MELCOR_185_UsersGuide.pdf

NUREG/CR-6119, Vol. 1, Rev. 2 SAND2000-2417/1 MELCOR Computer Code Manuals Vol. 1: Primer and Users’ Guide Version 1.8.5 May 2000 Manuscript Completed: May 2000 Date Published: October 2000 Prepared by R. O. Gauntt, R. K. Cole, C. M. Erickson, R. G. Gido, R. D. Gasser, S. B. Rodriguez, and M. F. Young Sandia National Laboratories Albuquerque, NM 87185-0739 Prepared for Division of Systems Analysis and Regulatory Effectiveness Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 NRC Job Code W6203 NUREG/CR-6119 - ii - Rev 2 Rev 2 - iii - NUREG/CR-6119 Abstract MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor nuclear power plants. MELCOR is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission as a second-generation plant risk assessment tool and the successor to the Source Term Code Package. A broad spectrum of severe accident phenomena in both boiling and pressurized water reactors is treated in MELCOR in a unified framework. These include thermal-hydraulic response in the reactor coolant system, reactor cavity, containment, and confinement buildings; core heatup, degradation, and relocation; core- concrete attack; hydrogen production, transport, and combustion; fission product release and transport behavior. Current uses of MELCOR include estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications. This publication of the MELCOR computer code manuals corresponds to MELCOR 1.8.5, released to users in October 2000. Volume 1 contains a primer that describes MELCOR’s phenomenological scope, organization (by package), and documentation. The remainder of Volume 1 contains the MELCOR User’s Guides, which provide the input instructions and guidelines for each package. Volume 2 contains the MELCOR Reference Manuals, which describe the phenomenologic