JPS58216774A - Control method for heat transfer system connecting nuclear equipment and seawater desalination equipment - Google Patents

Abstract

PURPOSE:To prevent the leakage of harmful material components such as radioactivity in the stage of transferring heat from a heat generation system to a heat utilization system, by monitoring the pressure of an intermediate heat medium in the heat transfer part in the mid-way thereof in such a way that said pressure is kept always higher than the steam bleeding pressure of a turbine in the heat generation system. CONSTITUTION:If the standard value of the extraction steam S to be bled from a steam bleeding part 1a of a nuclear power installation is defined as 14kg/cm<2>ab, prescribed horse power is beforehand given to a circulation pump 18 in order to assure 16kg/cm<2> ab which is higher than said value in the intermediate heat medium (k) to be circulated in a piping system 4 for the heat medium in an intermediate indirect heat exchanger 3. A differential pressure indicating controller 16 is beforehand so set that an output is produced therefrom when th differential pressure DELTApc is at the value except the value in a 2kg/cm<2>ab< DELTAPC4kg/cm<2>ab. The pressure of the extraction steam pressure and the pressure of the intermediate heat medium are inputted respectively through pressure detectors 14, 15 to the controller 16. A flow rate control valve 17 is throttled in accordance with the detected output thereof, whereby the pressure within the differential pressure range is maintained.

Description

[Detailed Description of the Invention] This relates to a coupling plant that utilizes the heat generated by water as a heat source for a seawater desalination system, and in particular uses an intermediate heat medium to connect a nuclear power equipment steam extraction section and a seawater desalination system to prevent radioactivity leakage. The present invention relates to a method of controlling a heat transfer thread.

Chronic shortage of water supply resources to meet water demand Since it is thought that the demand for water will clearly exceed the available water resources in the future, desalination of seawater is being planned and Development is also progressing. An example of such a device is a seawater desalination device that uses the heat generated in a nuclear power plant.The heat transfer system that transfers the heat generated by a nuclear power plant to the seawater desalination device is shown in Figure 1. It is configured. The heat generated in the nuclear power generation turbine 1, for example, 1 4 kgj/m ab (here ab
(means absolute pressure), the heat of the turbine bleed air S is transferred to a piping system 2, an intermediate indirect heat exchanger 3, e.g. 1 6 kin ab
1 piping system 4, a flash tank 5, a heating medium h1 piping system 6 of 1,5 k-ab, and a brine heater 7 of the seawater desalination equipment, for example 2 klij.
/ m ab is transmitted to seawater 0. In such a configuration, high pressure (16 kg/m ab
) is refluxing, so even if the heat exchanger tubes and heat exchanger tube attachments are damaged in the intermediate indirect heat exchanger 3, radioactively contaminated steam of 14 kld ab will not enter the piping system. Therefore, there is no leakage from the reactor side to the seawater desalination equipment side. However, even if the heat medium k flowing through the piping system 4 is set to a higher pressure than the turbine bleed air S as described above, the load on the nuclear power generation turbine 1 often fluctuates greatly and the turbine bleed air S also fluctuates accordingly. There are cases where the turbine bleed air S pressure exceeds the pressure of the heat medium. In such a case, the operator has to throttle the bleed air amount control valve 8, which is installed in the piping system 2, each time, which is unbearable.

For this reason, there is a long-awaited development of a control method for a heat transfer system that can effectively and easily perform a leakage prevention function from a nuclear reactor to a seawater desalination apparatus.

The purpose of the present invention is to monitor the intermediate heat medium pressure in the heat transfer section during heat transfer from the heat generation system to the heat utilization system so that it is always higher than the turbine extraction pressure of the heat generation system, thereby reducing radioactivity. An object of the present invention is to provide a method for controlling heat transfer connecting a nuclear power facility and a seawater desalination device, which can effectively prevent the leakage of harmful substance components.

According to the present invention, the purpose is to constantly detect the differential pressure between the turbine extraction pressure on the reactor side and the intermediate heat medium pressure on the seawater desalination equipment side, and to calculate the intermediate heat medium pressure based on this differential pressure detection output. This is achieved by controlling the pressure to be higher than the turbine extraction pressure.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 2, a nuclear equipment steam extraction section (for example, a nuclear power plant turpin extraction section) 1a is coupled via a heat transfer system A to a brine heater 7 of a seawater desalination apparatus 9. The heat transfer system A includes a piping system 2 of the steam extraction section 1a, an intermediate indirect heat exchanger 3 to which an outer tube 3a is connected, and a circulating heat exchanger connected to an inner tube 3b of the intermediate cylinder indirect heat exchanger 3. It consists of a medium piping system 4, a flash tank 5 connected to the piping system 4 for evaporating a high temperature intermediate heat medium to generate steam, and a circulating steam piping system 6 connected to the flash tank 5.

The brine heater 7 connected to the circulation steam piping system 6 has a seawater piping system 1 through which seawater to be introduced into the seawater desalination device 9 flows back.
0 is concatenated.

The outlet of this seawater piping system 10 and the steam piping system 6
A temperature control system 11 is disposed between the inlet of the brine heater 7 and the inlet of the brine heater 7 in order to correct load fluctuations.

Pressure detectors 14 and 15 are connected to the upstream side of the piping system 2 of the vapor extraction section 1a and the outlet side of the intermediate indirect heat exchanger 3 of the heat medium piping system 4, respectively.

The outputs of the pressure detectors 14 and 15 are the common differential pressure indicating controller 1.
6, and its output is connected to the control input of a flow rate control valve 17 provided on the outlet side of the intermediate indirect heat exchanger 3 of the heat medium piping system 4.

