AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT

The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar into Tank 50. Saltstone samples were prepared with an 'MCU' type salt solution spiked with ammonia. The ammonia released from the saltstone was captured and analyzed. The ammonia concentration found in the headspace of samples maintained at 95 C and 1 atm was, to 95% confidence, less than or equal to 3.9 mg/L. Tank 50 is fed by several influent streams. The salt solution from Tank 50 is pumped to the salt feed tank (SFT) in the Saltstone Production Facility (SPF). The premix materials cement, slag and fly ash are blended together prior to transfer to the grout mixer. The premix is fed to the grout mixer in the SPF and the salt solution is incorporated into the premix in the grout mixer, yielding saltstone slurry. The saltstone slurry drops into a hopper and then is pumped to the vault. The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar{reg_sign} L into Tank 50. Waste Solidification-Engineering requested that the Savannah River National Laboratory (SRNL) perform testing to characterize the release of ammonia in curing saltstone at 95 C. The test temperature represents the maximum allowable temperature in the Saltstone Disposal Facility (SDF). Ammonia may be present in the salt solution and premix materials, or may be produced by chemical reactions when the premix and salt solution are combined. A final report (SRNS-STI-2008-00120, Rev. 0) will be issued that will cover in more depth the information presented in this report

CLOSURE OF HLW TANKS PHASE 2 FULL SCALE COOLING COILS GROUT FILL DEMONSTATIONS

This report documents the Savannah River National Laboratory (SRNL) support for the Tank Closure and Technology Development (TCTD) group's strategy for closing high level radioactive waste (HLW) tanks at the Savannah River Site (SRS). Specifically, this task addresses the ability to successfully fill intact cooling coils, presently within the HLW tanks, with grout that satisfies the fresh and cured grout requirements [1] under simulated field conditions. The overall task was divided into two phases. The first phase was the development of a grout formulation that satisfies the processing requirements for filling the HLW tank cooling coils [5]. The second phase of the task, which is documented in this report, was the filling of full scale cooling coils under simulated field conditions using the grout formulation developed in the first phase. SRS Type I tank cooling coil assembly design drawings and pressure drop calculations were provided by the Liquid Waste (LW) customer to be used as the basis for configuring the test assemblies. The current concept for closing tanks equipped with internal cooling coils is to pump grout into the coils to inhibit pathways for infiltrating water. Access to the cooling coil assemblies is through the existing supply/return manifold headers located on top of the Type I tanks. The objectives for the second phase of the testing, as stated in the Task Technical and Quality Assurance plan (TTQAP) [2], were to: (1) Perform a demonstration test to assess cooling coil grout performance in simulated field conditions, and (2) Measure relevant properties of samples prepared under simulated field conditions. SRNL led the actual work of designing, fabricating and filling two full-scale cooling coil assemblies which were performed at Clemson Engineering Technologies Laboratory (CETL) using the South Carolina University Research and Education Foundation (SCUREF) program. A statement of work (SOW) was issued to CETL [6] to perform this work

ISOPAR L RELEASE RATES FROM SALTSTONE USING SIMULATED SALT SOLUTIONS

The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Decontaminated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour, the Isopar{reg_sign} L in the vault headspace is well mixed, and each pour displaces an equivalent volume of headspace, the maximum concentration of Isopar{reg_sign} L in the DSS to assure 25% of the lower flammable limit is not exceeded has been determined to be about 4 ppm. The amount allowed would be higher if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the amount of Isopar{reg_sign} L released versus time can be treated as a percentage of initial amount present; there was no statistically significant dependence of the release rate on the initial concentration. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release rate is larger than at lower temperatures. Initial curing temperature was found to be very important as slight variations during the first few hours or days had a significant effect on the amount of Isopar{reg_sign} L released. Short scoping tests at 95 C with solvent containing all components (Isopar{reg_sign} L, suppressor trioctylamine (TOA), and modifier Cs-7SB) except the BOBCalixC6 extractant released less Isopar{reg_sign} L than the tests run with Isopar{reg_sign} L/TOA. Based on these scoping tests, the Isopar{reg_sign} L releases reported herein are conservative. Isopar{reg_sign} L release was studied for a two-month period and average cumulative release rates were determined from three sets of tests each at 95 and 75 C and at ambient conditions. The overall average releases at were estimated for each temperature. For the 95 and 75 C data, at a 5% significance level, the hypothesis that the three test sets at each temperature had the same average percent release can be rejected, suggesting that there was a statistically significant difference among the three averages seen in the three experimental tests conducted. An upper confidence limit on the mean percent release required incorporation of variation from two sources: test-to-test variation as well as the variation within a test. An analysis of variance that relies on a random effects model was used to estimate the two variance components. The test-to-test variance and the within test (or residual) variance were both calculated. There is no indication of a statistically significant linear correlation between the percent Isopar{reg_sign} L release and the Isopar{reg_sign} L initial concentration. From the analysis of variance, upper confidence limits at confidences of 80-95% were calculated for the data at 95 and 75 C. The mean Isopar{reg_sign} L percent releases were 67.33% and 13.17% at 95 and 75 C, respectively

