CN1274162A - Method for measuring power of pressurized-water reactor core for nuclear power station - Google Patents

Abstract

A method for measuring the power of pressurized-water reactor core for nuclear power station features that the temp, pressure and flow of the working media in two loops in the steam generator of said pressurized-water reactor care measured, the raised enthalpy value generated when said working media flow through the steam generator is calculated to obtain the energy transferred from the first to the second loops, the energy obtained by the first loop via other equipment and the energy lost by it are considered, and the power of said reactor core is finally calculated out. Its advantages include high speed and accuracy.

Description

A kind of method for measuring power of pressurized-water reactor core for nuclear power station

The invention belongs to the measuring power of pressurized-water reactor core for nuclear power station technology.

Nuclear power station run duration, pressurized-water reactor core power are crucial parameters.Have only core power is measured accurately and rapidly, could guarantee reactor safety, economical operation.If the core power measured value is lower than actual value, reactor will move above under the condition of its operational factor, and reactor burns out easily, thus initiation reaction heap accident, crisis equipment and personal safety.On the contrary, if the core power measured value is higher than actual value, reactor does not reach its specified service condition, and outside liberated heat of reactor and the generated energy that causes thus all are lower than design load, and the economy of unit will be affected.

For pressurized-water reactor core power, useful in the world heat balance principle is measured.The heat balance method of that two the pressurized-water reactor core power in China GNPS adopt Electricite De France to provide is measured.There are two circulating water loops in presurized water reactor, the solar heat protection of one loop works medium absorption reaction heap, and heat is passed to the water of secondary circuit by heat exchanger, the water of secondary circuit becomes the very high wet saturated steam of mass dryness fraction after absorbing heat, promote the gas-turbine work done, finally heat energy is become the electric energy of generator.Heat balance method of is exactly by measuring the heat that the secondary circuit actuating medium obtains, consider the internal heat loss simultaneously, calculating the reactor liberated heat, thereby obtain reactor core power.By actual measurement temperature, pressure and flow, can obtain reactor core power more exactly by heat balance method of, but in the heat Balance Calculation method that Electricite De France provides, what the water and steam thermodynamic properties calculated employing is simple binomial method, plays a computational accuracy and remains further to be improved.

The purpose of this invention is to provide a kind ofly, can improve the measuring method of pressurized-water reactor core power measurement precision utilizing on the basis of heat balance method of.

Technical scheme of the present invention is: a kind of method for measuring power of pressurized-water reactor core for nuclear power station is characterized in that:

(1) will handle PC and be connected with the data acquisition PC, the data acquisition PC is connected with the isolation acquisition module, isolates acquisition module and is connected with the in-site measurement signal wire;

(2) gather correlation parameter by isolating acquisition module, and the parameter that collects is input to acquisition PC machine, utilize the data of acquisition PC machine, the program by in the operation processing PC just can obtain reactor core power, and its concrete steps are:

1) the constant data that need in the time of will measuring are input to be handled in the PC, these data comprise: 1. jet chimney diameter D, steam generator export to the length L of pressure unit interface under the reference temperature, difference in height Δ z between pressure unit and steam pipe axis, coefficient of friction resistance λ, 2. main feed system pipe diameter D under the reference temperature ₁, the length L of inlet from the main feed system to the steam generator ₁, the difference in height Δ z of pressure unit and feed pipe between centers ₁, coefficient of friction resistance λ ₁, the 3. feedwater orifice plate diameter d under the reference temperature _e, give water conduit circular section diameter D under the reference temperature _e, the 4. mudhole board diameter d under the reference temperature _p, reference temperature down blow conduit circular section diameter D _p:

2) calculate momentum parameter by isolating the acquisition module collection, these data comprise: 1. steam generator top hole pressure P _Vvp, steam mean flow rate V, steam generator outlet steam quality x is steam generator inlet pressure P 2. _Are, the pressure differential deltap that 3. feeds water P _e, 4. blowdown pressure differential deltap P _Pl

3) handling PC utilizes momentum parameter and constant parameter to calculate, the feedwater flow, blowdown flow, steam flow, feedwater enthalpy, blowdown enthalpy, outlet enthalpy of wet steam and other thermals source that calculate each secondary circuit of steam generator are passed to the heat of reactor cooling system, and the concrete operation way is:

1. calculate each secondary circuit enthalpy of wet steam: according to formula

Calculate the steam generator top hole pressure, according to this pressure value, calculate the enthalpy of saturation water and saturated dry steam under this pressure by the ASME formula, obtain the enthalpy of wet steam again according to the mass dryness fraction of wet steam, concrete computing formula is as follows:

Be relative pressure,

Be relative temperature, Be relative specific volume,

Be relative enthalpy, wherein P _C, T _C, V _CBe the value of critical point, when the pressure of known saturation water or saturated vapour, can iterate by following formula and try to achieve saturation temperature: $\mathrm{\β}\left(\mathrm{\θ}\right)=\exp (\frac{1}{\mathrm{\θ}}\frac{\underset{i=1}{\overset{5}{\mathrm{\Σ}}}{k}_i{(1-\mathrm{\θ})}^i}{1+k_6(1-\mathrm{\θ})+k_7{(1-\mathrm{\θ})}^2}-\frac{(1-\mathrm{\θ})}{k_8{(1-\mathrm{\θ})}^2+k_9})$ The computing formula of unsaturated water and saturation water is: x ₁=A ₁₁a ₅Z ^-5/17+ { A ₁₂+ A ₁₃θ+A ₁₄θ ²+ A ₁₅(a ₆-θ) ¹⁰+ A ₁₆(a ₇+ θ ¹⁹) ^-1}

-(a ₈+θ ¹¹) ^-1(A ₁₇+2A ₁₈β+3A ₁₉β ²)

-A ₂₀θ ¹⁸(a ₉+θ ²){-3(a ₁₀+β) ^-4+a ₁₁}+3A ₂₁(a ₁₂-θ)β ²

+ 4A ₂₂θ ^-20β ³Wherein:

Z＝Y+(a ₃Y ²-2a ₄θ+2a ₅β) ^1/2

Y＝1-a ₁θ ²-a ₂θ ^-6 ${\mathrm{\ϵ}}_1=a_0+A_0\mathrm{\θ}-\underset{v=1}{\overset{10}{\mathrm{\Σ}}}(v-2)A_v{\mathrm{\θ}}^{v-1}+A_{11}\left[Z\right\{17(\frac{Z}{29}-\frac{Y}{12})+5\mathrm{\θ}\frac{Y^{\′}}{12}\}+a_4\mathrm{\θ}-(a_3-1)\mathrm{\θY}{Y}^{\′}]Z^{-5/17}$

