JPH06174885A - Auxiliary equipment cooling system equipment - Google Patents

Abstract

(57) [Summary] [Structure] Circulation pump 1, heat exchanger for cooling cooling water 2,
It is composed of a pipe 9 forming a closed loop, an auxiliary machine cooling water flow rate depending on a plant operation mode, and a heavy water cooler 3, a steam discharge pool cooler 6 and other auxiliary machines 10 which are connected in series. The heavy water cooler 3 is connected to the downstream side of the steam discharge pool cooler 6. During normal plant operation, there is no heat load on the steam discharge pool cooler 6, so the inlet temperature of the heavy water cooler 3 becomes the same as that of the other auxiliary equipment 10, and there is no problem in heavy water temperature constant control. [Effect] By connecting the auxiliary equipment in series in the auxiliary equipment cooling system equipment where the heat load does not change much between normal operation and abnormal operation of the heavy water deceleration reactor plant, and the auxiliary equipment that supplies cooling water is different. , The heavy water cooler temperature control valve bypass valve and the steam discharge pool cooler electric valve can be deleted without switching the valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy water deceleration-type nuclear reactor, in which the heat load is almost the same during normal operation and during abnormal times, the auxiliary equipment for passing cooling water is different, and the switching operation of the water passing auxiliary equipment is performed. This eliminates the need to change the operating state of the necessary auxiliary equipment cooling system equipment.In particular, the valve switching operation is not performed during normal plant operation and during abnormal conditions, and water flow during normal plant operation and during abnormal conditions The present invention relates to an auxiliary equipment cooling system facility in which the operating state of a system is made constant by connecting different auxiliary equipment in series.

[0002]

2. Description of the Related Art Auxiliary equipment cooling system equipment in a heavy water deceleration type nuclear power plant cools cooling water whose pressure has been boosted by a circulation pump with a heat exchanger, passes the water to each auxiliary equipment, and exchanges heat with each auxiliary equipment. It has a closed loop configuration that returns cooling water to the circulation pump. Among the auxiliary machines, the heavy water cooler is an auxiliary machine for keeping the temperature of heavy water, which is a moderator held in the calandria tank during the normal operation of the plant, constant, and is about 70% of the heat removal amount of the auxiliary system cooling system.
Occupy Since the reactor is shut down when the plant is abnormal, the calorific value of heavy water, which is a moderator, sharply decreases as the reactor output decreases, so the required heat removal amount in the heavy water cooler is about 20% of 10 ×. It is reduced to 10 ⁶ kcal / h.

On the other hand, the steam discharge pool cooler has no heat load because the water temperature of the steam discharge pool does not rise during normal plant operation. Also, when the plant is abnormal, high temperature steam from the safety valve etc. is released to the steam release pool,
The water temperature of the steam discharge pool rises, the required heat removal amount in the steam discharge pool cooler increases, and accounts for about 30% of the heat removal amount of the auxiliary equipment cooling system when the plant is abnormal.

As described above, the heavy water deceleration type nuclear power plant is characterized in that the heat load generating auxiliary equipment of the auxiliary equipment cooling system equipment is different during normal operation of the plant and during abnormal times. Therefore, in order to reduce the circulation flow rate of the auxiliary equipment cooling system, it is necessary to switch the water auxiliary equipment during normal operation of the plant and during abnormal operation.

That is, when the heavy water cooler is switched from the normal operation of the plant to an abnormal state, the temperature control valve is switched to the temperature control valve bypass valve to reduce the auxiliary cooling water flow amount, and the steam discharge pool cooler is used for the normal operation of the plant. When switching from time to time in an abnormal condition, the motor-operated valve is closed to full open to start the flow of auxiliary machine cooling water.

Therefore, the auxiliary equipment cooling system facility requires an operation mode detection signal for opening and closing the valve and an automatic valve switching signal.

[0007]

FIG. 2 shows an example of auxiliary equipment cooling system equipment using a conventional technique of a heavy water moderator reactor.

The heavy water cooler 3 provided to keep the temperature of the heavy water which is the moderator during the normal operation of the plant is an auxiliary machine cooling water which is a cooling water so that the temperature of the heavy water inlet to the calandria tank becomes constant. Flow rate of about 2300m with temperature control valve 4
Controlled to ³ / h. When the plant is abnormal, the temperature control valve 4 is fully closed and the bypass valve 5 is left open to ensure the required flow rate of 600 m ³ / h at the time of abnormality. Further, in the steam discharge pool cooler 6 provided to suppress the rise in the water temperature of the steam discharge pool 8 due to the inflow of high-temperature steam at the time of plant abnormality, the motor-operated valve 7 is fully closed during normal plant operation, When the plant is abnormal, the valve is opened for about 14
The water temperature of the steam discharge pool 8 is 7 after passing 00 m ³ / h.
I try not to exceed 0 ℃.

[0009] Thus, the plant normally required flow rate 2300 m ³ / h of heavy water cooler during operation, the abnormal time, heavy water cooler required flow rate 600 meters ³ / h and the vapor discharge pool condenser required flow rate 1400 m ³ / h with accessory Since the flow rate of water as the cooling system equipment is almost the same, it was necessary to open and close the valve by the plant operation mode switching signal.

An object of the present invention is to provide an auxiliary equipment cooling system equipment which does not require valve switching operation even when the plant operation mode is changed.

