LIC-18-0023, FC-18-009, Rev 0, Use of In-Situ Gamma Spectroscopy for Characterization (Reference 12)

FC-18-009, Rev 0, Use of In-Situ Gamma Spectroscopy for Characterization (Reference 12)

ML18215A225
Person / Time
Site:	Fort Calhoun
Issue date:	06/07/2018
From:	Brehm D M Omaha Public Power District
To:	Office of Nuclear Material Safety and Safeguards
References
LIC-18-0023 FC-18-009, Rev 0
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Text

FC-18-009 Revision 0 Page 1 of 25 Use of ln-Situ Gamma Spectroscopy for Characterization Prepared By: DM Brehm 6/7/2018 Reviewed By: AKBarker 0~ Date 6/18/2018 Date Approved By:

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009

1.0 INTRODUCTION

Revision 0 Page 2 of 25 The purpose of this document is to describe the use of in situ gamma spectroscopy for performing scoping, characterization, and final status surveys in support of characterization and License Termination.

Use of in situ gamma spectroscopy for unrestricted release of materials and equipment is not addressed in this document.

ISOCS have been used for characterization and Final Status Survey (FSS) measurements at Rancho Seco, Yankee Rowe and Maine Yankee. ISOCS has also been used for decommissioning characterization at Brookhaven National Laboratory.

[5] This document uses information from these previously NRC approved technical basis documents and the Brookhaven experience. The source documents for the information presented are referenced throughout this document.

This document applies to use of a Canberra characterized HPGe detector coupled to an MCA using Canberra Genie software for performing gamma spectrum analyses of various media. Acquisition of a characterized detector allows the use of the geometry composer software to modei actual survey unit conditions in order to obtain accurate gamma survey results. Use of the geometry composer also allows the determination of investigation criteria which will identify the possible presence of an elevated area of residual activity within the detector field of view exceeding the elevated measurement criteria value for the survey medium. 2.0 BACKGROUND Technical guidance contained within NUREG-1575, " Multi-Agency Radiation and Site lnvestigation Manual" (MARSSIM) regarding the conduct of radiation surveys and site investigations has generic application, and has the potential for use in any situation involving radioactive contamination, whether or nota release criterion is to be applied. The Data Quality Objective (DQO) process is the basis for the performance-based guidance in planning MARSSIM surveys. Because the MARSSIM emphasizes the use of statistical planning and data analysis for demonstrating compliance with a final status survey , there are few e x amples of how to apply the DQO process for other types of surveys where such formai analyses are not necessary, or even appropriate.

For example, data are collected during scoping surveys to confirm absence of licensed material in non-impacted areas or in characterization surveys in order to determine the extent , but not necessarily the amount, of contamination.

This does not mean that the data do not meet the objectives of compliance demonstration, but it may mean that formai statistical tests would be of little or no value because the data have not been collected for that purpose. However , ali analytical dat a should be of a quality , demonstrable through the DQO process, to support the determination or decision needed. Large areas or volumes can be assayed using ISOCS with a large field of view to reduce errors arising from non-homogeneity , providing a more accurate estimate of average radionuclide concentrations.

These advantages make in situ spectroscopy an attractive tool for many characterization applications.

The battery operated, field deploy a bl e g a mm a sp ec trom e t e r provid e s tr a dition a l spectra of c ounts as a function of

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009

.....---....,. Omahl Pub li c Powe r Distril:I Revision 0 Page 3 of 25 gamma energy. The spectra are then converted to rad i onuclide concentration by applying innovative efficiency calculations using Monte Carlo statistical methods and pre-defined geometry templates in the analysis software.

ln situ gamma spectroscopy has been effectively employed to perform final surveys at MDCs comparable to those typically achieved with hand-he l d i nstruments w i thout the possibility of failing to detect an area of elevated activity greater than the ele v ated measurement criteria value. ln situ gamma spectroscopy can be used for any situation in which the contaminant is a gamma emitter and the source geometry can be defined by the geometry composer.

Canberra has developed a HPGe detector which has been e x posed to gamma sources at multiple points in space in order to determine the detector response to gamma photons which interact with the detector and which or i ginate from any location about the detector.

The software uses an iterative discrete ordinate attenuation computation routine to predict the detector response w hen particular geometry features such as source to detector distances , shielding materials, thickness of source or shield materials , source and shield densities , source to detector angles , and source configurations are entered into the geometry composer. These features allow the same spectrum to be analyzed using more than one ge o metry. It is this capabilit y w hich makes possible the identification and evaluation of hot spots us i ng the investigation criterion. Validation of the ISOCS efficiency calibration software is be y ond the scope of this report. Canberra lndustries has performed e x tensive testing and validation on both the MCNP-based detector characterization process and the ISOCS cal i bration algorithms used by the software.

The full MCNP method has been sho w n to be accurate to w i thin 5% (typically).

ISOCS results have been compared to both full MCNP and to 119 different radioactive calibration sources. ln general , ISOCS is accurate to within 4-5% at high energies and 7-11 % for low energies. 3.0 DEFINITIONS 3.1 lnvestigation criterion-An activity limit at which further e v a l uation of the survey data is required for a MARSSIM Class 1 survey area. The in v estigation criterion is typically set at a value that ensures that the Derived Concentr a tion Guideline Level (DGCL) for the elevated measurement criteria (DCGLE M c) will not be e x ceeded. 3.2 ISOCS -ln Situ Object Counting System 3.3 World-Wide Fallout -The descent and deposition of radioacti v e ma t erial in the atmosphere onto the earth follo w ing a nuclear e x plosion, i nciden t, or accident.

4.0 CALCULATIONS AND EVALUATIONS 4.1 ISOCS Scoping , Characterization, and Final Status Surve y s of Soils and Concrete Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 4 of 25 The purpose of using ISOCS for soils and concrete characterization is to determine if the material is impacted (e.g., contaminated) and to evaluate the gamma emitting radionuclide concentrations.

ISOCs may also be used for other purposes such as unrestricted release of components , materials, soils or concrete or for reuse of concrete or soil as " clean" till in accordance with MARSAME. The gamma emitting radionuclides of concern for FCS Unit 1 have been identified in FCS FC-18-002.

The current list of radionuclides of concern are shown in Error! Reference source not found .. Table1 -lnitial Suite of Potential Radionuclides for the Decommissioning of FCS Radionuclide Half Life (years) H-3 12.3 Fe-55 2.73 Co-60 5.27 Ni-63 100.1 Sr-90 28.74 Cs-134 2.07 Cs-137 30.04 Pu-238 87.7 Pu-239/240 24,110 Pu-241 14.35 Am-241 432.2 Cm-243/244 29.1 Gamma emitting radionuclides such as Nb-94 , Eu-152 , Eu-154 and Am-241 do not make up significant percentages of the typical waste stream radionuclide mix and are likely to be limited in abundance.

Cs-137 however has a long half-life , is readily detectable by gamma spectroscopy , and comprises a significant fraction of most waste streams. Eu-152 and Eu-154 are present in activated concrete.

ldentification of Cs-137 can be used to screen soils and concrete.

This technical position can only be met using a characterized detector with geometry composer software using approved procedures unless geometry-specific, NIST-traceable calibration sources equal to the size of the detector field of view for each media are obtained.

The FCS ISOCS are HPGe detectors with a 50% relative efficiency.

A description and documentation of the characterization of the Canberra FCS HPGe detector (Modei GX5020) is documented in Reference

8. It is anticipated that final surveys will typically be performed with the detector at a distance of 1, 2, and 3 meters from the source with the 90 degree collimator installed.

These geometries have detector fields of view of 3 m 2 , 12 m 2 and 28 m 2 respectively.

Due to the critical relationship of the geometries to the analytical results , only approved geometries will be used for FSS surveys. The gamma spectroscopy analysis report provides the total activity detected within the field of view of the detector and reports them in units of pCi/g , pCi/m 2 or dpm/m 2. For spectra collected using the 90 degree collimator, the field of view is the source to Use of ln-Situ Gamma Spectroscopy for Character i zation FC-18-009 Revision 0 Page 5 of 25 detector distance (which is equal to the radius of the field of view) squared and multiplied by pi (re). For ISOCS Final Status Survey scoping and characterization surveys concrete source activity depths will typically be set at 2 cm to 5 cm. Location or Building specific concrete activity depths may be set at other depths based upon concrete core or other characterization data. Soil source activity depths will typically be set at 15 cm. These values are consistent with site characterization experience and NUREG-1575 assumptions. These source geometries allow for the collection of spectra with MDA values for the nuclides of interest (e.g., Cs-137 and Co-60) at less than or equal to 0.3 pCi/g for soil and less than 500 to 1 , 500 dpm/100 cm 2 for concrete. The NUREG-1757 Appendix H screening DCGLs can be used in lieu of site specific DCGLs that may be developed for soils and structures.

