This report contains the results from the initial stage of the Hanford Waste VitrificationProject (HWVP) CompositionVariabilityStudy (CVS). This initial stage of the study was conducted in 1989 and 1990, and is referred to as CVS-I. This report is a cleared-for-publication version of the May 1991 internal project report which originallydocumentedthe CVS-I results. Because this is essentiallya May 1991 report being published in January 1993, some discussions,terminology,and referencesmay not be current due to developmentsduring the intervening19 months. Further, the results themselveshave been supersededby results from the second stage of the study (CVS-II). The purpose in publishingthe report at this time is to provide a publicly referencableaccount of the CVS-I study, because of its importancein laying the foundationfor CVS-II.