Tests on Models of Nuclear Reactor Elements - Studies of Diffusion

PDF Version Also Available for Download.

Description

To estimate the distribution of temperature in the proposed nuclear reactor, one must determine a coefficient of eddy diffusivity and devise a suitable method of computing the heat transfer. Measurements of diffusion in a model of a blanket element for the proposed reactor indicated a gross eddy diffusion coefficient of about 0.002 (? .0005) ft{sup 2}/sec. Thus, the apparent eddy diffusion for the test conditions is about 200 times the molecular diffusivity of water and about. twice that of the liquid sodium. Even approximate methods of applying this result require an elaborate calculation if the primary characteristics of the flow ... continued below

Creation Information

McNown, J. S.; Yih, C. S.; Yagle, R. A.; O&#x27 & Dell, W. W. March 1, 1957.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Publisher

  • Savannah River Site (S.C.)
    Publisher Info: SRS (Savannah River Site (SRS), Aiken, SC (United States))
    Place of Publication: Aiken, South Carolina

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

To estimate the distribution of temperature in the proposed nuclear reactor, one must determine a coefficient of eddy diffusivity and devise a suitable method of computing the heat transfer. Measurements of diffusion in a model of a blanket element for the proposed reactor indicated a gross eddy diffusion coefficient of about 0.002 (? .0005) ft{sup 2}/sec. Thus, the apparent eddy diffusion for the test conditions is about 200 times the molecular diffusivity of water and about. twice that of the liquid sodium. Even approximate methods of applying this result require an elaborate calculation if the primary characteristics of the flow system are to be taken into account. The dispersion of dye in flowing water provided an indication of the diffusion in the model tests. The presence and arrangement of the rods, the effect on the flow?of the spiral wire spacers, and the existence of a comparatively large area on which a laminar sub-layer develops made it impossible to get simple turbulence criteria like those obtained downstream from a screen. Although the results are consequently somewhat unsystematic, they do establish reliably the approximate magnitude of the coefficient of eddy diffusivity. The data were obtained from both line and sectional traverses, the two results being approximately equal. Preliminary data were also obtained for a core element for which {epsilon} ~ 0.003, only slightly less than for the blanket element. Determination of the diffusion coefficient makes it possible to compute the temperature for an array of spatially variable heat sources, as occur in any element. Because of the extreme complexity of the problem, two alternative simplifying assumptions are proposed., In one, the heat sources are assumed to be concentrated along their axes. In the other, the heat is assumed to pass to the fluid immediately at the surface of each circular rod and then to diffuse as though no other rods were present. In each case the effect of the rods on the pattern of diffusion is taken into account only by the afore-mentioned ratio between the local and the apparent diffusivities. The calculations involve a doubly infinite summation to account for the rods and for the so\id walls of the container which are assumed to be insulated. An effect of the rods is to make the local diffusivity much more than the apparent diffusivity, which was observed. In a calculation based on an analogy with heat transfer, the former was found to be 5.3 times the latter.

Subjects

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Report No.: AECU-3757-PT2
  • Grant Number: none
  • Office of Scientific & Technical Information Report Number: 1062727
  • Archival Resource Key: ark:/67531/metadc840179

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • March 1, 1957

Added to The UNT Digital Library

  • May 19, 2016, 9:45 a.m.

Description Last Updated

  • Dec. 2, 2016, 3:21 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 2

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

McNown, J. S.; Yih, C. S.; Yagle, R. A.; O&#x27 & Dell, W. W. Tests on Models of Nuclear Reactor Elements - Studies of Diffusion, report, March 1, 1957; Aiken, South Carolina. (digital.library.unt.edu/ark:/67531/metadc840179/: accessed October 17, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.