DOCKET NO: A-98-49; II-A4-114 

WASTE CHARACTERIZATION REPORT 

TIER 1 CHANGE: 

EVALUATION OF THE GAMMA AND PASSIVE NEUTRON OPERATIONAL MODES 

OF THE NON DESTRUCTIVE ASSAY BOX COUNTER FOR THE 

NONDESTRUCTIVE ASSAY BOX COUNTER (NABC) AT THE CENTRAL 

CHARACTERIZATION PROJECT (CCP) AT SAVANNAH RIVER SITE (SRS) 

March 24–26, 2009

U.S. Environmental Protection Agency 

Office of Radiation and Indoor Air 

Center for Waste Management and Regulations 

1200 Pennsylvania Avenue, NW

Washington, DC 20460 

August 2009
i

TABLE OF CONTENTS 

Section Page

1.0 Executive Summary ............................................................................................................ 1 

2.0 Purpose of Inspections ........................................................................................................ 1 

3.0 Purpose of This Report........................................................................................................ 2 

4.0 Scope of Review.................................................................................................................. 2 

5.0 T1 Evaluation Personnel ..................................................................................................... 2 

6.0 Evaluation of the NABC ..................................................................................................... 3 

7.0 Summary of Results and Conclusions............................................................................... 20 

8.0 Approval............................................................................................................................ 20 

LIST OF ATTACHMENTS 

Attachment A: EPA Inspection Issue Tracking Form No. SRS-CCP-NDA-T1-NABC-06-

001CR 

Attachment B.1: Replicate Testing Data for Container SR510464 – 55-gallon drum 

Attachment B.2: Replicate Testing Results for Container SR510464 – 55-gallon drum 

Attachment B.3: Replicate Testing Data for Container SR61125902 – SLB2 

Attachment B.4: Replicate Testing Results for Container SR61125902 – SLB2 

LIST OF TABLES 

Table 1. T1 Evaluation Personnel ............................................................................................... 3 

Table 2. BNAS Calibration Confirmation Results for 55-gallon Drum.................................... 11 

Table 3. BNAS Calibration Confirmation Results for SWB .................................................... 12 

Table 4. BNAS Calibration Confirmation Results for SLB-2 .................................................. 13 

Table 5. 252Cf Values and 238Pu Equivalences .......................................................................... 13 

Table 6. Assay Results for 238Pu Equivalent 252Cf Standards for 55-gallon Drum................... 14 

Table 7. Assay Results for 238Pu Equivalent 252Cf Standards for SWB.................................... 14 

Table 8. Assay Results for 238Pu Equivalent 252Cf Standards for SLB-2.................................. 15 

Table 9. Contributors to TMU for BSGS.................................................................................. 16 

Table 10. Contributors to TMU for BNAS for Typical Waste Matrices .................................... 17 
1

1.0 EXECUTIVE SUMMARY 

In accordance with 40 CFR 194.8(b), the U.S. Environmental Protection Agency (EPA or the 

Agency) conducted Baseline Inspection No. EPA-SRS-10.05-8 of the Central Characterization 

Project (CCP) waste characterization program for contact-handled (CH) transuranic (TRU) 

wastes at the U.S. Department of Energy (DOE) Savannah River Site (SRS) in Aiken, South 

Carolina, from October 31 through November 3, 2005. As a result of this baseline inspection, 

EPA approved the SRS-CCP CH TRU waste characterization program with conditions and 

limitations, as discussed in the SRS Baseline Final Inspection Report (see EPA Docket No. 

A-98-49, II-A4-64). This approval included two nondestructive assay (NDA) systems, the IQ3 

gamma system for assaying soil/gravel and debris waste, and the Imaging Passive Active 

Neutron (IPAN) system for assaying debris waste. 

On March 9, 2009, the Carlsbad Field Office (CBFO) requested EPA approval of a Tier 1 (T1) 

change to add the Nondestructive Assay Box Counter (NABC) at SRS. The NABC is a bimodal 

system consisting of a gamma detection mode referred to as the Box Segmented Gamma System 

(BSGS) and a neutron detection mode referred to as the Box Neutron Assay System (BNAS). 

On March 24–26, 2009, EPA conducted an onsite evaluation of the NABC at SRS, during which 

an issue relating to the operational range for 238Pu was identified. In late July EPA received a 

revised calibration report from SRS-CCP that documented additional performance testing, which 

more thoroughly characterized the 238Pu range and technical justification for the correlation of 

252Cf and 238Pu neutrons. EPA reviewed this document and found it adequately addressed the 

concern. Based on EPA’s evaluation of all SRS-CCP activities relative to the NABC, EPA 

approves the NABC for assaying CH TRU waste, consistent with the limitations discussed in this 

report. 

This report serves as EPA’s public notification of the results of the proposed T1 change and its 

evaluation. This information will be provided through the EPA web site and by sending e-mails 

to the WIPPNEWS list, in accordance with 40 CFR 194.8(b)(3). This approval does not make 

any changes to the tiering table provided with the baseline approval. 

 

2.0 PURPOSE OF INSPECTIONS 

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 WIPP. An EPA 

inspection team conducts an on-site inspection to verify that the site’s system of controls is 

technically adequate and properly implemented. 

 
2

Following the 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 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’s 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 approving the NABC for use 

in assaying CH TRU wastes at SRS. This report documents the basis for EPA’s approval 

decision and explains the results of the technical evaluation of the system, including its range 

limitation. 

EPA’s approval decision regarding the SRS-CCP NABC has been conveyed to DOE separately 

by letter. As discussed previously, EPA will also announce the decision on its web site at 

www.epa.gov/radiation/WIPP, in accordance with 40 CFR 194.8(b)(3). 

4.0 SCOPE OF REVIEW

The NABC is located at SRS, E Area, Building 643-43E, and is operated by SRS-CCP. It is a 

bimodal system consisting of a BSGS gamma detection mode and a BNAS neutron detection 

mode. The NABC is configured for CH TRU wastes in three container types (geometries): 

55-gallon (208-Liter) drums; standard waste boxes (SWBs); and standard large boxes (SLB-2s).1

 

Throughout this report, the term all three container types refers to these three container types. 

During this T1 evaluation, EPA assessed the NABC with respect to its ability to identify and 

quantify the activities of the 10 WIPP-tracked radionuclides and their uncertainty, determine a 

technically appropriate lower limit of detection (LLD), and provide technical support for the 

system’s Total Measurement Uncertainty (TMU), as appropriate. These aspects were assessed 

for the gamma and neutron detection modes for all three container types. 

5.0 T1 EVALUATION PERSONNEL 

All personnel involved in this T1 evaluation are shown in Table 1, listed with their professional 

affiliation and function during the onsite evaluation at SRS. 

 

1

 The NABC was also calibrated for the Ten-Drum Overpack (TDOP) geometry, but that container type is 

not included in this T1 evaluation. 
3

Table 1. T1 Evaluation Personnel 

Personnel Name Affiliation TI Evaluation Function 

Ed Feltcorn US EPA EPA Lead Inspector 

Patrick Kelly SC&A/EPA EPA Technical Consultant 

Bob Ceo MCS NDA Senior Scientist 

Joe Wachter MCS MCS Technical Director 

Dan Remington MCS NDA Senior Scientist 

Todd Shepley MCS NDA Lead Operator 

Steve Muse CCP NDA Quality Engineer 

Charlie Riggs CTAC CBFO Technical Support 

Jim Oliver CTAC CBFO Surveillance Lead 

Joe Harvill WTS NDA Support 

Christa Chavez WTS NDA Support 

James Mobley CCP CCP VPM 

Tim Carlton MCS NDA Operations 

Wade Morris MCS BNAS Operations 

Kathy Johns-Hughes SWMF * 

Bert Crapse DOE-SR * 

Mark Pearcy CCP * 

J.D. Chion SRNS * 

Lee Fox SRNS * 

Steve Goff DOE-SR * 

*These individuals were present at the entrance and/or exit meetings on March 24 or 26, 2009. 

These individuals were not actively involved in the T1 evaluation, and are listed for completeness. 

