DETECTING AND ELIMINATING FUEL ROD BOWING IN THE SRE
The second fuel loading of the Sodium Reactor Experiment was found to be unstable. The cause of the instabliity was traced to bowing of the individual fuel rods resulting in a fast positive power coefficient. Differential thermal expansion induced by a difference between fuel cladding temperatures on the outer sad inner sides of the cluster caused bowing. Hydraulic bowing caused by differences in the flow velocities inside and outside the cluster was also observed. Fuel rod bowing, and hence the reactor instability, was eliminated by wrapping the fuel rods with stainless steel wire. Sustained oscillations in the flux were observed at constant power. These oscillations caused resonant peaks in the reactor transfer function as measured by pile oscillation and noise analysis techniques. The oscillations were caused by cycling of the fuel temperatures which produced an oscillatory bowing motion of the rods. Flux oscillations and resonant peaks were eliminated when the fuel was wire wrapped. (auth)
- Research Organization:
- Atomics International, Div. of North American Aviation, Inc., Canoga Park, Calif.
- DOE Contract Number:
- AT(11-1)-GEN-8
- NSA Number:
- NSA-17-013680
- OSTI ID:
- 4736162
- Report Number(s):
- NAA-SR-7705
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EXPANSION
FUEL CANS
FUEL ELEMENTS
HYDRAULICS
LIQUID FLOW
LIQUID METAL COOLANT
MEASURED VALUES
NEUTRON FLUX
OSCILLATIONS
POWER PLANTS
REACTIVITY
REACTOR NOISE
REACTOR OSCILLATORS
REACTOR TECHNOLOGY
REACTORS
RODS
SODIUM
SRE
STABILITY
STAINLESS STEELS
STATISTICS
TEMPERATURE
TRANSFER FUNCTIONS
VARIATIONS
VELOCITY
WIRES