ROBOTIC WALL SCRUBBER FOR NUCLEAR REACTOR WELLS AND FUEL STORAGE POOLS

DURING THE REFUELING OPERATIONS AT A NUCLEAR POWER PLANT, IT IS NECESSARY TO FLOOD LARGE CAVITIES ABOVE THE REACTOR PRESSURE VESSEL WITH WATER TO PROVIDE RADIATION SHIELDING. THE SPENT FUEL IS TRANSPORTED THROUGH THESE CAVITIES TO A TEMPORARY STORAGE POOL LOCATED NEAR THE REACTOR. OTHER CONTAMINATED INTERNAL REACTOR COMPONENTS ARE ALSO STORED WITHIN THESE CAVITIES DURING REFUELING. ONCE THE REFUELING OPERATION ARE COMPLETE, THE CAVITIES ARE DRAINED, AND THE REACTOR VESSEL IS REASSEMBLED. BECAUSE RADIOACTIVE PARTICLES BECOME SUSPENDED IN THE WATER AND ADHERE TO THE STAINLESS STEEL LININGS OF THE CAVITIES THEY MUST BE REMOVEDBEFORE THE LINING IS ALLOWED TO DRY IN ORDER TO PREVENT PARTICLES FROM BECOMING AIRBORNE CONTAMINATES. CLEANING THE LARGE SURFACE AREAS IS PERFORMED BY WORKERS WEARING PROTECTIVE CLOTHING WHO MUST CAREFULLY WIPE THE WALL SURFACES WITH CLEAN TOWELS. BOTH TOWELS AND WORKERS GARMENTS BECOME CONTAMINATED AND REQUIRE SPECIAL HALDLING. THIS TIME CONSUMING TASK CAN ADD SEVERAL DAYS TO A REFUELING OUTAGE. THE PRESENT PRACTICE NOT ONLY INCREASES THE COST OF THE OUTAGE IT ALSO EXPOSES WORKERS TO A HAZARDOUS RADIOACTIVE ENVIRONMENT AND CREATES LOW LEVEL WASTE MATERIALS. A RECENT STUDY BY EPRI RATED THE DEVELOPMENT OF A ROBOTIC SYSTEM TO CLEAN/SCRUB REACTOR WELLSAND FUEL STORAGE POOLS A TOP PRIORITY. IT IS PROPOSED TO DESIGN AN END-EFFECTOR (CLEANING HEAD) AND USE EXISTING ROBOTICS TECHNOLOGY AND RADIOACTIVE DETECTION DEVICES TO DEVELOP A CLEANING SYSTEM TO REDUCE WORKER EXPOSURE, CLEANING TIME, AND LOW LEVEL WASTE MATERIAL.