DOCKET NO: A-98-49; II-A4-133

WASTE CHARACTERIZATION REPORT

TIER 1 CHANGE:

EVALUATION OF THE EXTENSION OF THE CALIBRATION RANG E FOR THE BOX GAMMA SEGMENTED SYATEM (BSGS) OF THE NONDESTRUC TIVE ASSAY BOX COUNTER (NABC) AT THE CENTRAL CHARACTERIZATION PROJECT

(CCP) AT SAVANNAH RIVER SITE (SRS)

U.S. Environmental Protection Agency

Office of Radiation and Indoor Air Center for Waste Management and Regulations 1200 Pennsylvania Avenue, NW Washington, DC 20460

September 2010i TABLE OF CONTENTS

Section Page

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

................................................... .........................1

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

................................................... ..........................1

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

................................................... .........................1

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

................................................... ............................2

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

................................................... ........................2

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

................................................... .......................2

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

................................................... ..............6

8.0 Approval ..........................................

................................................... .................................7

LIST OF TABLES

Table 1. Approval Summary for SRS-CCP CH Waste Char acterization Program .........................1

Table 2. T1 Evaluation Personnel ..................

................................................... ...............................2 Table 3. Plutonium Mass Loading Contents for Contai ner Type .......................................... ..........51

1.0 EXECUTIVE SUMMARY

In accordance with 40 CFR 194.8(b), the U.S. Enviro nmental Protection Agency (EPA or the Agency) conducted Baseline Inspection No. EPA-SRS-1 0.05-8 of the Central Characterization Project (CCP) waste characterization program for co ntact-handled (CH) transuranic (TRU) wastes at the U.S. Department of Energy (DOE) Savan nah 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 characterizat ion 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 nond estructive assay (NDA) systems: the IQ3 gamma system and the Imaging Passive Active Neutron (IPAN) system.

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 referre d 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 evaluati on of the NABC at SRS and approved the NABC. A summary of all EPA approvals of SRS-CCP’s CH TRU waste characterization program is provided in Table 1, below. On July 8, 2009, the CBFO requested EPA approval of a T1 change to extend the calibration range of the BS GS aspect of the NABC to 7.18 grams of

238 Pu utilizing a reduced 20-minute assay time and tha t change is the subject of this evaluation.

This report serves as EPA’s public notification of the results of the proposed T1 change and its evaluation. This information will be provided throu gh the EPA web site and by sending e-mails to the WIPPNEWS list, in accordance with 40 CFR 194 .8(b)(3). As a result of this approval no changes were made to the modified tiering table pro vided with the approval of S3000 (solid)

waste in March 2010.

Table 1. Approval Summary for SRS-CCP CH Waste Char acterization Program

Specific SRS-CCP CH Approval Date EPA Docket Number

SRS CH Baseline Approval July 2006 A-98-49; II-A4-64

Tier 1 Change – Approval of Segmented Gamma Scanner

, Nondestructive Assay System August 2007 A-98-49; II-A4-90

Tier 1 Change – Approval of Nondestructive Assay Bo x Counter, Nondestructive Assay System August 2009 A-98-49; II-A4-114

Tier 1 Change – Addition of S3000 Solids March 2010 A-98-49; II-A4-1231

2.0 PURPOSE OF INSPECTIONS

Any changes to the waste characterization activitie s 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 th e 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 baseli ne 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 adequate ly characterize TRU wastes and comply with the regulatory requirements imposed on TRU wastes d estined for disposal at the WIPP. An EPA inspection team conducts an onsite inspection to ve rify that the site’s system of controls is technically adequate and properly implemented.

Following the EPA’s approval of waste characterizat ion processes evaluated during the baseline inspection, EPA is authorized to evaluate and appro ve, if necessary, changes to the site’s approved waste characterization program by conducti ng 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 wast e and remains in compliance with all the regulatory requirements. Based on the adequacies of the waste characterization processes demonstrated during the baseline inspection, includ ing all conditions and limitations, EPA specified which subsequent waste characterization p rogram 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-CC P’s characterization program. T1 activities have more stringent reporting requirements and requ ire 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 evaluatio n of a T1 change approving the extension of the BSGS aspect of the NABC calibration range for u se 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 any l imitations.

EPA’s approval decision regarding the SRS-CCP NABC calibration range extension 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).

