Krypton - 85 in the Atmosphere: Accumulation, Biological Significance, and Control Technology (Ncrp Reports Ser. : 44)

NCRP REPORT No. 44

KRYPTON-85 IN THE ATMOSPHERE-AccumuIation, Biological Significance, and Control Technology

Recommendations of the NATIONAL COUNCIL O N RADIATION PROTECTION AND MEASUREMENTS

Issued July 1, ,1076 National Council on Radiation Protection and Measurements 7910 WOODMONT AVENUE/WASHINGTON, D.C. 20014

Copyright @ National Council on Radiation Protection and Measurements 1975 All rights resewed. This publication is protected by copyright. No part of this publication may be reproduced in any lform or by any means, including photocopying, or utilized by any informat~onstorage and retrieval system without wntten permission from the copyright owner, except for brief quotation in critical articles or reviews. Library of Congress Catalog Card Number 76-11458 International Standard Book Number 0-913392-26-x

Preface This report of the National Council on Radiation Protection and Measurements (NCRP), successor to the National Committee on Radiation Protection and Measurements, is concerned with the accumulation and biological significance of 86Krin the atmosphere, and the possible techniques available for its control. 8%r is relesased to the atmosphere through nuclear weapons tests and the generation of nuclear power. With the cessation, for the most part, of atmospheric testing of nuclear weapons, 86Krin the atmosphere results primarily from the reprocessing of nuclear fuel, very little s6Kr being released from the actual operation of the nuclear power plants themselves. This report estimates the future global concentrations of 85Kr in the atmosphere resulting from projected future levels of nuclear power use, the absorbed doses to man resulting from these concentrations, and possible techniques which may prove pract,icable for the future control of E6Kratmospheric levels. The present report was prepared by the Task Group on sSKr of the Council's Scientific Committee 38 on Waste Disposal. Serving on the Task Group during the preparation of this report were: MERRIL EISENBUD,Chairman Members

ROYE. ALBERT KENNETHCOWSER D. GOWBERQ EDWARD JOSEPHA. LIEBERMAN LESTERMACHTA C. UPTON ARTHUR

The Council wishes to express its appreciation to the members and consultants for the time and effort devoted to the preparation of this report. LAURISTONS. TAYLOR President, NCRP Washington, D.C. March 6, 1976

contents Preface . . . . . . . . . List of Tables . . . . . List of Figures . . . . . 1 Introduction . . .

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1.1 General Remarks . . . . . . . . . . . . . . . . . . . . 1.2 Properties of Krypton and 86Kr . . . . . . . . . . . . 1.3 Sources of 86Kr . . . . . . . . . . . . . . . . . . . .

2

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Estimates of Future Power Requirements. 86KrReleases and e6KrInventory . . . . . . . . . . . . . . . . . . 2.1 2.2

3

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Future Power Requirements . . . . . . . . . 86Kr Generation and Inventory to the Year 2000

The Fate of

Discharged to the Atmosphere

3.1 The Oceans ns a Sink for 86Kr 3.2 Washout and Deposition of 86Kr 3.3 Atmospheric Dispersion of 86Kr

4

. Dosimetry 4.1 4.2 4.3 4.4 4.5 4.6

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Dose from Photons Produced in a Semi-Infinite Cloud Dose from Bremsstrahlung Produced in Air or Skin . . Dose from 8bKrin the Body . . . . . . . . . . . . Dose from Beta Rays in an Infinite Cloud . . . . . . Dose from 8%r in the Airways of the Lungs . . . . Summary of Doses . . . . . . . . . . . . . . . .

Projected 86KrConcentrations

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5.1 esKr Concentrations . . . . . . . . . . . . . . . . . . 5.2 Projected Population Dose Commitments . . . . . . . .

6

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The Biological Significance of the Absorbed Dose . . . . 6.1 6.2 6.3 6.4

Genetic Effects . . . . . . . . . . . . . . . . . . . . Overall Carcinogenic Effects . . . . . . . . . . . . . . Carcinogenic Effects on Skin . . . . . . . . . . . . . . Possible Interaction of Ionizing and Ultraviolet Radiation .

1

~i 7

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CONTENTS

Status of 86KrRemoval from Waste Gases

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7.1 Adsorption a t Ambient Temperature . . . . . . . . . . 7.2 Cryogenic Adsorption . . . . . . . . . . . . . . . . 7.3 Cryogenic Distillation . . . . . . . . . . . . . . . .

7.4 Selective Absorption . . . . . . . . . . . . . . . . . . 7.5 Permelective Membranes . . . . . . . . . . . . . . 7.6 Clathrate Precipitation . . . . . . . . . . . . . . . .

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8 Discussion . . . . . . . . . . . . . . . . . . . . . . 9 . Summary . . . . . . . . . . . . . . . . . . . . . . APPENDIX A . Calculation of Long-Term Air Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX B . Phantom Description . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . The NCRP . . . . . . . . . . . . . . . . . . . . . . . . NCRP Reports . . . . . . . . . . . . . . . . . . . . . . . Index

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40

List of Tables 1. Primary radiations from 8bKrdeca,y . . . . . . . . . . . . 2. Secondary radiations from s6Kr decay .. .. . . .. . . 3. Projections of annual electric energy generation in the United States . . . . . . . . . . . . . . . . . . . . . . . . 4. Cumulative installed nuclear electric power capacity in the United States . . . . . . . . . . . . . . . . . . . . 5 . Projection of electric power generating capacity in the world. . 6. Cumulative installed nuclear electric power capacity in the world . . . . . . . . . . . . . . . . . . . . . . . . 7. Assumed nuclear reactor mix and world accumulation of s6Kr in year 2000 . . . . .. .. . . .. .. . . .. .. 8. Estimated production and accumulation of 86Krin world nuclear power economy . . .. .. . . . . .. .. .. 9. The oceans as a sink for S6Kr . , , . , . . . . . . . . . 10. World population weighted concentration from uniform release rate of 1 curie of 85Krin 1 year . . . . . . . . . . . . 11. Percentage of separable adipose tissue and nonfat tissues and the Ostwald coefficient for subdivisions of the human body. . 12. Equilibrium absorbed dose rate to body organs per unit air concentration from immersion in a semi-infinite cloud of 86Kr . . . . . . . . . . . . . . . . . . . . . . . . 13. Comparison of equilibrium absorbed dose rates to body organs per unit air concentra.tion from immersion in a semi-infinite cloud of 8bKr . . . . . . . . . . . . . . . . . . . . 14. Estimated world population dose commitments from annual worldwide reIeases . . . . . . . . . . . . . . . . 15. Several processes available for 85Kr off-gas treatment . . . . .. . . A-1. Phase 4 average surface air concentration of 86Kr

vii

List of Figures 1. Decay scheme of 86Kr . . . . . . . . . . . . . . . . . . 2. Atmospheric 86Kr concentratio~lsfrom weapons testing and . . . . . . . . . . . . . . . . plutonium production 3. Energy spectrum for scattered photons . . . . . . . . . . 4. Depth dose in tissue from beta radiation . . . . . . . . . . 5 . Concentration of 86Kr measured in northern hemisphere air samples . . . . . . . . . . . . . . . . . . . . . . 6. Predicted average concentrations and annual skin dose equivalent rates due to 86Krin the atmosphere . . . . . . . . A-1. Mean annual surface air concentration contours (10-20 Ci/ma) for the release of 1 Ci/y of 86Kra t Morris, Illinois (Phase 1) . . . . . . . . . . . . . . . . . . . . A-2. Mean annual surface air concentration contours Ci/m3) from Phase 2 . . . . . . . . . . . . . . . . A-3. Mean annual surface air concentration contours Ci/m3) from Phase 3 . . . . . . . . . . . . . . . . . . . . . . . . . . B-1. Legs and male genitalia of phantom

