Sources Of Radiation Exposure From Nuclear Reactor Flashcards
What fuel sources are used for U.S. nuclear reactors?
U-235 and Pu-239
What fuel is used for US naval reactors?
High enriched U-235 (HEU)
What do control rods absorbed to maintain the fission cycle?
Neutrons.
What is the most common source of radiation exposure during reactors operations?
N-16
What is the source of most radiation exposure when the reactor is shutdown?
Co-60
What is water used for in nuclear reactors?
Reflector
Moderator
Coolant
Shielding
What is added to the water in the shields to minimize corrosion?
Potassium Chromate (K2CrO4)
How are types of radiation emitted from fission classified?
Penetrating radiation
Non-penetrating radiation
Penetration radiation
Can pass through the entire body causing ionizations and may escape the reactor.
What are some examples of penetrating radiation?
Neutrons & gammas
Non-penetrating Radiation
Cannot pass the entire body; usually stopped by layers of skin or clothing causing ionizations and will not escape the reactor core.
Examples of non-penetrating radiation
Fission fragments
What are the critical conditions of a nuclear reactor
*Sub-critical reactor
*Critical reactor
* Super-critical reactor
What is a sub-critical reactor condition?
When Neutrons produce are fewer than the neutrons in the pervious generation (Neutron losses greater than production)
Critical reactor condition
When the neutrons produce in one generation equal the neutrons in the pervious generation (neutrons losses equal production).
Super-critical reactor condition
When the neutrons produced in one generation exceed the neturons in the pervious generation.
What critical condition should all reactors go to start up?
Super Critical Condition
C=1=1
Sub <1
Super >1
The neutrons produced to production during each critical conditions.
What is the purpose of water in the reactor vessel?
It acts as a
* Reflector
* Coolant
* Moderator
* Shielding
What nuclide causes 80% of radiation exposure during reactor operations?
N-16
Where is the Primary shield located?
Surrounds the reactor vessel.
What shielding is made up of steel, lead and water?
Primary Shielding.
How is corrosion minimized in regards to the water in the primary shield?
It is treated with potassium chromate.
Why does the navy use HEU?
The reactors in the Navy are limited by size, power-out requirements, and constraints on refueling that commercial do not have
What is the secondary shield made up of?
Steel, Lead, Borated Polyethylene and, Virgin polyethylene, and NFO filled w/ water or fuel (only on subs).