The DOE documents that EPA reviewed for this evalua tion are cited in several places in the report. Any of these documents can be requested fr om:2 Carlsbad Field Office Manager, National TRU Program US Department of Energy

PO Box 3090

Carlsbad NM 88221-3090

4.0 SCOPE OF REVIEW

The NABC is located at SRS, E Area, Building 643-43 E, and is operated by SRS-CCP. It is a bimodal system consisting of the BSGS gamma detecti on mode and the BNAS neutron detection mode. The NABC is configured for CH TRU wastes in t hree container types (geometries): 55-gallon (208-liter) drums; standard waste boxes ( SWBs); and standard large boxes (SLB-2s). During this T1 evaluation, EPA assessed the BSGS as pect of the NABC with respect to extending the calibration range to 7.18 grams of 238 Pu utilizing 20-minute assay time. This calibration range extension is only applicable to 5 5-gallon drums and SWBs.

5.0 T1 EVALUATION PERSONNEL

All personnel involved in this T1 evaluation are sh own in Table 1, listed with their professional affiliation and function during the evaluation.

Table 2. T1 Evaluation Personnel

Personnel Name Affiliation TI Evaluation Function Ed Feltcorn US EPA EPA Lead Inspector Patrick Kelly SC&A/EPA EPA Technical Evaluator Rose Gogliotti SC&A/EPA EPA Technical Evaluator

6.0 EVALUATION OF THE NABC

EPA evaluated the documentation that had been prepa red to support the approval of the calibration range change to the BSGS aspect of the NABC system that will be used to characterize CH TRU wastes at SRS-CCP. As part of t he review, EPA assessed the technical adequacy of SRS-CCP documents to support the BSGS a spect of the NABC’s operation for the 55-gallon drum and SWB container configurations wit h the extended calibration range.

The following documents were examined to assess the BSGS aspect of the NABC:

• Nondestructive Assay Box Counter: Calibration Confi rmation Report for the Gamma Modality Utilizing 20-Minute Count Assay Time, CCP- SRS-SRBC003, Revision 2, May 4, 2010

• Waste Characterization Report: Tier 1 Change: Evalu ation of the Gamma and Passive Neutron Operational modes of the Non Destructive As say Box Counter for the Nondestructive Assay Box Counter (NABC) at the Cent ral Characterization Project (CCP) at Savannah River Site (SRS), March 24–26, 20 093

The NABC integrates two detection modes, gamma and neutron, the BSGS and the BNAS, respectively. It has a moving trolley, which travel s on rails past two gamma counting stations, one for passive counting and one for transmission c ounting. The passive aspect is accomplished with a high-resolution gamma-ray counter that incor porates both density (multi-curve) and transmission-based matrix corrections, and uses Mul ti Group Analysis (MGA), Multi Group Analysis-Uranium (MGA-U), and FRAM 1 software for plutonium (Pu) and uranium (U) isotop ic determination. The BSGS consists of four high purit y germanium (HPGe) detectors mounted on two opposite towers, with two detectors per tower e ach at the same vertical distance (height) from the floor. The BNAS consists of a high efficie ncy 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 f rom the BSGS that are applied to BNAS neutron values; or acceptable knowledge (AK)-based isotopics applied to BNAS neutron values. The NABC quantifies specific radionuclides in all t hree container types. By design, the NABC quantifies Pu and other WIPP-tracked and TRU radion uclides, such as 238 Pu, 239 Pu, 240 Pu, 233 U,

235 U, 238 U, 237 Np, 241 Am, 243 Am, and 137 Cs, using a combination of gamma and neutron data. Other radionuclides that cannot be quantified direc tly ( 234 U, 90 Sr, and 242 Pu) are determined using AK, scaling factors, and/or correlation techniques. The design and operational range of the gamma and neutron modes are evaluated separately be low.

BSGS Design

This T1 change has no impact on the design of the B SGS. Further information on its design can be found in the initial EPA approval of the NABC, s ee EPA Docket No. A-98-49; II-A4-114.

