DOCKET NO: A-98-49; II-A4-182

WASTE CHARACTERIZATION REPORT

TIER 1 CHANGE EVALUATION:

CHANGING CALIBRATION TO INCLUDE A FIVE-FOOT DETECTOR SETBACK

CONFIGURATION ON THE NONDESTRUCTIVE ASSAY BOX COUNTER TO ASSAY 

STANDARD LARGE BOXES TYPE 2 FOR THE CENTRAL CHARACTERIZATION 

PROJECT AT THE SAVANNAH RIVER SITE

U.S. Environmental Protection Agency

Office of Radiation and Indoor Air

Center for Waste Management and Regulations

1200 Pennsylvania Avenue, NW

Washington, DC 20460

March 2014
i

TABLE OF CONTENTS

Section Page

Abbreviations and Acronyms ......................................................................................................... ii

1.0 Introduction..........................................................................................................................4

2.0 Purpose of Tier 1 Evaluation ...............................................................................................5

3.0 Purpose of This Report ........................................................................................................5

4.0 Scope of Review ..................................................................................................................6

5.0 Tier 1 Evaluation Personnel.................................................................................................6

6.0 Technical Evaluation of Nondestructive Assay...................................................................6

6.1 System Description ..................................................................................................6

6.2 Spectral Interpretation..............................................................................................8

6.3 Technical Basis for Change .....................................................................................8

6.4 Documents Reviewed ..............................................................................................9

6.5 Evaluation Checklist ................................................................................................9

6.6 Gamma Calibration, Calibration Validation and Confirmation...............................9

6.7 Changes to Gamma Operating Range....................................................................10

6.8 Specific Limits on Assay Conditions for the Five-Foot Setback...........................10

6.9 Lower Limit of Detection Determination ..............................................................10

6.10 Total Measurement Uncertainty ............................................................................10

7.0 Findings and Concerns.......................................................................................................10

8.0 Conclusions........................................................................................................................11

LIST OF TABLES

Table 1. Evaluation Personnel ........................................................................................................ 6

ATTACHMENTS

Attachment A Approval Summary for SRS-CCP Contact-Handled Waste Characterization 

Program

Attachment B Nondestructive Assay Box Counter Evaluation Checklist – Far-Field 

Geometry for Standard Large Boxes Type 2 Geometry
ii

ABBREVIATIONS AND ACRONYMS

AK acceptable knowledge

Am americium

BDR batch data report

BNAS Box Neutron Assay System 

BSGS Box Segmented Gamma System

CBFO Carlsbad Field Office

CCP Central Characterization Program

Cd cadmium

CFR Code of Federal Regulations

CH contact-handled

Cm curium 

Co cobalt 

Cs cesium 

Cu copper

DOE U.S. Department of Energy

EA Expert Analyst

EPA U.S. Environmental Protection Agency

FFG far-field geometry

FRAM Fixed Energy, Response Function Analysis with Multiple Efficiency 

g gram

HS heat source

HPGe high-purity germanium

ISOCS In Situ Object Counting System

LLD Lower Limit of Detection

mCi millicuries

MGA multi-group analysis 

mm millimeter

NABC Nondestructive Assay Box Counter

NaI sodium iodide

nCi/g nanocuries per gram 

NDA nondestructive assay 
iii

Np neptunium

Pu plutonium

SLB2 Standard Large Box Type 2

Sr strontium

SRS Savannah River Site 

SWB Standard Waste Box 

T1 Tier 1

T2 Tier 2

TMU total measurement uncertainty

TRU transuranic

TRUPACT Transuranic Package Transporter

U uranium

WG weapons grade

WIPP Waste Isolation Pilot Plant
4

1.0 INTRODUCTION

This report supports the U.S. Environmental Protection Agency’s (EPA’s) approval of a Tier 1 

(T1) change to add a five-foot setback configuration to the Nondestructive Assay Box Counter 

(NABC) to assay Standard Large Boxes Type 2 (SLB2s) at the Savannah River Site (SRS). In 

accordance with Title 40 of the Code of Federal Regulations (40 CFR) 194.8(b), EPA conducted 

a baseline inspection of the Central Characterization Program (CCP)1 waste characterization 

program for contact-handled (CH) transuranic (TRU) wastes at the U.S. Department of Energy’s

(DOE’s) SRS in Aiken, South Carolina, in 2005. As a result, in July 2006, EPA approved the 

SRS-CCP CH TRU waste characterization program (see EPA Docket No. A-98-49, II-A4-65). 

