Tank Riser Pit Decontamination System (Pit Viper) Return on Investment and Break-Even Analysis

Abstract

This study assessed the cost benefit of Pit Viper deployment for 80 tank farm pit entries required to be cleaned out and decontaminated between October 1, 2003 and September 30, 2012 under the technical baseline in place in FY 2002 for applicable double-shell tank (DST) and singleshell tank (SST) projects. After this assessment had been completed, the U.S. Department of Energy (DOE) Richland Operations Office (RL) and Office of River Protection (ORP) published the Hanford Performance Management Plan (August 2003) that accelerated the schedule for SST retrievals. Then, DOE/CH2M HILL contract modification M064 (October 2002) and The Integrated Mission Acceleration Plan (March 2003) further accelerated SST retrieval and closure schedules compared with the Hanford Performance Management Plan. Twenty-six to 40 tanks must be retrieved by 2006. The result is that the schedule of SST pit entries is accelerated and the number of SST pit entries is increased relative to the number and schedules shown in this report. However, overall conclusions are still valid, provided that the work scope in the pits is not changed significantly. The radiation dose at the edge of the pits that were studied varies from 0 to 3,000 mrem/hr. The DST projects analyzed in this study with pit work suitable for the Pit Viper include W-314, Tank Farm Restoration and Safe Operation; W-211, DST Waste Retrieval Systems; and W-521, Waste Feed Delivery Systems. The Interim Stabilization Project will conduct work in pits between now and 2004, but it was qualitatively determined that the work schedule may begin too soon and be too short in duration for early Pit Viper deployment. SST retrieval projects will also include pit work that is suitable for the Pit Viper. This study estimates the Pit Viper return on investment (ROI) and the number of pits where Pit Viper deployment would break even or save money over current manual practices. The results of the analysis indicate a positive return on the federal investment for the deployment of the Pit Viper provided it is used on a sufficient number of pits. When sunk costs are not included, 70 of the 80 pits will break even with a 95% learning curve assumption. The results are sensitive to the assumptions made for labor hours to do work in the pits, the learning curve for the Pit Viper, the loss of efficiency due to weather, the shielding requirements and costs, the number of pit entries, the number of Pit Vipers required, and the radiation dose rates of pits (see Section 4). The total capital investment and development costs associated with the Pit Viper are about $2.3 million, and the savings resulting from Pit Viper deployment exceed $10.1 million, with a 95 percent learning curve if a single Pit Viper is used for 70 out of 80 pit entries. The calculated ROI is 33.5 percent. If the Pit Viper is used in fewer pits or not used on some high dose-rate pits that provide high returns, the ROI for the federal dollars spent will be less favorable. Also, a significant but smaller number of pits will exceed the break-...