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The Operational Importance of Radiological Improvements in Remote Handled Transuranic Waste Processing at the Idaho Cleanup Project-11055
| Content Provider | Semantic Scholar |
|---|---|
| Author | Anderson, Scott Hobbes, Tammy L. Jines, Alan Lattin, William Lusk, Gary Ziemianski, Edward J. Falls, Idaho |
| Copyright Year | 2011 |
| Abstract | For purposes of disposal at the Waste Isolation Pilot Plant (WIPP), Remote Handled Transuranic (RH TRU) waste is defined as transuranic waste that exhibits a dose equivalent rate of > 200 millirem/hour (mrem/hr) and < 1,000 mrem/hr at the surface of the container holding the waste. With the currently established occupational dose limit for general employees at 5 rem/year and a company set administrative control limit of 700 mrem/year, a variety of engineered and administrative controls have been implemented within each waste management facility to ensure facility workers remain within these limits while handling and processing RH TRU waste for disposal at WIPP. In 2005, workers began the task of retrieval of 675 RH TRU drums from below ground storage vaults for processing and disposal at WIPP in accordance with the scope established by the United States Department of Energy (US DOE) in the Idaho Cleanup Project (ICP) contract. This waste, generated during the 1970s, 1980s and 1990s, was generated at Argonne National Laboratory – East, as well as other locations at the Idaho National Laboratory (INL), from the examination of irradiated and un-irradiated fuel pins and other reactor materials from various reactor programs at Argonne National Laboratory – West and other US DOE reactor sites. Once retrieved, the drums were transported in shielded transfer containers across the Idaho desert to the ultimate processing location at the Idaho Nuclear Technology and Engineering Center (INTEC). Existing “hot cell” facilities were renovated and placed into service to be able to safely process the RH TRU waste drums, while still being protective of the health and safety of the worker. The highest recorded dose equivalent rate at the time the drums were placed into storage was 52 rem/hr at the container surface. Throughout the process, from inception through to final disposition, radiological control was a key element of the design, fabrication, and operation of equipment needed to complete the job. Based upon the success of this effort, beginning in mid-2009, the US DOE provided the opportunity to process an additional 160 canisters and large liners containing RH TRU waste, also generated decades ago. This waste, generated during the 1970s through late 2007, has been in underground storage vaults for nearly that long, and is currently being retrieved and transported to INTEC, where processing is already underway. This added work scope provides new challenges in the form of waste containers that are much larger in size than the original drums and possess significantly higher dose equivalent rates (the highest recorded dose equivalent rate at the time of storage was reported to be 20,000 rem/hour at the surface of the container) causing additional concern for worker protection during processing. As a result, a variety of initiatives are being implemented to enhance the RH TRU waste processing capabilities based on lessons learned from the initial campaign and from the rest of the US DOE complex. This paper details the genesis of the RH TRU waste processing approach, the role that radiological control practices played in the approach, and the benefits provided to the workforce by having a robust radiological control program. INTRODUCTION AND HISTORY The INL began providing interim storage of RH TRU waste in 1976 for eventual characterization, certification, packaging, and transportation to a final disposition location. The waste was originally stored in underground storage vaults located at the Intermediate Level Transuranic Storage Facility (ILTSF) within the facility boundary of the Radioactive Waste Management Complex (RWMC). The ILTSF was constructed in 1976 for the purpose of providing a location for intermediate storage prior to ultimate disposition. The ILTSF consists of 256 below-grade steel vaults that stored between 5 and 11 drums each. The initial inventory of RH TRU waste for disposition was slightly over 80 m (675 drums) and is summarized in Table I. Beginning in 2005, retrieval from these underground storage locations was initiated. The drums of RH TRU were retrieved and placed in temporary above ground storage in specially fabricated Interim Storage Containers (ISC) and/or Shielded Overpacks (SO) while waiting transport to INTEC for further processing. WM2011 Conference, February 27March 3, 2011, Phoenix, AZ Argonne National Laboratory-East (ANL-E) sent 617 30-gal waste drums with a total volume of 70.4 m3 waste from 1976 through 1995 to the RWMC. The waste consisted of mixtures of combustible and noncombustible waste. The ANL-E RH TRU waste was generated at the Alpha Gamma Hot Cell Facility as a result of the destructive examination of experimental fuel and associated materials at that facility between 1976 and 1995. The Materials and Fuels Complex (MFC) generated and sent four 55-gal