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U.S. Department of Energy
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TIME BEHAVIOR OF GODIVA THROUGH PROMPT CRITICAL

Technical Report ·
OSTI ID:4355222

Studies were made of the time behavior of a bare spherical U/sup 235/ metal assembly (Godiva) following sudden increases in reactivity with essentially zero initial power level and no external neutron source. The highest final reactivity attained under controlled conditions was about 10 cents above prompt critical. In the region above prompt critical the observed fission rate increased exponentially until the decreasing reactivity from thermal expansion caused it to pass through a bell-shaped maximum or "burst." Following this burst, the fission rate dropped to a low-amplitude "tail" sustained by delayed neutrons and finally terminated upon automatic scramming of the assembly. Burst amplitudes corresponding to instantaneous power levels of 10,000 Mw were observed with durations under a millisecond. Excellent agreement was found between measured reactor periods and calculations based on recent delayed neutron data. Over-all burst behavior also was found to agree with theory based on a space independent one-group model. (auth)

Research Organization:
Los Alamos Scientific Lab., N. Mex.
DOE Contract Number:
W-7405-ENG-36
NSA Number:
NSA-12-001075
OSTI ID:
4355222
Report Number(s):
LA-2029
Country of Publication:
United States
Language:
English