In the first century, the Egyptian astronomer Ptolemy theorized that the earth is the center of the universe and everything revolves around it. Near­ly two thousand years later, Ptolemy is alive and well. Despite the fact that he reportedly died in the second century, despite the fact that his theory supposedly was buried by Copernicus, despite the fact that man has now circled the earth and set foot on the moon, we still believe everything re­volves around us. At least we act that way. We act as if man were supreme over nature instead of a part of nature. We act as if man were the only thing that counts. We act as if our environment held no influence over our life, our mind, or our spirit. Consequently, we hack at the land, rip through natural resources, wipe out animals, dump trash, foul the air, and pollute streams.

Recently, it was determined that every person in the United States produces annually some 1,800 pounds of waste. Even more frightening is the inadequacy of facilities to dispose of these man-made mountains. The Public Health Service reports that 90 per cent of the dumps in the nation are potential sources of disease and pollution. The Hudson River is al­ready so polluted that the U. S. Geological Survey reports serious danger of polluting aquifers (water-bearing strata of permeable rock, sand, or gravel). If such pollution intensifies, it would make the river useless as well as endanger deep-well pumping. Last year, sixty faculty members of the ucla Medical School recommended that anyone not compelled to re­main in Los Angeles leave immediately for the sake of his health.

I do not mean to criticize New York or California. In the last few years, they have been most active states in the fight against pollution. Per­haps that is what is so frightening. There is no assurance that billions spent can ever resurrect a dying resource. Hence, we must not be con­servationists alone — we must become preventionists.

Preventing environmental problems is both cheaper and healthier than attempting to solve them. With that philosophy in mind, my admin­istration is moving on every front to preserve and protect natural re­sources in Minnesota. To protect the land, we have worked to create the Voyageurs National Park, which would maintain the unique natural assets of northern Minnesota. There can be no doubt that the establishment of a national park is a long process. The sustained support of the Minnesota Conservation Federation and all others concerned about protecting natu­ral resources will continue to be most necessary. After meeting in Wash­ington with the Vice President, the director of the Budget Bureau, and the President’s staff, I am encouraged. I believe we are finally seeing light at the end of the tunnel in the struggle to secure support for the park from the Nixon administration.

To prevent loss of lives and land, we have been managing flood­plains. We are reclaiming mines to determine their recreational possibili­ties. We are spending $7.5 million to acquire and develop parks and trails. We are developing a conservation curriculum for the schools, grades 1­12. Thanks to increased license fees, we have been able to spend $1.1 mil­lion to improve deer, waterfowl, and fish habitats.

We need a broadbased land improvement program. We must never forget that the land does not belong to us; rather, we belong to the land.

However, we must go beyond correcting the sins of yesterday. To those who say pollution is the price of progress, I say nonsense. To those who say wait to see what the federal government and other states will do, I say we haven’t got the time. The current example of our dedication to the principle of immediate action is the state’s controversy with the Atomic Energy Commission over water pollution below a nuclear power plant. But that is not the only case where Minnesota wants the right to be more aggressive than the federal government in pollution control. We are one of half a dozen states in the nation to be actively working against in­adequate, ugly, and unsanitary dumps — the federal government has no standards for solid waste management. In the summer of 1969 we went beyond national boundaries to protect Lake Superior by calling an Inter­national Joint Commission — any long-range solution to the preservation of this lake must include Canada. At the same time, we are cooperating fully with the federal government in the recent conference held about the lake; I have instructed the immediate implementation of the interim rec­ommendations made by the conference.

In another instance, Minnesota has protected itself in case the federal government does not act. The state legislature passed my Crystal Waters Program, part of which includes a state incentive for local sewage treat­ment plant construction. The projects are financed by local and federal funds, but the state’s incentive becomes important if the federal govern­ment fails to appropriate the full amount of money authorized. President Nixon has recommended $214 million for this program. The House has passed a bill nearly tripling that figure; the Senate has not yet acted. The Federal Water Pollution Control Agency has notified the Minnesota Pol­lution Control Agency that the state program is approved, which means that a minimum of $4 million was released for the construction of local sewage treatment facilities. When Congress adopts its final appropriations, that sum may be increased. Minnesota communities are waiting to learn the amount of federal funds before drawing on state resources, but if needed, the state stands ready to help.

