September 24, 2008 

Jean Ridley, Acting Director 

Waste Disposition Programs Division 

U.S. Department of Energy 

Savannah River Operations Office 

P.O. Box A 

Aiken, SC 29802 

SUBJECT: NUCLEAR REGULATORY COMMISSION ONSITE OBSERVATION REPORT 

FOR THE SAVANNAH RIVER SITE SALTSTONE PRODUCTION AND 

DISPOSAL FACILITIES, JULY 31, 2008 

Dear Ms. Ridley: 

The enclosed report describes the U.S. Nuclear Regulatory Commission’s (NRC’s) onsite 

observation activities on July 31, 2008, at the Savannah River National Laboratory (SRNL) at the 

Savannah River Site (SRS). This onsite observation was conducted in accordance with the 

Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), which 

requires NRC to monitor disposal actions taken by DOE for the purpose of assessing 

compliance with the performance objectives set out in 10 CFR Part 61, Subpart C. The activities 

conducted during the site visit were consistent with those described in the NRC’s monitoring 

plan for salt waste disposal at SRS (dated May 3, 2007) and NRC’s staff guidance for activities 

related to waste determinations (NUREG-1854, dated August 2007). 

This onsite observation at SRS was primarily focused on the performance objective in 

10 CFR 61.41, protection of the general population from releases of radioactivity. Since 

saltstone grout production operations could impact the long-term stability of the disposal facility 

after its closure, this observation also partially assessed the performance objective in 

10 CFR 61.44, stability of the disposal site after closure. 

During the previous onsite observation visit in March 2008, DOE presented plans for additional 

studies, including laboratory experiments. These experiments, when completed, are designed to 

provide information DOE needs to address open issues identified by NRC during an observation 

visit in October 2007 as well as to provide additional model support for the Saltstone 

Performance Assessment. The open issues identified by the NRC pertain to: (1) the need for 

additional information to support the physical characteristics of the saltstone grout assumed in 

the DOE waste determination; and (2) the need for additional information which quantifies the 

impact of grout component intrabatch variability, flush water additions, and additives, on final 

saltstone grout physical and chemical properties. 

In July 2008, DOE-Savannah River (DOE-SR) informed NRC that DOE contractor staff at SRNL 

planned to complete three experiments on vault and saltstone grout materials by midAugust 2008. NRC staff visited SRNL on July 31, 2008 in order to observe ongoing experiments 

that will address the first open issue described above, before they were completed. No new 

open issues were identified relating to these observations, and no open issues were closed, as 
J. Ridley 2 

the data from these experiments, data assessments, and updated performance assessments 

are not yet available. 

Based on NRC staff observations, NRC staff continues to conclude that there is reasonable 

assurance that the applicable criteria of the NDAA can be met if key assumptions made in 

DOE’s waste determination analyses prove to be correct. In accordance with the requirements 

of the NDAA and consistent with NRC’s monitoring plan for the salt waste disposal facility, NRC 

will continue to monitor DOE’s disposal actions at SRS. The monitoring activities are expected 

to be an iterative process and several onsite observation visits, and technical reviews of various 

reports, studies, etc., may be necessary in order to obtain the information needed to close all of 

the current open issues, as well as issues that may be opened in the future. 

If you have any questions or need additional information regarding this report, please contact 

David Brown at (301) 415-6116. 

Sincerely, 

 /RA/ 

Patrice Bubar, Deputy Director 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Observation Report 

cc: w encl: 

S. Wilson 

Federal Facilities Liaison 

Environmental Quality Control Administration 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1708
J. Ridley 2 

the data from these experiments, data assessments, and updated performance assessments 

are not yet available. 

Based on NRC staff observations, NRC staff continues to conclude that there is reasonable 

assurance that the applicable criteria of the NDAA can be met if key assumptions made in 

DOE’s waste determination analyses prove to be correct. In accordance with the requirements 

of the NDAA and consistent with NRC’s monitoring plan for the salt waste disposal facility, NRC 

will continue to monitor DOE’s disposal actions at SRS. The monitoring activities are expected 

to be an iterative process and several onsite observation visits, and technical reviews of various 

reports, studies, etc., may be necessary in order to obtain the information needed to close all of 

the current open issues, as well as issues that may be opened in the future. 

If you have any questions or need additional information regarding this report, please contact 

David Brown at (301) 415-6116. 

Sincerely, 

 /RA/ 

Patrice Bubar, Deputy Director 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Observation Report 

cc: w encl: 

S. Wilson 

Federal Facilities Liaison 

Environmental Quality Control Administration 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1708 

DISTRIBUTION: 

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OFC FSME/DWMEP DWMEP/LA FSME/DWMEP FSME/DWMEP FSME/DWMEP 

NAME D.Brown AWalkerSmith A.Kock A.Bradford D.Brown 

DATE 9/11/08 9/17/08 9/19/08 9/22/08 9/24/08 

OFFICIAL RECORD COPY
Enclosure 

SAVANNAH RIVER SITE SALTSTONE PRODUCTION AND DISPOSAL FACILITIES 

U. S. NUCLEAR REGULATORY COMMISSION ONSITE OBSERVATION REPORT 

JULY 31, 2008 

1.0 INTRODUCTION 

On July 31, 2008, NRC staff conducted its third onsite observation visit of the Savannah River 

Site (SRS) Saltstone Facilities. The purpose of this one-day visit was to observe ongoing 

experiments at the Savannah River National Laboratory (SRNL) at the Savannah River Site. 

This visit focused on the performance objective in 10 CFR 61.41, “protection of the general 

population from releases of radioactivity,” by reviewing ongoing laboratory experiments designed 

to collect data on the physical and chemical properties of the SRS Saltstone Disposal Facility 

(SDF) vault and saltstone grout materials. Because the saltstone grout production operations 

could impact the long-term stability of the disposal facility after its closure, this observation also 

was intended to partially assess compliance with the performance objective in 10 CFR 61.44, 

stability of the disposal site after closure. This report provides a description of NRC onsite 

observation activities and identifies NRC observations from the visit. Based on the results of the 

visit, the NRC continues to have reasonable assurance that the performance objectives of 

10 CFR 61 can be met in the areas reviewed. 

2.0 NRC ONSITE OBSERVATION ACTIVITIES 

At the beginning of the visit, DOE contractor staff provided briefings to staff from NRC and the 

South Carolina Department of Health and Environmental Control (SCDHEC) on: (1) the ongoing 

experiments at SRNL that are designed to collect data on physical and chemical parameters of 

the SDF vault and saltstone grout; and (2) the current status of salt waste processing. DOE 

briefing slides are included in Attachments 1 and 2. With regard to the experiments, DOE 

contractor staff explained that there are three main types of experiments at different stages of 

completion. These experiments include: (1) batch studies of absorption and desorption rates of 

key radionuclides from a pulverized simulated concrete and grout, which are 75% complete, and 

which DOE estimates will be complete in September 2008; (2) studies of technetium-99 

oxidation and release rates from crushed samples of laboratory-prepared saltstone grout, which 

DOE estimates are about 50% complete; and (3) studies of the reduction capacity of saltstone, 

grout, which are complete. 

With regard to the batch studies of absorption and desorption rates of key radionuclides from a 

pulverized simulated vault concrete and saltstone grout, DOE contractor staff explained that 

three saltstone grout mixtures are being studied that are representative of three liquid waste 

processing streams: (1) deliquification, dissolution, and adjustment (DDA); (2) actinide removal 

process / modular caustic side solvent extraction unit (ARP/MCU); and (3) the Salt Waste 

Processing Facility (SWPF). The data collected in these experiments is used to calculate 

distribution coefficients, or Kd values, which are key parameter values in the DOE performance 

assessment. DOE explained that the current experiments are not testing the effects of grout 

additives such as anti-foaming agents or set-retardant. However, DOE may conduct such 

experiments in the future, subject to prioritization of research needs and available funds. 
2 

The experiments to collect data on the reducing capacity of saltstone grout are using a 

colorimetric titration technique to oxidation endpoints measured using a spectrophotometer. The 

indicator is based on the reduction-oxidation couples of cerium and chromium . 

The experiments on the oxidation of saltstone grout and desorption rates of technetium-99 in 

saltstone grout are batch experiments. In these experiments, crushed laboratory-prepared 

saltstone grout is added to small, sealed serum bottles with simulated, highly-buffered saltstone 

grout pore water. The grout and water mixture is equilibrated by tumbling or shaker table, which 

requires several days. Equilibrium is indicated by stable pH measurements, at which time the 

technetium-99 spike is added to the mixture. Aqueous technetium-99 concentrations are 

measured at regular time intervals throughout the experiment. Aqueous phase technetium-99 is 

determined after filtration of the leachate through 100 nanometer pore filters. Early results 

indicate that equilibrium technetium-99 adsorption is reached within 5 hours. After one week, air 

is sparged into the serum bottles, and technetium-99 aqueous phase concentrations continue to 

be measured at regular time intervals. 

NRC staff did not review preliminary results for any of the experiments, as data validation and 

data assessment for all laboratory experiments is pending. As a result, the two open issues 

pertaining to saltstone characterization that are summarized in the NRC’s observation report for 

the March 24-28, 2008, observation visit remain open. These open issues pertain to: (1) the 

need for additional information to support the physical characteristics of the saltstone grout 

assumed in the DOE waste determination; and (2) the need for additional information which 

quantifies the impact of grout component intrabatch variability, flush water additions, and 

additives, on final saltstone grout physical and chemical properties. In addition, NRC staff 

expects to review the results of these experiments as part of the monitoring of Factor 3: Model 

Support described in Section 3.1.4 of NRC’s Monitoring Plan for Salt Waste Disposal at SRS. 

NRC and DOE contractor staff also discussed whether soil sampling and analysis results for 

samples taken in the vicinity of the Saltstone Disposal Facility (SDF) were available for NRC 

technical review. These sample were taken in the vicinity of weep sites in Vault 4. DOE 

contactor staff stated that sample analysis results were available, but that additional time is 

needed to complete a data assessment. NRC staff will follow up on the availability of this 

information for NRC technical review. 

DOE contractor staff also provided an update to NRC and SCDHEC staff on salt processing. Of 

note, as described in the Attachment 2, DOE has started ARP/MCU processing under a 

Management Control Plan, which involves a heightened level of administrative controls on 

operations, including cross-checks, various process hold points for management review and 

approval, and higher sampling rates. The performance of the ARP/MCU processing is of 

interest to NRC staff because the amount of removal achieved during this process affects the 

inventory of radionuclides disposed of at the Saltstone Disposal Facility and consequently the 

dose that a receptor may receive. 

DOE contractor staff explained that they have experienced some start-up challenges with MCU, 

including loading of a Decontaminated Salt Solution (DSS) coalescer. The accumulation of 

monosodium titanate solids on the coalescer media occurred more rapidly than anticipated, 

starting with the fifth of what was expected to be a series of 10 DSS batches under the 

Management Control Plan. The coalescer media in the crossflow filter protects contactors 

located downstream in the MCU process. DOE contractor staff explained that the rate of 

coalescer media loading does not present a process safety hazard. Lessons-learned on 
3 

equipment start-up are being shared with Parsons, which is designing the SWPF. 

DOE contractor staff explained that the ARP/MCU process is performing better than desired 

production goals. However, the process has been treating “startup simulant” from Tank 49, for 

which higher decontamination factors are expected. DOE will continue treating additional 

batches of ARP/MCU feed material, and expect that equilibrium processing rates and 

performance will be reached within ten batches following replacement of the coalescer media. 

DOE had processed a total of 13 batches at the time of the NRC observation visit. No 

radionuclide removal data was available for NRC technical review during the visit. However, 

DOE is preparing a technical report on the results of start-up operations under the Management 

Control Plan. In addition, the sampling protocol for the ARP/MCU process is being developed. 

NRC staff will follow up on the availability of these documents in the future. 

Following discussion of the three types of experiments, and the update from DOE contractor 

staff on the status of salt processing, NRC and SC DHEC staff were provided a tour of ongoing 

experiments in the laboratory. 

In the afternoon, NRC and DOE staff discussed which routine reports DOE and/or DOE 

contractor staff prepare for which NRC would like to be on distribution. NRC and DOE also 

discussed the schedule for the preparation of technical reports pertaining to the laboratory 

experiments observed during this visit, and other ongoing studies. 

3.0 CONCLUSIONS 

During this onsite observation visit, NRC and SC DHEC staff were afforded an opportunity to 

observe ongoing laboratory experiments, and ask clarifying questions on the design and scope 

of the experiments. NRC and SC DHEC staff also received a briefing on the status of salt waste 

processing operations, but did not request a tour of the Saltstone Facilities, or review onsite 

documentation pertaining to ongoing operations. Given the limited scope of the onsite 

observation, and the fact that experimental data and data assessments are not yet available, 

staff did not close open items that were described in the NRC’s observation report for the 

March 24-28, 2008, observation visit. 

Based on NRC staff observations, NRC staff continues to conclude that there is reasonable 

assurance that the applicable criteria of the NDAA can be met if key assumptions made in 

DOE’s waste determination analyses prove to be correct. In accordance with the requirements 

of the NDAA and consistent with NRC’s monitoring plan for the salt waste disposal facility, NRC 

will continue to monitor DOE’s disposal actions at SRS. The monitoring activities are expected 

to be an iterative process and several onsite observation visits, and technical reviews of various 

reports, studies, etc., may be necessary in order to obtain the information needed to close all of 

the current open issues, as well as issues that may be opened in the future. 

4.0 PARTICIPANTS 

NRC and State of South Carolina Observation Team 

Anna Bradford, NRC 

David Brown, NRC 

Karen Pinkston, NRC 

Jason Shirley, SC DHEC 

Ted Millings, SC DHEC 
4 

U.S. DOE and Contractor Representatives 

Seaward Middleton, DOE-SR David Little, WSRC 

Howard Pope, DOE-SR Jeff Newman, WSRC 

Sherri Ross, DOE-SR Larry Romanowski, WSRC 

Ginger Dickert, WSRC Kent Rosenberger, WSRC 

Dan Kaplan, WSRC F. Malcolm Smith, WSRC 

Attachments: 

1. “Batch Kd Measurement,” Dan Kaplan, WSRC, undated 

2. “Salt Processing Update,” David Little, WSRC, dated July 31, 2008.