February 15, 2013 

Ms. Sonitza Blanco 

Acting Director 

Waste Disposition Programs Division 

U.S. Department of Energy 

Savannah River Operations Office 

P.O. Box A 

Aiken, SC 29802 

SUBJECT: U.S. NUCLEAR REGULATORY COMMISSION DECEMBER 6, 2012, ONSITE 

OBSERVATION VISIT REPORT FOR THE SAVANNAH RIVER SITE SALTSTONE 

DISPOSAL FACILITY (DOCKET NO. PROJ0734) 

Dear Ms. Blanco: 

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

observation visit on December 6, 2012, at the Savannah River Site (SRS) Saltstone Disposal 

Facility (SDF). The 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 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 10 CFR Part 61, 

Subpart C. The activities conducted during the visit were consistent with those described in the 

NRC monitoring plan for salt waste disposal at SRS (dated May 3, 2007) and the NRC staff 

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

On every onsite observation visit to SRS, NRC is focused on assessing compliance with four 

performance objectives in 10 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). 

On April 30, 2012, NRC issued both a Technical Evaluation Report (TER) [available via the 

NRC’s 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. The TER concluded that NRC did not have reasonable assurance that salt 

waste disposal at the SDF met the performance objective §61.41. The Type IV Letter of 

Concern formally communicated NRC’s concerns to both DOE and the South Carolina 

Department of Health and Environmental Control. 
S. Blanco 2 

DOE provided responses to the Type IV Letter to NRC in two submittals. These submittals 

included an updated technetium-99 (Tc-99) inventory projection for the newly constructed SRS 

saltstone disposal structures1

; and information about DOE Case K and K1 uncertainty and 

sensitivity analyses. In August 2012, NRC issued a letter of acknowledgement [ML12213A447] 

stating that a letter to the U.S. Congress (Type II) is not needed at this time. Based on the 

NRC’s TER analyses and DOE’s revised Tc-99 inventory, the staff determined that, if DOE’s 

new projected Tc-99 inventory for the newly constructed disposal structures is correct, then it is 

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 December 2012 onsite observation visit focused on the technical concerns described in the 

NRC 2012 TER. There are no new open issues resulting from that visit. Open issues that had 

been identified earlier have been rolled into the concerns identified by NRC in the 2012 TER. 

All NRC concerns will be rolled into the monitoring factors in the revised monitoring plan that is 

being drafted by NRC. 

The observation addressed a subset of the concerns raised in the 2012 TER. During the 

observation, staff was encouraged by DOE’s progress in a research plan that will provide useful 

information about risk-significant aspects related to SDF performance. The DOE and NRC 

continue to work in the monitoring process to resolve all outstanding issues that led to issuance 

of the Type IV Letter of Concern. In accordance with the requirements of NDAA, NRC will 

continue to monitor DOE disposal actions at SRS. 

Shortly before the observation, DOE requested a public meeting for January 2013 to discuss a 

revised model with updated parameterization in addition to continued discussions about 

progress in research related to the concerns identified in the NRC’s TER. In addition to DOE 

providing details about its revised model, some of the technical documents discussed during 

this observation were discussed in the January 17, 2013 public meeting. For details of the 

January 17, 2013 public meeting, please refer to the meeting summary at ADAMS Accession 

Number ML13025A038. 

 

 

1

 Inventory projections described in DOE’s response to NRC’s Type IV Letter are listed in reference to 

Disposal Structures (Cells) 2A, 2B, 3A, 3B, 5A, and 5B. Throughout this report, these structures will be 

referred to as the “newly constructed” saltstone disposal structures. 
S. Blanco 3 

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

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

Sincerely, 

/RA/ K. Hsueh for A. Mohseni 

Aby Mohseni, Deputy Director 

Environmental Protection and 

 Performance Assessment Directorate 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Onsite Observation Visit Report 

cc w /enclosure: 

WIR Service List 
S. Blanco 3 

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

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

Sincerely, 

Aby Mohseni, Deputy Director 

Environmental Protection and 

 Performance Assessment Directorate 

Division of Waste Management 

 and Environmental Protection 

Office of Federal and State Materials 

 and Environmental Management Programs 

Enclosure: 

NRC Onsite Observation Visit Report 

cc w /enclosure: 

WIR Service List 

DISTRIBUTION: GAlexander ARidge KPinkston JShaffner 

ML13010A499 

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

NAME NDevaser ARidge AWalker-Smith CMcKenney GSuber KHsueh for 

AMohseni 

DATE 1/11/13 1/24/13 1/10/13 1/24/13 2/5/13 2/15/13 

OFFICIAL RECORD COPY
WIR Service List 

Glenn Carroll, Coordinator 

Nuclear Watch South 

P.O. Box 8574 

Atlanta, GA 31106 

Tom Clements, Nonproliferation Policy 

Director 

Alliance for Nuclear Accountability 

1112 Florence Street 

Columbia, SC 29201 

Jim Hardeman, Manager 

Environmental Radiation Program 

Environmental Protection Division 

Georgia Department of Natural Resources 

4220 International Parkway, Suite 100 

Atlanta, GA 30354 

Karen Patterson, Environmental 

Appointment 

Governors' Nuclear Advisory Council 

 and Tetra Tech NUS 

900 Trail Road 

Aiken, SC 29803-5297 

Bobbie Paul, Executive Director 

Georgia Womens Action for New Directions 

250 Georgia Ave., SE 

Suite 202 

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 

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 

Thomas Saporito, Executive Director 

P.O. Box 8413 

Jupiter, FL 33468 

John J. Schnabel 

Saltstone Project Inspector, 

 Professional Engineer 

Division of Mining and Solid Waste 

 Management 

Bureau of Land and Waste Management 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1208 

S. Wilson 

Federal Facilities Liaison 

Environmental Quality Control 

Administration 

South Carolina Department of Health 

 and Environmental Control 

2600 Bull Street 

Columbia, SC 29201-1708
Enclosure 

U.S. NUCLEAR REGULATORY COMMISSION DECEMBER 6, 2012, ONSITE 

OBSERVATION VISIT REPORT FOR THE SAVANNAH RIVER SITE SALTSTONE 

DISPOSAL FACILITY 

EXECUTIVE SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) staff conducted its 13th onsite observation 

visit, Observation 2012-02, to the Saltstone Disposal Facility (SDF) at the Savannah River Site 

(SRS) on December 6, 2012. On every onsite observation visit to SRS, NRC focuses on 

assessing compliance with four performance objectives in 10 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). 

During Observation 2012-02, NRC focused on information regarding the April 30, 2012, NRC 

Technical Evaluation Report (TER) and associated Type IV Letter of Concern, where NRC 

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

performance objectives in 10 CFR Part 61, specifically §61.41. NRC performs monitoring 

activities in coordination with the State, so staff from the South Carolina Department of Health 

and Environmental Control (SC DHEC) also participated in this visit. 

During Observation 2012-02, NRC staff and U.S. Department of Energy (DOE) staff (including 

DOE contractors, Savannah River Remediation (SRR) throughout this report), discussed salt 

waste processing and the details of recent research conducted by DOE, related to issues 

identified in NRC’s TER. In addition, DOE provided NRC staff a brief tour of the SDF, including 

closer views of the newly constructed SRS saltstone disposal structures2

. This report provides 

a description of the NRC activities during Observation 2012-02, including observations that NRC 

staff made during the visit. 

There are no new Open Issues3

 resulting from Observation 2012-02. NRC staff received 

documents and a DOE presentation that pertained to the activities to be observed. The 

presentation that DOE provided to NRC staff and the documents provided by DOE for 

discussion at the observation are accessible via the NRC’s document repository, the 

Agencywide Documents Access and Management System (ADAMS), via accession number 

ML12345A110. 

Observation 2012-02 addressed a subset of the concerns raised in the 2012 TER. During the 

observation, staff was encouraged by DOE’s progress in conducting research that provides 

useful information. The DOE and NRC continue to work in the monitoring process to resolve all 

outstanding issues that led to issuance of the NRC’s Type IV Letter of Concern. 

 

2

 Inventory projections described in DOE’s response to NRC’s Type IV Letter are listed in reference to 

Disposal Structures (Cells) 2A, 2B, 3A, 3B, 5A, and 5B. Throughout this report, these structures will be 

referred to as the “newly constructed” saltstone disposal structures. 3

 The previous Open Issues are now rolled into the concerns identified by NRC in the 2012 TER. Those 

NRC concerns will be rolled into the monitoring factors in the revised monitoring plan that is being drafted 

by NRC. 
A summary of NRC staff observations and conclusions in those areas is provided below: 

• Previous Observation Follow-up

DOE provided a status of follow-up actions from the August 2012 observation 

(NRC, 2012e). This included a list of 14 items or topics, all of which were discussed, 11 of 

which were completed (closed), and 3 of which were discussed and an estimated 

completion date was provided. Discussions of the three remaining items will continue at the 

next onsite observation. Two new follow-up actions came from the discussion on Salt 

Batch 7 Tc-99 concentrations which will also be discussed at the next observation. 

