Abstract: A 451P Ion Chamber Survey Meter was used to monitor the surrounding radiation environment of a mobile roof type X-ray flaw detection room while the industrial X-ray flaw detection machine running in the detection room. The results show that the monitoring values on both sides of the exposure chamber door exceed the standard values, while the remaining monitoring sites values (0.15—0.37 μGy/h) can meet the limit requirement of 2.5 μGy/h. The shield of the exposure chamber door was calculated accordingly with improvement suggestions proposed then. The monitoring values of the door after rectification meet the limit requirement. Estimation was also made to the potential annual effective doses for the workers and the public.

Key words: X-ray flaw detection machine, mobile roof type X-ray flaw detection room, environmental monitoring, radiation to public