steam drillers, page-12

The water in the aquifer, being already hot for millions of years, will be in equilibrium with any soluble radionuclides in the granites. As the water is recirculating I would not expect any increase.

I have come across the same problem in oil wells. What we found was that the radionuclides do collect in pipe scale if that forms but as a general rule do not induce radioactivity in the steel itself. If you can stop scale formation then there is no radiation buildup. If you dont though disposal of the scale after cleaning does present a problem.

Neil