Closure report for underground storage tanks 321-I1U1, 321-I1U2, and 321-I1U3 and associated underground piping

摘要

Underground storage tanks (USTs) 321-IlUl, 321-IlU2, and 321-IlU3, located in the Building 321 area at Lawrence Livermore National Laboratory (LLNL) (Fig. A-1 and A-2, Appendix A), were registered with the State Water Resources Control Board as USTs 321A-11X,321A-12X,and 321A-13X and were subsequently renamed. This tank system consisted of three polyvinyl chloride (PVC) lined concrete sumps and approximately 400 ft of underground 4 in. PVC piping (Fig. A-2, Appendix A). Sumps 321-IlUl and 321-IlU3 each had a capacity of 3,000 gal, and tank 321-IlU2 had a capacity of 3,700 gal. These sumps were constructed in 1974 and were used to receive waste rinsewater containing acids, metals, and possibly some organic solvents from the plating shop operations at Building 322. Sump 321-IlU3 received the rinsewater from Building 322. Sump 321-I1U2 received the acidic backwash, and sump 321-IlUl received the caustic backwash from the ion-exchange columns. The sumps remained in service until January 1986. In 1988, the sumps were cleaned and decontaminated in preparation for closure.