Mass [kg/m**3]

(1)

OVERVIEW OF MELCOR ACTIVITIES IN CIEMAT (2012)

C. López, M. García, E. Fernández, L.E. Herranz Unit of Nuclear Safety Research

CIEMAT, SPAIN

(2)

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

(3)

Plant analysis BWR, PWR

1.8.4 1.8.5 1.8.6 2.1

SNAP COR SNAP

Converter COR

Converter

Inputs updating:

Automatic conversion to 2.1:

• MELGEN

• MELCOR “by hand”

Automatic conversion to 2.1:

• MELGEN

• MELCOR “by hand”

(4)

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)**

(5)

• 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]

Mass [kg/m**3]

CVH-RHO.1.200

Output

(6)

1.E-02 1.E+01 1.E+04 1.E+07 1.E+10 1.E+13

0 5 time [hr] 10 15 20

Mass [kg]

RN2-DFBBT-22-a RN2-DFBBT-152-a RN2-DFBBT-10-a Estimate DF pool

• Corruption of files sent by e-mail:

license.request → *.zip

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

- 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?

(7)

• Corruption of files sent by e-mail:

license.request → *.zip

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

- water density - Cumulative DF

Others:

?

(8)

THANK YOU FOR YOUR ATTENTION!!

(9)

SBO

_IC11

SBO

_noIC

SBO

_ICad

SBO

_SRVop

SBO

_SV

IC S-RVs

LOOP

_IC11

1. BWR: CSN

Spanish NPP BWR-Mark I

1400 MWth

Systems analyses:

Unit 1 Fukushima-like scenario

(10)

Core

&

RPV

PCV Reactor

Building 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 330 Bypass CV 340

Core Channel

CV 320 Lower Plenum

BAF TAF

SRVs

SVs FL (Valve, TF) Failures

IC CF (Steam Sink) (Water Source)

1. BWR: CSN

(11)

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)

DW pressure (MPa)

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)

DW Pressure (Mpa)

SBO_IC11 SBO_SV Steam

Non condensable

DW Fail DW Fail + Vent

SV operation → similar fuel degradation.

→ different Containment evolution.

1. BWR: CSN

(12)

2. BWR: CSN, BSAF Project

Starting point: previous BWR NPP

• Detailed plant model

COR: 4 x 13

BAF TAF

COR: 3 x 12

(13)

WW DW

2. BWR: CSN, BSAF Project

(14)

Input development of the 3 NPP→ Excel worksheet

2. BWR: CSN, BSAF Project

(15)

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 2 1

1 2

p

TB Stk

Stk 009 Re

. 0 exp 47 .

0 ⋅























⋅

−

⋅

= η

~ 2 0 m

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

ARI3SG

(16)

Scenario:

SGTR:

- Double-ended rupture SG.

-SG PORV failed Open.

-Bypass sequence.

3. PWR: ARTIST-Ext Project

Spanish PWR: 2614 MWth 3 loops

- Filter implementation by Control Function

Approach:

ARI3SG

Filter

(17)

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

cp1_CVH- LIQLEV.300 SG Top

SG Bottom Tube breach

Top tube bundle

0 2 4 6 8 10 12 14 16 18 20

0

SG water level (m)

SG Bottom Tube breach

3. PWR: ARTIST-Ext Project

Dry

ONGOING ANALYSES

(18)

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:

(19)

SFP-PWR 1X4

Gas Circulation

Natural Convection

Forced Convection

Measurements Zero rates (R2)

Material properties

Radiation modeling

Material emissivities

View factors System

properties

C_p: MgO, SS, Al

ZrO

₂

thickness

Gap thickness Rack

as HS

SS, ZrO₂

Arbitrary radiation paths

(NNHTR)

CL-1 → RK-1 → CL-2 → RK-2

Gap model CL inner surf.

emissivity set

FCELR

FSSCN Low values ignition in R1

4. SFP:

(20)

PWR 1x1

PWR 1x1 PWR 1x4 PWR 1x4

4. SFP: OECD-SFP Project

Center