Document: NUREG-0800
Document ID: 2779d8da-7e49-4277-9495-bf9ec444636f
Document Type: srp
Title: STEAM GENERATOR BLOWDOWN SYSTEM (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070602.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.8
CFR Part: 
CFR Title: 

Content:
ll be maintained. The steam generator tubes are part of the reactor coolant pressure boundary, and these tubes could be degraded by adverse chemistry conditions on the secondary site. The SGBS primary function is to remove steam generator secondary-side impurities and thus assist in maintaining acceptable secondary-side water chemistry in the steam generators. Specific criteria necessary to meet the relevant requirements of GDC General Design Criteria31 1, 2, and 14 are as follows: 1. The SGBS is sized to accommodate the design blowdown flow needed to maintain secondary coolant chemistry for normal operation, including anticipated operational occurrences. 2. Equipment capacities are based on design blowdown flow rates and are such that temperature limits for heat-sensitive processes are not exceeded. 3. Instrumentation and automatic controls ensure operation within design parameters. 4. The design of 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. The design of the SGBS downstream of the outer DRAFT Rev. 3 - April 1996 10.4.8-4 containment isolation valves is in accord accordance with the provisions of Regulatory 32 Guide 1.143, Position C.1.1. Technical Rationale The technical rationale for application of these acceptance criteria to reviewing the steam generator blowdown system is discussed in the following paragraphs:33 1. GDC 1 requires that structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. The criterion further requires that quality standards be evaluated and that a quality assurance program be established to document compliance with quality requirements. GDC 1 applies to this section because portions of the steam generator blowdown system constitute part of the reactor