Document: NUREG-0800
Document ID: 3ea2f0ac-4d7e-464a-b1c4-390c3970f642
Document Type: srp
Title: provides specific thermal-hydraulic criteria.  The available radioactive fission product
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070740002.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.4
CFR Part: 
CFR Title: 

Content:
Alternatively, Appendix K to 10 CFR Part 50 outlines the acceptable features of a conservative evaluation model to consider burst 4.2-12 Revision 3 - March 2007 strain and flow blockage. Burst strain and flow blockage models must be based on applicable data to (1) properly estimate the temperature and differential pressure at which the cladding will rupture (see item 1.B.vii above), (2) avoid underestimating the resultant degree of cladding swelling, and (3) avoid underestimating the associated reduction in assembly flow area. The flow blockage model evaluation is provided to the organization responsible for the review of transient and accident analyses for incorporation in the comprehensive ECCS evaluation model to demonstrate that the criteria in 10 CFR 50.46(b) are not exceeded. The reviewer also determines whether the analysis of AOOs and other accidents should include fuel rod ballooning. The possibility of ballooning during an AOO transient or accident increases as the fuel rod pressure exceeds the system pressure. Those non-LOCA accidents that result in clad ballooning should examine the possibility of DNB propagation resulting from ballooning. The impact of ballooning on non-LOCA accidents should not be underestimated. A limit on ballooning (circumferential strain) may be required to prevent DNB propagation for these accidents. v. Structural Deformation. Appendix A discusses the applicable analytical procedures. 2. Description and Design Drawings The reviewer determines that the fuel system description and design drawings provide an accurate representation and supply the information needed in audit evaluations. Completeness is a matter of judgment, but the following fuel system information and associated tolerances are necessary for an acceptable fuel system description: • Type and metallurgical state of the cladding • Cladding outside diameter • Cladding inside diameter • Cladding inside roughness • Pellet outside diameter • Pellet roughness