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Holifield Accelerator SF 6 and Other Disposition

Holifield Accelerator SF 6 and Other Disposition. Department of Energy Accelerator Safety Workshop August 21-23, 2018 B. Alan Tatum Stable Isotopes Production Manager Oak Ridge National Laboratory. Outline.

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Holifield Accelerator SF 6 and Other Disposition

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  1. Holifield Accelerator SF6 and Other Disposition Department of Energy Accelerator Safety Workshop August 21-23, 2018 B. Alan Tatum Stable Isotopes Production Manager Oak Ridge National Laboratory

  2. Outline • Overview of the Holifield Radioactive Ion Beam Facility (HRIBF) • HRIBF Disposition Effort • SF6 Removal • Lessons Learned • Summary

  3. HRIBF Historical Timeline • The Holifield Radioactive Ion Beam Facility, located at the Oak Ridge National Laboratory in Oak Ridge, TN, and its predecessors provided unique accelerated light, heavy, and short-lived radioactive ion beams for nuclear structure and reaction studies, astrophysics research, and interdisciplinary applications from 1962 until 2012. • The Facility advanced nuclear physics over five decades, grouped into three distinct eras: • 1962 - 1980: Oak Ridge Isochronous Cyclotron (ORIC) • 1981 - 1992: Holifield Heavy Ion Research Facility (HHIRF) • 1993 - 2012: Holifield Radioactive Ion Beam Facility (HRIBF), the first radioactive beam facility in the U.S.

  4. HRIBF Capabilities • Produced high-quality post-accelerated beams of unstable nuclei, or Radioactive Ion Beams (RIBs), and was the only facility of its type in the U.S. • A national user facility for RIB science funded by the DOE Office of Nuclear Physics • 570 member Users group • Primary research programs in Nuclear structure & reactions and Nuclear astrophysics • Typically operated on a 5 day 24 hour schedule, 4500 total research hours per year • Had capabilities that were unique worldwide including beams of n-rich fission fragments at energies above the Coulomb barrier • Helped to develop ISOL RIB science in the U.S. & worldwide • Pioneering techniques and technology • ISOL team made many world-leading developments • Provided world-class research tools • Helped to establish, and maintain an international user base for the FRIB era • Applied core capabilities in nuclear science to problems of relevance to society

  5. Science at HRIBF • High-quality beams of 200 rare isotopes, more than 50 at world-record intensity, were used in groundbreaking experiments including the first measurement with a reaccelerated unstable beam in North America, and the first acceleration of neutron-rich fission fragments leading to confirmation of the doubly-magic nature of tin-132. • 175 post-accelerated RIB species available • 32 proton-rich species • 143 neutron-rich species • (+26 more non-post-accelerated) Beam list increased by ~60% after 2003

  6. Isotope Separator On-Line (ISOL) RIB Production Process

  7. HRIBF Systems • RIB Production: • Oak Ridge Isochronous Cyclotron (ORIC) • IRIS1: RIB production station • IRIS2: RIB production station (new in 2010) • 25 MV Tandem electrostatic accelerator • ISOL Development: • 3 off-line Ion Source Test Facilities (ISTF1,2,3) • 1 low-power On-Line Test Facility (OLTF) • 1 high-power On-Line Test Facility (HPTL) • Experimental End Stations • Recoil Mass Spectrometer (RMS) • Daresbury Recoil Separator (DRS) • Enge Spectrograph • Low Energy Radioactive Ion Beam Spectroscopy Station (LeRIBSS) • Several general purpose end stations

  8. ORIC • 1960’s vintage • Azimuthally-Varying-Field (AVF) cyclotron • Unique vertical configuration • Served as the driver accelerator for RIB production

  9. 25-URC Tandem Accelerator • Manufactured by National Electrostatics Corporation • Unit Reverse Conservative (27 units for 25 MV, with folded configuration) • SF6 insulation • Optic elements, strippers, and diagnostics in two major dead sections and the terminal • During the voltage test of the Tandem in May 1979, a record 32 MV was attained without accelerating tubes installed. The voltage is still the highest sustained man-made potential difference. • The Tandem operated at 25.5 MV with accelerating tubes installed, the highest voltage ever achieved for any electrostatic accelerator.

  10. IRIS1 and IRIS2/HPTL RIB Production Systems • 2-stage mass separation • M/DM ~ 1000 • M/DM ~ 20000 • Robotic handling of activated targets & ion sources • Designed for thick, thin & liquid targets • Beam rastering • Laser purification of RIBs T106 Lasers C118 IRIS1 Production Platform IRIS2/HPTL Production Platform

  11. HRIBF Closure • HRIBF management was notified in January 2011 of the Office of Science decision to close HRIBF • The facility operated until April 15, 2012 for the completion of high-priority PAC-approved experiments • The Tandem was periodically operated until 2016 on a full-cost-recovery basis during facility disposition

  12. HRIBF Disposition Plan • A plan was developed to • minimize cost to the DOE-NP program, • maximize research potential, • provide for long term efficiency of operations, • improve synergy within the Physics Division/NP-funded programs, • eliminate the primary hazards, risks and liabilities for all stakeholders, • avoid having an “abandoned” building, • repurpose and recycle where possible, • provide the most positive solution for all parties: DOE-NP, ORNL, the ORNL Physics Division, and DOE-OSO. • Total cost of disposition efforts: ~$27M • Timeframe: FY2012-FY2018

  13. HRIBF Facility Disposition Process • Historic Property Review (building and research equipment) • Initial phase consisted of removing obsolete equipment and chemicals • Cataloging of equipment by HRIBF staff (submitted January 2014) • DOE-NP issued a Call for Proposals for the HRIBF equipment on July 10, 2014 • Award of proposals to various institutions including ORNL • Systematic removal and transfer of complete systems • Transfer of individual components • Equipment not requested or awarded was excessed or disposed as waste

  14. Accelerator Facility Layout Retained Systems Partially Dismantled ORIC Accelerator Tandem Accelerator Fully Dismantled IRIS1 RMS ISIS OLTF DRS LeRIBSS IRIS2/HPTL ISTF1, (2nd floor), ISTF2 (6010), ISTF3 (6010) not shown

  15. Hazards Mitigated and Spaces Repurposed • The SF6 has been removed and the oxygen deficiency monitoring system removed from service. • The most radiologically activated and contaminated spaces in the facility have been addressed: these are ORIC and IRIS1. All used target/ion source assemblies have been dispositioned. • Electrical safety risks have been drastically reduced by removing substantial amounts of old wiring and electrical distribution equipment, particularly associated with the 1960s vintage ORIC. • Chemical and radiological source inventories have been reduced to the minimum level needed by the remaining experimental programs. • Lead stockpiles eliminated. • Vacated spaces decontaminated from radiological surface contamination, lead, and beryllium. Asbestos that was removable has been eliminated. • DOE-NP equipment removed from shop and storage warehouse spaces. • HRIBF spaces in adjacent Building 6010 have been emptied, cleaned, and much of the space has been repurposed by other programs. • The large vault spaces in Building 6000 have been evaluated by ORNL for potential use by other programs.

  16. Waste: virtually every type • Dry active waste • Radiological waste • RCRA • TSCA • Mixed • Chemicals • Liquids • Metals (constrained by the scrap metal moratorium)

  17. Equipment Transfers • Disassemble equipment • Radiological Surveys • High Risk Property Review • Hazardous Materials Review • Identify existing DOE Grant (equipment remains DOE property) • Obtain Site Office approval • Pack equipment • Ship

  18. Equipment Transfers/Shipments to 16 Institutions • US Army: 1 shipment complete • Brookhaven National Laboratory: 1 shipment complete • Lawrence Berkeley National Laboratory (LBNL): 1 shipment complete, 1 in progress (rad) • Indiana University: 1 shipment complete • Thomas Jefferson National Accelerator Facility (JLAB): 2 shipments complete • Michigan State University / FRIB: 6 shipments complete, 1 shipment in progress • ORNL nEDM: 1 shipment complete • Rutgers University: 1 shipment complete • Texas A&M University: 5 shipments complete • Triangle Universities Nuclear Laboratory (TUNL): 3 shipments complete • University of Michigan: 1 shipment compete, 1 shipment in progress • University of Missouri: 2 shipments complete • University of Notre Dame: 2 shipments complete, 2 in progress (rad and non-rad) • Yale University: 1 shipment complete • Tennessee Tech University: 1 shipment complete (ISTF1 claimed from LEDP) • Concorde Specialty Gases: 1 shipment complete (multiple tube trailers of purchased SF6 inventory) Total of 30 transfers/shipments complete, 4 in progress

  19. SF6 Use at HRIBF • Sulfur hexafluoride (SF6) insulating gas was required for operation of the tandem accelerator to prevent electrical discharge from the high-voltage terminal and accelerating column to the pressure vessel. • SF6 has been used in accelerators, switch gear, and high-voltage power supplies for many years. • Pure SF6 is one of the most stable gases known and is completely non-toxic. • Unfortunately, SF6 is a Greenhouse Gas that requires environmental reporting and special handling and monitoring considerations. Energy of a 25MV spark is ~200 kiloJoules

  20. Tandem SF6 Gas Handling System • The SF6 was re-circulated in gaseous form in the accelerator pressure vessel during operations. • The gas was compressed and stored in liquid form in an adjacent gas storage building during maintenance periods. • Typical 12-hour transfer from the accelerator to storage • Typical 15 hours to get tank back to operating pressure (60-80 psi) • Certified Gas System Operators were required. • The SF6 inventory at HRIBF was determined by a load cell weighing system located in the gas storage building. Inventory at the time of closure was ~200,000 lbs.

