Tests show no leaks at Nuclear One plant
Posted on Friday, January 12, 2007
Recent groundwater tests at Arkansas Nuclear One found no signs of elevated radioactivity as the nuclear power industry responds to a series of tritium leaks found nationwide since 2003.
At least seven of the nation’s 103 nuclear reactors, which provide about one-fifth of the nation’s electricity, have had radioactive water seep into groundwater undetected. Similar leaks also surfaced at two idled facilities.
According to the Union of Concerned Scientists some leaks were undetected for up to 12 years.
As a result, the Nuclear Energy Institute, the industry’s lead policy group, has agreed to make regular groundwater checks at all plants and report its findings to the Nuclear Regulatory Commission.
Since July, no new reports of tritium contamination have surfaced nationwide, NRC spokesman Scott Burnell said.
Tritium is one of the weakest forms of radiation, but scientists disagree on its health risks to humans.
The first tests at Arkansas Nuclear One, near Russellville and owned by Entergy Corp., concluded last month, plant spokesman Phil Fisher said.
“Last summer, we completed a geohydrology study to determine whether the water flow beneath the plant is the same [volume and direction ] as when it was constructed in the late ’ 60 s and early ’ 70 s. We found that it was, and, based on that, wells were drilled in late November to conduct groundwater sampling,” he said.
“One was drilled upstream from the plant, with three drilled downstream. We sampled all four for tritium in late December and none was detected. Going forward, we’ll do similar analyses quarterly. But for now, we’re in good shape.” So far, all U. S. nuclear plants have plans to monitor both groundwater and drinking water pathways for tritium, Burnell said.
About 87 percent have “specific” groundwater programs on-site, while the rest must complete their evaluations before monitoring begins, Burnell said.
“In terms of industry reports, they must keep us up to date,” Burnell said. Nuclear Energy Institute officials were not immediately available for comment.
Tritium is a radioactive isotope of hydrogen, according to the Environmental Protection Agency. It occurs naturally when the sun’s rays hit the atmosphere and is a byproduct of nuclear reactors that generate electricity.
Because its most common form is in water, tritium ends up in water used to cool nuclear reactors.
Tritium is commonly used in exit signs in buildings, luminescent paint, watch dials and aircraft gauges.
For plants like Arkansas Nuclear One, the regulatory limit for tritium in discharged water is 0. 003 microcuries per milliliter.
If a person drank tritiated water at the NRC limit nonstop for a year, they would ingest about 50 millirems of radiation, plant officials have said. By comparison, a coast-to-coast airline flight exposes people to about 12 millirems of radiation, while a chest X-ray involves about 2 millirems, according to the Massachusetts Institute of Technology’s Radiation Protection Office.
Even so, scientists have long debated how even small doses of radiation affect human health. In June, a National Academy of Sciences panel found that the slightest exposure to radiation brings the risk of cancer and that the risks increase with repeated exposure.
While low doses usually carry low risk, the panel concluded it is unknown exactly how much risk comes with such everyday procedures as X-ray imaging.
High tritium doses carry an increased risk of cancer or leukemia, but only if ingested, according to a 1995 study by Lawrence Berkeley National Laboratory.
So far, the worst case of tritium contamination involves the Braidwood Generation Station, about 60 miles south of Chicago.
Owned and operated by Chicago-based Exelon Corp., the plant has seen at least six occurrences since 1996 in which more than 6 million gallons of tritiated water have oozed from an underground pipe that leads to a discharge point on the Kankakee River.
Some of it seeped into groundwater used by the nearby villages of Godley and Braidwood, which have a combined population of about 5, 800.
Two leaks are cited in a lawsuit by Illinois’ attorney general that seeks more than $ 36 million — including penalties for alleged failure to report some of the leaks until December 2005.
Exelon also owns three other Illinois plants — Dresden, Byron and its idled Zion facility — where tritium leaks have been discovered. Officials at Entergy’s Indian Point Energy Center near Buchanan, N. Y., also are still trying to pinpoint the source of radioactive leakage near a spent-fuel storage tank.
In October, the NRC stated that no public health impact has come from unmonitored radioactive releases at any commercial nuclear plant since 1996.
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