| Abstrak/Abstract |
For solving the radioactive waste storage problem, there is an idea to store immobilized waste at deep sea. Solidifier material, such as cement should be resistance to saline environment for deep sea storage. So, this research objective is to study the performance of cementation method in immobilizing strontium waste in saline environment. Research was conducted by immobilizing strontium waste using Portland pozzolanic cement, white cement and composite Portland cement. Cement, 65 ppm Sr(NO3)2, sand and water were mixed and cast. Strontium waste varied in 2 v/o, 4 v/o, 6 v/o and 8 v/o. After 28 days curing, the cement block’s compressive strength and leaching rate on saline water were ana- lyzed. Determination of compressive strength was done by using Universal Wood Testing. The density of blocks was measuredbypicnometerat25?C.CompressivestrengthtestforPortlandpozzolaniccementatvariousw/cwas conducted to confirm the effect of w/c in increasing the strength. For testing strontium leaching rate in water containing35 ppm NaCl, cement blocks have been immersed in saline water for 21 days. 25 ml samples were taken and analyzed by Atomic Absorption Spectrophotometer. Strontium leaching rate on block containing pH 9 of waste was compared to the previous research data of strontium leaching rate on water to know the effect of saline water. To adjust the pH, 1 M NaOH was added into the waste. Effects of various cement type and filler materials (sand, zeolite and baryte) on Portland pozzolanic cement were also compared. The results show that there were almost no effects of salt on im- mobilized strontium waste, except in pH 9 waste (0.00224 over to 0.000199 g/cm2•days). Strontium leaching rates on all cemented waste still meet the IAEA’s standard, so the safety of cemented strontium waste disposal at saline environment could be ensured |