drums in 1988. The waste consisted of glassware, paper, polyethylene, and miscellaneous laboratory waste. From 1977 through 1981, the Naval Reactors Facility (NRF) sent 3.1 m3 of RH TRU waste to the RWMC for temporary disposal. The waste in these 27 containers includes process equipment, containers, and combustible materials. Three shipments were sent from the Test Reactor Area (TRA) to the RWMC from 1990 through 1996, for a total of 5.2 m3 (25 containers). In 1990, 10 drums of waste from the drains of TRA Hot Cells and the Alpha Wing Laboratories were sent for disposal. In 1994, 14 drums of RH TRU waste were sent from the TRA to the RWMC. The waste consisted of resin from the mixed bed ion exchange columns at TRA 605. The last shipment occurred in 1996 and consisted of several radioactive sources. One shipment of RH TRU waste from INTEC was sent to RWMC for storage in 1978. The waste was packaged in two 30-gal drums and was generated from the analysis of irradiated fuel. The waste consisted of glass, plastics, and metal; miscellaneous laboratory equipment; and diatomaceous earth. Table I – Inventory of RH TRU Generating Source Storage Configuration Quantity (drums) Form Maximum Dose equivalent rate (rem/hour @ container surface) Average Dose equivalent rate (rem/hour @ container surface) Argonne National Lab – East 30-gallon drum 617 Debris Naval Reactors Facility 30-gallon drum 27 Debris Idaho Nuclear Technology and Engineering Center 30-gallon drum 2 Debris Materials and Fuels Complex (formerly ANL West) 55-gallon drum 4 Debris Advanced Test Reactor Complex (formerly Test Reactor Area) 55-gallon drum 25 10 Solid, 15 Debris 52 3.6 Because of the success of the initial processing effort, beginning in 2009, the US DOE identified an additional population of RH TRU waste to be processed in existing facilities. With the added boost of American Recovery and Reinvestment Act (ARRA) funding, planning for processing this additional RH TRU waste inventory began. This waste population consists of 160 containers, largely consisting of 6 foot tall, 12 inch diameter canisters generated from the Materials and Fuels Complex (formerly known as ANL-W), ANL-E, and Bettis Atomic Power Laboratory (BAPL). Table II provides a summary. The Hot Fuel Examination Facility (HFEF) canisters from MFC were generated during “hot cell” and analytical chemistry operations conducted in various “hot cell” locations from April 1977 to September 2007. Waste from WM2011 Conference, February 27March 3, 2011, Phoenix, AZ these operations was generated primarily in support of Liquid Metal Fast Breeder Reactor and Integral Fast Reactor irradiation studies performed on alloy fuel, and sample materials irradiated in the Experimental Breeder Reactor (EBR)-II. The waste consists predominantly of organic and inorganic debris waste generated during the examination of irradiated fuels. The waste from ANL-E is similar in generation origin to the drums described in Table I above, and includes fissile scrap, recoverable and non-recoverable, segregated from intermediate level TRU waste shipped to INL in the 30gallon drums. These “scrap” materials have since been determined to be waste. The waste was originally packaged and shipped to INL between March 1975 and November 1995. Waste from this stream was contaminated primarily with fissile materials and mixed fission products. Table II – Additional Inventory of RH TRU Generating Source Storage Configuration Dimensions Quantity (containers) Maximum Dose equivalent rate (rem/hour @ 30 cm) Average Dose equivalent rate (rem/hour @ 30 cm) HFEF canister 12.75” dia. X 73.5” long 86 1,490 39 Large Liners 24” dia. X 13’ 8” long 12 52 9.4 SLSF canister 22” dia. X 134” long 8 355 107 Boxes 4’ X 4’ X 7’ 3 0.06 0.05 MFC (formerly known as ANL-W) EBR donut liner 24” dia. X 76” long 1 0.03 0.03 Argonne National Lab – East ANL-E canister 9.25” dia. X 72” long 48 183 134 Bettis Atomic Power Lab HFEF canister 12.75” dia. X 73.5” long 2 5 3 Until recently, all of these containers had been safely stored in underground storage vaults at the MFC Radioactive Scrap and Waste Facility. To date, 149 of the containers have been successfully retrieved (all except for 9 of the Large Liners and 2 of the SLSF canisters) and transported to INTEC for processing. Of the 139 containers, 105 have been successfully processed through December 2010. DESCRIPTION OF THE PROCESS The work includes opening the original containers, removal of items that are prohibited by WIPP, sampling when required, sampling and analysis of headspace gases, conducting real-time radiography (RTR) to examine and document the contents of the containers, and finally, measurement of radiological characteristics to estimate the quantities of radionuclides present via a Dose-to-Curie (DTC) conversion. The equipment necessary to perform the RTR and DTC is configured to accept 30-gallon and 55-gallon drums. All waste in containers of other dimensions destined for disposition at WIPP is repackaged to allow for the characterization and transportation process. For repackaging, the original container is pl |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://archive.wmsym.org/2011/papers/11055.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
