Audit Report: DOE-OIG-19-17

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February 19, 2019

Interim Storage of Radioactive Canisters at the Savannah River Site

The Department of Energy’s Savannah River Site became operational in 1951 and produces nuclear materials for national defense, research, medical, and space programs.  The separation of fissionable nuclear material from irradiated targets and fuels results in the generation of liquid radioactive waste, which is stored in underground storage tanks at the site.  The Savannah River Operations Office is responsible for the day-to-day oversight of the Department’s Office of Environmental Management (Environmental Management) operations at the Savannah River Site.

In 1996, the Defense Waste Processing Facility (DWPF) at the Savannah River Site began stabilizing the high-level radionuclides in the liquid radioactive waste through a vitrification process that immobilizes the waste in a borosilicate glass matrix within a stainless steel canister.  The radioactive canisters are then stored on an interim basis on-site while awaiting final shipment to a yet-to-be-determined permanent off-site Federal repository.  There are currently two canister storage buildings on the Savannah River Site, Glass Waste Storage Buildings #1 and #2.

At the end of calendar year 2017, DWPF operations had produced 4,159 radioactive canisters.  The Savannah River Operations Office estimates that a total of 8,170 radioactive canisters will be produced through the end of the treatment process, currently estimated to be completed by 2036, resulting in a single stack canister storage capacity shortfall for 3,580 radioactive canisters.  Since 2010, Environmental Management has considered several different strategies to increase its interim storage capacity, including the construction of a third canister storage building, and more recently, double stacking the canister storage positions in Glass Waste Storage Building #1.  Because the canisters need to be safely stored until a permanent repository is identified, we initiated this audit to determine whether Environmental Management had developed an effective strategy for providing adequate interim storage for radioactive canisters at the Savannah River Site.

While Environmental Management had considered several interim storage strategies, the decision to double stack radioactive canisters in Glass Waste Storage Building #1 and single stack radioactive canisters in Glass Waste Storage Building #2 may not provide adequate interim storage capacity to accommodate planned DWPF radioactive canister production through 2036.  We determined that Environmental Management selected this strategy without first resolving several uncertainties.  We acknowledge that the Department has a strategy for the interim storage of radioactive canisters that allows DWPF to currently accomplish mission requirements.  However, in light of the uncertainties associated with the double stacking strategy, the Savannah River Operations Office may need to develop additional interim radioactive canister storage capacity sooner than Environmental Management’s expected date of 2029.  As such, we made three recommendations to assist Environmental Management with developing and implementing a strategy for the interim storage of radioactive canisters at the Savannah River Site.

Topic: Environmental Cleanup