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Plutonium recovered from LWR spent fuel, while not weapons grade, can be used to produce nuclear weapons at all levels of sophistication, [25] though in simple designs it may produce only a fizzle yield. [26] Weapons made with reactor-grade plutonium would require special cooling to keep them in storage and ready for use. [27]
This method was used for forming the first nuclear weapon pits. More modern pits are produced by casting. Subcritical testing showed that wrought and cast plutonium performance is the same. [2] [3] As only the ε-δ transition occurs during cooling, casting Pu-Ga is easier than casting pure plutonium. [4]
Plutonium consisting of more than about 90% 239 Pu is called weapons-grade plutonium; plutonium from spent nuclear fuel from commercial power reactors generally contains at least 20% 240 Pu and is called reactor-grade plutonium. However, modern nuclear weapons use fusion boosting, which mitigates the predetonation problem; if the pit can ...
A dedicated reactor operating on very low burnup (hence minimal exposure of newly formed plutonium-239 to additional neutrons which causes it to be transformed to heavier isotopes of plutonium) is generally required to produce material suitable for use in efficient nuclear weapons. While "weapons-grade" plutonium is defined to contain at least ...
Weapons-grade plutonium is defined as containing no more than 7% 240 Pu; this is achieved by only exposing 238 U to neutron sources for short periods of time to minimize the 240 Pu produced. Plutonium is classified according to the percentage of the contaminant plutonium-240 that it contains: Supergrade 2–3%; Weapons grade 3–7%; Fuel grade ...
The $1.8 billion project will aid in stockpile stewardship, a program designed to ensure the safety and reliability of the nation's nuclear weapons without the use of underground explosive testing.
When used on fuel from commercial power reactors the plutonium extracted typically contains too much Pu-240 to be considered "weapons-grade" plutonium, ideal for use in a nuclear weapon. Nevertheless, highly reliable nuclear weapons can be built at all levels of technical sophistication using reactor-grade plutonium. [16]
SEOUL (Reuters) -North Korea has halted the nuclear reactor at its main atomic complex, probably to extract plutonium that could be used for weapons by reprocessing spent fuel rods, a South Korean ...