JPS62293192A - Decay heat removing 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] 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention relates to a decay heat removal device using a sodium-heated steam generator in a fast breeder reactor plant. In particular, it relates to improvements in once-through steam generator systems.

(Prior Art) Generally, in fast breeder reactor plants, it is customary to provide a decay heat removal device for removing core decay heat after the reactor is shut down. There are various types and system configurations of this decay heat removal device, and one type uses a steam generator.

There are various system configurations around the steam generator, and typical ones are shown in FIGS. 2 and 3.

Figure 2 shows a recirculating steam generator system.
Thermal energy generated in the reactor 1 is sent to the intermediate heat exchanger 3 by the secondary cooling system main circulation pump 2, and is further transmitted to the superheater 5 and the evaporator 6 via the secondary cooling system main circulation pump 4. .

On the other hand, on the steam side, the steam is heated in the evaporator 6 and flows into the steam drum in a two-phase flow state, where saturated steam and saturated water are separated. The saturated water is mixed with the feed water from the high pressure feed water heater 8 and returned to the evaporator 6 again by the recirculation pump 9. The saturated steam is sent to the superheater 5, turned into high-temperature superheated steam, and sent to the steam turbine 10, which drives the generator 11.

The steam after working in the steam turbine 10 is transferred to the condenser 12.
This condensate is sent to a deaerator 15 via a condensate pump 13 and a low-pressure feed water heater 14,
Further, the water is sent to the high-pressure feed water heater 8 as feed water via the feed water pump 16 .

Figure 3 shows a once-through steam generator system, in which the thermal energy generated in the reactor 1 is sent via an intermediate heat exchanger 3 to an integrated once-through steam generator 17, where the water side and heat be exchanged. On the steam side, water from the high-pressure feed water heater 8 is directly supplied to the steam generator 17, becomes superheated steam at the outlet of the steam generator 5, and is sent directly to the steam turbine 10 as it is.

(Problems to be Solved by the Invention) In the conventional recirculating wet steam generator system, even if the recirculating pump 9 is stopped after the reactor 1 is stopped, the steam drum 7 and the evaporator 6 are Heat removal in a stable state is possible due to natural circulation between the two. Moreover, the advantage in this case is that the final settling temperature becomes the saturation temperature of the steam drum pressure, which reduces the temperature drop from the operating temperature, which reduces thermal shock to the equipment and ensures structural integrity. This can be cited as being advantageous. On the other hand, the disadvantage is that it requires a steam drum 7 and a recirculation pump 9, and due to thermal balance conditions, the required heat transfer area is larger than that of a once-through steam generator 17, which will be described later. Both of these conditions are economically disadvantageous.

On the other hand, the integrated mass flow steam generator system is economically advantageous because the equipment is simpler and the required heat transfer area is smaller than that of the recirculating wet steam generator system. However, for stable operation of the steam generator 17, there is a limit on the lower limit of the water side outlet, and this limit is generally much larger than the flow rate required during decay heat removal operation, so that the recirculated moisture It does not provide the operational advantages of steam generator systems.

The present invention has been made in consideration of these points, and provides a decay heat removal device that can operate stably during decay heat removal operation while maintaining the economic efficiency that is an advantage of a once-through steam generator. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a once-through steam generator system that includes a steam separator connected to the outlet side of the steam generator, and a saturated water separated by the steam separator. The present invention is characterized in that it is equipped with a jet pump that extracts water from the high-pressure feed water heater and supplies it to the integrated once-through steam generator.

(Function) In the decay heat removal device according to the present invention, during the decay heat removal operation, the saturated water separated by the steam-water separator flows through the jet pump using the water supplied from the high-pressure feed water heater as the driving fluid. type steam generator. Therefore, recirculation operation is possible with a simple structure, and when the reactor is shut down, it is possible to shut down the reactor at a high temperature in a stable operating state, and thermal shock to the reactor etc. can be alleviated.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a nuclear reactor, and the thermal energy generated in this reactor 1 is sent to an intermediate heat exchanger 3 by a secondary cooling system main circulation bomb 2, and then a secondary cooling system main circulation pump 4. The water is transmitted to the integral once-through steam generator 17 via the steam generator 17.

This integral flow type steam generator 17 exchanges heat with the water side.

