Anthony Hechanova, director of UNLV’s Transmutation Research Program, hopes that UNLV researchers and students will develop ways to transform the most dangerous materials in used nuclear fuel into safer, more stable waste that can be easily stored or recycled.

From Bad to Good

While the word 'nuclear' makes many shudder, ambitious UNLV scientists are seeking ways to eliminate the harmful byproducts of spent nuclear fuel.

By Gian Galassi

In a speech to the United Nations in 1953, Dwight D. Eisenhower outlined his vision for nuclear energy, stating that the most important responsibility for the new science was to “devise methods whereby this fissionable material would be allocated to serve the needs of mankind … of agriculture, medicine, and other peaceful purposes.”

Despite numerous advances toward this end, nuclear power still evokes for many the catastrophic images of Hiroshima and Nagasaki, the accidents at Three Mile Island and Chernobyl, and, here in Nevada, the possibility of becoming a dumping ground for the rest of the country’s nuclear waste.

But scientists and students at UNLV are developing technologies that could improve nuclear energy’s tainted reputation – research that could lead to real solutions for the nuclear industry’s most contentious problems while producing the benefits Eisenhower once imagined.

Alternatives to Deep Storage Facilities
Established in 2001 with a $3 million grant from the U.S. Department of Energy, UNLV’s Transmutation Research Program (TRP) is a multidisciplinary effort to address the ecological and economical management of the country’s used nuclear fuel. Spanning six departments in three colleges and involving more than 30 faculty members and 37 graduate students, the TRP is one of the most ambitious research efforts in the university’s history.

The program, which is administered by the Harry Reid Center for Environmental Studies (HRC), is a component of the Advanced Fuel Cycle Initiative, a national program born out of the Los Alamos National Laboratory in New Mexico. The TRP currently supports 16 separate graduate research projects, called tasks, that examine the technological requirements of a process called nuclear transmutation.
Simply defined, nuclear transmutation converts volatile, radioactive isotopes into more stable isotopes by changing their nuclear structure. This is done through neutron-induced fission or neutron-capture processes conducted in nuclear reactors or particle accelerators. The result of both fission and neutron capture in problematic isotopes is the same: the transformation of the most dangerous materials in used nuclear fuel (plutonium and other fissile materials) into safer, more stable, low-level waste, which could then be more easily managed, recycled, eliminated, or harnessed for other applications.

“Ultimately, the end result of the transmutation process is to recycle the used nuclear fuel and, at the same time, almost totally eliminate its most hazardous materials,” says Denis Beller, intercollegiate programs coordinator for the TRP and a former research scientist at Los Alamos. “In doing so, we’ll be able to decrease the overall volume of waste, lower the remaining waste’s radiotoxicity, and make the storage of the material much more secure and economical.”

Through transmutation, the life span of the most problematic materials (long-lived actinides) in nuclear waste could be reduced by as much as 95 percent – from roughly 10,000 years to fewer than 500 – thereby eliminating many of the current long-term environmental and safety concerns.

“Transmutation has the potential for completely doing away with the need for a deep geologic repository like Yucca Mountain,” says Anthony Hechanova, a nuclear engineer and director of the TRP. “It just depends how far you want go with the process. There are some concepts that look at having all waste streams classified as low-level, which would allow for their disposal at any of the many low-level waste sites around the country.”

But some significant technological obstacles must be overcome before transmutation can become reality. The research tasks the TRP has taken on are addressing some of the technical hurdles of transmutation:

• Two tasks focus on the separation of uranium and other stable elements from used nuclear fuel rods.
• Four tasks examine the fuel fabrication process that prepares some of the fission products for transmutation.
• 10 tasks are concerned with the design of specific technologies required to transmute high-level radioactive waste.

Lab technician Robert Fairhurst and Denis Beller, intercollegiate programs director for the Transmutation Research Project, discuss the electron microprobe results for a rock fragment. The microprobe does chemical analysis and X-ray mapping of materials, such as rocks from Yucca Mountain, on the submicron level.