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1. Introduction 1.1 General Remarks The projected rapid growth of the nuclear power industry necessitates a careful assessment of any related potential for environmental pollution. 86Krreleases deserve special attention because of the inherent difficulty in their control and their essentially nonreactive and mobile nature in the atmosphere. The purpose of the present report is to estimate the future global concentrations of 86Kr, their potential significance, and possible techniques for their control. Projections of SGKraccumulations will be made to the year 2000, as this is now sufficiently close to permit reasonable approximations to be made of the world's energy requirements and the extent tro which they will then be fulfilled by nuclear power reactors. On the other hand, the year 2000 is sufficiently far off to allow for periodic reappraisal of the projections of 86Kr accumulation in relation to developing information about the biological effects of this nuclide and the technology for control of 86Krreleases. In addition to the global projections, the present report also includes estimates of S6Kr concentrations near nuclear fuel chemical reprocessing plants. Problems associated with S6Krdisposal have been previously reviewed by Kirk (1972), Dunster and Warner (1970), Coleman and Liberace (1966), Diethorn and Stockho (1972), Karol et al. (1971), and Bryant and Jones (1973).

1.2 Properties of Krypton and 86Kr 1.2.1 Chemical Properties.

Krypton is one of the class of noble gases which includeshelium, neon, argon, krypton, xenon, and radon. These are colorless, tasteless, and in general, chemically inert. I n recent years, however, they have been shown to be capable of entering into ionic or covalent bonding with highly reactive elements such as fluorine or oxygen. Bartlett (1962) reported a chemical reaction between xenon and HE' yielding XeF4.The first report 1

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INTRODUCTION

of a chemical rewtion involving krypton came from Grome et al. (1963), who reported the production of KrF, from a mixture of krypton and fluorine through which an electric discharge had been passed a t 86OK. Later work, however, indicated that the resultant compound was K r F z (Schreiner et al., 1965), a white crystalline solid which sublimes a t temperatures well below 273"K, but which can be stored for several weeks a t dry ice temperature (195'K) without appreciable loss. Recently, the crystal structure of KrFa has been investigated by low temperature x-ray diffraction techniques (Burbank et ad., 1972). Noble gases, including krypton, have been shown to enter into compounds called clathrates (Lindquist and Diethorn, 1968; M c C l a i and Diethorn, 1964; Balek, 1970; Chernick, 1967) in which the noble gas atoms are physically entrapped in molecular cages of hydroquinone, or other organic compounds. In addition, the noble gases have been shown to be highly soluble in nonpolar solvents (Steinberg and Manowitz, 1958) with this solubility increasing with decreasing temperature (Nichols and Binford, 1971). The solubilities of the various noble gases are related as Rn > Xe > Kr > Ar > Ne > He.

1.2.2 Physical Data. The Handbook of Chemistry and Physics (Wesst and Selby, 1971) and C~:ryogenic Reference D d a (Union Carbide Corp., 1967) give the following values for physical constants of krypton: Atomic number = 36 Atomic weight (naturally occurring) = 83.80 Melting point = - 156.6'C (116.6"K) Boiling point = - 152.30 & 0.1O0C (120.85 f 0. 10°K) Triple point = - 157.Z°C, 548.2 mm Hg (116.0°K, 73.09 kPa) Critical point = - 63.8OC, 4.12 X lo4mm Hg (209.4'K, 5.49 MPa) Density = 3.733 g/l heexisting burden of skin cancer. In order to understand better the implications of long-term 8SKrreleases to the atmosphere, epidemiological and laboratory studies should be undertalcen to define the nature and degree of interaction, if any, of W radiation with ionizing radiation in the induction of skin cancer.

7. Status of "Kr Removal from Waste Gases The extent to which S6Krfrom reactor operations or reprocessing of irradiated fuels can be controlled will depend on the availability of equipment to remove 86Krfrom the various effluents. Slansky et al. (1969) examined the characteristics and costs of the several processes available for krypton holdup and recovery. IIis results are summarized in Table 15. All processes except those involving entrapment by clathrates have been found to remove more than 90 percent of 86Kralthough, as he points out, pilot plant scale experience was limited and was nonexistent with several processes. Also, the capital and operational costs listed for a threc metric ton per day plant can only be considered approximations, since sufficient information was not available to make detailed cost comparisons. Slansky (1971) subsequently updated his review of the separation processes for noble gas fission products, adding considerable details on each process. His tabular comparison of processes remains essentially unchanged (with only the addition of electrostatic diffusion) and he again emphasized that detailed cost comparisons require more data (Slansky, 1971). These cost estimates may escalate depending upon the need for such things as redundant process lines, extensive pre-purification of the gas, and additional containment structures. I n a more recent survey, Nichols and Binford (1971) also summarized the development status of processes that are potentially applicable for holdup or decay of krypton and xenon. The results of their survey are in agreement with thosc of Slansky and their summary which follows, provides a brief elaboration of all but one of the processes included in Table 15.

7.1 Adsorption at Ambient Temperature

The adsorption of noble gases on charcoal or molecular sieves a t ambient temperatures is the process that has been studied most extensively 40

7.2 CRYOGENIC ADSORPTION

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41

(Slansky, 1971;Nucleonics Week, 1971a). This method is effective for interim holdup of xenon and krypton because selective adsorption and desorption causes these gases to move much more slowly through a packed bed than the air or other carrier gas. The process is not suitable for recovery of krypton and xenon since it does not provide for withdrawal of a concentrated product. In short, this method is suitable for delaying the release of waste gases for a period s&cient to allow for decay of the shorter-lived nuclides of the noble gases. It is not effective for control of sSKr. The primary disadvantage of room temperature adsorption is that very large bed volumw are required to provide appreciable holdup. Also, a fire hazard exits from the use of charcoal, which has low thermal conductivity, in an environment that includes oxygen and heat production by radioactive decay. The use of molecular sieves, typically inorganic zeolite-type (metal alumino-silicate)materials, avoids the fire problems, but the materials are expensive and require the use of beds that are two to four times larger than charcoal beds of comparable holdup ability. The ambient-temperature adsorption process has been used in a number of U.S. research reactors and has been in use since 1966 in the KRB reactor in Germany. Another power reactor in Germany has used this system since 1968, and a third German reactor using this system is due to come on line. The German company that markets the system can fumish a charcoal system that will reduce t,he radioactivity of BWR effluent by a factor of 2000 by providing three days of holdup for krypton and 70 days for xenon (Nucleonics Week, 1971a). Such a system for an 1100-MW electric power BWR requires five cha.rcoaJ tanks, each 1.8to 2.7 meters in diameter and 15 meters long. Somewhat smaller and less bulky charcoa.1 absorption systems that provide radioactivity reduction factors up to 200 are available.

