Word: nuclei
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When a nuclear reactor is running, its heat comes from the fissioning, or splitting, of the nuclei of uranium or plutonium atoms. These nuclei break apart when bombarded by neutrons, uncharged subatomic particles that are initially provided by a reactor ignition device. The shattered nuclei release energy and emit more neutrons. When uranium atoms are packed closely together, however, as they are in power-plant fuel rods, the neutrons emitted by the splitting nuclei break up other nearby nuclei. Each shattered nucleus contributes more neutrons and heat to what has now become a chain reaction, and the heat is used...
...with a broken radiator. The chain reaction promptly ceases because rising temperatures cause the fuel to expand, which increases the distances between individual atoms and makes it less likely that the neutrons emitted by one will hit the nucleus of another. But the spontaneous radioactive decay of nuclei goes on. The uncooled reactor core could eventually get hot enough to melt through its casing and the surrounding building, causing fires that loft radioactive material into the atmosphere. Under the worst circumstances, the core melts through the earth and in a "China Syndrome" reaches the underground water table and triggers...
...Berkeley team had focused its efforts on the bacterium Pseudomonas syringae, which lives on the leaves of many plants and actually promotes the formation of frost. As the temperature drops below 32 degrees F, specks of protein produced by the bacteria act as nuclei for the growth of ice crystals (see chart). Without the bacteria and their protein particles, plants can briefly sustain temperatures as low as 25 degrees F before the dew turns to frost. The solution seemed simple enough: from 2% to 5% of the bacteria in nature lack the ability to manufacture the protein. If large numbers...
...universe. It would enable physicists to probe fundamental mysteries about the origin of matter and energy and could help them achieve a long-sought goal: to weave the four known forces of nature--electromagnetism, gravity, the weak force (responsible for radioactive decay) and the strong force (which holds atomic nuclei together)--into a single, elegant, grand unified theory. Says Leon Lederman, director of the Fermi National Accelerator Laboratory (Fermilab), the high-energy physics facility near Chicago: "With the SSC, we are bound to make fantastic new discoveries...
...pellet's outer surface will be raised to 100 million degrees, causing it to vaporize explosively. Just as a rocket is pushed forward by its tail exhaust, the vaporizing surface would exert a force inward, compressing the pellet to a density 20 times that of lead and forcing the nuclei to fuse. In the fusion power plant of the future, Livermore scientists say, larger pellets will be blasted, one after another, producing successive bursts of energy...