Editing Molten Salt Reactor Experiment (section)

== Achievements ==

=== Uranium-233 Operation ===
In 1968, the MSRE became the first reactor in history to be operated on uranium-233 fuel. This was an historic milestone: U-233 is the fissile product of the thorium fuel cycle, and operating a reactor on it proved that the entire concept was technically sound. The achievement was publicly announced by Glenn Seaborg, then chairman of the Atomic Energy Commission and Nobel Prize laureate.

=== Materials Performance ===
Hastelloy-N performed excellently throughout the MSRE's operation, demonstrating that a practical structural material existed that could withstand prolonged exposure to hot, radioactive fluoride salt. This had been a key engineering question.

=== Online Fission Product Removal ===
The MSRE successfully demonstrated real-time removal of gaseous fission products from the circulating fuel salt — a critical feature of the LFTR concept that prevents the accumulation of xenon, a powerful neutron poison that can destabilise or even shut down a solid-fuel reactor (as in the Chernobyl accident, where xenon poisoning contributed to the sequence of events).

=== Safety Demonstration ===
The MSRE demonstrated the key passive safety features of molten salt reactors, including the strongly negative temperature coefficient of reactivity and the drain plug concept.