6.0 EVALUATION OF THE NABC 

EPA evaluated the documentation that had been prepared to support the approval of the NABC 

system that will be used to characterize CH TRU wastes at SRS-CCP. The evaluation took place 

on March 24–26, 2009, in the Canberra Offices adjacent to the SRS site in Aiken, South 

Carolina. The EPA evaluation team observed the NABC on site operating in both the gamma 

and neutron modes for a 55-gallon drum and an SLB-2. The evaluation consisted of reviewing 

technical documents prior to the onsite portion in March, followed by an onsite inspection of the 

NABC. As part of the review, EPA evaluated the following elements of the NABC system: 

• Capability of the hardware and software to perform the required analyses for both gamma 

and neutron measurement modes for the three measurement configurations, including 

identifying and quantifying the activities of the 10 WIPP-tracked radionuclides, i.e., 

241Am, 137Cs, 238Pu, 239Pu, 240Pu, 242Pu, 90Sr, 233U, 234U, and 238U, and the associated 

uncertainty of each 

• Technical adequacy of the SRS-CCP documents and procedures to support the NABC’s 

operation in both measurement modes for the three measurement configurations 

• Knowledge and understanding of the personnel involved in the SRS-CCP NDA program 
4

The following documents were examined to assess the NABC: 

• 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, Revision A 

• Savannah River Box Gamma Box Counter Total Measurement Uncertainty Report for 

Alternatives for Non-Destructive Assay (NDA) of Large Containers to Allow Shipping in 

TRUPACT III without Resizing and/or Repackaging, Canberra Document No. 40972, 

Revision A 

• Savannah River Box Neutron Assay System Total Measurement Uncertainty Report for 

Alternatives for Non-Destructive Assay (NDA) of Large Containers to Allow Shipping in 

TRUPACT III without Resizing and/or Repackaging, Canberra Document No. 41309, 

Revision A 

• Nondestructive Assay Box Counter: Calibration Validation and Confirmation Report for 

the Gamma Modality, CCP-SRS-SRBC001, Revision 0, October 23, 2008 and Revision 

1, April 2, 2009 

• Neutron Box Counter Calibration Report for Alternatives for Non-Destructive Assay 

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

Repackaging, Canberra Document No. A40973, Revision 4, 2007 

• Box Neutron Assay System, Factory Calibration and Total Measurement Uncertainty: 

Neutron Box Counter Calibration Report for Alternatives for Non-Destructive Assay 

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

Repackaging, A40973, Revision 04 

• Nondestructive Assay Box Counter: Calibration Validation and Confirmation Report for 

the Neutron Assay Modality, CCP-SRS-SRBC002, Revision 0, December 19, 2008 

• Phase II Acceptance Test Procedure Gamma and Neutron Box Counting System for 

DOE/Savannah River, ACK# 0403973, Revision 7, September 27, 2007 

• Nondestructive Assay Box Counter: Calibration Validation and Confirmation Report For 

the Neutron Modality, CCP-SRS-SRBC002, Revision 1, June 4, 2009 

• Nondestructive Assay Box Counter: Calibration Validation and Confirmation Report For 

the Neutron Modality, CCP-SRS-SRBC002, Revision 2, July 29, 2009 

• Calibration Verification of the SRS-BSGS System Due to HPGe Detector Energy Gain 

Shift, MCS-SRS-BSGS-09-001, Revision 1, March 12, 2009 

• CCP-TP-189, CCP Box Segmented Gamma System (BSGS) Operating Procedure, 

Revision 0, April 30, 2008 

• CCP-TP-190, CCP Box Segmented Gamma System Calibration, Revision 1, August 29, 

2008 

• CCP-TP-191, CCP Box Neutron Assay System (BNAS) Operating Procedure, 

Revision 0, April 30, 2008 
5

• CCP-TP-192, CCP Box Neutron Assay System Calibration Procedure, Revision 1, 

August 27, 2008 

• CCP-TP-193, CCP Data Reviewing, Validating, and Reporting Procedure for the 

Nondestructive Assay Box Counter, Revision 1, August 21, 2008 

• NABC BDR SRLBC001: SLB-2 Nos. SR60685706, SR61125902 and FBLBOX3702 

• NABC BDR SRLBC002: SWB Nos. SWB0114, SWB0113 and SWB0058 

• NABC BDR SRLBC003: 55-gallon drum Nos. SR502014 and SR510464 

• NABC BDR SRLBC004: 55-gallon drum No. SR519002 

• SRS List of Qualified Individuals (LOQI), March 10, 2009, 4:21:10 PM, including 

NDA/BSGS/BNAS, NDA SGS, NDE, Headspace Gas (Drum Venting and Summa 

Sampling), Flammable Gas for Transportation and Transportation Personnel for SRS 

Only 

• CBFO NTP Memorandum: Approval Status Notification – Supplementary Box Cycle 

B8B of the Nondestructive Assay Performance Demonstration Program, March 27, 2009 

The EPA inspection team assessed the technical elements of the NABC that are discussed below. 

(1) The design and operational range of the NABC were assessed for both gamma and 

neutron assay modes, and were found to be adequate following modification of the 238Pu 

range for the BNAS. 

The NABC integrates two detection modes, gamma and neutron, called the BSGS and the 

BNAS, respectively. It has a moving trolley, which travels on rails past two counting gamma 

counting stations, one for passive counting and one for transmission counting. The passive 

aspect is accomplished with a high-resolution gamma-ray counter that incorporates both density 

(multi-curve) and transmission-based matrix corrections, and uses Multi Group Analysis (MGA) 

Multi Group Analysis-Uranium (MGA-U), and FRAM2

 software for plutonium (Pu) and 

uranium (U) isotopic determination. The BNAS consists of a high efficiency passive neutron 

counter with both coincidence and multiplicity analysis capabilities, including an Add-A-Source 

(AAS) option for matrix corrections. The separate gamma and passive neutron operational 

components of the NABC are equivalent to several NDA systems that EPA has evaluated and 

approved for CH TRU assays at other CCP sites, e.g., Idaho National Laboratory and Los 

Alamos National Laboratory. Radionuclide data for waste containers are derived in one of three 

ways: quantitative values from the BSGS alone; isotopic gamma values from the BSGS that are 

applied to BNAS neutron values; or acceptable knowledge (AK)-based isotopics applied to 

BNAS neutron values. The NABC quantifies specified radionuclides in all three container types. 

By design, the NABC quantifies Pu and other WIPP-tracked and TRU radionuclides, such as 

238Pu, 239Pu, 240Pu, 233U, 235U, 238U, 237Np, 241Am, 243Am, and 137Cs, using a combination of 

gamma and neutron data. Other radionuclides that cannot be quantified directly (234U, 90Sr, and 

 

2

 FRAM is an initialization for a gamma identification and quantification program that is called FixedEnergy Response Function Analysis with Multiple Efficiencies. Both MGA and FRAM are available to the SRSCCP personnel who perform data review and approval.
6

242Pu) are determined using AK, scaling factors, and/or correlation techniques using an adequate 

process. The design and operational range of the gamma and neutron modes are evaluated 

separately below. 

BSGS Design

The BSGS consists of four high purity germanium (HPGe) detectors mounted on two opposite 

towers, with two detectors per tower each at the same vertical distance (height) from the floor. 

The detectors are Broad Energy Germanium (BEGe) detectors with relative efficiencies of 

18.3%, 16.7%, 19.8%, and 19.3% for detector Nos. 1–4, respectively, and all are fitted with 

5.08 cm thick cylindrical lead shielding. The positions of the BEGe detectors relative to the axis 

of container movement through the NABC must be set manually for each of the three container 

types. The technical specifications of the BEGe detectors are documented in CCP-SRSSRBC001. Spectra from the BEGe detectors are used to determine the Pu isotopic content of 

waste containers directly, or using MGA, MGAU, or FRAM for isotopic determination. If 

isotopic data are not available, default isotopics as defined by AK may be used. 

The BSGS also has a transmission assembly consisting of two 60Co sources (~250 mCi each) 

mounted in lead shields on one tower, one on top of the other, approximately 1.5 meters apart. 

Directly opposite the sources (on the other side of the trolley holding the waste containers) are 

two thallium-drifted sodium iodide [NaI(Tl)] gamma detectors. During assay, a waste container 

is located between the 60Co sources and the NaI(Tl) detectors, such that the sources shine 

through the sample and allow the effects of the matrix on the source intensity to be quantified. 

Each 60Co source is housed in a shield containing a tungsten shutter that opens and closes to 

permit it to “shine” directly at a NaI(Tl) detector when open, or be shielded by the shutters in the 

closed position. The shutters can be manipulated to optimize the source intensity for different 

container sizes and matrix densities. Like the BEGe detectors, the transmission sources and 

NaI(Tl) detectors must be positioned manually for each of the three container geometries, i.e., at 

different heights, depending on the container size being assayed. The transmission 

measurements are relative determinations that are used for matrix corrections based on 

established regions of interest (ROIs) for the 1,173 and 1,332 keV peaks of 60Co. The system is 

shown in Canberra Document No. 40945, Figures 1, 2, and 3. Canberra’s NDA 2000 software is 

used for acquiring, processing, and managing all gamma data. There are additional components 

that control movement of the container (trolley) and transmission source shutters. 

