Very specific AGR reactor core question

[Meb15aa]

I am currently setting up a simulation for thermal hydraulic analysis of an AGR fuel bundle. However, the walls in this type of reactor, have a specific roughness that promototes turbulence which in turn provides better heat transfer characteristics. I am struggling to find data online to correctly represent the roughness height of the fuel pins. Any suggestions?

Thank you in advance

 

[Astronuc]

It's not the roughness, which is probably on the order of 0.8-1.2 microns, but rather the ribbing on the cladding outer surface.

According to the following article, the rib height is approximately 0.4 mm with a pitch of 2.75 mm. Cladding diameter ~15 mm, which may the be mean (midwall) diameter.
https://www.sciencedirect.com/science/article/pii/S2214657116300314
https://inis.iaea.org/collection/NCLCollectionStore/_Public/28/028/28028509.pdf
The article puts the pellet diameter at 14.5 mm and the cladding wall thickness at 0.38 mm.

Some additional details
https://www.researchgate.net/profile/Christophe_Gras2/publication/239358670_Post-irradiation_examination_of_a_fuel_pin_using_a_microscopic_X-ray_system_Measurement_of_carbon_deposition_and_pin_metrology/links/59e8bba4aca272bc424431ea/Post-irradiation-examination-of-a-fuel-pin-using-a-microscopic-X-ray-system-Measurement-of-carbon-deposition-and-pin-metrology.pdf

 

[Meb15aa]

Thank you for the reply I found online that the rib height is 0.11 inches which somewhat matches the second reference you provided. Thanks again