Showing papers in "Nuclear Engineering and Design in 1987"

TL;DR: In this paper, two types of models based on a critical ratio of cavity growth or on continuum damage mechanics are presented with constant references to experimental validation studies, and conclusions can be drawn regarding the effectiveness of the methods proposed and their undeniable contribution to fracture mechanics.

TL;DR: In this article, the authors present a local criterion for cleavage fracture based on the critical stress criterion of OROWAN, which can be implemented in computer programs in order to solve much more complex situations where no analytical solutions are available.

TL;DR: In this article, the oxidation kinetics of Zircaloy-4 tubes in steam and hydrogen-steam mixtures and the related changes in the mechanical properties have been investigated.

TL;DR: Continuum Damage Mechanics (CDM) has developed since the initial works of Kachanov and Rabotnov as discussed by the authors, and a review of its main features, of the present possibilities and of further developments is given.

TL;DR: In this article, a prototype system with full computer support for ultrasonic inspection of ferritic tubes using guided waves is described, where ultrasonic waves are launched and received with the aid of electromagnetic acoustic transducers which are layed out as linear phased arrays.

TL;DR: Experimental investigations on the structure of turbulent flow through rod bundles are reviewed in this paper, where the important results of a systematic experimental study of turbolike flow through subchannels of rod bundles were presented.

TL;DR: The EBR-II test program has thus far demonstrated (1) passive removal of decay heat by natural circulation, (2) passive reactor shutdown for a loss of flow without scram, and (3) passive reaction shutdown for loss of heat sink without scram.

TL;DR: A “deep knowledge” approach called Goal Tree-Success Tree model is devised to represent complex dynamic domain knowledge that can hierarchically model the underlying principles of a given process domain (for example nuclear power plant operations domain).

TL;DR: In this paper, three-dimensional flow hydrodynamic distributed resistance models for rod bundles were developed and tested against subchannel velocity and temperature data taken from bundles of triangular rod array configurations with wire-spacers.

TL;DR: The URGAP gap conductance model has been extended and revised generally as mentioned in this paper, and an enlarged data base consisting of approximately 1000 data has been constructed and was used to calibrate the revised UGLAP model.

TL;DR: In this paper, a model was developed to predict the break quality and mass flux and an example was presented to apply the model to steam-water critical branch mass flux through simulated air-water flows through pipe stubs of various diameters.

TL;DR: In this article, a quasi-steady model was proposed to explain the natural circulation phenomena and flowrates in all possible modes of loop natural circulation, and the model can be used to derive simple operating maps that would help the operator identify modes of heat removal during abnormal shutdown conditions.

TL;DR: The Japanese Prototype Fast Breeder Reactor Monju is now at a stage of submitting applications to the government for getting Construction Permission as discussed by the authors, and detailed structural design of components is now in progress.

TL;DR: In this article, the status of development in the modelling of turbulent recirculating flows for the purpose of reactor thermal-hydraulic analysis at the “Laboratoire National d'Hydraulique” is presented.

TL;DR: A series of tests in the Experimental Breeder Reactor No. 2 (EBR-II) have been concluded that investigated the effects of a complete loss of primary flow without scram..

TL;DR: The boundary between small chugging (consisting of low and high frequencies) and condensation oscillation (high frequency only) correlates well with the Hodgson Number to control pulsating gas flow as mentioned in this paper.

TL;DR: In this article, a new methodology for ductile fracture analysis based on the local approach of fracture, through constitutive relations that take into account void growth and damage, has been applied to three heats of A 508 Cl 3 steel with different inclusion contents in the region of 10−3−10−4.

TL;DR: In this article, the authors investigated the concentration of highly-soluble impurities and additives in porous deposits with chimneys, when wick boiling is the major mode of heat transfer, and found that the maximum concentration factor increases with decreasing porosity; increasing chimney population density; increasing system pressure in the range of interest to LWRs.

TL;DR: In this paper, the condition of ductile crack initiation under various stress triaxiality obtained from the tests on axisymmetric notched tensile specimens is well expressed by the conditions of constant void volume fraction analytically obtained from Gurson's model.

TL;DR: In this article, it is shown that CGHF arises in stably stratified parts of the flow if the dissipation of temperature fluctuations is too small to balance source terms for such fluctuations.

TL;DR: In this article, BETA experiments are conducted to investigate the melt-concrete interaction in a large-scale melt facility using internally heated simulated core melts, and the experimental findings are extrapolated to reactor accident conditions by means of computer codes verified experimentally.

TL;DR: A thermal-hydraulics testing and modeling program has been underway at the Experimental Breeder Reactor-II (EBR-II) for 12 years and culminated in two tests of historical importance to commercial nuclear power as mentioned in this paper.

TL;DR: In this paper, a hydro-pneumatic tensile test apparatus was developed which allows dynamic tensile testing at room temperature with and without superimposed ultrasonic oscillations, and the results at low strain rates (10 −3 s −1 ) agree favourably with previous measurements but at high rates (50 s − 1 ) at 20% lower flow stress is observed.

TL;DR: In this article, the inverted annular flow thermal-hydraulics is studied in detail experimentally and a new experimental apparatus has been constructed in which film boiling heat transfer can be established in a transparent test section.

TL;DR: In this article, scaling criteria for a natural circulation loop under single-phase and two-phase flow conditions are derived, and practical applications for designing a scaled-down model are considered, with particular emphasis on scaling a test model at reduced pressure levels compared to a prototype and on fluid-tofluid scaling.

TL;DR: In this paper, a two-fluid formulation for the Inverted Annular Film Boiling region is developed, and the conservation equations, together with appropriate closure relations are solved numerically.

TL;DR: In this paper, the performance of EBR-II has led to performance of whole core transient tests which exceed normal driver fuel operating limits, which demonstrate the inherent safety of both the plant design and the metallic fuel element design.

TL;DR: In this article, two unprotected (i.e., no scram or plant protection system action) loss-of-heat-sink transients were performed on the Experimental Breeder Reactor-II in the Spring of 1986.

TL;DR: The SEFLEX (Fuel Rod Simulator Effects in Flooding Experiments) program is being carried out to quantify the influence of different fuel rod simulators on the thermal-hydraulic behavior during forced feed bottom reflooding of unblocked and blocked arrays.

TL;DR: In this paper, the regulation system for LWRs in Japan is described and some typical points which are attained in the newly developed CCPBR (Construction Code for Prototype Breeder Reactor).