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A Uranium-Metal Exponential Experiment

Journal Article · · Nuclear Science and Engineering
OSTI ID:4121823
 [1]
  1. Los Alamos Scientific Laboratory (LASL), Los Alamos, NM (United States)
Certain conflicts arising from previous measurements of neutron flux parameters in the equilibrium spectrum of natural uranium were resolved. The parameters which were investigated are given along with "best" values as measured in this work: Material buckling, -0.0119 ± 0.0005 cm-2; Diffusion length, 9.17 ± 0.18 cm; U235/U238 fission cross-section ratio, 239 ± 7; Pu239/U238 fission cross-section ratio, 250 ± 16; Np237/U238 fission cross section ratio, 14.5 ± 0.5; and U238 inelastic scattering cross section, 2.00 ± 0.04 barns. The experiment was performed at the Pajarito critical assemblies facility utilizing two exponential columns of natural uranium, each 30.7-in. high, having diameters of 15 and 21 in. and excited by a small fast reactor. The system was outdoors, elevated some 11 ft above the ground level to reduce flux perturbations due to backscattering of neutrons. Perturbation corrected measurements in both columns made by several detection methods and with various source spectra agree to within experimental error and are consistent with calculated values.
Research Organization:
Los Alamos Scientific Laboratory (LASL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
DOE Contract Number:
W-7405-ENG-36
NSA Number:
NSA-15-006605
OSTI ID:
4121823
Journal Information:
Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Vol. 8; ISSN 0029-5639
Publisher:
Taylor & Francis
Country of Publication:
United States
Language:
English