CONTRIBUTION TO THE THEORY OF TWO-PHASE, ONE-COMPONENT CRITICAL FLOW

Equipment was built where critical-flow data above 100 psia were obtained and a theory developed that predicts the experimental values satisfactorily. Theoretical expressions for the specific volume, void fraction, and slip ratio for critical steam-water mixtures have been derived. Therefore, the first complete analytical solution was made possible for estimating the critical two-phase flow rate, including slip between the two phases. The pressure profiles for runs at critical flow were all characterized by extremely steep pressure gradients near the throat; however, the pressure gradients are definitely finite and approach absolute maximum values, these depending only upon critical flow rate and quality. Sonic velocities are not achieved in critical two-phase flow of steam--water mixtures. Therefore, the phenomenon of two-phase critical flow differs significantly from that of single-phase critical flow. A new theory has been postulated in an effort to explain the mechanism of two-phase critical flow. The geometry of the system to be investigated has apparently no effect on the critical-flow phenomenon for the diameters and lengths of pipes used in this work. The experimental data obtained compare favorably with previous investigations in the range of variables where such a comparison is possible. The Homogeneous Flow Model'' is found to be unsatisfactory for all critical throat pressures and qualities examined. The assumption of no slip between the phases, therefore, can be said to be definitely incorrect. Since the theory presented describes the critical phenomenon satisfactorily for all pressures and qualities examined so far, and no parameters depending on experimental values are needed, the theory is believed to be highly valuable in determining the maximum discharge of steam--water mixtures from conduits and breaks'' in vessels and pipes. The applications are subjects of considerable concern in the evaluation of nuclear reactor accidents and containmen among others. (auth

Liquid metal fast breeder reactor safety: an overview including implications of alternate fuel cycles

Key issues concerning LMFBR safety are reviewed. A brief discussion of alternate fuel cycles for preventing diversion of fissionable materials is included

Mechanism of liquid--liquid contact and heat transfer related to fuel- coolant interactions

BS>From second specialist meeting on sodium fuel interaction in fast reactors; Ispra-- Varese, Italy (21 Nov 1973). The requirements for explosive boiling (vapor explosion) are discussed with special emphasis on the UO/sub 2/-Na system. Considerations include requirements for direct liquid-liquid contact and associated heat transfer characteristics. Fragmentation and explosive boiling are treated as separate phenomena. (auth

Westinghouse independent safety review of Savannah River production reactors

Westinghouse Electric Corporation has performed a safety assessment of the Savannah River production reactors (K,L, and P) as requested by the US Department of Energy. This assessment was performed between November 1, 1988, and April 1, 1989, under the transition contract for the Westinghouse Savannah River Company's preparations to succeed E.I. du Pont de Nemours Company as the US Department of Energy contractor for the Savannah River Project. The reviewers were drawn from several Westinghouse nuclear energy organizations, embody a combination of commercial and government reactor experience, and have backgrounds covering the range of technologies relevant to assessing nuclear safety. The report presents the rationale from which the overall judgment was drawn and the basis for the committee's opinion on the phased restart strategy proposed by E.I. du Pont de Nemours Company, Westinghouse, and the US Department of Energy-Savannah River. The committee concluded that it could recommend restart of one reactor at partial power upon completion of a list of recommended upgrades both to systems and their supporting analyses and after demonstration that the organization had assimilated the massive changes it will have undergone