the use of the natural circulation flow map

THE THE USE OF THE NATURAL USE OF THE NATURAL CIRCULATION FLOW MAPCIRCULATION FLOW MAP

F. D’Auria, D. Araneo, B. Neykov – Lecture T20

DIPARTIMENTO DI INGEGNERIA MECCANICA, NUCLEARE E DELLA PRODUZIONE

UNIVERSITA' DI PISA56100 PISA -ITALY

IAEA & ICTP Course onIAEA & ICTP Course on

NATURAL CIRCULATION IN WATER-COOLED NATURAL CIRCULATION IN WATER-COOLED NUCLEAR POWER PLANTSNUCLEAR POWER PLANTS

Trieste, Italy, June 25-29 2007 Trieste, Italy, June 25-29 2007

2/61

Local Transport Phenomena & Models

• LOCAL MASS, MOMENTUM AND ENERGY TRANSPORT PHENOMENA

• PREDICTIVE MODELS & CORRELATIONS

Natural Circulation Experiments

• INTEGRAL SYSTEM TESTS • SEPARATE EFFECTS TESTS • TEST FACILITY SCALING METHODS

Integral System Phenomena & Models

• SYSTEM MASS, MOMENTUM AND ENERGY TRANSPORT PHENOMENA

• N/C STABILITY • STABILITY ANALYSIS TOOLS • PASSIVE SAFETY SYSTEM DESIGN

Reliability & Advanced Computational Methods

Experiments • PASSIVE SYSTEM RELIABILITY • CFD FOR NATURAL CIRCULATION

FLOWS

Introduction

• GLOBAL NUCLEAR POWER • ROLE OF N/C IN ADVANCE DESIGNS • ADVANTAGES & CHALLENGES

Opening Session

• INTRODUCTIONS • ADMINISTRATION • COURSE ROADMAP

Local Transport Phenomena & Models

• LOCAL MASS, MOMENTUM AND ENERGY TRANSPORT PHENOMENA

• PREDICTIVE MODELS & CORRELATIONS

Natural Circulation Experiments

• INTEGRAL SYSTEM TESTS • SEPARATE EFFECTS TESTS • TEST FACILITY SCALING METHODS

Integral System Phenomena & Models

• SYSTEM MASS, MOMENTUM AND ENERGY TRANSPORT PHENOMENA

• N/C STABILITY • STABILITY ANALYSIS TOOLS • PASSIVE SAFETY SYSTEM DESIGN

Reliability & Advanced Computational Methods

Experiments • PASSIVE SYSTEM RELIABILITY • CFD FOR NATURAL CIRCULATION

FLOWS

Introduction

• GLOBAL NUCLEAR POWER • ROLE OF N/C IN ADVANCE DESIGNS • ADVANTAGES & CHALLENGES

Opening Session

• INTRODUCTIONS • ADMINISTRATION • COURSE ROADMAP

Roadmap for the Training Course Roadmap for the Training Course on NC in Water-Cooled Reactorson NC in Water-Cooled Reactors

CONTENTCONTENT

2/47

NCFM DEFINITION AND ROLENCFM DEFINITION AND ROLE

(CONNECTION WITH) THE SCALING ISSUE(CONNECTION WITH) THE SCALING ISSUE

DERIVATION OF THE NCFM (part of scaling activity)DERIVATION OF THE NCFM (part of scaling activity) - - The ITFThe ITF - - The NC BICThe NC BIC - The experimental scenario- The experimental scenario - - The scalThe scalee dependent parameters dependent parameters - The capability of the codes in predicting NC- The capability of the codes in predicting NC - The scale-up of data: - The scale-up of data: 1 NC, use of TH codes, NC regimes NC, use of TH codes, NC regimes - The NCFM - The NCFM

APPLICATION OF THE NCFMAPPLICATION OF THE NCFM

CONCLUSION CONCLUSION

APPENDIX 1: MAX POWER REMOVAL BY NCAPPENDIX 1: MAX POWER REMOVAL BY NC

THE NCFM DEFINITION AND ROLETHE NCFM DEFINITION AND ROLE

2/47

THE NCFM ACRONYM:THE NCFM ACRONYM:

NATURAL CIRCULATION FLOW MAP FOR PWR SYSTEMS

WHAT IS NCFM?WHAT IS NCFM?

