Another radioactive leak reported at York Co. nuclear station

Water with traces of a radioactive hydrogen isotope has again leaked at a South Carolina nuclear power plant.

But the U.S. Nuclear Regulatory Commission says the level of tritium in the water is well below limits that would make it dangerous to drink.

The NRC says more than 100 gallons of water containing tritium leaked over the weekend during maintenance at the Catawba Nuclear Station in York County.

An incident report on the NRC's website says the leak happened on Saturday night around 11:30 p.m. It was reported to the NRC on Monday afternoon.

"While conducting planned Unit 2 maintenance activities, water from the main condenser was being pumped to a site collection pond and overflowed due to exceeding capacity," the incident report states. "The source of the spill was stopped. Based upon the on-site spill location and low tritium levels, there is no health or safety risk to the public or employees."

Tritium is a radioactive form hydrogen by bonding together three hydrogen atoms. WBTV has learned the atoms take just over 12 years to break down.

The report states the levels were less than one-half of the US Environmental Protection Agency drinking water standard for tritium.

"Everyone is exposed to small amounts of tritium every day, because it occurs naturally in the environment and the foods we eat," according to the  U.S. Nuclear Regulatory Commission's website. 

Officials say water was being pumped to a collection pump, and the water in the pond overflowed.

Duke Energy says the contaminated water was not near drinking water wells. In May, a leak in a discharge pipe resulted in a spill of more than 100 gallons of water.

"This is not anything that causes us any level of concern," York County Emergency Management Director Cotton Howell told WBTV about the May leak. "There's certainly no immediate risk. All the testing will be done and appropriate action will be taken. The likelihood of this actually getting into the ground water is rare."

"Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the soft tissues," the NRC's website stated. "Half of the tritium is excreted within approximately 10 days after exposure."

The U.S. Environmental Protection Agency says drinking water containing tritium can increase cancer risk.

According to Duke Energy, Tritium must be ingested in large quantities to pose any significant health risks.

Copyright 2013 WBTV. The Associated Press contributed to this report. All rights reserved