Again, in 1968 Minnesota adopted air quality standards on ten cate­gories of pollutants. When federal regulations (dealing with only two cate­gories) came out, they permitted a lower minimum than the state stand­ards do.

With that record of action, there should be no doubt that as long as I am Governor, Minnesota will insist on its right to protect the lives and health of its citizens in the best way it knows how. This is part of the pro­gram I had in mind two years ago, when I said, “It is important for the state to take the initiative in pollution control. It would indeed be unwise and unfortunate if the federal government preempted the management of our air and our land and our water. Successful management needs the co­operation of the federal government with the states supplying the leader­ship. The states should, and this state will.”

One request we do make of the federal government: federal-state revenue sharing. We need money to do the kind of job that needs to be done. With the federal government sitting on the most lucrative source of revenue — 93 per cent of ah income taxes paid in the country — it has the capacity to return a share to the states. Minnesota needs this additional resource to pursue the campaign for environmental excellence. We must go beyond correcting past mistakes. Money, action, and some intensive thinking is in order.

We must look at population distribution and be aware of its results. For several years, Minnesota has been trying to reverse the rural-ur­ban migration because small towns cannot afford the loss, cities cannot tolerate further congestion, and our natural resources cannot support higher densities of people. Good results have emerged from a concerted effort to stabilize the population balance.

We must start some long-range planning for environmental manage­ment. The State Planning Agency is cooperating with the University of

Minnesota on an extensive analysis of present environmental problems and potential problems. The scope is broad, covering the topics of air, water, food, chemicals, waste-heat, new species, and so on. This working analysis could be extremely valuable in determining what needs to be done now and how future problems can be avoided.

We must get local officials more involved in conservation programs, as well as keep the general public actively involved in solving conserva­tion problems. In an attempt to do this, I support regionalizing the opera­tions of the conservation department. Regional headquarters could serve as multi-use facilities — being an administrative arm of the department, holding educational programs for the public, and having demonstration projects to acquaint the people with new approaches.

I see three controls available to curb pollution: formal legal controls, economic controls, and informal or attitudinal controls. Thus far, we have put most of our efforts into formal legal controls. Although that is certain­ly necessary and proper, pollution is far too important a threat for us not to use every possible weapon to combat it. Economic controls to protect the environment are pathetically weak — in the sense of dollars alone, it is economically more advantageous to pollute in the short run than not to pollute. But business must be made to see that pollution abatement results in economic advantages in the long run. Some industries already suffer economic losses from pollution, and the agriculture industry loses an es­timated $500 million a year in crop damage. On the other hand, some companies are in a position to make profits from recovered waste. All companies must come to regard pollution control as one of the costs of doing business. In Minnesota, the industrial community has created a pol­lution section in their statewide organization; this section has excellent po­tential to provide education as well as internal enforcement.

Yet, in the final analysis, informal controls are the most effective. Legal controls usually set minimums; by themselves they cannot inspire higher performance. Economic controls can be applied only to one seg­ment of the economy. Informal or attitudinal controls can make things happen. Ultimately and ideally, in a democratic society all restraints should be based on the people’s acceptance of what is permissible. Right now, polluting is socially acceptable. A few government leaders, a few businessmen, a few labor leaders, and a few citizen groups are moving against pollution. But there are 200 million people in this nation, 3 and 3A million people in this state. And generally, Americans still have not matured in their attitude toward pollution. As a people accustomed to un­equalled wealth, unexcelled growth, undefeated ambitions, unlimited hor­izons, we simply have to learn that there is only so much — only so much air, only so much land, only so much water. The pioneer days of ruining, packing up, and moving on are over. There are limits. And we have nearly reached them.

Meanwhile, legislators and planners work on pesticide regulations to prevent poisoning of the planet, and the housewife writes to support the ban on farm applications but not on her garden sprays.

They draft lakeshore regulations to prevent or correct lakeside slums and dying lakes, and homeowners ask them to penalize the big polluters instead of the hundreds of little ones.

The garbage in this nation is accumulating so fast that an entire state could be buried under ten feet of rubbish. But citizens won’t take two min­utes to return bottles to the store — and if the current trend in their tastes continues, they may no longer even be able to purchase any but “dispos­able” containers.

