August 19, 2011 

Mr. Thomas Gutmann, Director 

Waste Disposition Programs Division 

U.S. Department of Energy 

Savannah River Operations Office 

P.O. Box A 

Aiken, SC 29802 

SUBJECT: U.S. NUCLEAR REGULATORY COMMISSION APRIL 26, 2011 ONSITE 

OBSERVATION REPORT FOR THE SAVANNAH RIVER SITE SALTSTONE 

FACILITY 

Dear Mr. Gutmann: 

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

observation activities on April 26, 2011, at the Savannah River Site (SRS) Saltstone Facility. 

This onsite observation was conducted in accordance with Section 3116 of the Ronald W. 

Reagan National Defense Authorization Act for Fiscal Year 2005 (Section 3116), which requires 

NRC to monitor disposal actions taken by the U.S. Department of Energy (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 focused on assessing compliance with the four 

performance objectives: (i) protection of the general population from releases of radioactivity 

(§61.41), (ii) protection of individuals from inadvertent intrusion (§61.42), (iii) protection of 

individuals during operations (§61.43), and (iv) stability of the disposal site after closure 

(§61.44). Meeting these performance objectives is predicated on the performance of the 

disposal cells within the period of compliance. 

NRC continues to conclude that there is reasonable assurance that the applicable criteria of 

Section 3116 can be met, if key assumptions made in DOE’s waste determination analyses 

prove to be correct. In accordance with the requirements of Section 3116 and consistent with 

NRC’s monitoring plan for the Saltstone Disposal Facility (SDF), NRC will continue to monitor 

DOE’s disposal actions at SRS. Presently, three issues previously identified by the staff remain 

open: (1) the hydraulic and chemical properties of the saltstone grout, (2) the variability of 

saltstone from batch to batch, and (3) the reduction and retention of Technetium-99 within the 

saltstone waste form. Further onsite observation visits and technical reviews may be necessary 

in order to obtain the information needed to close all of the current open issues, as well as other 

issues that may be opened in the future. 
T. Gutmann 2 

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

Nishka Devaser of my staff at (301) 415-5196. 

Sincerely, 

 /RA/ 

Andrew Persinko, Deputy Director 

Environmental Protection 

 and Performance Assessment Directorate 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Observation Report 

cc w /enclosure: 

WIR Service List 

S. Wilson 

Federal Facilities Liaison 

Environmental Quality Control Administration 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1708
T. Gutmann 2 

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

Nishka Devaser of my staff at (301) 415-5196. 

Sincerely, 

Andrew Persinko, Deputy Director 

Environmental Protection 

 and Performance Assessment Directorate 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Observation Report 

cc w /enclosure: 

WIR Service List 

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: GAlexander ARidge KPinkston DEsh 

ML111890319 

OFC DWMEP:PM DWMEP:PM DWMEP:LA DWMEP:BC DWMEP:BC DWMEP:DD

NAME JShaffner NDevaser AWalkerSmith CMcKenney GSuber APersinko 

DATE 7/08/11 7/08/11 7/11/11 7/11/11 8/05/11 8/19/11 

OFFICIAL RECORD COPY
U.S. NUCLEAR REGULATORY COMMISSION APRIL 26, 2011 ONSITE OBSERVATION 

REPORT FOR THE SAVANNAH RIVER SITE SALTSTONE FACILITY 

EXECUTIVE SUMMARY: 

The U.S. Nuclear Regulatory Commission (NRC) staff conducted its eleventh onsite observation 

visit, Observation 2011-02, to the Saltstone Facility at the Savannah River Site (SRS) on 

April 26, 2011. The purpose of this visit was to focus on compliance with the performance 

objectives set out in 10 CFR Part 61, Subpart C: (i) protection of the general population from 

releases of radioactivity (§61.41), (ii) protection of individuals from inadvertent intrusion 

(§61.42), (iii) protection of individuals during operations (§61.43), and (iv) stability of the 

disposal site after closure (§61.44). To accomplish these goals, NRC staff discussed testing of 

saltstone properties, Vault 4 inventory, disposal unit construction, and recent research on Tc 

reduction and oxidation in saltstone performed by SRS. This report provides a description of 

NRC onsite observation activities and identifies NRC observations made during 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, as long as key 

assumptions made in the U.S. Department of Energy’s (DOE’s) waste determination analysis 

prove to be correct. 

There are no new open issues resulting from this observation. The NRC staff received 

documentation during the observation that pertained to the observation activities scheduled for 

this onsite observation. Each of the documents received by the NRC staff during the 

observation are accessible via NRC’s document repository, the Agencywide Documents Access 

and Management System (ADAMS), via the package accession number ML111310169. 

A summary of the staff’s observations and conclusions is provided below: 

Technical Discussion – Saltstone Radionuclide Inventory:

• DOE contractor staff presented a reevaluation of the inventory of I-129 currently 

disposed of in Vault 4 based on sample results. The NRC staff believes that the method 

used for this reevaluation seems reasonable. NRC staff will continue to monitor DOE’s 

inventory tracking methodology. 

• DOE provided NRC staff with an updated inventory document containing the inventory of 

radionuclides disposed in the Saltstone Disposal Facility as of 9/30/10. 

Technical Discussion – New Research on Long-Term Testing Waste Oxidation and Technetium 

Release:

• DOE proposed closing Open Issue 2009-1 due to successful results of recent research. 

NRC expressed concern with some details of the new research. 

• NRC staff concerns with new research were sufficient such that Open Issue 2009-1 

remains open. 
2 

Discussion of Disposal Unit 2 Construction:

• DOE discussed their strategy for repairing the hydraulic leaks and provided 

documentation describing the design changes made to the new disposal cells. 

• The NRC staff will continue to monitor the construction of the new disposal cells. 

Follow-up Discussion – Topics from Previous Observations:

• In addition to the specific technical discussions that took place during the observation, 

additional topics were discussed to follow-up on discussions that took place during 

previous observation activities. A detailed list and description of these topics can be 

found later in this report. Several items were closed from this discussion; however, 

some items discussed remain open and will require further discussion. 

1.0 BACKGROUND: 

Section 3116 of the National Defense Authorization Act for Fiscal Year 2005 (Section 3116) 

authorizes DOE, in consultation with the NRC, to determine that certain radioactive waste 

related to the reprocessing of spent nuclear fuel is not high-level waste, provided certain criteria 

are met. Section 3116 also requires NRC to monitor DOE disposal actions to assess 

compliance with the performance objectives in 10 CFR Part 61, Subpart C. 

On March 31, 2005, DOE submitted a “Draft Section 3116 Determination Salt Waste Disposal 

Savannah River Site” to demonstrate compliance with the Section 3116 criteria including 

demonstration of compliance with the performance objectives in 10 CFR Part 61, Subpart C 

(DOE, 2005a). In its consultation role, the NRC staff reviewed the draft waste determination 

and concluded that there was reasonable assurance that the applicable criteria of Section 3116 

could be met, provided certain assumptions made in DOE's analyses are verified via monitoring. 

NRC documented the results of its review in a Technical Evaluation Report issued in December 

2005 (NRC, 2005). DOE issued a final waste determination in January 2006 taking into 

consideration the assumptions, conclusions, and recommendations documented in NRC’s 

Technical Evaluation Report (DOE, 2006). 

To carry out its monitoring responsibility under Section 3116, NRC performs three types of 

activities: (i) technical reviews, (ii) onsite observations, and (iii) data reviews in coordination 

with the State of South Carolina site regulator, South Carolina Department of Health and 

Environmental Control (SC DHEC). These activities focus on key assumptions – called “factors” 

– identified in the NRC monitoring plan for salt waste disposal at SRS (NRC, 2007). Technical 

reviews generally focus on obtaining additional model support for assumptions DOE made in its 

Performance Assessment (PA) that are considered important to DOE's compliance 

demonstration. Onsite observations generally are performed to (i) observe the collection of data 

(e.g., observation of waste sampling used to generate radionuclide inventory data) and review 

the data to assess consistency with assumptions made in the waste determination, or 

(ii) observe key disposal (or closure) activities related to technical review areas (e.g., slag and 

other material storage, grout formulation and preparation, and grout placements). Data reviews 

supplement technical reviews by focusing on monitoring data that may also indicate future 
3 

system performance or by reviewing records or reports that can be used to directly assess 

compliance with performance objectives. 

2.0 NRC ONSITE OBSERVATION ACTIVITIES: 

The observation began with a short briefing on the observation agenda and site safety 

procedures presented by the DOE contractor, Savannah River Remediation (SRR) and 

attended by representatives from DOE, NRC, Savannah River National Laboratory (SRNL), and 

SRR. The observation continued with a discussion between NRC, DOE, and associated DOE 

contractor staff regarding the inventory of Vault 4, the new technetium oxidation research, and 

various follow-up discussions from previous observations. Sections below contain detailed 

accounts of these discussions. 

2.1 Technical Discussion – Saltstone Radionuclide Inventory 

2.1.1 Observation Scope:

As noted in Section 3.1.1.1, “Data Reviews – Radioactive Inventory” of the May 2007 monitoring 

plan, it is important for NRC staff to verify the radioactive inventory disposed of at the Saltstone 

Disposal Facility because the inventory is an important factor in the compliance with the 

performance objective identified in §61.41, “Protection of the General Population from Releases 

of Radioactivity” and §61.42 “Protection of Individuals from Inadvertent Intrusion.” 

2.1.2 Observation Results:

During the observation, DOE provided a presentation for discussion on Vault 4 Inventory 

Reporting (ML111310182). The discussion focused on the calculated inventory of I-129 and the 

inventory of I-129 assumed for Vault 4 in the 2009 Performance Assessment (PA). 

NRC staff sent an email containing three questions related to inventory to DOE prior to this 

April 2011 onsite observation. The questions and DOE’s responses are listed below. 

NRC Inventory Question Discussion Points

NRC staff asked DOE to 

provide the inventory of 

each radionuclide disposed 

of in Vault 4 since March of 

2009 (i.e., since 

X-CLC-Z-00027 

[ML102160640] was 

published). 

DOE provided the NRC staff with the document X-CLC-Z-00034, 

“Inventory Determination of PODD/SA Radionuclides in the 

Saltstone Disposal Facility Through 9/30/10” (ML111310276), 

which provided the requested information. NRC staff noted that 

they would appreciate receiving a document with this information 

yearly when it is produced. This issue was resolved during the 

observation. 
4 

NRC Inventory Question Discussion Points

NRC staff asked DOE to 

provide the method used to 

estimate the predicted 

Th-230 in the 2009 PA and 

the method currently being 

used to track the inventory 

of Th-230 disposed of in 

Vault 4. 

This question, which is related to RAI IN-5, was discussed in 

detail during the NRC/DOE public meeting on April 27, 2011 

(ML111950042). This issue was not resolved during the 

observation, but will be addressed by DOE in its response to the 

NRC staff’s second RAI. 

NRC staff asked DOE to 

indicate how the current 

inventory in Vault 4 

compares to the assumed 

inventory in the 2009 PA. 

The NRC staff noted that, 

based on X-CLC-Z-00027 

(ML102160640) and the 

quarterly monitoring 

reports, it appears that the 

I-129 disposed of in Vault 4 

to date exceeds the 

inventory predicted in the 

revised PA. 

NRC staff was concerned that the estimated inventory in the 

2009 PA did not bound the actual inventory, and therefore, the 

PA might not adequately capture dose. NRC staff noted that the 

inventory of I-129 in the 2009 PA (0.28 Ci) was less than the 

reported inventory already disposed in Vault 4 (0.3 Ci), based on 

the website quarterly reports. I-129 is a dose significant 

radionuclide that was identified as a highly radioactive 

radionuclide (HRR) in the 2005 Waste Determination. In 

addition, Vault 4 has not been completely filled yet, so it is 

expected that the final inventory in this vault will be higher. 

DOE indicated the I-129 inventory in Vault 4 does not exceed the 

inventory predicted in the revised PA (SRR-CWDA-2011-00070) 

(ML111310182) based on a reevaluation of the inventory of I-129 

disposed of to date in Vault 4. DOE noted that the preliminary 

concentrations of I-129 reported in the quarterly reports were 

based on estimates determined using the Tank 50 material 

balance and were not based directly on sample results. DOE 

believes that this approach can lead to lead to an overestimation 

of the radionuclide inventories. When DOE compared the 

concentration of I-129 reported in the quarterly reports to the 

Tank 50 sample results, they found that the concentration of 

I-129 reported in the quarterly sample reports was significantly 

higher than the concentration measured in the Tank 50 sample 

during 2009. During this time period, Tank 50 had a relatively 

low volume of liquid in it, and the inputs into Tank 50 primarily 

consisted of inputs from H-canyon. The H-canyon waste stream 

contains I-129 at a concentration that is below the detection limit. 

However, in the materials balance calculation, the concentration 

of I-129 in this waste stream is assumed to be at the detection 

limit. DOE performed a recalculation of the I-129 inventory 

based on the sample results and estimated that the inventory in 

Vault 4 was 0.16 Ci. 
5 

NRC Inventory Question Discussion Points

(cont.) 

NRC staff asked DOE to 

indicate how the current 

inventory in Vault 4 

compares to the assumed 

inventory in the 2009 PA. 

The NRC staff noted that, 

based on X-CLC-Z-00027 

(ML102160640) and the 

quarterly monitoring 

reports, it appears that the 

I-129 disposed of in Vault 4 

to date exceeds the 

inventory predicted in the 

revised PA. 

DOE therefore concluded that the final inventory of I-129 in 

Vault 4 will be bounded by the assumed inventory in the PA. 

DOE stated that the final inventories for each vault will be 

determined using sample results, or best available information, 

once the filling of the vault has been completed. 

The NRC staff believes that the method used in DOE’s 

reevaluation of the inventory of I-129 in Vault 4 seems 

reasonable and this issue was resolved during the observation. 

Based on this reevaluation, the current inventory of I-129 in 

Vault 4 is estimated to be less than the inventory assumed in the 

2009 PA. 

The DOE indicated that they would be providing the NRC with 

the final inventory on an annual basis under monitoring. 

2.1.3 Conclusions and Follow-up Actions:

Questions (1) and (3) were resolved during the observation. Question (2) will be addressed in 

DOE’s response to the NRC staff’s second RAI. No additional issues or concerns were 

identified during the technical discussion on the radionuclide inventory of Vault 4 apart from 

DOE’s continued effort to respond to RAI-2009-02. 

2.2 Technical Discussion – New Research on Long-Term Testing Waste Oxidation and 

Technetium Release: 

2.2.1 Observation Scope:

As noted in Section 3.1.2, “Factor 1 – Oxidation of Saltstone” of the May 2007 monitoring plan, 

saltstone oxidation is considered to be important to compliance with the performance objectives 

primarily because oxidation can lead to increased releases of technetium from the wasteform. 

The release of Tc-99 from the wasteform is an important factor in the compliance with the 

performance objective identified in §61.41, “Protection of the General Population from Releases 

of Radioactivity” and §61.42 “Protection of Individuals from Inadvertent Intrusion.” 

2.2.2 Observation Results:

For greater detail of the discussion that took place during this part of the observation, please 

refer to SRR-CWDA-2011-00071 (ML111310199), the DOE document provided to the NRC 

during the observation. 
6 

Based on the results of recent research (SRNL-STI-2010-00667 and SRNL-STI-2010-00668) 

(ML111310222 and ML111310234), DOE proposed to close Open Issue 2009-1, related to the 

initial chemical reduction of and the Kd value for Tc-99 in saltstone. DOE measured Kd values 

up to ~700 mL/g for Tc to saltstone formulated with 45% slag (nominal concentration) under a 

nitrogen atmosphere with 2% hydrogen gas. NRC staff questioned whether results obtained in 

an atmosphere with 2% hydrogen are applicable to as-emplaced saltstone. In addition, the 

slag-free control samples had similar measured Kd values for Tc-99, which indicates that the 

reduction and sorption of the Tc was not caused by the slag and might have been caused by the 

hydrogen gas instead. DOE indicated that, because the EH of the leachate decreased with 

increasing slag concentrations, they conclude that slag controlled the EH in the reducing 

cementitious materials. 

DOE measured less sorption (Kd of 139 mL/g) of Tc-99 onto cores of saltstone taken from Vault 

4, cell E (SRNL-STI-2010-00667) (ML111310222). DOE hypothesized that the Kd value was 

significantly less than 1000 mL/g because 30-60 ppm oxygen present in the glove box oxidized 

the saltstone. NRC suggested that a complete response to the open issue would indicate 

whether this range of oxygen concentrations could be present in the as-emplaced saltstone 

environment. 

2.2.3 Conclusions and Follow-up Actions:

Because of the NRC staff’s concerns discussed above, Open Issue 2009-1 remains open. No 

additional issues or concerns were identified during the technical discussion regarding 

technetium release and oxidation in the saltstone wasteform. 

2.3 Discussion of Disposal Unit 2 Construction: 

2.3.1 Observation Scope:

The staff’s interest in discussing construction activities of the new disposal cells relates to 

ensuring the integrity of the disposal units and identifying the potential mechanisms of 

contaminant release from the facility. Section 3.1.3, “Hydraulic Isolation of Saltstone,” of the 

May 2007 monitoring plan (NRC, 2007) provides details of the basis for the staff’s intended 

review areas. 

2.3.2 Observation Results:

DOE discussed cell design changes to deal with hydraulic leaks include flush cutting anchor 

bolts, cold cap of type V concrete without anchor bolt, washer and nut mechanical seal, flexible 

coating (see also Hydrotest Results in the table below). DOE provided 

SRR-CWDA-2011-00082 (ML111320032 and ML111320049) which describes the design 

changes made to the new disposal cells. 

2.3.3 Conclusions and Follow-up Actions:

The NRC staff will continue to monitor the construction of the new disposal cells and will 

continue to monitor the cells when they are put into operation. 
7 

2.4 Follow-up Discussion – Topics from Previous Observations: 

2.4.1 Observation Scope:

The staff’s interest in discussing the list of topics in this section relates to multiple sections of the 

May 2007 monitoring plan and also relates to all four of the §61.41 performance objectives. 

Topics discussed included the following: 

• Performance Assessment/Research Activity 

• Open Issues 2007-1, 2007-2, and 2009-1 

• Follow-up Actions 

o Disposal Unit 2 Water Tightness Test Quality Assurance Records 

o Radiological Composition of Inadvertent Transfer Material 

o Status of ARP/MCU Management Control Plan 

o Assess Impact of Anchor Bolt Penetrations in Vault 4 

o Develop Data Related to Impact of Scale on Formed Core Sampling 

Methodology 

• Email Questions from NRC Staff 

o Curing Temperature 

o Saltstone Fracturing 

o Hydrotest Results 

o Vault 4 Floor Performance 

2.4.2 Observation Results:

During the observation, DOE provided a document, SRR-CWDA-2011-00043 (ML111310214), 

which contains many of the details of the discussion provided in this section of the report. This 

document provides good context on the topics below. 

• Performance Assessment/Research Activity 

DOE discussed current and future SDF PA maintenance activities. The current research 

activities include 11 studies on parameters such as the reducing environment, dispersion 

coefficients, degradation mechanisms, closure cap infiltration, and hydrology/geology. 

The planned PA maintenance activities include degradation studies, impacts of waste 

oxidation, vault cracking and attendant transport, and code upgrade. 
8 

• Open Issues 2007-1 and 2007-2 

Open Issues 2007-1 and 2007-2: DOE described plans to continue efforts to determine 

the hydraulic and chemical properties of as-emplaced saltstone grout. DOE indicated it 

would complete analysis of existing saltstone core samples and use formed-core 

sampling to verify the characteristics of as-emplaced saltstone. DOE is developing an 

integrated sampling plan to correlate the properties of laboratory-prepared and asemplaced saltstone samples. DOE indicated it was working to quantify variability in the 

dry feed and the water-to premix ratios. DOE also indicated it is working to test the 

hydraulic and physical properties of saltstone formed with various dry feed compositions 

and cure temperature profiles. Determining the impact of these variations on the 

performance assessment is planned future work. NRC staff indicated that the plans to 

address the open issues sound reasonable. These two issues remain open at this time. 

• Open Issue 2009-1 

The discussion on Open Issue 2009-1 is described in detail in Section 2.2 above. As 

noted above, this issue remains open at this time. 

• Follow-up Action: Disposal Unit 2 Water Tightness Test Quality Assurance Records 

DOE will provide NRC staff with documentation of cell design changes and hydrotesting 

results for review when they are available following the Operational Readiness Review. 

This Follow-up action remains open. 

• Follow-up Action: Radiological Composition of Inadvertent Transfer Material 

During the July 2010 onsite observation, the NRC staff requested information on the 

radionuclide composition of the salt solution that was inadvertently transferred to Vault 4. 

DOE provided document SRR-WSE-2010-00186 (ML111780337) to the NRC on 

October 26, 2010 to respond to this request. 

The inadvertent transfer of approximately 1900 gallons (7192 L) of liquid salt solution to 

Vault 4 occurred on May 19, 2010. This inadvertent transfer was caused by valve 

misalignment during tests of the Salt Feed Tank agitator. Following the inadvertent 

transfer, drain water removal was performed to remove the salt waste. DOE estimates 

that less than 50 gallons (189 L) of this material remained on top of the saltstone 

monolith following this removal. When Saltstone Production Facility was restarted, clean 

grout was added for 15-20 minutes to attempt to encapsulate this remaining liquid. 

Because the radiological inventory disposed of in Vault 4 is determined as the waste is 

transferred from Tank 50, the inventory in the inadvertent transfer material is already 

accounted for in the total inventory disposed of in Vault 4. However, it is useful to 

understand the radiological content of this material because the inventory in the 

inadvertent transfer material may not be encapsulated in the grout well because it was 

not disposed of in the form of grout. The removal of the inadvertently transferred liquid 

to the maximum extent practical and the placement of clean grout when the Saltstone 

Production Facility was restarted likely reduced this concern. 
9 

The material in the inadvertent transfer consisted of salt waste that originated in Tank 50 

plus clean cap drain water returns. A dip sample was taken of the salt waste solution 

remaining in the hopper at the time of the inadvertent transfer. This sample was 

characterized for chemical constituents, but the radiological constituents were not 

characterized. The sample was completely used in the chemical analyses, and no 

sample remains. 

DOE estimated the radiological content of the material in the inadvertent transfer based 

on the radiological composition of the waste from Tank 50 and the estimated dilution 

from the clean cap drain water. The dilution was estimated based on the ratio of sodium 

in the dip sample to the Tank 50 sample. 

NRC staff has reviewed this information and has concluded that while it would have 

been preferable to have actual radiological characterization data for the material in the 

inadvertent transfer, the approach used by DOE to estimate the radiological content of 

this material seems reasonable. Based on the information provided to the NRC in 

SRR-WSE-2010-00186 (ML111780337), the NRC staff considers this action item to be 

closed. 

• Follow-up Action: Status of ARP/MCU Management Control Plan 

During the March 2009 onsite observation (ML091320439), NRC staff identified a followup action for DOE to inform NRC when they exit the ARP/MCU management control 

plan. The basis for this follow-up action was that it was the understanding of the NRC 

staff that the sampling data obtained under the ARP/MCU management control plan was 

going to be used to represent the input from ARP/MCU in the material balance for 

Tank 50. However, during this observation, DOE stated that this sampling information 

was not going to be used as part of the inventory determination in the Tank 50 material 

balance. 

A new follow-up action from this observation is for DOE to clarify to the NRC staff how 

the sampling data obtained under the ARP/MCU management control plan is used and 

how the inventory of radionuclides sent to Tank 50 from ARP/MCU is determined. 

Additionally, DOE raised the concern that tracking long-term items (such as the exit 

strategy for the ARP/MCU management control plan) as follow-up actions, might not be 

the most efficient mechanism. NRC staff stated that a revised monitoring plan will be 

developed following the completion of the TER for the revised PA. In the new monitoring 

plan, NRC staff will generate a list of major changes to the salt waste disposal process 

that they would like to be made aware of, if and when they occur. The transition from 

the ARP/MCU management control plan is an example of what would be included on 

this list, and the follow-up action for DOE to notify NRC when the management control 

plan is exited can be handled in this manner in the future. 

DOE stated that they have no immediate plans to cease operating under ARP/MCU 

Management Control Plan. 
10 

During the onsite observation, DOE staff asked the NRC staff why they were interested 

in the status of the ARP/MCU Management Control Plan. NRC staff stated that the 

basis for their interest in the status of the ARP/MCU Management Control Plan was that 

they believed that the sample results obtained under this plan were used for determining 

the inventory of material transferred from ARP/MCU to Tank 50. NRC staff was also 

interested in knowing when the operations under the ARP/MCU Management Control 

Plan are ceased because DOE had previously indicated samples would be taken less 

frequently once this happened. 

A follow-up discussion on this topic was held by phone on 6/30/11. During this phone 

call, DOE and contractor staff provided additional information to the NRC staff regarding 

the methodology used to determine the inventory transferred to Tank 50 from ARP/MCU. 

DOE contractor staff stated that the purpose of the ARP/MCU samples is to obtain 

information related to safety (such as criticality) and process information and that these 

samples are not used to develop inventory information for the Saltstone Disposal 

Facility. Instead, the inventory information is based on direct analytical measurements 

of the Tank 50 samples, and the materials balance calculations for Tank 50. The 

inventory assumed for the ARP/MCU feed stream in the materials balance is based on 

the expected characterization of the waste in the particular salt batch. This assumed 

characterization may vary between different salt batches. DOE contractor staff stated 

that this assumed characterization is typically an upper bound of the inventory in the 

waste stream. However, in some cases, the assumed inventory can be exceeded. In 

these cases, DOE has a process to determine if it is acceptable to transfer the material 

to Tank 50. 

NRC staff asked how the actual inventory being disposed is known if the inventory 

assumed in materials balance calculations represent an upper bound of the possible 

inventory. DOE contractor staff stated that as the actual Tank 50 sample data is made 

available, the inventory is updated to reflect the sample data, rather than the material 

balance information. DOE offered to provide a demonstration of the spreadsheet used 

for these calculations during the next onsite observation. 

In this case, because the ARP/MCU sample data did not affect the inventory 

determination for the Saltstone Disposal Facility, NRC staff considers this follow-up 

action to be closed. However, NRC staff requests that it be informed when any major 

changes to the Salt Waste processes are made, such as exiting the ARP/MCU 

Management Control Plan, as these types of changes will affect the NRC’s monitoring 

activities. 
11 

• Follow-up Action: Anchor Bolt Penetrations in Vault 4 

During the July 2010 onsite observation, NRC and DOE staffs discussed leakage from 

the vault caused by anchor bolts on the floors of cells 2A and 2B during the hydrotests 

(no waste involved). NRC staff raised a concern with the integrity of Vault 1 and 4 floors 

based on the presence of a similar drain system and anchor bolts. NRC staff suggested 

that direct evidence of leakage could be determined by horizontal soil cores under Vaults 

1 and 4. DOE contractor staff described the progress that has been made towards 

addressing this follow-up action to date. DOE has visually inspected several anchor 

bolts locations in cells B and H of Vault 4, which are empty, and did not see any 

evidence of cracking on the vault floor surface. DOE also discussed historical, semiannual monitoring well data that does not indicate that there have been releases from 

Vault 4. The potential effects of bolt penetrations will be mitigated in the FDCs, and the 

need for bolts (to anchor cable brace) will be eliminated in the new design. 

This follow-up action remains open pending the response to the above concern and the 

completion of the work DOE is performing on this follow-up action. The NRC staff will 

continue to review documentation regarding this follow-up action as it becomes 

available. 

• Follow-up Action: Impact of Scale on Core Sampling Methodology 

During the July 2010 onsite observation, NRC and DOE staffs discussed proposed 

future saltstone core sampling techniques. Alternate methods were discussed and each 

had its strengths and weaknesses. DOE presented information on an in-situ sampling 

technique essentially using embedded pipes, for which they tested the force required to 

remove the sampling device. NRC expressed concern that the sampling device may 

allow less disruption of the sample, however the sampling device may change the in-situ 

conditions of the wasteform such that the sample is not representative. The NRC stated 

that when its contractor conducted experiments to test the properties of large-scale 

samples, scale effects were evident in the results. This highlights the importance of 

measuring properties of representative samples at appropriate scale. 

DOE is developing a formed-core sampling methodology to minimize the disruption to 

core samples that was discussed in the July 2010 onsite observation. NRC staff has 

commented that formed-core samples may not be representative of in-situ conditions, 

but it will continue to review core-sampling approaches and results. 

DOE will move forward with formed-core sampling technology. Operational 

considerations such as worker exposure and logistics will be considered in sampling 

plan. This follow-up action remains open pending the response to the completion of the 

work DOE is performing on the impact of scale on core sampling methodology. 
12 

Discussion Topic NRC Question Discussion Po

Cure Temperatures and Impact of Aluminate Concentration (October 2007 Observation) 

The NRC onsite observation report for the October 2007 discussed the use of thermocouples within the vault and saltstone to monitor temperatures. At that point, the maximum observed temperature was ~50oC. 

What temperatures have been monitored since 2007 and what is the anticipated curing temperature based on the increase in aluminate concentration? 

NRC staff inquired about the cure temgrout as recent research has indicated on the hydraulic properties of saltstonA hydraulic conductivity of 8.6E-7 cm/saltstone grout simulant that was cure

than the value assumed in the PA by mDOE stated that cure temperature procompiled and will be considered in futdiscussed the importance of mimicking practicable, including cure temperatur

Saltstone Fracturing (March 2009 Observation) 

NRC staff noted that the saltstone fractures do not appear to be extensive, but that conclusion was hindered by lack of scale and a limited survey area and that DOE planned to do additional surveys in the future. Have there been any recent saltstone surveys in addition to Vault 4, Cell G? 

During the March 2009 observation, psurvey that showed fractures on the sin Cell G of Vault 4. The survey area since developed a video surveillance pfracturing of the saltstone surface. ThDOE and evaluated with respect to the the video and analysis as they becom

Hydrotest Results (April 2010 Observation) 

What are the details of the recent hydrotests results for each cell (e.g., hydraulic head, test duration, observation procedures, observations)? 

DOE stated that the hydrostatic testing following the design changes showed The follow-up testing consisted of a mhydrotest. The new test consisted of a for 132 hours. The NRC staff conside

Vault 4 Floor (July 2010 Observation) 

Vault 4 Floor - NRC staff asked that DOE look into characterizing the Vault 4 floor (or the material under the floor) to see if the floor in Vault 4 had cracked. Has there been any progress on this topic? 

The response to this email question wup Action: Anchor Bolt Penetrations in follow-up action remains open pending question and the completion of the wothis follow-up action. 
13 

2.4.3 Conclusions and Follow-up Actions:

No new issues or concerns were identified during the technical discussion; however, multiple 

follow-up actions were identified during the discussion. Below is a list of items discussed during 

this portion of the observation. 

Performance Assessment/Research Activity - NRC staff would like to know the results of the 

current research activities regarding the current and future SDF PA maintenance activities. This 

is not a follow-up action; however, the staff maintains an interest in PA maintenance activities 

and will continue discussions with the DOE leading up to its upcoming revision to the 2007 NRC 

monitoring plan for the Saltstone Disposal Facility. 

Open Issues 2007-1 and 2007-2 - NRC staff indicated that DOE’s plans to address the open 

issues sound reasonable and will review the results of DOE’s planned efforts. Currently, the 

two issues remain open. 

Follow-up Action: Disposal Unit 2 Water Tightness Test Quality Assurance Records - 

DOE stated they would provide the NRC staff documentation of the design changes and 

hydrotesting results of the new disposal cells. NRC will review these documents when 

provided. This follow-up action remains open. 

Follow-up Action: Radiological Composition of Inadvertent Transfer Material - Based on 

the information provided to the NRC in SRR-WSE-2010-00186 (ML111780337) provided to the 

NRC on October 26, 2010, the NRC staff considers this action item to be closed. 

Follow-up Action: Status of ARP/MCU Management Control Plan - The NRC would like 

DOE to clarify how the sampling data obtained under the ARP/MCU management control plan is 

used and how the inventory of radionuclides sent to Tank 50 from ARP/MCU is determined. 

This is a new follow-up action from this observation. 

In response to the DOE concern that tracking of long-term items as follow-up actions might not 

be the most efficient mechanism, NRC staff stated that the new monitoring plan will contain a 

list of major changes to the salt waste disposal process that they would like to be made aware 

of, if and when they occur. 

DOE offered to provide a demonstration of the spreadsheet used for these inventory-updating 

calculations during the next onsite observation. This is not a follow-up action; however, the 

NRC would like to observe this demonstration in the future. The NRC makes note that this will 

be a future observation activity. 

Because the ARP/MCU sample data does not affect the inventory determination for the 

Saltstone Disposal Facility, NRC staff considers this follow-up action, which was created during 

this observation, to be closed.
14 

Follow-up Action: Anchor Bolt Penetrations in Vault 4 - Because of the pending response to 

the NRC concern regarding the integrity of Vault 1 and 4 floors based on the presence of a 

similar drain system and anchor bolts and the pending completion of the work DOE is 

performing on the impacts of anchor bolt penetrations, this follow-up action remains open. 

Follow-up Action: Impact of Scale on Core Sampling Methodology - NRC staff will 

continue to review core-sampling approaches and results, and DOE will move forward with 

formed-core sampling technology with consideration of the discussed exposure and logistical 

techniques when developing the sampling plan. 

Cure Temperatures and Impact of Aluminate Concentration - NRC staff will review the cure 

temperature profiles for saltstone when DOE compiles them following future testing. 

Saltstone Fracturing - NRC will review saltstone surface fracturing surveillance captured by 

DOE’s recently developed video surveillance program as they become available. 

Hydrotest Results - DOE stated that the hydrostatic testing of the new disposal cells, following 

the design changes showed no evidence of leaking. The follow-up testing consisted of a 

modified version of the earlier hydrotest. The new test consisted of a 12-foot head differential 

for 132 hours. The NRC staff considers this follow-up action to be closed. 

3.0 OVERALL CONCLUSIONS AND FOLLOW-UP ACTIONS: 

3.1 Technical Discussion – Saltstone Radionuclide Inventory: 

Of the three questions discussed during this portion of the observation, only question (2) 

remains unanswered. Question (2) will be addressed in DOE’s response to the NRC staff’s 

second RAI (RAI-2009-02). No additional issues or concerns were identified during the 

technical discussion on the radionuclide inventory of Vault 4 apart from DOE’s continued effort 

to respond to RAI-2009-02. The NRC continues to have reasonable assurance that the 

10 CFR Part 61 performance objectives can be met provided that key assumptions made in the 

waste determination prove to be correct. 

3.2 Technical Discussion – New Research on Long-Term Testing Waste Oxidation and 

Technetium Release: 

Because of the NRC staff’s concerns discussed above, Open Issue 2009-1 remains open. No 

additional issues or concerns were identified during the technical discussion regarding 

technetium release and oxidation in the saltstone wasteform. The NRC continues to have 

reasonable assurance that the 10 CFR Part 61 performance objectives can be met provided 

that key assumptions made in the waste determination prove to be correct. 

3.3 Discussion of Disposal Unit 2 Construction: 

The NRC staff will continue to monitor the construction of the new disposal cells and will 

continue to monitor the cells when they are put into operation. 
15 

3.4 Follow-up Discussion – Topics from Previous Observations: 

The table below summarizes the status of each of the discussion topics. Each topic is classified 

as being open, closed, or a future topic for discussion. The following terms are used to classify 

the topics. 

Remains Open: The NRC is still awaiting action on the part of DOE, or results from 

a recent action taken by DOE. Further discussion will need to 

take place before the NRC can close the topic. 

Topic Closed: The specific inquiry posed by the NRC has been fully responded 

to by DOE. 

Future Consideration: The specific inquiry posed by the NRC has been discussed and 

DOE has stated a path forward that seems acceptable to the 

NRC. The item is not open because the DOE plans to address 

the topic. The item is not closed because the NRC is interested in 

the results of the analysis being performed by DOE. 

Discussion Topic Remains 

Open 

Topic 

Closed 

Future 

Consideration

PA/Research Activity X 

Open Issues 2007-1 and 2007-2 X 

Follow-up Action: Disposal Unit 2 Water Tightness 

Test Quality Assurance Records X 

Follow-up Action: Radiological Composition of 

Inadvertent Transfer Material X 

Follow-up Action: Status of ARP/MCU 

Management Control Plan X X 

Follow-up Action: Anchor Bolt Penetrations in 

Vault 4 X 

Follow-up Action: Impact of Scale on Core 

Sampling Methodology X 

Cure Temperatures and Impact of Aluminate 

Concentration X 

Saltstone Fracturing X 

Hydrotest Results X 

Vault 4 Floor X 
16 

4.0 PARTICIPANTS: 

U.S. NRC

George Alexander 

Christepher McKenney 

Andrew Persinko 

Karen Pinkston 

Christianne Ridge 

James Shaffner (for Nishka Devaser) 

U.S. DOE-SR

Sherri Ross 

Patricia Suggs 

SRR

Ginger Dickert 

F. Malcolm Smith 

Aaron Staub 

Steve Thomas 

Rebecca Freeman 

U.S. DOE

Linda Suttora 

5.0 REFERENCES: 

U.S. Department of Energy (DOE). CBU-PIT-2005-0146, “Saltstone Performance Objective 

Demonstration Document.” Westinghouse Savannah River Company. June 2005. 

–––––. DOE-WD-2005-001, “Basis for Section 3116 Determination Salt Waste Disposal at the 

Savannah River Site.” Washington, DC: DOE. January 2006. 

–––––. SRR-CWDA-2009-00017, Performance Assessment for the Saltstone Disposal Facility 

at the Savannah River Site, Savannah River Site, Aiken, SC, October 29, 2009 (ADAMS 

Accession No. ML101590008). October 2009. 

U.S. Nuclear Regulatory Commission (NRC). “Technical Evaluation Report for Draft Waste 

Determination for Salt Waste Disposal.” Letter from L. Camper to C. Anderson, DOE. 

December 28, 2005. (Agencywide Documents Access and Management System (ADAMS) 

Accession No. ML053010225). 

–––––. “U.S. Nuclear Regulatory Commission Plan for Monitoring the U.S. Department of 

Energy Salt Waste Disposal at the Savannah River Site in Accordance with the National 

Defense Authorization Act for Fiscal Year 2005.” Washington, DC: NRC. May 3, 2007. 

(ADAMS Accession No. ML070730363). 

–––––. “U.S. Nuclear Regulatory Commission March 24-28, 2008 Onsite Observation Report 

for the Savannah River Site Saltstone Facility.” June 5, 2008 (ADAMS Accession No. 

ML081290367). 

–––––. “U.S. Nuclear Regulatory Commission March 25-26, 2009 Onsite Observation Report 

for the Savannah River Site Saltstone Facility.” May 22, 2009 (ADAMS Accession No. 

ML091320439). 

–––––. “U.S. Nuclear Regulatory Commission Request for Additional Information on the 2009 

Performance Assessment for the Saltstone Disposal Facility at the Savannah River Site.” 

March 31, 2010a (ADAMS Accession Number ML100820097). 

–––––. “U.S. Nuclear Regulatory Commission April 19, 2009 Onsite Observation Report for the 

Savannah River Site Saltstone Facility.” July 7, 2010b (ADAMS Accession No. ML101460044).