BSGS Range

The operational range of the BSGS is stated as the system’s lower limit of detection (LLD) to 305 grams for 239 Pu and the LLD to 7.18 grams for 238 Pu in terms of (mass) activity using a 20-minute assay time. This is a change to the previ ously approved range of the LLD to 204 grams for 239 Pu and the LLD to 0.44 grams for 238 Pu. For density-based efficiency, an operational range of 0.02 g/cm 3 to 1.62 g/cm 3 was established, as summarized in CCP-SRSSRBC003, which was unchanged by the proposed range extension. Canberra Report No. 40945

describes the details of the BSGS calibration that was performed using mixed gamma sources and the system’s operational range was determined b y measurements of weapons grade (WG) and heat source (HS) Pu standards, as described in CCP-SRS-SRBC003. For WG Pu, 239 Pu sources were assayed over a range of approximately 1 gram to 305 grams 239 Pu to produce the stated operational range. For HS Pu, the operationa l range is the system LLD to 40 grams 238 Pu. Note that operational or calibrated ranges may be s tated in a variety of terms, i.e., WG Pu, 239 Pu,

1 FRAM is an initialization for a gamma identificati on and quantification program that is called Fixed- Energy Response Function Analysis with Multiple Efficienci es. Both MGA and FRAM are available to the SRS-CCP personnel who perform data review and approval.4

HS Pu, 238 Pu or total Pu, all of which are interchangeable wi th the appropriate numerical adjustment for isotopics.

BNAS Design and Operational Range

The BNAS consists of 320 3 He proportional tubes in a polyethylene liner of th e assay enclosure (inner chamber dimensions are 81 inches wide by 120 inches long by 79 inches tall). The operational range of the BNAS is stated as the syst em’s LLD to 305 g of 239 Pu for WG Pu and the LLD to 40 g for 238 Pu, as summarized in MCS-SRS-NDA-0810, Revision 2. The BNAS component of the NABC is unaffected by the T1 chang e and further information on its design and operating range can be found in CCP-SRS-SRBC003

.

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. After reviewing the revised calibration report, there are no changes to the ini tial factory calibration for the BSGS. There are no technical concerns regarding the adequacy of the calibration of the BSGS aspect of the NABC and its supporting documentation.

BNAS Calibration

Calibration of the BNAS was performed at the Canber ra facility in Meriden, Connecticut, by determining Add-a-Source (AAS) calibration paramete rs and other system characteristics, including high-voltage, counting efficiency, die-aw ay time, gate fractions, and dead-time parameters. This module of the NABC is unaffected b y the T1 change and further information on

the BNAS calibration can be found in CCP-SRS-SRBC00 1, see EPA Docket No. A-98-49; IIA4-114.

BSGS Calibration Confirmation

To comply with requirements established in DOE/WIPP -02-3122 Appendix A-1 Section A.3, calibration confirmation measurements must be prefo rmed after each calibration or recalibration. The confirmation must meet the followi ng criteria:

• Replicate measurements must be made with a non-inte rfering matrix

• Containers must be of the same nominal size as wast e containers to be assayed

• Number of replicates must be documented and technic ally justified

• Items used for calibration confirmation must contai n nationally recognized standards, or standards derived from nationally recognized standa rds, whose contents span the range of

use

• Standards used to establish accuracy shall not be t he same as those used for calibration

• Accuracy (%R of the content of record) shall not ex ceed ±30%

• Precision (%RSD) must meet criteria listed in Table A 3.2, DOE/WIPP-02-3122 Appendix A5

Confirmation measurements were initially performed for three WG plutonium loadings, and one HS Pu loading, in each of the two container types, 55-gallon drums and SWBs. The WG and HS Pu mass loadings for each container type used in ca libration confirmation are listed in Table 2.

Table 3. Plutonium Mass Loading Contents for Contai ner Type

55-Gallon Drum SWB

WG Pu 1.001 g 1.001 g 25.375 g 25.375 g 217.589 g 217.589 g

HS Pu 0.538 g 0.528 g

Calibration confirmation measurements were performe d using different sources from those used for system’s initial calibration. These sources wer e assayed in accordance with CCP-TP-189, Revision 1, and the resulting data were evaluated a gainst the criteria in DOE/WIPP-02-3122, Appendix A, Table 3.2, as appropriate. The results are provided in CCP-SRS-SRBC003. The mass loadings for the initial 20-minute count time calibration confirmation measurements were determined by combining standards available through SRS to produce a range of values. Each 55-gallon drum was continuously rotated during the 1200-second confirmation measurement. The WG and HS Pu configurations were each assayed s ix times to provide sufficient data for statistical analysis. All assays passed the ±30%R c riteria for accuracy and the %RSD criteria for precision (14% for six repetitions). The calibratio n confirmation measurement results for the 20- minute assays are documented in CCP-SRS-SRBC003. Th ere are no concerns regarding the technical adequacy or documentation of the calibrat ion confirmation for the BSGS aspect of the

NABC.

