Environmental Risk Assessment Work Plan For The Hanford Tank Waste Treatment And Immobilization Plant

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Download or read book River Protection Project System Plan written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Department of Energy (DOE), Office of River Protection (ORP) manages the River Protection Project (RPP). The RPP mission is to retrieve and treat Hanford's tank waste and close the tank farms to protect the Columbia River. As a result, ORP is responsible for the retrieval, treatment, and disposal of approximately 57 million gallons 1 of radioactive waste contained in the Hanford Site waste tanks and closure2 of all the tanks and associated facilities. The previous revision of the System Plan was issued in May 2008. ORP has made a number of changes to the tank waste treatment strategy and plans since the last revision of this document, and additional changes are under consideration. ORP has contracts in place to implement the strategy for completion of the mission and establish the capability to complete the overall mission. The current strategl involves a number of interrelated activities. ORP will reduce risk to the environment posed by tank wastes by the following: (1) Retrieving the waste from the single-shell tanks (SST) to double-shell tanks (DST) and delivering the waste to the Waste Treatment and Immobilization Plant (WTP). (2) Constructing and operating the WTP, which will safely treat all of the high-level waste (HLW) fraction contained in the tank farms. About one-third of the low-activity waste (LAW) fraction separated from the HLW fraction in the WTP will be immobilized in the WTP LAW Vitrification Facility. (3) Developing and deploying supplemental treatment capability assumed to be a second LAW vitrification facility that can safely treat about two-thirds of the LAW contained in the tank farms. (4) Developing and deploying supplemental pretreatment capability currently assumed to be an Aluminum Removal Facility (ARF) using a lithium hydrotalcite process to mitigate sodium management issues. (5) Developing and deploying treatment and packaging capability for contact-handled transuranic (CH-TRU) tank waste for possible shipment to and disposal at the Waste Isolation Pilot Plant (WIPP) in New Mexico. (6) Deploying interim storage capacity for the immobilized high-level waste (IHLW) pending determination of the final disposal pathway. (7) Closing the SST and DST tank farms, ancillary facilities, and all associated waste management and treatment facilities. (8) Optimizing the overall mission by resolution of technical and programmatic uncertainties, configuring the tank farms to provide a steady, well-balanced feed to the WTP, and performing trade-offs of the required amount and type of supplemental treatment and of the amount of HLW glass versus LAW glass. ORP has made and continues to make modifications to the WTP contract as needed to improve projected plant performance and address known or emerging risks. Key elements needed to implement the strategy described above are included within the scope of the Tank Operations Contract (TOC). Interim stabilization of the SSTs was completed in March 2004. As of April 2009, retrieval of seven SSTs has been completed and retrieval of four additional SSTs has been completed to the limits of technology. Demonstration of supplemental LAW treatment technologies has stopped temporarily pending revision of mission need requirements. Award of a new contract for tank operations (TOC), the ongoing tank waste retrieval experience, HLW disposal issues, and uncertainties in waste feed delivery and waste treatment led to the revision of the Performance Measurement Baseline (PM B), which is currently under review prior to approval. 6 This System Plan is aligned with the current WTP schedule, with hot commissioning beginning in 2018, and full operations beginning in late 2019. Major decisions regarding the use of supplemental treatment and the associated technology, the ultimate needed capacity, and its relationship to the WTP have not yet been finalized. This System Plan assumes that the outcome of these decisions will be to provide a second LAW vitrification facility. No final implementation decisions regarding supplemental technology can be made until the Tank Closure and Waste Management Environmental Impact Statement is completed and a Record of Decision is issued by DOE. Technical solutions are being developed to mitigate the impact from substantially increased estimates of sodium to be added during pretreatment of the tank waste solids. This may involve one or more of the following options: (1) refining or modifying the flowsheet to reduce the required amount of additional sodium, (2) increasing the overall LAW vitrification capacity, (3) increasing the incorporation of sodium into the LAW glass, (4) increasing the incorporation of aluminum in the HLW glass to reduce caustic leaching requirements, or (5) implementing other technical solutions. For planning purposes, the PMB assumes that option (5) above, in the form of an ARF, will be successful in reducing the sodium required to be added during pretreatment of the tank waste.