THERMAL DEFLECTION OF THE YANKEE FUEL ASSEMBLY FROM LINEAR AND NON-LINEAR TEMPERATURE GRADIENTS

Technical Report · Sun Mar 01 04:00:00 EST 1959

DOI:https://doi.org/10.2172/4262983· OSTI ID:4262983

Johnson, C. G.

Theoretical conditions were investigated for determining the thermal deflection of the definitive design unshrouded Yankee fuel assembly and the compromise design fuel assembly. In addition, an experimental study was completed on the thermal deflection of the compromise design fuel assembly from linear and nonlinear temperature gradients. All of the theoretical analyses performed on the definitive design clearly indicate that excessive bowing in the order of 0.150 inch may occur within the reactor during normal operation. Slnce the nominal clearance available in this design between a fuel assembly and an adjacent control rod is about 0.120 inch, interference between a fuel assembly and its adjacent control rod can occur, resulting in restricting the movement of the control rod. When buildup of mechanical tolerances are considered, this condition becomes more severe. Redesign of the definitive design fuel assembly thus became mandatory to prevent interference with the movement of control rods. The compromise fuel assembly design evolved as a result of these considerations. The compromise design employs the use of the brazed ferrule fuel sub-assembly design concept, but incorporates several fundamental changes in design that increase clearances adjacent to the control rod to reduce thermal bowing of the complete assembly. The compromise fuel assembly is allowed to deflect under thermal distortion to a limited extent and is designed so that under the worst set of circumstances the available clearance between the fuel assembly and control rod is at least 0.001 inch. The compromise design therefore, constitutes a safe design from a thermal deflection standpoint. (auth)

• Research Organization: Westinghouse Electric Corp. Atomic Power Dept., Pittsburgh
• NSA Number: NSA-13-013101
• OSTI ID: 4262983
• Report Number(s): YAEC-80
• Country of Publication: United States
• Language: English

Related Subjects

CONFIGURATION
CONTROL ELEMENTS
DEFORMATION
DISTRIBUTION
EXPANSION
FUEL ELEMENTS
MOTION
PLANNING
QUANTITATIVE ANALYSIS
REACTOR CORE
REACTOR SAFETY
REACTORS
RODS
TEMPERATURE
YAEC