BNAS Calibration Confirmation

The BNAS operating range was unaffected by this T1 change. Calibration confirmation for BNAS was performed during the initial approval of t he NABC at SRS, see EPA Docket No. A98-49; II-A4-114.

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 i n TRUPACT III without Resizing and/or Repackaging, Canberra Document No. 40945. The BSGS TMU is unaffected by this T1 change.

BNAS TMU Determination

The determination of the BNAS aspect of TMU for the NABC is addressed in Savannah River Box Neutron Assay System Total Measurement Uncertai nty Report for Alternatives for Non Destructive Assay (NDA) of Large Containers to Allo w Shipping in TRUPACT III without Resizing and/or Repackaging, Canberra Document No. 41309. The BNAS TMU was not affected by this T1 change.6

BSGS LLD Determination

The 55-gallon drum filled with the Homasote matrix and no radioactive sources was assayed three times using the new 20-minute assay time and standard operating protocols, as documented in CCP-TP-189, Revision 1. For each assay, NDA 2000 software was used to calculate the LLDs and minimum detectable activities (MDAs) for the te n WIPP tracked radionuclides plus 235 U. Each LLD value was corrected for the matrix (net we ight) to determine the minimum detectable concentration (MDC) for each radionuclide. All resu lts were acceptable and meet the CH-WAC

TRU/non-TRU waste discrimination criterion of 100 n Ci/g. Results are documented in Appendix E-1 of the calibration report. The SWB filled with a cardboard matrix and no radioactive sources was assayed three times using the standard operatin g protocols, as documented in CCP-TP-189,

Revision 1. Each LLD value was corrected for the ma trix (net weight) and MDC values were derived. All results were acceptable and meet the C H-WAC TRU/Non-TRU discrimination criterion of 100 nCi/g. Results are documented in A ppendix E-1 of the calibration report.

Reporting thresholds are required for the radionucl ides that are not measured directly; specifically 242 Pu, 234 U and 90 Sr. The 90 Sr reporting threshold is computed from the reporte d

137 Cs LLD using an activity ratio determined from SRS- CCP AK NDA memoranda. For SRS waste, the activity ratio is taken as 1 unless spec ified differently in appropriate AK

documentation. 234 U is derived from the measured 235 U and 238 U values or lack thereof by algorithm. Since this is not a function of scaling an individual radionuclide, SRS-CCP personnel stated that it is not technically feasible to deriv e a reporting threshold for 234 U. 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 BSGS aspect of the NABC.

BNAS LLD Determination

Nominal BNAS LLDs were determined from three replic ate counts of three container/matrix configurations without radioactive sources, using t he Performance Demonstration Program (PDP 2 ) Combustibles 55-gallon drum and cardboard matrice s for the SWB. The BNAS LLD that was determined during the initial NABC approval was not affected by this T1 change. Additional information regarding the BNAS LLD deter mination is documented in CCP-SRSSRBC001, see EPA Docket No. A-98-49; II-A4-114.

7.0 SUMMARY OF RESULTS AND CONCLUSIONS

There were no findings or concerns regarding the p erformance and documentation of performance testing for the gamma operational modes for the NABC resulting from this T1

evaluation.

2 PDP sources are constructed by Los Alamos National Laboratory for use in the CBFO-sponsored NDA Performance Demonstration Program.7

8.0 APPROVAL

During this T1 evaluation, the EPA evaluated the BS GS aspect of the NABC calibration range of

238 Pu and reduced 20-minute count time. Based on this T1 evaluation, the NABC is approved for the extension of the calibration range of the BSGS aspect of the NABC to 7.18 grams of 238 Pu utilizing a reduced 20-minute assay time. The NABC is approved to assaying CH TRU wastes in the gamma and neutron detection modes for two measu rement configurations—55-gallon drum

and SWBs—consistent with the limitations described in this report.