摘要:

Algebraic expressions for the amplitude and phase of the zero power transfer funciton allow these quantities to be evaluated from measured precursor data without the use of a digital computer. The asymptotic forms of the amplitude and phase for large and small values ofωare particularly simple. The expressions show the conditions under which the gain should be frequency-independent and yield a simple formula for the angular frequencyω0at which the phase angle reaches a maximum. The inhour relation is shown to be intimately related to the transfer function, the reactivity in dollars for any periodα−1less than one second being equal to 1−tanε, whereεis the phase angle atω=α. The value ofαcorresponding to prompt critical is shown to be always equal toω0.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15503

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

Thermal neutron spectra have been measured with time-of-flight techniques. Spectra were obtained for pure water and for a nearly homogeneous subcritical assembly where the ratio of thermal absorption to high-energy scattering cross section was∼0.3. For each medium, spectra were measured at 298 and 586°K. The experimental results are presented and compared with calculated theoretical spectra. The agreement between theory and experiment is excellent for the multiplying media. On the basis of this agreement, one concludes that chemical binding effects in light water play a negligible role in determining the equilibrium neutron spectrum in water assemblies.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15504

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

The aim of this paper is to show that the treatment of the transport equation in cylindrical geometry does not involve essentially more tedious calculations than the treatment in plane geometry. A complete solution is given for homogeneous media including the complementary solutions. Every partial solution contains in its expansion of spherical harmonics some functions of a parameter with appropriate coefficients. It will be shown that these functions are Legendre polynomials and Legendre functions of the second kind as in the case of plane geometry for the“main”solution, and derivatives of these functions for the“complementary”solutions. They are solutions of the recursion relations for the expansion and yield a further recursion relation for the coefficients. Tables of these coefficients are given up to the eleventh spherical harmonic approximation and a general formula is derived for them. Two examples are worked out, a first based upon the supposition of a linearly anisotropic scattering law, and a second in which two higher terms of anisotropy are added to this law.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15505

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

Assuming a uniform distribution of ThO2slurry particles suspended in an aqueous medium, the probability of a recoil fission fragment escaping the parent slurry particle and then coming to rest within another slurry particle has been estimated. The results indicate that for the slurry particle diameters and volume concentrations that may be expected in certain homogeneous reactor systems only a small percentage of the fission fragments will end their range within slurry particles. The theoretical predictions compare favorably with experimental results from a U-0 aqueous slurry system.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15506

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

A process for recycling plutonium and uranium alloy fuels is described; it involves melting and liquating the alloys in ceramic crucibles and casting the partially purified metals. Its particular merit is the rapid turnover of a fuel suitable for a fast reactor. A pilot plant, now under construction, will operate in a closed cycle with the EBR-II, and will permit technical and economic evaluation.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15507

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

Six experimental furnaces used for the development of the melt refining process are described. These furnaces permitted uranium or its alloys to be melted without atmospheric contamination while their properties (surface tension, reactions with refractory oxides, decontaminatibility, castability, etc.) were under study.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15508

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

A complex alloy of uranium with zirconium, niobium, molybdenum, ruthenium, and palladium (uranium-fissium) was prepared by induction comelting and casting. Alloying with plutonium and cerium was also studied. Good recoveries of the alloying elements in homogeneous ingots was achieved. The techniques established by this study are being used to prepare the core material for EBR-II.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15509

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

Sessile drops of liquid uranium on five refractory oxide substrates were studied photographically. The volume expansion on melting (ca. 3%), the contact angles (135±3°in each case) and the surface tension of the liquid (826±10% dynes/cm.) were determined. The reactions of liquid uranium with alumina or magnesia proceed stoichiometrically to the expected products. The reactions with zirconia, thoria, and beryllia yield oxygen-deficient substrates and only small amounts of the corresponding metal in solution. The kinetics and reaction mechanism are discussed. Some effects of alloying on these phenomena are also noted.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15510

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

The recovery of metal as cast ingot after melt refining was studied as a function of the size and geometry of the crucible, the time-temperature cycle, the purity of the furnace atmosphere, and the nonmetal impurities present in the charge. The conditions chosen for the pilot plant operation ensure the attainment of the required recovery and recycle of fuel of steady-state composition.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15511

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

A method is described for specifying the transverse leakage (buckling) in each energy group of a multigroup solution of the neutron transport equation. For two dimensional geometry a transverse buckling is associated with one direction and the resulting one-dimensional problem is solved; this gives the first estimate of the energy dependent buckling in the first direction. The next calculation uses this energy dependent buckling as the transverse buckling for a one-dimensional calculation in the other direction. As applied to a completely reflected finite cylindrical core, the method uses the core absorptions and leakages obtained from a one-dimensional multi-group calculation to predict the group bucklings to be used in the next iteration in the other direction. The process is repeated until the buckling in each group in each direction converges. The IBM-704 multigroup diffusion code GNU has been used in conjunction with this buckling iteration method to compute the equivalent spherical radii of a number of fully reflected finite cylindrical cores for which experimental data are available. The equivalent sphere diameters as calculated by the buckling iteration method deviate from the experimental diameters by an average of two per cent over the range of core height to diameter ratios from⅓to 5. The converged value of the multiplication constant was found to be independent of the initial guess made for the axial or radial buckling and insensitive to the transverse bucklings assumed for the regions outside the core for all except very small cores.

ISSN:0029-5639    

DOI:10.13182/NSE59-A15512

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor