SCDAP/RELAP5 Modeling of Movement of Melted Material Through Porous Debris in Lower Head

Technical Report · Tue Dec 01 00:00:00 EST 1998

DOI:https://doi.org/10.2172/5864· OSTI ID:5864

Siefken, L J

Designs are described for implementing models for calculating the movement of melted material through the interstices in a matrix of porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and nonporous debris that results from core material slumping into the lower head during a severe accident in a Light Water Reactor. Currently, the COUPLE model has no capability to model the movement of material that melts within a matrix of porous material. The COUPLE model also does not have the capability to model the movement of liquefied core plate material that slumps onto a porous debris bed in the lower head. In order to advance beyond the assumption the liquefied material always remains stationary, designs are developed for calculations of the movement of liquefied material through the interstices in a matrix of porous material. Correlations are identified for calculating the permeability of the porous debris and for calculating the rate of flow of liquefied material through the interstices in the debris bed. Correlations are also identified for calculating the relocation of solid debris that has a large amount of cavities due to the flowing away of melted material. Equations are defined for calculating the effect on the temperature distribution in the debris bed of heat transported by moving material and for changes in effective thermal conductivity and heat capacity due to the movement of material. The implementation of these models is expected to improve the calculation of the material distribution and temperature distribution of debris in the lower head for cases in which the debris is porous and liquefied material is present within the porous debris.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC07-94ID13223
• OSTI ID: 5864
• Report Number(s): INEEL/EXT-98-01178; TRN: US0101693
• Resource Relation: Other Information: PBD: 1 Dec 1998
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
S CODES
R CODES
POROUS MATERIALS
REACTOR VESSELS
SPECIFIC HEAT
TEMPERATURE DISTRIBUTION
THERMAL CONDUCTIVITY
MASS TRANSFER
WATER COOLED REACTORS
C CODES
CORIUM
INTERSTICES
POROUS DEBRIS
LOWER HEAD
REACTOR VESSEL
COUPLE
SCDAP/RELAP5
NONPOROUS DEBRIS
CORE MATERIAL
SEVERE ACCIDENT
LIGHT WATER REACTOR
EFFECTIVE THERMAL CONDUCTIVITY
MELTED CORE MATERIAL