Accession Number : AD0646630

Title :   MEASUREMENT OF NEUTRON SPECTRUM, AGE, AND DIFFUSION LENGTH IN CONCRETE,

Corporate Author : VIRGINIA UNIV CHARLOTTESVILLE DEPT OF NUCLEAR ENGINEERING

Personal Author(s) : Lim,Gene M. ; Williamson,T. G. ; Johnson,W. Reed

Report Date : JAN 1967

Pagination or Media Count : 30

Abstract : Activation foil detectors were used to measure the fast-neutron spectrum, slowing-down age, and thermal-diffusion length in concrete. The neutron source was a uranium fission plate placed in the graphite thermal column of the University of Virginia Reactor. Experimental concrete slabs were placed in the concrete biological shield of the reactor so that the medium was essentially infinite in the lateral direction. Indium, magnesium, and aluminum threshold foils were used to map the fast flux; indium, gold, tungsten, and manganese resonance foils to measure the neutron age; and indium and gold foils to measure the thermal neutron distribution. The fast spectrum retains essentially the fission shape with a slight dip in the 3- to 5-MeV range. The measured ages are essentially the same, l49 cm to the indium, gold, and tungsten resonances and 126 sq cm to the manganese resonances. The thermal diffusion length was measured as 6.0 plus or minus 0.5 cm. (Author)

Descriptors :   (*NEUTRON SPECTRUM, *CONCRETE), NEUTRON AGE, FAST NEUTRONS, THERMAL DIFFUSION, FOILS(MATERIALS), REACTOR SHIELDING MATERIALS, MEASUREMENT, THERMAL NEUTRONS

Subject Categories : Ceramics, Refractories and Glass
      Fission Reactor Physics
      Fission Reactor Materials
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE