Oklo, the Two Billion Year Old Nuclear Reactor

Oklo, the Two Billion Year Old Nuclear Reactor

Assessment

Interactive Video

Science, Physics, Social Studies, Chemistry

11th Grade - University

Hard

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Scientists discovered that the Oklo mine in Gabon, Central Africa, had less Uranium-235 than expected, leading to the realization that it was the site of a natural nuclear reactor from 2 billion years ago. This reactor operated under specific conditions, with Uranium-235 and neutrons present, and groundwater acting as a moderator to control the reaction. The cycle of reaction and cooling continued for hundreds of thousands of years until the uranium was depleted, leaving behind evidence of this ancient natural phenomenon.

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5 questions

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1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What was the initial clue that led scientists to investigate the Oklo mine?

The presence of unusual minerals

A lower than expected concentration of Uranium-235

Strange geological formations

High levels of radiation

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

Which isotope of uranium is crucial for nuclear reactions due to its ability to release significant energy?

Uranium-235

Uranium-234

Uranium-236

Uranium-238

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What role did groundwater play in the natural nuclear reactor at Oklo?

It slowed down neutrons to sustain the reaction

It absorbed excess radiation

It accelerated the reaction

It provided additional uranium

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How did the natural nuclear reactor at Oklo prevent a runaway reaction?

By boiling off groundwater to stop the reaction

Through the natural decay of uranium

By using control rods

By releasing excess neutrons into the atmosphere

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What eventually caused the natural nuclear reactor at Oklo to stop operating?

The introduction of foreign elements

A geological shift

The depletion of Uranium-235

A sudden increase in temperature