Threshold for sweepout from pedestal region of Mark III containment. [BWR]

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6339017

Sienicki, J J; Spencer, B W

The assessment of the consequences of highly unlikely severe accident sequences in boiling water reactors includes those sequences in which molten corium is postulated to meltthrough the reactor pressure vessel (RPV) lower head and enter the pedestal region beneath the vessel. If localized melt-through of the reactor vessel occurs at elevated primary system pressure, the ejection of molten corium from the vessel will be followed by a blowdown of steam and hydrogen. The gases flowing from the breached vessel constitute a source of driving forces capable of dispersing corium from the pedestal into other parts of the containment. The extent of the gas blowdown-driven sweepout process depends upon a number of factors including the primary system pressure at melt through, breach flow area, overall blowdown timescale, and the specific pedestal/containment geometry. A model is presented to predict whether or not the conditions of gas flow from the failed RPV are sufficient to cause sweepout of corium and/or water from the pedestal. The model is shown to predict the onset of sweepout in scale model, simulant material experiments and is applied to the investigation of sweepout in the full-size reactor system.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6339017
• Report Number(s): CONF-841105-18; ON: DE84014755
• Country of Publication: United States
• Language: English

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