+{A ₁₂-A ₁₄θ ²+A ₁₅(9θ+a ₆)(a ₆-θ) ⁹+A ₁₆(20θ ¹⁹+a ₇)(a ₇+θ ¹⁹) ^-2}β

-(12θ ¹¹+a ₈)(a ₈+θ ¹¹) ^-2(A ₁₇β+A ₁₈β ²+A ₁₉β ³)+A ₂₀θ ¹⁸(17a ₉+19θ ²){(a ₁₀+β) ^-3+a ₁₁β}

+A ₂₁a ₁₂β ³+21A ₂₂θ ^-20β ⁴

The computing formula of saturated vapour is: $X_2=I_1\mathrm{\θ}/\mathrm{\β}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\μ\β}}^{\mathrm{\μ}-1}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}-\underset{\mathrm{\μ}=6}{\overset{8}{\mathrm{\Σ}}}\frac{(\mathrm{\μ}-2){\mathrm{\β}}^{1-\mathrm{\μ}}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{\mathrm{\β}}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}}{{\{{\mathrm{\β}}^{2-\mathrm{\μ}}+\underset{\mathrm{\λ}=1}{\overset{1\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{b}_{\mathrm{\μ\λ}}{X}^{x(\mathrm{\μ},\mathrm{\λ})}\}}^2}$ $+11\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)\underset{v=0}{\overset{5}{\mathrm{\Σ}}}{B}_{9v}{X}^v$ Wherein:

X＝exp{b(1-θ} ${\mathrm{\ϵ}}_2=a_0+B_0\mathrm{\θ}-\underset{v=1}{\overset{5}{\mathrm{\Σ}}}{B}_{0v}(v-2){\mathrm{\θ}}^{v-1}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\β}}^{\mathrm{\μ}}\underset{v=i}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}(1+z(\mathrm{\μ},v)\mathrm{b\θ})}{X}^{z(\mathrm{\μ},v)}$ $+\mathrm{\β}{\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)}^{10}\underset{v=0}{\overset{6}{\mathrm{\Σ}}}\left[\right\{1+\mathrm{\θ}(\frac{10{\mathrm{\β}}_L^{\′}}{{\mathrm{\β}}_L}+\mathrm{vb})\left\}{B}_{9v}{X}^v\right]$ The assignment of each amount is as follows in above-mentioned each formula: I1=4.260321148A0=6824.687741, A1=-542.2063673, A2=-20966.66205, A3=39412.86787A4=-67332.77739, A5=99023.81028, A6=-109391.1774, A7=85908.41667A8=-45111.68742, A9=14181.38926, A10=-2017.271113, A11=7.982692717A12=-0.02616571843, A13=0.00152241179, A14=0.02284279054A15=242.1647003, A16=1.269716088E-10, A17=2.074838328E-07A18=2.17402035E-08, A19=1.105710498E-09, A20=12.93441934A21=0.00001308119072, A22=6.047626338E-14, a1=0.8438375405, a2=0.0005362162162, a3=1.72, a4=0.07342278489, a5=0.0497585887, a6=0.65371543, a7=0.00000115, a8=0.000015108, a9=0.14188, a10=7.002753165, a11=0.0002995284926, a12=0.204B0=16.83599274, B01=28.56067796, B02=-54.38923329B03=0.4330662834, B04=-0.6547711697, B05=0.08565182058B11=0.06670375918, B12=1.38983801, B21=0.08390104328B22=0.02614670893, B23=-0.03373439453, B31=0.4520918904B32=0.1069036614, B41=-0.5975336707, B42=-0.08847535804B51=0.5958051609, B52=-0.5159303373, B53=0.2075021122B61=0.1190610271, B62=-0.09867174132, B71=0.1683998803B72=-0.05809438001, B81=0.006552390126, B82=0.0005710218649B90=193.6587558, B91=-1388.522425, B92=4126.607219B93=-6508.211677, B94=5745.984054, B95=-2693.088365B96=523.5718623, b=0.7633333333, b61=0.4006073948, b71=0.08636081627b81=-0.8532322921, b82=0.3460208861n (1)=2, n (2)=3, n (3)=2, n (4)=2, n (5)=3, n (6)=2, n (7)=2n (8)=2, z (1,1)=13, z (2,1)=18, z (3,1)=18, z (4,1)=25, z (5,1)=32, z (6,1)=12, z (7,1)=24, z (8,1)=24, z (1,2)=3, z (2,2)=and 2z (3,2)=10, z (4,2)=14, z (5,2)=28, z (6,2)=11, z (7,2)=18z (8,2)=14, z (2,3)=1, z (5,3)=24,1 (6)=1,1 (7)=1,1 (8)=2, x (6,1)=14, x (7,1)=19, x (8,1)=54, x (8,2)=27k1=-7.691234564, k2=-26.08023696, k3=-168.1706546k4=64.23285504, k5=-118.9646225, k6=4.16711732k7=20.97506, k8=1.0E10, k9=9Tc=647.3K, Pc=22120000N/m ², Vc=0.00317m ³/ kgHesi=ε ₁* PcVc Hvsi=ε ₂* PcVcHvi=xi*Hvsi+ (1=xi) * Hesi=xi* ε _1i* PcVc+ (1=xi) * ε _2i* 2. PcVc calculates the feedwater enthalpy of each secondary circuit: according to formula

Calculate the steam generator inlet pressure, revise on the basis of actual measurement temperature T 1 and draw the feed temperature value, calculate the feedwater enthalpy by the ASME formula then, concrete formula is: ${\mathrm{\ϵ}}_1=a_0+A_0\mathrm{\θ}-\underset{v=1}{\overset{10}{\mathrm{\Σ}}}(v-2)A_v{\mathrm{\θ}}^{v-1}+A_{11}\left[Z\right\{17(\frac{Z}{29}-\frac{Y}{12})+5\mathrm{\θ}\frac{Y^{\′}}{12}\}+a_4\mathrm{\θ}-(a_3-1)\mathrm{\θY}{Y}^{\′}]Z^{-5/17}$ + { A ₁₂-A ₁₄θ ²+ A ₁₅(9 θ+a ₆) (a ₆-θ) ⁹+ A ₁₆(20 θ ¹⁹+ a ₇) (a ₇+ θ ¹⁹) ^-2β-(12 θ ¹¹+ a ₈) (a ₈+ θ ¹¹) ²(A ₁₇β+A ₁₈β ²+ A ₁₉β ³)+A ₂₀θ ¹⁸(17a ₉+ 19 θ ²) { (a ₁₀+ β) ³+ a ₁₁β }+A ₂₁a ₁₂β ³+ 21A ₂₂θ ^-20β ⁴Feedwater enthalpy He _i=ε _1i* PcVc