On March 9, 2009, the Carlsbad Field Office (CBFO) requested EPA approval of a T1 change to 

add the NABC as a new nondestructive assay (NDA) system at SRS. EPA inspected and 

approved the NABC in 2009 (see EPA Docket No. A-98-49; II-A4-114). Following this

approval, CBFO requested and EPA granted approval of a T1 change to extend the calibration 

range of the gamma component of the NABC. On May 12, 2011, CBFO requested to change the 

calibration of the gamma component of the NABC to an efficiency-based calibration using the 

technical guidance of American Society for Testing and Materials Standard C113/C1133-10, 

which EPA approved. On July 3, 2012, CBFO requested approval of the five-foot setback 

configuration2for the NABC for assaying 55-gallon drums, which EPA inspected at SRS in July 

2012 and approved on September 11, 2012. On December 18, 2012, DOE requested to add a 

five-foot setback configuration to the NABC’s gamma component for assaying Standard Waste 

Boxes (SWBs). EPA approved this addition on February 21, 2013. EPA’s reviews and approvals 

of SRS-CCP’s CH waste characterization program are listed in Attachment A.

On January 8, 2014, DOE requested a T1 change to add the five-foot setback configuration to the 

NABC’s gamma component for assaying SLB2s, equivalent to what EPA approved previously 

for 55-gallon drums and SWBs as mentioned above. The five-foot setback configuration would 

allow the NABC to assay SLB2s that previously could not be assayed in the near-field 

configuration due to radionuclide interferences. This change applies only to the gamma 

component; the NABC neutron component is unchanged.

EPA evaluated the proposed T1 change by reviewing SRS-CCP documents. As a result of this 

evaluation, EPA determined that the five-foot setback configuration is technically adequate for 

assaying SLB2s. However, the five-foot setback configuration for assaying SLB2s is not 

approved at this time to discriminate TRU and non-TRU wastes in accordance with the 100 

nanocuries per gram (nCi/g) criterion, based on the technical documentation SRS-CCP provided.

EPA did not make any changes to the SRS-CCP RH T1 and Tier 2 (T2) designations that were 

established during the baseline approval and modified during subsequent T1 evaluations. The 

tiering designations presented in Table 1 of the final report for EPA’s approval of the five-foot 

 

1 The Central Characterization Program was formerly known as the Central Characterization Project, and 

both names are used in the documentation reviewed for this evaluation.

2 The initial configuration of the NABC is referred to as the “near-field” geometry or setting. The “five-foot

setback” is also referred to as “five-foot standoff” and “far-field geometry” or FFG, depending on the specific

application. SRS-CCP documents use all these terms.
5

setback configuration for the NABC for assaying SWBs (see EPA Docket No. A-98-49; 

II-A4-171; February 21, 2013) remain in effect.

2.0 PURPOSE OF TIER 1 EVALUATION

Any changes to the waste characterization activities from the date of the baseline inspection must 

be reported to and, if applicable, approved by EPA according to the tiering requirements set forth 

in the SRS baseline final report cited above.

Under the changes to 40 CFR 194.8 promulgated in the July 16, 2004, Federal Register notice, 

EPA must perform a single baseline inspection of a TRU waste generator site’s waste 

characterization program. The purpose of the baseline inspection is to approve the site’s waste 

characterization program based on the demonstration that the program’s components, with 

applicable conditions and limitations, can adequately characterize TRU wastes and comply with 

the regulatory requirements imposed on TRU wastes destined for disposal at the Waste Isolation 

Pilot Plant (WIPP). An EPA inspection team conducts an onsite inspection to verify that the 

site’s system of controls is technically adequate and properly implemented.

Following EPA’s approval of waste characterization processes evaluated during the baseline 

inspection, EPA is authorized to evaluate and approve, if necessary, changes to the site’s 

approved waste characterization program by conducting additional inspections under the 

authority of 40 CFR 194.24(h). Under 40 CFR 194.24, EPA has the authority to conduct 

continued compliance inspections to verify that the site continues to use only the approved waste 

characterization processes to characterize the waste and remains in compliance with all of the

regulatory requirements. Based on the adequacies of the waste characterization processes 

demonstrated during the baseline inspection, including all conditions and limitations, EPA 

specified which subsequent waste characterization program changes or modifications must 

undergo further EPA inspection or approval under 40 CFR 194.24. This was accomplished by 

assigning a tier level to each aspect of the SRS-CCP characterization program. T1 activities have 

more stringent reporting requirements and require that DOE notify EPA and that EPA provide 

approval prior to implementation. The rule under which baseline inspections are conducted can 

be found in the Federal Register (Vol. 69, No. 136, pages 42571–42583) of July 16, 2004.

3.0 PURPOSE OF THIS REPORT

This report presents the results of EPA’s evaluation of a T1 change to allow the use of the NABC

in a five-foot setback configuration for gamma assays of SLB2s. This report documents the basis 

for EPA’s approval decision and explains the results of the technical evaluation of the system, 

including any limitations. EPA’s approval decision regarding the new measurement 

configuration of the NABC has been conveyed to DOE separately by letter. EPA will also 

announce the decision on its website at www.epa.gov/radiation/wipp, in accordance with

40 CFR 194.8(b)(3).

The documents that EPA reviewed for this evaluation that are cited in this report can be 

requested from:
6

Carlsbad Field Office

Manager, National TRU Program

U.S. Department of Energy

P.O. Box 3090

Carlsbad NM 88221-3090

4.0 SCOPE OF REVIEW

The scope of this review is to evaluate a new measurement configuration to an approved SRSCCP NDA system. The NABC high-purity germanium (HPGe) detectors were physically moved 

five feet further away from the SLB2 being assayed. This change pertains only to the gamma 

component of the NABC, and does not affect any other aspects of the instrument previously 

approved, as described below. EPA evaluated this proposed change request in accordance with 

40 CFR 194.8(b) to assess the extent and effects of this change on the NABC and the assays 

produced from the new configuration, as discussed in this report.

5.0 TIER 1 EVALUATION PERSONNEL

Table 1 lists all EPA personnel involved in this T1 evaluation, along with their professional 

affiliations and T1 evaluation functions. EPA relied primarily on reviews of documents and 

information provided by SRS-CCP. When additional information or clarifications were needed, 

EPA made these requests via email and SRS-CCP provided the needed information 

electronically.

Table 1. Evaluation Personnel

6.0 TECHNICAL EVALUATION OF NONDESTRUCTIVE ASSAY

6.1 System Description

SRS-CCP operates the NABC that is located at SRS, E Area, Building 643-43E; it has not been 

moved since EPA approved it initially in 2009. Although SRS-CCP documentation refers to it as 

a single system, the NABC is in fact two distinct NDA systems: a neutron system, referred to as 

the Box Neutron Assay System (BNAS), which produces neutron data that are transformed into 

quantitative values upon application of isotopic (mass fraction) values; and the Box Segmented 

Gamma System (BSGS), which supplies isotopic values for use with the BNAS neutron data or 

provides stand-alone quantitative gamma-based values. The BNAS design and operation are 

unchanged and these aspects are not addressed in this report. Previous EPA reports (Docket Nos. 

A-98-49; II-A4-114 and A-98-49; II-A4-133) describe the NABC system in detail. Typically, a 

container is assayed on both the BNAS and the BSGS, following which there are three analytical 

options:

Personnel Name Affiliation T1 Evaluation Function

Ed Feltcorn EPA EPA Lead Inspector

Patrick Kelly SC&A/EPA EPA Technical Evaluator

Rose Gogliotti SC&A/EPA EPA Technical Evaluator
7

 BNAS data are converted to radionuclide-specific values using the isotopic results 

provided by the BSGS.

