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Using the Sound of Nuclear Energy

Using the Sound of Nuclear Energy

A simple idea based on a high school experiment could be a warning signal ahead of a nuclear meltdown.

Using the Sound of Nuclear Energy

Tuesday, June 20, 2017 - 10:30

Jason Socrates Bardi, Editor

(Inside Science) -- Natural disasters can happen anywhere in the world at any time. According to Federal Emergency Management Agency, between 2011 and 2016 the United States alone dealt with more than 700 major natural disasters, ranging from floods and earthquakes to severe storms and wildfires that burned out of control.

For many disasters, the effects linger long afterwards. Strong winds from hurricanes and tornadoes can topple trees and demolish buildings. Snowstorms can knock out power for weeks. And wildfires rush through areas leaving only ashes in the wake.

In the wake of most natural disasters, the destruction can be cleaned up and things can get back to normal. But what happens when a natural disaster causes a domino effect that leaves behind problems for months and years afterwards?

In 2011, three nuclear reactors at the Fukushima Daiichi plant lost power and melted down following a massive, 9.0 magnitude earthquake. What steps can science take to help stop catastrophic effects from happening in the future?

However, it wasn’t the earthquake that caused the nuclear accident, but what happened right after.

The earthquake originated about 80 miles off the coast of the main part of Japan, Honshu island. It lasted less than 10 minutes but caused a ricochet effect that moved the entire country of Japan a few meters to the east. That tripped safety measures at the reactors, causing them to scram or shut down.

Steven Garrett, a professor of acoustics at Pennsylvania State University, said, “When the earthquake struck, it was the largest recorded earthquake. All of the systems of the reactor worked perfectly; it shut down and restarted. The problem was that 45 minutes later a tsunami came in.”

Because the earthquake's epicenter was under the ocean, it caused a subsequent tsunami that covered nearly 300 square miles, destroying or severely damaging more than a million buildings and claiming thousands of lives. The tsunami knocked out power to millions of homes and businesses, and it swamped the Fukushima power plant, flooding the generators that operated and the reactor’s emergency cooling systems. The reactors overheated, damaged the nuclear fuel and sparked hydrogen explosions that breached the reactor buildings.

“They had no information about what the state of the reactor was, what the flux was, what the coolant temperature was; they knew nothing because everything depended on electric,” said Garrett.

People living within 6 miles of the power plant were forced to leave their homes after the government ordered an evacuation.

“The disaster at Fukushima might have been less of a disaster had the people who were running the reactor had some information about the coolant temperature and the neutron flux,” said Garrett.

Garrett believes he may know a way to fix the problem. And it’s all based on a high-school level science experiment.

“I realized that we were building these thermo-acoustic engines that were very, very simple. For 10 years, I sold these kits to make the acoustic laser for high school students and college teachers and science fairs for 14 dollars a pop,” said Garrett.

Garrett added, “If I could disguise one of these acoustic lasers as a fuel rod, if they were in the middle of a reactor, then the neutron flux would generate heat, the heat would create sound, the sound would be able to propagate through the coolant and you could pick it up outside. Even if you lost electricity you’d still have access to the amplitude of the sound and the frequency.”

By planting the sensors inside the reactor core, the observers are guaranteed up-to-date measurements from the heart of the system itself. As the radioactive material releases heat, the sound waves produced by the engine are carried from the core by the cooling water and relayed to the observers. It’s a purely mechanical measurement system.

“The purpose of the sensor, which is a thermos-acoustic engine, is to generate sound that will propagate through the reactor so that we can tell, from the frequency, the temperature of the reactor coolant. Here in the laboratory, we’ll be measuring the temperature of the water in an aquarium which is several gallons. In the reactor, it’s 70,000 gallons of water. So, what I’m going to do, and normally this would all be sealed and have a high-pressure mixture of helium and argon gas in it, but for this demonstration I’ve actually left it open so that you can hear the sound as well as see the trace on the oscilloscope, and the frequency and the amplitude on the spectrum analyzer. So, if I just turn the heat on, I’m putting about 10 volts across the wire. And when it kicks in you see the sine [wave], it’s a subtle wave, that’s created by the thermo-acoustic device, and you can see a single spike because it’s a pure tone in the spectrum analyzer,” explained Garrett.

It sounds like a good idea, but how would he be able to see if it works? This may have started as a science project, but there aren’t any high schools in the U.S. that have a nuclear reactor to test the theory. Luckily, there is a college.

“We were fortunate in that Penn State has the first nuclear reactor that was ever put on a college campus. The reason we have it is that in the ’50s, Milton Eisenhower was the president of Penn State and Dwight was his brother. When they signed the Atoms for Peace, which was a very forward-looking piece of legislation, after Hiroshima and Nagasaki, it was a bold legislation. Penn State then got the reactor. It was very convenient. It was a seven-minute drive from my laboratory,” said Garrett

In 1953, President Dwight D. Eisenhower addressed the United Nations about the constructive use of atomic power.

“I know that the American people share my deep belief that if a danger exists in the world, it is a danger shared by all -- and equally, that if hope exists in the mind of one nation, that hope should be shared by all,” said Eisenhower.

Eisenhower believed everyone, even people outside the world of physics, should have access to the facts about nuclear power. The Atoms for Peace program supplied equipment and information to schools, hospitals, and research institutions within the U.S. and around the world.

Penn State was the first university to take advantage of this program and received the first research reactor license issued by the U.S. Atomic Energy Commission. Then in 1956, it was one of only two universities established as an international school of nuclear science and engineering.

Today, more than 3,000 visitors, ranging from elementary school students to scientists and government officials, visit the Breazeale Nuclear Reactor (at Penn State) each year to learn about nuclear technology.

Garrett has tested his device here at Penn State, and is working on more tests at bigger facilities. But what about the cost?

“The ones that went into the reactor were contained in a test tube, a stainless steel welded enclosure. There’s nothing expensive. The stack itself where the thermos-acoustics take place was a chunk of extruded ceramic that you have in your car exhaust system. I don’t see that the cost will be driven by the materials. It may be driven by certifications or changes in nuclear regulatory commission regulations,” said Garrett.

Right now, there are more than 400 nuclear reactors operating in 30 countries around the world. Fukushima is one of just three major reactor accidents in the history of civil nuclear power, along with accidents at Three Mile Island in the United States and at Chernobyl in the former Soviet Union. But safety is still a big concern.

“I think that what we should be doing is an experiment using gamma heating to convince the commercial industry that it is safe to put it into a commercial reactor. Once we do that and get it into commercial reactors the technology will become to be widespread. Everything these days depends on cooperation between commercial manufacturers,” said Garrett.

Now he’s looking to test his idea in a bigger reactor.

“We’re really looking forward to doing the same experiment in the advanced test reactor in the Idaho National Labs which has adequate gamma flux. The Penn State reactor is a megawatt reactor. The advanced test reactor is a 250-megawatt reactor. Commercial reactors are about a gigawatt,” said Garrett.

And even though finding a way to test the concept isn’t easy, avoiding another incident like Fukushima is vital. Nuclear accidents affect an area for years and possibly generations into the future. The cleanup and decommissioning of Fukushima reactors is still ongoing, several years after the disaster. TEPCO, the company that runs Fukushima, estimates a cleanup of 40 years!

It also costs millions, if not billions, of dollars to return things to normal after a natural disaster. Hurricane Katrina caused an estimated $108 billion in damage.

In addition to the visible effects on a landscape, there’s the impact natural disasters have on the people who survive them and in some cases, on people who weren’t even there when catastrophe hit.

Snow storms can trap people in their homes for days or even weeks. And new research shows a sharp spike in hospital admissions for heart trouble in the days following snow storms. Flooding can cause unsafe drinking water that can lead to illness. And in the case of Fukushima, it’s believed that the radioactive materials in the plant leaked into the ground, ran into the ocean, and were even released into the air by steam while crews were trying to cool down the reactors.

Multiple lawsuits have been filed against TEPCO and the Japanese government. In at least one case, a health ministry panel in Japan agreed that a worker, who was diagnosed with leukemia, was eligible for compensation because his illness was workplace related. He worked on the cleanup at Fukushima.

Garrett’s idea may just be what’s needed.

“I was very fortunate that Penn State had a reactor on campus because we could do the electrical experiments, but you can’t do nuclear experiments without a reactor,” concluded Garrett.

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Jason Socrates Bardi is the News Director of the American Institute of Physics and a longtime science writer.