NCFM IS AN ‘ENGINEERING’ TOOL DERIVED FROM ITF MEASURED DATA FOR 1 AND 2 NATURAL CIRCULATION

THE NCFM ROLETHE NCFM ROLE:

IT CAN BE USED TO SUPPORT:• SCALING STUDIES (but also derived from scaling related data)• DESIGN/OPTIMISATION OF NC SYSTEMS• VALIDATION OF COMPUTATIONAL MODELS (codes, nodalisation, etc.)• JUDGING THE NC PERFORMANCE

The framework:The framework:THE TRANSIENT PERFORMANCE OF LWR NPP (HIGH POWER, HIGH PRESSURE, LARGE GEOMETRY)

The origin of the problem:The origin of the problem:THE IMPOSSIBILITY TO PERFORM RELEVANT

EXPERIMENTS AT FULL SCALE (POWER, PRESSURE, GEOMETRY)

THE SCALING ISSUETHE SCALING ISSUE

5/61

The goal of a scaling analysisThe goal of a scaling analysis

TO ENSURE (OR TO SUPPORT) THE PREDICTABILITY OF LWR NPP TRANSIENT SCENARIOS

The historical ways to address the issueThe historical ways to address the issue

FLUID BALANCE EQUATIONS (deriving non-dimensional parameters)

SEMI-EMPIRICAL MECHANISTIC EQUATIONS (deriving non-dimensional parameters)

TO PERFORM EXPERIMENTS (at different scales)

TO DEVELOP, TO QUALIFY, TO APPLY CODES (by showing capabilities at different scales)

6/61


The target of a scaling analysisThe target of a scaling analysis

THE GLOBAL SYSTEM PERFORMANCE (e.g. the prediction of pressure behavior during blow-down, following LOCA)

THE PERFORMANCE OF A COMPONENT OR OF A ZONE OF THE SYSTEM (e.g. pump performance during LBLOCA, or CL-DC mixing following ECCS injection)

THE ‘LOCAL’ EVOLUTION OF THERMALHYDRAULIC PHENOMENA (e.g. the CHF occurrence in fuel rods, the CCFL at the UTP following UP injection, the TPCF at the break)

7/61

MACROSCALEMACROSCALE

COMPONENT SCALECOMPONENT SCALE

MICROSCALEMICROSCALE


The objectives of a scaling analysisThe objectives of a scaling analysis

TO PROVE THE CAPABILITY IN SIMULATING AN ASSIGNED PHENOMENON

TO DESIGN A TEST FACILITY

TO PROVE THE SCALING CAPABILITY OF A TH MODEL OR OF A TH (SYSTEM) CODE

8/61


A SPECIAL ISSUE OF THE J. ‘NUCLEAR ENGINEERING AND DESIGN’ DEVOTED TO SCALING IN 1998 – MORE THAN 300 PAGES & 12 PAPERS

9/61

THREE LEVELS OF SCALING ANALYSIS PROPOSED BY ISHII et al.:THREE LEVELS OF SCALING ANALYSIS PROPOSED BY ISHII et al.:

- Integral scaling- Integral scaling

- Control volume scaling- Control volume scaling

- Local phenomena scaling- Local phenomena scaling

THE AUTHORS END UP WITH MORE THAN 200 SCALING FACTORS, BUTTHE AUTHORS END UP WITH MORE THAN 200 SCALING FACTORS, BUT

“… The design cannot completely satisfy all the scaling requirements. thus, scaling distortions are inevitable … Distortions are encountered for two major reasons:

- difficulty to match the local scaling criteria

- lack of understanding of the local phenomenon itself.”


