A method for measuring the reactivity value of control rods in high temperature gas-cooled reactors

Abstract

The present invention provides a method for measuring the reactivity value of a control rod of a high temperature gas-cooled reactor, comprising the following steps: step S1, the measured rod is located at a first preset position, the reactivity compensation rod is located at a second preset position; the power compensation rod is located at a preset high position; step S2, starting the reactor and measuring the first doubling cycle; step S3, adjusting the position of the measured rod and lifting the power compensation rod; measuring the second doubling cycle; step S4, adjusting the position of the reactivity compensation rod and lifting the power compensation rod, measuring the third doubling cycle; step S5, repeating steps S3 to S4, and calculating the reactivity value of the measured rod from each progressive cycle of the reactor. A technical effect of the embodiment of the present application is that the design is reasonable, the reactivity value of the control rod can be accurately measured, and the operability is good.

Description

Technical Field

[0001] The invention belongs to the technical field of high temperature gas-cooled reactor commissioning and operation, and in particular relates to a method for measuring the reactivity value of a control rod of a high temperature gas-cooled reactor. Background Art

[0002] The pebble bed high temperature gas-cooled reactor is designed with two reactivity control systems on the graphite side reflector layer, one is the control rod system, and the other is the independent absorption ball shutdown system with different working principles. Among them, the control rod system is the main reactivity control means, which realizes the following functions: 1) reactivity control of operating conditions such as reactor startup, power increase and decrease, and normal power operation adjustment; 2) emergency shutdown; 3) using only the control rod system, the reactor can reach and maintain a normal shutdown state.

[0003] In actual applications, pressurized water reactor nuclear power plants have also designed similar control rod systems, and the reactivity value of control rods can be measured through boron adjustment method, dynamic rod engraving method, rod drop method, etc. Among them, the reactivity meter plays a key role in the above control rod value measurement methods.

[0004] Due to the different characteristics of high temperature gas-cooled reactors and pressurized water reactors, the current reactivity instrument cannot be applied to high temperature gas-cooled reactors and measure the reactivity value of control rods of high temperature gas-cooled reactors. Therefore, a measurement method is urgently needed to accurately measure the reactivity value of control rods. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a new technical solution for a method of measuring the reactivity value of control rods of a high temperature gas-cooled reactor.

[0006] According to one aspect of an embodiment of the present application, a method for measuring the reactivity value of a control rod of a high temperature gas-cooled reactor is provided, comprising the following steps:

[0007] Step S1, determining the measured rod, the reactive compensation rod and the power compensation rod, so that the measured rod is located at a first preset position, the reactive compensation rod is located at a second preset position, and the reactive compensation rod is used to perform reactive compensation on the measured rod; the power compensation rod is located at a preset high position;

[0008] Step S2, starting the reactor, allowing the reactor to reach and maintain a stable first doubling period; measuring the first doubling period, and inserting the power compensation rod to control the power of the reactor;

[0009] Step S3, adjusting the position of the measured rod and lifting the power compensation rod, so that the reactor reaches and maintains a stable second doubling period; measuring the second doubling period, and inserting the power compensation rod to control the power of the reactor;

[0010] Step S4, adjusting the position of the reactive compensation rod and lifting the power compensation rod, so that the reactor reaches and maintains a stable third doubling period; measuring the third doubling period, and inserting the power compensation rod to control the power of the reactor;

[0011] Step S5, repeating steps S3 to S4, obtaining each progressive cycle of the reactor according to each doubling cycle of the reactor, and calculating the reactivity value of the measured rod according to each progressive cycle of the reactor.

[0012] Optionally, in step S1, one of the first preset position and the second preset position is at an upper part of a core of the reactor, and the other is at a lower part of the core of the reactor.

[0013] Optionally, the measured rod is located at the upper part of the core of the reactor, and the reactive compensation rod is located at the lower part of the core of the reactor;

[0014] In step S3, the position of the measured rod is adjusted to insert the measured rod downward;

[0015] In step S4, adjusting the position of the reactive compensation rod is to lift the reactive compensation rod.

