JPS59195199A - Steam generating system for fast breeder reactor - 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 The present invention relates to a steam generation system for a fast breeder reactor.

Figure 1 shows the steam generation system of a conventional fast breeder reactor. When operating the steam generator in a once-through system in a sodium-cooled fast breeder reactor plant, normal startup/shutdown operations are performed using the startup bypass system ( A system that sequentially passes through a steam generator, a steam separator inlet steam stop valve 16, a steam separator 4, a flash tank 5, and a condenser 9) and a turbine bypass system (steam generator 3, steam separator 4, Steam-water separator outlet steam stop valve 17
, the turbine bypass valve 14 and the condenser 9).

Furthermore, even if the plant trips, unless there is an accident, it is a preferable method in terms of the operating cycle to remove the residual heat in the reactor using the steam system.

On the other hand, in a sodium-cooled fast breeder reactor power plant, liquid sodium is used as a coolant for both the reactor system and the secondary cooling system, which is an intermediate cooling system.
5. In order to prevent the sodium temperature from exceeding 170°C during operation, consideration must be given to the sodium temperature being approximately 170°C or higher. (In fact, the temperature of the water supplied to the steam generator 3 is approximately 140℃ in the operating state where sodium to lithium is contained in the steam generator to prevent local assimilation of athosium.
It is necessary to hold it above 'C'.

Therefore, in the conventional system, after a plant trip, the startup bypass system (steam generator 3, steam
6. Steam water separator 4, flash tank 5, feed water heater (
By operating the feed water heater (low pressure) 19, which sequentially passes through the condenser 9, the feed water to the deaerator 6 is heated.
At the same time, by listening to the main steam drain valve 18, main steam is introduced into the deaerator 6 to prevent pressure drop and maintain the temperature of the stored water in the water storage tank 7 at approximately 150°C, and the water supply pump 12 is turned on. Water is supplied to the steam generator 3 by a pump action.

However, in such conventional systems, relatively low-temperature feed water is introduced into the steam generator 3, so the temperature of the coolant sodium in the reactor 1 rapidly decreases due to the good heat exchange performance in the steam generator. However, there was a problem in that a large thermal shock load was applied to the reactor system and secondary cooling system structures, causing the structural membrane h4 to deteriorate.

This invention has been made in view of the above-mentioned circumstances, and is intended to prevent bleed air from the turbine 8 to the feedwater heaters 11 and 13 from being lost when the turbine trip is prevented or when the plant is operated independently. Even if the water temperature in the water storage tank 7 drops significantly due to a significant decrease in the amount of water supplied, the water will not be supplied to the steam generator at a low temperature.
We propose a steam generation system for a fast breeder reactor that can suppress the thermal shock load on the reactor system and secondary cooling system MPi structure.
The purpose is to

Corresponding to this purpose, the steam generation system of the fast breeder reactor of the present invention at least sequentially includes a steam generator, a steam separator,
In a steam generation system for a fast breeder reactor having a closed loop returning to the steam generator via a turbine, a condenser, a deaerator, and a water storage tank, an additional feed water heater is provided in the steam generator inlet piping of the closed loop; , a pipe line for guiding the drain water of the steam water separator to the additional water supply heater for heat exchange and then supplying it to the water storage tank; a flow rate control valve installed in the pipe line; and one end connected to the water storage tank. and a pipe line whose other end communicates with the bottom of the feed water heater and whose other end communicates with the closed loose feed water heater inlet side pipe via a backup water pump.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment. Note that the same reference numerals are used for parts that are the same as in the prior art.

In Fig. 2, reference numeral 32 indicates an additional feed water heater (high pressure); High pressure (approx. 313-329℃, approx. 105-130kg)
/cma ) water (separated water) is guided through the pipe 33 and is supplied to the water storage tank 7 after heat exchange with the coolant (water) flowing in the closed loop of the steam generation system in a non-contact state. It is configured.

