JPS6332395A - Ventilation air-conditioning method in reactor housing fuel exchange bed - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for ventilation and air conditioning in a refueling floor of a reactor building of a nuclear power plant.

[Conventional technology]

In the reactor building refueling floor, a ventilation air conditioning system is installed to remove or dilute heat and suspended particles generated indoors, and fresh air is blown to the fuel exchange floor. Generally, the capacity of this device is determined based on the allowable radioactivity concentration and temperature in the room, but since this type of refueling floor is a large space, the ventilation device itself is large. ing.

The ventilation function depends on the number of ventilations and the wind speed, and conventionally it has been thought that the range of the number of ventilations and the wind speed as shown by region X in FIG. 1 is good.

Figures 2 and 3 show conventional general ventilation air conditioning systems. That is, a reactor well 1 and a fuel storage pool 2 are formed in the fuel exchange floor. On the other hand, along the wall on the opposite side of the pool 2, a large number of air outlets 4, 4, . Suction is carried out through a large number of suction ports 5, 5, . In addition, there are many suction lowers on the wall of pool 2.
7... is formed, and the radioactive mist evaporating from the pool 2 is suctioned and captured to prevent the spread of contaminated air. 8
is the equipment temporary storage pool.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional ventilation method, the number of ventilations is large, so the ventilation equipment is large (and uneconomical).

Therefore, it is better to keep the ventilation frequency as low as possible. The present inventors found that when reducing the number of ventilations, increasing the blowing wind speed;
A series of studies have found that it has the necessary ventilation function. This range is the range Y in FIG.

However, since this range of Y is a range of high wind speed,
The noise becomes louder, and the environmental conditions are not necessarily good for the sense of sensation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ventilation air conditioning method that uses a ceiling blowing system, which has not been used at all in the past, to reduce the number of ventilations while providing almost the same wind speed as conventional wall blowing.

[Means for solving problems]

The present invention for solving the above problems is as follows.

Fresh air is blown out from the ventilation and air conditioning outlet in the ceiling of the reactor building fuel exchange floor and sucked in through the floor inlet for ventilation and air conditioning. A method for ventilation and air conditioning in a refueling floor of a nuclear reactor building, which is characterized by providing ventilation and air conditioning.

...(1) However, vo: Outlet wind speed (m/5ec) Difference from temperature ("deg) N:
Number of ventilating air conditioning outlets t8: Outlet temperature ('C) h: Height of living area (m) [Function] According to the present invention, if the relationship of equation (1) above is satisfied, the number of ventilations can be reduced. Moreover, since fresh air can be supplied throughout the room, indoor radioactivity can be reduced by 4 degrees Celsius, and a predetermined temperature can be easily maintained.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in further detail along with experimental steps with reference to the drawings.

The present inventors investigated how ventilation frequency and wind speed affect ventilation function. However, since it is difficult to test with actual equipment, as shown in Figures 4 and 5,
A 1710-scale model similar to the actual reactor building refueling floor was constructed.

The similar model referred to here refers to a model in which the Archimedean number (Ar number) is matched as a dimensionless number that makes airflow phenomena similar, which is already known as a method for predicting indoor air distribution. This is a model made according to a relational expression in which the reference temperature difference (θ), the reference length/r, and the reference blowing wind speed (u) are expressed by the reduction ratio (n), that is, a similar equation.

In the present invention, a model was manufactured using a combination of reduction ratios.

In addition to the above model, a similar model with a scale (nt) = - was manufactured and used, and visual observation was performed by scattering visualization powder into an air flow. First, the results of airflow observation will be explained based on a 1/25 scale model.

Figures 6 to 10 show the conventional ventilation frequency C = 2.3 times/
hr and 1/3 C = 0.8 times/hr, blowing wind speed ■. These are the results when the velocity was changed to 15 m/s, 6 m/s, and 3 m/s, and the arrows in the figure indicate the wind direction. According to the results, when the wind speed is high, the airflow bounces off the floor and forms a circulating airflow at each outlet, which can potentially stir up radioactive dust accumulated on the floor and evaporated mist from the fuel pool. be.

On the other hand, if the wind speed is too low, there is a risk that fresh air will not reach the work area, although there is no risk of this happening.

Next, the number of ventilations C=0 using a similar model with a scale of 1/10.
The results of investigating the temperature distribution from 8 to 2.3 times/hr will be explained.

Figure 1) shows the outlet wind speed. These are the results of temperature distribution when is 9 m/s. According to this temperature distribution result, even if the conventional ventilation frequency (2.0 to 2.2 times/hr) is reduced to 1.5 times/hr, the air exchange rate is almost 4 liters on average at 16 points on each floor level. In addition, even if the conventional ventilation frequency is reduced to about half, the indoor temperature will only rise by about 0.5 to 1 degree. Therefore, according to the method of the present invention, It can be seen that even if the temperature is reduced by about half, the predetermined temperature can be sufficiently maintained.

Next, using a similar model with a scale of 1/25, we reduced the conventional ventilation frequency to about half, 1 time/hr, and examined the appropriate blowout speed in this case. As a result, the optimal blowing wind speed was 7.7 m/s ≧■. It has been found that a range of ≧5.0 m/s is preferable. Next, the temperature distribution in this wind speed range was investigated, and the results were as shown in FIG. As a result, it was found that the designed room temperature could be maintained within the same range.

From experiments on the striations, it was found that the Z range shown in FIG. 1 and the range expressed by formula (1) are preferable.

〔Effect of the invention〕

As described above, according to the present invention, the ventilation capacity can be reduced while maintaining the same wind speed as in the past, making it economical.

[Brief explanation of drawings]

Figure 1 is a ventilation frequency/wind speed correlation diagram showing the preferred wind speed range of the present invention, Figure 2 is a plan view of the conventional equipment, and Figure 3 is the m
-M line arrow view, Figure 4 is a plan view of the equipment with ceiling blowing according to the present invention, Figure 5 is a sectional view of the center side thereof, and Figures 6 to 1.
Figure 0 is a diagram showing the results of airflow observation, and Figures 1) and 12 are diagrams showing the experimental results of temperature distribution. i...Reactor well, 2...Fuel storage pool, 3.
...Blowout duct, 4...Blowout port, 5...Suction port,
6...Exhaust duct, 7...Suction port, 8...Equipment temporary storage pool. Figure 1 1.0 2.0 Renvt, I! IK C (1/hr) Figure 2, Figure 4, Figure 5. , 2.3°7h, Fig. 6 Va-15,0m/s. , 2.3! I/hr Figure 7 vol1)6. ○rn/s. 32.3yo71, Figure 8 Vo *3. Om/s. ,. , 8th, h, Figure 9 Vo+++5.0m/s

Claims (1)

[Claims] (1) Fresh air is blown out from the ventilation air conditioning outlet installed in the ceiling of the fuel exchange floor of the reactor building, and fresh air is sucked in through the inlet on the side wall to perform ventilation air conditioning, and the following relational expression (1) is used. A method for ventilation and air conditioning in a fuel exchange floor of a nuclear reactor building, characterized by performing ventilation and air conditioning with a blowout air velocity of . {(18.79x^3-198.0[CV△t/N(2
73+t_s)] x^2) (CV/N)^-^3^/^
2}^2^/^3}≧v_0≧{[18.79(x-h
)^3-198.0[CV△t/N(273+t_s)
] (x-h)^2] (CV/N)^-^3^/^2＝・
...(1) However, v_0: Outlet wind speed (m/sec) x: Height from floor to ceiling (m) V: Room volume (m^3) C: Ventilation frequency (times/hr) Δt: Outlet temperature and the indoor temperature (°deg) N: Number of ventilation and air conditioning outlets t_s: Outlet temperature (°C) h: Height of living area (m)