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Description: The economics of waste disposal by pit storage when the geological location of the pits does not coincide with the location of the processing plant are considered. Optimum cooling times before shipment were determined for 250gallon batches of Purex-type waste. Three distances between processing and disposal sites, and three unit storage costs were considered. It was concluded that as the storage cost increases it becomes economical to ship shorter-cooled waste, and as the shipping distance increases, it becomes economical to store waste longer. In the case of 30/gal/yr storage, for 200 miles shipment, essentially no storage should be provided beyond that required for surge in filling carriers. For less highly irradiated material, the optima would shift in the direction of shorter cooling times. Data are tabulated and presented graphically. (C.H.)
Date: October 24, 1955
Creator: Zeitlin, H.R. & Ullmann, J.W.
Partner: UNT Libraries Government Documents Department


Description: The need for breeding does not appear to be highly cost for a moderately optimistic expanding nuclear power economy between 1960 and 2000. Since the expansion rate of the US nuclear economy is assumed to be high at least 2/3 of the U-235 recovered from natural uranium is used to supply reactor inventory. It is the remaining 1/3 of the available U-235 that can be saved by breeder breeders or a breeder and converter are the doubling time and a parameter expressing the total fissile inventory per magawatt of electricity. In fact, the need for new raw material in any given year is reduced more by specific power than by changing from a converter to a value of total inventory per magawatt of electricity and the content and value of plutonium or U-233 than on raw material cost. The use of 12% vs. 4% annual lease charge can change the inventory costs more significantly than either the Pu (or U-233)/U-235 value ratio or raw material cost. Net fuel burn costs vary more with the product of net conversion ratio and Pu (or U-233)/U-235 value ratio than with the cost of raw material. (auth)
Date: January 20, 1959
Creator: Arnold, E.D. & Ullmann, J.W.
Partner: UNT Libraries Government Documents Department


Description: Reasons for storage to allow decay of irradiated fuel elements and possible methods of storage are given. The effects on storage and inventory costs of fuel element composition plant size, element geometry, reactor type, methods of irradiation and recycle, and type of metallurgic al handling are discussed. Estimates and comparisons are included for the decay for several typical fuels. The special problems associated with thorium fuel elements are considered. (auth)
Date: April 1, 1956
Creator: Ullmann, J.W. & Arnold, E.D.
Partner: UNT Libraries Government Documents Department

(n,p) reaction at 60 MeV on ND-2 targets. [M1 strength, angular distribution, transitions, giant resonance, cross sections]

Description: Various results are presented on energy levels of the isobaric analog resonances produced in the (n,p) reaction on /sup 7/Li, /sup 9/Be, /sup 27/Al, /sup 58/ /sup 60/ /sup 62/ /sup 64/Ni, /sup 90/Zr, and /sup 209/Bi targets. The emphasis is on qualitative features of the data through a comparison with existing results from other nuclear probes as well as observed properties of the isovector transitions anticipated from known isospin selection rules. 21 references. (JFP)
Date: January 1, 1979
Creator: King, N.S.P. & Ullmann, J.L.
Partner: UNT Libraries Government Documents Department


Description: The Zirflex and Sulfex processes for chemical decladding Zircaloy or stainless-steel-clad UO/sub 2/ power reactor fuels were successfully demonstrated at irradiation levels as high as 28,200 Mwd/t. The Zircaloy jackets were dissolved in boiling 6 M NH/sub 4/F-- 1 M NH/sub 4/NO/sub 3/, and the stainless steel jackets were dissolved in refluxing 4 M H/sub 2/SO/sub 4/. Both processes gave average soluble losses of uranium and plutonium to the decladding reagents of about 0.05%. Centrifugation or filtration of the highly radioactive decladding waste solutions was required to recover UO/sub 2/ fines produced by fracture of the UO/sub 2/. The fines were recycled and dissolved with the UO/sub 2/ cores in boiling 4 M HNO/sub 3/ solution. About 5 to 6 hr were required for complete dissolution of the UO/sub 2/ core to produce terminal concentrations of 100 g of uranium per liter and 3 M HNO/sub 3/. The core solution was a suitable solvent extraction feed after clarification and adjustment of plutonium valence with sodium nitrite. One cycle of the modified Purex process, in Mini mixersettlers, using 100-g-uranium-per-liter feed solutions, gave losses of uranium and plutonium to the raffinate of less than 0.1%, and gross gamma decontamination factors of about 1.5 x 10/sup 4/ for the uranium product and about 5 x 10/sup 3/ for the plutonium product. High purity n-dodecane diluent for the 30% TBP solvent retarded the formation of nonremovable uranium-retaining degradation products in the solvent by factors of up to 20, compared to Amsco- diluted TBP as measured by the uranium content of the washed solvent after six simulated cycles through the modified Purex process. The feed solutions were prepared from fuel specimens irradiated to 13,000 Mwd/t and cooled about 1 year. (auth)
Date: May 23, 1963
Creator: Goode, J.H.; Baillie, M.G. & Ullmann, J.W.
Partner: UNT Libraries Government Documents Department


Description: Calculations are given for eighteen stainless steel clad helium bonded specimens of UO/sub 2/-ThO/sub 2/ containing normal U to be placed in 6 holes in a holder in a position of the ORR not to exceed a peak unperturbed flux of 4 x 10/ sup 14/ n/ cm/sup 2//sec and irradiated to a peak nvt of 1.96 x 10/sup 21/
Date: June 1, 1959
Creator: Ullmann, .J .W
Partner: UNT Libraries Government Documents Department


Description: The effect of irradiation on the hydrolytic behavior of uranium monocarbide as related to the aqueous chemical processing of these reactor fuels is being investigated. The fabrication, evaluation, and encapsulation of the UC in niobium prior to irradiation is described. Uranium monocarbide buttons were prepared by arc-melting 1.51%enriched uranium metal with the stoichiometric quantity of spectroscopic-grade carbon. The buttons were then remelted and drop- cast into graphite thimbles 3/8 in. dia, and 3 in. long. The cylindrical castings were surface ground and cut into 0.17 in.-thick pellets, which were then polished. Preirradiation evaluation included metallography, chemical analysis, and hydrolysis studies. Microstructures of the final pellets indicated that the monocarbide was nearly stoichiometric; however, some alpha -uranium was present along with carbon contamination from the graphite thimbles. The use of tungsten- tipped electrodes in the arc-melting operation introduced about 0.3% of tungsten impurity. The composition of the pellets, as estimated from hydrolysis studies and chemical analyses was 92% UC, 3.5% UC/sub 2/, 4.0% uranium metal, and 0.3% WC. The UC pellets were encapsulated in niobium and subsequently shrunk-fit into a stainless steel cladding. The capsules were sealed by heliarc welding in a helium atmosphere chamber. (auth)
Date: April 1, 1963
Creator: Bradley, M.J.; Ferris, L.M.; Hikido, T. & Ullmann, J.W.
Partner: UNT Libraries Government Documents Department

Preliminary measurement of the /sup 235/U(n,f) cross section up to 750 MeV

Description: The recently commissioned high energy white neutron source was used to measure the neutron fission cross section of /sup 235/U in the energy range from 0.6 to 750 MeV. The shape of the cross section from 0.6 to 20 MeV agrees well with previous reported data. Absolute values for the /sup 235/U(n,f) cross section from 20 MeV to 750 MeV were obtained by normalizing the measured shape of the cross section to data in the 10 to 20 MeV range. 12 refs., 9 figs.
Date: October 1, 1987
Creator: Rapaport, J.; Ullmann, J.; Nelson, R.O.; Seestrom-Morris, S.; Wender, S.A. & Haight, R.C.
Partner: UNT Libraries Government Documents Department

A study of the /sup 235/U(n,f) cross section in the 3 to 30 MeV energy region

Description: The /sup 235/U(n,f) cross section is often considered the most favorable of the neutron cross section standards. Above a few MeV, however, the uncertainties are still unacceptably high, except for the 14 MeV region. In an effort to improve the accuracy of this cross section, measurements have been initiated at the new target 4 facility at the Los Alamos National Laboratory (LANL) 800 MeV proton accelerator. This target provides an intense source of high energy neutrons at the 20 meter flight path used in the present study. The fission reaction rate is determined with a fast parallel plate ionization chamber designed at LANL while the neutron fluence is being measured with an annular proton recoil telescope whose properties were carefully studied earlier at the National Bureau of Standards (NBS). This detector provides satisfactory performance for neutron energies up to about 30 MeV. Possible use of this detector at higher neutron energies where the recoil proton range exceeds the solid state detector thickness is being investigated. The measurements provide the shape of the /sup 235/U(n,f) cross section relative to the hydrogen scattering cross section. The data will be normalized to the very accurately known values at 14 MeV. Experimental tests, diagnostic studies and preliminary cross section determinations have been completed and will be reported. 7 refs., 5 figs., 1 tab.
Date: January 1, 1988
Creator: Carlson, A.D.; Wasson, O.A.; Lisowski, P.W.; Ullmann, J.L. & Hill, N.W.
Partner: UNT Libraries Government Documents Department

