CN105551551A - Low-power operation method of pool type sodium-cooled fast reactor needless of conventional island investment - Google Patents

Abstract

The invention relates to a low-power operation method of a pool type sodium-cooled fast reactor needless of conventional island investment, and belongs to the technology of pool type sodium-cooled fast reactor design. According to the method, the total normal heat radiation quantity of main and auxiliary systems of first and second loops is determined without investment of a third loop, and thus, the maximal power for long-term operation in a balanced state is determined. According to the total sodium loaded amount of the first and second loops and the initial starting temperature, the maximal power level and corresponding time relation of the reactor can be determined under highest temperature limit. Besides physical thermal calculation, control protection related setting values are modified correspondingly to satisfy the requirement for the safety allowance. On the premise that the safety allowance is ensured, the economical, reliable and flexible performances of the reactor are improved, the utilization rate of the reactor is effectively and fully improved, and corresponding scientific research level is improved.

Description

A kind of pool type natrium cold fast reactor low power run method not needing conventional island to drop into

Technical field

The invention belongs to pool type natrium cold fast reactor designing technique, be specifically related to a kind of pool type natrium cold fast reactor low power run method not needing conventional island to drop into.

Background technology

When pool type natrium cold fast reactor normally runs, the heat that reactor core produces is derived by main heat-transfer system (being made up of primary Ioops, secondary circuit, three loops) under normal circumstances, and is electric energy by Turbo-generator Set by thermal energy.Wherein three loops, comprise steam turbine and generator etc. and are all positioned at conventional island.China Experiment Fast Reactor (CEFR), as research reactor, is run in a lot of situation and carries out test under low-power, and now the equipment such as steam turbine does not reach service condition.Because conventional island equipment is many, complex operation, have the advantages that Meteorological is high, setup time is long, in the face of low-power can meet the situation of test demand, needing one badly can in middle low-power situation, do not drop into conventional island system equipment and the scheme run, to improve economy and dirigibility.

Conventional island is the normal downstream links running main heat-transfer system.When not using conventional island, need to consider that these heats are discharged by other approach, and determine that the parameters such as reactor temperature are no more than corresponding limit value.

Summary of the invention

The object of the invention is, meeting the prerequisite of nuclear safety and under not reducing the condition of safety allowance, providing a kind of pool type natrium cold fast reactor low power run method not needing conventional island to drop into, suitably to improve economy and reliability.

Technical scheme of the present invention is as follows: a kind of pool type natrium cold fast reactor low power run method not needing conventional island to drop into, comprises the steps:

(1) determine the heat removal capacity of reactor other system except main heat-transfer system, comprising:

(1-1) according to the flow of primary Ioops coolant cleanup system and the heat exhaust of cold-trap import and export differential thermal calculation primary Ioops coolant cleanup system;

(1-2) heat removal capacity of flow system flow and air cooler import and export differential thermal calculation accident afterheat discharge system is discharged according to accident afterheat;

(1-3) according to reactor pit ventilating system air quantity and the heat exhaust protecting container outer surface temperature computation reactor pit ventilating system;

(1-4) according to intermediate heat exchanger secondary side sodium gateway temperature difference, the heat exhaust of the major-minor system of secondary circuit is calculated;

(2) calculate temperature rise restriction according to reactor one, secondary circuit cooling medium thermal capacitance, comprising:

(2-1) determine one, secondary circuit cooling medium initial temperature;

(2-2) overall temperature rise rate is determined according to nuclear heating;

(3) when conventional island does not drop into, reactor low power run, reactor hoisting power is not more than 1% rated power, and monitoring intermediate heat exchanger primary side entrance sodium temperature is no more than 365 DEG C, maintains this interval different IPs power step and runs;

(4) according to the result of calculation of step (1), (2), and the test findings of step (3), the relevant setting valve of Control protection system is modified, to meet the requirement of safety allowance.

Further, do not need the pool type natrium cold fast reactor low power run method that conventional island drops into as above, in step (1-1), the heat exhaust formula calculating primary Ioops coolant cleanup system is as follows:

Q ₁＝G ₁(Hi-Ho)

Wherein:

Q ₁for primary Ioops cooling medium (sodium) cleaning system heat exhaust;

G ₁for flow;

H _ifor sodium entrance enthalpy;

H _ofor sodium returns enthalpy.

Further, do not need the pool type natrium cold fast reactor low power run method that conventional island drops into as above, in step (1-2), the heat removal capacity computation model that accident afterheat discharges system is as follows:

Heat transfer model in accident afterheat removal system intermediate loop pipeline:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_3{F}_3}{C_{Na}{V}_{Na}}(t_S-t_{Na})\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}(t_{Na}-t_S)+\frac{K_4{F}_4}{C_S{V}_S}(t_{B0}-t_S)\end{array}\right.$

Wherein:

τ-time, s;

T _na-coolant temperature, DEG C;

T _smedial temperature around-cooling medium in tube wall, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

The coordinate that Z-flows to along cooling medium, m;

U _na-coolant flow speed, m/s;

V _nacoolant volume in-unit length pipeline, m ³;

V _sthe volume of tube wall around cooling medium in-unit length pipeline, m ³;

K ₃-heat transfer coefficient from cooling medium to tube wall, W/m ²dEG C;

K ₄-heat transfer coefficient from tube wall to surrounding air, W/m ²dEG C;

F ₃heat exchange area on-unit length pipeline between cooling medium and tube wall, m ²;

F ₄heat exchange area between-unit length pipeline upper tube wall and surrounding air, m ²;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube walls around-cooling medium, J/m ³dEG C;

The heat transfer model of air cooler:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_1{F}_1}{C_{Na}{V}_{Na}}(t_S-t_{Na})\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_1{F}_1}{C_S{V}_S}(t_{Na}-t_S)+\frac{K_2{F}_2}{C_S{V}_S}(t_B-t_S)\\ \frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z^{*}}=\frac{K_2{F}_2}{C_B{V}_B}(t_S-t_B)+\frac{K_3{F}_3}{C_B{V}_B}(t_{SK}-t_B)\\ \frac{{\mathrm{dt}}_{SK}}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_{SK}{V}_{SK}}(t_B-t_{SK})+\frac{K_4{F}_4}{C_{SK}{V}_{SK}}(t_{BO}-t_{SK})\end{array}\right.$

Wherein:

T _nacoolant temperature in-air heat exchanger bundle, DEG C;

T _bair themperature in-air heat exchanger, DEG C;

T _sthe temperature of-air heat exchanger bundle metal, DEG C;

T _sK-consider the temperature of the air heat exchanger container of heat-insulation layer effect, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

Z-along the coordinate on air heat exchanger bundle length direction, m;

Z ^*-along the coordinate on space length direction between air heat exchanger bundle, m;

U _nasodium flowing velocity in-air heat exchanger bundle, m/s;

U _bspeed air flow in-air heat exchanger, m/s;

K ₁heat transfer coefficient between-sodium and air heat exchanger bundle, W/m ²dEG C;

K ₂the heat transfer coefficient of-tube bank and interbank air, W/m ²dEG C;

K ₃heat transfer coefficient between-air heat exchanger bundle between air and air heat exchanger container, W/m ²dEG C;

K ₄heat transfer (considering heat insulation layer) coefficient between-air heat exchanger container and surrounding air, W/m ²dEG C;

F ₁heat interchanging area in-unit length between sodium and air heat exchanger bundle, m ²;

F ₂the heat interchanging area of air heat exchanger pipeline and interbank air in-unit length, m ²;

F ₃heat interchanging area in-unit length between the interbank air of air heat exchanger and air heat exchanger container, m ²;

F ₄heat exchange area in-unit length between air heat exchanger container and surrounding air, m ²;

C _sthe active volume thermal capacitance of-air heat exchanger bundle, J/m ³dEG C;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sK-consider the average effective volumetric heat capacity of the air heat exchanger container of air heat exchanger bundle, J/m ³dEG C;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

V _nacoolant volume in-unit length in air heat exchanger bundle, m ³;

V _sthe volume of air heat exchanger bundle in-unit length, m ³;

V _bvolume of air between-air heat exchanger bundle in space in unit length, m ³;

V _sK-consider heat-insulation layer air heat exchanger container unit length on air heat exchanger volume of a container, m ³;

The fluid mechanic model of accident afterheat removal system intermediate loop:

Wherein:

τ-time, s;

-describe the vector of circuit units, m;

DP _l(τ)-unit on drive ram, Pa;

D ξ _l(τ)-unit on Flow Resistant Coefficient, relative unit;

ρ _l(τ)-unit on coolant density, kg/m ³;

-unit on coolant velocity, m/s;

-acceleration of gravity, m/s ²;

Accident afterheat removal system air flow channel heat exchange models:

$\left\{\begin{array}{c}\frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z}=\frac{K_3{F}_3}{C_B{V}_B}(t_S-t_B)\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}(t_B-t_S)+\frac{K_4{F}_4}{C_S{V}_S}(t_{B0}-t_S)\end{array}\right.$

Wherein:

τ-time, s;

T _bair themperature in-air flow channel, DEG C;

T _s-consider the temperature of the air flow channel of heat-insulation layer and xoncrete structure, DEG C;

T _bothe temperature of-air flow channel surrounding air, DEG C;

U _bthe air velocity of-air duct, m/s;

K ₃heat transfer coefficient in-air duct between air and tube wall, W/m ²dEG C;

K ₄heat transfer coefficient between-air duct and surrounding air, W/m ²dEG C;

F ₃heat interchanging area in-air duct unit length between air and pipeline, m ²;

F ₄heat interchanging area in-air duct unit length between pipeline and surrounding air, m ²;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube layer of-air duct, J/m ³dEG C;

V _bvolume of air in-air duct unit length, m ³;

V _sthe volume of the air duct structure in-air duct unit length, m ³;

Accident afterheat removal system air flow channel fluid mechanic model:

Wherein

τ-time, s;

-describe the vector of circuit units, m;

Δ P _windthe gas differential pressure of-formation on air flow channel population and outlet, Pa;

Δ P _wpressure reduction on (N, δ)-air heat exchanger export the breeze door, Pa;

The quantity of the blade on N-air heat exchanger export the breeze door, individual;

The corner of the blade on δ-air heat exchanger export the breeze door, degree;

D ξ _l(τ)-air flow channel unit on Flow Resistant Coefficient, relative unit;

ρ _l-air flow channel unit on coolant density, kg/m ³;

the unit of-air flow channel on coolant velocity, m/s;

-acceleration of gravity, m/s ².