7.2

Cryogenic Adsorption

Adsorption on charcoal at liquid nitrogen temperatures permits the use of a smaller adsorption bed and is adaptable for recovery of krypton and xenon by a process of temperature cycling (Wirsing et al., 1970; Offutt and Bendixsen, 1969). This process for recovery of -ton and xenon was demonstrated on a large scale at the Idaho Chemical Processing Plant (ICPP) about 15 years ago. Because the beds are cooled and heated alternatively, the refrigeration costs are very high. Other disadvantages are the fire hazard and the possibility of explosion of hydro-

42 /

7. STATUS OF

REMOVAL FROM WASTE GASES

Permselective membranes Clathratt! precipitation

99 per cent

Bench scale work only; no engineering UnLaboratory studies known only; engineering tests needed

mKr is collected aa a storable solid

Membranes sensitive t chemical High power costs Needs concentrated feed gas Crystallization step slow

1500

'

200

Not trvnilable Not available

A11 of the processes for the removal of 86Kr from off-gases from nuclear fuel reprocessing plants require some pretreatment of the dissolver gas except possibly the selective absorption process. The cost data presented are for a plant which processes three metric tons per day of uranium. Comparative costs for alternatives to off-gas treatment for the control of radioactive stack emissions are available. For instance, disposal of the gases to ground reservoirs would require a capital cost of $345,000 for a plant of the same size, and operating costs would range between $75-100 per metric ton of uranium. Facilities for the storage of tho off-gas during meteorological conditions unfavorable for safe atmospheric dispersal would cost $1 million and operating costs could run t o $100 per metric ton of uranium, depending on the length of storage time. The most drastic alternative, shutdown of the plant during unfavorable conditions, would involve a loss of $15,000-$30,000 per metric ton of uranium capacity for the duration of the S ~ I U ~ ~ O W ~ .

Adapted from Slansky et at., 1969. [Reprinted with permission from Environmental Science and Technology 3. 446 (1969). Copyright held by the American Chemical Society.]

2 $'

d0 M

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7. STATUS O F

REMOVAL FROM WASTE GASES

carbons, nitrogen oxides, and ozone (produced by irradiation of oxygen). The system also requires prior removal of gases that would freeze a t liquid nitrogen temperatures and plug the adsorbers. The disadvantages of the cryogenic system are such that it cannot now be recommended for recovery of krypton and xenon, but the process does have potential application for interim holdup of effluent gases.

7.3 Cryogenic Distillation

Cryogenic distillation provides an effective, continuous, small-size system for separation of gases based upon their relative volatility (Offutt and Bendixsen, 1969; Nucleonics Week, 1971b; Holmes, 1971). This type of process is used commercially for isolation of the components of air a.nd is being used intermittently to remove radioactive xenon and krypton from an off-gas stream at ICPP. The process is capable of recovering krypton and xenon in a relatively pure form suitable for direct bottling in gas cylinders. A serious concern in this process, particularly when applied to a fuel reprocessing plant, is the explosion hazard that results from the presence of ozone or mixtures of liquid oxygen with hydrocarbons and nitrogen oxides. The L i d e Division of the Union Carbide Corporation has a contract to supply cryogenic distillation systems for 99.9 percent recovery of noble gases from the effluent of three BWR units at the proposed Limerick station. I n addition, they have designed a cryogenic distillation system for use in the proposed Newbold Island plant (Nucleonics Week, 1971b). Cryogenic distillation is considered to be one of the more promising processes for krypton and xenon recovery.

7.4 Selective Absorption The study of the separation of noble gases from air streams by adsorption in (or extraction by) chlorofluoromethanes has progressed to the nonradioactive pilot plant stage at the Oak Ridge Gaseous Diusion Plant (Merriman et al., 1970; Stephenson et al., 1970). The system is versatile, continuous, and adaptable to scaleup. It also appears to be considerably less subject to fire and explosion than the previous processes. Primary questions that remain to be resolved in further development work relate to the tolerance of the system to con tarn in ant,^ in the off-gas streams, the effects of radiation damage on the solvent, and corrosion

7.6 CLATHRATE

PRECIPITATION

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45

problems that may result from the evolution of fluorine and chlorine. Selective absorption is a promising method for recovery of krypton and xenon from both reactors and reprocessing plants.

7.5 Permselective Membranes The permselective membrane process for recovery of krypton and xenon from air has been investigated on the laboratory scale a t Oak Ridge National Laboratory (Rainey et al., 1971). This process, which is based upon selective permeation of gases through silicone rubber membranes, operates at ambient temperatures but requires differential pressures across the 0.7 mil (0.18mm)-thick membranes of as much as 50 psi (0.34 MPa). The process requires many stages for effective separation. A workable large-scale process would require the development of a method for packaging the membranes to densities of several hundreds of square feet (-30m2) of active membrane area per cubic foot ( 4 . 0 2 8 ma) 3f volume. The economic viability of the process would require a very large production of membranes to reduce substantially its price below the present value of $10 per square foot (930 cm2). Some questions wilh respect to the radiation stability of the membranes for some reactor applications also remain. The Oak Ridge National Laboratory development tvorli on this process has been curtailed in favor of the fluorocarbon absorption process.

7.6 Clathrate Precipitation The precipitation of noble gases from organic solvents as solid clathrates has been investigated on a laboratory scale (Keilholtz, 1966-1967; Clark and Blanco, 1970). The process requires prior absorption of the krypton and xenon in an organic liquid at a pressure of about 1000 psi (6.89 MPa). The clathrates form very slowly, even a t these high pressures, and are known to be decomposed by radiation and heat. The clathrates, as well as all of the known compounds of krypton, are unstable at temperatures higher than about 50°C (327°K). At present this process can be regarded as little more than a laboratory phenomenon. In the future it may have application to the solidification of radioactive noble gases for storage.

8. Discussion The biological significance of the 8% accumulation is the basic factor that should influence policies governing the extent t o which release of 86Krto the general atmosphere should be reduced. I t has been shown that fuel reprocessing plants will be the main source of this nuclide. Minor amounts will issue from the reactors of the world, but i t appears that this will be far less than 1 percent of the total. Thus, as an interim policy which should certainly be suitable for the next ten years, the releases from reactors can be given lower priority and attention directed at the fuel reprocessing plants. Research and development programs of practical systems for the removal of 85Krare making progress, and prudence would seem to dictate that the fuel reprocessing plants be equipped with 85Kr removal systems as soon as the technology is practicable. The significance of the projected doses to human populations, for the levels of 85Xr discussed above, cannot be evaluated with confidence because of a lack of information on the biological effects of low levels of radiation. Well-designed experiments must be conducted during the next decade to add to our present knowledge. The most pressing issue is whether the build-up of 85Krwill increase the incidence of skin cancer in the world's population. The projected skin dose will average about 2.0 mrem/y by the year 2000 and could be 10 to 100 times higher by the year 2050, assuming that all 86Kr in gaseous wastes from the nuclear industry is not contained, but is released to the atmosphere. By the year 2050, the sldn dose from 85Krcould thus begin to approach the exposure received from the external component of natural radiation, which averages about 75 mrem/y. Since skin cancers are the most common form of neoplasm, it would seem worthwhile to undertake epidemiological studies of the incidence of skin cancer in otherwise comparable populations exposed to different levels of ionizing radiation. There are wide variations, from 60 mrads/y to several hundred mrad/y (Eisenbud, 1973). Additionally, hundreds of thousands of radiation workers (Klement et al., 1972) annually receive whole-body doses several times greater than the absorbed dose from natural background. The question of whether there might be an interaction between ultraviolet radiation and ionizing radiation is one which can be answered in 46

DISCUSSION

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47

studies on experimental animals and it is recommended that such research be initiated. I n this report the subject has been addressed from the point of view of the United Statea atomic energy program. It is estimated that by the year 2000, the United States installed nuclear electric power capacity will be about 1000 GW compared to nearly 5000 GW for the world. Any policy adopted by the United States would thus deal with about 20 percent of the B6Kr generated in the year 2000. This is clearly a general question that requires careful international collaboration and the NCRP urges that the International Atomic Energy Agency and the International Commission on ~ o l o g i c a Protection l give prompt attention to the need for developing policies that will be acceptable on an international scale.

85Kris a beta-emitting fission product with a half-life of 10.7 years. Because of the characterietic inertness of the noble gases, this radionuclide tends to accumulate in the atmosphere with the concentration at any given point being determined by the rate at which it is introduced to the atmosphere, by meteorological diffusion, and by radiological decay. Neither the oceans nor the land surfaces act as significant sinks. Naturally-occurring 85Kr due to spontaneous fission of uranium and cosmic ray-induced atmospheric reactions occurs only in insignificant traces, and has been overwhelmed in recent years by production of this nuclide in weapons testing, reactor operation, and fuel reprocessing. The principal sources of 86Kr to date have been production of plutonium for military purposes and the atmospheric testing of nuclear weapons. I t is estimated tha.t approximately 5 megacuries of 86Krwere introduced into the atmosphere from weapons testing between 1945 and 1962. Plutonium production in the United States introduced about 15 megacuries as of 1966, by which time the process was sharply curtailed. Additional 85Kr has been contributed by plutonium production in other countries. Emission of 85Krfrom the nuclear fuel cycle will increasingly become the dominant source of this nuclide. Emissions from operating reactors are and will continue to be insignificant compared to the releases from fuel reprocessing plants. I n the absence of emission control, the 86Kr content of the atmosphere can be expected to increase for the remainder of this century and beyond due to the burgeoning nuclear energy industry. An additional source of 85Kr may be the utilization of nuclear explosives for peaceful purposes. Depending on one's assumptions as to the size of the nuclear power program and the types of reactors to be utilized, it is estimated that the atmospheric inventory of 8% by the year 2000 from reactors throughout the world will be between 3600 and 6200 megacuries. The dose to humans results from their immersion in the atmosphere containing 85Kr. The critical organ is the skin, with the dose to the gonads and whole body being lower by orders of magnitude. I t is estimated that the skin dose from ddiffused in the atmosphere in 1970 was about 0.02 rnrem/y, and that it will increase more than one hundredfold to about 3 mrem/y by the year 2000. This assumes no efforts to control 48

SUMMARY

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49

releases of the 86Kr. The whole body dose is estimated to have been 2 X mrem in 1970 and may increase to 0.02 rnrem/y in the year 2000. 86Krcan be eliminated from gaseous waste streams to the extent of 98-99% by several processes now in various stages of development. These include fluorocarbon extraction, cryogenic distillation, low ternperature adsorption on charcoal or silica beds, use of selective membranes, and precipitation as a clathrate. The most pressing question is whether the low level skin dose resulting from the build-up of 86KrwiU increase the incidence of skin cancer in the world's population. I t is not possible to answer this question unequivocally, but the sldn has proven to be a relatively radioresistant organ and it is significa.nt that an increase in skin cancer has not been observed among the Japanese atomic bomb survivors. The dose from 86Kr for the next several years will be of such a low order as to preclude the need for installation of recovery systems. Rowever, as such systems become available for full-scale application, their installation in fuel reprocessing plants should be considered in relation to the costs of such installations and the benefits, if any, that would result.

Calculation of Long-Term Air Concentrations The f i s t phase deals with the f i s t 6 hours of plume travel, or distances to about 100 km. A local wind-rose is used to assign material emitted during the year to directional sectors in proportjon to the frequency with which the wind blows into each sector. In the second phase climatology of air trajectories is used to estimate the dispersal of source material for travel times up to 5 days and distances up to a few thousand kilometers. The third phase deals with the remainder of the k s t plume paasage around the earth (about 30 days). In this phase an effective diffusion coefficient (time dependent) is used to estimate the lateral spread of the plume about an average trajectory derived from clirnatological flow patterns in the lower atmosphere. This trajectory carries the plume from the east coast of the U.S.across the Atlantic to Europe, Asia, the Pacific and back over North America. The fourth phase (beyond 30 days) involves a computer model of global diffusion in which uniformity around circles of latitude is assumed. During phase four, there is continued dilution due to north-south and upward mixing. It is estimated that after about two years, the 85Kr becomes nearly uniform throughout the atmosphere, so that subsequent concentration changes are due almost entirely to radioactive decay. Mean annual pollutant concentrations are combined with demographic data to estimate population exposure for each phase and total worldwide population lifetime exposure. To illustrate the use of the model, we will assume a hypothetical nuclear fuel reprocessing plant in lllinois with 8 uniform release rate of 1 Ci/y of 86Kr. In this example, air concentrations resulting from 1 year of operation (total release of 1 curie) are calculated. Realistic estimates for an actual plant can be obtained by multiplying by the actual emission rate (Ci/y).

In this earliest phase of plume travel, a local wind rose is used to determine the horizontal distribution of the average annual concentration 50

CALCULATION OF LONG-TERM AIR CONCENTRATIONS

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51

a t ground level. Material emitted continuously throughout the year is assigned to each sector in proportion to the frequency of time during which the wind direction lies in the sector. The vertical distribution of material is given by a half-Gausian distribution whose mean is at ground level; the standard deviation (a,) of the Gaussian curve can be related to the vertical diffusion coefficient as shown below. The standard formula (Turner, 1970) for the mean concentration at. ground level (Ci/ma) from a continuous point source, is

el

where a. K,

=

vertical diffusion coefficient = 5m2/s emission rate = 1 Ci/y = 3.2 X 1F8Ci/s f = frequency of wind in sector fi = mean .wind speed in sector (m/s) e = sector width: 22% degrees or a/S x = distance from source (m) t = plume travel time (s) The value chosen for the vertical diffusion coefficient (K, = 5 m2/s) is considered to be a reasonable day-night, all-weather annual average for the lower troposphere (Machta, 1974). However, there is considerable variability with altitude, season, and weather conditions, and the appropriate mean value is uncertain. Values of ti and f are obtained from wind-rose statistics. The calculated air concentration pattern for the assumed source in Illinois is shown in Fig. A-1.

&

=

=

Phase I The second phase deals with plume dispersion at distances to a few thousand kilometers or several days travel time. At this range, singlestation wind data are no longer applicable and the model uses a climatology of air trajectories to estimate lateral dispersion and long-term concentrations. A computer program has been developed to construct trajectories from historical wind data tapes and calculate air concentrations along each trajectory. For the illustration provided here, trajectories mere calculated 4 times per day for one month out of each season to obtain an approximation of the average annual air concentration. Plume concentrations (Ci/ma) were calculated from

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APPENDIX A

Fig. A-1. Mean annual surface air concentration contours the release of 1 Ci/y of 86Krat Morris, Illinois (Phase 1).

where u

Ci/ma) for

wind speed along the trajectory (m/s) distance perpendicular to the trajectory (m) standard deviation of the plume in the direction perpendicular to the trajectory (rn);[a, in nautical miles (1.852 km) is assumed numerically equal to plume travel time in hours] Other symbols and parameter values are the same as in Eq. (A-1). The computer calculated mean annual air concentration pattern over the United States and Canada is shown in Fig. A-2. =

y

= a, =

Phase 3 The third phase deals with the remainder of the first plume passage around the earth (about 30 days). Mean annual air concentrations are

CALCULATION OF LONG-TERM AIR CONCENTRATIONS

Fig. A-2. Mean annual surface air concentration contours Phase 2.