BSGS Range

The operational range of the BSGS is stated as the system’s LLD [see Item (6), below] to 

204 grams for 239Pu and the LLD to 0.44 grams for 238Pu in terms of (mass) activity. For 

density-based efficiency, a range of 0.02 g/cm3 to 1.62 g/cm3 was established, as summarized in 

CCP-SRS-SRBC001. Canberra Report No. 40945 describes the details of the BSGS calibration 

that was performed using mixed gamma sources [see Item (2), below], and the system’s 

operational range is determined by measurements of weapons grade (WG) and heat source (HS) 

Pu standards, as described in CCP-SRS-SRBC001. For WG Pu, 239Pu sources were assayed over 

a range of <1 gram to approximately 204 grams 239Pu to produce the stated operational range. 

For HS Pu, the operational range is the system LLD to 40 grams 238Pu. 
7

BNAS Design

The BNAS consists of 320 3He proportional tubes in a polyethylene liner of the assay enclosure 

(inner chamber dimensions are 81 inches wide by 120 inches long by 79 inches tall). The 

detector tube outputs are divided among 80 counting channels. This module of the NABC 

determines the 240Pu effective mass (240PuEFF) of the item assayed. The original BNAS 

calibration was performed at the Canberra factory in Meriden, Connecticut, using 252Cf standards 

to determine the system’s basic neutron parameters. Once these were established, the AAS 

technique was used to correct for matrix effects on neutrons emitted within the waste container. 

The AAS mechanism accurately positions a 252Cf source at different points in a tube located in 

the floor of the assay enclosure and, following a preset time, retracts it into a shielded storage 

box external to the enclosure. To calibrate the AAS, a small 252Cf source (about 105

 n/s) is 

introduced into the assay cavity with no container in the counter to provide a reference count 

rate. The count rate measurement is repeated with containers loaded with different matrices and 

the observed assay values both with and without a container are compared. The AAS matrix 

correction treats the waste matrix as a perturbation on the response from an empty container in 

the counter and provides a matrix-specific numerical correction. The 252Cf source is used to 

perform the AAS correction, and also serves as the reference standard for the system’s daily 

performance check. The result of the passive neutron assay is a value expressed in terms of 

240PuEFF for any of the three container types. 

BNAS Operational Range

The operational range of the BNAS is stated as the system’s LLD [see Item (6), below] to 305 g 

of 239Pu for WG Pu and the LLD to 40 g for 238Pu, as summarized in MCS-SRS-NDA-0810, 

Revision 2. Canberra Report No. A40973 describes the details of the BNAS calibration that was 

performed using 252Cf sources [see Item (2), below], and the system’s operational range is 

determined by measurements of WG and HS Pu standards in conjunction with 252Cf standards to 

serve as 238Pu surrogates for neutron emission, as described in MCS-SRS-NDA-0810, 

Revision 2, Attachment 2. 

(2) The NABC’S calibrations for the gamma and neutron modes were evaluated and were 

found to be adequate for all three container geometries. 

BSGS Calibration

The gamma calibrations were performed at Canberra’s facility in Meriden, Connecticut, for all 

three geometries. The NABC was also calibrated for the Ten-Drum Overpack (TDOP) 

geometry, but that container type is not included in this T1 evaluation. Mixed gamma sources 

supplied by North American Scientific Inc., were used, and the sources were of the appropriate 

pedigree. The gamma-emitting radionuclides included 241Am, 57Co, 133Ba, 137Cs and 60Co. 

Three NBL CRM Pu standards were used to demonstrate successful MGA execution, and five 

NBS SRM 969 type U standards were used to demonstrate successful execution of MGAU. 

Certificates for all mixed gamma, Pu, and U standards were provided and were acceptable. 
8

Q2-type matrix drums for the 55-gallon container size included the following five materials: 

empty container, ρ = 0.00 g/cm3

; foam, ρ = 0.045 g/cm3; Homasote, ρ = 0.473 g/cm3; particle 

board, ρ = 0.725 g/cm3

; and sand, ρ = 1.52 g/cm3. The matrices for the SWB and SLB-2 

containers were composed of a variety of materials in varying percentages, as follows: 

• 100% cardboard, ρ = 0.152 g/cm3

• 42.55% plywood and 57.45% cardboard, ρ = 0.297 g/cm3

• 32.65% poly, 48.98 % plywood and 18.73% cardboard, ρ = 0.580 g/cm3

• 80.85% poly and 19.15% plywood, ρ = 0.780 g/cm3

• Low density PE foam, ρ = 0.0027 g/cm3

• High density PE foam, ρ = 0.64 g/cm3

• Cardboard, ρ = 0.152 g/cm3

• Plywood, ρ = 0.565 g/cm3

The matrix efficiencies for the SWBs and SLB-2s were derived based on In-Situ Object 

Counting System (ISOCS) models over a range of energies from 59.5 keV to 1,332.5 keV and 

were compared to measured values for 55-gallon drums, SWBs and SLB-2s as shown in 

Canberra Document No. 40945, Tables 9 and 10. Transmission calibrations were performed 

using the low (shutter partially closed) and high (shutter open) modes by measuring through a 

moderate density material. 

BNAS Calibration

 

Calibration of the BNAS was performed at the Canberra facility in Meriden, Connecticut, by 

determining Add-A-Source (AAS) calibration parameters and other system characteristics, 

including high voltage, counting efficiency, die-away time, gate fractions, and dead-time 

parameters. These were determined for all three geometries. AAS calibration matrix correction 

factors were determined for each container type using 252Cf sources at a variety of (decaycorrected) neutron emission rates from 2.147E+03 to 2.054E+06 n/s, as listed in Canberra Report 

No. A40973, Appendix A, Table 1. Certificates for all 252Cf standards were provided and were 

acceptable with one exception. The certification sheet for 252Cf source No. A3-468 was not 

legible with respect to its stated activity in microcuries (μCi), a fundamentally important aspect; 

the correct value activity of the source is 53.40 μCi as of January 1, 2002. This was discussed in 

the onsite evaluation at SRS in March of this year, but it was not corrected in Revision 1 of the 

calibration report. However, Revision 2 contained a legible copy of the certification sheet. 

Q2-type matrix drums for the 55-gallon container size included the following materials and 

densities: 

• Polyethylene, ρ = 0.26 g/cm3

 and 0.73 g/cm3

• Cellulose, ρ = 0.35 g/cm3

 and 0.66 g/cm3

• Borosillicate glass, ρ = 0.26 g/cm3

5 and 0.44 g/cm3

• Lead, ρ = 2.0 g/cm3

• Softboard, ρ = 0.04 g/cm3

• Particle board, ρ = 0.72 g/cm3
9

• 65 kg PolyVerm, ρ = 0.31 g/cm3

• 29 kg PolyVerm, ρ = 0.13 g/cm3

• 100% Poly, ρ = 0.59 g/cm3

The matrices used in the SWB and SLB-2 container geometries for the neutron calibration and 

gamma calibration are the same as shown above. Acceptable ranges of AAS correction factors 

were established for the three container types, and expert review is required for all assay values 

outside of these ranges, as shown in MCS-SRS-NDA-0810, page 3. 

After review of the revised the calibration report there are no technical concerns regarding the 

adequacy of the calibration of the gamma and neutron modes of the NABC and its supporting 

documentation. 

(3) Calibration confirmation and verification of the NABC had been performed and 

documented as required for the gamma and neutron modes and for all three measurement 

configurations. 

BSGS Calibration Confirmation

The approach taken by Canberra included calibration validation measurements and calibration 

confirmation measurements, which is more than what is required by DOE/WIPP-02-3122, 

Appendix A. EPA’s perspective is that there must be technically credible objective evidence that 

the calibration has been verified, and CCP-SRSR-SRBC001 provides this for all three container 

types. What Canberra calls a calibration validation amounts to a demonstration of the system’s 

operational range in the efficiency-based and transmission-corrected gamma modes. This was 

performed using the same set of NIST traceable mixed gamma line sources that were used for the 

initial calibration in Connecticut, with the appropriate decay correction. Assays were performed 

in a cardboard or particleboard matrix in the efficiency-based and transmission-corrected modes. 