Q ₂＝Q ₂₁+Q ₂₂(1-7)

Q ₂₁＝G ₂₁(H _21i-H _21o)(1-8)

Q ₂₁＝G ₂₂(H _22i-H _22o)(1-9)

Wherein:

Q ₂for accident afterheat removal system heat exhaust;

Q ₂₁for accident afterheat removal system I loop heat exhaust;

Q ₂₂for accident afterheat removal system II loop heat exhaust;

G ₂₁for accident afterheat removal system I loop traffic;

G ₂₂for accident afterheat removal system II loop traffic;

H _21ifor accident afterheat removal system I loop independent heat exchanger outlet temperature;

H _21ofor accident afterheat removal system I loop independent heat exchanger temperature in;

H _22ifor accident afterheat removal system II loop independent heat exchanger outlet temperature;

H _22ofor accident afterheat removal system II loop independent heat exchanger temperature in.

Further, do not need the pool type natrium cold fast reactor low power run method that conventional island drops into as above, in step (1-3), the computing formula of the heat exhaust of reactor pit ventilating system is as follows:

Q ₃＝G ₃(H _3o-H _3i)

Wherein:

Q ₃for reactor pit ventilating system heat exhaust;

G ₃for reactor pit ventilating system is through the ventilation of reactor pit;

H _3ifor reactor pit ventilating system intake air enthalpy;

H _3ofor reactor pit outlet of ventilating system air enthalpy.

Further, do not need the pool type natrium cold fast reactor low power run method that conventional island drops into as above, in step (1-4), the heat exhaust computing formula of the major-minor system of secondary circuit is as follows:

Q ₄＝Q ₄₁+Q ₄₂

Q ₄₁＝G ₄₁(H _41o-H _41i)

Q ₄₂＝G ₄₂(H _42o-H _42i)

Wherein:

Q ₄for the heat exhaust that the major-minor system of secondary circuit is total;

Q ₄₁for the heat exhaust that the major-minor system of secondary circuit I loop is total;

Q ₄₂for the heat exhaust that the major-minor system of secondary circuit II loop is total;

G ₄₁for secondary circuit I loop total flow;

G ₄₂for secondary circuit II loop total flow;

H _41ifor secondary circuit I loop intermediate heat exchanger entrance enthalpy;

H _41ofor secondary circuit I loop intermediate heat exchanger outlet enthalpy;

H _42ifor secondary circuit II loop intermediate heat exchanger entrance enthalpy;

H _42ofor secondary circuit II loop intermediate heat exchanger outlet enthalpy.

Further, do not need the pool type natrium cold fast reactor low power run method that conventional island drops into as above, in step (2-1), one, secondary circuit cooling medium initial temperature is 230-250 DEG C.

Further, the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as above, in step (2-2), according to the overall heat removal capacity of other system except main heat-transfer system, calculate the equilibrium point of nuclear heating and heat extraction, and according to one, the charging capacity of the total sodium of secondary circuit and corresponding specific heat capacity thereof, calculate maximum temperaturerise limit value and corresponding time relationship.

Beneficial effect of the present invention is as follows: the pool type natrium cold fast reactor low power run method not dropping into conventional island provided by the present invention, under the prerequisite ensureing security allowance, improve economy, reliability and dirigibility, and fully effectively can improve the utilization ratio of experimental reactor, improve the level of corresponding scientific research activity.

Accompanying drawing explanation

Fig. 1 is the normal operational flow diagram of China Experiment Fast Reactor of specific embodiment.

Figure comprises primary Ioops, secondary circuit and three loops in interior main heat-transfer system, and accident afterheat removal system is ad hoc in interior safety.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in detail.

The pool type natrium cold fast reactor low power run method not needing conventional island to drop into provided by the present invention, comprise when determining not drop into three loops, determine total one, the proper heat reduction amount of the major-minor system of secondary circuit, determining thus under equilibrium state can the peak power of long-time running.In addition, according to one, secondary circuit loads sodium total amount, according to initial starting temperature, can determine under the condition of maximum temperature limit value, the relation of the highest that reactor can run and corresponding time thereof.Therefore, except except physics thermodynamic metering, to the relevant setting valve of Control protection, carry out corresponding modify equally, meet the requirement of safety allowance.

The present embodiment is for the China Experiment Fast Reactor (CEFR) shown in Fig. 1, system equipment in Fig. 1 in double dot dash line, be the object that the present invention relates to, comprise the related system equipment such as Major Systems equipment and reactor pit ventilation of primary Ioops Major Systems equipment, secondary circuit Major Systems equipment, accident afterheat removal system.

