NANTeL Plant Systems Overview 3 — Questions and Answers
Question 1: What is the function of the Chemical and Volume Control System (CVCS) in a PWR?
- To control the concentration of boron in the primary coolant and maintain coolant inventory (Correct answer)
- To chemically treat the secondary feedwater
- To manage radioactive waste storage
- To control the air pressure inside containment
Correct answer: To control the concentration of boron in the primary coolant and maintain coolant inventory
The CVCS adjusts boron concentration for reactivity control, maintains primary coolant volume, and purifies coolant chemistry.
Question 2: During a station blackout, which system provides backup power to safety-related equipment?
- The turbine-driven feedwater pump only
- Emergency diesel generators (Correct answer)
- The high-pressure injection system
- The condensate storage tank
Correct answer: Emergency diesel generators
Emergency diesel generators automatically start and supply AC power to safety buses when normal offsite power is lost during a station blackout.
Question 3: What is the primary purpose of the spent fuel pool cooling system?
- To generate additional steam for the turbine
- To maintain adequate cooling of irradiated fuel assemblies removed from the reactor (Correct answer)
- To provide backup water supply for the ECCS
- To filter reactor coolant before it enters the primary loop
Correct answer: To maintain adequate cooling of irradiated fuel assemblies removed from the reactor
The spent fuel pool cooling system circulates water through heat exchangers to remove decay heat from recently discharged fuel assemblies.
Question 4: In nuclear plant operations, what does the term 'defense-in-depth' refer to?
- The physical security perimeter around the plant site
- Multiple independent barriers and safety systems to prevent radioactive release (Correct answer)
- The depth at which reactor coolant pipes are buried underground
- The redundancy of the plant's electrical switchgear
Correct answer: Multiple independent barriers and safety systems to prevent radioactive release
Defense-in-depth uses multiple independent safety layers—fuel cladding, primary pressure boundary, and containment—along with diverse safety systems to prevent accidents.
Question 5: What is the function of reactor coolant pumps (RCPs) in a PWR?
- To inject emergency coolant during a LOCA
- To circulate primary coolant through the reactor core and steam generators (Correct answer)
- To pressurize the primary system above saturation temperature
- To pump feedwater from the condenser to the steam generators
Correct answer: To circulate primary coolant through the reactor core and steam generators
RCPs maintain forced circulation of primary coolant, ensuring efficient heat transfer from the reactor core to the steam generators.
Question 6: Which system manages the collection, processing, and disposal of liquid radioactive waste at a nuclear plant?
- The demineralized water system
- The Liquid Radwaste System (Correct answer)
- The containment spray system
- The auxiliary feedwater system
Correct answer: The Liquid Radwaste System
The Liquid Radwaste System collects, monitors, processes, and releases or disposes of liquid streams containing radioactive contamination.
Question 7: What is the primary heat sink for the secondary cycle in most nuclear power plants?
- The reactor core itself
- The condenser, which transfers heat to a cooling water source (Correct answer)
- The pressurizer relief tank
- The auxiliary building ventilation system
Correct answer: The condenser, which transfers heat to a cooling water source
The condenser removes heat from exhaust steam after it passes through the turbine, using river, lake, ocean, or cooling tower water as the ultimate heat sink.
NANTeL Plant Systems Overview 3
What is the function of the Chemical and Volume Control System (CVCS) in a PWR?