JPS62129791A - Decay-heat removing operating method - 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 [Technique of the Invention i.1: Field of the Invention] The present invention relates to a decay heat removal operation method for removing decay heat of a fast breeder reactor.

[Technical background of the invention and its problems] The fast breeder reactor, which burns fissile material to extract energy and breed useful fissile material from the parent fuel material, is currently undergoing research and development as an effective nuclear reactor. It is progressing.

FIG. 3 shows the main parts of an example of such a fast breeder reactor plant, and in the figure, reference numeral 1 indicates a steam generator. A liquid sodium inlet pipe 2 and a liquid sodium outlet pipe 3 for flowing liquid sodium are connected to the high temperature side of the steam generator 1, and to the low temperature side,
The steam generated in the steam generator 1 is sent to a turbine (not shown) through a main steam pipe 4, and from a condenser (not shown) via a deaerator 5, a feed water pump 6, and a feed water heater 7. A water supply pipe 8 that supplies water to the steam generator 1 is connected thereto.

Note that a water supply adjustment valve 9 for adjusting the water supply flow rate is inserted into the water supply pipe 8.

Additionally, a recirculation system is added around the steam generator 1, which is used only when starting and stopping the fast breeder reactor.
This recirculation system runs from the main steam pipe 4 to the steam separator 10.
Introductory piping 11 for introducing steam into the water separator 10
steam pipe 12 without returning the steam separated to the main hot air pipe 4;
Recirculation piping 13 and recirculation pump 14 for recirculating the separated water to the steam generator 1 and valves 15.16.1 inserted in each piping to switch these flow paths.
7 and check valves 18 and 19.

In the high speed increase TJli'1 reactor plant with the above configuration, the thermal energy generated in the reactor core is extracted by circulating liquid sodium, the water supplied from the water supply pipe 8 is vaporized in the steam generator 1, and the water supplied from the main steam pipe 8 is to the turbine, which rotates the turbine.

A portion of the steam is introduced into the high temperature side of the feed water heater 7 to heat the feed water.

When the reactor core is shut down in such a fast breeder reactor plan I, it is necessary to remove decay heat, so the feed water pump 6 continues to operate, and the water supply to the steam generator 1 is continued. However, when the decay heat is removed in this way, the temperature of the feed water at the outlet of the heater 7 decreases to the saturation temperature of the deaerator 5. Along with this, the temperature of the liquid sodium thorium at the outlet of the steam generator 1 also decreases.If this temperature decreases too much, a large thermal shock will occur at the outlet liquid sodium nozzle of the steam generator 1. In addition, there is a risk that the salmon quality and safety of the plant will be compromised.

[Objective of the Invention] The present invention has been made in response to such problems, and improves the health and safety of fast breeder reactor plans 1 to 1 by mitigating the thermal shock applied to the liquid sodium nozzle at the outlet of the steam generator. The purpose of the present invention is to provide a decay heat removal operation method that can prevent damage to the decay heat.

[Summary of the Invention] In other words, the present invention provides a decay system in which water is supplied to the low-temperature side of a steam generator, and the liquid 1 to 1 noum circulated to the high-temperature side of the steam generator is cooled to remove decay heat. In the heat removal operation method, water is supplied to the steam generator from a condenser, and
The steam generated in the steam generator is introduced into a steam-water separator in a recirculation system, and the water separated by the steam-water separator is recycled to the steam generator, and Monitor the liquid sodium outlet temperature and temperature change rate, and if the liquid sodium outlet temperature and temperature change rate exceed the preset 1st shift, 1lii+' from each δ2 constant 1st shift. By reducing the water supply stream from the condenser according to the difference,
The thermal shock applied to the liquid sodium nozzle at the exit of the steam generator can be alleviated to prevent damage to the safety and performance of the fast breeder reactor plant.

[Embodiment of the Invention] Hereinafter, details of the method of the present invention will be explained with reference to the drawings for one embodiment.

FIGS. 1d and 2 show the configuration of a fast breeder reactor plant in which a control device and a control device used in the method of one embodiment of the present invention are arranged. Note that the same parts as those in the fast breeder reactor plant shown in FIG. 3 are given the same reference numerals and redundant explanations will be omitted.

