Document: NUREG-0800
Document ID: c372af3e-1f44-4817-b7ae-01b1c087f547
Document Type: srp
Title: STEAM GENERATOR BLOWDOWN SYSTEM (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350093.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.8
CFR Part: 
CFR Title: 

Content:
re not rendered inoperable. 10.4.8-3 Rev. 2 - July 1981 IV. EVALUATION FINDINGS CMEB verifies that sufficent information has been provided and that the review is adequate to support conclusions of the following type, to be included in the staff's safety evaluation report: The steam generator blowdown system (SGBS) controls the concentra- tion of chemical impurities and radioactive materials in the secondary coolant. The scope of review of the SGBS included piping and instru- mentation diagrams, seismic and quality group classifications, design process parameters, and instrumentation and process controls. The review has included the applicant's evaluation of the proposed system operation and the applicant's estimate of the controlling process parameters. The SGBS design meets the primary boundary material integrity require- ments of General Design Criterion 14 as it relates to maintaining accept- able secondary water chemistry control during normal operation and anticipated operational occurrences by reducing corrosion of steam generator tubes and materials thereby reducing the likelihood and magnitude of primary-to-secondary coolant leakage. The SGBS is seismic Category I and Quality Group B from its connection to the steam generator inside primary containment up to and including the first isolation valve outside containment in accordance with Regulatory Guides 1.26 and 1.29, because this portion of the SGBS is considered an extension of primary containment. The SGBS downstream of the outer containment isolation valves is not seismic Category I and meets the quality standards of Position C.1. of Regulatory Guide 1.143 since it is not safety related. Thus, the SGBS meets the quality standards requirements of General Design Criterion 1 and seismic requirements of General Design Criterion 2. Based on the foregoing evaluation, we conclude that the proposed steam generator blowdown system is acceptable. V. IMPLEMENTATION The following is intended to provide guidance to