audience. Do the current radiation standards need revision and, if so, in what direction?

eisenbud. Standards, of course, are always in need of revision, par­ticularly when the spectrum of standards is as complex as those we are dis­cussing here. Leo Marinelli of Argonne has just published a paper which gives good evidence, on the basis of recent studies of the relative toxicity of radium and 90Sr, that the present 90Sr figure in bone could possibly be increased by a factor of three or four. In the normal course of events, if this were done (and I’m not saying that it will), it could easily take the ncrp three to five years to arrive at a consensus. There may be other situa­tions in which changes should be in the other direction. Thus, I would say, yes, there are needs for changes, but I don’t see the need for any revolu­tionary changes. Rather, I see the need for evolutionary changes of the type we’ve always had.

stannard. I have stated that I do not feel that the risks involved in the present basic standards are unacceptable to me as a biologist. On the other hand, I think many of the details—particularly those involved in setting levels for exposure in air or mpc’s in air or water, and those related to the peculiarities of behavior of a given radioisotope or of a given com­pound of that isotope — are going to need revision in the foreseeable fu­ture. Also, any risk must have its compensating benefit. To some these do not compensate for risk. But I speak of the ability of our species to tolerate the risk as a problem in biology. Many radiobiologists feel that they may be coming to the point of diminishing returns in the current expensive long-term experiments; they may not have the patience or money, particu­larly under present conditions of reduced budgets, to see through even some of the long-term animal experiments that are under way let alone mount new ones. I believe there is enough need for the additional infor­mation that anyone concerned with standards should support and advo­cate the continuation of needed experimental work.

tamplin. My only comment, in respect to standards, is that they should reflect the biological processes that intervene between the intro­duction of radioactivity into the environment and its subsequent deposi­tion in and effect, if any, upon the tissues of man. In the code of regula­tions, the standards should be so spelled out that they represent meaning­ful numbers in terms of the concentration of radioactivity in the diet that man will consume.

auerbach. Speaking from an ecological context, I do not believe that the basic standards we have now are justifiably in need of revision of the basis of ecological data. We perhaps have much research and informa­tion gathering to do before we are able to state that a particular standard for a particular isotope is still too low. The standards we have today are still a good basis for nuclear operations. However, we should continue re­search to test their long-term validity.

lieberman. Certainly the experience to date does indicate that the public’s health and safety have been protected in the peaceful uses of nu­clear energy. However, I do think that continual review of the effective­ness of control and the safety of current levels of protection in view of ex­panding operations is essential; changes must be made as required and as permitted by continuing experience.

commoner. Every standard which is in operation today is directly related to one’s moral attitude toward the value of human life and to the value of the operation. In other words, in my view, there is no objective, scientific way to establish a standard. Therefore, if people of the United States want, by reason of their moral views, to propose more stringent standards, then, the standards ought to be more stringent. I do want to re­mark, though, on that part of the standard related to the evaluation of the biological risk because that’s what morality considers. It is perfectly clear that all of the standards are now at fault for failing to take into account multiple effects. They deal with the effects isotope by isotope; they do not take into account the influence of other toxic substances or different tem­perature changes on radiation effects. Hence, I must disagree with Dr. Auerbach. In my view, the present standards are ecologically unaccepta­ble because they do not take into account the complexity of the ecosystem which, as Dr. Tamplin pointed out, is the vehicle through which the insult is delivered to the human body. So, I recommend an ecologically based revision of all standards relative to risk.

hosmer. Standards, of course, are not static things. They must be dynamic, and change with new data, with new circumstances, and, possi­bly, with changing political attitudes or even mutating psychological con­siderations. Sometimes, people need a Linus blanket, and just possibly some changes in radiation standards might furnish it. But, in any event, values continually change, not overnight, but over the months and over the years; some things become more valuable tomorrow than they are to­day. Some risks become more acceptable or less acceptable. And, if we approach regulation from a philosophy of balancing risk against benefits, then, as the scale changes, we have to revise our standards.

green. I don’t know whether or not the radiation protection stand­ards require any changes, but I am fairly certain that the procedures for setting the standards and reviewing the standards do need changes. I think the problem of setting and reviewing radiation protection standards is far too important to entrust to the experts.

abrahamson. I should like to direct a question to Dr. Eisenbud. It has been suggested that fossil fuel plants discharge relatively more biologi­cally significant radioisotopes than do at least some nuclear plants. Would Dr. Eisenbud care to comment one way or the other?

