Radioactivation analysis of 14 MeV neutron generator facility

摘要

Institute for Plasma Research (IPR) is establishing an intense neutron generator facility. It is an accelerator-based 14 MeV neutron generator that produces 1012 neutrons per second. The neutron generator facility has various components that are made of different kinds of materials. It gets radio-activated due to the direct interaction of neutrons and secondary radiations. The radio activation of components has short term and long term effects in neutron generator operation and maintenance. The facility is built with concrete shielding. It will be operated at atmospheric pressure. The concrete walls and air in the hall also face neutron irradiation, which needs to be estimated for precautionary safety measures during maintenance. Long term operation of neutron generator can also affect the ground soil. The production of tritium in the soil can also become an issue for the general public health and can create a safety concern. Therefore, the simulation has been carried out to estimate the radio-activation of the neutron generator facility, which may impact neutron generator operation and maintenance. The estimation will also provide the level of radioactive waste generated due to the long term operation of the neutron generator. The operational licensing of the neutron generator is also required the estimation of radio-nuclide and dose rates after irradiation. The present work contains the neutron activation of neutron generators components that are present in the hall. The analysis is conducted for air activation, soil activation, concrete wall activation, and doors activation. The generation of ozone due to radiation interaction with air is also estimated to avoid ozone hazards during the maintenance. The simulation has been carried out using the Monte Carlo radiation transport tool and radionuclide inventory estimation tool FISPACT. Estimated results are compared with the regulatory limits. The analyses conclude that the facility is safe for long term operation.