/

53

Ci/ma) from

calculated from the spread of the plume about a single average trajectory derived from the 12 mean monthly 850 mb wind charts. The annual average concentration a t any point was calculated from Eq. (A-2) as in phase 2 except that for phase 3 it was assumed that a, (nautical miles) = 2 (1) where t is travel time in hours. Actually, available tracer information suggests that u, = t is a good approximation for individual clouds of material (instantaneous releases) (Heffter, 1965). This rate of lateral spread has been arbitrarily doubled to account for the effects of longterm meander of a continuous plume. However, after 15 days of lateral

54

/

APPENDIXA

Fig. A-3. Mean annual surface air con~ent~ration contours (lo-" Ci/ma) from Phase 3.

spread, the growth with time of the lateral standard deviation is stopped to prevent an unrealistically wide north-south spread from 15 to 30 days. A study of the dispersion of computer-calculated trajectories will be used to obtain more satisfactory estimates of the effectivelateral spread of the long-term mean plume during this phase. The average trajectory carries the plume from the east coast of the U.S.across the Atlantic to Europe, Asia, the Pacific and back over North

CALCULATION OF LONG-TERM AIR CONCENTRATIONS

/

55

America, as shown by the dashed centerline in Fig. A-3. Concentrations in the shaded area of Fig. A-3 were calculated in earIier phases.

Phase 4 In the fourth phase (beyond 30 days) concentrations are calculated using a computer model of global diffusion (Machta, 1974). During this period, concentrations are assumed to be uniform around the latitude circles and diffusion takes place only in the north-south and vertical directions. This assumption is also made in other global diffusion models (Karol et al., 1972; MacCracken, 1973). Values of the diffusion coeficients (K, averages 3 X 106m2/s)are varied with latitude, altitude and season in accordance with experience in fitting tracer data on a global scale. Resultant mean annual surface air concentrations for the source assumed in this example (1 Ci of s% emitted uniformly over 1 year) are shown in Table A-1 for 20" latitude bands. As early as the second year TABLE A-l-Phase 4 average surface air concerrtration

Ci/ms) of a6Kr( I C i emitted uniformly over 1 year i n 6&60nN latitude bands) Latitude

Year

'09 70"N

70% 50"N

50"-

30°N

30'10"N

10°N10"s

1030%

30'-

5O0-

505

70's

7O0905

All Latitudes

Year

Average Surface Air Concentration

Year

Average Surface Air Concentration

Year

Average Surface A!r Concentrabon

First year values are acti~allymean annual concentrations from the end of the first month t o the end of one year.

56

/

APPENDIX A

the north-south gradient is very small and after that latitudinal differences are too small to record. Virtually all of the decrease in concentration after two years is due to radioactive decay rather than further dilution from vertical mixing through the model which extends upward to 40 krn. The ma11 annual concentration during the first year, a t a spec8c location is obtained by adding the value from Figs. A-1, A-2, or A 3 (first plume traverse around the globe) t,o the appropriate first year value from Table A-1. For succeeding years only Table A-1 is used.

APPENDIX B

Phantom Description The legs are described by the following inequalities (see Fig. B-l), using the coordinake axes defined in MIRD Pamphlet No. 5 (Snyder et al., 1969):

where the plus or minus sign in the y direction corresponds to the left or right leg, respectively. The testicular region is defined by the following inequalities : -4.8 5 z 5 0 z 1% 100 >= 0

+

+

and

The volume of the genital region, including skin and testes, is 196 cma, and the mass is 194 g. The volume of both testes is 38.6 cma, and the mass is 37.1 g. About 23 cm3of the genital region is skin, a horizontal layer of thickness 0.2 cm and volume 7.2 cm3forming the horizontal base of the genital region in Fig. 13-1, and the frontal skin formed by the layer between the planes z

+ 1%+ 100 = 0

and z 3. 106y

+ 98 = 0

and bounded by

-4.65150

and

-(lO+$)~X510+

but outside the legs, i.e., and 'X

+ Y'

= -X

Z 10

58

/

APPENDIX B

Fig. B-1. Legs and male genitalia of phantom (Snyder el al., 1976).

This frontal skin has a volume of about 16 cm3.Thus, the skin of this portion of the genitalia has a mass of about 23 g. The mass of the region, exclusive of skin and testes, is about (194 - 37 - 23)g = 134 g. Occasionally, the dose to the larger mass of the genitalia minus skin may be useful as an approximation to the dose received by the t ~ tThis . larger region has a mass of 175 g.

References Allied Chemical (1968). Safety Analysis Report: Barnwell Nuclear Fuel Plant, Docket 50332-1, Vol. 1, Chap. 10 (Allied Chemical Nuclear Products, Inc., Morristown, New Jersey) (Division of Technical Information, U.S. Atomic Energy Commission, Washington). BALER,V. (1970). "Radioactive inert gases. Tool for analysis of gases, liquids, and solids," Anal. Chem. 42, 16A-18A; 20A; 22A-23A; %A; 30A-31A. BARTLETT, N. (1962). "Xenon hexduoroplatinate (v) Xe+[Pt Fs]-," Proc. Chem. Soc. 1962, 218. BARTON,C. J., JACOBS,D. G., KELLY,M. J. AND STRUXNESS,E. G. (1971). "Radiological considerations in the use of natural gas from nuclearly stimulated wells," Nucl. Technol. 11, No. 3, 335. BERGER,M. J. (1957). "Calculation of energy dissipation by gamma radiation near the interface between two media," J. Appl. Phys. 28, 1502. BERGER,M. J . (1974). "Beta-ray dose in tissue-equivalent material in a radioactive cloud," Health Physics 26, 1. BERNHARDT, D. C., MOGHISSI,A. A. AND COCHRAN, J. W. (1975). 'LAtmospheric concentrations of fission product noble gases," The Noble Gases, Moghissi, A. A. and Stanley, R. E., Eds. (U.S. Government Printing Office, Washington). BIERI, R. H., KOIDE,M. AND GOLDBERG, E. D. (1966). ' T h e noble gas contents of Pacific seawaters," J. Geophys. Res 71, 5243. BRYANT,P. M. AND JONES,J. A. (1973). "The future implications of some longlived fission product nuclides discharged to the environment in fuel reprocessing wastes," p. 131 in Proceedings of the OECD Nuclear Energy Agency and the ZAEA Spmored Symposium on the Management of Radwactive Wastes from Fuel Reprocessing (International Atomic Energy Agency, Vienna). BURBANK, R. D., FALCONER,W. E. AND SUNDER,W. A. (1972). "Crystal structure of krypton difluoride a t -80°C," Science 178, 1285. BURRIS,L. J. AND DILLON,I . G. (1957). Estimation of Fission Product Spectra in Discharged Fuel from Fast Reactors, ANL-5742 (U.S. Atomic Energy Commission, Washington). CHERNICK,C. L. (1967). The Chemistry of the Noble Gases, Understanding the Atom Series (U.S. Atomic Energy Commission, DTI, Washington). CF~ITWOOD, R. B. (1975). ''The production of noble gases by nuclear fission," The Noble Gases, Moghissi, A. A. and Stanley, R. E., Eds. (U.S. Government Printing Office, Washington). CLARK,W. E. AND BUNCO,R. E. (1970). Encapsulalion of Noble Fission Prod59

