[en] Drying tests were conducted on TMI-2 fuel canisters filled with simulated core debris. During these tests, canisters were dried by heating externally by a heating blanket while simultaneously purging the canisters' interior with hot, dry nitrogen. Canister drying was found to be dominated by moisture retention properties of a concrete filler material (LICON) used for geometry control. This material extends the drying process 10 days or more beyond what would be required were it not there. The LICON resides in a nonpurgeable chamber separate from the core debris, and because of this configuration, dew point measurements on the exhaust stream do not provide a good indication of the dew point in the canisters. If the canisters are not dried, but rather just dewatered, 140-240 lb of water (not including the LICON water of hydration) will remain in each canister, approximately 50-110 lb of which is pore water in the LICON and the remainder unbound water

[en] As part of the U. S. Department of Energy (DOE) sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL's Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR 1) experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed

[en] Radioisotopes labelled with halogen isotopes have been used since 1939 for te investigation of human thyroid disease. Today they are used widely for research using positron computed tomography, and gamma scintiscanning. This introduction is concerned mainly with the uses of fluorine, bromine and iodine-labelled compounds e.g. 2-fluoro-deoxy-glucose and L-6-fluorodopa and the gamma emitting isotopes and their use in positron computed tomography. (U.K.)

[en] The advantages of fluorine-18 labelled pharmaceuticals are discussed. The production of the radionuclide is mentioned, and a list of biologically important compounds, together with their proposed applications, is presented. Fluorine-18 labelled fluorocarbohydrates, fluoroaryl compounds, and labelled gases are described. (U.K.)

[en] ¹⁸F recoil labelling of trichlorofluoro-, dichlorodifluoro-, chlorotrifluoro- and tetrafluoromethane has been investigated. Mixtures of an appropriate substrate (0.3-2%) in neon were bombared with 14 MeV deuterons (²⁰Ne(d, α)¹⁸F reaction). All the above compounds were labelled in high activities by this technique. When tetrachloromethane was the substrate the major product was ¹⁸F-trichlorofluoromethane (approximately 95% of total gaseous activity). ¹⁸F-dichlorodifluoromethane was the major product (approximately 60 and approximately 70% respectively) when either trichlorofluoromethane or dichlorodifluoromethane was the substrate. The use of chlorotrifluoromethane as substrate produced ¹⁸F-dichlorodifluoromethane and ¹⁸F-tetrafluoromethane in significant amounts in addition to ¹⁸F-chlorotrifluoromethane (approximately 40%). Bombardment of mixtures of tetrafluoromethane in neon produced ¹⁸F-tetrafluoromethane (approximately 80%) together with other ¹⁸F-labelled gaseous products. The targetry and irradiation conditions are described. the volatile products were analysed by radio-gas chromatography. (author)

No abstract available

[en] The concept of radiation cooling with π pulses is presented and quantified with a theoretical analysis. Numerical analysis of π pulse cooling on the hydrogen Lyman-α transition is presented as an example. The cooling rate and limiting temperature are discussed and compared with steady-state radiation cooling

[en] An eight mode truncated spectral model based on Burgers' approximation to the one-dimensional Navier--Stokes equations is used to compute the Lyapunov dimension of the dynamical attractor for turbulence in a stable cloud layer. The model results are compared with the correlation dimension obtained earlier from a time series of radar Doppler and reflectivity signals from a turbulent layer in a marine stratus cloud. The analysis supports a weak coupling explanation for the lower correlation dimension found for the reflectivity time series compared with that for the Doppler time series. Turbulent Prandtl number emerges from the analysis as a flow parameter which can enlarge the dimension of the model's dynamical attractor, but the attractor dimension computed for the model remains lower than the radar Doppler correlation dimension. Linear stability analysis of the model's equilibrium states suggests that a nontruncated version of the model will possess an attractor which is also of lower dimension than the radar Doppler correlation dimension

No abstract available

No abstract available