Measurement and calculation of doses in and around north-west labyrinth in TFTR test cell shielding for D-T operation

TFTR test cell has a major penetration that exists on the inner side of the north-west corner of the test cell wall. There is no known direct line of sight from the plasma source to the door. The biological doses were measured at various locations inside both the legs of the labyrinth, in addition to, scattered locations on outer segments of the labyrinth facing the TFTR D-T plasma. In addition, six sets of activation foil detectors were placed covering the south-to-north leg, labyrinth entrance, and west-to-east leg. The doses have been calculated using 3-D Monte Carlo code MCNP with ENDF/B-VI. The calculations reproduce the broad features of the measured data. However, we find significant differences in the calculations for a number of locations. The possible reasons for the differences are discussed.