The original reactor built in 1942 was just "barely" critical because the natural uranium that was used contained less than 1% of the fissionable isotope U-235 (half-life 713 million years). What if, in 1942, the Earth had been 9 billion years old instead of 4.5 billion years old? Would this reactor have reached critical stage with natural uranium? Why?

A. No. The increased age of the Earth would mean that there would be a much smaller percentage of U-235, thus not enough for the reactor to reach critical stage.
B. No. The age of the Earth has nothing to do with the reactor reaching critical stage with U-235.
C. No. 1% of the fissionable isotope U-235 is insufficient for the reactor to reach critical stage no matter what the age of the Earth.
D. Yes. If the Earth had been twice as old there would have then been twice as much fissionable U-235 present and the reactor would have reached critical stage.


Answer: A

Environmental & Atmospheric Sciences

You might also like to view...

The most common mafic volcanic rock is ________.

A. rhyolite B. tuff C. basalt D. obsidian E. andesite

Environmental & Atmospheric Sciences

________ is the angle of inclination of the surface of a rock unit measured from a horizontal plane

A) Dip B) Faulting C) Strike D) Plunge

Environmental & Atmospheric Sciences

Zonal flow wind-flow patterns are associated with

a. north-to-south flows. b. south-to-north flows. c. east-to-west flows.. d. west-to-east flows. e. random directional flows.

Environmental & Atmospheric Sciences

A second-growth forest is a(n) ____.

A. old-growth forest with lots of new seedlings B. old growth forest with recent regeneration C. forest resulting from secondary succession D. old growth forest that has been cut down with only weeds remaining E. forest containing only one or two species of trees that are all of the same age

Environmental & Atmospheric Sciences