Radioactive tritium found in ice outside Hope Creek

The latest cold snap has delivered a troubling surprise at PSEG Nuclear’s Salem/Hope Creek reactor complex: Discovery of radioactive tritium in snow and ice outside a Hope Creek building at levels 500 times higher than federal water quality standards.

At an estimated 10 million picocuries per liter in a confined area, it was the second-highest concentration reported in any tritium leak and pollution incident nationwide. Only a 15 million picocurie high at nearby Salem ranks higher, recorded during investigations of a leak and continuing, serious groundwater contamination problem that dates to 2002.

The federal drinking water limit for tritium, an isotope of hydrogen, is 20,000 picocuries per liter.

Although there was no clear origin or evidence the radioactive material had moved offsite, the unexplained finding was a “high reading” and cause for company and regulator concern, said David Lochbaum, a nuclear engineer and nuclear safety program director for the Union of Concerned Scientists.

“Fortunately, the mystery will be solved, probably before anything can get offsite and cause harm,” Lochbaum said. He added that in two other episodes in the past, airborne releases were found to have concentrated on rooftops before reaching the ground, although no evidence has been found to date pointing to a similar origin at Hope Creek.

Federal regulators and the company provided details on discovery of the mildly radioactive material on the same day that the Nuclear Regulatory Commission made public plans for a special inspection at Salem Unit 1 triggered by an excessive number of emergency or unplanned shutdowns over the past several quarters.

Investigators said the tritium at Hope Creek was detected below snow and ice hanging from a building during routine sampling on Thursday. Radiation monitors were showing normal conditions at the time, and tests of nearby vents the day before found normal tritium traces, according to the NRC.

“As such, there are no obvious potential unmonitored release paths that could account for the reading,” said Neil Sheehan, spokesman for the NRC’s regional office near Philadelphia. “No possible cause for the elevated tritium reading has yet been identified. Also, no increased tritium levels have been detected in a groundwater monitoring well located where the snow/ice sample was taken.”

Joe Delmar, spokesman for PSEG Nuclear, said workers conducting routine tritium sampling found the contamination.

“Once identified, appropriate corrective actions were taken to mitigate the small impacted area including clearing ice from a five foot section of the paved surface located at the northeast corner of the building,” Delmar said. “In addition, a containment device was added to capture any more dripping water.”

An investigation is under way, Delmar said. No groundwater threats have been identified, he added, and no connections have been found to a longstanding tritium release to groundwater at the nearby Salem Unit 1 area.

A picocurie is a measure equal to one-trillionth of a curie. A curie is one standard measure of radiation intensity, and is roughly equal to that found with a gram of a particular type of radium. The hydrogen isotope called tritium is one of the lower-energy and shorter-lived radioactive materials; NRC reports say that humans usually excrete tritium within 10 days of exposure.

Although the detection at Hope Creek was much higher, a dose from consuming water at 1,600 picocuries per liter, the NRC has reported, is 1,000 times lower than exposure to natural background radiation, and 12 times lower than the amount absorbed during a round-trip, cross-country flight.

Before 2006, Lochbaum said, nuclear plant operators had no such monitoring for tritium – a fact that changed when the Braidwood reactor site near Joliet, Ill., contaminated groundwater used for drinking supplies in hundreds of homes.

An estimated six million gallons of tritium-tainted water was found to have leaked from the plant in more than a dozen incidents with owner Exelon offering bottled water to some residents and in some cases buying homes affected by the spill.

“Some of that leaked into people’s drinking wells. It didn’t kill anybody, but that was more luck than skill,” Lochbaum said. “That’s what really drove the industry to better monitoring.”

Then-Democratic Illinois Sen. Barack Obama, Lochbaum said, introduced legislation in response to the leaks that “industry didn’t like,” spurring plant owner agreements to adopt a new monitoring program.

PSEG has been wrestling with tritium leak and groundwater contamination at a nearby Salem reactor area for more than a decade. The company recently reported that the radioactive material had found its way into a deeper aquifer under the containment building despite earlier company denials that the material had worked its way so far down.

In a twist, the company currently prevents tritium from spreading in groundwater by using a network of wells to hold back contaminated plumes, with the recovered, tritium-laced water simply pumped to the Delaware River for quick dilution.

Delmar said separately that the company expected the NRC’s finding and inspection requirement connected with the recent unplanned shutdowns.

The Salem/Hope Creek reactor site on Artificial Island ranks as the nation’s second-largest nuclear power center, with three plants on a 740-acre site capable of producing up to 3,485 megawatts. Delaware residents account for the majority – more than 45,000 people – living inside the operation’s 10-mile emergency planning zone. The Delaware evacuation zone number is expected to rise to 68,000 by 2025.

NRC officials are currently reviewing an application from PSEG for approval of a site for construction of one or more new reactors. Company officials have not chosen a technology or individual plant capacity for any new project – which would cost several billion dollars. A separate permit would be required for construction and operation.

Contact Jeff Montgomery at 463-3344 or jmontgomery@delawareonline.com.