Report: Safety Considerations in the Operations of the Rocky Flats Plutonium Processing Plant

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SAFETY CONSIDERATIONS I N THE OPERATIONS ROCKY FLATS PLUTONIUM PROCESSING PLANT U. S. Atomic Energy Commission March 1970

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Since the May 11, 1969, fire at the Atomic Energy Commission's Rocky Flats plutonium processing plant,there have been a number of . inquiries and considerable discussion in the news uedi.a regarding public health and safety as an outcome of this fire and of a few other incidents in the plant ' s history since it started fabrication of compocents i n 1953. The purpose of this report is to provide background material, observations, and discussions of various aspects of the health and safety issue as they pertain to the Rocky Flats Rant, and t o the general prob- e lems of plutonium toxicity. The AEC has always followed a very conservative approach with respect to safety. From the outset, AEC installations were designed t o be as safe as possible and workers were trained in safety procedures. The program has been most successful, and the AEC has been frequently cited by the National Safety Council. however, that incidents can and do happen i n any industry where the human element is involved. Strict management and supervisory control can reduce, but never completely eliminate,incidents. Nevertheless, when an incident such as occurred i n May of 1969 i s experienced, the AEC feels an impelling responsibility to review matters of operational safety It is t o be understood, at the affected site and t o sponsor added measures to fortify its position with regard t o public health and safety. going on continuously since the May 11 fire. These activities have been All analyses to date have led the AEC's investigators to the conclu sion that the recent fire,together with the few other industrial

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incidents during past operations, have not resulted in exposure of the general public in t h e surrounding area t o any risk, nor the plant workers t o any hazards of any consequence. conclusion i s one of the purposes of this report. The substantiation of this

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- SUIDIARY OF CONTENTS Section I discusses the choice of Rocky Flats as a site and provides a description of the facility. A summary is presented of wind patterns in the vicinity of the Rocky.Flats Plant. Section I1 describes the filtration systems and air sampling techniques used in Buildings 776-777, with emphasis on their performance during the episode of the May 11, 1969, fire. It describes the air, vegetation, and water sampling programs of the past, together with the soil sampling program recently undertaken. It concludes that the quantity of plutonium released to the environment has been of minute Section I11 explains that the criticality experiments with fissionable matcrials conducted at the Nuclear Safety Facility are, in fact, for the purpose of enhancing safety by realistically determining the allowable configurations of plutonium in storage and in process. These experiments are distinguished from evaluation of hypothetical to determine the larger masses of Section IV lists the It describes the accident situations which are theoretical analyses consequences of unlikely situations involving plutonium than ever considered for actual experiments. management actions taken immediately after the fire. improvements incorporated in the new Building 707 presently under construction which reflect the implementation of added safety features believed prudent as a result of the May 11, 1969, loss.

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--S ect ion V considers several health aspects of piutonium: Part A reports that whereas the concentration of radioactivity in the soil reaching about 7 miles from the plant (approximately 50 square miles i n area) is about one disintegration per minute per square centimeter (dpm/cm ), researchers in this field assert from their studies that levels which are many hundreds of times higher can be accepted as safe.1 Part B briefly treats the ingestion of plutonium, which isa meitns of in take understood t o be less hazardous than inhalation. The level of radioactivity of water in the Great Western Reservoir ncarby is approximately 0.07% of t h e maximum permissible concent ration in water established by the National Council on Radiation Protection and Measurements (NCRP) for the general population. This low-level activity is approximately representative of the activities measured in other nearby reservoirs and water supplies in the vicinity., Part C gives a brief summary of experimental studies in which beagles and rodents were subjected t o inhaled plutonium oxide doses t o observe biological effects. the contention that standards for plutonium oxide inhalation The results of this work support Part D reports on the National Plutonium Registry which maintains records of persons who have been exposed to plutonium and o t h e r radioactive iso:opes heavier than uranium. Its primary purpose

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is to follow case histories of active and terminated employees who have received any exposures of consequence. It is worthy of note that there have been no reports of lung, lymph node, liver, o r bone morbidity attributable to plutonium inhalation. PartE provides the information on membership and functions of the three expert groups concerned with the establishment of radiation Protection(ICRP),the National Council on Radiation Protection the International Commission on Radiological --S ect ion VI is a list of Suggested References.

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The question of the migration of 239pU0 lymph nodes resulting in higher tissue concentrations with longer. residence times has also been raised. Experimental evidence has established that for relatively insoluble forms the major accumulation of plutonium which occurs outside the lung isin t h e tracheobronchial lymph nodes. For nearly a decade following the exposure of beagles to insoluble 239pU0 a continuous excretion of 239Pu from the body was observed along with the accumulation in the pulmonary lymph nodes. As a result the average concentration of plutonium in these lymph nodes was greater than that of the lung tissue. equally susceptible to radiation-induced cancer, then one would However, i f both tissues were expect to observe neo plastic changes inthe lymph nodes before they occurrcd inthe lung; this has not been the case. The general problems of nonuniform distribution of dose which can occur froin deposition of 239h0 the relative Concentration i n lymphoid tissue were considered particles in the lung and by the International Commission on Radiological Protection in 19G6 and i n 1969 and are presently being studied by atask group of t h e ICRP. D. 7Eiomedical Programs t o Study Potential Effects of Plutonium i n Man The National Plutonium Registry was formally established in 1968

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Manford Environmental Health Foundation, a contractor to the Atomic Energy Commission, Richland, Washington. Battelle-Northwest, a d5vision of the Bat tell e Memorial Institute, and alsoa Hanford contractor,assists w l th the administration of the project. An advisory cornnittee representing the most authoritative radiation protection opiikon available assists in establishing long-range policies of the Registry. Nembers of the committee are: associated with the atomic energy program i n the Hanford area, is Director of the Registry. The. purpose of t h e National Plutonium Registry is to maintain records i n one plzce of persons who have been exposed t o plutonium, o r other radioactive elements heavier than uranium, during the. course of their employment, in st cn ces of biological effects attributable to the deposition of plutoniuin i n man, the AEC has expressed interest in the possib le effects for many years. The lack of biological effects is primarily because of effective control programs during the Although there have been no reported 25 years i n which relatively large amounts of plutonium have been handled a t Hanford and at other nuclear installations. However, pathological changes have been observed i n animals used in research progrnms t o determine the biological effects of plutonium. I n

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The National Plutonium Registry will be a national focal point for gathering the latest and most precise information about the possible effects of plutonium and other transuranic elements on man. The National Plutonium Registry will ensure correlation of the details of exposure to the radioactive materials with the long-term health record of the workers. Major national and international journals,interested in radiation health problems, have been given infomation regarding the in it in tion of the National Piutonium Registry. Other countries, having potential plutonium exposure problems, will be encouraged t o develop prirallel efforts and pool information i n order t o broadcii the statistical base. A description of the National Plutoniuin Registry was presented to the attendees of an inter - national conference entitled "Diagnosis and Treatment of Internally Deposited Radionuclides" held at Richland, Washington, Classification of both active and terminated plutonium workers based upon the type and extent of deposition or exposure t o 239pU02 orthe equivalent amounts of other transuranic -elements i n terms of yz miss i ble exposure limits have been established. One group fncludes depositions, based on urine analysis, estimated t o be of the order of one-half the permissible body burden o r

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positive urine samples ayear or more after thc latest deposition or an indication of positive pulmonary retention as determined It will also include inhalation cases which still have by o t h e r hcal.th physics procedures such as whole body counting. This group will also include all localized residual cuta neo is and subcutaneous depositions at any amounts except for depositions a t less than 5 niillimeters depth established at less than Another group includes depositions, based upon bioassay procedures, between 0.004 microcurie and 0.02 microcurie. A third group includes all workers occupationally exposed t o potential depositions of plutonium who are systematically examined for the detection of ' such deposition not included above. It is also planned t o study those transferred or retired employees still living in the same local area i n which the facility is located. Those living some distance from the local facility will be followed by the Registry through a family physician, i f possible, o r by sone other means. That National Plutonium Registry also will obtain autopsies from deceased plutoniun workers. It is not anticipated that it will be possible to obtain the whole body for scientific study i n most organs including lymph nodes for gross and his to logical study. Ifowever, the usual autopsy samples will be taken from

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Care vi11 be takcn i n measuring the radioactive content of organs, including lymphoid tissue, and i n comparing the resultant values with the most recent estimates of organ burden obtained prior to death on the basis of urinary excretion, metabolic models, or whole body counting. Organ depositions, determined by autopsy, will be correlated with the uptake, elimination, and deposition i n enimals to deter nine the validity of extrapolations to man. Before epideniiological observations regarding any association I of bio logic d effects of previous exposure t o plutonium are established,the entire life history of the individual will be considered, including all other environment'al toxic and carci - n0genj.c factors of occupational exposure, prior to and subsequent to any plutonium exposure. For example, lifetime cigarette consumption and medical exposure to radiation will be considered i n such a personal history. The National Plutonium Registry started to interview employees a t the Ilanford complex in July 1969. 300 crnployecs had been interviewed by physicians. By early December, over only 2 chose not t o cooperate with the project by signing a release for medical and health physics information. It is expected that about 2,000 employees will be contacted as part of the Ilanford szniple. By early December 1969, 70 employees had returned signed autopsy releases. All autopsy releases will

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I n January 1970, the National Plutonium Registry received first autopsy seriiples from a n emp1.oyec 'who died from a heart attack. The samples are now inthe process of being analyzed. A number of plutonium workers have accumulated small b u t measureable amounts of plutonium since the beginning of the nuclear energy progrcm. The most comnion sources of internal contamination have been puncture wounds and inhalation. on the health of workers exposed t o plutonium in mounts in excess of the maximum permissible level and have provided estimates of radiation dose and time since exposure. reports of lung, lymph node, liver, o r bone morbidity attributable Several authors have reported There have been no A dozen or so of these cases represent exposures of 24 and 25 years ' duration and are of special interest. This group i s kept tinder surveillance and is subjected t o periodic thorough medical examinations. No members of this group have experienced m y change i n physical condition that cannot be conside red as part of natural change due t o aging. 15 subjects represent exposures of 6to 17 years' duration. Although the number of cases i s small, the human data is extremely Another group of valuable in assessing risk evaluations. It io also important to point out that measurements are made continuously on the mounts of 23gh02 contained inthe lungs and

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other tissues of human subjects not exposed occupationally. A t one installation alone, the autopsy samples obtained from more than 300 subjects have been analyzed over the years for plutonium, About half of the samples represent: subjects from the local area whereas the other half represent subjects from the northeastern United States. Measurements of plutonium inthe human lung and othzr tissues are also made and reported by the U. S. Public Health Service. Additionally, similar measurements have been reported from other countries including the United Kingdom, Canada, and the USSR. Another epidemiological study,in which the health and mortality rate of employees of AEC contractors at Hanford and Oak Ridge are coinpared with well-defined control populations t o de terniine if there are any detectable effects resulting from low-level occupational exposure to ionizing radiation, including plutonium, D r . Tinomas F. Mancuso, School of Public Health, University of facilities from 1944 forward is being reconstructed from existing records. Death certificates are obtained from state agencies t o determine tine and cause of death of each individual. Disability information i s obtained from the Social Security Administration and other records. This program i s under the direction of Exposure history of employees working at these It is expected that this study will be