[en] The Idaho National Engineering and Environmental Laboratory (INEEL) is investigating a Brayton cycle efficiency improvement on a High Temperature Gas-cooled Reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. In this project, we investigate using SuperCritical (SC) carbon dioxide as a secondary side fluid to enhance the Brayton efficiency. INEEL's preliminary calculations on the Brayton cycle indicate that SC CO₂ has 53% cycle efficiency versus 47% for helium for the reference pebble bed reactor design that MIT and INEEL developed. The higher efficiency is achieved at a lower turbine inlet temperature for SC CO₂, 814.5 .deg. C versus 875.7 .deg. C for helium. The higher density of SC CO₂ in the power conversion unit results in less work used to compress the CO₂, which contributes to higher work output from the power turbine resulting in a higher efficiency for the SC CO₂ Brayton cycle. The use of SC CO₂ as a coolant in the HTGR secondary is very attractive because we can increase the core outlet temperature, which will increase the plant net efficiency to greater than 58%. This paper includes preliminary calculations of the steady state overall Brayton cycle efficiency based on the pebble bed reactor reference design (helium as the working fluid) and compares those results with a CO₂ Brayton cycle

[en] Oxygen, carbon dioxide, and carbon monoxide have been added to the RELAP5-3D computer code as noncondensable gases to support analysis of high temperature gas-cooled reactors. Models of these gases are required to simulate the effects of air ingress on graphite oxidation following a loss-of- coolant accident. Correlations were developed for specific internal energy, thermal conductivity, and viscosity for each gas at temperatures up to 3000 K. The existing model for internal energy (a quadratic function of temperature) was not sufficiently accurate at these high temperatures and was replaced by a more general, fourth-order polynomial. The maximum deviation between the correlations and the underlying data was 2.2% for the specific internal energy and 7% for the specific heat capacity at constant volume. The maximum deviation in the transport properties was 4% for oxygen and carbon monoxide and 12% for carbon dioxide

[en] In this project, the free plane wave conditions were imposed on the classical SU(2) gauge field to obtain a new general Ansatz. Although afterwards it was found that this Ansatz is similar to a special case of an existing Ansatz[1], there are important dierences. The idea of this Ansatz was later applied to the other nonlinear interaction of nature, namely gravity. However, this eort encountered some complications, such as the lack of an exact definition or interpretation of energy and momentum of gravitational waves.

No abstract available

[en] The Next Generation Nuclear Plant (NGNP), a very High temperature Gas-Cooled Reactor (VHTR) concept, will provide the first demonstration of a closed-loop Brayton cycle at a commercial scale, producing a few hundred megawatts of power in the form of electricity and hydrogen. The power conversion unit (PCU) for the NGNP will take advantage of the significantly higher reactor outlet temperatures of the VHTRs to provide higher efficiencies than can be achieved with the current generation of light water reactors. Besides demonstrating a system design that can be used directly for subsequent commercial deployment, the NGNP will demonstrate key technology elements that can be used in subsequent advanced power conversion systems for other Generation IV reactors. In anticipation of the design, development and procurement of an advanced power conversion system for the NGNP, the system integration of the NGNP and hydrogen plant was initiated to identify the important design and technology options that must be considered in evaluating the performance of the proposed NGNP. As part of the system integration of the VHTRs and the hydrogen production plant, the intermediate heat exchanger is used to transfer the process heat from VHTRs to the hydrogen plant. Therefore, the design and configuration of the intermediate heat exchanger is very important. This paper will include analysis of one stage versus two stage heat exchanger design configurations and simple stress analyses of a printed circuit heat exchanger (PCHE), helical coil heat exchanger, and shell/tube heat exchanger. (authors)