DIRECT DISPOSAL OF A RADIOACTIVE ORGANIC WASTE IN A CEMENTITIOUS WASTE FORM

The disposition of {sup 137}Cs-containing tetraphenylborate (TPB) waste at the Savannah River Site (SRS) by immobilization in the cementitious waste form, or grout called ''saltstone'' was proposed as a straightforward, cost-effective method for disposal. Tests were performed to determine benzene release due to TPB decomposition in saltstone at several initial TPB concentrations and temperatures. The benzene release rates for simulants and radioactive samples were generally comparable at the same conditions. Saltstone monoliths with only the top surface exposed to air at 25 and 55 C at any tetraphenylborate concentration or at any temperature with 30 mg/L TPB gave insignificant releases of benzene. At higher TPB concentrations and 75 and 95 C, the benzene release could result in exceeding the Lower Flammable Limit in the saltstone vaults

Effects of Particulate Air Pollution on Cardiovascular Health: A Population Health Risk Assessment

Particulate matter (PM) air pollution is increasingly recognized as an important and modifiable risk factor for adverse health outcomes including cardiovascular disease (CVD). However, there are still gaps regarding large population risk assessment. Results from the nationwide Behavioral Risk Factor Surveillance System (BRFSS) were used along with air quality monitoring measurements to implement a systematic evaluation of PM-related CVD risks at the national and regional scales. CVD status and individual-level risk factors were collected from more than 500,000 BRFSS respondents across 2,231 contiguous U.S. counties for 2007 and 2009. Chronic exposures to PM pollutants were estimated with spatial modeling from measurement data. CVD outcomes attributable to PM pollutants were assessed by mixed-effects logistic regression and latent class regression (LCR), with adjustment for multicausality. There were positive associations between CVD and PM after accounting for competing risk factors: the multivariable-adjusted odds for the multiplicity of CVD outcomes increased by 1.32 (95% confidence interval: 1.23–1.43) and 1.15 (1.07–1.22) times per 10 µg/m3 increase in PM2.5 and PM10 respectively in the LCR analyses. After controlling for spatial confounding, there were moderate estimated effects of PM exposure on multiple cardiovascular manifestations. These results suggest that chronic exposures to ambient particulates are important environmental risk factors for cardiovascular morbidity

MEASUREMENT OF AMMONIA RELEASE FROM SALTSTONE

SRNL was requested by WSRC Waste Solidification Engineering to characterize the release of ammonia from saltstone curing at 95 C by performing experimental testing. These tests were performed with an MCU-type Tank 50H salt simulant containing 0, 50, and 200 mg/L ammonia. The testing program showed that above saltstone made from the 200 mg/L ammonia simulant, the vapor space ammonia concentration was about 2.7 mg/L vapor at 95 C. An upper 95% confidence value for this concentration was found to be 3.9 mg/L. Testing also showed that ammonia was chemically generated from curing saltstone at 95 C; the amount of ammonia generated was estimated to be equivalent to 121 mg/L additional ammonia in the salt solution feed. Even with chemical generation, the ammonia release from saltstone was found to be lower than its release from salt solution only with 200 mg/L ammonia

Hitting the distributed computing sweet spot with TSpaces

Our world is becoming increasingly heterogeneous, decentralized and distributed, but the software that is supposed to work in this world, usually, is not. TSpaces is a communication package whose purpose is to alleviate the problems of hooking together disparate distributed systems. TSpaces is a global communication middleware component that incorporates database features, such as transactions, persistent data, ¯exible queries and XML support. TSpaces is an excellent tool for building distributed applications, since it provides an asynchronous and anonymous link between multiple clients or services. The communication link provided by TSpaces gives application builders the advantage of ignoring some of the harder aspects of multi-client synchronization, such as tracking names (and addresses) of all active clients, communication line status, and conversation status. For many di€erent types of applications, the loose synchronization provided by TSpaces works extremely well. This paper relates our experiences in building distribute