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U.S. Department of Energy
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KINETIC EXPERIMENTS ON WATER BOILERS-"A" CORE REPORT-PART II. ANALYSIS OF RESULTS

Technical Report ·
DOI:https://doi.org/10.2172/4812669· OSTI ID:4812669

The status of the analytic portion of the KEWB program at the time of completion of the spherical core experiments is summarized. Three computer programs were developed for use in this analytic effort. The first reassembles and smooths three decades of reactor power data read separately from oscillogram records of reactor excursions. It then computes the logarithmic derivative of the power, energy release, fuel solution temperature, and temperature compensated reactivity. The second program utilizes the space-independent neutron kinetics equations with any number of delayed neutron groups to determine the reactivity in the reactor from the power and its derivative. The third program solves the space-independent kinetics equations for the neutron flux from an input reactivity or initial period. Up to 50 reactivity feedback equations includirg delayed neutrons are provided for in this program. A mathematical model of the reactor investigated extensively was one containing six delayed neutron groups, conventional treatment of temperature reactivity compensation, and void compensation of reactivity induced by radiolytic gas void growth proportional to the product of reactor power and energy release. Partial mathematical solutions to the kinetic equations were derived for reactivity feedback proportional to prompt temperature and void growth according to the product of power and energy. These solutions apply where delayed neutrons can be neglected, which is the region of major interest. Expressions are available relating power and energy and defining the peak power and energy release to peak power in terms of basic reactor parameters. Experimental evidence, particularly the experimental inlmour curve, of another reactivity influencing mechanism was found present in the reactor at periods shorter than 10 msec. This mechanism was shown to behave as a delayed neutron group, having a mean delay time of approximately 2 msec and an abundance of 2%. A plausible origin of such neutrons was shown to be the reflector which thermalizes core neutrons and returns them to the core following a delay. (auth)

Research Organization:
Atomics International. Div. of North American Aviation, Inc., Canoga Park, Calif.
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
DOE Contract Number:
AT-11-1-GEN-8
NSA Number:
NSA-16-009658
OSTI ID:
4812669
Report Number(s):
NAA-SR-5416
Country of Publication:
United States
Language:
English