uranium 238
C1Scientific/Technical
Definition
Meaning
A specific, naturally occurring isotope of uranium with atomic number 92 and mass number 238; the most abundant isotope of uranium.
In extended use, it refers to the material used as a fertile material in the production of plutonium-239 for nuclear weapons and reactors, and historically as a 'depleted' (non-fissile) heavy metal for armor-penetrating munitions and ballast.
Linguistics
Semantic Notes
The term is a technical compound. In non-technical contexts, people often refer simply to 'uranium', but 'uranium-238' specifies the isotope that is not fissile (with slow neutrons) and makes up over 99% of natural uranium.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or spelling differences. Spelling conventions for numbers follow the regional norms (e.g., no difference).
Connotations
Identical technical connotations. The general public may associate it more strongly with nuclear power or weapons technology.
Frequency
Exclusively used in scientific, technical, military, and historical contexts in both varieties. Virtually non-existent in everyday conversation.
Vocabulary
Collocations
Grammar
Valency Patterns
Uranium-238 [verb e.g., decays, is used, constitutes]Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None specific. Possibly referenced in phrases like 'the 238 workhorse' (in nuclear engineering contexts).”
Usage
Context Usage
Business
Used in industries related to nuclear energy, mining, and military hardware manufacturing.
Academic
Core term in nuclear physics, chemistry, geology, and engineering.
Everyday
Extremely rare. Might appear in news about nuclear power, weapons, or depleted uranium munitions.
Technical
Primary usage. Precise term in nuclear science, isotope geology (for dating), and radiation shielding.
Examples
By Part of Speech
verb
British English
- The sample was uranium-238 dated.
- They are attempting to uranium-238 separate the isotopes.
American English
- The reactor can uranium-238 breed plutonium.
- The lab will uranium-238 analyze the ore.
adverb
British English
- The material behaved uranium-238 rich.
- It decayed more uranium-238 like.
American English
- The sample tested uranium-238 heavy.
- It reacted uranium-238 typically.
adjective
British English
- The uranium-238 component is stable.
- A uranium-238 enrichment facility.
American English
- Uranium-238 contamination was minimal.
- The uranium-238 decay chain is long.
Examples
By CEFR Level
- Uranium is a metal. Uranium-238 is one type.
- Most natural uranium is uranium-238.
- Uranium-238 is not easily split to produce nuclear energy, unlike uranium-235.
- Geologists use the decay rate of uranium-238 to lead-206 to date ancient rocks with remarkable precision.
Learning
Memory Aids
Mnemonic
Think: Uranium's 'common one' (238 is the most common atomic mass) or 'Two-three-eight, the isotope that's great for making plutonium weight.'
Conceptual Metaphor
A FOUNDATION/SEED (fertile material that transforms into other elements); a HEAVYWEIGHT (due to its density and use in munitions).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating as just 'уран'. The number is essential for technical accuracy ('уран-238').
Common Mistakes
- Pronouncing '238' as 'two hundred thirty-eight' instead of 'two-thirty-eight'. Using 'uranium-238' interchangeably with 'enriched uranium' (which is enriched in U-235).
Practice
Quiz
What is a primary use of depleted uranium-238?
FAQ
Frequently Asked Questions
Yes, it is radioactive but with a very long half-life (about 4.5 billion years), so its radioactivity is relatively weak compared to many other isotopes.
Not directly as a fissile fuel in standard light-water reactors. However, it is a 'fertile' material, meaning it can absorb neutrons and transmute into plutonium-239, which is fissile.
Uranium-238 is the specific isotope. 'Depleted uranium' (DU) primarily refers to the material left after the more fissile U-235 is removed (enriched) from natural uranium; it is composed mainly of U-238 and is denser, used for armor and ballast.
Due to its very long and consistent half-life decaying into lead-206, scientists can measure the ratio of remaining U-238 to accumulated Pb-206 to calculate the age of rocks and minerals over billions of years.