Students and faculty from the mechanical engineering, computer and electrical engineering, physics, health physics, chemistry, and geoscience departments are conducting the research. National laboratory collaborators supervise the projects during periodic visits to campus and some also serve as adjunct professors.

“One of the most innovative aspects of our program is that our research proposals have been either co-authored or signed off on by a scientist at one of the collaborating national labs,” says Hechanova. “That way we are certain that all of our research will have direct relevance to the national program.”

It didn’t take long before this innovation proved successful.

Just two months after the program received its initial grant in 2001, students produced computer models of accelerator components that Los Alamos scientists were able to use on advanced nuclear systems. “This university has really carved out a niche for itself because of the unique structure of the program,” says Beller, who came to UNLV after serving for two years as the national project’s university programs leader at Los Alamos. “It’s completely different from any other university research collaboration I’ve seen in that it addresses the specific short-term needs of the national program instead of just conducting basic research.”

The DOE seems to agree. In a recent review, DOE officials praised the TRP for achieving quick results within such a short timeframe and have suggested modeling all other university collaborations on UNLV’s program. Among the TRP’s national partners are Los Alamos, Argonne, Lawrence Berkeley, and Oak Ridge national laboratories, as well as Idaho State, Georgia Tech, and Texas A&M universities, and the Khlopin Radium Institute in St. Petersburg, Russia.

Rapid Progress
These collaborations have allowed UNLV students to work with equipment and in facilities not available on campus, including laboratories that use highly radioactive materials and proton accelerators.

Last year, for example, mechanical engineering major Daniel Lowe spent six weeks at Los Alamos conducting experiments on one of the world’s most powerful linear accelerators. Engineering student Suresh Sadineni’s recently completed master’s thesis was based on research he conducted at the Idaho Accelerator Center at Idaho State University. Now a Ph.D. candidate at UNLV, Sadineni is developing three-dimensional computer models that simulate the nuclear reactions in subcritical reactors. He hopes to then compare the computer model results to actual reactions by using a nuclear research reactor at Texas A&M.

Hechanova admits that even he was surprised with the rapid progress of the program and the quick results of the research. “There has been such an interest in the project from faculty and students that, in a very short period of time, we accomplished more than I think any of us could have imagined,” he said. “The work that we’ve been able to do has helped make UNLV the nation’s top school in transmutation research.”

Since its inception in 2001, the TRP has received nearly $11 million in federal grants to build the human and technical infrastructure necessary to support a program of this size and scope.

TRP has added three new researchers to the program, each of whom has specific expertise in transmutation technologies and hopes to recruit two chemistry professors who are among the country’s most respected researchers in their fields.

UNLV also significantly enhanced its equipment and facilities, including the creation of two state-of-the-art laboratories and the acquisition of a transmission electron microscope (TEM) – the most powerful microscope of its kind at a university in the United States. Over the summer, new facilities were constructed to house the TEM and another piece of critical research equipment, called a Russian Loop, which will be used for the testing of lead and bismuth.

The new facilities will allow scientists at UNLV to study how liquid metals and steels will corrode and react to the chemical and mechanical stresses sustained during the transmutation process.

According to Hechanova, the new resources have allowed UNLV to emerge as the nation’s premier academic institution for transmutation research. But continued growth of the program will depend on its ability to solve the research tasks before it.

Applications Beyond Energy
Although the elimination and reduction of the harmful byproducts of nuclear energy is a considerable accomplishment, it is by no means the only benefit of transmutation. Researchers also are investigating benefits that could lead to dramatic breakthroughs in homeland security, environmental protection, energy production, and nuclear medicine and therapy.

“Used nuclear fuel is like a storage space for very rare radioisotopes,” says Beller. “Radioisotopes can be used in numerous nuclear medicine applications, including the diagnosis and treatment of specific illnesses. Scientists are continually discovering new ways to make medicines with radioisotopes that can target and kill specific cancer cells.”