Precision and accuracy were demonstrated by determining the relative standard deviation 

(%RSD) and percent recovery (%R) of the average of three assays. All %RSD values were 

within ± 6.6% (based on three replicate assays) for all assay configurations for all three 

containers. All %R values were within ± 30% for the 55-gallon drum. The %R values were 

within ± 30% for the SWB and SLB-2 assays, except for 

241Am for all assay configurations of 

the SWB and one assay configuration of the SLB-2. These %R values were considerably higher, 

e.g., as high as 217%. This was caused by quantifying 241Am on the basis of the most intense 

photon line at 59 keV, instead of using the higher energy lines at 125 keV, 662 keV and 

722 keV. The 241Am source was too weak to provide sufficient counts in the higher energy 

regions to enable their use in quantification, and the matrix is over corrected, resulting in a 241Am 

value that is biased high. For routine assays, SRS-CCP personnel will have to monitor the use of 

the 59 keV line. The validation values are shown in CCP-SRS-SRBC001, Tables 6A and 6B for 

the 55-gallon drum; Tables 7A through 7D for the SWB; and, Tables 8A through 8D for the 

SLB-2. 

Calibration confirmation measurements were performed using different sources from those used 

for calibration. Specifically, the 55-gallon drum and SWB used WG Pu source loadings of 

1.001 g, 25.375 g, and 217.589 g. The SLB-2 source loadings were slightly different at 1.001 g, 
10

26.180 g, and 217.589 g WG Pu. All three containers used a 0.528 g HS Pu source. These 

source loadings were assayed in accordance with CCP-TP-189, and the resulting data were 

evaluated against the criteria in DOE/WIPP-02-3122, Appendix A, Table 3.2, as appropriate. 

The results are provided in Tables 12A, 12B, and 12C. All assays passed the %R criteria for 

accuracy and the %RSD criteria for precision. 

 

BNAS Calibration Confirmation

The BNAS operating range was verified by assaying WG Pu and HS Pu sources over a range of 

masses, which consist primarily of 239Pu and 238Pu, respectively, because WG Pu and HS Pu 

have different 240PuEFF values. The calibration and/or operating ranges for both Pu types begin at 

the system’s LLD [see Item (6)], and the discussion below focuses on establishing the upper end 

of the range for each Pu type. 

WG Pu (High-239Pu) Range: Three nominal 239Pu loadings of 1 g, 24 g, and 204 g were assayed 

for each of the three container types; 55-gal Drum, SWB, and SLB-2. The 1 g 239Pu loading is 

near the low end of the calibration range, the 24-g 239Pu loading is in the lower one-third of the 

calibration range, and the 204 g 239Pu loading is in the upper one-third of the calibration range. 

The 204 g 239Pu loading is the maximum quantity practically attainable using the sources 

available to SRS-CCP. 

HS Pu (High-238Pu) Range: The total 238Pu content in the three HS Pu sources available to SRSCCP is 0.4316 g. Using that quantity of 238Pu to establish the upper assay limit would result in a 

limit of about 0.65 g 238Pu, assuming that the measured value of 0.4316 g is equivalent to the mid 

point of the bottom third of the range. Based on the expectation that waste containers will 

contain 238Pu masses well above 30 g, SRS-CCP wanted to establish a higher calibration limit for 

the BNAS. Accordingly, a 252Cf source was used to simulate the neutron output of a larger 238Pu 

source, an approach that is technically acceptable. A CCP-SRS 252Cf source (Source ID A3-468) 

had a decay-corrected neutron emission rate equivalent to 27 g 238Pu, and using the data from 

this source, SRS-CCP personnel derived an upper calibration limit of 40 g for 238Pu, based on the 

assumption that the highest measured point is equivalent to the mid point of the upper third of 

the range. Using this approach, SRS-CCP derived a calibration range based on two points that 

were considerably far apart, i.e., 0.65 grams and 27 grams. However, the EPA technical 

specialist determined that these two points were inadequate to sufficiently characterize this 

operating/calibration range. Accordingly, EPA did not accept the LLD to 40 g operational range 

for 238Pu proposed by SRS-CCP. Following the onsite evaluation, SRS-CCP obtained additional 

252Cf sources that were assayed as calibration validations, as discussed in Item (4), to further 

populate the 238Pu calibration curve in response to EPA’s concern. The 0.4316 g 238Pu assays 

were acceptable in all three container geometries. EPA ultimately accepted the upper limit of the 

operating range for 238Pu as 40 g, as discussed in this report. 

 

Precision and accuracy were demonstrated by determining the %RSD and %R of four source 

loadings: 0.9386 g, 23.7340 g, and 203.6807 g of WG Pu (239Pu); and 0.4316 g HS Pu (238Pu). 

Each source loading was assayed six times in each of the three measurement geometries 

(containers) and the data were evaluated relative to the appropriate criteria for six replicates in 
11

DOE/WIPP-02-3122, Appendix A, Table A.4.2. The results for each container are summarized 

below. 

55-gallon Drum: The %RSD values range from 0.2% to 3.5%, and all values are within the limit 

of 14% for six replicate measurements. The %R values range from 80.7% to 110.3%, and all are 

within the required 70% to 130% range. The 55-gallon results are shown in Table 2. 

Table 2. BNAS Calibration Confirmation Results for 55-gallon Drum 

Reference Value Assay Measured 240PuEFF g Measured 239Pu g Results 

0.9386 g 239Pu 1 0.0551 0.852 Assay Average: 0.857 

 2 0.0550 0.851 Standard Deviation: 0.0091 

 3 0.0556 0.860 Precision (%RSD): 1.1% 

 4 0.0560 0.866 Accuracy (%R): 91.3% 

 5 0.0547 0.845 

 6 0.0561 0.868 

23.7340 g 239Pu 1 1.618 25.0 Assay Average: 25.0 

 2 1.620 25.0 Standard Deviation: 0.1378 

 3 1.628 25.1 Precision (%RSD): 0.6% 

 4 1.596 24.7 Accuracy (%R): 105.1% 

 5 1.613 24.9 

 6 1.617 25.0 

203.6807 g 239Pu 1 14.53 225 Assay Average: 225 

 2 14.49 224 Standard Deviation: 0.5164 

 3 14.55 225 Precision (%RSD): 0.2% 

 4 14.54 225 Accuracy (%R): 110.3% 

 5 14.46 224 

 6 14.58 225 

0.4316 g 238Pu 1 0.900 0.353 Assay Average: 0.349 

 2 0.910 0.357 Standard Deviation: 0.0121 

 3 0.842 0.330 Precision (%RSD): 3.5% 

 4 0.918 0.360 Accuracy (%R): 80.7% 

 5 0.902 0.354 

 6 0.861 0.337 

SWB: The precision %RSD values range from 0.47% to 4.0%, and all values are within the 

limit of 14% for six replicate measurements. The %R values range from 91.6% to 116.4%, and 

all are within the required 70% to 130% range. The SWB results are shown in Table 3. 

SLB-2: The precision %RSD values range from 0.5% to 3.1%, and all values are within the 

limit of 14% for six replicate measurements. The accuracy %R values range from 92.5% to 

113.6%, and all are within the required 70% to 130% range. The SLB-2 results are shown in 

Table 4. 

Calibration confirmation results for all three measurement geometries were acceptable. There 

are no issues regarding calibration confirmation of the NABC. 
12

Table 3. BNAS Calibration Confirmation Results for SWB 

Reference Value Assay Measured 240PuEFF g Measured 239Pu g Results 

0.8580 g 239Pu 1 0.0576 0.890 Assay Average: 0.902 

 2 0.0562 0.867 Standard Deviation: 0.0359 

 3 0.0560 0.866 Precision (%RSD): 4.0% 

 4 0.0580 0.896 Accuracy (%R): 105.1% 

 5 0.0609 0.940 

 6 0.0615 0.950 

24.4627 g 239Pu 1 1.844 28.5 Assay Average: 28.5 

 2 1.843 28.5 Standard Deviation: 0.133 

 3 1.843 28.5 Precision (%RSD): 0.47% 

 4 1.857 28.7 Accuracy (%R): 116.4% 

 5 1.842 28.4 

 6 1.834 28.3 

203.6809 g 239Pu 1 15.23 235 Assay Average: 235 

 2 15.18 235 Standard Deviation: 1.10 

 3 15.28 236 Precision (%RSD): 0.47% 

 4 15.17 235 Accuracy (%R): 115.4% 

 5 15.10 233 

 6 15.26 236 

0.4316 g 238Pu 1 1.152 0.451 Assay Average (g): 0.468 

 2 1.201 0.471 Standard Deviation: 0.169 

 3 1.169 0.458 Precision (%RSD): 3.6% 

 4 1.273 0.499 Accuracy (%R): 108.5% 

 5 1.173 0.460 

 6 1.199 0.470 
13

Table 4. BNAS Calibration Confirmation Results for SLB-2 

Reference Value Assay Measured 240PuEFF g Measured 239Pu g Results 

0.8580 g 239Pu 1 0.0500 0.772 Assay Average: 0.794 

 2 0.0499 0.771 Standard Deviation: 0.0229 

 3 0.0514 0.794 Precision (%RSD): 2.9% 

 4 0.0533 0.823 Accuracy (%R): 92.5% 

 5 0.0531 0.820 

 6 0.0508 0.784 

24.4627g 239Pu 1 1.788 27.6 Assay Average: 27.8 

 2 1.808 27.9 Standard Deviation: 0.1751 

 3 1.806 27.9 Precision (%RSD): 0.6% 

 4 1.781 27.5 Accuracy (%R): 113.5% 

 5 1.802 27.8 

 6 1.805 27.9 

203.6809 g 239Pu 1 14.91 230 Assay Average: 232 

 2 14.94 231 Standard Deviation: 1.0488 

 3 14.97 231 Precision (%RSD): 0.5% 

 4 15.09 233 Accuracy (%R): 113.6% 

 5 15.00 232 

 6 15.00 232 

0.4316 g 238Pu 1 1.122 0.440 Assay Average (g): 0.462 

 2 1.171 0.459 Std Dev (g): 0.0143 

 3 1.219 0.478 Precision (%RSD): 3.1% 

 4 1.217 0.477 Accuracy (%R): 107.0% 

 5 1.178 0.462 

 6 1.161 0.455 

(4) Calibration validation for all three measurement geometries using 252Cf sources had been 

performed and documented, as required for the NABC.

