TMI Update: Jan 14, 2024

Perhaps the easiest path to making a nuclear weapon, for a country or terrorist seeking one, is to extract a sufficient amount of weapons-grade, highly enriched uranium (HEU) from the nominally peaceful fuel in a research reactor, the small type operating in dozens of countries, including many that lack larger nuclear power plants. According to the late Manhattan Project physicist Luis Alvarez, even high school students “would have a good chance of setting off a high-yield explosion simply by dropping one half of the material onto the other half.” That is why the U.S. nearly half a century ago initiated a program to gradually eliminate such dangerous fuel from these facilities. Now, however, in a stunning reversal, the U.S. Energy Department is actually increasing the likelihood of that deadly scenario by supplying a new research reactor with enough weapons-grade uranium for a sizable nuclear arsenal.

The danger is not just hypothetical. In 1990, Iraqi president Saddam Hussein secretly ordered a crash program to extract HEU from his foreign-supplied research reactor fuel to make an atomic bomb—after his invasion of neighboring Kuwait—but a U.N. intervention fortunately evicted his troops and interrupted the plot before it could succeed.

To prevent such grave risks, the U.S. government since the 1970s has spearheaded an international collaboration to eliminate HEU from research reactors by substituting low enriched uranium (LEU) fuel, the type used in nuclear power plants that is unsuitable for nuclear weapons. (LEU is enriched below 20 percent in the chain-reacting isotope uranium-235, making it unsuitable for nuclear weapons, whereas HEU fuel in research reactors typically is enriched to 93 percent, the same as in U.S. nuclear weapons.) The U.S.-led program has helped contain nuclear proliferation and prevent nuclear terrorism by converting 71 reactors in the U.S. and abroad from HEU to LEU fuel, even tiny ones containing only one kilogram of HEU. The U.S. has not built an HEU-fueled civilian reactor since the 1970s, and no other country has done so since the 1990s.

However the Biden administration intends to violate this nonproliferation policy by supplying over 600 kilograms of weapons-grade uranium—enough for dozens of nuclear weapons—to a privately owned experimental research reactor that would be largely funded by the U.S. government. If the project proceeds, other countries will insist on violating the policy too, refusing to accept a double standard. Whether they import HEU from the United States, purchase it from Russia or build their own enrichment plants, the risks of nuclear proliferation and terrorism will grow again.

The U.S. government is providing $90 million of the $113 million cost to build the Molten Chloride Reactor Experiment (MCRE), which aims to research the potential for a commercial version known as the Molten Chloride Fast Reactor. Although no such power plants exist, they would in theory employ a loop of liquid fuel—uranium dissolved in hot salt—to both sustain the fission reaction and transport the resulting heat. Advocates claim that using liquid fuel, instead of the solid fuel now used in all nuclear power plants, would be a more efficient way to produce electricity and heat for industrial uses. This is not an entirely new concept. In the 1960s, a similar Molten Salt Reactor Experiment was tried but largely failed at Oak Ridge National Laboratory—partly in consequence of the corrosive combination of salt, high temperature and radiation—and it left a particularly nasty radioactive waste problem that still persists. Six decades later, the Energy Department has decided to throw good money after bad.

The technical tweak of the MCRE is to utilize “fast” (high-energy) neutrons rather than the “thermal” (lower-energy) neutrons used in all U.S. nuclear power plants and the 1960s experiment. Fast neutrons facilitate the fission of some radioactive, human-made elements produced in reactors and so can reduce slightly the long-lived radioactivity of the nuclear waste created. But fast neutrons are much less able to induce fission in uranium-235, which is essential for the chain reaction to power the reactor. So, the fuel needs a larger percentage of this isotope, entailing higher uranium-235 enrichment than the 4 percent enriched LEU typically used in nuclear power plants.

However, molten salt fast reactors such as the proposed MCRE do not require HEU. This fact is undisputed because both the Biden administration and its private partners acknowledge that a commercial version, if ever built, would use LEU fuel.

So, if the reactor could use LEU fuel, why is the Biden administration funding an HEU version that would violate U.S. nonproliferation policy?

The last time that shortsighted U.S. officials planned to build an HEU-fueled research reactor, in the early 1990s, “opposition to the use of highly-enriched uranium in the reactor's core led to its cancellation” by President Bill Clinton. The only question is whether Joe Biden will again demonstrate such U.S. leadership, or gratuitously undermine one of the world’s most successful nuclear nonproliferation programs.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.

Xcel Energy is asking developers to submit proposals for approximately 1,200 megawatts of new wind projects.

The utility is seeking projects located in southwest Minnesota that would be commercially operable by the end of 2027. Xcel Energy said these new wind resources, combined with solar and energy storage projects, would help replace the capacity of the coal-fired Sherco plant in Becker.

The transition is part of the company’s Upper Midwest Integrated Resource Plan, approved by the Minnesota Public Utilities Commission in 2022.

The Sherco site plays an important role in Xcel Energy’s plan to cut emissions. The utility has proposed a transmission line that would deliver 2,000 MW of renewable energy to the grid at Sherco.

In April 2023, the company broke ground on a 710 MW solar project near the coal plant site. Once complete, the project would fully replace the first Sherco coal unit, which is scheduled to retire by the end of the year.

The company has also received state approval on a long-duration battery storage pilot project at Sherco.

• Prevent and shorten power outages through the addition of intelligent grid devices, sensors and automation on single-phase and underground networks. 
• Improve system reliability and reduce maintenance costs through predictive failure monitoring technology. 
• Provide real-time visibility into the grid to identify outages, changes in customer demand and fluctuations in distributed energy resources to automatically reroute power and safely balance the flow of power on the grid.
• Enable increased connections of distributed energy resources and electric vehicle adoption on the grid through IT enhancements using artificial intelligence and machine learning.  

