Public Health and Environmental Radiation Protection Standards for Yucca Mountain, Nevada (40 CFR Part 197)
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Yucca Mountain, Nevada is the Department of Energy’s (DOE) potential geologic repository designed to dispose of spent nuclear fuelspent nuclear fuelFuel that has been withdrawn from a nuclear reactor after use. It is still highly radioactive. and high-level radioactive wastehigh-level radioactive wasteHighly radioactive materials produced as a byproduct inside nuclear reactors. Other highly radioactive materials can be designated as high-level waste, if they require permanent isolation.. The EPA's role at the proposed Yucca Mountain repository was to set standards to protect public health by limiting the radiation exposure to individuals in the vicinity of the facility potentially exposed to releases of radioactive material. The EPA’s standards address all environmental pathways, including air, groundwater and soil. The standards:
- Set a dose limit of 150 microsieverts (15 millirem (mrem))milliremThe millirem is the U.S. unit used to measure effective dose. One millirem equals 0.001 rem. The international unit is milliSievert (mSv). per year for members of the public in the general environment around Yucca Mountain from the management and storage of radioactive material on the site, both inside and outside the repository.
- Set a dose limit to the reasonably maximally exposed individual of 150 microsieverts (15 mrem) per year for the first 10,000 years after disposal. From 10,000 years to 1 million years after disposal, the dose limit becomes 1 millisievert (100 mrem) per year.
- Take into account exposure through all potential pathways, and account for releases caused by a borehole going through a waste container and into the underlying groundwater (the “human intrusion” standard).
- Require DOE to assess the effects of climate change, earthquakes, volcanoes, and corrosion of the waste packages on the performance of the repository system during the 1 million-year period.
- Set the following limits on radionuclides in groundwater for 10,000 years of undisturbed performance of the repository:
|Radionuclide or type of radiation emitted||Limit||Is natural background included?|
|Combined radium-226 and radium-228||5 picocuries (0.185 becquerel (Bq)) per liter||Yes|
|Gross alpha activity (including radium-226, but excluding radon and uranium)||15 picocuries (0.555 Bq) per liter||Yes|
|Combined beta and photon emitting radionuclides||40 microsieverts (0.04 millisievert or 4 mrem) per year to the whole body or an organ, based on drinking 2 liters of water per day from the representative volume||No|
The U.S. Nuclear Regulatory Commission would incorporate these standards into the licensing regulations for Yucca Mountain.
The standards currently in place were issued in 2008 and are a result of a revision to the original 2001 standards. The 2001 disposal standards included a 10,000-year compliance period for protection of individuals and groundwater resources from potential release of radionuclides from Yucca Mountain. The EPA required dose projections beyond the 10,000-year compliance period, but did not establish a specific compliance standard for the longer-term projections.
In July 2004, the U.S. Court of Appeals for the District of Columbia Circuit ruled that the 10,000-year time period was inconsistent with recommendations made by the National Academy of Sciences (NAS) in a 1995 report. The NAS had recommended that the EPA set a standard to limit exposure to individuals at the time of peak risk. The Court did not rule that EPA’s standards were not protective. It ruled that the EPA standards were invalid to the extent that they did not extend to the time period recommended by the NAS. Download the NAS report.
The 2008 standards maintains all the protections from the 2001 rule, and add a 100 millirem (1 mSv) per year dose limit beyond 10,000 years up to 1 million years.
Download the NAS report, Technical Bases for Yucca Mountain Standards (1995).