Our problem is eloquently described by Pogo: “We have met the enemy and they are us.” Yes, we are the polluters, and the mess is ours to clean up. Every citizen in this country must join in the effort both to compensate for past errors and to prevent them from recurring. All 200 million should commit themselves to the statement, “I give my pledge as an American to save and faithfully to defend from waste the natural re­sources of my country.”

Harold LeVander
Governor of Minnesota

November 6,1969

In the accompanying tabulation are listed the several sources of information underlying the maximum permissible exposure level from external sources of radiation (by this phrase, I mean radiation sources external to the body). The primary source of data for man has been the

medical uses of radiation, particularly radiology installations. Secondary sources of data in man are the doses clearly associated with definite changes. These come from radiation therapy and occasional accidental exposure, and could be considered as providing a ceiling for any exposure. A “floor” is provided by the background radiation levels which Dr. Eisen — bud and others have discussed earlier in this volume. These data in man are supplemented and augmented by animal experiments. Long-term studies have been supported over the last twenty years — many of them by the Atomic Energy Commission and the Public Health Service, some by state laboratories and others — to provide assistance in situations where data for man cannot be obtained.

Source of Data Human exposure

Primary: radiology installations over past 40 years.,

Secondary: doses associated with definite changes Secondary: background radiation levels “floor”

Animals

Large number of long-term experiments…………………….. assistance and

range-finding

The primary human data useful for determining maximum permis­sible exposure levels for individuals are derived from experience with radiologists and other radiation workers. Retrospective analyses have been made of the radiation levels in many installations of the 1920’s and even of World War I. Where there had been no effects in long-term employees, the levels so estimated were judged to be “safe.” On the other side of the coin, changes incidental to the use of radiation in patients and also the exposures of the Japanese and to a lesser extent the Marshallese have contributed human data where effects are seen clearly. Thus, working down from levels where effects are seen and correlating the “safe” radi­ology installations with these give a first approximation of maximum permissible dose (mpd). Because the data pertain always to the exposed individual, these levels are pertinent only to somatic effects — not to ge­netic effects.

The chart on page 92 shows, similarly, sources of information for maximum permissible exposure to radioisotopes. Here again, human ex­perience is rather considerable. The luminous dial painters and radium workers, many of them having worked from the time of World War I onward, have supplied clear evidence of effects which can be correlated with their body burden of the isotope. The radium patients differ from the radium-dial painters, luminous-dial painters, and radium workers in some details. These patients received radium as a nostrum in the late twenties

Basis for Maximum Permissible Exposures to Radioisotopes

Source of Data Provides

Human exposure

Luminous dial painters, radium workers, and

radium patients…………………………………………………. Reliable and

relatively complete picture

Patients receving isotopes in therapy………………….. Assistance

Accidental exposures including calculated and measured effects or fallout from nuclear

weapons tests…………………………………………………….. Primarily inferential

assistance except

Animal experiments

Several long-term experiments…………………………….. Important influence

“Metabolism” of isotopes…………………………………….. Essential

Empirical toxicity ratios……………………………………… Important influence

Calculations from external radiation data………………… With the metabolic

data provide majority of figures except for bone seekers

and early thirties, when radium was considered a rather general “tonic”; they received pure radium and its daughters, not a mixture as did the dial workers.

Accidental exposures provide another level of human experience. And finally, the levels for many radioisotopes are determined by calcula­tion from external radiation figures by the use of data on the metabolism (i. e., tissue distribution and excretion) of the isotope using as the basis a “critical” organ (ordinarily, the one with the highest concentration of the radioisotope). Thus, standards for radioisotopes are determined in part by direct observation and in part by experience in the external radiation field. This has led to something of a “double standard,” one applying primarily to the bone seekers, the other to soft tissue seekers. Work with animals provides directly empirical toxicity data, the approach of the pharmacologist extrapolated into the field of radiobiology.

On page 93 there appears an abbreviated and incomplete summary, taken largely from experimental work, of the doses of radiation associated with detectable changes in a number of important biological processes. In most cases the dose at which effects may possibly occur is given as well as the dose at which they clearly occur. The purpose of this survey is to show that in only one or two instances are clear effects seen (sometimes

"The doses are reasonably well established in the animal experiments, but the transfer of information from animal to man introduces a factor of uncertainty which depends on the process under consideration. With the human data the ef­fects are clear but dosimetry is more approximate — for example, the dose must be calculated on the basis of deposition of a radioisotope, must be reconstructed in the case of the Japanese and the radiologists, and so forth. Nonetheless, they show the relation of current mpd’s to those at which overt somatic changes occur. ” Pertains to potential somatic effects only. Not intended to be more than illustra­tive.