Technical scheme of the present invention comprises calculating and reactor operation verification experimental verification two parts from composition, specifically comprises the following steps:

1. determine the heat removal capacity of reactor other system except main heat-transfer system

(1-1) according to the flow of primary Ioops coolant cleanup system and the heat exhaust of cold-trap import and export differential thermal calculation primary Ioops coolant cleanup system;

Primary Ioops sodium clean-up system is not formal heat-extraction system, but the heat that can shed during its work, there is certain heat removal capacity.The heat removal capacity (whether use interior economizer, strengthen oil cooling ability etc.) of this system can be increased, simultaneously by calculating the size determining this ability by changing the method for operation.

The heat exhaust formula calculating primary Ioops coolant cleanup system is as follows:

Q ₁＝G ₁(Hi-Ho)

Wherein:

Q ₁for primary Ioops cooling medium (sodium) cleaning system heat exhaust;

G ₁for flow;

H _ifor sodium entrance enthalpy;

H _ofor sodium returns enthalpy.

(1-2) heat removal capacity of flow system flow and air cooler import and export differential thermal calculation accident afterheat discharge system is discharged according to accident afterheat;

Get rid of reactor waste when accident afterheat system of discharging is used for main heat-transfer system fault, possess function equally when normal operation.This system derives heat by Natural Circulation, its heat removal capacity and reactor temperature correlation.Need when calculating reactor equilibrium temperature to carry out complicated iterative computation.

The heat removal capacity computation model that accident afterheat discharges system is as follows:

Heat transfer model in accident afterheat removal system intermediate loop pipeline:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_3{F}_3}{C_{Na}{V}_{Na}}(t_S-t_{Na})\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}(t_{Na}-t_S)+\frac{K_4{F}_4}{C_S{V}_S}(t_{B0}-t_S)\end{array}\right.$

Wherein:

τ-time, s;

T _na-coolant temperature, DEG C;

T _smedial temperature around-cooling medium in tube wall, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

The coordinate that Z-flows to along cooling medium, m;

U _na-coolant flow speed, m/s;

V _nacoolant volume in-unit length pipeline, m ³;

V _sthe volume of tube wall around cooling medium in-unit length pipeline, m ³;

K ₃-heat transfer coefficient from cooling medium to tube wall, W/m ²dEG C;

K ₄-heat transfer coefficient from tube wall to surrounding air, W/m ²dEG C;

F ₃heat exchange area on-unit length pipeline between cooling medium and tube wall, m ²;

F ₄heat exchange area between-unit length pipeline upper tube wall and surrounding air, m ²;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube walls around-cooling medium, J/m ³dEG C;

The heat transfer model of air cooler:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_1{F}_1}{C_{Na}{V}_{Na}}(t_S-t_{N2})\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_1{F}_1}{C_S{V}_S}(t_{Na}-t_S)+\frac{K_2{F}_2}{C_S{V}_S}(t_B-t_S)\\ \frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z^{*}}=\frac{K_2{F}_2}{C_B{V}_B}(t_S-t_B)+\frac{K_3{F}_3}{C_B{V}_B}(t_{SK}-t_B)\\ \frac{{\mathrm{dt}}_{SK}}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_{SK}{V}_{SK}}(t_B-t_{SK})+\frac{K_4{F}_4}{C_{SK}{V}_{SK}}(t_{BO}-t_{SK})\end{array}\right.$

Wherein:

T _nacoolant temperature in-air heat exchanger bundle, DEG C;

T _bair themperature in-air heat exchanger, DEG C;

T _sthe temperature of-air heat exchanger bundle metal, DEG C;

T _sK-consider the temperature of the air heat exchanger container of heat-insulation layer effect, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

Z-along the coordinate on air heat exchanger bundle length direction, m;

Z ^*-along the coordinate on space length direction between air heat exchanger bundle, m;

U _nasodium flowing velocity in-air heat exchanger bundle, m/s;

U _bspeed air flow in-air heat exchanger, m/s;

K ₁heat transfer coefficient between-sodium and air heat exchanger bundle, W/m ²dEG C;

K ₂the heat transfer coefficient of-tube bank and interbank air, W/m ²dEG C;

K ₃heat transfer coefficient between-air heat exchanger bundle between air and air heat exchanger container, W/m ²dEG C;

K ₄heat transfer (considering heat insulation layer) coefficient between-air heat exchanger container and surrounding air, W/m ²dEG C;

F ₁heat interchanging area in-unit length between sodium and air heat exchanger bundle, m ²;

F ₂the heat interchanging area of air heat exchanger pipeline and interbank air in-unit length, m ²;

F ₃heat interchanging area in-unit length between the interbank air of air heat exchanger and air heat exchanger container, m ²;

F ₄heat exchange area in-unit length between air heat exchanger container and surrounding air, m ²;

C _sthe active volume thermal capacitance of-air heat exchanger bundle, J/m ³dEG C;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sK-consider the average effective volumetric heat capacity of the air heat exchanger container of air heat exchanger bundle, J/m ³dEG C;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

