TABLE 4—Storage and Shipping Costs as Functions of Cooling Time 
Storage cost ($/gal) 
Cooling time 
(yr) 
0.5 0.006 0.02 
5 0.06 0.20 
6 0.08 0.25 
7 0.09 0.29 
10 0.13 0.41 
15 0.19 0.61 
20 0.26 0.82 
30 0.39 1.23 
Shipping cost ($/gal) 
$0.013/gal/yr $0.041/gal/yr $0.80/gal/yr 200 mi 500 mi 1,000 mi 
0.15 1.70 3.16 5.46 
1.50 0.74 1.37 2.38 
1.80 0.55 1.02 1.77 
2.10 0.49 0.91 1.58 
3.00 0.44 0.82 1.42 
4.50 0.42 0.78 1.35 
6.00 0.41 0.76 1.32 
9.00 0.40 0.74 1.29 
tivities, prior to ground disposal. The 
influence of fission-product removal on 
shipping costs will depend on which 
elements are removed and to what ex- 
tent. Since no firm flowsheet has been 
generally accepted for this step, its 
effect on waste-disposal economics is 
not considered here. 
As waste is cooled, the cost of storage 
increases, and the cost of shipping de- 
creases by virtue of having to ship less 
shield weight. The optimum cooling 
time will depend on the irradiation his- 
tory of the fuel, the cost of storage, and 
the cost of shipping. 
Storage costs. Tank storage of 
liquid wastes may be an essential step 
0.06 gal/gm U 
\ 
\ 
\ 
0.10 gal/gm U 
- Allowable, Disposol Cost ($/qal) 
O. Ol Oe On. Ua OS 
Burnup (Mwd hact/gm U 
as charged to reactor) 
FIG. 9. Allowable waste disposal cost 
for highly enriched (premium power) 
reactors—1% power cost allocated 
to disposal 
132 
Allowable Low~Acti ity Waste Disposal 
in ascheme for ultimate waste disposal. 
Storage reduces the heat generation 
and radiation problems attendant with 
shipping and subsequent processing. 
As an example, the rate of heat gener- 
ation for fuel irradiated a long time (to 
fission-product saturation) at 25 Mw/ 
ton is shown in Fig. 11 as a function of 
cooling time; 800 gal of waste per ton 
have been assumed. 
To determine an optimum storage 
time to be employed in the over-all 
storage -shipment-treatment-disposal 
cycle, an estimate of the cost of storing 
a unit volume per unit time is neces- 
sary. The following assumptions were 
made: 
900gal/ton 
1,200 gal/ton 
() “4,000 8,000 
Burnup (Mwd heat/ton) 
0 
aia : aseRine Bete} 
FIG. 10. Allowable disposal cost for 
low-activity waste—based on alloca- 
tion of 0.25% power cost to waste 
disposal 
150 
Wotts/Gol of Waste 
) 
ere 10 1090 1,000 
"Cooling Time (doys? 
FIG. 11. Waste-heat generation of 
discharged reactor fuel. Based on 
infinite irradiation time at 25 Mw/ton 
and 800 gal waste per ton 
1. Lifetime of underground storage 
tank of 50 yr 
2. Purex-type waste 
3. Tank farm operating personnel of 
2 men/shift 
Fixed charges were calculated for 
initial investments of $0.25 and $2 per 
gallon at three different annual rates: 
12% and 15% per year represent the 
range used by utility companies to 
write off investments, including profit, 
taxes, and interest on capital; 4% per 
year might be the rate for a govern- 
ment-owned burial site (2% amortiza- 
tion plus 2% average interest). 
The cost of land [($5,000/acre)/ 
(1,000,000 gal/acre) = $0.005/gal] was 
neglected compared to the initial cost of 
tankage. 
Direct operating costs (based on a 
20,000,000-gal form that has reached 
steady state) will be 
2men/shift < 4 shifts X $4500/man-yr 
20,000,000 gal 
= $0.0018/gal/yr 
Allowing for 67 % overhead, the direct 
charge will be $0.003/gal/yr. The cal- 
culated unit charges for the six cases 
are given in Table 1. 
Shielding for shipment. The num- 
ber of curies of a fission product per 
watt of reactor operating power will be 
curies _ 8.1 X 10" fiss/see/watt 
watt 3.7 X 10*° dps 
< OC er) E>) 
= 0.84 Y,(1 — 7 hito) e—dite 
where Y; = fraction fission yield, A; = 
decay constant (day—!), t) = reactor 
operating time (days), and ¢. = cooling 
time (days). 
Based on Project Separations(4) tab- 
