Test Plan: Sludge Treatment Project Corrosion Process Chemistry Follow-on Testing

Abstract

ForwardThis test plan was prepared by the Pacific Northwest National Laboratory (PNNL) under contract with Fluor Hanford (FH). The test plan describes the scope and conditions to be used to perform laboratoryscale testing of the Sludge Treatment Project (STP) hydrothermal treatment of K Basin sludge.On July 3, 2007, the U. S. Department of Energy (DOE) provided direction (a) to FH regarding significant changes to the scope of the overall Sludge Treatment Project. As a result of the changes, FH directed PNNL to stop work on most of the planned activities covered in this test plan. Therefore, it is unlikely the testing described here will be performed. However, to preserve the test strategy and details developed to date, the test plan has been published.Prior to the changes in project direction, a final version of the test plan was issued for review. Consistent with the request of the DOE, Dr. J. Abrefah (PNNL) provided an independent technical review (Appendix C), and most of his comments have been incorporated into this document (Appendix E). FH also provided technical review (Appendix D) and these comments have been addressed (Appendix E). As a result of the project redirection, comments from other stakeholders (DOE, US Environmental Protection Agency, and BNG America) were not prepared. Much of the testing in this plan will be conducted in a sequential manner that allows the knowledge obtained in one series to refine the next series of tests. Thus, the initial tests will be static tests designed to duplicate the previous experiments and to benchmark the behavior of sludge at the current lower design processing temperature for the STP. Testing with a broader set of sludge compositions will follow to improve the understanding of the chemistry producing high shear strength values. Testing will also be performed using a scaled (1-L) reactor to evaluate the effects of mixing, with the agitation level set to match that anticipated in the STP corrosion vessel.The planned testing is designed to yield further understanding of the nature of the chemical reactions, the effects of compositional and process variations and the effectiveness of various strategies to mitigate the observed high shear strength phenomenon observed by Delegard et al. (2007). These tests are being conducted to provide process validation and refinement vs. process development and design input. The expected outcome is to establish a level of understanding of the chemistry such that successful operating strategies and parameters can be implemented within the confines of the existing STP corrosion vessel design. K Basin Sludge OverviewThe sludge currently found in the water-filled Hanford K Basins is a mixture of particulate materials including irradiated metallic uranium reactor fuel, fuel corrosion products, wind borne soil, filter sand, corrosion products from racks (iron and aluminum), canisters (aluminum), and walls (concrete), spilled organic and inorganic Ion Exchange Module (IXM) media (mixed bed cation/anion resin and mordenite), and other ...

Preparation and Characterization of Uranium Oxides in Support of the K Basin Sludge Treatment Project

“…Uraninite and metaschoepite were to serve as feed material for further hydrothermal treatment tests that had been planned in accordance with Sludge Treatment Project (STP) corrosion process chemistry follow-on testing (Delegard et al 2007b). Although most of the planned hydrothermal testing was cancelled in July 2007 (as described in the forward of Delegard et al 2007b), uranium oxide procurement and lab tests on the preparation of metaschoepite by reaction of uraninite with oxygen, reaction of hydrogen with metaschoepite, and characterization of the various starting, product, and intermediate materials were continued to improve the understanding of uranium oxide chemistry in sludge and to provide well-characterized uranium oxides suited to support evolving STP initiatives (Sloughter 2007). Testing with well characterized uranium oxide provides better experimental control and is significantly less costly that equivalent testing with the highly radioactive genuine sludge.…”