A method for determining rated thermal output test of nuclear power units

Abstract

The present invention relates to the technical field of nuclear power operation, and specifically discloses a method for determining a rated heat output test of a nuclear power unit, comprising the following steps: step one: setting the unit state; isolating the corresponding system according to the test requirements, and determining the state of the unit during the test; step two: heat balance calculation; according to the heat balance calculation requirements of the nuclear steam supply system, calculating the primary circuit heat power N of the unit at this time through the secondary circuit parameters. 计算 , and record the relevant parameters by directly reading or searching the relevant files and curves; Step 3: Calculate the test judgment parameters; Calculate the thermal power percentage k 热 , Main water flow percentage k 给水 , actual steam volume flow percentage k 蒸汽 , steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 ; Step 4: Rated heat output test determination. The method of the present invention takes into account whether the secondary circuit has the ability to do work to remove the heat of the primary circuit, and the determination method is more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power operation, and in particular relates to a method for determining a rated heat output test of a nuclear power unit. Background Art

[0002] The rated heat output test of a nuclear power plant is an important test during the unit commissioning phase, which is used to verify whether the reactor's ability to supply heat to the secondary circuit can meet the design requirements. At the same time, this test is also included in the commissioning test outline.

[0003] The current test method for rated heat output in the industry mainly adopts the method of heat balance calculation, that is, the actual heat output of the first circuit is measured through the second circuit, and compared with the actual design value to determine whether the rated heat output can meet the design requirements. However, due to the particularity of nuclear power units, it is not allowed to operate at 100% thermal power during the operation of the unit, and a certain thermal power margin should be left to ensure the safety of the unit.

[0004] Therefore, in actual tests, the heat output of a circuit measured by thermal balance is less than the rated heat output value. Therefore, there are two main methods for current test acceptance judgment:

[0005] 1. Use the percentage and power measured by the nuclear instrument system to correct the measured thermal output power. Compare the corrected thermal output power with the rated power. If it is greater than or equal to the rated power, the test is qualified;

[0006] 2. The calculated thermal power is qualified within the range of ±1% of the actual design rated thermal power, but it is necessary to monitor whether the steam generator outlet pressure meets the requirements (considering the instrument error, the steam generator outlet pressure generally needs to be greater than 99.5% of the rated pressure).

[0007] For the above two test judgment methods, the correction method used in method 1 does not meet the requirements in principle, because the value displayed by the nuclear power instrument is determined by the ratio of the actual value of the thermal power measured by the heat balance to the designed rated thermal output, and its reverse correction can no longer be used; the judgment method of method 2 only considers one limiting factor, the steam generator outlet pressure, and does not consider the limiting values ​​such as the secondary circuit main feed water flow, the regulating valve opening, and the primary circuit average temperature limit, etc. Moreover, when using method 2 for judgment, the actual thermal power must reach 99% of the rated thermal output to be qualified. However, when the nuclear power unit is operating in winter, it is difficult for the thermal power to reach 99% of the rated thermal output most of the time, so the scope of application is relatively small.

[0008] Therefore, there is an urgent need to design a test judgment method that has wide applicability, comprehensive considerations, simple judgment methods, and can ensure the safe and stable operation of the unit. Summary of the invention

[0009] The purpose of the present invention is to provide a method for determining the rated thermal output test of a nuclear power unit, which can quickly and simply determine whether the rated thermal output of the nuclear power unit meets the design requirements under the premise of ensuring the safe and stable operation of the unit.

[0010] The technical solution of the present invention is as follows:

[0011] A method for determining a rated thermal output test of a nuclear power unit comprises the following steps:

[0012] Step 1: Set the unit status;

[0013] After isolating the corresponding system according to the test requirements, determine the state of the unit during the test;

[0014] Step 2: Thermal balance calculation;

[0015] According to the requirements of the thermal balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , and record relevant parameters by directly reading or searching related files and curves;

[0016] Step 3: Calculate test judgment parameters;

[0017] Calculate the thermal power percentage k 热 , Main water flow percentage k 给水 , actual steam volume flow percentage k 蒸汽 , steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 ;

[0018] Step 4: Rated heat output test determination.

[0019] In step 1, if the condenser back pressure P 试 ≤ Design back pressure P for continuous maximum output condition TMCR , then the unit target power W 电 Increase to near the continuous maximum output design power W 额电 , that is, W 额电 ≥W 电 ≥99.5%W 额电 .

