The Reactor...it glows so BLUE!

On October 11, about a dozen Physics Society members took a tour of the nuclear reactor located behind the Materials Research Laboratory (MRL). It was given by Mark Kaczor, a reactor health physicist. He first gave a talk on radiation and radioactive isotopes, nuclear reactors, and nuclear safety. Then we got a full tour of the facilities, including seeing the reactor pulse. For 15 milliseconds, the reactor had a power output approximately one-third that of the typical output of a nuclear power plant like Clinton. At the instant of the pulse, a flash could be seen, and an erie blue glow was left behind -- Cherenkov radiation from electrons travelling in water faster than the speed of light.

Did you know...?

• The greatest risk of radiation exposure for most people is from radon gas. Radon is part of the uranium decay sequence, and in regions of higher uranium deposits close to the Earth's surface, radon percolates its way up and can collect in basements and tightly-insulated homes.
• Radiation is a natural part of our environment. Among food items, salad oil is actually very high in radioactive components.
• Much of the danger from cigarette smoking is due to radioactive isotopes in fertilizers that make their way into the tobacco and then into lungs, where they decay and produce radiation.
• German beer contains more radioactive isotopes than American beer. Says Mark Kaczor, "because there's nothing in American beer." :-)
• Possibly the biggest obstacle to interplanetary space travel is radiation poisoning. In order to protect astronauts from the onslaught of cosmic and solar radiation, a prohibitively large amount of heavy shielding would have to be lifted into orbit.
• The shuttle flies "upside-down" not to give astronauts a good view of the big blue marble but to keep the bulk of the orbiter's mass between them and radiation as a shield.
• This nuclear reactor is not used to produce electricity. Rather, the neutrons which are a "by product" in electrical power generation are harnessed in medical and other experiments. By exposing certain substances to neutron radiation, some become radioactive and are then used in scientific studies. Often the isotopes produced have short half-lives.
• Alpha particles cannot penetrate the skin, but if radioactive isotopes enter the body and emit the particles inside, they can do serious damage to cells. Most of the outer skin cells are dead already, and something as thin as a sheet of paper is enough to block alpha particles.
• Food items are often exposed to radiation sources to preserve the food -- the radiation kills the bacteria, and the food is not then radioactive.

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