Accelerator-driven transmutation has the potential to create a new large-scale source of radioisotopes, the creation of which, Hechanova says, could “bust open the doors for medical pharmaceuticals and medical therapy.”

But the most practical outcome of the transmutation process may also be the most controversial. Most of the energy released during the transmutation of waste process – equivalent to 10 billion barrels of oil – can be harnessed to generate large amounts of electricity. What’s more, the electricity produced could not only be sold to offset the costs of transmutation, but would also provide a relatively benign energy source.
“We simply cannot sustain ourselves on fossil fuels for much longer,” says Hechanova. “Just look at what it’s doing to the environment. Transmutation is one of the best possible solutions to this problem because it shows how we can maximize nuclear energy by getting the most out of the material we already have. And it won’t contribute whatsoever to the global warming problem because it doesn’t produce any of the greenhouse gases.”

Still, not everyone considers nuclear transmutation to be a good thing. One of the biggest arguments against the technology is that it will make radioactive materials more accessible to terrorists. And although Hechanova and Beller both concede that the proliferation risk would initially be higher during the chemical separation of the plutonium from used fuel (by a process similar to that used to obtain plutonium for weapons), they say the risk decreases significantly once the plutonium is eliminated in a transmutation reactor. In addition, new proliferation-resistant separation processes are being developed. “Ultimately, transmutation could eliminate the proliferation risk because the weapons-grade material will simply no longer exist,” says Hechanova.

Hechanova says he respects the opinions of nuclear power opponents, but thinks there is a widespread lack of understanding when it comes to the realities of nuclear energy.

“What a lot of people don’t realize is that the nuclear industry is probably the most regulated, the most scrutinized, and the safest industry you will ever see,” he says. “Actuarially, nuclear power has caused fewer deaths than hydropower and fossil fuel power.”

Regardless of the statistics, Hechanova knows that some people just find all things nuclear morally reprehensible. “There are anti-nuclear people out there who just want all nuclear processes to shut down – they want to close Pandora’s box. For them, transmutation solves a problem that they don’t want to have solved because it could completely spark a renaissance in the nuclear industry.”

But a lot has to happen before a renaissance can occur. Since the Carter administration, U.S. policy has prohibited the recycling of used nuclear fuel. As a result, the country has accumulated a large amount of nuclear waste, which, without a change in policy, will need to be buried in deep, geologic repositories.

Estimates show that, by the time the operational period of current nuclear reactors is over, the U.S. will need to store approximately 185,000 tons of spent nuclear fuel – more than the capacity of Yucca Mountain. And this past June, the U.S. Senate passed a controversial bill that will, among other things, subsidize the construction of six new nuclear power plants – the first new plants to be ordered in this country since the accident at the Three Mile Island reactor in 1979.

Hechanova believes that to manage the amount of used fuel these plants will generate, the United States will have to build multiple deep geologic repositories or invest in transmutation technologies, the latter of which could do away with the need for even one Yucca Mountain.

Even with the considerable technical and political challenges ahead, Hechanova is confident about the future of the program. Plans are already under way to expand facilities on campus. These plans include construction of a thermal hydraulics laboratory, which will be used to examine a variety of science and engineering phenomena, such as the corrosion and strength of materials used during the transmutation process.
Most recently the program announced plans to build a new actinide chemistry lab in which students can conduct research on how elements such as uranium, plutonium, neptunium, and americium will respond in waste repositories, in the environment, and in nuclear recycling systems and power plants.

At the same time, the TRP is expanding its research tasks. Four new tasks will be added, as will new faculty members in the areas of nuclear physics, molten metal coolant technology, and reactor physics. Hechanova also hopes to build complementary academic programs in radiochemistry, material science and engineering, and nuclear engineering.

“At the rate we’re going, UNLV will soon be among the most respected nuclear research institutions in the country,” says Hechanova. “Our students are playing a critical role in putting the U.S. back at the forefront of nuclear science and technology. Their future in this field is as bright as they want it to be.”