May 27, 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 FEBRUARY 4 – 5, 2015, 

ONSITE OBSERVATION VISIT REPORT FOR THE SAVANNAH RIVER SITE 

SALTSTONE DISPOSAL FACILITY (DOCKET NO. PROJ0734) 

Dear Ms. Ridley: 

The enclosed onsite observation visit report describes the U.S. Nuclear Regulatory Commission 

(NRC) onsite observation visit on February 4–5, 2015, at the Savannah River Site (SRS) 

Saltstone Disposal Facility (SDF). That onsite observation visit 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. This is the sixteenth SDF onsite observation visit since the NRC began monitoring 

the DOE SDF disposal actions under NDAA Section 3116(b) in October 2007. 

The main activities conducted during the February 2015 SDF onsite observation visit were a 

tour and technical discussions. The tour included: (i) construction of Saltstone Disposal 

Structure (SDS) 6, (ii) Saltstone Production Facility, (iii) new monitoring wells in Z-Area; and 

(iv) outside of SDS 3A, SDS 3B, SDS 5A, and SDS 5B. The 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) ongoing and future NRC 

research activities by the Center for Nuclear Waste Regulatory Analyses (CNWRA); (iv) DOE 

sampling and analyses plan research status; (v) iodine sorption and Tc solubility; (vi) Tan Clay 

Confining Zone (TCCZ) structure and ZBG-2 well sample results; (vii) SDS 3A sump 

Unreviewed Waste Disposal Question Evaluation (UWDQE); (ix) PORFLOW modeling for the 

DOE SDF Fiscal Year (FY)14 Special Analysis document; and (x) GoldSim modeling for the 

DOE SDF FY14 Special Analysis document. 

Those activities were consistent with those described in the NRC Observation Guidance 

Memorandum for the SRS SDF Onsite Observation Visit (dated December 5, 2014,) 

[ML14321A534]. That Guidance Memorandum was developed using the SDF Monitoring Plan, 

Rev. 1 (dated September 2013) [ML13100A113]. The SDF Monitoring Plan contains the 

monitoring areas and monitoring factors, which describe how the NRC will monitor the DOE 
J. Ridley -2- 

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. 

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

performance objective) or change the NRC staff TER overall conclusions as a result of this 

onsite observation visit. There were no SDF Open Issues before the February 2015 onsite 

observation visit and there were none identified during the onsite observation visit. Thus, there 

are currently no SDF Open Issues. 

The NRC does expect to open and close Follow-Up Action Items during onsite observation visits 

and clarification teleconference calls. Most of those Follow-Up Action Items are specific shortterm actions to be performed by the NRC or the DOE. Usually, most of those Follow-Up Action 

Items are closed before the next onsite observation visit or clarification teleconference call. 

A main focus point of the NRC staff performing an onsite observation visit under NDAA 

monitoring at the SDF is because on April 30, 2012, the NRC issued both a Technical 

Evaluation Report (TER) [available via the NRC Agencywide Documents Access and 

Management System (ADAMS) at Accession Number ML121020140] and a Type-IV Letter of 

Concern [ML120650576] pertaining to waste disposal at the SRS SDF. The 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 Type-IV Letter of Concern formally communicated the 

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

Environmental Control. The DOE provided responses to the Type-IV Letter to the NRC in 

multiple submittals. Those submittals included an updated technetium-99 (Tc-99) inventory 

projection for the constructed SRS disposal structures similar in design to SDS 2A and 

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

projections described in the DOE submittal are listed in reference to SDS 2A, SDS 2B, SDS 3A, 

SDS 3B, SDS 5A, and SDS 5B. In August 2012, the NRC issued a letter of acknowledgement 

[ML12213A447] 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 TER analyses 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 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. Therefore, in accordance 

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

disposal actions at SRS. 
J. Ridley -3- 

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

report, please contact Mr. Terrence C. Brimfield of my staff at Terrence.Brimfield@nrc.gov or at 

(301) 415-6069. 

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, please contact Mr. Terrence C. Brimfield of my staff at Terrence.Brimfield@nrc.gov or at 

(301) 415-6069. 

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 HFelsher KPinkston 

MRoberts/Region I MFerdas/Region I 

ML15041A562 

OFFFIC DWMEP:PM DWMEP:PAB DWMEP:LA DWMEP:BC DWMEP:BC DWMEP:DD 

NAME TBrimfield ARidge TMoon CMcKenney GSuber APersinko 

DATE 4/14/15 4/14/15 

email 

4/21/15 

email 4/27/15 5/19/15 5/27/15 

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 

FEBRUARY 4 – 5, 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 sixteenth onsite 

observation visit, Observation 2015-01, to the Saltstone Disposal Facility (SDF) at the 

Savannah River Site (SRS) on February 4 – 5, 2015. This is the first SDF onsite observation 

visit in Calendar Year (CY) 2015. On every onsite observation visit 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). 

For SDF Observation 2015-01, the NRC focused on the monitoring areas and monitoring factors 

in the SDF Monitoring Plan, Rev. 1 (September 2013). This is the second SDF onsite 

observation visit under SDF Monitoring Plan, Rev. 1. All previous NRC concerns have been 

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

monitoring activities in coordination with the State, therefore South Carolina Department of 

Health and Environmental Control (SCDHEC) staff also participated in SDF Observation 2015-

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

received from the DOE during SDF Observation 2015-01. 

As described in the Observation Guidance Memorandum for SDF Observation 2015-01 

(December 2014), the NRC staff and the DOE (i.e., includes DOE contractors throughout this 

onsite observation visit report) had a tour and technical discussions. The tour included: 

(i) construction of Saltstone Disposal Structure (SDS) 6, (ii) Saltstone Production Facility, 

(iii) new monitoring wells in Z-Area; and (iv) outside of SDS 3A, SDS 3B, SDS 5A, and SDS 5B. 

The 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) ongoing and future NRC research activities by the Center for Nuclear Waste 

Regulatory Analyses (CNWRA); (iv) DOE sampling and analyses plan research status; 

(v) iodine sorption and Tc solubility; (vi) Tan Clay Confining Zone (TCCZ) structure and ZBG-2 

well sample results; (vii) SDS 3A sump Unreviewed Waste Disposal Question Evaluation 

(UWDQE); (ix) PORFLOW modeling for the DOE SDF Fiscal Year (FY)14 Special Analysis 

document; and (x) GoldSim modeling for the DOE SDF FY14 Special Analysis document. This 

onsite observation visit report provides a description of the NRC activities during SDF 

Observation 2015-01, including observations made by the NRC staff. 

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

performance objective) or change the NRC staff TER overall conclusions as a result of this 

onsite observation visit. There were no SDF Open Issues before the February 2015 onsite 

observation visit and there were none identified during that onsite observation visit. 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. 
- 2 - 

The NRC staff received the updated DOE presentation (SRR-CWDA-2015-00011, Rev. 1) that 

pertained to the activities observed during SDF Observation 2015-01. That DOE presentation is 

accessible via the NRC document repository, the Agencywide Documents Access and 

Management System (ADAMS), via Accession No. ML15070A359. 

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) 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, 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-WD-2005-001, Rev. 1). 

The DOE submitted a revised Performance Assessment to the NRC in 2009 (SRR-CWDA2009-00017). The NRC reviewed SRR-CWDA-2009-00017, including holding public meetings, 

sending requests for additional information, and reviewing the DOE responses. On April 30, 

2012, the NRC issued both the TER and a Type-IV Letter of Concern. 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. 

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

DOE responses included an updated technetium-99 (Tc-99) inventory projection for the 

constructed disposal structures similar in design to Saltstone Disposal Structure (SDS) 2A and 

information about the DOE Case K and K1 uncertainty and sensitivity analyses. In August 

2012, the NRC issued a letter of acknowledgement [ML12213A447] to 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 analyses 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 would cause an 

off-site peak dose exceeding the requirements of §61.41 (i.e., 0.25 mSv/yr (25 mrem/yr)). 

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

with the State site regulator – SCDHEC, performs three types of activities: (1) technical 

reviews, (2) onsite observation visits, and (3) data reviews. Those activities focus on both: 
- 3 - 

(1) key modeling assumptions identified in the NRC SDF Monitoring Plan, Rev. 1; and (2) the 

DOE disposal actions. Technical reviews generally focus on review of information generated to 

provide support for key assumptions that the DOE made in the SDF Performance Assessment 

or supplements, such as special analyses. Onsite observation visits generally are performed to 

either: (1) observe the collection of data and review the data to assess consistency with 

assumptions made in the SDF final Waste Determination; or (2) observe key disposal or closure 

activities related to technical review areas. Data reviews supplement 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 December 5, 2014, the NRC issued the Observation Guidance [ML14321A534] for the 

February 4 – 5, 2015, onsite observation visit, SDF Observation 2015-01. An Observation 

Guidance is a plan for what NRC expects to cover during an onsite observation visit, which may 

be changed based on what happens during the onsite observation visit. 

The SDF Observation 2015-01 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 onsite observation visit consisted of a tour and technical 

discussions. The tour included: (i) construction of SDS 6, (ii) Saltsone Production Facility, 

(iii) new monitoring wells in Z-Area; and (iv) outside of SDS 3A, SDS 3B, SDS 5A, and SDS 5B. 

The 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) ongoing and future NRC research activities by the Center for Nuclear Waste 

Regulatory Analyses (CNWRA); (iv) DOE sampling and analyses plan research status; 

(v) iodine sorption and Tc solubility; (vi) Tan Clay Confining Zone (TCCZ) structure and ZBG-2 

well sample results; (vii) SDS 3A sump Unreviewed Waste Disposal Question Evaluation 

(UWDQE); (ix) PORFLOW modeling for the DOE SDF FY14 Special Analysis document; and 

(x) GoldSim modeling for the DOE SDF FY14 Special Analysis document. 

2.1 Tour – Construction of SDS 6, Saltstone Production Facility, new monitoring wells in ZArea; and outside of SDS 3A, SDS 3B, SDS 5A, and SDS 5B: 

2.1.1 Observation Scope: 

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

10 CFR 61.41 and 10 CFR 61.42. This tour was most relevant to the following monitoring areas 

(MAs) and monitoring factors (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) 
- 4 - 

• MA 8 (Environmental Monitoring): 

o MF 8.02 (Groundwater Monitoring) 

2.1.2 Observation Results: 

The NRC staff and the DOE toured construction of SDS 6, including the floor and roof. The 

NRC staff observed that: (i) the floor of SDS 6 was in place, (ii) several roof panels had been 

placed; and (iii) pouring of concrete for wall panels and roof support columns was partially 

complete. The NRC staff observed construction details of SDS 6, such as: (i) forms for pouring 

of concrete for wall panels and columns, including placement of rebar; (ii) placement of bearing 

pad under wall panels; and (iii) placement of water stops between wall panels and between roof 

panels. The DOE showed the NRC staff pictures of SDS 6 construction on a laminated card. 

In response to the NRC staff questions, the DOE explained that the SDS 6 concrete remains 

under cure blankets until it attains 3,500 pounds per square inch (psi) (~24.13 megapascal) 

strength. The DOE indicated that was in accordance with industry standards and, in the 

weather conditions during SDF Observation 2015-01, that standard was typically met within 

three weeks. 

The DOE brought the NRC staff to the Saltstone Production Facility where the DOE provided an 

overview of the location and process. The Saltstone Production Facility was not operating. In 

vehicles, the DOE showed the NRC staff the locations of two new groundwater monitoring wells 

in the Z-Area and the outside of several disposal structures (i.e., SDS 3A, SDS 3B, SDS 5A, 

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 that tour: 

• The DOE to provide the NRC staff with additional photos of construction of SDS 6 

including: 

o photos contained in the laminated card utilized during tour; 

o aerial photos; 

o column rebar photos of the following: 

 column pedestal to floor 

 column to pedestal 

 column to roof 

o intersection of roof joints with waterstop; 

o wall bearing pads; 

o wall joints (e.g., waterstop, bearing pads); 
- 5 - 

o tension wires; and 

o wall to roof connections. 

2.2 Technical Discussion – DOE SDF operating status and disposal structure status:

2.2.1 Observation Scope: 

This 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. This 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) 

o MF 1.02 (Methods used to Assess Inventory) 

• MA 8 (Environmental Monitoring): 

o MF 8.01 (Leak Detection) 

o MF 8.02 (Groundwater Monitoring) 

• MA 11 (Radiation Protection Program): 

o MF 11.01 (Dose to Individuals During Operations) 

2.2.2 Observation Results: 

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

(SRR-CWDA-2015-00011) [ML15070A359]. Major points from that presentation were: 

Status of filling of disposal structures with saltstone: 

The DOE informed the NRC that: (1) SDS 2A and SDS 2B were filled to 21.25 feet 

(6.48 meters) with saltstone; (2) SDS 5B was beginning to be filled; and (3)SDS 3A, SDS 3B, 

and SDS 5A were ready to be filled. Also, in August 2014, the DOE switched the Saltstone 

Production Facility from a 10-hour workday to a 12-hour workday. 

Stabilization of SDS 4: 

During SDF Observation 2014-01 in May 2014, the DOE indicated that the six North cells had 

been coated and sealed. Since then, the DOE added a clean cap to five of the six South cells. 

The purpose of the clean cap was to reduce radiation levels so that the cells could be coated 

and sealed. The remaining one South cell is scheduled to have a clean cap added in the 

second quarter of CY15. One of the North cells that had been coated and sealed is scheduled 

to have more clean cap added to reduce radiation exposures on the roof. 
- 6 - 

Individual whole body doses of the DOE personnel: 

The DOE compared the top 10 individual whole body doses from CY14 with the top 10 

individual doses from CY13. The DOE indicated that the CY14 doses were slightly higher than 

the CY13 doses for the following two reasons: (1) Defense Waste Processing Facility doses 

were now included with the SDF doses; and (2) higher SDF doses were attributable to the SDS 

4 stabilization work. The DOE indicated that in CY14 there were no unexpected exposures and 

there were no exposures above either regulatory limits or SRS action levels. The NRC staff 

noted that all doses were less than 5.0 mSv (500 mrem). 

2.2.3 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 that technical discussion: 

• The DOE to provide the NRC staff with a table containing Tank 50 sample quarterly 

report historical information. 

2.3 Technical Discussion – Routine documentation and Follow-Up Action Items from 

previous NRC monitoring activities: 

2.3.1 Observation Scope: 

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

compliance with 10 CFR 61.41 and 10 CFR 61.42. This 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) 

2.3.2 Observation Results: 

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

closed prior to SDF Observation 2015-01 (see more information about documents closing 

Follow-Up Action Items in the DOE presentation [ML15070A359]). The one open Follow-Up 

Action Item was discussed and indicated as closed later in this onsite observation visit report. 

The NRC staff questioned the DOE about the timing of anticipated changes in Tc-99 

concentrations in salt waste sent and to be sent to the Saltstone Production Facility, as 

described in the DOE letter for the SDF FY14 Special Analysis document [ML14322A259]. The 

DOE explained that the Actinide Removal Process (ARP)/Modular Caustic Side Solvent 

Extraction Unit (MCU) was processing Salt Batch 7 (SRNL-STI-2013-00437) [ML14002A062] 

and that samples for Salt Batch 8 were being characterized. The DOE indicated that NRC staff 
- 7 - 

would be kept apprised of the Salt Batch 8 results and that the DOE would provide an estimate 

for the timing of an anticipated increase in the Tc concentration in salt waste to be sent to the 

Saltstone Production Facility. In response to an NRC staff question, the DOE indicated that the 

NRC staff would soon receive the 2014 Annual Inventory Report. 

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 that technical discussion: 

• The DOE to provide the NRC staff with the Salt Batch 8 qualification report, when 

available, and information on the timing of processing future batches, including 

anticipated increase in Tc-99 concentration. 

2,4 Technical Discussion – Ongoing and future NRC research activities by the Center for 

Nuclear Waste Regulatory Analyses (CNWRA): 

2.4.1 Observation Scope: 

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

compliance with 10 CFR 61.41 and 10 CFR 61.42. This 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 3.04 (Effect of Curing Temperature on Saltstone Hydraulic Properties) 

• MA5 (Waste Form Chemical Degradation): 

o MF 5.02 (Chemical Reduction of Tc by Saltstone) 

o MF 5.05 (Potential for Short Term Rinse-Release from Saltstone) 

2.4.2 Observation Results: 

The NRC staff presented an overview of the research that the Center for Nuclear Waste 

Regulatory Analyses (CNWRA was performing for the NRC. The goals of that research are to 

evaluate the following four issues: 

• presence of a persistent oxidized fraction of Tc in saltstone; 

• spatial distribution of Tc and reducing agents after exposure to artificial groundwater; 

• correlation between reducing capacity and Tc retention in saltstone; and 

• solubility of Tc under chemically reducing conditions. 

The NRC staff presented an overview of the planned use of a flexible-walled permeameter to 

study matrix flow through saltstone samples to be prepared in a variety of ways. The NRC staff 

presented a matrix of parameters to be varied during sample preparation, including oxygen in 
- 8 - 

saltstone solution, grinding of blast furnace slag, oxygen in the mixing atmosphere, temperature 

ramp rate, highest curing temperature, and cure time. 

The DOE provided the NRC staff with the following observations and suggestions about the 

NRC staff experimental plans, including about the NRC samples: 

• saltstone simulant preparation should follow the ARP/MCU formulation; 

• preparation of saltstone simulant can be challenging; 

• humidity should be maintained at or close to 100 percent during curing; 

• saltstone simulant following the Salt Waste Processing Facility formulation should be 

compared against the baseline experiment; 

• Sample 2 and Sample 3 should be cured under 0 parts-per-million (ppm) oxygen; 

• temperature curing profile should mimic actual as-emplaced saltstone conditions as 

much as possible; 

• peak cure temperature (e.g., 65°C (149°F)) should not be maintained longer than 

observed in field; 

• ramping down from maximum curing temperature is important; 

• channeling through samples is potential concern with use of permeameter; 

• steps should be taken to minimize potential artifact of using permeatmeter; 

o NOTE: artifact means something in the experimental plan or implementation of 

the experimental plan that leads to misinterpretation of results of the experiment. 

• secondary purpose of permeameter is to measure hydraulic conductivity of samples; 

• larger diameter sample with shorter length allows more pore volumes to migrate through 

column in given amount of time; 

• Savannah River Ecology Laboratory is switching holder and sleeve to accommodate 

larger samples; 

• leachate analysis should include nitrite, which requires use of Tedlar bag to minimize 

oxygen contamination; and 

• preliminary saltstone simulants should be evaluated prior to producing matrix of 

saltstone simulant cores to verify that core samples are reasonably representative of 

saltstone grout. 

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 that technical discussion: 

• The DOE will attach the NRC presentation to Revision 1 of the DOE presentation. 

 
- 9 - 

• The DOE to provide the NRC staff with the Savannah River National Laboratory report 

on saltstone simulant preparation. 

• The DOE to provide the NRC staff with saltstone preparation (i.e., mixing) procedure(s). 

2.5 Technical Discussion – DOE sampling and analyses plan research status:

2.5.1 Observation Scope: 

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

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

to the following MA 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) 

2.5.2 Observation Results: 

The DOE provided a summary of the DOE 2014 critical property testing results and planned 

DOE 2015 critical property testing associated with the following topics and documents: 

• iodine (SREL Doc. R-14-0005); 

• oxidation rate of cementitious materials (SRRA042328SR); 

• technetium leaching from saltstone monoliths (SREL Doc. R-14-0006 and SREL Doc. 

R-14-0007); and 

• temperature effects on saltstone curing (VSL-14R3210-1). 

In response to an NRC staff question, the DOE clarified that the SREL Doc. R-14-0005 

document included work with cementitious materials, not just soils, as implied in the document 

title. That topic is discussed in more detail later in this onsite observation visit report. 

In the SREL Doc. R-14-007 document, the DOE described work to develop a method for 

performing dynamic leaching experiments for Tc, where a flexible-wall permeameter was used 

to force artificial groundwater through a simulated saltstone sample spiked with iodide and 

perrhenate. 

The DOE described a study relevant to the SRRA042328SR document where X-Ray Absorption 

Spectroscopy (XAS) methods were used to evaluate the oxidation state of Tc in saltstone cured 

for different times. The DOE noted that to be detectable with XAS, Tc was spiked in samples at 

~200 times the concentration than would be representative in saltstone. The DOE attributed the 

fraction of Tc remaining oxidized after 30 days of curing to the relatively high Tc concentration. 

The results were available for samples cured for three months, but the results were not yet 

available for samples cured for six months. 

 
- 10 - 

The DOE described results associated with the VSL-14R3210-1 document. The study 

examined the effects of ramping temperatures at different rates. The DOE indicated that 55°C 

(130°F) was the maximum temperature expected in SDS 6. The NRC staff questioned whether 

continuous pouring, which could occur when the Salt Waste Processing Facility would be 

operational, could increase that maximum temperature in the 375-foot diameter disposal 

structures (i.e., SDS 6 through SDS 12). The DOE indicated that it does not expect such a 

large temperature increase in any of those disposal structures. The DOE indicated that 

samples cured for 30 days had hydraulic conductivities of ~1.0 x 10-8 cm/s, but that samples 

cured for 90 days had hydraulic conductivities of approximately ~2.0 x 10-9 cm/s. In response to 

an NRC staff question, the DOE indicated that it considered 90 days to be the minimum curing 

time for a representative sample. The DOE noted that it usually saw a factor of ~six decrease in 

hydraulic conductivity between 30 days and 90 days of curing. 

The DOE summarized the status and future plans to sample cores from full-scale saltstone. 

The DOE plan will be to sample six cores from SDS 2A in April 2015. The samples are 

expected to be 2.0 meters (~6.0 feet) long. The DOE noted that originally the cores were 

expected to be ~1.07 meters (3.5 feet) long, but now the fill height of the 150-foot diameter 

disposal structures (i.e., SDS 2A, SDS 2B, SDS 3A, SDS 3B, SDS 5A, SDS 5B) was increased. 

Thus, the DOE now required a longer core to reach the sample at the correct height to 

correspond to the saltstone that was sampled during emplacement in SDS 2A. The DOE 

explained that one of the challenges of drilling such a longer core in SDS 2A was that it was 

composed of 17 lifts poured over a 10 month time period. The DOE explained that, as a drill is 

pulled out, the lifts may break free from one another and can misalign, which makes it difficult to 

insert the core extraction tool. The DOE explained that the core extraction tool was modified to 

help align the lifts. The DOE noted that the mockup work is no longer being conducted in the 

B25 box, as described in the SDF Observation 2015-01 Report. Instead, the mockup work is 

being performed in a pilot scale sample poured into a commercial sonotube. The DOE 

described work done to prepare for full-scale core drilling, including drilling without light in full 

personal protective equipment. The DOE indicated that the Tc oxidation state would be studied 

with field-emplaced core samples, but not in laboratory-produced samples because laboratory 

samples were not spiked with Tc. 

In response to an NRC staff question, the DOE indicated that it did not expect significant 

artifacts from core drilling. Microcracking could be an issue, but scoring along the external 

surfaces was not expected to cause significant artifacts because the pressure cuff used in the 

permeameter would eliminate the potential effects of scoring. 

The DOE explained that, after a core sample is taken, 1.2 meters (~4.0 feet) of the sample 

would be placed back in SDS 2A and 0.6 meters (~2.0 feet) would be sent to Savannah River 

National Laboratory (SRNL) in a specialized holder. To limit oxidation, the sample would be 

saturated with water and the sampleholder would be purged with nitrogen gas. The DOE 

explained that, it had initially tried shipping the sample with oxygen absorbers, instead of 

purging the sample holder, but the oxygen absorbers did not work quickly enough. To remove 

the core from the sampleholder, the whole sampleholder would be placed in an airlock chamber 

and the core sample would be removed from the sampleholder in a nitrogen gas atmosphere. 

All sample preparation would occur in the airlock chamber in an “inert” environment. In this 

report, the NRC notes that this is a correction to what is described in the DOE presentation for 

SDF Observation 2015-01. 
- 11 - 

In response to an NRC staff question, the DOE explained that, cores would be taken from three 

locations at the top of SDS 2A and that each location has a pair of sampling ports. For each of 

the three pairs, one port would be used for a camera and two cores would be taken from the 

other port. 

In response to an NRC staff question, the DOE indicated that, it does not plan to measure 

reducing capacity of the core samples. The DOE plans to conduct dynamic leaching 

experiments and would measure density, porosity, moisture content, saturated hydraulic 

conductivity, Tc oxidation state, and sorption coefficients (Kds) as well as compositional analysis 

on the radioactive samples, including total Tc, strontium, iodine, selenium, and radium. The 

DOE explained that, for Kd tests, the samples will be crushed and leached and then the solution 

concentration would be measured. The DOE agreed with an NRC staff comment that, in that 

type of experiment, if different solid-to-liquid ratios yielded the same leached concentration of 

Tc, then the result would indicate a solubility limit rather than sorption. The NRC staff indicated 

that, if the blast furnace slag is crushed, then it could become more reactive than field-scale 

blast furnace slag because crushing could remove any oxidized rind that might limit reactivity of 

the slag. In response to that NRC staff comment, the DOE indicated that, it was still working out 

that experimental detail. The NRC staff understood that the purpose of the DOE sampling and 

analyses plan was to determine whether the laboratory results could accurately mimic the field 

scale results and that purpose could be accomplished as long as the blast furnace slag was 

treated the same way for measurements in both laboratory and field samples. 

In response to an NRC staff question about visual differences in laboratory and field-scale cored 

samples, the DOE indicated that the color difference was attributable to the oxidation state of 

iron. The DOE cited a report (SRRA042328SR) that indicated that the sulfur in blast furnace 

slag is oxidized to sulfate rapidly in salt solution. The NRC staff indicated that, in CNWRA 

experiments, a white coating formed on the samples and the CNWRA believed that was due to 

a carbonation reaction because the coating bubbled when acid was applied. The DOE 

indicated that the color change will occur within minutes of a sample being exposed to air. 

In response to an NRC staff question, the DOE indicated that, it was not sure how long samples 

would be archived, but that they would be saved in an inert environment. In response to an 

NRC staff question, the DOE explained that, sometime in the future, the holes in the saltstone 

monolith left by the core samples would be filled in with the clean cap. 

2.5.3 Conclusions and Follow-Up Action Items: 

The NRC staff concluded that the thoroughness with which the DOE has planned core sample 

handling appears to be promising for useful research results. The NRC staff will continue to 

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

activities. No Follow-Up Action Items resulted from that technical discussion. 

 
- 12 - 

2.6 Technical Discussion – Iodine sorption and Tc solubility:

2.6.1 Observation Scope: 

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

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

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

• MA 5 (Waste Form Chemical Degradation): 

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

• MA 10 (Performance Assessment Model Revisions): 

o MF 10.04 (Kd Values for Saltstone) 

o MF 10.06 (Kd Values for Disposal Structure Concrete) 

o MF 10.09 (Kd Values for SRS Soil) 

2.6.2 Observation Results: 

The NRC staff and the DOE discussed the solubility of Tc(IV) in saltstone. The DOE explained 

that the Almond and Kaplan reference (SRNL-STI-2010-00667), which the NRC staff previously 

considered in the NRC 2012 TER [ML121170309], provided a solubility measurement for Tc(IV) 

of 1 x 10-10 Molarity. The NRC staff indicated that it would review the conditions of that 

measurement and evaluate the relevance to field-emplaced saltstone. In response to the NRC 

staff questions about the differences between the results of Cantrell and Williams [PNNL-21723] 

and the results of Almond and Kaplan, the DOE (i.e., Dr. Kaplan himself) attributed the lower 

solubility observed by Almond and Kaplan to the following two phenomena: (1) high solubility 

value observed by Cantrell and Williams (1.5 x 10-6 M) was attributed to the high pH of the 

sample solution (i.e., 12.5), which would be representative of young concrete; and (2) study by 

Cantrell and Williams used a flow through system that had not achieved steady state. 

Dr. Kaplan indicated that the Almond and Kaplan study was based on a two to three year old 

field-emplaced saltstone core, which he indicated was a high quality sample. 

In response to an NRC staff question, the DOE indicated that the basis for the sorption 

coefficients for iodine used in the SDF FY14 Special Analysis document were from the 

Geochemical Data Package for Performance Assessment Calculations Related to the 

Savannah River Site (SRNL-STI-2009-00473). The DOE 2015 Performance Assessment 

Maintenance Implementation Plan (SRR-CWDA-2014-00108) indicated that the DOE will 

update the values in the Geochemical Data Package. The NRC staff asked Dr. Kaplan how he 

anticipated updating the values for iodine, and if he could provide context for differences 

between the values in the 2010 Geochemical Data Package and the lower sorption coefficients 

measured by Seaman and Chang (2014) (SREL Doc. R-14-0005). 

Dr. Kaplan discussed three studies performed on iodine sorption since 2010: (i) review paper, 

(ii) SREL experiments, and (iii) Hanford study: 

• Dr. Kaplan explained that one reason the SREL study may have detected less sorption 

than the other two studies was that it used iodine concentrations much greater than will 
- 13 - 

be present in saltstone (i.e., a 16,000 pCi/g spike used in SREL study, compared to 

7 pCi/g in saltstone). Dr. Kaplan hypothesized that the higher concentration of iodine 

had filled all of the sorption sites and left the majority of iodine unsorbed. 

• Regarding the Hanford study, Dr. Kaplan noted that he had observed coprecipitation of 

iodate in a calcium carbonate phase that was ~25 percent iodate by weight and that this 

could be a long-term process that was not adequately represented in such short-term 

experiments. 

In response to an NRC staff question, Dr. Kaplan indicated that, he expected to use one set of 

values to represent sorption to both concrete and saltstone in the next revision of the 

Geochemical Data Package because there was not enough data available to differentiate 

between the two conditions and that he is confident in the values provided for iodine sorption in 

SRS soil because they are consistent with the behavior of an Iodine-129 plume at SRS. 

In response to an NRC staff question, the DOE explained that, when the Geochemical Data 

Package is updated the effects on the revised values on the projected performance of the SDF 

will be addressed through an Unreviewed Waste Management Question Evaluation (UWMQE) 

or a revised Special Analysis, as appropriate, based on the significance of the changes. 

2.6.3 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 that technical discussion: 

• The DOE to provide the NRC staff with additional documentation relative to iodine Kd

values for concrete, including the European study and SRS F-Area iodine studies (soils). 

2.7 Technical Discussion – Tan Clay Confining Zone (TCCZ) structure and ZBG-2 well 

sample results: 

2.7.1 Observation Scope: 

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

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

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

• MA 8 (Environmental Monitoring): 

o MF 8.02 (Groundwater Monitoring) 

• MA 10 (Performance Assessment Model Revisions): 

o MF 10.02 (Defensibility of Conceptual Models) 

 
- 14 - 

2.7.2 Observation Results: 

The DOE discussed two new monitoring wells, ZBG-016D and ZBG-016C. The wells are close 

to each other and downgradient of Sedimentation Basin 4. ZBG-016D is above the TCCZ and 

ZBG-16C is screened below the TCCZ. The DOE indicated that no contamination has been 

detected in either well. In response to an NRC staff question, the DOE clarified that “no 

contamination” included nitrate and conductivity as well as gross beta and several other 

radiological measurements. 

In response to an NRC staff question, the DOE explained that well ZBG-2 would be sealed 

because its screened length extended into the top of the TCCZ, where it could act as a conduit 

of contamination into the lower aquifer zone. The DOE indicated that a new well would be 

installed nearby that would be screened above the TCCZ. The NRC staff pointed out that 

several screened lengths of other wells in the Z-area extended into the TCCZ and that the 

thickness between the screened interval and the boundary of the TCCZ may be too thin to 

prevent contaminant movement between the upper zone and the lower zone of the Upper Three 

Runs Aquifer (UTRA). The NRC staff asked if the DOE planned to close those wells too. The 

DOE explained that well ZBG-2 was a priority because contamination had been detected in it. 

The NRC staff questioned the DOE assumption that contamination was not present in the other 

locations in the Z Area and pointed out that there were no wells screened above the TCCZ in 

the other locations, which means that the DOE could not be sure if there was contamination in 

those other wells. In response, the DOE noted that in another location downgradient of SDS 4, 

a Direct Push Technology (DPT) sample pushed into the top of the TCCZ did not show elevated 

nitrate. The NRC staff pointed out that was in the same location and there were no wells 

screened above the TCCZ in the other locations. 

The DOE described a conceptual model where water from near SDS 4 would flow along the top 

of the TCCZ and into ZBG-2, which would act as a sump. At some places at SRS, the water 

table terminates in the upper zone of the UTRA and re-occurs in the lower zone of the UTRA. 

The NRC staff indicated that only two wells listed in the 2014 Z-Area Groundwater Monitoring 

Report were screened in the correct location to measure the water table [SRNS-TR-2014-

00283]. The DOE explained that much of the data came from other SRS areas, not the Z-area. 

The NRC staff expressed interest in whether the water above the TCCZ was interconnected or 

occurred in isolated areas. The DOE replied that the upper zone of the UTRA is not present in 

much of Z-Area and that the new well, ZBG-016D, is dry. The NRC staff indicated that there 

was insufficient data within the Z Area to know if the upper zone of the UTRA was saturated and 

that the temporal and spatial extent of a saturated zone in upper zone of the UTRA in Z-Area 

could have a significant role in influencing potential contaminate transport. The NRC staff 

suggested that the DOE could update a spreadsheet that it had previously provided to the NRC 

staff that included historical data to support the thickness of the upper zone of the UTRA over 

time, which included data from 1987 to 2007 (RSS-REG-2008-00025). 

The NRC staff asked the DOE about the source of the contamination observed at ZBG-2. The 

DOE indicated that: (i) it continued to believe that the contamination was attributable to 

weeping from the walls of SDS 4 in about the year 2000; (ii) SDS 4 had been effectively isolated 
- 15 - 

and that it was not an ongoing source of contamination; and (iii) fall in contaminant 

concentrations was caused by sample dilution with heavy rainfall. 

The DOE described plans to use DPT and Cone Penetrometer Test (CPT) measurements to 

characterize the top of the TCCZ and that much of the work would be done in April and May of 

2015. The NRC staff indicated that, it would be useful to understand the vertical gradient 

between the upper and lower zones of the UTRA as well. The DOE responded that there are 

not many well pairs available in Z-Area to measure the vertical gradient and that the new well 

pair that will replace ZBG-2 will provide some data. The vertical gradient is modeled as 

~3.0 meters (10 feet) in the General Separations Area and was typically modeled as 

~1.5 meters (5.0 feet) in Z-Area. The NRC staff and the DOE agreed that the gradient 

depended on the climate in recent years. 

In response to an NRC staff question, the DOE indicated that, it did not expect any effect on 

surficial aquifers from the three new extraction wells installed into the Congaree Aquifer to 

supply water for hydrotesting of the 375-foot disposal structures (i.e., SDS 6 through SDS 12). 

The site already has extraction wells at ~150 meters (500 feet) depth, screened over 50 meters 

(150 feet), which pump 25 liters per second (400 gallons per minute) and show no detectable 

drawdown. Before the DOE uses the three new extraction wells, the DOE would do an eighthour test of pumping all three wells at once to measure drawdown. 

The NRC staff expressed concern that the DOE may not be adequately considering an alternate 

conceptual model, applicable to a potentially wetter future climate, in which the upper zone of 

the UTRA is the main source of drinking water and contamination would be concentrated in the 

upper zone of the UTRA by the TCCZ. The NRC staff suggested that could be the topic of a 

future technical teleconference call. 

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 that technical discussion: 

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

o historical data on Z-Area wells. 

 water thickness of upper zone of the Upper Three Runs Aquifer over time 

o 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 (including 

wells beyond Z-Area as applicable). 

• The DOE to provide the NRC staff with an updated version of SRS-REG-2008-00025. 

 
- 16 - 

2.8 Technical Discussion – SDS 3A sump Unreviewed Waste Disposal Question Evaluation 

(UWDQE): 

2.8.1 Observation Scope: 

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

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

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

• MA 6 (Disposal Structure Performance): 

o MF 6.05 (Integrity of Non-cementitious materials) 

• MA 8 (Environmental Monitoring): 

o MF 8.01(Leak Detection) 

2.8.2 Observation Results: 

The NRC staff and the DOE discussed the results of the Unreviewed Waste Disposal Question 

Evaluation (UWDQE) “Evaluation of Potential Breach of Side Wall High Density Polyethylene 

(HDPE) Liner on Saltstone Disposal Unit Cell 3A” (SRR-CWDA-2014-00070). 

In response to the NRC staff questions about the geonet fabric, DOE explained that, the geonet 

is ~1.0 centimeters (~0.39 inches) thick and it sits on top of the HDPE on the Geosynthetic Clay 

Liner (GCL) between the upper and lower mud mats. The geonet allows any water that might 

drain from SDS 3A to enter the sump box. In response to the NRC staff and the SCDHEC staff 

questions, the DOE explained that, a test for water tightness was performed on the SDS 3A 

sump box, but the test was not performed on the connections of the HDPE to the SDS 3A sump 

box. 

The DOE provided an example of a seam welded section of HDPE and explained that, seam 

welds on the flat HDPE in the closure cap and below the drainage layer were expected to be 

more robust than the extrusion welds around the SDS 3A sump. The DOE suggested that the 

most likely explanation was a failure of an extrusion weld. The NRC staff noted that, in the 

UWDQE, the DOE had not ruled out an HDPE tear or a failure of a seam weld. The NRC staff 

expressed concern that the UWDQE only evaluated the potential impacts of a breach in the 

HDPE around SDS 3A and did not evaluate the potential impact of a breach in the HDPE layer 

in either the closure cap or below the drainage layer above SDS 3A. In response, the DOE 

explained that, it expected better protection of the HDPE in the cover and below the drainage 

layers. 

The DOE explained that, a camera was used to examine the SDS 3A sump and no major flaws 

were found in the HDPE. The DOE was not surprised because a small flaw could be 

responsible for the slow rate of water infiltration into the SDS 3A sump box. In response to an 

NRC staff question, the DOE explained that, there is a water level indicator in the SDS 3A sump 

box and that water is pumped out as needed. 

 
- 17 - 

The DOE explained that, the SDS 3A sump box still functions as a leak collection system and 

that concentrations of radionuclides in the collected water were still measured. The NRC staff 

and the DOE agreed that the concentrations would be diluted with rainwater, but the 

measurements could still show how much activity was collected. The DOE indicated that the pH 

of the collected water provided a good indication of the relative proportions of rainwater and 

leachate. 

2.8.3 Conclusions and Follow-Up Action Items: 

The NRC staff concluded that the analysis in the UWDQE did not cover potential effects of a 

flaw in the HDPE or a flaw in an HDPE seam in the drainage layers in the closure cap, or a flaw 

in the engineered layers above each disposal structure. The NRC staff concluded that those 

omissions added uncertainty to the DOE projections of long-term performance of those features. 

The NRC staff will continue to monitor disposal structure performance, including the projected 

performance of drainage layers. The NRC staff will continue to monitor DOE SDF activities. No 

Follow-Up Action Items resulted from that technical discussion. 

2.9 Technical Discussion – PORFLOW modeling for the DOE SDF FY14 Special Analysis 

Document: 

2.9.1 Observation Scope: 

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

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

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

• MA 5 (Waste Form Chemical Degradation): 

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

• MA 8 (Environmental Monitoring): 

o MF 8.02 (Groundwater Monitoring) 

• MA 10 (Performance Assessment Model Revisions): 

o MF 10.01 (Implementation of Conceptual Models) 

o MF 10.02 (Defensibility of Conceptual Models) 

2.9.2 Observation Results: 

This technical discussion included both intermediate model results for Tc release and the 

conceptual model for flow through the lower unsaturated zone and saturated zone. 

To address the NRC staff questions about projected Tc release in the PORFLOW model, the 

DOE summarized the main points from the technical report, “Sensitivity Analysis for Saltstone 

Disposal Unit Column Degradation Analyses” (SRNL-STI-2014-00505). 

The DOE explained that, in the PORFLOW model, a zone of slower oxidation, which the DOE 

called “oxidation shadow,” occurs near the walls and roof support columns of a disposal 
- 18 - 

structure because they are more permeable than the saltstone and they divert flow from the 

saltstone. The NRC staff suggested that, the oxidation shadows would not occur if the 

PORFLOW model included the effects of oxidation due to diffusion of oxygen into the saltstone 

from soil gas. The DOE indicated that gas-phase oxygen was not included in the model 

because the saltstone was assumed to be fully saturated. The NRC staff indicated that there 

was not adequate model support to preclude the possibility of unsaturated fractures in the 

saltstone monolith. The NRC staff reiterated concerns that fractures due to mechanical 

degradation should be included in the evaluation case. 

The DOE continued to review intermediate model results from the same report (SRNL-STI2014-00505), including a series of figures that showed projected Tc in the aqueous and solid 

phases in different locations in the saltstone waste form and disposal structure. The DOE 

presented results that showed that most of the Tc release occurred through the disposal 

structure basemats, rather than through the walls. The DOE presented intermediate flow results 

from the same report (SRNL-STI-2014-00505). The DOE explained that, a small amount of 

water flows back into the disposal structures through the walls because most of the infiltrating 

water is shed around the disposal structures through the sand drainage layer. 

To address the NRC staff questions about the conceptual model of flow through the engineered 

barriers and unsaturated zone, the DOE discussed flow beginning at the land surface and 

flowing through both the engineered barriers and the disposal structure. The DOE explained 

the context of the saltstone PORFLOW model in the context of the PORFLOW model of the 

larger area, which is the General Separations Area (GSA) model. The DOE explained that, in 

the saltstone PORFLOW model, it assumed that there were two soil types in the unsaturated 

zone, both native soil and backfill. In general, backfill was assumed to contain less clay and to 

have a lower saturated hydraulic conductivity. Unsaturated flow was modeled with the Richards 

Equation and that the characteristic curves used were provided in the SDF FY14 Special 

Analysis document. 

The NRC staff asked the DOE about the flow and transport through the various components of 

the disposal structures (e.g., concrete floor, bearing pad, mud mat, geosynthetic clay liner). The 

NRC staff asked the DOE about the significance to performance of each component and the 

major differences between the 375-foot disposal structures (i.e., SDS 6 through SDS 12) and 

the other two types of disposal structures (i.e., SDS 1, SDS 4, SDS 2A, SDS 2B, SDS 3A, SDS 

3B, SDS 5A, SDS 5B). The NRC staff asked the DOE if flow through the components occurred 

in a homogeneous manner or if the water collected at certain locations and then followed in 

preferential flow paths until released at the bottom of the lower mud mat. The DOE did not 

discuss a more detailed conceptual model that differentiated each disposal structure 

component, other than the consideration of fast flow paths through construction joints. The 

NRC staff agreed with DOE that the PORFLOW model showed that the release of contaminants 

from the disposal structure was not laterally uniform. However, the NRC staff indicated that, a 

more realistic representation of the various disposal structure features may result in an even 

less uniform release. The NRC staff indicated that, an alternative conceptual model could have 

infiltrating water with higher flow rates and/or greater concentrations released at fewer 

preferential locations from the lower mud mat. 

In response to an NRC staff question about credit given for the unsaturated zone in the 

PORFLOW model, the DOE explained that, although water spends a relatively short amount of 
- 19 - 

time (e.g., 10 years or fewer) in the unsaturated zone, some contaminants, such as plutonium, 

are significantly delayed by sorption. In response to an NRC staff question about whether the 

unsaturated zone thickness was modeled as a constant, the DOE indicated that a different 

thickness was used for each type of disposal structure, but that each of those thicknesses was 

assumed to be uniform across the SDF. The DOE referred to a figure in the SDF FY14 Special 

Analysis document that showed the thickness used for each type of disposal structure, 

contrasted with the best estimate of the unsaturated zone thickness in different parts of the 

SDF. 

In response to an NRC staff question, the DOE explained that, the flux from the unsaturated 

zone model was placed into the first grid block that was fully saturated. In response to an NRC 

staff question, the DOE clarified that, the grid block does not change with time. The NRC staff 

and the DOE reviewed the discussion of whether the water table is in the upper or lower zone of 

the UTRA. The NRC staff asked if the DOE expected changes in the water table elevation due 

to the closure cap. The DOE indicated that it was possible, but that flow through the closure 

cap was projected to return to near normal infiltration rates within several hundred years of site 

closure. 

2.9.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor the DOE SDF PORFLOW model as part of its review of 

the SDF FY14 Special Analysis document. The NRC staff will continue to monitor DOE SDF 

activities. No Follow-Up Action Items resulted from that technical discussion. 

2.10 Technical Discussion – GoldSim modeling for the DOE SDF FY14 Special Analysis 

Document: 

2.10.1 Observation Scope: 

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

compliance with 10 CFR 61.41 and 10 CFR 61.42. This 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) 

2.10.2 Observation Results: 

The NRC staff and the DOE reviewed the file locations for model files associated with the 

GoldSim Model for the SDF FY14 Special Analysis document. The DOE clarified that, results 

from Tc were run in a separate model from the model used for other radionuclides. The DOE 

explained that, a Dynamic Link Library (DLL) identified as “TS PROC” was needed to send 

results from each submodel to the main GoldSim model. The NRC staff and the DOE 

discussed the file locations needed for the DLL and submodel files to allow the model to 

execute. 

 
- 20 - 

A smaller group of the NRC staff and the DOE reviewed individual model containers in the 

GoldSim model and discussed the purpose and implementation of each to understand how the 

DOE model worked. 

2.10.3 Conclusions and Follow-Up Action Items: 

The NRC staff will continue to monitor the DOE SDF GoldSim model as part of its review of the 

SDF FY14 Special Analysis document. The NRC staff will continue to monitor DOE SDF 

activities. No Follow-Up Action Items resulted from that 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 2015-01 will be used for multiple NRC 

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

document, and future onsite observation visits, based on the topics discussed. There is no 

change to the NRC staff overall conclusions from the SDF TER regarding compliance of DOE 

disposal actions with the 10 CFR Part 61 performance objectives. 

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

SDF Observation 2015-01 is the second onsite observation visit under SDF Monitoring Plan, 

Rev. 1. The NRC staff did not close any monitoring factors during SDF Observation 2015-01. 

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 have been rolled into the Monitoring Factors in SDF Monitoring 

Plan, Rev.1. The NRC staff did not open any new Open Issues during SDF 2015-01. 

Therefore, there are currently no SDF Open Issues. 

3.4 Status of Open Follow-up Action Items from Previous SDF Onsite Observation Visit 

Reports: 

There were fifteen previous NRC SDF onsite observation visits. All Follow-Up Action Items from 

reports for those previous SDF onsite observation visits have been closed. 

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

All Follow-Up Action Items from previous clarification teleconference calls have been closed. 

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

The table below contains the nine Follow-Up Action Items that were open during this onsite 

observation visit, including a unique NRC identifier for each Follow-Up Action Item: 
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Unique Identifier Follow-Up Action Item 

SDF-CY15-01-001 • The DOE to provide the NRC staff with additional photos of 

construction of SDS 6 including: 

o photos contained in the laminated card utilized during 

tour; 

o aerial photos; 

o column rebar photos of the following: 

 column pedestal to floor 

 column to pedestal 

 column to roof 

o intersection of roof joints with waterstop; 

o wall bearing pads; 

o wall joints (e.g., waterstop, bearing pads); 

o tension wires; and 

o wall to roof connections. 

SDF-CY15-01-002 • The DOE to provide the NRC staff with a table containing 

Tank 50 sample quarterly report historical information. 

SDF-CY15-01-003 • The DOE to provide the NRC staff with the Salt Batch 8 

qualification report, when available, and information on the 

timing of processing future batches, including anticipated 

increase in Tc-99 concentration. 

SDF-CY15-01-004 • The DOE will attach the NRC presentation to Revision 1 of the 

DOE presentation. 

SDF-CY15-01-005 • The DOE to provide the NRC staff with the Savannah River 

National Laboratory report on saltstone simulant preparation. 

SDF-CY15-01-006 • The DOE to provide the NRC staff with saltstone preparation 

(i.e., mixing) procedure(s). 

SDF-CY15-01-007 • The DOE to provide the NRC staff with additional 

documentation relative to iodine Kd values for concrete, 

including the European study and SRS F-Area iodine studies 

(soils). 

SDF-CY15-01-008 • The DOE to provide the NRC staff with additional groundwater 

data relative to: 

o historical data on Z-Area wells 

 water thickness of upper zone of the Upper 

Three Runs Aquifer over time 

o 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 

(including wells beyond Z-Area as applicable) 

SDF-CY15-01-009 • The DOE to provide the NRC staff with an updated version of 

SRS-REG-2008-00025. 

 
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3.7 Issuance of NRC Technical Review Reports: 

Between SDF Observation 2014-01 and SDF Observation 2015-01, the NRC did not issue any 

SDF Technical Review Reports via memorandum. 

4.0 PARTICIPANTS:

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

George 

Alexander 

Justin Koon Dan Ferguson Tim Coffield Greg Flach 

Hans Arlt Gregory O’Quinn Philip Prater Steve Hommel Daniel Kaplan 

Terrence 

Brimfield 

Andrea Skinner Sherri Ross Barry Lester 

Harry Felsher Patricia Suggs Bruce Long SRNS

Christepher 

McKenney 

 Linda Suttora Larry Romanowski Bob Aylward 

Karen Pinkston Armanda Watson Kent Rosenberger Gerald Blount 

A. Christianne 

Ridge 

 Steve Simner Mike Griffith 

 Dan Skiff Terry Killeen 

 F. Malcom Smith Cathy Lewis 

 Steve Thomas 

 David Watkins 

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. 

Papathanassiu, A.E., et al., VSL-14R3210, “Final Report Saltstone Curing Assessment, 

Vitreous State Laboratory, The Catholic University of America, Revision 0, March 2014. 

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, “U.S. Department of Energy Draft Basis for Section 3116 

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

_____ DOE-WD-2005-001, Rev. 1, “U.S. Department of Energy Basis for Section 3116 

Determination Salt Waste Disposal at the Savannah River Site,” January 2006. ML102850319. 
- 23 - 

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

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

_____ “Response to Letter of Concern (Type-IV) Regarding U.S. Department of Energy 

Disposal Activities at the Savannah River Site Saltstone Disposal Facility,” July 2012. 

ML12198A258. 

_____ “Additional Response to 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. 

_____ SREL Doc.: R-14-0005, Rev. 0, “Impact of Cementitious Material Leachate on Iodine 

Partitioning,” September 2014. ML15030A112. 

_____ SREL Doc.: R-14-0006, Rev. 0, “Chemical and Physical Properties of Saltstone as 

Impacted by Curing Duration,” September 2014. ML15030A129. 

_____ SREL Doc.: R-14-0007, Rev, 0, “Dynamic Leaching Characterization of Saltstone,” 

September 2014. ML15027A326. 

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

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

_____ SRR-CWDA-2012-00108, Rev. 0, “NRC Salt Waste Monitoring Updates,” August 2012. 

ML12235A359. 

_____ SRR-CWDA-2014-00070, Rev 0, “Evaluation of Potential Breach of Side Wall High 

Density Polyethylene (HDPE) Liner on Saltstone Disposal Unit Cell 3A,” July 2014. 

ML14322A315. 

_____ SRR-CWDA-2015-00011, Rev. 1, “Presentation for Savannah River Site Salt Waste 

Disposal NRC Onsite Observation Visit,” February 2015. ML15070A359. 

_____ SRRA042328SR, Rev. 0, “Examination of Tc, S, and Fe Speciation within Saltstone,” 

August 2014. ML15103A323. 

_____ SRNL-STI-2009-00473, Rev. 0, “Geochemical Data Package for Performance 

Assessment Calculations Related to the Savannah River Site,” March 2010. ML11320386. 

_____ SRNL-STI-2011-00551, Rev 0, “Tanks 18 and 19-F Structural Flowable Grout Fill 

Material Evaluation and Recommendations,” September 2011. ML13078A276. 

_____ SRNL-STI-2014-00505, Rev 0, “Sensitivity Analysis for Saltstone Disposal Unit Column 

Degradation Analyses,” October 2014. ML15103A318. 

_____ SRNS-TR-2014-00104, Rev 0, “Z-Area Saltstone Disposal Facility Groundwater 

Monitoring Midyear Report For 2014 (U),” July 2014. ML14221A291. 
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_____ VSL-14R3210-1, Rev 0, “Saltstone Curing Assessment,” February 2014. ML14190A253 

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

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

_____ “NRC Staff Guidance for Activities Related to U.S. Department of Energy 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 U.S. Department of Energy 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. 

_____ “U.S. Nuclear Regulatory Commission Plan for Monitoring Disposal Actions Taken by the 

U.S. Department of Energy at the Savannah River Site Saltstone Disposal Facility in 

Accordance with the National Defense Authorization Act for Fiscal Year 2005,” Rev. 1, 

September 2013. ML13100A076. 

_____ “Onsite Observation Guidance for February 4 – 5, 2015, Monitoring Visit to the Savannah 

River Site, Saltstone Disposal Facility,” December 5, 2014. ML14321A534. 

_____ “U.S. NRC Staff Comments and Requests for Additional Information on the "Fiscal Year 

2013 Special Analysis for the Saltstone Disposal Facility at the Savannah River Site,” SRRCWDA-2013-00062, Rev. 2,” June 13, 2014. ML14148A153.