Radionuclide sorption on well construction materials

Laboratory experiments were conducted to measure the extent to which trace concentrations of radioactive materials would sorb on well construction materials and to assess the rapidity with which sorption would occur. The radionuclides employed in these studies were tritium, Cs-137, and Co-57. Solutions with trace concentrations of these radionuclides were contacted with casings of PVC, fiber-glass-epoxy, stainless steel, carbon steel, and steel rods coated with epoxy. The PVC showed no interaction with the tritium or Cs-137 during contact times of two hours to three weeks; however, it did sorb Co-57. The fiber-glass-epoxy also interacted only with the cobalt. The stainless steel sorbed cesium and cobalt. The epoxy-coated steel rods did not interact measurably with any of the radionuclides so long as the coating was intact. The sorption reactions generally were apparent after a few days of contact; in the case of carbon steel, they were detectable in a few hours