• SDF Operation Details

DOE provided NRC staff with details of the disposal activities. During September and 

October 2012, approximately 4.2 million liters (1.1 million gallons) of salt waste was 

disposed into Saltstone Disposal Structure 2B from Tank 50. This is the first saltstone 

disposed of in the new design as presented in the 2009 Performance Assessment (PA) 

(SRR-CWDA-2009-00017). 

• Technical Discussion – Performance Assessment Maintenance Research Activities

NRC and DOE staff discussed DOE Performance Assessment Maintenance Research 

Activities, including Operating Window Property Testing (SRNL-STI-2012-00558), Tc-99 

Solubility and Kd Studies (PNNL-21723 and SRNL-STI-2012-00596), Method Evaluation for 

Measuring Oxidation Front Movement (SRNL-STI-2012-00468, Rev. 0), Fracture Transport 

(SRNL-STI-2012-00267), Formed Core Sampling (SRNL-STI-2012-00551), Review of 

Concrete Biodeterioration (SRNL-STI-2012-00435), and Comparison of Wasteform Mixtures 

(SIMCO, 2012). 

Of these topics, the most time was spent on the discussion of the operating window property 

testing and the Tc-99 solubility and Kd studies. Regarding the operating window property 

testing, the NRC staff asked several questions about the incorporation of flush water into the 

emplaced saltstone and the resulting saltstone properties. Regarding the Tc-99 solubility 

and Kd studies, the DOE staff indicated it expects to implement solubility limits for Tc-99 in 

future PA models and expects to have the peer-reviewed report supporting the chosen 

solubility limit values available in 2013. 

1.0 BACKGROUND: 

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

DOE, in consultation with 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. The 

NDAA also requires NRC to monitor DOE disposal actions related to those determinations to 

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

To carry out its monitoring responsibility under the NDAA, NRC, in coordination with the State 

site regulator – SC DHEC, performs three types of activities: (1) technical reviews, (2) onsite 

observation visits, and (3) data reviews. Those activities focus on key assumptions identified in 

the NRC monitoring plan. Technical reviews generally focus on reviewing additional model 

support for assumptions that DOE made in its PA that are considered important to the DOE 
compliance demonstration. Onsite observation visits generally are performed to: (1) observe 

the collection of data (e.g., observation of waste sampling used to generate radionuclide 

inventory data) and review the data to assess consistency with assumptions made in the waste 

determination; and (2) observe key disposal or closure activities related to technical review 

areas (e.g., slag/other material storage, grout formulation, preparation, or placements). Data 

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

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

compliance with the performance objectives. 

On March 31, 2005, DOE submitted to 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, NRC staff reviewed the draft waste 

determination. In the TER issued in December 2005 (NRC, 2005), 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, DOE issued the final waste determination in 

January 2006 (DOE-WD-2005-001, Rev. 1). 

DOE submitted a revised PA to NRC in 2009 (SRR-CWDA-2009-00017). NRC reviewed 

SRR-CWDA-2009-00017, including holding public meetings, sending requests for additional 

information, and reviewing the DOE responses. On April 30, 2012, NRC issued both the TER 

(NRC, 2012a) and the Type IV Letter of Concern (NRC, 2012b). In the 2012 TER, NRC 

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

performance objectives in 10 CFR Part 61, specifically §61.41. The Type IV Letter of Concern 

formally communicated the NRC concerns to both DOE and the SC DHEC. 

In July 2012, DOE responded to the Type IV Letter to NRC (DOE, 2012a; DOE, 2012b). DOE’s 

response included information about an updated technetium-99 (Tc-99) inventory projection for 

the newly constructed disposal structures; and information about the DOE Case K and K1 

uncertainty and sensitivity analyses. In response to DOE’s submittal, NRC issued a letter of 

acknowledgement, dated August 31, 2012, stating that a (Type II) Letter to the U.S. Congress is 

not needed at this time. Based on the NRC’s TER analyses and DOE’s revised Tc-99 

inventory, the staff determined that, if DOE’s new projected Tc-99 inventory for the newly 

constructed disposal structures is correct, then it is unlikely to cause an off-site peak dose 

exceeding the requirements of §61.41 (i.e., 0.25 mSv/yr (25 mrem/yr)). 

