Tritium Leaks at Monticello Nuclear Reactor: It Ain’t Just Hydrogen

By Kelly Lundeen

The word ‘tritium’ dotted regional headlines this year, accompanied by misleading information about the radioactive substance. The March 17, 2023 weekly edition of Monticello Times announced, “400,000 gallons of water contaminated with radioactive tritium leaked from Monticello nuclear power plant.” Again on March 23, the Times followed up, “Xcel, regulators knew of tritium leak four months before notice.” On March 16, the St. Paul Pioneer Press assured the public that “Regulators monitor tritium leak at Xcel Energy’s Monticello nuclear plant.”

The large radioactive water leak at a concentration of 5 million picocuries-per-liter (pCi/L) of tritium was discovered one year ago by the Monticello reactor’s operator, Northern States Power. Four months later a second leak appeared when the fix failed. This forced the reactor to be shut down for a week, prompting regulators to finally release information about the leak to the public.

Xcel claims to have fixed the leak and continues pumping and collecting the radioactive groundwater to store onsite for reuse. The firm is also building a 600-foot underground wall 20 feet from the Mississippi River to prevent the radioactive groundwater from entering the River, even though, on July 20, Minnesota Public Radio warned, “Xcel: Leaked groundwater containing tritium may have reached Mississippi River in Monticello.”

Xcel has dodged questions about how far the radioactive water could have spread. The company claims that no tritium has been detected beyond the reactor facility boundaries, nor entered the Mississippi River, yet it has never specified where its testing is being done. Groundwater moves between 1 foot-per-day and 1 foot-per-decade, but the Mississippi River in Minnesota flows about 12,000 cubic feet-per-second, which could quickly disperse the tritiated water. Groundwater typically provides about 40-50 percent of the surface water to rivers, meaning the contaminated groundwater could have entered the Mississippi without being detected depending on where water is tested.

What is tritium?

What is this radioactive isotope that made headlines in mainstream newspapers? Tritium is a radioactive isotope of hydrogen. Much of the news coverage about the tritium leak at the Monticello reactor is deceptively reassuring. Mainstream media parrot misleading myths about tritium peddled by industry and the Nuclear Regulatory Commission (NRC).

Myth # 1

“Tritium is safe because it is ‘naturally occurring’ in the environment,” Pioneer Press, March 16

While it is true that tritium occurs in nature, its only natural source is in the upper atmosphere. In the chart below you can see that estimated naturally occurring tritium in groundwater — deposited from the upper atmosphere — ranges from 6 to 26 pCi/L. Additional tritium has been dispersed due to atmospheric nuclear weapons tests and routine or accidental nuclear reactor discharges.

Myth #2

“Tritium emits a weak form of radiation, a low-energy beta particle,” NRC

Radiation from tritium is not low-energy, but rather low-range, and its emissions are concentrated in a small space. It can be eight times more biologically damaging than other types of radiation if ingested or inhaled, and can even incorporate into DNA molecules affecting chromosomes.

Myth #3

“Tritium is a mildly radioactive form of hydrogen that occurs naturally,” Minnesota Public Radio, August 17

Tritium atoms replace hydrogen atoms in water molecules making the water itself radioactive. It is not simply water with tritium, it is tritiated water. Once it is part of water it follows the water cycle, traveling through groundwater, absorbed by roots of plants and into our food, or evaporated into the atmosphere and returned to the Earth through precipitation.

The body cannot distinguish clean water from tritiated water, making it more dangerous than other radionuclides. Its capacity to be exchanged with hydrogen gives it the special ability to bind with organic materials in plants, food, humans, and other animals.

Hydrogen is one of the building blocks of the human body and of all life. Humans are about 60 percent water. Tritium, disguised as hydrogen, is therefore more dangerous due to its similarity to hydrogen, not less dangerous. When a fetus is growing, its tissue collects tritium at twice the concentration of maternal tissue.

Around nuclear power facilities, children are the ones who suffer the most. They are about one and a half times more likely to be born with embryonal cancer and have over double the likelihood of childhood leukemia, caused by standard operation alone. That doesn’t include the accidents.

Myth #4

“The tritium radiation does not travel very far in air and cannot penetrate the skin,” NRC

Soil, plants, and food grown near nuclear reactors have been found to be contaminated up to 60 miles from the reactor site. In the case of Monticello, this includes the entire Minneapolis/St. Paul metro area, a population of 4 million people.

Tritium is created as a byproduct in the coolant inside the reactor core. While it may not be able to penetrate skin, there are other points of exposure that make a protective layer of skin irrelevant. Tritium is released legally by regular operation of all nuclear reactors in the form of radioactive water vapor. As long as people living around the reactor breath, the tritium will be inhaled, easily bypassing the skin. It can also be ingested through consumption of food grown around the reactor.

This article would not have been possible without information collected from radiation classes offered by the Gender & Radiation Information Project and Beyond Nuclear. (genderandradiation.org/classes)

— Sources include: Xcel Energy Monticello Groundwater Status and Background, Nov. 21, 2022; Minn. Public Radio, April 24, 2023; United States Geological Society (USGS) National Ground-Water Monitoring Network 2008, 1998; “Treatise on Geochemistry,” Volume 5, 2003, Pages 319-364, published by USGS, 2003