# Presentation: 214596

## Phase Chemistry of Tank Sludge 

**Residual Components**
**Principal Investigators:**
**J.L. Krumhansl, SNL (505) 844-9093**
**(jlkrumh@sandia.gov)**
**P.V. Brady, SNL (505) 844-7146**
**J. Liu,PNNL, (509) 375-3430**
**K.L. Nagy, C.U., (303) 492-2606 **

## Principal investigators:

**	****J.L. Krumhansl, SNL**
**	****P.V. Brady, SNL**
**	****J. Liu, PNNL**
**	****K.L. Nagy, C.U.**
**Contributors:**
**	****M.A. Molecke, SNL**
**	****H.L. Anderson,  SNL**
**	****C. Bryan, SNL**
**	****S.M. Von Drasek, SNL**
** **

## Problem: The chemistry of tank sludges is poorly known

**Problem:** The chemistry of tank sludges is poorly known
-  and incredibly expensive to measure (~106$ per sample).
- Result: It is impossible to predict the composition of the after-cleaning residuum, or the long-term health threat it will pose.

**Our Approach:** Develop tank sludge simulants that can be used to estimate long-term residuum stability.

- 1. Must demonstrate that the major element behavior of the
-  tank sludge simulants matches that of real tank sludges.
- 2. Must then measure the chemical stability/leachability of
-  trace elements (Radionuclides) in tank sludge residuum simulants.

*We greatly appreciate funding by the Environmental Science Management Program (EM-52)*

## Methodology

**1. Use process knowledge to identify waste streams and then synthesize appropriate sludges.**
**2.  Compare the phase chemistry of synthetic and HLW  tank sludges.**
**4.  Evaluate the behavior of radionuclides in association  with the principal sludge components. **
**5. Assess how the sludge phases will age and how the radionuclides will respond to changing environments.  **

## I	How did sludges originate?

## Early Waste Reprocessing Activities

**BiPO****4**** Process:  **Fuel was dissolved in HNO3
- and Pu separated by co-precipitating on
- BiPO4 and LaF3.  U was discarded as a heavy metal waste along with 90% of the fission products.  Other wastes contained 10% of the fission products as well as some of the Al cladding and process chemicals ( #1 ).
**TBP Process:  **BiPO4 metal wastes were
- re-acidified and the U recovered by solvent
- extraction.  Wastes include the remaining
- 90% of the fission products ( #2 ).

## A

-        0  MTU Zr clad fuel
- 7,800  MTU Total

**BiPO****4**** Process**

- Remove Cladding

- BiPO**4** Ppt.
-  Pu Removed

- “CW” Waste
- Al + 1% FP

- “HM” Waste
- U + 90% FP

- Purify Pu

- 1C
- Waste
- 9% FP

- N

- Storage

- N

- N

- BiPO4
- Waste

- U-Recovery

- 5% of  Inventory

- 95% of inventory

- N

- U-Recovery
- Waste

**Early Reprocessing Technologies**

**#1**

**#2**

**TBP Process**

- MTU  Metric Tons Uranium
- N    Neutralized
- A    Acidified
- FP Fission Porducts

## Later Waste Reprocessing Activities

**REDOX Process:  **After cladding removal fuel
- was dissolved in nitric acid.  Wastes contained
- Na2Cr2O7, Al(NO3)3, and Fe+2-sulfamate that
- was added to facilitate U and Pu removal by
- solvent extraction with MIBK ( #3 ).
**PUREX Process:** Fuel was dissolved in nitric
- acid and both U and Pu were extracted with
- TBP.   The first PUREX waste streams came
- from Al clad fuel ( #4 ).  Later PUREX wastes
- involved reprocessing Zr clad fuels ( #5 ).

##          Later Reprocessing Technologies

- 19,461  MTU Al Clad Fuel
-      245  MTU Zr Clad Fuel
- 19,706  MTU Total

- 65,924  MTU Al Clad Fuel
-   5,463  MTU Zr Clad Fuel
- 71,387  MTU Total

**REDOX Process**
- MIDDLE

**PUREX Process**
- Current Technology

- A

- Remove Cladding

- Remove Cladding

- CW
-  Waste

- N

- Pu, U
- Recovery

- Early PUREX
- HLW Storage

- B-Plant Cs
- and Sr Recovery

- most

- N

- CW
-  Waste

- A

- Pu, U
- Recovery

- A

- N

- A

- A

- N

- PUREX waste
- with some Sr, Cs gone

- Minor but
- with more Sr, Cs

- N

- REDOX
- HLW Storage

- Minor early
- mixing

- Cs removal
- only

- No acid used

- REDOX waste
- lower Cs

**#3**

**#4 Al clad fuel**
**#5 Zr clad fuel**

## Simplified Waste Stream Chemistry (molar)

- 	**BiPO****4****	****#1****	****TBP****#2****	****	****REDOX****#3****	****PUREX****#4**** PUREX****#5**
**	****(Al Clad)****	****(Al Clad)****	****(Al>Zr)****	****(Al>Zr)    (Zr Clad)**
**Al****	****8E-2****	****	****0****	****	****1.1****	****	****8E-1****	****      0**
**Fe****	****3E-2****	****	****5E-2****	****	****5E-2****	****	****1E-1****	****      4E-2****	**
**Cr****	****3E-3****	****	****3E-3****	****	****7E-2****	****	****8E-3****	****      3E-3**
**Ni****	****2E-3****	****	****2E-3****	****	****4E-3****	****	****1E-2****	****      1E-3****	**
**Zr****	****3E-4****	****	****0****	****	****0****	****	****0****	****      1E-1**
**Bi****	****1E-2****	****	****0****	****	****0****	****	****0****	****      0**
**Ca****	****2E-2****	****	****2E-2****	****	****0****	****	****6E-2****	****      2E-2**
**Si****	****6E-2****	****	****4E-3****	****	****4E-2****	****	****5E-2****	****      0**
**F****	****2E-1****	****	****0****	****	****0****	****	****0****	****      8E-1**
**P****	****3E-2****	****	****1E-1****	****	****0****	****	****2E-2****	****      0**
**Pb****	****4E-4****	****	****1E-4****	****	****1E-2****	****	****1E-3****	****      0**
**Mn****	****7E-3****	****	****0****	****	****0****	****	****3E-2****	****      0**
**Cd****	****1E-5****	****	****8e-6****	****	****0****	****	****1E-3****	****      1E-3**
- Agnew, S.F., 1997, Hanford Tank Chemical and Radionuclide Inventories, Rev. 4, LA-UR-96-3860
- Colton, N.G., 1994, Sludge Pretreatment Chemistry Evaluation:Enhanced Sludge Washing  Separation Factors,TWRSPP-94-053, Appendix E
- Kupfer, M.J., et al., 1997, Standard Inventories of Chemicals And Radionuclides in Hanford Site Tank Wastes, HNF-SD-WM-TI-740

## Reprocessing eventually produced five

**Reprocessing eventually produced five**
**major waste streams that were made **
**strongly basic prior to storage in tanks.**
**Most sludge components precipitated **
**during or shortly after this process.**

## II 	What phases precipitate during

**II ****	****What phases precipitate during**
**	**** ****artificial sludge preparation?**** **