Since the 40% relative efficient ISOCS MDA values are three percent or less of the Cs-137 NUREG-1757 screening DCGLs for soils and structure surfaces, the chances of making a Type 1 error were less than 0.05 for reasonable count times of 20 to 60 minutes. The 50% relative efficient count times to reach similar MDAs are antic i pated to be 10 to 20 minutes. The "count to MDA" feature of the Canberra software will be employed as necessary to ensure that the desired MDAs are achieved. The following investigation criteria will be used for ISOCS scoping and characterization surveys of non-impacted soils and concrete.

• Detection of plant derived gamma emitting radionuclides of concern other than Cs-137 provide immediate indication that the material may be impacted by licensed radionuclides and should result in follow-up investigations and surveys in accordance with the characterization survey package.

• Detection of Cs-137 in concrete designated as non-impacted should also require additional investigative surveys and sampling in accordance with the characterization survey package.

• It is anticipated that some soils will contain readily detectable Ievels of Cs-137 from nuclear weapons testing fallout. Detection of Cs-137 in non-impacted soils that e x ceed the identified DGCLs for disturbed , undisturbed, drainage , and drainage soils should require additional investigative surveys and sampling in accordance with the characterization survey package. For ISOCS surveys of MARSSIM Class 1 areas requiring a DCGLE M C , the determination of the lnvestigation Criteria is based on taking a series of measurements using the detector in a standard geometry , such asa disk, located at a defined distance from the detector. The required geometry parameters are entered into the geometry composer and the acquired spectra are analyzed using the standard geometry. A new geometry is then developed which reduces the source to an area of 1 m 2 located at the periphery of the detector field of view. The original spectra are then re-analyzed using the new , small source area geometry. The ratio of the fui! field of view activity to the small source activity is determined and the ratio is multiplied by the DCGL EMC for a 1 m 2 area which becomes the lnvestigation Criterion.

Any in situ Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 6 of 25 measurement which equals or exceeds the lnvestigation Criterion , whe n analyzed using the full field of v iew geometry, requires further evaluation to rule out the possibility of a small elevated area of activity within the detector field of v iew. E va luations of the DCGLE MC for ISOCS detectors ha ve been performed at Rancho Seco [2], Yankee Rowe [3] and Maine Yankee. [4]. This information is presented in the following sections.

4.2 ISOCS Field of View and Detection Sensitivity and DCGL EMC 4.2.1 Soils Soils have been surveyed using in situ gamma spectroscopy with a geometry that evaluates soil activity to a depth of 15 cm over the detector field of view. With respect to Class 1 Survey Units , a surveillance for elevated activity is performed via scan surveys using hand-held field instruments. Acceptance criteria (DCGLEMc) is derived by multiplying the DCGL w by the area factor associated with that area bounded by the grid used to locate samples for direct measurements. Class 2 or Class 3 area survey designs do not employ elevated measurement comparisons, associated investigation Ievels are based on positive indications of licensed radioacti vity above the DCGL w or above background.

Occasionally, due to either background radioactivity or the size of t he sample location grid, the detection sensitivity for these hand-h e ld instr uments exceeds the DCGL EMC. ln such instances , the survey grid is reduced so that area factors yie lding higher DCGL EMC values can be used. This approach has a side effect of additiona l sampling, which impacts project schedules and costs. Additional samp lin g is further experienced to distinguish between n a tural radioa c ti vi ty and plant-derived radioactivity to investigate elevated instrument responses. When an investigation Ievel is encountered an investig ation is conducted, which may include the use of h a nd-held field instruments and soil sampling.

lnvestigation Criteria are established to ensure the DCGLE MC will not go und etec ted in a small elevated area at the e dge of the field of view. B eca use the detector's field-of-view i s greater than one-square-meter, it is as sumed that the (potential) one-square-meter of elevated radioa ct ivity is situated at the edge of the area being evaluate d. To compensate for reduced detection efficiencies associated with this assumption , an offset geometry adjustment factor is developed. Before the offset geometry adjustment fac to r can be developed , the detector's field-of-view must be determined based on the detector co nfiguration (e.g. collimator , detector height above the surface to be eval uated, etc.). At Yankee Row e , the detector was configured with a 90-degre e collimator and the detector was positioned at 2 meters from the surface to be evaluated.

This wo uld normall y have a 12 m 2 field of view bas ed upon a circle radius of 2 meters.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Figure 1 -90 Degree Collimator Field of View Revision 0 Page 7 of 25 At Yankee Rowe [3], the detector's field of-view was empirically determined using a series of measurements made at various off-sets relative to the center of the reference plane. The source used for these measurements was a 1.2 µCi Co-60 point-source with a physical size of approximately 1 cm 3. Each spectrum was analyzed as a point source both with and without background subtract.

It was observed that the detector responded quite well to the point source. Figure 2 presents the results with background subtraction applied. Nate that there was a good correlation with the expected nominal activity and that outside the 2-meter radius of the "working" field-of-view (e.g., at 90 inches , 2.286 meters) some detector response occurs. This validates that the correct attenuation factors are applied to the algorithms used to compute the efficiency calibration.

It also demonstrated that the actual field of view is greater than the 2 meter radius assumed at a 2 meter stand-off distance.

Use o f ln-Situ Gamma Spectroscopy for Characterization F C-1 8-009 Revision 0 Page 8 of 25 Figure 2 -Yankee Rowe Point Source Test Background Subtracted c *-;:;i,, *.;:: (.) <( 0 '° j 0 u 2 :-' 1.5 u 1 ::::, .._... 0.5 0 0 POINT SOURCE TEST (background subtracted) 18 48 60 66 72 Offset (inches) 78 84 90 Figure 3 shows the effect of plant-derived materials present in the reference background , which indicates an increasing over-response the further the point source is moved off center. Oetector response outs i de the assumed 2-m eter field-of-view would yie ld conservative results. Normally , source term adjacent to the survey units shou ld be r educed to e limin ate background interference.

Figure 3 -Yankee Rowe Point Source Test Background Not Subtracted POINT SOURCE TEST -.. (background NOT subtracted) u 6~---=.,,.-.,..-.~~-=-=......,~.....,.,,,,~~~-:=,,-..,...,..--,-.,,.,....,--=-=----