Following the onsite evaluation in March, SRS-CCP obtained additional 252Cf standards to 

further populate the 238Pu calibration curve between the two previously obtained measurements 

of 0.44 g (238Pu) and 27 g (252Cf). Due to the general unavailability of 238Pu, 252Cf is used as a 

surrogate neutron source for 238Pu, a technically acceptable practice that we have observed at 

other DOE sites (e.g., DWAS at ORNL). SRS-CCP personnel stated they were doing this to 

provide better technical support for the 238Pu calibration curve, as had been requested during the 

initial evaluation. Revision 1 of the calibration report did not include documentation of the 

method used to derive an equivalency for 252Cf and 238Pu neutrons. This conversion is not 

intuitively obvious, and it requires documentation that can be reviewed and verified by 

independent calculation. This information was supplied in Revision 2 of the calibration report 

that was provided electronically, and was verified by independent calculation. The 252Cf source 

activity values in μCi and their corresponding 238Pu equivalency in grams are listed in Table 5. 

Table 5. 252Cf Values and 238Pu Equivalences 

252Cf Source No. 252Cf Activity, μCi 238Pu Equivalent, g 

GI-489 2.435 6.89 

GI-490 5.671 16.0 

D8-360 75 27.0 
14

The 252Cf sources were assayed in all three geometries, and the results subjected to acceptance 

criteria from DOE-WIPP-02-3122 DOE/WIPP-02-3122 for accuracy (%R) and precision 

(%RSD), as shown in Tables 6 through 8. All results were acceptable. 

Table 6. Assay Results for 238Pu Equivalent 252Cf Standards for 55-gallon Drum 

238Pu Equivalent 240Pueff238Pu Results 

6.89 19.6 7.67 Assay Average: 7.62 

 19.3 7.57 Standard Deviation: 0.0455 

 19.3 7.57 Precision (%RSD): 0.6% 

 19.4 7.59 Accuracy (%R): 110.6% 

 19.5 7.64 

 19.5 7.66 

16.0 46.1 18.1 Assay Average: 18.2 

 46.8 18.3 Standard Deviation: 0.0894 

 46.2 18.1 Precision (%RSD): 0.5% 

 46.5 18.2 Accuracy (%R): 113.8% 

 46.6 18.3 

 46.4 18.2 

27.0 76.8 30.1 Assay Average: 30.0 

 76.6 30.0 Standard Deviation: 0.0577 

 76.6 30.0 Precision (%RSD): 0.2% 

 Accuracy (%R): 111.2% 

Table 7. Assay Results for 238Pu Equivalent 252Cf Standards for SWB 

238Pu Equivalent 240Pueff238Pu Results 

6.89 19.7 7.73 Assay Average: 7.71 

 19.7 7.72 Standard Deviation: 0.0306 

 19.7 7.73 Precision (%RSD): 0.4% 

 19.7 7.72 Accuracy (%R): 111.9% 

 19.7 7.72 

 19.5 7.65 

16.0 46.7 18.3 Assay Average: 18.3 

 46.6 18.3 Standard Deviation: 0.0548 

 46.6 18.2 Precision (%RSD): 0.3% 

 46.6 18.2 Accuracy (%R): 114.4% 

 46.6 18.3 

 46.5 18.2 

27.0 76.7 30.0 Assay Average: 30.0 

 76.5 30.0 Standard Deviation (g): 0.0000 

 76.4 30.0 Precision (%RSD): 0.0% 

 Accuracy (%R): 111.1% 
15

Table 8. Assay Results for 238Pu Equivalent 252Cf Standards for SLB-2 

238Pu Equivalent 240Pueff238Pu Results 

6.89 19.3 7.56 Assay Average: 7.56 

 19.3 7.56 Standard Deviation (g): 0.0063 

 19.3 7.56 Precision (%RSD): 0.8% 

 19.3 7.55 Accuracy (%R): 109.7% 

 19.3 7.57 

 19.3 7.56 

16.0 45.9 18.0 Assay Average: 18.0 

 45.9 18.0 Standard Deviation: 0.0000 

 46.0 18.0 Precision (%RSD): 0.0% 

 46.0 18.0 Accuracy (%R): 112.5% 

 45.9 18.0 

 45.9 18.0 

27.0 73.8 28.9 Assay Average: 29.0 

 74.0 29.0 Standard Deviation: 0.0577 

 73.9 29.0 Precision (%RSD): 0.2% 

 Accuracy (%R): 107.3% 

There are no technical issues with the calibration, calibration confirmation, and calibration 

validation of the NABC in either the gamma or neutron detection modes. 

(5) SRS-CCP had documented all required performance testing for the NABC. 

SRS-CCP had performed and documented technically appropriate performance testing for the 

NABC for both the gamma and neutron operational modes for all three container sizes, as 

required. These are documented in CCP-SRS-SRBC001 for the gamma mode operation and in 

CCP-SRS-SRBC002 for the neutron mode operation. The one exception was the exclusion of 

performing Weekly Interfering Matrix Checks (WMCs) for the SLB-2 geometry. This was 

discussed with SRS-CCP personnel during the evaluation and was captured on an EPA 

Inspection Issue Tracking Form (see Attachment A for a copy of this form), and it is discussed 

below. 

EPA Inspection Issue Tracking Form, Issue No. SRS-CCP-NDA-T1-NABC-06-001CR, 

Final: The SRS-CCP Report CCP-SRS-SRBC001, Section 4.4.4, addresses WMCs that will be 

performed in 55-gallon drums and SLB-2s, but does not address performing WMCs in SWBs. 

SRS-CCP personnel stated they will perform WMCs in SWBs and that the lack of mention in 

CCP-SRS-SRBC001 was a simple omission. SRS-CCP personnel committed to revising CCPSRS-SRBC001 and to providing a revised copy to EPA upon completion. 

Resolution: Following the onsite evaluation, SRS-CCP personnel provided an electronic copy 

of Revision 1 of CCP-SRS-SRBC001, which was modified to address EPA’s concern and which 

included other minor changes. 

Status of Concern: SRR-CCP’s revision of CCP-SRS-SRBC001, Section 4.4.4, adequately 

addressed EPA’s concern, and this concern is closed. 
16

There were no concerns regarding the performance and documentation of performance testing 

for the gamma and/or neutron operational modes for the NABC resulting from this T1 

evaluation. 

(6) The total measurement uncertainty (TMU) of assays performed on the NABC had been 

determined and documented, as required. 

BSGS TMU Determination

The determination of the gamma component of the 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. This report was prepared by Canberra in 

Meriden, Connecticut, and it addresses TMU for all three container sizes. Consistent with what 

we have observed previously for other NDA systems, the sources of TMU are addressed with the 

assumption that all sources are independent, which allows them to be added in quadraure, i.e., 

taking the square root of the sum of the squares of each contributor to TMU. A summary of 

contributors listed by container size is shown in Table 9, and all values are listed in percent, 

stated at 1 σ (standard deviation): 

Table 9. Contributors to TMU for BSGS 

Contributor to TMU 55-Gallon Drum SWB SLB-2 

Counting Statistics <5% <5% <5% 

Calibration 3% 3% 3%

Rate Loss Correction <0.5% <0.5% <0.5% 

Matrix Inhomogeneity 20% 20% 20%

Non-Uniform Source Distribution * * * 

Background <1% <1% <1%

Radionuclide Interference <1% <1% <1% 

Self Attenuation/Lumps * * * 

Isotopic Determination * * * 

Fill Height 5% 5% 5%

Multi-Curve/Transmission Corrections 8% 8% 8%

Other * * * 

Total TMU 27% 40% 50%

*Variable, on the order of several percent, assay-event specific. 

