Sometimes other signs and symptoms precede sudden cardiac arrest. These may include fatigue, fainting, blackouts, dizziness, chest pain, shortness of breath, weakness, palpitations or vomiting. But sudden cardiac arrest often occurs with no warning.
In the core of nuclear reactors, the fission of uranium atoms releases energy that heats water to about 520 degrees Farenheit. This hot water is then used to spin turbines that are connected to generators, producing electricity.
They constitute a real-time control of the fission process, which is crucial for both keeping the fission chain reaction active and preventing it from accelerating beyond control. The nuclear fission chain reaction is the fundamental process by which nuclear reactors produce usable energy. Most commonly, Uranium U-235 is the fissionable material used in this chain reaction (as shown in Fig.