..__, 0 *-4 ~~.;,........,..

~~~~~=-.:.;_~~ :> *..= 2~..;;;~~..-~rnl~~~~~~, 0 \D b O 4=~~;.;.;.;.g..;..:&;~

..;a;.~_,.....J~=;.::....~-;.;...A-..~,;..;.J..:::..U.

=,.:.-.;::;.;.J.-.~~~

u 0 18 48 60 66 72 78 84 90 Offset (inches) Th e Yankee Rowe emp iri ca ll y determined field of v i ew at 2 meters had a radius of at least 2.3 meters (16.6 m 2) which is larger than a calcu l ated fie l d of view with a radius of 2 mete r s and 12 m 2. Since a ll activity detected i s attributed to the calculated field of view , this l eads to conservative estimates of soi l concentrations when a calculated field of view is used in the geometry eff i ciency file.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 9 of 25 Alternately, the field-of-view may be determined by comparing efficiency values for various diameters. For instance, considering a detector positioned at one meter above a surface, a 200-meter diameter could be considered an infinite plane. Efficiencies for this "infinite" diameter would be determined.

Subsequently, efficiencies would be determined for other, much smaller, diameters (e.g., 5.5 m, 6 m, 7 m, etc.) and then compared to the efficiencies associated with the infinite plane. The diameter that yields efficiency values at 95% that of the infinite plane would be considered the of-view for the detector configuration.

As alternative collimator configurations are implemented specific evaluations should be conducted. The DCGLEMc is divided by the geometry adjustment factor to derive investigation Ievels. Since the calculated field of views are smaller than the true fields of view of the detector, use of the calculated field of view and the algorithm corrected efficiencies are fairly flat. Use of calculated field of views is conservative and will slightly over estimate the concentrations ( e.g., pCi/m 2 over 12m 2 as opposed to 16.6 m 2). The following calculated fields of view for the FCS ISOCS geometries are conservative.

Table 1 -Calculated Fields of View 90 Degree Collimator Distance to field of Source view m 2 1 3.14 2 12.57 3 28.27 At Rancho Seco the HPGe had a 40% relative efficiency as opposed to the 50% relative efficiency for the FCS detectors.

A calculated field of view of 28 m 2 was used for 3 meter detector to source geometry at Rancho Seco. Soil lnvestigation Criteria were determined by constructing an initial geometry for soils using a circular plane with a source depth of 15 cm, a radius of 3 m , and a source to detector distance of 3 m. A series of spectra were collected using this geometry with the 90 degree collimator attached to the detector.

Following the original analyses of the collected spectra using the 28 m 2 source geometry at Rancho Seco , the spectra were re-evaluated using a geometry having a 15 cm thick source of 1 m 2 placed at the periphery of the field of view. The analytical results for the small1 m 2 area sources were compared to the results for the large area sources (i.e., the 28 m 2). The ratio of the small source to large source activity is the geometry corre c tion factor by which the DCGLEM c must be divided by to derive the lnvestigation Criterion as shown in the Table 3 below.

Use of ln-Si t u Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 10 o f 25 Table 2 -Rancho Seco Tes t Soil Results for 1 m 2 Source in Periphery of 28 m 2 Field of View 28 m 2 source 1 m 2 source in 28 m 2 field in 28 m 2 field ofview ofview Geometry Geometry Ratio (Small to Sample # Nuclide pC i/m 2 pCi/m 2 Large) Cs-13 7 0.376 9.517 25.31 S3M005 Co-60 <0.2 20 <5.71 25.95 Cs-137 0.48 12.155 25.32 S3M006 Co-60 <0.152 <3.93 25.86 C s-137 0.31 7.842 25.3 S 3M007 Co-60 <0.129 <3.35 25.97 C s-137 0.288 7.298 25.34 S3 M008 Co-60 <0.143 <3.71 25.94 C s-13 7 0.319 8.072 2 5.3 S3M009 Co-60 <0.1 4 8 <3.8 4 25.95 Cs-137 <0.167 Obtained asa background S3M010 Co-60 <0.138 count Cs-137 <0.143 3.624 25.34 S3M011 Co-60 <0.142 <3.68 25.92 C s-137 0.431 10.923 25.34 S3M012 Co-60 <0.137 <3.55 25.91 C s-137 0.411 10.412 25.33 S 3 M013 Co-60 <0.153 <3.96 25.8 8 C s-137 0.273 6.91 25.31 S3M014 Co-60 <0.142 <3.68 25.92 C s-137 0.468 11.841 25.3 S3M015 Co-60 <0.135 <3.49 2 5.85 C s-137 0.554 14.018 25.3 S3M017 Co-60 <0.148 <3.84 25.95 C s-137 0.372 9.416 25.31 S3M018 Co-60 <0.161 <4.18 25.96 C s-13 7 0.376 9.527 25.3 4 S3M019 Co-60 <0.176 <4.55 25.85 Cs-13 7 0.435 10.022 25.34 S3M020 Co-60 <0.147 <3.81 25.92 Cs-137 25.3 Mean Co-60 25.9

Use of ln-Situ Gamma Spectroscopy for Character i zation FC-1 8-0 09 ._...._ -_... Ornaha Pu/J lic Power O isü/d R evisio n 0 P a ge 11 o f 2 5 Using the ab o v e ge o m e try c o rre c ti on f ac t o r s, the Ra n cho Se c o ln v est ig ation Cri t erion for Cs-1 3 7 w as 23.6 pC i/g and f o r Co-60 is 5.7 pCi/g b a sed o n their s ite s pe cifi c DCGLs a nd Area Fa c t o r s. A simil a r methodol o g y usin g a 40% rela t i v e efficienc y HPGe w as us e d at Mai ne Y a nkee w here a spe ctrum was co ll ec t e d a t a 3 mete r h e ight us i ng a 9 0 de g r ee co llimat o r. Th e sp e c trum w as th e n a n a l yz e d using the 28 m 2 and t h e per i pher al 1 m 2 geometries. Th e r es ults a re pro v ided in Figur e 4. The Cs-13 7 DCGLE MC of 22.63 a nd Co-6 0 D C GL EMC of 7.66 a r e in close a greement w ith t he Rancho Se co t e st r es ults. Figure 4 -Maine Yankee 3 meter lnvestigation Level Equivalent DCGLE M C Test Results Inv e stigation Level Equivalent DCGL E M C Test Att 8. Files 28-m 2 Area 1-m 2 Edge nvestigation Le v el Ec Derived Acti v ity (3m height) Geometry DCGLemc / 28m 2 Resuti in 1m 2 at the Geometry Results lnvestigation Level Results EqDCGLemc Co-60 Cs-137 Co-60 Cs-137 Co-60* Cs-1 37* Co-60** Cs-137** (0.36 pC i/g} (1.0 pC i/g) {pCi/g) (pCi/g) 7607-EXC00135 0.25 0.11 5.26 2.49 1.46 9.10 7.67 22.64 7607-EXC00137 0.23 0.13 5.00 2.86 1.54 7.91 7.67 22.64 7607-EXC00138 0.2 1 0.20 4.51 4.63 1.69 4.89 7.64 22.64 7607-EXC00139 0.21 0.17 4.52 3.81 1.70 5.93 7.68 22.64 7607-EXC00141 0.14 0.35 3.01 7.99 2.54 2.83 7.65 22.64 7607-EXC00142 0.13 0.16 2.78 3.59 2.7 6 6.31 7.66 22.64 7607 -EXCOO 14 7 0.12 0.15 2.62 3.33 2.95 6.80 7.7 4 22.64 7607-EXC00155 0.16 0.24 3.40 5.52 2.27 4.10 7.72 22.64 7607-EXC00159 0.14 0.14 2.96 3.11 2.57 7.29 7.6 1 22.64 7607-E XCOO 160 0.12 0.30 2.64 6.82 2.92 3.32 7.72 22.64 7607-EXC00177 0.12 0.34 2.44 7.72 3.13 2.93 7.64 22.64 7722-EXC005 6 4 0.18 0.4 1 3.83 9.24 1.98 2.45 7.59 22.61 7722-EXC00567 0.15 0.18 3.19 4.06 2.39 5.57 7.61 22.61 7722-EXC0057 6 0.12 0.30 2.49 6.72 3.06 3.36 7.64 22.62 *Jn v Lev e l/28 m2 Rcs ult fo r Co-<iO i s (0.3 6 p Ci/g Ave r age 2.3E 5.2C 7.66 22.63 A d m in Va lu c)/Co l. 2 R es ult s (0.36/0.2 5= 1.4 6) **D e ri v cd Ac t Jn v L evc l fo r Co-60 is Co l.4 va lue M m< 3.13 9.1( 7.7 4 22.64 t imcs Co l.6 v a l u c (5 .26x 1.46-7 .67) N o tc t ha t the Cs-13 7 va lu es a r e ca lcul a t ed in a Stdev O.S E 2.11 0.0 44 0.012 s imila r man n cr. Th e F ig ure 4 d a ta s h ow in g th e 28 m 2 to 1 m 2 geo me try cor r ec t ion f ac t o r s is p ro v id ed in T ab l e 3.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Table 3 -Maine Yankee Figure 4 (3 meter) Data with Geometry Factors 28-m 2 Area 1-m 2 Area lnvestigation Level (3m Height) pCi/g (3m Height) pCi/g Geometry Factor pCi/g Aft 8. Files Co-60 Cs-137 Co-60 Cs-137 Co-60 Cs-137 Co-60 Cs-137 7607-EXC00135 0.25 0.11 5.26 2.49 21.04 22.64 1.46 9.10 7607-EXC00137 0.23 0.13 5.00 2.86 21.74 22.00 1.54 7.91 7607-EXC00138 0.21 0.20 4.51 4.63 21.48 23.15 1.69 4.89 7607-EXC00139 0.21 0.17 4.52 3.81 21.52 22.41 1.70 5.93 7607-EXC00141 0.14 0.35 3.01 7.99 21.50 22.83 2.54 2.83 7607-EXC00142 0.13 0.16 2.78 3.59 21.38 22.44 2.76 6.31 7607-EXC00147 0.12 0.15 2.62 3.33 21.83 22.20 2.95 6.80 7607-EXC00155 0.16 0.24 3.40 5.52 21.25 23.00 2.27 4.10 7607-EXC00159 0.14 0.14 2.96 3.11 21.14 22.21 2.57 7.29 7607-EXC00160 0.12 0.30 2.64 6.82 22.00 22.73 2.92 3.32 7607-EXC00177 0.12 0.34 2.44 7.72 20.33 22.71 3.13 2.93 7722-EXC00564 0.18 0.41 3.83 9.24 21.28 22.54 1.98 2.45 7722-EXC00567 0.15 0.18 3.19 4.06 21.27 22.56 2.39 5.57 7722-EXC00576 0.12 0.30 2.49 6.72 20.75 22.40 3.06 3.36 Average 21.32 22.56 2.35 5.20 Ma x 22.00 23.15 3.13 9.1 0 Min 20.33 22.00 1.46 2.4 5 Revision 0 Page 12 of 25 1 m 2 Activity at lnvestigation L evel (DCGLeMc) pCi/g Co-60 Cs-137 7.67 22.64 7.67 22.64 7.64 22.64 7.68 22.64 7.65 22.64 7.66 22.64 7.74 22.64 7.72 22.64 7.61 22.64 7.72 22.64 7.64 22.64 7.5 9 22.61 7.61 22.61 7.64 22.62 7.66 22.63 7.7 4 22.64 7.59 22.61 Th e Maine Yankee geometry correction factors are lower than Rancho Seco's and wou ld yie ld somewhat higher investigation Ievels. At Yankee Rowe the geometry correction factor was developed using a sp e ctrum free of plant-related radioactivity that was analyzed using two different efficiency calibrations (i.e. geometries).

The first scenario assumed radioa c tivity was uniformly distributed over the detector's field-of-view at 2 meters from the source (4.6 meter source diameter).

The second scenario assumed radioactivit y localized within onesquare-meter and was situated at the edge of the detector's field-of-view.

A ratio of the resultant MDC va lu es characterizes the difference in detection efficiencies between the two scenarios. This ratio is the offset geometry adjustment factor. The 2 meter area factors determined at Yanke e Rowe for soils by this method are provided in Figure 5. Th e Cs-137 results were similar to the Maine Yankee and Rancho Seco test with a Cs-137 area factor of 22 and DCGL EMC of 22 pCi/g. Th e Co-60 results were a DCGLE MC of 15 pCi/g with an area factor of 11. This is why the in v estigation Ievel was higher than the Maine Yankee 7.66 pCi/g and the Rancho Seco 5.7 7 pC i/g. There is a greater disparity between the Co-60 and Cs-137 geometry corr e ct ion factors in the Yankee Rowe results than wou ld be anticipated based upon the Maine Yankee and Rancho Seco results. Thi s is probably due to us i ng the ratio of MDCs from a spectrum free of p l ant nuclides as opposed to ca l culated con c entrations based upon spectra containing th e radionuclides. Since the Ranch o Se c o ar e a factors are bounding and r e sult in slight l y low e r inve s tigation I e v e l s they can b e us e d for Use o f ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 13 o f 25 establishing in vestigation Ie vels at FCS. It should also be noteci that the FCS detectors are 50% relative efficient as opposed to the Maine Yankee, R ancho Seco and Yankee Ro we 40% relati ve efficient detectors and are thus capable of greater sensitivities.

Figure 5 -Yanke e Rowe Area Factors and DCGLEMc for Soils SOIL DCGL EMC FOR ONE-SQ UARE-l\1ETER Soil Soil DCGLw DCGLw (p C i/g) (pCi/g) (NOTE 1) (NOTE 2) Co-60 3.8 1.4 Ag-108m 6.9 2.5 Cs-1 34 4.7 1.7 Cs-1 37 8.2 3.0 NOTE l -LTP Table 6-1 NOTE 2 -Adjusted t o 8.7 3 mRc m/yr NOTE 3 -L TP App en di x 6Q 1 m 1 Area Fac tor (NO T E 3) 1 1 9.2 1 6 22 NOTE 4 -Soi l D C GL v (:idjustcd t o 8.73 mRe wJ yr) for a l m 1 arca D CGLE MC for 1 nr (p Ci/g) -(NOT E 4) 15 23 28 66 The Ya nk ee Rowe MDCs and soil in vest i gat i on I evels are provided i n F igure 6. Figure 6 -Yankee Rowe 2 meter Geometry MDCs and Soil lnvestigati on Levels SOIL INVESTIGATION LEVEL DERIVATION INVESTIGA TION DCGLEM C LEVEL MDCpCi/g MDC pCi/g RATIO for 1 m 2 pCi/g (NOTE 1) (NOTE 2) (NOTE3) (NOTE4) (NOTE 5) Co-60 0.121 1.86 0.0651 15 1.0 Ag-0.184 2.82 0.0652 23 1.5 108m Cs-134 0.189 2.90 0.0652 28 l.8 Cs-137 0.1 82 2.78 0.0655 66 4.3 NOTE 1 -Assumed activity d1stnbuted over the detector's field-of-view. N OTE 2 -Efficie nc y ca librat ion modeled for a 1 m 1 arca situa ted (off-set) a t the edge of the detector's ficld-of-vicw. The mode i ass um es th a t a l i ac ti vity is di s tributed within the 1 m 1. NOTE 3 -Ratio = (field-of-view MDC + 1 m 1 MDC). NOTE 4 -DCGLEMc va lu es for I m 1 (from Tab l e 1) NOTE 5 -Investigati on I eve l s derived by app l ying of the off-sc t geometry adjustment factor (e.g. 0.0653) t o the DCGLe."1c for a 1 m i area for each radionuclide.

The NUREG-1757 soi l screen in g DCGL is 11 pCi/g. U s ing an Area F ac tor of 14 for Cs-137 in soils eq u a l s a D CGLEMc of 154 pCi/g. Dividing this by the R a n c ho Seco Use of ln-Situ Gamma Spectroscopy for Characterization FC-1 8-009 Revision 0 Page 14 of 25 geometry factor of 25.3 for Cs-137 yields an investiga tio n Ievel of 6 pCi/g. The investigation Ievel is we ll within the sensitivity capabilities of the 50% relati ve effic i ent ISOCS. Actual soil DCGLEMC values will be calculated using FCS Area Factors calculated for the License Termination Plan. Given the MDAs and lnvestigation Criteria for soil , final surveys of Class 1 MARSSIM areas can be performed on so il with a Type 1 error of 0.05 using in situ gamma spectroscopy fo r seans at FCS. 4.2.2 Structures Current end state plans for FCS are to remove all structures associated with the FCS facilities to 3 feet below grade and backfill them. Therefore, the lndustrial Use screening Ievels in NUREG-1757 and plant specific DCGL w s developed at other facilities such as Rancho Seco are not applicable at FCS s i nce they assume occupancy within the structures.

However , ISOCS surve y s may be conducted to better quantify the source term in the remaining belo w grade structures.

Under the source modeling scenario the assay of the overall remaining source term to demonstrate compliance with the release criteria for license terminat io n is of more importance than the identification of areas with elevated Ie ve ls s i nce significant diffusion of any source term released from concrete w ith elevated contamination Ievels wo uld occur in the down gradient plume to the resident scenario potable w ater well. However , in order to achieve compliance with the release criteria , and to implement ALARA measures, remediation of subsurface structure locations with elevated contamination Ievels may be the most effective way of reducing the overall source term. Remediation of areas with elevated Ie v els reduces the overall source term wi th the least amount of effort. Although it is unlikely that DCGLs w ill be used or DCGL EMCs will be calculated at FCS , it is likely that action Ie vels for ISOCS seans quantifying overall source terms will be established and that there may be action Ie vels or investigation criterion targeting identification of small areas of elevated contamination for remediation.

The following information on the calcu la t ion of DCGLE Mc for ISOCS seans demonstrates that ISOCS seans will have adequate sensitivity to identify small 1 m 2 areas with elevated contamination Ievels on structures.

At Rancho Seco [2] an initial geometry was constructed for concrete structures using a circular plane with a source depth of 2 cm, a radius of 3 m and a source to detector distance of 3 m. A series of spectra were collected using this geometry with the 90 degree collimator attached to the detector.

Source depth at FCS will be evaluated based upon concrete core data from the structures being evaluated (e.g. Reactor Buildings , Auxiliary Building and Turbine Building).

The spectra at Rancho Seco were collected from a concrete wall with low , but detectable Ie ve ls of Cs-137 and Co-60. Analytical results were presented in pCi per m 2 and Cs-137 data were converted to dpm/100 cm 2 in order to demonstrate the sensitivity of the analyses relative to site specific DCGLs (Co-60 was not converted due to higher ambient I evels of cobalt i n the survey area and background was not subtracted from any of the data). Following the original 28 m 2 geometry analyses at Rancho Seco , the data was evaluated using a geometry ha v ing a 2 cm thick source of 1 m 2 pla ced at the periphery of the field of view. The analytical results for the small area sources were compared to the result for the large area sources (the 28 m 2 field of v iew). The ratio of the small Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 15 of 25 source to large source activity is the geometry correction factor by which the DCGLE M C must be divided by to derive the lnvestigation Criterion as shown in the Table 4 below. Table 4 -Rancho Seco Test Concrete Results for 1 m 2 Source in Periphery of 28 m 2 Field of View 1 m 2 source in 28 m 2 source in 28 m 2 field of view 28 m 2 field of Geometry view Geometry Ratio (Small to Sample # Nuclide pCi/m 2 dpm/100 cm 2 pCi/m 2 Large) CRC002 Cs-137 115 , 684 2 , 568 3 , 058 , 9 3 7 26.4 Co-60 9 22 , 077 20,470 24 , 604 , 310 26.7 CRC003 C s-137 30,3 68 674 803 , 012 26.4 Co-60 1 , 182 ,33 5 26 , 24 8 31 , 550 , 6 4 0 26.7 CRC004 Cs-137 84,654 1 , 879 2 , 238 , 500 26.4 Co-60 1 , 176 , 505 26,118 31 , 394 , 350 26.7 CRC005 Cs-137 646,634 14,355 17 , 099 , 200 26.4 Co-60 6 53,756 14,513 17 ,4 44 , 690 26.7 CRC006 C s-137 271 , 698 6 , 032 7 , 184,433 26.4 Co-60 708,836 15 , 736 18 , 915 , 281 26.7 CRC007 C s-1 3 7 54 ,4 94 1 , 210 1,441,027 26.4 Co-60 835 , 5 3 8 18 , 5 4 9 22 , 298 , 770 26.7 CRC008 Cs-1 3 7 36 , 151 803 955 , 918 26.4 Co-60 640 , 738 14 , 224 17,097 , 850 26.7 CRC009 C s-137 2 6 ,2 04 582 692 , 930 26.4 Co-60 417,889 9 , 277 11 , 151 , 050 26.7 CRC010 C s-137 46 , 5 40 1 , 0 33 1 , 230 , 622 26.4 Co-60 1 , 052 ,4 18 23 , 364 2 8 , 080 , 790 26.7 CRC01 1 C s-137 98 , 584 2, 189 2 , 606,865 26.4 Co-60 965 , 999 21,445 25 , 775 , 990 26.7 CRC012 Cs-137 298 , 052 6 , 617 7 , 881 , 140 26.4 Co-60 792 , 04 8 17 , 583 21 , 134 , 200 26.7 CRC013 Cs-137 43 4, 564 9 , 6 4 7 1 1 , 491 , 151 26.4 Co-60 1 , 065 , 999 23 , 6 6 5 28,44 4, 600 26.7 CRC014 C s-137 2 30 , 746 5 , 12 3 6 , 101 , 277 26.4 Co-60 456 , 766 10 , 140 12 , 186 , 860 26.7 CRC015 Cs-137 607 , 692 1 3 ,4 9 1 16 , 068 , 710 26.4 Co-60 3 93 , 634 8 , 739 105 , 04 , 530 26.7 CRC0 1 6 Cs-137 356 , 727 7 , 919 943 , 931 26.4 Co-60 161, 815 3 , 592 43, 1 6, 970 26.7 CRC017 C s-137 30 9, 195 6 ,8 6 4 8 , 175 , 66 1 26.4 Co-60 313,478 6 , 959 83 6,4573 26.7 CRC018 C s-137 156 , 9 2 9 3,484 4 , 149,533 26.4 Co-60 770 , 318 17,101 20 , 555 , 180 26.7 CRC019 Cs-137 75 , 953 1 , 6 86 2 , 008 ,3 71 26.4 Co-60 1 , 0 48 , 3 3 7 23 , 273 27 , 974 , 780 26.7 Mean Cs-137 dpm/100 cm 2 4786 Mean Ratio 26.6 The mean geometry correction factor for Cs-137 was in the same range as for the soil geometry at 26.6. This is primarily due to the difference in the density thickness of the 15 cm soil source and the 2 cm concrete source.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Table 5 -Soil and Concrete Source Density Thickness Typical Density Thickness Density Thickness Modei cm g/cc g/cm 2 Soil 15 1.6 24 Concrete 2 2.34 4.68 Concrete 5 2.34 11.7 Revision 0 Page 16 of 25 The gross beta-gamma DCGL for structures based on the estab l ished nuclide fraction and conditions at Rancho Seco was 43,000 dpm/100 cm 2. Applying the Rancho Seco 14.9 area factor for a 1 m 2 area results in a DCGLE M c of 640 , 700 dpm/100 cm 2. The apparent geometry correction factor for a 1 m 2 elevated area at the edge of the detector field of view of 28 m 2 is 26.6 as shown above in Table 4. Dividing the DCGLEMc value by the geometry factor gives an lnvestigation Criterion of 24 , 000 dpm/100 cm 2 or 1.08E+6 pCi/m 2 or 3.04E+ 7 pCi in a 28 m 2 field of view circular plane geometry.

This means that as long as the in situ gamma spectroscopy result does not exceed 24 , 000 dpm/100 cm 2 , there cannot be an undetected elevated area within the field of view of 1 m 2 which exceeds the DCGLE Mc. Similarly the NUREG-1757 DCGLw is 28,000 dpm/100 cm 2. Applying the Rancho Seco area factor for a 1 m 2 area of 14.9 results in a DCGL E M c of 417 , 200 dpm/100 cm 2. The apparent geometry correction factor for a 1 m 2 ele v ated area at the edge of the detector field of view of 28 m 2 is 26.6 as shown above in Table 4. Dividing the DCGLEM C value by the geometry factor gives an lnvestigation Criterion of 15 , 684 dpm/100 cm 2. It should be noted that this calculation can be adjusted to calculate the highest 1 m 2 area of elevated contamination that could go undetected for any scan by dividing the ISOCS 28 m 2 results by the 1 m 2 geometry correction factor. This could be used to target locations with the highest results for furthe r investigation and potential remediation. Given FCS plans to develop a site specific fate and transport modei to evaluate end state doses from below grade structures it is likely that the investigation Ievels will be higher than those developed for Rancho Seco or those derived from the NUREG-1757 screening Ievels. The Rancho Seco data in Table 6 also indicates that the typical concrete surface MDAs for a 1200 second count with a 40% relative efficient detector are 1318 dpm/100 cm 2 for Cs-1 37 and 562 dpm/100 cm 2 for Co-60. These w ere a small fraction of the Rancho Seco surface DCGL of 43,000 dpm/100 cm 2. Therefore structure characterizations at FCS using 50% relative efficient ISOCS detectors will have more than adequate sensitivity to detect elevated Ievels within the field of view.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 17 of 25 Table 6 -Rancho Seco [2] Concrete Surface 28 m 2 field of view MDA Values for 1200 Second Count CsMDA CoMDA Sample # (pCi/m 2) (pCi/m 2) CRC002 66,400 23,500 CRC003 64,900 30,300 CRC004 84,700 35,200 CRCOOS 60,900 26,800 CRC006 66,600 25,800 CRC007 50,600 27,900 CRC008 49,800 20,200 CRC009 47,900 25 , 000 CRCOlO 53,600 27,300 CRCOll 56 , 300 26 , 200 CRC012 61,800 21 , 900 CRC013 74,800 32,900 CRC014 54,600 18,300 CRC015 50 , 900 18 , 100 CRC016 41,100 20,100 CRC017 52 , 900 17,900 CRC018 66,500 28 , 800 CRC019 64 , 300 29,500 Mean 59,397 125,317 dpm/100 cm 2 1,318 1 , 562 At Yankee Rowe the development of the in vest igation Ievel for building surfaces was identical to that for soil surfaces.

Using th e same approach and a 5 cm thick concrete source , a n offset geometry adjustment factor was developed.

Th e MDC va lues for these two geometries were compared to characterize the difference in detection efficiencies.

As expected, the condition with lo ca liz ed (o n e square-meter) radioactivity at the edge of th e detector's field-of-view yielded higher MDC va l ues. Th e ratio between the reported MDC values for th e two scenarios was used as the offset geometry adjustment factor. Th e Yankee Rowe 2 meter geometry MDC values , the associated ratios , and the derived investigation Ievel for building surfaces are presented in Figure 7.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 18 of 25 Figure 7 -Yankee Rowe Field of View Correction Factors and DCGLEMc for Structures

' .. -TABLE 2, BUILDING SURFACE DCGLEMc FOR ONE-SQUARE-METER Bldg Bldg DCGLw DCGLw (dpm/100m 2) (dpm/1 OOcm 2) (NOTE 1) (NOTE 2) Co-60 18 , 000 6,300 Ag-108m 25,000 8,700 Cs-134 29,000 10,000 Cs-137 63,000 22,000 NOTE 1-LTP Table 6-1 NOTE 2 -Adjusted to 8.73 mRem/yr NOTE 3-LTP Appendix 6S 1 m 2 Area Factor (NOTE 3) 1 7.3 7.2 7.4 7.6 NOTE 4 -Building DCGLw (adjusted to 8.73 mRem/yr) for a 1 m 2 area DCGLEMC For l m 2 (dpm/1 OOcm 2) (NOTE 4) 46,000 62,600 74,000 167,000 The 5 cm thick Yankee Rowe modei and the 2 meter st a ndoff as opposed to the Rancho Seco 2 cm thick source and 3 meter standoff account for the lower Yankee Rowe geometry adjustment factors. The Rancho Seco geometry correction factors with a 3 meter standoff are conservative and appropriate for use at FCS. 4.3 Moisture Content of Soils ln situ gamma spectroscopy of open land areas is inherently subject to various environmental variables not present in laboratory analyses. Mast notably is the impact that water saturation has on assay results. This impact has two components.

First , the total activity result for the assay is assigned over a larger , possibly non-radioactive mass introduced by the presence of water. Secondly , water introduces a absorption factor. The increase in sample mass due to the presence of water is addressed by the application of a massimetric efficiency developed by Canberra lndustries.

Massimetric efficiency units are defined as: (counts per second).;..(gammas per second per gram of sample) Mathematically, this is the product of traditional efficiency and the mass of the sam pie. When the efficiency is express e d this way , the efficiency asymptotically approaches a constant value as the sample becomes very large. Under these conditions changes in sample size, including mass variations from e x cess moisture , have little impact on the counting efficiency.

However , the massimetric efficiency does not completely address attenuation characteristics associated with water in the soil matrix.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 19 of 25 To evaluate the extent of self-absorption at Yankee Ro w e, (traditional) counting efficiencies were compared for two densities. Based on empirical data associated with their monitoring wells, t y pical nominally dry in situ soil i s assigned a density of 1.7 g/cc. They obtained a density of 2.08 g/cc , obtained from a technical reference publication by Thomas J. Glo v er, as representati v e of saturated soil. A density of 2.08 g/cc accounts for a possible water content of 20%. A summary of the Y ankee Rowe comparison is presented in Figure 8. Figure 8 Yankee Rowe Saturated and Unsaturated Soil Counting Efficiency Comparisons Efficiencies Deviation due to density keV 1.7 g/cc 2.08 g/cc increase (excess moisture) 434 3.3 E-6 2.7 E-6 -18.7% 661.65 2.9 E-6 2.4 E-6 -17.5 o/o 1173.22 2.5 E-6 2.1 E-6 -15.4% 1 1332.49 2.4 E-6 2.1 E-6 -14.8% It should be noteci that if a saturated soils geometry i s crea t ed w ith the higher density and it is used rather than the dry soil geometry to anal y ze spectra in locat i ons with wet soil conditions , the algorithm will correct for efficiency differences w hen it a nal y zes the spectra and convert it to pCi/m 2. This will essentially negate the eff i c i enc y differences between wet and dry soil conditions.

ln cases when the soil is observed to contain more than "t y pical" amounts of w ate r, potential under-reporting may occur if the dry soil geomet ry is used to analyze the collected spectrum.

ln general , the presence of stand i ng w a t er (or ice or snow) on the surface of the soil being assayed w ill be not be tolerated d uring Final Status Survey activities. ln cases where minor surface water is present , notes will be made in fie l d logs so that associated measurement results can be re vi e w ed and reanalyzed if necessary using a wet soil geometry. Alternatively , a saturated soil geometry may be used to analyze the spectra in the field. 4.4 Discrete Particles in the Soil Matrix An evaluation was performed at Yankee Rowe assuming all the acti v ity in the detector's field-of-view , to a depth of 15 cm , was situated in a discrete po i nt-source configuration.

A concentration of 1.0 pCi/g (Co-60), c o rresponding to the i nvestigation Ievel correlates to a discrete point-source of appro x imately 3.2 µC i. This acti v ity v alue is considered as the discrete particle of concern. Since the presen c e of an y discrete particles will most likely be accompanied by distributed activity , the investigation Ievel may provide an opportunity to detect discrete partic l es belo w 3.2 µCi of Co-60. Discrete particles exceeding this magnitude would readil y be dete c ted during characterization or investigation surveys. Cs-137 is h i ghl y soluble and is unlikely to remain asa hot particle in an outside area.

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 20 of 25 The MDCs associated with hand-held field instruments used for scan surveys are capable of detecting very small areas of elevated radioactivity that could be present in the form of discrete point sources. The minimum detectable particle activity for these scanning instruments and methods correspond to a small fraction of the license termination 25 mrem/year TEDE limit provided in 1 OCFR20 subpart E. When the investigation Ievel in a Class 1 area is encountered, subsequent investigation surveys will be performed to include the use of hand-held detectors.

The detection sensitivities of instruments used for these surveys will be addressed in the License Termination Plan. Furthermore, discrete point sources do not contribute to the uniformly distributed activity of the survey unit. It is not expected that such sources at this magnitude would impact a survey unit's ability to satisfy the applicable acceptance criteria.

Noting that Class 2 or Class 3 area survey designs do not employ elevated measurement comparisons, associated investigation Ievels are based on positive indications of licensed radioactivity above the DCGL w or above background. Based upon the decay of Co-60 post shutdown and the detection of only background Ievels of Cs-137 in site soils to date, detection of Co-60 in a soil scan will warrant further investigation in all non-impacted and MARSSIM Class 2 and Class 3 areas as well as Class 1 areas. 4.5 Environmental Backgrounds lf background subtraction is used, an appropriate background spectrum will be collected and saved. Count times for environmental backgrounds should exceed the count time associated with the assay. ln areas where the background radioactivity is particularly problematic , the background will be characterized to the point of identifying gradient(s) such that background subtractions are either appropriate or conservative.