Note that 18 in FIG. 2 is a circulation pump, and in this embodiment, a constant horsepower is given to it. Further, 8 is a bleed air amount control valve, 1
9 is a condensate pump for the brine heater.

The operation of the heat transport system of the present invention constructed as described above will be explained below.

If the standard value of the extracted steam S extracted from the nuclear equipment steam extraction section 1a is 14 kg/m ab, the intermediate heat medium k flowing back through the heat medium piping system 4 in the intermediate indirect heat exchanger 3 has a higher pressure than that. It is assumed that a predetermined horsepower is given to the circulation pump 18 in order to ensure 161s'd ab. Moreover, the differential pressure Δpc is 2k1m a in the differential pressure indicating controller 16.
b<ΔPC<4k! It is assumed that the setting is made in advance so that the output is output when the value is outside the range of 9/d. Therefore, the steam is extracted from the steam extraction section 1a at a rate of 14 ky/d.
Let us consider the case where the extraction steam pressure of ab increases due to load fluctuations of the nuclear turbine 1. The pressure of the extracted vapor pressure is measured by a pressure detector 14, and its output is measured by a differential pressure indicating controller 1.
Enter 6. On the other hand, the pressure (16 kgn ab ) of the intermediate heat medium flowing through the circulating heat medium piping system 4 is also input to the differential pressure indicating controller 16 via the pressure detector 15 . Therefore, the differential pressure indicating controller 16 detects the differential pressure between the intermediate heat medium pressure and the extracted steam pressure as ΔPC<2 kg/cr/l, and the flow rate control valve 17 is throttled based on this detected output. This throttling increased the load on the circulation pump 18, raising the pressure of the intermediate heat medium flowing through the heat medium piping system 4 from the circulation pump 18 via the intermediate indirect heat exchanger 3 to the flow rate control valve 17. The differential pressure is controlled to be within a set range that is higher than the extraction steam pressure. This time, conversely, the extraction vapor pressure is the intermediate heat medium pressure (16
1 2 kNcn, which is the differential pressure limit value between
Regarding the case where the pressure drops below ab, the differential pressure indicating controller 16 detects the differential pressure as Δpc > 6 k-ab, so the flow rate control valve 17 is opened to reduce the load on the circulation pump 18, and the reduced extracted steam is The intermediate heat medium pressure is controlled to fall within a predetermined range. In addition, since the circulating heat medium piping system 4 is connected to the flash tank 5 that follows the load fluctuation of the seawater desalination equipment 9, it is natural that the intermediate heat medium pressure is
Although it is not possible to keep it at 61s/d ab,
Even in such a case, the differential pressure indicating controller 16 detects the differential pressure rather than the absolute value, so control is performed effectively even with fluctuating intermediate heat medium pressure, and the extracted steam pressure is always maintained. keep it higher than.

With this method of controlling the heat transfer system, even if a failure occurs in the intermediate indirect heat exchanger 3, radioactively contaminated steam will not enter the circulating heat medium piping system 4. There is no leakage to the converter side.

In addition, in the above embodiment, the lower limit of the differential pressure Δpc of the differential pressure indicating controller 16 is set not only to zero, that is, when the intermediate heat medium pressure and the extracted steam pressure are equal, but also to a somewhat higher limit (2 k- in the embodiment). The upper limit was set in consideration of safety, and the upper limit was set to prevent the intermediate heat medium pressure from becoming abnormally high due to cumulative throttling of the flow rate control valve 17. The upper limit value and lower limit value can be arbitrarily determined by design.

Further, in the above embodiment, the output of the differential pressure indicating controller 16 is applied to the flow rate control valve 17, but the output is not limited to this, and the output may be applied to the circulation pump 18 to control the pump pressure.

In this case, when the intermediate heat medium pressure is lower than the extracted steam or gas, the horsepower is increased, and when it is higher, the horsepower is decreased.

In summary, according to the present invention, the following effects can be obtained.

(1) The differential pressure between the extracted steam pressure and the intermediate heat medium pressure is detected, and this detection controls the intermediate heat medium pressure to be higher than the extracted steam pressure. Even if both of these factors fluctuate at the same time, it is possible to prevent harmful substance components such as radioactivity from leaking from the nuclear equipment side to the heat transfer system, and safe operation can always be ensured.

(2) It consists of two processes: detection of differential pressure and pressure increase based on this detection, and since detection of differential pressure is performed simultaneously, pressure balance can be established in a short time.

[Brief explanation of drawings]

Figure 1 is a diagram showing the configuration of a conventional heat transfer system control method;
The figure shows the configuration of a preferred embodiment of the method for controlling a heat transfer system according to the present invention. In the figure, 1a is a nuclear equipment steam extraction part, 3 is an intermediate indirect heat exchanger, 9 is a seawater desalination equipment 1, 14, 15 is a pressure detector, 16 is a differential pressure indicating controller, 17 is a flow rate control valve, 18 is a circulation pump, S is extracted steam, k is an intermediate heat medium, and A is a heat transfer system.

Claims (1)

[Claims] An intermediate indirect heat exchanger is provided between the nuclear equipment steam extraction section and the seawater desalination equipment, and the distance between the indirect heat exchanger and the seawater desalination equipment is
In the heat transfer thread that connects J through the intermediate heat medium, the differential pressure between the extracted steam pressure and the heat medium outlet pressure of the intermediate rEI + indirect heat exchanger is detected, and based on this detection output, the heat medium pressure changes to the extracted steam pressure. A method for controlling a heat transfer system connecting a nuclear facility and a seawater desalination device, characterized by controlling the heat medium pressure so that it becomes higher.