U.S. Department of Energy, Office of the Press Secretary, Washington, DC 20585
The Department of Energy has declassified the amounts of gaseous tritium released to the atmosphere from specific tritium purification and loading buildings at the Savannah River Site, near Aiken, South Carolina.
U.S. Department of Energy
Office of Public Affairs
Contact: Sam Grizzle
U.S. Department of Energy, Office of the Press Secretary, Washington, DC 20585
Q. Are releases of radiation and radioactive materials, such as tritium and uranium from operations at the Savannah River Site, a health hazard to the workers or the public?
A. The Department of Energy is addressing the question of health hazards from exposures to materials, such as tritium and uranium, by sponsoring a comprehensive package of health studies of Savannah River Site workers and community residents. They include the following:
A program for surveillance of illness among Savannah River Site workers that systematically collects and analyzes data on worker absences began in 1992. This program will help identify patterns of illness and injury so that specific workplace exposures can be better monitored and controlled.
The medical surveillance program of Savannah River Site examines workers who have been identified by their unique exposures or occupations. Medical surveillance activities are being expanded at all Department of Energy sites. The program will be tailored to specific site needs such as the identification of early signs of organ damage from heavy metals such as uranium.
A Department of Energy mortality study of 9,860 white males was published in 1988. These men were employed for 30 days or more before 1975 and were followed through 1980. The study did not contain information on exposure to ionizing radiation. Eleven of the 43 categories of cause of death among hourly workers had statistically significant fewer deaths than expected. There were thirteen of the 43 categories among salaried workers with fewer than the expected number of deaths. The only statistically significant excess mortality rate was for leukemia among hourly workers first hired before 1955 and employed between 5-15 years. Information on ionizing radiation is now available and is the basis of a second study that will be completed in 1994. The preliminary findings from this second study are being reviewed by the National Institute for Occupational Safety and Health who currently manage Department of Energy analytic epidemiology studies.
During calendar year 1993, approximately 1000 workers and visitors were monitored at the Savannah River Site as part of the internal dosimetry program. About 500 workers have positive tritium (tritium) doses above the minimum detectable dose of 1 mrem committed effective dose equivalent (50-year committed effective dose equivalent.) The range of these positives was from 1 mrem to 30 mrem committed effective dose equivalent. The collective dose was 5-6 rem committed effective dose equivalent. For tritium the annual effective dose equivalent is the same as committed effective dose equivalent. Six of these workers received plutonium doses above the minimum detectable dose of 10 mrem committed effective dose equivalent. Two of these positives ranged from 10-100 mrem and the other four fell between 100-208 mrem committed effective dose equivalent. The highest dose in recent years is one individual who received an uptake of plutonium in 1991 of 15.0 rem committed effective dose equivalent. This is quite unusual for the site but the potential does exist there due to the old design of some of the facilities. Potential for uranium exposures are practically nil at Savannah River Site.
Since startup of the first reactor at Savannah River Site in December 1953, internal dose has been followed. The total collective dose from plutonium exposures for the some 70,000 people monitored over these years at Savannah River Site is approximately 70,000 rem collective committed effective dose equivalent, an average of about 1 rem collective committed effective dose equivalent dose per each worker. Total dose to Savannah River Site workers has dropped significantly in recent years. The total collective dose in 1993 was 261 mrem committed effective dose equivalent, as compared to collective doses of 1000-1200 mrem committed effective dose equivalent in the production years of a decade ago.
In previous years of the Savannah River Site production activity, tritium doses averaged about 5 percent of the total Savannah River Site worker dose. In recent years, tritium dose has dropped to 2-3 percent of the total Savannah River Site worker dose. No Savannah River Site worker has received a tritium dose in excess of 100 mrem in the past several years.
Doses from intakes of actinides at Savannah River Site have averaged about 6.5 percent of the total occupational radiation dose received by Savannah River Site workers since site operations began. Most of the highest individual doses to Savannah River Site workers, however, are due to intakes of actinides.
The first phase of a dose reconstruction study is being performed by the Centers for Disease Control and Prevention at the Savannah River Site, and it will be completed this year. This is a document review to help describe the historical operations of the site and identify the materials released to the environment.
In another program, the Medical University of South Carolina, under a State Health Agreement, has established a cancer surveillance system in the region of the Site. The recording of cancer cases in this system can be used to detect unusual patterns or clusters of cancer near the site.
Q. Have you previously announced tritium releases to the public?
A. Yes, data were announced annually to the public on total releases from combining several buildings in F and H areas. The more specific data released today provide further detail on tritium released.
Q. Why was tritium released; it is costly, radioactive, and dangerous?
A. Tritium or any form of hydrogen is difficult to completely contain in a large system. The new replacement tritium facility will incorporate the newest technology and be much improved over our earlier buildings.
Q. Can nuclear weapons be made without tritium?
A. Yes, but they would make significantly less efficient use of our special nuclear material. The U.S. stockpile of nuclear weapons would have to be redesigned to eliminate the tritium.
Q. Why was the data classified for 40 years?
A. Tritium release information was classified in the past because it was felt it could be correlated to estimates of tritium and related production. However, recent analysis showed that there is currently little or no correlation with production so tritium release information can be declassified.
Q. In 1958, there was a significant release of tritium at Savannah River. What caused it? What were the hazards?
A. The atmospheric releases of tritium were the largest for 1958 of any single year of operations (2.36 million curies). Accidental releases and high production activity at the Savannah River Site is believed to be the primary reason for the magnitude of annual releases during this time period when all five reactors and all other production facilities were fully operational. The 8-year period from 1957 through 1964 was the period of highest atmospheric releases of tritium during the history of the site. No Savannah River Site worker exceeded current Federal guides for radiation dose during 1958. The maximum offsite dose to an individual in 1958 was 1.87 mrem, compared to the current Federal guide of 10 rem due to atmospheric releases. A detailed discussion of tritium at the Savannah River Site can be found in "Assessment of Tritium in the Savannah River Site Environment (U)," WSRC-TR-93-214 (October 1993).