NANTeL Chemistry and Water Treatment

Question 1

What is the primary purpose of maintaining proper pH levels in the Reactor Coolant System (RCS) of a PWR?

Accepted Answer

To minimize corrosion of reactor components

Answer

To increase heat transfer efficiency

Answer

To enhance neutron moderation

Answer

To prevent steam formation

Question 2

In a Pressurized Water Reactor (PWR), what chemical is dissolved in the reactor coolant to provide chemical shim reactivity control?

Accepted Answer

Boric acid

Answer

Sodium hydroxide

Answer

Lithium hydroxide

Answer

Hydrazine

Question 3

What is the purpose of adding lithium hydroxide (LiOH) to PWR reactor coolant chemistry?

Accepted Answer

To maintain alkaline pH and minimize corrosion

Answer

To absorb excess neutrons during power transients

Answer

To reduce dissolved oxygen concentration

Answer

To prevent crud deposition on fuel pins

Question 4

In nuclear plant chemistry, what is 'crud' and why is it operationally significant?

Accepted Answer

Corrosion products deposited on fuel assemblies that can become activated

Answer

Radioactive gases released through fuel cladding defects

Answer

Chemical byproducts formed when boric acid reacts with coolant

Answer

Dissolved minerals introduced by makeup water

Question 5

In a Boiling Water Reactor (BWR), what is the primary chemistry strategy used to mitigate Intergranular Stress Corrosion Cracking (IGSCC) of stainless steel piping?

Accepted Answer

Hydrogen Water Chemistry (HWC) to suppress dissolved oxygen

Answer

Boric acid injection into the feedwater

Answer

Lithium hydroxide additions to raise coolant pH

Answer

Periodic injection of zinc acetate only

Question 6

What is the primary function of hydrazine (N₂H₄) when used in nuclear plant secondary water chemistry?

Accepted Answer

To scavenge dissolved oxygen and prevent oxidative corrosion

Answer

To raise steam generator secondary-side pH above 9.5

Answer

To serve as a supplemental neutron absorber in the feedwater

Answer

To prevent mineral scaling on steam generator heat transfer surfaces

Question 7

What does the term 'Activity Transport' describe in nuclear plant chemistry operations?

Accepted Answer

Circulation of activated corrosion products through the reactor coolant system

Answer

Movement of radioactive material in NRC-approved shipping casks

Answer

Transfer of spent fuel assemblies from the reactor to the spent fuel pool

Answer

Migration of fission gases through defective fuel cladding