Method for measuring the isothermal temperature coefficient of a high temperature gas cooled reactor core

Abstract

The application discloses a kind of high temperature gas cooled reactor core isothermal temperature coefficient measurement method, comprising the following steps: 1) drawing the temperature-reactivity fitting curve in the temperature rising section range of primary loop, the slope of temperature-reactivity fitting curve at B ℃ is high temperature gas cooled reactor isothermal temperature coefficient α (T) 上升 ; 2) drawing the temperature-reactivity fitting curve in the temperature falling section range of primary loop, the slope of temperature-reactivity fitting curve at B ℃ is high temperature gas cooled reactor isothermal temperature coefficient α (T) 下降 ; 3) the calculation B ℃ at high temperature gas cooled reactor core isothermal temperature coefficient α (T) = [α (T) 上升 + α (T) 下降 ] / 2, the method can accurately measure the isothermal temperature coefficient of high temperature gas cooled reactor core.

Description

Technical Field

[0001] The invention belongs to the field of nuclear reactor core physical tests and relates to a method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core. Background Art

[0002] The high-temperature gas-cooled reactor nuclear power unit is an advanced reactor type with the characteristics of fourth-generation nuclear power technology and is one of the main reactor types in the development of nuclear power today. Its most important feature is its very large heat capacity and good core negative temperature reactivity coefficient, which are the inherent safety characteristics of the high-temperature gas-cooled reactor.

[0003] In the disclosed invention CN201811602298.8, the primary circuit temperature of the pressurized water reactor nuclear power unit is T ref The isothermal temperature coefficient is obtained by adjusting the linear segment by ±1°C. The disclosed invention CN201611052690.0 uses a correction method to compensate for the control rod position and critical boron concentration, which can obtain relatively satisfactory results.

[0004] Since high-temperature gas-cooled reactors use graphite as a moderator and helium as a coolant, the coolant does not contain soluble poison boron. In addition, the high-temperature gas-cooled reactor has a large heat capacity, and the coolant helium and heat transfer rate are much slower than those of pressurized water reactors or liquid metal-cooled fast reactors. Therefore, the isothermal temperature coefficient measurement method used in pressurized water reactors or liquid metal-cooled fast reactors is not applicable to high-temperature gas-cooled reactors, and will result in large measurement errors. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core, which can accurately measure the isothermal temperature coefficient of a high-temperature gas-cooled reactor core.

[0006] To achieve the above object, the method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core according to the present invention comprises the following steps:

[0007] 1) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature rise, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 上升 ;

[0008] 2) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature drop, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 下降 ;

[0009] 3) Calculate the isothermal temperature coefficient of the high temperature gas-cooled reactor core at B℃ α(T) = [α(T) 上升 +α(T) 下降 ] / 2.

[0010] The specific steps include:

[0011] 11) Carry out preliminary preparations;

[0012] 12) Heat the primary circuit to A°C, stop heating the primary circuit, and after the main helium blower has been running stably at full speed for more than N minutes at this temperature, record the reactivity at this temperature;

[0013] 13) Re-start the heating of the first circuit. After the temperature of the first circuit rises by ΔT℃, stop heating the first circuit and keep the temperature of the first circuit stable.

[0014] 14) After waiting for more than N minutes, record the reactivity at the current temperature;

[0015] 15) Repeat steps 13) to 14) until the primary circuit temperature reaches C°C;

[0016] 16) Draw the temperature-reactivity fitting curve within the temperature rise range of the primary circuit, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 上升 , where A<B<C;

[0017] 17) The main helium blower operates at a reduced frequency to gradually cool down the primary circuit;

[0018] 18) After the primary circuit temperature drops by ΔT°C, remove the water-cooled wall to keep the primary circuit temperature stable;

[0019] 19) After the temperature remains stable for more than N minutes, record the reactivity at the current temperature;

[0020] 110) Repeat steps 17) to 19) until the primary circuit temperature drops to A°C;

[0021] 111) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature drop, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 下降 ;

[0022] 112) Calculate the difference Δα = α(T) 上升 -α(T) 下降 ;

[0023] 113) Repeat steps 11) to 112) until |Δα| ≤ a preset value;

[0024] 116) Calculate the isothermal temperature coefficient of the high temperature gas-cooled reactor core at B℃ α(T) = [α(T) 上升 +α(T) 下降 ] / 2.

