CN-119915862-B - Doppler temperature coefficient determination method and device

CN119915862BCN 119915862 BCN119915862 BCN 119915862BCN-119915862-B

Abstract

The disclosure provides a method and a device for determining a Doppler temperature coefficient, and relates to the technical field of nuclear power. The method comprises the steps of controlling a moderator to change at a preset temperature change rate, enabling the temperature of fuel to change along with the temperature change of the moderator until the temperature of the fuel and the temperature of the moderator synchronously change at the temperature change rate, obtaining reactor core reactivity data of a nuclear reactor in the temperature change process, performing linear fitting on the reactor core reactivity data to obtain a reactivity change curve, determining a reactivity difference value between the reactor core reactivity data and the reactivity change curve at the initial control moment of temperature change and a temperature difference when the fuel and the moderator synchronously change, and determining the ratio of the reactivity difference value and the temperature difference as a Doppler temperature coefficient of the fuel. The method and the device obtain the Doppler temperature coefficient of the fuel by utilizing the temperature difference between the moderator and the fuel in the nuclear reactor and the reactivity difference of the reactor core reactivity data, do not need to depend on theoretical values or empirical values, and have higher coefficient accuracy while being convenient to operate.

Inventors

ZHANG SHENGBIN
CAO JINGTAO
Ding Quanbin
CAI SHU
CHEN YU
LI GUANJUN
ZHANG NANDI
JIA LONGFEI
YE HAIDENG
WENG CHAO
LIU YONG
WANG YUXUAN

Assignees

江西天红科技有限公司

Dates

Publication Date: 20260512
Application Date: 20241219

Claims (10)

1. A method of determining a doppler temperature coefficient, the method being applied to a nuclear reactor comprising a fuel and a moderator, the method comprising the steps of: Controlling the temperature of the moderator to change at a preset temperature change rate, wherein the temperature of the fuel changes along with the temperature change of the moderator, and when the temperature change time of the moderator exceeds a first time value, the temperature of the fuel and the temperature of the moderator synchronously change at the temperature change rate; Acquiring core reactivity data of the nuclear reactor in the temperature change process of the moderator; Performing linear fitting on the reactor core reactivity data to obtain a reactivity change curve; determining a reactivity difference between the core reactivity data and the reactivity change curve at an initial control time of temperature change; determining a temperature difference between the temperature of the fuel and the temperature of the moderator when the temperature changes synchronously at the temperature change rate according to the heat absorbed by the fuel per unit length according to the temperature change rate and a heat transfer equation; A ratio of the reactivity difference to the temperature difference is determined as a doppler temperature coefficient of the fuel.
2. The method of claim 1, wherein the amount of heat absorbed by the fuel per unit length according to the rate of temperature change is obtained by the formula: Φ=C*M*△t Wherein phi is the heat absorbed by the fuel per unit length according to the temperature change rate, C is the specific heat capacity of the fuel, M is the mass of the fuel per unit length, and Deltat is the temperature change rate.
3. The method according to claim 1 or 2, wherein the formula of the heat transfer equation is expressed as follows: Φ=K*A*△T 1 Wherein phi is the heat absorbed by the fuel per unit length according to the temperature change rate, K is a heat transfer coefficient, A is a heat exchange area, and DeltaT 1 is the temperature difference.
4. The method of claim 1, wherein the nuclear reactor is in a hot standby not-to-nuclear heating spot state.
5. A doppler temperature coefficient determination device for use in a nuclear reactor, the nuclear reactor including a fuel and a moderator, the device comprising: The temperature control module is used for controlling the temperature of the moderator to change at a preset temperature change rate, the temperature of the fuel changes along with the temperature change of the moderator, and when the temperature change time of the moderator exceeds a first time value, the temperature of the fuel and the temperature of the moderator synchronously change at the temperature change rate; The first acquisition module is used for acquiring reactor core reactivity data of the nuclear reactor in the temperature change process of the moderator; the second acquisition module is used for carrying out linear fitting on the reactor core reactivity data to obtain a reactivity change curve; a third acquisition module, configured to determine a reactivity difference between the core reactivity data and the reactivity change curve at an initial control time of a temperature change; A fourth acquisition module for determining a temperature difference between a temperature of the fuel and a temperature of the moderator when the temperature is synchronously changed at the temperature change rate according to a heat quantity absorbed by the fuel per unit length according to the temperature change rate and a heat transfer equation; a determination module for determining a ratio of the reactivity difference to the temperature difference as a doppler temperature coefficient of the fuel.
6. The apparatus of claim 5, wherein the fourth acquisition module is further configured to obtain the amount of heat absorbed by the fuel per unit length at the rate of temperature change by: Φ=C*M*△t Wherein phi is the heat absorbed by the fuel per unit length according to the temperature change rate, C is the specific heat capacity of the fuel, M is the mass of the fuel per unit length, and Deltat is the temperature change rate.
7. The apparatus of claim 5 or 6, wherein the heat transfer equation is formulated as follows: Φ=K*A*△T 1 Wherein phi is the heat absorbed by the fuel per unit length according to the temperature change rate, K is a heat transfer coefficient, A is a heat exchange area, and DeltaT 1 is the temperature difference.
8. The apparatus of claim 5, wherein the nuclear reactor is in a hot standby not-to-nuclear heating spot state.
9. An electronic device comprising a processor and a memory communicatively coupled to the processor; The memory stores computer-executable instructions; The processor executes computer-executable instructions stored in the memory to implement the method of any one of claims 1-4.
10. A computer readable storage medium having stored therein computer executable instructions which when executed by a processor are adapted to carry out the method of any one of claims 1-4.

