POWER AND FLOW RAMP STABILITY TESTS ON THE SRE
The existence of a relatively fast positive power coefficient, with a time constant comparable to that of the fuel Doppler effect (~10 sec) was confirmed by performing negative power ramps and recording the automatic fluxcontrolled shim-rod motion. Fuel bowing was found to be the cause, and was corrected by restraining the clusters with a helical wrap of stainless steel wire. Individual components of fuel bowing and the isothermal temperature coefficient of fuel and coolant were isolated by conducting a series of power ramps, flow ramps, and combined power and flow ramps. Close coupling betveen the fuel and coolant prevented separation of these coefficients by this method; but, appllcation of the calculated value for coolant of alpha /sub c/ = + 0.02 cents/ F deg gave an experimentally determined value for the fuel of alpha /sub f/=- 0.23 cents/F deg as compared to a calculated value of --0.25 cents/F deg . Wire wrapplng of all of the fuel clusters in the core reduced the power coefficient from +9 cents/Mw to --2 cents/Mw, showing that the very strong negative Doppler effect had become dominant. This core now has excellent self- regulation due to the strong net negative power coefficient. (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-16-026223
- OSTI ID:
- 4812857
- Report Number(s):
- NAA-SR-7250
- Country of Publication:
- United States
- Language:
- English
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