Assessment of the reflood oxidation models in SCDAP/RELAP5/MOD3.1

Conference · Mon Apr 01 04:00:00 EST 1996

OSTI ID:245071

Hohorst, J K; Allison, C M

Reflooding of a hot damaged core following the start of a severe accident can lead to significant increases in the heating, melting, and oxidation of the core prior to the termination of the accident. These effects have been observed in bundle heating and melting experiments terminated by the addition of water and are postulated to have had a major impact on the accident progression in the TMI-2 accident. Although the detailed mechanisms for the processes are not completely understood, new SCDAP/RELAP5/MOD3.1e models, describing the cracking /spalling of oxidized fuel rod cladding during reflood, and the resulting oxidation of the underlying Zircaloy and relocating liquefied U-Zr-O, provide a reasonable estimate of the experimentally-observed bundle temperatures, hydrogen production, and changes in bundle geometry. This paper provides a brief description of the new models, selected highlights from code-to-data comparisons, and selected results from a recent set of calculations fro TMI-2 using the new models. The potential impact of these new models on other plant calculations is discussed in the concluding portion of this paper.

• Research Organization: Idaho National Engineering Lab., Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC07-94ID13223
• OSTI ID: 245071
• Report Number(s): INEL--96/00094; CONF-9603159--1; ON: DE96009019
• Country of Publication: United States
• Language: English

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