Shielding calculations for the Tokamak Fusion Test Reactor neutral beam injectors

Two-dimensional discrete-ordinates calculations have been performed to determine the location and thickness of concrete shielding around the Tokamak Fusion Test Reactor neutral beam injectors. Two sets of calculations were performed, one to determine the dose equivalent rate on the roof and wall of the test cell building when no injectors are present, and one to determine the contribution to the dose equivalent rate at these locations from radiation streaming through the injection duct. Shielding the side and rear of the neutral beam injector with 0.305 and 0.61 m of concrete, respectively, and lining the inside of the test cell wall with an additional layer of concrete having a thickness of 0.305 m and a height above the axis of deuteron injection of 3.10 m is sufficient to maintain the biological dose equivalent rate outside the test cell to approx. 1 mrem/D-T pulse