CN103808433A - Nuclear power station thermal power measurement drift monitoring method - Google Patents

Abstract

The invention discloses a nuclear power station thermal power measurement drift monitoring method which includes the following steps: monitoring a turbine first-class front pressure variation dQ steam engine and comparing the turbine first-class front pressure variation dQ steam engine to an initial value Q steam engine in fuel circulation; monitoring differential pressure variation dQ water feeding of water feeding flow and comparing the differential pressure variation dQ water feeding to the feeding quality Q water feeding; monitoring the change condition of a function E according to a function (that img file='DDA00002404494200011. TIF' wi= '423' he='134'/); determining that measurement drift happens when the function E exceeds a preset value. By means of the method, the nuclear power station thermal power measurement drift can be monitored online in real time, the drift condition is displayed visually, prevention measures can be taken according to the drift condition, adverse effects caused by the measurement drift are avoided, and safety operation of a nuclear power station is ensured.

Description

Nuclear power station thermal power is measured the monitoring method of drift

[technical field]

The present invention relates to detection technique, particularly a kind of nuclear power station thermal power that is applicable to is measured the detection technique of drifting about.

[background technology]

In the nuclear power station of the U.S., France and various countries' operation such as Chinese, along with the prolongation of working time, frequently there will be nuclear island thermal power to occur the phenomenon of over-evaluating or underestimating, the appearance of this event, has reduced the safety allowance of nuclear power station operation.If do not paid attention to and solve, along with the continuous drift that thermal power is measured, measurement result can present continuous concussion and expand, and even has the control system of causing collapse, causes immeasurable security incident.

The main feedwater flow control of nuclear power generating sets, is to affect the important parameter that steam generator water level regulates, and directly has influence on the safe and stable operation of nuclear power station.

Please refer to the ducted AND DEWATERING FOR ORIFICE STRUCTURE schematic diagram of the main feedwater flow control system of the nuclear power generating sets shown in Fig. 1, in Daya Gulf and the main feedwater flow control system of ridge Australia nuclear power generating sets pipeline, the orifice plate internal diameter theoretical value of installing is 270mm, only need carry out visual inspection according to international standard, require also fairly simple.International standard ISO5167-2003 to the relevant regulations at angle of the face edge is: upstream edge should be right angle, and between orifice plate perforate and upstream face, angle is 90 ° ± 0.3 °, and angle of the face G should be without wiredrawn edge, without burr, also visible any abnormal without range estimation, it is sharp-pointed that angle of the face G should be, as edge radius r _kbeing not more than 0.0004d(d is diameter of bore), can think sharp-pointed.

Orifice plate angle of the face G(is the sharpness of orifice plate ingress edge) after installation and operation, will start to be destroyed.In use, due to the abrasive action of fluid, particularly fluid and the high-temperature steam etc. containing particle for high pressure or high flow rate, its ingress edge rust quickly, is ground into round entrance edge.Consequently: under identical flow, behind aperture, the shrinkage degree of fluid weakens, and differential pressure constantly reduces, can form the negative flow error day by day increasing.The a fluid stream minimum sectional area in orifice plate exit increases after entrance is abraded, if can demarcate under this situation, can find that the efflux coefficient of this orifice plate increases, but still continue to use the less coefficient calculating by normalized form in using, there will be the negative systematic error day by day increasing.So the calculating to the measurement at angle of the face edge to follow-up flow and checking thereof are necessary.

[summary of the invention]

Fundamental purpose of the present invention is: provide a kind of and can Real-Time Monitoring nuclear power station thermal power measure the method for drift.

For this reason, the present invention proposes a kind of nuclear power station thermal power and measure the monitoring method of drift, comprise following process:

To pressure variety dQ before steam turbine one-level _{steam turbine}monitor, and with fuel recycle in initial value Q _{steam turbine}contrast;

To the differential pressure variable quantity dQ of feedwater flow _feedwatermonitor, and with confluent Q _feedwatercontrast; According to function

the situation of change of monitoring function E;

In the time that described function E exceeds predetermined value, judge that thermal power occurs measures drift.

Above-mentioned monitoring method, in embodiment wherein, the situation of change of described function E, obtains for monitoring in whole fuel recycle under all full power mark post operating modes.

Above-mentioned monitoring method, in embodiment wherein, described predetermined value is ± 0.6.

Above-mentioned monitoring method, in embodiment wherein, in the time that the value of described function E exceeds described predetermined value continuously, judges that thermal power occurs measures drift.

Above-mentioned monitoring method, in embodiment wherein, occurs to measure after drift when determining, also comprises the head on process of edge of acute angle radius of the main feedwater flow control system of nuclear power generating sets ducted orifice plate that detects.

Above-mentioned monitoring method, in embodiment wherein, the head on process of edge of acute angle radius of described detection orifice plate adopts three-dimensional scanning survey method, through matching and calculate.

Above-mentioned monitoring method, in embodiment wherein, the head on process of edge of acute angle radius of described detection orifice plate specifically comprises:

Three-dimensional scanning survey: hole circle in orifice plate is divided into some equal portions, determines uniform some measurement points; The each head-on edge of acute angle measurement point of orifice plate is carried out to profile scanning; Gather measurement point spatial value; Obtain the pattern curve of angle of the face;

Matching: the pattern curve of described angle of the face is carried out to matching, obtain head-on edge of acute angle section circle;

Calculate: calculate head-on edge of acute angle radius value take the radius of described circle as measurement point.

Above-mentioned monitoring method, in embodiment wherein, in described computation process, gets the mean value of multiple head-on edge of acute angle radius measurement values as net result.

Above-mentioned monitoring method, in embodiment wherein, described matching adopts least square method or fitting function method or trend collimation method.

Above-mentioned monitoring method, in embodiment wherein, in described three-dimensional scanning survey process, is divided into 8 equal portions by orifice plate inner circle, on circle, determines a measurement point every 45 °.

Above-mentioned monitoring method, in embodiment wherein, in described three-dimensional scanning survey process, the sweep spacing of carrying out profile scanning is set as 5 microseconds.

Above-mentioned monitoring method, in embodiment wherein, one of below described head-on edge of acute angle radius measurement value meets or two conditions time, judge that described orifice plate is defective;

The mean value of multiple described measured values is greater than 0.00032d (d is orifice plate inner diameter values);

In described head-on edge of acute angle radius measurement value, there are three or three to be greater than above 0.0004d (d is orifice plate inner diameter values).

Above-mentioned monitoring method, in embodiment wherein, the detailed process of described matching comprises: edge scanning curve is processed, delete near the useless point of acute angle, choose the extended line that monolateral maximum flex point place, edge does this limit, carry out matching according to scanning circular arc, obtain head-on edge of acute angle section circle; Section circle comprises scanning arc section, and tangent with the extended line of maximum flex point.

By method of the present invention, can realize real-time, on-line monitoring nuclear power station thermal power measurement drift, intuitively present the generation of drift situation, can take preventive measures accordingly, avoid causing thus adverse consequences, guarantee the safe operation of nuclear power station.

And according to measuring drift situation, can be further in time the ducted orifice plate of the main feedwater flow control system of the nuclear power generating sets edge of acute angle radius that heads on be measured, sharpness to orifice plate ingress edge quantizes, can understand better orifice plate at the operating state of nuclear power generating sets, change in time orifice plate, thereby guarantee accurate calculating and the unit safety of nuclear island thermal power.

[accompanying drawing explanation]

Fig. 1 is the ducted AND DEWATERING FOR ORIFICE STRUCTURE schematic diagram of the main feedwater flow control system of nuclear power generating sets;

Fig. 2 is considered as the curve map without the dimensionless function E of drift situation;

Fig. 3 is considered as the curve map of the dimensionless function E that has drift situation;

Fig. 4 three-dimensional scanning survey method schematic diagram;

Fig. 5 is datagraphic and the fitting circle schematic diagram of record;

The imperfect circular fitting circle schematic diagram of Fig. 6 upstream face serious wear;

The imperfect circular fitting circle schematic diagram of Fig. 7 aperture inside diameter surface serious wear;

[embodiment]

Below by specific embodiment, also the present invention is described in further detail by reference to the accompanying drawings.

Embodiment mono-:

Nuclear power plant reactor is in the time of Power operation, and its core power is all take heat Balance Calculation value as benchmark, and its principle is for to obtain reactor core power by Second Ring Road principle of energy balance.In rated power operation situation, if its error analysis is carried out to Correct Analysis, just can guarantee that heat output of reactor can completely send out again in safe operation, meanwhile, also can find the fluctuation of parameter, whether diagnosis in time there is parameter measurement drift.

Determining of heat output of reactor and determining of error

Heat output of reactor computing formula is:

$\mathrm{WR}=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}[(\mathrm{Hvi}-\mathrm{Hei})\mathrm{Qei}-(\mathrm{Hvi}-\mathrm{Hpi})\mathrm{Qpi}]-\mathrm{W\ΔPr}$

Wherein:

We is the feedwater flow of steam generator secondary circuit

Up is the blowdown flow of steam generator secondary circuit

He is the feedwater enthalpy of steam generator secondary circuit

Hp is the sewer enthalpy of steam generator secondary circuit

Hv is the enthalpy of wet steam (kJ/kg) of steam generator secondary circuit outlet

Hv=x Hvs+(1-x)Hes

X is steam generator outlet steam quality (dimensionless)

1-x is the content (dimensionless) of steam generator outlet water from steam

Hes is the enthalpy (kJ/kg) of saturation water

Hvs is saturated vapour enthalpy (kJ/kg)

Footmark SG represents steam generator

Footmark ARE represents feedwater

the relative error of heat output of reactor is as follows:

