|
*What is a light water reactor?
A light water reactor uses normal water as the moderator that cools the reactor and produces the steam that powers the
turbines
Light water reactors require uranium to be enriched from 2.5-3.5% for the reaction to be contained in a nuclear reactor
*Heavy water reactors
Used in Canada
Uses "heavy water"
Water that instead of using H1 molecules uses deuterium (an isotope of hydrogen that is heavier - mass 2)
Instead of H2O, heavy water has a formula of D2O (D stands for deuterium)
Does not require uranium to be enriched
Uranium can be implemented into the reactor system as ore
Deuterium isotope counters the need for neutrons
*Definitions to understand
Critical mass - amount of material required to start a reaction
Fissile content - amount of content in an object that contributes to that item reaching a critical mass for a reaction
Moderators - Components that slow down neutrons, allowing them to start a nuclear reaction (criticality)
Cross-section - probability that a reaction will occur when particles meet
*Differences in light water and heavy water reactors
Heavy water is a poorer moderator than light water (it has a lower absorption cross-section)
Heavy water needs fewer radioactive particles (neutrons) to start a chain reaction
Therefore, the unrefined ore of regular uranium can be used
Light water is a better moderator
More enriched uranium (such as U-235) must be used
This requires a difficult enrichment program to extract U-235 from regular uranium
* Why does this matter in the political world?
Each nuclear reactor type has its own risk of creating an atomic bomb
Heavy water reactors increase nuclear proliferation, meaning, if countries have heavy water reactors, they will require
large amounts of uranium to keep them running
But, to make an atomic bomb, uranium must be enriched to over 90%
Heavy water reactors also produce more plutonium waste - which can also be used to make atomic bombs
Why light water reactors are dangerous:
Light water reactors require enriched uranium to reach critical mass
Therefore, those that have them must enrich their uranium (thus providing the infrastructure not only to enrich to 3%
but also to 90% and potential for atomic bombs)
The choice:
Have heavy water reactors that require large amounts of uranium and produce plutonium waste (material for bombs)
Have light water reactors that require enriched uranium (process for bombs)
* Foreign policy
The US would like to prevent nations like formerly-Saddam-controlled Iraq, Iran, North Korea and others to have nuclear
power at all
This eliminates even the option of having any way of making an atomic bomb, either material or the enrichment process
Current events:
Light-water reactors in Iran (decreases nuclear proliferation but still risky because of the easy way to get weapons-grade
uranium)
North Korea uses a Magnox reactor, similar to heavy water reactors, that allows them to have power but produces much plutonium
waste (US is trying to keep North Korea from getting the technology to enrich the uranium and plutonium to weapons grade)
|
