Dr. Rajesh Maingi
» Subsections: PPPL
Senior Research Scientist, Oak Ridge National Laboratory, Princeton Plasma Physics Laboratory
Dr. Rajesh Maingi , April 17, 2006
Rajesh Maingi is a senior research scientist at the Princeton Plasma Physics Laboratory based in Princeton, NJ, United States. He went to North Carolina state university and obtained a degree in Nuclear Engineering. He went on to graduate work at NCU on nuclear fusion obtaining a Ph.D, travelling to Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and Oak Ridge National Laboratory. He graduated in 1992 with a Ph.D. in nuclear engineering and took a Department of Energy job at Oak Ridge National Laboratory.
He has conducted experiments on fusion devices at the Massachusetts Institute of Technology (MIT), San Diego, in Germany, and in England. His day-to-day activities including running fusion experiments over several machines.
On April 17, 2006, members of our team interviewed Mr. Maingi at the Princeton Plasma Physics Laboratory (PPPL). He gave us a generous tour of the facility, including the NSTX Control Room and the site where the reactor itself is housed.
Audio Excerpts
Dr. Maingi on:
Personal Biographical Information
How He Got Started in Nuclear Physics
"In 12th grade we had to do a senior project in physics class and I chose to do one on nuclear fusion... and that got me interested in the topic to begin with"
His Job at Oak Ridge National Laboratory / PPPL
"My job is a research scientist... Essentially its conducting nuclear fusion research on a variety of machines..." - listen
"...you learn a little bit about things and then you would change something...there are a lot of variables that one can change in order to affect the performance of the plasma itself... magnetic field... electric current... density... shape" - listen
Danger of a Nuclear Fusion Power Plant
"...In fact, its very difficult to do anything wrong with a fusion power plant...You actually don't have more than just a few minutes worth of fuel in the plasma... If the plasma grows in a way that you weren't expecting it... that material comes in and that material can cause such rapid radiation and energy loss that it quenches the reaction rather quickly. In some sense a plasma is a self-regulating system. That's essentially why we make the statement that it really can't blow up... You can't have a meltdown at the level you had a Three Mile Island... It's inherently much safer... It's also the reason why its much harder.. " - listen
"When you have the prospect of creating nuclear energy, you have the prospect, the capability of creating bombs..." - listen
"...There's another issue of how you keep the byproducts safe. This is the downside of nuclear energy, that you create radioactive byproducts. The advantage of fusion is that you have byproducts that are around for decades instead of thousands of years with fission..." - listen
Is there any risk that the research you're doing here will be used for weapons? "I don't think so. No. I mean, most of the basics, that kind of stuff, is known. What we're trying to do is keep it controlled for the periods of time that we need to generate energy output..." - listen
Security at PPPL
"...There really is no research here that is confidential...The main thing that they worry about is, particularly after September 11, is not people are going to try to steal secrets but people who are going to mistake that this is a high security and confidential facility...If it's a terrorist, they might attack it on the mistaken assumption that there is something that's...radioactively explosive or nuclear explosive here." - listen
Nuclear Weapons
"...getting the materials, that's the hard part. Also, getting the technology for making detonators, that's the hard part... What the world does is they try to keep a very tight control on the material itself... Most nuclear physicists would know the simple technology that's involved..." - listen
"So essentially what you do there is you don't care about controlling it... you get the temperature so hot in some manner that it essentially fuses together and then it explodes outwards and creates an enormous amount of energy." - listen
"The prospect...would be similar, except there's no need for critical mass kinds of issues with fusion. With fission, you do have to have a critical mass of the stuff." - listen
"This is deuterium fusing with tritium. If you have enough of it, it can grow uncontrollably just like fission reactions can grown uncontrollably." - listen
Heavy Water
"...Heavy water is essentially when you have water as H20. If you take the hydrogren out and you replace the hydtogen with a deuterium..that is the beginning of what you need to create bomb-like materials" - listen
