Radiation shielding design of the CFETR polarimeter interferometer and CO2 dispersion interferometer

Abstract A three-wave based laser polarimeter/interferometer and a CO 2 laser dispersion interferometer are used to determine the electron and current density profiles on a Chinese fusion engineering test reactor (CFETR). Radiation shielding is designed for the combination of polarimeter/interferometer and CO 2 dispersion interferometer. Furthermore, neutronics models of the two systems are developed based on the engineering-integrated design of CFETR polarimeter/interferometer and CO 2 dispersion interferometer and the major material components of CFETR. The polarimeter/interferometer and CO 2 dispersion interferometer’s neutron and photon transport simulations were performed using the Monte Carlo neutral transport code to determine the energy deposition and neutron energy spectrum of the optical mirrors. The energy depositions of the first mirrors on the polarimeter/interferometer are reduced by three orders with the whole shielding. Since the mirrors of CO 2 dispersion interferometer are very close to the diagnostic first wall, shielding space is limited and the CO 2 dispersion interferometer energy deposition is higher than that of the polarimeter/interferometer. The dose rate after shutdown 10 6 s in the back-drawer structure has been estimated to be 83 μ Sv h −1 when the radiation shield is filled in the diagnostic shielding modules, which is below the design threshold of 100 μ Sv h −1 . Radiation shielding design plays a key role in successfully applying polarimeter/interferometer and CO 2 dispersive interferometer in CFETR.