Considerations on the Disposal of Radioactive Wastes From Nuclear-Powered Ships Into the Marine Environment (1959)

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The map on the front cover is reproduced from a bath/metric chart of fhe North Atlantic Basin published in "Instructions and Sailing Directions to Accompany fhe Wind and Currenf Charts" 7th Edition of 1855, The chart was compiled by Lieu- tenant Matthew Fontain Maury when he was Superintendent of the U.S. Naval Observatory and Hydrographic Office. The cooperation of the U.S. Navy Hydro' graphic Office in making this chart available is gratefully acknowledged.

Considerations on the Disposal of Radioactive Wastes from Nuclear'Powered Ships into The Marine Environment A report of the Committee on the Effects of Atomic Radiation on Oceanography and Fisheries of the National Academy of Sciences' Study of the Biological Effects of Atomic Radiation Publication 658 National Academy of Sciences—National Research Council Washington, D.C. 1959

Library of Congress catalog card number: 59'60054

COMMITTEE ON THE EFFECTS OF ATOMIC RADIATION ON OCEANOGRAPHY AND FISHERIES Roger Revelle, Chairman, Scripps Institution of Oceanography Howard Boroughs John H. Harley Hawaii Marine Laboratory U. S. Atomic Energy Commission Dayton E. Carritt Bostwick Ketchum The Johns Hopkins University Woods Hole Oceanographic Institution Walter A. Chipman Louis A. Krumholz U. S. Fish and Wildlife Service University of Louisville Lauren R. Donaldson Charles E. Renn University of Washington The Johns Hopkins University o • ' _j T T . Milner B. Schaeffer Ricnard F Foster Inter-American Tropical General Electric Company Tuna Commission Edward D. Goldberg Allyn C. Vine Scripps Institution of Oceanography Woods Hole Oceanographic Institution Richard H. Fleming Lionel A. Walford University of Washington U. S. Fish and Wildlife Service Warren S. Wooster Scripps Institution of Oceanography Working Group on Disposal of Radioactive Wastes from Nuclear -Powered Ships Donald W. Pritchard, Chairman, The Johns Hopkins University Edward D. Goldberg Thomas T. Sugihara Scripps Institution of Oceanography Clark University Milner B.Schaefer Lionel A. Walford Inter-American Tropical TT 0 _,. , , ,„.,,,., 0 Tuna Commission U- S' Fish and Wildlife Service James M. Smith, Jr. Warren S. Wooster General Electric Company Scripps Institution of Oceanography CONSULTANTS Arnold B. Joseph Ralph K. Longaker U. S. Atomic Energy Commission Maritime Administration DeCourcey Martin, Jr. Scripps Institution of Oceanography iii

FOREWORD In June 1958, the Atomic Energy Commission requested the Com- mittee on Oceanography of the National Academy of Sciences ' National Research Council to consider the problem of disposal of radioactive wastes from nuclear-powered ships. The Committee on Oceanography asked the Academy's Committee on the Biological Effects of Atomic Radiation on Oceanography and Fisheries to undertake this study. As chairman of the latter Committee, I appointed a special working group under the leadership of Donald Pritchard. Following the first meeting of the working group in September 1958, drafts of sections of this report were written by individual mem- bers. In December, at the second meeting, the drafts were reviewed. Professor Pritchard then consolidated these contributions into a single document. The report was discussed in detail and approved for publi- cation by the Committee on the Biological Effects of Atomic Radiation on Oceanography and Fisheries in March 1959. The report gives a series of detailed and specific recommenda- tions concerning the amounts of different types of radioactive wastes that can be released safely into the sea by nuclear-powered ships. Separate rules are given for each zone of the marine environment. These rules are most restrictive for the innermost zone of harbors, estuaries and coastal waters, and least restrictive for the open sea out- side of fishing areas, more than twelve miles from shore, and where the bottom depth is greater than 200 fathoms. The working group has attempted to make its recommendations as precise as possible within the limits of our present knowledge of the physics, chemistry, and biology of the oceans. Where uncertainties exist because of inadequate knowledge, a conservative position has been chosen - that is, the calculations underlying the recommendations may err on the side of safety. Each assumption and each step in the calcula- tions is fully described, however, so that the reader may make an inde- pendent evaluation of the degree of conservatism of the recommended rules. It is sometimes said that biologists and oceanographers, when considering the introduction of artificial radioactive materials into the sea, tend to pile safety factors upon safety factors to arrive at a quite unrealistic result. I am convinced that any careful reader will conclude this is not true of the present report. One of the most important conclusions of the report concerns the necessity for monitoring and maintaining records of the amount and lo- cation of radioactive waste disposal by nuclear ships. This will involve not only action by each maritime country, but also international agree- ment and collaboration. Roger Revelle

TABLE OF CONTENTS Group Membership iii Foreword by Roger R. Revelle v Summary and Recommendations ix Purpose 1 Scope 1 Brief Description of a Nuclear Ship Reactor and Its Operation 2 Design and Operation 2 Definition of the Term "Wastes" 3 Potential Sources of Radioactive Wastes 4 Amount and Composition of Wastes 4 Predicted Number of Nuclear-Powered Ships 7 General Approach to the Problem 7 Biological Significance of Various Parts of the Marine Environment 11 General Considerations on Criteria of Acceptability 12 Processes Determining the Concentration of Nuclides in the Marine Environment and in Sea Food 13 Physical Effects 13 Geochemical Effects 14 Biological Effects 15 Maximum Permissible Concentrations in Sea Food 15 Special Considerations Related to Harbors, Estuaries and Other Inshore Waters, and to the Continental Shelf 17 Considerations Relative to the Open Sea 18 Subdivisions of the Marine Environment 18 Computation of ppc Values for Sea Food 19 Restrictions on the Application of ppc Values in Sea Food and in the Marine Environment 20 Partial Permissible Concentrations in the Environment 21 Wastes from Nuclear'Powered Ships 23 Basis for Evaluating Safe Discharge Rates 27 Evaluation of Harbors, Estuaries and Other Inshore Environments (Zone 1) 29 The Diffusion Model Employed in This Analysis 31 Evaluation of the Coastal Area (Zone 2) 39 Evaluation of the Outer Continental Shelf (Zones 3a and 3b) 40 Evaluation of the Open Sea (Zones 4a and 4b) 44 Conservative and Non-Conservative Estimates Used in this Report 45 Monitoring and Record Keeping 48 References ....... . . , 51 vii

SUMMARY AND RECOMMENDATIONS This report is an evaluation of: (1) The nature and amount of radioactive waste materials which would conceivably be introduced into the sea through normal operations of nuclear-powered ships. No conclusions are reached concerning the safety of operating nuclear'powered ships in tideless, fresh water bodies. (2) The routes by which such introduced activity would return to man from the sea. (3) The portion of the maximum permissible dose to man, allotted to the peaceful uses of nuclear energy, which should be permitted to orig- inate from waste disposal operations from nuclear-powered ships. (4) The concentration by marine organisms of the various significant isotopes in the wastes. (5) The processes of dispersion of the wastes within the various sub- divisions of the marine environment. (6) The permissible rate of introduction of the subject waste materials into the various subdivisions of the marine environment. This report deals specifically with the wastes which would origi- nate from a water cooled reactor. Other types of reactors will undoubt- edly be used in future nuclear-powered ships; the character and amount of wastes which might be introduced to the marine environment from such future designs cannot now be stated accurately. It is believed, how- ever, that the general conclusions of this working panel can be utilized in formulating design criteria and operating doctrine, with respect to waste disposal into the marine environment, for such future types of marine reactors. In the present report it is assumed that the bulk of the fission prod- ucts remain contained in the spent fuel elements and are removed from the ship with these elements at time of refueling. The two principal types of radioactive waste which could enter the marine environment through the normal operation of nuclear-powered ships are: (a) a low level liquid effluent originating, for the most part, in the primary coolant system; and (b) spent ion exchange resins, used in the by-pass clean-up system for the primary coolant. Other possible sources include