3. calculate each secondary circuit blowdown enthalpy: the blowdown enthalpy is got the enthalpy of steam generator exit saturation water, promptly

Hpi＝ε _2i*PcVc

4. calculate each secondary circuit feedwater flow, concrete formula is as follows:

Wherein: Q _EiFeedwater flow, C _EiBe efflux coefficient, E _Ei1/ (1-β _Ei ⁴) ^1/2, β _Ei=d _{E '}/ D _{E '}, d _{E '}Be the orifice plate diameter under the operating condition, d under the reference temperature _eModified value, D _{E '}For operating condition downcomer circular section diameter, be with reference to d under the humidity _eModified value, ε _eBe the expansion factor of fluid, ρ _eBe the device upstream fluid density, Δ P _eBe pressure reduction, α _eBe coefficient of flow, efflux coefficient C _eObtain by the Stolz equation: $C_e=C_{1e}+C_{2e}{\left(\frac{{10}^6}{{\mathrm{Re}}_{\mathrm{De}}}\right)}^{0.75}$ Wherein:

Be Reynolds number μ _eBe the viscosity under the operating condition, β _e=d _{E '}/ D _{E '}Be diameter ratio, L1 _eFor the orifice plate upstream face to the ratio L ' of the distance between the pressure port of upstream with pipe diameter _2eFor 5. orifice plate downstream face to the distance between the pressure port of downstream and the ratio of pipe diameter calculate the blowdown flow of each secondary circuit, the computing formula of blowdown flow is: $Q_{\mathrm{pi}}=C_{\mathrm{pi}}\·E_{\mathrm{pi}}\·{\mathrm{\ϵ}}_{\mathrm{pi}}\·{\mathrm{\πd}}_{\mathrm{pi}}^2/4\·\sqrt{2{\mathrm{\ρ}}_{\mathrm{pi}}\mathrm{\Δ}{P}_{\mathrm{pi}}}={\mathrm{\α}}_{\mathrm{pi}}\·{\mathrm{\ϵ}}_{\mathrm{pi}}\·{\mathrm{\πd}}_{\mathrm{pi}}^2/4\·\sqrt{2{\mathrm{\ρ}}_{\mathrm{pi}}\mathrm{\Δ}{P}_{\mathrm{pi}}}$ Wherein: Q _PiBe blowdown flow, C _{Pi '}Efflux coefficient, E _{A '}=1/ (1-β _Pi ⁴) ^1/2, β _Pi=d _{Pi '}/ D _{Pi '}, d _PiBeing the orifice plate diameter under the operating condition, is d under the reference temperature _PiModified value, D _{D '}For operating condition downcomer circular section diameter, be D under the reference temperature _PiModified value, ε _PiBe the expansion factor of fluid, ρ _PiBe the device upstream fluid density, Δ ρ _PiBe pressure reduction, d _PiBe coefficient of flow, efflux coefficient C _pObtain by the Stolz equation: $C_p=C_{1p}+C_{2p}{\left(\frac{{10}^6}{{\mathrm{Re}}_{\mathrm{Dp}}}\right)}^{0.75}$ Wherein:

Be Reynolds number μ _pBe the viscosity under the operating condition, β _p=d _{P '}/ D _{P '}For diameter compares L1 _pFor the orifice plate upstream face to the ratio L ' of the distance between the pressure port of upstream with pipe diameter _2pFor the orifice plate downstream face to the ratio of the distance between the pressure port of downstream with pipe diameter

6. calculate other other thermals source and pass to the heat W Δ Pr of reactor cooling system, computing formula is: the heat that the heat that heat+replenishment pump that positive energy exchange=main pump is brought into is brought into+the voltage stabilizing well heater is brought into-(heat+system's thermal loss that heat+reactor cooling system that heat+the sealing water-to-water heat exchanger is taken away of taking away of non-regenerative heat exchanger is taken away), the numerical value change of W Δ Pr is little under the nominal situation, so desirable constant, the total thermal loss value of reactor circuit is 11MW.

4) utilize the operation values of above-mentioned each secondary circuit, calculate nuclear reactor power, computing formula is: $\mathrm{WR}=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}[(\mathrm{Hvi}-\mathrm{Hei})\mathrm{Qei}-(\mathrm{Hvi}-\mathrm{Hpi})\mathrm{Qpi}]-\mathrm{W\ΔPr}$

Principle of work of the present invention is: the enthalpy liter that produces when calculating secondary circuit working medium by steam generator by measured values such as secondary circuit actuating medium temperature, pressure, flows in the steam generator in the pressurized water reactor, thereby obtain the energy that reactor-loop is passed to secondary circuit, and then the energy that a loop is obtained by other equipment and the energy consideration that loses enter, and obtains reactor core power by principle of energy balance.Specify as follows:

Heat balance method of is in measuring pressurized water reactor in the steam generator on the basis of physical parameters such as secondary circuit actuating medium temperature, pressure, flow, the enthalpy liter that produces when calculating secondary circuit working medium by steam generator, thereby obtain the energy that reactor-loop is passed to secondary circuit, and then the energy that a loop is obtained by miscellaneous equipment and the energy consideration that loses enter, and obtains the reactor core thermal power by principle of energy balance.Under steady state mode of operation, can obtain following energy-balance equation: $\mathrm{WR}=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}\mathrm{WS}{G}_i-\mathrm{W\ΔPr}----\left(1\right)$ Wherein:

WR is reactor core (NSSS) thermal power (MW)

WSGi is the thermal power (MW) that the secondary circuit actuating medium obtains in i the steam generator

W Δ Pr is the heat that other thermal source is passed to reactor cooling system in the unit interval (MW)

Formula (1) is got by the enthalpy balance relation, and promptly the heat of steam generator is provided by reactor and other thermal source, so the heat that the heat that steam generator obtains deducts other thermal source to be provided is the reactor core thermal power.

