SPECTRAL SHIFT CONTROL REACTOR BASIC PHYSICS PROGRAM, QUARTERLY TECHNICAL REPORT NUMBER 3, JANUARY-MARCH 1961

Technical Report · Tue Oct 31 04:00:00 EST 1961

OSTI ID:4015473

A summary of the work accomplished during the third contract quarter (January 1 to March 31, 1961) on the Spectral Shift Control Reactor (SSCR) Basic Physics Program is presented. The major objective of the program is to determine basic physics parameters of tight-packed lattices of slightly enriched fuel in moderators consisting of D/sub 2/0--H/sub 2/0 mixtures. The concentration of the D/sub 2/0--H/sub 2/0 mixtures are varied so as to apply to the spectral shift concept. The required license amendment was issued, and the first critical experiment containing heavy water in the moderator (76.7 mole% D/sub 2/0) was performed with 4%enriched U0/sub 2/ fuel rods. Reported are measurements of the critical mass, critical buckling, thermal disadvdntage factor, cadmium ratio of U/ sup 235/ and U/sup 238/, epithermal neutr on spectrum, and the effect of moderator channels. The operating license for the room temperature exponential experiments was issued, and preliminary buckling measurements with (U/sup 235/ plus or minus Th)O/sub 2/ fuel in a moderator containing 80 mole% D/sub 2/0 were made. The results of hot exponential experiments at 70 to 400 deg F with 4%- enriched U0/sub 2/ fuel in light water moderator are also reported. Neutron age measurements in a lattice of ThO/sub 2/ rods in light water and 90 mole% D/sub 2/ 0, parallel and perpendicular to the rod axis, were completed and a preliminary analysis of the results is presented. Theoretical studies continued. The BPG computer code, which will be used to analyze experiments with D/sub 2/0 in the moderator, was refined by improving the methods of computing resonance absorption and the transport cross sections for fast neutrons. Alternate methods of computing Dancoff shielding in the lattice and resonance absorption in fertile material were considered, and BPG and PlMG calculations were compared to assess the importance of the choice of neutron spectrum in the reflector. Additional calculations in support of the experimental work also continued. (auth)

• Research Organization: Babcock and Wilcox Co. Atomic Energy Div., Lynchburg, Va.
• NSA Number: NSA-15-025575
• OSTI ID: 4015473
• Report Number(s): BAW-1220
• Country of Publication: United States
• Language: English

Related Subjects

BUCKLING
CONTROL
CRITICALITY
ENERGY RANGE
EPITHERMAL NEUTRONS
FUEL ELEMENTS
HEAVY WATER MODERATOR
MASS
MEASURED VALUES
MIXING
NEUTRON FLUX
NEUTRONS
POWER PLANTS
QUANTITY RATIO
REACTOR TECHNOLOGY
REACTORS
SPECTRAL SHIFT
SSCR
THERMAL NEUTRONS
THERMAL UTILIZATION
URANIUM DIOXIDE
VARIATIONS
WATER MODERATOR