Apparatus and method for measuring neutron beam of ex-vessel of small modular reactor

Abstract

Disclosed are an apparatus and a method for measuring a neutron beam of ex-vessel of a small modular reactor (SMR). The apparatus for measuring a neutron beam of ex-vessel of a small modular reactor of the present invention comprises: a detector for detecting a current generated by ionization of a neutron beam leaking from a reactor vessel; a preamplifier for receiving a current value of the detector to amplify the current value; a signal processing module for calculating the number and intensity of neutrons leaking in the reactor vessel on the basis of the current value amplified by the preamplifier; and a water level measurement device for transmitting a measurement value obtained by measuring the water level of a medium accommodated in the space between the reactor vessel and a containment vessel to the preamplifier, wherein the preamplifier holds gain value data determined in accordance with the water level of the medium and applies and compensates a gain value in accordance with the measurement value transmitted from the water level measurement device.

Description

Device and method for measuring the external neutron flux of a small modular nuclear power plant

[0001] The present invention relates to an apparatus and method for measuring an external neutron flux of a small modular reactor (SMR).

[0002] The off-core neutron flux monitoring system used in commercial nuclear power plants measures the output by measuring the neutron flux leaking from the reactor vessel, using a detector installed adjacent to the reactor vessel. The number of neutrons escaping from the reactor vessel is proportional to the reactor output. The detectors used in this process include fission chambers, uncompensated ion chambers, and proportional counters. The operating principle of the off-core neutron flux detector is that fast neutrons escaping from the vessel undergo fission with material on the detector surface, generating energetic fission fragments. These fission fragments ionize as they pass through a gaseous volume, generating an electric current. This current, which is extremely small, is amplified by a preamplifier and then transmitted to the control module. Because the off-core neutron flux described above is extremely small, the detector is installed adjacent to the reactor vessel for operation.

[0003] However, in dual-steel structures (reactor vessel and containment vessel installed outside of it) such as small modular reactors (SMRs), the installation of detectors outside the containment vessel rather than inside the reactor vessel is being considered to improve reactor coolant flow rate formation and ease of maintenance. When installing detectors outside the containment vessel in this way, the additional space between the reactor vessel and containment vessel causes more neutron flux moderation compared to commercial nuclear power plants, making the performance of the preamplifier very important. Furthermore, the medium in the space between the reactor vessel and containment vessel can vary depending on the plant operation mode, making it difficult to make accurate measurements when using existing preamplifiers and control modules.

[0004] Accordingly, the present invention has been proposed to solve the above-mentioned problem, and the purpose of the present invention is to provide an apparatus and method for measuring the external neutron flux of a small modular reactor (SMR) with a double steel structure, which can measure output through the external neutron flux without installing an external neutron flux detector outside the reactor vessel, which becomes an extreme environment in the event of an accident and cannot be maintained.

[0005] In addition, the present invention provides an off-site neutron flux measuring device and method for a small modular nuclear power plant, which can accurately measure neutron flux by actively reflecting environmental changes between the reactor vessel and the containment vessel, thereby diagnosing the exact status of the power plant.

[0006] In order to achieve the above object of the present invention, the present invention includes a detector for detecting a current generated by the ionization of neutron flux leaking from a reactor vessel, a preamplifier for receiving a current value of the detector and amplifying the same, a signal processing module for calculating the number and intensity of neutrons leaking within the reactor vessel based on the current value amplified by the preamplifier, and a level gauge for measuring a level of a medium contained in a space between the reactor vessel and a containment vessel and transmitting the measured value to the preamplifier.

[0007] The above preamplifier holds gain value data determined according to the water level of the medium, and provides an external neutron flux measuring device and method for a small modular nuclear power plant, which compensates by applying a corresponding gain value according to a measured value transmitted from the water level measuring device.

[0008] It is preferable that the detector be installed on the outside of the containment vessel.

[0009] When the medium in the space between the reactor vessel and the containment vessel is vacuum, it is preferable that the preamplifier retain gain value data in a vacuum state.

[0010] The present invention, by installing a detector outside the containment vessel, enables measurement of output through external neutron flux without installing an external neutron flux detector in an extreme environment outside the reactor vessel, which becomes an extreme environment in the event of an accident and is impossible to maintain, in a small modular reactor (SMR) with a double steel structure.

[0011] In addition, the present invention actively reflects environmental changes in the space between the reactor vessel and the containment vessel by adjusting the gain of the preamplifier using gain value data determined according to the level of coolant accommodated between the reactor vessel and the containment vessel, and enables accurate neutron flux measurement, thereby enabling accurate diagnosis of the status of the power plant.

[0012] FIG. 1 is a drawing for explaining the location where a detector of an off-site neutron flux measuring device of a small modular nuclear power plant is installed in order to explain an embodiment of the present invention.

[0013] Figure 2 is a diagram showing the main components of an external neutron flux measuring device of a small modular nuclear power plant to explain an embodiment of the present invention.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various other forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description have been omitted for clarity of description, and the same reference numerals will be assigned to identical or similar components throughout the specification.

[0015] Figures 1 and 2 are drawings for explaining an embodiment of the present invention, showing the main parts of an external neutron flux measuring device of a small modular nuclear power plant.

[0016] In a small modular nuclear power plant, a reactor vessel (30) is installed outside the core (10), and a containment vessel (50) is installed outside the reactor vessel (30). A space (70) is formed between the reactor vessel (30) and the containment vessel (50). This space (70) may be in a vacuum state or may be filled with coolant.