The heat that secondary circuit working medium obtains in a certain steam generator is tried to achieve by following computing formula:

WSG＝Hv?Qv+Hp?Qp-He?Qe????????????????????????????(2)

The implication of each symbol is in Qv=Qe-Qp (3) formula:

Qe is a steam generator secondary circuit feedwater flow (kg/s), Qp is a steam generator secondary circuit blowdown flow (kg/s), Qv is a steam generator secondary circuit steam flow (kg/s), He is steam generator secondary circuit feedwater enthalpy (kJ/kg), Hp is a steam generator secondary circuit blowdown enthalpy (kJ/kg), and Hv is steam generator secondary circuit outlet enthalpy of wet steam (kJ/kg).

The implication of formula (2), (3) for p.s. quality be that Qe, specific enthalpy are that the unsaturated water of He enters steam generator by steam generator secondary circuit inlet, after the steam generator heating, flow out by two outlets.One is the blowdown outlet, and the outflow mass rate is that Qp, specific enthalpy are the saturation water of Hp.Another is the wet steam outlet, and the outflow mass rate is that Qv, specific enthalpy are the wet steam of Hv.

(3) substitution (2) is obtained:

WSG＝(Hv-He)Qe-(Hv-Hp)Qp????????????????????????????(4)

The enthalpy of wet steam can be expressed as:

Hv＝x?Hvs+(1-x)Hes??????????????????????????????????(5)

X is a steam generator outlet steam quality (dimensionless)

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

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

Hvs is that the implication of enthalpy (kJ/kg) formula (5) of saturated vapour is: wet steam is made up of two parts, and a part is a saturated vapour, and the quality percentage composition is x; Another part is synthermal saturation water, and the quality percentage composition is 1-x.

(4) brought in (1) obtain: $\mathrm{WR}=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}[(\mathrm{Hvi}-\mathrm{Hei})\mathrm{Qei}-(\mathrm{Hvi}-\mathrm{Hpi})\mathrm{Qpi}]-\mathrm{W\ΔPr}----\left(6\right)$

Wet steam enthalpy Hv is determined by the pressure of steam generator steam (vapor) outlet.Suppose that the steam quality of three steam generators is identical and be constant.Pressure P is obtained through correction by measured value Pvvp, the position pressure reduction Pz that pressure loss Δ P, pressure unit and the conduit axis difference in height that correction term has dynamic pressure Pd, steam generator to be exported to pressure unit causes. Pz＝ρ′gΔz $\mathrm{\ΔP}=\mathrm{\λ}\frac{L}{D}\frac{\mathrm{\ρ}}{2}{V}^2=\mathrm{\λ}\frac{{8\mathrm{LQ}}^2}{\mathrm{\ρ}{\mathrm{\π}}^2{D}^5}$ Wherein: V is steam mean flow rate (m/s), and Q is steam mass flow (kg/s), and ρ is vapour density (kg/m ³), D is jet chimney diameter (m), and L is the length (m) that steam generator exports to the pressure unit interface, and ρ ' is the density (kg/m of water in the conduit ³), Δ z is that difference in height (m) λ between pressure unit and steam pipe axis is the coefficient of friction resistance, and is relevant with the pipeline relative roughness with Reynolds number.Therefore the steam generator top hole pressure is: $P=\mathrm{Pvvp}+{\mathrm{\ρ}}^{\′}\mathrm{g\Δz}+\frac{1}{2}{\left(\frac{4}{{\mathrm{\πD}}^2}\right)}^2\frac{Q^2}{\mathrm{\ρ}}+\mathrm{\λ}\frac{{8\mathrm{LQ}}^2}{{\mathrm{\ρ\π}}^2{D}^5}----\left(7\right)$

Obtain the pressure of steam generator outlet wet steam by following formula after, can try to achieve the enthalpy of saturation water and dry saturated steam under this pressure, obtain the enthalpy of wet steam then by dryness of wet steam by water and steam thermodynamic properties computing formula.The ASME formula that the computing formula of water and steam thermodynamic properties provides for ASME.

Water and steam is divided into four zones by temperature, pressure, and to have provided respectively be the relative pressure of independent variable, the relative algebraic expression of specific volume, relative enthalpy and relative entropy with the relative temperature to the ASME formula in each district.Owing to only use wherein a part of formula in two zones in the KME system, so only list these formula here.

Variable-definition:

Be relative pressure, Be relative temperature, Be relative specific volume,

Be relative enthalpy

P wherein _C, T _C, V _CBe the value of critical point.

When the pressure of known saturation water or saturated vapour, can iterate by following formula and try to achieve saturation temperature: $\mathrm{\β}\left(\mathrm{\θ}\right)=\exp (\frac{1}{\mathrm{\θ}}\frac{\underset{i=1}{\overset{5}{\mathrm{\Σ}}}{k}_i{(1-\mathrm{\θ})}^i}{1+k_6(1-\mathrm{\θ})+k_7{(1-\mathrm{\θ})}^2}-\frac{(1-\mathrm{\θ})}{k_8{(1-\mathrm{\θ})}^2+k_9})----\left(10\right)$

The computing formula of unsaturated water and saturation water is: x ₁=A ₁₁a ₅Z ^-5/17+ { A ₁₂+ A ₁₃θ+A ₁₄θ ²+ A ₁₅(a ₆-θ) ¹⁰+ A ₁₆(a ₇+ θ ¹⁹) ^-1}

-(a ₈+θ ¹¹) ^-1(A ₁₇+2A ₁₈β+3A ₁₉β ²)???????????????????????(11)

-A ₂₀θ ¹⁸(a ₉+θ ²){-3(a ₁₀+β) ^-4+a ₁₁}+3A ₂₁(a ₁₂-θ)β ²

+ 4A ₂₂θ ²⁰β ³Wherein:

Z＝Y+(a ₃Y ²-2a ₄θ+2a ₅β) ^1/2

Y＝1-a ₁θ ²-a ₂θ ^-6 ${\mathrm{\ϵ}}_1=a_0+A_0\mathrm{\θ}-\underset{v=1}{\overset{10}{\mathrm{\Σ}}}(v-2)A_v{\mathrm{\θ}}^{v-1}+A_{11}\left[Z\right\{17(\frac{Z}{29}-\frac{Y}{12})+5\mathrm{\θ}\frac{Y^{\′}}{12}\}+a_4\mathrm{\θ}-(a_3-1)\mathrm{\θY}{Y}^{\′}]Z^{-5/17}$