APT radionuclide production experiment

Description: Tritium ({sup 3}H, a heavy isotope of hydrogen) is produced by low energy neutron-induced reactions on various elements. One such reaction is n+{sup 3}He {yields}>{sup 3}H+{sup 1}H in which {sup 3}He is transmuted to tritium. Another reaction, which has been used in reactor production of tritium, is the n+{sup 6}Li {yields}> {sup 3}H+{sup 4}He reaction. Accelerator Production of Tritium relies on a high-energy proton beam to produce these neutrons using the spallation reaction, in which high-energy proton beam to produce these neutrons using the spallation reaction, in which high-energy protons reacting with a heavy nucleus produce a shower of low-energy neutrons and a lower-mass residual nucleus. It is important to quantify the residual radionuclides produced in the spallation target for two reasons. From an engineering point of view, one must understand short-lived isotopes that may contribute to decay heat. From a safety viewpoint, one must understand what nuclei and decay gammas are produced in order to design adequate shielding, to estimate ultimate waste disposal problems, and to predict possible effects due to accidental dispersion during operation. The authors have performed an experiment to measure the production of radioisotopes in stopping-length W and Pb targets irradiated by a 800 MeV proton beam, and are comparing the results to values obtained from calculations using LAHET and MCNP. The experiment was designed to pay particular attention to the short half-life radionuclides, which have not been previously measured. In the following, they present details of the experiment, explain how they analyzed the data and obtain the results, how they perform the calculations, and finally, how the experimental data agree with the calculations.
Date: July 2, 1994
Creator: Ullmann, J. L.; Gavron, A. & King, J. D.
Partner: UNT Libraries Government Documents Department

Thick target spallation product yields from 800 MeV protons on tungsten

Description: A number of newly-conceived accelerator based technologies will employ medium-energy particles stopping in thick targets to produce large numbers of neutrons. It is important to quantify the residual radionuclides in the target because one must understand what nuclei and decay gammas are produced in order to design adequate shielding, to estimate ultimate waste disposal problems, and to predict possible effects of accidental dispersion during operation. Because stopping-length targets are considered, radionuclide production must be known as a function of energy. Moreover, secondary particle production, mostly neutrons, implies a need to be able to calculate particle transport. To test the overall ability to calculate radionuclide yields, a thick-target measurement was carried out and the results compared to detailed calculations. Although numerous measurements of thin-target spallation yields have been made, there have been only a few measurements on thick systems. The most complete study showed results for Pb and U systems. In this contribution, the authors report on measurements made for a stopping-length W target. Special efforts were made to measure short-lived isotopes, and reliable data on isotopes with two or three minute half-lives were obtained.
Date: July 1, 1994
Creator: Ullmann, J. L.; Staples, P. & Butler, G.
Partner: UNT Libraries Government Documents Department

Unfolding the fission prompt gamma-ray energy and multiplicity distribution measured by DANCE

Description: The nearly energy independence of the {gamma}-ray efficiency and multiplicity response for the DANCE array, the unusual characteristic elucidated in our early technical report (LLNL-TR-452298), gives one a unique opportunity to derive the true prompt {gamma}-ray energy and multiplicity distribution in fission from the measurement. This unfolding procedure for the experimental data will be described in details and examples will be given to demonstrate the feasibility of reconstruction of the true distribution.
Date: October 16, 2010
Creator: Chyzh, A; Wu, C Y; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J et al.
Partner: UNT Libraries Government Documents Department

Fission prompt gamma-ray multiplicity distribution measurements and simulations at DANCE

Description: The nearly energy independence of the DANCE efficiency and multiplicity response to {gamma} rays makes it possible to measure the prompt {gamma}-ray multiplicity distribution in fission. We demonstrate this unique capability of DANCE through the comparison of {gamma}-ray energy and multiplicity distribution between the measurement and numerical simulation for three radioactive sources {sup 22}Na, {sup 60}Co, and {sup 88}Y. The prospect for measuring the {gamma}-ray multiplicity distribution for both spontaneous and neutron-induced fission is discussed.
Date: August 24, 2010
Creator: Chyzh, A; Wu, C Y; Ullmann, J; Jandel, M; Bredeweg, T; Couture, A et al.
Partner: UNT Libraries Government Documents Department

High energy neutron radiography

Description: High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos.
Date: June 1, 1996
Creator: Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G. et al.
Partner: UNT Libraries Government Documents Department