[0025] B=250; C=260; A=240.

[0026] The value range of ΔT is 1 to 2°C.

[0027] The specific process of step 11) is:

[0028] 11a) Place all the absorbent balls on top of the reactor;

[0029] 11b) Place the control rods at the critical rod position;

[0030] 11c) The reactor power is maintained below the nuclear heating point;

[0031] 11d) The reactivity meter has been put into use to monitor reactivity;

[0032] 11e) The main helium blower runs stably at full speed and the primary heating circuit is put into operation.

[0033] In step 17), a water-cooled wall or a waste heat removal system is used to gradually cool down the primary circuit.

[0034] N=30.

[0035] The default value is 2pcm / ℃.

[0036] The present invention has the following beneficial effects:

[0037] In the specific operation of the method for measuring the isothermal temperature coefficient of the high-temperature gas-cooled reactor core of the present invention, the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor core is 上升 and the isothermal temperature coefficient α(T) of the high temperature gas-cooled reactor 下降 The isothermal temperature coefficient of the HTGR core at B℃ is calculated to avoid the measurement error caused by the large heat capacity buffer of the HTGR, thereby obtaining a more accurate isothermal temperature coefficient. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0039] The method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core according to the present invention comprises the following steps:

[0040] 1) Place all the absorbent balls on top of the reactor;

[0041] 2) Place the control rod at the critical rod position;

[0042] 3) The reactor power is maintained below the nuclear heating point (POAH point);

[0043] 4) Reactivity instrument has been put into use to monitor reactivity;

[0044] 5) The main helium blower runs stably at full speed, and the primary heating circuit is put into operation;

[0045] 6) Heat the primary circuit to 240°C, stop heating the primary circuit, and run the main helium blower stably at full speed for more than 30 minutes at this temperature. Record the reactivity at this temperature.

[0046] 7) Re-start the heating of the first circuit. After the temperature of the first circuit rises by ΔT℃, stop heating the first circuit and keep the temperature of the first circuit stable.

[0047] 8) After waiting for more than 30 minutes, record the reactivity at the current temperature;

[0048] 9) Repeat steps 7) to 8) until the primary circuit temperature reaches 260°C;

[0049] 10) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature rise, and take the slope of the temperature-reactivity fitting curve at 250°C as the isothermal temperature coefficient α(T) rise of the high-temperature gas-cooled reactor;

[0050] 11) The main helium blower operates at a reduced frequency, and the water-cooled wall is used or the waste heat is removed from the system to gradually cool down the primary circuit;

[0051] 12) After the primary circuit temperature drops by ΔT°C, remove the water-cooled wall to keep the primary circuit temperature stable;

[0052] 13) After the temperature remains stable for more than 30 minutes, record the reactivity at the current temperature;

[0053] 14) Repeat steps 11) to 13) until the primary circuit temperature drops to 240°C;

[0054] 15) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature drop, and take the slope of the temperature-reactivity fitting curve at 250°C as the isothermal temperature coefficient α(T) drop of the high-temperature gas-cooled reactor;

[0055] 16) Calculate the difference Δα = α(T) 上升 -α(T) 下降 ;

[0056] 17) Repeat steps 5) to 16) until |Δα|≤2pcm / °C;

[0057] 18) Calculate the isothermal temperature coefficient α(T) at 250°C, where the isothermal temperature coefficient at 250°C is the average of the isothermal temperature coefficients of the temperature rising section and the temperature falling section at 250°C, that is, α(T) = [α(T) 上升 +α(T) 下降 ] / 2.

