Management of Commercially Generated Radioactive Waste - U.S. ...

K.18
TABLE K.1.5. Material Properties
Specific Thermal
Density Heat Conductivity
kg/m 3
Salt 2162.0 2.65 x 10 -5
Shale 2563.2
- 5
2.65 x 10
Granite 2675.0 2.65 x 10
Basalt 2883.0 2.65 x 10
Waste 2995.7 2.65 x 10
Concrete 2306.9
- 5
2.65 x 10
Backfill 2563.2
- 5
2.65 x 10
W yr/kg oC W/m °C
- 5
- 5
- 5
55
(see Table K.1.6)
(see Table K.1.6)
(see Table K.1.6)
(see Table K.1.6)
1.21
0.935
0.346
TABLE K.1.6. Thermal Conductivities W/mOC
Temperature
Shale(a)
(°C) Basalt Granite Salt (horizontal)
0 1.16 2.86 6.11 1.94
50 1.19 2.70 5.00 1.78
100 1.26 2.56 4.21 1.77
150 1.32 2.44 3.60 1.75
200 1.37 2.34 3.12 1.73
300 1.49 2.15 2.49 1.71
400 1.56 1.99 2.08 1.70
(a) Shale vertical conductivity = 0.739 x shale horizontal
conductivity.
K.1.3 Impacts of Waste Age
The thermal criteria discussed in Section K.1.1 are calculated on the basis of
10-year-old waste. Criteria estimates for waste ages of 5 to 50 years were also
developed. As spent fuel or HLW ages, the intensity of emitted radiation and heat declines
and the quantity of these materials that can be emplaced in a given repository area
increases somewhat. The thermal loading criteria required to meet the same temperature
limits tend to decline for older wastes but heat emissions decline at a faster rate
resulting overall in an increase in capacity.
Table K.1.7 lists maximum thermal loading criteria developed for both spent fuel and
HLW at 5, 10, and 50 years of age. These loadings take into account the temperature and
thermo-mechanical limitations listed in Table K.1.1.
The thermal loadings used to calculate repository capacities are shown in
Table K.1.8. These loadings take into account: 1) loading at 2/3 of calculated maximum,
2) the relationship between the near-field and far-field areas (i.e., the unused passive
areas for corridors, etc.), and 3) the limiting parameter, which is denoted by an asterisk.