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Title: Feasibility of /sup 252/Cf source driven neutron noise measurements in water moderated reactors

Thesis/Dissertation ·
OSTI ID:5390056

Previous experiments in fast critical assemblies demonstrated a method of determining reactivity from power spectral density measurements with /sup 252/Cf. This method determines reactivity from properties of the reactor only at the subcritical state of interest, thus it does not require a calibration near delayed criticality. The interpretation of the measured data to obtain reactivity does not require knowledge of the relative or absolute values of the source intensity, knowledge of the detection efficiencies, or knowledge of the detection instrumentation frequency responses. An experiment was performed at the Pool Critical Assembly to evaluate the possibility of /sup 252/Cf source driven neutron noise spectral density measurements in light water moderated reactors. This experiment showed that using commercially available detectors, such measurements can be performed in a reasonable time, that is, the measurement of the quantity of interest (the ratio of spectral densities directly related to reactivity) at approx.12 dollars subcritical can be made to within 10% uncertainty in approx.15 min using detectors with efficiencies of 10/sup -3/ counts per reactor fission and approx.3-4 h using detectors with efficiencies of 10/sup -4/ counts per reactor fission. These first /sup 252/Cf source driven neutron noise spectral density measurements in a water moderated system showed that such measurements are possible and may be applicable to such water moderated systems as: light water reactors, fuel reprocessing, fuel fabrication, and fuel storage facilities. However, care is required in locating the source and the detectors to assure proper interpretability of the measured quantities.

Research Organization:
Tennessee Univ., Knoxville (USA)
OSTI ID:
5390056
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English