• Prevent and shorten power outages through the addition of intelligent grid devices, sensors and automation on single-phase and underground networks. 
• Improve system reliability and reduce maintenance costs through predictive failure monitoring technology. 
• Provide real-time visibility into the grid to identify outages, changes in customer demand and fluctuations in distributed energy resources to automatically reroute power and safely balance the flow of power on the grid.
• Enable increased connections of distributed energy resources and electric vehicle adoption on the grid through IT enhancements using artificial intelligence and machine learning.  

The Massachusetts Department of Environmental Protection has sent a letter warning Holtec International about evaporating radioactive wastewater without a permit.

The letter, which was dated September 25—but not mentioned at a meeting of the Nuclear Decommissioning Citizens Panel that same day—says any such evaporative methods, “may be subject to MassDEP air quality permitting.”

Experts at that meeting talked about the “new” method of eliminating some of the remaining water in the spent fuel pool by using heaters to evaporate the water and vent it into the air.

The amount of radiation released into the atmosphere would be minimal, the experts said.

The warning letter to John Moylan, Holtec’s site vice president, says, however, that Holtec—the company decommissioning the Pilgrim Nuclear Power Plant—may also be in violation of the federal Clean Air Act and other US Environmental Protection Agency regulations.

The letter was written by Seth Pickering, MassDEP’s deputy regional director for the southeast region.

Mr. Pickering referred media questions to Edmund Coletta, a spokesman for the department. Mr. Coletta said the emissions already released did not trigger any alarms, but that future releases should be discussed with MassDEP.

More specifically, Mr. Coletta said in an email yesterday that “emissions related to the recent use of immersion heaters are not subject MassDEP air permits for the facility and did not trigger any threshold that would have required Holtec to apply for a permit.”

He added, however, that “MassDEP has informed Holtec that prior to implementing any potential plan to dispose of water through evaporation, they need to contact MassDEP to discuss the potential applicability of any air quality permitting requirements.”

Meanwhile, environmentalists following the Holtec decommissioning process said they were pleased to see the DEP letter.

“It’s important that the state is stepping up to protect our environment,” said Diane Turco, founder and director of Cape Cod Downwinders, an environmental watchdog group.

Ms. Turco said she received a copy of Mr. Pickering’s letter on Friday, October 6.

“I don’t know why this was not discussed at the NDCAP meeting, but I’m glad the state is taking a stand,” Ms. Turco said.

Ms. Turco was also the recipient of an anonymous letter in August, apparently from a Holtec employee, that spelled out Holtec’s intention to evaporate the toxic wastes into the atmosphere through the power plant’s ventilation system.

It was reported that Holtec installed nine of the heaters at Pilgrim in March and used them through June to heat the irradiated water to 117 degrees.

Holtec, which has said it has discontinued evaporating wastewater, had previously raised the ire of environmentalists, residents and legislators with its proposal to discharge more that one million gallons of irradiated water into Cape Cod Bay.

Besides discharging the water into the bay or evaporating it, Holtec has two other options: ship the waste offsite to an underground storage facility; or store it in casks at the power plant.

Residents and legislators overwhelmingly prefer the option of shipping the wastes offsite.

Holtec has maintained that it should be allowed to discharge the wastewater into Cape Cod Bay because, the company has said, the radiation levels are too low to cause damage to people or sea life.

The company has also said that discharging wastes into the bay has taken place many times over the years, with no ill effects.

The Massachusetts Department of Environmental Protection has tentatively denied a discharge permit to Holtec and recently concluded a public comment period soliciting opinion about making the discharge denial permanent.

The department received more than 700 responses and is expected to make a determination in the coming weeks, a spokesman said at the Monday meeting.

The state DEP has focused on the state’s Ocean Sanctuaries Act as the legal basis to deny Holtec’s permit to discharge the nuclear wastewater into the bay.

A legal team hired by the environmental watchdog group, the Association to Protect Cape Cod, found that the Massachusetts Ocean Sanctuaries Act of 1971 prohibits dumping or discharging industrial wastes into protected Massachusetts waters.

Barry Potvin, chairman of the Plymouth Board of Health, was among many who have expressed concern about the release of specific pollutants.

“We’re concerned about tritium, which cannot be removed by any means,” Dr. Potvin has said.

The Nuclear Regulatory Commission, which is charged with overseeing nuclear power plant decommissioning, has said the concerns are overblown.

“All reactors have spent fuel pools. The releases happen, they are pretty much unavoidable,” Harold W. Anagnostopoulos, the Nuclear Regulatory Commission’s lead decommissioning inspector at Pilgrim said at a recent public forum.

“The amount of tritium and other nuclear particles released would be “insignificant,” Mr. Anagnostopoulos said.

Other experts have said that the evaporation method is especially dangerous because the discharge is difficult to measure and there is no filtration system used.

“Even very low doses can cause lifelong damage and increase the risk of cancer over a lifetime,” said Dr. Brita Lundberg, speaking on behalf of the members of the Greater Boston Physicians for Social Responsibility, an organization that monitors public health risks.

Patrick O’Brien, Holtec’s director of government affairs and communications, said Holtec has not responded to MassDEP’s letter.

Mr. O’Brien has said, however, that evaporation of wastewater is routine.

“Evaporative releases are monitored and part of our annual environmental reporting and have occurred continuously since the plant began operations in 1972,” Mr O’Brien said last month.

MassDEP has not yet determined whether Holtec’s discharge permit should be permanently prohibited, Mr. Coletta said, and no date for the decision has been announced.

The state department of public health continues to monitor samples taken from Pilgrim during the decommissioning process, Mr. Coletta said.