Document: NUREG-0800
Document ID: 145ec0f9-012b-4669-9627-ed1b1d0cce95
Document Type: srp
Title: THERMAL AND HYDRAULIC DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070412.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.4
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CFR Title: 

Content:
subject to 10 CFR 50.34(f), paragraph 10 CFR 50.34(f)(2)(xviii). 48 Procedures for detection and recovery from conditions of ICC must be consistent with technical guidelines, including applicable EPGs developed pursuant to the TMI action plan, that incorporate response predictions based on appropriate analyses. 49 10. Thermal-hydraulic stability performance of the core during an ATWS event is such that acceptable fuel design limits are not exceeded. An acceptable method for performing such an analysis for BWR cores has been performed by GE using the TRACG code (References 16, 33, and 34).50 Technical Rationale:51 The technical rationale for application of the above acceptance criteria to the reactor core thermal and hydraulic design is discussed in the following paragraphs. 1. General Design Criterion 10 requires that the reactor core and associated coolant, control, and protection systems be designed with appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of AOOs. Proper thermal-hydraulic design of the reactor core and associated systems is necessary to assure sufficient margin exists with regard to 4.4-7 DRAFT Rev. 2 - April 1996 maintaining adequate heat transfer from the fuel to the RCS. Failure to maintain sufficient margin can result in a transition from nucleate boiling to film boiling on the fuel cladding surface. Film boiling decreases the heat transfer coefficient at the clad surface and the surface temperature rises significantly, eventually leading to fuel failure and the release of fission products to the RCS. Compliance with GDC 10 provides assurance that the integrity of the fuel and cladding will be maintained, thus preventing the potential for release of fission products during normal operation or AOOs. 2. General Design Criterion 12 requires that the reactor core and associated coolant, control, and protection systems be designed to assure that