Which design principle helps prevent suction entrapment by the reactor coolant pump?

Which design principle helps prevent suction entrapment by the reactor coolant pump?

• A. Increasing pipe diameter
• B. Ensuring adequate net positive suction head and proper venting
• C. Using a single small suction line
• D. Raising coolant temperature

Answer: (B)

The important idea is guaranteeing enough pressure on the pump’s suction side to avoid creating a vacuum that could pull in a person or object. This is achieved by ensuring adequate Net Positive Suction Head (NPSH) and providing proper venting. Adequate NPSH means there’s enough pressure head at the suction to overcome the pump’s requirements, even under varying conditions, so the fluid stays in contact with the pump without cavitation or rapid pressure drop. Proper venting lets trapped air escape, preventing air pockets and vacuum formation that could intensify suction at the intake. Other options don’t address the pressure balance on the suction side. Simply increasing pipe diameter doesn’t guarantee sufficient suction pressure. Using a single small suction line can actually worsen suction effects, and raising coolant temperature doesn’t directly fix the suction head or venting issues.

The important idea is guaranteeing enough pressure on the pump’s suction side to avoid creating a vacuum that could pull in a person or object. This is achieved by ensuring adequate Net Positive Suction Head (NPSH) and providing proper venting. Adequate NPSH means there’s enough pressure head at the suction to overcome the pump’s requirements, even under varying conditions, so the fluid stays in contact with the pump without cavitation or rapid pressure drop. Proper venting lets trapped air escape, preventing air pockets and vacuum formation that could intensify suction at the intake.

Other options don’t address the pressure balance on the suction side. Simply increasing pipe diameter doesn’t guarantee sufficient suction pressure. Using a single small suction line can actually worsen suction effects, and raising coolant temperature doesn’t directly fix the suction head or venting issues.