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Title: Leak-before-break analysis of Type 304 stainless steel piping

Conference ·
OSTI ID:5960909

The nuclear materials production reactors at the Savannah River Plant (SRP) were designed and built in the 1950's and have operated successfully since that time. Unlike commercial power reactors, the production reactors are moderated and cooled by heavy water and are operated at moderately low temperatures and internal pressures. In addition, the entire primary coolant pressure boundary is constructed of Type 304 stainless steel or its cast equivalent, CF-8, except for seals, gaskets and other serviceable parts. Due to the low applied stresses coupled with high toughness, the primary coolant piping is highly tolerant of defects. In the operational history of the plant, several instances of minor leakage from stress corrosion cracks have occurred in the piping, thus exemplifying a Leak-Before-Break (LBB) capacity of the system. Fundamentally, LBB capability provides the assurance that a postulated through-wall crack could be detected by the resulting leakage before the onset of crack instability and the ensuing pipe failure. The Leak-Before-Break demonstration of the SRP primary coolant piping has been formalized through a detailed fracture assessment of postulated flaws in piping with the result that the through-wall crack length at instability conditions is well in excess of the crack length corresponding to the minimum detectable leak rate of the primary coolant system. Additional elements supporting the demonstration of SRP piping integrity include the in-service inspection program and the moderator leak detection system. The extent, frequency and method of non-destructive inspection for SRP piping conforms in general with Section XI of the ASME code and NUREG-0313 requirements for commercial Boiling Water Reactors.

Research Organization:
Du Pont de Nemours (E.I.) and Co., Aiken, SC (United States). Savannah River Lab.
DOE Contract Number:
AC09-76SR00001
OSTI ID:
5960909
Report Number(s):
DP-MS-88-146; CONF-890855-20; ON: DE89010460
Resource Relation:
Conference: 10. international conference on Structural Mechanics in Reactor Technology (SMIRT), Anaheim, CA, USA, 14-18 Aug 1989; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English