Corrosion Causing Leaks at Most US Nuclear Sites

Written by on June 24, 2011 in Corrosion News, Nuclear - No comments
Print Friendly

Radioactive tritium has leaked from three-quarters of United States commercial nuclear power sites, often into groundwater from corroded, buried piping, an Associated Press investigation shows.

And the number and severity of the leaks has been escalating, even as federal regulators extend the licences of more reactors across the US.

Tritium, which is a radioactive form of hydrogen, has leaked from at least 48 of 65 sites, according to US Nuclear Regulatory Commission records reviewed as part of AP’s year-long examination of safety issues at ageing 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.

At three sites – two in Illinois and one in Minnesota – leaks have contaminated drinking wells of nearby homes but not at levels violating the drinking water standard. At a fourth site, in New Jersey, tritium has leaked into an aquifer and a discharge canal feeding a bay on the Atlantic Ocean.

The US Environmental Protection Agency says tritium should measure no more than 20,000 picocuries per litre in drinking water.

It also estimates seven of 200,000 people who drink such water for decades will develop cancer.

The tritium leaks have also spurred doubts among independent engineers about the reliability of emergency safety systems at the 104 nuclear reactors situated on the 65 sites.

However, federal and industry officials say the tritium leaks pose no health or safety threat. Tony Pietrangelo, chief nuclear officer of the industry’s Nuclear Energy Institute, said impacts were “next to zero”.

Corrosion has occurred for decades along the hard-to-reach, wet underbellies of the reactors – generally built in a burst of construction during the 1960s and 1970s. An industry document said 38 leaks from underground piping had been found between 2000 and 2009 with nearly two-thirds of those being reported during the past five years.

Subsurface water not only rusts underground pipes but attacks other buried components, including electrical cables that carry signals to control operations.

A 2008 NRC staff memo reported industry data showing 83 failed cables between 21 and 30 years of service – but only 40 within their first 10 years of service.

AP found the leaks sometimes go undiscovered for years.

Many of the pipes or tanks have been patched, and contaminated soil and water have been removed in some places. Mistakes and defective material have contributed to some leaks but corrosion is the main cause. And, safety engineers say, the rash of leaks suggest nuclear operators are hard put to maintain the decades-old systems.

The Union of Concerned Scientists reported in September that more than 400 known radioactive leaks of all kinds of substances had occurred over the history of the US industry.

Nuclear engineer Bill Corcoran said that since much of the piping was inaccessible and carried cooling water, the worry was if the pipes leaked there could be a meltdown.

Mario Bonaca, a former member of the NRC’s advisory committee on Reactor Safeguards, said: “Any leak is a problem because you have the leak itself – but it also says something about the piping. Evidently something has to be done.”

An NRC taskforce on tritium leaks last year dismissed the danger to public health. Instead, its report called the leaks “a challenging issue from the perspective of communications around environmental protection” but admitted they had “impacted public confidence”.

The industry has also been trying to stop the leaks by drilling more monitoring wells and replacing old piping. So far, 66 reactors have been approved for 20-year extensions to their original 40-year licenses, with 16 more extensions pending.

Regulators and industry have also worked in concert to loosen safety standards to keep the plants operating.


Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Leave a Comment