[0011]

The above object is to connect a steam discharge pool cooler and a heavy water cooler in series so that the total heat load in both normal operation and abnormal operation of the plant becomes the same by switching the plant operation mode. It is achieved by connecting and passing water through the steam discharge pool cooler and then through the heavy water cooler.

[0012]

The basic operation of the present invention will be described below with reference to FIG.

In the figure, by connecting the steam discharge pool cooler 6 and the heavy water cooler 3 in series, during normal plant operation, the steam discharge pool cooler 6 having no heat load is passed through the heavy water cooler 3 after passing water. Therefore, the outlet temperature of the steam discharge pool cooler 6 becomes the same as the inlet temperature of the heavy water cooler 3 of the prior art, and there is no problem in the heavy water temperature constant control of the heavy water cooler 3.

When the plant is abnormal, the steam discharge pool cooler 6 removes heat, and then water is passed to the heavy water cooler 3. However, the heavy water cooler 3 has a lower heat removal amount than that during normal plant operation, and With the increase in the auxiliary cooling water flow rate (the same flow rate as during normal plant operation) compared to technology, the steam cooling pool cooler 6 temperature of the auxiliary cooling water after heat removal and the auxiliary cooling water flow rate are sufficient for the heavy water cooler. The heat load can be removed. Therefore,
The heavy water cooler temperature control valve bypass valve 5 is not necessary because the valve switching operation is not necessary.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In the figure, the steam discharge pool cooler 6 and the heavy water cooler 3 are connected in series unlike other auxiliary machines.

According to this embodiment, during normal plant operation,
After passing the steam discharge pool cooler 6 having no heat load, the water is passed to the heavy water cooler 3. From this, since the auxiliary machine cooling water outlet temperature of the steam discharge pool cooler 6 is not different from the inlet temperature, the auxiliary machine cooling water inlet temperature of the heavy water cooler 3 becomes the same as the conventional inlet temperature, There is no problem in constant control of heavy water temperature.

When the plant is abnormal, the required UA value of the steam discharge pool cooler 6 (heat transfer area x overall heat transfer coefficient) is about 6 x 1
0 ⁶ kcal / h ° C., inlet temperature of auxiliary machine cooling water 32 ° C., and amount of auxiliary machine cooling water 2300 m ³ / h, heat exchange amount (Q) =
UA value × logarithmic mean temperature difference (ΔT _m ) = flow rate (W) × specific gravity (γ)
The heat removal amount is about 1 due to the relationship of x specific heat ( _Cp ) x temperature difference (ΔT)
Since it is 6 × 10 ⁶ kcal / h, the heat removal amount of the conventional technology is 15
× 10 ⁶ kcal / h can be secured. At this time, the outlet temperature of the auxiliary machine cooling water is about 40 ° C., and the auxiliary machine cooling water at this temperature is supplied to the heavy water cooler 3. That is, the outlet temperature of the steam discharge pool cooler 6 becomes the inlet temperature of the heavy water cooler. The required amount of heat exchange for the heavy water cooler during normal plant operation is approximately 42 × 10 ⁶ kcal / h in order to keep the temperature of the heavy water, which is the moderator, constant. About 1 calorific value of heavy water
It is reduced to 0 × 10 ⁶ kcal / h. Therefore, even if the auxiliary cooling water inlet temperature of the heavy water cooler rises from 32 ° C in normal times to about 40 ° C in abnormal times, the auxiliary cooling water flow rate is 2300 m ³ / h, which is the same as in normal plant operation. When the required UA value of the heavy water cooler is 3 × 10 ⁶ kcal / h ° C, the heat removal amount is 20
× 10 ⁶ kcal / h, which is the required heat removal amount of 10 × 10 ⁶ kca
1 / h can sufficiently remove heat.

As described above, by connecting the steam discharge pool cooler and the heavy water cooler in series, it is not necessary to open / close the common valve at the time of normal plant operation. The bypass valve 5 is unnecessary, and the temperature control valve 4 alone can be operated. Further, the electric valve 7 of the steam discharge pool cooler 6 is also unnecessary, and the need for valve operation for switching the plant operation mode is eliminated by installing only a manual valve for maintenance.

In this embodiment, an example in which a heavy water cooler is connected on the downstream side of the steam discharge pool cooler is shown, but this effect can be expected even if the connection order is reversed.

[0021]

According to the present invention, the heat load of the auxiliary equipment cooling system equipment does not change significantly even when the plant state changes, and in the auxiliary equipment cooling system equipment through which water is passed, the valve accompanying the change of the operating state The operation can be simplified because the extra valve can be deleted without switching operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an accessory cooling system facility of the present invention.

FIG. 2 is a block diagram of auxiliary equipment cooling system equipment using a conventional technique.

[Explanation of symbols]

1 ... Circulation pump, 2 ... Heat exchanger, 3 ... Heavy water cooler, 4 ...
Heavy water cooler temperature control valve, 5 ... Temperature control valve bypass valve, 6
... Steam release pool cooler, 7 ... Motorized valve, 8 ... Steam release pool, 9 ... Piping, 10 ... Auxiliary equipment.

Claims (1)

[Claims] 1. A cooling system facility for a heavy water deceleration type reactor in which the heat load is almost the same when the plant is in normal operation and when it is abnormal, and the auxiliary device for passing the cooling water is different and the switching operation of the water passing auxiliary device is required. 2. The auxiliary equipment cooling system facility, wherein the auxiliary equipment is connected in series, and it is not necessary to change the auxiliary equipment through which water is passed during normal operation and abnormal conditions.