Effects of closure cap liner on contaminant release rates from grouted wastes

Conference · Fri Nov 01 04:00:00 EST 1996

OSTI ID:391260

Yu, A D; Fowler, J R; Bignell, D T ^[1]

---

1. Westinghouse Savannah River Company, Aiken, SC (United States)

This paper describes a groundwater modeling study of waste disposal concepts using grouted waste forms. The focus of the study is on the effects of clay claps and concrete vaults on contaminant migration. The authors modeled three waste disposal scenarios: (1) Grouted waste was solidified in an earthen trench and covered with soil. There was no vault and no cap. (2) Grouted waste was solidified in an earthen trench. The entire waste disposal facility was then closed under clay cap. (3) Grouted waste was solidified in a concrete vault and protected by the same closure as in 2. Because of the huge contrast in hydraulic conductivities and highly non-linear multi-phase flow characteristics, these waste disposal concepts presented a difficult problem for numerical simulation. Advanced fluid flow and contaminant transport codes were used to solve the problem. Among the codes tested, ECLIPSE out-performed other codes in speed, accuracy (smaller material balance errors) and capability in handling sophisticated scenarios. The focus of this study is on groundwater protection. The authors assessed the performance of three unsaturated zone waste disposal concepts. Since unsaturated zone performance relied almost entirely on the properties of the waste form, the liner and the closure, these predictions are generic. For a site-specific performance assessment (PA) and design of waste disposal facility, the authors need to factor in (1) inventory, (2) alternative liners such as polymer and geotextile membranes, (3) degradation histories of waste form, liner and closure, (4) hydrogeological conditions, and (5) cost.

• OSTI ID: 391260
• Report Number(s): CONF-960482--
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
CLAYS
CLOSURES
GROUND DISPOSAL
GROUND WATER
GROUTING
LINERS
LOW-LEVEL RADIOACTIVE WASTES
MATHEMATICAL MODELS
RADIONUCLIDE MIGRATION