Three aluminum pipes of 2-7/16″ internal diameter extend from approximately 18″ below the pool surface to grid box positions on the periphery of the core. These pipes draw sample bottles made of polyethylene down and position them approximately at the center line of the fuel. Two sample containers can be loaded in each tube. The addition of a second sample bottle, however, causes the natural rotation of the first bottle to stop. Thermal neutron fluxes in these positions are approximately 10^13 n/cm2-s.
