Document: NUREG-0800
Document ID: 28c03fd2-3542-41ec-bfd7-5df2087c4ee6
Document Type: srp
Title: FUEL SYSTEM DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070407.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.2
CFR Part: 
CFR Title: 

Content:
ibution Burnup distribution in the fuel Thermal conductivity of the fuel, cladding, cladding crud, and oxidation layers Densification of the fuel Thermal expansion of the fuel and cladding Fission gas production and release Solid and gaseous fission product swelling Fuel restructuring and relocation Fuel and cladding dimensional changes Fuel-to-cladding heat transfer coefficient Thermal conductivity of the gas mixture Thermal conductivity in the Knudsen domain Fuel-to-cladding contact pressure Heat capacity of the fuel and cladding Growth and creep of the cladding Rod internal gas pressure and composition Sorption of helium and other fill gases Cladding oxide and crud layer thickness Cladding-to-coolant heat transfer coefficient* Because of the strong interaction between these models, overall code behavior must be checked against data (standard problems or benchmarks) and the NRC audit codes (References. 1434 and 1535). Examples of 54 4.2-13 DRAFT Rev. 3 - April 1996 previous fuel performance code reviews are given in References 163655 through 2040 . 56 (b) Densification Effects: In addition to its effect on fuel temperatures (discussed above), densification affects (1) core power distributions (power spiking, see SRP Section 4.3), (2) the fuel linear heat generation rate (LHGR, see SRP Section 4.4), and (3) the potential for cladding collapse. Densification magnitudes for power spike and LHGR analyses are discussed in Reference 2116 and in Regulatory Guide 1.126 (Ref. 57 22) . To be acceptable, densification models should follow the guidelines 58 of Regulatory Guide 1.126. Models for cladding-collapse times must also be reviewed, and previous review examples are given in References 2341 and 2442 . 59 60 (c) Fuel Rod Bowing: Guidance for the analysis of fuel rod bowing is given in Reference 2543 . Interim methods that may be used prior to 61 compliance with this guidance are given in Reference 2644 . At this 62 writing, the causes of fuel rod bowing are not well