Thorium power is the safer future of nuclear energy

Nuclear power has long been a contentious topic. It generates huge amounts of electricity with zero carbon emissions and, thus, is held up as a solution to global energy woes. But it also entails several risks, including weapons development, possible meltdown and the hazards of disposing of its waste products.

However, those risks and benefits all pertain to nuclear energy by fission of uranium or plutonium isotopes. There’s another kind of nuclear energy that’s been waiting in the wings for decades: nuclear fission using thorium, a fuel that is estimated to be about four times more abundant than uranium in the Earth’s crust. Compared with conventional nuclear energy, the hazards of a thorium-powered reactor are significantly lower.

Conventional nuclear power using a fuel cycle using uranium- 235 and/or plutonium-239 was seen as solving two problems: reducing America’s dependence on foreign oil and creating the fuel needed for nuclear weapons. Thorium power, on the other hand, doesn’t have military potential, which has led global leaders worried about nuclear technology leading to proliferation of weapons to take a closer look at thorium power generation.

In a thorium reactor, naturally occurring Th-232 is bombarded with a beam of neutrons from a neutron generator. By capturing a neutron, it becomes Th-233, which decays to protactinium-233, which further decays into U-233. The U-233 remains in the reactor and the fission of the uranium generates intense heat that can be used to produce electricity.

There is no nuclear chain reaction from the fuel, so there is no need for control rods to stop the reaction. This makes the thorium reactor inherently safe by eliminating the possibility of it going out of control. A thorium reactor can be shut down by simply turning off the neutron generator. That doesn’t stop the heating in the reactor immediately, but it stops it from getting worse.

In the kind of molten-salt-cooled reactor favored by many thorium proponents, the thorium-232 fuel would be dissolved in a coolant of liquid fluoride salts contained in a graphite core. The coolant and fuel mixture from the core would be circulated through a heat exchanger, so that the heat energy can be extracted to power a turbine and generate electricity.

One advantage of this system is that the fluoride salt coolant has a boiling point far higher than the reactor’s operating temperature of about 750 degrees Celsius. Therefore, the whole system can operate at close to atmospheric pressure. In a conventional water-cooled reactor, the cooling system must with-stand high pressure and expensive containment structures are required to minimize the danger from pressure explosions.

Thorium fuel can also be used in current pressurized water reactors to boost safety and provide much greater fuel efficiency. Current nuclear plants extract only about three to five percent of the energy in uranium fuel rods, whereas about 98 percent of thorium fuel is consumed. One ton of thorium fuel is estimated to deliver the same amount of energy as 250 tons of uranium fuel in a pressurized water reactor.

Thorium power has other attractions, too. Its production of nuclear waste would be one hundredth or less than conventional nuclear power because most of the fuel is consumed. Thorium also yields waste that is much less radioactive, with most of it becoming inert within 30 years and about 17 percent needing secure storage for some 300 years. In contrast, the most dangerous waste from current reactors requires storage for 10,000 years.

There are some more technical drawbacks to thorium power. For one thing, molten-salt thorium reactors have been criticized as potentially having more neutron leakage compared with conven-tional reactors. More neutron leakage means that more shielding and other protection is needed for workers at the power plant. But the obvious advantages seem to outweigh the disadvantages.

Uranium-poor India has a research effort on the technology under way and has decided thorium will become the mainstay of its nuclear energy industry later this century. China has announced that its researchers will produce a fully functional thorium reactor within the next 10 years. Norway is currently in the midst of a four-year test of using thorium fuel rods in existing nuclear reactors. Other nations with active thorium research programs include Canada, the United Kingdom, France, Germany, Japan and Israel. And companies in the United States and elsewhere are working on reactor designs or thorium fuel technology.

The investments by these countries suggest that thorium power is on its way to contribute to the electrical grid in the near term and to dramatically improve the world’s energy sustainability. The future may require us to reconsider our attitudes toward nuclear power.

– compiled and edited from Discover, Jan. 16, 2015, and Reuters
PeaceMeal, March/April 2015

(In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.)


As reactors age, the money to close them lags

The operators of 20 of the nation’s aging nuclear reactors, including some whose licenses expire soon, have not saved nearly enough money for prompt and proper dismantling. If it turns out that they must shut down, the owners intend to let them sit like industrial relics for 20 to 60 years while interest accrues in the reactors’ retirement accounts.

Decommissioning a reactor is a painstaking and expensive process that involves taking down the huge structures and transporting the radioactive materials to the few sites around the country that can bury them. The cost is projected at $400 million to $1 billion per reactor.

Mothballing the plants leaves open the possibility that radioactive contamination in the structures could spread. While the radioactivity does decline over time, many communities worry about safe oversight of the defunct facilities.

Bills that once seemed far in the future may be coming due. For example, the license for Vermont Yankee in Vernon, Vt., the nation’s oldest operating reactor at 40 years, expired on March 21. And while the Nuclear Regulatory Commission has granted its owner, Entergy, a new 20-year permit, the State of Vermont is trying to close the plant. Entergy is at least $90 million short of the projected $560 million cost of dismantling it.

Of the 20 reactors that lack the money for swift dismantling, the owners hope that license renewals from the Nuclear Regulatory Commission will make the problem go away. For plants that are fighting with their host states, the federal courts may have the final say on whether and how long they keep operating. The remaining 84 active reactors have enough savings on hand to satisfy the NRC’s minimum financing requirements for eventual dismantling.

Twelve reactors across the country have been retired in the last three decades, all on short notice, because of a design or safety flaw that the economics did not justify fixing. The low price of natural gas, a competing fuel, now makes the economic lifetime of existing reactors uncertain.

