摘要:

AbstractThe cost of control rods which contributes a significant fraction to the total cost of a power reactor core is discussed as a function of metallurgical composition and reactor endurance. Materials considered include hafnium, Cd5-In 15-Ag80 alloy, several boron carrying systems, and dispersions of such rare earth oxides as Eu2O3, Gd2O3, and Dy2O3. Costs based on a thorough analysis of processing variables and raw material prices are presented for a variety of rods for a specific reactor design considered typical of enriched power plants of the present generation. Concentrations were established by an approximate method described by Stevens. Although this method is relatively crude, results are considered adequate for purposes of this paper. For long-lived cores the lowest cost rods of proven composition were a composite rod with hafnium tip and boron dispersion upper blade or hafnium rods if the hafnium can be bought at presently quoted zirconium co-product prices. Rare earth cermets of properly adjusted composition also fell into an interesting price range. Boron dispersions though lower in cost cannot be considered among the proven materials for long-lived high burn-up cores. For shut down rods or cores of shorter endurance boron steels offer a low cost solution to the problem. For cores of intermediate endurance or shut down rods for longer endurance cores, Cd-In-Ag alloy rods may be of use and are certainly economically attractive.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25858

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe four-factor critical equation for a heterogeneous thermal reactor is looked at in detail. It is then written in terms of parameters which characterize separately the fuel element, the moderator, and the lattice cell geometry of a heterogeneous thermal reactor. Methods for determining the parameters are then discussed. The results of measurements and analysis for two different fuel element types are compared with the results of measurements made on full lattices consisting of these fuel elements.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25859

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractFour methods are discussed for predicting the change of static pressure across an abrupt expansion for the flow of liquid vapor mixtures. Design equations are given and recommendations are made for boiling reactor calculations.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25860

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe partition of plutonium between liquid magnesium and liquid uranium or uranium-chromium alloy was investigated. The extraction was found to be reversible and essentially independent of concentration up to one weight per cent plutonium. The molar partition coefficients for both systems can be expressed as a function of temperature by the equation logK= 1887/T−2.010.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25861

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe validity of using the homogenization approximation in a lattice end-leakage calculation was studied in a series of Monte Carlo scattering order analysis experiments. A method for using the homogenization approximation in Monte Carlo end-leakage calculations is described. The analysis indicated that, even with hydrogen moderation, a treatment of all collision sequences of fifth order or less in a faithful mock-up of the lattice was required to describe the end-leakage fraction accurately. In the case of nonhydrogenous moderators it was necessary to consider longer sequences. When all collision sequences of 10th order or less were treated in a faithful mock-up of the lattice, 80% of the total end-escape fraction was accounted for in a rigorous manner and a good estimate of the end-escape spectrum was obtained down to 25 kev. Escape fraction and spectrum estimates based on numerical integration over all scattering sequences of second order or less in a faithful lattice mock-up are shown to be misleading. The two essential factors which caused the lattice and homogeneous model results to differ were the smaller mean free path and larger absorption cross section of the homogeneous model and the directional character of the mean free path and absorption cross section in the lattice. As a result, longer collision sequences are required, on the average, to produce escape in the homogeneous model than in the lattice.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25862

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractA general expression for the intensity of unscattered gamma rays at points on the axis of a cylindrical absorber, surrounded by a ring-shaped self-absorbing source of rectangular cross section, is derived in terms of two integrals that have been evaluated on the IBM 704 computer. The results are presented in the form of curves from which the intensity can be determined for a wide variety of cases. For points not on the axis of symmetry a solution is given for the special case of source with large peripheral dimensions.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25863

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe cold, clean, steel-reflected, final, SM-2 mock-up containing 36.4 kg U235and 61 g B10maintained criticality after a seven rod bank withdrawal of 6.974 in. and has an“excessK”(ΔKE) of 1520 cents. An infinite steel-water laminated reflector is worth approximately +85 cents over the infinite water reflected core. The measured reactivity coefficient, @ 2000 psi, ranges from–1.15 cents/°F @ 150°F to–5.20 cents/°F @ 510°F. The integral reactivity effect of raising the SM-2 core water temperature from 103 to 510°F @ 2000 psi and the water in the reflector coolant graph from 103 to 477°F @ 2000 psi is–889.7 cents. The average measured material coefficients for U235and B10are 0.157 cents/g and 42.54 cents/g, respectively. Without the benefit of flux suppressors the maximum to average power ratio of 7.28 occurs at the top of the fuel section of control rod C (withdrawn to 7.14 in.), and a ratio of 5.28 occurs at the bottom of stationary element 43 and symmetric elements.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25864

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe behavior of plutonium in melt refining of plutonium-bearing uranium alloys was studied as functions of the initial plutonium concentration in the charge, the time and temperature of refining, and the carbon impurity added to the charge. Under all conditions studied, the percentage recovery of plutonium in the purified metal was slightly lower than that of uranium. The concentration of plutonium in uranium-20 weight per cent plutonium-10 weight per cent fissium alloy (EBR-II type fuel) melt refined for three hours at 1300 or 1400°C was 0.31±0.23% lower than the plutonium concentration in metal charged to the process.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25865

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractThe release of the fission gases, xenon and krypton, from molten irradiated uranium was studied experimentally at total initial gas contents of 0.002–138 parts per million. At concentration levels anticipated in spent EBR-II fuels, over 99% of the xenon and krypton is expected to be removed from the molten metal.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25866

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor

摘要:

AbstractMelt refining of synthetic EBR-II alloy in oxide crucibles at temperatures between 1200 and 1400°C under an inert atmosphere resulted in a separation of rare earth elements, yttrium, and alkaline earth elements from ingot fractions. The rate of cerium removal is shown to behave as a first-order reaction. Cesium is quantitatively volatilized from highly irradiated uranium fuels refined at 1200°C for 4 hr.

ISSN:0029-5639    

DOI:10.13182/NSE61-A25867

出版商:Taylor&Francis    

年代:1961

数据来源: Taylor