 BNAS data are converted to radionuclide-specific values using isotopic results based on 

SRS-CCP acceptable knowledge (AK).

 BSGS data provide quantitative radionuclide values directly without relying on any 

BNAS values.

SRS-CCP subjects every NABC assay to review by an Expert Analyst (EA), who determines 

which analytical options are appropriate for a specific assay. The EA evaluates the attributes and 

appropriateness of the gamma and neutron assays based on: spectral quality; the presence of 

specific neutron interferences, e.g., curium-244 or elevated concentrations of americium-241 

(

241Am), uranium-235 (235U), plutonium-238 (238Pu) or neptunium-237 (237Np); agreement 

between gamma and neutron values; radionuclides expected based on AK; and other technical 

aspects. The EA may use a neutron NABC value with a near-field or far-field gamma value or an 

AK-derived isotopic value, or the EA may use the near-field or far-field quantitative gamma 

value by itself as the assay of record. The EA’s choice of assay mode(s) and other comments for 

each container are documented on an automated independent technical review sheet that is 

included in the NABC batch data report (BDR).

EPA previously approved the NABC for the near-field geometry for use with 55-gallon drums, 

SWBs, and SLB2s and the far-field geometry for use with 55-gallon drums and SWBs. The 

BSGS far-field geometry assays were confirmed for the efficiency-based nonattenuated mode.

3

SRS-CCP requested approval of this change to also assay SLB2s in the far-field geometry, which 

required an additional calibration for the BSGS. 

During a previous onsite evaluation, EPA observed operation of the NABC in the five-foot 

setback configuration for 55-gallon drums. The operational procedure (CCP-TP-189, Revision 

2)4had not been revised to accommodate the five-foot setback configuration for the previouslyapproved containers because the procedure adequately addressed changing measurement 

configurations of the NABC to allow for assaying 55-gallon drums, SWBs and SLB2s. Similarly, 

the procedures for calibration (CCP-TP-190, Revision 2)5and data review (CCP-TP-193, 

Revision 3)6 were not changed in response to the five-foot setback configuration for the previous 

containers and the same was true for SLB2s. 

The NABC integrates the BSGS and BNAS detection modes, both of which are described in 

previous EPA evaluations. 

 

3 The combination mass-based/efficiency-based mode was not confirmed for the five-foot setback for any 

size waste container.

4 Central Characterization Project, CCP Box Segmented Gamma System (BSGS) Operating Procedure, 

CCP-TP-189, Revision 2, May 4, 2011.

5 Central Characterization Project, CCP Box Segmented Gamma System (BSGS) Calibration Procedure, 

CCP-TP-190, Revision 2, May 5, 2011.

6 Central Characterization Project, CCP Data Reviewing, Validating, and Reporting Procedure for the 

Nondestructive Assay Box Counters, CCP-TP-193, Revision 3, August 8, 2011.
8

6.2 Spectral Interpretation

The gamma spectra for SLB2s assayed with the five-foot setback configuration are typically 

more complex than near-field spectra. Because of the interferences discussed in section 6.3

below, these spectra often require interpretation for which the experience of the EA is 

fundamentally important. The EA has considerable latitude in approving NABC assays. The 

assay data from the proposed configuration for the two SLB2s were evaluated by one EA, Daniel 

Remington. EPA interviewed Mr. Remington during the original far-field 55-gallon drum T1

approval and found him to be well qualified to evaluate challenging NABC spectra. EPA did not 

interview Mr. Remington nor review his training records as part of this activity. EPA will assess 

Mr. Remington’s training at the next EPA’s Continued Compliance inspection later this year.

