The MARVEL microreactor, developed at Idaho National Laboratory(INL), has completed an essential phase of cooling system testing, using a non-nuclear facility known as PCAT.
PCAT technology in the MARVEL microreactor
The PCAT device simulates the primary cooling circuit of the MARVEL reactor using electricity, allowing validation of its thermal-hydraulic behavior without the need for nuclear fuel. Tests confirmed that the natural circulation design, based on convection without mechanical components, is effective in maintaining heat flow and ensuring system stability.
On the other hand, the main objectives were to evaluate the accuracy of the RELAP5-3D software used in the MARVEL safety analysis. The data collected during the test campaign showed a strong correlation with the numerical predictions, which reinforces the reliability of the digital model for predicting reactor behavior in real scenarios.
During development, the team faced problems with the Stirling engines. Stirling engines initially contemplated for tertiary cooling. Vibrations and noise led to a redesign of the system to a more stable radiator-type solution. In addition, the use of liquid metals as coolant involved collaboration with Creative Engineers, specialists in the handling of these reactive materials.
Through these tests, it was confirmed that MARVEL can operate generating up to 100 kilowatts of thermal energy efficiently and safely. Although some higher-than-estimated heat losses were detected, this information will allow the final design to be adjusted. The success of the PCAT boosts confidence in the next stages of the project, which include submitting documentation to the Department of Energy and the future commissioning of the reactor.
With these results, the INL MARVEL team is in a position to move forward toward fabrication and assembly of the microreactor at the transient reactor test facility. Also, the findings will be shared with the scientific community to foster the development of compact nuclear systems in remote, industrial and homeland security applications.
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Source and photo: DOE
