22.08.2015   Comprehensive nuclear materials

Gibbs Free Energy of Formation

Some data on the Gibbs free energy of formation for actinide nitrides exist. In this section, the Gibbs free energy of formation of uranium nitride, UN, pluto­nium nitride, PuN, uranium and plutonium mixed nitride, (U, Pu)N, neptunium nitride, NpN, and americium nitride, AmN are summarized.

Table 4

The standard thermodynamic functions of UN

T(K)

Cp(Jmor»K-‘)

H-H298 (Jmol-1)

S(Jmol-1K-1)

-(G-H298)/T (Jmol-1 K-1)

AG (Jmol-1)

298

47.95

0

62.68

62.68

-270978

300

48.04

96

63.00

62.68

-270812

400

51.49

5089

77.34

64.62

-262 582

500

53.64

10 352

89.08

68.37

-254530

600

55.27

15 801

99.01

72.67

-246614

700

56.63

21 397

107.63

77.06

-238 788

800

57.84

27121

115.27

81.37

-231 011

900

58.98

32 963

122.15

85.53

-223235

1000

60.06

38915

128.42

89.51

-215 267

1100

61.12

44 975

134.19

93.31

-206948

1200

62.18

51 140

139.56

96.94

-198457

1300

63.28

57 413

144.57

100.41

-190019

1400

64.47

63 799

149.28

103.71

-181 626

1500

65.81

70312

153.74

106.87

-172640

1600

67.38

76969

157.98

109.87

-163550

1700

69.27

83 798

162.01

112.72

-154384

1800

71.59

90837

165.87

115.41

-145111

1900

74.40

98132

169.58

117.93

-135 687

2000

77.81

105738

173.14

120.28

-126062

2100

81.86

113716

176.58

122.43

-116178

2200

86.62

122133

179.90

124.39

-105 969

2300

92.11

131 063

183.12

126.14

-95 367

2400

98.35

140580

186.24

127.67

-84302

2500

105.33

150757

189.28

128.98

-72 701

2600

113.04

161 669

192.23

130.05

-60489

2628

115.32

164866

193.04

130.31

-56954

The values of AfG for UN were calculated from the values of AH2g8 and thermal functions for uranium and nitrogen.

Source: Hayes, S. L.; Thomas, J. K.; Peddicord, K. L. J. Nucl. Mater. 1990, 171,300-318; Matsui, T.; Ohse, R. W. High Temp. High Press. 1987, 19, 1-17; Cordfunke, E. H. P.; Konings, R. J. M.; Potter, P. E.; Prins, G.; Rand, M. H. Thermochemical Data for Reactor Materials and Fission Products; Elsevier: Amsterdam, 1990; p 667; Chase, M. W.; Curnutt, J. L.; Prophet, H. JANAF Thermochemical Tables; Dow Chemical Co.: Midland, MA, 1965.