Dow uses reactor for research

Published March 19, 2002 in the Midland (MI) Daily News

Beth Medley Bellor

What’s it like staring into a nuclear reactor?

Kind of peaceful. The lights make the water a light blue that looks as if there should be fish swimming in it. Way down at the bottom are 78 fuel rods that will go to work in a minute and when that happens, the resulting glow also will be blue — not green like on “The Simpsons,” the nearby scientists grouse. They’re not terribly fond of the way the TV show portrays nuclear science, it seems.

The scene is The Dow Chemical Co.’s nuclear research reactor. Yes, the company has one; no, we’re not going to tell you which building it’s in. Suffice it to say three people look up when you step in the front door.

It’s a rarity. Only a few dozen such reactors are in the United States, none at other chemical companies, which offers Dow a considerable competitive advantage when testing new products.

The TRIGA nuclear reactor — Testing Research Isotope production, General Atomics — produces a maximum of 300 thermal kilowatts of power, tiny by power plant standards.

“We don’t use it for electricity, we use it for research,” said Ward Rigot, reactor supervisor. He holds degrees in chemistry and nuclear engineering and has been in charge of the reactor for two decades.

“We put 9,500 experiments through the reactor last year,” he said. “It’s another tool in our tool chest for providing information for our researchers.”

The work is called neutron activation analysis. The technology has been around since 1936, even before reactors. “It’s a very mature science, very well understood,” Rigot said.

Analysis allows Dow to check chemical and physical properties of matter, for example, testing for trace impurities down to parts per billion. The reactor irradiates samples, and calculations and charting are done in a nearby room.

Standing in that room pointing at a graph on a screen, Rigot said, “This is where we actually do the majority of the benefit for the customer.”

Employees who want work done fill out a TRIGA activation request form. With a reactor in house, sometimes the turnaround is as little as a day.

“The thing I like about it most is we see so many parts of The Dow Chemical Co.,” Rigot said. “I can name every business we have at Dow and we support that business.”

That ranges from “old school” materials such as plastics to cutting-edge research such as SiLK semiconductor dielectric resins and polymer light emitting diode technologies, both of which have exacting standards for purity.

Dow even is involved in pharmaceutical testing, but for atomic particles called ligands, not radioactivity. “It’s somewhat counterintuitive,” Rigot admitted.

A November article in Science magazine mentioned work on a “smart bomb,” but not the kind you might think. Dow helped characterize a ligand for cancer research.

“It’s one of those quantum steps you see in research. We’re happy with the small part we played in that,” he said.

The reactor is sometimes known as a swimming pool-type reactor. It is a light water reactor, as opposed to one using heavy water.

It is 21 feet deep and 6 1/2 feet across, sunk into the ground. Including the plastic-lined grate that covers it, a few controls and the “fission pole” — a $4,000 isotope lifting assembly that looks like it could yank steelhead out of a river — the whole deal easily could fit in the average garage.

The core is 19 inches high and 22 inches across. The outer ring is a carbon ring which reflects neutrons back into the core and minimizes the amount of energy needed.

The core temperature reaches only about 480 degrees. The water temperature is about 86 degrees. It can’t exceed 140 degrees, but that’s not for safety — it’s because ion exchange resins break down beyond that.

Water is the coolant and the primary shielding. Standing by the reactor during a short demonstration, Rigot said the radiation level was 10 millirem per hour, “Which means I could only stand here for 500 hours a year before I got my maximum exposure.”

He wears a special quarter-sized tag that will beep if levels get dangerously high, but he doesn’t worry. “People in other parts of the country who are exposed to more background radiation probably get more than I do.”

Those would be people who live at higher elevations, or in areas with high radon concentrations. While he is allowed 5,000 millirem a year exposure because of his occupation, the Dow standard is the same as for the general public — 500. He has accumulated 400 over his lifetime, he said.

The vast majority of the isotopes they deal with have half-lives of less than one minute. Indeed, shortly after the demonstration reaction, the blue glow fades, much like a TV screen fading.
The reactor’s redundant controls include both computers and hard wiring to monitor power, temperature and other levels. When it is not operating, it is in shutdown mode.

A story noting the reactor’s startup was published in the Midland Daily News on Aug. 10, 1967.

“This is the last time we were on the front page of the Midland Daily News, and I view this as a good thing,” Rigot said.

In 1989, the reactor was relicensed for another 20 years. The mayor’s office gets copies of all the Nuclear Regulatory Commission’s reports.

The facility was upgraded around 1990 and is inspected about once a year. There are internal audits and peer review audits, lasting several days. The reactor’s four licensed reactor operators continually requalify; one of them has worked there since 1969.

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