This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. vii ABSTRACTThe Savannah River Site (SRS) has been evaluating technologies for removing radioactive cesium ("'Cs) from the supemate solutions stored in the high-level waste tanks at the site. Crystalline silicotitanate (CST) sorbent (IONSIV IE-9118, UOP LLC, Des Plaines, IL), which is very effective at removing cesium from high-salt solutions, was one of three technologies that were tested. Because of the extremely high inventory of 137Cs expected for the large columns of CST that would be used for treating the SRS supemate, any loss of flow or cooling to the columns could result in high temperatures from radiolytic heating. Also, even under normal operating conditions, the CST would be exposed to the supernates for up to a year before being removed. Small-scale batch and column tests conducted last year using samples of production batches of CST showed potential problems with CST clumping and loss of cesium capacity after extended contact with the simulant solutions. Similar tests-using samples of a baseline and improved granular CST and the CST powder used to make both granular samples-were performed this year to compare the performance of the improved CST. PThe column tests, which used recirculating supemate simulant, showed that the baseline CST generated more precipitates of sodium aluminosilicate than the improved CST. The precipitates were particularly evident in the tubing that carried the simulant solution to and fi-om the column, but the baseline CST also showed higher concentrations of aluminum on the CST than were observed for the improved CST. Recirculating the simulant through just a section of the tubing (no contact with CST) also produced small amounts of precipitate, similar to the amounts seen for the improved CST column. The sodium aluminosilicate formed bridges between the CST granules, causing clumps of CST to form in the column. Clumps were visible in the baseline CST column after 1 month of operation and in the improved CST column after 2 months, For the baseline CST column, the clumps were routinely dispersed by backwashing the column with simulant. After 96 days of operation, a thin hard layer of CST formed on the bottom screen of the baseline column that restricted flow through the column. The bottom cap was removed and the CST was scraped from the screen to restore the...

The Savannah River Site (SRS) is evaluating technologies for removing cesium-137 (137Cs)horn the supemate solutions stored in the high-level waste tanks at the site. Crystalline .&licotitanate sorbent (IONSIV IE-9 11', UOP Molecular SievesYMt. Laurel, NJ) is very effective for removing cesium from high-salt solution, such as the SRS supemates, and is currently being used at Oak Ridge National Laboratory to remove radioactive cesium from similar solutions. Because of the extremely high loading of 137CS that would be expected for the large columns of crystalline silicotitanate (C ST) that would be used for treating the SRS supemate, any loss of flow or cooling to the columns could result in high temperatures within the column from radiolytic heating. The ability of CST to retain previously loaded cesium while in contact with SRS tank supernates at various temperatures was determined by performing bench scale simulant tests using CST samples that were loaded with stable cesium and radioactive cesium tracer. These results were compared with those obtained fi-om loading tests at the same temperatures.. .

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a b s t r a c tAs a result of increased concerns regarding public safety in recent years, the impact and penetration resistance of infrastructure has become an emerging research focus in the cement and concrete industry. Ultra-high performance concretes (UHPCs) with fiber reinforcement usually possess compressive strengths greater than 200 MPa and are promising candidates for penetration-resistant building materials. In the current project, two UHPC materials, ERDC-M (a modified composition developed at U.S. Army Engineer Research and Development Center) and Ductal Ò , were subjected to projectile penetration testing. The microstructural evolution due to projectile impact and penetration was examined via scanning electron microscopy and X-ray diffraction. Possible phase changes were observed in the affected material volume, which can be interpreted as resulting from the high temperature and high pressure induced by the impact and penetration.

The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants.An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures. iv v