[0020] In step 1, if the condenser back pressure P 试 >Design back pressure P for continuous maximum output condition TMCR , then observe the value N of the thermal power measuring instrument in the main control room 热大 , by gradually increasing the set target power W 电 The method improves the secondary circuit work mass flow rate, and makes N 热大 Close to N额定 .

[0021] In step 2, according to the requirements of the heat balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , the formula is as follows:

[0022] N 计算 =N SG1 +N SG2 +……N SGn

[0023] Where: N 计算 is the thermal power of the nuclear steam supply system, and its value is the same as the thermal power of the primary circuit;

[0024] N SG1 、N SG2…… N SGn is the thermal power of different steam generators. The number n of steam generators in units of different models is different;

[0025] At the same time, record the total flow rate Q of the secondary circuit main water supply at this time 给水 , the average value of the outlet pressure of each steam generator P sg , Average temperature of primary circuit T avg and the primary circuit target temperature T ref , the average temperature limit of a circuit in the operating specification T 规范 , opening of high-pressure cylinder steam inlet regulating valve n, rated value of steam generator outlet pressure P 额sg ; Find the design documents and confirm the design rated main water flow Q 额定 ; Find the valve opening curve and confirm the corresponding steam command flow percentage k when the valve is idle 空程 , the corresponding steam command flow percentage k when the regulating valve opening reaches the limit 限指令 .

[0026] In step 2, the thermal power of each steam generator is calculated as follows:

[0027] N SG =H v Q v -H e Q e

[0028] in:

[0029] H v is the specific enthalpy of wet steam, which is confirmed by the online steam pressure gauge combined with the steam dryness x;

[0030] Q v is the wet steam mass flow rate. The steam generator blowdown system was isolated before the test, so Q v =Q e;

[0031] H e The main feed water specific enthalpy is calculated by the feed water temperature T 给水 and pressure P 给水 Obtained by looking up the table;

[0032] Q e It is the main feed water mass flow rate, measured by online instrument.

[0033] In step 2, H v =xH vs +(1-x)H es , H vs is the saturated steam enthalpy at the steam generator outlet pressure, H es is the saturated water enthalpy value at the steam generator outlet pressure, and x is the dryness of the wet steam at the steam generator outlet.

[0034] In step 3, calculate the thermal power percentage k 热 =N 计算 / N 额定 ;

[0035] Calculate the main water flow percentage k 给水 =Q 给水 / Q 额定 ;

[0036] On the valve control curve, find the corresponding steam command flow percentage k during the test according to the opening n of the high-pressure cylinder steam inlet control valve during the test 指令 , calculate the actual steam volume flow percentage k 蒸汽 =k 指令 -k 空程 ;

[0037] Calculate the steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 =k 限指令 -k 空程 .

[0038] In step 4, if the parameters meet the following requirements at the same time:

[0039] ①k 热 ≥k 给水 ;

[0040] ②k 热 ≥(k 蒸汽 / k 限蒸汽 );

[0041] ③P sg ≥(1-0.5%)P 额sg ;

[0042] ④T avg With T refBoth are less than the average temperature limit T of the first circuit in the operation specification 规范 ;

[0043] It is judged that the rated heat output test of the unit meets the design requirements, that is, the test is qualified;

[0044] Otherwise the test is deemed unqualified.

[0045] The specific steps include:

[0046] Step 1: Set the unit status

[0047] After isolating the corresponding system according to the test requirements, determine the state of the unit during the test;

[0048] If the condenser back pressure P during the test 试 ≤ Design back pressure P for continuous maximum output condition TMCR , then the unit target power W 电 Increase to near the continuous maximum output design power W 额电 , that is, W 额电 ≥W 电 ≥ 99.5%W 额电 ;

[0049] If the condenser back pressure P during the test 试 >Design back pressure P for continuous maximum output condition TMCR , then observe the value N of the thermal power measuring instrument in the main control room 热大 , by gradually increasing the set target power W 电 The method improves the secondary circuit work mass flow rate, and makes N 热大 Close to N 额定 ;

[0050] Step 2: Heat balance calculation

[0051] According to the requirements of the thermal balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , the formula is as follows:

[0052] N 计算 =N SG1 +N SG2 +……N SGn

[0053] Where: N 计算 is the thermal power of the nuclear steam supply system, and its value is the same as the thermal power of the primary circuit;

[0054] N SG1 、N SG2…… N SGnis the thermal power of different steam generators. The number n of steam generators in units of different models is different;