Some reactors have been decommissioned in a reasonable time, like Connecticut Yankee, whose owners, a group of New England utilities, footed the cost. Decommissioning started two years after its 1996 shutdown and was completed in 2005 at a cost of $871 million.

The nuclear industry had been counting on steady returns on the funds for retiring the reactors and did not anticipate the 2008 market crash. One plant, Palisades in western Michigan, had $598 million saved up at the end of 2006, but the account was down to $219 million two years later and was only $279 million by the end of 2010, the most recent figures available.

Environmental experts say the plants can be hazardous when they are not running. The three members of Vermont’s congressional delegation pointed out that 55,000 gallons of contaminated water spilled out of a mothballed plant in Illinois after a pipe froze. An attentive night watchman was credited with catching the spill in time to contain it.

Compounding the worries about radioactive materials, the United States still lacks a permanent repository for all the spent nuclear fuel. The Yucca Mountain site in Nevada was ready to be licensed as a repository after some 20 years and $15 billion worth of work when it was scuttled by President Obama in 2011. So, the spent fuel at the sleeping reactors will remain on site indefinitely.

– edited from The New York Times, March 20, 2012
PeaceMeal, March/April 2012

(In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.)


Sleeping guards shake nuclear industry

Kerry Beal was taken aback when he discovered last March that many of his fellow security guards at the Peach Bottom nuclear power plant in Pennsylvania were taking regular naps in what they called “the ready room.” When he spoke to supervisors at his company, Wackenhut Corp., they told Beal to be a team player. When he alerted the regional office of the Nuclear Regulatory Commission, regulators let the matter drop after the plant’s owner, Exelon, said it found no evidence of guards asleep on the job. So Beal videotaped the sleeping guards. The tape, eventually given to WCBS television in New York City, showed the armed workers snoozing against walls, slumped on tabletops, or with eyes closed and heads bobbing.

The fallout of the broadcast is still being felt. In December, Exelon, the country’s largest provider of nuclear power, fired Wackenhut, which had guarded every one of its 10 nuclear plants. The NRC is reviewing its own oversight procedures, having failed to heed Beal’s warning. And Wackenhut says that the entire nuclear industry needs to rethink security, if it hopes to meet the tougher standards the NRC has tried to impose since the September 11, 2001 terrorist attacks on the United States.

The most immediate impact has been felt at Wackenhut, which protected half of the nation’s 62 commercial nuclear power plants. Exelon’s decision to terminate Wackenhut’s contract reduces the number of commercial sites protected by the company to 21. “In the past, the standards were not our standards,’ said Craig Nesbit, vice president of communications at Exelon. “They were Wackenhut standards, and that’s not what we want, and we’re going to fix that.” Exelon chief executive John W. Rowe added, “We had had some difficulties with them from time to time. We felt the incident with the guards was the last straw.”

While Wackenhut has a long history of alleged flaws in its nuclear security operations and labor discontent, there is plenty of blame to go around. The NRC, which in the past has referred 40 percent of wrongdoing allegations to nuclear plant licensees, is looking at its own procedures as well as Wackenhut’s. David Lochbaum, a nuclear safety expert at the Union of Concerned Scientists, faults the NRC for “failing to ‘connect the dots’” between Peach Bottom and other complaints about Wackenhut.

Exelon has come under scrutiny, too, from congressional and NRC investigators. Eric Wilson, the head of Wackenhut’s nuclear security operations, criticized the nuclear plant owners like Exelon. He said nuclear plant owners have pressed so hard for lower costs that “we are now down to the bone” and that “the current business model does not yield consistently acceptable performance levels.”

Wackenhut was founded in 1954 as a four-man detective agency by former FBI agent George Wackenhut, who built it into a huge private security firm with 35,000 employees. Today the company is owned by a British firm, Group 4 Securicor, and does work ranging from guarding libraries to guarding the government’s Y-12 complex at Oak Ridge TN, where nuclear weapons and materials are stored.

For Wackenhut, controversy is nothing new. The company has a history of bad relations with its workers, which some experts say could undermine security procedures. The Union of Concerned Scientists said it has received complaints dating to 2001 from Wackenhut nuclear site workers, including one who was disciplined for declining to work a sixth 12-hour shift in one week while taking medication for a back injury.

In 2006, the NRC sent inspection teams to the Turkey Point nuclear plant in Florida to check on complaints of security problems. The Union of Concerned Scientists said that unhappy Wackenhut security guards at the plant had sabotaged their own equipment.

Energy Department Inspector General Gregory Friedman has cited Wackenhut for a series of problems at the nation’s most sensitive nuclear weapons sites. In 2003, a Wackenhut employee took two government-owned handguns and one of his own in a briefcase to the National Nuclear Security Administration’s Nevada Test Site, according to an IG report.

In 2005, the Inspector General said that at the NNSA’s Oak Ridge site, Wackenhut had routinely worked security personnel more than the 60-hour-a-week maximum permitted there. Friedman’s office also found that one Wackenhut unit, hired by the NRC to simulate an attack on nuclear facilities, had tipped off another Wackenhut unit charged with guarding the facilities at Y-12 about the attack strategy. Friedman testified last summer before a subcommittee of the House Oversight and Government Reform Committee, “We did not use the word ‘cheating’ in the report, but it was. The test was compromised.”

Despite the problems, in June, Wackenhut was awarded contracts worth $549 million to protect the Y-12 National Security Complex and the Oak Ridge facility for another five years.

– edited from The Washington Post, January 4, 2008
PeaceMeal, Jan/February 2008

(In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.)