“ Dosimetry difficult but correct within an order of magnitude.

4 Estimated long-term cumulative dose.

‘ Dosimetry reconstructed and had components of both low and high linear energy transfer radiation; is very approximate. f Very dependent on dose rate.

in a single exposure) at dosage levels approaching those discussed in this volume as representing the mpd levels. The lowest is that associated with minimal changes in the morphology of the circulating lymphocyte, a change which may or may not be regarded as “damage.”* * Dosimetry for these particular experiments was difficult. Nevertheless, the error would be unlikely to be sufficient to bring the doses appreciably higher than other “sensitive” processes in the table.

This summary could be misleading. Many of these are doses at which something is seen clearly after a single exposure. What we are interested in in setting mpd’s is at the other end of the scale — very low levels of ex­posure over long periods of time. Here there are two important con­siderations.

First, is fractionation of the dose important in developing the somatic effects of radiation? Clearly, it is. Fractionation of the dose will decrease effect if recovery can take place between exposures. On this premise, a total dose of much more than the single dose can be withstood without even noticeable effect if the dose is sufficiently fractionated. Since a total dose which is lethal if given in a single exposure is easly withstood, in terms of acute effects, if protracted, the presence of recovery is quite gen­erally assumed to occur with the somatic effects of radiation. But there are exceptions: radiation of high linear energy transfer rates —such as that associated with neutron exposures, alpha particles, fission fragments — does not seem to exhibit the marked effect of dosage fractionation seen with X or gamma radiation. Also, we know little about the presence or absence of recovery in those processes with long latent periods such as carcinogenesis.

The second important question is whether or not somatic effects in general follow a “threshold” relation to dose. This is illustrated in the accompanying figure. In many cases, the effects, especially acute, short­term ones, do appear to be related to dose, as in the line marked threshold in the figure. But the incidence of cancer, leukemia, and genetic changes (to be discussed later) may follow a non-threshold relation to dose, as in

the second line of the figure. With genetic effects such as mutating the evidence is clear. For the others there are still differences of opinion.

Application to Nuclear Reactor Problems

What does all of this have to do with the subject of this volume, nu­clear power and the public? Considering still only somatic risks to the in­dividual, I shall examine first exposures at relatively high levels of radia­tion.

Tidal power is similar to the more familiar water power of streams except that the flow in streams is unidirectional, whereas that of the tides reverses four times per day as tidal basins are alternately emptied and filled. Although large tidal projects such as that proposed for Passama — quoddy Bay on the Maine-New Brunswick boundary have been under consideration for nearly half a century, the first such plant, that in the La Ranсe estuary in France, with a planned capacity of 320 megawatts, be­gan operation in 1966.

In the USSR, a small plant of 400 kilowatts in the Kislaya Inlet, 80 kilometers northeast of Murmansk, began operation in 1968, and much larger installation of 320 megawatts is planned for the Lombovska River on the northeast coast of the Kola Peninsula.

Large-size tidal-power plants are possible only in a limited number of favorable localities around the world. These require a combination of a large tidal range and a bay or estuary capable of being enclosed by dams. A summary of such localities, and the tidal power potentially obtainable is given in the tabulation below (sources: Bemshtein, 1961; 1965, Table
5-5, p. 173; Trendholm, 1961). The total capacity of all of the sites amounts to about 64,000 megawatts. This is about the same magnitude as the world’s geothermal-power capacity, but only about 2 per cent of the world’s potential water-power capacity, and an even smaller fraction of the world’s power needs. Tidal power, nevertheless, is capable in favora­ble localities of being developed in large units, and it has the further ad­vantage of producing a minimum disturbance to the scenic and ecological environment. Hence, there are many social advantages, and few disadvan­tages, in developing tidal power wherever practicable.

Average Potential

Now that I have discussed natural radiation levels, existing regula­tions, and design objectives, attention can be directed toward radioactive waste disposal systems themselves. They are, in general, provided to collect potentially radioactive wastes, process them, and discharge them in a safe and economical manner.

