COMPARISON OF OXALIC ACID CLEANING RESULTS AT SRS AND HANFORD AND THE IMPACT ON ENHANCED CHEMICAL CLEANING DEPLOYMENT Page: 3 of 13
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
WM2010 Conference, March 7-11, 2010, Phoenix, AZ
determined to be acceptable for Tanks 5, 6 and 7 as documented in Liquid Waste System Plan
revision 15 , it results in hundreds of thousands of gallons of spent acid that must be handled.
The spent acid forms oxalates that are anticipated to create evaporator foaming and scaling
problems, increase the volume of water required to wash the sludge, and increase the volume of
Saltstone grout that is produced. For these reasons, the bulk process cannot be accommodated in
the liquid waste system flowsheet over the long term and is therefore not planned for any
additional tanks after Tank 7.
Enhanced Chemical Cleaning is based on adapting proven techniques from the commercial
reactor and steam-generating industries to the cleaning of the SRS and Hanford carbon steel
waste tanks. A dilute acid stream dissolves residual waste and etches steel surfaces to clean tank
internals. The oxalates in the acid stream are then destroyed using a proprietary process
developed by AREVA. The dissolved metals and associated radionuclides precipitate out and are
transferred to a sludge tank. Concentrated oxalic acid or oxalic acid crystals regenerate the acid
cleaning stream for reuse. Since this process can be utilized with minimal impacts on tank space
and downstream processes, the tank cleaning can continue until the residual waste has been
Although bulk oxalic acid cleaning will not be employed long term at SRS, the data and
information collected from the dissolution of sludge heels with bulk oxalic acid will be used to
develop the dissolution process of Enhanced Chemical Cleaning. Waste characteristics, available
infrastructure, deployment methods and acid concentrations of past bulk oxalic acid cleaning
campaigns are evaluated for application to Enhanced Chemical Cleaning for both SRS and
Both SRS and Hanford have used oxalic acid to clean waste tanks. SRS has the most experience
with oxalic acid with four campaigns in Tanks 16, 24, 5 and 6. Hanford used oxalic acid in Tank
Tank 16 was cleaned with oxalic acid in the 1980's. About 1,400 gallons (5300 liters) of sludge
remained in Tank 16 after bulk waste removal was complete. The cleaning campaign consisted
of two water washes, three acid strikes and a final water rinse. The water washes consisted of
60,000 to 70,000 gallons (227,000 to 265,000 liters) of water added with 5 rotary spray jets at
90 C. The oxalic acid strikes were completed as shown in the attached table. The water was
sprayed in at 90 C and 3 slurry pumps were used for mixing. The pumps were also re-located
near the areas of the largest deposits. 
Here’s what’s next.
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Spires, R. & Ketusky, E. COMPARISON OF OXALIC ACID CLEANING RESULTS AT SRS AND HANFORD AND THE IMPACT ON ENHANCED CHEMICAL CLEANING DEPLOYMENT, article, January 5, 2010; South Carolina. (https://digital.library.unt.edu/ark:/67531/metadc931665/m1/3/: accessed April 21, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.