T.G. Theofanous

Center for Risk Studies and Safety University of California, Santa Barbara

STEAM EXPLOSIONS

Risk Complexity

An Approach Based on Key Physics (ROAAM)

m-FLUID PREMIXTURE

vO, PO

COOLANTVAPORFUEL

(melt)NON-PARTICPATING COOLANT

Multiphase Thermal Detonation: MicrointeractionsMultiphase Thermal Detonation: Microinteractions

Propagation Key Physics

ESPROSE.m Verification

Physics Numerics

• Space/Time Discretization

• Numerical Diffusion

• Artificial Viscosity

Analytical

•Exact Solutions for Steady

Detonations (C-J)

•Effect of Idealizations in Exact Solutions

•2D/3D Code Comparison

Integral Aspects

Experimental

• KROTOSAnalytical

• Characteristics Solutions in 1D Geometries

• Exact Solutions in 2D Geometries

Wave Dynamics

• SIGMA

-Single and

Two-Phase

- Multiple regions

Explosion Coupling

Experimental

Analytical

• Characteristics Solutions for Coupled Explosion/Reflection at Free Surfaces

• SIGMA

Constitutive Laws

for Microinteractions

Experimental

rR

H

z

Water Level

Explosion Zone

pSource of radius R

VERIFICATION OF ESPROSE.m CODE

Both DNS and Effective-Field

Ex-Vessel Explosion

EX-VESSEL EXPLOSION

ESPROSE.m Results in the P-v plane

in Relation to Shock Adiabat and the Hugionot

Premixing Key Physics

Penetrative Thermal Radiation

Multifield and Multidimensional

Large Scale Discontinuities

Evolving Melt Length Scales

Eulerian-Lagrangian. No numerical diffusion

Characteristics-Based Matching with MuSiC

Flexibility in “Laws” of Breakup

used to Envelop Premixtures of Risk Significance

PM-ALPHA Verification

Physics Numerics

• Space/Time Discretization

• Numerical Diffusion

Code Comparison

• CHYMES

• PM-ALPHA.3D

Multifield Aspects

Integral Aspects

Experimental

• MIXA

• FARO

Breakup Aspects

Analytical

• Single Particle

• Drift Flux

Experimental

• Single Particle

• MAGICO

• QUEOS

3D Multi-field modeling (4 fields: water, steam, fuel, debris)

Closure laws (flow regimes, boiling heat transfer regimes, momentum transfer, breakup)

VERIFICATION OF PM.ALPHA.L CODE

Representative frames from PM-ALPHA.L simulations Representative frames from PM-ALPHA.L simulations of QUEOS runs Q6, Q8, and Q10of QUEOS runs Q6, Q8, and Q10

Illustration of flow regimes and effect of subcooling as Illustration of flow regimes and effect of subcooling as depicted by PM-ALPHA.L simulations of representative depicted by PM-ALPHA.L simulations of representative

MAGICO runsMAGICO runs

All frames are at 0.3 s following initial contact with water.