DOCKET NO: A-98-49; II-A4-177

WASTE CHARACTERIZATION TIER 1 CHANGE REPORT

EPA TIER 1 EVALUATION OF THE CENTRAL CHARACTERIZATION PROGRAM REMOTE-HANDLED TRANSURANIC WASTE CHARACTERIZATION P ROGRAM FOR THE SAVANNAH RIVER SITE: ADDITION OF WASTE STREAM SR-RH-221H.01

U.S. Environmental Protection Agency Office of Radiation and Indoor Air Center for Federal Regulations 1200 Pennsylvania Avenue, NW Washington, DC 20460

August 2013i TABLE OF CONTENTS Section Page Acronyms and Initializations ......................

................................................... ................................. ii

1.0 Introduction ......................................

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

2.0 Purpose of Tier 1 Evaluations .....................

................................................... ......................3

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

................................................... .........................3

4.0 Scope of the Tier 1 Evaluation.....................

................................................... .....................4

5.0 EPA Evaluation Personnel ..........................

................................................... ......................4

6.0 Radiological Characterization Technical Evaluation

................................................... ........4

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

................................................... .......................13

8.0 Conclusions .......................................

................................................... ..............................14

TABLES

Table 1. EPA Tier 1 Evaluation Team Members .......

................................................... .................. 4 Table 2. Dominant Waste Types for Containers in Was te Stream SR-RH-221H.01 ..................... 9

FIGURES

Figure 1. Radiological Characterization Flow Diagra m for Waste Stream SR-RH-221H.01 ........ 6 Figure 2. Scaling Factor Development for Waste Stre am SR-RH-221H.01 .................................. 7

ATTACHMENTS

Attachment A: Approval Summary for Savannah River S ite Remote-Handled Waste

Characterization Program Attachment B: List of Documents Reviewed by EPA dur ing T1 Evaluationii ACRONYMS AND INITIALIZATIONS

AK acceptable knowledge AKSR acceptable knowledge summary report

Am americium BDR batch data report

CBFO Carlsbad Field Office CCP Central Characterization Program CFR Code of Federal Regulations

CH contact-handled

Ci curie CIS Characterization Information Summary

Co cobalt CRR Characterization Reconciliation Report

Cs cesium DOE U.S. Department of Energy

DTC dose-to-curie EPA U.S. Environmental Protection Agency Eu europium

HS heat source ISOCS In Situ Object Counting System MCNP5 Monte Carlo N-Particle Transport Code RSICC C omputer Code

Collection, Oak Ridge National Laboratory

MCS Mobile Characterization Services MDA minimum detectable activity mR/hr/Ci milliroentgen per hour per curie mrem/hr millirem per hour NDA nondestructive assay Np neptunium Pu plutonium ORTEC Oak Ridge Technical Enterprise Corporation

RH remote-handled RTR real-time radiographyiii

SC&A S. Cohen and Associates (SC&A, Inc.) SCG summary category group SF scaling factor

Sr strontium

SRS Savannah River Site

T1 Tier 1

T2 Tier 2 TMU total measurement uncertainty

TRU transuranic

U uranium

WIPP Waste Isolation Pilot Plant

WSPF Waste Stream Profile Form1

1.0 INTRODUCTION

This report supports the U.S. Environmental Protect ion Agency’s (EPA’s) approval of a Tier 1 (T1) change to add Waste Stream SR-RH-221H.01 to th e approved characterization program at the U.S. Department of Energy’s (DOE’s) Savannah Ri ver Site (SRS). In April 2012, EPA approved the Central Characterization Program (CCP) 1 to characterize remote-handled (RH) waste at SRS. On May 30, 2013, the Carlsbad Field O ffice (CBFO) requested EPA’s approval of a T1 change to add Waste Stream SR-RH-221H.01. Usin g the EPA-approved waste characterization processes discussed in this report , SRS-CCP can characterize Waste Stream SR-RH-221H.01 for disposal at the Waste Isolation P ilot Plant (WIPP).

In accordance with Title 40 of the Code of Federal Regulations [40 CFR 194.8(b)], EPA conducted Baseline Inspection No. EPA-SRS-CCP-RH-08 .11-8 of the CCP waste characterization program at SRS on August 30–Septem ber 1 and December 6–7, 2011. The April 2012 SRS baseline final inspection report (see EPA Docket No. A-98-49; II-A4-161) documents EPA’s approval of the acceptable knowledge (AK) pro cess for RH transuranic (TRU) debris waste streams that have:

• Companion 2 contact-handled (CH) debris waste streams.

• A radiological characterization process that uses:

o Dose-to-curie (DTC),

o Scaling factors generated through use of the Mobile Characterization Services (MCS)/In Situ Object Counting System (ISOCS 3 ), and

o Historical assays of companion CH debris waste stre ams for assigning radionuclide values for RH waste.

• Real-time radiography (RTR) processes specific to S RS-CCP’s RH waste characterization program.

The companion CH waste stream for RH Waste Stream S R-RH-221H.01 is Waste Stream SR-W027-221H-HET. Because the AK and RTR processes have not changed since the baseline approval, EPA limited the scope of this T1 review t o the radiological characterization process. Waste Stream SR-RH-221H.01 is characterized by DTC, as described in CCP-RC-SRS-601, “Central Characterization Program Remote-Handled Tr ansuranic Radiological Characterization Technical Report for Savannah River Site Remote-Han dled Transuranic Debris Waste, Waste

1 The Central Characterization Program was formerly known as the Central Characterization Project, and both names are used in the documentation reviewed f or this evaluation.

2 A companion CH waste stream has the same summary c ategory group, same waste stream definition and same radiological and physical properties as the su bject RH waste stream. In this case, the only diffe rence between containers in the companion CH waste stream and tho se in the subject RH waste stream is the waste’s ex ternal dose rate, i.e., less than or greater than 200 millirem per hour (mrem/hr), which makes the waste CH or RH, respectively.

3 Unlike other nondestructive assay (NDA) instrument s in CH programs, the ISOCS is not a direct characterization method; it is used exclusively for obtaining the relative ratios of radionuclides, i. e., scaling factors. The ISOCS data had been confirmed by measurements d one on an approved CH NDA system.2

Stream: SR-RH-221H.01,” Revision 1, dated June 05, 2013. The scaling factors are determined using the MCS/ISOCS when measurement data are avail able or were based on selected CH NDA results from characterization of the companion CH W aste Stream SR-W027-221H-HET. These 15 drums of TRU waste are the subject of this T1 re port, but EPA’s approval also includes any additional drums that are added to Waste Stream SR- RH-221H.01 in the future, provided they are characterized using the same processes.

Because there were no new equipment or additional n ew processes on site at SRS as part of the T1 request, EPA conducted a desktop review of this change, concluding that the SRS-CCP plan to use the EPA-approved system of controls to chara cterize the 55-gallon containers of Waste Stream SR-RH-221H.01 is acceptable. EPA did not ide ntify any findings or concerns during this evaluation.

As a result of this evaluation, EPA did not make an y changes to the SRS-CCP RH T1 and Tier 2 (T2) designations that were established during the baseline approval and modified in February 2013 as presented in Table 1 of the report document ing EPA’s approval of the addition of Waste Stream SR-RH-235F.01 (See EPA Docket No: A-98-49; I I-A4-170).

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 website and by emails to the WIPPNEWS list, in accordance with 40 CFR 194.8(b)(3 ).3

2.0 PURPOSE OF TIER 1 EVALUATIONS

Certain changes to the waste characterization activ ities after the date of the site’s baseline inspection must be reported to and, if applicable, approved by EPA according to the tiering requirements set forth in 40 CFR 194.8 and incorpor ated into the SRS-CCP RH baseline final report (see EPA Docket No. A-98-49; II-A4-161).

Under the changes to 40 CFR 194.8 promulgated in th e July 16, 2004, Federal Register notice (Vol. 69, No. 136, pages 42571–42583), EPA must per form a single baseline inspection of a TRU waste generator site’s waste characterization p rogram. The purpose of EPA’s baseline inspection is to approve the site’s waste character ization program, based on the demonstration that the program’s components, with applicable cond itions and limitations, can adequately characterize TRU wastes and comply with the regulat ory requirements imposed on TRU wastes destined for disposal at the WIPP.

Following EPA’s baseline approval, EPA is authorize d to evaluate and approve changes, if necessary, to the site’s approved waste characteriz ation program by conducting additional inspections under the authority of 40 CFR 194.24(h) . Changes requiring EPA notification and approval prior to implementation (T1) and those req uiring post-implementation notification (T2) are identified in the site-specific baseline inspec tion reports. When evaluating proposed T1 changes for approval, EPA may conduct a site inspec tion to observe at first hand the implementation of the change or can decide to condu ct a desktop review of information provided specific to a change. DOE may choose to characteriz e and dispose of any previously approved TRU waste using processes, procedures or equipment implemented as T2 changes at risk of subsequent EPA disapproval. EPA reviews T2 changes on a quarterly basis and may conduct continued compliance inspections to evaluate implem ented T2 changes to verify adequacy. Attachment A lists all of EPA’s non-T2 approvals of the SRS-CCP RH TRU waste characterization program.

3.0 PURPOSE OF THIS REPORT

This report presents the results of EPA’s evaluatio n of a T1 change to add Waste Stream SR-RH221H.01 to SRS-CCP’s approved waste characterizatio n program. This report presents the technical basis for and results of EPA’s approval d ecision. EPA’s approval decision regarding the addition of Waste Stream SR-RH-221H.01 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 DOE documents that EPA reviewed for this evalua tion are cited in different sections throughout the report and are listed in Attachment B. Any of these documents can be requested from the following address:

Manager, National TRU Program Carlsbad Field Office U.S. Department of Energy P O Box 3090 Carlsbad, NM 88221-30904

4.0 SCOPE OF THE TIER 1 EVALUATION

The scope of EPA’s T1 evaluation is the radiologica l characterization approach used to characterize Waste Stream SR-RH-221H.01. Section 6. 0 of this report details the radiological characterization technical elements assessed during this evaluation.

