Physics Is Phun!

Question 1

3 key concepts to understanding the operation of a Pressurized Water Reactor

Answer 1

1. Reactivity
2. Reactor stability
3. Plant stability

Question 2

In terms of a Pressurized Water Reactor (PWR), REACTIVITY is

Answer 2

How the conditions inside the reactor affect the fission chain reaction

Question 3

In terms of a Pressurized Water Reactor (PWR), REACTOR STABILITY is

Answer 3

The feedback mechanisms that hold it steady

Question 4

In terms of a Pressurized Water Reactor (PWR), PLANT STABILITY is

Answer 4

What happens when you connect your reactor to the rest of the plant (and beyond)

Question 5

What determines the element’s chemical behavior

Answer 5

The number of electrons and how they are arranged

Question 6

The neutron itself won’t be carrying a lot of energy but it will release energy when

Answer 6

It joins with the nucleus

Question 7

If a neutron happens to encounter a U-235 and is traveling ______________ , it’s then very likely that fission will occur

Answer 7

Slowly enough to be captured

Question 8

Slow neutrons are sometimes called “thermal” neutrons. This is because

Answer 8

They will be traveling at the same speed as the atoms of the material around them, so they are called “in thermal equilibrium” with it.

Question 9

The process of slowing-down neutrons: it’s called ________________, and we call the material in which the neutrons slow-down a _________________

Answer 9

1. Moderation
2. Moderator

Question 10

An excellent way to slow down fast neutrons is to

Answer 10

Let them bounce around in some material, giving up a bit of their energy (speed) with each collision.

Question 11

In a Pressurized Water Reactor (PWR) _________________ is used as the moderator

Answer 11

Water

Question 12

More energy is lost in each collision if the atoms that the neutron collide with are a familiar size (mass) to the neutron themselves. The _________________________ being individual protons, make water and effective moderator

Answer 12

Hydrogen atoms in water molecules

Question 13

One of the most frequent errors that people make when they talk about nuclear reactors:

Answer 13

They describe the controls rods as moderating the reaction. To a reactor operator, a MODERATOR is what makes your REACTOR RUN.

Question 14

U-238 it is pretty good at capturing neutrons as they

Answer 14

Slow down through intermediate speeds (between fast and slow).

Question 15

Fast neutrons can be produced in the fuel, will escape the fuel into the moderator, where they will then

Answer 15

Slow down before bouncing back into the fuel, —> finding a fresh U-235 atom and, —> causing another fission. This is the CHAIN REACTION.

Question 16

Neutrons bounce around at random in the moderator so sometimes fall back into the fuel before they’ve sufficiently slowed down. If that happens,

Answer 16

There’s a good chance that they are going to get captured by a U-238 atom and so be lost in the reaction.

Question 17

Neutrons are lost in other ways. Some of them are

Answer 17

1. Captured by hydrogen-1 nuclei in the water to make hydrogen-2 (deuterium)
2. Captured by the engineering materials, usually metals
3. Leak out of the edges of the reactor