There is no way that man can directly influence the processes 

 of advection. turbulent diffusion, and concentration in a given environ- 

 ment. Man can, however, influence the degree of initial mechanical 

 dilution through proper design of the discharge assembly. Since the 

 rate of dispersion through turbulent processes is scale dependent, man 

 can then influence indirectly the natural diffusion of the wastes by in- 

 creasing the degree of initial mechanical dilution. Also, initial me- 

 chanical dilution reduces the density difference between effluent and 

 receiving waters, and hence aids diffusion. Considering the volumes 

 of liquid effluent involved (a maximum of approximately 300 ft^), the 

 incorporation of a discharge assembly capable of supplying an initial 

 mechanical dilution of 100:1 should be no problem. 



Factors such as current velocity, depth, density stratification, 

 wind velocity and fetch, and density difference between effluent and 

 receiving waters all influence the process of turbulent diffusion. Since 

 these factors differ so markedly from one harbor environment to an- 

 other, it is virtually impossible to make any precise general statement 

 regarding the subsequent fate of liquid wastes discharged into harbor 

 environments. The degree to which harbors, harbor approaches and 

 other inshore environments might be utilized as receivers of liquid 

 radioactive effluent from nuclear-powered ships must ultimately be 

 determined through an evaluation of each specific location involved. 



We can, however, consider the general characteristics of certain 

 types of harbors, with the purpose of determining ■whether there is any 

 possibility of utilization of any considerable fraction of the harbor en- 

 vironments as receivers of liquid effluent from nuclear ships. Thus 

 some important world harbors are approached through locks which 

 limit exchange with the open coastal waters. In most cases such har- 

 bors contain fresh water or water of very low salinity. The absence 

 of tidal currents limits the turbulent diffusion within such harbors, 

 and the lack of free exchange with the open coastal waters would result 

 in accumulation within the harbor of a.ny waste disposed therein. It 

 therefore appears unlikely that harbors located in tideless basins, 

 connected to the sea by a system of locks, can be utilized as receivers 

 of any effluent from nuclear-powered ships. 



Another group of harbors are located well up estuaries of major 

 river systems, and are characterized by fresh water, though tidal cur- 

 rents of significant magnitude may occur. Possible restriction on the 

 use of such harbors as potential receivers of liquid effluent from nu- 

 clear ships is not so much due to the lack of a mechanism (such as 

 tidal currents) to induce appreciable turbulent diffusion within the har- 

 bor, but rather due to the much larger concentration factors to the 

 biota which occur in fresh water as compared to sea water. 



The majority of harbors throughout the world are, however, lo- 

 cated in the lower reaches of tidal estuaries or in coastal embayments. 

 The waters of these harbors are normally characterized by salinities 

 of from one-quarter to three-quarters that of full sea water; they are 

 influenced to some degree by tidal currents and wind induced motion; 



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