secondary circuit mapping of fac and high velocity -two ...€¦ · 19,00 19,30 bar kg/h ºc 62,1...

11IAEA WK on ECIAEA WK on EC-- April 2009April 2009

M. Chocrón1, I. Rodriguez1, M. Contino1, R.Saucedo2 andJ.Duca

(1)Comisión Nacional de Energía Atómica (CNEA)-Argentina(2) Central Nuclear Embalse-Nucleoeléctrica Argentina S.A. (NASA)

(3) UG-Atucha II - Nucleoeléctrica Argentina S.A. (NASA)

IAEA Workshop on Erosion-Corrosion (E/C) Including Flow Accelerated Corrosion (FAC) and Environmentally

Assisted Cracking (EAC) Issues in Nuclear Power Plants. 21-23 April 2009, Moscow, Russian Federation.

SecondarySecondary CircuitCircuit MappingMapping ofof FAC FAC andandHighHigh VelocityVelocity --TwoTwo PhasePhase FlowFlowMechanicalMechanical DegradationDegradation EffectsEffects


Contents

•Overview•Objectives: BOP integrated assessment program•Evaluation of FAC•Mechanical degradation effects:Jet impingementCavitation-flashingDropplet erosion•Water Chemistry improvements•Atucha II: BOP and Water Chemistry•Acknowledgements


Overview: Operating N.P.Ps.

Atucha I – PVHWR – SIEMENS KWU - 1974Embalse CANDU®600 PHWR- AECL-Cordoba-1984Atucha II – PVHWR – SIEMENS KWU – Buenos Aires – In Construction


� Since the start-up (1984) Embalse has been carrying out a program of Piping Thickness Inspection guided by measurement results

� Since 2004, with the start up of the PLiM/LTO Project, an integrated program for FAC evaluation began to be developed in order to determine the wall thinning rate of the Secondary Circuit piping and components

� The Program has been developed by Embalse NPP engineering staff along with the Comision Nacional de Energia Atómica (National Atomic Energy Commision). It is documented in several international workshops and conferences.

Objectives


Objectives


• Understanding the Flow Assisted Corrosion Degradation Mechanism and its related variables (hydrodynamics, chemistry, etc.), already acquainted after PHTS components.

• Development of a Calculation Code to predict thinning rate in relevant steam/water cycle points based on FAC theory and assisted by CFDtools.

• Creation of a detailed Data Base for piping and accessories (dimensions, materials, process data, chemistry conditions, inspection data, etc.)

• Identification and Screening of components to be inspected, repaired or replaced (ISI optimization).

( )' 1 1( )w

d m e

S Cm

k k k

−=

+

Evaluation of FAC


• Examples of Data Bases

Evaluation of FAC

Extracción de turbina BP A (VEX TBP) al precalentador E-102A - DN 600 43119 0165 43119-5004-01-DD

VEX TBP A a E-102A - DN 600 43119 0165 43119-5004-01-DD

IDENTIFICACION

Descripción Código BSI Número de línea Plano Isométrico

σ ( N /m 2 ) D e 1 ( m ) S ( m 2 ) S c h% C r % M o

A 1 0 6 B 0 ,0 3 0 ,0 3 1 ,0 3 1 E + 0 8 0 ,6 0 9 6 0 ,2 7 3 9 2 0

A 2 3 4 W P B 0 ,0 3 0 ,0 3 1 ,0 3 1 E + 0 8 0 ,6 0 9 6 0 ,2 7 3 9 2 0

M A T E R IA L Y D A T O S G E O M E T R IC O SD e 2 ( m ) ( S ó lo p a r a

r e d u c c io n e s )M a t e r ia l C o m p o s ic ió n

e 1 (m ) e c a lc (m ) e t f ( m ) D i 1 ( m ) L (m ) S t ( m 2 )

0 ,0 0 9 5 0 ,0 0 7 0 ,0 0 8 0 ,5 9 0 5 6 0 ,4 6 0 ,8 5 3

0 ,0 0 9 5 0 ,0 0 7 0 ,0 0 8 0 ,5 9 0 5 6 2 ,6 6 4

M A T E R IA L Y D A T O S G E O M E T R IC O Se 2 (m )

(S ó lo p a ra r e d u c c io n e s )

D i 2 (m ) ( S ó lo p a ra

r e d u c c io n e s )

Dens idads V iscos idads T ítu lo DFe(OH )2 Sw CoK g /m 3 K g /m seg x s m 2/se g (pp b) (p pb )

1 ,0 8 1 ,2 9E -05 0 ,95 59 8 ,52 E -0 9 2 0 ,2 00 1

1 ,0 8 1 ,2 9E -05 0 ,95 59 8 ,52 E -0 9 2 0 ,2 00 1

D A T O S T E R M O D IN A M IC O S Y P R O P IE D A D E S


Data: Data: TemperatureTemperature, , PressurePressure andand FlowFlow RateRate

3.26699,712,50

3.26619012,50

2.548.872330,05

19013

3.105.251

249.305

2.827.057

19012,4

233

278.194

190

190

190

026046,9

46,9260

136.75970,43

19,00 19,30

bar

kg/hºC

62,1

257

12,5

2603.113.411

260

8.582

QTP

257

249.305

58.790

249.305260

45,50

46,8746,9260726

3.365.837260

2.699

46,9

46,873.116.532

42226046,87

3.373.300

278.194

12,40

8.160

118,67,36

11221,10

158,4416,78 6,77

3720,40

6,77 1,75701.327117,64 115,69

824.428

0,27

69

0,731,75 0,27

0,73337.50342,33

66,0085,00

162,83 116,50 90,46

1,900,52

2.548.8722.548.872

33

41.729 159.01582

66,540,30

12,04

2.136.534

157,44

26046,9 12,50

190

123.101

12,40

195

6.737330,06

3.373.300

1,21

6.737

171.129

105

647.000

20.30345,50

0,16

0,05

5.316

56

0,7993

116.456

46,87260

3.366.563

46,87 3

G

SSR1-2-3

1

2

CS


Data: Data: TemperatureTemperature andand vapor vapor fractionfraction

0,9975

0,9975

0,00

260

2600,9975(0105)

260 190

37,21

190(0312)

0,00

0,00

(0318)

194,6

(0176)

0,731,75

(0532A)116,50

(0165)

1050,5867(36319-W1)

118,6(0162)0,9980

0,9975(0105)

260

647.000

56

(0532)

33

93,20,8093256,9

0,00 (0168)

(0553)0,00

0,00

70,43

(0342)115,69

0,9559

90,46

85,00

0,2081

(0541)117,64

(0547)0,00

0,00

(0371)

158,440,00

1126,77

0,9975

162,83

(0193)

162,83(0519A)

0,00(0519)

260(0106)

(0204)

189,5 189,5

0,9975

190(0511)0,00

190

(0114)

0,00(0505)

260

260

0,9975(0126)

260 T

233(0120)

X

1,000

ºC

257

260

260

(0110)

190(0174)

0,673082,150,2651

68,86

(0349)99,66

0,270,00

TítuloN° de l ínea

330,00

33

0,9975(0105)

(0559)

(0326)

42,330,00

(0169)

66,00 37,21

66,54

(0415)

0,00(0353)

157,440,00(0380)

162,83

0,00115,69

0,0578

3

G

SSR1-2-3

1

2

CS


As a result of the Integral BOP Life Assessment System, a wall As a result of the Integral BOP Life Assessment System, a wall thinning rate categorizationthinning rate categorization is divided into five areas as shown is divided into five areas as shown in the following flow sheet:in the following flow sheet:

��Green lines (very low thinning rate)Green lines (very low thinning rate)��Blue lines (low thinning rate)Blue lines (low thinning rate)��Yellow lines (moderate thinning rate)Yellow lines (moderate thinning rate)��Orange lines (relevant thinning rate)Orange lines (relevant thinning rate)��Red lines (high thinning rate)Red lines (high thinning rate)

This considers not only the predicted wall thinning rate but alsThis considers not only the predicted wall thinning rate but also o the different manufacture thickness in their respective locationthe different manufacture thickness in their respective location

Evaluation of FAC


(0415)

136,61(0353)

157,44157,91(0380)

162,83

64,44115,69 7,14

( 0559)

8,50(0326)

42,33

(0505)260

260216,39(0105)

219,69(0105)

7,40

µm /añoN° de línea

334,26

33

(0318)8,50

(0349)99,66

0,2766,00 37,2161,10

66,54

(0193)

190(0174)

472,37

189,5 189,5

90,46

ºC

257

260

260

(0110)

260 T

233(0120)

m'

179

(0204)13,44

260

260

1,78(0126)

626,88

202,47

190(0511)12,23

190

(0114)

260(0106)211,34

162,83 116,50

(0165)700,84

3,60

28,33(0519)

85,00

115,69

(0532A)

(0371)

158,44143,24

112

(0519A )

(0547)86,67

6,77 73,22 0,73

81,22(0553)7,5070,43

(0342)

(0541)117,64

1,75

(36319-W1)

616,10162,83

118,6(0162)

647.000

56

(0532)

33

93,2690,78256,9

15,47 (0168)

190105215,15

219,70(0105)

82,1565,57

260

194,6

2604,10

(0169)

124,42 231,58

190

37,21

68,86(0176)

(0312)

3

G

SSR1-2-3

1

2

CS

Evaluation of FAC: Relative WTR due to FAC


Mechanical degradation effects

�Under FAC conditions, mass transfer dominates while over a criticalvelocity-Two phase flow, the protective oxide is mechanicallyremoved and even the base metal attacked.�There are no theories at the macro level capable of predictingdegradation as in the case of FAC.

�It has been part of the BOP assessment program to develop a map for1- Jet impingement2- Cavitation-flashing3- Dropplet erosion


Jet impingement

•Heat and mass transfer in turbulet jets extensively studied.•Four zones can be distinguished: A-Laminar stagnation, B-Highturbulence, C-Low turbulence and D-Turbulent Boundary layer as distance from jet increases.

•It can be related to FAC by shear stress analogy.•However, CFD modeling helps with the location, extension andinterpretation of damage.•Typical of Tees and Turbine extraction lines at preheater entranceshells.

2 0.182 2.00

0

0.179 Re ( )w

rUr

ρ − −Γ =


Jet impingement

1 9

2

3

4

5 6

78

10

E-101 APreheater showing LPT extraction lines

CFD modeling atpreheater entrance


Cavitation-flashing

•In cavitation, after a depression where the fluid approachessaturation, pressure is recovered and the bubbles implote creating a microjet that damages the surface•In flashing, bubbles tend to remain eroding the surface•While principles are well fundamented at microscale, a SC map can only be based on the, rather obvious, cavitation number as a potentialof approaching bubble pressure.

2

( )12

vP PKVρ

∞ −=

K>>1 Subcooled liquid with low linear velocity and absolute pressure higher enough than saturation pressure at temperature.

K<0 Supersaturated steam.

K=0 Local steam quality must be analized. If saturated liquid, the creation of bubbles is feasible. With high steam quality, there is no posibility of cavitation.

K≈0 High posibility of cavitation-flashing is expected at those locations.


0,9975

0,9975

0,00

260

2600,9975(0105)

260 190

37,21

190(0312)

0,00

0,00

(0318)

194,6

(0176)

0,731,75

(0532A)116,50

(0165)

1050,5867(36319-W1)

118,6(0162)0,9980

0,9975(0105)

260

647.000

56

(0532)

33

93,20,8093256,9

0,00 (0168)

(0553)0,00

0,00

70,43

(0342)115,69

0,9559

90,46

85,00

0,2081

(0541)117,64

(0547)0,00

0,00

(0371)

158,440,00

1126,77

0,9975

162,83

(0193)

162,83(0519A)

0,00(0519)

260(0106)

(0204)

189,5 189,5

0,9975

190(0511)0,00

190

(0114)

0,00(0505)

260

260

0,9975(0126)

260 T

233(0120)

X

1,000

ºC

257

260

260

(0110)

190(0174)

0,673082,150,2651

68,86

(0349)99,66

0,270,00

Títu loN° de l ínea

330,00

33

0,9975(0105)

(0559)

(0326)

42,330,00

(0169)

66,00 37,21

66,54

(0415)

0,00(0353)

157,440,00(0380)

162,83

0,00115,69

0,0578

3

G

SSR1-2-3

1

2

CS

Cavitation-flashing

Cavitation-flashing expected zones (red symbols)


Dropplet erosion

•Depends on the flow, velocity, temperature, base metal and waterchemistry (pH and ECP).

•In SCs of NPPs, dropplet erosion prone zones are those of straightpipes with annular flow or dropplet dispersed flow close toaccesories (elbows, tees) where liquid phase impacts the walls.

•Therefore, effort has been devoted to better prediction of voidfraction-TPF zones with annular flow by comparison amongseveral correlations considering angles (Tandon, Baker and Taitel-Dukler for horizontal flow and Hewitt-Roberts for vertical flow).


0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.75

0.8

0.85

0.9

0.95

1

Homogeneous ModelModified Smith ModelCrisholm ModelArmand ModelLockhart-Martinelli ModelZivi ModelMartinelli-Nelson ModelThom ModelAverage between models

10-6 10-5 10-4 10-3 10-2 10-1 100 101 10210-3

10-2

10-1

100

101

Stratified Flow

Transition Range

Annular Flow

Spray Flow

Plug Flow

Slug Flow

Bubly Flow

SM ModelMN ModelT ModelZ ModelC Model

Predicted void fraction after severalmodels Predicted flow regime after

Tandon Map for horizontal flow

Dropplet erosion


Table VI Line Tag T

(ºC) P

(bar) x W

(Kg/s) Taitel Tandon SM

Tandon MN

Tandon T

Tandon Z

Tandon C Baker H-R

(Vertical) 120 233 12 1 130.882 162 194.6 7.36 0.998 15.845 * * * * * * * 105 260 46.9 0.998 935.156 * * * * * * * * 105 260 46.9 0.998 934.955 * * * * * * * * 126 260 46.9 0.998 0.202 114 260 46.9 0.998 34.626 * * * * * * * * 105 260 46.9 0.998 865.703 * * * * * * * * 204 260 46.9 0.998 0.117 106 260 46.9 0.998 216.21 * * * * * * * * 193 260 46.9 0.998 0.25 165 118.6 1.9 0.956 11.398 * 110 189.5 12.4 0.91 215.642 * * * * * * * * 168 93.2 0.79 0.809 10.783 * 176 68.86 0.3 0.673 14.724 * 169 105 1.21 0.587 1.88 174 82.15 0.52 0.265 3.864 0532 A 162.8 6.77 0.208 11.542 * * * 0519 A 162.8 6.77 0.058 12.879 * * *

SM: Modified Smith; MN: Martinelli-Nelson; Z: Zivi; C: Crisholm; T: Thom; H-R: Hewitt-Roberts

10-5 10-4 10-3 10-2 10-1 100 101 102 1032 3 45 2 3 45 2 3 45 2 3 45 2 3 45 2 3 45 2 3 45 2 3 45

X

100

101

102

103

104

2346

2346

2346

2346

K

10-3

10-2

10-1

100

101

2

3457

2

3457

2

3457

2

3457

T or

F

FTK

Annular Flow

Wav y Flow

Stratified Flow

Bubbly Flow

Intermittent (plug/slug flow)

Flow Pattern Chart for Horizontal Tubes (Taitel and Dukler)

Dropplet erosion

Predicted flow regime after Taitel-Dukler Map for horizontal flow

Annular flow prediction andcomparison after several models


Cavitation-flashing

Annular flow-Dropplet erosion according to different models (circles)

0,9975

0,9975

0,00

260

2600,9975(0105)

260 190

37,21

190(0312)

0,00

0,00

(0318)

194,6

(0176)

0,731,75

(0532A)116,50

(0165)

1050,5867(36319-W1)

118,6(0162)0,9980

0,9975(0105)

260

647.000

56

(0532)

33

93,20,8093256,9

0,00 (0168)

(0553)0,00

0,00

70,43

(0342)115,69

0,9559

90,46

85,00

0,2081

(0541)117,64

(0547)0,00

0,00

(0371)

158,440,00

1126,77

0,9975

162,83

(0193)

162,83(0519A)

0,00(0519)

260(0106)

(0204)

189,5 189,5

0,9975

190(0511)0,00

190

(0114)

0,00(0505)

260

260

0,9975(0126)

260 T

233(0120)

X

1,000

ºC

257

260

260

(0110)

190(0174)

0,673082,150,2651

68,86

(0349)99,66

0,270,00

TítuloN° de línea

330,00

33

0,9975(0105)

(0559)

(0326)

42,330,00

(0169)

66,00 37,21

66,54

(0415)

0,00(0353)

157,440,00(0380)

162,83

0,00115,69

0,0578

3

G

SSR1-2-3

1

2

CS


Monitoring Results

• Turbine extraction lines (TBP-A) and drainage lines during 2005 Outage. Regions with localized degradation (8 out of 21 measured areas show a localized degradation > 30% ) have been found in the extractions of the TBP-A toward the preheater E-104A. The highest wall thinning has been observed in the areas of the straight pipe toward the preheater, adjacent to 45º elbow.

• Turbine extraction lines TBP-A/C during 2007 outage: regions with localized degradation (13 out of 20 measured areas have shown localized degradation > 30 %) have been found in the extractions of the TBP-A/C toward E-104-A/C preheaters., again close to 45o elbows.


Monitoring Results

•Wall thickness measurements of CS high pressure preheater shells (E-101/102) to obtain information about the equipment status.

•Extension of piping thickness measurements in SGs feedwater lines during 2007 outage: given that in 2006 a break ocurred in other NPP, downstream of a flow element, the plant decided to extend program considering new 45 critical zones. Only 4 (90o elbows) have shown wall thinning > 12.5 % but < 30 % referred to nominal thickness.•Moisture Separator Reheater entrance pipe.


New specifically inspected zones

Monitoring Results

(0415)

136,61(0353)

157,44157,91(0380)

162,83

64,44115,69 7,14

(0559)

8,50(0326)

42,33

(0505)260

260216,39(0105)

219,69(0105)

7,40

µm/añoN° de línea

334,26

33

(0318)8,50

(0349)99,66

0,2766,00 37,2161,10

66,54

(0193)

190(0174)

472,37

189,5 189,5

90,46

ºC

257

260

260

(0110)

260 T

233(0120)

m'

179

(0204)13,44

260

260

1,78(0126)

626,88

202,47

190(0511)12,23

190

(0114)

260(0106)211,34

162,83 116,50

(0165)700,84

3,60

28,33(0519)

85,00

115,69

(0532A)

(0371)

158,44143,24

112

(0519A )

(0547)86,67

6,77 73,22 0,73

81,22(0553)7,5070,43

(0342)

(0541)117,64

1,75

(36319-W1)

616,10162,83

118,6(0162)

647.000

56

(0532)

33

93,2690,78256,9

15,47 (0168)

190105215,15

219,70(0105)

82,1565,57

260

194,6

2604,10

(0169)

124,42 231,58

190

37,21

68,86(0176)

(0312)

3

G

SSR1-2-3

1

2

CS


Water Chemistry Improvements

•pH has been gradually augmented with eventual replacement ofMorpholine by ETA•Highly beneficial impact on reduction of Fe transport along the circuit has been observed

3 02 52 01 51 05

B a s e C o n c e n t ra t i o n (mg / K g )7 8 9 1 0 1 1 1 2 1 3 1 4 1 5

Conductivity (µS/cm)9.4

9.49.59.59.69.69.79.7

9.89.8

9.99.9

1010

pH at

25ºC

pH at

25ºC

1 8/ 0 1

/ 2 00 7

2 8/ 0 4

/ 2 00 7

0 6/ 0 8

/ 2 00 7

1 4/ 1 1

/ 2 00 7

2 2/ 0 2

/ 2 00 8

0 1/ 0 6

/ 2 00 8

0 9/ 0 9

/ 2 00 8

1 8/ 1 2

/ 2 00 8

2 8/ 0 3

/ 2 00 9 Date

2

7

12

17

22

27

Base

Conc

entra

tion (

mg/K

g)0.0

0.5

1.0

1.5

2.0

2.5

3.0

Iron C

once

ntrati

on (µ

g/Kg)