[0017] The external neutron flux measuring device of a small modular nuclear power plant of the present invention includes a detector (100), a preamplifier (200), a signal processing module (300), a water level measuring device (400), and a recorder (500).

[0018] The above detector (100) is installed on the outside of the containment vessel (50). The detector (100) can detect current generated by neutron flux leaking from the reactor vessel (30). That is, the detector (100) can obtain a current signal by applying a direct current voltage.

[0019] The preamplifier (200) amplifies the current detected by the detector (100) because it is a very small value and transmits it to a control module such as a signal processing module (300).

[0020] The preamplifier (200) of the embodiment of the present invention holds gain value data determined according to the medium of the space (70) between the reactor vessel (30) and the containment vessel (50). That is, the preamplifier (200) holds gain value data determined according to the shape of the medium of the space (70): a vacuum state, a state in which the detector (100) installation area is partially filled with water, or a state in which the detector (100) installation area is completely filled with water. This preamplifier (200) is intended to compensate for a decrease in a measured value due to a change in the medium by varying the detector gain according to the shape of the medium of the space (70).

[0021] The signal processing module (300) can obtain the number and intensity of neutrons leaking from the reactor vessel (30) based on the current value amplified by the preamplifier (200).

[0022] The water level gauge (400) can measure the water level of the medium contained in the space (70) between the reactor vessel (30) and the containment vessel (50) and transmit the measured value to the preamplifier (200).

[0023] Meanwhile, the recorder (500) can record and display data of the signal processing module (300) in a storage device.

[0024]

[0025] The method for measuring the external neutron flux of a small modular nuclear power plant according to the embodiment of the present invention is described as follows.

[0026] The operating principle of the off-core neutron flux detector is that fast neutrons emitted from the reactor vessel (30) undergo fission with material on the detector surface, generating energetic fission fragments. These fission fragments then ionize as they pass through the gaseous volume, generating an electric current. This current is amplified by a preamplifier and transmitted to the control module.

[0027] That is, neutrons generated in the core (10) escape from the reactor vessel (30), pass through the medium of the space (70) between the containment vessel (50) and the reactor vessel (30), and pass through the containment vessel (50) to be transmitted to the detector (100).

[0028] And the detector (100) detects the current generated by applying a direct current voltage and transmits the detected current value to the preamplifier (200).

[0029] Meanwhile, the water level gauge (400) measures the water level of the medium in the space (70) between the reactor vessel (30) and the containment vessel (50) and transmits the measured water level value to the preamplifier (200). The measured value from the water level gauge (400) is measured in the range of a state in which the detector (100) installation area is partially filled with water or a state in which the detector (100) installation area is completely filled with water, that is, in the range of 0 to 100%, and is transmitted to the preamplifier (200).

[0030] The preamplifier (200) has gain value data determined according to the water level of the medium, so it compensates by applying the gain value according to the measured value transmitted from the water level measuring device (400) and transmits the compensated value to the signal processing module (300).

[0031] This signal processing module (300) obtains the number and intensity of neutrons leaking from the reactor vessel (30) based on the current value amplified by the preamplifier (200) and transmits the same to the recorder (500).

[0032] This embodiment of the present invention installs the detector (100) outside the containment vessel (50) so that the number and intensity of neutrons, which vary depending on the type of medium in the space (70), are changed by changing the gain of the preamplifier (200) according to the medium. Therefore, this embodiment of the present invention can implement the same performance as installing the detector (100) directly outside the reactor vessel (30).

[0033] Meanwhile, if the medium of the space (70) between the reactor vessel (30) and the containment vessel (50) is in a vacuum state, the preamplifier (200) can receive information about the vacuum state through a separate sensor (not shown) or device. Then, since the preamplifier (200) has gain value data determined according to the vacuum state, it can apply the gain value according to the vacuum state and transmit a signal to the signal processing module (300).

[0034] The present invention can perform output measurement through external neutron flux without installing an external neutron flux detector in an extreme environment outside the reactor vessel (30) where maintenance is impossible and an extreme environment occurs in the event of an accident in a small modular reactor (SMR) with a double steel structure.

[0035] In addition, the present invention adjusts the gain of the preamplifier using gain value data determined according to the level of coolant accommodated between the reactor and the containment vessel, thereby actively reflecting environmental changes between the reactor and the containment vessel, enabling accurate neutron flux measurement, and thus enabling accurate diagnosis of the status of the power plant.

[0036]

[0037] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. A detector that detects the current generated by the ionization of neutron flux leaking from the reactor vessel. A preamplifier that receives the current value of the above detector and amplifies it, A signal processing module that calculates the number and intensity of neutrons leaking within the reactor vessel based on the current value amplified by the preamplifier; and A level gauge that measures the level of a medium contained in the space between the reactor vessel and the containment vessel and transmits the measured value to the preamplifier. Including, The above preamplifier An external neutron flux measuring device for a small modular nuclear power plant that holds gain value data determined according to the water level of the above medium and compensates by applying a corresponding gain value according to the measured value transmitted from the water level measuring device.

2. In claim 1, The above detector An external neutron flux measuring device for a small modular nuclear power plant installed on the outside of the above containment vessel.

3. In claim 1, If the medium in the space between the reactor vessel and the containment vessel is vacuum, The above preamplifier An off-core neutron flux measuring device for a small modular nuclear power plant with vacuum-state gain data.

4. A method for measuring the external neutron flux of a small modular nuclear power plant using the external neutron flux measuring device of a small modular nuclear power plant described in any one of claims 1 to 3.

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