This document describes the process controls for the tank 241-U-107 (U-107) saltcake dissolution proof-of-concept operations. Saltcake dissolution is defined as a method by which water-soluble salts will be retrieved from the Hanford Site radioactive waste tanks utilizing dissolution as the mobilizing mechanism. The proof-of-concept operations will monitor the retrieval process and transfer at least 100 kgal of fluid from tank U-107 to the double-shell tank (DST) system during the performance period. Tank U-107 has been identified as posing the highest long-term risk to the Columbia River of all single shell tanks (SSTs). This is because of the high content of mobile, long-lived radionuclides mostly in the saltcake waste in the tank. To meet current contractual and consent decree commitments, tank U-107 is being prepared for interim stabilization in August 2001. It is currently scheduled for saltcake retrieval in 2023, near the end of the SST retrieval campaign because of a lack of infrastructure in U-Farm. The proof-of-concept test will install a system to dissolve and retrieve a portion of the saltcake as part of, and operating in parallel with, the standard interim stabilization system to be installed on tank U-107. This proof-of-concept should provide key information on spray nozzle selection and effective spray patterns, leak detection, monitoring, and mitigation (LDMM) and in-tank saltcake solubility data that will help in the design of a full-tank retrieval demonstration system.

Results of column dissolution experiments designed to evaluate the physical and chemical processes inherent to saltcake dissolution are presented along with model chemical equilibrium calculations. Two different compositions representing saltcakes in Hanford tanks were characterized, and porosities and permeabilities for a third composition based upon the saltcake waste in Tank 41H at the Savannah River Site (SRS) were also evaluated. Whereas the surrogates are all chemically similar, the presence of high phosphate loadings for the Hanford (HNF) simulants was noted as significantly affecting draining. The permeability was higher for the SRS saltcake, and the sodium nitrate loading in this saltcake was roughly 80% by weight compared to less than 60% by weight for the HNF compositions. Average values of the permeability and porosity were reduced for the surrogates based on Hanford Tanks S-112 and S-101. Here a secondary layer formed above the saltcake bed and was found to contain a large amount of gibbsite, Al(OH)3. Experiments with 3 molal (m) NaOH as a diluent, compared to water, did not result in additional layer formation that has been attributed to a change in local pH thereby altering the solid liquid equilibrium. Chemical analysis of the two HNF saltcakes indicated solids re-precipitation as a function of diluent added. The events were signified by large decreases in the nitrate and carbonate anion concentrations and were confined to low % dilution by weight values. Solids re-precipitation is noted as arising from the mixing of the dissolved saltcake stream with pockets of saturated interstitial liquor.

This document presents the results of the salt cake dissolution proof-of-concept retrieval demonstration conducted in tank 241-U-107. A water distribution system was operated in conjunction with the interim stabilization saltwell pumping equipment to retrieve and remove additional waste from the tank.

This document provides the test preparation and conduct of a cesium removal test using Hanford Single Shell Tank Saltcake from tanks 241-BY-110, 241-U-108, 241 U 109, 241-A-101, and 241-S-102 in a benchscale column. The cesium sorbent to be tested is crystalline silicotitanate.

Disposal of radioactive waste from nuclear weapons production and power generation has caused public outcry and political consternation. Nuclear Wastes presents a critical review of some waste management and disposal alternatives to the current national policy of direct disposal of light water reactor spent fuel. The book offers clearcut conclusions for what the nation should do today and what solutions should be explored for tomorrow. The committee examines the currently used "once-through" fuel cycle versus different alternatives of separations and transmutation technology systems, by which hazardous radionuclides are converted to nuclides that are either stable or radioactive with short half-lives. The volume provides detailed findings and conclusions about the status and feasibility of plutonium extraction and more advanced separations technologies, as well as three principal transmutation concepts for commercial reactor spent fuel. The book discusses nuclear proliferation; the U.S. nuclear regulatory structure; issues of health, safety and transportation; the proposed sale of electrical energy as a means of paying for the transmutation system; and other key issues.

On cover: Reclamation, Managing Water in the West. Describes how transformers work, how they are maintained, and how to test and evaluate their condition.