Documentation regarding the collection and application of environmental backgrounds will be provided asa component of the final survey plan. 4.6 Quality Control Quality Control (QC) activities for the ISOCS system ensure that the energy calibration is valid and detector resolution is within specifications. A QC file will be set up for each detector system to track response to a multiple-radionuclide check source. The parameters checked/tracked should include peak centroid position , FWHM , and decay-corrected activity (typically for Am-241, Cs-137 , and Co-60). An additional QC file will be set up and maintained for a periodic background check. Quality Control counts will be performed on a per-shift basis when the system is in use. For field operations photopeaks relative to other radionuclides may be used for gain adjustments.

These nuclides include, but are not limited to the 661.6 keV Cs-137 and 1460 keV K-40 energy peaks. lf the energy calibration is found to be out of an acceptable tolerance (e.g., greater than +/-6 channels), then the amplifier gain may be adjusted and a follow-up QC count performed. lf the detector's resolution is found to be above the factory specification, then an evaluation will be performed to determine if the detector should be removed from service and/or if the data is impacted.

Evaluations associated with QC counts shall be documented.

Such documentation may be limited to a remark directly on the applicable QC report or in a logbook if the resolution does not render the s ystem out of servi c e. Otherwise the evaluation should Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision O Page 21 of 25 be separately documented (e.g. Condition Report, etc.) so as to address the impact of any assay results obtained since the last acceptable QC surveillance.

Where it is determined that background subtraction is necessary, a baseline QC system background will be determined specific to that area or location.

When background subtraction is required , a QC system background surveillance will be performed before a set of measurements are made to verify the applicability of the background to be subtracted. Due to the prevailing variability of the background Ievels across the site, the nature and extent of such surveillances will be on a case-by-case basis and should be addressed in the documentation associated with the applicable survey units. ln addition to the routine QC counts , each assay report is routinely reviewed with respect to K-40 to provide indications where amplifier drift impacts nuclide identification routines.

This review precludes the necessity for specific after-shift QC surveillances.

It also minimizes investigations of previously collected data should the system fail a before-use QC surveillance on the next day of use. 4. 7 Data Collection Data collection to support FSS activities will be administered by a specific Survey Package/Plan. Survey Packages/Plans may include an index of measurement locations with associated spectrum filenames to ensure that all the required measurements are made and results appropriately managed. Personnel specifically trained to operate the system will perform data collection activities.

Data collection activities will address environmental conditions that may impact soil moisture content. Logs will be maintained so as to provide a mechanism to annotate such conditions to ensure that efficiency calibration files address the in situ condition(s).

ln extreme cases (e.g. standing water , ice, snow etc.) specific conditions will be addressed to ensure that analysis results reflect the conditions.

As previously discussed with respect to water , when unique environmental conditions exist that may impact analysis results, conservative compensatory factors will be applied to the analysis of the data. 4.8 Efficiency Calibration The centra! feature of the portable ISOCS technology is to support in situ gamma spectroscopy via the application of mathematically derived efficiency calibrations.

The intrinsic efficiency calibrations of the FCS ISOCS are provided in Reference

8. Due to the nature of the environment and surfaces being evaluated (assayed), input parameters for the ISOCS efficiency calibrations will be reviewed on a case-by-case basis to ensure the applicability of the resultant efficiency.

Material densities applied to efficiency calibrations will be documented.

ln practice, a single efficiency calibration file may be applied to the majority of the measurements.

The geometry mast generally employed will be a circular plane assuming uniformly distributed activity.

Efficiency calibrations will address a depth of 15 cm for soil and a depth based on site data such as cor e data for c on c rete s urf ace s. Other geom e tri es (e.g., ex ponential circular plan e, Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 22 of 25 rectangular plane, etc.) will be applied if warranted by the physical attr i butes of the area or surface being evaluated.

Efficiency calibrations are developed by r adiological engineers or instrumentation specialists who have received training with respect to the ISOCS software. Efficiency calibrations will be documented and reviewed and approved in accordance with FCS procedures.

4.9 Contaminant Depth Resolution The ISOCS detectors utilized at FCS are " BeGe" Canberra detectors that utilize a thin carbon composite window over the end cap of the detector.

The thin window contact region and doping of the crystal along with the composite window play a role in the ability of the detector to detect low energy x-ray and gamma energies down to 3.0 keV. This thin window feature can be used to examine the 32 and 661 keV energy lines associated with Cs-137. By examining the ratio of the 32 and 661 keV energy lines , determinations can be made regarding the depth of Cs-137 contamination in concrete.

This approach will allow for determining if the observed activit y is surface o r volumetric in nature. 4.10 ISOCS Uncertainty Evaluator (IUE) As appropriate , the ISOCS Uncertainty Evaluator wi ll be used to e v aluate conditions where parameters associated with the Geom e try Com p oser are not well known. It may also be used to examine the uncertainty associated wi t h known parameter changes due to density , soil moisture and similar conditions that ma y be encountered in a field environment.

The ISOCS Uncertainty Evaluator (IUE) is a tool associated with the Geometry Composer software that may be utilized to improve the qualit y of the gamma spectroscopy uncertainty estimate , improve the ease o f generating these uncertainty estimates, and to document how they were generated. The ISOCS efficiency calibration software is performed in the normai manner to determine the normai reference efficiency for the sam pie being measured.

The efficiency has encoded within it the uncertainty in the efficiency calibration method (as with most efficiency calibrations, this assumes the calibration modei is a perf ec t representation of the sample). The calibration process requir e s defining the sample w i th various parameters.

Some are well known and do not vary appreciably. Others a re not well known (soil composition , soil density , vertical radioactivity distribution , overburden , soil moisture , et c.) and could vary with each location assayed. lnputs are inc l uded to p rovide the IUE software an estimate as to how greatly the parameter(s) vary. Examples include soil density ranges , soil composition , distances and thickness of mater i al. For each unknown parameter the upper and lower limits are provided (input) and a distribution function that the parameter values within the limits are assumed to follow. This could include 1, 2 or 3 standard deviations or if the va l u e s are known as limits they can be assigned a uniform, triangular or other distribution function.

The IUE softw a r e assigns a value for e a ch of th e unknown p a r a m e t e rs followi n g th e

Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009

._.._ -...... Oma/Ja Pu/Jlic Power Dis/ricl Revision 0 Page 23 of 25 probabilities defined by the assigned distribution functions.

The efficiency for the detector and conditions is computed for the modei and the process is repeated a large number of times until adding additional models does not change the results. The software then computes the modei-to modei uncertainty for each energy, which will be combined with the calibration uncertainty and the counting statistics uncertainty.

lf the activity within the object to be measured is distributed in a non-uniform manner the IUE can be used to examine various non-uniform distributions to estimate that portion of the Total Measurement Uncertainty The IUE software also operates in a Sensitivity Mode, where only one parameter is varied at a time. This approach provides a method to determine which parameters are the major contributors to the total uncertainty and, concentrating the data collection resources on the parameters that are most important.

5.0 DATA MANAGEMENT Data management will be implemented in various stages as follows:

• An index or log will be maintained to account for each loca tion where evaluations for elevated activity are performed.

Raw spectrum files will be wr itten directly or copied to a centra! file server.

• Data Analysis -After the spectrum is collected and ana l yzed, a qualified Radiological Engineer will review the results. The data review process inc ludes application of appropriate background, nuclide li braries, and efficiency calibrations.

Data reviews also verify assay results with respect to the applicable in vestigation Ievels and the MDCs achieved.

Data reviews may include monitoring system performance utilizing K-40, Cs-137 , etc. peaks. When the data analysis is completed, the analyzed data file will be archived to a directory l ocated on a centra l file server.

• Data Reporting

-The results of data files whose reviews have been completed and are deemed to be acceptable may be uploaded to a central database for subsequent reporting and statistical analysis.

• Data Archiving

-Routinely (daily) the centralized file server(s) where the raw and analyzed data files are maintained will be backed up.

6.0 CONCLUSION

As demonstrated above , in situ gamma spectroscopy can be employed for performing final surveys with adequate sensitivity of analysis for non-impacted and Class 1, 2, and 3 MARSSIM areas. DCGLEMcs can be calculated for Class 1 MARSS IM Area seans once area factors and the actual DCGL w are calculated for FCS. lnitial evaluations based upon the Rancho Seco, Maine Yankee and Yankee Rowe geometry correction factor data indicate that a geometry correction factor of 26 for a 1 m 2 region at the edge of the field of view field of view is conservative for the 3 meter detector height geometry in soil. The ln vestigation Le ve l for Cs-137 at the NUREG-1757 DCGL w of Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Revision 0 Page 24 of 25 11 pCi/g is in the range of 5.8 pCi/g for soils. Therefore ISOCS seans of FCS Class 1 area soils can readily discern areas requiring further investigation. Given that any source term containing significant Co-60 contamination has less than 80% of the activity deposited due to decay after shutdown. It is unlikely that a Co-60 hot particle of 4.6 µCi would be present in Class 1 soils. lf it were , it would be readily detected by ISOCS. Given that the Area Factor for Co-60 and Cs-137 are predominantly due to e x ternal radiation it is also unlikely that particles below the 4.6 µCi source strength would have any significant dose consequences for future site residents.

ln addition, since Cs-137 is readily soluble , and it is unlikely that it would result in hot particles in soils and would rather be a distributed source bound to clay particles and organic material in the soil. The Rancho Seco data indicates that a structures geometry correction factor of 27 is bounding for a 1 m 2 source at the edge of the field of view for an ISOCS at 3 meters. Using this value and an area factor of 14 indicates that the lnvestigation Level at the NUREG-1757 DCGLw screening Ievel of 28 , 000 dpm/100 cm 2 would be approximately 15,000 dpm/100 cm 2 which is also readily discernible with an ISOCS. Since the source modeling method rather than DCGLs will be used for demonstration of the decommissioning release criteria, the NUREG-1757screening DCGLs for structures are likely very conservative and action Ievels for investigation and remediation of subsurface structures at FCS are likely to be higher given that the NUREG-1757 screening DCGLs are for occupied buildings.

This demonstrates that the ISOCs has sufficient sensitivity for any future uses to quantify below grade source terms for end state structures at FCS. 7.0 ATTACHMENTS None

8.0 REFERENCES

8.1 NUREG-1575, " Multi-Agency Radiation and Site lnvestigation Manual (MARSSIM)," Rev. 1 , August 2000. 8.2 NUREG-1757 , Volume 1 , Revision 2 , "Consolidated Decommissioning Guidance: Characterization , Survey and Determination of Radiological Criteria ," U.S. Nuclear Regulatory Commission , September 2006. 8.3 NUREG-1757 , Volume 2 , Revision 1 , "Consolidated Decommissioning Guidance:

Characterization , Survey and Determination of Radiological Criteria ," U.S. Nuclear Regulatory Commission , September 2006. 8.4 FC 18 002 , "Potential Radionuclides of Concern During the Decommissioning of Fort Calhoun Station ," 2018 8.5 Maine Yankee Calculation EC-003-04 Rev. 1 , " Use of Canberra ln Situ Object Counting System (ISOCS) for FSS Surveys ," November 24 , 2004 Use of ln-Situ Gamma Spectroscopy for Characterization FC-18-009 Re vision 0 Page 25 of 25 8.6 BNL-52607-01

/0 4-Rev Formai Report , " Comparability of ISOCS Instrument ln Radionuclide Characterization At Brookhaven National Laboratory

," Paul Kalb et ai , March 2001 8.7 " Optimum Methods to Determine Radioacti v ity in Large Tracts of Land -ln-situ Gamma Spectroscopy or Sampling Followed by Laboratory Measurements" Frazier Bronson , CHP, Canberra lndustries , 800 Resear ch Par kway, Me r i den, CT 06450 , USA 8.8 ISOCS/LabSOCS Detector Calibration Report -Detector Modei BE5030P , S/N 13218, Mirion Technologies (Canberra), December 2017 Page 1 of 44 A part of Mirion Mirion Technologies (Canberra), Inc. 800 Research Parkway Meriden, CT 06450 Phone: 203-238-2351 Fax: 203-639-2060 ISOCS/LabSOCS Detector Characterization Report Canberra Sales Order #

75766 Detector Model BE5030P S/N 13218 December 12, 2017

Laboratory Measurement s Performed By: Meriden

MCNP/ISOCS Characteriza tion By:

Gabriela Ilie

Approved By:

________________

___________

David Sullivan

Page 2 of 44 Copyright 2017, Mirion Technologies (Canberra), Inc. All rights reserved. The material in this document, including all information, pictures, graphics and text, is the property of Mirion Technologies (Canberra), Inc. and is protected by U.S. copyright laws and international copyright conventions. Mirion Technologies (Canberra), expressly grants the purchaser of this product the right to copy any material in this document for the purchaser's own use, including as part of a submission to regulatory or legal authorities pursuant to the purchaser's legitimate business needs. No material in this document may be copied by any third party, or used for any commercial purpose or for any use other than that granted to the purchaser without the written permission of Mirion Technologies (Canberra), Inc. Mirion Technologies (Canberra), Inc., 800 Research Parkway, Meriden, CT 06450 Tel: 203-238-2351 FAX: 203-235-1347 http://www.canberra.com/. The information in this document describes the product as accurately as possible, but is subject to change without notice. Printed in the United States of America.

Genie, ISOCS, and LabSOCS are trademarks of of Mirion Technologies, Inc. and/or its affiliates in the United States and/or other countries.

For Technical Assistance, please call our Customer Service Hotline at 800-255-6370 or email techsupport@canberra.com

Page 3 of 44 Table of Contents 1.Introduction ..................................................................................... 42.Monte Carlo Modeling ..................................................................... 53.Overview of the ISOCS Characterization Process ....................... 63.1Mathematical Model of the Detector ......................................................................... 63.2Validation of the Detector Model .............................................................................. 63.3Computed Efficiencies for Point Sources with Validated Model .............................. 83.4Gridding Method to Create Detector Calibration Grid .............................................. 83.5Statistical Tests to Validate the Quality of DCG Grids ............................................. 93.6Validation of DCG Efficiencies using Measurements ............................................. 114.Estimated Uncertainties of the Characterization Process

......... 125.ISOXSRCE Measurements & QA Recommendations ................ 146.List of References ......................................................................... 16A.Detector and System Specific Information ................................. 22B.Energy/Shape Calibrations and Hardware Settings ................... 31C.Calibration Source Certificates .................................................... 35D.ISOXSRCE Measurements

............................................................ 39E.Quality Assurance and Quality Control Recommendations ..... 41 Page 4 of 44 1. Introduction This document is a detailed report of the characterization of an HPGe detector for use with Canberra's ISOCS/LabSOCS software packages. The characterization was performed at Mirion Technologies (Canberra), Inc. The main body of text discusses the validation measurements, characterization process, detector characterization grid creation, and total uncertainty of the process. Informati on and calibration re sults specific to your ISOCS/LabSOCS detector and software are given in the appendices. The comparison of the measured data to the characterization results are presented in Appendix A, the energy calibration and hardware settings used for the measurements are presented in Appendix B, and the calibration source certificates are presented in Appendix C. A description of the ISOCS check source measurements is presented in Appendix D, and recommended quality assurance and contro l guidelines are presented in Appendix E.

