A Researcher’s Perspective on the Situation in Japan

by Michael Mullaney on March 15, 2011

 

The nuclear engineering community at Rensselaer is quickly trying to assess the ongoing nuclear crisis in Japan. We’ve been in touch with many faculty and students in the Department of Mechanical, Aerospace, and Nuclear Engineering, to get some insight.

Peter Caracappa, a nuclear engineer and the radiation safety officer at Rensselaer, has been quoted by several news outlets. Caracappa says that even though Japan faces a “beyond worst case” disaster, a Chernobyl-level scenario is still not possible:

“The Chernobyl accident spread radioactive material over a large area due to a massive fire of graphite in the reactor, whereas the reactor in Japan does not use graphite in the core.”

He told Popular Mechanics that even though the Japanese and Ukranian facilities both date from the early 1970s, the Japanese plant at Fukushima was a much safer design. Here’s a bit from the story:

For starters, the Fukushima facilities use water to both cool its reactors and moderate its nuclear reaction speeds. The Chernobyl facility also used water to cool its reactors, but used volatile graphite to slow its reactions to produce heat. When Chernobyl’s Reactor No. 4 exploded, this graphite caught fire and burned like coal, billowing radioactive material across Europe. “In Fukushima, the fuel will melt, but it is surrounded by water and won’t burn nearly the same way as graphite,” says Peter Caracappa, a Radiation Safety Officer and assistant professor at Rensselaer Polytechnic Institute, who has studied the power systems of plants like Fukushima.

Professor Yaron Danon spoke with channels 9, 10, and 13 yesterday and over the weekend about the dynamic situation in Japan. In one of the interviews, he says:

“I want to emphasize that an additional safety mechanism – the containment of the reactor even after the explosion of unit one - should still be in tact. So even if there is partial or full meltdown of the core, which might be possible if they lose the cooling, radioactivity will not be released from these sites.”


The Rensselaer student chapter of the American Nuclear Society (ANS) say they’re receiving up-to-date information from the national ANS. The professional society is reporting that even the most seriously damaged of Japan’s 54 reactors have not released radiation at levels that would harm the public. This is a testament to the nuclear engineering philosophy of defense in-depth, excellent designs, high standards of construction, conduct of operations, and most important the effectiveness of employees in following emergency preparedness planning, the student group says.

Sastry Sreepada, a clinical professor of nuclear engineering at Rensselaer, taught a course last fall on nuclear reactor probabilistic risk assessment. He says nuclear power plants are typically designed for natural disasters such as earthquakes, but not to one of unprecedented size. He spoke to the Daily Gazette in Schenectady yesterday. Here’s a short clip from the story:

“[Sreepada] acknowledged the damaged Japanese plants were designed to withstand earthquake and tsunami, but said Friday’s tsunami wave was higher than what the plant’s tsunami wall was designed to handle.

The plant operators’ response, he said, “went by the book, but the book did not anticipate Richter 9.”

Rian Bahran, a doctoral candidate at Rensselaer in Nuclear Engineering and Science was a student in Sreepada’s class. Rian says much of the nuclear-related research performed at Rensselaer has implications to reactor safety. The experimental nuclear data research conducted at the Rensselaer linear accelerator lab (LINAC) by graduate students like Rian under the supervision of Professor Yaron Danon ultimately allows researchers to accurately design nuclear reactors within specific safety margins. Computational methods developed by Professor Wei Ji and his graduate students also help researchers perform faster calculations for both the design and assessment of different reactors. Professor George Xu’s research on methods for measuring radiation in the environment and Professor Jie Lian’s nuclear materials research also helps contribute to this culture of safety.

Here’s what Rian says:

The current generation of nuclear engineering students across the nation were either not alive or barely remember the events at Chernobyl in Russia or Three Mile Island in Penssylvania. We have never witnessed a crisis like this firsthand. We learn about the commitment and application of redundant levels of safety in nuclear reactor operation in textbooks and in our classes, but to hear about many of these safety components failing one-by-one, without specific details or a full grasp on what the final implications – the human cost – is very difficult.

Rian was quoted a few years ago in this nice AP story on the growing demand for nuclear engineering. He notes that he is working with the Rensselaer student chapter of ANS and its executive board to help organize a public open forum discussion on the Japan nuclear crisis as soon as students return from spring break next week. He says the student chapter and its members have become the de facto experts amongst their family and friends, and are ardently trying to obtain and provide up-to-date, technically sound information in order keep the public debate factual and quell people’s concerns.

Please check back in the coming days, as we’ll continue to keep a close eye on Japan. Our thoughts and best wishes go out to everyone who has been impacted by the tragic earthquake and tsunami.