V _nacoolant volume in-unit length in air heat exchanger bundle, m ³;

V _sthe volume of air heat exchanger bundle in-unit length, m ³;

V _bvolume of air between-air heat exchanger bundle in space in unit length, m ³;

V _sK-consider heat-insulation layer air heat exchanger container unit length on air heat exchanger volume of a container, m ³;

The fluid mechanic model of accident afterheat removal system intermediate loop:

Wherein:

τ-time, s;

-describe the vector of circuit units, m;

DP _l(τ)-unit on drive ram, Pa;

D ξ _l(τ)-unit on Flow Resistant Coefficient, relative unit;

ρ _l(τ)-unit on coolant density, kg/m ³;

-unit on coolant velocity, m/s;

-acceleration of gravity, m/s ²;

Accident afterheat removal system air flow channel heat exchange models:

$\left\{\begin{array}{c}\frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z}=\frac{K_3{F}_3}{C_B{V}_B}(t_S-t_B)\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}(t_B-t_S)+\frac{K_4{F}_4}{C_S{V}_S}(t_{B0}-t_S)\end{array}\right.$

Wherein:

τ-time, s;

T _bair themperature in-air flow channel, DEG C;

T _s-consider the temperature of the air flow channel of heat-insulation layer and xoncrete structure, DEG C;

T _bothe temperature of-air flow channel surrounding air, DEG C;

U _bthe air velocity of-air duct, m/s;

K ₃heat transfer coefficient in-air duct between air and tube wall, W/m ²dEG C;

K ₄heat transfer coefficient between-air duct and surrounding air, W/m ²dEG C;

F ₃heat interchanging area in-air duct unit length between air and pipeline, m ²;

F ₄heat interchanging area in-air duct unit length between pipeline and surrounding air, m ²;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube layer of-air duct, J/m ³dEG C;

V _bvolume of air in-air duct unit length, m ³;

V _sthe volume of the air duct structure in-air duct unit length, m ³;

Accident afterheat removal system air flow channel fluid mechanic model:

Wherein

τ-time, s;

-describe the vector of circuit units, m;

Δ P _windthe gas differential pressure of-formation on air flow channel population and outlet, Pa;

Δ P _wpressure reduction on (N, δ)-air heat exchanger export the breeze door, Pa;

The quantity of the blade on N-air heat exchanger export the breeze door, individual;

The corner of the blade on δ-air heat exchanger export the breeze door, degree;

D ξ _l(τ)-air flow channel unit on Flow Resistant Coefficient, relative unit;

ρ _l-air flow channel unit on coolant density, kg/m ³;

the unit of-air flow channel on coolant velocity, m/s;

-acceleration of gravity, m/s ².

Q ₂＝Q ₂₁+Q ₂₂(1-7)

Q ₂₁＝G ₂₁(H _21i-H _21o)(1-8)

Q ₂₁＝G ₂₂(H _22i-H _22o)(1-9)

Wherein:

Q ₂for accident afterheat removal system heat exhaust;

Q ₂₁for accident afterheat removal system I loop heat exhaust;

Q ₂₂for accident afterheat removal system II loop heat exhaust;

G ₂₁for accident afterheat removal system I loop traffic;

G ₂₂for accident afterheat removal system II loop traffic;

H _21ifor accident afterheat removal system I loop independent heat exchanger outlet temperature;

H _21ofor accident afterheat removal system I loop independent heat exchanger temperature in;

H _22ifor accident afterheat removal system II loop independent heat exchanger outlet temperature;

H _22ofor accident afterheat removal system II loop independent heat exchanger temperature in.

(1-3) according to reactor pit ventilating system air quantity and the heat exhaust protecting container outer surface temperature computation reactor pit ventilating system;

Reactor pit ventilating system, for cooling reactor pit, therefore inevitably takes the heat of reactor primary tank out of.Need simultaneous other factors to carry out complicated iterative computation when calculating reactor equilibrium temperature.

The computing formula of the heat exhaust of reactor pit ventilating system is as follows:

Q ₃＝G ₃(H _3o-H _3i)

Wherein:

Q ₃for reactor pit ventilating system heat exhaust;

G ₃for reactor pit ventilating system is through the ventilation of reactor pit;

H _3ifor reactor pit ventilating system intake air enthalpy;

H _3ofor reactor pit outlet of ventilating system air enthalpy.

(1-4) according to intermediate heat exchanger secondary side sodium gateway temperature difference, the heat exhaust of the major-minor system of secondary circuit is calculated;

By regulating secondary sodium revolution speed, secondary sodium cleaning system flow, secondary sodium to analyze detection system flow, the major-minor system electrical heating of secondary circuit etc., the regulable control that can carry out to a certain extent to secondary circuit heat exhaust.

