摘要:

AbstractA study of the extrusion and fabrication characteristics of various titanium-enriched boron dispersions indicate that hot extrusion of uncompacted powders is a feasible method for producing these materials. Tensile and impact properties of dispersions containing 2.43, 3.4, and 3.8 w/o B10show a decrease with increasing B10concentration. Irradiation studies on these materials revealed that internal cracking results after thermal neutron exposures of approximately 4.6×1020nvtand higher. Tensile properties of the dispersions were related directly to the exposure and resulting structure, however, no correlation was found between exposure and impact properties of these materials.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25656

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

Abstract“Blackness theory”is described as a class of procedures for matching a high order transport approximation in one region to a low order approximation in a second region. The matching conditions are presented as a generalization of the Marshak boundary conditions. The blackness coefficients necessary in setting up the conditions are defined and tables are given for slab geometry. A method which allows all regions to be treated by means of the blackness coefficients is developed and applied to two region cells. Numerical results are compared with other approximations in situations typical of those encountered in resonance capture and thermal utilization calculations.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25657

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractThe maximum safe limits on the storage and shipment of slightly enriched fuels may be increased by the addition of fixed neutron poisons. A theoretical study, verified by experiment, is presented to show that an infinite amount of O.95 per cent U235enriched fuel will be subcritical when the fuel elements are encased in tubing at least⅛in. thick. The fuel elements considered are solid rods of 1.34-in. diameter and tubular elements of 1.37-in. O.D. and O.48-in. I.D. Without the tubing it is possible to make as little as four tons of the fuel elements considered critical.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25658

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractThe multigroup diffusion equations are solved formally by expanding the flux in each group in a series of eigenfunctions of the scalar Helmholtz equation. The resulting secular determinant is complicated, but a perturbation solution may be developed for the coupled multigroup equations. In the case of one energy group, the perturbation method chosen reduces to a formula simpler to use and more rapidly convergent than the Rayleigh-Schroedinger formulas. An operator convenient for expressing the boundary conditions at an interface in multiregion reactors is defined. The foregoing techniques are applied to the Fermi age equation for a reflected reactor. Numerical examples are given to illustrate the rates of convergence in typical reactor design problems.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25659

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractA quantitative but simple theory of the control effect of a uniformly distributed set of thermal poison elements in a hydrogen-moderated bare reactor core has been developed. Starting with plane parallel poison sheets, a zero-flux boundary condition, in a slab core and applying Fourier analysis, it has been possible to generalize to any boundary condition, to orthogonally intersecting sets of poison sheets in an infinite rectangular core, to control crosses, and cylindrical rods in regular array, to finite rectangular cores, and to finite cylindrical cores. Each element of the control array is associated with a cross-sectional areaAcwithin the core and within this area is an easily determined effective“absorption area”C. To a rather good accuracy the criticalkof the controlled core is greater than thekof the uncontrolled core by the ratioAc/(Ac−C). In this the theoretically based conclusion substantiates the intuitionally based and empirically confirmed methods worked out by Greebler (1), and by Pearlstein, Ruane, and Storm (2), and furnishes correction terms.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25660

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractThis paper presents the results of an experimental study of the elastic response of four geometrically scaled models of nuclear reactor outer containment shells to internal blast loading. The character of response of the shells to dynamic loading is determined with the shells unsupported (suspended in air) and with the shells half-buried in the ground. Geometrical modeling of the response is verified for both support conditions.The results of a static pressure test of one vessel show that dynamic response cannot be inferred from static considerations.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25661

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractHardness, density, and thermal expansion data are presented for alloys of uranium with certain fission-product elements. The elements are those expected to remain in a spent fuel from a fast reactor following pyrometallurgical refining. In cast and gamma quenched alloys the retention of the high-temperature gamma phase produces low hardness and low density. Thermal expansion behavior is dependent upon composition and prior thermal history.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25662

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractThe problem of designing a reactor with minimum total mass is posed. This problem is related to that of designing a reactor with minimum critical mass. For a simple class of thermal slab reactors, the known solution of the minimum critical mass problem enables a complete solution of the minimum total mass problem.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25663

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractTheoretical and experimental results of the time behavior of neutron density as a function of both positive and negative step changes in reactivity are presented. The theoretical results are obtained from solutions of the space-independent kinetic equations of a bare thermal reactor based on the Fermi continuous slowing down model and using six groups of delayed neutrons. Theoretical results are given as a function of both positive and negative step changes in reactivity. Experimental results of reactivity worth and of rod calibrations based on pedagogical experiments with the Argonaut Reactor and verifying the theoretical data are presented together with the details of the pedagogical experiment. An analytically constructed thermal flux function obtained from results of reactivity measurements in the reactor is compared with the actual recorded flux from the reactor. Experimental results obtained with the Argonaut Reactor indicate that the theoretical kinetic behavior predicted in this paper are applicable to the actual Argonaut Reactor.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25664

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor

摘要:

AbstractA loss-of-coolant accident in a pressurized water, nuclear power plant is one which permits coolant to escape from the primary system. If such an accident were allowed to proceed uninhibited by corrective measures, the core may lose sufficient coolant such as to permit core heatup. In order to design a system to maintain the core cool, it is necessary to evaluate the coolant blowdown process which occurs after rupture and thereby establish the pressure-time and volume-time relationships of the primary coolant after rupture.The coolant blowdown process after rupture is complex because the two-phase expansion of water and steam obtains after saturation pressure is attained. The analysis of this process utilizes heat, mass and volume balances of the reactor coolant to establish the thermodynamic state of the reactor coolant at any time after rupture within conservative limits.

ISSN:0029-5639    

DOI:10.13182/NSE59-A25665

出版商:Taylor&Francis    

年代:1959

数据来源: Taylor