The Future of Nuclear Energy: Facts and Fiction: An update using 2009/2010 Data

An update of our 2009 study, "The Future of Nuclear Energy, Facts and Fiction" using the 2009 and the available 2010 data, including a critical look at the just published 2009 edition of the Red Book, is presented. Since January 2009, eight reactors with a capacity of 4.9 GWe have been connected to the electric grid and four older reactors, with a combined capacity of 2.64 GWe have been terminated. Furthermore, 27 reactor constructions, dominated by China (18) and Russia (4), have been initiated. The nuclear fission produced electric energy in 2009 followed the slow decline, observed since 2007, with a total production of 2560 TWhe, 41 TWhe (1.6%) less than in 2008 and roughly 100 TWhe less than in the record year 2006. The preliminary data from the first 10 months of 2010 in the OECD countries indicate that nuclear power production in North-America remained at the 2009 levels, while one observes a recovery in Europe with an increase of 2.5% and a strong rise of 5% in the OECD Asia-Pacific area compared to the same period in 2009. Worldwide uranium mining has increased during 2009 by about 7000 tons to almost 51000 tons. Still roughly 18000 tons of the 2010 world uranium requirements need to be provided from the civilian and military reserves. Perhaps the most remarkable new data from the just published 2009 edition of the Red Book, are that (1) the best understood RAR (reasonable assured) and IR (inferred) resources, with a price tag of less than 40 US dollars/Kg, have been inconsistently absorbed in the two to three times higher price categories and (2) uranium mining in Kazakhstan is presented with a short lifetime. The presented mining capacity numbers indicate an uranium extraction peak of 28000 tons during the years 2015-2020, from which it will decline quickly to 14000 tons by 2025 and to only 5000-6000 tons by 2035.Comment: 29 pages including 3 pages of reference

An estimate of the noise shielding on the fuselage resulting from installing a short duct around an advanced propeller

A simple barrier shielding model was used to estimate the amount of noise shielding on the fuselage that could result from installing a short duct around a wing-mounted advanced propeller. With the propeller located one-third of the duct length from the inlet, estimates for the maximum blade passing tone attenuation varied from 7 dB for a duct 0.25 propeller diameter long to 16.75 dB for a duct 1 diameter long. Attenuations for the higher harmonics would be even larger because of their shorter wavelengths relative to the duct length. These estimates show that the fuselage noise reduction potential of a ducted compared with an unducted propeller is significant. Even more reduction might occur if acoustic attenuation material were installed in the duct

Preliminary measurement of the noise from the 2/9 scale model of the Large-scale Advanced Propfan (LAP) propeller, SR-7A

Noise data on the Large-scale Advanced Propfan (LAP) propeller model SR-7A were taken into the NASA Lewis 8- by 6-Foot Wind Tunnel. The maximum blade passing tone decreases from the peak level when going to higher helical tip Mach numbers. This noise reduction points to the use of higher propeller speeds as a possible method to reduce airplane cabin noise while maintaining high flight speed and efficiency. Comparison of the SR-7A blade passing noise with the noise of the similarly designed SR-3 propeller shows good agreement as expected. The SR-7A propeller is slightly noisier than the SR-3 model in the plane of rotation at the cruise condition. Projections of the tunnel model data are made to the full-scale LAP propeller mounted on the test bed aircraft and compared with design predictions. The prediction method is conservative in the sense that it overpredicts the projected model data

A possible explanation for the present difference between linear noise theory and experimental data for supersonic helical tip speed propellers

High speed turboprops are attractive candidates for future aircraft because of their high propulsive efficiency. However, the noise of their propellers may create a cabin environment problem for the aircraft powered by these propellers. The noise of some propeller models was measured, and predictions of the noise using a method based on the Ffowcs Williams-Hawkins equation were made. The predictions and data agree well at lower helical tip Mach numbers but deviate above Mach 1.0. Some possible reasons why the theory does not predict the data and focuses on improvement of the aerodynamic inputs as the most likely remedy are investigated. In particular, it is proposed that an increase in the drag and a decrease in the lift near the tip of the blade where the majority of the noise is generated, is warranted in the input to the theory