Sources Of Radiation Exposure From Nuclear Reactor

Question 1

What fuel sources are used for U.S. nuclear reactors?

Answer 1

U-235 and Pu-239

Question 2

What fuel is used for US naval reactors?

Answer 2

High enriched U-235 (HEU)

Question 3

What do control rods absorbed to maintain the fission cycle?

Answer 3

Neutrons.

Question 4

What is the most common source of radiation exposure during reactors operations?

Answer 4

N-16

Question 5

What is the source of most radiation exposure when the reactor is shutdown?

Answer 5

Co-60

Question 6

What is water used for in nuclear reactors?

Answer 6

Reflector
Moderator
Coolant
Shielding

Question 7

What is added to the water in the shields to minimize corrosion?

Answer 7

Potassium Chromate (K2CrO4)

Question 8

How are types of radiation emitted from fission classified?

Answer 8

Penetrating radiation

Non-penetrating radiation

Question 9

Penetration radiation

Answer 9

Can pass through the entire body causing ionizations and may escape the reactor.

Question 10

What are some examples of penetrating radiation?

Answer 10

Neutrons & gammas

Question 11

Non-penetrating Radiation

Answer 11

Cannot pass the entire body; usually stopped by layers of skin or clothing causing ionizations and will not escape the reactor core.

Question 12

Examples of non-penetrating radiation

Answer 12

Fission fragments

Question 13

What are the critical conditions of a nuclear reactor

Answer 13

*Sub-critical reactor
*Critical reactor
* Super-critical reactor

Question 14

What is a sub-critical reactor condition?

Answer 14

When Neutrons produce are fewer than the neutrons in the pervious generation (Neutron losses greater than production)

Question 15

Critical reactor condition

Answer 15

When the neutrons produce in one generation equal the neutrons in the pervious generation (neutrons losses equal production).

Question 16

Super-critical reactor condition

Answer 16

When the neutrons produced in one generation exceed the neturons in the pervious generation.

Question 17

What critical condition should all reactors go to start up?

Answer 17

Super Critical Condition

Question 18

C=1=1
Sub <1
Super >1

Answer 18

The neutrons produced to production during each critical conditions.

Question 19

What is the purpose of water in the reactor vessel?

Answer 19

It acts as a
* Reflector
* Coolant
* Moderator
* Shielding

Question 20

What nuclide causes 80% of radiation exposure during reactor operations?

Answer 20

N-16

Question 21

Where is the Primary shield located?

Answer 21

Surrounds the reactor vessel.

Question 22

What shielding is made up of steel, lead and water?

Answer 22

Primary Shielding.

Question 23

How is corrosion minimized in regards to the water in the primary shield?

Answer 23

It is treated with potassium chromate.

Question 24

Why does the navy use HEU?

Answer 24

The reactors in the Navy are limited by size, power-out requirements, and constraints on refueling that commercial do not have

Question 25

What is the secondary shield made up of?

Answer 25

Steel, Lead, Borated Polyethylene and, Virgin polyethylene, and NFO filled w/ water or fuel (only on subs).