$\frac{\mathrm{\ΔW}}{W}={\left[\begin{array}{c}{\left[\frac{\mathrm{WSG}1}{W}\frac{\mathrm{\ΔWSG}1}{\mathrm{WSG}1}\right]}^2+{\left[\frac{\mathrm{WSG}2}{W}\frac{\mathrm{\ΔWSG}2}{\mathrm{WSG}2}\right]}^2+\\ {\left[\frac{\mathrm{WSG}3}{W}\frac{\mathrm{\ΔWSG}3}{\mathrm{WSG}3}\right]}^2+{\left[\frac{\mathrm{W\ΔPr}}{W}\frac{\mathrm{\Δ}\left(\mathrm{W\ΔPr}\right)}{\mathrm{W\ΔPr}}\right]}^2\end{array}\right]}^{1/2}$

In above-mentioned expression formula,

value can be considered as constant 0.25, can use down for other three

Row formula calculates:

$\frac{\mathrm{\ΔWSG}}{\mathrm{WSG}}={\left[\begin{array}{c}{\left[\frac{\mathrm{Hv}(\mathrm{Qe}-\mathrm{Qp})}{\mathrm{WSG}}\frac{\mathrm{\ΔHv}}{\mathrm{Hv}}\right]}^2+{\left[\frac{\mathrm{HeQe}}{\mathrm{WSG}}\frac{\mathrm{\ΔHe}}{\mathrm{He}}\right]}^2+{\left[\frac{\mathrm{HpQp}}{\mathrm{WSG}}\frac{\mathrm{\ΔHp}}{\mathrm{Hp}}\right]}^2+\\ {\left[\frac{\mathrm{Qe}(\mathrm{Hv}-\mathrm{He})}{\mathrm{WSG}}\frac{\mathrm{\ΔQe}}{\mathrm{Qe}}\right]}^2+{\left[\frac{\mathrm{Qp}(\mathrm{Hv}-\mathrm{Hp})}{\mathrm{WSG}}\frac{\mathrm{\ΔQp}}{\mathrm{Qp}}\right]}^2\end{array}\right]}^{1/2}$

In the time that blowdown is closed, relational expression can be reduced to:

$\frac{\mathrm{\ΔWSG}}{\mathrm{ESG}}={[{\left[\frac{\mathrm{HvQe}}{\mathrm{WSG}}\frac{\mathrm{\ΔHv}}{\mathrm{Hv}}\right]}^2+{\left[\frac{\mathrm{HeQe}}{\mathrm{WSG}}\frac{\mathrm{\ΔHe}}{\mathrm{He}}\right]}^2+{\left[\frac{\mathrm{Qe}(\mathrm{Hv}-\mathrm{He})}{\mathrm{WSG}}\frac{\mathrm{\ΔQe}}{\mathrm{Qe}}\right]}^2]}^{1/2}$

Thermally equilibrated possible error comprises stochastic error and systematic error:

A) calculating of stochastic error:

The error of measured value is listed below:

◆ feed temperature error delta t _aRE/ t _aRE

$\mathrm{\Δ}{t}_{\mathrm{ARE}}/t_{\mathrm{ARE}}={[{(E\_\mathrm{Pt}100)}^2+{(E\_\mathrm{thermowell})}^2+{(E\_3144)}^2+{(E\_\mathrm{AVE})}^2+{(E\_\mathrm{ACQ})}^2]}^{0.5}$

$={[{(0.067\%)}^2+{(0.22\%)}^2+{(0.056\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2+{(0.02\%)}^2]}^{0.5}$

$={[{(0.24\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2]}^{0.5}$

Wherein:

E_Pt100 is the error based on RTD.

E_thermowell is the error that temperature survey causes after sleeve pipe.

E_3144 is the error based on temperature transmitter.

E_AVE is the uncertainty that sampled point is averaged and the error causing

E_ACQ is the error based on acquisition module, comprises isolated amplifier error and ADC error.

Feed pressure error delta P _aRE/ P _aRE

$\mathrm{\Δ}{P}_{\mathrm{ARE}}/P_{\mathrm{ARE}}={[{(E\_3051)}^2+{(E\_\mathrm{LONGTIME})}^2+{(E\_\mathrm{AVE})}^2+{(E\_\mathrm{ACQ})}^2]}^{0.5}$

$={[{(0.15\%)}^2+{(0.1\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2+{(0.02\%)}^2]}^{0.5}$

$={[{(0.18\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2]}^{0.5}$

Wherein:

E_3051 is the error based on pressure unit

E_LONGTIME is long-time stability error.

E_AVE is the uncertainty that sampled point is averaged and the error causing.

E_ACQ is the error based on acquisition module, comprises isolated amplifier error and ADC error.

ARE bias error Δ (Δ P _aRE)/Δ P _aRE

$\mathrm{\Δ}\left(\mathrm{\Δ}{P}_{\mathrm{ARE}}\right)/{\mathrm{\ΔP}}_{\mathrm{ARE}}={[{(E\_3051)}^2+{(E\_\mathrm{LONGTIME})}^2+{(E\_\mathrm{AVE})}^2+{(E\_\mathrm{ACQ})}^2]}^{0.5}$

$={[{(\frac{2}{3}\×0.15\%\×\frac{\left(\mathrm{\ΔP}\right)\max }{\left(\mathrm{\ΔP}\right)\mathrm{mea}})}^2+{(0.1\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2+{(0.02\%)}^2]}^{0.5}$

$={[{(0.18\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2]}^{0.5}$

Wherein:

E_3051 is the error based on pressure unit

E_LONGTIME is long-time stability error.