+{A ₁₂-A ₁₄θ ²+A ₁₅(9θ+a ₆)(a ₆-θ) ⁹+A ₁₆(20θ ¹⁹+a ₇)(a ₇+θ ¹⁹) ^-2}β

-(12θ ¹¹+a ₈)(a ₈+θ ¹¹) ^-2(A ₁₇β+A ₁₈β ²+A ₁₉β ³)+A ₂₀θ ¹⁸(17a ₉+19θ ²){(a ₁₀+β) ^-2+a ₁₁β}

+A ₂₁a ₁₂β ³+21A ₂₂θ ^-20β ⁴

(12)

The computing formula of saturated vapour is: $X_2=I_1\mathrm{\θ}/\mathrm{\β}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\μ\β}}^{\mathrm{\μ}-1}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}-\underset{\mathrm{\μ}=6}{\overset{8}{\mathrm{\Σ}}}\frac{(\mathrm{\μ}-2){\mathrm{\β}}^{1-\mathrm{\μ}}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{\mathrm{\β}}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}}{{\{{\mathrm{\β}}^{2-\mathrm{\μ}}+\underset{\mathrm{\λ}=1}{\overset{1\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{b}_{\mathrm{\μ\λ}}{X}^{x(\mathrm{\μ},\mathrm{\λ})}\}}^2}----\left(13\right)$ $+11\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)\underset{v=0}{\overset{5}{\mathrm{\Σ}}}{B}_{9v}{X}^v$ Wherein:

X＝exp{b(1-θ)} ${\mathrm{\ϵ}}_2=a_0+B_0\mathrm{\θ}-\underset{v=1}{\overset{5}{\mathrm{\Σ}}}{B}_{0v}(v-2){\mathrm{\θ}}^{v-1}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\β}}^{\mathrm{\μ}}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}(1+z(\mathrm{\μ},v)\mathrm{b\θ})}{X}^{z(\mathrm{\μ},v)}$

$+\mathrm{\β}{\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)}^{10}\underset{v=0}{\overset{6}{\mathrm{\Σ}}}\left[\right\{1+\mathrm{\θ}(\frac{10{\mathrm{\β}}_L^{\′}}{{\mathrm{\β}}_L}+\mathrm{vb})\left\}{B}_{9v}{X}^v\right]$

Can obtain the enthalpy that feeds water by the temperature and pressure value of measuring steam generator inflow point: when known steam generator inlet feed pressure and feed temperature, can try to achieve the enthalpy of water under this pressure and temperature by water and steam thermodynamic properties computing formula ASME formula.

Pressure can record static pressure PARE by the main feed system upstream and obtain through correction, and correction term has dynamic pressure Pd, pressure loss Δ P, position pressure reduction Pz.

Pz＝ρ′gΔz $\mathrm{\ΔP}=\mathrm{\λ}\frac{L}{D}\frac{\mathrm{\ρ}}{2}{V}^2=\mathrm{\λ}\frac{{8\mathrm{LQ}}^2}{\mathrm{\ρ}{\mathrm{\π}}^2{D}^5}$

Wherein: V is feedwater mean flow rate (m/s), and Q is feed-water quality flow (kg/s), and D is main feed system pipe diameter (m), and L is the length (m) of inlet from the main feed system to the steam generator, and ρ ' is the density (kg/m of water in the transmitter conduit ³), Δ z is the difference in height (m) of pressure unit and feed pipe between centers, λ is the coefficient of friction resistance, and is relevant with the pipeline relative roughness with Reynolds number.

Therefore the steam generator inlet pressure is: $P=P_{\mathrm{ARE}}+{\mathrm{\ρ}}^{\′}\mathrm{g\Δz}+\frac{1}{2}{\left(\frac{4}{{\mathrm{\πD}}^2}\right)}^2\frac{Q^2}{\mathrm{\ρ}}-\mathrm{\λ}\frac{{8\mathrm{LQ}}^2}{{\mathrm{\ρ\π}}^2{D}^5}----\left(15\right)$

On the basis of measured temperature, consider that the main feed system pipeline to the thermal loss between the steam generator inlet, can obtain the feed temperature value.Thermal loss numerical value is amassed by the coefficient of heat transfer and pipe surface and calculates.

The blowdown enthalpy is got the enthalpy of steam generator exit saturation water.The computing method of enthalpy are with reference to the computing method of wet steam enthalpy, and pressure is the vapor pressure that measures.

Feedwater flow Qe is measured by orifice flowmeter, and according to the relevant regulations of international standard ISO5167-1-92 (alternate standard of NFX10-102), fluid pressure difference and fluid density are calculated feedwater flow by density and differential manometer before and after the measuring diaphragm.

Fluid density is obtained by pressure and temperature.Consider the orifice plate sectional area, can obtain the computing formula of fluid flow: $Q=C\·E\·\mathrm{\ϵ}\·{\mathrm{\πd}}^2/4\·\sqrt{2\mathrm{\ρ\ΔP}}=\mathrm{\α}\·\mathrm{\ϵ}\·{\mathrm{\πd}}^2/4\·\sqrt{2\mathrm{\ρ\ΔP}}----\left(16\right)$ Wherein: Q is flow (kg/s), and C is efflux coefficient (dimensionless), and this coefficient obtains according to the NFX10-102 criterion calculation.E is progressive velocity coefficient (dimensionless), E=1/ (1-β ⁴) ^1/2Wherein: β be diameter than (dimensionless), β=d/D, d are the orifice plate diameter (m) under the operating condition, D is an operating condition downcomer circular section diameter (m), ε is the expansion factor (dimensionless) of fluid, incompressible fluid ε=1.ρ is device upstream fluid density (kg/m ³), Δ P is pressure reduction (Pa), α is that coefficient of flow (dimensionless) efflux coefficient C is obtained promptly by the Stolz equation

Wherein:

C ₂=0.0029 β ²⁵, Be Reynolds number

μ is the viscosity (kg/s.m) under the operating condition, and β=d/D is the diameter ratio, and L1 is that the orifice plate upstream face is to the ratio of the distance between the pressure port of upstream with pipe diameter, L ₂For the orifice plate downstream face to the ratio of the distance between the pressure port of downstream with pipe diameter

The computing method of blowdown flow are identical with the computing method of feedwater flow, do not repeat them here.

Other thermal source is transferred to the thermal power (W Δ Pr) of reactor cooling system:

The heat of input has: the heat that the heat that the heat that main pump is brought into, replenishment pump are brought into, voltage stabilizing well heater are brought into.The heat of output has: the heat that the heat that non-regenerative heat exchanger is taken away, sealing water-to-water heat exchanger are taken away, heat, the system's thermal loss that reactor cooling system is taken away.

More than every heat can try to achieve by energy budget method according to the ruuning situation of relevant devices.Concrete grammar is: obtained the intake of relevant devices and exported energy by pressure, temperature and flow measurements, the difference of the two is the energy that exchanges between this equipment and the steam generator.Numerical value change is little under the nominal situation, so desirable constant.Be taken as 11MW according in the past three total thermal loss in loop of operating experience.

Advantage of the present invention is: by measuring the enthalpy liter that produces when measured values such as secondary circuit actuating medium temperature, pressure, flow calculate secondary circuit working medium by steam generator in the steam generator in the pressurized water reactor, thereby obtain the energy that reactor-loop is passed to secondary circuit, and then the energy that a loop is obtained by other equipment and the energy consideration that loses enter, and calculates reactor core power by principle of energy balance.Therefore, can improve power measurement speed and accuracy greatly, improve the economic benefit of nuclear power station unit operation.

The present invention is further illustrated below in conjunction with drawings and Examples.

Fig. 1 is pressurized water reactor of the present invention one loop and secondary circuit structural representation

Fig. 2 is that measurements and calculations equipment of the present invention connects block diagram;

Fig. 3 is an executive routine logic diagram of the present invention.

Among Fig. 1, pressurized water reactor one loop and secondary circuit connect each other by steam generator.

Among Fig. 2, handle PC and be connected with the data acquisition PC, the data acquisition PC is connected with the isolation acquisition module, isolates acquisition module and is connected with the in-site measurement signal wire.

Among Fig. 3, the constant parameter is input to the processing PC, after the processing PC powers up and brings into operation, handling PC utilizes momentum parameter and constant parameter to calculate, the feedwater flow, blowdown flow, steam flow, feedwater enthalpy, blowdown enthalpy, outlet enthalpy of wet steam and other thermals source that calculate each secondary circuit of steam generator are passed to the heat of reactor cooling system, calculate pressurized-water reactor core power at last.

In order to verify the measurement effect of above-mentioned measuring method, to calculate by the real time data of GNPS, result of calculation is as shown in the table:

Thermal power calculated value (MW)	260、5	?509、8	1380、1	?1727、0	?2121、8
						Thermal power actual value (MW)	260、8	?510、8	1381、4	?1728、6	?2123、6
The thermal power error of calculation (MW)	-0、3	?-0、5	-1、3	?-1、6	?-1、8
						Thermal power calculated value (MW)	2359、4	?2428、5	2544、0	?2882、8	?2899、1
Thermal power actual value (MW)	2361、4	?2430、6	2546、2	?2885、4	?2901、7
						The thermal power error of calculation (MW)	-2、0	?-2、1	-2、2	?-2、6	?-2、6

Last table result of calculation shows: nuclear reactor core power calculation value and actual value that this kind measuring method obtains differ very little, and maximum absolute error is 2,6MW, 1% of not enough full scale.

Claims (1)

1, a kind of method for measuring power of pressurized-water reactor core for nuclear power station is characterized in that:

(1) will handle PC and be connected with the data acquisition PC, the data acquisition PC is connected with the isolation acquisition module, isolates acquisition module and is connected with the in-site measurement signal wire;

(2) gather correlation parameter by isolating acquisition module, and the parameter that collects is input to acquisition PC machine, utilize the data of acquisition PC machine, the program by in the operation processing PC just can obtain reactor core power, and its concrete steps are:

1) the constant data that need in the time of will measuring are input to be handled in the PC, these data comprise: 1. jet chimney diameter D, steam generator export to the length L of pressure unit interface under the reference temperature, difference in height Δ z between pressure unit and steam pipe axis, coefficient of friction resistance λ, 2. main feed system pipe diameter D under the reference temperature ₁, the length L of inlet from the main feed system to the steam generator ₁, the difference in height Δ z of pressure unit and feed pipe between centers ₁, coefficient of friction resistance λ ₁, the 3. feedwater orifice plate diameter d under the reference temperature _e, give water conduit circular section diameter D under the reference temperature _e, the 4. mudhole board diameter d under the reference temperature _p, reference temperature down blow conduit circular section diameter D _p

2) calculate momentum parameter by isolating the acquisition module collection, these data comprise: 1. steam generator top hole pressure P _Vvp, steam mean flow rate V, steam generator outlet steam quality x is steam generator inlet pressure P 2. _Are, the pressure differential deltap that 3. feeds water Pel, 4. blowdown pressure differential deltap P _Pl

3) handling PC utilizes momentum parameter and constant parameter to calculate, the feedwater flow, blowdown flow, steam flow, feedwater enthalpy, blowdown enthalpy, outlet enthalpy of wet steam and other thermals source that calculate each secondary circuit of steam generator are passed to the heat of reactor cooling system, and the concrete operation way is:

1. calculate each secondary circuit enthalpy of wet steam: according to formula

Calculate the steam generator top hole pressure, according to this pressure value, calculate the enthalpy of saturation water and saturated dry steam under this pressure by the ASME formula, obtain the enthalpy of wet steam again according to the mass dryness fraction of wet steam, concrete computing formula is as follows;

Be relative pressure,

Be relative temperature, Be relative specific volume,

Be relative enthalpy, wherein P _C, T _C, V _CBe the value of critical point, when the pressure of known saturation water or saturated vapour, can iterate by following formula and try to achieve saturation temperature: $\mathrm{\β}\left(\mathrm{\θ}\right)=\exp (\frac{1}{\mathrm{\θ}}\frac{\underset{i=1}{\overset{5}{\mathrm{\Σ}}}{k}_i{(1-\mathrm{\θ})}^i}{1+k_6(1-\mathrm{\θ})+k_7{(1-\mathrm{\θ})}^2}-\frac{(1-\mathrm{\θ})}{k_8{(1-\mathrm{\θ})}^2+k_9})$ The computing formula of unsaturated water and saturation water is: x ₁=A ₁₁a ₅Z ^-5/17+ { A ₁₂+ A ₁₃θ+A ₁₄θ ²+ A ₁₅(a ₆-θ) ¹⁰+ A ₁₆(a ₇+ θ ¹⁹) ^-1}

