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Report for NDEP
Report prepared for NDEP
Prussian blue (PB) nanoparticles in different form were studied for the adsorptive enrichment of Cs in solutions. Water dispersible nano-PB was found to be highly effective on removing trace level Cs in stagnant waters. The nano-PB loaded filters were effective on collecting Cs in flow systems like river water, thus provides a big relief on controlling the environmental mobility of Cs and its entry to the productive lands via water. Water insoluble nano-PB adsorbent possesses high Cs loading capacity and selectivity and it is found to be the ultimate option for the systems containing high concentration Cs. (authors)
Report prepared for NDEP
A process is proposed to reuse ion exchange resins. The process consists of ion exchange beds for the ion exchange and regeneration, regeneration solution (regenerant) make-up tanks, an evaporator for concentration of spent regenerant, a dryer for the drying of concentrate, a pulverizer for grinding dried salt and a mixer for polymer solidification of the salt. A spent resins storage tank and a spent regenerant storage tank are also involved in the process. The role of each component in the process for reuse of the resins is explained. In addition, the effect of the reuse of ion exchange resins by regeneration was estimated in view of the reduction of spent resins. As the number of regenerations increases, the volume of spent resins is obviously inversely proportional to the number of regenerations. Although a polymer waste form is generated instead of spent resins when the ion exchange resins are reused, its volume is only about one-fifth of that of spent resins. (authors)
Radiological decontamination is an essential enterprise that has become more important over the last four decades due to unfortunate accidents and the threat of terrorist actions. Decontamination can be an effective, beneficial alternative for the cleanup of radiological contamination events; however, the costs and benefits need to be balanced against those for complete removal and demolition of contaminated areas or facilities. Demolition and removal are often the first options considered in such circumstances as decontamination may be thought of as slow and costly. Decontamination has advantages, including significant waste reduction over demolition. In areas with buildings of cultural or societal importance, demolition may not be an option. Three decontamination evaluation test series are the focus of this article: SIMCON 1 and 2 (i.e., simulated contamination), and Urban RDD (radiological dispersal device, i.e., a dirty bomb detonation). These test series revealed that different contaminants respond differently during decontamination. This was found to be true with both SIMCON and Urban RDD simulant tests. SIMCON 2 especially demonstrated that chemically different contaminants respond differently to different decontamination methods: cesium appears to be less tenacious (more easily removed) than zirconium using chemical methods. These differences were underscored by the Urban RDD tests where americium and cobalt tended to precipitate on high pH surfaces (such as concrete), making them easier to remove, while cesium and strontium were essentially unaffected by surface pH and were imbibed more strongly into the substrate pore structure. While authorities argue over the contributions of contaminant chemistry and substrate morphology, the clear answer is that each has a contribution to the tenacity of a contaminant. Knowing how these characteristics interact will make us better at decontamination in the field. This knowledge refutes the efforts of perhaps well-meaning marketers to define our decontamination problems by what products they are trying to sell; often a 'one size fits all' type approach. Knowing even a little bit about the character of the decontamination problem will save time and money and increase the efficacy of decontamination. (authors)
Monitoring and understanding of corrosion on nuclear sites plays a key role in safe asset management and supporting informed choice of decontamination methods for steels due for decommissioning. Recent advances in Quartz Crystal Nano-balance (QCN) technology offer a means to monitor corrosion in-situ in radiologically harsh environments, in real time and with high sensitivity. Oxalic acid has been widely used in nuclear plants and installations as a corrosion inhibitor for carbon steels and as a decontamination cleaning agent due to its ability to remove rust from the surface of ferritic metals and alloys. As an exemplar system for decontamination, the corrosion behavior of mild carbon steel and pure iron samples in 1 wt% to 8 wt% oxalic acid solutions have, for the first time, been measured and compared in real time and in situ using the QCN. Corrosion rates measured using the QCN are found to agree with those obtained using corrosion current (i{sub CORR}) measurements, with the added advantages of: (i) real time and potentially in situ and higher sensitivity measurement; (ii) reduced uncertainty in the conversion of the QCN measured frequency change to a mass change-based corrosion rate compared to the conversion of the iCORR measured by LSV with Tafel extrapolation to similar; (iii) the provision of mechanistic insights into the action of oxalic acid on Fe-rich steels. We have also used the QCN to study the impact of radiolytically generated peroxide on the corrosion protection afforded by oxalate to Fe surfaces during oxalic acid-driven tank clear out. In so doing we have identified H{sub 2}O{sub 2} and oxalate concentrations under which that protection breaks down and elucidated the Fenton reaction assisted mechanism by which that breakdown occurs. (authors)
The Colonie Formerly Utilized Sites Remedial Action Program (FUSRAP) Site is located in the Town of Colonie, Albany County, New York. The U.S. Army Corps of Engineers (USACE) is currently addressing environmental contamination associated with the Site. The area surrounding the Site consists of residential and commercial properties, known as vicinity properties (VPs). Cleanup activities have been completed on many of these VPs under the FUSRAP to address depleted uranium contamination. Soil remediation activities have been substantially completed at the Colonie FUSRAP Site and its VPs under the FUSRAP. Recent studies performed by an independent party and under FUSRAP identified uranium within indoor dust in residencies and businesses in the immediate vicinity of the Site. The studies were limited to non-living areas such as basement window sills, garages, and attics. This paper discusses the indoor dust sampling and analysis, in support of the Remedial Investigation (RI) for the VPs, and presents sampling results. The indoor dust sample media presented many technical challenges regarding sampling design, data reduction, and data interpretation. In addition, because the RI is focused on numerous resident-owned, rental, and commercial properties, challenges where presented regarding right-of-entry to sample. Isotopic uranium ratios observed in the majority of the samples are indicative of the depleted uranium contaminant, even at trace levels. While the sampling and analysis methods were effective at identifying depleted uranium in the majority of the samples, preliminary property-specific risk assessment results do not indicate the presence of depleted uranium in sufficient concentrations to pose unacceptable risk to VP inhabitants. (authors)
