POWER PATTERNS AND FUEL BURNUP IN A HEAVY WATER-MODERATED POWER REACTOR FOR VARIOUS REFUELING SCHEMES

Technical Report · Thu Jun 01 04:00:00 EDT 1961

OSTI ID:4838074

Graves, C; Sullivan, R; Bobker, J; Beers, F

In a design study of various heavy water-moderated power reactors, it was concluded that a direct cycle plant using boiling D/sub 2/0 coolant had the most promise within the ground rules established by the United States Atomic Energy Commission. The particular design selected for further study is a pressure tube reactor with cold moderator and clustered-rod, natural UO/sub 2/ fuel elements clad with the effect of various refueling schemes on fuel exposure and power patterns for heavy water-moderated, natural uranium-fueled power reactors. The methods used in the study and the application of these methods to the 200 Mw/sub c/ full scale reactor are described. The methods are directed primarily toward the prediction of conditions in the equilibrium regime of operation where the reactivity history is the same for each successive fuel reloading cycle. Of the refueling schemes considered, the radial outward fuel shift with axial fuel inversion yielded the highest average burnup of discharged fuel, but at the expense of a high radial maximum to average power. The calculations indicated a significant improvement in average burnup of discharged fuel for refueling schemes incorporating axial fuel inversion. For the outward and inward radial fuel shifts, the use of axial fuel inversion resulted in increases in burnup of 15 and 20% respectively. The inversion process resulted in relatively small changes in the radial flux pattern, as indicated by the one- dimensional calculations. However, further two-dimensional calculations should be made to determine the probable over-all increase in maximum to average power caused by the inversion process and to obtain more accurate burnup values based on calculated axial flux patterns. In terms of low power costs, the inward radial fuel shift with axial fuel inversion appears to be the most promising of the schemes considered. However, the final choice of the refueling scheme and the number of radial regions must await detailed reactor optimization calculations which include the effects of core size, fuel burnup, and reactor downtime on over-all power costs. (auth)

• Research Organization: Nuclear Development Corp. of America, White Plains, N.Y.
• NSA Number: NSA-15-028812
• OSTI ID: 4838074
• Report Number(s): NDA-2131-24
• Country of Publication: United States
• Language: English

Related Subjects

BOILING
BUCKLING
BURNUP
CONFIGURATION
DISTRIBUTION
ECONOMICS
EQUATIONS
FUEL CANS
FUEL ELEMENTS
HEAVY WATER COOLANT
HEAVY WATER MODERATOR
MOTION
NATURAL URANIUM FUEL
NEUTRON FLUX
POWER
POWER PLANTS
PRESSURE
REACTOR CORE
REACTOR FUELING
REACTOR TECHNOLOGY
REACTORS
TUBES
URANIUM DIOXIDE
VARIATIONS
ZIRCALOY
ZIRCONIUM ALLOYS
ZONES