[0016] Optionally, the measured rod is located at the lower part of the core of the reactor, and the reactive compensation rod is located at the upper part of the core of the reactor;

[0017] In step S3, adjusting the position of the measured rod is to lift the measured rod;

[0018] In step S4, the position of the reactive compensation rod is adjusted to insert the reactive compensation rod downward.

[0019] Optionally, when the measured rod is located at the upper part of the core of the reactor, the first doubling period is a short period;

[0020] When the measured rod is located at the lower part of the core of the reactor, the first doubling period is a long period.

[0021] Optionally, the progressive cycle of the reactor is acquired by a source range device of a nuclear measurement system outside the reactor.

[0022] Optionally, first, the doubling period of the reactor is obtained according to the periodic table of the source range device; secondly, the progressive period of the reactor is calculated according to the doubling period.

[0023] Optionally, the neutron count rate of each channel of the source range is measured by the source range device, several groups of neutron count rate growth data are recorded, and the progressive cycle of the reactor is calculated based on the neutron count rate growth data.

[0024] Optionally, the power compensation rod is inserted downward and located at a preset low position, so that the neutron count rate of each channel of the reactor source range drops below a preset count rate.

[0025] Optionally, one of the first preset position and the second preset position is an upper limit position of the core of the reactor, and the other is located at a lower limit position of the core of the reactor.

[0026] One technical effect of the embodiment of the present application is:

[0027] In the embodiment of the present application, the method for measuring the reactivity value of the control rod of the high temperature gas-cooled reactor can accurately measure the reactivity value of the control rod, and has good operability. At the same time, it can reduce the research and development and equipment procurement costs of the reactivity instrument and reduce engineering investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flowchart of a method for measuring the reactivity value of a high temperature gas-cooled reactor control rod according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0030] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0031] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0033] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] like Figure 1 As shown, the embodiment of the present application provides a method for measuring the reactivity value of a control rod of a high temperature gas-cooled reactor, comprising the following steps:

[0035] Step S1, determine the measured rod, the reactivity compensation rod and the power compensation rod, so that the measured rod is located at a first preset position, the reactivity compensation rod is located at a second preset position, and the reactivity compensation rod is used to perform reactivity compensation on the measured rod; the power compensation rod is located at a preset high position to compensate for the power of the reactor.

[0036] Therefore, when measuring the reactivity value of the high temperature gas-cooled reactor control rod, it is necessary to first determine the rod positions of the measured rod, the reactivity compensation rod and the power compensation rod, so as to facilitate the subsequent accurate measurement of the reactivity value of the high temperature gas-cooled reactor control rod.

[0037] Step S2, starting the reactor, making the reactor reach and maintain a stable first doubling period; measuring the first doubling period, inserting the power compensation rod to control the power of the reactor.

[0038] Step S3, adjusting the position of the measured rod and lifting the power compensation rod, so that the reactor reaches and maintains a stable second doubling period; measuring the second doubling period, and inserting the power compensation rod to control the power of the reactor.

[0039] Step S4, adjusting the position of the reactive compensation rod and lifting the power compensation rod so that the reactor reaches and maintains a stable third multiplication cycle; measuring the third multiplication cycle, and inserting the power compensation rod to control the power of the reactor.

[0040] Step S5, repeating steps S3 to S4, obtaining each progressive cycle of the reactor according to each doubling cycle of the reactor, and calculating the reactivity value of the measured rod according to each progressive cycle of the reactor.

[0041] It should be noted that the reactivity value of the control rod of the high-temperature gas-cooled reactor can be measured by a dynamic measurement method, that is, it is determined by measuring the change law of the neutron flux or neutron density in the reactor over time. Among them, according to the characteristics of the high-temperature gas-cooled reactor itself, the dynamic measurement method adopted in this application is the progressive cycle method. Since the progressive cycle of the reactor and the reactivity value of the control rod are related by the reactivity equation, after the progressive cycle of the reactor is measured, the corresponding reactivity of the control rod can be calculated. Calculating the reactivity value of the control rod according to the progressive cycle of the reactor is relatively conventional and will not be introduced in detail here.

