Showing papers in "Nuclear Engineering and Design in 1994"

TL;DR: In this paper, a gridless technique called smooth particle hydrodynamics (SPH) has been coupled with the transient dynamics finite element code pronto, and a new weighted residual derivation for the SPH method was presented, and the methods used to embed SPH within pronto were outlined.

TL;DR: Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1991 as mentioned in this paper, Massachusetts State University, Boston, Massachusetts, U.S.

TL;DR: The power-to-volume scaling laws used for the construction of scaled test facilities simulating the primary system of nuclear power plants result in loops of the same elevation (and length) with reduced diameters as mentioned in this paper.

TL;DR: Techniques that include attachment, sliding and automatic generation of particles, which are linked to a standard finite element grid, are described and demonstrated.

TL;DR: In this paper, the average void fraction, bubble size and interfacial area concentration for co-current air-water bubbly flow through a horizontal pipe of 50.3 mm internal diameter were investigated experimentally using the double-sensor resistivity probe method.

TL;DR: In this paper, multidimensional bubbly two-phase flow data was obtained in an isosceles triangular duct having D h = 40 mm and L / D = 73.

TL;DR: In this article, the authors present experimental results on the heat flux distribution at the boundaries of volumetrically heated pools at high enough Rayleigh numbers to be directly relevant to the problem of retention of a molten corium pool inside the lower head of a reactor pressure vessel.

TL;DR: In this article, experimental data are presented that provide a lower envelope on the critical heat flux distribution over the external surface of a hemisphere submerged in water, and the correlation derived from them can be applied directly, and they are supportive of the important, severe accident management idea of retaining the core debris in the reactor vessel by external flooding.

TL;DR: For relatively low ambient flow velocities ( 45 m/s), vapor bubble growth is diminished and high-speed motion of vapor within the bubble leads to an enhanced fragmentation rate as mentioned in this paper.

TL;DR: In this paper, experimental data on volumetric interfacial area in air-water bubbly flow obtained by ultrasonic attenuation are presented and compared with existing correlations, and a new correlation is proposed that applies to upward bubblebly flow in a vertical pipe with natural or forced circulation.

TL;DR: In this article, two important issues are discussed for creep-fatigue evaluation of normalized and tempered modified 9Cr-1Mo (modified 9Cr1Mo(NT)) steel which is a promising structural material for the steam generator of large-scale LMFBRs in Japan.

TL;DR: In this article, the First and Second Order Reliability Methods (FORM and SORM) have been applied in the safety assessment of steam generator tubes with through-wall axial stress corrosion cracks.

TL;DR: In this article, the flow behavior in an open two-phase natural circulation loop was studied experimentally using Freon-113, and three basic circulation modes were observed with variation of the heat flux: periodic circulation, continuous circulation, and periodic circulation.

TL;DR: In this article, the authors used high-speed photography and digital image processing techniques to obtain a database for the development of interfacial transport models, or correlations, for subcooled water-steam flow in vertical conduits.

TL;DR: The approach adopted for severe accident management (SAM) at the Loviisa nuclear power plant (in Finland) is presented and discussed in this article, which includes a number of significant hardware changes and procedures that allow lowering of the lower head thermal insulation and neutron shield assembly, opening of the ice condenser doors, and spraying (externally) of the steel shell of the containment.

TL;DR: In this article, a helically coiled tube (inside diameter, 19.8 mm; coil diameter, 1.17 m; helix angle, 7°27′) with a water-SF6 adiabatic mixture up-flow was measured for total mass flow rates from 500 to 3000 kg s−1 m−2 gas mass fractions.

TL;DR: In this article, the effects of scale and fluid properties on gas entrainment onset were experimentally studied for the free surface flow in an IHX vessel of a proposed Japanese demonstration FBR.

TL;DR: In this paper, the double-sensor resistivity probe technique was applied for measurements of local interfacial parameters, including void fraction, interfacial area concentration, bubble size distributions, bubble passing frequency and bubble interface velocity.

TL;DR: In this article, a statistical formulation is used to describe gas-liquid two-phase flows and a correction factor, the pair correlation function, is introduced to account for dense effects.

TL;DR: In this article, the effects of reduced gravity on the flow regime and the heat transfer characteristics of a boiling two-phase horizontal flow were studied by using an aircraft in parabolic flight experiments.

TL;DR: In this paper, the authors measured void fractions in a simulated PWR core rod bundle geometry under boil-off conditions covering pressures from 3 to 12 MPa and mass fluxes from 5 to 100 kg m −2 s −1, with a particular interest in void fractions at higher pressures and relatively high mass flux.

TL;DR: In this paper, the authors make available the first experimental data on the fragmentation kinetics of hot liquid drops in another liquid (coolant) under the influence of sustained pressure pulses.

TL;DR: In this article, numerical simulations of a passing bubble through sensors are carried out to determine the accuracy of measurement of the interfacial area using electrical resistivity probes, and the results indicated that the two-sensors method is insensitive to the ratio between sensor spacing and bubble diameter, and hitting angle.

TL;DR: Application of the proposed method to the KAIST CHF data bank shows good prediction capability of the CHF, better than other existing methods.

TL;DR: In this paper, integral diffusion theory is used to analyze high temperature Zircaloy oxidation in the flowing steam-H2 environment of a severe fuel damage accident, and the state of the cladding as a function of the time and elevation.

TL;DR: In this paper, the onset of CHF was predicted within an uncertainty of 10% with the KfK correlation using local flow conditions calculated by the subchannel analysis code COBRA-IV-I.

TL;DR: In this article, the authors report results from high temperature tensile and creep tests performed on Inconel 600, 304 stainless steel and SA106B carbon steel, materials used to construct components which penetrate the lower heads of reactor vessels.

TL;DR: In this article, the non-linear dynamics of a two-phase natural circulation boiling channel were investigated by employing the Galerkin nodal approximation method based on the homogeneous flow model.

TL;DR: In this paper, a comparative study of the oxidation behavior of ZrNb1 and Zircaloy-4 was carried out in a steam atmosphere in the temperature range from 700-1100°C.