contaminated expendable tools, glassware, etc., which would be packaged before discharge. The liquid effluent will contain low concentrations of radioactive corrosion products together with very much lower concentra- tions of fission products. The ion exchange resins will contain consid- erably higher activities of these same materials. The following subdivisions of the marine environment are con- sidered: (1) harbors, estuaries, and coastal waters out to two miles from the shoreline; (2) the coastal area between 2 miles and 12 miles from the coastline; (3) the outer continental shelf, extending from 12 miles offshore outward to the 200 fathom depth contour; (4) the open sea, here considered to comprise those ocean areas more than 12 miles from shore having depths greater than 200 fathoms. For the last two categories, a further distinction is made between fishing areas and areas which do not contribute materially or directly to the commercial harvest of sea food. On the basis of reports dealing with the U.S.S. NAUTILUS and the proposed N.S. SAVANNAH, a list is made of isotopes with half lives longer than 6 hours which are likely to occur in significant quantities in the primary coolant and the ion exchange resins of marine pressur- ized water reactors. For each of these isotopes the partial permissible concentrations (ppc's) in seafood and in the marine environment are de- termined for each of the above listed subdivisions of the environment. Assuming that the relative proportions of the various significant isotopes in the wastes do not vary greatly, a weighted mean ppc value for the va- rious subdivisions of the marine environment, for each type of waste, is determined. The relative compositions of the wastes predicted for the SAVANNAH and observed for the NAUTILUS differ somewhat, and hence a different weighted mean ppc value is determined for the primary cool- ant and for the ion exchange resins, for each of these two types of ship. The predicted nature and quantity of the potential wastes from the SAVANNAH, and the observed nature and quantity of the wastes from the NAUTILUS, are utilized in arriving at the conclusions and recommenda- tions presented here. A similar evaluation can be made for any potential waste of known relative composition, by use of the appropriate weighted

mean partial permissible concentration (ppc) values for that waste. If MA represents the activity in the waste resulting from a given jsotope, i, and (ppc); represents the partial permissible concentration for the sub- ject environment for that isotope, then the weighted mean ppc value for the environment, for that waste, is given by ZM. We" • ' The weighted mean ppc value is utilized with the gross activity result- ing from the isotope mix. It has the advantage of providing a convenient means of including the additive effect of the various isotopes contained in the wastes. The maximum number of discharges, N, which may be made into a representative segment of each of the subdivisions of the marine en- vironment during any one month period is determined as a function of (a) the total activity in a single such discharge and (b) the environmental ppc value. These determinations are based on an evaluation of the rates of dispersion and exchange in the marine environment. The limitations to our present knowledge of these phenomena require us to use conserv- ative interpretations of the results. If the permissible number of dis- charges, for a given activity, into a representative segment of the marine environment is computed to be less than one per month, that environment is considered to be unsuitable as a receiver of that particular waste. Our conclusions and resulting recommendations for each of the environmental subdivisions are as follows: Harbors, estuaries, and coastal waters out to two miles from the shoreline (Zone 1): The considerable variation in the physical processes of dispersion within, and exchange between, segments of this marine environment, as well as local variations in the biological and geochemical processes of importance to our problem, makes it impossible to present a completely general conclusion regarding waste disposal into harbors, estuaries and other inshore areas. Since these are areas of high human activity, it is evident that solid wastes should not be introduced into such waters. Be- cause of the poor dispersion characterizing tideless harbors which are separated from the sea by locks, it is questionable whether any radioactive wastes should be introduced into such waterways from nuclear-powered ships.

An evaluation is made of a "typical" harbor of poor flushing char- acteristics. The results are summarized in the following table, which gives the maximum permissible total activity for a single discharge, as a function of selected values of the ppc value for the environment and the maximum permissible number of discharges per month. ppc value Permissible Activity in a Single Discharge for the For 1 discharge For 30 discharges environment per month per month (ne/ml) (curies) (curies) 10'' 2.5 xlO'2 2.5 x 10'3 IO'8 2.5 x 10'1 2.5 x I0'2 lO'7 2.5 2.5 x lO'1 The weighted mean ppc value for the inshore environment com- puted for the primary coolant of the SAVANNAH is 2 x 1 O'8 nc/ml, and the predicted gross activity which would be contained in the warm-up expansion volume from this primary coolant is 6.8 x 10'1 curies. Hence this "typical" harbor would be unsuitable as a receiver of warm-up ex- pansion volume wastes from nuclear-powered ships having the activity characteristics predicted for the SAVANNAH. The weighted mean ppc value for this marine environment com- puted for the primary coolant of the NAUTILUS is 4 x 10'8 uc/ml, and the observed average activity due to the significant isotopes contained in the normal warm-up expansion volume of 500 gal is 1.4 x 10'2 curies. Hence apparently this "typical" harbor could receive a maximum of over 10 discharges per day of warm-up expansion volume wastes from nuclear - powered ships having the activity characteristics observed for the NAUTILUS. While relatively poor flushing characteristics were chosen for the harbor used in these sample computations, they do not represent the most restrictive conditions which might be encountered in marine harbors. Also, because of lack of adequate data, it was not possible to include the potential effect on bottom-living animals and plants, of concentration by the bottom sediments. For these reasons the recommendations which follow are somewhat more conservative than might otherwise be drawn from the above numerical results. Since the total activities on the spent ion exchange resins, as pre- dicted for the SAVANNAH and observed on the NAUTILUS, are 100 to xii

400 curies, and 12.5 curies, respectively, it is evident that wastes from ion exchange beds cannot be discharged into harbors and other inshore waters. Our recommendations pertaining to harbors, estuaries, and other inshore environments (Zone 1) are as follows: Recommendation 1: No solid radioactive wastes or spent ion exchange resins should be discharged into harbors or estuaries, or into coastal waters within 2 miles of the shoreline, from nuclear-powered ships. Recommendation 2: Nuclear-powered surface ships should be equipped with tanks capable of containing any liquid wastes which accumulate dur- ing the time such ships are in harbors, estuaries and other inshore waters, and such wastes should not be discharged until the ship has reached the open waters of the continental shelf. (Restrictions on dis- charges in this latter environment are treated later in this summary.) Other means of restricting the introduction of such wastes into the in- shore environment would also be allowable. Recommendation 3: For certain special types of nuclear -powered ships, other than surface ships, for which Recommendation 2 would result in significant operational disadvantages, the requirements of that recom- mendation may be relaxed providing that: (a) Detailed evaluation of each specific major port of call and harbor base for such vessels be carried out using the general approach outlined in this report, such evaluation serving to establish the permis- sible activity and frequency of discharge. Actual discharges should be maintained well below the maximum permissible number and activity until the results of detailed environmental monitoring are available, and in any case should be maintained as much below the maximum permis- sible as is technically feasible. (b) A detailed monitoring program be maintained, on a continuing basis, in the vicinity of each nuclear ship base and major port of call. (See also Recommendation 11.) The coastal area, between 2 miles and 12 miles from the shoreline (Zone 2): A 10 mile wide segment of this subdivision, extending from the in- shore edge to the offshore boundary and considered as a ship traffic route, was employed in the sample computations for the inner continental xiii

shelf. Because of the possibility of accidental recovery, no solid wastes should be introduced into this environment. The results of the evaluation for the liquid effluent are summarized in the following table, which gives the maximum permissible total activity for a single discharge as a func- tion of selected values of the ppc value for the environment and the max- imum permissible number of discharges (N) per month. ppc value Permissible Activity in a Single Discharge for the For 1 discharge For 30 discharges environment per month per month ) (curies) (curies) 10'9 5.2 x 10° 5.3 x 10'2 10'8 5.2 5.3 xlO'1 10'7 52 5.3 The weighted mean ppc value for the coastal area, for the primary coolant of the SAVANNAH, is 2 x 10'8 nc/ml and the predicted gross ac- tivity which would be contained in the warm-up expansion volume of some 2200 gallons is 6.8 x 10'1 curies. Thus, considering that it would be un- likely that more than 30 nuclear-powered ships per month would pass, out- bound, through any such 10-mile wide stretch of the coastal area, this environment appears suitable to receive the low level liquid wastes which would be stored in tanks as a result of restrictions placed on the release of such wastes in harbors. This zone does not appear suitable, however, to receive the 10 to 400 curie amounts of activity which might be released with the spent ion exchange resins. Our recommendations pertaining to the coastal area, between 2 and 12 miles offshore (Zone 2), follow: Recommendation 4: Spent ion exchange resins should not be discharged from nuclear-powered ships into the waters of the coastal area, between 2 and 12 miles offshore. Except under very exceptional circumstances there should be no discharge of packaged solid wastes from nuclear- powered ships into these waters, and any such exceptional discharge should conform to recommendations contained in the National Academy of Science's report "Radioactive Waste Disposal in the Atlantic and Gulf Coast" (NAS-NRC Pub. 655, 1959). XIV

