Neutronic analysis of a proposed plutonium recycle assembly

Statement of responsibility on title-page reads: George M. Solan David D. Lanning Bruce F. Momsen, and Edward E. Pilat"August 1975."Also issued as a Nucl. E. thesis, MIT Dept. of Nuclear Engineering, 1975Includes bibliographical references (pages 271-275)A method for the neutronic analysis of plutonium recycle assemblies has been developed with emphasis on relative power distribution prediction in the boundary area of vastly different spectral regions. Such regions are those of mixed oxide (Pu0 2 in natural U02 ) fuel pins relative to enriched uranium pins, or water regions relative to fuel pin regions. The basic analytical methods for determination of spectrum averaged constants are given in the following descriptions: (1) Generalized Mixed Number Density (GMND) group constants (based on Breen's Mixed Number Density Method) are generated by a modified version of the spectrum code LASER, called LASER-M. (2) THERMOS Corrected LASER-M (TCL) group constants are based on mixed oxide- uranium oxide and water region boundary modeling in one dimensional (slab) geometry with the integral transport code THERMOS.The LASER-M model, as modified by addition of ENDF/B-II thermal cross sections for the plutonium isotopes, is used to predict the criticality of experimental lattices of U02 - 2 w/o Pu0 2, and fair agreement is shown. LASER-M unit cell depletion calculations with Yankee Core I data (3.4 w/o U-235) to 40,000 MWD/MT and Saxton Core II data (6.6 w/o Pu02 in natural U02) to 20,000 MWD/MT show good isotopic agreement. Saxton Critical Reactor Experiment (CRX) lattice cores (19 x 19 rod array) consisting of a single fuel type region (mixed oxide or uranium oxide) or multiregions of both pin types were analyzed for relative power distribution comparisons. Cores with water slot regions were included. LASER-M Normal, LASER-M GMND and TCL two group constants were used with PDQ-7 in the calculations. GMND results were in excellent agreement compared to the good agreement of TCL for these cases of isolated spectral disturbances in an asymptotic core region.The methods were applied to a proposed plutonium recycle "island design" assembly in which a large control rod water region is in close proximity to a zoned mixed oxide region. The TCL method yielded significantly greater power peaking and mixed oxide region average power owing to the spectral influence of the water region explicitly accounted for in this method. Such a result is consistent with published calculations. It is concluded that infinite lattice spectrum calculations are insufficient to deal with spectrum effects more complex than those in the Saxton CRX experiments

Reactor physics project progress report no. 2

Statement of responsibility on title page reads: Editors: M.J. Driscoll, I. Kaplan, D.D. Lanning; Contributors: V. Agarwala, F.M. Clikeman, J.N. Donohew, M.J. Driscoll, G. T. Hamilton, T.L. Harper, Y. Hukai, I. Kaplan, T. J. Kelley, D.D. Lanning, T.C. Leung, E.L. McFarland, N.C. Rasmussen, S.S. Seth, J.M. Sicilian, G.E. Sullivan, A.T.Supple and T.J. Thompson"September 30, 1969.""MIT-3944-4."Includes bibliographical referencesProgress report no. 2; October 1, 1968 through September 30. 1969This is the second annual report in an experimental and theoretical program to develop and apply single and few element heterogeneous methods for the determination of reactor lattice parameters. During the period covered by the report, October 1, 1968 through September 30. 1969, work was primarily devoted to measurement of the heterogeneous fuel element parameters (F, rl and A) of 19- and 31- rod clusters of plutonium-containing fuel. Methods development research focused on determination of the epithermal absorption constant, A. Calculations and an analysis of data reported in the literature were made to assess the applicability of heterogeneous methods to H 20- moderated systems. Advanced gamma spectrometric methods using Ge(Li) detectors were applied to the analysis of prompt and delayed gamma spectra from fertile and fissile materials and from fuel elements. These methods were used successfully for nondestructive analysis of the composition of fuel elements. A feasibility study was performed on an in-pile gamma spectrometer. Two fuel pins irradiated to a burnup of approximately 20,000 MWD/MT in the Dresden reactor were received and preparations made for their analysis and use in reactor physics experiments.U. S. Atomic Energy Commission contract AT(30-1)-394

The Pedestal

198 p. ; 21 cm

Intermediate algebra

viii, 447 p.; 22 cm

On the Use of Critical Distance Theories for the Prediction of the High Cycle Fatigue Limit Stress in Notched Ti–6Al–4V ☆

Methods are investigated for predicting the high cycle fatigue (HCF) lives of notched cylindrical Ti–6Al–4V specimens using critical distance concepts that employ the stress distribution in the vicinity of the notch. Cylindrical fatigue specimens had circumferential V-notches with a range of elastic stress concentration factors (kt=1.97–4.07). Notched and unnotched specimens were cycled to failure using a step-loading technique to generate points on a Haigh (Goodman) diagram for a constant fatigue life of 106 cycles. Finite element solutions were generated to provide stress distributions for the notched gage sections. The stress distributions were used in the search for a critical distance over which the quantities of mean stress, stress range, or elastic strain energy may contribute to the fatigue process and can be correlated to similar quantities from smooth, unnotched specimens. If the decrease in the local stress ratio at the notch root for high applied stress ratio is accounted for in the analysis, trends independent of applied stress ratio were found in the calculated critical distances. Predictions based upon the results gave accuracy to within 12% of the experimental fatigue limit stresses and illustrate the method has promise for use in fatigue design of Ti–6Al–4V components