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uct Gases in Solid Media Prior to Transportation and Storage, ORNL-4473 (Oak Ridge National Laboratory, Oak Ridge, Tennessee). COLEMAN, J. R. AND LIBERACE,11. (1966). "Nuclear power production and krypton-85 levels," Radiol. Health Data and Reports 7, 615. CULLEN,S. C. AND GROSS,E. G. (1951). "The anesthetic properties of xenon in animals and human beings, with additional observations on krypton," Science 113, 550. W. L. (1972). "The dose to man from atmosDIETHORN, W. S. AND STOCKHO, pheric 8iKr," Hedth Physics 23, 653. DILLMAN, L. T . (1969). Radionuclide Decay Schemes and Nuclear Parameters for Use in Radiation-Dos~Estimation, nm/mird Pamphlet No. 4, J. Nucl. Med. Suppl. No. 2,lO. DILLMAN, L. T. (1970). "Scattered energy spectrum for a monoenergetic gamma emitter uniformly distributed in an infinite cloud," p. 216 in Health Physics Division Annual Progress Report for Period Ending J u l y 31, 1970, ORNL4584 (Oak Ridge National Laboratory, Oak Ridge, Tennessee). DUNSTER. H. J. AND WARNER,B. F. (1970). The Disposal of hroble Gas Fission Products from the Reprocessing of Nuclear Fuel, AHSB(RP)R-101; CONF691039-1; Dep. CFSTI (U.S. Sales Only) UK55 (United Kingdom Atomic Energy Authority, London). EISENBUD, M. (1973). Environmentul Radioactwily (Academic Press, New York). C. A. (1963). "The current FEATE~RSTONE, R. M. and MUEHLBAECEDR, role of inert gases in the search for anesthesia mechanisms," Pharmacol. Rev. 15, 97. FEATACRSTONE, R. A[, SETTLE, W. A N D ALTHOUSE, H. (1975). "Physiology of the noble gases," T h e Noble Gases, Moghissi, A. A. and Stanley, R. E., Eds. ( U S . Government Printing OEce, Washington). Federal Radiation Council (1963). Estimales and E v a l u d i m of F a h u t in the United Slates from Nuclear Weapons Testing Conducted Through 1968, Report No. 4 (U.S. Governnient Printing Office, Washington). A. D.. STRENG, A. G. AND STHENG, L. V. (1963). GROSSE,A. V.. KIRSHENBAUM. "Krypton tetrafluoride: Preparation and some properties," Science 139, 1047. HAYWOOD, F. I?., AUXIER,J. A. AND LOY,E. T. (1964). An Expe-rimenlal I n vestigation of the Spatial Distribution of Dose in a n Air-Over-Ground G m etry, USAEC Report CEX-62.14 (Oak Ridge National Laboratory, Oak Ridge, Tennessee). HEFIVER,J. L. (1965). "The variation of horizontal diffusion parameters with time for travel periods of one hour or longer," J. Applied Meteorol. 4, 153, No. 1. HENDRICKSON, M. M. (1970). The Dose from 86Kr Released lo the Earth's Atmosphere, USAEC Report BNWL-SA-3233-A (Battelle-Northwest, Pacific Northwest Laboratory, Richland, Washington). I~INTERBERGER, H., KONIG,H., SCHULTZ, L. and S u ~ s sH. , E. (1964). "Krypton and xenon in the oceans," Z. Naturf. 19a, 1227.

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"Preliminary observations on the narcotic effect of xenon with a review of values for solubility of gases in water and oil," J. Physiol. 105, 197. LEDERER, C. M., HOLLANDER, J. M. AND PERL~MAN, I. (1968). Table of Isotopes, 6th ed. (Wiley and Sons, New York). L I N D Q ~ ~K.T 0, . AND DIETHORN, W. S. (1968). "Kinetics of rare gas release from hydroquinone clathrates," Int. J . Appl. Radiat. Isotop. 19,333. LOGSDON, J. E. (1972). "Radioactive discharges to the environment from nuclear power facilities," Radiation Data and Reports 13, 117. M. C. (1973). "Zonal atmospheric model ZAM-2," p. 298 in MACCRACKEN, Proceedings of the Second Conference on the Climactic Impact Assessment Program, Nw. 14-17, 1972, U.S. Department of Transportation Report No. DOT-TSC-OST-73-4, Broderick, A. J., Ed. (Department of Transportation, Washington). MACHTA, L. (1974). "Global scale atmospheric mixing," p. 33 in Turbulent Diffusion in Environmental Pollution, Frankiel, F. N. and MUM, R. E., Eds., Vol. 18b of Advances in Geophysics Series, Landsberg, H. E. and Van Mieghem, J., Eds. (Academic Press, Inc., New York). MACHTA, L., FERBER,G. J. AND HEBFTER,J . L. (1974). "Regional and global scale dispersion of krypton-85 for population-dose calculations," p. 411 in Physical Behavior of Radioactive Conlaminants in the Almsphere (International Atomic Energy Agency, Vienna). MARTIN,M. J. (1973). Radioactive Atm-Supplement I , ORNL-4923 (Oak Ridge National Laboratory, Oak Ridge, Tennessee). MCCLAIN,J. W. AND DIETHORN, W. S. (1964). "Thermal and radiation stability of the argon clathrate of hydroquinone," Intern. J. Appl. Radiat. Isotop. 15,151. MEEK,M. E. AND RIDER,B. F. (1968). Summary oj Fission Product Yields for U-296, U-238, Pu-239, and Pu-241 at Thermal, Fission Spectrum and I4 MeV Neutron Energies, APED-5398-A (General Electric Company, Pleasanton, California). MERRIMAN, J. R., STEPEENSON, M. J., PASHLEY,J. H. AND DUNTHORN, D. I. (1970). Removal o j Radioactive Krypton and Xenon from Contaminated OjGas Streams, COW-700816-4 (Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Tennessee). MORROW, P. E., BATES,D. V., FISH, B. R., HATCH,T . F. AND MERCER,T . T. (1966). (ICRP Task Group on Lung Dynamics), "Deposition and retention models for internal dosimetry of the human respiratory tract," Health Physics 12, 173. NAS-NRC (1972). The Ejects on Populations of Exposure to Low Levels of Ionizing Radiation, Report of the Advisory Committee on the Biological EiTects of Ionizing Radiation (National Academy of Sciences-National Research Council, Washington). NICHOLS,J. P. AND BINFORD,F. T. (1971). Status of Noble Gas Removal and Disposal, ORNL-TM-3515 (Oak Ridge National Laboratory, Oak Ridge, Temessee) . Nucleonics Week (1971a). "A radiation decay factor of 2,000 for BWR charcoal filters," Nucleonics Week, June 10, 5.

