Open joint-stock company«All-Russian Research and Design-Engineering Institute of

nuclear power machine building» JSC «VNIIAM»

7-th International Scientific and Technical Conference «Safety, efficiency and economics of nuclear power»

MNTK-2010

A.A.AvdeevDirector General, Doctor of Technical Sciences

SECONDARY CIRCUIT HEAT-EXCHANGE EQUIPMENT EFFICIENCY IMPROVEMENT

Moscow, 26-27 May 2010 JSC «Concern Rosenergoatom»

Efficiency

>98% 33÷36%

Reactor island Turbine island

Almost all heat released in the core is supplied to secondary circuit

Only the third part of heat is converted to electric power

Today, technical problems center of gravity is in the turbine hall

Economics evaluation

How much higher can the cost of the turbine plant with efficiency increased by 1% be?

Capital expenditure to produce this power

Unit 1200 МW; Efficiency э = 36%Additional production: 33,3 МW

3000 €/kW * 33,3 МW = 100 mln.€

э = 37%

Account is not taken of «small things»: fuel saving, specific operating expenses, etc.

Note: cost of 1000 МW turbine (Kharkov): about 80 mln. € cost of 1200 МW 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 all the kit of turbine hall components.

Effect of turbine plant К-1000-60/1500 parameters on electric power underproduction

It no.

Name of parameterRated

(calculated) value

DeviationLoss of power,

МW

1. Live steam degree of dryness, % 99,5 -0,5 -3,5

2. Spent steam pressure kgf/cm2, (kPa)

0,05 (5,0) +0,01 (1,0) -11,5

3. Pressure losses in steam-admission devices (SCV), %

3÷4 +1,0 -1,5÷-2,0

4. Pressure losses in intermediate overheating components (MSR), %

7,0 +1,0 -2,0

5. Feed water final temperature, С 220,0 -5,0 -3,0

6. Steam underheating, in MSR I-st and II-d stages, С

25,0 +5,0 -0,5÷-1,0

Total: 23 МW

Parameters optimization

The optimization 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 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 results

1. Normalization

2. Identification and elimination of losses

3. Assessment of upgrading results

Electric power of NPP unit depending on the temperature of the incoming cooling water (under nominal power)

Un

it po

wer

Pressu

re of th

e used

steam in

the co

nd

enser

NPP (Power Unit) turbine plant testsNPP

Power Unit No.Turbine Test year and performer

Type Manufacturer

Leningrad NPP, Unit1 К-500-60/3000 Turboatom 1976 ; ОRGRES, Ural Division

ChNPP, Unit 1 К-500-60/3000 Turboatom 1980; ОRGRES, South Division

Kalinine NPP, Unit 1 К-1000-60/1500 Turboatom 1985; ОRGRES, Мoscow

Kalinine NPP, Unit 2 К-1000-60/1500 Turboatom 1986; ОRGRES, Моscow

VVER-1000 Power Units with К-1000-60/1500-2-type turbines (Тurboatom, with basement-type condensers) are installed at Balakovo NPP (Units № 1÷4) and Rostov NPP (Units 1, 2). No thermal tests were performed at either of the Units.

Vacuum effect on power generation

Positive effect Negative effect

• increase in available heat drop • steam output reduction due to

condensate cooling;• increase in losses with outlet velocity;• oi reduction of last stages;• increase in steam extraction to LPH

Efficient vacuum

Electric power consumption by circulation pumps Nц 70÷80*Nс.н

Nц Wох3

Power

Auxiliaries

Underproduction

Cooling water flow rate

Determination of cooling water optimum flow rate

1. Low heat exchange intensity 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 70ºС;4.Low reliability due to thermo-hydraulic instability;5. In case of tube loss of tightness, one cassette is plugged;6. Low maintainability, in particular, for low tier of heat-exchange cassettes;7. Complex MSR pipe connections;8. Large dimensions: MSR and и heated steam pipelines are located above the turbine servicing level.9. Untransportable by railway.10.MSR assembly during installation.11.High metal intensity and 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: 208х4=832t;

2. Metal overexpenditure per Unit: 384t;

3. MSR is equipped with 4 offset condensate collectors;

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. Pipelines 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: 112х4=448t;

2.Metal saving per Unit: 384t;

3. 4 condensate collectors are excluded 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 0,4МW due to condensate 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 characteristics 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 Powersep

Turbulence chamber

Turbulence chamber Condensate collection chamber

A = wet steam with x – 13 %

B = Water removal

C = dry steam

Inter-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 up to 2 %•Increases overheating by 8-10 К

The steam inter-receiver separation system developed by JSC «VNIIAM» has been in operation at Kola NPP since the early 1990-ies and is designed for preliminary drying of moist steam coming from high pressure cylinder to

moisture separator-reheater (MSR)

Separate

From high pressure cylinder

Film-type separator

Bow-type separator

Special blades

To SRS

Receiver of Kola NPP turbine К-220 with blades

Thank you for your attention

Our coordinates:125171 Moscow, Cosmonaut Volkov street, 6АPhone: 8 (499)150-83-35; 8 (499)150-83-36Fax: 8 (499)159-94-74www.vniiam.ruJSC «All-Russian Research and Design-Engineering Institute of nuclear power machine building» (JSC «VNIIAM»)