5.0 EPA EVALUATION PERSONNEL

The EPA evaluation team members consisted of the pe rsonnel listed in Table 2 with their affiliations and functions. EPA relied primarily on reviews of documents and information provided by SRS-CCP. When additional information or clarifications were needed, EPA had discussions with Irene Joo, 4 the CCP RH Project Manager, who served as the poin t of contact for this T1 evaluation.

Table 1. EPA Tier 1 Evaluation Team Members

6.0 RADIOLOGICAL CHARACTERIZATION TECHNICAL EVALUATION

RH Waste Overview

Waste Stream SR-RH-221H.01 consists of RH TRU debri s wastes generated by radiochemical analytical laboratory and research activities condu cted in the H-Canyon facility at SRS from 1973 to 2007. This waste stream was originally incl uded in CH TRU Waste Stream SR-W027- 221H-HET, stored in 55-gallon drums and characteriz ed under a CH TRU program using NDA. However, 15 drums had surface dose rates exceeding the 200 mrem/hr limit for CH waste and, therefore, were assigned to RH TRU Waste Stream SR- RH-221H.01.

Documents, Waste Containers, and Batch Data Reports and Calculation Packages

EPA evaluated the SRS-CCP documentation that suppor ted radiological characterization of Waste Stream SR-RH-221H.01. SRS-CCP provided CCP-RC -SRS-601, Revision 1, to EPA as the main document for review. Attachment B lists al l documentation reviewed by EPA, including batch data reports (BDRs) and calculation packages.

Waste Characterization Element Description

EPA evaluated the radiological characterization of SRS-CCP RH Waste Stream SR-RH-221H.01 in terms of its technical adequacy, as supported by the program’s documents, procedures and controls, and the knowledge and understanding of th e personnel involved in the RH waste

4 Irene Joo was formerly known as Irene Quintana and both names are used in the documentation reviewed to support this evaluation.

Name Affiliation & Function Ed Feltcorn Lead Inspector, EPA Rose Gogliotti Technical Evaluator – Radiological C haracterization, SC&A Patrick Kelly Technical Evaluator – Radiological C haracterization, SC&A Amir Mobasheran Technical Evaluator – Radiological Characterization, SC&A5

characterization program. During this RH evaluation , the EPA team evaluated the following elements of the SRS-CCP radiological characterizati on program:

• Overall radiological characterization.

• ISOCS measurements made to determine scaling factor s.

• Derivation of radionuclide scaling factors using is otopic ratios from ISOCS assays.

• Derivation of scaling factors not based on ISOCS th rough isotopic distributions from historical assays of companion CH Waste Stream SR-W 027-221H-HET.

• Representativeness and technical adequacy of the an alytical data used to support the scaling factors.

• Development of two DTC correlations for 55-gallon d rums based on Monte Carlo N-Particle Transport Code (MCNP5) modeling of the d rum’s gamma dose rate at one meter from the surface of drum using a one-curie (C i) source of both americium-241 ( 241 Am) and neptunium-237 ( 237 Np), assumed to be the main contributors to the dos e.

• Uncertainty analysis.

Each of these is discussed in the sections that fol low.

Technical Evaluation

The EPA evaluation team evaluated the following asp ects:

(1) The overall radiological characterization process a nd its documentation were evaluated and found to be adequate.

The radiological characterization process for Waste Stream SR-RH-221H.01 uses DTC in conjunction with radionuclide-specific scaling fact ors developed from ISOCS measurements, a process that EPA approved at the SRS RH baseline. S RS-CCP scaled the measured and modeled radionuclide values to 241 Am, correlating a drum’s external exposure (dose) r ate and its contents of specific radionuclides. Development of the radio nuclide-specific scaling factors is the main technical aspect of SRS-CCP’s radiological characte rization. The SRS-CCP RH radiological characterization program incorporated five main asp ects:

• Development of 241 Am-based scaling factors for plutonium-239 ( 239 Pu), 240 Pu, 241 Pu,
242 Pu, 237 Np and cesium-137 ( 137 Cs) based on ISOCS measurements when detected.

• Historical information (AK) for CH Waste Stream SR- W027-221H-HET, as summarized in CCP-AK-SRS-600 5 and associated source documents.

• When radionuclides were not detected by ISOCS, deve lopment of scaling factors for
239 Pu, 240 Pu, 241 Pu, 242 Pu, uranium-233 ( 233 U), 234 U, 238 U, 137 Cs and strontium-90 ( 90 Sr)

5 “Central Characterization Program Acceptable Knowl edge Summary Report for Savannah River Site Remote-Handled Transuranic Waste, Waste Streams: SR -RH-221H.01 and SR-RH-221H.02,” CCP-AK-SRS-600, Revision 1, November 27, 2012.6

were based on past assays of the RH waste stream’s CH counterpart, Waste Stream SRW027-221H-HET, and assumptions about the waste’s or igins.

• Scaling factors for 238 Pu were based on CH data in all cases, as discussed in (2), below.

• MCNP5 modeling to determine the correlation between the amount of 241 Am and 237 Np in each drum and the drum’s dose rates at one meter

.

• Direct exposure rate measurements (DTC) of each was te drum.

The EPA inspection team prepared two flow diagrams to accurately reflect this process, shown in Figures 1 and 2 below. EPA determined that the r adiological characterization process for Waste Stream SR-RH-221H.01 was technically adequate and appropriately documented. Consistent with the T1 and T2 designations that wer e established during the baseline approval and modified in February 2013, any new RH waste str eam not approved to date or the addition of containers to Waste Stream SR-RH-221H.01 that requi res a different radiological characterization process from what is documented in CCP-RC-SRS-601 remains a T1 change. Similarly, any change to CCP-RC-SRS-601 that requir es CBFO approval remains a T2 change.

Figure 1. Radiological Characterization Flow Diagra m for Waste Stream SR-RH-221H.0 Source: Based on CCP-RC-SRS-601, Revision 1 Use MCNP5 to separately model the 1-meter dose rates based on a 1-Ci source of 241 Am and 237 Np

Develop the DTC conversion factors (mR/hr/Ci) as a function of the waste density for 241 Am and 237 Np

Execute DTC to derive the 241 Am activity in curies

Multiply the 241 Am activity by the SFs to determine activities of other radionuclides

Determine the uncertainties in radionuclide activities and massesDevelop drumspecific scaling factors (see Figure 2).7Figure 2. Scaling Factor Development for Waste Stream SR-RH-221H.01Source: Based on SRS-RH-67, Revision 1 (Reference U001)Use ISOCS to develop drum-specific241Am-based SFs for239Pu,240Pu,241Pu,242Pu,237Np and137CsUse241Am/237Np ratio todetermine if drum containsheat-source (238Pu-dominant)waste or a non-heat-source(237Np-dominant) wasteDecay correct241Am and241Pu. Thencalculate the SFs for238Pu,239Pu,240Pu,241Pu,242Pu137Cs and234U to241Am foreach assayCompile SFsunique to each“extraction”The geometric means of MDAs for233U,235U and238U were applied to CH dataIf detected:Sort CH database results into three“extractions’ based on the241Am/237Npratio-1stExtraction: 1.00E-2 ≤ SF ≤ 1.00E-1-2ndExtraction: 1.00E-1 ≤ SF ≤ 3.50E1-3rdExtraction: 1.00E3 ≤ SF ≤ 1.00E4Find the arithmeticmean of the SF foreach isotope withineach extractionUranium SFs Development:ISOCS Derived SFs:CH Database Derived SFs:Randomly select 20 assay results withoutpositive U values from the 1st, 2ndand 3rdextractions and calculate the geometricmean for U isotopesSort CH data into three groups(“extractions”) based on their ratios of241Am/237Np-1stExtraction: 1.00E-2 ≤ SF ≤ 1.00E-1-2ndExtraction: 1.00E-1 ≤ SF ≤ 3.50E1-3rdExtraction: 1.00E3 ≤ SF ≤ 1.00E48

(2) Use of the In Situ Object Counting System to derive isotopic ratios (scaling factors) was found to be correctly implemented and appropriately documented.

EPA previously approved an ISOCS instrument to assa y WIPP-bound RH TRU waste drums at the SRS RH baseline during 2011 (see EPA Docket No. A-98-49; II-A4-161). During the SRS RH baseline, EPA approved the use of scaling factor s relative to 241 Am for 239 Pu, 240 Pu and
241 Pu, and subsequently approved the use of the ISOCS for any gamma-emitting radionuclide (see EPA Docket No. A-98-49; II-A4-170), including 238 Pu. However, the characterization of these wastes was completed prior to EPA’s subsequen t expanded approval of the use of ISOCS, and SRS-CCP relied exclusively on CH data to develo p scaling factors for 238 Pu.

For RH Waste Stream SR-RH-221H.01, SRS-CCP used ISO CS measurements to scale TRU radionuclides to 241 Am. It also scaled 242 Pu, 237 Np and 137 Cs to 241 Am when they were detected in levels above the minimum detectable activity (MDA). 242 Pu and 237 Np are not WIPP-tracked radionuclides but SRS-CCP must report their contrib ution to comply with shipping requirements for any radionuclide that contributes significantly to the radiological hazard of the drum. 137 Cs is a WIPP-tracked radionuclide with a strong gamma emi ssion that is easy to detect. Each of the 15 RH drums was assayed by the ISOCS; the results are shown in Table 3-1 of CCP-RC-SRS-601, Revision 1.

