JP5603222B2 - Emergency gas processing apparatus and processing method thereof - Google Patents

Description

  The present invention relates to an emergency gas treatment device used in a nuclear power plant and an operation method thereof, and more particularly to an emergency gas treatment device effective for reducing radioactive substances released from the nuclear power plant and an operation method thereof.

  At a nuclear power plant, in the unlikely event of a nuclear accident, the radioactive material leaked from the nuclear containment vessel is removed, and the nuclear reactor building with the nuclear containment vessel is kept at a negative pressure and the nuclear reactor building is located. An emergency gas treatment device is provided for the purpose of preventing leakage of radioactive materials from the building (Patent Document 1).

  FIG. 5 is a diagram showing a configuration of a conventional emergency gas processing apparatus 20. In the event of a reactor accident, the fan 1 is started and the air in the reactor building is guided to the drying device 23 composed of the moisture removing device 2 and the heater 3 through the pipe 12 communicating with the inside of the reactor building. Reactor building air that has been dried and heated by the drying device 23 passes through a filter device 45 having a high-performance particle filter 4 and a charcoal filter 5 (hereinafter simply referred to as a charcoal filter) 5 for collecting radioactive substances, and is radioactive. Material is removed and released to the atmosphere. Among these constituent elements, the fan 1 and the heater 3 are dynamic devices that perform their functions by the drive unit, so that two series each having a capacity of 100% are installed from the viewpoint of maintaining the apparatus function, One of them is reserved. Patent Document 1 discloses an emergency gas processing apparatus having two lines in which the fan 1 and the drying device 23 are connected in series, and one line corresponding to the filter device 45 in the subsequent stage.

  Since the emergency gas treatment equipment is used in the event of an accident at a nuclear power plant, the atmosphere in the reactor building to be treated with the emergency gas treatment equipment is assumed to be 100% relative humidity. On the other hand, when the relative humidity is high, the performance of the charcoal filter 5 for iodine that captures radioactive iodine contained in the atmosphere of the reactor building is degraded. For this reason, in order to reduce the relative humidity of the processing air, the emergency gas processing device 20 has a drying device 23 composed of the moisture removing device 2 and the heater 3.

  Further, Patent Document 1 discloses that two heaters having 100% capacity are provided in an emergency gas processing apparatus drying apparatus constituted by one series.

JP 2006-90778 A

  In the conventional emergency gas processing apparatus (Patent Document 1) 20 having two series, in the event of a nuclear reactor accident, a predetermined time (hereinafter, referred to as two series simultaneous start-up operation), for example, 15 minutes during start-up operation. Both are operated, and then the normally operating one of the two systems is selected and the operation is continued. Therefore, during the two-line simultaneous start operation, the fan operates even if the heater 3 as a dynamic device does not operate normally, and the process air is supplied to the charcoal filter in a state where the relative humidity is high. That is, whether or not the environment is such that the charcoal filter performance can be exhibited is not the operating condition of the fan.

As a result, if one heater is broken during the two-line simultaneous start-up operation when the emergency gas processor is activated, the process air with high relative humidity is sent by the fan to the charcoal filter of the heater-failed line. There is a risk that the gas processing apparatus for use will not be able to demonstrate its performance.
When the fan 1 of the dynamic equipment fails, the processing air is not supplied to the charcoal filter, and thus the above problem does not occur.

  Further, the emergency gas processing device disclosed in Patent Document 2 is a device in which filter heaters are arranged in a series in series among fans and heaters that are dynamic devices, and 100% as spare devices. Two heaters having the capability are provided. Such a series of emergency gas processing apparatuses does not have the above-mentioned problems, and there is no suggestion of the problems in the entire disclosed contents. Therefore, there is no suggestion of a solution based on the problem.

  The present invention has been made to solve the above problems, and provides an emergency gas processing apparatus capable of preventing performance degradation of the emergency gas processing apparatus due to a heater failure during two-line simultaneous start-up operation and an operating method thereof The purpose is to do.

