Neutron multiplication in beryllium

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5016329

Hartley, R S

Integral neutron multiplication experiments have been performed using spherical shells of beryllium metal of 4.6-, 6.99-, 7.87-, 9.38-, 13.8-, and 19.9-cm thickness. Neutron leakage, from {sup 252}Cf and a DT neutron source normalized with an associated particle detector, were measured with a Bonner sphere spectrometer system. The neutron fluence was obtained by processing the room-returned and air-scattered corrected count-rate data with a Bonner sphere spectrum unfolding routine and a weighted Bonner sphere technique. The neutron multiplication was obtained directly by comparing the normalized neutron leakage fluence with and without beryllium present. The neutron leakage spectra were calculated for each shell using the discrete ordinates codes ANISN and ONEDANT with ENDF/B-IV and ENDF/B-V respectively. The cross sections from ENDF/B-V included the most current cross section revisions from the Los Alamos National Laboratory. A comparison of the leakage multiplication, calculated using the two versions of evaluated nuclear data, indicate that corrections have been made to the energy-angle distribution of the secondary neutrons in ENDF/B-V resulting in a lower neutron leakage multiplication for shells greater than 9.38-cm thickness. The measured {sup 252}Cf neutron leakage multiplication is 22% higher than the ANISN-ENDF/B-IV calculated leakage multiplication for the 4.6-cm shell thickness, within 4% for the 6.99-cm thickness, and at least 29% lower than the calculated leakage multiplication for the 19.9-cm shell thickness.

• Research Organization: Texas Univ., Austin, TX (USA)
• OSTI ID: 5016329
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
651100* -- Nuclear Physics-- Experimental Techniques-- (1980-)
651220 -- Nuclear Properties & Reactions
A=1-5
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALKALINE EARTH METALS
ALPHA DECAY RADIOISOTOPES
BERYLLIUM
CALCULATION METHODS
CALIFORNIUM 252
CALIFORNIUM ISOTOPES
DATA
ELEMENTS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HEAVY NUCLEI
INFORMATION
ISOTOPES
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NEUTRON SPECTROSCOPY
NUCLEI
NUMERICAL DATA
RADIOISOTOPES
SPECTROSCOPY
YEARS LIVING RADIOISOTOPES