The purpose of this report is to develop and analyze the Engineered Barrier System (EBS) Radionuclide Transport Abstraction Model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment: Engineered Barrier System: Radionuclide Transport Abstraction Model Report (BSC 2006 [DIRS 177739]). The EBS Radionuclide Transport Abstraction (or RTA) is the conceptual model used in the Total System Performance Assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ).

The U.S. Nuclear Regulatory Commission (NRC) is evaluating the safety and security of spent nuclear fuel (SNF) stored in dry casks for extended time periods before transportation to a location where the SNF is further processed or permanently disposed.

Following the proposals for nuclear fuel assurance of International Atomic Energy
Agency (IAEA) Director General Mohamed ElBaradei, former Russian President Vladimir V.
Putin, and U.S. President George W. Bush, joint committees of the Russian Academy of
Sciences (RAS) and the U.S. National Academies (NAS) were formed to address these and other
fuel assurance concepts and their links to nonproliferation goals. The joint committees also
addressed many technology issues relating to the fuel assurance concepts. This report provides