摘要:

AbstractThis paper deals with a design optimization system for a fast reactor. The system consists of a nonlinear programming code and the usual design codes. If proper design criteria and an initial estimate of a design point are provided, the optimum design point, subject to those criteria, can be automatically obtained by the system. The system was successfully applied to the optimization and sensitivity analysis of a typical large fast reactor. The results show both the features of the optimized reactor and the effects of variations in the main design criteria on the design.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23252

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractThe control of spatial xenon-induced oscillations in large power reactors is considered from the point of view of practical operator manual control. A control strategy is developed based on control theory concepts and considerations of the physics of the problem. It is shown that oscillations can be eliminated by a simple control action consisting of positioning a control rod in a specified location for a specified length of time; upon retrieval of the control rod to its equilibrium position, the flux, xenon and iodine distributions will have returned to equilibrium conditions. A control equation is derived from which the control rod insertion time and the duration of control can be calculated. For large pressurized water reactors of current and anticipated designs, control rod insertion times are in the range from one to four hours before the peak in the oscillation, while control times vary from one-half to two hours. Digital diffusion theory simulations are described which tend to verify the control concepts developed in the paper. Constraints in local power peaking are introduced by considering control at off-optimal times. The study provides guidelines for operator control which is near optimal in the sense that control actions are minimized in number and are most effective in terms of eliminating the oscillation.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23253

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractLow resolution transmission experiments on 14- and 20-in.-thick samples of iron have been conducted at Rensselaer Polytechnic Institute’s linear accelerator to evaluate the adequacy of various data files in predicting total neutron cross-section minima from 24 to 750 keV. From our transmission area analysis we conclude that both the Penny-Kinney file and Version-19 file (incorporating the Columbia minima measurement) generally overestimate the total cross section in the region of minima, with the Version-19 file strongly preferred for accurate minima prediction. With the ENDF/B-III (MAT 1180) file identical to the Penny-Kinney file (except about the 24-keV minima), similar negative conclusions apply. At approximately the 24-keV minima where our resolution is sufficient to evaluateθt(E), we obtain excellent agreement with ENDF/B-III (MAT 1180). We quote (σt)min = 0.42±0.03 b atE= 24.3±0.1 keV.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23254

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractEnergy spectra resulting from the scattering of gamma rays under various conditions were calculated by a Monte Carlo method. As a result of systematic studies on the low energy components of the spectra, it was found that they were not affected very much by source energy or scatterer geometry but were affected by the atomic number of the scatterer. These properties could be explained successfully by a relatively simple theory including the continuous slowing down approximation. A formula expressing the relationship between the position of the peak appearing in the low energy region of the spectrum and the atomic number of the scatterer was derived from the above calculations and the theory.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23255

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractAn analytical study was performed to investigate the utility and accuracy of the lumped parameter approach to heat transfer analysis in a nuclear reactor subassembly. It is shown that the lumped parameter approach is a useful mathematical method if the appropriate heat transfer length scales associated with diffusion heat transfer are employed. Important results of this study supporting the utility of the lumped parameter approach indicate that in the parameter range of interest the length scales are geometry-dependent only. They are shown to be independent of radial power distribution across the subassembly, and asymptotic values which are equal to length scales corresponding to the thermally fully developed condition may be used in the thermally developing entry region which encompasses the entire axial length of typical nuclear reactor subassemblies. Two characteristic length scales are presented and may be easily applied in lumped parameter steady-state heat transfer calculations in spacer-free triangular arrays of nuclear fuel elements within the range of parameters of interest for nuclear reactor applications. These length scales apply to fuel rods adjacent and nonadjacent to subassembly walls, respectively.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23256

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractA high-pressure3He proportional counter has been developed with good energy resolution for fast neutrons, and detailed descriptions are given of its construction and calibration and the determination of its response function. The spectrometer was used to measure the delayed-neutron energy distribution for samples of232Th,233U,235U,238U, and239Pu repetitively irradiated in the Israel Research Reactor-1. Irradiation and counting times were optimized to accentuate group 2 and group 4 delayed neutrons. Corrections were applied for the finite energy resolution, for the energy-dependent detection efficiency and for spectrum distortion due to gamma rays. An approximate energy spectrum was obtained for group-1 delayed neutrons, and more precise spectra were obtained for group-2 delayed neutrons from each of the samples investigated. Preliminary results are also given for group-4 delayed neutrons from232Th and235U.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23257

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractAn investigation is made of a new approach to solving the multimode kinetics equations. These equations are cast into a matrix generalization,of the point kinetics equations and successfully solved by applying an analytic inversion of the matrix [[I] -∊[A]] to both the Padé(2,0) and modified Padé(1,1) approximations to exp(Δt[A]).

ISSN:0029-5639    

DOI:10.13182/NSE73-A23258

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractA general multidirectional modal representation for the angular density of the one-speed neutron transport equation is discussed. The properties of orthogonality and recurrence are presented together with expressions for several neutranic parameters. The system of equations for the spatial moments are established and certain features described. It is shown that some known solution formulations are special cases of this more general representation.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23259

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractThe monoenergetic integral transport equation is solved in an approximate manner by separating the integral into an asymptotic component plus a transient boundary component. Solutions to the resulting equation are obtained with only a modest increase in complexity over diffusion theory. The method is illustrated by several examples in which significant improvement over diffusion theory is obtained.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23261

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor

摘要:

AbstractRecent measurements of the neutron yield resulting from the alpha-particle bombardment of carbon have disclosed an error in the data reported in the literature. New values of the thick-target yield of neutrons are ~20% of the previously reported values for alpha-particle energies between 2 and 5.3 MeV and ~10% between 5.3 and 9.0 MeV.

ISSN:0029-5639    

DOI:10.13182/NSE73-A23262

出版商:Taylor&Francis    

年代:1973

数据来源: Taylor