In order to achieve the above object, the present invention has at least the following features.
The present invention includes a fan, a moisture removing device that processes the processing air from the inside of the reactor building, and a drying device that includes a heater, and has the ability to process 100% of the radioactive substances in the processing air. In an emergency gas processing apparatus having two upstream stages and at least one downstream stage of a filter device including a high performance particle filter and iodine charcoal filter, the two upstream stages are activated simultaneously. The first feature is that it has means for preventing the performance degradation of the emergency gas treatment device due to the failure of the heater during the two-line simultaneous activation operation. That is, according to the present invention, during the two-line simultaneous starting operation, the fan is started without a heat input that is not heated by the heater, and air is not sent to the charcoal filter that cannot perform when the relative humidity of the processing air is high. It is characterized by that.

In addition, the present invention is characterized in that the suppression means comprises the heater having the capacity of 100% as a plurality of heaters having the capacity of 100% or less. A third feature is that a plurality of heaters are composed of two heating coils having 50% capacity.
Moreover, this invention makes it 4th characteristic to comprise the said several heater with a heater of a different kind.

Further, according to the present invention, the suppression means includes a detection means for detecting a failure of the heater, and a control means for stopping the operation of the fan of the series of the heater that has failed based on a detection result of the detection means. It has a fifth feature.
Further, according to the present invention, the detection means is provided on the upstream side of the heater, and the temperature difference between the temperature before heating of the processing air and the temperature after heating of the processing air provided on the downstream side of the heater. The sixth feature is to detect.

  In addition, the present invention provides two series, a high-performance particle filter and iodine, each having a fan, a moisture removing device for processing air from the reactor building, and a drying device having a heater. In an operation method of an emergency gas processing apparatus having at least one subsequent stage of a filter device having a charcoal filter, a failure of the heater during two-line simultaneous start-up operation in which the two previous-stage series are started simultaneously The seventh feature is that the operation of the fan of the series of the heaters that have failed is stopped based on the detection result.

  ADVANTAGE OF THE INVENTION According to this invention, the emergency gas processing apparatus which can prevent the performance fall by failure of a heater at the time of 2 series simultaneous starting operation, and its operating method can be provided.

It is a figure which shows the structure of the emergency gas processing apparatus which is the 1st Embodiment of this invention. It is a figure which shows the processing flow of the emergency gas processing apparatus which is the 1st Embodiment of this invention. It is a figure which shows the structure of the emergency gas processing apparatus which is the 2nd Embodiment of this invention. It is a figure which shows the structure of the emergency gas processing apparatus which is the 3rd Embodiment of this invention. It is a figure which shows the structure of the conventional emergency gas processing apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration of an emergency gas processing apparatus 20A according to the first embodiment of the present invention. The emergency gas treatment device 20A includes a fan 1, a moisture removing device 2, a drying device 23 having a heating coil 3 as a heater, a charcoal filter 5 for collecting radioactive substances, and a high performance particle filter on both sides of the charcoal filter 5. A filter device 45 having 4a and 4b is provided, and one series having a capacity of 100% for processing air from the inside of the reactor building is provided in two series in parallel. In addition, an upstream temperature sensor 9u for measuring the temperature of the processing air is connected to each line of the piping 12 and the fan 1 communicating with the inside of the reactor building, and the high performance particle filter 4a and the charcoal filter 5 on the drying device 23 side. A downstream temperature sensor 9d that measures the temperature of the processing air is also provided. Further, the emergency gas processing device 20A takes in the signals from the upstream temperature sensor 9u and the downstream temperature sensor 9d from the respective measurement lines 10u, 10d, and these take-in signals and commands from the host controller (not shown). The control device 8 controls the fan power unit 11 of the fans 1 of both systems and the heater power unit 31 of the heating coils 3 of both systems.

