Document: NUREG-0800
Document ID: 422f3de0-8599-4095-ba95-7882c43c82b9
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:
rt 50. 6. Provisions for Accessing the Secondary Side of the Steam Generator Corrosion products (including deposits and sludge) and other contaminants can accumulate in the secondary side of the steam generator. For example, corrosion products and contaminants have been observed along the length of the steam generator tubes, in the crevice between the tube and the tube supports, and at the top of the tubesheet. Depending on the nature of these corrosion products and contaminants, degradation of the tubes (or other components) can occur. Because this degradation could lead to degradation of the RCPB or SSPB, the design of the steam generator should provide access for the removal of these corrosion products and contaminants. These provisions will supplement the removal of corrosion products and contaminants by blowdown, which is reviewed under SRP Section 10.4.8. In addition to corrosion products and other contaminants, foreign objects (including loose parts) can be introduced into the steam generator. These objects can also lead to degradation of the RCPB or SSPB; therefore, the design of the steam generator should provide access for removing these objects. The steam generator design is considered acceptable from a secondary-side access standpoint if it provides adequate access to the internals so that tools may be inserted to inspect and remove (1) corrosion products and contaminants (such as those found on the tubesheet and at the tube-to-tube support crevice) that may lead to corrosion and (2) foreign objects (including loose parts) that may affect tube integrity. 5.4.2.1-14 Draft Revision 4 – April 2016 These provisions, in conjunction with appropriately performed inservice inspections, as discussed above, provide assurance that (1) the probability of abnormal leakage, rapidly propagating failure, and gross rupture is extremely low and (2) the RCPB design conditions are not exceeded during any condition of normal operation, including anticipated operational