MU research reactor churns out neutrons, nanoparticles

Jennifer Lu/ 1 min ago

The MU Research Reactor emits its characteristic blue glow. (photo courtesy of the MU Research Reactor Center)

The MU Research Reactor emits a characteristic blue glow. (photo courtesy of the MU Research Reactor Center)

A nuclear operator stands straddled across the platform of the MU Research Reactor. Wearing gloves for protection, he rotates a long metal pole that extends into the blue glowing depths of the water-filled reactor tank.

Attached to the pole is a batch of samples being irradiated inside the reactor. The operator repositions the samples so that every batch receives an even dose of radiation. The reactor irradiates materials for medical, commercial, and research purposes, such as radioactive gold and trace metals, for clients on campus, in Columbia, and across the nation.

At 10 megawatts, the research reactor at MU is the largest such reactor in the country. It runs on a process called fission, which releases the atomic energy packed inside the centers of uranium atoms.

The reaction starts with a few small particles called neutrons, which are found in the nuclei of atoms. When a neutron hits a uranium atom just right, the atom temporarily absorbs, or gains, an extra neutron. This addition destabilizes the atom so that it splits into two smaller elements. This fragmentation also releases energy and more neutrons, which go on to bombard other uranium atoms, like a self-perpetuating chain of falling dominoes.

Nuclear power plants use the liberated energy to heat water, make steam, and turn turbines to generate electricity.

At the MU reactor, however, the water reaches a mere 136 degrees Fahrenheit.

That’s hardly hot enough to do laundry, MU research reactor director Ken Brooks quipped during a tour of the facility in January as part of a journalism workshop.

Instead, the researchers care about generating a steady flow of neutrons. The MU research reactor is capable of generating up to 60 trillion neutrons per second per square centimeter inside the reactor, according to the MURR website.

Brooks calls it a “neutron oven.”

Using these neutrons, the MU research reactor can make dozens of radioactive elements. Researchers do this by exposing canisters filled with samples to the neutrons inside the reactor.

Kattish Katti, professor of radiology and physics, designs prostate cancer-targeting nanoparticles from radioactive gold produced at the reactor. With a diameter approximately 10,000 times smaller than human hair, these nanoparticles can maneuver into the smallest of crannies in the body.

To avoid healthy tissue, Katti coats the nanoparticles with special molecules derived from cinnamon or mango skins that bind to cancer cells. As the gold nanoparticles decay, they emit radiation in the form of beta particles that penetrate and destroy malignant cells.

Meanwhile, Jeffrey Ferguson, an assistant professor in the archaeometry laboratory, uses the reactor to study the migration and trading patterns of peoples long ago.

Shards of pottery can be analyzed with neutrons to create a distinct emission profile that corresponds to the exact composition of the clay, which differs from region to region. Another technique determines the origins of volcanic glasses like obsidian rock.

While most of these samples come from artifacts such as spears and knives, Ferguson was most enchanted with a pebble no larger than his thumbnail that seemed to have no discernible function.

The rock was discovered in New Mexico, but tests showed that someone had brought it from Arizona.

Ferguson liked to think that the pebble held some sentimental value.

Perhaps it was a souvenir, he said.

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