[0055] At the same time, record the total flow rate Q of the secondary circuit main water supply at this time 给水 , the average value of the outlet pressure of each steam generator P sg , Average temperature of primary circuit T avg and the primary circuit target temperature T ref , the average temperature limit of a circuit in the operating specification T 规范 , opening of high-pressure cylinder steam inlet regulating valve n, rated value of steam generator outlet pressure P 额sg ; Find the design documents and confirm the design rated main water flow Q 额定 ; Find the valve opening curve and confirm the corresponding steam command flow percentage k when the valve is idle 空程 , the corresponding steam command flow percentage k when the regulating valve opening reaches the limit 限指令 ;

[0056] Step 3: Calculate test parameters

[0057] Calculate the thermal power percentage k 热 =N 计算 / N 额定 ;

[0058] Calculate the main water flow percentage k 给水 =Q 给水 / Q 额定 ;

[0059] On the valve control curve, find the corresponding steam command flow percentage k during the test according to the opening n of the high-pressure cylinder steam inlet control valve during the test 指令 , calculate the actual steam volume flow percentage k 蒸汽 =k 指令 -k 空程 ;

[0060] Calculate the steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 =k 限指令 -k 空程 ;

[0061] Step 4: Rated heat output test determination

[0062] If the parameters meet the following requirements at the same time:

[0063] ①k 热 ≥k 给水 ;

[0064] ②k 热 ≥(k 蒸汽 / k 限蒸汽 );

[0065] ③P sg ≥(1-0.5%)P 额sg ;

[0066] ④T avg With T ref Both are less than the average temperature limit T of the first circuit in the operation specification 规范 ;

[0067] It is judged that the rated heat output test of the unit meets the design requirements, that is, the test is qualified;

[0068] Otherwise the test is deemed unqualified.

[0069] In step 2, the thermal power of each steam generator is calculated as follows:

[0070] N SG =H v Q v -H e Q e

[0071] in:

[0072] H v is the specific enthalpy of wet steam, which is confirmed by the online steam pressure gauge combined with the steam dryness x, that is: H v =xH vs +(1-x)H es , H vs is the saturated steam enthalpy at the steam generator outlet pressure, H es is the saturated water enthalpy value at the steam generator outlet pressure, and x is the dryness of the wet steam at the steam generator outlet;

[0073] Q v is the wet steam mass flow rate. The steam generator blowdown system was isolated before the test, so Q v =Q e ;

[0074] H e The main feed water specific enthalpy is calculated by the feed water temperature T 给水 and pressure P 给水 Obtained by looking up the table;

[0075] Q e It is the main feed water mass flow rate, measured by online instrument.

[0076] The remarkable effects of the present invention are:

[0077] (1) The method of the present invention meets the requirements of unit design and testing in principle.

[0078] (2) The method of the present invention has a wide application range and can also be used to determine the state where the heat balance calculation value of the unit in the initial state is less than 99% of the design rated heat output value.

[0079] (3) The method of the present invention takes into account the impact of many safety parameters and factors on the unit, and also considers whether the secondary circuit has the ability to perform work to remove the heat of the primary circuit, so the judgment method is more accurate. DETAILED DESCRIPTION

[0080] The present invention is further described in detail below with reference to specific embodiments.

[0081] A method for determining a rated thermal output test of a nuclear power unit comprises the following steps:

[0082] Step 1: Set the unit status

[0083] After isolating the corresponding system according to the test requirements, determine the state of the unit during the test;

[0084] If the condenser back pressure P during the test 试 ≤ Design back pressure P for continuous maximum output condition TMCR , then the unit target power W 电 Increase to near the continuous maximum output design power W 额电 , that is, W 额电 ≥W 电 ≥ 99.5%W 额电 ;

[0085] If the condenser back pressure P during the test 试 >Design back pressure P for continuous maximum output condition TMCR , then observe the value N of the thermal power measuring instrument in the main control room 热大 , under the premise of ensuring sufficient margin for safe and stable operation of the unit, adjust the unit target power W 电 , so that N 热大 As close as possible to the unit's design rated heat output value N 额定 ; That is, by gradually increasing the set target power W 电 The method improves the secondary circuit work mass flow rate, and makes N 热大 Close to N 额定 ;

[0086] Step 2: Heat balance calculation

[0087] According to the requirements of the thermal balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , the formula is as follows:

[0088] N 计算 =NSG1 +N SG2 +……N SGn

[0089] Where: N 计算 is the thermal power of the nuclear steam supply system, and its value is the same as the thermal power of the primary circuit;

[0090] N SG1 、N SG2…… N SGn is the thermal power of different steam generators. The number n of steam generators in units of different models is different.