-(a ₈+θ ¹¹) ^-1(A ₁₇+2A ₁₈β+3A ₁₉β ²)

-A ₂₀θ ¹⁸(a ₉+θ ²){-3(a ₁₀+β) ^-4+a ₁₁}+3A ₂₁(a ₁₂-θ)β ²

+ 4A ₂₂θ ^-20β ³Wherein:

Z＝Y+(a ₃Y ²-2a ₄θ+2a ₅β) ^1/2

Y＝1-a ₁θ ²-a ₂θ ^-6 ${\mathrm{\ϵ}}_1=a_0+A_0\mathrm{\θ}-\underset{v=1}{\overset{10}{\mathrm{\Σ}}}(v-2)A_v{\mathrm{\θ}}^{v-1}+A_{11}\left[Z\right\{17(\frac{Z}{29}-\frac{Y}{12})+5\mathrm{\θ}\frac{Y^{\′}}{12}\}+a_4\mathrm{\θ}-(a_3-1)\mathrm{\θY}{Y}^{\′}]Z^{-5/17}$

+{A ₁₂-A ₁₄θ ²+A ₁₅(9θ+a ₆)(a ₆-θ) ⁹+A ₁₆(20θ ¹⁹+a ₇)(a ₇+θ ¹⁹) ^-2}β

-(12θ ¹¹+a ₈)(a ₈+θ ¹¹) ^-2(A ₁₇β+A ₁₈β ²+A ₁₉β ³)+A ₂₀θ ¹⁸(17a ₉+19θ ²){(a ₁₀+β) ^-3+a ₁₁β}

+ A ₂₁a ₁₂β ³+ 21A ₂₂θ ^-20β ⁴The computing formula of saturated vapour is: $X_2=I_1\mathrm{\θ}/\mathrm{\β}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\μ\β}}^{\mathrm{\μ}-1}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}-\underset{\mathrm{\μ}=6}{\overset{8}{\mathrm{\Σ}}}\frac{(\mathrm{\μ}-2){\mathrm{\β}}^{1-\mathrm{\μ}}\underset{v=1}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{\mathrm{\β}}_{\mathrm{\μv}}{X}^{z(\mathrm{\μ},v)}}{{\{{\mathrm{\β}}^{2-\mathrm{\μ}}+\underset{\mathrm{\λ}=1}{\overset{1\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{b}_{\mathrm{\μ\λ}}{X}^{x(\mathrm{\μ},\mathrm{\λ})}\}}^2}$ $+11\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)\underset{v=0}{\overset{5}{\mathrm{\Σ}}}{B}_{9v}{X}^v$ Wherein:

X＝exp{b(1-θ)} ${\mathrm{\ϵ}}_2=a_0+B_0\mathrm{\θ}-\underset{v=1}{\overset{5}{\mathrm{\Σ}}}{B}_{0v}(v-2){\mathrm{\θ}}^{v-1}-\underset{\mathrm{\μ}=1}{\overset{5}{\mathrm{\Σ}}}{\mathrm{\β}}^{\mathrm{\μ}}\underset{v=i}{\overset{n\left(\mathrm{\μ}\right)}{\mathrm{\Σ}}}{B}_{\mathrm{\μv}(1+z(\mathrm{\μ},v)\mathrm{b\θ})}{X}^{z(\mathrm{\μ},v)}$

$+\mathrm{\β}{\left(\frac{\mathrm{\β}}{{\mathrm{\β}}_L}\right)}^{10}\underset{v=0}{\overset{6}{\mathrm{\Σ}}}\left[\right\{1+\mathrm{\θ}(\frac{10{\mathrm{\β}}_L^{\′}}{{\mathrm{\β}}_L}+\mathrm{vb})\left\}{B}_{9v}{X}^v\right]$ The assignment of each amount is as follows in above-mentioned each formula: I1=4.260321148A0=6824.687741, A1=-542.2063673, A2=-20966.66205, A3=39412.86787A4=-67332.77739, A5=99023.81028, A6=-109391.1774, A7=85908.41667A8=-45111.68742, A9=14181.38926, A10=-2017.271113, A11=7.982692717A12=-0.02616571843, A13=0.00152241179, A14=0.02284279054A15=242.1647003, A16=1.269716088E-10, A17=2.074838328E-07A18=2.17402035E-08, A19=1.105710498E-09, A20=12.93441934A21=0.00001308119072, A22=6.047626338E-14, a1=0.8438375405, a2=0.0005362162162, a3=1.72, a4=0.07342278489, a5=0.0497585887, a6=0.65371543, a7=0.00000115, a8=0.000015108, a9=0.14188, a10=7.002753165, a11=0.0002995284926, a12=0.204B0=16.83599274, B01=28.56067796, B02=-54.38923329B03=0.4330662834, B04=-0.6547711697, B05=0.08565182058B11=0.06670375918, B12=1.388983801, B21=0.08390104328B22=0.02614670893, B23=-0.03373439453, B31=0.4520918904B32=0.1069036614, B41=-0.5975336707, B42=-0.08847535804B51=0.5958051609, B52=-0.5159303373, B53=0.2075021122B61=0.1190610271, B62=-0.09867174132, B71=0.1683998803B72=-0.05809438001, B81=0.006552390126, B82=0.0005710218649B90=193.6587558, B91=-1388.522425, B92=4126.607219B93=-6508.211677, B94=5745.984054, B95=-2693.088365B96=523.5718623, b=0.7633333333, b61=0.4006073948, b71=0.08636081627b81=-0.8532322921, b82=0.3460208861n (1)=2, n (2)=3, n (3)=2, n (4)=2, n (5)=3, n (6)=2, n (7)=2n (8)=2, z (1,1)=13, z (2,1)=18, z (3,1)=18, z (4,1)=25, z (5,1)=32, z (6,1)=12, z (7,1)=24, z (8,1)=24, z (1,2)=3, z (2,2)=and 2z (3,2)=10, z (4,2)=14, z (5,2)=28, z (6,2)=11, z (7,2)=18z (8,2)=14, z (2,3)=1, z (5,3)=24,1 (6)=1,1 (7)=1,1 (8)=2, x (6,1)=14, x (7,1)=19, x (8,1)=54, x (8,2)=27k1=-7.691234564, k2=-26.08023696, k3=-168.1706546k4=64.23285504, k5=-118.9646225, k6=4.16711732k7=20.97506, k8=1.0E10, k9=9Tc=647.3K, Pc=22120000N/m ², Vc=0.00317m ³/ kgHesi=ε ₁* PcVc Hvsi=ε ₂* PcVcHvi=xi*Hvsi+ (1-xi) * Hesi=xi* ε _Ii* PcVc+ (1-xi) * ε _2i* 2. PcVc calculates the feedwater enthalpy of each secondary circuit: according to formula

