Sodium and Lithium Hydride Shields At the Department of Energy's Oak Ridge Reservation - 18412

Conference · Sun Jul 01 00:00:00 EDT 2018

OSTI ID:22977710

Wrapp, John ^[1]

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1. UCOR Manager, Waste Management, URS-CH2M Oak Ridge LLC, East Tennessee Technology Park, P.O. Box 4699, Oak Ridge, TN 37831 (United States)

URS-CH2M Oak Ridge LLC (UCOR) is responsible for cleanup of the U.S. Department of Energy's (DOE) East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee. Formerly known as the K-25 site, the facility enriched uranium for major defense and energy programs for more than 40 years. DOE is seeking the safest, most environmentally protective and fiscally responsible treatment for its large inventory of radioactive-contaminated metals known as 'shields'. The 66 sodium and lithium shields were constructed for use in experiments at the Tower Shielding Facility (TSF), Oak Ridge National Laboratory (ORNL). The TSF operated from 1954 to 1992 and was designed and built for radiation-shielding studies. The shield containers are constructed of aluminum or stainless steel of varying sizes and shapes that were then filled with either sodium metal or lithium hydride material. The historical records indicate the sodium shields were constructed at the Molten Salt Reactor for use in experiments in the 1971 time frame, while the lithium shields were constructed at the Y-12 site and were used in experiments as early as 1961. A subset of the sodium and lithium shields contain depleted uranium. The sodium and lithium shields were initially used at the TSF to perform in-depth measurements of the neutron transport through the shield materials. Based on process knowledge, the shields are managed as radiologically contaminated containers. Efforts have been made over the last fifteen years to find recycle markets for both the sodium and lithium hydride shields. This includes an onsite operation that was initiated at the East Tennessee Technology Park (ETTP) in 2004. After an operational exothermic reaction incident occurred soon after startup, the onsite ETTP recycling action was discontinued and a search for offsite recycling facilities was initiated. In 2016, the Y-12 National Security Complex was contacted regarding recycle/repurpose of the lithium shields; however, the lithium was determined to not be acceptable for their current repurpose process. To date, no offsite recycling outlets have been identified. Recent progress on the waste disposal actions, a shipment of 22 small sodium shields have been shipped and treated offsite. Therefore, the current shield inventory consists of 29 sodium shields located at ETTP and 15 sodium and lithium hydride shields staged at ORNL. The time period needed to reasonably identify safe disposition or recycling outlets for the shields was expected to exceed the one-year Land Disposal Restrictions storage time limit; therefore, approval was received to add the shields to the Site Treatment Plan (STP) in March, 2017. Until a disposition path is found, the shields will continue to be stored in a safe configuration that is protective of human health and the environment. This engineering evaluation identifies and screens the alternatives for dispositioning the shields at the Oak Ridge(ORR). Four alternatives were evaluated including; (1) macro-encapsulation, (2) deactivation, (3) recycle and (4) leave-in-place. An initial screening was performed, and the alternative passing the initial screening are then evaluated in more detail. The evaluation criteria used included environmental risk, technical feasibility, administrative feasibility, worker safety, nuclear safety, transportation safety, and cost. (author)

• Research Organization: WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
• OSTI ID: 22977710
• Report Number(s): INIS-US-20-WM-18412; TRN: US21V0338017755
• Resource Relation: Conference: WM2018: 44. Annual Waste Management Conference, Phoenix, AZ (United States), 18-22 Mar 2018; Other Information: Country of input: France; Available online at: https://www.xcdsystem.com/wmsym/2018/index.html
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALUMINIUM
CONTAMINATION
DEACTIVATION
DECONTAMINATION
DEPLETED URANIUM
ENCAPSULATION
FEASIBILITY STUDIES
LITHIUM
LITHIUM HYDRIDES
MOLTEN SALT REACTORS
NEUTRON TRANSPORT
OAK RIDGE RESERVATION
ORGDP
ORNL
RADIATION PROTECTION
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE STORAGE
RECYCLING
SHIELDING
SODIUM
STAINLESS STEELS
Y-12 PLANT