Abstract
Analysis of three sodium-cooled fast microreactors (SFMs) with thermal powers of 10, 30, and 50 MWt showed that smaller reactors result in lower radiological consequences during a postulated sabotage-induced event because of their reduced core inventory. All SFMs used U-10Zr metal fuel enriched to 15 wt% high-assay low-enriched uranium and operated until their respective effective multiplication factor (keff) reduced to less than 1 or until the end of their operational lifespan. Sabotage scenarios were simulated at this point, when the fuel inventory within the core contains the highest-level of radioactivity. Radionuclide core inventories were calculated using the SCALE code at shutdown and 3 days post-shutdown. Dose consequence analyses were performed for three sabotage scenarios using the RASCAL tool. As microreactor developers plan for minimal on-site or complete off-site emergency response, it remains essential to evaluate their physical protection needs and potential hazards, including assessing postulated sabotage-induced events that could become more relevant. SFM licensees should identify a credible worst-case, major accident, estimate release source terms, and perform dose consequence analyses to evaluate site-specific physical protection measures. This recommendation supports a risk-informed, performance-based approach, aligning with applicable regulatory requirements, i.e., 10 CFR Parts 100 and 53 rulemaking in the United States.
| Original language | English |
|---|---|
| Article number | 114360 |
| Journal | Nuclear Engineering and Design |
| Volume | 444 |
| DOIs | |
| State | Published - Dec 1 2025 |
Funding
This work was supported by the Advanced Reactor Safeguards and Security Program in the US Department of Energy ’s Office of Nuclear Energy . The authors would also like to thank the subject matter experts at Oak Ridge National Laboratory and Sandia National Laboratories for their valuable review of this article. This work was supported by the Advanced Reactor Safeguards and Security Program in the US Department of Energy's Office of Nuclear Energy. The authors would also like to thank the subject matter experts at Oak Ridge National Laboratory and Sandia National Laboratories for their valuable review of this article. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (https://energy.gov/downloads/doe-public-access-plan).
Keywords
- Consequence
- Emergency response planning
- Physical protection
- Sabotage
- Sodium-cooled fast microreactor