Document: NUREG-0800
Document ID: a04e4cfb-c559-4bf7-8a78-c1394c7838ad
Document Type: srp
Title: MAIN CONDENSER EVACUATION SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070510078.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.2
CFR Part: 
CFR Title: 

Content:
ng the following: A. If there is a potential for explosive mixtures to exist, the MCES is designed to withstand the effects of an explosion and instrumentation is provided to detect and annunciate the buildup of potentially explosive mixtures, dual instrumentation is provided to detect, annunciate, and effect control measures to prevent the buildup of potentially explosive mixtures, as outlined in SRP Section 11.3, subsection II, "Acceptance Criteria," SRP Acceptance Criteria, Item 6. Such a potential does not exist on systems designed to maintain the steam content above 58% by volume in hydrogen-air mixtures or nitrogen content above 92% by volume in hydrogen-oxygen mixtures in all MCES components. The design pressure and normal operational absolute pressure should be provided for MCES components containing potentially explosive mixtures. Technical Rationale The technical rationale for application of these acceptance criteria to the areas of review addressed by this SRP section is discussed in the following paragraphs: 1. Compliance with GDC 60 requires that provisions be included in the nuclear power unit design to control suitably the release of radioactive materials in gaseous and liquid effluents during normal operation, including anticipated operational occurrences. GDC 60 is applicable to the design of the MCES because radioactive materials in both gaseous and liquid form are routinely processed in this system in BWRs during normal operation. In PWRs, radioactive materials are processed in this system only if there is a primary-to-secondary steam generator tube leak. Design features are incorporated into the system to ensure that these radioactive materials are controlled and routed appropriately. 10.4.2-4 Revision 3 - March 2007 2. Meeting these requirements provides assurance that the release of radioactive materials in gaseous and liquid effluents from the MCES during normal operation, including anticipated operational occurrences, is kept as low as is