Recommendation 5: Low level liquid effluent may be discharged into the waters of the coastal area, between 2 and 12 miles from shore, pro- viding that the total activity contained in any single discharge does not exceed 5 x 10'1 curies resulting from isotopes with half-lives of more than 6 hours. The outer continental shelf, from 12 miles offshore to the 200 fathom depth contour (Zones 3a and 3b): The continental shelf off the east coast of the United States was employed in the sample computation for the outer continental shelf. The results of the evaluation for a liquid effluent or for the discharge of ion exchange resins are summarized in the following table, which gives the maximum permissible total activity for a single discharge as a function of selected values of the ppc value for the environment and the maximum permissible number of such discharges per month. ppc value Permissible Activity in a Single Discharge for the For 1 discharge For 30 discharges environment per month per month (lJ,c/ml) (curies) (curies) IO'9 23 2.4 10'8 2.3x102 24 lO'7 2.3 x 10 3 2.4 x 102 This region has a much greater capacity for receiving waste ma- terials than the coastal area, and the release of low level liquid wastes from nuclear -powered ships into waters of the outer continental shelf apparently presents no serious problem. For fishing areas of the outer continental shelf (Zone 3a), the weighted mean ppc value for the spent ion exchange resins of the SA- VANNAH is 2 x 10'8 nc/ml. Since as many as 30 discharges per month onto the continental shelf of the eastern United States could conceivably result from the activity of 300 nuclear-powered ships, the maximum permissible activity per discharge would be about 50 curies. Since the predicted activity on the spent ion exchange resins of the SAVANNAH will be 100 to 400 curies, it is evident that no release of such resins into fishing areas of the outer continental shelf should be allowed. xv

For this zone, the weighted mean ppc value for the wastes from the spent ion exchange resins of the NAUTILUS is computed to be 6 x 10'^ [iC/ml. The above table then indicates that the gross activity per dis- charge for such wastes should not exceed about 14 curies, at the rate of 30 discharges per month spread over the entire continental shelf of the eastern United States. This 14 curies is approximately equal to the ob- served gross activity on the spent ion exchange resins of the NAUTILUS. For non-fishing areas of the outer continental shelf (Zone 3b), the ppc value for the wastes from the spent ion exchange resins on the NAUTILUS is 3 x 1(T8 nc/ml. Thus the gross activity per discharge for such wastes introduced into this environment should not exceed about 70 curies per discharge, for a maximum of 30 such discharges per month randomly distributed over the outer continental shelf off the east coast of the United States. This is approximately equivalent to one discharge per month in any 100 mile wide slice of this shelf. The continental shelf region selected for the sample calculation may not be the most restrictive segment of the continental shelf of the world ocean, from the standpoint of radioactive waste disposal. There- fore the recommendations which follow are somewhat more conservative than would be drawn from a strict application of the numerical results. Recommendations for the outer continental shelf, from 12 miles offshore to the 200 fathom depth contour (Zones 3a and 3b), follow. Recommendation 6: No discharge of spent ion exchange resins from nuclear-powered ships should be made into known fishing areas of the outer continental shelf, from 12 miles offshore to the 200 fathom con- tour line. Except under very exceptional circumstances there should be no discharge of packaged solid wastes from nuclear-powered ships into these waters, and any such exceptional discharge should conform to recommendations contained in the National Academy of Sciences' re- port "Radioactive Waste Disposal in the Atlantic and Gulf Coast" (NAS- NRC Pub. 655, 1959). Recommendation 7: If denser than sea water, spent ion exchange resins from nuclear-powered ships may be discharged into non-fishing areas of the outer continental shelf, from 12 miles offshore to the 200 fathom contour, provided that the activity in any single discharge shall not ex- ceed 50 curies, and also provided that such discharges be restricted to ships which could not, without appreciable loss in efficiency, limit such discharges to waters of the open sea having depths exceeding 200 fathoms. Thus ships inbound from an ocean passage should schedule discharges, xvi