E_AVE is the uncertainty that sampled point is averaged and the error causing.

E_ACQ is the error based on acquisition module, comprises isolated amplifier error and ADC error.

VVP pressure error Δ P _vVP/ P _vVP

$\mathrm{\Δ}{P}_{\mathrm{VVP}}/P_{\mathrm{VVP}}={[{(E\_3051)}^2+{(E\_\mathrm{LONGTIME})}^2+{(E\_\mathrm{AVE})}^2+{(E\_\mathrm{ACQ})}^2]}^{0.5}$

$={[{(0.15\%)}^2+{(0.1\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2+{(0.02\%)}^2]}^{0.5}$

$={[{(0.18\%)}^2+{(\frac{2\mathrm{\σ}}{\sqrt{\mathrm{NB}\_\mathrm{ACQ}}}*100\%)}^2]}^{0.5}$

Wherein:

E_3051 is the error based on pressure unit

E_LONGTIME is long-time stability error

E_AVE is the uncertainty that sampled point is averaged and the error causing.

E_ACQ is the error based on acquisition module, comprises isolated amplifier error and ADC error.

The error of calculated value is listed below:

$\frac{\mathrm{\ΔHvi}}{\mathrm{Hvi}}={[{\left[\frac{\mathrm{xi}}{\mathrm{Hvi}}(\mathrm{Hvsi}-\mathrm{Hesi})\frac{\mathrm{\Δxi}}{\mathrm{xi}}\right]}^2+{\left[\frac{\mathrm{Hvsi}}{\mathrm{Hvi}}\mathrm{xi}\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}\right]}^2+{\left[\frac{\mathrm{Hesi}}{\mathrm{Hvi}}(1-\mathrm{xi})\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}\right]}^2]}^{1/2}$

Wherein $\frac{\mathrm{\Δ}(1-\mathrm{xi})}{1-\mathrm{xi}}=\frac{\mathrm{xi}}{1-\mathrm{xi}}\·\frac{\mathrm{\Δxi}}{\mathrm{xi}}=1$

So:

$\frac{\mathrm{\Δxi}}{\mathrm{xi}}=\frac{1-\mathrm{xi}}{\mathrm{xi}}$

The error of saturated vapour enthalpy is from tonometric error, and the ASME formula error of calculating water and steam thermodynamic properties.Therefore:

$\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}={[{\left(\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}\right)}_{\mathrm{Pvi}}^2+{\left(\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}\right)}_f^2]}^{1/2}$

Based on tonometric error be:

${\left(\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}\right)}_{\mathrm{Pvi}}=\frac{\mathrm{Pvi}}{\mathrm{Hvsi}}\left|\frac{\∂\mathrm{Hvsi}}{\∂\mathrm{Pvi}}\right|\frac{\mathrm{\ΔPvi}}{\mathrm{Pvi}}$

by obtaining after the differentiate of ASME formula.

ASME formula error in steam generator range of operation is 4kJ/kg, therefore:

${\left(\frac{\mathrm{\ΔHvsi}}{\mathrm{Hvsi}}\right)}_f=\frac{4}{\mathrm{Hvsi}}$

The error of saturation water enthalpy is from tonometric error, and the ASME formula error of the thermodynamic properties of calculating water and steam.Therefore:

$\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}={[{\left(\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}\right)}_{\mathrm{Pvi}}^2+{\left(\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}\right)}_f^2]}^{1/2}$

Based on tonometric error be:

${\left(\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}\right)}_{\mathrm{Pvi}}=\frac{\mathrm{Pvi}}{\mathrm{Hesi}}\left|\frac{\∂\mathrm{Hesi}}{\∂\mathrm{Pvi}}\right|\frac{\mathrm{\ΔPvi}}{\mathrm{Pvi}}$

after deriving from the differentiate of ASME formula, obtain.

ASME formula error in steam generator range of operation is 0.8kJ/kg, therefore:

${\left(\frac{\mathrm{\ΔHesi}}{\mathrm{Hesi}}\right)}_f=\frac{0.8}{\mathrm{Hesi}}$

Because the coefficient of cubical elasticity of water is very large, so tonometric error is just negligible on the impact of the feedwater enthalpy error of calculation.In the feedwater enthalpy error of calculation, only consider thermometric error and ASME formula error.Therefore:

$\frac{\mathrm{\ΔHei}}{\mathrm{Hei}}={[{\left(\frac{\mathrm{\ΔHei}}{\mathrm{Hei}}\right)}_{\mathrm{tei}}^2+{\left(\frac{\mathrm{\ΔHei}}{\mathrm{Hei}}\right)}_f^2]}^{1/2}$

Based on the probabilistic error of temperature survey be:

${\left(\frac{\mathrm{\ΔHei}}{\mathrm{Hei}}\right)}_{\mathrm{tei}}=\frac{\mathrm{tei}}{\mathrm{Hei}}\left|\frac{\∂\mathrm{Hei}}{\∂\mathrm{tei}}\right|\frac{\mathrm{\Δtei}}{\mathrm{tei}}$

after ASME formula differentiate by calculating feedwater enthalpy, obtain.

