RICHLAND, Wash. – EM’s Office of River Protection (ORP) removed a 30-ton stainless steel vessel to make way for a new one to fulfill a critical role in verifying design and performance of the Pretreatment Facility at the Waste Treatment and Immobilization Plant (WTP).

   The new 35-foot-high vessel, a full-size prototype, is scheduled for delivery to ORP this summer. WTP employees are developing a test plan for it to support requirements verification. Test platform commissioning is expected to begin late this year.

   Testing of the old 18-foot-tall vessel ended in December. Workers removed the vessel by connecting it to a crane and lifting it out of a skylight in the laboratory’s roof.

   The old vessel allowed WTP employees to demonstrate that pulse jet mixers planned for use in pretreatment would work with a range of radioactive waste mixes as anticipated.

   “Our recently completed tests demonstrated we can consistently and reliably control these mixers,” Pretreatment Area Project Manager Felice Presti said. “We’re looking forward to conducting the full-scale testing. Our goal is to construct a safe, effective facility to help treat waste and, ultimately, protect the Columbia River and this community from Hanford waste.”

   The old vessel enabled ORP to capture data on how the computer controls outside the vessel worked to operate mixers inside the vessel under a variety of tank levels using simulated waste with a low amount of solids. Later tests showed how the mixers performed under a variety of slurry and tank-level conditions, from low to high amounts of solids, using simulants. 

   In 2012, the testing protocol for the mixers expanded to include studies with full-scale vessels. Previous plans relied on computational models and testing in smaller vessels.

   Used in nuclear applications for mixing radioactive liquids, slurries, and sludge for more than 40 years, the mixers contain no moving parts and mix waste by expelling it with compressed air. They are refilled with waste by applying a vacuum pressure.  

   Vessel testing occurs at ORP’s Full-Scale Vessel Test Facility, which houses testing programs for Hanford site projects to help to ensure progress while reducing risk to workers and our environment.

   WTP will be the world’s largest radioactive nuclear waste vitrification facility and is being designed and constructed by ORP contractor Bechtel National Inc. When complete, it will vitrify most of the 56 million gallons of the country’s most complex nuclear waste currently stored in tanks on the Hanford site.

   The largest of the four major WTP nuclear facilities, the Pretreatment Facility’s interior waste feed receipt vessels will receive waste pumped from the Hanford tanks via underground pipes. In the first pretreatment phase, the waste will be concentrated using an evaporation process. Solids will be filtered out, and the remaining soluble, highly radioactive isotopes will be removed using an ion-exchange process.