US and UK naval reactors are fueled by uranium enriched to about 93% U-235. What grade is this?

US and UK naval reactors are fueled by uranium enriched to about 93% U-235. What grade is this?

• A. Low enriched uranium
• B. High enriched uranium
• C. Reactor grade uranium
• D. Weapon grade uranium

Answer: (D)

Enrichment level tells you how much U-235 is in the uranium and that drives what it’s used for. Natural uranium has about 0.7% U-235. Low-enriched uranium, used in most commercial reactors, is up to roughly a few percent. Above about 20% U-235 is called highly enriched uranium. When enrichment reaches around 90% U-235, it is described as weapon-grade uranium. Naval reactors need a very compact, long-life core, so using fuel with a very high fissile content makes the reactor size and refueling needs practical. Around 93% U-235 is the classic weapon-grade level, which is why that grade is labeled as weapon-grade uranium. The other terms fit different uses: low-enriched for typical power reactors, reactor-grade for fuel at lower enrichment used in many reactors, and highly enriched as a broader category that includes very high enrichments like this but doesn’t specify its suitability for weapons.

Enrichment level tells you how much U-235 is in the uranium and that drives what it’s used for. Natural uranium has about 0.7% U-235. Low-enriched uranium, used in most commercial reactors, is up to roughly a few percent. Above about 20% U-235 is called highly enriched uranium. When enrichment reaches around 90% U-235, it is described as weapon-grade uranium. Naval reactors need a very compact, long-life core, so using fuel with a very high fissile content makes the reactor size and refueling needs practical. Around 93% U-235 is the classic weapon-grade level, which is why that grade is labeled as weapon-grade uranium. The other terms fit different uses: low-enriched for typical power reactors, reactor-grade for fuel at lower enrichment used in many reactors, and highly enriched as a broader category that includes very high enrichments like this but doesn’t specify its suitability for weapons.