By John LaForge
A damaged and leaking three-inch pipe at Xcel Energy’s single reactor at Monticello, Minnesota on the Mississippi River, is causing a radioactive pollution problem.
Last November, radioactive tritium leaking from the 52-year-old unit was found in a company’s onsite monitoring well. Xcel waited until mid-March to report the month-long 400,000-gallon leak. Inspectors from the Nuclear Regulatory Commission (NRC) just winked at the company’s four-month delay in reporting the leak. Xcel soon claimed to have plugged the leak.
The Associated Press (AP) reported that in November the concentration of tritium “was about 5 million picocuries per-liter” in groundwater within the company’s boundaries, according to Xcel’s website. This is 250 times the amount (20,000 picocuries per liter) of tritium legally permitted in drinking water. After claiming the leak to be fixed, Xcel reported a second leak of several hundred gallons of tritium-contaminated water which the firm said had sprung from an overflow tank used to collect the first leaked wastewater.
Originally licensed in 1971 to operate 40 years, Monticello was designed to close in 2010. Yet the NRC issued Xcel a license extension in 2006, allowing it to run until September 2030.
Monticello’s aged pipes, like 23 other Fukushima-style, General Electric Mark I reactors operating in the United States, are worn out and corroded — a chronic, nationwide hazard. “Radioactive tritium leaks found at 48 U.S. nuke sites,” was a headline in a four-part AP investigative series titled “Aging Nukes,” written by Jeff Dunn in 2011. “You got pipes that have been buried underground for 30 or 40 years, and they’ve never been inspected, and the NRC is looking the other way,” engineer Paul Blanch (who had worked for the industry and later became a whistleblower), told Dunn. “They could have corrosion all over the place,” Blanch said.
The Star Tribune reported June 17 that, “Tritium leaks unfortunately have been relatively common in the nuclear industry, and the Monticello spill was among the nation’s 10 largest.”
NRC public affairs officer Prema Chandrathil replied August 10 to some questions from Nukewatch, writing, “The now-stopped leak was from a pipe that ran between two buildings on site where the water had already been processed, filtered, and demineralized.” Asked if there were other radioactive materials in the wastewater, Chandrathil wrote, “When the leak was going on there were low levels of xenon and iodine detected near the leak. They decay away and become non-radioactive quickly due to their short half-life. Therefore, tritium is the only type of radioactive material currently present in the groundwater.”
This answer is suspect. Iodine-125 has a 60-day half-life, and, because it takes ten half-lives to “decay away,” its gamma radiation spews for 600 days. Iodine-129 has a half-life of 16 million years. If the NRC official meant iodine-131 — Chandrathil didn’t specify — that isotope decays for 80 days. Neither does xenon-137 just “decay away” as the NRC public affairs officer said. It decays to cesium-137 which takes 300 years to “decay away.” Again Chandrathil didn’t report which isotope of xenon was leaking, Xe-133, Xe-137, or some other.
The Minn. Dept. of Health website report on this event notes, “A conservative assumption in radiation protection is that any radiation exposure could result in an increase in cancer occurrences in the population, with the risk increasing as exposure increases.” However Xcel has said there is “no” health risk to the public as the affected groundwater contains “very low levels” of tritium.
This reassurance is untrue. Even “very low levels” of radiation exposure create a risk as the Health Dept. noted. Radiobiologists all agree that we can no longer speak of a ‘safe’ radiation dose level. And every federal agency that regulates industrial releases and medical uses of ionizing radiation warns that exposure to radiation (external or internal), no matter how small, increases one’s risk of cancer and other illnesses. For example, the Environmental Protection Agency says, “There is no firm basis for setting a ‘safe’ level of exposure above background ….”, “Based on current scientific evidence, any exposure to radiation can be harmful (or can increase the risk of cancer). …. no radiation exposure is completely risk free.” And “[T]here is no level below which we can say an exposure poses no risk.”
Tritium emits ‘beta’ radiation in the form of fast- moving particles, and several sources misreported related facts. The Minn. Dept. of Health said July 21, that beta particles “are too weak to penetrate the skin,” and the AP reported last March 17 that tritium’s beta radiation “cannot penetrate human skin.”
The Environmental Protection Agency and many other authorities say beta particles are “more penetrating than alpha particles,” and “are capable of penetrating the skin and causing radiation damage.” Dr. Rosalie Bertell in her book No Immediate Danger says beta particles can cause serious burns and other skin anomalies, including skin cancer. If beta particles are inhaled or ingested, they can cause biological damage more severe than external exposure inflicts because they can penetrate cell membranes.
In an apparent admission that Xcel has lost control of the underground radioactive plume moving toward the Mississippi, the firm announced August 17 that it would build an “underground metal barrier” between the leaking pipe(s) and the river. Xcel said the steel wall — 40-feet deep and 600 feet long — will take four to eight weeks to install “along the edge of the plant’s boundary with the river,” and is intended to keep Monticello’s contaminated groundwater from reaching the Mississippi River. Authorities have not reported whether the groundwater plume is deeper than 40 feet.
One grim irony of Xcel’s underground wall is that at Japan’s Fukushima-Daiichi — where three identical GE reactors, were destroyed by earthquake damage and meltdowns — the owners tried to retard the flow of groundwater by constructing an underground wall. The Japanese effort failed even after a $250 million investment. In addition, like at Fukushima where huge steel tanks currently store 1.37 million tons of contaminated wastewater, Xcel said last March that it was “considering building above-ground storage tanks” for its radioactively tainted leaks.