In-Reactor Measurement of Cladding Strain: Fuel Density and Relocation Effects

A conceptual model for the fuel oxidation of defective fuel

“…(44) to be comparable to that of the gap (i.e., V crack $ 3V gap ). Moreover, the CANDU fuel design also has thin sheathing that can accommodate expansion from fuel cracking and relocation, i.e., the In-Reactor Diameter Measuring Rig (IRDMR) has been used for a direct in-reactor measurement of CAN-DU fuel relocation, where a diametral relocation of approximately 30 lm was observed [71]. Hence, the simple crack model appears to be consistent with the observed in-reactor behaviour.…”

Overview of high-temperature fuel behaviour with relevance to CANDU fuel

“…These measurements illustrate pellet expansion due to relocation as well as compliance of the fuel fragments on contact with the sheath at full power [108]. Indirect evidence, from gas release measurements and UO 2 restructuring on fuel fabricated with diametral clearances typical of CANDU fuel, indicate that the fuel and sheath achieve at least light contact during operation (i.e.…”