Source Book on Plutonium and Its Decontamination

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f SOURCE BOOK ON PLUTONIUM AND ITS Defense Nuclear Agency DEFENSE NUCLEAR AGENCY

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SOURCE BOOK ON PLUTONIUM AND ITS 8. PERFORYING ORG. REPORT NUMBER 8. CONTRACT OR GRANT NUMBEN(.) 9. PER FOR Y ll lG ORGANIZATION MAYE AND ADOUESS Defense Nuclear Agency I I lo. PROGRAM ELEMENT. PROJECT. TASK AREA k WORU UNIT NUMBERS Kirtland AFB, New Mexico 87115 11. CONTROLLING OFFICE NAME AN0 AODRESS I 12. REPORT DATE Headquarters, Defense Nuclear Agency 15. SECURITY CLASS. (01 lhl. npon) The effort expended by the study group in this undertaking was designed to accunulate as much information as possible that might provide a basis Cor a source book on ilutonium, its deposition and retention in the human body. and methods to reduce the ilutonium contamination hazard. The effort was divided between: iearch of past and current documents, manuals, regulations, etc., personal contact vith knowledgeable persons in the field and by attendance a t meetings and symposia hat were fortuitously scheduled during the early months of the study, and ( 2 ) UNCLASSIFIEDDD , , A ~ 1473 EOITIOU o r 1 NOVII IS OIISOLLTL

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development of the coupled differential equations, based on the 1965 and the proposed 1973 physiological lung models, that predict the deposition and translocation of inhaled plutonium in the human body. A historical review of plutonium and the general contamination situation, along with a review of early IJ.S. policy ( e . g . , in the days of the Manhattan P.roject), provide a good background for this problem. Next, the biology of plutonium contammation is discussed; past a s well as current research in this field conducted by the DOD. AEC. and other agencies is reviewcd. New concepts and ideas. such a s lung lavage and the use of chelating agents, are introduced which are currently being used to reduce plutonium body burdens. That plutonium which remains in thc body after inhalation (the most likely, a s well as most dangerous, ing-ess method into the body) is translocated from the lung lo the lymphatic system, blood. bone. l i \ ~ v r , and gastrointestinal tract; the differential equations describing these phenomena a r c solved and with the hcst values available for the constants, graphs and tables a r e presented that give thc burdens, doses, and dose rates to these d i f f e r e d parts of the body. A very important conclusion reached, based on the 1965 physiological lung model and shown even more emphatically by the proposed 1973 lung model, is that the lung is the critical organ and not the lymph nodes o r lymphatic system as lately proposed by a number of people. a s they appear in the literalure available in this country, a r e given to give the reader an overall view. to the decontamination operation and includes decontamination methods and their can refer; 1 0 1 references a r e cited, and some of these references refer to hundreds of Foreign standards for plutonium contamination levels. The last section of the report gives much useful information relating The entire report is very rich in citing references to which the reader

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TABLE OF CONTENTS I THE PLUTONIUM HAZARD ................ The General Contamination Situation ............. The Early Years ........ The Manhattan Project ...... To the Present ......... Atomic Energy Commission Policy Policies of Other Federal Agencies PHYSICAL PARAMETERS OF PLUTONIUM CONTAMINATION Physical Properties of Plutonium ............... Dispersion of Hazardous Material .............. Resuspension of the Hazard ................ The Early Years .................... Recent and Current Research ................ Particulate Implants. Intubation and Injection ......... Diagnosis and Treatment ................ Reduction of the Body Burden ..............

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TABLE OF CONTENTS (Continued) V THE DEPOSITION AXD RETENTION OF INHALED PLUTONIUM IN THE Methods of Decontamination

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LIST OF TABLES Early Radiation Dose Limits ................ Plutonium Occupational Protection Criteria Dmived During the Manhartan Plutonium Standards Adopted During the 1950's .......... 10 CFR 20 Radiation Exposure and Plutonium Limits ........ 1959 Recommendations of the NCRP for Plutonium ......... Percent of Time a 15 Rem Committment is Exceeded During Plume Passage at Distance Shown ................... Summary of Deposition Calculatians ............. Summary of Federal Agency Plutonium Decontamination Standards . . . Tumor Probability f3om Lung Exposure to 16 nCi of 2 3 ~ u 0 Judgment and NCRP Values (1965 Lung Model) Constants for use with the 1965 Lung Clearance Model for 2 h ' u 9 . . . Lifetime Organ Doses for an Area Contaminated with 239F'u02. Plus Organ Dose Rates Obtained from an k e a Contaminated with 239~110~of Effect on the Body Organs for Different Air Clearance Rates (1965 Lung Variability of Soil Sampling Data .............. Criteria for Scheddiig Feces Samples ............ Types of Data which may be Collected for Plutonium Inhalation Incidents . Percent Efficiencies for Various Hard Surface Decontamination Methods . Constants f o r use with the Proposed 1973 Lung Clearance Model for Organ Dose Rates for an Area Contaminated with 239Pu02 of So = 5% g/m2. Effect on the Body Organs for Different Air Clearance Rates (1973 Lung Some Foreign Plutonium Decontamination Standards ........

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LIST OF FIGURES Summary of Laboratory Resuspension Tests Initial Plutonium Deposit and Burden at Death for Dogs ........ Theoretical Plutonium Urinary Excretion Curves. Total Deposition of Inhaled Particles .............. Schematic of Physiological Lung Model for Dust Deposition Sites and Lung Burden following Inhalation of 23%0 Dust versus Time of Exposure in a Contaminated Area of So = 50 IJg/m2 &ame graph for both the 1965 and proposed 1973 lung models) ............... Relative A L r Concentration as a Function of Air Clearance Time Lung Dose following Inhalation of 23%02Dust versus Time of Exposure in a Contaminated Area of So = 50 Pg/m2 (Same graph for both the 1965 and proposed 1973 lung models) ................. Cymphatic System Burden following Inhalation of 2 3 9 ~ ~ 0 ~Dust versus Time Lymphatic System Dose following Inhalation of 2 h u 0 2 Dust versus Time of Exposure in a Contaminated Area of So =50 Pg/m2 (1965 lung model) . . Blood Burden following Inhalation of Z3%uO2 Dust versus Time of Exposure in a Contaminated Area of So = 50 P m2 (1965 lung model) ...... Liver Dose following Inhalation of Contaminated Area of So = 50 Pg/m2 (1965 lung model) Dust versus Time of Exposure Bone Dose following Inhalation of 23$u02 Dust versus Time of Exposure in a Lymphatic System Burden following Inhalation of 2 3 9 ~ ~ 0 ~Dust versus Time of Exposure in a contaminated Area of So =50 Pg/m2 (proposed 1973 lung Lymphatic System Dose following Inhalation of 2 3 9 ~ ~ 0 2Dust versus Time of Exposure in a Contaminated Area of S o = 50 Pg/m2 (proposed 1973 lung Blood Burden following Inhalation of 239Pu02 Dust versus Time of ExTosure in a Contaminated Area of So = 50 Pg/m 22 (proposed 1973 lung model) in a Contaminated Area of S o = 50 P$/m2 (proposed 1973 lung model) Bone Dose following Inhalation of 23 PUO Dust versus Time of Exposure

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The effort expended by the study group in this undertaking was designed to accumulate as much information as possible that might provide a basis for a sourcebook on plutonium and its decontamination The effort was divided between a literature search of past and current documents. manuals, regulations, e t c , personal contact wlth knowledgeable persons in the field and by attendance at meetings and symposia that were fortuitously scheduled during the early months of the study. effort would have been more difficult but for the many persons who have helped the study group along the way. Doors were opened and comments and information were freely given at every stage of the effort. Although it would be impossible here to thank each contributor by name, we do want to take this opportunity to achowledge, in this general way, the aid that was extended to us. This study is divided into seven major sections. The contents of the sections are: Section I presents a general statement of the plutonium hazard. It is included so that the reader can place himself on common ground with the information which follows in subsequent sections of the Section I1 covers published policy o r directives of the DOD, Atomic Energy Commission (AEC) and federal agencies relating to radiation decontamination, exposure limits and contamination limits. Section Ill deals with DOD, AEC o r other research that has contributed or may contribute to an understanding of the physical portion of the hazard model, that is, what happens from the initial accident until the plutonium aerosol i s inhaled. Section IV is a review of the research accomplished and planned to develop information concerning the biological hazard, that is, what happens to plutonium once it is in the body. Section V presents the current 1965 lung model and develops the calculations which describe deposition and retention of respirated plutonium in the human M y . Section VI lists foreign standards for plutonium contamination levels as they appear in literature available in this country. Section VI1 compiles information relating to the decontamination operation and includes some decontamination methods and expectations. Appendix A uses the proposed 1973 lung model to update the work in Section V. References cited herein are current a s of December 1972.

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THE PLUTONIUM HAZARD This study has been designed as a primer for those personnel having responsibilities for plutonium bearing weapons o r the decontamination Of areas affected by weapons accident plutonium contamination It has been prepared with the hope that a general background knowledge of plutonium and its hazards will result in better DOD operations and an enlightened personnel force. THE GENE.RAL CONTAMINATION SITUATION Experience indicates that plutonium contamination will result when a nuclear weapon is involved i~ a fire o r impact situation sufficient to violate the weapon’s containment. The plutonium may bum o r the impact may cause detonation of the high e.xplosive content of the weapon. In each case, plutonium, generally in the form of oxides, will be dispersed. The extent and character of the dispersed material is a function of many variables. Among these are the heat and duration of the fire, the containment material involved, the amount of high explosives and plutonium, aerodynamic variables of wind and stability and many more. The plutonium, once on the ground o r other surfaces, should not he considered as fixed in place. It i s subject to resuspension into the a i r , adhesion to ground o r airborne material, and settling deeper into the soil or other porous surfaces. The primary plutonium hazard is considered to result k o m inhalation of the aerosol. (Aerosol is the generally accepted term for airborne particulate plutonium). The aerosol is present in the initial dispersal cloud and in material resuspended by natural o r human activity in the area. Some of the aerosol is retained in the lung where it causes a radiological insult due to its alpha activity and long lung retention time. Transport to other body organs by body processes is of concern because of significant retention times at these other locations. Modes of entry into the body other than inhalation are considered to be less hazardous. These include absorption through the intact skin, deposition in open wounds and ingestion via foods grown o r produced on contaminated ground. Experience from various tests, previous accidents and theoretical calculations indicate that although a significant body burden of plutonium may be received during passage of the initial cloud, the greater danger to population appears to arise k o m long term’occupancy of a contaminated area wherein the population is subjected to the resuspended radionuclide (Ref. 1). If the affxted area is to be utilized after the accident, some decontamination effort must be undeaaken

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REVIEW OF U.S. POLICY AND DIRECTION CONCERNING The development of current policy and direction concerning plutonium contamination had its genesis in the discovery of X-rays (1895) and radium (1898). their subsequent use and the inevitable incidents of biological damage which followed. The fIrst organized efforts to establish protective criteria for these new tools were made 30 years later. In 1928 the Second International Congress of Radiology established the Committee on X-ray and Radium Protection. The U. S. Advisory Committee on X-rays and Radium Protection was organized in 1928 to provide U. s. input to the International Committee. These committees were the forexunners of the current International Commission on Radiation Protection (ICRE') and the U. S. National Council on Radiation Protection and Measurements (NCRP). Table I lists the early recommendations of these organizations for the employment of these EARLY RADIATION DOSE LIMITS It is of interest to note that these last recommendations are equivalent to 36.5 rem per year, more than seven times the currently permissible annual exposure dose for radiation workers. In the early 1920's the harbinger for present plutonium standards emerged from a factory in New jersey in the form of the deaths of a number of women employed as luminous watch face painters. Subsequent investigations over the period of several years pointed to the radium in the paint mix as the culprit (Ref. 3). By this time radium was also being employed in solutions as a tonic (Ref. 4). During the 1930s the work of Evans and his associates (Refs. 5,6), in following radium cases and determining the biological parameters of uptake, elimination and body-burdens, resulted in the recommendation that 0. l p g of radium constitute a tolerance quantity and that 10- C i / l of radon gas used as an air concentration limit (Ref. 7). Thus, in 1943 when the Manhattan District Plutonium Roject was beginning there were only three tolerance values for occupational exposure to radiation and radioactive materials (Ref. 2). 2. 0.1 pg of radium as a maximum body burden. 3. 10 C i / l of radon as an occupational ai? concenmation.

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THE MANHATTAN PROJECT The extraordinary safety record of our atomic indushty is typified by events within the Manhattan District in early 1944. At a time when plutonium was available in only milligramamounts (much less for biological study), it was suggested by Dr. Hamilton at Crocker Radiation Laboratoryin Berkeley, California, that plutonium might be less toxic than radium by a factor of 50 and that 5u g(0. & Ci) be used a s an internal tolerance level. The estimate was probahlybased on equivalent alpha energydepositionincornparisonwithRa-226(Ref. 2 Based onthis burdenatwo-year occupationalair concentrationof remained as the air concentrationguide for the remainder of the Plutonium Project. It is interestingtonote that this valuecorresponds to a lungburdenofo. 04, Ci, avalue that is currentlyaccepted as thenon-occupaintroduced to the MPBBbecause studies at Berkeley concluded that plutonium inhone was much less uniform than was radium. Hanford Operations authorities introduced a factor of 10 for their operations. In August 1945 Hanford established dr in hp water standards based ona maximum permissible body burdenof 0.5.1 g air tolerance of 5 x 10-10pg/cm3 (3 x 10-! 'p Cl/m3) was suggested based on the 0. 1 R/day limit for Table II summarizes the …