FGR 13 and K-40 -Reply

[Charles Willis <CAW@nrc.gov>]

Chris,

With all the squabbles we had about FGR-13, I do not remember the answer to this
one.  A possibility is the unique situation of K-40.  That is, the concentration of
K-40 in K is nearly constant and the concentration of K in humans is relatively
insensitive to the intake of K.  Thus, the models used for the other nuclides would
be inappropriate for K-40.  If you want the right answer, try asking Keith Eckerman
or Rich Leggett at ORNL or Chris Nelson at EPA.

Charlie Willis
caw@nrc.gov