ASME formula error in steam generator range of operation is 0.5kJ/kg, therefore:

${\left(\frac{\mathrm{\ΔHei}}{\mathrm{Hei}}\right)}_f=\frac{0.5}{\mathrm{Hei}}$

According to ISO5167 (2003), the standard deviation of feedwater enthalpy is:

$\frac{\mathrm{\σQei}}{\mathrm{Qei}}={\left[\begin{array}{c}{\left(\frac{\mathrm{\σCi}}{\mathrm{Ci}}\right)}^2+{\left(\frac{\mathrm{\σ\ϵi}}{\mathrm{\ϵi}}\right)}^2+4{\left(\frac{{\mathrm{\βi}}^4}{1-{\mathrm{\βi}}^4}\right)}^2{\left(\frac{\mathrm{\σDi}}{\mathrm{Di}}\right)}^2+4{\left(\frac{1}{1-{\mathrm{\βi}}^4}\right)}^2{\left(\frac{\mathrm{\σdi}}{\mathrm{di}}\right)}^2\\ +\frac{1}{4}{\left(\frac{\mathrm{\σ\ΔPi}}{\mathrm{\ΔPi}}\right)}^2+\frac{1}{4}{\left(\frac{\mathrm{\σ\ρi}}{\mathrm{\ρi}}\right)}^2\end{array}\right]}^{1/2}$

$\frac{\mathrm{\ΔQei}}{\mathrm{Qei}}=2\frac{\mathrm{\σQei}}{\mathrm{Qei}}$

The standard deviation of the coefficient of flow to flange tapping standard orifice plate is:

0.1≤β<0.2 $\frac{\mathrm{\&sigma;Ci}}{\mathrm{Ci}}=\&PlusMinus;(0.7-\mathrm{\&beta;})\%$

0.2≤β≤0.6 $\frac{\mathrm{\&sigma;Ci}}{\mathrm{Ci}}=\&PlusMinus;0.5\mathrm{\&beta;}\%$

0.6<β≤0.75 $\frac{\mathrm{\&sigma;Ci}}{\mathrm{Ci}}=\&PlusMinus;(1.66\mathrm{\&beta;}-0.5)\%$

According to ISO5167 (2003), incompressible fluid equal zero, that is to say:

$\frac{\mathrm{\&sigma;\&epsiv;i}}{\mathrm{\&epsiv;i}}=0$

The error of calculation of pipe diameter is:

$\frac{\mathrm{\&Delta;Di}}{\mathrm{Di}}={({\left(\frac{\mathrm{\&Delta;}{D}_{i0}}{D_{i0}}\right)}^2+{\left(\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{\mathrm{Ti}}^{\&prime;}}{{\mathrm{\&lambda;}}_{\mathrm{Ti}}^{\&prime;}}\right)}^2+{\left(\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{T0i}^{\&prime;}}{{\mathrm{\&lambda;}}_{T0i}^{\&prime;}}\right)}^2)}^{1/2}$

$\frac{\mathrm{\&sigma;Di}}{\mathrm{Di}}=\frac{1}{2}\frac{\mathrm{\&Delta;Di}}{\mathrm{Di}}$

relevant with the instrument of measuring channel cold conditions size.

with calculate use table or scheme relevant.

The error of calculation of orifice plate diameter is:

$\frac{\mathrm{\&Delta;di}}{\mathrm{di}}={[{\left(\frac{\mathrm{\&Delta;}{d}_{i0}}{d_{i0}}\right)}^2+{\left(\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{\mathrm{ti}}}{{\mathrm{\&lambda;}}_{\mathrm{ti}}}\right)}^2+{\left(\frac{\mathrm{\&Delta;}{\mathrm{\&lambda;}}_{t0i}}{{\mathrm{\&lambda;}}_{t0i}}\right)}^2]}^{1/2}$

$\frac{\mathrm{\&sigma;di}}{\mathrm{di}}=\frac{1}{2}\frac{\mathrm{\&Delta;di}}{\mathrm{di}}$

relevant with the instrument of measuring diaphragm cold conditions diameter, if orifice plate diameter is revised value.

with calculate use table or scheme relevant.

Because the coefficient of cubical elasticity of water is very large, so tonometric error is just negligible on the impact of the feedwater enthalpy error of calculation.In the feedwater enthalpy error of calculation, only consider thermometric error and ASME formula error.Therefore:

$\left(\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}\right)={[{\left(\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}\right)}_{\mathrm{tei}}^2+{\left(\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}\right)}_f^2]}^{1/2}$

$\frac{\mathrm{\&sigma;\&rho;i}}{\mathrm{\&rho;i}}=\frac{1}{2}\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}$

Based on the probabilistic error of temperature survey be:

${\left(\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}\right)}_{\mathrm{tei}}=\frac{\mathrm{tei}}{\mathrm{\&rho;i}}\left|\frac{\&PartialD;\mathrm{\&rho;i}}{\&PartialD;\mathrm{tei}}\right|\frac{\mathrm{\&Delta;tei}}{\mathrm{tei}}$

after ASME formula differentiate by calculating feedwater enthalpy, obtain.

