Buoyancy-driven flow excursions in fuel assemblies Metadata

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  • Main Title Buoyancy-driven flow excursions in fuel assemblies


  • Author: Laurinat, J.E.
    Creator Type: Personal
  • Author: Paul, P.K.
    Creator Type: Personal
  • Author: Menna, J.D.
    Creator Type: Personal


  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization
    Contributor Info: USDOE, Washington, DC (United States)


  • Name: Westinghouse Savannah River Company
    Place of Publication: Aiken, South Carolina
    Additional Info: Westinghouse Savannah River Co., Aiken, SC (United States)


  • Creation: 1995-12-31


  • English


  • Content Description: A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating moderator downward through channels in cylindrical fuel tubes. Powers were limited to prevent a flow excursion from occurring in one or more of these parallel channels. During full-power operation, limits prevented a boiling flow excursion from taking place. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increases beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of historical levels.
  • Physical Description: 21 p.


  • Keyword: Heat Transfer
  • Keyword: Special Production Reactors
  • Keyword: Reactor Safety
  • Keyword: Hydraulics
  • Keyword: Reactor Cooling Systems
  • STI Subject Categories: 22 Nuclear Reactor Technology
  • Keyword: Design Basis Accidents
  • Keyword: Loss Of Coolant


  • Conference: 7. international topical meeting on nuclear reactor thermal-hydraulics (Nureth-7), Saratoga Springs, NY (United States), 10-15 Sep 1995


  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI


  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Article


  • Text


  • Other: DE95004401
  • Report No.: WSRC-MS--94-0356
  • Report No.: CONF-950904--1
  • Grant Number: AC09-89SR18035
  • Office of Scientific & Technical Information Report Number: 78713
  • Archival Resource Key: ark:/67531/metadc724038


  • Display Note: INIS; OSTI as DE95004401