[0042] In the embodiment of the present application, the method for measuring the reactivity value of the control rod of the high temperature gas-cooled reactor can accurately measure the reactivity value of the control rod and has good operability.

[0043] Optionally, in step S1, one of the first preset position and the second preset position is at an upper part of a core of the reactor, and the other is at a lower part of the core of the reactor.

[0044] In the above embodiment, the positions of the measured rod and the reactivity compensation rod can be adjusted. Moreover, after adjusting the position of the measured rod, the reactivity value of the measured rod can be compensated by adjusting the position of the reactivity compensation rod, which is beneficial for the reactor to reach and maintain a stable doubling cycle.

[0045] Optionally, the measured rod is located at the upper part of the core of the reactor, and the reactive compensation rod is located at the lower part of the core of the reactor;

[0046] In step S3, the position of the measured rod is adjusted to insert the measured rod downward;

[0047] In step S4, adjusting the position of the reactive compensation rod is to lift the reactive compensation rod.

[0048] It should be noted that the reactivity value of the control rod measured each time by the progressive cycle method is relatively small, and the maximum reactivity value of the control rod cannot be measured by the progressive cycle method once. Therefore, in this application, according to the characteristics of the high-temperature gas-cooled reactor itself, segmented measurement is adopted, and after each segment of measurement is completed, compensation is performed by using a reactivity compensation rod with a smaller interference effect with the measured rod. After the segment-by-segment measurement is completed, the reactivity integral value of the measured rod is equal to the sum of the segment-by-segment measured reactivity values ​​of the rod to be measured, thereby achieving accurate measurement of the reactivity value of the control rod.

[0049] In the above embodiment, the position of the measured rod or the reactive compensation rod can be quickly adjusted, so as to realize accurate measurement of the doubling period of the reactor.

[0050] Optionally, the measured rod is located at the lower part of the core of the reactor, and the reactive compensation rod is located at the upper part of the core of the reactor;

[0051] In step S3, adjusting the position of the measured rod is to lift the measured rod;

[0052] In step S4, the position of the reactive compensation rod is adjusted to insert the reactive compensation rod downward.

[0053] In the above embodiment, the measured rod and the reactive compensating rod are adjusted accordingly according to their initial positions, which helps the reactor to reach and maintain a corresponding stable doubling cycle.

[0054] Optionally, when the measured rod is located at the upper part of the core of the reactor, the first doubling period is a short period;

[0055] When the measured rod is located at the lower part of the core of the reactor, the first doubling period is a long period.

[0056] In the above-mentioned implementation mode, the test data measured by the method for measuring the reactivity value of the control rod of the high temperature gas-cooled reactor can be verified whether it is consistent with the design value of the reactor, and the operability is good.

[0057] Optionally, the progressive cycle of the reactor is acquired by a source range device of a nuclear measurement system outside the reactor, which makes the measurement of the progressive cycle of the reactor very simple.

[0058] Optionally, first, the multiplication period of the reactor is obtained according to the periodic table of the source range device; secondly, the progressive period of the reactor is calculated according to the multiplication period. This can quickly calculate the progressive period of the reactor, thereby facilitating the rapid and accurate measurement of the reactivity value of the control rod of the high temperature gas-cooled reactor.

[0059] Optionally, the neutron count rate of each channel of the source range is measured by the source range device, several groups of neutron count rate growth data are recorded, and the progressive cycle of the reactor is calculated based on the neutron count rate growth data.

[0060] In the above implementation, the progressive cycle of the reactor can be calculated accurately and quickly, and the influence of data fluctuation on the calculation of the progressive cycle of the reactor can be effectively avoided.

[0061] It should be noted that the growth of the neutron pulse count rate is measured by the source range equipment of the nuclear measurement system, and the logarithm of the count rate is taken and fitted to calculate the reactor's progressive cycle. Therefore, in the actual test process, after the positive reactivity is introduced into the reactor, the neutron density in the reactor increases steadily, and the neutron count rate of each channel of the source range is measured at regular intervals to record several groups of neutron count rate growth data. The logarithm of the recorded data is calculated, and then the slope of the logarithmic neutron count rate growth over time is calculated through the slope function of Excel, and then the inverse of the slope is calculated to calculate the current reactor progressive cycle.