[0091] The thermal power of each steam generator is calculated as follows:

[0092] N SG =H v Q v -H e Q e

[0093] in:

[0094] H v is the specific enthalpy of wet steam, which is confirmed by the online steam pressure gauge combined with the steam dryness x, that is: H v =xH vs +(1-x)H es , H vs is the saturated steam enthalpy at the steam generator outlet pressure, H es is the saturated water enthalpy value at the steam generator outlet pressure, and x is the dryness of the wet steam at the steam generator outlet;

[0095] Q v is the wet steam mass flow rate. The steam generator blowdown system was isolated before the test, so Q v =Q e ;

[0096] H e The main feed water specific enthalpy is calculated by the feed water temperature T 给水 and pressure P 给水 Obtained by looking up the table;

[0097] Q e It is the main feed water mass flow rate, measured by online instrument.

[0098] At the same time, record the total flow rate Q of the secondary circuit main water supply at this time 给水 , the average value of the outlet pressure of each steam generator P sg , Average temperature of primary circuit T avg and the primary circuit target temperature T ref , the average temperature limit of a circuit in the operating specification T 规范, opening of high-pressure cylinder steam inlet regulating valve n, rated value of steam generator outlet pressure P 额sg ; Find the design documents and confirm the design rated main water flow Q 额定 ; Find the valve opening curve and confirm the corresponding steam command flow percentage k when the valve is idle 空程 , the corresponding steam command flow percentage k when the regulating valve opening reaches the limit 限指令 ;

[0099] Step 3: Calculate test parameters

[0100] Calculate the thermal power percentage k 热 =N 计算 / N 额定 ;

[0101] Calculate the main water flow percentage k 给水 =Q 给水 / Q 额定 ;

[0102] On the valve control curve, find the corresponding steam command flow percentage k during the test according to the opening n of the high-pressure cylinder steam inlet control valve during the test 指令 , calculate the actual steam volume flow percentage k 蒸汽 =k 指令 -k 空程 ;

[0103] Calculate the steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 =k 限指令 -k 空程 ;

[0104] Step 4: Rated heat output test determination

[0105] If the parameters meet the following requirements at the same time:

[0106] ①k 热 ≥k 给水 ;

[0107] ②k 热 ≥(k 蒸汽 / k 限蒸汽 );

[0108] ③P sg ≥(1-0.5%)P 额sg ;

[0109] ④T avg With T ref Both are less than the average temperature limit T of the first circuit in the operation specification 规范 ;

[0110] It is judged that the rated heat output test of the unit meets the design requirements, that is, the test is qualified;

[0111] Otherwise the test is deemed unqualified.

[0112] Example

[0113] The data collected and the calculation results of the rated heat output test of a domestic power plant are as follows:

[0114] Project Name symbol unit Numeric Average value of steam generator outlet pressure <![CDATA[P sg ]]> MPa 6.73 Steam generator outlet humidity x ％ 0.095 Steam generator outlet specific enthalpy <![CDATA[H v ]]> KJ / kg 2775.381 Steam generator 1 water inlet pressure <![CDATA[P 给水1 ]]> MPa 7.05 Steam generator 1 inlet water temperature <![CDATA[T 给水1 ]]> ℃ 255.568 Steam generator 1 water inlet flow <![CDATA[Q e1 ]]> kg / s 530.448 Steam generator 2 water inlet pressure <![CDATA[P 给水2 ]]> MPa 7.088 Steam generator 2 inlet water temperature <![CDATA[T 给水2 ]]> ℃ 225.603 Steam generator 2 water inlet flow <![CDATA[Q e2 ]]> kg / s 536.368 Steam generator 3 water inlet pressure <![CDATA[P 给水3 ]]> MPa 7.062 Steam generator 3 inlet water temperature <![CDATA[T 给水3 ]]> ℃ 225.154 Steam generator 3 water inlet flow <![CDATA[Q e3 ]]> kg / s 531.117 Steam flow rate at steam generator 1 outlet <![CDATA[Q v1 ]]> kg / s 530.448 Steam generator 2 outlet steam flow <![CDATA[Q v2 ]]> kg / s 536.368 Steam generator 3 outlet steam flow <![CDATA[Q v3 ]]> kg / s 531.117 Total flow of main water supply in secondary circuit <![CDATA[Q e ]]> kg / s 1593.933 Calculate reactor thermal power <![CDATA[N 计算 ]]> MWt 2884.914 Percentage nuclear power measured by the nuclear instrumentation system <![CDATA[k 核仪表 ]]> ％ 99.11 Reactor nuclear power rated power <![CDATA[N 额定 ]]> MWt 2905 Rated main water flow <![CDATA[Q 额定 ]]> MWt 1614 Steam generator outlet pressure rating <![CDATA[P 额sg ]]> MPa 6.71 <![CDATA[Find the corresponding percentage k of the steam command flow rate during the test for the valve opening degree n 指令 > <![CDATA[k 指令 ]]> ％ 104.4 The percentage of steam command flow corresponding to the idle stroke of the regulating valve <![CDATA[k 空程 ]]> ％ 4 The percentage of steam command flow corresponding to the valve opening reaching the limit <![CDATA[k 限指令 ]]> ％ 105 Average temperature of primary circuit <![CDATA[T avg ]]> ℃ 309.8 Primary circuit target temperature <![CDATA[T ref ]]> ℃ 309.8 Primary circuit average temperature limit <![CDATA[T 规范 ]]> ℃ 310