  21. Radiological Clearance Requirements and Process • DOE O 458.1, Radiation Protection of the Public and the Environment, specifies the requirements for the clearance of property with the potential to contain residual radioactive material. Clause 4.k.(3).(a) states that property potentially containing residual radioactive material must not be cleared from DOE control unless ”The property is demonstrated not to contain residual radioactive material based on process and historical knowledge, radiological monitoring or surveys, or a combination of these.” • ORNL Radiological Protection Operations used • Process Knowledge • Gas Characterization (elemental chemical analysis) • Analysis for Neutron Activation Products (e.g. chlorine) • Direct Measurements (NaI detectors, ionization chambers, pancake Geiger-Müller detectors, Alpha/beta dual scintillation probe and count-rate meter) • SF6met the criteriafor clearance from DOE control

  22. SF6 Disposition • Radiological Protection Operations at ORNL conducted an extensive analysis over several months with multiple sample surveys to radiologically clear the SF6 for release. • The SF6 was transferred from the Tandem pressure vessel to the three storage tanks and stored in liquid form. • A contract was completed to sell our entire SF6 inventory, almost 200,000 lbs, to Concorde Specialty Gases, Inc. (the same company that purchased the Yale SF6 inventory) following a sealed bid solicitation.   • Nine tube trailers were required to remove all but the residual SF6. • Residual SF6 was transferred to 48 cylinders at ~150 psig. • The transfer process spanned four months. • The transfer process was a tremendous success with no injuries, incidents, or release to the environment!

  23. Lessons Learned • The waste disposal process is challenging when dealing with a wide array of waste streams. Rad and TSCA waste were the greatest challenges. • Waste costs were difficult to project and higher than expected. • “No-Rad-Added” resulted in RCRA/TSCA materials from Rad Areas being disposed as Mixed Waste. • Sampling and analysis (for lead, beryllium, PCBs, asbestos, etc), and radiological surveys (including gamma spectroscopy) are time-consuming and expensive. • Paint on older equipment, piping and facility walls must be sampled for lead, RCRA, and PCBs. • Lead was found in places where lead shielding was never used (paint, solder, cable insulation). • Magnetic components presented various challenges in work planning, staging, and shipping. • Radiological clearance of a substantial quantity of gas was non-trivial. • Building customized crates and packing equipment for re-use is expensive and tedious. • Decommissioning is an emotionally painful process. It requires a very dedicated and conscientious staff to dismantle systems that they have spent much, if not all, of their careers designing, constructing, and operating! Fortunately, we had such as staff, but some people literally worked themselves out of a job.

  24. HRIBF Disposition Status Summary • The multi-year, $27M HRIBF disposition effort is substantially complete without incident, injury or impact to the environment. • We have decommissioned, dismantled, transferred, and/or disposed of • 2 accelerators • 16 beam lines • 1 RIB production platform system • 5 test stands in two buildings • 7 experimental detector system • 200,000 lbs of SF6 • 1 storage warehouse full of equipment • Multiple utility areas and numerous peripheral systems • Facility remains classified as an accelerator facility and is in compliance with DOE Orders including O 420.2C Safety of Accelerator Facilities. • Final step is to complete remaining shipments and complete facility characterization to reclassify from an Accelerator Facility to a Radiological Facility.

  25. ISTF1 Sadly…many empty spaces Tandem Tower IRIS1/C111S Tandem GHS OLTF IRIS1/C111N ORIC Relay Room ORIC/C300 DRS DRS Counting Room

  26. On a Positive Note… APS names Holifield Facility Historic Physics Site • The American Physical Society honored ORNL's Holifield Radioactive Ion Beam Facility as an APS Historic Physics Site. The presentation of a plaque marking the historical designation of the now decommissioned physics research facility kicked off the Nuclear Structure 2016 Conference in Knoxville. • HRIBF is the first designated APS Historic Physics Site in the state of Tennessee. • "In naming the Holifield Radioactive Ion Beam Facility as a Historic Physics Site, the American Physical Society took into consideration the half century of nuclear and atomic physics research performed there, as well as the scores of scientists who performed experiments with its unique capabilities," APS President-elect Laura Greene said. "The Holifield Facility has indeed been an important contributor to the physical sciences history."

  27. Questions?

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