which might actually become due during transit of the continental shelf, while still in waters exceeding 200 fathoms in depth. Ships outbound for an ocean passage should delay discharges, where practical, until after having passed into waters of over 200 fathoms in depth. Discharge may be made only when the ship is under way and more than 3 miles from a neighboring vessel. Recommendation 8: No restriction need be placed on the discharge of low level liquid effluent from nuclear-powered ships into waters of the outer continental shelf, provided that the composition and amount of ac- tivity in such wastes are of the same general character as that predicted for the primary coolant of the SAVANNAH or observed for the primary coolant of the NAUTILUS. The open sea, more than 12 miles from any shore, and having depths greater than 200 fathoms (Zones 4a and 4b): This segment of the marine environment has a greater capacity for receiving radioactive wastes than any of the other subdivisions con- sidered in this report. The area of the open sea which is employed in this sample computation consists of the North Atlantic trade route from New York to London. The results of the evaluation for this environment are summarized in the following table, which gives the maximum per- missible activity for a single discharge as a function of selected values of the ppc for the environment and the maximum permissible number of such discharges per month. ppc value Permissible Activity in a Single Discharge for the For 30 discharges For 300 discharges environment per month per month (ne/ml) (curies) (curies) I0'9 9.5x10 2x10 lO'8 9.5 xlO2 2xl02 10'7 9.5 x 103 2 x 103 For fishing areas of the open sea (Zone 4a), the weighted mean ppc value for the spent ion exchange resins of the NAUTILUS is 1 x 10'8 nc/ml, and for non-fishing areas (Zone 4b), 7 x 10'8 uc/ml. The corresponding values for the SAVANNAH are slightly higher. If 300 nuclear-powered ships should each discharge spent ion exchange resins 6 times a year, there would be on the average 150 such discharges per month. If all these xvii

ships operated along the trade route from New York to London, which has a length of about 6000 km and a width of about 100 km, interpolation from the above table indicates that the gross activity for a single dis- charge should not exceed 310 curies for fishing areas of the open sea, and should not exceed 2200 curies for non-fishing areas of the open sea. As a result of the recommendations made for the continental shelf, there will likely be some bias in the distribution of such releases in the open sea which would result in a somewhat greater concentration of discharges near the continental slopes. The recommendations for the open sea (Zones 4a and 4b) which are given below reflect this possibility. Recommendation 9: Spent ion exchange resins from nuclear-powered ships may be discharged into the waters of the open sea at distances of more than 12 miles from shore and in depths greater than 200 fathoms provided that the gross activity of a single such discharge does not ex- ceed 500 curies, that the frequency of such discharges from a single ship does not exceed one per month, and finally, that no such releases be made into the major designated oceanic fishing areas. Discharge may be made only when the ship is underway and is more than three miles from any neighboring vessel. In view of the distinctions made in these recommendations be- tween fishing areas and non-fishing areas, a further recommendation is required. Recommendation 10: The Bureau of Commercial Fisheries of the Fish and Wildlife Service should prepare a chart of the world oceans, showing those areas of the continental shelf and open sea which should be con- sidered as commercial fishing areas. This chart should be issued by the Coast and Geodetic Survey and by the Hydrographic Office, and should be utilized by officers of nuclear-powered ships in carrying out the recommendations pertaining to the outer continental shelf and to the open sea given above. Finally, this working panel makes the following recommendation regarding monitoring and registry: Recommendation 11: Immediate steps should be taken to initiate the proposals contained in the section of this report entitled "Monitoring and Record Keeping". XVlll