At the Savannah River Site (SRS) we are currently finalizing the design for a multi-system vitrification process that will be installed in the F-Canyon Multi-Purpose Process Facility (MPPF), an existing highly shielded, remotely operated facility. Authorization to proceed beyond the preliminary design based on the recommendation of a Formal Design Review Board was requested in May of 1999.

The Savannah River Technology Center (SRTC) Process Development Group has been conducting research and developing a process to identify equipment design bases and process operating parameters since 1996. The goal of the project is to stabilize a tank of ∼11,000 liters of nitric acid solution containing valuable isotopes of americium (Am) and curium (Cm). Vitrification has been selected as the most attractive alternative for stabilization and provides the opportunity for recovery and eventual reuse of the actinides. The final glass form will be placed in interim storage awaiting a disposition by the Department of Energy. This paper presents a brief history of the stabilization program and an overview of the entire Am/Cm stabilization process. This paper also provides details of a specific processing issue related to drain tube pluggage (devitrification) that was encountered during the development of the baseline batch vitrification process, and the remedy employed to reduce the potential for further drain tube pluggage.

There have been several proposals for the mechanism by which we are able to recognize an object across a number of viewpoints. Viewpoint-dependent accounts suggest that recognition may be based on an incremental transformation (e.g., mental rotation) strategy, while a variety of viewpoint-independent mechanisms for object recognition have also been proposed. Recent research in neurobiology, based on the two cortical visual systems account, suggest that the processes of viewpoint-dependent and viewpoint-independent object recognition may rely on separate anatomical regions, and that brain lesions may leave patients with selective access to particular types of representation. Evidence from a variety of neuropsychological disorders are reviewed to support the position that viewpoint-independent object recognition depends upon the integrity of occipitotemporal structures. In addition, it is suggested that viewpoint-dependent processes (perhaps depending on occipitoparietal structures) may supplement this primary system under nonoptimal circumstances. (JINS, 1997, 3, 288–298.)