Gaseous Waste System. In arriving at the design of the gaseous waste system which has been used as a standard for many years, designers in­cluded several factors in order to meet General Electric’s design objec­tives. For example, assume that a nuclear power plant without these design features released enough radioactivity over a year to result in a whole — body gamma dose of 500 mrem (the aec limit) to a man standing at the power plant site boundary. From this assumed beginning, the design of the gaseous waste system was improved by adding a holdup capacity which delays the release of the material for a specified period of time and allows much of the radioactivity to decay before release. This equipment addition reduced the assumed 500 mrem to about 50. A stack about 300 feet high and twice as high as any nearby structure was then also added, further reducing the off-site effect by another factor of about 10. This brought the design close to the design objective of 5 mrem/yr. In other words, there is a design that not only meets today’s regulations, but further minimizes radioactive release and meets a design objective well below the federal limit.

What are the principal sources of radiation which result in these small off-site doses? In a nuclear power plant the process of producing steam creates some waste materials in the form of gas. About 90 per cent of this gaseous waste consists of oxygen and hydrogen, which are not radioactive. Most of the remaining 10 per cent consists of nitrogen, which is not radioactive either. A small portion, however, consists of some radio­active nitrogen and oxygen and various forms of krypton and xenon, a fraction of which are radioactive.

In a conventional bwr plant the steam, with its small percentage of radioactive gas, goes through the turbine and into the condenser. In the condenser the steam is converted back into water and the water is returned to the reactor in a closed process system. Some of the radioactivity stays with the condensate. The remaining air (including the radioactive gases) is drawn out of the condenser to create a near vacuum. These gaseous wastes are then passed into a delaying storage system which reduces the radioactivity in oxygen and nitrogen to minor amounts; the amounts of radioactivity in the xenon and krypton are also reduced. Next, the wastes are passed through a filter, which removes any solid radioactive particles. The gases are then dispersed to the environs through a stack or vent pipe which is generally about twice the height of the nearby buildings.

These gases, before passage out of the stack, are monitored continu­ously to measure at all times the amounts being emitted. The monitoring equipment is provided with automatic alarms to tell whenever the emis­sion is reaching preset limits.

Liquid Waste System. The actual facts about the radioactivity of liquid wastes from a nuclear power plant are perhaps even more reassuring than are the facts about wastes released to the atmosphere. But in this case, too, the facts are easier to accept if one knows what the wastes con­sist of and how they get into the water — and if one considers the question in some meaningful perspective.

Radioactive liquid wastes originate with a number of planned opera­tions within the power plant. The wastes are kept separated enough to achieve the best treatment method and to recover as much water as prac­tical for re-use in the plant. More than 80 per cent of the liquid wastes are thus recovered and reused — therefore, never released from the plant.

The essential purpose of the liquid radioactive waste system is to remove radioactive material from the waste water. This is achieved by filtration, ion exchange, and in some cases evaporation. These treatment methods essentially move the radioactive materials from the liquid (water) to a solid or concentrated form.

Some of the liquid wastes contain impurities which make them un­suitable for reuse in the plant, which requires very high purity water. Such wastes include those from the plant laundry, chemical laboratory,

and floor drains. The amounts of radioactivity in these are small, con­tribute only a small increment to natural background radioactivity, and so are planned for environmental discharge. Before such discharge, how­ever, each batch (tankful) is analyzed to determine that it does meet the required criteria for discharge. Wastes not meeting such criteria are re­turned for reprocessing. Thus, no discharges are made which are not well within allowable conditions. Any water which is discharged is mixed with the effluent cooling water at a rate to ensure good dispersion.

Monitors on the waste discharge line provide continuous information about the concentrations in the liquid waste. Further, samples of the dis­charge are routinely collected from the canal and analyzed to give a composite of all activity discharged from the plant.

Solid Waste System. The solid waste system collects the radioactive solids resulting from processing of liquid wastes and from water purifying in the plant. Most of the radioactive material present in wastes leaves the plant via this route. All of these materials are encased in steel barrels and stored temporarily within the plant facilities. When a sufficient number of barrels accumulate, they are shipped to an AEC-approved site.

