TY - RPRT
TI - Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations
AB - Heterogeneity effects on reactivity of powdered or slurry fuel were studied through criticality calculations of three-dimensional tiny cells, which were infinitely arrayed and consisted of a spherical fuel pellet of 5 wt% {sup 235}U-enriched uranium dioxide surrounded by water; the diameter of the fuel pellet was varied from 0 (homogeneous) to 6 mm, keeping constant the volume ratio of water to fuel. Reaction rates were calculated by solving the continuous energy transport equations by the Monte Carlo method. The infinite-medium multiplication factor and its four-factors, and their fractional changes from the homogeneous system were obtained. The infinite-medium multiplication factor increased when the system changed from homogeneous to heterogeneous. The results of calculations confirmed that the reactivity increase mainly came from the resonance escape probability p; they also indicated that any uranium-fuel system of grain size less than 100 {mu}m could be treated homogeneous if a 0.3 % increment of reactivity was regarded small enough to be negligible. (author).
AU - Sakurai, Yoshinori [Kyoto Univ. (Japan)]
AU - Okuno, Hiroshi
AU - Naito, Yoshitaka
KW - 22 GENERAL STUDIES OF NUCLEAR REACTORS
KW - 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
KW - FUEL CELLS
KW - REACTIVITY
KW - URANIUM DIOXIDE
KW - MONTE CARLO METHOD
KW - HETEROGENEOUS EFFECTS
KW - WATER
KW - MULTIPLICATION FACTORS
KW - RESONANCE ESCAPE PROBABILITY
KW - PARTICLE SIZE
KW - CRITICALITY
KW - 220300
KW - 050700
KW - FUEL ELEMENTS
KW - FUELS PRODUCTION AND PROPERTIES
DO -
UR -
PB -
CY - Japan
PY - 1991
DA - 1991-09-01
LA - Japanese
J2 -
C1 - Japan Atomic Energy Research Inst., Tokyo (Japan)
C2 -
ER -