2.0 NRC ONSITE OBSERVATION VISIT ACTIVITIES: 

Observation 2012-02 began with a short briefing on the agenda and site safety procedures 

presented by DOE and attended by representatives from DOE, NRC, and SC DHEC. 

Discussions that followed included follow-up items from the August 2012 observation, details of 

the recent saltstone production run into Saltstone Disposal Structure (SDS) 2B, and research 

results from experiments conducted in accordance with DOE’s performance assessment 

maintenance program (as they relate to issues identified in NRC’s 2012 TER). This report 

summarizes those discussions. 
Prior to Observation 2012-02, DOE provided NRC staff with a group of documents covering 

research related to issues identified in NRC’s TER (NRC, 2012a). In addition, DOE also 

requested a public meeting for January 2013 to further discuss research and modeling related 

to the concerns identified in the NRC’s TER. The discussion of these documents was limited 

because the documents were only provided for review one week in advance of the observation. 

Thus, this report does not necessarily represent a complete NRC review of these documents. 

Further discussion of each of these documents is included in the January 17, 2013 public 

meeting agenda. 

At the start of the observation an additional topic was discussed that was not on the agenda. 

This was the introduction of a new term, “disposal structure”, that could be used to designate 

both DOE “vaults” and “future disposal cells” in future documents, such as the revised 

Monitoring Plan or observation guidance. A saltstone disposal structure is a self-enclosed 

engineered barrier that is designed to limit the release of saltstone to the environment. A 

disposal structure may include one or more cells. In this and future NRC documentation related 

to the SDF, the term “disposal structure” refers to DOE “Vault 1”, “Vault 4”, and “future disposal 

cells.” The term “disposal structure” could also be used to refer to potential new DOE designs 

for structures to contain saltstone. The DOE term “Saltstone Disposal Unit” typically denotes a 

set of disposal structures (e.g., Saltstone Disposal Unit 2 includes SDS 2A and 2B). 

2.1 Previous Observation Follow-up: 

2.1.1 Observation Scope:

Observation visits typically begin with a discussion of the status of action items from the 

previous visit. Thus, this portion of the observation report applies to items discussed in the 

previous onsite observation (NRC, 2012e). 

2.1.2 Observation Results:

DOE provided an update on each of the follow-up actions discussed during the August 2012 

observation. Each follow-up item is provided below. For more details, please review DOE’s 

presentation from the observation (SRR-CWDA-2012-00165). 

Completed Items from August Observation

2012-01-1. DOE to provide cure temperature profiles for field-emplaced saltstone 

(Explanation in SRNL-STI-2012-00558). 

2012-01-2. DOE to provide analytical documents referenced in Table 1 from 

SRR-CWDA-2012-00095 (SRNL-l3100-2012-00062, X-ESR-H-00377, and 

SRR-LWE-2012-00130). 

2012-01-3. DOE to clarify the interpretation of lysimeter concentration data as it relates to 

evaporation from the collection vessels (Explanation in 

SRR-CWDA-2012-00165). 
2012-01-4. DOE to clarify the interpretation of data related to water that flows around the 

lysimeter cementitious samples (Explanation in SRR-CWDA-2012-00165, but 

the NRC staff notes that the interpretation of data obtained from the 

lysimeters is a challenging problem due to uncertainty in the flow of the water 

around the saltstone simulant). 

2012-01-5. NRC Action: NRC to provide informal integrated priority list of monitoring 

factors to DOE. 

2012-01-6. DOE to provide a document list4

. 

2012-01-7. DOE to provide SRR-CWDA-2012-00112. 

2012-01-8. DOE to provide SDS 3A leachate collection construction details. 

2012-01-9. DOE to provide the distance of the groundwater monitoring wells from SDSs 

2A and 2B. 

2012-01-10. DOE to define which aquifers the wells near SDSs 2A and 2B are screened 

in. 

2012-01-11. DOE to provide information related to Tc-99 concentrations beyond Batch 7 

and anticipated through 2015 (DOE will provide this when data becomes 

available). During observation 2012-02, this action was rewritten as two 

new follow-up actions (see later list). 

Items from August Observation to be Revisited

2012-02-1. DOE to provide an estimate of the volume of water from environmental 

sources, if any, intruding into SDS 4 (Expected completion 

February 15, 2013). 

2012-02-2. DOE to describe the expected surveillance and maintenance program for 

disposal structure penetrations after operations and prior to final site closure 

(Expected completion Fall 2013). 

2012-02-3. DOE to describe the plans to maintain or close the drain water removal 

system after operations and prior to final closure (e.g., maintenance of 

instrumentation for liquid detection) (Expected completion Fall 2013). 

 

4

 Based on the experience both agencies have gained under NDAA monitoring, both NRC and DOE 

agreed that the updated monitoring plan will include a list of certain original and updated documents DOE 

will provide to NRC that are relevant to the NRC in performing its NDAA monitoring responsibilities. This 

“Document List” will be included in the appendix of the updated NRC monitoring plan. 
New Items from August Observation Follow-up Discussion

2012-02-4. New Follow-up Action: Discuss, as needed, the Salt Macro-batch 6 

qualification sample report and any additional sampling reports related to Salt 

Batch 7 at January public meeting. 

2012-02-5. New Follow-up Action: Add Salt Batch qualification sample reports on the 

routine document list in the revised NRC monitoring plan. 

2.1.3 Conclusions and Follow-up Actions:

The NRC staff will continue to monitor the progress of the Items from August Observation to be 

Revisited list of follow-up actions from the August 2012 observation. Five follow-up actions 

resulted from this site observation visit (visit 2012-02). The list is composed of the three items 

in the Items from August Observation to be Revisited list and two new actions born of the 

discussion regarding Tc-99 concentrations beyond Batch 7. 

2012-02-1. DOE to provide an estimate of the volume of water from environmental 

sources, if any, intruding into SDS 4 (Expected completion 

February 15, 2013). 

2012-02-2. DOE to describe the expected surveillance and maintenance program for 

disposal structure penetrations after operations and prior to final site closure 

(Expected completion Fall 2013). 

2012-02-3. DOE to describe the plans to maintain or close the drain water removal 

system after operations and prior to final closure (e.g., maintenance of 

instrumentation for liquid detection) (Expected completion Fall 2013). 

2012-02-4. NRC and DOE to discuss, as needed, the Salt Macro-batch 6 qualification 

sample report and any additional sampling reports related to Salt Batch 7 at 

January 2013 public meeting. 

2012-02-5. NRC and DOE to add Salt Batch qualification sample reports on the routine 

document list in the revised NRC monitoring plan. 

2.2 Technical Discussion – Salt Waste Processing: 

2.2.1 Observation Scope:

NRC staff monitors salt waste processing, including qualification of salt batches. Salt waste 

processing and quality assurance are critical to grout quality. A discussion of grout quality 

includes the qualification of salt batches and grout production at SPF. Batch qualification 

ensures that the feed material is within tolerances acceptable to production, and production 

variables such as water to premix ration, dry feeds variability, and curing conditions, impact the 

performance of the waste form. Worker doses during salt waste grout processing and SDS 

operation are directly related to the performance objective for protection of individuals during 

operations (i.e., §61.43). Section 3.2.2, “Waste Sampling”, Section 3.2.3, “Vault Construction”5

, 

Section 3.2.4, “Grout Formulation and Placement”, and Section 5, “Monitoring to Assess 

 

5 “Vault” is a historical DOE term for a type of disposal structure. 
Compliance with §61.43 – Protection During Operations” of the May 2007 monitoring plan 

(NRC, 2007a) provide details of the basis for NRC staff review areas. 

2.2.2 Observation Results:

DOE provided an update of salt waste grout processing, including details of recent saltstone 

processing in SDS 2B. Approximately 4.2 million liters (1.1 million gallons) of salt waste was 

disposed into SDS 2B from Tank 50 in September and October of 2012. DOE stated that the 

SPF had operated for 19 days in October, completely processing all of the available feed in the 

SPF feed Tank (Tank 50). The following bullets provide a highlight of the discussion: 

• DOE noted it planned to process more saltstone at the SPF in March 2013, but that this 

date may slip depending on the resolution of an operational issue at the Defense Waste 

Processing Facility. 

• DOE stated there had been a seep through an electrical conduit on SDS 4 and that 

contamination was found on the exterior disposal structure wall. DOE noted that these 

types of conduits through the disposal structure walls will be sealed prior to site closure. 

• DOE described improved technology for monitoring dry feeds batch data and showed 

data for approximately 2,700 batches that indicated limited variability in slag, fly ash, and 

cement values. 

• DOE showed video of saltstone being poured into SDS 2B and a video survey of the 

inside of SDS 2B after saltstone had cured for approximately 3 days. The video showed 

condensation on the ceiling of the disposal structure, which indicated that saltstone was 

curing in a humid environment. DOE noted it would continue video surveys of the inside 

of SDS 2B and would continue to look for signs of condensation. DOE noted disposal 

had not yet begun in SDS 2A. 

• DOE indicated that the elevation of the top surface of saltstone varied by approximately 

3 inches across SDS 2B. 

• DOE noted an upward trend in cesium content in the Z-area storm water runoff basin, 

which would be documented in the 2012 SRS annual environmental report. The NRC 

staff will continue to monitor radionuclide concentrations in the Z-area storm water runoff 

basin and evaluate implications for site performance. 

Details, including plots on daily disposal operations can be found in DOE’s presentation 

(SRR-CWDA-2012-00165). 

2.2.3 Conclusions and Follow-up Actions:

The NRC staff will continue to monitor SPF activities, including any changes in the SPF 

production schedule, as the SPF exits its current outage and DOE transfers saltstone grout to 

SDSs 2A, 3A, 3B, 5A, and 5B (i.e., all of the newly constructed disposal structures except 2B). 

There were no follow-up actions that resulted from this technical discussion. 
2.3 Technical Discussion – Performance Assessment Maintenance Research Activities

2.3.1 Observation Scope:

DOE uses its performance assessment maintenance program to both satisfy DOE internal 

requirements and address technical topics in the NRC monitoring plan. As part of monitoring 

under the NDAA, NRC is responsible for reviewing updates to the DOE performance 

assessment. Section 3.1.2 “Oxidation of Saltstone,” Section 3.1.3, “Hydraulic Isolation of 

Saltstone,” and Section 3.1.4, “Model Support” of the May 2007 monitoring plan (NRC, 2007a) 

provide details of the basis for the NRC staff review areas. 

2.3.2 Observation Results:

DOE Manual 435.1-1 (DOE, 2001a) requires DOE to implement a PA maintenance program to 

evaluate changes that could affect the performance, design, and operating bases for the SDF. 

DOE Order 435.1 (DOE, 2001b) states that the PA maintenance program must include the 

conduct of research, field studies, and monitoring needed to address uncertainties or gaps in 

existing data. In addition to fulfilling those internal DOE requirements, DOE uses PA 

maintenance activities to address technical topics in the NRC monitoring plan. 

Prior to Observation 2012-02, DOE provided NRC staff with a group of documents covering 

research related to issues identified in NRC’s TER (NRC, 2012a). In addition, DOE also 

requested a public meeting for January 2013 to further discuss research and modeling related 

to the concerns identified in the NRC’s TER. The discussion of these documents was limited 

because the documents were only provided for review one week in advance of the observation. 

Thus, this report does not represent a complete NRC review of these documents. As 

necessary, further discussion of some of these documents may take place during the 

January 17, 2013 public meeting. 

The bulleted list below provides a brief summary of NRC’s assessment following a limited 

review of each document and discussion with DOE during the observation. Follow-up actions 

resulting from discussion are bolded. 

Operating Window Property Testing (SRNL-STI-2012-00558)

• It is unclear to NRC staff why the results in SRNL-STI-2010-00745 are not applicable to 

emplaced saltstone. In this study, the researchers appear to have appropriately 

controlled for water loss from the saltstone samples, so it does not appear that the high 

hydraulic conductivity values are due to the sample drying and cracking. NRC staff also 

noted that the correlation of the scanning electron micrograph results with the hydraulic 

conductivity measurements made the study results more persuasive. DOE staff 

suggested that in SRNL-STI-2010-00745 sample temperature had increased more 

rapidly than the emplaced saltstone temperature would increase during curing. 

• DOE presented results (SRNL-STI-2012-00558; Table 3-6) showing little effect of liquid 

to premix ratio from approximately 0.59 to 0.64. NRC staff noted that beyond that range, 

the effect seemed greater (SRNL-STI-2012-00558; Table 3-6), and that the 

instantaneous liquid to premix ratios during system flushes (SRNL-STI-2012-00558; 

page A-2) was much greater than the tested range. The NRC staff expressed interest in 

understanding the volume of grout affected by the flush water. NRC and DOE discussed 
the need to understand how much mixing occurs when the additional flush water is 

added to the system and how much of this water is captured by the sheet drain. NRC 

staff is concerned that this extra water may result in a high water to premix ratio that has 

not been evaluated in laboratory samples. 

• During the meeting, NRC was shown graphs of thermocouple data from the curing of 

saltstone in SDSs 2B and 4. DOE provided an explanation of the constraints and 

availability of those data. Because of the amount of thermocouple data that DOE 

has collected, DOE requested that NRC provide specific temporal and spatial 

details of the data to be supplied. NRC agreed to provide specific details in its 

request shortly after the observation. 

Tc-99 Solubility and Kd Studies (PNNL-21723 and SRNL-STI-2012-00596)

• DOE and NRC staff discussed one of the main conclusions of these research reports, 

which is that Tc release under reduced conditions should be modeled as solubilitycontrolled instead of with a Kd model. DOE stated that it is preparing a report that will 

summarize relevant studies related to Tc-99 release from saltstone and provide a basis 

for values to be used in a PA. DOE expects this report to be complete in January 2013. 

DOE also indicated that this report would undergo independent peer review. 

• DOE staff suggested that an observed decrease in aqueous Tc-99 concentrations with 

time in laboratory samples (PNNL-21723; Figure 3.1) may be indicative of continued 

reaction with slag immobilizing Tc. The NRC staff noted that, after 14 days of reaction, 

the slope of the decrease in the Tc-99 concentrations with time in the non-slag control 

was similar to the decrease with time in the slag-containing samples. In addition, the 

concentrations of several species (e.g., K, Na), listed in the appendix, also show similar 

decreases in concentration after 14 days. Although the authors of the report addressed 

the changing Tc concentrations in terms of changing solution chemistry, NRC staff 

expressed interest in understanding whether the rate of decrease of the concentrations 

could be due to other mechanisms that could affect several species (e.g., dilution 

introduced by replacing sampled solution). 

• NRC staff appreciates the difficulty in determining solubility values for a laboratory 

system that is (1) not at equilibrium, (2) sensitive to the changing chemical conditions, 

(3) not well characterized in the literature due to its unique chemical composition. 

Depending on the approach (i.e., solubility or sorption-controlled release of Tc-99) and 

values that DOE implements in their revised model, additional information may be 

requested in the future to better understand the results from this study. 

• DOE stated the Kd values presented in SRNL-STI-2010-00668, Revision 0 were 

incorrect. The revised calculations will be included in Revision 1 of that document and 

the final values are included in SRNL-STI-2012-00596. NRC requested receipt of 

SRNL-STI-2010-00668, Revision 1 when it becomes available. 

• NRC staff noted that the long equilibration time for precipitation of Tc-99 under reducing 

conditions and the rapid release of Tc under oxidizing conditions may indicate limited 

retention capability of the disposal structure concrete for Tc-99 in fast pathways. 
Method Evaluation for Measuring Oxidation Front Movement (SRNL-STI-2012-00468, Rev. 0)

• NRC stated that this research, which evaluated several methods for determining the rate 

of oxidation front movement in saltstone, appeared to be well designed and could 

provide important insights. 

• NRC asked if this research report would be used to evaluate the rate of oxidation front 

movement that was assumed in the 2009 PA (SRR-CWDA-2009-00017). DOE stated 

that the samples in this study may have been compromised due to experimental artifacts 

and that this research focused on method evaluation. 

• DOE discussed its strategy of creating one large batch of samples that could serve as 

the basis for multiple studies. NRC staff noted that the oxidation front study relied on 

Chromium- (Cr-spiked) samples and discussed the importance of having some nonCr-spiked control samples so that it would be clear if any unexpected results were 

attributable to the Cr spike. 

Fracture Transport (SRNL-STI-2012-00267)

• DOE described its approach of focusing on gas and liquid transport in fractures and then 

modeling the effects of different potential fractured saltstone states. NRC staff indicated 

it understood this approach. In response to NRC questions, DOE indicated it did not 

currently have a plan to develop additional support for predictions of saltstone fracturing 

for thousands of years after closure. 

• DOE also stated that instead of attempting to design experimental studies to evaluate 

flow through fractures, due to the complexity of fracture networks (e.g., fracture aperture, 

spacing, orientation, connectedness), they would evaluate the effects of various 

modeled fracture networks on flow through saltstone. 

Formed Core Sampling (SRNL-STI-2012-00551)

• DOE and NRC staff discussed the status of the development of the formed core 

sampling technique. The density and porosity of formed-core samples and core-drilled 

samples were comparable; however, the hydraulic conductivity measurements of the 

samples were not consistent, because of pouring sequence and curing conditions. DOE 

stated that the technique was not yet ready for deployment in the full-scale disposal 

structures. 

Review of Concrete Biodeterioration (SRNL-STI-2012-00435)

• DOE discussed that saltstone grout is not expected to be impacted by microbial activity 

due to the high pH and osmotic pressures associated with the waste form. DOE also 

stated that biodegradation of the disposal structures is a possibility, but that there is 

limited organic material in the soils due to the depositional history of SRS. 

• NRC staff noted the report conclusions which state that the disposal structures will be 

impacted to some degree by microbial activity, depending on the site-specific conditions. 

NRC staff also noted that DOE’s disposal activities will alter the current environment and 

potentially provide energy sources for microorganisms. 
Comparison of Wasteform Mixtures (SIMCO, 2012)

• DOE discussed that the current formulation of 45% blast furnace slag: 45% fly ash: 10% 

cement had superior pore structure and transport properties relative to a previous 

formulation. 

• DOE stated that there are no immediate impacts on PA from this review. 

Following discussion of the technical reports, DOE stated that they would be providing 

additional documentation in preparation for the January 2013 public meeting. DOE stated that 

they would be providing the modeling inputs change matrix from the FY13 Special 

Analysis to NRC shortly after the observation. 

2.3.3 Conclusions and Follow-up Actions

Three follow-up actions resulted from these discussions: 

2012-02-6. DOE to provide additional thermocouple data for SDSs 2B and 4, including 

an elevation measurement and a plan view of the location of the 

thermocouples corresponding to each data series. NRC will provide 

additional specifications for its request shortly after the observation. 

2012-02-7. DOE to provide revision 1 of SRNL-STI-2010-00668 when it becomes 

available. 

2012-02-8. DOE to provide the FY13 Special Analysis modeling inputs change matrix to 

NRC shortly after the observation. 

3.0 FOLLOW-UP ACTIONS AND OVERALL CONCLUSIONS

3.1 Follow-up Actions from the Technical Discussion – Previous Observation Follow-up

2012-02-1. DOE to provide an estimate of the volume of water from environmental 

sources, if any, intruding into SDS 4 (Expected completion 

February 15, 2013). 

2012-02-2. DOE to describe the expected surveillance and maintenance program for 

disposal structure penetrations after operations and prior to final site 

closure (Expected completion Fall 2013). 

2012-02-3. DOE to describe the plans to maintain or close the drain water removal 

system after operations and prior to final closure (e.g., maintenance of 

instrumentation for liquid detection) (Expected completion Fall 2013). 

2012-02-4. (new) As needed, NRC and DOE to discuss Salt Macro-batch 6 

qualification sample report and any additional sampling reports related to 

Salt Batch 7 at the January public meeting. 

2012-02-5. (new) NRC and DOE to add Salt Batch qualification sample reports to the 

routine document list in the revised NRC monitoring plan. 
3.2 Follow-up Actions from the Technical Discussion – Salt Waste Processing

None 

3.3 Follow-up Action from the Technical Discussion – Performance Assessment 

Maintenance Research Activities

2012-02-6. DOE to provide additional thermocouple data for SDS s 2B and 4, 

including an elevation measurement and a plan view of the location of the 

thermocouples corresponding to each data series. NRC will provide 

additional specifications for its request shortly after the observation. 

2012-02-7. DOE to provide revision 1 of SRNL-STI-2010-00668 when it becomes 

available. 

2012-02-8. DOE to provide the FY13 Special Analysis modeling inputs change matrix 

to NRC shortly after the observation. 

3.4 Overall Conclusions

There are no new Open Issues resulting from Observation 2012-02. The previous Open Issues 

are now rolled into the concerns identified by NRC in the 2012 TER (NRC, 2012a). Those NRC 

concerns will be rolled into the monitoring factors in the revised monitoring plan that is being 

drafted by NRC. Based on the results of Observation 2012-02, there is no change to the NRC 

conclusions in that TER – NRC continues to conclude that it does not have reasonable 

assurance that salt waste disposal at the SDF meets the performance objectives in 

10 CFR Part 61, specifically §61.41. 

4.0 PARTICIPANTS

U.S. NRC SC DHEC US. DOE SRR

George Alexander 

Nishka Devaser 

Christepher McKenney 

Karen Pinkston 

A. Christianne Ridge 

Gregory O’Quinn Sherri Ross 

Patricia Suggs 

Linda Suttora 

Armanda Watson 

Bill Barnes 

Kim Hauer 

Keith Liner 

Kent Rosenberger 

Mark Schmitz 

F. Malcolm Smith 

Aaron Staub 

Steve Thomas 

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