Natural convection model of molten pool penetration into a melting miscible substrate
- Fauske Associates Inc., Burr Ridge, IL (United States)
Studies of postulated severe accidents in nuclear reactors have involved consideration of the extent of core-debris-melt penetration into the lighter and miscible concrete substrate below the reactor vessel. It is suggested in this paper that the melting of concrete by an overlying pool of oxidic core material/concrete mixture is partially driven by classical liquid-turbulent natural convection, with plumes of molten concrete providing the required strong mixing conditions. Experiments have shown that the melting of a solid by a heavier overlying hot pool miscible with the solid material in the absence of gas bubbling is a boundary-layer phenomenon involving the steady generation of narrow columns or streamers of melt material from a stable melt layer that exists between the melting solid and an overlying pool. The streamers originate at discrete sites at the melt layer/pool interface and continuously inject melt material into the overlying pool. It is reasonable to assume that streamers of molten concrete are present near the bottom of the overlying oxidic core material pool. It can be demonstrated with the analysis described in the next paragraph that the streamers rather than gas bubbles are chiefly responsible for concrete slag removal and mixing with the oxidic pool and are capable of producing a level of thermal convection within the oxidic pool that is comparable to that produced by gas bubbling. This important phenomenon has not been considered in the available models of molten-core debris/concrete heat transfer.
- OSTI ID:
- 6844282
- Report Number(s):
- CONF-931160-; CODEN: TANSAO
- Journal Information:
- Transactions of the American Nuclear Society; (United States), Vol. 69; Conference: American Nuclear Society (ANS) winter meeting, San Francisco, CA (United States), 14-18 Nov 1993; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Natural convection characteristics of pool penetration into a melting miscible substrate. Final report
Growth of molten core debris pools in concrete. Part II. A. Pool growth in composite beds; B. Effect of overlaying steel layers. Final report, March 1, 1978-September 30, 1979. [LMFBR]
Related Subjects
CONCRETES
MELTING
POWER REACTORS
REACTOR CORE DISRUPTION
CORIUM
HEAT TRANSFER
MATHEMATICAL MODELS
NATURAL CONVECTION
ACCIDENTS
BUILDING MATERIALS
CONVECTION
ENERGY TRANSFER
MASS TRANSFER
MATERIALS
PHASE TRANSFORMATIONS
REACTOR ACCIDENTS
REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety