核电站二次回路热交换设备效率改善

1、Open joint-stock companyAll-Russian Research and Design-Engineering Institute of nuclear power machine building JSC VNIIAM7-th International Scientific and Technical Conference Safety, efficiency and economics of nuclear power MNTK-2010A.A.AvdeevDirector General, Doctor of Technical SciencesSECONDAR

2、Y CIRCUIT HEAT-EXCHANGE EQUIPMENT EFFICIENCY IMPROVEMENTMoscow, 26-27 May 2010 JSC Concern RosenergoatomEfficiency98%3336%Reactor islandTurbine islandAlmost all heat released in the core is supplied to secondary circuitOnly the third part of heat is converted to electric powerToday, technical proble

3、ms center of gravity is in the turbine hallEconomics evaluationHow much higher can the cost of the turbine plant with efficiency increased by 1% be?Capital expenditure to produce this powerUnit 1200 W; Efficiency = 36%Additional production: 33,3 W3000 /kW * 33,3 W = 100 mln. = 37%Account is not take

4、n of small things: fuel saving, specific operating expenses, etc.Note: cost of 1000 W turbine (Kharkov): about 80 mln. cost of 1200 W turbine (St.Pb): about 100 mln. It is more profitable to pay twice more for the turbine with efficiency increased by 1%. The turbine plant efficiency is determined by

5、 all the kit of turbine hall components.Effect of turbine plant -1000-60/1500 parameters on electric power underproductionIt no.Name of parameterRated (calculated) valueDeviationLoss of power, W1.Live steam degree of dryness, %99,5-0,5-3,52.Spent steam pressure kgf/cm2, (kPa)0,05 (5,0)+0,01 (1,0)-11

6、,53.Pressure losses in steam-admission devices (SCV), %34+1,0-1,5-2,04.Pressure losses in intermediate overheating components (MSR), %7,0+1,0-2,05.Feed water final temperature, 220,0-5,0-3,06.Steam underheating, in MSR I-st and II-d stages, 25,0+5,0-0,5-1,0Total:23 WParameters optimizationThe optimi

7、zation of turbine plant parameters requires: Unit heat losses tests within the range of loads from 75 to100% from rated power; condenser thermal tests with building of vacuum dependency on cooling water flow rate and temperature; turbine power experimental corrections in case of changes in condenser

8、 spent steam pressure.Heat losses tests are conducted according to the first category of complexity with arranging additional inserts and applying the state-of-the-art fleet of high accuracy instruments.Test results1. Normalization2. Identification and elimination of losses3. Assessment of upgrading

9、 resultsElectric power of NPP unit depending on the temperature of the incoming cooling water (under nominal power)Unit powerPressure of the used steam in the condenserNPP (Power Unit) turbine plant testsNPPPower Unit No.TurbineTest year and performerTypeManufacturerLeningrad NPP, Unit1-500-60/3000T

10、urboatom1976 ; RGRES, Ural DivisionChNPP, Unit 1-500-60/3000Turboatom1980; RGRES, South DivisionKalinine NPP, Unit 1-1000-60/1500Turboatom1985; RGRES, oscowKalinine NPP, Unit 2-1000-60/1500Turboatom1986; RGRES, scow VVER-1000 Power Units with -1000-60/1500-2-type turbines (urboatom, with basement-ty

11、pe condensers) are installed at Balakovo NPP (Units 14) and Rostov NPP (Units 1, 2). No thermal tests were performed at either of the Units.Vacuum effect on power generationPositive effectNegative effect increase in available heat drop steam output reduction due to condensate cooling; increase in lo

12、sses with outlet velocity; oi reduction of last stages; increase in steam extraction to LPHEfficient vacuum Electric power consumption by circulation pumps N 7080*N. N W3PowerAuxiliariesUnderproductionCooling water flow rateDetermination of cooling water optimum flow rate 1. Low heat exchange intens

13、ity due to longitudinal tube ribbing;2. There are conditions for non-condensable gases accumulation in tubes;3. There is thermo-hydraulic instability. Temperature pulsations reach 70;4.Low reliability due to thermo-hydraulic instability;5. In case of tube loss of tightness, one cassette is plugged;6

14、. Low maintainability, in particular, for low tier of heat-exchange cassettes;7. Complex MSR pipe connections;8. Large dimensions: MSR and heated steam pipelines are located above the turbine servicing level.9. Untransportable by railway.10.MSR assembly during installation.11.High metal intensity an

15、d high cost.Design deficiencies of double-stage cassete-type separator-steam reheater:Comparison of double-stage cassette-type and collector-platen type MSR (NPP-2006)Cassette-type1. MSR mass per Unit: 2084=832t;2. Metal overexpenditure per Unit: 384t;3. MSR is equipped with 4 offset condensate coll

16、ectors;4. Four pipelines for heating steam, condensate and equalizing lines per each overheating stage;5. 1% of the surface is plugged in case of 1 tube leak;6. Overhaul of tube bundles is required; 7. It is constructively impossible to cool heating steam condensate;8. MSR height: 21,45m;9. Pipeline

17、s occupy the area equal to that of the turbine, turbine hall increase by 9 m is required;10. Condensate discharge at saturation temperature reduces valve and pipeline service life.Collector-platen type1. MSR mass per Unit: 1124=448t;2.Metal saving per Unit: 384t;3. 4 condensate collectors are exclud

18、ed from MSR complete set;4. One pipeline for heating steam, condensate and equalizing lines per each overheating stage;5. 0,02% of the surface is plugged in case of 1 tube leak;6. Overhaul of tube bundles is not required over the operation period;7. Increase in turbine plant power by 0,4W due to con

19、densate cooling in intermediate overheating first stage;8.MSR height: 13,51m (1.6 times smaller);9. Pipelines and MSR are located under turbine servicing platform;10. Increase in operational reliability of cooled condensate discharge valves and pipelines;11. Reduction of mass dimensions characterist

20、ics of PBD-Sh No.5 (due to cooled condensate dump to deaerator);12. MSR cost per Unit is lower by 46%. Inter-receiver separator Powersep (BALCKE DURR)Flow chart of PowersepTurbulence chamberTurbulence chamberCondensate collection chamberA = wet steam with x 13 %B = Water removalC = dry steamInter-receiver separation system Consists of a film separator and two elbow separators sequentially installed according to steam stream in turbine plant receivers, separated water flow rate: 102 m3/h separation efficiency: 83% dries moist steam