10/61

A SCALING STUDY WAS COMPLETED BY BANERJEE et al., FOCUSED ON A SCALING STUDY WAS COMPLETED BY BANERJEE et al., FOCUSED ON THE THE ROSAROSA, , SPESSPES AND AND OSU OSU FACILITIES, THAT SIMULATE THE FACILITIES, THAT SIMULATE THE AP-600 AP-600 NPPNPP. ABOUT 30 SCALING PARAMETERS WERE FOUND. AN EXCERPT . ABOUT 30 SCALING PARAMETERS WERE FOUND. AN EXCERPT FROM A LARGER TABLE IS GIVEN.FROM A LARGER TABLE IS GIVEN.

The scaling study identified phenomena in general agreement with the PIRT. Notwithstanding the differences in the table, “…the magnitude of the non-dimensional coefficients were similar for the ITF and the AP-600 … the same ‘important’ processes occurred in the ITF as might be expected in the AP-600.”

A SPECIAL ISSUE OF THE J. ‘NUCLEAR ENGINEERING AND DESIGN’ DEVOTED TO SCALING IN 1998 – MORE THAN 300 PAGES & 12 PAPERS


A) PURSUING A SYSTEMATIC APPROACH IMPLIES

1) ID and characterization of thermal-hydraulic phenomena

2) Writing equations (fluid balance & mechanistic) at macro-scale, component-scale and micro-scale levels and deriving suitable non-dimensional parameters

3) Achieving ‘qualified’ functional relationships between phenomena and scale

B) SCALING APPROACHES AVAILABLE (Zuber, Ishii, etc.)

C) COMPREHENSIVE SOLUTION NOT ACHIEVED YET (Ishii et al., J. NED 1998, see also below)

11/61


D) IN GENERAL TERMS: two-phase, transient TH phenomena, are affected by local system parameters that do not appear into balance equations or into ‘scalable’ mechanistic models:

12/61

TPCF is affected (at least) by phenomena like ‘vapor pull through’ & sub-cooled vapor formation by ‘sharp edge cavitation’. These are not reproducible at a different scale. In addition, heat losses, mixture levelformation and fluid temperature stratification cannot be scaled up.


13/61

E) THE ATTEMPT TO SCALE UP ALL TH PHENOMENA (e.g. TPCF, CCFL, nat. circ., CHF, DPi, ) RELEVANT DURING AN ASSIGNED TRANSIENT IN LWR NPP, IS UNSUCCESSFUL:

A myriad scaling factors

Counterfeiting values

THEREFORE,

• HIERARCHY IN SCALING FACTORS (as recognized by Zuber)

• AN OVERALL SCALING STRATEGY

ARE NEEDED


14/61

DERIVATION OF THE NCFM / THE ITFDERIVATION OF THE NCFM / THE ITF

THE ITF (AND THE NPP) AT THE ORIGIN OF THE NC DATABASE

15/61

DERIVATION OF THE NCFM / THE ITFDERIVATION OF THE NCFM / THE ITFA MORE DETAILED VIEW OF A SINGLE ITF: THE LOBI/MOD2

16/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE NC BIC THE NC BIC

HARDWARE CHARACTERISTICS OF SELECTED ITF AND DOEL NPP

17/61

DERIVATION OF THE NCFM / DERIVATION OF THE NCFM / THE NC BICTHE NC BIC

BIC VALUES FOR SELECTED ITF EXPERIMENTS – 1 OF 2

18/61

DERIVATION OF THE NCFM / DERIVATION OF THE NCFM / THE NC BICTHE NC BIC

BIC VALUES FOR SELECTED ITF EXPERIMENTS – 2 OF 2

Quantities defined in previous slide; Including DOEL NPP

19/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE EXP SCENARIOTHE EXP SCENARIO

THE NC SCENARIO FROM DRAINING PS MASS INVENTORY – 1 of 2

1) Core Flowrate; 2) Mass Inventory and Rod Surface Temperature; 3) DP oscillations; 4) Primary Pressure and SG DP