eisenbud. This refers to a paper which Petrow and I published in Sci­ence in 1964 which shows that, in round numbers, the fossil fuels in coal contained on the order of 1 to 3 parts per million of uranium and thorium along with the various degradation isotopes and that, when the coal is burned, the fly ash contains radioactivity. In the case of oil, there is less uranium and thorium, but the petroleum underground has the character­istic, well known to chemists, of absorbing the noble gases from the ground. The noble gases have a high solubility in fats and oils so that the radon tends to migrate into the oil underground and decays to 210Pb, which has a 22-year half-life. Then 210Pb appears in the effluent of oil­burning plants. Also, natural gas contains some residues of radon and 2l0Pb. Allowing for the fact that both 226Ra and 228Ra, emitted by fossil fuel plants, are among the most toxic of the radionuclides in terms of the ratio of the mpc, the two isotopes 226Ra and 228Ra are far more toxic than 181I or 85Kr, which are emitted by nuclear reactors (at least by pressurized water reactors, the only kind for which data were available in those days). Thus, a few laboratory analyses demonstrated the fossil fuel plants, curi­ously enough, put out more radioactivity than the reactors. Our work has been repeated by others and confirmed.

audience. I don’t think this panel quite balances, and I’d like to ask two questions. Is it true that Lauriston Taylor said that the standards were established mainly to achieve practical capability within the going facts related to the cost of safety? Second, is it true that the standards are only a paper crutch that the industry uses to justify their practical working level? I recall that when 80Sr in milk from animals from North Dakota ap­proached the standards, a committee met and doubled the standards.

abrahamson. The question, in essence, seems to be, Were the stand­ards not determined on the basis of what the industry needed rather than in the interest of public safety?

ramey. Dr. Taylor testified in the Joint Committee Hearings on Ra­diation Standards that were held in 1959, 1960, and 1962, where he out­lined the philosophy of the National Committee on Radiation Protection. As I recall, he made the point that in establishing standards, there were judgment factors involved. There was a fair amount of discussion of the costs to the industry and to the various users involved in setting standards.

brungs. The standards for temperature levels are derived in a much different manner. In our agency, in the Department of the Interior, the Water Quality Act of 1965 set up a program for states to develop stand­ards which would be approved, disapproved, or worked out with the De­partment of the Interior. Basically, states need federal approval of their standards. The Act was written so that standards are not to be fixed in time or in place; any data coming up that would warrant a change in standards in either direction would be well considered. In fact, some stand­ards that we approved as recently as two years ago are undergoing change at the present time to be compatible with more recent knowledge. abrahamson. More stringent or less stringent? brungs. More realistic.

audience. When the experts enter a public sector, I feel that I am also an expert. The democratic process of this country places decision-making powers in as large a group as possible. I was reminded of that again to­night when Congressman Hosmer said, “values continually change. . . if we approach regulation from a philosophy of balancing risks against benefits, then, as the scale changes, we are going to have to revise our standards.” In the case of atomic energy and genetic damage, then those values bear on human life. I don’t think our values have changed there. I want to know how Congressman Hosmer feels about that. Further, if there are deficits, who do those deficits fall upon?

hosmer. I think that Dr. Stannard was right when he said that these standards were set over half a century not only by experts, but by govern­ment leaders of the world; because the public cannot actually vote on ra­diation standards, it takes its part in the decision through its leaders. Ac­tually, in standards-setting groups, there are opportunities for the public to put its ideas across in hearings. And there are opportunities for experts who disagree with the standards to go to the frc which sets them, instead of to the newspapers, so that their ideas can be evaluated by their peers in scientific expertise.

I spoke of benefits in terms of risks, and what society does by way of imposing risk. Society must balance risk against potential benefits to the people; the ultimate decision should be that which is the greatest good for the greatest number.

ramey. A further part to that question was, How can the public par­ticipate in standard making? The aec’s standards for the siting of reactors, for effluents, and so on are adopted through the established federal meth­od of publishing them as proposed regulations in the Federal Register.

Thereafter, 45 or more days are allowed for comment. The public may also participate through Congress and the established committees of Con­gress in the atomic field. The most signicant of these is the Joint Commit­tee on Atomic Energy. The public is invited to come before that commit­tee and to comment on the standards and the activities of the aec. As a matter of fact, you may be aware that, at the end of this month and into November, the Joint Committee is going to have extensive hearings on en­vironmental matters, including standards. (For an expanded discussion of this subject, see remarks by James T. Ramey made at Madison, Wiscon­sin, on April 4,1970.)

commoner. Congressman Hosmer, are you ready to accept that the new Minnesota standards are valid in Minnesota since they reflect clearly the opinion of the people of Minnesota?

hosmer. I have been in Minnesota almost 24 hours. People have told me that these standards are a political football here, and I know they are in Washington among the Minnesota delegation. So, I’m not willing to accept them for that reason, and, secondly, because the Atomic Energy Act of 1954, as amended, clearly preempted the regulation of effluents from nuclear power plants, just as the legislation on commercial aircraft preempted the regulation of airlines and commercial airline pilots. These preemptions were taken on the same good basis — that these are national problems and therefore in the federal domain.

abrahamson. I have a written question directed to Dr. Zabel: It has been stated that additional complexity can result in a net negative gain in nuclear plant safety. The weighting of this is not a trivial matter. How is the weighting accomplished? Or, what methods of evaluation are at your disposal?

zabel. I should say first that I’m expressing my own opinions; they may or may not represent the aec’s or anyone else’s opinion. As far as evaluation by the Advisory Committee on Reactors’ Safeguard is con­cerned, 15 people have to search their souls. Some questions can be analyzed numerically, but some cannot. I’ve seen committee members really sweat a decision. These things cannot be put up for a vote by 200 million people. I don’t know if the size of group we happen to have in the acrs is adequate. The members are a cross-section of people, some of them not even in the nuclear business, and I believe they try hard to rep­resent the public. No matter who serves, no matter how large or small a group, if the members are making a decision in thrashing with these prob­lems, they become the experts, like it or not.

audience. I would like to ask Dr. Eisenbud about his and H. G. Petrow’s paper, “Radioactivity in the Atmospheric Effluents of Power

Plants That Use Fossil Fuels” (Science, 1964, 144, 288-289). Is it a fact that a fossil fuel plant would discharge more biologically significant radio­isotopes into the atmosphere than a nuclear plant of comparable size? What plant were those conclusions based on? Would you agree with them today?

eisenbud. The only nuclear plants in operation for which data were available to me then were Dusquene, Yankee, and Indian Point. Dresden was operating, but I hadn’t seen any data from it at that time. I don’t think there is anything in that report about which I would equivocate.

audience. The purpose of the question was, frankly, to determine whether you still believe the conclusions of the paper. Have they been borne out? If so, then many of our worries are fruitless.

eisenbud. The statement is correct. I am embarrassed that many people, in discussing that paper, have attempted to construe it as saying the radioactivity from these fossil fuel plants was a health hazard. We never said that. All we said was that the amount of effluent from a fossil fuel plant is not significant from a public health point of view, and that which comes from a pwr is even less significant.

audience. But nobody participating here would dispute those facts? commoner. Dr. Eisenbud, if modem fly ash precipitators were applied to the coal plant question, would the situation change?

eisenbud. My recollection is that we had a 97 per cent efficient pre­cipitator in that calculation.

audience. Dr. Eisenbud, you stated that your study compared pres­surized water reactors with fossil fuel plants. If boiling water reactors turn out approximately a 100,000 times greater gaseous discharge than do pressurized water reactors, the dose equivalent basis is about 10,000 times greater. It would seem that discharges from boiling water reactors are not comparable with those from fossil fuel plants.

eisenbud. I would prefer to refer that question to the members of the Bureau of Radiological Health. I haven’t done anything on this since 1962, but I think the Bureau of Radiological Health has some recent data. In particular, the amount of sulphur dioxide emission is relevant.

lieberman. I can only refer to the actual measured results that the Bureau of Radiological Health got from the Dresden plant (pp. 65-66). abrahamson. So you cannot make the comparison? lieberman. The calculation could be made. But in terms of the comparison, none of the emissions are at environmental levels of signifi­cance to public health.

abrahamson. Do you have the numbers at your disposal? lieberman. No, I don’t have any comparative numbers here.

Ill

eisenbud. I do recall, though, that the amount of air required to dilute the emissions from a fossil fuel plant (a coal burner), diluted to the mpc for the chemical constituents, is 30 times greater than the amount of air necessary to dilute the effluent from the boiling water reactor to the MPC.

abrahamson. Dr. Stannard, in the discussion on the levels of maxi­mum permissible dose of radiation, it was implied that there are many ways in which we receive radiation and other pollution from the air and water and that there are potential health hazards in various aspects of these things. When the mpd’s are set up, has it been taken into account that our health is also being adversely affected by other pollution and by radiation from natural causes?

stannard. The answer is no, in terms of the basic radiation standards vis-a-vis other potential pollutants. However, safety factors are introduced regularly which have that effect. These safety factors enter because the basic standard is always set somewhere below the acceptable risk and much below the level of known overt damage. Also, in the operations of icrp, ncrp, and, for that matter, the frc there is always the admonition to hold to the lowest practicable levels.

The point is a good one, however. For a total evaluation of the im­pact of all factors in our environment on the future of mankind or on our own individual welfare, we should try to do what the question implies. Someone mentioned earlier that radiation standard review was too com­plex for the experts. If a review of radiation alone is too complex, where are we going to get the people and data to evaluate the total environment without a very large effort? Dr. Commoner feels that this is the crux of our situation. It is indeed much more the crux than radiation standards per se.

Regarding the last part of the question, on damage from natural back­ground radiation, let me remind you that the standards are above back­ground but do not ignore it. Proof of damage from background radiation is, of course, not available.

commoner. The whole question of synergistic effects of various environmental stressors is very important. I agree with Dr. Stannard that more work has to be done. It is a huge undertaking, but such factors need to be better identified.

audience. Mr. Bray, can you comment on the radioactive releases from a boiling water reactor being 105 times the releases from a pres­surized water reactor?

bray. No, we haven’t done any relative studies either on other re­actor systems (our company manufactures only bwr’s) except that we’ve done considerable studies relative to the regulations.

abrahamson. These numbers last appeared in one place in the United Nations conference held during this last year in a paper by Morton Goldman on airborne wastes from nuclear power plants. He is with the N. U.S. Corporation, Washington, D. C.

audience. There have been numerous comments on the need for more ecologically oriented research. Does the aec, in fact, have a staff of ecologists?

ramey. The aec, in this current fiscal year (July 1, 1969-June 30, 1970), is spending around $89,000,000 for biological and medical re­search, of which a fairly large portion has environmental significance. I am sure that Dr. Auerbach would like to spend more money in this area. The aec does its work not directly through government employees, but through contracts at government-owned installations that are operated by universities or other organizations. The research is carried on by such organizations as the Oak Ridge National Laboratory and the Argonne National Laboratory as well as under a great number of smaller contracts with universities. Around $9 or $10 million a year goes for work that would be classified as ecological research and development related to land and fresh water. An additional $9 million is expended each year on ocean and atmosphere work having ecological significance.

abrahamson. What proportion is this of the total aec non-weapon budget?

ramey. The biological and medical budget is about 10 per cent of the total non-weapon budget (and the amounts appropriated for such research have been going up each year). We have been fortunate in getting, through the support of Congress, the Joint Committee on Atomic Energy, and the appropriations committees, what is called reasonable growth. Again, not so much as we would like and especially not so much as our laboratories would like.

auerbach. I am an employee of the Union Carbide Corporation, and, as such, a contract employee supported by the aec through the Oak Ridge National Laboratory. As Mr. Ramey says, the budget for terrestrial and fresh water ecological research has been between $9 and $10 million a year. To place that figure in context, I should say that the aec’s budget for ecological research covers a vast array of different kinds of studies, all concerned broadly with the understanding of natural systems, aec has put more money into basic ecological research than any other federal agency —far more over the past ten years than the National Science Foundation. Most of the original work in the study of ecosystems has been supported by aec.

In the country today, there really are two kinds of ecology being

bandied about, and both are quite legitimate. But, we should keep them in proper perspective. There is the traditional ecology, which is the study of organisms, populations, and so forth in response to their environment; it is the science of interactions. There is also a new ecology, which is con­cerned, in part, with human values in relation to the environment. It is not appropriate yet to mix these two — at least I, as a scientist, am not capable of mixing these two. I can talk only in terms of ecology as a science which, in this instance, is concerned with the effects of ionizing radiations. When one talks about the effects on human values, it is quite another matter.

commoner. Let me disagree with Dr. Auerbach in the following way. There are, indeed, two kinds of ecology abroad right now, and he described one of them very accurately: the study of the interaction be­tween an organism and its environment. The second kind of ecology he referred to does not exist, in my opinion; I know of no ecology which, as a science, takes into account, in an objective, scientific way, human values. However, there is an orthodox ecology, which often limits itself to arti­ficially defined systems —such as a pond. More recently, ecology has begun to include in its scope the properties of systems in which people live, such as the state of Minnesota. This kind of ecology, the kind that deals with the air that we breathe and with what is actually happening in the Mississippi River to the water that we drink, elicits a human response.

ramey. Certainly, some of the ecological studies that are projected, and some which are under way, do deal with whole river and lake systems. For example, the Argonne Laboratory is undertaking a study of the ecology of Lake Michigan and the role of nuclear power plants and fossil power plants in that whole lake system. At Hanford, Washington, for more than 20 years, we have been conducting ecology studies of the Columbia River as a system. Various computer techniques and other means of trying to relate some of the factors involved in those systems have been developed. We have not been able to do everything, by any means, but from a scientific standpoint, we are not just looking at proto­zoa in some pond. I agree that it makes a significant difference whether one is studying a pond or a total drainage basin composed of a whole composite of ecosystems, but the aec is looking at systems and certainly hasn’t ruled out expanding the research to cover drainage basins in other areas. The investment in ecology made by the aec has been singularly impressive, and the number of workers in this field has been limited only by the $18 million allotted for research which covers oceanography as well as freshwater, terrestrial, and atmospheric aspects.

eisenbud. We are getting to the point now in social development where we can no longer think of ecology as the kind of thing that ecol­ogists do. There are many things touching on the interaction of man and his environment which are done by non-ecologists who have an ecological point of view. For example, I would describe in ecological terms all of the toxicological work supported by the aec, all the radiobiological work, all of the extensive studies of inhalation physiology to determine what hap­pens when a person inhales a dust particle. The work we did some years ago at New York University, in which we related the amount of iodine in the environment to what turns up in kids’ thyroids and determined its progress through the food chain mechanisms, was ecology; it was done not by ecologists but by people with an ecological point of view. If you describe ecology in this way, I think that the budget of the aec is very much larger than $9 or $ 10 million a year.

audience. Dr. Lieberman, my understanding is that the drinking wa­ter standards of the U. S. Health Service haven’t allowed for gross activity of 1,000 pCi per liter. My understanding is that the aec standards for emission is at 100 pCi per liter, or ten times more restrictive than water standards. What is the Public Health Service doing to upgrade their stand­ards?

lieberman. The explanation of the difference between the phs drink­ing water standards and 10CFR20 is the condition that must be applied to the sample being analyzed based on the knowledge of the absence of certain radionuclides. The phs limit of 1,000 pCi/І is used when it is known that 90Sr and alpha emitters are absent. In the applications of 10CFR20 (100 pCi/І) for gross beta it is known that 129I, 226Ra, and 228Ra are not present. People in the Bureau of Radiological Health and Bureau of Water Hygiene are presently reviewing the whole question of drinking water standards.

audience. One of the reasons I am here is to see how the participants approach the problems that they work with as men. I wanted to see what the depth of their information was and how they regarded the problems they face. When Mr. Bray, who is the Manager of Systems Engineering for the Atomic Power and Equipment Department of General Electric and who is responsible for the basic design details and the evaluation of all ge boiling water reactors, says he does not know what the ratio is between the gaseous effluents of boiling water reactors and pressurized water re­actors, I would like to ask him why, in his position, he does not know what these ratios are.

bray. It’s not important that I know the differences between the ef­fluent release rates of pwr’s and bwr’s, but rather that I know what the effluents are from the boiling water reactor. As for the releases in pres­surized water reactors, although I worked with them in the naval pro­gram, in the last ten years I have had no need to know exactly what these effluents are. I do know, however, that although the liquid waste discharge from pwr’s is greater than from bwr’s, the gaseous waste is less. That is due to specific differences in the two designs. Therefore, the use of simple ratios in a particular discharge is not too meaningful. My primary respon­sibility as a designer is to check my design against appropriate regulations.

audience. Are the doses from other power plants that might exist taken into account when release limits, licensing, and so forth are deter­mined for a particular plant?

eisenbud. Although I cannot speak for the aec on this, certainly the ncrp believes that the total exposure to the public should be limited to.17 rad/yr. It would be up to the people who are administering the pro­gram, in this case the aec, to decide how this dose should be apportioned. In situations where two or more plants stand on a single site, for all prac­tical purposes these will be treated as a single plant. In other words, the emissions to the stream or to the atmosphere will be controlled as though they were just one plant.

bray. It is my understanding that whenever there is more than one plant on a particular site, the site is treated, with respect to the limits and the limitations both with gaseous waste off-site or liquid waste, on a plant site basis. So, the plants would be treated collectively if there together, and the integrated effect would be taken into consideration when looking at them separately.

audience. What would be the cost for the cooling towers necessary to affect the heat discharges to the water environment from a typical re­actor of, say, 500 megawatts?

brungs. In terms of construction dollars, the towers would run to millions of dollars. I prefer to look at cost to the consumer, via increased utility rates. There the cost varies with the situation, but it is around a 4 per cent increase in rates for complete cooling before discharge versus no cooling whatsoever.

hosmer. The question of dumping heat into water should not be considered in isolation. A cooling tower sends the heat into the air. Water cooling sends the heat into water first, then the air. The heat has to go someplace. Since modem conventional steam plants are 40 per cent effi­cient, 60 per cent of every 100 btu’s does not make electricity, but goes into the environment. Modem atomic plants are about 35 per cent effi­cient, so 65 per cent goes into the environment. Now, in the case of the conventional plants, some of the heat goes up the stack and elsewhere, and about 75 per cent of the wasted btu’s goes into the water unless air cooling is used. In the case of nuclear plants, all unused btu’s go into the water — 65 per cent. Cooling towers don’t automatically solve the prob­lem. The moisture they add to the atmosphere may cause considerable climatic changes, on a local basis. So there are many subproblems to be considered.

abrahamson. Would you care to elaborate on the climatic effects?

hosmer. In many cases, in the wintertime, water particulates lead to an increasing incidence of fog or sleet. The results depend upon the local climatology and meteorology. Before erecting a cooling tower, engineers should calculate the climatological effect of the additional moisture bur­den in the air.

brungs. It comes down to balancing aerological and ecological changes against aquatic and ecological changes. If a plant is in the Ohio River Valley where the summer humidity is quite high at night, fog would easily be created. But, in other, less humid areas, this would occur rarely using cooling towers or some other cooling facility.

Someone asked earlier if there is an advantage to putting the heat into the atmosphere rather than into water. It seems to me that in many cases the effect would be the same because the water, in turn, heats he air. The power industry has done many studies which indicate that heat can be lost quickly, in a matter of a mile or two downstream; thus, the heat is basically lost to the atmosphere. This does not allow for the hu­midity increase attributable to cooling towers. Does it really make much difference whether the heat goes directly to the atmosphere or through the stream and then into the atmosphere?

hubbert. The last annual report of the aec (Fundamental Nuclear Energy Research, 1968, January 1969, p. 41) stated the temperature in­crease in the Columbia River persists for a hundred miles or more down­stream in contrast to the mile or two. However, the heat eventually goes to the atmosphere because there’s nowhere else it can go. Before deciding to distribute it to the atmosphere in concentrated form at the plant or to feed it to the atmosphere over a wider area, one should know what at­mospheric thermo pollution amounts to at the plant. Intuitively, I suspect immediate release at the plant would be far less objectionable than heat­ing the river.

audience. Rivers cool themselves by evaporation of moisture into the air. Whether heat is passed into a tower or into a river, it eventually moves in the form of water vapor to the air. Incidentally, a cornfield 9 miles square would evaporate moisture dining the day at a rate equal to a million-kilowatt plant.

abrahamson. These considerations with regard to cooling towers are reflected, I believe, in the cost estimates that were previously given?

bray. Yes, they appear as capital costs and operating costs. Also, any pumps or fans associated with the cooling towers would increase costs. I’m not familiar with the design of cooling towers, since it falls out­side any scope General Electric has as a supplier. I believe that was in the Federal Power Commission report (see Hosmer’s paper, p. 139ff).

hubbert. What temperature in the summertime can be obtained in a condenser by using evaporative cooling towers as compared with using the Mississippi River at this latitude? The thermodynamic efficiency of a steam engine depends only upon temperatures of the boiler and of the condenser.

bray. The rise in temperature through main condensers is on the order of 10-15° F. Thus, the temperature of the incoming coolant, which is generally river water, is increased 10-15°. A greater rise might come from a cooling tower, depending upon how effective the cooling tower is.

audience. I have reviewed approximately 90 per cent of the cooling towers of reactors in the eastern United States and have found no record­ing of any fogging problems. I would like to ask Congressman Hosmer if he knows of specific incidents where fogging has been a problem?

hosmer. An environmentalist from New York told me about this at South Dakota State University in Brookings one night.

ramey. I cannot provide any references on the problem of fogging, but I understand that this question was raised in connection with some of the New England reactors. By the way, if salt water were to be used in cooling towers, agriculture might be affected. In Florida, for example, the question of building cooling towers for plants has been thought to be a rather touchy one because of the possibility that the salty fog might ad­versely affect the valuable truck crops raised in some areas.

freeman. Waste heat in the quantities discharged by large power plants into rivers is definitely a problem. The Federal Water Pollution Control Administration, in cooperation with the states, has established standards for all rivers to limit the increase in the temperature rise in the rivers. The problem occurs most acutely in the summertime, when the rivers have low flow and are naturally hot. The quantities of heat injected by either a fossil fuel or a nuclear plant of the size being built today, pre­sent a severe local problem and, in many cases, cooling towers are re­quired to meet the present standards of the Water Quality Act. There are a number of questions surrounding this problem, a major one of which is what size of mixing zone is permissible at particular locations. It is gen­erally accepted by the people who deal with water quality that ejecting

the heat into the atmosphere is definitely preferable to ejecting it into the rivers.

The ultimate answer to this problem is neither cooling towers nor ejecting heat into the river. We badly need to improve the efficiency of generating electricity. Electricity is, at present, an inefficient method of converting our energy resources into a usable form. The most efficient methods now barely reach 40 per cent. The aec’s research program to perfect a breeder reactor that will operate at higher temperatures and pressures is an important part of the search for greater efficiency. We should be devoting funds to researching magnetohydronamics which promises to give us a method of converting energy into electricity at near 60 per cent efficiency rather than 40 per cent efficiency; this effort has been badly neglected. Heat can be beneficial when nuclear plants can be located in cities; it can be used directly for heating and cooling. Heat is not inherently something bad, but a by-product that could be useful. How­ever, the idea that it can be dumped into waterways without risk is er­roneous.

abrahamson. I have a written question in two parts: First, given the current state of the art and any imminent developments, to what extent is it possible to remove radioactive contaminants from both gaseous and liquid wastes? Secondly, what would be the cost rates of doing both to the maximum extent?

bray. In my paper (pp. 3-26) I have identified some techniques that have already been used to bring radioactive release below standards. Gaseous wastes can simply be kept in the plant longer. This technique takes advantage of the half-life of the material, and can be improved just by keeping the gas still longer. Although the technique is effective to a certain degree, the half-lives of some gases are months or years. A second technique for reducing off-site effects of gaseous wastes is the use of ele­vated releases. For liquids, there is the technique of using filtration, ion exchange, or evaporation to take out the radioactive components from the liquid; the amount removed depends on how far the processes are taken. Equipment worth some $3-5 million is used to attain the levels currently being released; costs of lowering the levels further are on the order of $ 1-2 million per factor of ten or so. Solid wastes are stored in radioactively shielded containers or tanks and shipped off-site.

audience. If society were to change its values, and decided that the increased treatment of wastes was desirable, to what extent does current technology enable us to actually do so?

bray. Again, you can do more of the same — hold gases longer, filter or otherwise treat liquids more. The stopping point depends on how min­119

uscule this release should be relative to background radioactivity. Other techniques are being explored, such as recombiners; since much of the nonradioactive gaseous waste can be recombined, doing so early would make the hundreds of feet of piping now on-site more effective because the radioactive gas can then be kept longer.

audience. As I understood Dr. Tamplin’s calculation of doses re­lated to maximum permissible exposure, higher exposures to human be­ings come about because of various ecological considerations. Yet Dr. Auerbach pointed out that in spite of many studies, it appeared that the ecological build-up from discharges of radioactivity was very low. There appears to be a discrepancy there.

tamplin. I don’t think there was really any discrepancy between Dr. Auerbach’s and my points. If I understood him correctly, he was talking about the effects of effluents on the ecological system, exclusive of man. The studies which he had conducted and which people at the University of Washington and at Hanford had conducted, were looking at the effects of effluent on the ecology, exclusive of man. These studies detected no noticeable changes in ecology. Now, I wanted expressly to show that one can start with the quantities of individual radionuclides released to the en­vironment and rigorously calculate the dosage that would end up in the tissues of man. From there, you can determine the effect of that dosage. In the example that I used, I simply picked a release rate. From what I’ve heard from the reactor experts in this discussion, the release rate that I picked was a factor of a million higher than what is actually released from the reactors. If, indeed, the lower figure is the present release rate, then the dosages that the reactor experts were quoting would be identical with what I would calculate. The numbers which I presented in my paper would be the upper limits, because I made a number of conservative as­sumptions about unknowns in the biological data. I am still left with some uneasiness. If the law of the land were something different than the mpc values in Title 10 —if it specified a definite quantity of, say, cesium re­lease as the absolute maximum — I could have based my calculations on that quantity. I had to pick a hypothetical release rate because I didn’t have precise information on the quantities of the individual radionuclides.

auerbach. Dr. Tamplin is quite correct. I did not address myself at all today to the problem of ecological concentration. This is an entirely different area, in which there is a great deal of misinterpretation of the facts available. Ecological concentration cannot be generalized to a par­ticular group of organisms or individual species in a particular habitat; it must be evaluated on the basis of particular isotopes. One cannot general­ize that there will be ecological concentrations of 105 or 10e in the en­

vironment. There are certain unusual situations in which one may find high ecological concentrations — a typical example of such unusual con­centration is found with phosphorus, an element which is needed by all organisms. The more peculiar and unusual elements — such as cesium, cerium, ruthenium, and promethium — tend to have much lower ecologi­cal concentration factors. Consequently, any calculations made on the basis of human hazard have to be made carefully. In many of the rivers that have been examined, the extent of human hazard can be ascertained on analysis of the water, both for its radioisotope content and its specific activity. In many cases, one can predict the concentration on the basis of the ratio of the specific activity in the water and in the food organisms.

tamplin. It is true, as Dr. Auerbach says, that there are a great many uncertainties as one proceeds from the release of particular radio­nuclides to determining what concentration will end up in man. The ap­proach I reported produces the numbers that are upper-limit estimates of the dosage. I can say in a scientifically defendable way that the dosage will not exceed this number, and, indeed, it should be less. Faced with un­certainties in trying to give a scientific number, the only valid scientific number that we have is an upper-limit number; the actual hazard or the actual concentration will be expected to be less than this number.

