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COST OF BLENDING URANIUM OF TWO DIFFERENT U$sup 235$ ISOTOPIC ENRICHMENTS. Values of Uranium from the "USAEC Unclassified Pricing List"

Description: >Cost tables and instructions for calculating the cost of blending two different isotopic enrichments of U/sup 235/ to form an intermediate assay are presented. A sample calculation is included and information on reactor fuel cycles is given. (J. R. D.)
Date: October 14, 1958
Partner: UNT Libraries Government Documents Department

Tables of Two U$sup 235$ Fission Spectra

Description: The U/sup 235/ fission spectrum is tabulated as a function of energy for two analytic representations. The table contains the distribution functions, their first derivatives, and their first integrals up to 10 Mev. (auth)
Date: October 1, 1957
Creator: Howerton, R. J.; Bengston, J. & French, S. J.
Partner: UNT Libraries Government Documents Department

Survey of available technology for auditing $sup 235$U enrichment in cascade equipment

Description: A search for possible nondestructive techniques which might be utilized by a safeguards inspection team for auditing /sup 235/U enrichment of UF/sub 6/ in gaseous diffusion cascade equipment without access to the UF/sub 6/ itself was carried out at the ORGDP. The work included a literature survey of safeguards techniques in use by others, and a search for other methods or equipment which might be applied to the present objective. Various possible methods are evaluated briefly. Probable limited access to cascade equipment precludes the use of methods involving bulky equipment, including neutron and gamma generators, coincident or anticoincident counters and high energy isotopic neutron sources of sufficient strength to produce a measurable fission rate in /sup 238/U which requires large shields. Irradiation with low energy neutrons followed by detection of fission events and passive gamma measurements could provide information on the /sup 235/U content, but not on the 2/sup 238/U. Two methods upon which preliminary investigations were carried out are considered to warrant further development. The first involves a direct measurement of the /sup 235/U gamma radiation from UF/sub 6/ within a pipe and a measurement of the absorption of gamma rays from an external gamma source when these rays pass through the pipe walls and UF/sub 6/. The /sup 235/U gamma measurement indicates the amount of this isotope present, and the gamma absorption measurement, when corrected for pipe-wall absorption, indicates the total uranium present. Experimental tests indicated this method to be well within the scope of current technology. The tests included an evaluation of a commercially available ultrasonic gauge which could be used for pipe-wall thickness measurements. The second method involves the irradiation of the UF/sub 6/ with a moderated neutron source and the detection of gamma rays resulting from neutron capture in /sup 238/U and fissions induced in ...
Date: November 1, 1973
Creator: Bailey, J.C.
Partner: UNT Libraries Government Documents Department

Nondestructive assay of fissile material samples in support of nuclear safeguards

Description: From nuclear science symposium; San Francisco, California, USA (14 Nov 1973). Samples of fissile material can be assayed by bombarding with 300- to 600- keV neutrons and counting delayed neutrons from fission. Interrogating neutron energy selection is based upon considerations of sample penetrability and insensitivity of response to nonfissile isotopes. Significant cost savings in nuclear safeguards and quality control are possible. (auth)
Date: January 1, 1973
Creator: Evans, A.E. Jr.
Partner: UNT Libraries Government Documents Department

Neutron cross sections for uranium-235 (ENDF/B-VI release 3)

Description: The resonance parameters in ENDF6 (Release 2) U235 were adjusted to make the average capture and fission cross sections below 900 eV agree with selected differential capture and fission measurements. The measurements chosen were the higher of the credible capture measurements and the lower of the fission results, yielding a higher epithermal alpha. In addition, the 2,200 m/s cross sections were adjusted to obtain agreement with the integral value of K1. As a result, criticality calculations for thermal benchmarks, and agreement with a variety of integral parameters, are improved.
Date: May 1, 1996
Creator: Lubitz, C.
Partner: UNT Libraries Government Documents Department

VARIATIONS IN ISOTOPIC CONTENT OF NATURAL URANIUM

Description: Uranium ore concentrates from seventeen world sources were compared to a standard to determine variations in isotopic content. A spread of about 0.06% in U/sup 235/ content was indicated for the concentrates analyzed. Domestic sources showed much wider variations than those from other parts of the world. (auth)
Date: June 26, 1961
Creator: Smith, R.F.; Eby, R.E. & Turok, C.W.
Partner: UNT Libraries Government Documents Department

THE DEPLETION OF BURNABLE POISON IN ENDURANCE CALCULATIONS

Description: Methods of relating the bunnable poison concentration in a reactor to the fuel concentration during the life of the core are presented. These methcds correspond to the following ways of using bunnable poison: (1) in discrete lumps, (2) in a homogeneous rnixture with the fuel, and (3) a combination of these. Nuclear data relevant to the U/sup 235/-B/sup 10/ system are presented. (auth)
Date: March 1, 1960
Creator: Dahlberg, R.C. & Judge, F.D.
Partner: UNT Libraries Government Documents Department

Recoil Range of Fission Fragments in Zirconium

Description: The recoil ranges of fission fragruents in zirconium were measured by irradiating small pieces of a Zircaloy-2 ribbon containing 492 ppm of homogeneously dispersed U/sup 235/. The samples were wrapped in aluminum foil during the irradiation to catch the fission fragments escaping from the surface of the Zircaloy-2. Average values of 10.1 and 8.15 microns were obtained for the recoil ranges of the median light and heavy fission fragments, respectively; these values compare quite well with values calculated from empirical equations. (auth)
Date: November 1, 1959
Creator: Smith, E. R. & Frank, P. W.
Partner: UNT Libraries Government Documents Department

Filter Paper: Solution to High Self-Attenuation Corrections in HEPA Filter Measurements

Description: An 8 by 8 by 6 inch High Efficiency Particulate Air (HEPA) filter was measured as part of a uranium holdup survey in June of 2005 as it has been routinely measured every two months since 1998. Although the survey relies on gross gamma count measurements, this was one of a few measurements that had been converted to a quantitative measurement in 1998. The measurement was analyzed using the traditional Generalized Geometry Holdup (GGH) approach, using HMS3 software, with an area calibration and self-attenuation corrected with an empirical correction factor of 1.06. A result of 172 grams of {sup 235}U was reported. The actual quantity of {sup 235}U in the filter was approximately 1700g. Because of this unusually large discrepancy, the measurement of HEPA filters will be discussed. Various techniques for measuring HEPA filters will be described using the measurement of a 24 by 24 by 12 inch HEPA filter as an example. A new method to correct for self attenuation will be proposed for this measurement Following the discussion of the 24 by 24 by 12 inch HEPA filter, the measurement of the 8 by 8 by 6 inch will be discussed in detail.
Date: October 1, 2005
Creator: Oberer, R. B.; Harold, N. B.; Gunn, C. A.; Brummett, M. & Chaing, L. G.
Partner: UNT Libraries Government Documents Department