The heat exhaust computing formula of the major-minor system of secondary circuit is as follows:

Q ₄＝Q ₄₁+Q ₄₂

Q ₄₁＝G ₄₁(H _41o-H _41i)

Q ₄₂＝G ₄₂(H _42o-H _42i)

Wherein:

Q ₄for the heat exhaust that the major-minor system of secondary circuit is total;

Q ₄₁for the heat exhaust that the major-minor system of secondary circuit I loop is total;

Q ₄₂for the heat exhaust that the major-minor system of secondary circuit II loop is total;

G ₄₁for secondary circuit I loop total flow;

G ₄₂for secondary circuit II loop total flow;

H _41ifor secondary circuit I loop intermediate heat exchanger entrance enthalpy;

H _41ofor secondary circuit I loop intermediate heat exchanger outlet enthalpy;

H _42ifor secondary circuit II loop intermediate heat exchanger entrance enthalpy;

H _42ofor secondary circuit II loop intermediate heat exchanger outlet enthalpy.

2. calculate temperature rise restriction according to reactor one, secondary circuit cooling medium thermal capacitance

(2-1) determine one, secondary circuit cooling medium initial temperature;

Under the actual cold shut state of current CEFR, one, the temperature of secondary sodium is between 230 ~ 250 DEG C, can regulate as required.

(2-2) overall temperature rise rate is determined according to nuclear heating;

By calculating the generation of heat and discharge, in conjunction with one, the thermal capacitance of secondary sodium, the speed that reactor temperature rises can be calculated.Obviously this speed is not constant.

The present invention is according to the overall heat removal capacity of other system except main heat-transfer system, the design parameter of association reaction heap, calculate the equilibrium point of nuclear heating and heat extraction, and according to one, the charging capacity of the total sodium of secondary circuit and corresponding specific heat capacity thereof, calculating maximum temperaturerise limit value and corresponding time relationship.The principle of described calculating and concrete computing method are the ordinary skill in the art.

3. reactor low power run

When conventional island does not drop into, reactor low power run, reactor hoisting power is not more than 1% rated power, and monitoring intermediate heat exchanger primary side entrance sodium temperature is no more than 365 DEG C, maintains this interval different IPs power step and runs

4. according to result of calculation and the test findings of above-mentioned steps, the relevant setting valve of Control protection system is modified, to meet the requirement of safety allowance.Under low-power, under the condition meeting safety limit, amendment part protection seting value, promotes safety allowance, such as power-level safety setting, core exit sodium temperature, and one, secondary circuit sodium pump controls to interlock.

China Experiment Fast Reactor is when power is less than 10%, and power-level safety setting is 11%, and this value, when not putting into operation in three loops, for actual motion power, must adjust accordingly.In addition, the protection value of core exit sodium temperature, the relevant protection seting value such as period protection; all according to the actual requirements, stricter restriction to be carried out, in necessary situation; increase part interlock protection, such as one, the control interlocking, intermediate heat exchanger gateway sodium temperature protection seting value etc. of secondary circuit sodium pump.

China Experiment Fast Reactor carries out low power run in this way, and parameters meets Technical specification requirement.Further, operating standard can be formulated according to the method, for common operations staff according to guidelines.

Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if belong within the scope of the claims in the present invention and equivalent technology thereof to these amendments of the present invention and modification, then the present invention is also intended to comprise these change and modification.

Claims (7)

1. do not need the pool type natrium cold fast reactor low power run method that conventional island drops into, comprise the steps:

(1) determine the heat removal capacity of reactor other system except main heat-transfer system, comprising:

(1-1) according to the flow of primary Ioops coolant cleanup system and the heat exhaust of cold-trap import and export differential thermal calculation primary Ioops coolant cleanup system;

(1-2) heat removal capacity of flow system flow and air cooler import and export differential thermal calculation accident afterheat discharge system is discharged according to accident afterheat;

(1-3) according to reactor pit ventilating system air quantity and the heat exhaust protecting container outer surface temperature computation reactor pit ventilating system;

(1-4) according to intermediate heat exchanger secondary side sodium gateway temperature difference, the heat exhaust of the major-minor system of secondary circuit is calculated;

(2) calculate temperature rise restriction according to reactor one, secondary circuit cooling medium thermal capacitance, comprising:

(2-1) determine one, secondary circuit cooling medium initial temperature;

(2-2) overall temperature rise rate is determined according to nuclear heating;

(3) when conventional island does not drop into, reactor low power run, reactor hoisting power is not more than 1% rated power, and monitoring intermediate heat exchanger primary side entrance sodium temperature is no more than 365 DEG C, maintains this interval different IPs power step and runs;

(4) according to the result of calculation of step (1), (2), and the test findings of step (3), the relevant setting valve of Control protection system is modified, to meet the requirement of safety allowance.

2. the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as claimed in claim 1, is characterized in that: in step (1-1), and the heat exhaust formula calculating primary Ioops coolant cleanup system is as follows:

Q ₁＝G ₁(Hi-Ho)

Wherein:

Q ₁for primary Ioops coolant cleanup system heat exhaust;

G ₁for flow;

H _ifor sodium entrance enthalpy;

H _ofor sodium returns enthalpy.