Report for NDEP
Report prepared for NDEP
The alpha incinerator has been operating since 1999 at the CEA Valduc center in France for the treatment of alpha-bearing technological waste. The fact that the incinerator has been working smoothly for 18 years and the experience gained during this period indicate that it can also be used to treat other types of waste, such as Ion-Exchange Resin (IER) suspensions. The aims of an R and D project initiated in 2014 were to develop a dosage system allowing these suspensions to be injected into the heart of the treatment system and to evaluate the performance of the incinerator when these materials are added to technological waste. This article describes the work carried out to develop a dosage system for heavily particle-laden fluids (with more than 50 vol% solid particles), with the aim of delivering waste continuously into the treatment furnace. The proposed device consists of a feeding tank equipped with a stirrer, a piston pump, and a pneumatic transport system. Reliability has been improved by replacing the initial sealing system (a piston with seals), by a very tight (∼4 μm gap), therefore seal-less, sleeve/piston unit. Adjusting the carrying gas flow has optimized the system as a whole, making it safer and more robust. The system has been qualified through more than 1000 hours of operation and the results obtained for the incineration of IER suspensions suggest that industrial transport is feasible and will thus begin soon. (authors)
In many radiological groundwater pathway assessments, especially those where the assessment timescales of interest are relatively short (say a few thousand years or less), contributions to effective dose or radiological risk are dominated by radionuclides such as C-14, Cl-36 or I-129. Over longer timescales, additional radionuclides can also become key contributors to risk. In particular, members of the U-238 decay chain, notably Ra-226 and Pb-210, are likely to be key radionuclides. Other decay chains that can contribute significantly to dose or risk at times far into the future include Np-237 → U-233 → Th-229 and U-235 → Pa-231 → Ac-227. In this paper, a method is described for understanding decay chain behaviour in radiological assessments. The method uses a graphical approach in which the various modes of transport and decay in a system of connected compartments are represented as pathways between two nodes in a two-dimensional grid. Each pathway corresponds to a distinct transport and decay process. By so doing, the different transport and decay processes can be identified in a systematic way. The result is an algorithm for generating the contributions to effective dose or radiological risk without explicit solution of the transport equations. The method has been tested against numerical models and analytic solutions and found to give excellent agreement, while at the same time providing information about decay chain behaviour that would be difficult to obtain from a numerical assessment model. The power of the method is illustrated by applying it to some examples based on real repository concepts. (authors)
Maxine Onsite: Developed to estimate dose to individuals who are working onsite but are not site employees. Follows the methodologies discussed in US NRC Regulatory Guides 1.109 and 1.111 to determine dose from a chronic atmospheric release. Determines the dose given relative air concentrations and deposition concentrations as input. We look at four locations onsite that may be accessed by members of the public. To show compliance with the EPA and DOE public dose limit of 10 mrem/yr, determining who is a member of the public or a worker onsite is necessary. SRS has defined a member of the public for NESHAPS and DOE O 458.1. Maxine Onsite runs on Microsoft Windows Operating System through a Microsoft Excel spreadsheet. Input from the user includes parameters that are variable such as air concentrations, and fixed, such as distance to the receptor and elemental iodine fraction. Maxine Onsite was developed from Maxine which is a program meant to calculate dose to the MEI via three pathways, external, inhalation, and ingestion. Maxine Onsite is meant for looking at the exposure through the external and inhalation pathways only, no local food production onsite. The ways that Maxine Onsite is used to calculate the dose to the MEI includes the following: - Determining the respective air concentration values at each location using distances from the release stack; - Breathing rates for the MEI; - Determining the amount of time the MEI is outside; - Determining the plume travel time. The following relative air and ground deposition values for proper execution of the spreadsheet come from MAXDOSE-SR and are needed to accurately determine the dose to the MEI: relative air concentration, relative air concentration decayed by 2.26 days, relative air concentration decayed and depleted for 8 days, and relative deposition. Test cases were designed, developed, and executed to determine the accuracy of Maxine Onsite, which were verified additionally through hand calculations. Several changes were made for testing, including varying air concentrations, distances, breathing rates, and shielding factors. Each test case was then verified through hand calculations to assure the accuracy of the calculated doses. The results from the test cases, as well as the default parameters, can be used for benchmarking Maxine Onsite in the future. Maxine Onsite performs as expected and produces correct and accurate results at each of the different locations onsite (TRL, B-Area Barracks, SRELCC, and Gunsite 51) for varying test cases. The input required by the user is minimal and includes the results of the dose to the MEI on the first page for ease of access. Future plans for Maxine Onsite include adding in the ingestion pathway and adding in atmospheric dispersion estimates to the spreadsheet.
Annual report required by DOE Order 435.1
Report prepared for NDEP