摘要:

AbstractMultiregion critical cores, built on a split-table assembly machine, have been used to investigate reactor compositions typical of epithermal and fast power reactors. The design and operating features of the facility, constructed to study the Th-U233fuel cycle, are described. Criticality calculations have been in good agreement with experimental values.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18786

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractReactivity effects of various materials of interest to epithermal and fast reactors have been measured in a series of neutron spectra with median energies of neutrons causing fission ranging from 422 keV to 8.5 eV. An oscillator technique capable of sensitivities of 10−8Δkwas used. In addition, a power-history or‘reactivity-vs-time’method has been developed for fast but less sensitive reactivity measurements. It has been used to obtain radial reactivity traverses and rod calibrations and for other routine reactivity measurements.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18787

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractSolid-statep-njunction counters have been fabricated to measure fission rates of materials with different fission thresholds. The fission reactions are caused by neutrons varying in energy from thermal energies for U235to 1.5 MeV for Th232. The data gathered from these solid-state fission counters have been used to compare experimental with calculated fission rates in the AETR cores. The fission counter is assembled by placing an electroplated foil of a fissionable material near ap-njunction detector. An aluminum cap is placed over each detector and foil to form a neat, compact assembly. The resulting counter is small enough to fit inside a reactor with minimum distortion to the neutron spectrum. Fission counters employing Th232, U233, U234, U235, U236, U238, Np237, and Pu239as the principal fissionable material have been successfully fabricated. These solid-state fission counters have proved reliable instruments to measure neutron fluxes in high gamma-ray fields. True fission events are easily separated from other induced reactions in the counter.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18788

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractThe variation of neutron importance with energy and position has been investigated in a multiregion critical assembly having a series of test regions typical of slightly epithermal to fast power reactors. Values of neutron importance at the center of the test regions were measured using neutron sources and a reactivity oscillator. The variation of neutron importance with position was determined using neutron sources in conjunction with a dynamic reactivity-measurement technique. Analysis of data from similar beryllium- and carbon-moderated test regions indicates the significance of the Be(n, 2n) reaction. The neutron sources used in this study were Po-Be, Po-B11, Po-CaF2, Po-Li7, Mock Fission and Sb-Be. Published source spectra were used in the analysis of the data; the Mock-Fission-source spectrum was determined by gamma-ray spectroscopy. Relative yields of these sources were determined by calibration in a manganese sulfate bath.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18789

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractIt has been observed that high-velocity coolant flowing through the channels of a parallel-plate fuel assembly will at times cause large deflections of the assembly plates. In the present investigation, hydraulic equations are coupled to the plate equations along the entire length of the assembly. Solution of these coupled equations was accomplished by changing the differential equation developed from plate theory into a non-linear integral equation. The classical method of successive approximations was used to evaluate the integral equation numerically. Numerical results show that: 1) plate deflections take place along the entire length of the plate, and 2) local reductions in channel cross section are further reduced by elastic deflections of the plate.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18790

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractAn analytical method is developed for predicting pressure variations in pressurized steam-surge tanks during liquid insurge. The steam in the tank is considered as a thermodynamic system. The effects on the steam of work done through compression, heat lost through the steam boundaries, and a spray of cold droplets into the steam region are taken into consideration. A solution to the equations employed was obtained by means of an iteration method. Performance curves have been determined with the use of an IBM 650 computer and results compared with those obtained experimentally for a pressurizer operating between 100 and 200 lb/in.2(abs).

ISSN:0029-5639    

DOI:10.13182/NSE65-A18791

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractThe change ink∞of a heterogeneous lattice caused by a uniform change in the temperature of the fuel has been measured, using the Physical Constants Testing Reactor (PCTR). The test lattice was moderated with graphite and fueled with concentric-tube elements of slightly enriched uranium metal. The temperature of the fuel was varied from 297 to 1241°K. The change ink∞with temperature was nonlinear and could be represented by the relationwhereTis in degrees Kelvin. The experimentally measured values of the constants wereα= (−0.308±0.004),β= (−0.120±0.004),γ= (−0.085±0.004). The unit functions, U, represent the changes ink∞caused by the isothermal volume expansion of the fuel element when the uranium metal undergoes transformations in its crystal structure from alpha to beta and from beta to gamma phases. The termCis a normalization factor related to the lattice under study. The reactivity techniques employed here are shown to be four times more sensitive than activation methods for determining the functional relationship between the effective resonance integral of a fuel element and the temperature of the element.The constant,α, has been experimentally separated into two components:αv= (−0.240±0.04). which is associated with the average interior temperature of the fuel, andαs= (−0.068±0.04), which is associated with the temperature of the surface of the fuel. This separation allows treatment of nonuniform temperature distribution in the fuel.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18792

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractBurnout and heat-transfer correlations have been obtained from experimental data in a‘Once-Through Superheat’channel with an exponential heat distribution. Such an electrically heated channel permits local heat fluxes to approach burnout limits in order to maximize total heat input to a test section. Data as a function of the process variables include burnout heat flux in the high quality region and superheat production from 0 to 235°F. The range of the independent process variables are: pressure, 520 to 1900 lb/in.2(gage); flow, 0.0108 to 0.242×106lb/h-ft2, and subcooling from 0 to 327°F. Several comparisons with data in the literature including one for high quality film boiling are made.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18793

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractThe effects of anisotropic scattering approximations in the monoenergetic transport equation are evaluated by calculating discrete eigenvalues, fluxes due to a plane source, and slab critical half-thicknesses, all for homogeneous media. Relative toP2scattering approximation results, which are deemed accurate because of their agreement withP4solutions, the simple transport approximation overestimates eigenvalues and underestimates half-thicknesses in multiplying media while aP1scattering approximation underestimates eigenvalues and overestimates thicknesses, but with smaller error. In the plane source problem, where the detailed flux behavior is observed, the transport approximation is even less accurate; but an extended transport approximation is found to be much more adequate. In overall effectiveness, in order of increasing accuracy, the approximations considered are ranked as follows: 1) transport, 2) forward-backward, 3) first-order Legendre, 4) extended transport, and 5) higher order Legendre. Some evidence is given to indicate that, even for severely anisotropic scattering, relatively low-order Legendre approximations are sufficient to include anisotropic scattering effects.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18794

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor

摘要:

AbstractThe influence of the port void on the thermal-neutron scalar flux at the source plane and on the current at the exit plane of a beam port is examined experimentally and analytically. Activation experiments on 1, 3-, and 5-in. diam ports inserted into the water and graphite reflectors of a swimming-pool reactor are compared with an elementaryP1analysis. The exit current is found to be well-predicted by the theory, which depends only upon a knowledge of the scalar-flux distribution when the beam port is absent.

ISSN:0029-5639    

DOI:10.13182/NSE65-A18795

出版商:Taylor&Francis    

年代:1965

数据来源: Taylor