6.3 Technical Basis for Change

SRS-CCP has a population of SLB2s that cannot be assayed using the near-field configuration 

due to high concentrations of cesium-137 (137Cs), 241Am or 238Pu. Such containers pose two basic 

problems for near-field assays:

 High concentrations of these radionuclides produce photons that flood the detector. The 

detector has a minimum amount of time that must separate two photons in order for them 

to be seen as separate events. Any new photon that strikes the detector while it is still 

processing the initial photon is not counted. This minimum time separation is referred to 

as the “dead time” of the counting system, i.e., the time during which the detector cannot 

record a new photon because it is busy recording a previous photon. The number of 

photons that are not counted (called “dead-time losses”) can be considerable with highcontent waste containers. Some SRS-CCP containers have dead-time losses greater than 

80% in the near-field configuration, making the containers impossible to assay in this 

configuration.

 Elevated concentrations of 137Cs, 241Am or 238Pu produce spectral interferences due to 

their gamma emissions at higher energy. These obscure 239Pu and other WIPP-tracked 

radionuclides that have lower energy emissions and render the spectra unusable.

Increasing the detector distance from these containers can solve both problems. The distance of 

five feet was chosen because it is the maximum detector-to-container-distance possible with the 

detectors remaining inside the physical NABC enclosure. The increased detector-to-container 

distance, however, reduces the number of photons reaching the detector and requires an 

increased counting time (i.e., 60-minutes versus the standard 20-minutes count time) but reduces 

the interferences described above and therefore, can allow problematic containers to be assayed 

successfully. 

SRS-CCP has successfully assayed drums and SWBs with the far-field configuration that were 

not possible to assay with the near-field geometry. Similarly, SRS-CCP presented assay data 

from two SLB2s with dead time losses as high as 80% on previous assays using the near-field 

geometry. The addition of SLB2s to the far-field geometry allowed SRS-CCP to successfully 

assay these SLB2s, as documented in the NABC BDR (BDR # SRLBC0994).
9

6.4 Documents Reviewed

EPA evaluated the following documents to support the approval of the addition of a five-foot 

geometry of the BSGS:

 CCP-SRS-SRBC001, “Nondestructive Assay Box Counter, Calibration Validation and 

Confirmation Report for Gamma Modality,” Revision 7, July 15, 2013.

 CCP-SRS-SRBC002, “Nondestructive Assay Box Counter, Calibration Validation and 

Confirmation Report for the Neutron Modality,” Revision 1, June 4, 2009.

 SLB2 ISOCS Calibration of the Savannah River Box Counter: 5ft Set Back Calibration, 

Paul LeBlanc, IV, Canberra Industries, Inc., June 24, 2013 (included as Appendix Q-3 in 

CCP-SRS-SRBC001).

 NABC BDR No. SRLBC0994.

 Savannah River Gamma Box Counter Calibration Report Alternatives for NonDestructive Assay (NDA) of Large Containers to Allow Shipping in TRUPACT III 

without Resizing and/or Repackaging, Canberra Document No. 40945, July 2004.

 Response to EPA Regarding Savannah River Site Tier 1, 5-foot Setback for 2 SLB2s 

Large Box Gamma Counter, Memorandum from Site Docs in response to EPA inquiry, 

February 27, 2014.

6.5 Evaluation Checklist

Based on EPA’s review of the SRS-CCP documents listed above, EPA prepared a revised 

checklist for this evaluation that addressed the relevant aspects of the proposed change to the 

measurement configuration. The bulk of the evaluation is documented in the checklist, which is 

included as Attachment B to this report.

6.6 Gamma Calibration, Calibration Validation and Confirmation

The NABC’s HPGe gamma detectors were initially characterized by the In Situ Object Counting 

System (ISOCS) for the five-foot setback configuration at Canberra’s facility in Meriden, 

Connecticut, as documented in the Canberra calibration document. This configuration was 

validated at SRS using mixed-gamma-line sources 241Am, barium-133, 137Cs and cobalt-60 for 

the multi-density efficiency-based summed spectrum mode for a combination cardboardplywood matrix. The sources were the same as those used in the initial factory calibration, and 

the measurements met all acceptance criteria, as documented in CCP-SRS-SRBC001.