[en] Photo-induced birefringence and dichroism were investigated in two kinds of poly (malonic ester) films which contain disperse red 1 (PDR1) and p-cyanozobenzene (PCN), respectively. The recording, decaying, erasing and relaxation behaviors of the birefringence and dichroism in the PDR1 could be explained by angular hole burning (AHB), angular redistribution (AR), thermal isomerization (IT), and angular diffusion (AD) effects. We suggested a simple method to determine the quantitative transition rate constants of trans-cis isomerization by using the rate equation for the conceptions of trans and cis conformers. The photo-induced birefringence was measured in decaying process in the PCN. Abnormal phenomenon, increment of the induced birefringence, was observed just after the pumping beam polarized perpendicularly to the recording beam was illuminated. We suggested a new model considering the elastic force between the side-chain and the backbone. The changes of absorbance in pumping at 365 nm and 488 nm for pumping trans-conformer and cis-conformer, respectively, were measured, and, hence, it was shown that the optical trans-cis isomerization by pumping 488 nm is very small. Nevertheless, the birefringence could be induced by the linearly polarized pumping beam at 488 nm and also 514.5 nm. The results confirmed that there is another process of photo-induced birefringence besides the trans-cis-trans photoisomerization process reported so far.

[en] Sonograms in forty two patients with tuberculous peritonitis of the wet-ascitic type were retrospectively analyzed. The ascites was clear in 24 patients (57%). There were septations, membranes and debris in 6 (14%), floating debris in 5 (12%), mobile strands or membranes in 4 (10%), and fixed septations in three(7%). Other findings were increased hepatic echogenicity, hepatosplenomegaly, pleural effusion, omental cake, thickened mesentery with adherent bowel loops, lymphadenopathy, thickening of the ileal wall, presented in order of frequency. The ultrasonographic findings are not specific for tuberculous peritonitis, but may give profitable information and protect the patient from unnecessary laparotomy

[en] We have been investigated HCPD(Hypocycloidal Pinch Device) for NUV(Near Ultraviolet) dye laser pumping source. HCPD is an useful NUV pumping source, because the spectral distribution of radiation from it has very wide range in the NUV region. For the improvement of characteristics of HCPD, we modified materials of its insulators and electrodes. Insulators were changed from PE (polyethylene) to ceramic glass, and electrodes were also changed from Brass to Mo(Molybdenum). Modified HCPD shows more enhanced characteristics. First, the lifetime of the dye cell was extended so much than as before, due to the reduction of carbon contamination and metal coating. Second, HCPD's spectral irradiance shows that it is proper pumping source for NUV laser, because its NUV intensity is higher than visible region. Characteristics of NUV dye laser pumped by HCPD was also investigated. Peak wavelengh of the dye laser observed in spectrum is 385nm and untuned spectral width of the laser is 3nm. The observed laser energy per one pulse under the optimum condition is 34.5mJ

[en] Saturated absorption signals of the 1^33Cs D₂ line are measured by changing the strength external magnetic field produced by three- axes Helmholtz coils. Both at mutually parallel state of polarization of two pump and probe beams and at mutually perpendicular state, the measured peak values of resonance of absorption signals for the cyclic transition F = 4 → F' 5 depend strongly on the external magnetic field. The peak value changes in the various external magnetic fields show the dependence of alignment collapse on the pump beam intensity and the external field strength.

[en] Laser-induced breakdown spectroscopy (LIBS) has been used to provide a rapid analysis of material compositions. A focused Nd: Glass laser beam is used to generated the plasma on the standard sample whose compositions are already known. The measurements of spatial and temporal distribution of target materials have been performed for optimization. The identification of the main elements of five metals (Zn, Al, Pb, Cu, and Fe) using the lines over a 250 A spectral range was demonstrated by the use of single laser pulse to record each spectrum. Optimum conditions of a detector are found as delayed time 620 μsec, slit which 28 μm and gate pulse width 5 μsec in the spectral range of 2900 A - 3300 A. The accuracy of the measurement is 5% for aluminum contents in the composition range of 0.1 - 5% in Zn-based alloy.