[0062] Optionally, the power compensation rod is inserted downward and placed at a preset low position, so that the neutron count rate of each channel of the reactor source range drops below a preset count rate. By adjusting the position of the power compensation rod, the power of the reactor can be effectively controlled, thereby facilitating the measurement of the reactivity value of the high temperature gas-cooled reactor control rod in different states.

[0063] Optionally, one of the first preset position and the second preset position is an upper limit position of the core of the reactor, and the other is located at a lower limit position of the core of the reactor.

[0064] In the above embodiment, it is convenient to adjust the positions of the measured rod and the reactive compensation rod in subsequent steps, and it is also convenient to accurately measure the progressive cycle of the reactor.

[0065] In a specific embodiment, the method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor comprises the following steps:

[0066] (1) Determine the measured rod, reactive compensation rod and power compensation rod, and adjust the positions of the three rods so that the measured rod is at the upper limit (or lower limit), the reactive compensation rod is at the lower limit (or upper limit), and the power compensation rod is at the specified higher position.

[0067] It should be noted that, if the initial position of the measured rod is the upper limit, the reactive compensation rod is at the lower limit; if the initial position of the measured rod is the lower limit, the reactive compensation rod is at the upper limit.

[0068] (2) By lifting the control rods other than the above three rods horizontally, the reactor can reach and maintain a shorter first doubling cycle (or a longer first doubling cycle).

[0069] It should be noted that the initial position of the measured rod is the upper limit, so that the reactor reaches and maintains a shorter first doubling period; the initial position of the measured rod is the lower limit, so that the reactor reaches and maintains a longer first doubling period.

[0070] (3) After the first doubling cycle of the reactor is stable, record the growth of the neutron count rate over time in the two source ranges, take the logarithm of the recorded neutron count rate data, and then use the slope function of Excel to calculate the slope of the logarithmic neutron count rate growth over time. Then, take the inverse of the slope to measure the first progressive cycle of the current reactor.

[0071] (4) Insert the power compensation rod down to a specified lower position so that the neutron count rate in the reactor source range drops below a certain count rate.

[0072] (5) When the measured rod is inserted (or lifted) to a certain rod position and maintained, and the power compensation rod is lifted to a higher position, the reactor will experience a longer doubling cycle (or a shorter doubling cycle).

[0073] It should be noted that if the initial position of the measured rod is the upper limit position, the measured rod will be inserted down a certain position in this step; if the initial position of the measured rod is the lower limit position, the measured rod will be lifted up a certain position in this step.

[0074] (6) Lifting the power compensation rods to a specified higher position so that the reactor can reach and maintain a longer second doubling cycle (or a shorter second doubling cycle).

[0075] It should be noted that if the initial position of the measured rod is the upper limit, this step will have a longer doubling period; it should be noted that if the initial position of the measured rod is the lower limit, this step will have a shorter doubling period.

[0076] (7) After the second doubling period of the reactor is stable, record the growth of the neutron count rate over time in the two source ranges, take the logarithm of the recorded neutron count rate data, and then use the slope function of Excel to calculate the slope of the logarithmic neutron count rate growth over time. Then, take the inverse of the slope to measure the second progressive period of the current reactor.

[0077] (8) Insert the power compensation rod down to a specified lower position so that the neutron count rate in the reactor source range drops below a certain count rate.

[0078] (9) Lifting (or inserting) the reactive compensating rod to a certain rod position and maintaining it so that the absolute value of the introduced reactivity is equivalent to the absolute value of the introduced reactivity in step (5).

[0079] It should be noted that if the initial position of the measured rod is the upper limit, the reactive compensation rod is lifted in this step; it should be noted that if the initial position of the measured rod is the lower limit, the reactive compensation rod is inserted in this step.

[0080] (10) Lift the power compensation rod to a specified higher position so that the reactor can reach and maintain a shorter third doubling cycle (or a longer third doubling cycle).

[0081] It should be noted that if the initial position of the measured rod is the upper limit, a shorter third doubling cycle occurs in this step; it should be noted that if the initial position of the measured rod is the lower limit, a longer third doubling cycle occurs in this step.

[0082] (11) After the third doubling period is stable, record the growth of the neutron count rate over time in the two source ranges, take the logarithm of the recorded neutron count rate data, and then use the slope function of Excel to calculate the slope of the logarithmic neutron count rate growth over time. Then, calculate the inverse of the slope to measure the current reactor progressive period.

[0083] (12) Insert the power compensation rod down to a specified lower position so that the neutron count rate in the reactor source range drops below a certain count rate.

[0084] (13) Repeat (5) to (12) until the reactivity value measurement of the entire measured rod is completed.

[0085] In summary, the method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor provided in the embodiment of the present application can very safely and accurately measure the reactivity value of control rods under a specific core state of a high-temperature gas-cooled reactor, and the measurement method is very simple.

[0086] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor, characterized in that: The steps include: Step S1, determining the measured rod, the reactive compensation rod and the power compensation rod, so that the measured rod is located at a first preset position, the reactive compensation rod is located at a second preset position, and the reactive compensation rod is used to perform reactive compensation on the measured rod; the power compensation rod is located at a preset high position; Step S2, starting the reactor, allowing the reactor to reach and maintain a stable first doubling period; measuring the first doubling period, and inserting the power compensation rod to control the power of the reactor; Step S3, adjusting the position of the measured rod and lifting the power compensation rod, so that the reactor reaches and maintains a stable second doubling period; measuring the second doubling period, and inserting the power compensation rod to control the power of the reactor; Step S4, adjusting the position of the reactive compensation rod and lifting the power compensation rod, so that the reactor reaches and maintains a stable third doubling period; measuring the third doubling period, and inserting the power compensation rod to control the power of the reactor; Step S5, repeating steps S3 to S4, obtaining each progressive cycle of the reactor according to each doubling cycle of the reactor, and calculating the reactivity value of the measured rod according to each progressive cycle of the reactor.

2. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 1, characterized in that: In step S1 , one of the first preset position and the second preset position is located at an upper portion of a core of the reactor, and the other is located at a lower portion of a core of the reactor.

3. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 2, characterized in that: The measured rod is located at the upper part of the core of the reactor, and the reactive compensation rod is located at the lower part of the core of the reactor; In step S3, the position of the measured rod is adjusted to insert the measured rod downward; In step S4, adjusting the position of the reactive compensation rod is to lift the reactive compensation rod.

4. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 2, characterized in that: The measured rod is located at the lower part of the core of the reactor, and the reactive compensation rod is located at the upper part of the core of the reactor; In step S3, adjusting the position of the measured rod is to lift the measured rod; In step S4, the position of the reactive compensation rod is adjusted to insert the reactive compensation rod downward.

5. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 2, characterized in that: When the measured rod is located at the upper part of the core of the reactor, the first doubling period is a short period; When the measured rod is located at the lower part of the core of the reactor, the first doubling period is a long period.

6. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 1, characterized in that: The progressive cycle of the reactor is acquired by a source range device of a nuclear measurement system outside the reactor.

7. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 6, characterized in that: Firstly, the doubling period of the reactor is obtained according to the periodic table of the source range device; secondly, the progressive period of the reactor is calculated according to the doubling period.

8. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 6, characterized in that: The source range device is used to measure the neutron count rate of each channel of the source range, and several groups of neutron count rate growth data are recorded. The progressive cycle of the reactor is calculated based on the neutron count rate growth data.

9. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 6, characterized in that: The power compensation rod is inserted downward and located at a preset low position, so that the neutron count rate of each channel of the reactor source range is reduced to below the preset count rate.

10. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 1, characterized in that: One of the first preset position and the second preset position is an upper limit position of the core of the reactor, and the other is located at a lower limit position of the core of the reactor.

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