International Review Team Report: A Peer Review of the Yucca Mountain IMARC Total System Performance Assessment EPRI Model

Since 1989, EPRI has been conducting independent assessments of the proposed deep geologic repository for the disposal of spent nuclear fuel and high level radioactive waste at Yucca Mountain, Nevada. EPRI pioneered application of the total system performance assessment (TSPA) approach for evaluating performance of geologic repository systems on a probabilistic basis. Along the way, EPRI developed the Integrated Multiple Assumptions and Release Code (IMARC) as its primary analytical tool for TSPA-based evaluations. Over this two-decade time period, IMARC has been periodically revised to reflect the evolving state of knowledge and the changing programmatic and regulatory environment. In 2007, EPRI commissioned an independent technical peer review of IMARC (as Version 9) by an International Review Team (IRT) in order to evaluate the code's technical basis and implementation relative to EPRI's stated goals. With the exception of formatting for publication and addition of a foreword, the final IRT peer-review report is reproduced here in its entirety without alteration or modification.