Document: NUREG-0800
Document ID: dad439b8-1bb4-47e8-8a90-65cbee6cc2b2
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1602/ML16029A367.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.2.1
CFR Part: 
CFR Title: 

Content:
that prevents flow-accelerated corrosion (FAC), water hammer, and thermal stratification. The reviewer determines that the feedwater components in the steam generator are resistant to FAC because they are fabricated from chromium-containing low alloy steel or stainless steel. (SRP Section 10.3.6, “Steam and Feedwater System Materials,” provides detailed guidance on materials selection to avoid FAC.) The potential for water hammer can be minimized by following the guidance in Branch Technical Position (BTP) 10-2, “Design Guidelines for Avoiding Water Hammers in Steam Generators,” (NUREG-0800, Chapter 10). Examples of design features that prevent water hammer in feedring designs include top-discharge feedring tubes, a leak-limiting feedring seal assembly, and leak-tight feedring inspection port covers. Operating experience has shown that thermal stratification in the feedwater inlet nozzle can be prevented by using an elevated feedring design or “gooseneck” inlet design that forces incoming feedwater to fill the inlet nozzle. The above criteria, in conjunction with the acceptance criteria for interfacing reviews and appropriately performed inservice inspections, as discussed above, provide assurance that (1) the design is compatible with environmental conditions during normal operating, testing, maintenance, and postulated accident conditions, (2) the probability of abnormal leakage, rapidly propagating failure, and gross rupture will be extremely low, (3) the design conditions of the RCPB are not exceeded during operation, and (4) sufficient margin is available to prevent rapidly propagating failure, consistent with the requirements of GDC 4, 14, 15, and 31. 5.4.2.1-10 Draft Revision 4 – April 2016 3. Fabrication and Processing of Ferritic Materials A. Fracture Toughness The steam generator is part of the primary and secondary system pressure boundaries. As a result, the materials selected should be sufficient to avoid rapidly propagating failure and to