In FIGS. 1 and 2, reference numeral 5Q20 indicates a control device. This control device 20 is inputted with the inlet liquid sodium temperature of the steam generator 1 and determines the feed water flow rate. A function generator 21 outputs a target value, and a temperature of the outlet liquid sodium of the steam generator 1 is compared with a preset temperature setting point. If the temperature drops below this temperature 32, the temperature monitoring device 22 decreases and corrects the feed water flow rate target value according to the deviation. A differentiator 23 outputs the rate of change, and the output from this differentiator 23 is input, and this temperature change rate is compared with a preset temperature change rate setting value to determine whether this temperature change rate or the temperature change rate set value If the water flow exceeds m
It is comprised of a temperature change rate monitoring device 24 that corrects the target value by decreasing it, and a feed water regulating valve control device 25 that receives the feed water flow rate target value and the feed water flow rate and controls the feed water regulating valve according to one deviation thereof.

In the method of this embodiment, when the decay heat is removed, first the valve 158 for exchange of the flow path 1.7I is closed, and the steam generated in the steam generator 1 is transferred to the steam separator 10 with the valve 1G in between. The control device 20 is activated when the controller 20 is guided.

The control device 20 determines the water supply flow rate depending on the temperature of the liquid at the inlet of the steam generator 1, and
Monitor the output liquid temperature and temperature change rate of the steam generator 1, and if one or both of these exceed a preset set value, reduce the feed water flow rate target value; 4 Correctly, if the feed water temperature drops suddenly, the output of the steam generator 1 can be reduced by adjusting the feed water flow rate.
'') Prevents thermal shock from bending to the 1-piece tsutorium nozzle part.

The steam-driven water supply pump 6 becomes difficult to operate as steam decreases, so when the separated water is stored in the steam-water separator 10 and the water level rises to a certain extent, the valve 17 is closed. The water separated in the steam/water director 10 is recirculated into the steam generator 1 by a motor-driven recirculation pump 14.

In addition, in the decay heat removal operation method of this embodiment described in Section 3, the feed water flow rate is adjusted while monitoring the liquid sodium temperature on the outlet side of the steam generator 1 and its temperature change rate, and the re-i! i! After the water separated and stored by the steam separator 10 of the ili system reaches a certain level,
Instead of the steam-driven feed water pump 6, a motor-driven recirculation pump 1/1 is used to recirculate this water into the steam generator, so that due to the loss of one heat steam source per year, the water is removed from the II water heater. The thermal shock applied to the outlet liquid sl helium nozzle portion of the steam generator 1 due to the rapid temperature drop of the feed water can be significantly alleviated.

In the method of this embodiment, the feed water flow rate target value was set by inputting the inlet temperature of the steam generator 1 into the function generator 21, but the present invention) It goes without saying that the target value of the water supply flow rate may be set as a function of time, etc., without being limited thereto.

[Effect of the invention] As described above, the decay heat removal operation method of the present invention)
Steam generation and evaporation liquid No. 1 due to sudden drop in feed water temperature
It is possible to alleviate the thermal shock applied to the single symnosule part and prevent damage to the integrity and safety of the Fast Breeder Reactor Plan 1.

[Brief explanation of drawings]

FIG. 1 shows one of the control devices used in the method of one embodiment of the present invention.
Rib showing 14 formations [1st figure, 2nd figure is based on 11th figure]
Piping system diagram of a fast breeder reactor plant with control head arranged, Figure 3 (J, is a room layout system diagram of fast breeder reactor plan 1~. 1... Steam generation Container 2...Liquid tank [・1 unit inlet piping 3・
......) Hei 1 Hona (~Rium outlet piping 4...
......Main steam piping 8...Water supply color scheme 10...Steam water separator 20...Control port a 21...Function generator 22...Temperature monitoring device 23...Differentiator

Claims (1)

[Claims] (1) In a decay heat removal operation method in which water is supplied to the low temperature side of the steam generator and liquid sodium circulated to the high temperature side of the steam generator is cooled to remove decay heat, condensate water is supplied to the steam generator. At the same time, the steam generated in the steam generator is introduced into a steam-water separator in a recirculation system, and the water separated by the steam-water separator is recycled to the steam generator, and , the liquid sodium outlet temperature and temperature change rate of the steam generator are monitored, and if the liquid sodium outlet side temperature and temperature change rate exceed respective preset set values, the respective settings are changed. A decay heat removal operating method characterized in that the flow rate of water supplied from the condenser is reduced in accordance with the deviation from the value.