Therefore, with respect to the systems which handle the gaseous, liquid, and solid waste, there is a demanding design basis, a conservative approach to allowable releases, and finally a condition in which the de­signers have been provided a safe design. Systems were added to far exceed the effort necessary to just meet existing regulations. Liquid and solid release are completed under controlled operations.

I am not, therefore, optimistic that, short of a major overhaul in the aec’s basic approach to licensing of nuclear power plants, the decisions on nuclear power licensing will reflect an appropriate balancing of real risks against real benefits. The licensing program has been studied and restud­ied, but these studies have all centered upon the single objective of stream­lining the process to benefit the license applicants. There has been no study of the program from the standpoint of the interests of potential in — tervenors. Indeed, although the nuclear power industry has been fully represented on these study groups, not a single person likely to represent the interests and views of conservationists or environmentalists has been appointed to any such group. Such a study is needed. Meanwhile, there are a number of small steps which would help to some extent. Most impor­tant would be the development of a more objective attitude on the part of the aec regulatory staff. The staff’s safety analysis should explicitly recog­nize the risks, what is being done to minimize them, and most important, the risks which remain despite the safeguards built into the plant. These factors should also be developed by the aec staff counsel at the hearing. It would help also if the aec adopted a more benign attitude toward inter — venors. Intervention should be permitted at any time after the license ap­plication has been filed. Hearings should be scheduled so as to give an in — tervenor at least two months to prepare between the time he is admitted as a party and commencement of the hearings. There should be some flexi­bility in the conduct of the hearings themselves so as to permit the inter­venor’s counsel, without prejudice to his client’s interest, to absent himself from portions not of particular interest to him, thereby enabling some cost-saving. And aec should make daily transcripts of the hearing avail­able to the intervenors without cost upon an appropriate showing of the intervenor’s poverty.

Such improvements would undoubtedly increase the elapsed time be­fore construction permits are issued, but it is extremely doubtful that in­terventions would result in denial of construction permits even under such

more liberal procedures. But more effective interventions would serve a salutary purpose in helping to focus public attention on the risk/benefit calculus and how it is performed. This might serve to bring about a more informed public opinion which could be reflected to Congress.

A second area of risks of nuclear plants is those relating to environ­mental effects. As with all means of meeting our growing energy needs, there is no way that environmental effects can be eliminated completely. The real challenge is to ensure that they are well enough understood and kept as small as possible consistent with meeting our energy and other needs.

Those who have been concerned about these matters have long rec­ognized the need to minimize the environmental effects associated with energy usage. The Interdepartmental Energy Study for example, con­cluded that: “In the future, development and use of fuel resources will be strongly influenced by the urgent necessity to control critical increases of environmental pollution — such as automobile exhaust gases, S02 and other products of fossil fuel burning; excessive heating of rivers and estu­aries by powerplant water cooling; acid mine drainage; radioactive wastes; and damage to scenic and land values through mining. Research and de­velopment programs aimed at both the assessment of hazards to health

and environment and the economical abatement of damages are urgently needed.” (“Energy R&D and National Progress: Findings and Conclu­sions,” September 1966.)

Information from plant operating experience available over the past years has shown that nuclear power plants discharge relatively small quan­tities of radioactive wastes to the environment. The Bureau of Radiologi­cal Health has compiled most of these discharge data obtained both by plant operators and by state health agencies. In developing plans for a co­ordinated national surveillance program, consideration should be given to the publication of this type of data in a uniform manner in a journal such as Radiological Health Data and Reports. The recent studies at operating facilities by the Bureau referred to earlier confirm that the discharge of ra­dioactive effluents into the air and water environment have not produced radiation levels at these facilities that would result in significant radiation doses to the population. The Bureau will, however, continue to assess these sources of environmental radiation to determine both short — and long-term levels and make estimates of their radiation effects on man.

