摘要:

AbstractThe effects of H2O contamination on lattices of natural uranium metal in D2O were measured in the exponential facility of the Savannah River Laboratory. The buckling changes associated with H2O contamination were determined for two lattices with moderator-to-fuel volume ratios of 12.3 and 14.6 over a range of H2O concentrations from 0.2 to 8.2 mol %. The agreement between calculated and experimental changes in buckling for these lattices was within±25×10−6cm−2. Similar measurements on seven other lattices with moderator-to-fuel ratios in the range from 31 to 212 were made for a change in the H2O concentration from 0.18 to 3.92 mol %. For these measurements the experimental change in buckling was about 15% greater than the calculated change.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29076

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractThe thermal stresses in the nozzles of heavy-walled reactor vessels, caused by sudden changes in coolant temperature, are of great interest to the reactor designer. An analysis has been made of this problem for both high and low flows of cold water. The results show that the nozzle investigated can endure a large number of cycles of the worst case analyzed.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29077

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractThe neutron balance of a reactor system is probably the most important single quantity to be obtained from an analysis of static core physics. In a heterogeneous reactor configuration, an accurate knowledge of the different reaction rates must be obtained by first studying the unit cell. The results for the unit cell are used in the homogenization of the reactor lattice so that a multigroup, multiregion reactor program may be used to investigate the reactions rates of the reactor system. A study was made of the ability of theSnform of the neutron Transport Equation to describe accurately the thermal neutron flux distribution in a unit cell. The uncertainties introduced into the problem by spectrum hardening in heterogeneous cells were minimized by confining most of the comparison of theory with experiment to natural uranium rods in diphenyl and D2O. A slightly enriched uranium slab in a water lattice was used for comparisons of results published in reference (1). Results are evaluated on the basis of theSnmethod's ability adequately to calculate the spatial variation of the thermal flux distribution when compared with experiment. Excellent agreement was obtained for theSncalculations.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29078

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractUranium carbide containing about 5.2 w/o carbon has been irradiated to nominal burnups of 1000 and 5000 Mwd/ton of carbide. The results are generally encouraging, although some cracking has been observed. The observed density decreases were about the same at 1000 and 5000 Mwd/ton irradiations, being 0.7 to 2.5 and 0.6 to 2.5% respectively. The problems and questions raised by these irradiations are discussed. Additional irradiations are planned to study the effects of composition and of burnups to 15,000 Mwd/ton of carbide.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29079

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractThe operational and conceptual significance of the reactor kinetics parameters is considered, with especial reference to the generation time, the reciprocal production probability. The kinetics equations are given in a form parametric in the generation time, a form which is usually more accurate and always simpler to solve than the corresponding form in the lifetime, the reciprocal destruction probability. Typical solutions are given for several simple and more sophisticated problems employing a further useful set of nondimensional parameters.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29080

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractIt has been observed in the past that the computer time required for the numerical solution of the transport equation has been almost prohibitive for many problems of interest. Results of a study designed to improve the convergence rate of the angular segmentation orSnmethod are presented. Examples showing the effect of several different modifications of the standardSnmethod are given. It is recommended that the incorporation of the modification discussed will significantly improve the convergence of theSnmethod and permit an efficient solution of many problems related to thermal assemblies.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29081

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractOne of the pressing problems of the potential nuclear-power industry is the necessity for disposing of radioactive wastes incident to operating reactors and recovering fissionable material from expended fuel elements. The Bureau of Mines has made a detailed analysis of the feasibility of solving this problem in areas where the geology permits by injecting liquid wastes into shallow, permeable, sedimentary rock formations. General considerations pertinent to the disposal of radioactive wastes are reviewed. Suggested methods of disposal, geographical influences, and the factors pertaining to shipping liquid and solid radioactive wastes are discussed. Current practices of the oil industry in the United States in disposing of oil-field brines are reviewed. The economics of brine injection is compared to present costs of storing and estimated costs of disposing of high-level radioactive wastes. A comparison is made of the current costs of drilling wells to different depths; the relative economics of drilling exploratory, injection, and monitoring wells to different depths in a disposal or test project is discussed. The geology of comparatively shallow and stratigraphically isolated sandstone lenses and shoestrings common to midcontinental United States is considered. Particular emphasis is given to the geological, engineering, and chemical information available about such formations that have been proved to be productive of petroleum and have been repressured with fluids to stimulate oil production. Laboratory and field research problems pertinent to the disposal of radioactive wastes by injection are outlined. Laboratory problems include ion exchange and adsorption of fission products, chemical and physical reactions between injected wastes and reservoir solids and fluids, corrosivity of wastes and corrosion resistance of special metallic alloys, injectivity of solutions of waste fission products, potential heat gradients, and techniques for determining migration of injected wastes. Field research problems include handling techniques, injectivity, and horizontal and vertical migration of injected radioactive wastes. A hypothetical example is given of a pilot plant for secondary treatment and injection of dilute fission products into a shallow, lenticular sandstone formation with well-defined boundary conditions. Monitoring facilities and techniques designed to determine horizontal and vertical migration and differentiation of the migrating radioisotopes are described. A partial cost analysis is made of the pilot system. The advantages and disadvantages of a full-scale system of this type, as compared with other methods of disposal are discussed. It is concluded that the use of shallow sedimentary formations, including partly depleted oil-productive sands, for disposing of radioactive wastes in some areas where geology permits, is feasible and that field pilot plants to demonstrate that feasibility might be instituted with information available at this time.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29082

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractThe Greuling-Goertzel approximation is applied to the calculation of neutron slowing down in heavy water in theB1andP1approximations. Numerical calculations of the flux and nonescape probability assuming constant cross sections indicate the“inconsistent”G-G B1approximation to be the most favorable. Existing machine codes can readily be modified to this method.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29083

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractA Boron-lined proportional counter has been developed whose cathode diameter varies continuously, hence varying the gas multiplication along the length of the counter. The sensitive area of the cathode thus becomes a function of the applied voltage, electrical amplification, and pulse-height discrimination. A semi-empirical relationship between counter geometry, gas parameters, and applied voltage is used to develop theoretical expressions for the dependence of count rate on applied voltage and cathode geometry. The behavior of cathodes of hyperbolic and exponential shape is treated. A prototype exponential counter, operated in a pulse counting mode, was constructed and tested. The approximately logarithmic relationship between neutron flux and voltage predicted for such an instrument was confirmed.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29084

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor

摘要:

AbstractIt is conventional practice in the design of nuclear reactors to introduce hot channel factors to allow for spatial variations of power generation and flow distribution and for manufacturing tolerances. The factors are presently considered to be cumulative; the over-all hot channel factor at a point in the reactor is the product of all the factors applicable at the point. This paper demonstrates a more exact method of determining and interpreting the combined as well as individual hot channel factors through the use of statistical methods.

ISSN:0029-5639    

DOI:10.13182/NSE60-A29085

出版商:Taylor&Francis    

年代:1960

数据来源: Taylor