overview of melcor activities in ciemat (2012) · european melcor user group, 2013 unit of nuclear...

European MELCOR User Group, 2013

Stockholm, May 2 - 3, 2013Unit of Nuclear Safety Research

OVERVIEW OF MELCOR ACTIVITIES

IN CIEMAT (2012)

C. López, M. García, E. Fernández, L.E. Herranz

Unit of Nuclear Safety Research

CIEMAT, SPAIN



Scenarios Addressed

• Plant analysis

Spanish NPP (CSN) MELCOR 2.1

• Fuel degradation in the presence of air

SFP (OECD-SFP project) MELCOR 1.8.6 YV 3084 SFP

BWR:

Spanish NPP (ARTIST-Ext ) MELCOR 2.1

PWR:

BSAF (CSN, OECD project) MELCOR 2.1



Plant analysis BWR, PWR

1.8.4 1.8.5 1.8.6 2.1�� SNAP�� SNAP

�COR�Converter�COR�Converter

��

Inputs updating:

Automatic conversion to 2.1:

• MELGEN ��

• MELCOR �� “by hand”

Automatic conversion to 2.1:

• MELGEN ��

• MELCOR �� “by hand”



Execution

M2.1.3226 M2.1.4206 M2.1.4803

BWR ��

PWR ��

Post-processing:

PTFread1.76.xla ��

PTFread1.77.xla ��

PTFread *.xlam Not supported (Office 2003)



• Corruption of files sent by e-mail:

license.request → *.zip

• Post-processing of MELCOR 2.1 case with PTFread1.76:

- water density

Others:

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30 40

time [hr]

Mas

s [k

g/m

**3]

CVH-RHO.1.200

Output ��Output ��



1.E-02

1.E+01

1.E+04

1.E+07

1.E+10

1.E+13

0 5 10 15 20time [hr]

Mas

s [k

g]

RN2-DFBBT-22-aRN2-DFBBT-152-aRN2-DFBBT-10-aEstimate DF pool




- water density

- Cumulative DF

SRV: FL 362

DC: FL 20

Others:

RN2-DFBBT-3622-a?RN2-DFBBT-202-a?RN2-DFBBT-3622-a?RN2-DFBBT-202-a?






- water density

- Cumulative DF

Others:

?



THANK YOU FOR YOUR ATTENTION!!



SBOIC11

SBOnoICSBOICad SBOSVSBOSRVop

IC S-RVs

LOOPIC11

1. BWR: CSN Spanish NPPBWR-Mark I

1400 MWth

Systems analyses:Unit 1 Fukushima-like scenario



Core &

RPVPCV

ReactorBuilding

Total

COR cells 41 - - 41

CVs 6 3 11 20

FLs 8+5 4+3 15 35

HSs 14 7 25 46

Z1: 0.00

Z2: 0.884

Z3: 2.371

Z4: 3.105

Z5: 3.840

Z6: 4.575

Z7: 4.715

Z8: 5.204

Z9: 6.100

Z10: 6.997

Z11: 7.894

Z12: 8.791

9.185

4

CV 330Bypass

CV 340Core

Channel

CV 320Lower Plenum

BAF

TAF

SRVs

SVs �� FL (Valve, TF)

Failures

IC �� CF (Steam Sink)

(Water Source)

1. BWR: CSN



0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20time (h)

DW

pre

ssu

re (

MP

a)

SBO_IC11

SBO_ICad

WW vent open

IC Effect SV Effect

Time shift

IC performance → late and slower degradation of fuel.

→ similar Containment evolution

0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

time (h)D

W P

ress

ure

(M

pa)

SBO_IC11SBO_SV

Steam

Non condensable

DW FailDW Fail + Vent

SV operation → similar fuel degradation.

→ different Containmentevolution.

1. BWR: CSN



2. BWR: CSN, BSAF ProjectStarting point: previous BWR NPP

• Detailed plant model

COR: 4 x 13

BAF

TAF

COR: 3 x 12



WW DW

2. BWR: CSN, BSAF Project



Input development of the 3 NPP→ Excel worksheet

2. BWR: CSN, BSAF Project



Focus: Implementation of the ARI3SG correlation in MELCOR 2.1:

3. PWR: ARTIST-Ext Project

Scope: -“Near field” deposition (break stage)

-“Dry conditions” (no pool scrubbing)

4

12

12

p

TBStk

StkRe

009.0exp47.0 ⋅

⋅−⋅=η

~20

m

Objective: Aerosol retention in the Secondary Side of a Steam Generator.

ARI3SG



Scenario:SGTR:

- Double-ended rupture SG.

-SG PORV failed Open.

-Bypass sequence.


Spanish PWR: 2614 MWth3 loops

- Filter implementation

by Control Function

Approach:

ARI3SG

Filter



0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40Time (h)

cp1_CVH-LIQLEV.300

SG Top

SG BottomTube breach

Top tube bundle

0

2

4

6

8

10

12

14

16

18

20

0

SG

wat

er le

vel (

m)

SG BottomTube breach


Dry

ONGOING ANALYSES



SFP tests:

• Complete LOCA in SFPools• BWR/PWR fuel assemblies• Zr air oxidation leading to cladding ignition

2 Scenarios modeled:

4. SFP: OECD-SFP Project

• 1x1

• 1x4

1x1:



SFP-PWR 1X4

GasCirculation

NaturalConvection

ForcedConvection

Measurements

Zero rates (R2)

Materialproperties

Radiationmodeling

Materialemissivities

Viewfactors

Systemproperties

Cp: MgO, SS, Al

ZrO2thickness

Gapthickness

Rackas HS

SS, ZrO2

Arbitraryradiation paths

(NNHTR)CL-1 → RK-1 → CL-2 → RK-2

Gap modelCL inner surf.emissivity set

to zero

FCELRFSSCN

Low values �� ignition in R1

4. SFP:



PWR 1x1PWR 1x1 PWR 1x4PWR 1x4

4. SFP: OECD-SFP Project

Center

• The ignition onset time well captured.• Discrepancies on ignition onset location or propagation.• The ignition onset time well captured.• Discrepancies on ignition onset location or propagation.

overview of melcor activities in ciemat (2012) · european melcor user group, 2013 unit of nuclear...

Documents