Radioactive waste: Plutonium
The following is based on the limited open source materials on Atomic Alchemy’s VIPR reactor from the cancelled Meitner-1 project.
Section 4.5.2.1 of Chapter 4 – Reactor Description ATOMIC ALCHEMY INC. states:
effective delayed neutron fraction of the core is predicted to decrease from 0.66% to 0.60% as U-235 is depleted and Pu-239 is produced
Plutonium (Pu-239) is a byproduct of fission in a Low-Enriched Uranium (LEU) reactor. From the Wikipedia article on Pu-239:
A fission of an atom of uranium-235 (with 0.720% abundance) in a nuclear reactor produces two to three neutrons, and these neutrons can be absorbed by uranium-238 (with 99.3% abundance) to produce plutonium-239 and other isotopes. Plutonium-239 will also absorb neutrons and fission along with the uranium-235 in a reactor.
Plutonium-239 has a half-life of 24,110 years.
LEU contains a low concentration of enriched (U-235) uranium, which is consumed in a light-water reactor such as Atomic Alchemy’s VIPR.
How much Pu-239 will be produced as an output product by the Groves reactor?
This will likely depend on a variety of factors, including:
- The mass quantity of U-235 processed in the reactor
- The rate of fission
- The presence of U-238 present in the fuel, which absorbs neutrons to become Pu-239
Plutonium-239 is much more highly reactive than Uranium, making it an attractive choice for reactor fuel as well as nuclear weapons.
Pu-239 can also be consumed as fuel in the same reactor, so it can have a complicated answer. This is why I would ask “as an output product”. Does the reactor attempt to burn up the Pu-239, as a CANDU reactor does, intended for peaceful purposes? Or is the Pu-239 being harvested and sent offsite for other purposes, or as an incredibly dangerous, extremely long-lived waste product?
Where is the Pu-239 sent, and how is it used?
One must wonder, if this is part of the “space applications, and national security needs” in Oklo’s recent response to our concerns?