The calibration confirmation measurements were performed for one high mass weapons grade 

(WG) Pu loading and one high mass heat source (HS) Pu loading in an SLB2. Copies of the 

source certifications are in CCP-SRS-SRBC001, Appendices C-1 and C-2. The confirmation 

measurements met the WIPP Waste Acceptance Criteria7requirements for precision and 

accuracy and the results of these measurements are provided in CCP-SRS-SRBC001, Appendix 

 

7 U.S. DOE CBFO, “Transuranic Waste Acceptance Criteria for the Waste Isolation Pilot Plant,” 

DOE/WIPP-02-3122, Revision 7.4, Carlsbad, New Mexico, April 22, 2013.
10

M-3. EPA found the NABC calibration and verification measurements to be technically adequate 

and appropriately documented for assaying SLB2s in the five-foot setback configuration.

6.7 Changes to Gamma Operating Range

The operating range of the NABC was unchanged due to the use of the five-foot setback 

configuration with SLB2s.

6.8 Specific Limits on Assay Conditions for the Five-Foot Setback

The measurement configuration is limited to 55-gallon drums, SWBs and SLB2s in the 

efficiency-based nonattenuated spectrum, i.e., the multicurve, density-based assay mode. 

Specifically excluded from this evaluation is the use of mass-based/efficiency-based assay mode

for assaying any container.

6.9 Lower Limit of Detection Determination

The lower limits of detection (LLD) for SLB2s in the far-field configuration were not performed.

According to SRS-CCP, the two containers that the NABC assayed in the five-foot setback 

configuration were previously assayed in the near-field configuration and exhibited high deadtimes apparently attributable to 238Pu. SRS-CCP stated that because they knew the containers’ 

TRU content would exceed 100 nCi/g, they did not establish the LLD for the five-foot setback 

configuration for SLB2s. However, SRS-CCP stated that if this T1 request been for a general 

population of containers this information would not be known and an LLD would have been 

established.

SRS-CCP expects to use the far-field setback configuration for SLB2s to assay containers with 

easily measureable concentrations of TRU radionuclides, as discussed previously, and this 

application was adequately demonstrated. However, LLDs for the five-foot setback configuration 

for SLB2s were not demonstrated and accordingly this configuration is not approved to

discriminate TRU and non-TRU wastes in accordance with the 100 nCi/g criterion.

6.10 Total Measurement Uncertainty

The determination of total measurement uncertainty (TMU) for the NABC is addressed in 

“Savannah River Gamma Box Counter Calibration Report Alternatives for Non-Destructive 

Assay (NDA) of Large Containers to Allow Shipping in TRUPACT III without Resizing and/or 

Repackaging,” Canberra Document No. 40945. The determination of TMU is not affected by the 

five-foot setback configuration with SLB2s.

7.0 FINDINGS AND CONCERNS

There were no findings or concerns regarding the use of the five-foot setback configuration for 

the assay of SLB2s on the SRS-CCP NABC.
11

8.0 CONCLUSIONS

Changes to Tiering

As a result of this evaluation, EPA did not make any changes to the SRS-CCP CH T1 and T2 

designations that were established during the baseline approval and modified during subsequent 

T1 evaluations. The tiering designations presented in Table 1 of the final report for EPA’s 

approval of the five-foot setback for assaying SWBs (see EPA Docket No. A-98-49; II A4 171; 

February 21, 2013) remain in effect.

Approval

During this T1 evaluation, EPA evaluated the use of a new measurement configuration for

SLB2s on the BSGS aspect of the NABC. Based on this evaluation, EPA approves the use of the 

five-foot setback configuration to assay SLB2s for the BSGS aspect of the NABC. Because the 

BNAS aspect of the NABC is unchanged, the gamma data from the five-foot setback 

configuration of the BSGS may be used in conjunction with BNAS-derived neutron values, as 

described in this report, at the discretion of the SRS-CCP EA. However, at this time, the fivefoot setback configuration for assaying SLB2s is not approved to discriminate TRU and nonTRU wastes in accordance with the 100 nCi/g criterion, based on the technical documentation 

SRS-CCP provided. 
A-1

ATTACHMENT A

APPROVAL SUMMARY FOR SRS-CCP CONTACT-HANDLED WASTE 

CHARACTERIZATION PROGRAM

Approved Activity EPA Inspection Number, 

Approval Dates EPA Docket Number

SRS-CCP CH Baseline Approval

EPA-SRS-10.05-8 

July 2006

A-98-49; II-A4-65

T1 Change – Approval of Segmented Gamma Scanner, 

Nondestructive Assay System

August 2007 A-98-49; II-A4-90

T1 Change – Approval of Nondestructive Assay Box Counter, 

Nondestructive Assay System

August 2009 A-98-49; II-A4-114

T1 Change – Addition of S3000 Solids March 2010 A-98-49; II-A4-123

T1 Change – Extension of the Calibrated Range of the NABC 

BSGS to 7.18 g

238Pu Using a 20-Minute Counting Time

September 2010 A-98-49; II-A4-133

T1 Change – Changing to an Efficiency-based Calibration for 

NABC BSGS

May 2011 A-98-49; II-A4-148

T1 Change – NABC BSGS 5-ft Setback for 55-gallon drums September 2012 A-98-49; II-A4-166

T1 Change – NABC BSGS 5-ft Setback for SWBs February 2013 A-98-49; II-A4-171
B-1

ATTACHMENT B

NONDESTRUCTIVE ASSAY BOX COUNTER EVALUATION CHECKLIST– FAR-FIELD 

GEOMETRY FOR STANDARD LARGE BOXES TYPE 2 GEOMETRY

Technical Elements Objective Evidence

Confirm the NDA system is the NABC, its location and

number.

This is the same NDA system as EPA previously evaluated and approved, located in Building 643-43E in E Area

of the Savannah River Site near Aiken, South Carolina.

Confirm any changes to the NABC. No physical changes to system, only change is relocating the gamma detectors, no changes to the neutron aspect

of the NABC are connected to the FFG.

Describe the NABC. The HPGe detectors were physically moved approximately five feet further away from their initial position. This

distance was chosen because it is the maximum sample-to-detector distance possible with the detectors remaining

inside the NABC enclosure. EPA observed this configuration of the NABC in operation at SRS. There are no

other physical changes to the NABC.

Identify the measurement conditions for the NABC FFG:

Container(s) type:

Assay Mode (Neutron and/or Gamma):

Counting Mode: Attenuated or Sum-of-Segments: WG

and/or HS Pu:

Attenuators: Filter(s):

Dead-Time Criterion: Assay Time

Revisions of CCP-TP-189, 190 & 193:

Sort TRU/Non-TRU:

Specific Limitations:

Container(s) type: 55-gallon drums, SWBs and SLB2s.

Assay Mode (Neutron and/or Gamma): Change only affects gamma, no change to neutron mode; neutron data 

may be used with near-field or far-field gamma values or AK-derived isotopics.

Counting Mode: Nonattenuated, Sum-of-Segments (multicurve, density-based) efficiency only.

WG and/or HS Pu: Individual contributions from both as well as mixtures are routine.

Attenuators: Not used for FFG.

Filter(s): 0.14 mm Cd, 0.5 mm Cu.

Dead-Time Criterion: No specific criterion, depends on spectral quality, generally ~70%; dead time is the limit

but acceptability is determined by the EA on a case-by-case basis.

Assay Time: Typical 60-minute counts without attenuators.

Revisions of CCP-TP-189, -190 & -193: No changes to procedures for FFG for SLB2s.

Sort TRU/Non-TRU: Not always possible, containers are expected to be significantly greater than 100 nCi/g, 

TRU/non-TRU discrimination not demonstrated.

Identify the period of performance relevant to this 

application of the NABC.

This is the first use of the FFG for SLB2s.