All aspects of TMU for the BSGS were technically adequate and appropriately documented. 

There are no issues with the determination and documentation of TMU for the BSGS aspect of 

the NABC. 

BNAS TMU Determination

The determination of the neutron of the TMU for the NABC is addressed in Savannah River Box 

Neutron Assay System Total Measurement Uncertainty Report for Alternatives for NonDestructive Assay (NDA) of Large Containers to Allow Shipping in TRUPACT III without 

Resizing and/or Repackaging, Canberra Document No. 41309. This report was prepared by 

Canberra in Meriden, Connecticut, and it addresses TMU for all three container sizes. 
17

Consistent with what we have observed previously for other NDA systems, the sources of TMU 

are addressed with the assumption that all sources are independent, which allows them to be 

added in quadraure. Each contributor was evaluated for two matrices—a low moderating matrix 

(ρ = 0.35 g/cm3

) and a highly moderating matrix (ρ = 0.59 g/cm3), as shown in Table 10—and all 

values are listed in percents stated at 1 σ (standard deviation). 

Table 10. Contributors to TMU for BNAS for Typical Waste Matrices 

Contributor to TMU 55-Gallon Drum

Low 0.35 g/cm3

55-Gallon Drum 

High 0.59 g/cm3

SWB-Low 

0.35 g/cm3

SWB-High 

0.59 g/cm3

SLB-2 Low 

0.35 g/cm3

SLB-2 High 

0.59 g/cm3

Counting Statistics 1% 2% 1% 5% 1% 5% 

Calibration 2% 2% 2% 2% 2% 2% 

AAS Correction 2% 8% 3% 7% 2% 5% 

Min/Average Ratio <1% <1% <1% <1% <1% <1% 

Max/Average Ratio 1% 4% 1% 5% 1% 6% 

Matrix Source Dist 7% 27% 2% 35% 0% 50% 

Fill Height 1% 55% 5% 70% 3% 47% 

Background (100 kg 

Steel) 

<1% <1% <1% <1% 10% 50% 

Isotopics 10% 10% 10% 10% <1% <1% 

Multiplication Effects 0% 0% 0% 0% 10% 10% 

Total TMU, 

Nominal 

13% 63% 12% 80% 15% 86%

*Variable, on the order of several percent, assay-event specific. 

The values in this table should be seen as bounding estimates. For example, the source 

distribution values assume a worst-case scenario with small lumps of Pu in a metal matrix or a 

layered sludge, assuming approximately 10 g of WG Pu and a ratio of alpha n-produced neutrons 

to spontaneous fission neutrons of 3 [(α,n)/(SF,n)]. In reality, routine assays would probably 

exhibit less drastic conditions. Due to the short operating history of the NABC and the 

complexity of modeling several of the uncertainty contributors for a large geometry, EPA may 

examine Batch Data Reports at a later date to assess the model’s accuracy. 

All aspects of TMU for the BNAS were technically adequate and appropriately documented. 

There are no issues with the determination and documentation of TMU for the BNAS aspect of 

the NABC. 

(7) The LLD, including the minimum detectable concentration of the NABC, had been 

determined and documented for the gamma and neutron operational modes. 

The LLD definition used by SRS-CCP is consistent with that specified in DOE/WIPP-02-3122 

(CH WAC). Specifically, the LLD is defined as “that level of radioactivity which, if present, 

yields a measured value greater than the critical level with a 95% probability, where the critical 

level is defined as that value which measurements of the background will exceed with 5% 

probability.” The LLD of any given NDA measurement is a function of the type of 

measurement, the measurement time, the properties of the waste matrix being assayed, and the 

environmental background. For this reason, the LLD will vary from container to container, and 

may even vary between measurements of the same container. The LLD for the BSGS and 

BNAS are discussed separately below. 
18

BSGS LLD Determination

The 55-gallon drum filled with the Homasote matrix and no radioactive sources was assayed 

three times using the standard operating protocols, as documented in CCP-TP-189. Each LLD 

value was corrected for the matrix (net weight) and MDC values were derived.3

 These assays 

were used to generate LLD values for 238Pu, 239Pu, 240Pu, 233U, 235U, 238U, 137Cs, and 241Am in 

both the efficiency-based and transition-corrected gamma modes. All results were acceptable. 

The SWB filled with a cardboard matrix and no radioactive sources was assayed three times 

using the standard operating protocols, as documented in CCP-TP-189. Each LLD value was 

corrected for the matrix (net weight) and MDC values were derived. These assays were used to 

generate LLD values for 238Pu, 239Pu, 240Pu, 233U, 235U, 238U, 137Cs, and 241Am in both the 

efficiency-based and transition-corrected gamma modes. All results were acceptable. 

The SLB-2 filled with a cardboard matrix and no radioactive sources was assayed three times 

using the standard operating protocols, as documented in CCP-TP-189. Each LLD value was 

corrected for the matrix (net weight) and MDC values were derived. These assays were used to 

generate LLD values for 238Pu, 239Pu, 240Pu, 233U, 235U, 238U, 137Cs, and 241Am in both the 

efficiency-based and transition-corrected gamma modes. All results were acceptable. 

Reporting thresholds are required for the radionuclides that are not measured directly; 

specifically 242Pu, 234U and 90Sr. Additionally, SRS-CCP determined a different 242Pu threshold 

for WG-Pu and HS-Pu. Since these radionuclides are scaled to one or more measured 

radionuclides, the reporting thresholds were determined by applying the appropriate correction to 

the measured values. SRS-CCP personnel stated that it is not technically feasible to derive a 

reporting threshold for 234U. 

All gamma-based LLDs and reporting thresholds are documented in CCP-SRS-SRBC001. There 

are no concerns regarding the determination and/or documentation of gamma-based LLDs or 

reporting thresholds for the NABC. 

BNAS LLD Determination 

Nominal BNAS LLDs were determined from three replicate counts of three container/matrix 

configurations without radioactive sources, using the PDP4

 Combustibles 55-gallon drum and 

cardboard matrices for the SWB and SLB-2. To convert the observed values in 240Pueff to total 

plutonium mass, the values were corrected for either WG Pu or HS Pu isotopics, and meaningful 

LLD values and reporting thresholds were derived. They are shown in MCS-SRS-NDA-0810, 

Tables 15–19, and these values are considered typical or representative, i.e., the minimum 

detectable quantity of each measured radionuclide for each waste container assay is calculated 

and reported, based on the data from that assay. All results were acceptable. The LLD values 

for WG Pu for all containers are less than 100 nCi/g, and the BNAS can be used to perform 

 

3

 MDC and MDA are the minimum detectable concentration and minimum detectable activity, respectively. 

Both can be considered equivalent to an LLD for the purpose of this report. 

4

 PDP sources are constructed by Los Alamos National Laboratory for use in the CBFO-sponsored NDA 

Performance Demonstration Program. 
19

TRU/Non TRU discrimination. However, for HS Pu, only materials that were heavier than what 

was used for the LLD determinations would provide a sufficient concentration to be less than 

100 nCi/g, particularly for the 55-gallon drum. Accordingly, SRS-CCP has stated that the BNAS 

will not be used to discriminate between TRU and Non-TRU for HS Pu-bearing wastes. 

All neutron-based LLDs and reporting thresholds are documented in MCS-SRS-NDA-0810. 

There are no concerns regarding the determination and/or documentation of neutron-based LLDs 

or reporting thresholds for the NABC. 

(8) The NABC had successfully participated in the CBFO-sponsored PDP, as required. 

The NABC participated in Cycle B8B of the CBFO-sponsored NDA PDP. This cycle included 

two matrices and two activity types, and one TRU alpha activity range; specifically, an SWB 

with a combustible matrix and WG Pu at greater than 2 Ci TRU alpha activity; and an SWB with 

a mixed metals matrix and HS Pu at greater than 2 Ci TRU alpha activity. SRS-CCP submitted 

data for this cycle on March 5, 2009, and successful participation was documented in a March 

27, 2009, approval letter. There are no issues with the participation of the NABC in the CBFOsponsored PDP. 

 

(9) EPA replicate testing of the NABC unit was performed and evaluated, and was found to 

comply with the criteria for the EPA Replicate Testing Protocol. 

