Annual NNSS impact report released

About 120 people were concerned enough about the shipments of uranium to the Nevada National Security Site. They showed up at a public hearing Nov. 14 at Nevada Treasure RV Resort on the far north end of Pahrump.

But the 2012 annual environmental monitoring report states hundreds of thousands of cubic feet of low and mixed low-level radioactive waste was disposed of at area five on the NNSS without controversy.

The NNSS, formerly known as the Nevada Test Site, measuring 1,360 square miles, has been the nation’s primary location for ensuring the nation’s stockpile of nuclear weapons remains safe and reliable. Other missions include weapons of mass destruction first responder training; controlled release of hazardous material at the Nonproliferation Test and Evaluation Complex; as well as remediating contaminated sites including disposal of low and mixed low-level radioactive waste and environmental research.

Tests conducted in the 1950s were in the air. Beginning in late 1962 until 1992, nearly all of the 828 underground nuclear tests were conducted in sealed vertical shafts drilled into Yucca Flat and Pahute Mesa or horizontal tunnels in Rainier Mesa.

The 2012 annual NNSS environmental monitoring report states the maximum dose to the public from inhalation, ingestion and direct exposure pathways attributable to NNSS operations is .54 millirems per year, well below the dose limit of 100 millirems per year established by the U.S. Department of Energy for radiation exposure to the public. The NNSA said the average person in the U.S. receives about 310 millirem per year from natural sources and an additional 310 millirem from medical procedures and consumer products. The Nuclear Regulatory Commission set the dose limit for radiation workers at 5,000 millirem per year.

“This total dose estimate is indistinguishable from natural background radiation experienced by the public residing in communities near the NNSS,” the annual report states.

By comparison, the National Nuclear Security Administration said the dose from cosmic and terrestrial radiation at Indian Springs is 100 millirems per year, the dose from natural radionuclides in the body is 31 millirems and the dose from inhalation of decay products from natural radon is 229 millirems per year.

“For people living in areas around the NNSS, less than 2 percent of their total radiation exposure is attributable to past nuclear testing or to current NNSS activities,” the report states.

The NNSA said 806,544 cubic feet of waste was disposed of at the Nevada National Security Site in 2012 in low-level waste and mixed low-level waste disposal cells at area five. The NNSA reported waste volumes were within permit limits and groundwater monitoring verified the disposed waste wasn’t migrating to the groundwater or threatening the environment.

The NNSA reported 1,355 tons of mixed low-level waste were disposed of on site, .28 tons of polychlorinated biphenyl (PCB) waste was shipped to an off-site disposal facility and .39 tons of waste explosive ordinance were detonated on site, all in accordance with state permits.

From the 1960s, when waste disposal began at the NNSS, through Dec. 31, nearly 1.6 million cubic yards of waste have been disposed of with an estimated cumulated radioactivity of 15.5 million curies.

“On site air sampling stations detected man-made radionuclides at levels comparable to previous years and well below the regulatory dose limit for air emissions to the public of 10 millirem per year. The estimated dose from all 2012 NNSS air emissions to the maximally exposed individual is .17 mrem/year,” the NNSA report states.

An estimated 21.62 tons of air pollutants were released on the NNSS in 2012, the majority were from diesel generators.

For the Emergency Planning and Community Right to Know Act the NNSA reported 170,486 pounds of lead and 268 pounds of mercury were released in 2012, the majority was from on site disposal of cleanup and building demolition materials from other DOE facilities or from waste generated on site.

When it came to the Endangered Species Act, the NNSA reported 15.21 acres of tortoise habitat were disturbed in 2012, no tortoises were harmed or displaced, one was found injured on a road and seven were moved off roads to safety. The NNSA entered into an agreement with the San Diego Zoo and U.S. Fish and Wildlife Service to purchase radio telemetry equipment to monitor movements of 11 adult tortoises, their habitat is mainly in the southern one-third of the NNSS. The San Diego Zoo also released 60 radio-marked juvenile desert tortoises in September 2012. Researchers captured four mountain lions who were outfitted with radio collars.

Four accidental bird deaths were documented. The NNSS has 27 mammals, over 250 birds, two reptiles, a mollusk and 18 sensitive plants.

Concentrations of contaminants in the three permitted public water systems on the NNSS were below state and federal permit limits, the NNSA reported.

But the annual report states, “approximately one-third of the 828 underground nuclear tests on the NNSS were detonated near or below the water table, resulting in radioactive contamination of groundwater in some areas. In addition, the 100 atmospheric nuclear tests conducted on the NNSS and numerous nuclear-related experiments results in radioactive contamination of surface soils, materials, equipment and structures, mainly on the NNSS.”

The NNSA estimates the total amount of radiation below the groundwater table since the last underground test in 1992 is approximately 40 to 60 million curies, a curie is a measure of radioactivity based on the observed decay rate of one gram of radium. Those contaminated areas are called Underground Test Area corrective action units, which are under a federal facility agreement and consent order between the State of Nevada, DOE and Department of Defense. About 3,000 corrective action sites have been identified, the NNSA said many have already been remediated or closed.

A test well at Pahute Mesa was found to have 13,180 picocuries per liter of tritium when it was sampled in October 2009, about 2,350 feet west of the NNSS boundary and two miles from the nearest underground nuclear tests in 1968 and 1975, the first off-site well in which radionuclides from underground nuclear testing activities at the NNSS have been detected.

The NNSA said the finding wasn’t unexpected because the groundwater flow and transport model for the area, published in 2009, predicted tritium contamination above the Safe Drinking Water Act limit of 20,000 picocuries per liter should be present off the NNSS by 2015. Further sampling of 10 wells downgradient from Pahute Mesa didn’t detect the presence of man-made radionuclides, except for a marginally measurable amount of 4.2 picocuries per liter of tritium at one well in March 2012, the NNSA reported.

Three on-site monitoring wells had detectable concentrations of tritium ranging from 94 to 355 picocuries per liter, all well below the 20,000 picocuries per liter drinking water limit, all were within .6 miles of an historical underground test.

Total man-made radionuclides emitted into the air from all sources on the NNSS in 2012 was estimated to be 228 curies. They included contaminated soils at the Schooner and Sedan craters, the two waste disposal sites and historical test locations. A monitoring station in Pahrump detected an off site exposure of 72 milliroentgens per year, the lowest among the locations.