Shielding

Section 346.250  Shielding a)         The radiation dose rate in areas that are normally occupied during operations of a panoramic irradiator may not exceed 0.02 millisievert (2 millirems) per hour at any location 30 centimeters or more from the wall of the room when the sources are exposed.  The dose rate shall be averaged over an area not to exceed 100 square centimeters having no linear dimensions greater than 20 cm.  Areas where the radiation dose rate exceeds 0.02 millisievert (2 millirems) per hour shall be locked, roped off or posted. b)         The radiation dose at 30 centimeters over the edge of the pool of a pool irradiator may not exceed 0.02 millisievert (2 millirems) per hour when the sources are in fully shielded position. c)         The radiation dose rate at 1 meter from the shield of a dry-source-storage panoramic irradiator when the source is shielded may not exceed 0.02 millisievert (2 millirems) per hour and at 5 centimeters from the shield may not exceed 0.2 millisievert (20 millirems) per hour.