[0115] From the above table, we can see that if the traditional test determination method mentioned in the background technology is adopted, the following situations will occur:

[0116] Traditional method 1: Calculate the reactor thermal power N based on the percentage nuclear power measured by the nuclear instrumentation system 计算 After correction, the corrected thermal power is 2910.8MWt, which is greater than the rated thermal power of 2905MWt. The test should be considered qualified.

[0117] Traditional method 2: Calculate reactor thermal power N 计算 Within the range of ±1% of the rated thermal power of 2905MWt, the steam generator outlet pressure P sg Greater than 99.5% rated pressure P 额sg , the test should also be judged as qualified.

[0118] However, during the actual operation of the unit, the actual unit heat output cannot be achieved, and as the unit continues to operate, its primary circuit heat output capacity gradually decreases. Up to now (four cycles have been run), its maximum heat output can only reach about 2850MWt, which is only about 98.1% of the rated value. This shows that there are errors in the traditional test judgment method during the commissioning period, and the actual unit rated heat output does not meet the requirements.

[0119] By using a determination method for a nuclear power unit rated heat output test of the present invention, the parameters calculated are as follows:

[0120] k 热 =99.308%; k 给水 =98.757%; satisfies ①.

[0121] k 蒸汽 =100.4%; k 限蒸汽 =101%; so k 蒸汽 / k 限蒸汽 =99.406%; does not meet ②.

[0122] P sg =6.73MPa; (1-0.5%)P 额sg =6.68MPa; meets ③.

[0123] Tavg =T ref =309.8℃; T 规范 =310℃; meet ④

[0124] The acceptance criteria are as follows:

[0125] ①k 热 ≥k 给水 ;

[0126] ②k 热 ≥(k 蒸汽 / k 限蒸汽 );

[0127] ③P sg ≥(1-0.5%)P 额sg ;

[0128] ④T avg With T ref Both are less than the average temperature limit T of the first circuit in the operation specification 规范 ;

[0129] In summary, although the unit meets the requirements of criteria ①, ③, and ④, it does not meet the requirement of ②, so the test should be judged as unqualified. Calculation and judgment according to this method can better show the actual performance of the unit and conform to the actual status of the subsequent operation of the unit.

