MELPROG/TRAC: update and applications

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:7047270

Henninger, R J; Kelly, J E

The first complete, coupled, and mechanistic analysis of a core meltdown sequence has been made with MELPROG-PWR/MOD1 and MELPROG/TRAC. The sequence analyzed was a station blackout accident for the Surry plant. Through vessel failure, all important aspects of the meltdown sequence were calculated. This version of MELPROG permits a full two-dimensional treatment of the in-vessel phenomena. Natural circulation can thus be modeled. Comparison to one-dimensional MELPROG and MARCH calculations shows that natural circulation reduces the rate of core heating, but increases the rate of heating of upper plenum structures and primary piping. This increased heating can inhibit fission product deposition and may lead to an early failure of the primary system. Because of uncertainty, sensitivity studies were performed to assess the relative importance of modeling assumptions. Changes in the modeling of the initial fuel rod melting and relocation were found to vary the hydrogen source by a factor of 2 and alter the timing of key events. These results imply that accurate and mechanistic modeling is important for severe accident sequence analysis.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7047270
• Report Number(s): LA-UR-86-3691; CONF-8610135-31; ON: DE87001984
• Resource Relation: Conference: 14. water reactor safety information meeting, Gaithersburg, MD, USA, 27 Oct 1986; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
MELTDOWN
M CODES
PWR TYPE REACTORS
BLACKOUTS
COMPUTERIZED SIMULATION
CONTAINMENT
FAILURES
HEAT TRANSFER
HYDRAULICS
REACTOR VESSELS
TRANSIENTS
TWO-DIMENSIONAL CALCULATIONS
ACCIDENTS
COMPUTER CODES
CONTAINERS
ENERGY TRANSFER
FLUID MECHANICS
MECHANICS
REACTOR ACCIDENTS
REACTORS
SIMULATION
WATER COOLED REACTORS
WATER MODERATED REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled