Determination of absorbed and effective dose from natural background radiation around a nuclear research facility

Abstract

Problem statement: This study presents result of outdoor absorbed dose rate and estimated effective dose from the naturally occurring radionuclides 232Th and 238U series 40K, around a Nuclear Research Reactor at the Centre for Energy Research and Training (CERT), Zaria, Nigeria. Approach: A high-resolution in situ γ-ray spectrometry was used to carry out the study. CERT houses a 30Kw Research Reactor and other neutron and gamma sources for Research and Training. Results: The values of absorbed dose rate in air for 232Th, 238U and 40K range from 8.2 ± 2.5-24.5 ± 3.6 nGy h -1, 1.9 ± 1.2-4.6 ± 2.5 nGy h -1 and 12.2 ± 5-38 ± 6.7n Gy h -1 respectively. The estimated total annual effective dose outdoor for the sites range from 27.3-79.9 μSv y -1.Conclusions: This showed that radiation exposure level for the public is lower than the recommended value of 1 mSv y -1.Hence, the extensive usage of radioactive materials within and around CERT does not appear to have any impact on the radiation burden of the environment. © 2010 Science Publications.