3. the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as claimed in claim 1, is characterized in that: in step (1-2), and the heat removal capacity computation model that accident afterheat discharges system is as follows:

Heat transfer model in accident afterheat removal system intermediate loop pipeline:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_3{F}_3}{C_{Na}{V}_{Na}}\left(t_S-t_{Na}\right)\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}\left(t_{Na}-t_S\right)+\frac{K_4{F}_4}{C_S{V}_S}\left(t_{B0}-t_S\right)\end{array}\right.$

Wherein:

τ-time, s;

T _na-coolant temperature, DEG C;

T _smedial temperature around-cooling medium in tube wall, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

The coordinate that Z-flows to along cooling medium, m;

U _na-coolant flow speed, m/s;

V _nacoolant volume in-unit length pipeline, m ³;

V _sthe volume of tube wall around cooling medium in-unit length pipeline, m ³;

K ₃-heat transfer coefficient from cooling medium to tube wall, W/m ²dEG C;

K ₄-heat transfer coefficient from tube wall to surrounding air, W/m ²dEG C;

F ₃heat exchange area on-unit length pipeline between cooling medium and tube wall, m ²;

F ₄heat exchange area between-unit length pipeline upper tube wall and surrounding air, m ²;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube walls around-cooling medium, J/m ³dEG C;

The heat transfer model of air cooler:

$\left\{\begin{array}{c}\frac{\∂t_{Na}}{\∂\mathrm{\τ}}+u_{Na}\frac{\∂t_{Na}}{\∂z}=\frac{K_1{F}_1}{C_{Na}{V}_{Na}}\left(t_S-t_{Na}\right)\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_1{F}_1}{C_S{V}_S}\left(t_{Na}-t_S\right)+\frac{K_2{F}_2}{C_S{V}_S}\left(t_B-t_S\right)\\ \frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z^{*}}=\frac{K_2{F}_2}{C_B{V}_B}\left(t_S-t_B\right)+\frac{K_3{F}_3}{C_B{V}_B}\left(t_{SK}-t_B\right)\\ \frac{{\mathrm{dt}}_{SK}}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_{SK}{V}_{SK}}\left(t_B-t_{SK}\right)+\frac{K_4{F}_4}{C_{SK}{V}_{SK}}\left(t_{BO}-t_{SK}\right)\end{array}\right.$

Wherein:

T _nacoolant temperature in-air heat exchanger bundle, DEG C;

T _bair themperature in-air heat exchanger, DEG C;

T _sthe temperature of-air heat exchanger bundle metal, DEG C;

T _sK-consider the temperature of the air heat exchanger container of heat-insulation layer effect, DEG C;

T _b0-tube wall ambient air temperature, DEG C;

Z-along the coordinate on air heat exchanger bundle length direction, m;

Z ^*-along the coordinate on space length direction between air heat exchanger bundle, m;

U _nasodium flowing velocity in-air heat exchanger bundle, m/s;

U _bspeed air flow in-air heat exchanger, m/s;

K ₁heat transfer coefficient between-sodium and air heat exchanger bundle, W/m ²dEG C;

K ₂the heat transfer coefficient of-tube bank and interbank air, W/m ²dEG C;

K ₃heat transfer coefficient between-air heat exchanger bundle between air and air heat exchanger container, W/m ²dEG C;

K ₄heat transfer (considering heat insulation layer) coefficient between-air heat exchanger container and surrounding air, W/m ²dEG C;

F ₁heat interchanging area in-unit length between sodium and air heat exchanger bundle, m ²;

F ₂the heat interchanging area of air heat exchanger pipeline and interbank air in-unit length, m ²;

F ₃heat interchanging area in-unit length between the interbank air of air heat exchanger and air heat exchanger container, m ²;

F ₄heat exchange area in-unit length between air heat exchanger container and surrounding air, m ²;

C _sthe active volume thermal capacitance of-air heat exchanger bundle, J/m ³dEG C;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sK-consider the average effective volumetric heat capacity of the air heat exchanger container of air heat exchanger bundle, J/m ³dEG C;

C _na-coolant volume thermal capacitance, J/m ³dEG C;

V _nacoolant volume in-unit length in air heat exchanger bundle, m ³;

V _sthe volume of air heat exchanger bundle in-unit length, m ³;

V _bvolume of air between-air heat exchanger bundle in space in unit length, m ³;

V _sK-consider heat-insulation layer air heat exchanger container unit length on air heat exchanger volume of a container, m ³;

The fluid mechanic model of accident afterheat removal system intermediate loop:

wherein:

τ-time, s;

-describe the vector of circuit units, m;

DP _l(τ)-unit on drive ram, Pa;

D ξ _l(τ)-unit on Flow Resistant Coefficient, relative unit;

ρ _l(τ)-unit on coolant density, kg/m ³;

-unit on coolant velocity, m/s;

-acceleration of gravity, m/s ²;

Accident afterheat removal system air flow channel heat exchange models:

$\left\{\begin{array}{c}\frac{\∂t_B}{\∂\mathrm{\τ}}+u_B\frac{\∂t_B}{\∂z}=\frac{K_3{F}_3}{C_B{V}_B}\left(t_S-t_B\right)\\ \frac{{\mathrm{dt}}_S}{d\mathrm{\τ}}=\frac{K_3{F}_3}{C_S{V}_S}\left(t_B-t_S\right)+\frac{K_4{F}_4}{C_S{V}_S}\left(t_{B0}-t_S\right)\end{array}\right.$

Wherein:

τ-time, s;

T _bair themperature in-air flow channel, DEG C;

T _s-consider the temperature of the air flow channel of heat-insulation layer and xoncrete structure, DEG C;

T _bothe temperature of-air flow channel surrounding air, DEG C;

U _bthe air velocity of-air duct, m/s;

K ₃heat transfer coefficient in-air duct between air and tube wall, W/m ²dEG C;

K ₄heat transfer coefficient between-air duct and surrounding air, W/m ²dEG C;

F ₃heat interchanging area in-air duct unit length between air and pipeline, m ²;

F ₄heat interchanging area in-air duct unit length between pipeline and surrounding air, m ²;

C _b-volume of air thermal capacitance, J/m ³dEG C;

C _sthe average effective volumetric heat capacity of all tube layer of-air duct, J/m ³dEG C;

V _bvolume of air in-air duct unit length, m ³;

V _sthe volume of the air duct structure in-air duct unit length, m ³;

Accident afterheat removal system air flow channel fluid mechanic model:

Wherein

τ-time, s;

-describe the vector of circuit units, m;

Δ P _windthe gas differential pressure of-formation on air flow channel population and outlet, Pa;

Δ P _wpressure reduction on (N, δ)-air heat exchanger export the breeze door, Pa;

The quantity of the blade on N-air heat exchanger export the breeze door, individual;

The corner of the blade on δ-air heat exchanger export the breeze door, degree;

D ξ _l(τ)-air flow channel unit on Flow Resistant Coefficient, relative unit;

ρ _l-air flow channel unit on coolant density, kg/m ³;

the unit of-air flow channel on coolant velocity, m/s;

-acceleration of gravity, m/s ².

Q ₂＝Q ₂₁+Q ₂₂(1-7)

Q ₂₁＝G ₂₁(H _21i-H _21o)(1-8)

Q ₂₁＝G ₂₂(H _22i-H _22o)(1-9)

Wherein:

Q ₂for accident afterheat removal system heat exhaust;

Q ₂₁for accident afterheat removal system I loop heat exhaust;

Q ₂₂for accident afterheat removal system II loop heat exhaust;

G ₂₁for accident afterheat removal system I loop traffic;

G ₂₂for accident afterheat removal system II loop traffic;

H _21ifor accident afterheat removal system I loop independent heat exchanger outlet temperature;

H _21ofor accident afterheat removal system I loop independent heat exchanger temperature in;

H _22ifor accident afterheat removal system II loop independent heat exchanger outlet temperature;

H _22ofor accident afterheat removal system II loop independent heat exchanger temperature in.

4. the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as claimed in claim 1, is characterized in that: in step (1-3), the computing formula of the heat exhaust of reactor pit ventilating system is as follows:

Q ₃＝G ₃(H _3o-H _3i)

Wherein:

Q ₃for reactor pit ventilating system heat exhaust;

G ₃for reactor pit ventilating system is through the ventilation of reactor pit;

H _3ifor reactor pit ventilating system intake air enthalpy;

H _3ofor reactor pit outlet of ventilating system air enthalpy.

5. the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as claimed in claim 1, it is characterized in that: in step (1-4), the heat exhaust computing formula of the major-minor system of secondary circuit is as follows:

Q ₄＝Q ₄₁+Q ₄₂

Q ₄₁＝G ₄₁(H _41o-H _41i)

Q ₄₂＝G ₄₂(H _42o-H _42i)

Wherein:

Q ₄for the heat exhaust that the major-minor system of secondary circuit is total;

Q ₄₁for the heat exhaust that the major-minor system of secondary circuit I loop is total;

Q ₄₂for the heat exhaust that the major-minor system of secondary circuit II loop is total;

G ₄₁for secondary circuit I loop total flow;

G ₄₂for secondary circuit II loop total flow;

H _41ifor secondary circuit I loop intermediate heat exchanger entrance enthalpy;

H _41ofor secondary circuit I loop intermediate heat exchanger outlet enthalpy;

H _42ifor secondary circuit II loop intermediate heat exchanger entrance enthalpy;

H _42ofor secondary circuit II loop intermediate heat exchanger outlet enthalpy.

6. the pool type natrium cold fast reactor low power run method as claimed in claim 1 not needing conventional island to drop into, is characterized in that: in step (2-1), one, secondary circuit cooling medium initial temperature is 230-250 DEG C.

7. the pool type natrium cold fast reactor low power run method not needing conventional island to drop into as claimed in claim 1, it is characterized in that: in step (2-2), according to the overall heat removal capacity of other system except main heat-transfer system, calculate the equilibrium point of nuclear heating and heat extraction, and according to one, the charging capacity of the total sodium of secondary circuit and corresponding specific heat capacity thereof, calculate maximum temperaturerise limit value and corresponding time relationship.