JPS594802A - Steam generator - 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 generator, and particularly to a shell-and-tube type liquid sodium heated steam generator suitable for use in a fast breeder reactor.

In a conventional shell-and-tube steam generator, the steam outlet tube plate 81! If there is a difference between the width and the sodium population t7JJj, there is a drawback that thermal shock is applied to the tube sheet when steam ventilation is fully started. For example, after a plant trip, when the water supply is stopped, the temperature of the tubesheet slowly decreases, while the sodium is cooled by the air cooler and continues to decrease in temperature.

For this reason, a temperature difference occurs between the sodium and the tube sheet, and when steam ventilation is started for restart, the steam becomes almost 4 degrees Celsius with the sodium, resulting in a thermal shock being applied to the tube sheet.

An object of the present invention is to completely alleviate such thermal shock to the tubesheet.

The present invention focuses on the fact that the outlet steam temperature is mainly determined by the sodium chloride temperature, and is almost equal especially at low flow rates, and by making the tube sheet temperature and the inlet sodium temperature equal, Thermal shock by reducing the difference in steam temperature?
It is a relief.

Hereinafter, an embodiment using a heat pipe as a means for equalizing the sodium temperature and the tube sheet temperature will be described with reference to FIG. 1. The steam generator is composed of a cylindrical shell 1 and a number of heat transfer tubes 2 spirally wound therein. Sodium, which is a heating fluid, is supplied to the steam generator shell side through the supply pipe 3i, exchanges heat with the water in the heat exchanger tube, and then passes through the outlet pipe 4.
is discharged from. On the other hand, water, which is the fluid to be heated, is distributed to a large number of heat transfer tubes through the water supply header 5, and after descending through the downcomer section, it ascends through the spiral heat transfer tubes, exchanging heat with sodium, preheating, boiling, and superheating. It becomes steam. Steam from a large number of heat exchanger tubes is collected in the tube plate section 6 and sent to the steam header 7. The steam at the outlet of the heat exchanger tube should have a temperature close to that of the supplied sodium; especially when the feed water flow rate is small, the temperatures of the steam and sodium will be almost equal. The sodium supply pipe and the tube plate are connected by a heat vibrator 8, so that the temperature of the tube plate can follow the temperature of the supplied sodium. According to this embodiment, since both the tube sheet temperature and the steam temperature are close to the sodium temperature, the temperature difference between the two becomes small, and thermal shock to the tube sheet portion can be alleviated.

According to the present invention, even if the temperature of sodium, which is the heating fluid, changes, the temperature difference between the tubesheet and steam can be kept small, so the thermal shock applied to the tubesheet is alleviated, and the tubesheet remains healthy. It has the effect of increasing sex.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing changes in sodium and tube sheet temperature when the plant is restarted after a plant trip.

Claims (1)

[Claims] 1. Liquid heating fluid on the pipe side? A shell-and-tube type steam generator in which heated fluid flows through the sink/L side for heat exchange, and has means for equalizing the heated fluid outlet tube plate temperature and the heated fluid inlet temperature. 2. In order to equalize the tube sheet temperature and the heating fluid input temperature, is there a means for transmitting heat between the tube sheet and the heating fluid? A steam generator according to claim 1, characterized in: 3. Using a heat pipe as a means to transfer heat between the tube plate and the heating fluid? A steam generator according to claim 1, characterized in: