KCE-1 Critical Heat Flux CorrelationKCE-1 Critical Heat Flux Correlation for PLUS7 Thermal Design...

APR1400-F-C-EC-13010-NP

KCE-1 Critical Heat Flux Correlationfor PLUS7 Thermal Design (APR1400-F-C-TR-12002)

Introduction

Test Facility and Test Section

Test Procedure and CHF Measurements

CHF Correlation Development

Correlation DNBR Limit

Correlation Application

Conclusion

Key Issues

Non-Proprietary

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Introduction

• PLUS7 Developed for APR1400 & OPR1000*- April 1999 ~ March 2002

• CHF Test for PLUS7 (~ July 2001)- To check the improvement of thermal performance (w.r.t. Guardian)- To get the data for CHF correlation development (KCE-1)- HTRF (Columbia Univ., Closed @ 2003)

• KCE-1 CHF Correlation- Developed based on Same Functional Formula with CE-1- Approval to Design Application by Korean Regulatory Commission

(KINS) on October 2004- Applied to the first reload core(PLUS7) in UCN 4 (OPR1000),

June 2006- Applied to APR1400 PSAR/FSAR

* OPR1000 : Optimized Power Reactor with 1000MWe

• 3 Key Issues from NRC Staffs- NRC Letter, “Acceptance for the Review of Topical Report APR1400-F-

C-TR-12002 (PROJ0782),” Letter from S. Lee (Chief, LB2/DNRL/ONR) to MK Kim (PM, KHNP), June 27, 2013

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Test Facility and Test Section (1/5)

• Heat Transfer Research Facility (HTRF)- Columbia University, New York, NY- Qualified Testing Services for PWR, BWR and PHWR Fuels

since 1970s- Closed on 2003

• HTRF Capacity - Power : ~ 10 MW - Inlet Temperature : ~ 650 deg. F- Exit Pressure : ~ 2,500 psia- Inlet Mass Velocity : ~ 3.7 Mlbm/hr-ft2

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• Schematics of HTRF

EOHL

BOHLCirculation Pump

Heat Exchangers

MixingTee

Pressurizer

TestSection

6x6Rod Bundle

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• Test Section Configuration Unit : inch

Test Section Array

Heater Rod Grid Spacing Guide Tube

Simulator ODAxial Power DistributionOD Pitch Length*

101 6x6 0.374 0.506 150.0 15.72

0.980 1.475 Cosine

102 N/A

* active heated length (electrically heated)

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• Radial Configuration & Spacer Grids

Test Section 101w/ GT Simulator

Test Section 102w/o GT Simulator

Key Issue-1

TS

TS

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• Axial Configuration & Power Distribution

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2

Axial Power Factor (Fz)

Rela

tive

Axi

al E

leva

tio

n (

z/L)

Key Issue-1

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Test Procedure and CHF Measurements (1/5)

• Flow Chart

Start

Isothermal

Pressure Drop

Heat

Balance

CHF Data

Heat

Balance

Isothermal

Pressure Drop

End

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• CHF Measurement- Power Escalation (MW)- Maintaining Other Loop Parameters as Stable as Possible - Rate of Power Increase : Infinitesimal- Records

System Pressure (Pexit) Inlet Mass Velocity (Gin) Inlet Temperature (Tin) Bundle Power (MW) CHF Locations (Heater Rods & T/Cs) etc.

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• Typical CHF Traces

400

500

600

700

800

900

50 60 70 80 90 100

Scan

Tem

pera

ture

( oF)

0

2

4

6

8

10

TS P

ow

er (M

W)

/ G

in (

Mlb

m/h

r-ft 2)

TC a

TC b

TC c

Tin

MW

Gin

CHF

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• Total CHF Data for PLUS7TM

- from Test Section 101 (with GT Simulator)- from Test Section 102 (without GT Simulator)

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1000 1500 2000 2500 3000

Pressure [psia]

Bun

dle

Ave

rage

Hea

t Flu

x [M

Btu

/hr-f

t 2 ]

TS101TS102

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 1 2 3 4

Inlet Mass Velocity [Mlbm/hr-ft2]

Bun

dle

Ave

rage

Hea

t Flu

x [B

tu/h

r-ft 2

]

TS101TS102

TS

TS

TS

Key Issue-2

Bundle Average Heat Flux vs. Pexit, Gin

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• Summary of Test Progress– CHF Test Requirements : February 2001– Test Prospectus : April 2001– QA Audit : April 2001– Testing : May 2001 ~ July 2001– Reporting : August 2001 ~ May 2002

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CHF Correlation Development (1/16)

• Development Procedure- Calculation of Local Coolant Conditions at by

Subchannel Code - Selection of Functional Formula of CHF Correlation- Prediction of CHF by CHF Correlation with the Local Coolant

Conditions at - Optimization of CHF Correlation Coefficients to Minimize the

Deviation between Predicted and Measured CHF at MDNBR Location

- Verification & Validation- Establishment of 95/95 DNBR Limit (Correlation Limit)

TS

TS

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• Design Method/Assumption- Subchannel Code : TORC (CENPD-161-P-A, 1986)- Design Constitutive Relations

• Functional Formula- CE-1 CHF Correlation (CENPD-162-P-A, 1976)

• Specific Consideration- .- .

