skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Subcriticality of two uranyl nitrate flat cylindrical tanks spaced in air by [sup 252]Cf-source-driven noise analysis

Journal Article · · Nuclear Technology; (United States)
DOI:https://doi.org/10.13182/NT93-3· OSTI ID:5982020

The subcritical neutron multiplication factors k for two parallel, axially separated, flat cylindrical tanks separated up to 57.91cm in air and containing enriched uranyl (93.1 wt% [sup 235]U) nitrate solution (71.6-cm-i.d. tanks, 8.91-cm solution thickness, 1.555 g/cm[sup 3] solution density, and 404g U/l uranium density) were measured by the [sup 252]Cf-source-driven noise analysis method with measured k values varying from 0.99 to 0.80. These measurements were performed at the Los Alamos National Laboratory (LANL) Critical Experiments Facility in 1989 and were part of the program of Westinghouse Idaho Nuclear Company (WINCO) to benchmark calculations for the design of the new storage system at Idaho National Engineering Laboratory. Initial subcriticality measurements by the source-jerk method at LANL had indicated that at a calculated neutron multiplication factor k = 0.95, the measured k was 0.975. This discrepancy was of concern to WINCO because the new storage facility was being designed with a k limit of 0.95, and thus, half of the criticality safety margin of the storage design was equal to the discrepancy between early measurements and calculations. The [sup 252]Cf-source-driven noise analysis measurements confirmed the validity of the calculational methods. In addition to providing the neutron multiplication factor from point-kinetics interpretation of the data, these measurements also provided the auto-power and cross-power spectral densities as a function of frequency, which can be calculated directly with recently developed Monte Carlo methods and thus could also be used to validate calculational methods and cross-section sets.

DOE Contract Number:
AC05-84OR21400
OSTI ID:
5982020
Journal Information:
Nuclear Technology; (United States), Vol. 103:3; ISSN 0029-5450
Country of Publication:
United States
Language:
English