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Why is it so difficult for Iran to build nuclear weapons today, if the US could build them in the 40’s?

Sarah Jenkins
Sarah Jenkins
Lead Content Curator · Jan 18, 2026 · Updated Apr 13, 2026

[The Manhattan Project](_URL_2_) was a tremendous project. It [ grew to employ more than 130,000 people and cost nearly US$2 billion (about $26 billion in 2015[1] dollars). Over 90% of the cost was for building factories and producing the fissile materials, with less than 10% for development and …

109
Words

1 min
Read Time

#98
of 500 in Science

+51%
vs Category Avg

The Short Answer

[The Manhattan Project](_URL_2_) was a tremendous project. It [ grew to employ more than 130,000 people and cost nearly US$2 billion (about $26 billion in 2015[1] dollars). Over 90% of the cost was for building factories and producing the fissile materials, with less than 10% for development and production of the weapons. Research and production took place at more than 30 sites across the United States, the United Kingdom and Canada.](_URL_2_) Sanctions have been put in place by other countries to prevent Iran from building atomic bombs. [Enriched uranium](_URL_0_) is needed. Iran has been producing this but not enough yet. Iran has just agreed to [reduce its current stockpile](_URL_1_) of enriched uranium.

Analysis

Key Concepts: Iran, project, cost

This explanation focuses on iran, project, cost and spans 109 words across 7 sentences. At 51% above the average Science explanation (72 words), this is one of the more thorough answers in this category, reflecting the complexity of the underlying question.

What This Answer Covers

The explanation opens with: “[The Manhattan Project](_URL_2_) was a tremendous project.” It then elaborates by presenting a contrasting perspective, ultimately building toward a complete picture across 7 connected points.

How This Compares in Science

Ranked #98 of 500 Science questions by answer depth (top 20%). This places it in the comprehensive tier — the top quarter of most thoroughly answered questions. Questions at this depth typically involve multi-faceted topics requiring nuanced explanation.

Frequently Asked Questions

Is there a simple explanation for why it so difficult for iran to build nuclear weapons today, if the us could build them in the 40's?

[The Manhattan Project](_URL_2_) was a tremendous project. It [ grew to employ more than 130,000 people and cost nearly US$2 billion (about $26 billion in 2015[1] dollars). Over 90% of the cost was for building factories and producing the fissile…

How detailed is this explanation compared to similar Science questions?

This is one of the most thorough answer at 109 words, ranked #98 of 500 Science questions by depth. The key concepts covered are iran, project, cost.

What approach does this answer take to explain it so difficult for iran to build nuclear weapons today, if ?

The explanation uses contrasting perspectives and scientific references across 109 words. It is categorized under Science and addresses the question through 2 analytical lenses.