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SNYDER,W. S., FORD, M. R., WARNER,G. G. AND FISHER,H. L., JR.(1969). Estimates of Absorbed Fractions for Momenergetic Pholon Sources Uniformly Distributed in Various Organs of a Heterogeneous Phantmn, nm/mird Pamphlet No. 5, J. Nucl. Med. Suppl. No. 3, 10. SNYDER, W. S., DILWN, L. T., FORD, M. R. AND POSTON,J. W. (1975). "Dosimetry for a man immersed in an Sinfinite cloud of 86Kr," Tlii Noble Gases, Moghissx, A. A. and Stanley, R. E., Eds. (U.S. Govenunent Printing Office, Washington). SOLDAT, J. K., BRAMSON, P. E. AND PARKER, H. M. (1975). "The dosimetry of the radioactive noble gases," The Noble Gases, Moghissi, A. A. and Stanley, R. E., M s . (U.S. Government Printing Office, Washington). SOUTHWOOD, W. 5'. W. (1955). "The thickness of the skin," Plastic Recons. Surgery 15,423. SPINRAD, 1). I . (1971). "The role of nuclear power in meeting world energy needs," p. 57 in hvironmental Aspects of Nuclear Power Stations (International Atomic Energy Agency, Vienna). STEINBERG, M. AND MANO'WITZ, B. (1958). An Absorplion Process for Recovery of Fission Product Noble Gases, BNL-493 (T-115) (Brookhaven National Laboratory, Upton, New York). STEPBENSON, M. J., MERRIMAN, J. R. AND DUNTHORN, D. I. (1970). Experimental Investigation of the Removal of Krypton and Xenon from Contaminated Gas Stream by Selectwe Absorption i n Fluorocarbon Solvenls: Phase I Corn pletim Report, USAEC K-1780 (U.S. Atomic Energy Commission, Washington). TADMOR, J. (1973). "Deposition of 86Kr and tritium released from a nuclear fuel reprocessing plant," Health Physics 24,37. TADMOR, J. AND COWSER,K. E. (1967). "Underground disposal of 85Krfrom nuclear fuel reprocessing plants," Nucl. Eng. Design 6, 243. THOMPSON, T. J. (1971). "Role of nuclear power in the United States of America," p. 91 in Environmental Aspects of ATuclear Pmer Staliuns (International Atomic Energy Agency, Vienna). TIPTON,I. H. (1975). Gross and Elemenlal Content of Reference Man, Chap. I1 in Report of ICRP Task Group on Reference Man (Pergamon Press, New York) . TURNER, 0. B. (1970). Workbook of Atmospheric Dispersion Estimaks, Environmental Protection Agency, Office of Air Programs Publication No. AP-26 (U.S. Environmental Protection Agency, Research Triangle Park, North Carolina). Union Carbide Corporation (1967). Cryogenic Data Reference (Linde Division, Union Carbide Corporation, New York City). United Nations (1970). (Population Division) Total Population Estimates for World Regions and Cbuntmks Each Year, 1960-1986, Working Paper No. 34, ESAR/WP34 (United Nations, New York). UNSCEAR (1972). United Nations Scientific Committee on the Effects of Atomic Radiation, Ionizing Radiation: Levels and Eflecls, Vol. 1, p. 72 (United Nations, New York)

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68

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T H E NCRP

SC-1: Basic Radiation Protection Criteria SC-7: Monitoring Methods and Instruments SC-9: Medical X- and Gamma-Ray Protection up to 10 MeV (Structural Shielding Design) SC-11: Incineration of Radioactive Waste SC-18: Standards and Measurements of Radioactivity for Radiological Use SC-22: Radiation Shielding for Particle Accelerators SC-23: Radiation Hazards Resulting from the Release of Radionuclides into the Environment SC-24: Radionuclides and Labeled Organic Compounds Incorporated in Genetic Material SC-25: Radiation Protection in the Use of Small Neutron Generators SC-26: High Energy X-Ray Dosimetry SC-28: Radiation Exposure from Consumer Products SC-30: Physical and Biological Properties of Radionr~clides SC-31: Selccted Occupational Exposure Problems Arising from Internal Emitters SC-32: Administered Radioactivity SC-33: Dose Calculations SC-34: Maximum Permissible Concentrations for Occupational and Non-Occupational Exposures SC-35: Environmental Radiation Measurements SC-36: Tritium Measurement Techniques for Laboratory and Environmental Use SC-37: Procedures for the Management of Contaminated Persons SC-38: Waste Disposal SC-39: Microwaves SC-40: Biological Aspects of Radiation Protection Criteria SC-41: Radiation Resulting from Nuclear Power Generation SC-42: Industrial Applications of X Rays and Sealed Sources SC-43: Natural Background Radiation SC-44: Radiation Associated with Medical Examinations SC-45: Radiation Received by Radiation Employees SC-46: Operational Radiation Safety SC-47: Instrumentation for the Determination of Dose Equivalent SC-48: Apportionment of Radiation Exposure SC-49: Radiation Protection Guidance for Paramedical Personnel SC-50: Surface Contamination SC-51: Radiation Protection in Pediatric Radiology and Nuclear Medicine Applied to Children SC-52: Conceptual Basis of Calculations of Dose Distributions SC-53: Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Radiation SC-54: Bioassay for Assessment of Control of Intake of Radionuclides

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Title Control and Renwval of Radioactive Contamination i n Laboralories (1951) Reunnmendations for W a s k I)isposal of Phosphorus-32 and Iodine-131 for Medical Users (1951) Radiological Monitoring Methods and Instruments (1952) Recammendatirms for the Disposal of Carbon-14 Wastes (19531 Protection Against Betatron-Synchrotron Radialions Up To 100 MiUion Electron Volts (1954) Radioactive Waste Disposal in the Ocean (1954) Maximum Pemissible Bodg Burdens and Maximum Permissible Cbneentrations of Radionuclides in Air and in Water jor Occupational Exposure (1959) [Includes Addendum 1issued in August 19631 Measurement of Neutron Flux and Spectra for PhysS1caland Biological Applications (1960) Measu~ementof Absorbed Dose of Neulrons and of Mixtures of Neutrons and Gamma Rays (1961) Stopping Powers for Use wilh Cavity Chumbers (1961) A Manual of Radioactivity Procedures (1961) safe Handling of Radioactive Materials (1964) Shielding for High-Energy Electron Accelerator Installations (1964)

Radidion Protection i n Educalimal Instilutions (1966) Medicd X-Ray and Gamma-Ray Protection for Energies U p lo 10 McV-Equipment Design and Use (1968) Medical X-Ray and Gamma-Ray Protection for Energies U p 72

NCRP REPORTS

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73

to 10 MeV-Stmdural AhieLding Design and Evaluath (1970) Dental X-Ray Protection (1970) Radiation Protection i n Veterinary Medicine (1970) Precaulions in the Management of Patieds Who Have Received Therapeutic Amounts oj Radwnuclides (I 970) Prolection Against Neutron Radiation (1971) Basic Radiation Protection Criteria (1971) Protection Against Radiation From Brachytherapy Sources (1972) SpeciJication of Gamma-Ray Brachytherapy Saurces (1974) Radiological Paetors Affecting Decision-Making in a Nuclear Attack (1974) Review of the Current State of Radiation Protection Philosophy (1975) Krypton-86 I n the Atmosphere-Accumulation, Biological Significance, and Control Technology ( 1 975)

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Title X-Ray Protection (1931). [Superseded by NCRP Report No. 31 Radium Protection (1934). [Superseded by KCRP Report

No. 41 3 4

X-Ray Protection (1936). [Superseded by NCRP Report No. 61 Radium Protection (1938). [Superseded by NCRP Report No. 131

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NCRP REPORTS

5 6

7

11 13 15 17

18 19 20 21 24

26 29

Safe H a d i n g of Radioactive Luminous Compounds (1941). [Out of print] Medical X-Ray Protection u p lo Two Million Volts (1949). [Superseded by NCRP Report No. 181 Safe Handling of Radioacliw Isotopes (1949). [Superseded by NCRP Report No. 301 Maximum Permissible Amounts of Radioisotopes in the Hunlan Body and Maximum Permissible Concentrations in Air and Water (1953). [Superseded by NCRP Fkport No. 221 Protection Against R a d i a t i m ~from Radium, Cobalt-60 and Cesium-137 (1954). [Superseded by NCRP Report No. 241 Safe Handling of Cadavers Containing Radioactive Isotopes (1953). [Superseded by NCRP Report No. 211 Permissible Dose from External Sources of Ionizing Radialion (1954) i~lcludingMaximum Permissible Exposure to Man, Addendum to National Bureau of Standards Handbook 69 (1958). [Superseded by NCRP Report No. 391 X-Ray Protection (1955). [Superseded by NCRP Report No. 261 Regulation of Radiation Exposure by Legislative Means (1955). [Out of print] Protection Against Neutron Radiation Up fo 30 Million Electron Volts (1957). [Superseded by NCRP Report No. 381 Safe H a d i n g of Bodies Codaining Radioaelive Isotopes (1958). [Superseded by NCRP Report No. 371 Protection Against Radiations jrom Sealed G a m m Sources (1960). [Shperseded by NCRP Reports Nos. 33, 34 and 401 Medical X-Ray Prokclion U p to Three MiUion Volts (1961) [Superseded b y NCRP Reports Nos. 33,34, 35 and 361 Exposure to Radiation in an Emergency (1962). [Superseded by NCRP Report No. 421