1

2

3

4

20/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE EXP SCENARIOTHE EXP SCENARIO

THE NC SCENARIO FROM DRAINING PS MASS INVENTORY – 2 of 2

5) Density in HL; 6) Fluid velocities in IL and BL

5

6

21/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE SCALE DEPENDENCETHE SCALE DEPENDENCE

THE PARAMETERS TO BE CONSIDERED IN SCALING

1) & 2) PS volume; 3) Thermal load on individual U-Tubes (various L/D); 4) PS pressure

12

3

4

KvKv5 KvKv5

pp

Kw/UTKw/UT5

22/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE SCALE DEPENDENCETHE SCALE DEPENDENCE

THE PARAMETERS THAT HAVE SMALL SCALE EFFECT

1) Length over diameter in HL; 2) Core power; 3) Presence of core bypass;4) Core active height

1

2

3

4

23/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE CODE CAPABILITIESTHE CODE CAPABILITIES

THE TH SYS CODES ARE CAPABLE TO PREDICT RELEVANT NC PARAMETERS – TYPICAL NODALISATION SKETCH

24/61


THE TH SYS CODES ARE CAPABLE TO PREDICT RELEVANT NC PARAMETERS – EXP/CALC BIC DATASET

25/61


THE TH SYS CODES ARE CAPABLE TO PREDICT RELEVANT NC PARAMETERS – NODALISATION RESOURCES

26/61


THE TH SYS CODES ARE CAPABLE TO PREDICT RELEVANT NC PARAMETERS

1) Initial steady-state (fluid temperature vs length); 2) Density in HL vs time; 3) DP across SG UT in PS vs time; 4) Core flowrate vs PS mass inventory.

1

2

3

4

27/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE ATTEMPT TO SCALE-UPTHE ATTEMPT TO SCALE-UP

A SIMPLIFIED APPROACH TO SCALE-UP 1 NC

Starting from the definition of driving and resistant forces (eqs. 1), one obtains an expression for core flowrate, eq. 4, that depends upon KvKv and pressure drops(distributed and localized as given by the eq. 3 and the C6 coefficient in eq. 4).

1

2

3

4

11/61


A SIMPLIFIED APPROACH TO SCALE-UP 1 NC: RESULTS

A core flowrate, function of Kv is derived (1 NC) and is compared with exp data & with results of code calculations.

29/61


A SIMPLIFIED APPROACH TO SCALE-UP 2 NC: RESULTS

The attempt to scale-up 2 NC is not as succesfull: a) “extrapolation” formulas cannot be easily derived; b) the application of qualified code-nodalisation producesthe results shown in the figures.

30/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE NC REGIMESTHE NC REGIMES

THE (SCALE INDEPENDENT) NC REGIMES

1 NC, 2 NC and max 2 NC, 2 NC instabilities (siphon condensation),reflux condensation, dryout occurrence can be distinguished in the figure,items 1 to 5

1 2 3 4 5

31/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE NCFM THE NCFM

THE ROUGH DATA GATHERING (TO DERIVE NCFM)

Collecting of rough ITF data does not provide suitable information

32/61

DERIVATION OF THE NCFM /DERIVATION OF THE NCFM / THE NCFM THE NCFM

THE DATA BASE HAS BEEN REPORTED IN THE “G/P VS RM/V” PLANE

The bounding of the database constitutes the NCFM. This is used for • scaling studies• design/optimisation of nc systems• validation of computational models (codes, nodalisation, etc.)• judging the NC performance

RM/V (kg/m3)

200300400500600700800900

G/P

(kg

/MW

s)

0

5

10

15

20

25

Bethsy 2%Bethsy 5%LobiLstf 2%Lstf 5%SemiscalePkl 2%Pkl 3%Spes 1 %Spes 5 %

RM/V (kg/m3)

200300400500600700800900G

/P (k

g/M

Ws)

0

5

10

15

20

25

NCFMNCFM

33/61

APPLICATION OF THE NCFM APPLICATION OF THE NCFM

Characteristics of NPP considered for the application of the NCFM

1PWR

2PWR

3PWR

4VVER

5EPR

6AP-600

7EP-1000

Nominal Power (MW) 1877 870 2733 3000 4250 1972 2958Primary System volume (m3) 167 150 330 359 459 211 339

SG type U-Tubes U-Tubes Once-Through Horizontal U-Tubes U-Tubes U-Tubes

No. of loops 2 4 2 4 4 2 3

No. of pumps 2 4 4 4 4 4 6

Nominal mass inventory (Mg) 108 108 224 240 307 145 227

Nominal Core Flow (Kg/s) 9037 3150 17138 15281 20713 8264 14507

Pressurizer and SG pressure (MPa)

15.66.

14.03.1

15.06.4

15.76.3

15.57.2

15.55.5

15.86.4

34/61


Characteristics of ITF considered for the application of the NCFM

Pactel

(original) Pactel

(with CMT) ° RD14M

Reference reactor and power (MW) WWER-440 1375

WWER-440 1375

CANDU 1800

No. of rods 144 144 70 No. of SG 3 3 2 SG type Horizontal Horizontal U-Tubes Actual Kv + 1/433 1/462 1/378

35/61


RESULT – 1 OF 3

RM/V (kg/m3)

200300400500600700800900

G/P

(kg/M

Ws)

0

5

10

15

20

25

30

35

WWERPWR-3EPRPWR-2

The predicted NC performance of VVER-1000, PWR-NPP 2 and EPR is consistent with the derived NCFM. ‘Lower’ NCP for PWR-NPP 3.

36/61


RESULT – 2 OF 3

The predicted NC performance of EP-1000, PWR-NPP 1 and AP-600 is consistent with the derived NCFM

RM/V (kg/m3)

200300400500600700800900

G/P

(kg

/MW

s)

0

5

10

15

20

25

PWR - 1EP-1000

AP-600

11/61


RESULT – 3 OF 3

Suitable NC performance is obtained for VVER-440 simulator and not for CANDU simulator

11/61


SUMMARY OF RESULT

Evaluation of NCP shall be considered together with quality of the available DB and of the adopted computational tools

NPP or ITF Quality of

starting DB

Quality of adopted

tools

Evaluation of

NCP PWR-1 Y Y S PWR-2 N Y S PWR-3 Y Y NS WWER-1000 Y Y S EPR N Y S AP-600 Y Y S EP-1000 N N - Pactel Y - S Pactel with CMT

Y - S

RD14M N.A. - - Y Confirmed N Not Confirmed N.A. Not Available - Not applicable S Suitable (for NCP) NS Not Suitable

39/61

APPLICATION OF THE NCFM APPLICATION OF THE NCFM ATUCHA-1 PHWR – Ferreri et al. - Nodalisation for SET II

40/61


ATUCHA-1, Ferreri et al.

Outline of performed calculations – NPP qualified Relap5 input deck is usedto evaluate the NCP of the CNA-1

# RUN Power MW to Primary

MOD-UP open

MOD line volumes

PRZ closes

NOTES

1 Test26 5% - 59.1 No No Yes 2 Test27 4% - 47.3 No No Yes 3 Test28 3% - 36.1 No No Yes 4 Test30 2% - No No Yes 5 Test31 3% - Yes No Yes

SET-I

6 Test35 3% - Yes Yes Yes SET-II 7 Test01-N 3% - Yes Yes No NA-S.A. SET-III 8 Test36 5% - 55.5 Yes Yes Yes 9 Test33 4% - 47.3 Yes No Yes 10 Test34 3% - 35.9 Yes Yes Yes

SET-II

11 Test02-N 4% - 47.0 Yes Yes No 12 Test03-N 5% - 58.9 Yes Yes No

NA-S.A. SET-III

13 Test04-N 3% - 35.9 Yes Yes No SBLOCA

SET-III

11/61


ATUCHA-1 PHWR, Ferreri et al.