ASME formula error in steam generator range of operation is 410 ^-7m ³/ kg, therefore:

${\left(\frac{\mathrm{\&Delta;\&rho;i}}{\mathrm{\&rho;i}}\right)}_f={\left(\frac{\mathrm{\&Delta;vi}}{\mathrm{vi}}\right)}_f=\mathrm{\&rho;i\&Delta;vi}$

According to above formula, can obtain the margin of error of heat output of a reactor and every calculating parameter.

When calculating reactor capability, record electric signal outrange situation, the electric signal after conversion is carried out to super electric range check, the mass property of specified data is as follows:

Good data: in range ability

Suspicious data: exceed electric weight journey but in allowed band

Invalid data: super electric weight journey exceedes allowed band

Super electric weight journey allowed band be set be signal full range 0%, 2%, 5% and 10%4 grades, the data of invalid and suspicious collection are rejected, and regulation rejecting ratio is while being greater than 5%, signal confidence level is reduced to needs investigation, early warning power excursion.

During unit operation, by supervision unit operational factor, judge whether to exist nuclear island power excursion.Concrete grammar is at run duration, variable quantity to pressure before the steam turbine one-level of secondary circuit monitors, and contrast with the initial value in fuel recycle, with the differential pressure variable quantity of feedwater flow and the ratio of the front pressure of one-level, determine whether to occur and power excursion.

Before and after can obtaining variable working condition by Fu Liugeer Flugel formula, throughput ratio is:

$\frac{G_1}{G}=\sqrt{\frac{P_{01}^2-P_{Z1}^2}{P_0^2-P_Z^2}}\&times;\sqrt{\frac{T_0}{T_{01}}}---\left(1\right)$

From Fu Liugeer formula (1) was derived (2) formula, the feature representation formula as through-current capability:

$F=G\&times;\sqrt{T_0}\&times;\sqrt{\frac{1}{P_0^2-P_Z^2}}---\left(2\right)$

Fu Liugeer has done a basic supposition, and flow area remains unchanged, once and circulation area changes, above-mentioned relation formula is false.

As can be seen here, if the flow area of unit remains unchanged, in the situation that ignoring temperature variation, the pressure ratio of adjacent level group remains unchanged in variable working condition.This can be used as to detect whether turbine flow passage component fault is damaged or the foundation of fouling, otherwise can check the accuracy of nuclear island thermal power.If variation has occurred the front and back pressure ratio of certain grade of group, there is change or flow measurement of steam changes in the aisle spare of this grade of group.

General kernel power station unit band basic load; the evaporator of nuclear power station is stricter than conventional thermoelectricity to water quality requirement simultaneously; can there is not fouling and corrosion in the whole service cycle in blade; through-flowly can not change; so can adopt Fu Liugeer formula, by monitoring before and after daily or overhaul that section pressure changes to verify the accuracy of maximum error source feedwater flow (steam flow) in KME.

Accurate for guaranteeing precision, verification condition requires unit band basic load, identical or approaching in the cycle of operation or former and later two operating mode thermal powers (flow) of overhaul.

Nuclear steam turbine service data based on a large amount of, formula (2) is verified in the stability of overhaul front and back or the operating mode of the cycle of operation, fact proved, its stability very high (approximately 0.1%), especially steam turbine high-pressure cylinder first paragraph, according to formula, we found APG blowdown flow problem (0.2%).

For this reason, by the F called after feature flow area of formula (2), set it as the sign of through-flow level section performance, choose normal data and obtain F, before and after run duration or overhaul, compare with it, can verify the accuracy of KME flow.

In fact, approaching under rated heat input, rated heat load condition, high pressure cylinder is saturated vapour, and two working temperature variations are very little, and Fu Liugeer Fl uge l formula can be reduced to:

F _j＝G/P ₀ （4）

Stability to formula (4) is also verified, fact proved, its stability is very high (approximately 0.2%) also.

From analysis above, as long as can accurately measure the value of the each extraction pressure of steam turbine, and the extraction pressure value under each main steam flow when grasping unit and moving first or after certain overhaul, just can obtain more exactly the feature representation formula of this steam turbine through-current capability, the accuracy of nuclear island thermal power is verified.

