Palisades Nuclear Generating Station

Challenge: Palisades wanted to protect workers during inspections under the reactor head, inspections that required lifting the head without using the polar crane.  Their blankets had to be installed after the reactor head was in place, which was causing them high installation dose.  Additionally, their blankets were secured by strapping, which was resulting in gaps and streaming.

Solution: Together, NPO and Palisades devised a specialized track-mounted lead blanket trolley system that holds 40,000 pounds (18,200 kg) of lead, providing 1 inch (2.54 cm) lead sheet equivalent.  With this system, the shielding is installed prior to the head placement.  The track permits the shielding to be stacked on half of the lift structure/shield track.  Once the head is in place, the rest of the lifting structure and track can be installed.   The 10 foot (3 m) high shield panels,  comprised of two 5 foot (1.5 m) blankets using NPO’s integral hook system, are then rolled around the track, providing 360 degrees of shielding.

Results:  Palisades now incurs lower installation and project doses.  The new system provides them a factor of 7-8 dose reduction.

 back to Engineered ALARA Solutions