The following statements of the NCRP were published outside of the

NCRP Report series: "Blood Counts, Statement of the National Committee on Radiation Protection," Radiology 63,428 (1954) "Statements on Maximum Permissible Dose from Television Receivers and Maximum Permissible Dose to the Skin of the Whole Body," Am. Jr. of Roentgenol., Radium Therapy and Nucl. Med. 84,152 (1960) and Radiology 75,122 (1960) X-Ray Protection Standards for Home Television Receivers, Intenam Stale ment of the National Counnnnlon Rudiation Protection and Measurements (National Council on Radiation Protection and Measurements, Washington, 1968)

NCRP REPORTS

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Spe&$cdion of Units for Natural Uranium and Natural Thorium, (National Council on Radiation Protectiion and Measurements, Washington, 1973)

Copies of the statements published in journals may be consulted in libraries. A limited number of copies of the last two statements listed above are available for distribution by NCRP Publications.

INDEX Absorption a t ambient temperature, 40 Charcoal, 40 Molecular sieves, 40 Adsorption on charcoal, 40,41 Ambient temperatures, 40 Cryogenic temperatures, 41 Atmospheric dispersion calculations for 86H, 19 Eatimate of population dosage for the world, 19 Global scale dilution, 19 Maximum annual average concentration near a fuel processing plant, 21 Maximum concentration, 19 Maximum credible 24-hour concentration near a fuel processing plant, 21 World populstion weighted 8 q r concentrations, 20 Atmospheric krypton, 18 Atmospheric volume, 16 Biological properties of krypton, 4 Anesthetic action, 4 Blood solubility, 4 Diffusion in tissue, 4 Lipid solubility, 4 Radioprotection action, 4 Biological significance of absorbed dose, 36 Carcinogenic effects, 36 Genetic effects, 36 Calculation of dose from 86Kr in the

Clathrate precipitation 2, 45 Concehtrationa of 86Kr measured in northern hemisphere, 33 Cryogenic adsorption, 41 Cryogenic distillation, 44 Deposition of 8bKr on the soil, 17 Dose from bremsstraMung, 25 External bremsstrahlung, 26 Internal bremstraMung, 25 Dose from 85Kr in the airways of the lungs, 31 B~~~marrow, 31 Lung, 31 Ovaries, 31 Testes, 31 from photons produced in a semiinfinite cloud, 22 Dose rate, 22, 29, 30 Dose rate to active bone marrow, 22, 29,30 Dose rate to bone, 22, 29, 30 Dose rate to gonads, 22, 29, 30 Dose rate to lungs, 22,29, 30 Dose rate to skin, 22, 29, 30 Dose rate to soft tissue of the body, 22, 29, 30

Dose rate to subcutaneous tissue, 22, 29,30 Dose rate from beta rays in an infinite cloud, 28 Dosimetry, 22 Environmental dispersal of 8sKr, 16 Absorption by the soil, 18 Adsorption onto particulate matter, 18 Atmosphere, 19 Deposition through adsorption on particulate matter, 17 Dry deposition, 17 Ocean, I6 Waehout of a'%, 17

body, 25 Formulae, 25 Calculation of long-term air concentrations, 60 Carcinogenic effects, 36 Carcinogenic effects on skin, 38, 46 Chemical properties, 1 Chemical reactions, 2 Clathrate formation, 2 Ionic or covalent bonding, 1 Solubility, in nonpolar solvents, 2

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78

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INDEX

Exposure t o the public from stimulation of natural gas, 8 Exposure to 9 Exposure to tritium, 9 Future power requirements, 10 United States energy requirements, 11 World energy requirements, 11 Genetic effects, 36 Hazards in BsKroff-gas removal systems, 41, 44, 45 Interaction of ionizing and ultraviolet radiation, 38,46 Induction of skin cancer, 38 Interim holdup of xenon and krypton, 41 Krypton concentration in air, 16 Krypton in vegetation, 18 86Kr generation and inventory to the year U)o,14 Nuclear reactor mix, 14 World nuclear electric power capacity, 14 86Kr inventory, 10 86Kr releases, 10 86Kr removal from waste gases, 40 Adsorption a t ambient temperatures, 40 Clathrate precipitation 46 Cryogenic adsorption, 41 Cryogenic distillation, 44 Permselective membranes, 45 Selective absorption, 44 Mantle rock capacity for krypton, 18 Mass of K r in atmosphere, 16 Mass of Kr in the mixed layer of oceans, 16 Molecular sieves, 40, 41 Ambient temperature, 40 Cryogenic temperature, 41 Natural sources of 86Kr, 6 Neutron capture reactions, 5 Spontaneous and neutron-induced fissions, 5 Steady-state environmental inventory from natural sources, 5 Nuclear reactor mix, 14 Fast brecder reactor, 14 Light water reactor, 14 Liquid metal fast breeder reactors, 15 Thermal converter reactor, 14

Nuclear weapons testing and production of S 6 K r , 5 Current B6Krinventory, 5 Integrated generation, 5 86Kr generation from U.S. plutonium production, 6 Specific yield of abKr, 5 Underground weapons tests, 6 Off-gas treatment processes for 42 Ostwald coefficient, 25 Peaceful uses of nuclear explosives, 8 Gas well stimulation, 8 Project plowshare, 8 Permselective membranes, 45 Phantom description, 57 Physical properties of krypton, 2 Atomic number, 2 Atomic radius, 2 Atomic weight, 2 Boiling point, 2 Critical point, 2 Demity, 2 Isotopic natural abundance, 2 MeItiog point, 2 Radioactive isotopes, 2 Triple point, 2 Power reactors, 7, 14 Projected carcinogenic effects, 37 Projected genetic effects, 36 Projected 86Kr concentrations, 32, 34 Projected nuclear electric power capacity, 47 Projected skin dose, 46 Projected world population dose commitments, 36 RRd bone marrow, 35 Skeleton, 36 Skin, 35 Properties of Kr and S6Kr, 1 Biological properties, 4 Chemical properties, 1 Physical properties, of krypton, 2 Radiological properties, 3 Radioactive isotopes of krypton, 2 Radiological properties of 86Kr, 3. Decay scheme, 3 Endpoint energies, 3 Fission yields, 4 Half-life, 3

INDEX Radiological properties of a K r (Conlind)

Mean /? energies, 3 Primary radiations, 3 Secondary radiations, 3 Recommended interim policy for reactor releases, 46 Recommended policy for releases from fuel reprocessing plants, 46 Reprocessing plants, 7, 21 Release rate of s6Kr, 7 Maximum annual average 8'Hr concentration, 21 Maximum credible 24-hour 86Kr concentrations, 21

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Selective absorption, 44 Skin dose equivalent rates due to 86Krin the atmosphere, 34 Soil-krypton interaction, 18 Sources, of S6Kr,5 Natural sources, 5 Naval propulsion reactors, 8 Nuclear weapons testing and production of e%-, 5 Peaceful uses of nuclear explosives, 8 Power reactors, 7 Reprocessing plants, 7 Ultraviolet radiation, 38, 46 Washout of S6Kr, 17 Washout coefficient, 17