The purpose of the replicate testing performed as part of this inspection is to provide EPA with 

an independent means to verify that the NABC can provide reproducible results for the 

determination of the quantity of 10 WIPP-tracked radionuclides (241Am, 137Cs, 238Pu, 239Pu, 

240Pu, 242Pu, 90Sr, 233U, 234U, and 238U) and the TRU alpha concentration.5

 This is accomplished 

by re-assaying containers previously measured on the same system, in order to demonstrate the 

system’s ability to do the following: 

• Produce results consistent with the reported TMU by comparing the sample standard 

deviation for a number of replicate measurements taken over several hours or days to the 

reported TMU. 

• Provide reproducible results over longer periods of time, such as weeks or months, by 

comparing the results of the replicate measurement(s) to the original reported values. 

As part of EPA’s evaluation of the NABC, EPA requested that the NABC re-assay two 

containers that EPA randomly selected from a list of previously assayed 55-gallon drums and 

SLB-2s. EPA did not select an SWB, because the intention was to evaluate the NAB by 

focusing on the two ends of the system’s size range. It was assumed that the system’s response 

for the SLB-2 and the SWB would be equivalent. EPA chose 55-gallon drum No. SR510464 and 

SLB-2 No. SR61125902. Both containers were re-assayed on the NABC unit five times, and the 

data for the five replicates and the original assay were analyzed using two statistical tests, a chisquared (χ2

) test, and a t-test. The EPA inspection team observed operation of the NABC as it 

 

5

 Revision 2 of the EPA Replicate Testing Protocol provides the details of the replicate testing assay protocol 

and data evaluation. 
20

performed the assay of SLB-2 No. SR61125902. Attachments B.1–B.4 include data and results 

of the statistical analysis for all assays. 

The t-test for both containers assayed on the NABC did not show any statistically significant 

differences between the original measurement assay values and the average of the five replicate 

measurements for the activities of any of the target radionuclides or the TRU alpha activity 

concentration. The χ2

 test for all containers assayed on the NABC showed that the observed 

variances in the replicate measurements are less than or equal to the reported uncertainties within 

the statistical limits of the test. There are no technical issues associated with replicate testing of 

the NABC. 

7.0 SUMMARY OF RESULTS AND CONCLUSIONS 

The EPA inspection did not identify any findings related to the NABC during this T1 evaluation. 

EPA did identify one concern, which is discussed in the preceding section. Attachment A of this 

report provides the EPA Inspection Issue Tracking Form that documents this issue. EPA 

received a revised document to address this issue following the onsite evaluation. EPA considers 

this issue to be closed, and there are no open concerns related to the NABC at SRS-CCP 

resulting from this evaluation. 

8.0 APPROVAL 

During this T1 evaluation, the EPA inspection team evaluated the NABC located at DOE’s SRS, 

E Area, Building 643-43E that is operated by SRS-CCP. It is a bimodal system (neutron and 

gamma operational modes), and it is configured for CH TRU wastes in three container types 

(geometries); 55-gallon drums, SWBs, and SLB-2s. EPA assessed the operation of the NABC 

for all three container types. Based on this T1 evaluation, the NABC is approved for assaying 

CH TRU wastes in the gamma and neutron detection modes for the three measurement 

configurations—55-gallon drum, SWB, and SLB-2—consistent with the limitations described in 

this report.
A-1 

ATTACHMENT A: EPA INSPECTION ISSUE TRACKING FORM NO. SRS-CCPNDA-T1-NABC-06-001CR 

T1 Evaluation No.: SRS-CCP-T1-NABC-03-09 Issue Number: SRSCCPNDAT1NABC06001CR, 

Final 

Date: 3-25-09 

Inspector: Patrick Kelly 

Attachments?  Yes  No 

Sample Size: NA 

Population size (if known): NA 

A. Description of Issue: The SRSCCP report CCPSRSSRBC001, Section 4.4.4, addresses Weekly 

Matrix Checks (WMCs) that will be performed in 55-gallon drums and SLB2s, but does not address 

WMCs in Standard Waste Boxes (SWBs). SRSCCP personnel stated that WMCs will be run in SWBs. 

B. Regulatory Reference: 40 CFR 194.24 (c)(4) 

C. Site requirement(s): Not Applicable

D. Discussed with: Daniel Remington, Bob Ceo, Joe Harvill, Christa Chavez, Todd Shepley, and Joe 

Wachter 

E. Additional Comments: None 

F. Site Response Information: 

Site Response Required?  Yes  No 

Site Response Due Date: Not Applicable 
B-1 

ATTACHMENT B.1: REPLICATE TESTING DATA FOR CONTAINER SR510464 – 55-GALLON DRUM 

Instrument: SRS NABC Container: SR510464 (208-Liter Drum ) 

Original Measurement Replicate #1 Replicate #2 

Quantity of Interest Reported 

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported 

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported 

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

233U Activity (Ci) 2.27E-03 0.00E+00 0.00E+00 2.25E-03 0.00E+00 0.00E+00 2.41E-03 0.00E+00 0.00E+00 234U Activity (Ci) 3.36E-05 0.00E+00 0.00E+00 3.33E-05 0.00E+00 0.00E+00 3.28E-05 0.00E+00 0.00E+00 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 238Pu Activity (Ci) 4.08E-04 0.00E+00 0.00E+00 2.74E-04 0.00E+00 0.00E+00 4.78E-04 0.00E+00 0.00E+00 239Pu Activity (Ci) 5.73E-03 0.00E+00 0.00E+00 5.38E-03 0.00E+00 0.00E+00 6.71E-03 0.00E+00 0.00E+00 240Pu Activity (Ci) 1.30E-03 0.00E+00 0.00E+00 1.02E-03 0.00E+00 0.00E+00 1.41E-03 0.00E+00 0.00E+00 242Pu Activity (Ci) 1.81E-09 0.00E+00 0.00E+00 1.68E-09 0.00E+00 0.00E+00 1.48E-09 0.00E+00 0.00E+00 241Am Activity (Ci) 6.27E-01 0.00E+00 0.00E+00 6.42E-01 0.00E+00 0.00E+00 6.42E-01 0.00E+00 0.00E+00 90Sr Activity (Ci) 1.56E-05 0.00E+00 0.00E+00 1.58E-05 0.00E+00 0.00E+00 1.59E-05 0.00E+00 0.00E+00 137Cs Activity (Ci) 1.56E-05 0.00E+00 0.00E+00 1.58E-05 0.00E+00 0.00E+00 1.59E-05 0.00E+00 0.00E+00 TRU Alpha Conc. (nCi/g) 3.17E+04 0.00E+00 0.00E+00 3.25E+04 0.00E+00 0.00E+00 3.26E+04 0.00E+00 0.00E+00 

Replicate #3 Replicate #4 Replicate #5 

Quantity of Interest Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

233U Activity (Ci) 2.37E-03 0.00E+00 0.00E+00 2.28E-03 0.00E+00 0.00E+00 2.11E-03 0.00E+00 0.00E+00 234U Activity (Ci) 3.38E-05 0.00E+00 0.00E+00 3.36E-05 0.00E+00 0.00E+00 3.29E-05 0.00E+00 0.00E+00 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 238Pu Activity (Ci) 3.71E-04 0.00E+00 0.00E+00 3.75E-04 0.00E+00 0.00E+00 3.64E-04 0.00E+00 0.00E+00 239Pu Activity (Ci) 6.18E-03 0.00E+00 0.00E+00 5.92E-03 0.00E+00 0.00E+00 5.25E-03 0.00E+00 0.00E+00 240Pu Activity (Ci) 1.32E-03 0.00E+00 0.00E+00 1.17E-03 0.00E+00 0.00E+00 1.13E-03 0.00E+00 0.00E+00 242Pu Activity (Ci) 3.43E-09 0.00E+00 0.00E+00 1.18E-09 0.00E+00 0.00E+00 2.21E-09 0.00E+00 0.00E+00 241Am Activity (Ci) 6.38E-01 0.00E+00 0.00E+00 6.48E-01 0.00E+00 0.00E+00 6.31E-01 0.00E+00 0.00E+00 90Sr Activity (Ci) 1.58E-05 0.00E+00 0.00E+00 1.58E-05 0.00E+00 0.00E+00 1.59E-05 0.00E+00 0.00E+00 137Cs Activity (Ci) 1.58E-05 0.00E+00 0.00E+00 1.58E-05 0.00E+00 0.00E+00 1.59E-05 0.00E+00 0.00E+00 TRU Alpha Conc. (nCi/g) 3.23E+04 0.00E+00 0.00E+00 3.28E+04 0.00E+00 0.00E+00 3.19E+04 0.00E+00 0.00E+00 
B-2 

ATTACHMENT B.2: REPLICATE TESTING RESULTS FOR CONTAINER SR510464 – 55-GALLON DRUM 

Instrument: SRS NABC 

Container: SR510464 ( 208-Liter Drum ) 