lieberman. Dr. Tamplin’s conceptual approach involving the as­sessment of exposure to man from specific radionuclides is in order, and I would not argue with the arithmetic of his calculations, but I agree that his assumptions with respect to the quantity of radioactive material released to the rivers is off by a large factor. He used a hypothetical quantity of fis­sion products generated in one hour of operation of a 500-megawatt plant, but the actual amount released from operating reactors is 10e less than that. The data from our study at the Dresden Nuclear Power Station in­dicates that for 137Cs, where the ratio for release in liquid waste in the ac­cumulation of the fuel was the highest, the estimated release for a year’s operation was 0.17 Ci and the calculated accumulation for 600 mega­watts for one year with a 64 per cent use factor was 4.6 x 105 Ci, giving a ratio of 3.7 x 10~7. Similar ratios for all other radionuclides were ap­preciably lower. In general, the actual ratio based on operating experience of commercial nuclear power stations is only about 1 part in 100,000,000, considering the longer-lived fission products. Accordingly, the results of the dosage calculations Dr. Tamplin indicated would be off by an ex­tremely large factor. Dr. Berad Kahn, who is responsible for the study summarized in my paper and who measured release values from the Dres­den plant on a specific radionuclide basis, used an approach consistent with Dr. Tamplin’s, assessing each individual radionuclide released to the environment.

One other point on which there might be some confusion relates to the federal regulations. Besides addressing themselves to concentrations of radioactive material at the point of discharge, there are provisions in the regulations which require taking into account the effects of possible concentrations of radionuclides in the environment — for example, in the food chain — when evaluating man’s exposure.

tamplin. That provision does exist within Title 20, but the law or the wording should be more specific. It would be possible to set limits on the amount of cesium that is going to be released from a reactor and, if there were 15 or 20 reactors within an ecological region, to set the ulti­mate criterion before a single reactor is built. Then, if the releases the re­actor puts out meet the law, they will not exceed the frc guidelines.

eisenbud. I could get more excited about Dr. Tamplin’s calculation if it weren’t for that factor of a million, which is a substantial factor. In actual circumstances, we are dealing with very small amounts of radio­activity. The question is, How hard should one look, or how hard should one work in terms of effort, money, and manpower to define human doses when they are below a certain value? For example, in New York there’s about a 15 per cent difference in the annual dose rate, equivalent to 10 to 12 mrad/yr, between the sandy shores of Brooklyn and the igneous rock of upper Manhattan. This being the case, it’s hard to get a health depart­ment excited about defining the dose from rivers with any degree of pre­cision when, by the roughest approximation, you can establish beyond any doubt that the dose is less than 1 mrad/yr.

audience. Dr. Tamplin, can you show us how you arrived at your assumptions?

tamplin. I came at them in a rather straightforward way, consider­ing the background of my introduction into the nuclear energy area. In the Lawrence Radiation Laboratory, much of my work has been asso­ciated with the Plowshare Program. There, we talk about kilotons and megatons, so I originally based my example on a kiloton; then I was ad­vised that no one would understand what a kiloton was. So I recalculated it, to find that it was the same amount of activity that was produced in 1 hour of operation of a 500-megawatt thermal plant, the assumption I stated on pages 45^46. After giving the example, I said that no one should take it at face value, that it was not intended to be a scare tactic. I wanted to come up with a scientifically defensible estimate of the effects of a nu­clear reactor on the basis of the quantities of each radionuclide released to the environment. I assumed a hypothetical river and plant; if I had had the individual radionuclides that were to be released, I would have used them, or, if the law were specific, I would have used the legal limit. I couldn’t use the vague statement in Title 10 or the table of mpc values. So, I picked a number, which I hope is high by a factor of 10е. If it is, I don’t know what this discussion is all about.

audience. What is the present practice and what are the plans for storage of high-level wastes?

auerbach. The aec has announced a long-term program to develop various techniques for the storage of high-level wastes with long half-lives. It is my understanding that high-level wastes are currently stored under­ground in tanks at two or three of the main aec installations. The tanks are large 800,000-gallon refrigerated gunnite, concrete, or steel. The long­term plans for high-level wastes include a number of possibilities, one of which is converting the radioactive high-level liquid to a solid and per­haps storing it in such places as abandoned salt mines. Salt mines appear to offer a unique capability for high-level waste storage for the following reasons: There is an enormous number of salt mines throughout the United States. They are deep underground and, in some cases, thousands of feet thick. They have some favorable characteristics, such as dryness and plasticity. If a cell were created in the salt for these materials, it would tend to be self-sealing. For the past 7 or 8 years, a number of aec labor­atories, mine included, have proceeded cautiously on the testing of the salt mines for the ultimate storage of high-level wastes. A salt mine in western Kansas has been used, and the results look favorable. In fact, at the present time, one fuel element is being tested in storage in these cham­bers 2,000 feet below ground.

ramey. The aec announced in June 1969 a policy of requiring all high-level wastes to be solidified and stored at a federally owned repos­itory, which would probably be a salt mine.