.

- Resulting in some Conservatism

TS

TS

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• Subchannel Code TORC- Developed based on COBRA IIIC- Modification on Lateral momentum equation and Lateral

boundary condition capability- Multi/Open Channel (steady-state)- Divide Core into a series of Control Volume and Solve 3

dimensional conservation equations for each Control Volume - Verification including a comparison of CHF test bundle and

actual operating reactor data- Approved for Application to Reactor Thermal Analysis

(CENPD-161-P-A, 1986 & CENPD-206-P-A, 1981)

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• Design Constitutive Relations (TORC)

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• Thermal Mixing Factor- Inverse Peclet Number, 1/Pe = W’ / (G•De)

- for CHF Data Analysis

- Based on Geometric Similarity R-type Split Mixing Vane

Grid Spacing ≤ 26 inch

TS

TDC : Thermal Diffusion Coefficient (1/Pe • De/a)a = rod-to-rod gap

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• Specific Consideration-1 : .

- . -

.

- . TS

TS

TS

TS

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• Specific Consideration-2 : Application of FTong

– Development Stage (CHF Data)• DNBR = q″CHF, Pred / q″CHF, Meas

• q″CHF, Meas =

• q″CHF, Pred (development) = q″CHF, KCE-1 ~

– Application Stage (Reactor Thermal Design)• DNBR = q″CHF, Pred / q″local, Actual

• FTong = : Correct the effects of

Non-Uniform Axial Power Distribution (NU APD) on CHF

• q″CHF, Pred (application) = q″CHF, KCE-1 / FTong ≤

– Note that q″CHF, NU ≤ q″CHF, U

TS

TS

TS

TS

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• FTong : Correction Factor for the effects of NU APD on CHF

- FTong = q″CHF, U / q″CHF, NU

- Relevant References : Applicability & ExperiencesRosal, E.R., et. al., Nuclear Engineering and Design 31 (1974)

WCAP-8762-P-A (1978), WCAP-10444-P-A (1985)

CENPD-207-P-A (1984)

whered1 = 1.50E-01d2 = 4.31E+00 d3 = 4.78E-01

l

ZSl

Tong dzzlCzqlCq

CF expexp0.1

]/1[

101

3

2

61 inchG

XdC dloc

dloc

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• Correlation Detail

))(G/10BP(B6

fg6P)B(B6

43

B

11KCECHF, 6

87

652

)(G/10

hχ)(G/10)(G/10P)B(B(DH/DHM)Bq

Parameter Range CE-1 KCE-1

Pressure, psia 1785 ~ 2415 1395 ~ 2415 Mass Velocity, Mlbm/hr-ft2 0.87 ~ 3.21 0.85 ~ 3.15

Local Quality -0.16 ~ 0.20 -0.15 ~ 0.28

)/( PMx )/( PMsTest Section n

101102ALL

TS

TS

Key Issue-2

Coefficient CE-1 KCE-1B1B2B3B4B5B6B7B8

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• M/P Parametric Trends w.r.t. Pressure (5.3 Validation & Verification)

95/95 Limit

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• M/P Parametric Trends w.r.t. Local Mass Velocity (5.3 Validation & Verification)

95/95 Limit

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• M/P Parametric Trends w.r.t. Local Quality (5.3 Validation & Verification)

95/95 Limit


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• M/P Parametric Trends w.r.t. Heated Diameter Ratio (5.3 Validation & Verification)

95/95 Limit


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• Measured CHF vs. Predicted CHF Trends (5.3 Validation & Verification)

95/95 Limit


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• Validity of Specific Consideration-1 (5.3 Validation & Verification)

– Confirmed by Comparison of the 95/95 DNBR Limits w/ Specific Considerarion-1 : 1.124 (see page 31) w/o Specific Considerarion-1 : (see Table below)

– Conservative & Valid

– Statistics of KCE-1 CHF Correlation w/o Specific Cosideration-1

TS

TS


Test Section n 95x95 DNBR Limit

101102ALL

)/( PMx )/( PMs

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• Validity of Specific Consideration-2 (5.3 Validation & Verification)

– Comparison of M/P for CHF Data : w/ FTong vs. as Developed

Key Issue-3


TS

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Correlation DNBR Limit (1/4)

