Spectral Shift Control Reactor Basic Physics Program: Measurement and Analysis of Uniform Lattices of Slightly Enriched UO₂ Moderated by D₂O-H₂O Mixtures

Spectral Shift Control Reactor Basic Physics Program: Measurement of k_∞ and Other Lattice Parameters by the Small Lattice Experiment Technique

“…The volume of aluminum in the walls and dividers was 79-4 in. 3 and 27.2 in. 3 , respectively, so that aluminum occupied 12.0 vol % of the test region disregarding the end plates.…”

“…3 and 27.2 in. 3 , respectively, so that aluminum occupied 12.0 vol % of the test region disregarding the end plates. The active length of the test region and void was 17.50 ±0.01 inches.…”

“…However, if ideal conditions are achieved, Equation 2-2 for the poisoned test region becomes 1 = (njf e p) p (l + 6 2°°5 ) p (2)(3) where the subscript p refers to the poisoned medium. Then the infinite medium multiplication factor of the unpoisoned medium is simply P-V 1 + 5 £) (2)(3)(4) In these experiments the change in n tn due to the shift in the thermal spectrum when the medium is poisoned is negligibly small, because n for U-235 is essentially constant over the thermal range. Therefore, Equation 2-4 can be written k _ = /CLU-1-V-P-V 1 + 5 "*> (2-5) p/V p py(i + 6S) P Another modification to Equation 2-4 can be made.…”

“…ency and reproducibility of the variables that affect null-reactivity measurements. The maximum effects of these variables are shown in The measurements were made by standard techniques used earlier in the SSCR critical experiment program, 3 As shown in geometry. Very small corrections for the differences in axial flux at the foil positions were also applied.…”

“…a Al = (5.4 ± 3.7) X lO" 3 £/in. 3 a Mg = (1.5 ± 1.0) X 10" 3 £/in. 3 Using this a^i for the 79.4 in.…”