Preliminary studies for the PDX tokamak radiation shield design

Shielding calculations have been done to arrive at a preliminary radiation shield design for the Poloidal Diverter Experiment (PDX) tokamak at PPPL. The PDX, which will be used to study plasma impurities in tokamaks, may generate up to 1018 2.5-MeV neutrons per year from D--D reactions and 5 x 1015 14-MeV neutrons per year from D--T reactions. It was determined that shielding doors and a shielding roof must be added to the existing .813-m (32-in.) heavy (i.e., high density) concrete walls to reduce radiation doses to the control room adjacent to PDX and to the site boundary 150 m away to acceptable levels. A .381-m (15-in.) thick roof composed of borated water (5000 ppM) contained in steel cans was recommended. Two doors leading to the control room should be .305 m (1 ft) of polyethylene or water-filled cans backed by 5.08 cm (2 in.) of steel or lead