“Various waste forms are to be placed into the mined geologic disposal system, or federal repository, for ultimate disposition,” says Robert Sindelar, Ph.D., manager, Materials Applications and Process Technology Group, Savannah River Technology Center, Aiken, S.C. “The behavior of these waste forms, in terms of corrosion, dissolution, and material reconfiguration is essential for the performance assessment and criticality analyses for the disposal system. Aluminum-based fuels are one category of spent nuclear fuel destined for repository disposal. The aluminum-based fuels differ greatly from the commercial-spent nuclear fuels in that they are highly enriched in uranium and that the fuel microstructure is heterogeneous.”

The first ASTM standard guide for testing U.S. Department of Energy (DOE) spent nuclear fuels for the repository is available. ASTM C 1431, Standard Guide for Corrosion Testing of Aluminum-Based Spent Nuclear Fuel in Support of Repository Disposal, will assist scientists with test plans for waste-form behavior, and in particular, metallic-fuel behavior. DOE contract organizations that compile data sets of information on waste-forms for licensing of the repository can refer to C 1431.

“This guide provides the template for testing of fuel behavior under repository conditions. A suite of tests and information to be collected are provided in the guide,” says Sindelar, who helped to develop the guide with a task group of ASTM Subcommittee C26.13 on Repository Waste, part of Committee C26 on Nuclear Fuel Cycle.

Task group members include “program managers and senior scientists from the Savannah River Technology Center, Idaho National Environmental and Engineering Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and the U.S. DOE,” he says.

As stated in the guide, C 1431 covers “corrosion testing of aluminum-based spent nuclear fuel in support of geologic repository disposal (per the requirements in 10 CFR 60 and 40 CFR 191). The testing described is designed to provide data for analysis of the chemical stability and radionuclide release behavior of aluminum-based waste forms produced from aluminum-based spent nuclear fuels. The data and analyses from the corrosion testing will also support the technical basis for inclusion of aluminum-based spent nuclear fuels in the repository source term. Interim storage and transportation of the spent fuel will precede geologic disposal; therefore, the requirements for interim storage (per 10 CFR 72) and transportation (per 10 CFR 71) are referenced. The analyses that will be based on the data developed are also necessary to support the safety analyses reports (SARs) and performance assessments (PAs) for disposal systems.”

“The information obtained on waste form behavior is part of the technical basis for licensing the repository,” concludes Sindelar. “In using ASTM consensus standards, the licensee strengthens the acceptability of the license package by the licensing agency and the stakeholders.”

ASTM standards are available by calling Customer Service (610/832-9585) or through the Web site.

For further technical information, contact Robert Sindelar, Ph.D., Manager, Materials Applications and Process Technology Group, Westinghouse Savannah River Co., Savannah River Technology Center, Bldg. 773-41A, Aiken, S.C. 29808 (803/ 725-5298). Committee C26 meets June 26-28 in Las Vegas, Nev. For meeting or membership information, contact manager Felicia Quinzi, ASTM (610/832-9738). //

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