If ISOCS detected a radionuclide it was scaled to 241 Am. Scaling factors generated from ISOCS results are listed in Table 3-2 of CCP-RC-SRS-601, Revision 1. If ISOCS did not detect a radionuclide, SRS-CCP used historical CH assays to generate scaling factors [see Item (3) below].

Additionally, SRS-CCP used ISOCS results to identif y the origin of each drum. The AK summary report indicates that waste from CH Waste S tream SR-W027-221H-HET came from two major activities: (1) 238 Pu heat source (HS) fabrication and (2) 237 Np target fabrication (target). Based on what is known about these proces ses, waste from 237 Np target fabrication would be expected to have a low 241 Am/ 237 Np ratio, while HS material would be expected to have a ratio as large as 1,000 to several thousands . Because 239 Pu was not detected in 13 drums (Nos. SR570545, SR526227, SR570548, SR513955, SR526 263, SR570546, SR570547, SR526225, SR526226, SR526264, SR522989, SR526224 an d SR513961), they can be classified as originating from 237 Np target production; they have 241 Am/ 237 Np ratios ranging from 2.59E-02 to 3.46E+01. The remaining three drums (Nos. SR5035 13, SR522331 and SR545535) have
241 Am/ 237 Np ratios ranging from 1.12E+03 to 4.45E+03, and th ese drums can be classified as originating from HS fabrication. These categories a re used to better characterize scaling factors obtained through the use of historical CH data.

(3) Use of nondestructive assay data from contact-handl ed Waste Stream SR-W027-221HHET to develop scaling factors for uranium isotopes , unmeasured plutonium isotopes and fission products, including cesium, was found to be technically adequate and correctly documented.

SRS Waste Stream SR-W027-221H-HET is the CH equival ent of RH Waste Stream SR-RH221H.01, and all 15 of the 55-gallon RH drums in Wa ste Stream SR-RH-221H.01 were9

originally generated and managed as CH waste. They fell out of the waste stream when the drum’s contact dose readings exceeded the contact d ose rate limit for CH of 200 mrem/hr. As such, these RH drums are assumed to have the same r atios of radionuclides as the CH drums generated from the same two dominant processes (HS and target fabrications), as stated in Item (2) above. This assumption is the basis for using h istorical CH assays to derive the ratios of Pu, U and fission products to 241 Am for the RH drums.

Approximately 2,900 CH assay records from Waste Str eam SR-W027-221H-HET were available at the time CCP-AK-SRS-601 was completed. SRS-CCP s elected two subsets (“First Extraction and Second Extraction”) of assays to represent wast es generated from target fabrication and one subset (“Third Extraction”) to represent waste gene rated from HS production. The 241 Am/ 237 Np ratios from the CH assays were used to identify dru ms most similar to the 15 RH drums. SRSCCP selected CH drums that had ratios ranging from 0.01 to 0.1 as belonging to the First Extraction and CH drums that had ratios ranging fro m 0.1 to 35 as belonging to the Second Extraction representing target material. Drums with ratios ranging from 1,000 to 10,000 represented HS materials. This selection process re sulted in three CH drums for the First Extraction and 71 CH drums for the Second Extractio n representing target waste and 91 CH drums representing HS materials. SRS-CCP chose to u se these three subsets of CH Waste Stream SR-W027-221H-HET (a total of 165 CH drums) o n the assumption that they would most accurately reflect the distribution of radionuclide s in the 15 drums in Waste Stream SR-RH221H.01. All 165 extracted assays were corrected fo r decay and in-growth from their assay date to May 15, 2012, to better reflect the current cont ents of the drums. Table 3 below shows the dominant waste type for each of the 15 drums in Was te Stream SR-RH-221H.01. Due to the complexities of the waste, each radionuclide scalin g factor was calculated separately. The 241 Am scaling factors are summarized in Table 3-6 of CCP- RC-SRS-601, Revision 1.

Table 2. Dominant Waste Types for Containers in Was te Stream SR-RH-221H.01

Container Dominant Waste* SR570545 Np Target SR526227 Np Target SR570548 Np Target SR513955 Np Target SR526263 Np Target SR570546 Np Target SR570547 Np Target SR526225 Np Target SR526226 Np Target SR526264 Np Target SR522989 Np Target SR526224 Np Target SR513961 Np Target SR522331 HS SR545535 HS

* Target dominant waste had 241 Am/ 237 Np ratios from 0.01 to 3.5 and HS dominant waste ha d 241 Am/ 237 Np ratios from 1,000 to 10,000 Source: Based on SRS-RH-67, Revision 1 (Reference U 001).10

Uranium Isotopes (excluding 234 U)

SRS-CCP expected U in trace quantities in this wast e stream because of the nature of the wasteproducing processes. Higher concentrations would ha ve been detected by ISOCS measurements. Less than 10% of the CH assays in Waste Stream SR-W 027-221H-HET had positive U values. To develop the scaling factors for 233 U, 235 U and 238 U, SRS-CCP randomly selected 20 MDA values from the CH drum assays representing target materials and 20 MDA values from the CH drum assays representing HS materials and pooled th ese into a set of 40 MDAs for each isotope. The MDA values of 235 U, 233 U and 238 U in each of these 40 drums were divided by that dr um’s decay

- corrected 241 Am value. When an assay did not have detectable lev els of a radionuclide, the average MDA for that radionuclide was applied to th at sample. Although an MDA does not represent a drum’s true radionuclide concentration, its use allows an upper-end estimate of the drum’s content. The use of this value eliminates un derestimation of true averages due to the measurement system’s limitations. For the 40-drum s ubset, drum-specific scaling factors for each isotope were then averaged geometrically to pr oduce 241 Am-based scaling factors for 235 U,
233 U and 238 U. These averaged MDA scaling factors were then app lied to every non-measured corresponding U isotope in the 165-drum subset (the 3-drum and 71-drum subsets representing target material plus the 91-drum subset representin g HS material). The 165-drum subset was then arithmetically averaged per isotope to develop a se t of 241 Am-based U scaling factors.

Plutonium Isotopes, 234 U and 137 Cs

When Pu isotopes (excluding 238 Pu) and/or 137 Cs were not detected above the MDA on the ISOCS assay, CH data were used to bound the content s of a drum. HS and target scaling factors are generated differently for the Pu isotopes, 234 U and 137 Cs. The SFs for 238 Pu were determined using CH data in all cases, irrespective of ISOCS r esults. Each is discussed below.

Heat Source Scaling Factors

After performing decay corrections for 241 Am and 241 Pu, the arithmetic mean of all 241 Am-based scaling factors for each radionuclide in the 91-dru m subset (Third Extraction) of the CH waste stream was calculated. Drums without reported value s for any specific radionuclide were treated as blanks rather than zeros in averaging. This prov ides a conservative bounding of the drum’s radionuclide contents.

Neptunium Target Scaling Factors

After performing decay corrections for 241 Am and 241 Pu, the arithmetic mean of all 241 Am-based scaling factors for each radionuclide in the 3-drum subset (First Extraction) and in the 71-drum subset (Second Extraction) was calculated. Drums wi thout reported values for any specific radionuclide were treated as blanks rather than zer os in averaging. This provides a conservative bounding of the drum’s radionuclide contents.

Strontium-90

The NDA system does not directly measure the beta-e mitting radionuclide 90 Sr; its contribution is inferred by assuming essentially a one-to-one ra tio with 137 Cs. This is a common practice in11

determining RH scaling factors because both radionu clides are fission products with comparable fission yields.

(4) Computer modeling to develop the dose-to-curie corr elation was evaluated and was found to be adequate.

SRS-CCP used MCNP5 to develop the DTC correlation f or a 55-gallon drum filled with debris in conjunction with its external dose rate at one m eter. The modeling was based on the assumption that: either a one-Ci source of 241 Am or a one-Ci source of 237 Np (just one source in each model) was uniformly distributed within the dr um; the only significant gamma emitters

were 241 Am and 237 Np; and contributions of europium-154 ( 154 Eu), cobalt-60 ( 60 Co) or other gamma emitters were negligible. Using the scaling f actor for 237 Np, waste density and DTC correlations, and dose partitioning allows calculat ion of the dose and activity attributable to
241 Am. The 241 Am activity is then used with the 241 Am-based scaling factors to determine the activities of the other TRU radionuclides of intere st. Each drum’s MCNP5 results are documented in calculation package SRS-RH-53 (Refere nce U015).

Consistent with the T1 and T2 designations that wer e established during the baseline approval and modified in February 2013, the use of any metho d to determine scaling factors other than those documented in CCP-RC-SRS-601 remains a T1 cha nge.
(5) Execution and documentation of the dose-to-curie te chnique was assessed and found to be adequate.

EPA observed the DTC technique on August 30, 2011, in the DTC alcove located in Area E, Pad 4, as part of the RH baseline inspection at SRS . Consistent with the T1 and T2 designations that were established during the baseline approval and modified in February 2013, the use of any alternate radiological characterization procedure o ther than DTC with procedure CCP-TP-504 6 in conjunction with scaling factors documented in CCP- RC-SRS-601, or substantive modification thereof, remains a T1 change.

(6) Radionuclide documentation in the dose-to-curie bat ch data report was assessed and found to be adequate.

