[en] Small scale experiments involving water flows are used to provide mean flow and turbulence field data for LMFBR outlet plenum flows. Measurements are performed at Reynolds Number (Re) values of 33000 and 70000 in a 1/15-scale FFTF geometry and at Re = 35000 in a 3/80-scale CRBR geometry. The experimental behavior is predicted using two different turbulence model computer programs, TEACH-T and VARR-II. It is found that the qualitative nature of the flow field within the plenum depends strongly upon the distribution of the mean inlet velocity field, upon the degree of inlet turbulence, and upon the turbulence momentum exchange model used in the calculations. It is found in the FFTF geometry that the TEACH-T predictions are better than that of VARR-II, and in the CRBR geometry neither code provides a good prediction of the observed behavior. From the sensitivity analysis, it is found that the production and dissipation of turbulence are the dominant terms in the transport equations for turbulent kinetic energy and turbulent energy dissipation rate, and the diffusion terms are relatively small. From the same study a new set of empirical constants for the turbulence model is evolved for the prediction of plenum flows

No abstract available

[en] Small scale experiments involving water flows are used to provide mean flow and turbulence field data for LMFBR outlet plenum flows. Measurements are performed at Reynolds number (Re) values of 33000 and 70000 in a 1/15 - scale FFTF geometry and at Re = 35000 in a 3/80-scale CRBR geometry. The experimental behavior is predicted using two different two-equation turbulence model computer programs, TEACH-T and VARR-II. It is found that the qualitative nature of the flow field within the plenum depends strongly upon the distribution of the mean inlet flow field, importantly also upon the degree of inlet turbulence, and also upon the turbulent momentum exchange model used in the calculations. In the FFTF geometry, the TEACH-T predictions agree well with the experiments. 7 refs

[en] The objective of this project is to develop an on-line computerized system that can do turbine cycle performance monitoring and analysis during normal operation and recommend remedial measures after finding thermal efficiency degradation or a missing megawatt problem. The system takes plant instrument data through a central computer to calculate performance indices and to timely present the operating performance information and diagnostic messages of each component in the turbine cycle. It is designed to have the following features: (1) to provide in real time the plant heat rate and the important performance information of each component required for plant thermal performance evaluation; (2) to identify the possible causes of plant efficiency degradation; and (3) to present all the important information on a color graphics terminal by simply pressing a few buttons

[en] A complete evaluation of the EPRI-1 correlation on the predictions of the first critical heat fluxes (CHFs), the higher rank CHFs and the CHFs of three fuel element abnormalities for PWR applications was performed using COBRAIIIC/MIT-1 code. In addition to the evaluation, the EPRI-1 correlation was also modified by adding two correction factors, a quality correction factor and a cold wall correction factor, to improve its accuracy

[en] Due to the very limited indigenous energy resources, Taiwan has to import over 95% of the energy from overseas to meet her need. In this paper, the supply and demand of various kind of major energies will be discussed. Also, in order to lessen the environmental burden and increase the energy independence for Taiwan, the so-called quasi-indigenous energy - nuclear energy, will play an important role in Taiwan's future energy mix. The optimal ratios of the mix in the year of 2005 in Taiwan area using multiobjective method by independent research Institute will also be discussed. (author)

No abstract available

[en] The purpose of the study is to use extended axial nonuniform, rod-bundle critical heat flux (CHF) data points, which were released by the Heat Transfer Research Facility (HTRF) of Columbia University, to perform a statistical analysis of five publicly available CHF correlations and determine if there any way to refine these correlations. This study evaluates the performance of five CHF correlations with the COBRA IIIC/ MIT-1 thermal-hydraulic subchannel analysis code. The five correlations include the three major vendors' correlations: CE-1, BandWnumber2 and W-3. The other two correlations are more generalized and span large operating ranges, including both PWR and BWR conditions. These are Bowring's WSC-2 correlation and the EPRI-1 correlation developed at Columbia University under EPRI sponsorship). The data these correlations were evaluated against comprised a group of 1635 axial nonuniform, rod-bundle, first CHF points for PWR core geometries, spanning the pressure range of 5.14 to 17 MPa (745 to 2465 psia), the mass velocity range of 698 to 5484 kg/m²-sec (0.5145 to 4.043 Mlb/ft²-hr) and the CHF local quality range of -0.2461 to 0.6979. In the evaluations, the correlations were applied to the entire CHF points, and also applied to the points within their respective ranges. The results of this study show that all five CHF correlations can give resonable predictions when used with the COBRA IIIC/MIT-1 code based on the CHF points within their respective ranges

