ALSTOM WORLD WIDE EXPERIENCE OF STEAM TURBINE RETROFITS ON NUCLEAR POWER PLANTS. May 2015

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Diana Morton
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1 ALSTOM WORLD WIDE EXPERIENCE OF STEAM TURBINE RETROFITS ON NUCLEAR POWER PLANTS May 2015

2 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

3 Alstom Nuclear References

4 Introduction - Experience Alstom is the number one global supplier of nuclear steam turbines. 181 nuclear steam turbines supplied 50 Hz and 60 Hz grids all types of reactors: PWR, BWR, PHWR, Magnox, etc... 30% of the world nuclear fleet operates with Alstom turbines & generators 240 nuclear turbine cylinders retrofitted/on order 30% are HP cylinders 70% are LP cylinders 89 non-oem nuclear turbine cylinders retrofitted/on order Extensive Nuclear Retrofit Experience

5 Introduction - Global Footprint Tendering & Order Execution Centres are based in: Richmond, USA, Elblag, Poland Delhi, India, Rugby, UK Beijing, China, Mannheim, Germany Localised Sales and Project Management Offices in all major market regions (Richmond, USA) Global manufacturing footprint

6 Main drivers for retrofitting nuclear LP & HP turbines: Replace problematic LP & HP rotors with modern technology Obtain additional MW output for the same reactor power Improved technology blading Optimised exhaust area Extended power up-rate with increased steam flow Address end-loading limits on existing LP s Reduce maintenance costs, extend inspection intervals Life extension associated with a plant license extension

7 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

technology technology capabilities, capabilities,

8 Alstom s Steam Turbine Fleet Impulse Reaction Alstom s unique, unique very powerful Steam Turbine ST technology technology capabilities, capabilities, covering both covering both reaction reaction and impulse and impulse.

Steam Path Technology Alstom has Impulse

Reaction Technology (RTB) 50% reaction =

reaction = 90% pressure drop across fixed

9 Steam Path Technology Alstom has Impulse & Reaction Technology available. Reaction Technology (RTB) 50% reaction = 50% pressure drop across fixed & 50% across moving blades Drum rotor construction Impulse Technology (ITB) 10% reaction = 90% pressure drop across fixed & 10% across moving blades Disk and Diaphragm construction Robust control stage Alternate torsion design Extensive experience 30 years without incident

rigid and continuous shroud No special closing blade Benefits High stage efficiency Robust proven

10 Steam Path Technology Reaction Blading Technology (ITB) Typical stationary blade Typical rotating blade Features Standard blading since D aerofoils, integral shrouds Pre-twisted blades with rigid and continuous shroud No special closing blade Benefits High stage efficiency Robust proven design Not sensitive to vibrations or flow changes Easy replacement and re-installation Low maintenance costs

11 Steam Path Technology Technology selected to give maximum benefit: Nuclear LP Retrofits Reaction technology normally selected (best performance/cost ratio) Nuclear HP Retrofits Technology selected on case by case basis Alstom LP Blading - Selection of L-0 Blade Length Exhaust area (L-0 blade length) has a significant effect on performance of LP turbines and the output of the unit L-0 blade length should be selected based on the condenser vacuum through the year (not just original heat balance value) Units with low average backpressure can often achieve significantly higher output from a longer L-0 blade Alstom has a broad range of applicable L-0 blades

12 Optimise L-0 Diffuser Optimise L-0 diffuser design by 3D CFD to minimise exhaust loss Model includes support and stiffening plates that affect flow distribution

13 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

LP Rotor Technology Welded Rotors used for all Alstom 1800

of suppliers -Small forgings have better metallurgical

forging can be selected to maximise SCC resistance -Forgings

14 LP Rotor Technology Welded Rotors used for all Alstom 1800 rpm LP Retrofits -Small forgings obtained from a wide range of suppliers -Small forgings have better metallurgical properties and are easier to inspect -Strength level of each forging can be selected to maximise SCC resistance -Forgings welded together using a combination of argon arc and submerged arc welding

15 Rotor Technology Welded Rotor Experience Well established technology : Used by ALSTOM POWER since the 1920 s Applied on nuclear turbine rotors since 1965 More than 5000 welded rotors supplied for steam and gas turbines Stress Corrosion Cracking (SCC) Historical Development SCC has been recognized as a problem in nuclear turbine rotors for over 40 years. More recently, also affecting fossil LP rotors SCC problem has been greatest for shrunk-on disc rotors, although monobloc rotors are also affected. Excellent SCC track record of Alstom welded rotors.

16 SCC Testing - Extensive Research 40 years of ALSTOM research into the factors affecting initiation and growth of SCC ALSTOM UK (ex-gec) started a comprehensive SCC investigation program into crack initiation and crack growth in pure steam environment over forty years ago More than 500 long term crack initiation tests, some over 100,000 hours duration, in wet steam on NiCrMoV and CrNiMo rotor materials with: a wide range of yield strengths ( ksi) a wide range of applied stresses (between 20% and 100% of the yield strength)

17 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

18 Rotor Dynamics Low vibration levels without in-situ balancing Alstom LP retrofits installed on 15 nuclear units in USA - None required balancing

19 Torsional Testing Experience Modification during Design stage Maanshan Following torsional failure of GE LP, Alstom LP retrofit included a mass wheel to reduce frequency of 2nd generator mode. Callaway Existing unit had 2nd generator mode close to 120 hz. Mass wheel added to reduce this frequency. Quad Cities and Dresden Existing units had 2nd generator mode close to 120 hz. LP/Gen coupling re-designed to reduce mass and increase frequency. Recent Alstom nuclear retrofits in USA have had torsional tests carried out by Customer. Eg: North Anna 2, Surry 1, Quad Cities 2, Peach Bottom 3, DC Cook 1 All had no measured frequencies within ±5% of 120 Hz Measured frequencies close to Alstom calculated values. No corrective actions required.

20 Torsional Frequencies - Summaryional Analysis Good correlation between Alstom calculated and measured values Torsional frequencies of welded drum type LP rotors are above 200 Hz Extensive experience with LP Retrofits on units where Alstom is not the OEM.

21 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

Data Collection/Survey Laser Scanner Use of Laser

uses Leica laser scanner to obtain geometry of

22 Data Collection/Survey Laser Scanner Use of Laser Scanning Technology Well suited to LP retrofits Alstom uses Leica laser scanner to obtain geometry of pipework, supports, foundation and surrounding equipment. From the scan data a CAD model can be generated. LP Frame, Stiffeners and Condenser Geometry Extraction Pipework Geometry

23 Data Collection/Survey Laser Scanner Each scan is line of sight Data collected from a series of scans to build up complete geometry.

24 Data Collection/Survey Laser Scanner Modeled Pipework

25 Agenda 1st topic Introduction Page 1 2nd topic Steam Path Technology and L-0 Selection Page 1 3rd topic Rotor Technology and SCC Page 1 4th topic Rotor Dynamics & Torsional Analysis Page 1 5th topic Data Collection/ Survey Page 1 6th topic Alstom Solutions and Experience Page 1

26 HP Retrofit Experience : Callaway N2R HP and LP Retrofit HP rotor and diaphragms replaced LP Retrofit GE 38 L-0 replaced with Alstom 48R L-0 (47 ) New inner casing & blade carriers

27 HP Retrofit Experience : FT. Calhoun M6 HP and LP Retrofits HP rotor and diaphragms replaced LP Retrofit GE 38 L-0 replaced with Alstom 48R L-0 (47 ) New inner casing & blade carriers

welded rotors (with GE steam path) LP Retrofit : Welded

28 Experience : Quad Cities & Dresden N1 LP Retrofit GE 38 L replaced GE shrunk-on disc rotors with ABB welded rotors (with GE steam path) LP Retrofit : Welded rotors with 48S L-0 (47 ) Inner Casings and Blade carriers

29 Experience : Peach Bottom 1 & 2 N1 LP Retrofit OEM GE 43 L-0 LP Retrofit : Welded rotors with 56R L-0 (57 ) Inner Casings and Blade carriers

with 18 m² L-0 (~56 ) 2008 L-0 blade failure 2011 LP

30 Experience : DC Cook 1 N2R Alstom 2011 LP Retrofit OEM GE 43 L Siemens LP Retrofit : Shrunk on disc rotors with 18 m² L-0 (~56 ) 2008 L-0 blade failure 2011 LP Retrofit : Welded rotors with 56R L-0 (57 ) Siemens inner Casings re-used

