TABLE Ill 
PERCENTAGES OF INITIAL ACTIVITY REMAINING AFTER TEN YEAR CON- 
TAINMENT AND MAXIMUM PERMISSIBLE CONCENTRATIONS FOR DRINKING 
WATER, FOR SELECTED FISSION PRODUCT ELEMENTS AND ORNL 
ISOTOPES 
Percent after MPC (3) Percent after MPC (3) 
Isotope 10 years 10 years (c/ml) 
MPC for mixtures of isotopes of unknown composition is 10°” Uc/ml. 
beyond the life of the steel drum. On the other hand, experiments de- 
signed to test the effect of hydrostatic pressure on disposal containers, 
indicated that voids in concrete may, at depths of a few hundred toa 
thousand meters, permit implosion of the steel drum and fracture of 
the concrete, thereby bringing about premature release of contaminant 
to the sea. 
The tests of canisters which have been performed have been con- 
cerned with disposal into at least 1000 fathoms of water where pressures 
in excess of 3000 pounds per square inch will be encountered, whereas 
we are concerned here with water depths up to approximately 30 fathoms 
where pressure less than 100 pounds per square inch will be encoun- 
tered. Although there is some doubt as to whether presently used con- 
tainers remain intact after disposal to the sea bottom, proper design 
and testing can provide the necessary information. 
I'S) 