[0058] Among them, the value range of ΔT is 1 to 2°C;

[0059] It should be noted that the method for obtaining the isothermal temperature coefficient at other temperatures of the high-temperature gas-cooled reactor is similar.

[0060] To address the large thermal capacity and thermal inertia of the high-temperature gas-cooled reactor core, the present invention raises the temperature of a circuit over a wide range and measures the reactivity corresponding to each temperature step. This method then obtains a temperature-reactivity fitting curve within a certain temperature range. Based on the slope of the fitting curve at a specific temperature, the isothermal temperature coefficient for the rising edge corresponding to that temperature is determined. A similar cooling operation is performed to obtain the isothermal temperature coefficient for the falling edge. This process is repeated until the difference between the two isothermal temperature coefficients is ≤2pcm / °C; the final isothermal temperature coefficient is the average of the isothermal temperature coefficients for the rising and falling edges.

Claims

1. A method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core, characterized in that: The following steps are involved: 1) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature rise, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 上升 ; 2) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature drop, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 下降 ; 3) Calculate the isothermal temperature coefficient of the high temperature gas-cooled reactor core at B℃ α(T) = [α(T) 上升 +α(T) 下降 ] / 2; The specific steps include: 11) Carry out preliminary preparations; 12) Heat the primary circuit to A°C, stop heating the primary circuit, and after the main helium blower has been running stably at full speed for more than N minutes at A°C, record the reactivity at A°C; 13) Re-start the heating of the first circuit. After the temperature of the first circuit rises by ΔT℃, stop heating the first circuit and keep the temperature of the first circuit stable. 14) After waiting for more than N minutes, record the reactivity at the current temperature; 15) Repeat steps 13) to 14) until the primary circuit temperature reaches C°C; 16) Draw the temperature-reactivity fitting curve within the temperature rise range of the primary circuit, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 上升 , where A<B<C; 17) The main helium blower operates at a reduced frequency to gradually cool down the primary circuit; 18) After the primary circuit temperature drops by ΔT°C, remove the water-cooled wall to keep the primary circuit temperature stable; 19) After the primary circuit temperature remains stable for more than N minutes, record the reactivity at the current temperature; 110) Repeat steps 17) to 19) until the primary circuit temperature drops to A°C; 111) Draw the temperature-reactivity fitting curve within the range of the primary circuit temperature drop, and use the slope of the temperature-reactivity fitting curve at B℃ as the isothermal temperature coefficient α(T) of the high-temperature gas-cooled reactor. 下降 ; 112) Calculate the difference Δα = α(T) 上升 -α(T) 下降 ; 113) Repeat steps 11) to 112) until |Δα| ≤ a preset value; 116) Calculate the isothermal temperature coefficient of the high temperature gas-cooled reactor core at B℃ α(T) = [α(T) 上升 +α(T) 下降 ] / 2.

2. The method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core according to claim 1, characterized in that: B=250; C=260; A=240.

3. The method for measuring the isothermal temperature coefficient of a high-temperature gas-cooled reactor core according to claim 1, characterized in that: The value range of ΔT is 1 to 2°C.

4. The method for measuring the isothermal temperature coefficient of a high temperature gas-cooled reactor core according to claim 1, characterized in that: The specific process of step 11) is: 11a) Place all the absorbent balls on top of the reactor; 11b) Place the control rods at the critical rod position; 11c) The reactor power is maintained below the nuclear heating point; 11d) The reactivity meter has been put into use to monitor reactivity; 11e) The main helium blower runs stably at full speed and the primary heating circuit is put into operation.

5. The method for measuring the isothermal temperature coefficient of a high temperature gas-cooled reactor core according to claim 1, characterized in that: In step 17), a water-cooled wall or waste heat removal system is used to gradually cool down the primary circuit.

6. The method for measuring the isothermal temperature coefficient of a high temperature gas-cooled reactor core according to claim 1, characterized in that: N＝30。 7. The method for measuring the isothermal temperature coefficient of a high temperature gas-cooled reactor core according to claim 1, characterized in that: The default value is 2pcm / ℃.