[en] A good thermoelectric material should have a high Seebeck coefficient, a low electrical resistivity, and a low thermal conductivity. For conventional thermoelectric materials, however, increasing the Seebeck coefficient also leads to a simultaneous increase in the electrical resistivity. In this paper, a method of layer-by-layer deposition of MnSi_1.7 film with high Seebeck coefficient and low electrical resistivity is developed. After deposition of the first MnSi_1.7 sub-layer, the deposition process is interrupted for several minutes, and then continues for another MnSi_1.7 sub-layer. Therefore, the MnSi_1.7 film contains two sub-layers for one interruption, three sub-layers for two interruptions, and so on. It is found that the n-type MnSi_1.7 film with two sub-layers has a higher Seebeck coefficient, −0.451 mV K⁻¹, and a lower electrical resistivity, 19.4 mOhm-cm, at 483 K as compared to that of without deposition interruption, −0.152 mV K⁻¹ and 44.3 mOhm-cm. The p-type MnSi_1.7 film with three sub-layers also has a higher Seebeck coefficient, 0.238 mV K⁻¹, and a lower electrical resistivity, 5.5 mOhm-cm, at 733 K in comparison with that of without deposition interruption, 0.212 mV K⁻¹ and 10.4 mOhm-cm. - Highlights: • MnSi_1.7 films are deposited layer by layer by a short time interruption of film deposition. • The thickness of each MnSi_1.7 layer can be controlled in the nano-scale. • MnSi_1.7 films have a higher Seebeck coefficient and a lower electrical resistivity. • The quantum size effect in n-type MnSi_1.7 films is rather strong

[en] In the wake of Japan's Fukushima Daiichi Nuclear Power Plants event, the Atomic Energy Council (AEC) has asked Taiwan's Nuclear Power Plant operator (TPC) to re-examine and re-evaluate the vulnerabilities of its nuclear units, and furthermore, take possible countermeasures against extreme natural disasters, including earthquake, tsunami and rock-and-mud slide. The evaluation process should be based on both within and beyond Design Basis Accidents, by reference to the actions recommended by the world nuclear authorities and groups, namely, IAEA, USNRC, NEI, ENSREG and WANO. Taiwan is a very densely populated region of the world. Furthermore, like Japan, due to its geophysical position, Taiwan is prone to large scale earthquakes, and although historically rare, Taiwan also faces the potential risk of tsunamis. AEC also asked TPC to perform the stress test following the specification given by WENRA (later ENSREG) and conducted in all the EU's nuclear reactors. After completion of the stress test for all the nuclear power plants, AEC was trying to have the reports peer reviewed by international organizations, as EU did. The OECD/NEA accepted AEC's request and formed a review team specific to the review of Taiwan's National Report for the Stress Test. There were 18 follow-up items after the NEA's review. Based on these items, AEC developed five orders to require TPC further enhancing their capabilities to cope with extreme natural hazards. The ENSREG also formed a nine-expert review team for Taiwan's Stress Test in response to AEC's request almost at the same time as the OECD/NEA. The ENSREG review team began their works in June 2013 by desktop review, and ended in early October 2013 by country visit to Taiwan. While the assessment of post-Fukushima evaluation reveals neither immediate nuclear safety concerns nor threats to the public health and safety, AEC requested that TPC focus on strengthening its re-evaluation on design basis against earthquakes, tsunamis and heavy rainfalls, and enhancing its capability to mitigate a prolonged station blackout (SBO) for further improvement. However, these improvements are justified on the basis of the fact that the risk to be hit by extreme natural hazards, such as earthquakes, flooding including tsunamis, extreme weather conditions and volcanism, is much higher in Taiwan than in many other geographical environments of the world. (author)