Feasibility study for use of the natural convection shutdown heat removal test facility (NSTF) for VHTR water-cooled RCCS shutdown. (open access)

Feasibility study for use of the natural convection shutdown heat removal test facility (NSTF) for VHTR water-cooled RCCS shutdown.

In summary, a scaling analysis of a water-cooled Reactor Cavity Cooling System (RCCS) system was performed based on generic information on the RCCS design of PBMR. The analysis demonstrates that the water-cooled RCCS can be simulated at the ANL NSTF facility at a prototypic scale in the lateral direction and about half scale in the vertical direction. Because, by necessity, the scaling is based on a number of approximations, and because no analytical information is available on the performance of a reference water-cooled RCCS, the scaling analysis presented here needs to be 'validated' by analysis of the steady state and transient performance of a reference water-cooled RCCS design. The analysis of the RCCS performance by CFD and system codes presents a number of challenges including: strong 3-D effects in the cavity and the RCCS tubes; simulation of turbulence in flows characterized by natural circulation, high Rayleigh numbers and low Reynolds numbers; validity of heat transfer correlations for system codes for heat transfer in the cavity and the annulus of the RCCS tubes; the potential of nucleate boiling in the tubes; water flashing in the upper section of the RCCS return line (during limiting transient); and two-phase flow phenomena in the …
Date: August 31, 2007
Creator: Tzanos, C. P. & Farmer, M. T.
System: The UNT Digital Library
Review and assessment of nanofluid technology for transportation and other applications. (open access)

Review and assessment of nanofluid technology for transportation and other applications.

This report provides a literature review on the research and development work contributing to the current status of nanofluid technology for heat transfer applications in industrial processes. Nanofluid technology is a relatively new field, and as such, the supporting studies are not extensive. Specifically, the experimental results and theoretical predictions regarding the enhancement of the thermal conductivity and convective heat transfer of nanofluids relative to conventional heat transfer fluids were reviewed and assessments were made of the current status to derive future research and development directions for industrial applications. Pertinent parameters were considered individually as to the current state of knowledge. Experimental results from multiple research groups were cast into a consistent parameter, 'the enhancement ratio,' to facilitate comparisons of data among research groups and identification of thermal property and heat transfer trends. The current state of knowledge is presented as well as areas where the data are currently inconclusive or conflicting. Heat transfer enhancement for available nanoparticles is known to be in the 15-40% range, with a few situations resulting in orders of magnitude enhancement. The direction of future research should be to substantiate the lower range results and to continue investigations into the higher enhancements. The focus of …
Date: May 31, 2007
Creator: Yu, W.; France, D. M.; Choi, S. U. S.; Routbort, J. L. & Systems, Energy
System: The UNT Digital Library
Summary of operations and performance of the Murdock site restoration project in June 2005-December 2006. (open access)

Summary of operations and performance of the Murdock site restoration project in June 2005-December 2006.

This document summarizes the performance of the groundwater and surface water restoration systems installed by the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) at the former CCC/USDA grain storage facility in Murdock, Nebraska, during the initial period of systems operation, from June 2005 through December 2006. In the Murdock project, several innovative technologies are being used to remove carbon tetrachloride contamination from a shallow aquifer underlying the town, as well as from water naturally discharged to the surface at the headwaters of a small creek (a tributary to Pawnee Creek) north of the town (Figure 1.1). The restoration activities at Murdock are being conducted by the CCC/USDA as a non-time-critical removal action under the regulatory authority and supervision of the U.S. Environmental Protection Agency (EPA), Region VII. Argonne National Laboratory assisted the CCC/USDA by providing technical oversight for the restoration effort and facilities during this review period. Included in this report are the results of all sampling and monitoring activities performed in accord with the EPA-approved Monitoring Plan for this site (Argonne 2006), as well as additional investigative activities conducted during the review period. This document presents overviews of the treatment facilities (Section 2) and site operations …
Date: May 31, 2007
Creator: LaFreniere, L. M.
System: The UNT Digital Library
Fuel-cycle assessment of selected bioethanol production. (open access)

Fuel-cycle assessment of selected bioethanol production.

A large amount of corn stover is available in the U.S. corn belt for the potential production of cellulosic bioethanol when the production technology becomes commercially ready. In fact, because corn stover is already available, it could serve as a starting point for producing cellulosic ethanol as a transportation fuel to help reduce the nation's demand for petroleum oil. Using the data available on the collection and transportation of corn stover and on the production of cellulosic ethanol, we have added the corn stover-to-ethanol pathway in the GREET model, a fuel-cycle model developed at Argonne National Laboratory. We then analyzed the life-cycle energy use and emission impacts of corn stover-derived fuel ethanol for use as E85 in flexible fuel vehicles (FFVs). The analysis included fertilizer manufacturing, corn farming, farming machinery manufacturing, stover collection and transportation, ethanol production, ethanol transportation, and ethanol use in light-duty vehicles (LDVs). Energy consumption of petroleum oil and fossil energy, emissions of greenhouse gases (carbon dioxide [CO{sub 2}], nitrous oxide [N{sub 2}O], and methane [CH{sub 4}]), and emissions of criteria pollutants (carbon monoxide [CO], volatile organic compounds [VOCs], nitrogen oxide [NO{sub x}], sulfur oxide [SO{sub x}], and particulate matter with diameters smaller than 10 micrometers [PM{sub …
Date: January 31, 2007
Creator: Wu, M.; Wang, M.; Hong, H. & Systems, Energy
System: The UNT Digital Library