Abstracts and Available Papers Presented at the
1999 International RERTR Meeting

REDUCED ENRICHMENT NEUTRONIC STUDY ON
HIGH POWER RESEARCH REACTOR

Peng Feng, Fu Rong
Nuclear Power Institute of China
P. O. Box 291 Chengdu, 610005 P. R. China

ABSTRACT

The FG2DB two dimensional two group diffusion/burnup code and the CELL few group cell parameter code with 69 groups neutron cross section database have been used for reduced enrichment neutronic study on high power research reactor with LEU fuel elements of uranium density 3.6 - 7.2 g/cm³ and cladding thickness 0.38 - 0.56 mm.  Results show the equivalence of fuel meat uranium density on the thickness changing.  Control rod worth and other operation safety parameters of core are acceptable.  Parts of the results have been fitted to linear or quadratic expression for easy application.  The minimum critical value, excess reactivity, cycle length, fast and thermal fluxes and integrated fluxes, etc. are given.  Analysis of these parameters shows that with the U-235 content increased by 20% or more, the LEU core main physical characteristics are similar to those of the HEU core; reduced enrichment almost has no influence on the fast neutron flux; the decreasing rate of the thermal neutron fluxes proportional approximately to the increasing rate of the U-235 content in fuel element; because of the cycle length prolonging, common radioisotope production and fuel element irradiation testing are apparently not influenced.