9.8.2. Appendix 9.2: Thermodynamics and Kinetics Parameters of Fuel Constituent Redistribution Model

Diffusion constant and activation energy, heat of transport, and solubility limits for the phases present are given in Table 9.8.1, Table 9.8.2, Table 9.8.3, Table 9.8.4, respectively. Eq. (9.8-1) and Eq. (9.8-2) are used to predict the phase transition temperatures. Ref. [9-11] and [9-27] has been utilized to obtain most of the diffusion constants, diffusion activation energies and heat of transport values. Similar to Ref. [9-11] and [9-27], diffusion constants and heat of transport values are used as fitting parameters. Some of those parameters differs from the corresponding references. Phase transition Equations (Eq. (9.8-1) and Eq. (9.8-2)) are modeled as given in Ref. [9-11].

Table 9.8.1 Zirconium diffusion constant (m 2/s)

Phase

Pu < 7 at%

Pu 7 at %

α

2.0e-07

4.0e-06

δ

2.0e-07

4.0e-06

β

5.7e-06

7.0e-04

γ

0.4×105.18.05CZr+9.13C2Zr

105.18.05CZr+9.13C2Zr

Table 9.8.2 Zirconium activation energy Q0 (kJ/mol)

Phase

Pu < 7 at%

Pu 7 at %

α

170.0

170.0

δ

150.0

150.0

β

180.0

180.0

γ

128107CZr+174C2Zr

128107CZr+174C2Zr

Table 9.8.3 Qh - Heat of Transport (kJ/mol)

Phase

Pu < 7 at%

Pu 7 at %

α

0

150

δ

0

150

β

0

650

γ

-80

-200

Table 9.8.4 Zr Solubility Limit

Phase

Zr Solubility limit (at %)

α

5

δ

40

β

5

(9.8-1)Tα+δβ+γ=aPu0.164(868.15935.15)+935.15
(9.8-2)Tβ+γγ=aPu0.164(923.15965.15)+965.15