Case Studies: Full-Scale Operations and Delivery Systems - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 336

13.4.3.5 QC and Results ............................................................... 358
13.4.4 Case Study #4: Radioactive Waste Stabilization at the
U.S. Department of Energy Savannah River Site ......................... 358
13.4.4.1 Background and Purpose ................................................ 358
13.4.4.2 Saltstone Facility............................................................. 359
13.4.4.3 High-Level Waste (HLW) Tank Fill ............................... 361
References.............................................................................................................. 363

13.1 INTRODUCTION

The ultimate goal of all of the science, technology, and laboratory testing involved in
S/S is the successful treatment of actual hazardous, radioactive, or mixed wastes. To
accomplish this goal, two tasks must be carried out: (1) the optimum chemistry
determined in testing must be scaled-up to the applicable field conditions, and (2) a
physical/mechanical system — a “delivery system” — must be chosen to meet the
demands of treating the waste and complying with the site and project requirements.
The prime consideration in scale-up of S/S technology to full-scale operation is
that no two waste treatment scenarios are identical. No full-scale operation should
be planned, let alone put into practice, without the proper characterization, laboratory
testing (i.e., treatability studies), site investigation, and regulatory evaluation having
previously been conducted. These considerations are discussed in the other chapters.
Often, S/S contractors by-pass these vital requirements by relying on past experience
combined with overkill in respect to the addition of binders and additives. This
appeared to work in the past when applied to simple solidification of easy-to-treat
wastes, substituting the excess cost of chemicals for the costs associated with a
proper feasibility study. This approach is much less successful today, where more
stringent physical and chemical properties of the treated waste product are required.
The handling, storage, transportation, and disposal costs of the product are often
much higher than the actual S/S processing costs, especially in the case of radioactive
and mixed wastes. Thus, as the environmental requirements become more stringent,
the “more is better” approach often doesn't work and adds to these downstream
costs for the extra mass and volume that result.
The four case studies in this chapter are presented to give a fairly broad view
of full-scale operations with cement-based systems. Before discussing the case-by-
case specifics, the chemical scale-up and delivery systems are discussed, to provide
the reader with some background in the components of the full-scale system and to
avoid the necessity for repetition of that information in the actual case histories.

13.2 CHEMICAL SCALE-UP

Laboratory development of the appropriate S/S treatment chemistry, its dependence
on waste characteristics, the physical and chemical properties of the stabilized/solid-
ified waste forms, and test methods are discussed elsewhere in this topic. However,
what works in the laboratory doesn't always work at larger scale, a reality that has
resulted in some costly failures. Failures of this sort are usually the result of two