## Abstract

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).

## Citation Formats

Sakurai, Yoshinori, Okuno, Hiroshi, and Naito, Yoshitaka.
Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations.
Japan: N. p.,
1991.
Web.

Sakurai, Yoshinori, Okuno, Hiroshi, & Naito, Yoshitaka.
Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations.
Japan.

Sakurai, Yoshinori, Okuno, Hiroshi, and Naito, Yoshitaka.
1991.
"Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations."
Japan.

@misc{etde_10117378,

title = {Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations}

author = {Sakurai, Yoshinori, Okuno, Hiroshi, and Naito, Yoshitaka}

abstractNote = {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).}

place = {Japan}

year = {1991}

month = {Sep}

}

title = {Effects of UO{sub 2}-fuel grain size on reactivity. Continuous energy Monte Carlo calculations}

author = {Sakurai, Yoshinori, Okuno, Hiroshi, and Naito, Yoshitaka}

abstractNote = {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).}

place = {Japan}

year = {1991}

month = {Sep}

}