  This study presents a cross-disciplinary reactor-to-repository framework to
compare different advanced reactors with respect to their spent nuclear fuel
(SNF). The framework consists of (1) OpenMC for simulating neutronics, fuel
depletion, and radioactive decays; (2) NWPY for computing the repository
footprint for SNF disposal given the thermal constraints; and (3) PFLOTRAN for
simulating radionuclide transport in the geosphere to compute the peak dose
rate, which is used to quantify the repository performance and environmental
impact. We first perform the meta-analysis of past comparative analyses to
identify the factors led previously to inconsistent conclusions. We then
demonstrate the new framework by comparing five reactor types. Significant
findings are that (1) the repository footprint is neither linearly related to
SNF volume nor to decay heat, due to the repository's thermal constraint, (2)
fast reactors have significantly higher I-129 inventory, which is often the
primarily dose contributor from repositories, and (3) the repository
performance primarily depends on the waste forms. The TRISO-based reactors, in
particular, have significantly higher SNF volumes, but result in smaller
repository footprints and lower peak dose rates. Our analysis highlights the
diversity of these reactors, each of which should be evaluated individually.
The open-source framework ensures proper cross-disciplinary connections between
reactor simulations and environmental assessments, as well as the
transparency/traceability required for such comparative analyses. It aims to
support reactor designers, repository developers and policy makers in
evaluating the impact of different reactor designs, with the ultimate goal of
improving the sustainability of nuclear energy systems.
