Calculated NWIS signatures for enriched uranium metal
- 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-; TRN: IM9621%%321
- Resource Relation:
- Conference: 36. annual meeting of the Institute for Nuclear Materials Management, Palm Desert, CA (United States), 9-12 Jul 1995; Other Information: PBD: 1995; Related Information: Is Part Of Institute of Nuclear Materials Management 36. annual meeting: Proceedings. Volume 24; PB: 1347 p.
- Country of Publication:
- United States
- Language:
- English
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