September 28, 2015 

Ms. Jean Ridley, Director 

Waste Disposition Programs Division 

U.S. Department of Energy 

Savannah River Operations Office 

P.O. Box A 

Aiken, SC 29802 

SUBJECT: THE U.S. NUCLEAR REGULATORY COMMISSION JULY 7 – 8, 2015, ONSITE 

OBSERVATION VISIT REPORT FOR THE SAVANNAH RIVER SITE SALTSTONE 

DISPOSAL FACILITY (DOCKET NO. PROJ0734) 

Dear Ms. Ridley: 

The enclosed onsite observation visit (OOV) report describes the U.S. Nuclear Regulatory 

Commission (NRC) OOV on July 7–8, 2015, at the Savannah River Site (SRS) Saltstone 

Disposal Facility (SDF). That OOV was conducted in accordance with Section 3116(b) of the 

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

requires the NRC to monitor certain disposal actions taken by the U.S. Department of Energy 

(DOE) for the purpose of assessing compliance with the performance objectives set out in 

Title 10 of the Code of Federal Regulations (CFR) Part 61, Subpart C. That was the 

seventeenth SDF OOV since the NRC began monitoring the DOE SDF disposal actions under 

NDAA Section 3116(b) in October 2007. 

The main activities conducted during the July 2015 SDF OOV were tours and technical 

discussions. A tour focused on Saltstone Disposal Structure (SDS) 2A, SDS 2B, SDS 3A, 

SDS 3B, SDS 4, SDS 5A, SDS 5B, and construction of SDS 6. A tour and technical discussion 

focused on groundwater monitoring. The other technical discussions focused on: (i) DOE SDF 

operating status and disposal structure status; (ii) routine documentation and Follow-Up Action 

Items from previous NRC monitoring activities; (iii) groundwater monitoring; (iv) DOE research 

update; (v) DOE collection of core samples; (vi) GoldSim Modeling; and (vii) NRC Request for 

Additional Information Questions (RAIs) on the DOE FY 2014 Special Analysis document. 

Those OOV activities were consistent with the activities described in the NRC Observation 

Guidance Memorandum for the July 2015 SRS SDF OOV (dated June 8, 2015) [available via 

the NRC Agencywide Documents Access and Management System (ADAMS) at Accession 

No. ML15148A388]. That Guidance Memorandum was developed using the SDF Monitoring 

Plan, Rev. 1 (dated September 2013) [ADAMS Accession No. ML13100A113]. The SDF 

Monitoring Plan contains the monitoring areas and monitoring factors, which describe how the 

NRC will monitor the DOE SDF disposal actions to assess compliance with the performance 

objectives. All previous NRC concerns have been rolled into the monitoring factors in the 2013 

SDF Monitoring Plan. 

 
J. Ridley - 2 - 

The NRC does not expect to close any of the 73 SDF monitoring factors (specific to a specific 

performance objective) or change the NRC 2012 Technical Evaluation Report (TER) overall 

conclusions as a result of the July 2015 OOV. There were no SDF Open Issues before the 

July 2015 OOV and there were no SDF Open Issues identified during the July 2015 OOV. 

Thus, there are currently no SDF Open Issues. 

The NRC does expect to open and close Follow-Up Action Items during OOVs and clarification 

teleconference calls. Most of those Follow-Up Action Items are specific short-term actions to be 

performed by the NRC or the DOE. Usually, most of those Follow-Up Action Items are closed 

before the next OOV or clarification teleconference call. 

A main focus of the NRC staff performing an OOV under NDAA monitoring at the SDF is both 

the NRC 2012 TER [ADAMS Accession No. ML121020140] and the NRC Type-IV Letter of 

Concern [ADAMS Accession No. ML120650576], which were both issued on April 30, 2012, and 

both pertain to waste disposal at the SRS SDF. The NRC 2012 TER concluded that the NRC 

did not have reasonable assurance that salt waste disposal at the SDF met the performance 

objective of §61.41. The NRC Type-IV Letter of Concern formally communicated the NRC 

concerns to both the DOE and the South Carolina Department of Health and Environmental 

Control (i.e., South Carolina regulator of SRS). The DOE provided responses to the NRC 

Type-IV Letter to the NRC in multiple submittals. Those submittals included an updated 

technetium-99 (Tc-99) inventory projection for the constructed disposal structures similar in 

design to SDS 2A (i.e., SDS 2A, SDS 2B, SDS 3A, SDS 3B, SDS 5A, SDS 5B) and information 

about the DOE Case K and Case K1 uncertainty and sensitivity analyses. 

In August 2012, the NRC issued a letter of acknowledgement to the DOE [ADAMS Accession 

No. ML12213A447], which included that: “... the NRC staff concludes that a Type-II Letter to 

the U.S. Congress is not needed at this time.” Based on the NRC TER and the DOE revised 

Tc-99 inventory, the NRC staff determined that, if the DOE new projected Tc-99 inventory for 

the constructed disposal structures was correct, then it was unlikely that the salt waste disposal 

into those disposal structures would cause an off-site peak dose exceeding the requirements of 

§61.41 (i.e., 0.25 mSv/yr (25 mrem/yr)). 

The NRC and the DOE continue to work in the monitoring process to resolve all outstanding 

concerns that led to issuance of the NRC Type-IV Letter of Concern. In accordance with the 

requirements of NDAA Section 3116(b), the NRC will continue to monitor the DOE disposal 

actions at SRS SDF. 
J. Ridley - 3 - 

If you have any questions or need additional information regarding this onsite observation visit 

report, then please contact Mr. Harry Felsher of my staff at Harry Felsher@nrc.gov or at 

(301) 415-6559. 

Sincerely, 

 /RA/

Andrew Persinko, Deputy Director 

Division of Decommissioning, Uranium Recovery, 

 and Waste Programs 

Office of Nuclear Material Safety 

 and Safeguards 

Enclosure: 

NRC Onsite Observation Visit Report 

cc w /enclosure: 

WIR Service List 

WIR e-mail Contacts List 

 
J. Ridley - 3 - 

If you have any questions or need additional information regarding this onsite observation visit 

report, then please contact Mr. Harry Felsher of my staff at Harry Felsher@nrc.gov or at 

(301) 415-6559. 

Sincerely, 

 /RA/

Andrew Persinko, Deputy Director 

Division of Decommissioning, Uranium Recovery, 

 and Waste Programs 

Office of Nuclear Material Safety 

 and Safeguards 

Enclosure: 

NRC Onsite Observation Visit Report 

cc w /enclosure: 

WIR Service List 

WIR e-mail Contacts List 

DISTRIBUTION: 

GAlexander HArlt KPinkston TBrimfield 

MRoberts/Region I MFerdas/Region I 

ADAMS Accession No. ML15236A299 

OFFFICE PM Tech Lead LA PAB:BC LLWB:BC DUWP:DDD 

NAME HFelsher CRidge 

(by e-mail) 

TMoon 

(by e-mail) CMcKenney MHeath APersinko 

DATE 08/24/15 08/26/15 08/27/15 09/01/15 9/23/15 9/28/15 

OFFICIAL RECORD COPY
Glenn Carroll, Coordinator 

Nuclear Watch South 

P.O. Box 8574 

Atlanta, GA 31106 

Thomas Saporito, Executive Director 

P.O. Box 8413 

Jupiter, FL 33468 

Tom Clements, Member 

Friends of the Earth 

1112 Florence Street 

Columbia, SC 29201 

Justin Koone 

Saltstone Project Manager 

Mining and Solid Waste Permitting Section 

Bureau of Land and Waste Management 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1208 

Jim Hardeman, Manager 

Environmental Radiation Program 

Environmental Protection Division 

Georgia Department of Natural Resources 

4220 International Parkway, Suite 100 

Atlanta, GA 30354 

Ruth Thomas 

354 Woodland Drive 

Columbus, SC 28722 

Karen Patterson, Environmental 

Appointment 

Governors' Nuclear Advisory Council 

 and Tetra Tech NUS 

900 Trail Road 

Aiken, SC 29803-5297 

Dianne Valentin, President 

Board of Directors 

Georgia Women's Action for New Directions 

250 Georgia Avenue, SE 

Suite 205 

Atlanta, GA 30312 

Robert H. Pope 

Senior Remedial Project Manager 

U.S. Environmental Protection Agency 

Region 4, Superfund Division 

Federal Facilities Branch, Waste Division 

61 Forsyth Street 

Atlanta, GA 30303 

Shelly Wilson 

Federal Facilities Liaison 

Environmental Quality Control 

 Administration 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1708 

Jon Richards, Remedial Project Manager 

U.S. Environmental Protection Agency 

Region 4, Superfund Division 

Federal Facilities Branch, Waste Division 

61 Forsyth Street 

Atlanta, GA 30303 
Enclosure 

U.S. NUCLEAR REGULATORY COMMISSION 

JULY 7 – 8, 2015, ONSITE OBSERVATION VISIT REPORT FOR 

THE SAVANNAH RIVER SITE SALTSTONE DISPOAL FACILITY 

EXECUTIVE SUMMARY: 

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

observation visit (OOV) to the Saltstone Disposal Facility (SDF) at the Savannah River Site 

(SRS) on July 7 – 8, 2015 (SDF Observation 2015-02). That was the second SDF OOV in 

Calendar Year (CY) 2015. On every OOV to SRS, the NRC is focused on assessing 

compliance with four performance objectives in Title 10 of the Code of Federal Regulations

(CFR) Part 61, Subpart C: (1) protection of the general population from releases of radioactivity 

(§61.41), (2) protection of individuals from inadvertent intrusion (§61.42), (3) protection of 

individuals during operations (§61.43), and (4) stability of the disposal site after closure 

(§61.44). Please see the attachment to this OOV report for the detailed technical information 

from this OOV. 

For this OOV, the NRC focused on the monitoring areas and monitoring factors in the SDF 

Monitoring Plan, Rev. 1 (September 2013). This is the third SDF OOV under SDF Monitoring 

Plan, Rev. 1. All NRC concerns prior to the 2013 SDF Monitoring Plan were rolled into the 

monitoring factors in the 2013 SDF Monitoring Plan. The NRC performs monitoring activities in 

coordination with South Carolina, therefore the South Carolina Department of Health and 

Environmental Control (SCDHEC) staff also participated in the OOV and received the same 

information from the U.S. Department of Energy (DOE) as the NRC received from the DOE 

during the OOV. 

As described in the Observation Guidance Memorandum for the OOV, The main activities 

conducted were tours and technical discussions between the DOE (i.e., includes DOE 

contractors throughout this OOV report), the NRC, and the SCDHEC. A tour focused on 

SDS 2A, SDS 2B, SDS 3A, SDS 3B, SDS 4, SDS 5A, SDS 5B, and construction of SDS 6. A 

tour and technical discussion focused on groundwater monitoring. The other technical 

discussions focused on: (i) DOE SDF operating status and disposal structure status; (ii) routine 

documentation and Follow-Up Action Items from previous NRC monitoring activities; 

(iii) groundwater monitoring; (iv) DOE research update; (v) DOE collection of core samples; 

(vi) GoldSim Modeling; and (vii) NRC Request for Additional Information Questions (RAIs) on 

DOE FY 2014 Special Analysis document. This OOV report provides a description of the 

activities during the OOV, including observations made by the NRC. 

The NRC does not expect to close any of the 73 SDF monitoring factors (specific to a specific 

performance objective) or change the NRC 2012 Technical Evaluation Report (TER) overall 

conclusions as a result of the OOV. There were no SDF Open Issues before the OOV and 

there were no SDF Open Issues identified during the OOV. Thus, there are currently no SDF 

Open Issues. The NRC and the DOE continue to work in the monitoring process to resolve all 

outstanding concerns that led to issuance of the NRC Type-IV Letter of Concern. 

The NRC received the updated DOE presentation (SRR-CWDA-2015-00086, Rev. 1) that 

pertained to the activities during the OOV. That DOE presentation is accessible via the NRC 
- 2 - 

Agencywide Documents Access and Management System (ADAMS), via Accession 

No. ML15223B096. 

1.0 BACKGROUND:

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

authorizes the 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. NDAA Section 3116(b) requires the NRC to monitor the DOE disposal actions to 

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

On March 31, 2005, the DOE submitted to the NRC the Draft Section 3116 Determination for 

Salt Waste Disposal Savannah River Site (DOE-WD-2005-001, Rev. 0) [ADAMS Accession 

No. ML051020072] to demonstrate compliance with the NDAA criteria, including demonstration 

of compliance with the performance objectives in 10 CFR Part 61, Subpart C. In its consultation 

role, the NRC staff reviewed the draft waste determination. In the NRC TER issued in 

December 2005 [ADAMS Accession No. ML053010225], the NRC documented the results of its 

review and concluded that there was reasonable assurance that the applicable criteria of NDAA 

could be met, provided certain assumptions made in the DOE analyses were verified via 

monitoring. Taking into consideration the assumptions, conclusions, and recommendations in 

the NRC 2005 TER, the DOE issued the final waste determination in January 2006 (DOE-WD2005-001, Rev. 1) [ADAMS Accession No. ML102850319]. 

The DOE submitted a revised Performance Assessment (PA) to the NRC in 2009 (SRR-CWDA2009-00017) [ADAMS Accession No. ML101590008]. The NRC staff reviewed SRR-CWDA2009-00017, including holding public meetings, sending requests for additional information, and 

reviewing the DOE responses. On April 30, 2012, the NRC issued both a new TER [ADAMS 

Accession No. ML121020140] and a Type-IV Letter of Concern [ADAMS Accession No. 

ML120650576]. In the 2012 TER, the NRC concluded that it did not have reasonable 

assurance that the DOE salt waste disposal at the SDF met the performance objectives in 

10 CFR Part 61, specifically 10 CFR 61.41. The NRC Type-IV Letter of Concern formally 

communicated the NRC concerns to both the DOE and the SCDHEC (i.e., South Carolina 

regulator of SRS). 

In July 2012, the DOE responded to the NRC Type-IV Letter in multiple submittals. Those 

submittals [ADAMS Accession Nos. ML12198A258 and ML12215A081] included an updated 

technetium-99 (Tc-99) inventory projection for the constructed disposal structures similar in 

design to Saltstone Disposal Structure (SDS) 2A (i.e., SDS 2A, SDS 2B, SDS 3A, SDS 3B, 

SDS 5A, SDS 5B) and information about the DOE Case K and Case K1 uncertainty and 

sensitivity analyses. In August 2012, the NRC issued a letter of acknowledgement to the DOE, 

which included that: “... the NRC staff concludes that a Type-II Letter to the U.S. Congress is 

not needed at this time.” Based on the NRC 2012 TER and the DOE revised Tc-99 inventory, 

the NRC staff determined that, if the DOE new projected Tc-99 inventory for the constructed 

disposal structures was correct, then it was unlikely that the salt waste disposal into those 

disposal structures would cause an off-site peak dose exceeding the requirements of §61.41 

(i.e., 0.25 mSv/yr (25 mrem/yr)). 
- 3 - 

To carry out its monitoring responsibility under NDAA Section 3116(b), the NRC, in coordination 

with SCDHEC, performs three activities: (1) technical reviews, (2) OOVs, and (3) data reviews. 

Those activities focus on both: (1) key modeling assumptions identified in the NRC SDF 

Monitoring Plan, Rev. 1; and (2) the DOE disposal actions. Specifically, technical reviews 

generally focus on reviewing information generated to provide support for key assumptions that 

the DOE made in the SDF PA or supplements, such as special analysis documents. OOVs 

generally focus on either: (1) observing the collection of data and reviewing the data to assess 

consistency with assumptions made in the SDF final Waste Determination; or (2) observing key 

disposal or closure activities related to technical review areas. Data reviews generally focus on 

supplementing technical reviews by focusing on monitoring data that may indicate future system 

performance or reviewing records or reports that can be used to directly assess compliance with 

the performance objectives. 

2.0 NRC ONSITE OBSERVATION VISIT ACTIVITIES:

On June 8, 2015, the NRC issued the Observation Guidance [Accession No. ML15148A388] for 

the July 7 – 8, 2015, OOV, SDF Observation 2015-02. An Observation Guidance is a plan for 

what NRC expects to cover during an OOV, which may be changed based on what happens 

during the OOV. Please see the attachment to this OOV report for the detailed technical 

information about this OOV. 

The OOV began with a short briefing on the agenda presented by the DOE contractor, 

Savannah River Remediation (SRR) that was attended by representatives from the DOE, the 

NRC, and the SCDHEC. Afterwards, there were welcoming remarks and introductions. The 

rest of the OOV consisted of tours and technical discussions. A tour focused on SDS 2A, 

SDS 2B, SDS 3A, SDS 3B, SDS 4, SDS 5A, SDS 5B, and construction of SDS 6. A tour and 

technical discussion focused on groundwater monitoring. The other technical discussions 

focused on: (i) DOE SDF operating status and disposal structure status; (ii) routine 

documentation and Follow-Up Action Items from previous NRC monitoring activities; 

(iii) groundwater monitoring; (iv) DOE research update; (v) DOE collection of core samples; 

(vi) GoldSim Modeling; and (vii) NRC RAIs on DOE FY 2014 Special Analysis document. 

2.1 Technical Discussion – DOE SDF Operating Status and Disposal Structure Status: 

2.1.1 Observation Scope: 

The technical discussion supported the NRC monitoring of the DOE disposal actions to assess 

compliance with 10 CFR 61.41, 10 CFR 61.42 and 10 CFR 61.43. The technical discussion 

was most relevant to the following monitoring areas (MAs) and monitoring factors (MFs) in SDF 

Monitoring Plan, Rev. 1: 

• MA1 (Inventory): 

o MF 1.01 (Inventory in Disposal Structures) 

• MA 11 (Radiation Protection Program): 

o MF 11.01 (Dose to Individuals During Operations) 

 
- 4 - 

2.1.2 Observation Results: 

The DOE presented an overview of the SDF operating status and disposal structure status 

(SRR-CWDA-2015-00086) [ADAMS Accession No. ML15223B096]. The key points from the 

presentation and technical discussion were: 

• Technetium (Tc) concentrations will be higher in Salt Batch 8 than in Salt Batch 7. 

• Higher than expected mercury (Hg) concentrations were found and the DOE speculated 

that it was because waste from the tanks in the H-Tank Farm have approximately 

40 times higher Hg concentrations than tanks in the F-Tank Farm. 

• There was a reduction in the fill height limit for the 150-foot disposal structures from 

21.5 feet to 19.0 feet because of concerns about dimethyl mercury and the change was 

expected to be a temporary condition pending further analysis. 

• The NRC staff was interested in the inventory of Tc in SDS 5B. 

2.1.3 Conclusions and Follow-up Action Items: 

The NRC staff will continue to monitor the DOE SDF activities. The following Follow-Up Action 

Items resulted from the technical discussion. 

• The DOE will provide the NRC with information on SDS 3A, SDS 3B, SDS 5A, and 

SDS 5B fill height restrictions related to resolution of mercury Potential Inadequacy in 

the Safety Analysis. 

• The DOE will provide the NRC with the document “SRR-CWDA-2014-00124, 

Determination of SDF Inventories through 9/30/2014.” 

• The DOE will provide the NRC with the inventory in SDS 5B through 09/30/2015. 

2.2 Technical Discussion – Routine Documentation and Follow-Up Action Items from 

Previous NRC Monitoring Activities: 

2.2.1 Observation Scope: 

The technical discussion supported the NRC monitoring of the DOE disposal actions to assess 

compliance with 10 CFR 61.41 and 10 CFR 61.42. The technical discussion was most relevant 

to the following MAs and MFs in SDF Monitoring Plan, Rev. 1: 

• MA1 (Inventory): 

o MF 1.01 (Inventory in Disposal Structures) 

• MA 8 (Environmental Monitoring): 

o MF 8.02 (Groundwater Monitoring) 
- 5 - 

2.2.2 Observation Results: 

The key points from the technical discussion were: 

• The DOE provided the status summary of routine documents, including about inventory, 

provided by the DOE to the NRC. 

• The NRC and the DOE agreed that at the start of SDF Observation 2015-02 there were 

two open Follow-Up Action Items and the DOE provided the information, including items 

about groundwater monitoring, to close out those two items during the OOV. 

2.2.3 Conclusions and Follow-up Action Items:

The NRC staff will continue to monitor the DOE SDF activities. There were no Follow-Up Action 

Items that resulted from the technical discussion. 

2.3 Tour – SDS 2A, SDS 2B, SDS 3A, SDS 3B, SDS 4, SDS 5A, SDS 5B, and 

Construction of SDS 6: 

2.3.1 Observation Scope: 

The tour supported the NRC monitoring of the DOE disposal actions to assess compliance with 

10 CFR 61.41 and 10 CFR 61.42. The tour was most relevant to the following MA and MFs in 

SDF Monitoring Plan, Rev. 1: 

• MA 6 (Disposal Structure Performance): 

o MF 6.03 (Performance of Disposal Structure Roofs and HDPE/GCL Layers) 

o MF 6.04 (Disposal Structure Concrete Fracturing) 

o MF 6.05 (Integrity of Non-Cementitious Materials) 

2.3.2 Observation Results: 

The key points from the tour were: 

• The DOE discussion on the features of the drain system on SDS 4 and historical leak 

sites in SDS 4. 

• Observing the application of pre-stressing wires in the construction of SDS 6 from an 

observation platform overlooking SDS 6. 

2.3.3 Conclusions and Follow-up Action Items:

The NRC staff will continue to monitor the DOE SDF activities. The following Follow-Up Action 

Item resulted from the tour: 
- 6 - 

• The DOE will provide the NRC with photographs from the tour of the SDF disposal 

structures on 07/07/2015. 

2.4 Tour and Technical Discussion – Groundwater Monitoring: 

2.4.1 Observation Scope: 

The tour and technical discussion supported the NRC monitoring of the DOE disposal actions to 

assess compliance with 10 CFR 61.41 and 10 CFR 61.42. The tour and technical discussion 

was most relevant to the following MA and MFs in SDF Monitoring Plan, Rev. 1: 

• MA 8 (Environmental Monitoring): 

o MF 8.01 (Leak Detection) 

o MF 8.02 (Groundwater Monitoring) 

2.4.2 Observation Results: 

The key points from the tour and technical discussion were: 

• The challenge of the DOE modeling the area’s groundwater model in order to compare 

with the observed concentrations in Well ZBG-2. 

• The closure of Well ZBG-2 and replacement by the two new nearby Well ZBG-2C and 

Well ZBG-2D. 

• The DOE 2015 mid-year groundwater monitoring report will include the last data from 

Well ZBG-2 and the first data from Well ZBG-2C. The first data from Well ZBG-2D will 

be in the DOE final 2015 annual groundwater monitoring report. 

• Data from Cone Penetrometer Tests and Direct Push Technology will be available in the 

DOE final 2015 annual groundwater monitoring report. The NRC staff expects that the 

data will provide useful information about the Conceptual Site Model for contaminant 

transport in the upper and lower zones of the Upper Three Runs Aquifer. 

• The SCDHEC concern that contaminants will migrate from the unlined sedimentation 

basins north of SDS 4 into the groundwater. The NRC staff will pursue the SCDHEC 

concern with DOE as part of our normal monitoring activities. 

• The NRC and SCDHEC issues about the three production wells being installed in the 

Z Area in preparation for the hydrotest of SDS 6. 

• The NRC was interested in information about tanks that the SDS 6 construction 

company built in Syracuse, New York. 

• The NRC was interested in the future revised DOE General Separations Area 

groundwater model. 
- 7 - 

2.4.3 Conclusions and Follow-up Action Items:

The NRC staff will continue to monitor the DOE SDF activities. The following Follow-Up Action 

Items resulted from the tour and technical discussion: 

• The DOE will provide the NRC with the 2015 mid-year groundwater monitoring report, 

when available. 

• The DOE will provide the NRC information available on production well (SDS 6) depth 

and potential impact on surface settlement. 

• The DOE will provide to the NRC information about water tanks that the SDS 6 

construction company built in Syracuse, New York and used as a model for SDS 6. 

2.5 Technical Discussion – DOE Research Update: 

2.5.1 Observation Scope: 

The technical discussion supported the NRC monitoring of the DOE disposal actions to assess 

compliance with 10 CFR 61.41 and 10 CFR 61.42. The discussion was most relevant to the 

following MA and MF in SDF Monitoring Plan, Rev. 1: 

• MA 5 (Waste Form Chemical Degradation): 

o MF 5.01 (Radionuclide Release from Field-Emplaced Saltstone) 

2.5.2 Observation Results: 

The key points of the technical discussion were: 

• The DOE was surprised by the small difference between rhenium release under oxic and 

anoxic conditions in one experiment. 

• The DOE was surprised by an apparently abrupt change in Tc oxidation state in 

simulated saltstone samples aged between 350 and 450 days (indicative of Tc(VII) 

diminishing). 

• The oxidation state of Tc in various sulfide and oxide species that may be present in 

saltstone. 

2.5.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor DOE research plans and results. The NRC staff will 

continue to monitor the DOE SDF activities. The following Follow-Up Action Item resulted from 

the technical discussion: 
- 8 - 

• The DOE will provide the NRC with a listing of existing papers relative to technetium 

reduction/solubility. 

2.6 Technical Discussion – DOE Collection of Core Samples: 

2.6.1 Observation Scope: 

The technical discussion supported the NRC monitoring of the DOE disposal actions to assess 

compliance with 10 CFR 61.41, 10 CFR 61.42, and 10 CFR 61.43. The technical discussion 

was most relevant to the following MAs and MFs in SDF Monitoring Plan, Rev. 1: 

• MA 3 (Waste Form Hydraulic Performance): 

o MF 3.01 (Hydraulic Conductivity of Field-Emplaced Saltstone) 

o MF 3.03 (Applicability of Laboratory Data to Field-Emplaced Saltstone) 

• MA 5 (Waste Form Chemical Degradation): 

o MF 5.01 (Radionuclide Release from Field-Emplaced Saltstone) 

• MA 11 (Radiation Protection Program): 

o MF 11.01 (Dose to Individuals During Operations) 

2.6.2 Observation Results: 

The key points of the technical discussion were: 

• The DOE experience and process used to collect the core samples. 

• The worker dose for preparation was 822 person-mrem and the worker dose was 

between 587 person-mrem and 716 person-mrem for sampling from each of the three 

ports which resulted in a total job dose of 2,714 mrem. 

• The eight tests of physical and chemical properties that DOE will perform on the core 

samples. 

• The NRC commented that varying the solid-to-liquid ratio planned for the sorption 

coefficient tests would provide useful information about whether the results would be 

interpreted as sorption or solubility limited. 

• The NRC recognized both the technical difficulty of the DOE obtaining the core samples 

and the worker dose involved. 

• The NRC emphasized the importance of maintaining the core samples and conducting 

appropriate tests now to take advantage of the extensive work that was done to obtain 

the core samples. 

 
- 9 - 

2.6.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor DOE research plans and results. The NRC staff will 

continue to monitor the DOE SDF activities. The following Follow-Up Action Item resulted from 

the technical discussion: 

• The DOE will provide the NRC with the following documents: 

o “SRR-CWDA-2015-00002, FY 2015 Saltstone Core Drilling Mock-up Summary;” 

o “SRR-CWDA-2015-00066, Summary of Saltstone Disposal Unit Cell 2A Core 

Drill Activities;” 

o “SRR-CWDA-2015-00087, Saltstone Disposal Facility SDU Cell 2A Core Drill 

Summary;” and 

o “SRNL-L3100-2015-00108, SDU 2A Core Sample Test Designation.” 

2.7 Technical Discussion – GoldSim Modeling: 

2.7.1 Observation Scope: 

The technical discussion supported the NRC monitoring of the DOE disposal actions to assess 

compliance with 10 CFR 61.41 and 10 CFR 61.43. The technical discussion was most relevant 

to the following MA and MF in SDF Monitoring Plan, Rev. 1: 

• MA 10 (Performance Assessment Model Revisions) 

o MF 10.01 (Implementation of Conceptual Models) 

2.7.2 Observation Results: 

The key points of the technical discussion were: 

• The DOE answered the NRC questions about file structure and dynamic link libraries 

related to getting the GoldSim model to run. 

• The DOE answered specific NRC questions about modeled fluid flows and contaminant 

fluxes in various parts of the model. 

2.7.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor the DOE SDF activities. The following Follow-Up Action 

Items resulted from the technical discussion: 

• The DOE will provide to the NRC documentation on how to set up computer for a 

GoldSim run. 

• The DOE will provide to the NRC documentation on how locations along the 100-meter 

boundary were determined for the GoldSim model. 
- 10 - 

2.8 Technical Discussion – NRC RAIs on DOE FY 2014 Special Analysis Document:

2.8.1 Observation Scope: 

The discussion supports the NRC monitoring of the DOE disposal actions to assess compliance 

with 10 CFR 61.41, 10 CFR 61.42, 10 CFR 61.43, and 10 CFR 61.44. The technical discussion 

was relevant to most of the MAs and most of the MFs in SDF Monitoring Plan, Rev. 1. 

2.8.2 Observation Results: 

The key points of the technical discussion were: 

• Given the short time since the DOE received the RAIs [ADAMS Accession 

No. ML15161A541], the NRC appreciated the thorough preparation by the DOE. 

• The NRC mentioned that the DOE still needed to address: (1) mechanical degradation 

beginning at the time of closure; (2) gas phase transport of oxygen into unsaturated 

fractures; and (3) uncertainty in the reducing capacity of saltstone and its ability to 

reduce Tc(VII) to Tc(IV). 

• The NRC provided major clarifications (i.e., RAIs: PAM-4, DSP-2, SP-1, SP-3, SP-4, 

SP-5, and SP-10) and minor clarifications to the RAIs that the DOE was interested in. 

2.8.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor the DOE SDF activities. There were no Follow-Up Action 

Items that resulted from the technical discussion: 

3.0 OVERALL CONCLUSIONS, STATUS OF MONITORING FACTORS, OPEN ISSUES, 

OPEN FOLLOW-UP ACTION ITEMS; AND ISSUANCE OF NRC TECHNICAL REVIEW 

REPORTS: 

3.1 Overall Conclusions: 

The information gathered during SDF Observation 2015-02 will be used for multiple NRC 

Technical Review Reports via memoranda, review of the DOE SDF FY14 Special Analysis 

document, and future OOVs, based on the topics discussed. There is no change to the NRC 

staff overall conclusions from the 2012 TER regarding compliance of DOE disposal actions with 

the 10 CFR Part 61 performance objectives. The main key message from the OOV was that the 

NRC emphasized the importance of maintaining the core samples and conducting appropriate 

tests now to take advantage of the extensive work that was done to obtain the core samples.

 
- 11 - 

3.2 Status of Monitoring Factors in SDF Monitoring Plan, Rev. 1: 

SDF Observation 2015-02 is the third OOV under SDF Monitoring Plan, Rev. 1. The NRC staff 

did not close any monitoring factors during the OOV. Therefore, all 73 monitoring factors in 

SDF Monitoring Plan, Rev. 1 remain open. 

3.3 Status of Open Issues for SDF Monitoring: 

All previous NRC concerns were rolled into the Monitoring Factors in the 2013 SDF Monitoring 

Plan, Rev. 1. There were no SDF Open Issues at the beginning of SDF Observation 2015-02. 

The NRC staff did not open any new Open Issues during the OOV. Therefore, there are 

currently no SDF Open Issues. 

3.4 Status of Open Follow-up Action Items from Previous SDF OOV Reports: 

There were 16 previous NRC SDF OOVs. All but two of the Follow-Up Action Items from those 

OOVs were closed prior to SDF Observation 2015-02 and those two Follow-Up Action Items 

were closed during SDF Observation 2015-02. 

3.5 Status of Open Follow-up Action Items from Clarifying Teleconference Calls: 

All Follow-Up Action Items from previous clarification teleconference calls were closed prior to 

SDF Observation 2015-02. 

3.6 Summary of Follow-Up Action Items Opened During this Onsite Observation Visit: 

The table below contains the 11 Follow-Up Action Items that were opened during SDF 

Observation 2015-02, including a unique NRC identifier for each Follow-Up Action Item: 

Unique Identifier Follow-Up Action Item 

SDF-CY15-02-001 The DOE will provide the NRC with information on SDS 3A, SDS 3B, 

SDS 5A, and SDS 5B fill height restrictions related to resolution of 

mercury Potential Inadequacy in the Safety Analysis. 

SDF-CY15-02-002 The DOE will provide the NRC with the document “SRR-CWDA-2014-

00124, Determination of SDF Inventories through 9/30/2014.” 

SDF-CY15-02-003 The DOE will provide the NRC with the inventory in SDS 5B through 

09/30/2015. 

SDF-CY15-02-004 The DOE will provide the NRC with photographs from the tour of the 

SDF disposal structures on 07/07/2015. 

SDF-CY15-02-005 The DOE will provide the NRC with the 2015 mid-year groundwater 

monitoring report, when available. 

SDF-CY15-02-006 The DOE will provide the NRC information available on production 

well (SDS 6) depth and potential impact on surface settlement. 
- 12 - 

SDF-CY15-02-007 The DOE will provide to the NRC information about water tanks that 

the SDS 6 construction company built in Syracuse, New York and 

used as a model for SDS 6. 

SDF-CY15-02-008 The DOE will provide the NRC with a listing of existing papers relative 

to technetium reduction/solubility. 

SDF-CY15-02-009 The DOE will provide the NRC with the following documents: 

• “SRR-CWDA-2015-00002, FY 2015 Saltstone Core Drilling 

Mock-up Summary;” 

• “SRR-CWDA-2015-00066, Summary of Saltstone Disposal 

Unit Cell 2A Core Drill Activities;” 

• “SRR-CWDA-2015-00087, Saltstone Disposal Facility SDU 

Cell 2A Core Drill Summary;” and 

• “SRNL-L3100-2015-00108, SDU 2A Core Sample Test 

Designation.” 

SDF-CY15-02-010 • The DOE will provide to the NRC documentation on how to set 

up computer for a GoldSim run. 

SDF-CY15-02-011 • The DOE will provide to the NRC documentation on how 

locations along the 100-meter boundary were determined for 

the GoldSim model. 

3.7 Issuance of NRC Technical Review Reports: 

Between the previous OOV and SDF Observation 2015-02, the NRC issued one SDF Technical 

Review Report via memorandum: 

• Technical Review: “Oxidation of Reducing Cementitious Waste Forms” [ADAMS 

Accession No. ML15098A031] dated June 14, 2015, which had no Follow-Up Action 

Items. 

4.0 PARTICIPANTS:

U. S. NRC SCDHEC U.S. DOE SRR

George Alexander Tom Knight Dan Ferguson Tim Coffield 

Hans Arlt Justin Koon Sherri Ross Steve Hommel 

Terrence Brimfield Alan Risa Linda Suttora Jerry Mangold 

Harry Felsher Roger Schweitzer Armanda Watson Larry Romanowski 

Karen Pinkston Jason Shirley Kent Rosenberger 

A. Christianne Ridge Scott Simons Steve Simner 

 Andrea Skinner Owen Stevens 

 Steve Thomas 

 David Watkins 
- 13 - 

5.0 REFERENCES:

10 CFR Part 61, Federal Register, “Licensing Requirements for Land Disposal of Radioactive 

Waste,” Code of Federal Regulations, Office of the Federal Register, January 2001. 

U.S. Congress, Public Law 108-375, “Ronald W. Reagan National Defense Authorization Act for 

Fiscal Year 2005, Section 3116, Defense Site Acceleration Completion,” October 2004. 

U.S. Department of Energy (DOE), DOE Manual 435.1-1, Change 1, “Radioactive Waste 

Management Manual,” June 2001. ML15022A083. 

_____ DOE Order 435.1, Change 1, “Radioactive Waste Management,” August 2001. 

ML15022A088. 

_____ DOE-WD-2005-001, Rev. 0, “DOE Draft Basis for Section 3116 Determination Salt 

Waste Disposal at the Savannah River Site,” February 2005. ML051020072. 

_____ DOE-WD-2005-001, Rev. 1, “DOE Basis for Section 3116 Determination Salt Waste 

Disposal at the Savannah River Site,” January 2006. ML102850319. 

_____ “Response to NRC Letter of Concern (Type-IV) Regarding DOE Disposal Activities at the 

Savannah River Site Saltstone Disposal Facility,” July 2012. ML12198A258. 

_____ “Additional Response to NRC Technical Evaluation Report for Revised Performance 

Assessment for the Saltstone Disposal Facility at the Savannah River Site, South Carolina and 

the Letter of Concern,” July 2012. ML12215A081. 

_____ SRR-CWDA-2009-00017, Rev. 0, “Performance Assessment for the Saltstone Disposal 

Facility at the Savannah River Site,” October 2009. ML101590008. 

_____ “SRR-CWDA-2013-00073, Rev. 2, Updates to the Saltstone Disposal Facility Stochastic 

Fate and Transport Model,” August 2014. ML15225A473. 

_____ SRR-CWDA-2015-00086, Rev. 1, “Presentation for Savannah River Site Salt Waste 

Disposal NRC Onsite Observation Visit,” July 2015. ML15223B096. 

_____ SRR-CWDA-2014-00099, Rev. 1, “Comment Response Matrix for NRC Request for 

Additional Information on the Fiscal Year 2013 Special Analysis for the Saltstone Disposal 

Facility at the Savannah River Site,” January 2015. ML15020A672. 

_____ SRR-SPT-2012-00049, Rev. 1, “Saltstone Sampling and Analyses Plan,” May 2013. 

ML14196A215. 

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

Determination for Salt Waste Disposal,” December 2005. ML053010225. 
- 14 - 

_____ “NRC Plan for Monitoring Disposal Actions Taken by DOE at the Savannah River Site 

Saltstone Disposal Facility in Accordance with the National Defense Authorization Act for Fiscal 

Year 2005,” Rev. 0, May 2007. ML070730363. 

_____ “NRC Staff Guidance for Activities Related to DOE Waste Determinations – Draft Final 

Report for Interim Use,” August 2007. ML072360184. 

_____ “Technical Evaluation Report for the Revised Performance Assessment for the Saltstone 

Disposal Facility at the Savannah River Site, South Carolina,” April 2012. ML121020140. 

_____ “Letter of Concern (Type-IV) Regarding DOE Disposal Activities at the Savannah River 

Site Saltstone Disposal Facility,” April 2012. ML120650576. 

_____ “Letter to Terrel Spears of DOE, Acknowledging Receipt of July 12, 2012, Letter 

Regarding NRC's Letter of Concern (Type-IV) Regarding Disposal at the Savannah River Site,” 

August 29, 2012. ML12213A447. 

_____ “NRC Plan for Monitoring Disposal Actions Taken by DOE at the Savannah River Site 

Saltstone Disposal Facility in Accordance with the National Defense Authorization Act for Fiscal 

Year 2005,” Rev. 1, September 2013. ML13100A113. 

_____ “NRC Comments and Requests for Additional Information on the "DOE Fiscal Year 2013 

Special Analysis for the Saltstone Disposal Facility at the Savannah River Site,” SRR-CWDA2013-00062, Rev. 2,” June 2014. ML14148A153. 

_____ “NRC February 4 – 5, 2015, Onsite Observation Visit Report for the Savannah River Site 

Saltstone Disposal Facility,” May 2015. ML15041A562. 

_____ “NRC Onsite Observation Guidance for July 7 – 8, 2015, Monitoring Visit to the 

Savannah River Site, Saltstone Disposal Facility,” June 8, 2015. ML15148A388. 

_____ “NRC Technical Review: “Oxidation of Reducing Cementitious Waste Forms,” 

June 2015. ML15098A031. 

_____ “NRC Request for Additional Information Questions on the "DOE Fiscal Year 2014 

Special Analysis for the Saltstone Disposal Facility at the Savannah River Site," SRR-CWDA2014-00006, Rev. 2,” June 2015. ML15161A541. 
Attachment 

DETAILED TECHNICAL INFORMATION FROM 

U.S. NUCLEAR REGULATORY COMMISSION 

JULY 7 – 8, 2015, ONSITE OBSERVATION VISIT TO 

THE SAVANNAH RIVER SITE SALTSTONE DISPOAL FACILITY

Technical Discussion – DOE SDF Operating Status and Disposal Structure Status

The DOE provided updates on processing of Salt Batch 7 and Salt Batch 8. Salt Batch 8 will 

have a higher technetium (Tc) concentration than Salt Batch 7. Tank 50 contained part of Salt 

Batch 7 with a small amount of Salt Batch 8, which did not appreciably affect the Tc 

concentrations. There will be a delay before processing the remainder of Salt Batch 8. 

The DOE indicated that there was a Toxicity Characteristic Leaching Procedure (TCLP) test 

result that had a higher mercury (Hg) concentration than expected. The DOE was in the 

process of meeting with the State of South Carolina (i.e., SRS regulator of Savannah River Site 

(SRS)) to resolve that Hg issue. The DOE speculated that the increase in the Hg concentration 

was attributable to a change in the origin of the waste because the waste with the unexpectedly 

high Hg concentration originated from the H-Tank Farm. Tanks in the H-Tank Farm have 

approximately 40 times higher Hg concentrations than tanks in the F-Tank Farm. 

The DOE indicated that there had been a reduction in the fill height limit for the 150-foot 

disposal structures from 21.5 feet to 19.0 feet because of concerns about dimethyl mercury. 

The change in fill height was expected to be a temporary condition pending further analysis. As 

a Follow-Up Action Item, the DOE will provide the NRC with information on Saltstone Disposal 

Structure (SDS) 3A, SDS 3B, SDS 5A, and SDS 5B fill height restrictions related to resolution of 

“Mercury Potential Inadequacy in the Safety Analysis.” An analysis had already been done that 

supported the safety of SDS 2A and SDS 2B, both of which were already filled to 21.25 feet. 

In response to an NRC staff question, the DOE indicated that, as of June 30, 2015, there were 

approximately 64 curies (Ci) of Tc in SDS 5B. When SDS 5B is full, it will contain about 100 Ci 

of Tc. As a Follow-Up Action Item, the DOE will provide the NRC with the document “SRRCWDA-2014-00124, Determination of SDF Inventories through 9/30/2014.” As a Follow-Up 

Action Item, the DOE will provide the NRC with the inventory in SDS 5B through 09/30/2015. At 

the OOV, the SDS 5B inventory Follow-Up Action Item was going to be through 06/30/2015, but 

after the OOV, the NRC and the DOE agreed to change it to 09/30/2015. 

Technical Discussion – Routine Documentation and Follow-Up Action Items from Previous NRC

Monitoring Activities

The DOE provided the status summary of routine documents, including documents about 

inventory, provided by the DOE to the NRC (see more information about routine documents in 

the DOE presentation for SDF Observation 2015-02 [ADAMS Accession No. ML15223B096]). 

The NRC and the DOE agreed that all but two of the previous Follow-Up Action Items were 

closed prior to the OOV (see more information about closing Follow-Up Action Items in the DOE 

presentation for the OOV). The two open Follow-Up Action Items were discussed by the DOE 
- 2 - 

during the OOV and the NRC determined that those two Follow-Up Action Items, including items 

about groundwater, were closed. 

• SDF-CY15-01-001: (the DOE provided the photos in the presentation for the OOV)

o DOE to provide NRC with additional photos of construction of SDS 6 including: 

 tension wires; and 

 wall to roof connections 

• SDF-CY15-01-008: (the DOE provided the information during the OOV)

o The DOE to provide the NRC staff with additional groundwater data relative to: 

 historical data on Z-Area wells 

• water thickness of upper zone of the Upper Three Runs Aquifer 

over time. 

 additional well data related to changes in position of the water line 

between the lower and upper zones of the Upper Three Runs Aquifer 

over time 

Tour – SDS 2A, SDS 2B, SDS 3A, SDS 3B, SDS 4, SDS 5A, SDS 5B, and 

Construction of SDS 6

The tour consisted of the DOE driving the NRC around SDS 2A, SDS 2B, SDS 3A, SDS 3B, 

SDS 5A and SDS 5B; the DOE leading the NRC on a walking tour around SDS 4; and the DOE 

and the NRC observing application of pre-stressing wires in the construction of SDS 6 from an 

observation platform overlooking SDS 6. As a Follow-Up Action Item, the DOE will provide the 

NRC with photographs from the tour of the SDF disposal structures on 07/07/2015. 

During the walking tour of SDS 4, the DOE described features of the drain system and historical 

releases from SDS 4. During operations in the 1990s, Cell G of SDS 4 leaked. Previously, the 

DOE determined that contaminants from that leak reached the unsaturated zone and saturated 

zone. The DOE again indicated that the release was responsible for the elevated nitrate and Tc 

concentrations measured in Well ZBG-2. 

In 2011, precipitation accumulating on top of SDS 4, may have flowed through cracks in SDS 4, 

and contaminated the ground surface. The DOE remediated the soil around SDS 4 and 

determined that the remaining contaminants were immobile. The DOE constructed a drain 

system just under the surface that encircled SDS 4. The drain system was intended to capture 

any future storm water runoff from SDS 4 and direct it into a sedimentation basin. Also, the 

DOE built “huts” around the base of SDS 4 to cover the contaminated areas to prevent 

recharge. The DOE indicated that the contaminants from that leak did not reach the saturated 

zone and were not present under SDS 4. 

In early 2013, contaminated storm water from the SDS 4 area traveled through the drain system 

and flowed into the outfall culvert area and then to the sedimentation basin. The outfall culvert 

area is approximately 260 meters (850 feet) long. The DOE probe surveys identified areas with 

radiation above background levels. 
- 3 - 

In response to an NRC staff question, the DOE indicated that a comparison between observed 

concentrations in Well ZBG-2 and predictions of the area’s groundwater model were performed 

and that the model predictions matched the measured values in Well ZBG-2 reasonably well. 

Modeling was challenging because of uncertainty about the initial inventory that was released. 

Also, any standing water during the storm event would have driven the plume into the soil faster 

than predicted by a model that only considered average infiltration rates. In addition, the 

modeling effort was complicated by the potential for perched water on top of the Tan Clay 

Confining Zone (TCCZ). The NRC staff agreed with those DOE statements about the 

challenging aspects of modeling. The NRC indicated that the SDF Performance Assessment 

(PA) model predicted contamination moving into the Lower Zone of the Upper Three Runs 

(UTR) Aquifer (UTRA-LZ) (i.e., below the TCCZ); whereas Well ZBG-2 has shown 

contamination in the Upper Zone of the UTR aquifer (UTRA-UZ) (i.e., above the TCCZ). 

Tour and Technical Discussion – Groundwater Monitoring

The tour consisted of visiting locations of both existing and planned DOE groundwater 

monitoring wells as well as sites where the DOE plans to use Direct Push Technology (DPT) 

and Cone Penetrometer Tests (CPT). The NRC and DOE staff discussed the closure of Well 

ZBG-2 and the development of nearby Well ZBG-2C and Well ZBG-2D. As indicated in the 

NRC report for SDF Observation 2015-01 (ADAMS Accession No. ML15041A562), the DOE 

decided to close ZBG-2 because it penetrates the top of the TCCZ and the DOE determined 

that closing the well would reduce the potential for cross-contamination of the aquifers. Well 

ZBG-2 will be replaced by both Well ZBG-2C, which will be screened entirely below the TCCZ, 

and Well ZBG-2D, which will be screened entirely above the TCCZ. 

The DOE explained that the DOE 2015 mid-year groundwater monitoring report will be the last 

report to show data from Well ZBG-2, which previous reports showed had elevated 

concentrations of nitrate and Tc. The DOE indicated that the DOE 2015 mid-year groundwater 

monitoring report will show data from Well ZBG-2C; but, data from Well ZBG-2D will be first 

available in the final DOE 2015 annual groundwater monitoring report. As a Follow-Up Action 

Item, the DOE will provide the NRC with the 2015 mid-year groundwater monitoring report, 

when available. 

In addition, data from Cone Penetrometer Tests and Direct Push Technology will be available in 

the DOE final 2015 annual groundwater monitoring report. The NRC staff expects that the data 

will provide useful information about the Conceptual Site Model for potential groundwater flow 

within the UTRA-UZ for much of the Z-Area and for contaminant transport, within and between, 

the TCCZ, the UTRA-LZ, and the UTRA-UZ. 

During the technical discussion of groundwater data, the SRS South Carolina regulator, South 

Carolina Department of Health and Environmental Control (SCDHEC), staff raised a concern 

that contaminants will migrate from the unlined sedimentation basins north of SDS 4 into the 

groundwater. The NRC staff will continue to monitor contaminant concentrations in Well 

ZBG-16C which is downgradient of the sedimentation basins. Well ZBG-16D, which is also 

downgradient of the sedimentation basins, is typically dry. The NRC staff will follow up with 

DOE as part of our normal monitoring activities if NRC staff has any concerns. 
- 4 - 

The DOE, the NRC, and the SCDHEC staff discussed the three production wells being installed 

in the Z-Area in preparation for the hydrotest of SDS 6. The SCDHEC staff raised the concern 

that the production wells were spaced closely enough that they appeared likely to cause 

interference with each other (i.e., amount that could be pumped from all three wells 

simultaneously might not be three times the amount that could be pumped from one individual 

well). The NRC staff repeated previous concerns from the report for SDF Observation 2015-01 

about the need to better understand whether there was potential for subsidence from pumping 

water from the Congaree Aquifer. The DOE clarified that, in contrast to the discussion during 

SDF Observation 2015-01, the wells will be screened in the Crouch Branch Aquifer, which is 

below the Congaree Aquifer. The DOE indicated that there are other locations onsite that pump 

from the Crouch Branch Aquifer at a similar rate and those locations experience rapid recovery 

from drawdown, so drawdown was not expected to cause significant subsidence at those three 

new production wells being installed in Z-Area. The SCDHEC staff raised a concern that 

although the DOE may have other wells that pump from the Crouch Branch Aquifer, it did not 

seem the DOE had measured ground surface deflection during pumping and therefore the DOE 

did not have evidence to show that there was no subsidence caused by pumping. The 

SCDHEC staff asked if the DOE had a basis for assuming that any deflection would not cause 

disposal structure cracking due to differential setting. As a Follow-Up Action Item, the DOE will 

provide the NRC information available on production well (SDS 6) depth and potential impact on 

surface settlement. 

The DOE indicated that the construction company that is building SDS 6 anticipated 

approximately a 25 percent chance that SDS 6 would leak during the hydrotest. The company 

has a protocol in place for detecting and repairing leaks and any leaks would be repaired before 

the SDS 6 is put into service. In response to an NRC request, as a Follow-Up Action Item, the 

DOE will provide to the NRC information about water tanks that the SDS 6 construction 

company built in Syracuse, New York and used as a model for SDS 6. 

The DOE indicated that funds were designated to update the General Separations Area (GSA) 

groundwater modeling. The NRC staff will follow-up on that GSA groundwater model update 

because it is important to monitoring the DOE disposal actions at both the SDF and two tank 

farms (i.e., F-Tank Farm, H-Tank Farm). 

Technical Discussion – DOE Research Update

The DOE indicated that it had been using EPA test 1315 to study release of rhenium (Re) from 

spiked simulated saltstone samples at various curing times. In general, Tc releases were about 

an order of magnitude smaller than Re releases under the same conditions. The DOE was 

surprised that there was very little difference in the release seen with oxygen-saturated and 

anoxic leachates. 

The DOE summarized anomalous results related to neptunium (Np) releases from the fieldscale lysimeter study. One replicate showed an order of magnitude faster release of Np than 

the other; but, both releases were considered to be very low. 

The DOE indicated that there were difficulties with the development of the dynamic leaching 

procedure. Specifically, there were difficulties in getting a good seal between the sample and 
- 5 - 

the test apparatus when a thinner sample was used to reduce the time needed to get several 

pore volumes through the sample. The DOE returned to using 5 centimeter (2 inch) thick 

samples to eliminate bypass flow. The DOE plans to use influents spiked with Tc(VII) to 

determine if re-reduction occurs when the influent passes through the simulated saltstone 

sample. 

The DOE discussed ongoing work at Clemson University to use X-ray Absorption Spectrometry 

(XAS) to study the oxidation state of Tc, iron, and sulfur (S) after different sample curing 

durations. The researchers saw evidence of TC2S7 and Tc oxides. The NRC commented that 

one of the lines of reasoning supporting experimentally observed Tc solubility values used in the 

DOE FY 2014 Special Analysis Document was the theoretical agreement between the observed 

results and specific Tc oxide species. The DOE and the NRC discussed the oxidation state of 

Tc in various sulfide and oxide species. As a Follow-Up Action Item, the DOE will provide the 

NRC with a listing of existing papers relative to technetium reduction/solubility. 

The DOE described results showing XAS features indicative of Tc(VII) diminishing between 

350 days and 450 days after the samples were poured. The DOE indicated that more work was 

needed to better understand that result because the expectation was a more gradual decline; 

however, no additional work has been funded. In response to an NRC staff question, the DOE 

indicated that the report covering FY15 activities was expected to be issued at the end of FY15. 

Technical Discussion – DOE Collection of Core Samples

In the NRC 2007 SDF Monitoring Plan [ADAMS Accession No. ML070730363], the NRC 

identified scaling the properties of laboratory samples to field-emplaced saltstone as important 

for NRC monitoring at the SDF. That issue was carried forward as MF 3.03 and MF 5.01 in the 

NRC 2012 SDF Monitoring Plan [ADAMS Accession No. ML13100A076]. The DOE developed 

the Saltstone Sampling and Analyses Plan (SRR-SPT-2012-00049, Rev. 1) [ADAMS Accession 

No. ML14196A215] as the plan to study how well laboratory-prepared samples represent the 

properties of field-emplaced samples. That plan included the collection of core samples. 

The DOE discussed how they collected core samples from SDS 2A. Samples were collected 

from two locations in each of three camera ports (i.e., total of six samples). Despite successful 

drilling experiences with the mock-up, there were technical difficulties with the first and second 

field-scale drilling attempts. As a Follow-Up Action Item, the DOE will provide the NRC with the 

following documents: 

• “SRR-CWDA-2015-00002, FY 2015 Saltstone Core Drilling Mock-up Summary;” 

• “SRR-CWDA-2015-00066, Summary of Saltstone Disposal Unit Cell 2A Core Drill 

Activities;” 

• “SRR-CWDA-2015-00087, Saltstone Disposal Facility SDU Cell 2A Core Drill Summary;” 

and 

• “SRNL-L3100-2015-00108, SDU 2A Core Sample Test Designation.” 

To compare the cores from the field-emplaced samples to specific batches of saltstone, the 

samples were collected from SDS 2A at particular depths. Those depths corresponded to 
- 6 - 

saltstone poured into SDS 2A on the same day that samples were taken directly from the 

Saltstone Production Facility and cured in the laboratory (i.e., August 2013). The field-scale 

material at the depth corresponding to the August 2013 pour of interest was harder than the 

saltstone poured in either December 2013 or May 2014. Additional curing time was one 

hypothesis that had been discussed; but, it was unclear whether the difference in curing time 

between August and December 2013 could explain the difference in the saltstone hardness. 

The worker doses were reported as: 822 person-mrem for drilling preparation, 716 personmrem for sampling from Port A, 587 person-mrem for sampling from Port B, and 589 personmrem for sampling from Port C. This resulted in a total job dose of 2,714 mrem. 

The DOE plans to conduct the following tests on the core samples collected: 

1. Saturated Hydraulic Conductivity 

2. Density, Porosity, and Moisture Content 

3. Total Activity for Tc-99, strontium (Sr)-90, selenium (Se)-79, iodine (I)-129, 

Radium (Ra)-226 

4. Distribution Coefficient (Kd) for (Tc, Sr, Se, I, Ra) 

5. Ratio of Tc(VII)/Tc(Total) 

6. pH/Eh 

7. TCLP on reduced samples 

8. TCLP on oxidized samples 

The DOE commented that, although it was preferable to conduct those tests as soon as 

possible to minimize the costs associated with storing the core samples in an anoxic 

environment, the testing would be delayed until FY16 due to funding availability. 

In response to an NRC staff question, the DOE clarified that the measurement of Tc(VII) in 

Test #5 would actually be a measurement of leachable Tc, which may not be identical to the 

Tc(VII) in the sample. The DOE explained that the TCLP Test #7 and Test #8 were planned 

because SCDHEC was especially interested in Hg in the samples. 

The NRC commented that all of the tests were focused on initial properties. The NRC staff 

asked if any testing was anticipated that could provide support for the predicted performance of 

samples over time. The DOE suggested that a dynamic leaching test could provide information 

about saltstone oxidation over time and the NRC agreed. However, the DOE clarified that a 

dynamic leaching test was not within the current budget. The DOE commented that dynamic 

leaching tests, if done, would be done with laboratory samples and not with field samples 

because the laboratory samples were easier to work with because they are not as radioactive. 

The DOE reiterated that the two goals of the project were to understand: (1) the initial 

properties of field-emplaced saltstone; and (2) how well the laboratory samples represent the 

properties of the field-emplaced saltstone. The DOE commented the field samples included 

interfaces that had been exposed to air between lifts being poured. However, the DOE 

commented that it would be difficult to study the oxidation near those lift boundaries because 

core samples typically broke near lift boundaries and any breaks would be exposed to coring 

water, which would affect sample oxidation. 
- 7 - 

The NRC commented that varying the solid to liquid ratio planned for the Kd Test #4 tests would 

provide useful information about whether the results should be interpreted as sorption or 

solubility limited. 

The NRC recognized both the technical difficulty of the DOE obtaining the core samples and the 

worker dose involved. The NRC emphasized the importance of maintaining the core samples 

and conducting appropriate tests now to take advantage of the extensive work that was done to 

obtain the core samples. 

Technical Discussion – GoldSim Modeling

The NRC staff asked the DOE specific questions related to the dynamic link libraries (DLL) files 

to allow the GoldSim SDF model to run. The DOE described the necessary DLL file locations. 

As a Follow-Up Action Item, the DOE will provide to the NRC documentation on how to set up 

computer for a GoldSim run. The DOE explained that the “readporflow” DLL is used to tell 

GoldSim which PORFLOW flow field data to use, that the “TSPROC” DLL is used for time series 

processing, and that the “Transition time” DLL is used for the GoldSim Tc model to determine 

when chemical transitions occur resulting in Tc releases. 

In response to NRC staff questions, the DOE explained several modeling simplifications, 

including the use of mixing cells to model flow in the sheet drain and High Density Polyethylene. 

The DOE explained that in the document, “Updates to the Saltstone Disposal Facility Stochastic 

Fate and Transport Model, SRR-CWDA-2013-00073, Rev. 2 [ADAMS Accesssion 

No. ML15225A473] the “Fill Container” in Figure 4.1-22 was a modeling simplification that 

served as a reservoir for back-diffusion. The DOE explained that one reason there was a 

difference between the PORFLOW results and GoldSim results was because of differences in 

the modeling of lateral diffusion. In response to NRC staff questions, the DOE staff explained 

the purpose of several individual modeling containers, including where advective and diffusive 

releases were modeled. 

In response to an NRC question, DOE staff explained that locations for the 100-meter 

concentrations represented the point in the sector with the highest concentrations, which might 

not be the center of either the sector or of an individual plume because of plume overlap. As a 

Follow-Up Action Item, the DOE will provide to the NRC documentation on how locations along 

the 100-meter boundary were determined for the GoldSim model. 

Technical Discussion – NRC RAIs on DOE FY 2014 Special Analysis Document

The NRC provided an overview with the main themes of the NRC RAI Questions (RAIs) on the 

DOE FY 2014 SDF Special Analysis Document [ADAMS Accession No. ML15161A541]. 

Throughout the technical discussion, the DOE requested clarification on specific RAIs and 

provided suggestions for addressing various RAIs. The NRC discussed with the DOE whether 

the DOE proposed approach appeared to address that RAI. However, the NRC indicated that 

the NRC discussion points were preliminary and that the NRC will review the entirety of the 

future DOE written responses to the NRC RAIs for the new NRC TER. Given the short time 

since the DOE received the RAIs, the NRC appreciated the thorough preparation by the DOE. 
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Many minor clarifications were provided by the NRC during the technical discussion; but, only 

major clarifications are described below: 

The NRC mentioned topics of RAIs that were included in the NRC RAI Comments on the DOE 

FY 2013 SDF Special Analysis Document [ADAMS Accession No. ML14148A153]. Those 

topics included the following issues: (1) mechanical degradation beginning at the time of 

closure; (2) gas phase transport of oxygen into unsaturated fractures; and (3) uncertainty in the 

reducing capacity of saltstone and its ability to reduce Tc(VII) to Tc(IV). The NRC 

acknowledged that the DOE Response to the NRC RAI Comments on the DOE FY 2013 SDF 

Special Analysis Document [ADAMS Accession No. ML15020A672] indicated several topics 

where research that DOE was planned to address those issues. However, until the DOE 

research results were available, those topics were repeated in the RAIs. 

The NRC provided general comments about NRC RAI Question SP-10, which was about Tc 

release from saltstone. The RAI Question asks for information that could be supplied by the 

combination of the DOE sensitivity analysis cases that addressed: (1) less than expected rereduction of Tc in reduced areas of saltstone; and (2) poor correlation of saltstone oxidation and 

Tc release. NRC staff indicated that a combination of those analyses does not represent 

arbitrary “worst case” conditions. The cases were physically related because they both 

represented uncertainty in the conceptual model that Tc release will be a simple function of the 

reducing capacity in a local area in saltstone. Previously, the NRC had questioned the accuracy 

of that DOE conceptual model. The DOE responded by indicating that the planned research 

related to Tc release will be put into a revised PA model. Specifically, the DOE discussed 

planned research to perform depth-discrete sampling to evaluate the mobilization of Tc in 

different locations in a sample. 

Regarding the NRC RAI Question PAM-4, which was about conceptual model uncertainty 

related to climate change, the DOE indicated that DOE Order 435.1 requires conclusions of 

modeling results to 1,000 years post-closure, partially because uncertainties at longer times 

were difficult to predict. The NRC clarified that the RAI was not about predicting the effects of 

climate change; instead, the RAI was about the need for the DOE to address uncertainty in the 

PA model caused by possible future changes in disposal site events and processes due to 

climate change. The DOE expressed concern that it was difficult to communicate to the public 

that cases designed to bound uncertainty in future conditions were not the expected case. The 

NRC suggested that the DOE review the RAI in the context of MF 10.02 in the 2013 SDF 

Monitoring Plan. 

The DOE and the NRC discussed several RAIs related to the projected rate of hydraulic 

degradation of saltstone. Regarding NRC RAI Question SP-1, which was about decalcification, 

the DOE indicated that shortening the predicted degradation time due to decalcification would 

not have a significant effect on the model output. The NRC indicated that the DOE view was 

the previous NRC staff understanding; but, that view does not seem consistent with the results 

of the DOE sensitivity analyses using degradation multipliers. In a similar discussion related to 

the rate of degradation (RAI Question SP-3), the DOE indicated that the assumption that 

degradation occurs at a linear rate was conservative. The NRC indicated that more support 

was needed for that conclusion because the peak dose was likely to be related to the rate of 

change of the hydraulic properties and other degradation curves that involved a time period with 
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faster degradation could result in a higher projected peak dose even if there is less degradation 

at earlier times. The NRC discussed the potential evolution of pathways for water in porous 

solids and discussed mechanisms that could cause relatively gradual or even imperceptible 

changes until a certain level of degradation was reached and at that point, hydraulic properties 

could change more rapidly. The DOE and the NRC discussed the idea that channeling through 

saltstone could be beneficial for performance if water was directed away from most of the 

inventory. Regarding two RAIs related to delays before degradation was modeled to begin (RAI 

Question SP-5 and RAI Question DSP-2), the DOE suggested that responses may refer to 

sensitivity case results where the hydraulic conductivity was increased at the time of closure. 

The NRC replied that appeared to be one way to address those RAIs. 

The DOE questioned the risk-significance of NRC Question SP-4, which was about modeling 

hydraulic degradation in localized areas instead of modeling degradation as proceeding 

uniformly throughout saltstone. The NRC explained the concern that degradation localized in 

areas that were in more contact with water appeared to have the potential to focus water flow 

through areas where Tc had a higher chance of being oxidized. The NRC clarified that the RAI 

Question could potentially be answered with an analytical argument instead of results from a 

numerical model run. 

The DOE questioned why, in several unidentified RAIs, the NRC asked for projected dose 

results instead of fluxes or fractional releases for times in excess of 20,000 years after closure. 

The NRC explained that, given the uncertainty in the timing of the projected peak doses, it was 

not clear to the NRC that the Tc peaks would occur more than 10,000 years after closure. The 

DOE indicated that results in terms of dose beyond 20,000 years would not be provided to the 

NRC. The NRC responded that fluxes to the unsaturated zone could be converted dose results. 

However, results presented in terms of the cumulative fractional release were more difficult to 

interpret because the slope of that line, rather than the cumulative fractional release value itself, 

was directly related to dose. After the OOV, the DOE informed the NRC that dose results for 

those runs in which the simulations had been carried out beyond 20,000 years would be 

provided.