Editing Shippingport Light Water Breeder Reactor (section)

== Results and Significance ==

When the LWBR was shut down and its fuel discharged and analysed:

* Measurements confirmed that the reactor had '''produced more U-233 than it consumed''' — it had bred fuel, achieving a breeding ratio greater than 1.0.
* This made it one of very few reactors ever to achieve fuel breeding in a thermal neutron spectrum.
* It demonstrated conclusively that the thorium-uranium cycle could sustain itself in a practical reactor design.

The LWBR demonstration was publicly announced and the results published, but received relatively little public attention. The US government was at this point committed to the uranium-plutonium cycle, and the LWBR results were not leveraged into a follow-on programme.