Results from SET-I

11/61



Results from SET-II

11/61



Results from SET-III

11/61


PKL III experiment F1.2. Del Nevo et al. (2006)

Natural circulation maps

0

5

10

15

20

25

01002003004005006007008009001000

RM/V [Kg/m^3]

G/P

[Kg/

MW

s]

Experimental Data

11/61

APPLICATION OF THE NCFM – BWR NC DATABASEAPPLICATION OF THE NCFM – BWR NC DATABASE

11/24

DATABASE FROM: NPP measurements (N), ITF (I) & Calculations (C)

N

I

N

N

N

N

C

C

C

C

C

45/61

APPLICATION OF THE NCFM – BWRAPPLICATION OF THE NCFM – BWR

11/24

BWR NPP DATA & RBMK qualified calculation

NCNC

46/61

47/61

REVISITED REVISITED RD-14mRD-14m APPLICATION ( APPLICATION (CANDUCANDU RELATED) RELATED)

Step 0: Development of Relap5 RD-14m nodalisation

1636 hydraulic nodes

11788 meshes for conduction heat transfer

17/24


Step 1: Analysis of LBLOCA test B-9401 (IAEA framework)

Rod surface temperaturePCT location

System (header 6)pressure

48/61

11/24


Step 2: full demonstration of nodalization qualification

“Steady-state”level

“On-Transient”Level (by FFTBM)

11/24


Step 3: Calculation of NC scenario

Ch-to-Ch NC

“SG-NC”

Distinction between:SG NC SG NC (NCFM applicable)(NCFM applicable)Ch-to-Ch NC Ch-to-Ch NC (NCFM not applicable)(NCFM not applicable)

RM/V > ~ 500

51/61

CONCLUSIONSCONCLUSIONS

A SYSTEM SCALING STUDY WAS THE PRECURSOR FOR THE DERIVATIONOF THE NCFM.

NCFM GATHERS ITF PWR SIMULATORS DATA.

NCFM CAN BE USED TO SUPPORT:• SCALING STUDIES,• DESIGN/OPTIMISATION OF NC SYSTEMS,• VALIDATION OF COMPUTATIONAL MODELS, • JUDGING THE NC PERFORMANCE.

NCFM APPLICATION SHOWS GOOD NC PERFORMANCE OF CONSIDEREDNPP (E.G. VVER-1000 AND ATUCHA PHWR). “LOWER” NC PERFORMANCEIS PREDICTED FOR B&W PWR AND CANDU (HOWEVER, THE EVALUATIONIS AFFECTED BY THE QUALITY OF THE AVAILABLE DB AND BY THE USED COMPUTATIONAL TOOLS).

BY-PRODUCTS OF THE ACTIVITY BRINGING TO THE NCFM, E.G MAX POWERREMOVABLE IN NC IN PWR SYSTEMS IN 1NC AND 2NC (SEE APP. 1)

52/61

APPENDIX 1 – APPENDIX 1 – THE MAX POWER REMOVAL BY NCTHE MAX POWER REMOVAL BY NC

ADDITIONAL RESULT FROM THE NCFM DB

The objective is an estimation of the maximum thermal power removable by NC in PWR systems. This may be relevant in the unlikely event of ATWS-MCP trip and in the design of NC based new reactors. However, no care is given to the TH-NK feedback.

The analysis is carried out into two parts:a) related to ITFb) related to a PWR.

In all cases, the primary system pressure and the SG conditions (pressure, level and FW temperature) are kept constant at the nominal values if not differently specified. The MCP are at zero speed and the locked rotor hydraulic resistance of the impeller is taken into account. The core power and the FW flow are consistently varied.

53/61


Removable power by Natural Circulation in ITF

ITF Core power when void

achieves 0.1 at the upper core level (°)

Core power when dryout

occurs (°)

Void at the upper core level

when dryout occurs

Primary system mass inventory

at dryout (°)

G/P at dryout

(Kg/MWs)

RM/V at dryout (Kg/m3)

Bethsy 15 70 0.8 69 1.12 475 Lobi 20 70 0.7 80 1.23 570 Lstf 10 30 0.9 62 1.87 480 Spes 15 50 0.6 75 1.29 528 (°) % of the nominal operational value


11/61


Removable power by Natural Circulation in ITF: NC conditions relevant for calculating the maximum removable

thermal power in the NPP and in the ITF.


11/61


Removable power by Natural Circulation in ITF: core flowrate versus core power at different pressure and temperature related boundary conditions


56/61

ADDITIONAL RESULT FROM THE NCFM DB – PWR-1 calc. No. ID. P

MW/% G

(Kg/s)/% SG PRE

MPa RM

KgE5/% PS PRE

MPa UP T/Tsat

K UP Void

- G/P

Kg/sMW RM/V Kg/m3

1# KK01 1876/100 9037/100 6.1 1.08/100 15.6 598/618 0. 4.82 647 2^ KK01 56/3.0 520/5.8 8.1* 1.08/100 13.6 577/608 0. 9.28 647 3 KK01 376/20. 930/10.3 6.0* 1.08/100 15.4 615/617 0. 2.47 647 4 KN03 469/25. 1016/11.2 6.0* 1.07/99.1 16.2 620/620 0.10 2.17 641 5 KN04 563/30. 1140/12.6 6.0* 1.01/94.0 16.2 620/620 0.21 2.02 605 6 KN05 938/50. 1370/15.1 6.0* 0.92/85.0 16.2 620/620 0.47 1.46 550 7 KN07 1032/55. 1396/15.4 6.0* 0.90/83.3 16.2 620/620 0.48 1.35 539 8 KN08 1126/60. 1428/15.8 6.0* 0.89/82.9 16.2 620/620 0.49 1.27 536 9 KN09 1219/65. 1450/16.0 6.0* 0.88/82.0 16.2 620/620 0.51 1.19 529 10§ KN10 1313/70. 1490/16.4 6.0* 0.87/80.8 16.2 620/620 0.62 1.13 523 11 KL10 1032/55. 1396/15.4 3.5* 0.99/91.4 16.2 620/620 0.44 1.35 592 12 KL10 1313/70. 1650/18.3 3.5* 0.95/88.2 16.2 620/620 0.49 1.26 571 13§ KL12 1500/80 1492/16.5 3.5* 0.91/84.6 16.2 620/620 0.60 0.99 547 14§ KL11 1688/90. 1523/16.8 3.5* 0.87/80.4 16.2 620/620 0.77 0.90 520 15 LL11 1032/55. 1365/15.1 3.5** 1.01/93.9 16.2 620/620 0.31 1.32 608 16§ LL11 1688/90. 1525/16.9 3.5** 0.93/86.3 16.2 620/620 0.57 0.90 556 17 LL12 1500/80. 1380/15.3 3.5** 0.96/88.8 16.2 620/620 0.49 0.92 575 18 LL13 1032/55. 1300/14.4 2.5** 1.04/96.3 16.2 620/620 0.20 1.26 623 19 LL13 1500/80. 1750/19.4 2.5** 1.00/92.3 16.2 620/620 0.48 1.17 597 20 LL14 1688/90. 1460/16.2 2.5** 0.97/89.4 16.2 620/620 0.50 0.87 578 21§ LL15 1876/100. 1587/17.5 2.5** 0.94/86.6 16.2 620/620 0.63 0.85 560 22 HL15 1032/55. 1290/14.3 2.5** 1.09/101. 18.5 631/633 0.01 1.25 652 23§ HL15 1876/100. 1630/18.1 2.5** 0.97/89.3 18.5 633/633 0.58 0.87 578 24 HL16 1032/55. 1295/14.3 2.5+ 1.09/101. 18.5 594/633 0. 1.25 652 25§ HL16 1876/100. 1630/18.1 2.5+ 0.99/91.4 18.5 633/633 0.50 0.87 590


57/61

ADDITIONAL RESULT FROM THE NCFM DB – PWR-1 calc.

