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6 March 2014 1:04 pm ,
Vol. 343 ,
Magdalena Koziol, a former postdoc at Yale University, was the victim of scientific sabotage. Now, she is suing the...
Antiretroviral drugs can protect people from becoming infected by HIV. But so-called pre-exposure prophylaxis, or PrEP...
Two studies show that eating a diet low in protein and high in carbohydrates is linked to a longer, healthier life, and...
Considered an icon of conservation science, researchers at World Wildlife Fund (WWF) headquarters in Washington, D.C.,...
The new atlas, which shows the distribution of important trace metals and other substances, is the first product of...
Early in April, the first of a fleet of environmental monitoring satellites will lift off from Europe's spaceport in...
Since 2000, U.S. government health research agencies have spent almost $1 billion on an effort to churn out thousands...
- 6 March 2014 1:04 pm , Vol. 343 , #6175
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Quake Question #10: Why Are Spent Rods So Deadly?
18 March 2011 2:11 pm
Readers ask: Does the life of the rods affect their radioactive capabilities? Like, if they were getting near the end of their effective life, are they more or less dangerous? Are the rods the only danger, or are there other components, like cooling tanks or hydrogen containers, that are also dangerous with radioactive meltdown? Once the reactor's control rods are between sections of fuel rods, how is fission slowed to where it is controllable? It seems the control rods aren't adequate to regain control of the fission.
Science answers: Spent fuel is more dangerous because it contains a mixture of fission products, some of which can be long-lived radioactive waste, and also plutonium which is highly toxic.
In a boiling water reactor like those at Fukushima, the same water that cools the reactor core also boils and drives the turbine to generate power. This means that some radioactive material gets into the turbine and condensers and pumps, but these are usually very short-lived radionuclides.
When the control rods are inserted into the core, they absorb neutrons and stop the fission chain reaction. But they do not stop spontaneous fissions in fuel rods from fuel and fission products. These spontaneous fissions are what keep the fuel rods hot even when the core is shut down.