(curies per |ic/ml) was 10^ or greater. Slightly less than four dis- 

 charges per month could be made without undue risk for this ratio 

 equal to 10^ curies per lic/ml. 



These data are presented in graphical form in Figure Z, from 

 which the values of the ratio M/spp^ f or N equal to one per month, one 

 per day, and 10 per day have been obtained. Using these ratios, the 

 maximum permissible activities which can be discharged in any single 

 release in this "typical" harbor for the various important isotopes, 

 listed in Tables 3 and 5 for the primary coolant of the SAVANNAH and 

 the NAUTILUS, have been calculated for these three rates of discharge. 

 The results are presented in Table 8. 



This computation applies to the hypothetical case in which the 

 discharge is composed of only a single isotope. For the actual situation 

 the additive effect of the combination of isotopes present must be con- 

 sidered. Assuming that the relative composition of the isotopes in the 

 primary coolant remains fairly constant (a condition which has been 

 shown to exist for the NAUTILUS), then the weighted mean ppc value 

 for the isotope mix may be utilized in computing a permissible gross 

 activity, which can be compared to the gross activity in the actual dis- 

 charge resulting from the listed isotopes. This has been done for the 

 isotope mix in the primary coolant for both the SAVANNAH and the 

 NAUTILUS. 



A comparison of the permissible activities given in Table 8 with 

 the activities which have been predicted to exist in the warm-up volume 

 discharge from the SAVANNAH, as given in Table 3, indicates that the 

 predicted gross activity due to the listed isotopes exceeds the computed 

 permissible activity even for only a single release per month. Also the 

 predicted activity for Co 60 and Ta 182 both exceed the computed per- 

 missible activities for these individual isotopes. It would thus appear 

 undesirable to have a general operating doctrine which would allow 

 liquid effluents of the volume and activity predicted for the warm-up 

 volunne of primary coolant from the SAVANNAH to be discharged into 

 harbors and estuaries. It should again be pointed out that the basis of 

 this conclusion involves the most conservative (safe) assumptions re- 

 garding the eating habits of a selected segment of the population, and 

 also regarding biological uptake of the radioisotopes. Such assumptions 

 are not unduly conservative for a country such as Japan, where the bulk 

 of the protein requirement is supplied from seafood. The assumptions 

 may well be overly conservative for the coast of the United States. 

 However, recommendations on general operating doctrine for nuclear- 

 powered raerchant ships must envision these ships operating in areas 

 in which the most restrictive conditions as to waste discharge would 

 apply. 



A comparison of the figures in Table 8 with the average measured 

 activities in the primary coolant expansion volumes for the NAUTILUS 

 as given in Table 5 suggests quite a different conclusion. The observed 

 activities for each isotope, as well as the computed gross activity as- 

 suming an isotope mix with the observed activities for the listed isotopes, 



36 