Be directly proportional to the steam flow that enters steam turbine by the power of discussing above known steam turbine, and before one-level, pressure is the characteristic parameter of reflection steam turbine flow, therefore sets up dimensionless function in whole fuel recycle, supervise the situation of change of all full power mark post operating modes.Concrete supervision situation as shown in the figure, please refer to shown in Fig. 2, in the time that the value of dimensionless function E is drifted about always and is not exceeded warning value ± 0.6 in-0.4 to 0.4 scope, within proving to measure the scope that drifts in rationally, allows, measurement result can directly adopt, and is considered as existing without measuring drift situation; Now, need not further process for this reason, detect or shut down maintenance etc.Please refer to shown in Fig. 3; in the time that the value of dimensionless function E repeatedly exceeds warning value ± 0.6; prove to measure the scope that drift has exceeded rationally, allowed; be considered as existing drift situation; if measurement result now is directly adopted, by the amplification of control system, must cause control system to take self-protection measure; nuclear power station is disorderly closedown therefore, brings huge operation loss and potential safety hazard.Now, must take an immediate action, check related sensor and nuclear island measuring instrument, whether checking really there is nuclear island power measurement value drift.And emphasis checks orifice plate and other relevant devices in overhaul.

Whether most sensor and nuclear island measuring instrument, can occur to measure drift by On line inspection, and take compensation or remedial measures.But the orifice plate in steam turbine flow detection, cannot carry out On line inspection, can only in the time of overhaul, check.

Because orifice plate is the metal material of high temperature resistant, high pressure, corrosion, orifice plate is arranged in machine set system, and the abraded quantity that ingress edge can be subject to fluid is quite little.Known to the data measured of the edge of acute angle radius that heads on by long-time (continuing several years), orifice plate is along with the increase of the on-line operation time limit, and head-on edge of acute angle radius can become greatly year by year, but most data centralization is distributed within the scope of (0.010-0.108) mm.In order to record so small radius value, the present embodiment uses three coordinate measuring machine and measuring machine three-dimensional coordinates measurement software head on measurement and the matching of edge of acute angle radius, and has formulated the judge requirement whether the edge of acute angle radius that heads on meets the demands.

The limits of error of the three coordinate measuring machine using in work are ± (1.5+3L/1000) μ m, and wherein L is for measuring length, and unit is mm.Actual measurement length in the calibration certificate of providing according to the third-party institution and work, the measuring error of three coordinate measuring machine is less than 1 μ m.

It is three-dimensional scanning survey method that measuring method adopts, and main dependence is the scan function of three coordinate measuring machine probe with high precision.Concrete measuring method is, hole circle equalization in orifice plate is divided into 8 parts, on circle, determine a measurement point every 45 °, use the scanning feeler of three coordinate measuring machine to carry out profile scanning to the each head-on edge of acute angle measurement point of flow-through orifice, direction of scanning is " direction one " to " direction two " motion in figure, as shown in Figure 4.And determine suitable sweep spacing, measuring machine is every gathers a coordinate figure through a sweep spacing.Utilize the volume coordinate matching of three coordinate measuring machine measured value to form the pattern curve of angle of the face, calculate head-on edge of acute angle radius r by software _kvalue, ask its 8 r _kthe mean value of value, using this as the edge of acute angle radius r that heads on _knet result.

In measuring machine, set profile scanning program, the sweep spacing of measuring machine is set as to 5 μ m, make scanning feeler along each head-on edge of acute angle section image data successively.Record data in scanning process, and form the head-on scanning pattern of edge of acute angle section.The circular shape obtaining according to scanning, people chooses suitable arc section to carry out least square fitting, finally obtains head-on edge of acute angle section circle, and edge of acute angle radius value r heads on using this radius of circle as measurement point _k, as shown in Figure 5.

Head-on edge of acute angle scanning patter shown in Fig. 5 is the desirable state that approaches after it weares and teares in fluid.But the flow state of fluid is complicated in on-the-spot pipeline, in fluid, may be mingled with impurity simultaneously, this brings very large uncertainty to the head on degree of wear of edge of acute angle of orifice plate.According to measurement experience in the past, the most head-on degree of wear of edge of acute angle has all departed from perfect condition greatly.

Two kinds of typical imperfect circular arcs in head-on edge of acute angle scanning patter shown in Fig. 6 and Fig. 7, the upstream face that the scanning patter of Fig. 6 has shown orifice plate is comparatively serious by fluid abrasion, causes upstream face to lack one; The scanning patter of Fig. 7 has shown the comparatively serious of orifice plate inside diameter surface wearing and tearing, causes aperture surface to lack one.

Head-on the measurement overall process of edge of acute angle is all automatically to be carried out according to the program of setting by three coordinate measuring machine, and people is that the error of bringing into can be ignored, and edge of acute angle radius value r finally heads on _kthe whether accurate method that only relies on artificial fitting circle.In order to form the head on matching way of edge of acute angle section circle of the orifice plate of nuclear power generating sets, for two kinds of nonidealities in Fig. 6 and Fig. 7, this example adopts the head-on matching rule of edge of acute angle section circle: edge scanning curve is processed, delete near the useless point of acute angle, choose the extended line that monolateral maximum flex point place, edge does this limit, carry out matching according to scanning circular arc, fitting circle need comprise scanning arc section as far as possible, and tangent with the extended line of maximum flex point, edge of acute angle radius value heads on using this this radius of a circle value as orifice plate.

By measuring and artificial fitting's circle, obtain 8 r _kvalue, final head-on edge of acute angle radius value r _kfor the mean value of these 8 values.

