Calculated NWIS signatures for enriched uranium metal

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:225391

Valentine, T E; Mihalczo, J T; Koehler, P E ^[1]

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1. Oak Ridge National Lab., TN (United States)

Nuclear Weapons Identification System (NWIS) signatures have been calculated using a Monte Carlo transport code for measurement configurations of a {sup 252}Cf source, detectors, and a uranium metal casting. NWIS signatures consist of a wide variety of time-and frequency-analysis signatures such as the time distribution of neutrons after californium fission, the time distribution of counts in a detector after a previous count, the number of times n pulses occur in a time interval, and various frequency-analysis signatures, such as auto-power and cross-power spectral densities, coherences, and a ratio of spectral densities. This ratio is independent of detection efficiency. The analysis presented here, using the MCNP-DSP code, evaluates the applicability of this method for measurement of the {sup 235}U content of 19-kg castings of depleted uranium and uranium with enrichments of 20, 40, 60, 80, 90, and 93.2 wt % {sup 235}U. The dependence of the wide variety of NWIS signatures on {sup 235}U content and possible configurations of a measurement system are presented. These preliminary calculations indicate short measurement times. Additional calculations are being performed to optimize the source-detector-moderator-casting configuration for the shortest measurement time. Although the NWIS method was developed for nuclear weapons identification, the development of a small processor now allows it to be also applied in a practical way to subcriticality measurements, nuclear fuel process monitoring and qualitative nondestructive assay of special nuclear material.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 225391
• Report Number(s): CONF-950787--
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
40 CHEMISTRY
CALIFORNIUM 252
DEPLETED URANIUM
ENRICHED URANIUM
FISSILE MATERIALS
IAEA SAFEGUARDS
MONITORING
NONDESTRUCTIVE ANALYSIS
NUCLEAR MATERIALS MANAGEMENT
NUCLEAR REACTION ANALYSIS
NUCLEAR WEAPONS DISMANTLEMENT
QUANTITATIVE CHEMICAL ANALYSIS
URANIUM 235
USES
Y-12 PLANT