If a nuclear accident occurs, the control device 8 operates both fans 1 and the heating coil 3, that is, starts two-line simultaneous start-up operation (Step 1). The upstream temperature sensor 9u and the downstream temperature sensor 9d measure the temperature Tu of the processing air flowing into the emergency gas processing apparatus 20A and the temperature Td of the processing air before flowing into the charcoal filter 5 (Step 2). If the heating coil is operating normally, the processing air is heated and the downstream temperature sensor 9d rises. Then, after a predetermined time, for example, 15 seconds later, the temperature is raised to a predetermined temperature ΔT or more, and the temperature difference between the two satisfies the condition shown in Expression (1). On the contrary, if the heating coil is out of order, the processing air is not heated and the temperature of both is substantially the same, and the condition shown in the equation (2) is satisfied.
Td−Tu ≧ ΔT (1)
Td−Tu <ΔT (2)
Therefore, the presence or absence of a failure of the heating coil 3 is determined from the equations (1) and (2) (Step 3). If there is a failure, the failed fan is stopped (Step 4), The gas processing operation is continued (Step 5). If there is no failure, the two-line simultaneous start operation is continued as it is (Step 6), and even if the two-line simultaneous start operation is finished (Step 7), the operation according to the predetermined series is continued (Step 8).

  As a result, if either one of the heating coils 3 is out of order, the fan 1 is stopped. For example, the performance of the emergency gas treatment device is reduced only for 15 seconds of 15 minutes of the two-line simultaneous starting operation time. Thereafter, it is possible to prevent the use of the emergency gas processing apparatus in a state in which the performance is deteriorated. That is, since the fan operating condition is that the heating coil is operating normally, the fan does not operate when the heating coil fails, and the air in the reactor building is not sent to the charcoal filter where performance cannot be demonstrated. Therefore, it is possible to prevent the use of the emergency gas processing apparatus in a state where the performance is deteriorated.

  In the first embodiment described above, the installation positions of the upstream temperature sensor 9u and the downstream temperature sensor 9d are connected to the fan 1 of the pipe 12 communicating with the inside of the reactor building, respectively, and the high performance on the drying device 23 side. Although provided between the particle filter 4a and the charcoal filter 5, the upstream side temperature sensor 9u may be installed on the upstream side of the heating coil 3 so that the temperature of the processing air before heating the heating coil 3 can be measured. The downstream side temperature sensor 9d may be installed on the downstream side of the heating coil 3 as long as the temperature of the processing air after the heating coil 3 is heated can be measured for each series.

Next, the configuration of the emergency gas processing apparatus 20B according to the second embodiment of the present invention will be described with reference to FIG.
The configuration of the emergency gas processing device 20B according to the second embodiment is different from that of the emergency gas processing device 20A according to the first embodiment in that the fan 1 is downstream of the drying device 23 and further 2 downstream thereof. One filter device 45 common to two systems is provided. Note that the fans 1 may be provided for each series upstream of the drying device 23.

From the viewpoint of the present invention, since the temperature of the processing air heated by the heating coil 3 is separately measured for each series, the downstream temperature sensor 9d needs to be provided before the two processing airs merge. Therefore, in this embodiment, the downstream temperature sensor 9d is provided in the piping on the insertion side of the fan 1.
The installation position of the upstream temperature sensor 9u is the same as in the first embodiment. The processing by the control device 8 is basically the same as the processing flow shown in FIG. 2 as in the first embodiment.

  As described above, also in the second embodiment, as in the first embodiment, the heating coil 3 detects a failure due to the temperature difference between the upstream temperature sensor 9u and the downstream temperature sensor 9d and stops the fan 1 of the failed series. Thus, for example, the performance of the emergency gas treatment device is reduced only for 15 seconds of 15 minutes of the two-line simultaneous activation operation time, but thereafter, the use of the emergency gas treatment device in a state where the performance is lowered can be prevented.

  Next, the configuration of the emergency gas processing apparatuses 20C and 20d according to the third and fourth embodiments of the present invention will be described with reference to FIG. FIG. 4 shows another embodiment 23E of the drying device 23 shown in FIGS. 1 and 3, and an embodiment of the emergency gas processing device is obtained by changing the drying device 23 of FIGS. 1 and 3 to a drying device 23E. The emergency gas processing apparatuses 20C and 20D are configured.

  In the present embodiment, the heating coils 3 a and 3 b having 50% capacity are provided in parallel and can be driven separately by the heater power unit 31.

  As described above, there is a possibility that the performance of the emergency gas treatment device may be deteriorated due to the failure of the heating coil only during the two-line simultaneous start and the two-line simultaneous start operation. Since the startup operation is still in the initial state of the accident, it can be estimated that the relative humidity of the atmosphere of the reactor building, which is the process air, is not 100%. Further, since the charcoal filter is heated during standby, the temperature is higher than that of the processing air. For these reasons, compared with the design conditions required for the emergency gas processing apparatus, the heating coil heating capability required at the time of startup is small. From the above, by dividing the heating coil and heating the processing air as much as possible, the relative humidity can be lowered and the charcoal filter performance can be exhibited.

  As a result, since the probability that both of the heating coils 3a and 3b both fail is low, even if one of the heating coils 3a and 3b fails, it is possible to prevent the performance degradation of the emergency gas processing apparatus. In the third and fourth embodiments, the number of divisions may be three or more instead of two.

  In the present embodiment, as described above, the emergency gas processing apparatuses 20C and 20D do not necessarily need to be provided with the upstream temperature sensor 9u and the downstream temperature sensor 9d. In particular, it is not necessary to perform fan stop control due to temperature differences.

  As described above, also in the third and fourth embodiments, similarly to the first embodiment, even if a part of the heating coil 3 breaks down, the temperature of the processing air can be raised by another heating coil. In the operation time of 15 minutes, the performance degradation of the emergency gas treatment device can be surely prevented.

  In the first and fourth embodiments described above, the heating coil is used as the heater, but a panel heater or the like may be used. In the third and fourth embodiments, a heater having a capacity of 100% may be configured with different heaters.

1: Fan 2; Moisture removal device 3, 3a, 3b: Heating coil (heater)
4, 4a, 4b: High-performance particle filter 5: Charcoal filter for iodine 8: Controller 9u: Upstream temperature sensor 9d: Downstream temperature sensor 11: Fan power unit 12: Piping communicating with the reactor building 20, 20A, 20B, 20C, 20D: Emergency gas processing device 23: Drying device 31: Heater power unit 45: Filter device.

Claims (4)

Comprising: a fan, a front series two series that have a a drying device having a moisture removal device and heater treating process air from the reactor building in the high-performance particle filter and as Motoyo charcoal filters In the emergency gas processing apparatus having at least one series of subsequent stages of the filter device,
Detecting means for detecting a failure of the heater in order to suppress a deterioration in performance of the emergency gas treatment device due to a failure of the heater during a two-sequence simultaneous start operation in which the two sequences of the preceding stage are started simultaneously; An emergency gas processing apparatus comprising control means for stopping the operation of the fan of the heater series that has failed based on a detection result of the detection means . The detection means detects a temperature difference between a temperature before heating of the processing air provided on the upstream side of the heater and a temperature after heating of the processing air provided on the downstream side of the heating heater. The emergency gas processing apparatus according to claim 1 . A filter having a fan, a moisture removal device for treating the processing air from the reactor building, and a drying device having a heater and two preceding stages, a high-performance particle filter, and an iodine charcoal filter In the operation method of the emergency gas processing apparatus having at least one series of subsequent stages of the apparatus,
Detecting a failure of the heater at the time of a two-line simultaneous start operation in which the two series of the previous stage are started simultaneously, and stopping the operation of the fan of the series of the heater that has failed based on the detection result A method of operating an emergency gas treatment apparatus characterized by The detection is characterized in that a temperature difference between a temperature before heating of the processing air provided on the upstream side of the heater and a temperature after heating of the processing air provided on the downstream side of the heating heater is detected. The operation method of the emergency gas processing apparatus according to claim 3 .

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