A study to determine the economical tank size for radioactive waste disposal

Abstract

Purpose of this report is to determine optimum tank size from evaluating the quantities of principal construction materials with prevailing unit costs for various tank sizes. The materials were concrete in-place, reinforcing steel in-place, wood framework, 3/8 in. C steel plate liner in-place, earthwork excavation and backfill (engineering, overhead, piping, condenser, vapor manifold costs not included). Costs of optimum tank are distributed as follows: dome 25%, walls 28%, foundation 6%, floor 2%, steel liner 20%, earthwork 19%. For a given tank capacity, there is a definite optimum tank size; as the capacity increases, the diameter increases, and the height increases but at a lesser rate. Each diameter has an optimum height, which is that height at which unit cost of storage space is minimum for a given tank diameter. Optimum unit cost is $0.136/gallons for diameters 75--130 ft; for diameters<75 ft, the optimum unit increases. Tank forms 241-S, 241-SX, and 241-A were used in this study; storage cost of the analyzed tank was $0.121 compared to $0.136/gallon for 241-SX and 241-A, and $0.152/gallon for 241-S. Assumed unit costs for concrete and steel plate tank liner were 10% less than those of 241-SX and 241-A, causing the lower unit costs. Tanksmore » used for 241-SX and 241-A are close to optimum tank size. Although a small savings in storage unit cost will result from optimum dimensions, greater savings could be realized by increasing the tank capacity 20--25% without changing tank diameter or storage unit cost. Curves in the appendix can be used to select optimum tanks for new tank farms.« less