via piping, inputs signals from the steam drum pressure gauge and the reactor water level flow meter, and outputs a recirculation flow rate. a reactor water level calculator that inputs the signals of the steam drum pressure gauge and the reactor water level flowmeter as well as the output of the flowmeter density correction calculator and outputs the reactor water level. A reactor water level/recirculation flow rate measuring device characterized by: