# Presentation: 476920

## High Level Waste Characterization at SRS

**Joe Carter, Manager, Salt Waste Program Engineering**
**Fatina Washburn, HLW Process Engineering**
**December 18, 2001**

**Notes:**
Good Morning/Afternoon.

Introductions of Guests.

I plan to present  a General Overview of High Level Waste Characterization at the Savannah River Site - our history, our current structure and our pathforward.

## Discussion Outline

**HLW Overview/Tank Farm Introduction**
**Current Waste Characterization System (WCS)**
**Risk Based Characterization Approach to Operations**
**Accomplishments to Date**
**Future Plans**

**Notes:**
First, I will give you a little bit of information on High Level Waste Division.             How waste is received, the general types of waste, and it’s overall disposition.

Then I will discuss the divisions Waste Characterization system.  How it was derived, the type of information it contains, and it’s many uses.

Next, I will describe how our waste characterization system has been incorporated in our risk based approach to operations.  I will briefly go through the batch characterization process as it relates to the Defense Waste Processing Facility and the Salt Processing Facility  as well as some photographs and sketches of some of our sampling equipment and devices.

I also have a brief status slide on how WCS has assisted in our sites accomplishments in tank closure and operations.

Finally, I will address our future plans to improve our characterization efforts at the Savannah River Site.

## HLW SYSTEM

**HLW SYSTEM**

## HLW Tank Usage

## Waste Characterization System (WCS)

**Used to track the composition in each tank**
**Sludge, salt, and supernate are described separately**
**41 radionuclides**
**48 chemical species**
**23 other waste characteristics**
**Dynamic system**

**Notes:**
The High Level Waste Division’s Waste Characterization System is a compilation of various parameters based on material irradiation and process records as well as ongoing sampling efforts.

WCS is used to track the composition in each individual tank with sludge, crystallized salts, and aqueous salt solutions described separately within the database.

It contains radionuclide and chemical information as well as other waste characteristics such as temperature, tank level, pH, etc.

Since the tank farms are dynamic in that fresh waste continues to be received, transferred and processed to reduce the stored waste volume and to provide feed to DWPF, WCS is also dynamic and is updated as new information on individual tanks becomes available

## Waste Characterization System (WCS)

**System Inputs**
- Process/Flowsheet Records
- Waste Transfers
- Tank Inventories
- Evaporator Operations
- Solubility Studies
- Chemical Properties
- Field Measurements
- Sampling Activities

**Uses**
- HLW System Activities
- Radiolytic Heat Loads
- Hydrogen Generation Rates
- Accident Analyses
- Tank Closures
- Waste Removal Planning
- Emergency Response Data Reports
- Criticality Assessments

**Notes:**
There are a number of data sources that are compiled in WCS.  I have listed general sources here such as process/operating  records, inventories, field measurements and sampling results. I think it is important to note that logic is embedded in the database for conflict resolution between data sources.

There are a number of uses of the information provided by WCS.  As I meet the individual users, the list of uses is ever increasing, but I have described the general categories here.  Divisional/system planning, regulatory planning and various safety aspects all use the information in WCS as input.

I would like to point out that the Emergency Response Data Reports are direct outputs from WCS.  

Other uses generally extract specific information in tabular formats for either direct use or further manipulation.

## Waste Characterization System (WCS)

**Access controlled system**
**Validation by a Subject Matter Expert Review Team **
- Reviews all inputs monthly
- Reviews/documents safety related outputs per SRS procedures
- Non-safety related outputs are reviewed for reasonableness
**Continually Evolving System**
- New functionality added in response to requirement changes (e.g. Technical Safety Requirement implementation)

**Notes:**
     There are currently about  65 controlled users of WCS.
     Access is strictly controlled in that there is only one person or designee allowed to make changes to the system.  The remaining users have read-only access.
     The data are reviewed and validated on a monthly basis.  A Data Integrity Review Team is established to ensure that all inputs and outputs are rigorously controlled.
    All safety related and special outputs (e.g. criticality evaluations) are reviewed and documented in accordance with site procedures for verification and checking.
     Any formula or logic changes to the database are reviewed in this same manner with additional technical review requirements to determine if the changes involve Unreviewed Safety Questions.
    Non safety reviews are reviewed for reasonableness but formal reviews are not performed.
     WCS is a system that continually has evolved and added functionality as needs and requirements have changed.  It originally started in support of the DWPF production model and has evolved to accommodate the uses that were described on the previous slide.

## Waste Characterization and Planning

**Most storage tank samples are driven by TSRs**
**Annual plan developed for routine samples**
- Purpose (process, monitoring, corrosion, etc.)
- Sample location
- Sample matrix identified
- Sample frequency
- Laboratory for analysis
- Sample Owner
**Ad hoc samples**
- Driven by Technical Request Forms
- Coordinated with Operations
- R & D Samples

**Notes:**
Most of the actual storage tank samples are driven by the technical safety requirements and are either organic samples or anion samples for corrosion chemistry.

Sump and evaporator overhead samples as well as legionella cooling tower analysis are also captured in the annual sampling plan.

The sampling  plan outlines the purpose of the sampling, where the sampling is required, how often it is required, what analytes will be analyzed, who will do the analysis and who is requesting the sampling.  This plan is developed annually for routine samples.

Non routine samples are integrated by use of a technical request forms and are coordinated with operations through the High Level Waste Engineering group.

## Salt Core Sampler

- Photo provided by Tom Nance, SRTC

**Notes:**
I wanted to show you a couple of examples of our sampling devices.  This is a photograph of a salt core sampler.  

Rods are attached and the device is lowered into the tank.  Once the salt layer is reached, the sampler is tamped into the salt layer. 

There is an indicator on the top to ensure a sample in the cup.  

There is also a mechanism to ensure liquid escapes while salt is maintained in the cup.

## Dip Filter Sampler

**Dip Filter Sampler**

- Photo provided by Tom Nance, SRTC

**Notes:**
This is an example of a dip filter sampler.  The sampler is allowed to collect supernate from the surface.

A filter is installed and the sampler is filtered prior to entering the sample vial.

## Slide 11

**Notes:**
Now I’m going to discuss how WCS fits into the overall scheme of characterization for overall facility operations.

First, initial blending profiles are established for the facility using the characterization information in WCS.  Blending profiles are established to provide a consistent feed stock to the facility.

Next, bench scale testing with simulant and real waste establish the initial operating windows for the facility.

Pilot scale testing or qualification testing is performed using simulant and/or real waste to ensure that our operating envelope is capable of treating  wastes specified in the blending profiles.

Next, prior to treatment, each transferred blend is fully characterized  to ensure it is within the prescribed blending profile and subsequently the operating envelope.  It is also our intent to capture this information to further refine WCS.

Once confirmed, the facility is ready to accept the blend for operation.

## Current Characterization

**Current Characterization**

**Process History**

**- Purex and HM Processes**

**- Essential Materials**

**   ****Reactor Burn-up Profiles**

**Fundamental Understanding**

**- Chemical Solubilities**

**Sample Analysis**

**- Elemental**

**- Radionuclides**

**- Anion/Cation**

**Current Understanding**

**(Waste Characterization Database)**

- .

**UNCERTAINTY**

**- Changes with time**

**- Exact splits of key species (Al, Hg, Sn, Sb)**

**- Oxidation state (Cr, Mo, Tc)**

**- Mixed metal oxides vs simple compounds**

**- SaltCake Stratification**

**R&D Studies**

**Macro Batch**

**Characterization**

_**UPDATES**_

- - Monthly for Transfers

- - Periodic Surveillance Samples

- - Receipt of Sample Analysis

**Notes:**
This is another representation of the risk based approach, which shows the various inputs to the current characterization system and  the further refinement of variables through R&D studies.

And eventhough we acknowledge the risks of uncertainty, these risks are reduced by our macrobatch characterization process  approach.

## Blending Strategy

**Process Window**

**Tank 1**

**C**

**1**

**C**

**2**

**C**

**n**

**Tank n**

- C

- 1

- C

- 2

- C

- n

**Tank 2**

**C**

**1**

**C**

**2**

**C**

**n**

**C**

**1**

**C**

**2**

**C**

**n**

**SLUDGE**

**PROCESS**

**SALT**

**PROCESS**

**Glass**

**Window**

**Frit**

**Salt**

**Sludge**

**Saltstone**

**Window**

**Radionuclides**

**Hazardous Waste**

**Cs**

**Alpha**

**Sr**

## Waste CharacterizationRisk Management Approach

**Notes:**
This risk management approach has been defined and used for sludge processing at SRS.

First, blending profiles were established using the information in WCS and canyon process history records.

Next, bench scale tests were performed on real wastes to determine initial operating windows.

A number of activities occurred during the qualification step.  Simulants were ran in a 2/3 scale melter to demonstrate the viability of the melter technology.  A 1/10th or (actually 1/9th) scale melter was used to integrate the entire vitrification process (the SRAT, SME and melter feed tank).  Glass composition durability testing also occurred during this phase on both real waste and simulant.  This established the operating envelope for DWPF.

Simulants representing average, HM, and PUREX waste were also ran through the full scale facility prior to rad operations.

Macrobatch characterization has been completed for the first two macrobatches and is underway for the third macrobatch.

We are currently processing preparing to process Macrobatch 3 through the full scale facility.

