Tritium leaks at nuclear power plants

StoryImage( ‘/Images/Story//Auto-img-114064137528148.jpg’, ‘Photo by Sonia Vogl’, ‘Cooling Water Inlet and outlet: Byron nuclear power plant owner Exelon reported that water in the Byron vaults was tested and found to contain tritium concentrations of 86,000 picocuries per liter. Tests are being run to determine if the tritium has leaked into ground water on the plant site. According to Exelon, the Byron tritium concentrations pose no health or safety threat to employees or the public.’);

A plume of radioactive tritium was detected in the groundwater outside the Braidwood nuclear power plant in Will County. The plant design is similar to the Byron plant in Ogle County. In response, inspections were initiated at the Byron generating station, where tritium leaks were also discovered.

Tritium is a byproduct of producing electricity in nuclear reactors. Its release to the environment is permitted at levels regulated by the federal government.

Braidwood and Byron both use a blowdown line to release tritiated water to the Kankakee and Rock rivers. The line includes concrete vaults with valves known as vacuum breakers that can malfunction and leak. Exelon reported that water in the Byron vaults was tested and found to contain tritium concentrations of 86,000 picocuries per liter. Tests are being run to determine if the tritium has leaked into ground water on the plant site. According to Exelon, the Byron tritium concentrations pose no health or safety threat to employees or the public.

The Illinois EPA is doing its own study at Byron and will not comment about health or safety threats until they have completed their study.

The Byron assessment is part of a new program to assess pipes, pumps, valves, tanks and other pieces of equipment that carry tritiated water in and around the plant. In addition to the inspection program, a separate project team is looking for technological ways to reduce the amount of tritium produced and released at all Exelon nuclear plants.

Exelon publicly revealed that four leaks occurred at the Braidwood plant between 1996 and 2003. According to a Chicago Tribune article, the Illinois EPA learned of a 2000 spill in March 2005, when a local official asked the agency to investigate the situation.

Exelon has drilled 158 monitoring wells at Braidwood to determine how far the plume has spread and has offered to test the wells of 28 adjacent property owners. They also bought out one nearby property owner and offered 14 others compensation for any loss in the value of their homes.

The Nuclear Regulatory Commission is investigating whether the leaks constitute a violation of nuclear safety regulations.

The Illinois EPA is considering whether a well on company property exceeds federal health standards for tritium, and whether a private well with levels above natural background levels but below health safety standards violates any state standards.

In Grundy County, Exelon revealed tritium was also detected in a well on their Dresden plant property. Up to 650,000 gallons of water containing tritium leaked from underground pipes.

The U.S. Environmental Protection Agency has established a safe drinking water limit of 20,000 picocuries of tritium per liter of water. At one test site at the center of the Dresden property, tritium levels reached 500,000 picocuries per liter. Test wells 10 to 20 feet away from the center indicate tritium levels dropping to 20,000 picocuries per liter or less. At the boundaries of the site, Exelon reported no tritium found.

Local political leaders and environmental activists have expressed alarm that Exelon waited years before going public with the information regarding tritium leaks. As quoted in the Chicago Tribune, Will County Board Chairman James Moustis questioned why Exelon did not publicly disclose the tritium spills as soon as they occurred in 1998 rather than wait years before telling the public. He raised similar concerns about the NRC’s, the Illinois EPA’s and the Illinois Department of Nuclear Safety’s failure to require a faster response to the spills.

The Nuclear Energy Information Service in Evanston, a long-standing critic of nuclear power, is particularly concerned over the eight-year delay in notifying the public about the tritium leaks. They call for a 24-hour notice regarding any leaks or spills on or off site to all local, municipal or county officials.

According to a background paper about tritium developed by Argonne National Laboratory, tritium is a naturally occurring radioactive isotope of hydrogen. Its most common forms are tritium gas (HT) and tritium oxide or “tritiated water,” the form occurring in the leaks around the nuclear power plants. It has a half life of 12 years, and emits beta particles as it undergoes radioactive decay.

While tritium is formed by natural processes, background levels have increased about five times as a result of nuclear weapons testing. It is also produced by nuclear power plants and nuclear fuel reprocessing plants. A Byron-sized nuclear power plant produces about 2 grams per year or 20,000 curies of tritium. Most of it is incorporated into the nuclear fuel and cladding. Small amounts are permitted to be released to the atmosphere and discharged with cooling water to the Rock River.

Tritium is present in surface waters at levels ranging from 10 to 30 picocuries per liter. The maximum level in drinking water allowed by the Environmental Protection Agency is 20,000 picocuries per liter.

Tritium can enter the body through eating, drinking, breathing or the skin. Once it enters the body, it quickly enters the bloodstream and disperses throughout all body fluids within two hours. It is eliminated with a biological half life of 10 days. During its time in the body, a small amount of it is incorporated into organic molecules.

The health hazard from tritium results from ionizing radiation released by radioactive decay which damages living cells. Although it is considered one of the least dangerous radioactive substances, prolonged exposure increases the risk of cancer and genetic damage.

From the Feb. 22-28, 2006, issue

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