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06 September 2008

Answer to Question #6232 Submitted to "Ask the Experts"

Category: Nuclear Power — Nuclear Energy

The following question was answered by an expert in the appropriate field:

In what application would a QF (quality factor) of 20 for fission fragments be used in power plant health physics?

NOTE: 10 CFR 20 assigns a QF of 20 to fission fragments.

Fission fragments are the new atoms that are formed when the fissionable atoms of uranium and plutonium in the reactor fuel are split apart. When formed, these fragments are energetic, fast-moving particles that can ionize atoms, but they travel only a very short distance in matter. Since nuclear fission occurs inside of the fuel rods which are inside a reactor containment vessel and since fission fragments travel a very short distance in matter, no person is exposed to energetic fission fragment particles from fissions of fuel atoms at a nuclear power plant.

The purpose of the quality factor (QF) for fission fragments is for calculating the biological dose for fission fragments emitted inside the human body from fissionable atoms that are somehow taken into the body by ingestion, inhalation, or injection. Such an exposure to people is unlikely at a nuclear power plant where the fissionable material is encased within the fuel rods which are inside the reactor containment vessel.

Otto G. Raabe, PhD, CHP

Answer posted on 26 March 2007. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.