EFDA-JET-PR(14)20

Neutron Streaming Through the JET Personnel Entrance Labyrinth

Neutron streaming through the personnel entrance labyrinth of the Joint European Torus (JET) Hall was evaluated. Monte Carlo calculations using the MCNP code were performed in order to predict neutron fluence and ambient dose equivalent along the labyrinth. The calculations were validated by comparison with measurements performed using thermoluminescence detectors. Simulations were performed for both D-D and D-T toroidal plasma discharge sources. Baseline calculations were performed for the "as-built" concrete composition. The sensitivity of the calculations on hydrogen and boron content in concrete was examined. The results of the study showed that neutron streaming through the labyrinth is independent of the initial energy of the plasma source and depends only on the labyrinth geometry and material configuration. The present work supports the operational radiation protection effort to minimize collective radiation dose to personnel at JET. Moreover it provides important information from JET experience that may assist in the optimization and validation of the radiation shielding design methodology used for ITER.
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EFDP14020 1.02 Mb