Further, the pipe line 33 is provided with a flow rate control valve 35 for adjusting the flow rate of the steam water separator drain water and suitably heating the feed water to the steam generator. Furthermore, water supply pump 1
2, a pipe line 34 is provided (broken), one end of which communicates with the bottom of the water storage tank 7 and the other end of which communicates with the pipe 21 via the backup water pump 30.

Next, residual heat removal from the plant by the steam generation system of the fast breeder reactor of the present invention configured as described above will be explained.

When the plant trips (when a reactor 1 rip or turbine trip occurs), the steam (accompanied by saturated water) generated by the residual heat of the plant from the steam generator closes the steam generator outlet steam stop valve 15. By operating the steam separator inlet steam stop valve 16 and opening the steam water separator inlet steam stop valve 17, the steam is introduced into the steam water separator 4, and steam and saturated water are separated. The separated IC steam passes through the main steam pipe 2 and further passes through the turbine bypass valve 14 and is dumped into the condenser 9.

On the other hand, for Nt saturated water (drain water), the steam-water separator 4 has a high JTE of about 105 to 130 k(]'/cm'a).
On the other hand, since the water storage tank 7 is operated at a low pressure of about 5 ka/cma, the pressure difference is sufficiently large. , is introduced into the additional feed water heater 32, where heat exchange is performed to heat the feed water to the steam generator 3, and then the water is transferred to the water storage tank 7.
By flowing into the water and mixing with relatively low temperature water from the condenser 9, it serves to maintain the stored water at a predetermined temperature 1 (approximately 150° C.) and pressure (approximately 5 kg/cm2).

Further, water is normally supplied to the steam generator 3 by using the water stored in the water storage tank 7 by driving the water supply pump 12.
If a situation occurs that impedes the smooth operation of the water supply pump 12 (for example, loss of regular power supply, etc.),
The backup water supply pump 3o is started by an emergency power supply (not shown), and the water is directly pumped to the front of the inlet side of the additional water heater 32 @21.
This ensures smooth steam generator operation.

As is clear from the above description, according to the present invention, turbine bleed air to the feed water heater is lost during a plant trip accompanied by a turbine trip or during isolated plant operation.
Even if the supply amount decreases significantly and the temperature of the water supplied to the steam generator drops, the high M, high pressure steam/moisture preheater drain water can be guided to the additional feed water heater (high pressure) for heat exchange. This makes it possible to maintain the temperature of the water supplied to the steam generator at approximately 250°C or higher, and the temperature of the steam water separator drain water discharged from the additional feedwater heater to be approximately 150°C.
Since the water is sufficiently hotter, by introducing it into the water storage tank, it can be mixed with the low temperature water from the condenser and the water stored in the water storage tank can be maintained at a predetermined temperature of about 150°C. Furthermore, even in the event of an abnormality/emergency of the water supply pump, such as when a power supply is lost, the water stored in the water storage tank maintained at the predetermined temperature can be supplied to the steam generator, thereby allowing the water to be supplied to the steam generator at a low temperature. That's not true (,
It is possible to obtain a steam generation system for a fast breeder reactor that can suppress thermal shock loads to the reactor system and secondary cooling system structures.

[Brief explanation of drawings]

FIG. 1 is a system explanatory diagram showing a steam generation system of a conventional fast breeder reactor, and FIG. 2 is a configuration explanatory diagram showing a steam generation system of a fast breeder reactor according to an embodiment of the present invention. 1... Nuclear reactor 3... Steam generator 4... Steam-water separator 6... Deaerator 7... Water storage tank
12... Water supply pump 30... Backup water supply pump 32... Additional water supply heater (high pressure) 33.34
...Pipe line 35...Flow rate control valve

Claims (1)

[Claims] In a steam generation system of a fast breeder reactor, the steam in the closed loop includes at least a closed loop that sequentially returns to the steam generator via a steam generator, a steam separator, a turbine, a condenser, a steam generator, and a water storage tank. An additional feed water heater is installed in the generator inlet piping. a flow rate control valve provided in the water storage tank; and a pipe line, one end of which communicates with the bottom of the water storage tank and the other end of which communicates with the additional feedwater heater inlet side piping of the closed loop via a backup water pump. A fast breeder reactor steam generation system characterized by: