摘要:

AbstractMolten glass interacts explosively with water under certain contact mode conditions. The contact mode found explosive is as follows: Molten glass enters the water bath in the film boiling regime (as predicted by Dhir's correlation), and soon after entry the vapor film is perturbed sufficiently by an external pressure pulse. The ensuing reaction proceeds basically along the same lines as energetic tin/water interactions observed by several investigators. In the absence of this pressure pulse, the event is nonenergetic.The present findings are for a combination in which the hot material has a very low thermal diffusivity and the calculated interface temperature is significantly (∼180 K) below its melting temperature. This is similar to the characteristics of the UO2/sodium or UO2/water combinations. The observed explosive glass/water interactions show growth times on the order of a few milliseconds. The particulate size distribution from the present tests was coarser than the particulate size distribution from some in-pile and out-of-pile UO2/sodium interaction tests.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27197

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractThe establishment of nuclear fuel requirements and their efficient utilization requires a detailed knowledge of some aspects of fuel dynamics and processing during the reactor lifetime. It is shown here that the use of the fuel stockpile inventory concept can serve effectively for this fuel management purpose. The temporal variation of the fissile fuel doubling time as well as non equilibrium core conditions are among the characteristics which thus become more evident. These characteristics—rather than a single figure-of-merit—clearly provide an improved description of the expansion capacity and/or fuel requirements of a nuclear reactor energy system.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27198

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractFor the requirement of feasibility studies of the (11B +1H) controlled thermonuclear reactor system, the11B(α,p0)14C reaction has been studied with alpha particles of energies ranging from 4.4 to 6.7 MeV. Absolute differential cross sections were measured. Angular distributions and excitation functions are presented. The absolute error in the measured total cross sections is∼13%.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27199

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractEffects of fine-structure fluctuations in the importance function spectrum on the accuracy of the reactivity-reaction-rate (RRR) method for the determination of the effective capture-to-fission ratio () are investigated using a simple single-resonance model. It is found that multigroup calculations with flux-averaged group constants do not adequately take these effects into account. This can impair the accuracy of the value ofdetermined by the RRR method. A prescription for accurately taking the fine-structure spectral effects into account is given.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27200

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractThe fission cross-section ratios of233U to235U and239Pu to235U were measured over the neutron energy range from 1 keV to 30 MeV at the Lawrence Livermore Laboratory 100-MeV Linac. Ionization fission chambers and the time-of-flight technique were used to take data simultaneously over the entire energy range. This provided accurate determinations of the shape versus neutron energy of the ratios. Two independent methods were used to determine the average value of each ratio in the interval from 1.75 to 4.0 MeV for the purpose of normalization. Over the 1-keV to 30-MeV range, the total uncertainties for the233U-to-235U data range from 2 to 4%; the239Pu-to-235U data uncertainties range from 1 to 4%.

ISSN:0029-5639    

DOI:10.13182/NSE78-1

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractCapture and scattering probabilities for neutrons impinging on thick samples were measured by the Japan Atomic Energy Research Institute Linac time-of-flight spectrometer and were compared with those by Monte Carlo calculation. Sweeping the incident neutron energy, the capture probability shows peaks at resonance energies in the case of a thin sample, whereas it shows dips for a thick sample, i.e., saturation occurs just at resonance energies. This saturation phenomenon is analyzed by Monte Carlo calculation for a distribution of path lengths of incident neutrons in the sample until capture in the sample. The saturation values of capture probability at resonance energies Pcoare defined, and their dependence on the resonance parametersΓn/Γis examined. The relations between PcoandΓn/Γ, with parameters including recoil energy, are obtained by Monte Carlo calculation. The relations are verified by measurement of Pcofor many resonances of variousΓn/Γvalues. With the relation,Γn/Γcan be determined from Pco, which is not sensitive to sample thickness.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27202

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractThe expression for the source importance factor is derived in the frame of the adiabatic approximation. This factor plays an important role in the point kinetic equations when extraneous sources are present. It is shown how to get a very accurate value using standard codes that solve the steady-state transport (or diffusion) equation, but not the adjoint problem. Several numerical examples are discussed.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27203

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractA method of solving reactor kinetics equations by using third-order Hermite polynomials for the approximation of neutron density (or power density) and delayed group precursors in finite time intervals is presented. When the reactivity is given, including the case of the feedback reactivity being a function of neutron density, this method can provide a straightforward procedure for computing reactor dynamics problems.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27204

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractIn a spherical lithium metal assembly with a graphite reflector, the changes in the fission rates of235U and238U due to changes in the cross-section sets of the constituent elements of the assembly are calculated. The results are discussed on the basis of experimental data. The fission rate of235U is found to be most sensitive to changes in the cross-section set of6Li in the lithium region, while in the graphite reflector, it is most sensitive to that of12C. The fission rate of238U is found to be more sensitive to changes in the cross-section sets of the elements in the stainless-steel structure rather than to those of lithium or graphite.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27205

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor

摘要:

AbstractThe concepts of decay-width-pooled distributions and of effective number of degrees of freedom have proven helpful in the calculation of inelastic scattering cross sections and emitted particle spectra, where channels leading to the excitation of bands of levels in the continuum are open at energies low enough for the width fluctuation effects to remain sizable.

ISSN:0029-5639    

DOI:10.13182/NSE78-A27206

出版商:Taylor&Francis    

年代:1978

数据来源: Taylor