• Statistical Analysis– Distribution Characteristics

• D’-test/ W-test (ANSI N15.15-1974)• Parametric or Non-Parametric

– Poolability• Parametric : F (Bartlett) test / T test• Non-Parametric : Wilcoxon-Mann-Whitney test

– Outlier

• 95/95 Limit– Parametric : Inverse of M/P Lower Bound with Owen’s 1-side

Tolerance Factor (SCR-607, 1963)– Non-Parametric : Inverse of M/P at m-th rank (Experimental

Statistics, Handbook 91, National Bureau of Standards, 1966)

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• Distribution Characteristics – D’-test

• Pass : Test Section 102, ALL (Combined)• Fail : Test Section 101

– Parametric and/or Non-Parametric

• Poolability (Test Sections 101 & 102)– Parametric

• F (Bartlett) Test : Pass• T Test : Fail

– Non-Parametric • Wilcoxon-Mann-Whitney Test : Fail

• Outlier– .

TS

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• M/P Frequency Distribution (Test Section 101)

0

5

10

15

20

25

30

35

40

45

0.82 0.88 0.94 1 1.06 1.12 1.18 1.24

Ratio of Measured to KCE-1 Predicted CHF

Num

ber o

f Dat

a

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• 95/95 DNBR Limit– Parametric

– Non-Parametric

TS

TS

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Correlation Application

• DNB Acceptance Criteria- SRP Sections 4.2 & 4.4- 95/95 DNBR Limit : 1.124 (Chapter 5 of APR1400-F-C-TR-12002-P)

• Design Computer Codes- TORC : Full Compliance with the Approved Conditions,

CENPD-161-P-A & CENPD-206-P-A- CETOP : Full Compliance with the Approved Conditions,

CEN-139(A)-P & CEN-214(A)-NP- Implementation KCE-1 CHF Correlation to Computer Code :

Modifying only the Coefficients of CE-1 CHF Correlation

• Design Application- DNBR = [q”CHF, KCE-1U/FTong] / q”actual

- FTong : - 1/Pe = 0.0101 (TDC = 0.038) < Value Applied to Development- DNBR(CETOP) ≤ DNBR(TORC) for all Reactor Conditions

TS

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Conclusion

• CHF Test - HTRF- 6x6 Rod Bundle (Best Representative of PLUS7)- NU APD (~1.5 Cosine)

• KCE-1 CHF Correlation- Same Functional Formula with CE-1 Correlation- Design Subchannel Code/Constitutive Relations- 95/95 Limit : 1.124- Specific Considerations resulting in Conservatism

• Applied to APR1400 & OPR1000 Design Analysis for PLUS7

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AcronymsAPD : Axial Power DistributionCHF or q″CHF : Critical Heat FluxDH, DHM : Heated Diameter of Subchannel and DH of Matrix Subchannel,

respectivelyDNBR : Departure from Nucleate Boiling RatioFTong : Tong F Factor, Correction factor for the effects of NU APD on CHFG or Gloc : Local Mass Velocity (Mass Flux)Gin : Inlet Mass Velocity (Mass Flux)GT : Guide Tubehfg : Latent HeatK95x95 : Owen’s 1-side tolerance factor (per 95% probability with 95% confidence) M/P : Ratio of Measured to Predicted CHFn : Number of DataNU, U : Non-Uniform and Uniform, respectivelyOD : Outside Diameter P or Pexit : System PressurePe : Peclet Numberq″CHF, KCE-1 : Predicted Critical Heat Flux by KCE-1 CHF Correlationq″l or q″local, Actual : Actual Local Heat Fluxq″CHF, Meas : Measured Critical Heat Fluxq″CHF, Pred : Predicted Critical Heat FluxSTD : Standard Deviation T/C : ThermocoupleTDC : Thermal Diffusion CoefficientTin : Inlet TemperatureTS : Test Section (* Superscript on Bracket : Trade Secret)x or Xloc : Local Qualityz : Axial Elevation zs : Starting Axial Elevation for integration (per definition of FTong)

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Key Issues [NRC Letter : Acceptance for the Review of TR , June 27, 2013]

Testing Bundle - The staff needs more information regarding the testing bundle and how well it represents the fuel bundle to be used for APR1400. While this is a TR which mostly provides methodology, the methodology needs to be shown to be applicable to the APR1400 fuel.

Testing Parameter Range – The testing parameter range in the TR appears to be insufficient to cover the intended analysis range of pressure. The NRC staff expects that KHNP will provide the range of relevant parameters from the accident analysis, including system pressure, local mass flux and local quality.

Axial Profile Shape - The TR describes a cosine profile shape used in the testing, the staff needs more information regarding the axial profile used in the testing program and how well it represents the profile experienced during the operation of the APR1400. Specifically, the staff wants more details on the applicability of the testing axial profile to the full cycle.

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CHF Test Section vs. PLUS7 Fuel Assembly (1/3)

• Test Section Configuration Unit : inch

Test Section Array

Heater Rod Grid Spacing

GT Simulator OD

Axial Power Distribution Note

OD Pitch Length

101 6x6 0.374 0.506 150.0* 15.72

0.980 1.475 Cosine Heated by

Electricity102 N/A

PLUS7TM 16x16 Same Same Same Same 0.980 - Heated by Fission

* BOHL ~ EOHL

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• Axial Configuration (Not to Scale)

EOHL

BOHL

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• Spacer Grids with Mixing Vane (R-type Split)

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Application Range

Parameter Range CHF Data APR1400 Operation

CHF CorrelationCE-1 KCE-1

Pressure, psia 1395 ~ 2495 1785 ~ 2415 1785 ~ 2415 1395 ~ 2415

Inlet Mass Velocity, Mlbm/hr-ft2(Local Mass Velocity) 0.9 ~ 3.7 2.0 ~ 3.2* 0.87 ~ 3.21 0.85 ~ 3.15

Inlet Temperature, ℉(Local Quality, fraction) 250 ~ 640 500 ~ 595 -0.16 ~ 0.20 -0.15 ~ 0.28

* Core average value ( ~ 1.6 @ Locked Rotor Statepoints)

• KCE-1 CHF Correlation Application- AOOs- DNB Limiting Transients

Loss of Flow, Locked Rotor Steamline Break @ HFP, etc.

• Alternative CHF Correlation- Outside of KCE-1 CHF Correlation Applicable Range- MacBeth CHF Correlation

Approval : LD-WO-3900, August 1983 Letter from NRC (C. B. Brinkman) to CE (A. E. Scherer)

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CHF Data/Design Application (1/6)

• CHF Data (~ 1.5 Cosine)

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2

Axial Power Factor (Fz)

Rela

tive

Axi

al E

leva

tio

n (

z/L)

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• Specific Consideration-2 : Application of FTong

– The Effect of NU APD on CHF (Page 18) Implemented inherently in Test Data with NU APD Correlation Developed with Test Data with NU APD Implementing additionally in Design Analysis

– References Initially Proposed : Tong, L.S., et. al. (1965) with 5 NU APD

“Influence of Axially Non-Uniform Heat Flux on DNB,” AIChE Preprint 17, 8th National Heat Transfer Conference, LA California, 1965.

Proposal to Reactor Thermal Design : Tong, L.S. (1967) with 3 NU APD“Prediction of Departure from Nucleate Boiling for an Axially Non-Uniform Heat Flux Distribution,” Journal of Nuclear Energy 21, 1967.

for Rod Bundle : Rosal, E.R., et. al. (1974) with 2x2 NU APD“High Pressure Rod Bundle Data with Axially Non-Uniform Heat Flux,” Nuclear Engineering and Design 31, 1974.

Experiences of Design Application (Page 19)

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– Application Experiences

WRB-1 CHF Correlation (WCAP-8762-P-A, 1978) Developed with U APD Data Applying FTong to NU APD Data Acceptable Correlation Database : U APD & NU APD Data Design Application with FTong Acceptable

TS

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– KCE-1 CHF Correlation

No U APD Data Developed with NU APD Data (q″CHF, NU ≤ q″CHF, U) Correlation Database : NU APD Data Design Application with FTong Conservatism

TS

95/95 Limit

TS

TSTS

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– Assessment with Other Applicable CHF Correlation

EPRI-1 (EPRI NP-2609, 1982) : Wide Applicable RangeFg : Effect of Spacer Grid on CHFCnu : Effect of NU APD on CHF

WRB-2 (WCAP-10444-P-A, 1985)FTong : Effect of NU APD on CHF

Parameter WRB-2 DB PLUS7 Remark

Mixing Vane RTSV same type

Grid Spacing, in. 10 ~ 26 15.72 within range

Heated Length, in. ~ 168 150 “

Fuel Rod Pitch, in. 0.485 ~ 0.523 0.506 “

Fuel Rod OD, in. 0.360 ~ 0.406 0.374 “

Guide Tube OD, in. 0.471 ~ 1.024 0.980 “

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– Assessment with Other Applicable CHF Correlation

EPRI-I / WRB-2

0

0.5

1

1.5

2

TS101 TS102

M/P

PLUS7 CHF Data

KCE-1 wo FTong KCE-1 w/ FTong EPRI-1 w/ Fg & Cnu WRB-2 w/ FTong

KCE-1 Critical Heat Flux CorrelationKCE-1 Critical Heat Flux Correlation for PLUS7 Thermal Design...

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