Complete measurement and matching, will obtain 9 head-on edge of acute angle radius value r _k, pass judgment on the running status of orifice plate according to these data, this example has been formulated nuclear power generating sets to the orifice plate edge of acute angle radius value r that heads on _kjudge rule, specific as follows:

1) orifice plate head on edge of acute angle should be without wiredrawn edge or burr, head-on edge of acute angle radius value r _kshould be not more than 0.0004d ,≤0.108mm, generally can detect by an unaided eye, and check edge not folded light beam also can be by other device measuring edge radius;

2) edge of acute angle radius value r head-on _kunderproof decision principle:

A) in 8 values, having 3 values to be greater than 0.0004d(d is orifice plate inner diameter values);

B) mean value to be greater than 0.00032d(d be orifice plate inner diameter values).

By this example, can realize real-time oversight nuclear power station thermal power and measure drift, intuitively present the generation of drift situation; Once there is drift situation, the various kinds of sensors of detection system accordingly, and machine testing flow-through orifice while utilizing overhaul, change orifice plate in time, avoids causing thus adverse consequences.And according to measuring drift situation, in time the orifice plate of the steam turbine flow control system edge of acute angle radius that heads on is measured, sharpness to orifice plate ingress edge quantizes, can understand better orifice plate at the operating state of nuclear power generating sets, change in time orifice plate, thereby guarantee accurate calculating and the unit safety of nuclear island thermal power.

Above content is in conjunction with concrete preferred implementation further description made for the present invention, can not assert that specific embodiment of the invention is confined to these explanations.For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.Such as, by the instruction of the embodiment of the present invention, those skilled in the art are known, and the matching in embodiment can also adopt the method such as function method, trend collimation method; For setting of the choosing of measurement point, sweep spacing etc., also can make accommodation.

Claims (13)

1. nuclear power station thermal power is measured a monitoring method for drift, comprises following process:

To pressure variety dQ before steam turbine one-level _{steam turbine}monitor, and with fuel recycle in initial value Q _{steam turbine}contrast;

To the differential pressure variable quantity dQ of feedwater flow _feedwatermonitor, and with confluent Q _feedwatercontrast; According to function the situation of change of monitoring function E;

In the time that described function E exceeds predetermined value, judge that thermal power occurs measures drift.

2. monitoring method as claimed in claim 1, is characterized in that: the situation of change of described function E, obtains for monitoring in whole fuel recycle under all full power mark post operating modes.

3. monitoring method as claimed in claim 1, is characterized in that: described predetermined value is ± 0.6.

4. monitoring method as claimed in claim 1, is characterized in that: when the value of described function E exceeds described predetermined value continuously, judge that thermal power occurs measures drift.

5. the monitoring method as described in any one in claim 1-4, is characterized in that: occur to measure after drift when judging, also comprise the head on process of edge of acute angle radius of the main feedwater flow control system of nuclear power generating sets ducted orifice plate that detects.

6. monitoring method as claimed in claim 5, is characterized in that: the head on process of edge of acute angle radius of described detection orifice plate adopts three-dimensional scanning survey method, through matching and calculate.

7. monitoring method as claimed in claim 6, is characterized in that: the head on process of edge of acute angle radius of described detection orifice plate specifically comprises:

Three-dimensional scanning survey: hole circle in orifice plate is divided into some equal portions, determines uniform some measurement points; The each head-on edge of acute angle measurement point of orifice plate is carried out to profile scanning; Gather measurement point spatial value; Obtain the pattern curve of angle of the face;

Matching: the pattern curve of described angle of the face is carried out to matching, obtain head-on edge of acute angle section circle;

Calculate: calculate head-on edge of acute angle radius value take the radius of described circle as measurement point.

8. monitoring method as claimed in claim 7, is characterized in that: in described computation process, get the mean value of multiple head-on edge of acute angle radius measurement values as net result.

9. monitoring method as claimed in claim 7, is characterized in that: described matching adopts least square method or fitting function method or trend collimation method.

10. monitoring method as claimed in claim 7, is characterized in that: in described three-dimensional scanning survey process, orifice plate inner circle is divided into 8 equal portions, on circle, determines a measurement point every 45 °.

11. monitoring methods as claimed in claim 7, is characterized in that: in described three-dimensional scanning survey process, the sweep spacing of carrying out profile scanning is set as 5 microseconds.

12. monitoring methods as claimed in claim 7, is characterized in that: one of below described head-on edge of acute angle radius measurement value meets or two conditions time, judge that described orifice plate is defective;

The mean value of multiple described measured values is greater than 0.00032d (d is orifice plate inner diameter values);

In described head-on edge of acute angle radius measurement value, there are three or three to be greater than above 0.0004d (d is orifice plate inner diameter values).

13. monitoring methods as claimed in claim 9, it is characterized in that: the detailed process of described matching comprises: edge scanning curve is processed, choose the extended line that monolateral maximum flex point place, edge does this limit, carry out matching according to scanning circular arc, obtain head-on edge of acute angle section circle; Section circle comprises scanning arc section, and tangent with the extended line of maximum flex point.

Images