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Unstable N-16

  1. Oct 22, 2007 #1
    Can anyone help me to understand the function of nitrogen in PWR.

    What I know about unstable N-16 is that it is used as an indication of power PWR. How fast does it achieve an equilibrium activity?

  2. jcsd
  3. Oct 22, 2007 #2


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    Staff: Mentor

    The half-life of N-16 (which is produced by an n,p reaction of O-16) is 7.16 s, so equilibrium is achieved rapidly - in about 1 minute. But then it also decays quite rapidly, so a detector must be close to the core. It's activity would be a function of the fast flux, which itself is related to the rate of fission or power.

    N-16 is a matter for BWRs, which use hydrogen (reducing) water chemistry, since N-16 is carried through the main steam line to the turbine. PWRs use a slightly reducing water chemistry to prevent crud transport, although the pH these days tends to be 6.9 - 7.4 depending on the plant.

    http://www.nndc.bnl.gov/chart/reCenter.jsp?z=7&n=9 (then use zoom 1 in upper right corner)
  4. Oct 25, 2007 #3
    Thnx 4 yo speedy & what I find as an accurate answer to the question. Many more thanx for providing the link. Cheers!
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