Deuterium-Tritium Fusion Reaction
"This reaction that you see-deuterium plus tritium-is the easiest reaction to get energy multiplication out of... the first thing you have to do is to trip the electrons off of them to make a plasma...once you get it above 10 or 11 million degrees kelvin you end up stripping the electrons anyway...there's a natural repulsive force between the two which is actually quite strong..." - listen
"...This helium nucleus has about 3 million electron volts and [the neutron] has about 15 million electron volts... It only takes a fraction of the percent of the mass converted to energy under Einstein's relation to yield so much energy...the energy multiplication can be as high as 450 to 1..." - listen
Fission Reaction
"In fission reactions, there are two kinds of neutrons that come out. There are prompt neutrons that come out as the process of the fission reaction itself and there are delayed neutrons that come out hundreds of milliseconds later. If you get the reaction with enough fissile material with enough enrichment, you don't need the delayed neutrons and then the energy can grow exponentially in a matter of hundreds of microseconds..." - listen
"The key with fission is there is something that is known as a critical mass... If you have enough fissile material and you put it together and its a critical mass, then essentially all you need is a single neutron that comes in or a cosmic ray or some energy source that comes in that starts a chain reaction and the reaction will grow uncontrollably."
History
Tokamak Fusion Test Reactor (TFTR)
"The cartel got their act together and was really successful at controlling the amount of gas that was sent around the world. There was a large increase in fusion research, that was in the '76-'77 timeframe..." - listen
Description of TFTR Test Vacuum Vessel
"..This is the piece of TFTR that they used as practice for the decommissioning. Because they put tritium in TFTR and it became radioactive, they wanted to practice to make sure that they could minimize the spread of tritium when they were decommissioning it..." - listen
National Spherical Torus Experiment (NSTX)
"Back in the mid-90's... we had all kinds of problems with our deficit and our debt... all kinds of research went down... fusion was one of the groups that got hard hit. The message that we got from DOE and the administration, mostly Congress... was that 'we think you're doing interesting research, but the project you're projecting is too expensive...'" - listen
Description of the NSTX Control Room - listen
Nuclear Fusion Energy Reactors
Vacuum Vessel
"...What you have is you're looking at the outside of the vacuum vessel... the containment unit... if you stripped it all away, then you have a basic vacuum vessel and the plasma is inside that vacuum vessel..." - listen
Neutral Beams and other heating mechanisms
"...The prospect of heating something up to 100 million Kelvin-If you have to conceive of how you would do it... How would you do it?"
Cost of Research
"The annual operating budget of NSTX is about $30 million... Each day is worth half a million dollars." - listen
Tritium
Tritium is radioactive and has a certain halflife, so then you have to run decontamination procedures... ne of the Obig advantages over fission is that you do create radioactive materials with fusion but they don't stay around as long, not like thousands of years in fission power plants." - listen [tritium.mp3]
Continually Fueling a Fusion Reactor
"You continually fuel it with several different ways..." - listen
The Future
ITER
"The goal is to create a reactor based on what we've learned in the last 50 years of fusion research... that is scheduled to be built by 2016... We'll learn enough from that that we'll be able to make a demonstration reactor... something in the range of 50 years from now. At the earliest, maybe 35 years..." - listen
Nuclear Energy in the Future
"There is a reasonably high degree of confidence that something that looks like ITER will produce net amounts of power...that it'll work..." - listen
"...With nucelar power, its going to be an important element in our future. Its hard to get around that... By and large, I think we can overcome those hurdles - the safety hurdles." - listen
For Future Nuclear Physicists
"Make sure that you get as much math and physics as you can. Math is critical in trying to understand what we do here... Physics, you have to make sure to take..." - listen
"You have to more or less go to graduate school if you want to become on the scientific staff..." - listen
- Maingi, Rajesh. Princeton Plasma Physics Laboratory. Personal Interview. 17 Apr. 2006. To view our notes of the interview, click here.
