Full Content is available to subscribers

Subscribe/Learn More  >

A Reactor Vessel Upper Head Temperature Reduction Program at South Texas Units 1 and 2

[+] Author Affiliations
David R. Forsyth, Steven C. Lindenberg, Frank Klanica

Westinghouse Electric Company, Monroeville, PA

Pat L. Strauch

Westinghouse Electric Company, Madison, PA

Ulhas Patil, Satish Dubey

South Texas Project Nuclear Operating Company, Wadsworth, TX

Paper No. PVP2005-71029, pp. 5-9; 5 pages
  • ASME 2005 Pressure Vessels and Piping Conference
  • Volume 6: Materials and Fabrication
  • Denver, Colorado, USA, July 17–21, 2005
  • Conference Sponsors: Pressure Vessels and Piping Division
  • ISBN: 0-7918-4191-X | eISBN: 0-7918-3763-7
  • Copyright © 2005 by ASME


One result of the replacement steam generator program at South Texas Units 1 and 2 was an increased core flow at the units above the desired values. In order to reduce the core flow and reduce the sensitivity of the Alloy 600 reactor vessel closure head penetrations to primary water stress corrosion cracking (PWSCC), a reactor vessel upper head temperature reduction (UHTR) program was performed at the units. The UHTR program is a field modification which results in a significant reduction in the reactor vessel head temperature by reducing the bulk fluid temperature in the upper head region of the reactor. This is accomplished by providing additional bypass flow to the upper head region from the vessel downcomer which lowers the region’s temperature. The modification, with its increased bypass flow, also reduces the core flow to acceptable levels. Lowering temperatures in the head penetrations can be an effective way to increase the time for crack initiation, reduce the rate of crack propagation and to extend the useful life of the original reactor vessel head and/or the life of a replacement head. This paper discusses the UHTR field modifications performed at South Texas Units 1 and 2, the reduction in core flow realized, the results of the modification to reduce the plant’s susceptibility to Alloy 600 head penetration cracking and the significant extension to the reactor vessel head life with the implementation of a UHTR program.

Copyright © 2005 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In