Category Archives: Basics

General topics providing background in nuclear science and engineering.

Nuclear Plant Siting and Earthquake Risk

In the wake of the Fukushima crisis, there has been much discussion of how to site future nuclear plants in locations that are relatively less vulnerable to earthquakes. Although we offer no opinions or recommendations on this issue, we will … Continue reading

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Fission Products and Radiation

When a heavy atom (such as uranium or plutonium) undergoes fission, it splits into two lighter fission products. This splitting process also yields two or three neutrons, which can cause other heavy atoms to fission, as well as a huge … Continue reading

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What is criticality?

The words “criticality” and “re-criticality” have been used extensively in the media coverage.  Criticality is a nuclear term that refers to the balance of neutrons in the system. “Subcritical” refers to a system where the loss rate of neutrons is … Continue reading

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What is an isotope?

It seems that there is a lot of confusion as to what isotopes, radioisotopes, nuclides, and radionuclides are.  First, we have to go back to chemistry class and remember the periodic table of elements, which lists all of the chemical … Continue reading

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A Summary on Plutonium in Nuclear Fuel

Mixed Oxide (MOX) Fuel Uranium occurs naturally on earth. We mine it, refine it, and use it as fuel in nuclear reactors. All other elements that can sustain the nuclear fission chain reaction, including plutonium, do not occur naturally on … Continue reading

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What is Decay Heat?

Explanation of Nuclear Reactor Decay Heat Nuclear reactors produce electricity in a similar way to conventional coal plants in that they heat steam to drive a turbine that spins an electric generator.  However, they differ on how that heat is … Continue reading

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What are Spent Fuel Pools?

Spent nuclear fuel pools Spent nuclear fuel (SNF) refers to fuel after it has fueled a reactor.  This fuel looks like new fuel in the sense that it is made of solid pellets contained in fuel rods.  The only difference … Continue reading

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