Original Measurement 

Quantity of Interest Reported

Value 

Absolute 

Uncertainty

Sample 

Mean 

Sample 

Standard 

Deviation

Relative 

Standard

Deviation

χ

2 Pr(x

<|χ2|) 

233U Activity (Ci) 2.27E-03 0.00E+00 2.28E-03 1.17E-04 5.12E-02 N/A N/A 234U Activity (Ci) 3.36E-05 0.00E+00 3.33E-05 4.32E-07 1.30E-02 N/A N/A 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A #VALUE! #VALUE!238Pu Activity (Ci) 4.08E-04 0.00E+00 3.72E-04 7.23E-05 1.94E-01 N/A N/A 239Pu Activity (Ci) 5.73E-03 0.00E+00 5.89E-03 5.97E-04 1.01E-01 N/A N/A 240Pu Activity (Ci) 1.30E-03 0.00E+00 1.21E-03 1.55E-04 1.28E-01 N/A N/A 242Pu Activity (Ci) 1.81E-09 0.00E+00 2.00E-09 8.85E-10 4.43E-01 N/A N/A 241Am Activity (Ci) 6.27E-01 0.00E+00 6.40E-01 6.26E-03 9.78E-03 N/A N/A 90Sr Activity (Ci) 1.56E-05 0.00E+00 1.58E-05 5.48E-08 3.46E-03 N/A N/A 137Cs Activity (Ci) 1.56E-05 0.00E+00 1.58E-05 5.48E-08 3.46E-03 N/A N/A TRU Alpha Conc. (nCi/g) 3.17E+04 0.00E+00 3.24E+04 3.42E+02 1.06E-02 N/A N/A 

Quantity of Interest t Pr(x <|t|) χ2 Test t Test

233U Activity (Ci) -1.09E-01 9.18E-01 Not Applicable Not Significant 234U Activity (Ci) 6.76E-01 5.36E-01 Not Applicable Not Significant 238U Activity (Ci) N/A N/A #VALUE! Not Applicable 238Pu Activity (Ci) 4.49E-01 6.76E-01 Not Applicable Not Significant 239Pu Activity (Ci) -2.41E-01 8.21E-01 Not Applicable Not Significant 240Pu Activity (Ci) 5.30E-01 6.24E-01 Not Applicable Not Significant 242Pu Activity (Ci) -1.92E-01 8.57E-01 Not Applicable Not Significant 241Am Activity (Ci) -1.92E+00 1.27E-01 Not Applicable Not Significant 90Sr Activity (Ci) -4.00E+00 1.61E-02 Not Applicable Significant 137Cs Activity (Ci) -4.00E+00 1.61E-02 Not Applicable Significant TRU Alpha Conc. (nCi/g) -1.92E+00 1.27E-01 Not Applicable Not Significant 
B-3 

ATTACHMENT B.3: REPLICATE TESTING DATA FOR CONTAINER SR61125902 – SLB2 

Instrument: SRS NABC 

Container: SR61125902 (SLB-2) 

Original Measurement Replicate #1 Replicate #2 

Quantity of Interest Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported 

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

233U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 234U Activity (Ci) 1.06E-04 0.00E+00 0.00E+00 1.04E-04 0.00E+00 0.00E+00 1.05E-04 0.00E+00 0.00E+00 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 238Pu Activity (Ci) 5.97E-01 0.00E+00 0.00E+00 5.87E-01 0.00E+00 0.00E+00 5.95E-01 0.00E+00 0.00E+00 239Pu Activity (Ci) 1.04E-02 0.00E+00 0.00E+00 9.72E-03 0.00E+00 0.00E+00 8.78E-03 0.00E+00 0.00E+00 240Pu Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 242Pu Activity (Ci) 1.83E-07 0.00E+00 0.00E+00 1.80E-07 0.00E+00 0.00E+00 1.82E-07 0.00E+00 0.00E+00 241Am Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 90Sr Activity (Ci) 3.19E-07 0.00E+00 0.00E+00 3.37E-07 0.00E+00 0.00E+00 3.44E-07 0.00E+00 0.00E+00 137Cs Activity (Ci) 3.19E-07 0.00E+00 0.00E+00 3.37E-07 0.00E+00 0.00E+00 3.44E-07 0.00E+00 0.00E+00 TRU Alpha Conc. (nCi/g) 7.66E+02 0.00E+00 0.00E+00 7.52E+02 0.00E+00 0.00E+00 7.62E+02 0.00E+00 0.00E+00 

Replicate #3 Replicate #4 Replicate #5 

Quantity of Interest Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

Reported

Value 

Absolute 

Uncertainty

Relative 

Uncertainty

233U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 234U Activity (Ci) 1.08E-04 0.00E+00 0.00E+00 1.06E-04 0.00E+00 0.00E+00 1.04E-04 0.00E+00 0.00E+00 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 238Pu Activity (Ci) 6.10E-01 0.00E+00 0.00E+00 5.99E-01 0.00E+00 0.00E+00 5.85E-01 0.00E+00 0.00E+00 239Pu Activity (Ci) 8.75E-03 0.00E+00 0.00E+00 9.22E-03 0.00E+00 0.00E+00 9.55E-03 0.00E+00 0.00E+00 240Pu Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 242Pu Activity (Ci) 1.87E-07 0.00E+00 0.00E+00 1.83E-07 0.00E+00 0.00E+00 1.79E-07 0.00E+00 0.00E+00 241Am Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 0.00E+00 N/A 0.00E+00 90Sr Activity (Ci) 3.19E-07 0.00E+00 0.00E+00 3.33E-07 0.00E+00 0.00E+00 3.60E-07 0.00E+00 0.00E+00 137Cs Activity (Ci) 3.19E-07 0.00E+00 0.00E+00 3.33E-07 0.00E+00 0.00E+00 3.60E-07 0.00E+00 0.00E+00 TRU Alpha Conc. (nCi/g) 7.81E+02 0.00E+00 0.00E+00 7.67E+02 0.00E+00 0.00E+00 7.51E+02 0.00E+00 0.00E+00 
B-4 

ATTACHMENT B.4: REPLICATE TESTING RESULTS FOR CONTAINER SR61125902 – SLB2 

Instrument: SRS NABC

Container: SR61125902 (SLB-2)

Original Measurement 

Quantity of Interest Reported

Value 

Absolute 

Uncertainty 

Sample 

Mean 

Sample 

Standard 

Deviation 

Relative 

Standard 

Deviation 

χ

2 Pr(x

<|χ2|) 

233U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A #VALUE! #VALUE!234U Activity (Ci) 1.06E-04 0.00E+00 1.05E-04 1.67E-06 1.59E-02 N/A N/A 238U Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A #VALUE! #VALUE!238Pu Activity (Ci) 5.97E-01 0.00E+00 5.95E-01 1.01E-02 1.69E-02 N/A N/A 239Pu Activity (Ci) 1.04E-02 0.00E+00 9.20E-03 4.39E-04 4.77E-02 N/A N/A 240Pu Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A #VALUE! #VALUE!242Pu Activity (Ci) 1.83E-07 0.00E+00 1.82E-07 3.11E-09 1.71E-02 N/A N/A 241Am Activity (Ci) 0.00E+00 N/A 0.00E+00 0.00E+00 N/A #VALUE! #VALUE!90Sr Activity (Ci) 3.19E-07 0.00E+00 3.39E-07 1.50E-08 4.44E-02 N/A N/A 137Cs Activity (Ci) 3.19E-07 0.00E+00 3.39E-07 1.50E-08 4.44E-02 N/A N/A TRU Alpha Conc. (nCi/g) 7.66E+02 0.00E+00 7.63E+02 1.23E+01 1.61E-02 N/A N/A 

Quantity of Interest t Pr(x <|t|) χ2 Test t Test

233U Activity (Ci) N/A N/A #VALUE! Not Applicable 234U Activity (Ci) 3.27E-01 7.60E-01 Not Applicable Not Significant 238U Activity (Ci) N/A N/A #VALUE! Not Applicable 238Pu Activity (Ci) 1.63E-01 8.78E-01 Not Applicable Not Significant 239Pu Activity (Ci) 2.49E+00 6.78E-02 Not Applicable Not Significant 240Pu Activity (Ci) N/A N/A #VALUE! Not Applicable 242Pu Activity (Ci) 2.34E-01 8.26E-01 Not Applicable Not Significant 241Am Activity (Ci) N/A N/A #VALUE! Not Applicable 90Sr Activity (Ci) -1.19E+00 3.00E-01 Not Applicable Not Significant 137Cs Activity (Ci) -1.19E+00 3.00E-01 Not Applicable Not Significant TRU Alpha Conc. (nCi/g) 2.52E-01 8.13E-01 Not Applicable Not Significant