RICHLAND, Wash. – An expert panel met this month to discuss the integrity of double-shell tank AY-102 on behalf of EM’s Office of River Protection (ORP).  

   The panel reviewed the recent level rise in the AY-102 annulus and found no evidence of waste leaking from the secondary, or outer, shell of the tank. The tank was discovered to be leaking from its inner shell in 2012 into the annulus between the two tank walls.  

   Commissioned in 2015, the Tank Integrity Expert Panel evolved from past expert panels and includes participants from other DOE sites and national laboratories, industry, and academia.

“Working with outside experts is key to improving our tank integrity program, which is an important aspect of the Washington River Protection Solutions (WRPS) mission, in that it can help extend the life of our tanks and better understand potential degradation,” said Dan Baide, tank farm projects and integrity engineering manager. WRPS is the ORP tank farms contractor at the Hanford Site.

   The panel spent two days at DOE’s Pacific Northwest National Laboratory being briefed by subject-matter experts in WRPS’ Tank and Pipeline Integrity organization. Topics included the impact of sluicing on the leak in the primary shell of AY-102, chemistry control, corrosion testing, extent of condition, and different modes and methods used for testing and inspecting Hanford’s tanks.

   “This gathering is part of our ongoing effort to better understand what caused the leak in Tank AY-102 and how to ensure it doesn’t occur again in the remaining 27 double-shell tanks,” said Baide.

   The panelists recommended WRPS initiate a project to visually inspect the air slots in the refractory beneath the primary tank shell near the suspected site of the leak. They also advised that WRPS install a corrosion probe in the tank annulus; conduct non-destructive evaluation of the secondary shell to look for wall thinning; evaluate technologies to determine if water is present under the tank; and employ guided wave technology, a long-range ultrasonic testing inspection technique.

   WRPS’s Tank and Pipeline Integrity program is essential to the tank operations mission. The program monitors tank integrity by examining waste chemistry, corrosion rates, storage histories, and changing conditions. Tank inspections are performed through ultrasonic testing and visual inspections. These inspections provide important information and can alert engineers to any potential issues regarding the structural integrity of the underground waste storage tanks.