F e in FWBas e Concentrat ion in F W

Fe and Base ConcentrationPeriod 2007-2009


GV

Line 5

Line

2

Line

1

to line 13Line 3

Line 4

Line 6

Line

7

Line

11

Line

8

Line

10

Line

9

Line

12

Line

14

Line 13

Line

16

Line

15

Line

17

Line

18

Line 19

Line 20

Line 24

Line 25

Line 21

Line 26

Line

37

Line

36

Line

35

Line

34

Line

33

Line 29

Line 30

Line 31

Line 32

Line 28Line 23

Line 27Line 22

SteamGenerator

Reactor

Feed WaterTank

Turbine Turbine

Power 744,7/693 Mwe Cycle water Demineralized water Thermal power 986,35 MW x 2 = 1972,7 MW No of tubes in the SGs 6524 x 2 = 13.048 Tube material and dimensions Incolloy 800/18 x 1 mm TSPs DIN 1-4550 U-bend Incolloy 800 TP cladding DIN 1-4550 Inlet and outlet SGs temperature 313,8/277,5 oC Temperature and quality of steam 271,0 oC/54,9 bar/0,9975 Nº of Moderator HXs 4 Thermal power 50,7 x 4 = 202,8 MW No of tubes 1065 x 4 = 4260 Material and dimensions 12 x 1 mm Incolloy 800 TSPs DIN 1-4550 TP cladding DIN 1-4550 Inlet and outlet Moderator HX 194,2/140,0 oC FW train St 37-0 Low pressure preheaters AISI 316 L High pressure preheaters AISI 316 L FW tank temperature 121 oC Condenser tubing AISI 316 L Nº of tubes and dimensions 2 x 35.358 = 70.716 / 21 x 0,7 x 15239

mm Material AISI 316 L Gases extraction box AISI 316 L Chemistry High AVT

Water Chemistry-Atucha II


Steam Generator Blowdown

Control Parameters Normal Operation Values Action Level 1 Action Level 2 Action Level 3

Cation Conductivity [µS/cm]1) < 0.2 > 1.0 > 2.0 > 7.0 Sodium [mg/Kg] < 0.005 > 0.05 > 0.1 > 0.5

1) Caused by only strong anions; organics and CO2 are not to be considered.

Diagnostic Parameters Normal Operating Values pH at 25ºC > 9.6 Chlorides (Cl-) [mg/Kg] < 0.01 Sulphates (SO4=) [mg/Kg] < 0.01 Ammonia [mg/Kg] < 1,5

Complementary Parameters Normal Operating Values

Iron [mg/Kg] < 0.005 SiO2 [mg/Kg] < 0.1

Feed Water

Control Parameters Normal Operation Values Action Level 1 Action Level 2 Action Level 3

pH a 25ºC > 9.8 < 9.8 --- --- Cationic Conductivity [µS/cm]1) < 0.15 > 0.2 --- --- Oxygen [mg/Kg] < 0.005 > 0.005 > 0.02 2) > 0.1 (1) Caused by only strong anions; organics and CO2 are not to be considered. (2) Power reduction is not required.

Diagnostic Parameters Normal Operating Values Hydrazine [mg/Kg] > 0.02 Specific Conductivity [µS/cm] < 15.0 Ammonia [mg/Kg] 10.0 - 12.0

Complementary Parameters Normal Operating Values

Iron [mg/Kg] < 0.001

Water Chemistry-Atucha II

Feed water specifications

Steam Generator specifications


Acknowledgements

• The IAEA is gratefully acknowledged for the support giventhrough the Projects RLA 4021 and 4091


Thank you for your attention!

secondary circuit mapping of fac and high velocity -two ...€¦ · 19,00 19,30 bar kg/h ºc 62,1...

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