Which barrier is the third fission product barrier?

Which barrier is the third fission product barrier?

• A. Fuel pellet and cladding
• B. RCS pressure boundary
• C. Containment
• D. Shielding

Answer: (C)

Fission products are kept behind a sequence of barriers to prevent release to the environment. The first barrier is the fuel itself—the fuel pellets and their metal cladding retain most fission products under normal operation and during small incidents. The second barrier is the reactor coolant system pressure boundary—the piping and components that hold the primary coolant, preventing fission products that may escape the fuel from spreading through the plant. The third barrier is containment—the strong structure around the reactor and primary system designed to stop any escaped material from reaching the outside environment. Shielding’s role is to reduce radiation exposure to personnel, not to confine released fission products, so it isn’t considered the barrier for containment.

Fission products are kept behind a sequence of barriers to prevent release to the environment. The first barrier is the fuel itself—the fuel pellets and their metal cladding retain most fission products under normal operation and during small incidents. The second barrier is the reactor coolant system pressure boundary—the piping and components that hold the primary coolant, preventing fission products that may escape the fuel from spreading through the plant. The third barrier is containment—the strong structure around the reactor and primary system designed to stop any escaped material from reaching the outside environment. Shielding’s role is to reduce radiation exposure to personnel, not to confine released fission products, so it isn’t considered the barrier for containment.