51 Matching Results

Search Results

Advanced search parameters have been applied.

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

Chemical assay of plutonium for safeguards

Description: From joint meeting of the American Nuclear Society and the Atomic Industrial Forum and Nuclear Enengy Exhibition; San Francisco, California, USA (11 Nov 1973). The plutonium-containing samples analyzed for nuclear safeguards purposes range from heterogeneous scrap materials to highly pure metal. The factors governing the selection of analytical methods are the quantities of plutonium represented by the sample and the representativeness of the sample. Product-type materials generally are characterized by high plutonium contents and homogeneity whereas scrap-type materials usually have low plutonium contents and are heterogeneous. Analytical methods that provide highly reliable measurements therefore are used for product materials and less reliable methods are acceptable for scrap materials. Analytical methodology used for plutonium assay for various nuclear fuel cycle materials with emphasis on Los Alamos Scientific Laboratory (LASL) practices is discussed. A major portion of this presentation is devoted to a system under development for scrap-type samples which involves a combination of high-temperature, pressurized, acid-dissolution attack; a gamma assay for low levels of plutonium in any resulting residue; and use of an automated spectrophotometer for measuring plutonium in the solubilized fraction. The isotopic analysis of plutonium is briefly discussed. Also, the status of physical standards for assay and isotopic measurement applications is reviewed. (auth)
Date: April 30, 1974
Creator: Jackson, D.D.; Rein, J.E. & Waterbury, G.R.
Partner: UNT Libraries Government Documents Department

Joint plant instrumentation program and integrated safeguards experiment. Final report

Description: Mixed (uranium-plutonium) oxide standards were prepared and utilized to qualify available nondestructive assay equipment (gamma spectrometers, neutron counters, and calorimeters). Equipment was evaluated during normal operation in a plutonium facility. Measured material balances were calculated for two separate fabrication campaigns. Plutonium material unaccounted for values of less than 0.5% based on the total throughput was obtained in the final balance. A special test was undertaken to compare the plutonium content of single pellets determined by available nondestructive assay methods with controlled potential coulometric values. The implications of both programs on safeguards are summarized. (auth)
Date: June 1, 1972
Creator: Wadekamper, D.C.; Bishop, D.M. & Hagie, L.T.
Partner: UNT Libraries Government Documents Department