You are here:
Effects of Aging and Decontamination Pressure on the Penetration of Radionuclides into Concrete
Citation:
Jolin, W., C. Oster, K. Hepler, M. Magnuson, AND M. Kaminski. Effects of Aging and Decontamination Pressure on the Penetration of Radionuclides into Concrete. In Proceedings, WM2018 Symposium, Phoenix, AZ, March 18 - 22, 2018. U.S. EPA Office of Research and Development, Washington, DC, 9, (2018).
Impact/Purpose:
Radionuclide penetration into concrete was investigated as function of time and pressure of an applied water spray. Depth profiles of three radionuclides into a concrete surface over the time periods of 20-24 hours, 9 days, and 90 days were found by grinding the surface. The profiles were starkly different between the radionuclides, as Eu-152 deposited close to the surface and did not penetrate further over time while the depth of Cs-137 increased with time. Such differences suggest that response time during a remediation effort is more important for Cs-137 decontamination compared to Eu-152. The depth profiles were also used to assess the water pressure that was needed to remove contamination. Static tests, where the surface was soaked in 0.5M KCl, accessed up to 80 µm into the surface, while ablation through high pressure washing removed approximately 10-20 µm of the surface. Similar grind profiles were then collected on decontaminated coupons, displaying that high pressure washing drove Sr-85 into the surface, decreasing the removal of the nuclide. As such, radionuclide specific decontamination may be required because of the varied response times and pressures effects for each radionuclide.
Description:
This study aims to understand the effect of the rapid decontamination methods of high pressure washing and washing with salt additives on the penetration of radionuclides into concrete. To this end, we first identified how penetration profiles of Cs-137, Sr-85, and Eu-152 evolve over time. These three radionuclides were chosen to span a number of important ion characteristics and serve a surrogates for commonly observed nuclides after a radiological release (Sr-85 for Sr-90, Eu-152 for other lanthanides and Am-241).[7] The depth profiles enabled us to infer the depth within the surface that each decontamination method is able to access. The depth profiles after decontamination suggested that salt additives and high pressures may cause Cs-137 and Sr-85 to penetrate further into concrete, respectively, raising concerns for final decontamination and indicating that radionuclide specific response may be required.