The DTC results for all 15 containers were document ed in BDR Nos. SRSRHDTC11003, SRSRHDTC12001, SRSRHDTC12002 and SRSRHDTC12003. For logistical reasons, some containers had Waste Container Dose-to-Curie Conver sion Records that had been superseded. All containers used the initial DTC measurement eve nt served as the basis for the radionuclide calculations, often in conjunction with more recent ly derived radionuclide scaling factors. The EPA inspection team verified that each BDR included the following:

• Site Project Manager checklist, CCP-TP-504, Revisio n 13, Attachment 8.

• BDR cover sheet, CCP-TP-504, Revision 13, Attachmen t 4.

6 CCP-TP-504, CCP Dose-to-Curie Survey Procedure for Remote-Handled Transuranic Waste, Revision 13, September 17, 2012.12

• BDR table of contents, CCP-TP-504, Revision 13, Att achment 5.

• BDR narrative summary, CCP-TP-504, Revision 13, Att achment 6.

• Independent Technical Reviewer checklist, CCP-TP-50 4, Revision 13, Attachment 7.

• Measurement control report with all parameters acce ptable.

• Container data sheets, CCP-TP-504, Revision 13, Att achment 2.

• Concentrations and corresponding uncertainties for all WIPP-tracked radionuclides.

• Waste Container Dose-to-Curie Conversion Records do cumenting: revision of spreadsheet indicating the use of correct radionucl ide scaling factors; container weights; waste stream number; and TRU determination.

• Evidence of signatures by the Independent Technical Reviewer and a Site Project Manager on CCP-TP-504, Revision 13, Attachments 7 a nd 8.

• Correct revision of CCP-TP-504 (Revision 13).

EPA noted large uncertainties associated with some containers, i.e., containers where the uncertainty exceeded the activity (or mass) value. This was observed in containers whose scaling factor determinations relied primarily on CH data a s opposed to direct ISOCS measurements. There are three sub-populations in the CH database and each population has a unique set of scaling factor uncertainties that, when incorporate d, yield high overall uncertainty values for the container. EPA noted a minor error regarding the in corporation of 237 Np in the calculations for TRU Alpha Activity Concentration and its uncertaint y, which SRS-CCP acknowledged.

CCP-RC-SRS-601, Revision 1, presents radionuclide s caling factors and other data for container No. SR503513. However, SRS-CCP determined that this container was not RH by virtue of a measured external dose-rate less than 200 mrem/hr, as documented in SRSRHDTC12003, NCRRHSRS-0607-13. This container does not meet the def inition of RH waste and was removed from DTC BDR SRSRHDTC12003, as discussed below.

The four BDRs were technically adequate.

(7) Remote-handled determinations were evaluated and fo und to be adequate.

SRS personnel measured contact dose rates, and SRS- CCP provided the dose rate survey sheets for all 15 drums of Waste Stream SR-RH-221H.01. EPA reviewed the records, which indicated gamma-only dose readings at a distance of five cent imeters for all 15 drums listed in CCP-RCSRS-601, Revision 1, Table 3-1. The values indicate d that all 15 drums had contact dose reading clearly in excess of 200 mrem/hr, i.e., all drums w ere clearly RH. As noted above, container No. SR503513 is documented in CCP-RC-SRS-601, although SRS-CCP did not provide a dose rate survey sheet for this container. Based on SRSRHDTC1 2003, the container does not meet the definition of RH waste by virtue of a measured exte rnal dose-rate less than 200 mrem/hr, as documented in NCR-RHSRS-0607-13.13

(8) Transuranic determinations were evaluated and were found to be adequate.

DTC BDRs Nos. SRSRHDTC11003, SRSRHDTC12001, SRSRHDT C12002 and SRSRHDTC12003 contained activity and mass values wi th the associated uncertainties for the 10 WIPP-tracked radionuclides plus other radionucli des, as appropriate. In all cases, the TRU alpha concentration exceeded 100 nanocuries per gra m.
(9) The technical basis and documentation of total meas urement uncertainty were evaluated and found to be adequate.

The development of total measurement uncertainty (T MU) for Waste Stream SR-RH-221H.01 is based on the propagation of uncertainties present i n the determination of the waste stream’s radiological constituents. These aspects are assume d to be independent, which allows them to be added in quadrature. 7 The TMU determination included contributions of th e following:

• 241 Am DTC correlation—uncertainties due to MCNP5® code , waste mass and source distribution within drum, and waste density.

• 241 Am activity measurement—dose rate measurement uncer tainty and uncertainty due to the contribution of other gamma-emitting radionucli des.

• Scaling factor uncertainty—ISOCS-derived scaling fa ctor uncertainties, waste density uncertainties and CH-derived scaling factor uncerta inties.

A general treatment of TMU for Waste Stream SR-RH-2 21H.01 is presented in CCP-RC-SRS601, Section 5, and the detailed treatment of TMU i s provided in “Uncertainty Analysis for SRRH-221H.01,” calculation package SRS-RH-70 (Referen ce U004). The overall uncertainties are consistent with what EPA has observed for RH determ inations at other RH TRU generator sites. TMU varies slightly from drum to drum because scali ng factors are developed on an individual drum basis. Table 5-4 of CCP-RC-SRS-601, Revision 1 , provides an example of the TMU calculation for Drum No. SR570545.