Identify the number of waste containers the NABC has 

assayed using the FFG to date beyond the three BDRs 

provided. Confirm that all SLB2s assayed by the NABC 

FFG have rejected prior assay values. Indicate how many 

BDRs were assembled other than the three provided prior 

to the inspection and indicate how many have been 

promoted through Project Level Review.

A total of two SLB2s have been assayed using the FFG as of January 2014, and these were assembled in one 

BDR, which was promoted through Project Level Review and was provided for this EPA evaluation. EPA noted 

that both containers in this BDR had an associated Non Conformance Report (NCR) attributable to elevated Pu 

Equivalent Curie values, which prevented SRS-CCP from shipping them.
B-2

Technical Elements Objective Evidence

Confirm that the NABC FFG is able to report quantitative 

values and uncertainties for 238Pu, 239Pu, 240Pu, 242Pu, 

241Am, 233U, 234U, 238U, 90Sr and 137Cs.

The FFG is able to report quantitative values for

238Pu,239Pu,240Pu,242Pu,241Am,233U, 234U, 238U, 90Sr and

137Cs

in the same manner as the near-field geometry.

Identify any sample conditions, interferences, 

radionuclides or other aspects that are potentially 

problematic or require specific corrections for the NABC 

FFG.

There are many examples, including presence of

244Cm, high concentrations of237Np,241Am,137Cs or238Pu.

Spectra are typically complex and all require considerable interpretation by the EA. All sample spectra reviewed

for this T1 were complex and had to be corrected for potential interferences; corrections are documented in the 

BDR.

Where is the actual efficiency calibration for the NABC 

FFG documented?

Efficiency calibration is documented in “Canberra Factory BSGS 5-Foot Stand-Off ISOCS Calibration Report for 

the SWB Container Type, for BSGS Extended 1-Hour Calibration with Unshielded HPGe Detectors and the 

BSGS Reduced 20-Minute Calibration with Shielded HPGE Detectors.”

Determine if the HPGe and NaI detectors used for the

NABC FFG are the same as used for near-field assays. 

Where are the detectors’ attributes described?

The HPGe detectors are unchanged; the only difference is their proximity to the SLB2, i.e., they are five feet

further away. The detectors’ attributes are described in CCP-SRS-SRBC003 and “Canberra Factory BSGS 5-Foot 

Stand-Off ISOCS Calibration Report for the SWB Container Type, for BSGS Extended 1-Hour Calibration with 

Unshielded HPGe Detectors and the BSGS Reduced 20-Minute Calibration with Shielded HPGE Detectors.”

Detectors are No. 1 (BE382011058149), No. 2 (BE382011058149), No. 3 (BE382011058149) and No. 4

(BE382011058152). The NaI detectors are also the same, Nos. 127B102/5M-EI-NEG, as are the

60Co

transmission sources, ~250 mCi as of May 5, 2005.

Assess the technical adequacy of any changes to the 

calculations involving the application of scaling factors 

and/or correlation techniques as a result of implementing 

the NABC FFG.

Identify the procedures that govern this function and 

where the results of these calculations are documented.

SRS-CCP procedures: CCP-TP-189, Revision 2, for operation; CCP-TP-190, Revision 2, for calibration; CCPTP-193, Revision 3, for data review.

These procedures were not revised as a result of this change. The previous revisions adequately addressed

changing measurement configurationsto allow for assaying 55-gallon drums and SWBs, and SRS-CCP NDA

personnel stated that these revisions applied to this change in configuration for SLB2s. EPA accepted this.

Identify any changes to the method(s) used to derive the 

isotopic contribution for the unmeasured radionuclides, 

e.g., MGA, FRAM or other technique as a result of the 

NABC FFG.

Identify any changes to the method or details of the TMU 

calculation as a result of the NABC FFG.

Due to the spectra complexities, MGA is typically not used but FRAM is often helpful. There is considerable

spectral interpretation by the EA and this is often the most important aspect of deriving isotopics for FFG

samples.

The TMU derivation is fundamentally unchanged, although the values of the input vary with each assay.