[en] Two on-site management options for handling the NFS high-level waste were analyzed: in-tank cement solidification and perpetual tank storage of the liquid waste. The cost of converting the 8D4 plus 8D2 waste to a cementitious solid, including mixing, grout preparation, and transfer to tank 8D1 would require $3,651,000; the cost of cooling the solidified solid for 15 years, plus the cost of filling the rest of the tank space and annulus with grout, plus the cost of minimum surveillance are $10,002,000. Modification of tank 8D2 would be required; prior to transfer of the waste, tank 8D1 would also be modified for cooling of the grout mass. Estimated costs of perpetual tank storage (replacing the existing neutralized waste tank after 10 years, then transferring contents at 50-y intervals for 1000 y, with replacement of ventilation system and auxiliaries at 30-y intervals) would require a sinking fund of $11,039,000. The acidic 8D4 waste would be transferred at 50-y intervals. The sinking fund requirements are sensitive to the difference between the interest rate and the escalation rate, and also to the time assumed from present to the first tank replacement