Stainless steel welding is typically performed with a process called Tungsten Inert Gas (TIG). Most of the tungsten rods used in this process are alloyed with thorium to enhance the properties of the weld. This places the rods into the category of Technically Enhanced Naturally Occurring Radioactive Material (TENORM).
The process to prepare the rods for use includes cutting the rods into "tips", typically about an inch long. These tips are then sharpened to a point on a grinder. Although not licensed material, San Onofre has implemented measures to control the spread of this the small bits of weld rod created during the grinding process by having the welding group add ventilation and collection devices to the grinders used to sharpen the tips. We are preparing to formalize this process and are considering: assigning the responsibility to install and maintain the ventilation and collection equipment to the weld groups; have Industrial Hygiene check on the installation at some frequency; and have the welders deliver the filters and collectors to RP for disposal. We would like to do some informal bench marking and would appreciate your response to the following questions: Does your station control grinding tungsten tips? Yes/No Who implements controls inside the RCA? RP / Safety / Other Who implements controls inside the Restricted Area? Who implements controls outside the Restricted Area? How do you dispose of the grinding dust? John W. Scott, CRP San Onofre Nuclear Generating Station (949) 368-6222