From a public health standpoint, a major purpose of environmental surveillance programs, as noted earlier, is to obtain data that are useful for assessing the radiation exposure to man. The identification of the critical radionuclides and pathways for these nuclides to reach man generally re­quires that relatively few environmental media be analyzed in order to es­timate population exposure from the operation of a nuclear power plant. For this reason, the Bureau of Radiological Health is considering the fea­sibility of a graded environmental surveillance system which is based on a detailed knowledge of the effluent released. Studies have demonstrated that detailed analysis of the plant effluents can be quite meaningful, where­as it is difficult, if not impossible, to detect radioactivity in the environ­ment that has resulted solely from plant operation. Under such a concept, detailed and frequent field monitoring of radionuclides outside the plant boundary would be dependent on the level and kind of effluent released, except for continuous monitoring of the critical pathway for that particu­lar nuclear plant. The use of an integrating dosimeter to measure the ex­posure owing to the release of noble gases would be an example of the continuous monitoring required. In addition, a basic monitoring program such as that given on page 64, might be conducted on a periodic basis in order to keep the surveillance system operable.

Although the previous discussion has been concerned with surveil­lance requirements for the environment, it should be noted that the dis­charge of radioactivity to the environment from nuclear facilities is regu­lated by the aec so that the levels leaving the controlled area will not ex­ceed concentrations established in Title 10, Part 20 of the Code of Federal Regulations (10CFR20). In the case of liquid effluent, average concen­trations in the condenser water cooling canal must stay within these limits. The concentrations will be further diluted as the canal flows into the re­ceiving stream. For gaseous discharges, the discharge rate is normally con­trolled such that average concentrations in the atmosphere will not exceed 10CFR20 limits at the site boundary. Thus, increasing the flow rate of air discharged from the stack will lower the discharge concentration, but will not affect the total quantity of radioactive material discharged to the en­vironment or the resultant exposure of the population in the vicinity of the site.

The world’s requirements and resources of industrial energy are large and complex subjects which, owing to limitations of space in the present vol­ume, can only be summarized. However, this summary is based upon two more extensive reviews (Hubbert, 1962; 1969) to which reference may be made for more detailed information and documentation.

Flux of Energy on the Earth

The use of energy for nonbiological or industrial purposes can best be appreciated in the context of the earth’s total matter-and-energy econ­omy. In this context, the earth may be regarded as a material system whose gain or loss of matter during the last billion years has been negligi­ble. Into and out of this surface environment, however, there occurs a con­tinuous flux of energy, in consequence of which the earth’s material con­stituents undergo continuous or intermittent circulation.

The principal sources of this energy are: solar radiation, geothermal energy conducted and convected to the earth’s surface from the earth’s hotter interior, and tidal energy derived from the combined gravitational and kinetic energy of the earth-moon-sun system (see accompanying tab­ulation). Of these three sources of energy, that from solar radiation is overwhelmingly the largest. Heat from solar radiation is received at a rate of 2 gram-calories per square centimeter per minute. Converted to power units, this amounts to a radiation of thermal power at a rate of 0.139

Source

Solar radiation. Geothermal heat Tidal energy…

watts/cm2, and the total power intercepted by the earth’s diametral plane amounts to 17.7 X 1016 watts. This is about a hundred thousand times the world’s present installed electric-power capacity. By comparison, energy inputs from geothermal and tidal sources amount only to about 32 x 1012 and З x 1012 watts, respectively.

Geothermal energy occurs initially as heat, which eventually assumes the lowest temperature of the earth’s ambient surface environment. Tidal energy is dissipated into heat by the friction of tidal currents in the oceans and in the shallow seas, coastal bays, and estuaries around the world. Of the solar energy input, about 35 per cent is directly reflected into outer space (see accompanying tabulation). Of the remaining energy, about 42 per cent is absorbed and converted directly into heat. Another part is ab­sorbed by the atmosphere and the oceans, causing thermal expansion and providing the energy for atmospheric and oceanic circulation, and about 23 per cent becomes the latent heat of evaporation of water. This, to­gether with atmospheric circulation, is responsible for the hydrologic cy­cle, including the precipitation and runoff of water on all of the land areas of the earth. Finally, a small fraction (less than 1 per cent) of the total in­put of solar energy is captured by the leaves of plants and is stored as chemical energy in the process of photosynthesis whereby inorganic ma­terials such as 02, C02, and H20 are converted into organic compounds and provide the energy base for the entire plant and animal kingdoms. Upon decay, the organic matter of plants and animals oxidizes, and the stored chemical energy is released as heat.

The rate of decay of organic material is almost exactly equal to its rate of production. However, a minute fraction of this material may be­come deposited in sedimentary muds or in peat bogs in an oxygen-free en­vironment and thus be preserved. The accumulation of this small fraction of preserved organic matter over the last 600 million years of geological history has resulted in the world’s present supply of fossil fuels — coal, pe­troleum and natural gas, and related materials.

The end product of all of the terrestrial energy transformations, ex­cept for the fraction of solar energy directly reflected and the minute frac­tion preserved and stored by organisms, is degradation ultimately into heat at the lowest ambient temperature. This heat then leaves the earth by spent, long-wavelength, thermal radiation.

One additional form of terrestrial energy is that stored in atomic nu­clei, particularly in the heavy elements uranium and thorium, and in the light element hydrogen. Uranium and thorium have an abundance in the surface rocks of the earth of about 16 parts per million, and are slightly radioactive. By this process, nuclear energy is being spontaneously con­verted to heat, which appears to be a major source of the earth’s geo­thermal energy. The extraction of the stored nuclear energy from both the heavy and light elements by artificial means is the basis for the recently acquired ability to produce nuclear power.

From this brief review, it is seen that the energy sources appropriate for large-scale industrial uses must be either the earth’s supplies of stored energy: the fossil fuels, nuclear energy, and to some extent geothermal energy; or else the various channels of the energy flux: solar power, water and wind power, plants and animals, and geothermal and tidal power. With regard to the stored energy, the problem of present interest is prin­cipally the magnitudes of the supplies, and about how long they can be depended upon to provide a major fraction of the world’s potential re­quirements. For the contemporary energy fluxes, the problem is the mag­nitude of the industrial power that can be derived from each.

With the dawn of Dresden and Yankee nuclear power plants around 1960, this nation saw nuclear energy as a major future contributor to power generation in the United States. As it became obvious that the power needs of the United States would continue to grow, and that there was some limit to fossil fuel supplies, nuclear power generation became a major consideration in power plans in the United States. Recent concerns, such as that with environmental contamination, reinforced this turn to nuclear power.

The major considerations associated with the part nuclear power plants would play in national power plans involved not only the feasibility and economic justification of nuclear application, but also, and principal­ly, the safety of nuclear reactor power plants.

The purpose of this paper is twofold. A typical nuclear power plant will be described in order to demonstrate that the various technologies in­volved in the design, construction, and operation of nuclear power plants are well known today and available to industry. We are not dealing with an unknown. Nuclear power plants can be and have been efficiently and safely built and operated. The design philosophy for safety will be de­scribed in detail to demonstrate that these nuclear power plants are being designed, built, and operated by a technically competent industry. The in­terests of the public are considered.

Acute exposures would be important only in the event of a major disaster in which the reactor was essentially destroyed and its contents of radioactive material released to the environment. This would almost certainly involve forces external to the installation, such as a major earth­quake, total failure of all safety features, or hostile forces either from without or within, including an internal conspiracy. Recovery of the or­ganism from these acute effects would be almost complete if the individual survived, although there is a finite risk of a small residuum of irreversible damage.*

The immediate or early effects of such acute exposure would involve primarily the blood-forming organs, the gastrointestinal tract, skin, and if the dose were very high (>1,000 rads total body exposure) the central nervous system. These are threshold responses so far as can be ascer­tained, and recovery is complete except for the small fraction of irrepa­rable injury, f There is a fourth — or fifth-order risk of a long-term delayed effect after such an acute exposure. The long-term risk is the development of leukemia or other forms of cancer, cataracts, and possibly accelerated incidence of the degenerative diseases of old age.

The doses at which these acute effects occur are many times higher than those associated with maximum permissible population or occupa­tional exposure. They are mentioned here because any general discussion of the problems of nuclear power generation must consider them, however * The presence of an irreversible component in radiation exposure may be basi­cally different from the biological effects of most other agents in our environment. The irreversible component may range from a few per cent or less with X or gamma irradiation to as much as 50 per cent for neutrons and 70-80 per cent of the total effect with alpha particles and other high linear energy transfer radi­ations.

tThe risk of long-term effects might be based on the fraction of irreversible in­jury, but this is not usually done except in considering nonspecific effects such as shortening of the life-span. Processes with long latent periods may or not be linked to the “irreversible” component.

unlikely the maximum credible accident. It is not my role as a biologist to estimate the probability or improbability of such an event. The reactor engineers do this and relate it to the probability of other major catastro — phies in our technological civilization.