Description

Doppler temperature coefficient determination method and device Technical Field The disclosure relates to the technical field of nuclear power, in particular to a method and a device for determining a Doppler temperature coefficient. Background The reactor reactivity change caused by the temperature coefficient change of the moderator at 1 ℃ is the temperature coefficient alpha mod of the moderator, the parameter is critical to the safety of the reactor, the requirement of being negative in the design process is required to be met, namely, the temperature rise of the moderator can introduce negative reactivity to cause the power reduction of the reactor, so that the self-stability of the reactor is realized. After the reactor is charged, the temperature coefficient of the moderator needs to be measured, the common practice is to change the temperature of the moderator and the fuel by breaking the heat balance of a two-loop before a nuclear heating point, the change of the reactivity in the temperature change process is measured by a reactivity meter, the ratio of the change quantity of the reactivity to the change quantity of the temperature is an isothermal temperature coefficient (the temperature coefficient of the moderator alpha mod +the Doppler temperature coefficient of the fuel alpha dop), and then the isothermal temperature coefficient is subtracted by the Doppler temperature coefficient of the fuel to obtain the temperature coefficient of the moderator. The change in reactor reactivity caused by the change in fuel temperature of 1 ℃ is the fuel Doppler temperature coefficient. Since the fuel temperature cannot be measured directly, the current fuel Doppler temperature coefficient is a theoretical value or an empirical value given by program calculation. The accuracy of this value directly affects the measured value of the moderator temperature coefficient and thus the safety of the reactor. Meanwhile, the inaccuracy of the fuel Doppler temperature coefficient can also lead to inaccurate physical-thermal coupling in the development process of a nuclear design program, so that the accuracy of program calculation is reduced. Disclosure of Invention The present disclosure aims to solve, at least to some extent, one of the technical problems in the related art. To this end, an embodiment of a first aspect of the present disclosure proposes a method of determining a doppler temperature coefficient, the method being applied to a nuclear reactor comprising a fuel and a moderator, the method comprising the steps of: Controlling the temperature of the moderator to change at a preset temperature change rate, wherein the temperature of the fuel changes along with the temperature change of the moderator, and when the temperature change time of the moderator exceeds a first time value, the temperature of the fuel and the temperature of the moderator synchronously change at the temperature change rate; Acquiring core reactivity data of the nuclear reactor in the temperature change process of the moderator; Performing linear fitting on the reactor core reactivity data to obtain a reactivity change curve; determining a reactivity difference between the core reactivity data and the reactivity change curve at an initial control time of temperature change; determining a temperature difference between the temperature of the fuel and the temperature of the moderator when the temperature changes synchronously at the temperature change rate according to the heat absorbed by the fuel per unit length according to the temperature change rate and a heat transfer equation; A ratio of the reactivity difference to the temperature difference is determined as a doppler temperature coefficient of the fuel. In some embodiments of the present disclosure, the amount of heat absorbed by the fuel per unit length according to the rate of temperature change is obtained by the following formula: Wherein, the Heat absorbed by the fuel per unit length in accordance with the temperature change rate,For the specific heat capacity of the fuel,Is the mass of fuel per unit length and,Is the rate of temperature change. In some embodiments of the present disclosure, the heat transfer equation is formulated as follows: Wherein, the Heat absorbed by the fuel per unit length in accordance with the temperature change rate,For the heat transfer coefficient,For the heat exchange area,Is the temperature difference. In some embodiments of the present disclosure, the nuclear reactor is in a hot standby not-to-nuclear heating spot state. In a second aspect, embodiments of the present disclosure provide a doppler temperature coefficient determination apparatus for use in a nuclear reactor, the nuclear reactor including a fuel and a moderator, the apparatus comprising: The temperature control module is used for controlling the temperature of the moderator to change at a preset temperature change rate, the temperature of the fuel changes along with the temper