7.0 FINDINGS AND CONCERNS

The EPA inspection team did not identify any findin gs or concerns relative to the addition of Waste Stream SR-RH-221H.01 during this T1 change ev aluation. There are no open issues relative to this T1 evaluation.

7 Adding in quadrature is a standard statistical tec hnique that allows one to combine the square root o f the sum of each contributor to uncertainty squared, res ulting in a lower value than what would be obtained if the values were simply added. For example, the TMU for 239 Pu is derived by taking the square root of (25.0%) 2 plus (10.0%) 2 plus (10.0%) 2 plus (100.0%) 2 plus (6.6%) 2 plus (26.0%) 2 , which equals 107.4%, which is less than the value obtained by simply summing the individual uncertain ty values (i.e., 177.6%, as shown in CCP Calculatio n Package: Uncertainty Analysis for SR-RH-221H.01, SRS-RH-70).14

8.0 CONCLUSIONS

Changes to Tiering

As a result of this evaluation, EPA did not make an y changes to the SRS-CCP RH T1 and T2 designations that were established during the basel ine approval and modified in the February 2013 T1 approval (Docket No: A-98-49; II-A4-170).

Approval

This T1 change consisted of the radiological charac terization process to characterize SRS Waste Stream SR-RH-221H.01 using DTC and scaling factors based on MCS/ISOCS and historical assays of the companion CH debris waste stream (see footnote 1) for assigning radionuclide values. Based on the results of this evaluation, EP A approves this T1 change consistent with the limitations specified in this report. EPA’s approva l addresses the 15 drums of TRU waste that are the subject of this T1 report. However, this approv al also includes any additional drums that are added to Waste Stream SR-RH-221H.01 in the future, provided they are characterized using the
same processes.A-1 ATTACHMENT A

APPROVAL SUMMARY FOR SAVANNAH RIVER SITE REMOTE-HAN DLED

WASTE CHARACTERIZATION PROGRAM

Approved Activity EPA Inspection Number, Approval Dates EPA Docket Number

SRS RH Baseline Approval EPA-SRS-CCP-RH-08.11-8, April 2012 A-98-49; II-A4-161

T1 Change – Addition of Waste Stream SR-RH-235F.01 February 11, 2013 A-98-49; II-A4-170B-1 ATTACHMENT B

LIST OF DOCUMENTS REVIEWED BY EPA DURING THE T1 EVA LUATION

CCP-AK-SRS-600, Central Characterization Program Ac ceptable Knowledge Summary Report for Savannah River Site Remote-Handled Transuranic Waste, Waste Streams: SR-RH-221H.01 and SR-RH-221H.02, Revision 1, November 27, 2012

CCP-AK-SRS-601, Central Characterization Program Re mote-Handled Transuranic Radiological Characterization Technical Report for Savannah River Site Remote-Handled Transuranic Debris Waste, Waste Stream: SR-RH-221H. 01, Revision 1, June 5, 2013

CCP-CP-SRS-602, Central Characterization Program RH TRU Waste Certification Plan for 40 CFR Part 194 Compliance for Savannah River Site Was te Stream: SR-RH-221H.01, Revision 0, April 16, 2013

CCP-TP-005, Revision 24, CCP Acceptable Knowledge D ocumentation, Attachment 15 – CCP TRU Waste Correlation and Surrogate Form, SR-RH-221 H.01, November 5, 2012

CCP-TP-504, Dose-to-Curie Survey Procedure for Remo te-Handled Transuranic Waste, Revision 13, September 17, 2012

Radiological Survey Reports for Drum Nos. SR570545, SR526227, SR570548, SR513955, SR526263, SR570546, SR570547, SR526225, SR526226, S R526264, SR522989, SR526224, SR513961, SR522331 and SR545535, dates ranging June 28, 2007–June 26, 2012

U001, CCP Calculation Package: Determination of the Scaling Factors for SRS-600, D. Ott, SRS-RH-67, Revision 1, June 27, 2013

U002, CCP Calculation Package: Determination of Rep ortable Radionuclides, D. Ott, SRS-RH68, Revision 0, November 19, 2012

U003, CCP Calculation Package: DTC and Related Calc ulations for SR-RH-221H.01, D. Ott, SRS-RH-69, Revision 1, June 20, 2013

U004, CCP Calculation Package: Uncertainty Analysis for SR-RH-221H.01, D. Ott, SRS-RH70, Revision 1, May 20, 2013

U015, CCP Calculation Package: DTC Modeling and Sen sitivity Studies for SRS RH Debris Waste, D. Ott, SRS-RH-53, Revision 0, September 9, 2012

Dose-to-Curie BDR Nos. SRSRHDTC11003, SRSRHDTC12001 , SRSRHDTC12002 and SRSRHDTC12003