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:
Draft Revision 4 – April 2016 D. Limits the crevice and residual stresses in the tubesheet region. The extent of the tube-to-tubesheet crevice should be limited. This can be accomplished by expanding the tube throughout the tubesheet region, if practical (given other design considerations such as the desired preload in the tube for once-through steam generators). The choice of the method for expansion should consider limiting the stresses in the tube. Limiting the crevices will restrict the buildup of corrosion product and sludge that can lead to corrosion. Limiting the stresses will diminish the potential for stress-corrosion cracking. The tube-to-tubesheet weld should be designed for structural and leakage integrity under operating and design-basis accident conditions. This is generally accomplished through compliance with Section III of the ASME Code. E. Includes an appropriate allowance for deterioration (including corrosion) of the steam generator materials. This is accomplished through compliance with Section III of the ASME Code (Articles NB-2160 and NB-3121 for Class 1 components and Articles NC-2160 and NC-3121 for Class 2 components). F. Uses bolting material that will perform adequately under the expected service conditions and that is not subject to stress-corrosion cracking. This can be accomplished by following the regulatory positions in RG 1.65, “Materials and Inspections for Reactor Vessel Closure Studs.” Although RG 1.65 provides guidance for the design of reactor vessel closure studs, it is also appropriate for the selection of suitable steam generator bolting material. The integrity of bolting and threaded fasteners is also reviewed under SRP Section 3.13, “Threaded Fasteners - ASME Code Class 1, 2, and 3.” G. Uses a feedwater inlet design 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