Radon measurements in the environmental monitoring programme at Nuclear Engineering Institute

The Nuclear Engineering Institute (IEN), situated in Cidade Universitária Island, has particle accelerator CV 28, a particle accelerator RDS-111. Research nuclear reactor Argonauta, a radioactive waste repository, besides chemical laboratories which carry out activities with radioactive materials. Due to the developed works, solid wastes, liquid effluents, gases and aerosols can be produced and released to the environment and the set of these facilities sign the source term. Taking into account the atmospheric way as the most critical exposure way for population, especially the critical group, radon levels, aerosols and gamma exposure must be monitored. Within this context, one of the objectives of the Environmental Monitoring Programme is to keep an ongoing record of radioactivity levels in institute environment, to detect eventual material release that would need corrective actions. Radon Laboratory in IEN has periodically carried out measurements of 222 Rn levels, a radioactive gas from 238U chain, within institute area in six points regarded as relevant for detection of material release. Along time the radon, has been measured, its levels has been kept within normal environmental levels, with no indication of accidental release