26.08.2015   An Introduction to Nuclear Materials

Radiation Swelling

Irradiation swelling is a type of dimensional instability (in the form of volume expansion) that is encountered through the formation of voids/bubbles and fission

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Figure 7.8 Radiation growth effect (length increase) in an irradiated uranium fuel specimens rolled at 600 °C as a function of fuel burnup. Adopted from Ref. [2].

 

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FUEL BURNUP (MWD/T)

Figure 7.9 The extent of swelling in various uranium-based materials as a function of fuel burnup. Taken from Ref. [2].

not in gamma-uranium, while both phases can exhibit radiation swelling even though alloying may minimize the radiation swelling effect.

Figure 7.9 shows the volume change as a function of fuel burnup for a number ofuranium-based materials. This does show the effect of alloying in suppressing radi­ation swelling. Note that the adjusted uranium shown in the plot is known as the Brit­ish Standard Fuel Produce (contains 400-1200ppm, 300-600ppmC, and small amounts ofMo, Nb, and Fe) and it shows better radiation swelling performance.

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Figure 7.10 Thermal creep and irradiation creep curves of hot rolled uranium under differently processed conditions — 1: Beta-cooled in air, 2: beta-quenched in water, 3: gamma-cooled in air, 4: gamma-quenched in water; after Ref. [2].

Irradiation Creep

Creep is an important time-dependent mechanical property for high-temperature application. In Chapter 6, we have learned how thermal creep is different from irradiation creep. So, here we are not going to repeat the fundamental principles. Figure 7.10 shows the effect of irradiation on the creep behavior of hot rolled uranium.

7.2.2