Monday, July 13, 2015

Nuclear Reactor

Lately Jasper has become deeply fascinated with radiation and nuclear power. It was obviously time to get an inside look at the Reed Reactor, a nuclear research reactor at Reed College in Portland. They offer amazing free tours, and will give students wonderful labs as well. Jasper thought this was the most mind bogglingly spectacular thing ever! The kids got to try their detection lab, where they placed a tablecloth over a ton of random objects and set the kids free with geiger counters to find the ones that were radioactive. Then they revealed what was underneath. The most radioactive item? Antique red Fiestaware! Prior to WW2, uranium was used fairly commonly as a pigment in glass and pottery glaze. That all came to a halt when the US government decided it had other uses for uranium. But radioactive elements continued to be used for such items as glow in the dark clock faces, exit signs and smoke detectors. They also carefully explained what radioactivity is and what apha, beta and gamma radiation are. (Alpha radiation emits protons and neutrons, beta radiation emits electrons, and gamma radiation is pure energy.)

After the lab, we were given a complete tour of the reactor itself and their control room. The deadly seriousness of the safety protocol surrounding the operation of a nuclear reactor is offset by some quite silly industry terms. The Nuclear Regulatory Agency designates that when the reactor is being operated, one person must be the official "Reactor Operator" and a second person must be on hand as the official "Warm Body", wearing the corresponding name tags.  They also have an emergency shutdown procedure, known as the "SCRAM", which is officially signaled when a reactor worker mimes chopping with an axe. Legend has it that the first nuclear reactor had a control rod dangling above it on a rope, and the rope was to be cut by axe in case of emergency so the rod would drop into the reactor. SCRAM was said to stand for "safety control rod axe man", a marvelous bit of foolishness. The kids got to give the axe chopping signal to initiate a demo of the shutdown, to their vast amusement. 

Why Reed College?  Reed Chemistry Professor Arthur F. Scott, who eventually became the College President, was very interested in radiochemistry and was instrumental in having the Reed Research Reactor built in 1968.  There are 31 research reactors nationwide, but this one is the only one at a liberal arts school and the only one operated mainly by undergraduates. (There is actually another one in Oregon, at OSU in Corvallis.)  I imagine that this must make Reed uniquely attractive to anyone interested in this field who would love to work with a research reactor without having to wait until graduate school. Research reactors have limited scope, and their safety features prevent them from ever allowing their reactors to generate enough heat to boil their water.  So they do not create steam as power generating reactors do.  The Reed Reactor is used to irradiate samples, which are then placed in a gamma ray spectrometer, a very precise instrument for detecting their atomic composition. Recent studies have been used to determine the precise composition of ancient Mediterranean pottery, revealing the exact location the clay was taken from. If the pottery was found far from its source, trade routes can be discovered. Samples can be retrieved from the reactor with a specialized tool which costs thousands of dollars, but at Reed they found that a fishing pole gets the job done just as well.

The reactor sits in highly purified water, with only hydrogen and oxygen atoms and no dissolved minerals. Our guide explained that neither kind of atom can become radioactive, and the water serves as a shield. Because it is so pure, it appears quite blue. They turned the lights out so that we could also see the "blue glow" coming from the reactor. This is not actually the reactor itself glowing, but a strange effect of radioactive particles passing through water. The speed of light traveling through water is slightly slower than the speed of light in, say, the vacuum of space. The blue glow is caused by radioactive particles exceeding the normal speed of light in water. They do not allow photography in the Reed Reactor, except for photos directly into the reactor. But hey, that's the coolest thing to see!

Nuclear power- very scary and very, very bad, right? Well... I certainly used to think so! I remember Three Mile Island, Chernobyl and of course Fukushima with horror. I've been outraged to hear nuclear energy touted as "green energy". But since Jasper has taken an interest in this topic, we've learned that green energy generated by sources such as wind and solar cannot yet be stored, so the world is unable to meet our energy needs with these two sources alone. In Germany, public opinion turned radically against nuclear power following the accident in Japan, and they are now on a course to burn through a lot of coal, which is an environmental disaster.  We just don't yet have the perfect energy solution in place.  Since about 2/3 of the energy we generate is wasted because it's transmitted inefficiently, we can go way further towards meeting our energy needs just by being more efficient. But right now is not a great time to close down existing plants. I mentioned this quandary about phasing out nuclear power and having to resort to coal, and found our student guide well versed on the subject.  Worldwide, 4,000 times more deaths have been caused by coal per unit of power generated than nuclear power, millions of deaths versus about 5,000.  And the majority of deaths from nuclear accidents were in Chernobyl, a disaster caused by an inferior safety protocol which has since been banned worldwide.  Definitely food for thought.

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