This temperature is what is known as closure temperature and represents the temperature below which the mineral is a closed system to isotopes. The bottom two entries, uranium and thorium, are replenished as the long-lived uranium atoms decay.
If the flood were global in scope, radiocarbon dating is why then would we have any rocks for which a number of different methods all agree with each other?
Furthermore, astronomical data show that radioactive half-lives in elements in stars billions of light years away is the same as presently measured.
He does not see a conflict between science in its ideal form the study of God's handiwork and the Bible, or between miracles on the one hand, and an old Earth on the other. There is absolutely no evidence to support this assumption, and a great deal of evidence that electromagnetic radiation does not affect the rate of decay of terrestrial radioactive elements.
These atomic clocks slow down very slightly only a second or so per year as predicted by Einstein's theory of relativity.