6 Matching Results

Results open in a new window/tab.

Pre-equilibrium decay processes in energetic heavy ion reactions (open access)

Pre-equilibrium decay processes in energetic heavy ion reactions

The Boltzmann master equation (BME) is defined for application to precompound decay in heavy ion reactions in the 10 100 MeV/nucleon regime. Predicted neutron spectra are compared with measured results for central collisions of /sup 20/Ne and /sup 12/C with /sup 165/Ho target nuclei. Comparisons are made with subthreshold ..pi../sup 0/ yields in heavy ion reactions between 35 and 84 MeV/nucleon, and with the ..pi../sup 0/ spectra. The BME is found to be an excellent tool for investigating these experimentally observed aspects of non-equilibrium heavy ion reactions. 18 refs., 8 figs.
Date: April 15, 1986
Creator: Blann, M.
System: The UNT Digital Library
Liquid nitrogen cooling considerations of the compact ignition tokamak (open access)

Liquid nitrogen cooling considerations of the compact ignition tokamak

An analytical procedure was developed to estimate the cooldown time between pulses of the Compact Ignition Tokamak (CIT) utilizing liquid nitrogen. Fairly good agreement was obtained between the analysis results and those measured in the early fusion experimental devices. The cooldown time between pulses in the CIT is controlled by the energy disposition in the inner leg of the TF coil. A cooldown time of less than one hour is feasible for the CIT if fins are used in the cooling channels. An R and D experimental program is proposed to determine the actual cooldown time between pulses since this would be considered an issue in the conceptual design of the CIT.
Date: June 15, 1986
Creator: Dabiri, A. E.
System: The UNT Digital Library
Nuclear hardening of optical coatings: enhanced energy sharing concept. Revision 1 (open access)

Nuclear hardening of optical coatings: enhanced energy sharing concept. Revision 1

Satellite component hardening requirements in the early 1970's led to the development of the enhanced energy sharing concept (EESC) for optical mirror coatings. The idea was to increase the survivability of aluminum coated fused silica mirrors to prompt energy deposition by interposing a thick layer of beryllium between the aluminum and the substrate. Separating the materials of higher Z by the low Z beryllium redistributes the deposited heat load over a larger volume and reduces the maximum temperature in the aluminum film. Theoretical analyses of heat transfer during and after an energy input pulse supported this concept and subsequent above-ground and underground tests confirmed the greater survivability of this mirror design. In the sections that follow we give an insight into the physical mechanisms responsible for nuclear radiation deposition and temperature rise. This is followed by a review of calculations of melt fluence for several mirror constructions taking into account only the dominant deposition mechanisms and heat flow.
Date: January 15, 1986
Creator: Edwards, D. F.; Gillespie, C. H.; Saito, T. T.; Wirtenson, G. R.; Schall, P. & Childs, W.
System: The UNT Digital Library
Passive dosimeters other than film and TLDs (thermoluminescent dosimeter) (open access)

Passive dosimeters other than film and TLDs (thermoluminescent dosimeter)

This presentation will describe CR-39 plastic as a personnel neutron dosimeter. Recent research at LLNL and elsewhere has resulted in the development of a dosimetry system that is superior to any personnel neutron dosimeter previously available. The author describes the features of the dosimetry system and the new etching procedures and techniques in detail. Most of the research was done at the LLNL and has been supported as a part of the DOE Neutron Dosimetry Upgrade Program. 10 refs., 4 figs., 1 tab.
Date: May 15, 1986
Creator: Hankins, D.E.
System: The UNT Digital Library
Laboratory performance testing of an extruded bitumen containing a surrogate, sodium nitrate-based, low-level aqueous waste (open access)

Laboratory performance testing of an extruded bitumen containing a surrogate, sodium nitrate-based, low-level aqueous waste

Laboratory results of a comprehensive, regulatory performance test program, utilizing an extruded bitumen and a surrogate, sodium nitrate-based waste, have been compiled at the Oak Ridge National Laboratory (ORNL). Using a 53 millimeter, Werner and Pfleiderer extruder, operated by personnel of WasteChem Corporation of Paramus, New Jersey, laboratory-scale, molded samples of type three, air blown bitumen were prepared for laboratory performance testing. A surrogate, low-level, mixed liquid waste, formulated to represent an actual on-site waste at ORNL, containing about 30 wt % sodium nitrate, in addition to eight heavy metals, cold cesium and strontium was utilized. Samples tested contained three levels of waste loading: that is, forty, fifty and sixty wt % salt. Performance test results include the ninety day ANS 16.1 leach test, with leach indices reported for all cations and anions, in addition to the EP Toxicity test, at all levels of waste loading. Additionally, test results presented also include the unconfined compressive strength and surface morphology utilizing scanning electron microscopy. Data presented include correlations between waste form loading and test results, in addition to their relationship to regulatory performance requirements.
Date: December 15, 1986
Creator: Mattus, A. J. & Kaczmarsky, M. M.
System: The UNT Digital Library
Glovebox enclosed dc plasma source for the determination of metals in plutonium (open access)

Glovebox enclosed dc plasma source for the determination of metals in plutonium

The direct current plasma source of a Beckman Spectraspan IIIB emission spectrometer was enclosed in a glovebox at Lawrence Livermore National Laboratory in December 1982. Since that time, the system has been used for the routine determination of alloy and impurity metals in plutonium. This paper presents the systematic steps involved in developing the glovebox and gives information regarding performance of the plasma in the glovebox and the effectiveness of containment of plutonium. 8 refs., 9 figs., 3 tabs.
Date: January 15, 1986
Creator: Morris, W.F.
System: The UNT Digital Library