LITHIUM SILICATE (Li4SiO4)

Lithium silicate (Li4SiO4) is a candidate tritium breeding material for a D-T fusion power plant blanket.

DATA AND CORRELATIONS

The thermal and physical properties of lithium silicate are from refs [1, 2]. Correlations of the thermal and structural properties as functions of temperature are as follows:

(1)

(2)

(3)

(4)

with p the porosity and all temperatures in degrees K. These equations are valid in the temperature range of 300-1100 K. The coefficient b in Eq 2 is assumed to be the same as that for lithium oxide.

Figures 1-2 show the variation of properties with temperature and Figs 3-4 show the effect of porosity on the thermal conductivity and elastic modulus.

            TABLE 1 Thermal and structural properties of lithium silicate
  T K    [[rho]]    E GPa       [[nu]]   k W/m-K     c J/kg-K    [[sigma]]y  [[alpha]]   
         kg/m3                                                   MPa         (10-6)      
                                                                             m/m-K       
  300    2280.0     84.892               4.813       931.543                 23.780      
  350               84.127               4.408       1122.662                24.610      
  400               83.362               4.105       1272.231                25.440      
  450               82.597               3.868       1397.791                26.270      
  500               81.832               3.680       1508.310                27.100      
  550               81.067               3.525       1609.040                27.930      
  600               80.302               3.396       1703.100                28.760      
  650               79.537               3.287       1792.470                29.590      
  700               78.772               3.194       1878.433                30.420      
  750               78.007               3.113       1961.868                31.250      
  800               77.242               3.042       2043.388                32.080      
  850               76.477               2.980       2123.429                32.910      
  900               75.712               2.924       2202.312                33.740      
  950               74.947               2.874       2280.272                34.570      
 1000               74.182               2.830       2357.490                35.400      
 1050               73.417               2.789       2434.104                36.230      
 1100               72.652               2.752       2510.221                37.060      
 1150               71.887               2.719       2585.926                37.890      
 1200               71.122               2.688       2661.286                38.720      



k (W/m-K)           c (J/kg-K)

Temperature (K)

Figure 1 : Thermal conductivity and specific heat of lithium silicate.



E (GPa)         [[alpha]] (10-6 m/m-K)

Temperature (K)

Figure 2 : Elastic modulus and thermal expansion coefficient of lithium silicate.



k (W/m-K)

Temperature (K)

Figure 3 : The effect of porosity on the thermal conductivity of lithium silicate.



E (MPa)

Temperature (K)

Figure 4 : The effect of porosity on the elastic modulus of lithium silicate.



References

  1. M. Akiyama. Design Technology of Fusion Reactors, pg 459 - 474.

  2. Modelling, Analysis and Experiments for Fusion Nuclear Technology, FNT Progress Report : Modelling and Finesse. January 1987, Chapter 2.2.