How to use scramed in a sentence? Find typical usage patterns (collocations)/phrases/context for "scramed" and check conjugation/comparative form for "scramed". Mastering all the usages of "scramed" from sentence examples published by news publications.
The reactor had vertical fuel channels, in contrast with the normal CANDU arrangement where the tubes are horizontal. The reactor did not use conventional control rods, but relied on control of the level of the heavy water moderator to adjust the power output. The reactor could be shut down quickly (SCRAMed) by the rapid dumping of the moderator. In 1971 AECL initiated design engineering of a 500 MWe CANDU-OCR, based on uranium carbide fuel.
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Decay heat accidents are where the heat generated by the radioactive decay causes harm. In a large nuclear reactor, a loss of coolant accident can damage the core: for example, at Three Mile Island a recently shutdown (SCRAMed) PWR reactor was left for a length of time without cooling water. As a result, the nuclear fuel was damaged, and the core partially melted. The removal of the decay heat is a significant reactor safety concern, especially shortly after shutdown.
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Most neutrons in a reactor are prompt neutrons; that is, neutrons produced directly by a fission reaction. These neutrons move at a high velocity, so they are likely to escape into the moderator before being captured. On average, it takes about 13 μs for the neutrons to be slowed by the moderator enough to facilitate a sustained reaction, which allows the insertion of neutron absorbers to affect the reactor quickly. As a result, once the reactor has been SCRAMed, the reactor power will drop significantly almost instantaneously.
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For a reactor that is SCRAMed after holding a constant power level for an extended period (greater than 100 hrs), about 7% of the steady- state power will remain after initial shutdown due to fission product decay. For a reactor that has not had a constant power history, the exact percentage is determined by the concentrations and half-lives of the individual fission products in the core at the time of the SCRAM. The power produced by decay heat decreases as the fission products decay.
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Decay heat as fraction of full power for a reactor SCRAMed from full power at time 0, using two different correlations When a nuclear reactor has been shut down and the nuclear fission chain reaction has ceased, a significant amount of heat will still be produced in the fuel due to the beta decay of fission products. For this reason, at the moment of reactor shutdown, decay heat will be about 7% of the previous core power if the reactor has had a long and steady power history. About 1 hour after shutdown, the decay heat will be about 1.5% of the previous core power. After a day, the decay heat falls to 0.4%, and after a week it will be 0.2%.
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Decay heat as fraction of full power for a reactor SCRAMed from full power at time 0, using two different correlations In a typical nuclear fission reaction, 187 MeV of energy are released instantaneously in the form of kinetic energy from the fission products, kinetic energy from the fission neutrons, instantaneous gamma rays, or gamma rays from the capture of neutrons.DOE fundamentals handbook - Nuclear physics and reactor theory - volume 1 of 2, module 1, page 61 An additional 23 MeV of energy are released at some time after fission from the beta decay of fission products. About 10 MeV of the energy released from the beta decay of fission products is in the form of neutrinos, and since neutrinos are very weakly interacting, this 10 MeV of energy will not be deposited in the reactor core. This results in 13 MeV (6.5% of the total fission energy) being deposited in the reactor core from delayed beta decay of fission products, at some time after any given fission reaction has occurred. In a steady state, this heat from delayed fission product beta decay contributes 6.5% of the normal reactor heat output.
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