Calculate the steam generator inlet pressure, revise on the basis of actual measurement temperature T 1 and draw the feed temperature value, calculate the feedwater enthalpy by the ASME formula then, concrete formula is: ${\mathrm{\ϵ}}_1=a_0+A_0\mathrm{\θ}-\underset{v=1}{\overset{10}{\mathrm{\Σ}}}(v-2)A_v{\mathrm{\θ}}^{v-1}+A_{11}\left[Z\right\{17(\frac{Z}{29}-\frac{Y}{12})+5\mathrm{\θ}\frac{Y^{\′}}{12}\}+a_4\mathrm{\θ}-(a_3-1)\mathrm{\θY}{Y}^{\′}]Z^{-5/17}$

+{A ₁₂-A ₁₄θ ²+A ₁₅(9θ+a ₆)(a ₆-θ) ⁹+A ₁₆(20θ ¹⁹+a ₇)(a ₇+θ ¹⁹) ^-2}β

-(12θ ¹¹+a ₈)(a ₈+θ ¹¹) ^-2(A ₁₇β+A ₁₈β ²+A ₁₉β ³)+A ₂₀θ ¹⁸(17a ₉+19θ ²){(a ₁₀+β) ^-3+a ₁₁β}

+ A ₂₁a ₁₂β ³+ 21A ₂₂θ ^-20β ⁴Feedwater enthalpy He _i=ε _1i* 3. PcVc calculates each secondary circuit blowdown enthalpy: the blowdown enthalpy is got the enthalpy of steam generator exit saturation water, i.e. Hpi=ε _2i* 4. PcVc calculates each secondary circuit feedwater flow, and concrete formula is as follows:

Wherein: Q _EiFeedwater flow, c _EiBe efflux coefficient, E=1/ (1-β _Ei ⁴) ^1/2, β _r=d _{E '}/ D _{E '}, d _{E '}Be the orifice plate diameter under the operating condition, d under the reference temperature _eModified value, D _eFor operating condition downcomer circular section diameter, be d under the reference temperature _eModified value, ε _eBe the expansion factor of fluid, σ _eBe the device upstream fluid density, Δ P _eBe pressure reduction, α _eBe coefficient of flow, efflux coefficient C _eObtain by the Stolz equation: $C_e=C_{1e}+C_{2e}{\left(\frac{{10}^6}{{\mathrm{Re}}_{\mathrm{De}}}\right)}^{0.75}$ Wherein:

C _2e=0.0029 β ^2.5,

Be Reynolds number μ _gBe the viscosity under the operating condition, β _e=d _{E '}/ D _{E '}Be diameter ratio, L1 _eFor the orifice plate upstream face to the ratio L of the distance between the pressure port of upstream with pipe diameter _2e ^'For 5. orifice plate downstream face to the distance between the pressure port of downstream and the ratio of pipe diameter calculate the blowdown flow of each secondary circuit, the computing formula of blowdown flow is: $Q_{\mathrm{pi}}=C_{\mathrm{pi}}\·E_{\mathrm{pi}}\·{\mathrm{\ϵ}}_{\mathrm{pi}}\·{\mathrm{\πd}}_{\mathrm{pi}}^2/4\·\sqrt{2{\mathrm{\ρ}}_{\mathrm{pi}}\mathrm{\Δ}{P}_{\mathrm{pi}}}={\mathrm{\α}}_{\mathrm{pi}}\·{\mathrm{\ϵ}}_{\mathrm{pi}}\·{\mathrm{\πd}}_{\mathrm{pi}}^2/4\·\sqrt{2{\mathrm{\ρ}}_{\mathrm{pi}}\mathrm{\Δ}{P}_{\mathrm{pi}}}$ Wherein: Q _PiBe blowdown flow, Q _PiBe efflux coefficient, E _Pi=1/ (1-β _Ii ⁴) ^1/2, β _p=d _{Pi '}/ D _{Pi '}, d _PiBeing the orifice plate diameter under the operating condition, is d under the reference temperature _{Pi '}Modified value, D _PiFor operating condition downcomer circular section diameter, be D under the reference temperature _PiModified value, ε _{Pi '}Be the expansion factor of fluid, ρ _{Pi '}Be the device upstream fluid density, Δ P _{Pi '}Be pressure reduction, σ _PiBe coefficient of flow, efflux coefficient C _pObtain by the Stolz equation: $C_p=C_{1p}+C_{2p}{\left(\frac{{10}^6}{{\mathrm{Re}}_{\mathrm{Dp}}}\right)}^{0.75}$ Wherein:

Be Reynolds number μ _pBe the viscosity under the operating condition, β _p=d _{P '}/ D _{P '}For diameter compares L1 _pFor the orifice plate upstream face to the ratio L of the distance between the pressure port of upstream with pipe diameter _2p ^'For the orifice plate downstream face to the ratio of the distance between the pressure port of downstream with pipe diameter

6. calculate other other thermals source and pass to the heat W Δ Pr of reactor cooling system, computing formula is: the heat that the heat that heat+replenishment pump that positive energy exchange=main pump is brought into is brought into+the voltage stabilizing well heater is brought into-(heat+system's thermal loss that heat+reactor cooling system that heat+the sealing water-to-water heat exchanger is taken away of taking away of non-regenerative heat exchanger is taken away), the numerical value change of W Δ Pr is little under the nominal situation, so desirable constant, the total thermal loss value of reactor circuit is 11MW.4) utilize the operation values of above-mentioned each secondary circuit, calculate nuclear reactor power, computing formula is: $\mathrm{WR}=\underset{i=1}{\overset{3}{\mathrm{\Σ}}}[(\mathrm{Hvi}-\mathrm{Hei})\mathrm{Qei}-(\mathrm{Hvi}-\mathrm{Hpi})\mathrm{Qpi}]-\mathrm{W\ΔPr}$

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