[0130] The above shows and describes the basic principles, main features and advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A method for determining a rated thermal output test of a nuclear power unit, characterized in that: The following steps are involved: Step 1: Set the unit status; After isolating the corresponding system according to the test requirements, determine the state of the unit during the test; Step 2: Thermal balance calculation; According to the requirements of the thermal balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , and record relevant parameters by directly reading or searching related files and curves; Step 3: Calculate test judgment parameters; Calculate the thermal power percentage k 热 , Main water flow percentage k 给水 , actual steam volume flow percentage k 蒸汽 , steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 ; Step 4: Rated heat output test determination; In step 1, if the condenser back pressure P 试 ≤ Design back pressure P for continuous maximum output condition TMCR , then the unit target power W 电 Increase to near the continuous maximum output design power W 额电 , that is, W 额电 ≥W 电 ≥99.5%W 额电 ; In step 1, if the condenser back pressure P 试 >Design back pressure P for continuous maximum output condition TMCR , then observe the value N of the thermal power measuring instrument in the main control room 热大 , by gradually increasing the set target power W 电 The method improves the secondary circuit work mass flow rate, and makes N 热大 Close to N 额定 ; In step 2, according to the requirements of the heat balance calculation of the nuclear steam supply system, the primary circuit thermal power N of the unit at this time is calculated by the secondary circuit parameters. 计算 , the formula is as follows: N 计算 =N SG1 +N SG2 +……N SGn Where: N 计算 is the thermal power of the nuclear steam supply system, and its value is the same as the thermal power of the primary circuit; N SG1 、N SG2…… N SGn is the thermal power of different steam generators. The number n of steam generators in units of different models is different; At the same time, record the total flow rate Q of the secondary circuit main water supply at this time 给水 , the average value of the outlet pressure of each steam generator P sg , Average temperature of primary circuit T avg and the primary circuit target temperature T ref , the average temperature limit of a circuit in the operating specification T 规范 , opening of high-pressure cylinder steam inlet regulating valve n, rated value of steam generator outlet pressure P 额sg ; Find the design documents and confirm the design rated main water flow Q 额定 ; Find the valve opening curve and confirm the corresponding steam command flow percentage k when the valve is idle 空程 , the corresponding steam command flow percentage k when the regulating valve opening reaches the limit 限指令 .

2. A method for determining a rated thermal output test of a nuclear power unit according to claim 1, characterized in that: In step 2, the thermal power of each steam generator is calculated as follows: N SG =H v Q v -H e Q e in: H v is the specific enthalpy of wet steam, which is confirmed by the online steam pressure gauge combined with the steam dryness x; Q v is the wet steam mass flow rate. The steam generator blowdown system was isolated before the test, so Q v =Q e ; H e The main feed water specific enthalpy is calculated by the feed water temperature T 给水 and pressure P 给水 Obtained by looking up the table; Q e It is the main feed water mass flow rate, measured by online instrument.

3. A method for determining a rated thermal output test of a nuclear power unit as claimed in claim 2, characterized in that: In step 2, H v =xH vs +(1-x)H es , H vs is the saturated steam enthalpy at the steam generator outlet pressure, H es is the saturated water enthalpy value at the steam generator outlet pressure, and x is the dryness of the wet steam at the steam generator outlet.

4. A method for determining a rated thermal output test of a nuclear power unit as claimed in claim 3, characterized in that: In step 3, calculate the thermal power percentage k 热 =N 计算 / N 额定 ; Calculate the main water flow percentage k 给水 =Q 给水 / Q 额定 ; On the valve control curve, find the corresponding steam command flow percentage k during the test according to the opening n of the high-pressure cylinder steam inlet control valve during the test 指令 , calculate the actual steam volume flow percentage k 蒸汽 =k 指令 -k 空程 ; Calculate the steam volume flow percentage k when the regulating valve opening reaches the limit 限蒸汽 =k 限指令 -k 空程 .

5. A method for determining a rated thermal output test of a nuclear power unit according to claim 4, characterized in that: In step 4, if the parameters meet the following requirements at the same time: ①k 热 ≥k 给水 ; ②k 热 ≥(k 蒸汽 / k 限蒸汽 ); ③P sg ≥(1-0.5%)P 额sg ; ④T avg With T ref Both are less than the average temperature limit T of the first circuit in the operation specification 规范 ; It is judged that the rated heat output test of the unit meets the design requirements, that is, the test is qualified; Otherwise the test is deemed unqualified.

6. A method for determining a rated thermal output test of a nuclear power unit as claimed in claim 5, characterized in that: In step 2, the thermal power of each steam generator is calculated as follows: N SG =H v Q v -H e Q e in: H v is the specific enthalpy of wet steam, which is confirmed by the online steam pressure gauge combined with the steam dryness x, that is: H v =xH vs +(1-x)H es , H vs is the saturated steam enthalpy at the steam generator outlet pressure, H es is the saturated water enthalpy value at the steam generator outlet pressure, and x is the dryness of the wet steam at the steam generator outlet; Q v is the wet steam mass flow rate. The steam generator blowdown system was isolated before the test, so Q v =Q e ; H e The main feed water specific enthalpy is calculated by the feed water temperature T 给水 and pressure P 给水 Obtained by looking up the table; Q e It is the main feed water mass flow rate, measured by online instrument.