NOMENCLATURE FOR THE TABLE IN THE PREVIOUS SLIDE


Nomenclature ID Calculation identification § Dryout occurrence G Core flowrate # Nominal working conditions for the system P Core Power ^ Reference NC result PRE Pressure * FW temperature same as in nominal condition PS Primary System ** FW temperature set at 363 K RM Mass Inventory in PS + FW temperature set at 333 K T Fluid Temperature + FW G set at 1.3 times the equilibrium value Tsat Saturation temperature UP Upper Plenum Void Void fraction

11/61


Primary system mass inventory versus core power at different pressure and temperature boundary conditions (ITF and PWR-1)

P (%)

0 20 40 60 80 100 120

RM

(%

)

20

30

40

50

60

70

80

90

100

110

Nominal conditions NCNominal conditions NC (dryout occurrence)Low SG pressure NCLow SG pressure NC (dryout occurrence)NC at low SG pressure and low FW temp.NC at low SG pressure and low FW temp. (dryout occ.)NC at low SG pressure and high PS pressure (dryout occ.)ITF max NC with dryout ITF NC experimental data

PWR-1&

ITF


(not properly scaled)ITF data

11/61


Removable core power at different values of steam generator pressures.

SG pressure (MPa)

2 3 4 5 6 7 8

Core

pow

er (%

)

0

20

40

60

80

100

120

no dryout occurrencedryout occurrence

PWR-1


11/61



Power removal by NC largely depends upon PS and SS TH boundary conditions.

Two TH thresholds are considered and no evaluation is given of the TH-NK coupling:

a) the void formation in the core (PWR behaves like a BWR) b) overpassing the CHF.

When PS and SS BIC are kept close to their nominal values:NC is effective for removing up to around 20% of core power, 2NC is effective for removing up to 70% of core power avoiding the

occurrence of the CHF.

100% core power can be removed in 2 NC, provided the SG pressure and the FW temperature are lowered to values of the order of 3 MPa and 100 °C, respectively. An increase of primary pressure also brings to increase the power removal capability by natural circulation.

61/61

APPENDIX 2 APPENDIX 2

REFERENCE PAPERS

D’Auria F., Galassi G.M., Vigni P., Calastri A. “Scaling of Natural Circulation in PWR Systems”, J. Nuclear Engineering and Design, col 132 1991, pp 187-205

D’Auria F., Frogheri M., Leonardi M. “Natural Circulation Performance in Western type and Eastern type PWR”, Simulator Multiconference, San Diego (CA), April 11-13, 1994

D’Auria F., Galassi G.M., Frogheri M “Natural Circulation Performance in Nuclear Power Plants, 2nd Conf. of the Croatian Nuclear Society, Dubrovnik (HR), June 17-19, 1998

D'Auria F., Frogheri M., Monasterolo U. "Removable power by natural circulation in PWR systems“ - ASME-JSME Int. Conf. on Nuclear Engineering (ICONE-5) - Nice (F) May 26-30 1997 (ICONE5-2431)

Ferreri J. C., Mazzantini O., Ventura M. A., Rosso R.D., D'Auria F. "Natural circulation in the CAN-I PHWR NPP characterization based on flow maps"10th Int. Top. Meet. on Nuclear Reactor Thermalhydraulics (NURETH-10), Seoul (South Korea), Oct. 5-9 2003 D'Auria F., Frogheri M. "Use of Natural Circulation Flow Map for assessing PWR performance” Eurotherm Sem. No. 63: Single and Two-Phase Natural Circulation, Genova (I), Sept. 6-8 1999

the use of the natural circulation flow map

Documents

scaling capability

scaling analysisto

scaling distortions

scaling parameters

scaling issuea scaling

scaling activity

scaling studies

scaling factors