摘要:

AbstractAn improved pulsing technique is described that should simplify the experimental procedure in obtaining reliable pulsed data for both theα-measurement and the (kß/) technique. It is shown that an equilibrium pulse shape can be obtained by continuing the time-channel analyzer after the last neutron burst to record all of the neutrons arising from the delayed precursors and providing the recording starts simultaneously with the initial burst. The source strength (neutrons per burst) need not be constant.

ISSN:0029-5639    

DOI:10.13182/NSE64-A18324

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

摘要:

AbstractThe effective resonance integral of thorium oxide rods has been determined as a function of their surface-to-mass ratio. The range ofS/Mvalues covered is 0.15 - 0.65 cm2/g. An experimental technique based on the comparison of activities obtained in thermal and slowing-down neutron fluxes was employed. The shape of the resonance neutron spectrum was determined from measurements with a fast chopper and from calculations, permitting deduction of a correction factor which relates the experimental values to the ideal 1/Ecase. The results are summarized by the following expression:The main contribution to the margin of error arises from the uncertainties in the 4% spectral correction applied, in the 1.5 b“l/v”part deducted and in the 1510binfinite-dilution integral of gold, used as a standard. In order to compare the consistency of Dresner's first equivalence theorem and Nordheim's numerical calculations relative to our results, the resonance integral values for thorium metal rods obtained previously by Hellstrand and Weitman have been recalculated, using recent cross section and spectrum data. The new formula isIt differs from the old one mainly because of the proved non-l/vbehaviour of the thorium cross section below the first resonance.

ISSN:0029-5639    

DOI:10.13182/NSE64-A18325

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

摘要:

AbstractAn exact solution to the energy-dependent Milne problem for isotropic scattering has been obtained using a simple separable scattering kernel. The extrapolation distance and angular distribution at the surface of the half-space have been calculated using the free-gas scattering cross sections. A further calculation for a very narrow kernel shows that the extrapolation distance is insensitive to the inelastic part of the scattering kernel, but depends mainly on the energy dependence of the mean free path. The results have been compared with numerical work obtained from the THERMOS code and thus provide a measure of the accuracy of THERMOS for this type of problem. The results also give physically reasonable bounds on the extrapolation distance and angular distributions.

ISSN:0029-5639    

DOI:10.13182/NSE64-A18326

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

摘要:

AbstractA nonlinear analysis of parameter regions in the“two-temperature”reactor stability problem is accomplished using methods developed in the USSR for treating ordinary differential equations. It is shown that in a model where both temperature-dependent quantities obey Newton's law of cooling, stable limit cycles exist and centers do not exist. If one of the quantities obeys an adiabatic cooling law, centers exist and stable limit cycles do not exist. Solutions with finite escape time are found to exist for certain sets of parameters and initial conditions. Finally, when at least one linear characteristic root vanishes, it is shown that a first integral exists and that it is possible to discuss reactor behavior in terms of this integral.

ISSN:0029-5639    

DOI:10.13182/NSE64-A18327

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18328

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18329

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18330

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18331

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18332

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor

ISSN:0029-5639    

DOI:10.13182/NSE64-A18333

出版商:Taylor&Francis    

年代:1964

数据来源: Taylor