## Defense Waste Processing Facility

- Photo provided by Steve Gavin, HLW

**Notes:**
All of the process tanks use Hydrogard samplers.  This is a picture describing this sampling procedure.

First, the pump can be primed with water as necessary.

Next, the sample is pump from the tank through the sample loop.  Valves are configured to allow the sample to enter the sample cup.  An outlet line allows the overflow to be transferred to the drain header.

Then,valves are manipulated to allow flush water to enter and clean the sample lines.

## Defense Waste Processing Facility

- Photos provided by Dan Iverson, HLW

**Notes:**
As I mentioned, one liquid sample is required per macrobtach.  This shows the location of the sampler during operation, as well as the position of the sampler for sample collection.

## Defense Waste Processing Facility

**Statistical Reviews of Process Samples for Each Macrobatch**
- Cation Dissolution Methods
- Between/Within Process Vessels
- Process Variability vs. Product Composition Control System Data

**Notes:**
Once the macrobatch is processed, statistical reviews of the process samples are conducted.

Two dissolution methods are used to analyze all of the constituents.  One method can be analyzed for all constituents except for boron while the other method can be analyzed for all except for sodium.  This allows for a statistical review of most components relating to different dissolution methods.

The results are also examined for variability between and within process vessels, and how the process varies with the predictive model.

## Waste CharacterizationRisk Management Approach

**Notes:**
As for sludge, we also have a similar risk based approach to characterization with blending profiles,  real waste bench scale and pilot facilities as well as macrobatch characterization..

## Future Salt Disposition

**Salt Disposition Strategy****	****	****	****	**
- Low Curie Salt Waste Direct to Saltstone (no treatment)
- Actinide Removal from Low Curie Waste followed by Disposal in Saltstone
- Actinide Removal followed by future treatment of the resulting stream rich in Cs
- Caustic Side Solvent Extraction
**Initial blending profiles developed from WCS for full scale facility**
- 67 batches identified
- 1.25 MG per batch
**Development of Feed Basis for New Salt Disposition Strategy**
- Low Curie (underway)
- Actinide Removal (underway)
- CSSX (TBD)

**Notes:**
As for the salt processing facility, the technology that has been selected is alpha sorption followed by caustic side solvent extraction to remove the cesium.

Blending profiles have been established utilizing WCS.  There are a total of 67 batches with all but the last batch being 1.25 MG.

Following the risk management approach, real waste and simulant testing has occurred to establish  the initial operating windows.  

Our Waste Acceptance Criteria and Waste Compliance Plans are currently under development.

## Future Salt Disposition

**Initial Operating Windows Defined**
- Real waste bench scale testing
- Bench scale simulant testing
**Confirm Operating Windows**
- Testing may include simulants, tracers, and real waste
**Macrobatch Characterization**
- Targeted for FY07

**Notes:**
Pilot Scale facilities are currently in design to process simulant and real waste.  The facility will be approximately 1/100th scale.

Operation of the pilot is scheduled for FY03 with real waste testing currently scheduled in March.

The first full scale macrobatch characterization is currently targeted in FY09 for a FY10 operation start-up.

## RFP Waste Characterization Information

**Information as of October 2001**
**Volume Estimates from WCS**
**Cesium & Alpha Concentrations derived from WCS**
**Soluble Strontium based on Analytical Information**
**Projected Feed Volumes Calculated @ 6.44 M Sodium**

## Accomplishments Assisted by WCS

**2 Tank Closures**
- Tank 20
- Tank 17
**1219 Canisters of Glass Poured (as of 12/11/01)**
- FY96	  64
- FY97	169
- FY98	250
- FY99	236
- FY00	231
- FY01	227
- FY02	42 (as of 12/11/01)

**Notes:**
To wrap things up, well, what have we accomplished with our current characterization system?

We have closed two High Level Waste tanks and have preparations underway for the third and fourth tank closures (Tanks 19 and 18).

## Future Plans

**Implementation of Waste Characterization Action Plan**
- Continuation of Risk Based Approach
- Successfully demonstrated for sludge processing
- Development of a New, User Friendly Waste Characterization Database
- Data field expansion (traceability, QA information)
- Incorporation of New Data as it becomes available
- Supernate
- Dissolved Salt
- Bench/Pilot Real Waste Tests
- Macrobatch Characterization
- Integrated Sampling Schedules for HLW needs
- Waste Removal
- Waste Treatment
- Disposition Activities

**Notes:**
What are our future plans at SRS?

Based on our successes with sludge, we plan to continue a risk based approach to characterization.

We plan to incorporate the macrobatch information into the characterization database to further refine our blending strategies.

We plan to integrate sampling activities  for division programs so as to minimize personnel exposure and cost

And last but bot least, we have plans to develop a more user friendly database for waste characterization that will provide for expansion while  maintaining its current functionality.