On the other hand, on the steam side, water from the high-pressure feedwater heater 8 is directly supplied to the integral once-through steam generator 17 via the main water supply control valve 18 and the steam generator inlet water supply stop valve 19. Superheated steam sent from the integral flow type steam generator 17 is directly sent to the steam turbine 10 via a steam pipe 21 having a steam generator outlet stop valve 20. After doing work in the steam turbine 10, the steam is sent to a condenser 12 to become condensate, and this condensate is sent to a deaerator 15 via a condensate pump 13 and a low-pressure feed water heater 14. Further, the water is sent to the high-pressure feed water heater 8 as water via the water feed pump 16.

The steam generator outlet stop valve of the steam piping 21 is located on the 20 person side.
As shown in FIG. 1, a steam separator 24 is connected via a branch pipe 23 having a steam separator stop valve 22.
The saturated water separated by the steam separator 24 is transferred to the check valve 25.
The water is sent to the suction side of the jet pump 27 via a piping 26 having a
It is now sent to

The jet pump 27 is installed to bypass the steam generator inlet water supply stop valve 19 as shown in FIG.
Saturated water is extracted from 4 and supplied to an integral flow steam generator 17.

The steam/water separator 24 also includes a pipe 31 for recovering a part of the saturated steam separated by the steam/water separator 24 to the deaerator 15 via the deaerator heating control valve 3o, as shown in FIG. , and excess steam is passed to the condenser 12 via the steam separator pressure control valve 32.
A pipe 33 is provided for discharging the water to the respective pipes.

Next, the operation of this embodiment will be explained.

During normal operation, feed water from the high-pressure feed water heater 8 is directly supplied to the integral flow steam generator 17 via the steam generator inlet water stop valve 19, and becomes superheated steam at the outlet of the steam generator 17. and is supplied to the steam turbine 10 as is.

On the other hand, during the decay heat removal operation after the reactor 1 is shut down, the steam separator inlet stop valve 22 is opened and the steam generator outlet stop valve 20 is closed. Thereby, the steam at the outlet of the steam generator 17 is guided to the steam-water separator 24 and separated into saturated water and saturated steam.

A part of the separated steam is recovered to the deaerator 15 via the deaerator heating control valve 30, and the rest is separated into water and water so that the internal pressure of the steam separator 24 becomes the set pressure. The water is discharged to the condenser 12 and regulated by the pressure control valve 32.

On the other hand, on the water supply side, the steam generator inlet water supply stop valve 19
is closed, and water is supplied to the steam generator 17 by the jet pump 2.
Switch to the drive water inlet side of 7. As a result, the saturated water separated by the steam-water separator 24 is extracted by the jet pump 27, mixed with feed water, and supplied to the steam generator 17. As a result, during decay heat removal operation, heat removal operation can be performed using a recirculation method.

〔Effect of the invention〕

As explained above, in a once-through steam generator system, the present invention includes a steam separator connected to the outlet side of the steam generator, and saturated water separated by the steam water separator from a high-pressure feed water heater. Since a jet pump is installed to extract water from the feed water and supply it to the integral flow type steam generator, it maintains the economic efficiency that is the advantage of a once-through type steam generator, while ensuring stable operation during decay heat removal operation. This makes it possible to improve reliability and economic efficiency.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a system diagram showing a conventional decay heat removal device employing a recirculating steam generator system, and Fig. 3 is a once-through steam generator system. FIG. DESCRIPTION OF SYMBOLS 1... Nuclear reactor, 3... Intermediate heat exchanger, 10... Steam turbine, 17... Integral flow steam generator, 19...
...Steam generator inlet water supply stop valve, 24...Steam water separator,
27...Jet pump. Applicant's agent Mr. Sato Figure 1

Claims (1)

[Scope of Claims] 1. Thermal energy generated in the nuclear reactor is transferred to the integrated once-through steam generator via an intermediate heat exchanger for heat exchange, and the superheat generated in the integrated once-through steam generator is In a once-through steam generator system that sends steam directly to a steam turbine and supplies water from a high-pressure feedwater heater directly to the integrated once-through steam generator, the steam generator is connected to the outlet side of the steam generator. A decay heat system characterized by comprising: a separator; and a jet pump that extracts the saturated water separated by the steam water separator using the water supplied from the high-pressure feed water heater and supplies the extracted water to the integrated once-through steam generator. removal device. 2. The decay heat removal device according to claim 1, wherein the jet pump is installed to bypass a water stop valve at the inlet of the integrated once-through steam generator.