© Charles Rex Arbogast/APA decoy sits on Bob Scamen's pond in Braidwood, Ill., within view of the Braidwood Nuclear Power Station in Braceville, Ill. Braidwood has leaked more than six million gallons of tritium-laden water in repeated leaks dating back to the 1990s — but not publicly reported until 2005.
Braceville, Illinois - Radioactive tritium has leaked from three-quarters of U.S. commercial nuclear power sites, often into groundwater from corroded, buried piping, an Associated Press investigation shows.
The number and severity of the leaks has been escalating, even as federal regulators extend the licenses of more and more reactors across the nation.
Tritium, which is a radioactive form of hydrogen, has leaked from at least 48 of 65 sites, according to U.S. Nuclear Regulatory Commission records reviewed as part of the AP's yearlong examination of safety issues at aging nuclear power plants.
Leaks from at least 37 of those facilities contained concentrations exceeding the federal drinking water standard - sometimes at hundreds of times the limit.
While most leaks have been found within plant boundaries, some have migrated offsite. But none is known to have reached public water supplies.
Comment: Tritium - is a radioactive isotope of hydrogen. The nucleus of tritium (sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of protium (by far the most abundant hydrogen isotope) contains one proton and no neutrons. Naturally occurring tritium is extremely rare on Earth, where trace amounts are formed by the interaction of the atmosphere with cosmic rays. The name of this isotope is formed from the Greek word "tritos" meaning "third."
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Health risks
Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it is a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin. HTO has a short biological half life in the human body of seven to 14 days, which both reduces the total effects of single-incident ingestion and precludes long-term bioaccumulation of HTO from the environment.