31 Experience Diablo Canyon 1 & 2 OEM Westinghouse 3 x BB81LPs with 43 L-0 LP Retrofit : Welded rotors with 56R L-0 (57 ) Inner Casings and Blade carriers New LP rotors fully interchangeable between positions

32 Experience : North Anna & Surry BB281 & 81 LP Retrofit OEM Westinghouse N Anna 3 x BB281LPs with 43 L-0 Surry 3 x BB81 LPs with 43 L-0 LP Retrofit : Welded rotors with 57 L-0 Inner Casings and Blade carriers New LP rotors fully interchangeable between positions and between N Anna and Surry

Experience : North Anna & Surry BB296 & 96 HP Retrofit OEM Westinghouse N Anna BB296 Surry BB96 Existing HP outer casings required extensive repair of erosion

33 Experience : North Anna & Surry BB296 & 96 HP Retrofit OEM Westinghouse N Anna BB296 Surry BB96 Existing HP outer casings required extensive repair of erosion in exhaust area HP Retrofit : Single flow HP module 1.25 Cr outer casing More efficient single flow expansion Steam path thrust balanced by balance piston diameter

34 Experience : Yongwang BB296 HP Retrofit OEM Westinghouse BB296 HP HP Retrofit : Rotor and diaphragms Columbia Oconee -Generating May 2014 Station July 10, 2012

35 Alstom Nuclear Retrofit References No of Unit Fuel Rating Speed Retrofi t Order Retrofit Plant s Type Country (MW) (RPM) Turbine OEM Year Scope Retrofit Details Ulchin 1 & 2 2 Nuclear S. Korea Alstom 2011 HP HP Retrofit Maanshan 1 & 2 2 Nuclear Taiwan GE 2010 HP HP Retrofit Koeberg 1 1 Nuclear S Africa Alstom 2009 LP LP Retrofit Koeberg 2 1 Nuclear S Africa Alstom 2009 LP LP Retrofit Fort Calhoun 1 1 Nuclear USA GE 2009 HP HP Retrofit Peach Bottom 2 1 Nuclear USA GE 2009 LP LP Inner block Peach Bottom 3 1 Nuclear USA GE 2009 LP LP Inner block DC Cook 1 1 Nuclear USA GE 2009 LP LP Inner block Ulchin 1 & 2 2 Nuclear S. Korea Alstom 2008 LP LP Retrofit San Onofre 2 & 32 Nuclear USA English Electric 2008 HP HP rotor, diaphragms + installation Quad Cities 1 1 Nuclear USA GE 2008 LP LP Inner block Dresden Nuclear USA GE 2008 LP LP Inner block N Anna & Surry 4 Nuclear USA Westinghouse 2007 HP, LP HP + 2xLP inner modules per unit Nuclear Retrofit Solutions - KHNP - November 2012

36 Experience : Installation Success Recent achievements: 18.5 days to 25 days for 3 LP inner casings and rotors on six BWR units 24 to 30 days for 2 LP inner casings and rotors with change to single flow HP turbine (extensive pipework modifications) on four PWR units Met contractual commitments Exceptional track record of meeting schedule World s Leading Nuclear Retrofit Supplier

Welded rotor technology avoids SCC Proven LSB design LP Optimal Performance High level of

37 Conclusion Low Risk Retrofit Supplier Most experienced worldwide nuclear retrofit supplier across all designs Consistent and successful operation HP Reliable Operation for Life of Unit Welded rotor technology avoids SCC Proven LSB design LP Optimal Performance High level of efficiency through design Successfully demonstrated performance World s Leading Nuclear Retrofit Supplier

STEAM TURBINE MODERNIZATION SOLUTIONS PROVIDE A WIDE SPECTRUM OF OPTIONS TO IMPROVE PERFORMANCE

STEAM TURBINE MODERNIZATION SOLUTIONS PROVIDE A WIDE SPECTRUM OF OPTIONS TO IMPROVE PERFORMANCE Michael W. Smiarowski, Rainer Leo, Christof Scholten, Siemens Power Generation (PG), Germany John Blake,