Delayed hydride cracking in Zr–2.5Nb tube with the cooling rate and the notch tip shape

Anisotropic delayed hydride cracking velocity of CANDU Zr–2.5Nb pressure tubes

“…A pre-fatigue crack of 1.7 mm was introduced using an Instron 8501 for the CT specimens to set the ratio of the pre-fatigue crack length and the specimen length or a o /W equal to 0.5, but not for the CB specimens. The CB specimens had just a sharp notch of 0.5 mm depth in the radial direction with the crack tip radius of 0.05 mm since the DHC velocity was found to be unaffected by a notch tip size smaller than 0.15 mm [12].…”

Review of the thermodynamic basis for models of delayed hydride cracking rate in zirconium alloys

“…The earliest publication in an international journal of Kim's rationale and ideas for a new DHC model appeared in [1]. Kim stated three perceived shortcomings in the predictions of the old DHC model.…”

“…This is followed by an evaluation of the physical validity of the mechanism for DHC proposed by Kim as given specifically in [4] and in other publications [1][2][3]5,6].…”

“…Over the last five years, Kim and co-workers have published a series of papers [1][2][3][4][5][6] the chief aims of which have been to promote a new model for Delayed Hydride Crack (DHC) propagation developed by Kim. The development of this new model was motivated by Kim's perception that the old model (as he called it and as we will refer to it subsequently) was incapable of predicting important aspects of the experimentally observed behaviour of DHC propagation and must have, therefore, been formulated incorrectly.…”

Hydride Reorientation and Delayed Hydride Cracking of Spent Fuel Rods in Dry Storage

“…The peak temperature was changed from 380°C to 310°C to clearly demonstrate the effect of prior creep deformation on hydride reorientation. The same stress intensity factor or K I of 18.4 MPaÖm was applied and the loading time to apply K I to the CB specimens was changed during the DHC tests, as shown in Figure 2: first, at the beginning of the thermal cycle corresponding to point A (or at room temperature); second, at the end of the hold at the peak temperature corresponding to point B; and third, after the test temperature was reached, corresponding to point C. The applied stress intensity factor, K I , was defined as such: [9,10] …”