Published on November 8, 2007
Slide1: The U.S. Department of Energy’s Office of River Protection Lessons Learned from Waste Transfer Line Modifications Brandon Williamson, Facility Representative Tank Farm Operations The ORP Mission : The ORP Mission Hanford’s 177 Waste Tanks 149 single-shell tanks Built from 1943-1964 Tanks range from 37 to 50 feet tall and are 20 to 75 feet in diameter 28 double-shell tanks Built from 1968-1986 Tanks are 55 feet tall and 75 feet in diameter Retrieve and treat Hanford’s tank waste and close the tank farms to protect the Columbia River Overview: Overview A TSR Violation Occurred During a Waste Transfer Through Excavated Piping (an Abnormal Configuration) Lessons Learned Strive For Clear Safety Basis / Procedures Language Definitions must be clear Terms must match between procedures and safety basis Operations Personnel Must Be Trained To Procedures Clear understanding of critical definitions Clear understanding of physical components Finish The Job Timely manner Return to usual configuration Waste Transfer Lines: Waste Transfer Lines Transfers of high level waste from tank to tank are done through buried encased steel piping (transfer lines) To prevent any leakage from becoming an aerosol that could harm on site personnel To reduce the radiological dose rate Two types of waste transfer lines Supernate – liquid floating above the solids in a tank Slurry – insoluble material suspended in solution Slurry transfer lines had Clean Out Boxes (COBs) along the route to provide a means to unplug a line. COBs had to be removed by 6-30-05 for the line to be RCRA compliant. Clean Out Box (COB): Clean Out Box (COB) Clean Out Box (COB): Clean Out Box (COB) COB Removal: COB Removal TSR Violation of March 2005: TSR Violation of March 2005 Exposed Active Transfer Pipe: Exposed Active Transfer Pipe AC 5.11 requires covers over unburied sections of encased WASTE transfer piping when this piping is PHYSICALLY CONNECTED to an ACTIVE WASTE transfer pump not under administrative lock. The purpose is to prevent a transfer line leak from becoming a spray leak that sends radiological and toxic material airborne where it could harm the co-located worker. I notified the Shift Office and the transfer was shut down Why wasn’t this found prior to the transfer? Pretty obvious right? Not exactly, and here’s why… The Causes: The Causes Poor definition of terms in the Admin Controls/Procedures Inadequate training of operations personnel for the task they were assigned Slow progress of field work that forced the need to transfer through lines in various stages of modification. The Causes (Cont.): The Causes (Cont.) Poor definition of terms in the ACs/procedures The AC requirement was written in terms of “unburied” piping. The term “unburied” was interpreted and flowed into procedures as “exposed”. The AC 5.11.2.a.8 requirement reads as follows: “VERIFY that covers are in place over unburied (i.e., excavated) sections of encased WASTE transfer piping when this piping is PHYSICALLY CONNECTED to an ACTIVE WASTE transfer pump not under administrative lock, ...” A literal interpretation of the term “unburied” was applied by Operations where “unburied piping” is equivalent to “exposed piping.” The condition where a thin layer of soil remained over the piping was interpreted by operations to meet the definition of “buried”. Transfer Spray Covers: Transfer Spray Covers COBs AW 5&6 4-22-05 The Causes (Cont.): The Causes (Cont.) Inadequate training for the operations personnel Performed walk down and saw the excavation, no response Were not conversant on what an adequate transfer cover is Did not recognize that seeing foam means a pipe is exposed Slow progress of field work Removal of the AW COBs began in December of 2003 and should have been completed by July of 2004. The TSR violation was found on March 22, 2005. The need to use the transfer lines to perform our mission in the meantime opened the door to problems. The Corrective Actions: The Corrective Actions Clarified the Admin Control implementing procedure as to what constituted “unburied”- removal of 12 inches of covering soil. Revised transfer procedure template to change the word “exposed” to “unburied” and added wording to look for encasement foam. Operations personnel trained to new procedures. Conclusion : Conclusion Operating outside of normal conditions can create unforeseen and potentially significant issues. To minimize the chance for those issues to arise, it is essential to use precise language in the safety basis, and that the wording in operations procedures is consistent with that precise language. Operators must be trained to those procedures. Lastly, a quick return to normal configuration can prevent, or at least minimize the time of exposure to those potential issues. Any questions or comments?