CH-TRAMPAC - Waste Isolation Pilot Plant - U.S. Department of ...

CH-TRAMPAC Document Rev. 2, May 2005testing methodology of the UFGTP. This methodology is consistent with that used in thedetermination of dose-dependent G values in Appendix 3.3 of the CH-TRU PayloadAppendices. 1Site implementation of the UFGTP long-term objective must be documented in site-specificprograms approved by DOE-CBFO.5.2.5.5.1 Required Data and Criteria for SubpopulationContainers that are identified by process knowledge or other characterization to have similarproperties with respect to gas generation are grouped into populations. The basis for groupingindividual containers into a population shall be documented (e.g., by item description codesshowing all containers are generated from the same waste stream). Within a given population, asubpopulation size may be determined and subjected to gas generation testing (i.e., measurementor container gas generation testing). The results of testing the subpopulation may be used tocalculate flammable gas generation properties for the remainder of the population. Thefollowing data for each container of the subpopulation (i.e., that has undergone gas generationtesting or measurement) shall be available:• Content code and shipping category, from which the maximum allowable FGGR isdetermined• Date of container closure, date of venting, and date of measurement or testing• Methane concentration (Section 5.2.5.3.1)• Flammable gas generation rate (Section 5.2.5.3.4 or 5.2.5.4)• Total gas generation rate for Waste Type IV (Section 5.2.5.4).5.2.5.5.2 Statistics for Required Subpopulation SizeContainers selected for evaluation (i.e., the subpopulation) must be representative of thepopulation with random or stratified sampling techniques used to avoid any bias in containerselection. The required subpopulation size to implement the long-term objective will becalculated through the following equation 5 :where,n 0nNn =1+n0( n −1)0N= A conservative subpopulation size for an infinite population for a confidencelevel of 95% and a ±5% precision level. In this case, the upper tail of thedistribution curve is of interest, and n 0 has a value of 271. 5= The required subpopulation size= The true population size.As shown by the formula, the minimum number of required containers depends on the truepopulation size.5.2-46