PSI - Issue 60

P.A. Jadhav et al. / Procedia Structural Integrity 60 (2024) 631–654 P. A. Jadhav et.al. / Structural Integrity Procedia 00 (2019) 000 – 000

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The equation for these two curves which are listed in CSA standard is given in eq. 1 and eq. 2 respectively. The curve corresponding to these equations is shown in the Fig. 3 and Fig. 4. According to IAEA-TECDOC-1410 (2004) the reason for this hysteresis is the internal stresses in the solid system developed during precipitation and dissolution of hydride caused by the 17% volume change associated with transformation of alpha zirconium matrix into delta hydride.

(1)

34500

  

  



4 8.19 10 exp

TSSD

 

RT





8.314

R

J K mol 



(2)

28000

  

  



4 4.11 10 exp TSSP  

RT

100.0 120.0 140.0 160.0 180.0 200.0

TSSP TSSD

0.0 20.0 40.0 60.0 80.0

H concentration in ppm

0

50 100 150 200 250 300 350

T in deg. C

Fig. 3. Solubility of hydrogen in Zr-2.5Nb as a function of temperature given by CSA Standard (2016)

If we take the logarithmic form of the equation, the plot given in fig. 4 is obtained.