CALIBRATION OF SURVEY INSTRUMENTS

A. A licensee must calibrate the survey instruments used to show compliance with parts 4731.2000 to 4731.2950 and 4731.4400 to 4731.4527 before first use, intervals not to exceed 12 months, and following a repair that affects the calibration. A licensee must: (1) calibrate all scales with readings up to 1,000 millirems (10 mSv) per hour with a radiation source; (2) calibrate two separate readings on each scale or decade that will be used to show compliance; and (3) conspicuously note on the instrument the date of calibration. B. A licensee may not use survey instruments if the difference between the indicated exposure rate and the calculated exposure rate is more than 20 percent. C. A licensee must retain a record of each survey instrument calibration according to part 4731.4502 , subpart 2.