Page 5 of 44 2. Monte Carlo Modeling The MCNP Monte Carlo physics modeling code was used extensively in the development of the ISOCS characterization. The MCNP code is a direct descendant of the Monte Carlo simulation methods used at Los Alamos during the Manhattan Project for predicting criticality of various geometries [1]. The code simulates detector responses to gamma ray sources by mimicking the inherently random behavior of real physical events. For each simulation, the source/detector geometry is specified via mathematical descriptions of the surfaces and volumes that make up the objects in the "universe." A source region, which can be point-like or distributed, is defined and the code simulates the emission of gamma rays with a specified energy distribution. Each emitted gamma ray is tracked as it interacts with the atoms in the materials it encounters, accurately taking into account the double-differential cross sections for photo-atomic reactions. Tallies (i.e. histograms as functions of energy) of the energy deposited in the model detector are tabulated. The final tally distributions are then given as output from the program; these distributions represent the en ergy-response function of the detector and can thus be used to obtain the full-energy efficiency for the source/detector/universe geometry. Canberra Industries has had a vast amount of experience and success using MCNP in modeling gamma-ray detection systems and in accurately reproducing measured efficiencies [2].

Page 6 of 44 3. Overview of the ISOCS Characterization Process Development of an ISOCS characterization involves three steps. The first is the development and validation of a model for the particular detector to be characterized. The second step is the generation of a large number of efficiency datasets with the validated detector model in response to point-like sources at many locations about the detector. The final step is the generation and validation of the detector characterization file, which contains the relationship of the detector to this point-efficiency data. The end result of this process is a detector parameter file that is used by the ISOCS/LabSOCS Calibration Software. The three steps listed here are each discussed in detail below.

3.1 Mathematical Model of the Detector A model of the HPGe detector is developed based on the physical dimensions of the detector. In order to determine the full-energy peak efficiency response of the detector, an MCNP model of the active bare-crystal and any internal structures, such as the well and internal contact pin, is created. The crystal itself is mo unted in a holder cup, which is in turn surrounded by the detector endcap. The attenuation of the gamma rays passing through these external layers, as well as any crystal dead layers and other various support structures, is computed using ISOCS-based algorithms. Over 30 different dimensions, including the length and diameter of the Ge crystal, the thickness of the dead layer(s), the detector well, holder, and endcap dimensions, are used in developing the model. For Canberra detectors, this information is supplied by our detector production facility. For non-Canberra detectors, these dimensions are obtained from the detector user.

3.2 Validation of the Detector Model In order to develop an accurate model (and hence characterization), it is necessary to determine many of these dimensions to higher degree of accuracy than is normally known in the detector manufacturing process. In addition, certain critical dimensions are not physically measurable at all. Ultimately, the most sensitive and accurate way to develop the complete model is by comparison with traceable source measurements.

To refine and validate the detector model, the computed efficiencies for five different source geometries are compared against the corresponding measured efficiency values determined from well defined point source standards of a mixed Am-241/Eu-152 source and a mixed Am-241/Cs-137 source. The certificat e activities for the sources used in this validation process are presented in Appendix C. The per-decay yields for gamma and X-rays of interest in Eu-152 and Cs-137 are obtained from the Evaluated Nuclear Structure Data Files (ENSDF) database [3], while the decay yields for the low energy gamma and X-ray radiation in Am-241 are taken from Ref. [4].

Page 7 of 44 The validation of the detector model to these measured reference data is an iterative process whereby the initial model dimensions are used as a starting point. The dimensions are adjusted slightly to provide optimum agreement between the computed efficiencies and the measured efficiencies. The source geometries used in the validation process are the following:

1. Am-241/Eu-152 point source on the detector axis, nominally 30 cm from the endcap face (Figure 1), 2. Am-241/Eu-152 point source at 90, 2 cm below the endcap face, nominally 32 cm from the axis of Ge crystal (Figure 2), 3. Am-241/Eu-152 point source at 135, at a lateral distance of approximately 22 cm from the axis of Ge crystal (Figure 3), 4. Am-241/Cs-137 point source mounted on a 3 mm thick Plexiglas disk, positioned 10.4 cm from the detector endcap face (Figure 4), 5. Am-241/Cs-137 point source mounted on a 3 mm thick Plexiglas disk, positioned directly on the face of the detector endcap (Figure 5).

For measurements 1, 2, and 3, the source is mounted in a specially built jig which is attached to the detector endcap during the source measurements. This jig, depicted in Figures 1 through 3, provides very accurate and reproducible source positioning.

For the 90 and 135 point source geometries, three measurements are performed with the source positioned at three equi-spaced azimuthal positions (i.e. 0 , 120 , and 240) about the detector axis. These are performed to verify that the germanium crystal is mounted symmetrically inside the endcap. The measured efficiencies from the three azimuthal positions are averaged at each gamma-ray energy; these average values are used as the measured 90 and 135 efficiencies. Table A1.1 gives the efficiencies for the three 90 measurements, their average, and the percent deviation from the average.

Two of the source geometries utilize the Am-241/Cs-137 point source mounted on a 3 mm thick Plexiglas disk. For one of the validation measurements, the source/Plexiglas assembly is placed directly on the detector endcap face. For the other disk measurement, the same source is used with a Plexiglas spacer cylinder, 10.17 cm tall, placed between it and the detector endcap to in sure position reproducibility.

The Am-241/Eu-152 and the Am-241/Cs-137 point sources used in these characterization measurements are NIST-traceable sources manufactured by Eckert and Ziegler (Type C capsule). The active portion of the source is 3.3 mm in diameter, deposited into a cylindrical bore within a rectangular source capsule (measuring 23.5 mm x 10.9 mm x 1.9 mm). The active source is mixed in a 1.5 mm thick porous glass cylinder located 0.34 mm into the depth of the capsule. The certificates for these sources are included in Appendix C.

Tables A1.2a, A1.2b, and A1.2c give the comparisons of the optimized computed efficiencies with measured efficiencies for the 0 , 90 , and 135 point source geometries, Page 8 of 44 respectively. The computed and measured efficiencies for the near and far disk mounted geometries are given in Tables A1.2d and A1.2e, respectively. In each of these tables the measurement and model uncertainties are presented based on the total uncertainty analysis discussed and presented on pages 12 and 13 of this document. The 1 error columns are the propagation of the measured and model uncertainties and the Dev./ columns indicate the deviation per sigma to which the model and measurements agree within these uncertainties. 3.3 Computed Efficiencies for Point Sources with Validated Model Once the model of the detector is validated against measured efficiencies, the model is used to generate energy/efficiency/uncertainty triplets. The efficiencies are generated at a large number of point "source" locations, in vacuum, and at 20 energies between 10 keV and 7000 keV. The point source locations are chosen to fill a semicircular plane extending from 0 degrees (i.e. on the detector axis, in front of the detector) to 180 degrees (i.e. behind the detector), and extending from the center of the front face of the detector endcap out to a radius of 500 meters. The point locations are generated in Ln(R)- coordinates, R being the radius in centimeters, and being the angle in radians (Figure 7). The X axis represents the angle , and the Y-axis represents Ln(R). As seen from Figure 6, the points are in a grid pattern, spanning the entire semicircular plane. The number of point locations depends on the size of the crystal and the dimensions of the detector endcap. The density of points at the vicinity of the detector endcap is higher than in other regions.

3.4 Gridding Method to Create Detector Calibration Grid The calculations described above yield efficiencies at each point location in the Ln(R)- grid, at 20 different energies. The first step in producing a Detector Ca libration Grid (DCG) file is to sort the bare-crystal efficiencies at a given energy by the X coordinate

(), and then by the Y coordinate [Ln(R)]. Next, using the cubic spline interpolation technique, the efficiencies at a large number of noda l points are generated by interpolating between the bare-crystal reference data. The DCG process thus creates a spatially dense grid of efficiencies in the Ln(R)- coordinates, at each of the 20 photon energies. Once the full grid of bare-crystal efficiencies is created, the attenuation due to the external crystal structures are computed point-by-point using the ISOCS-based computational algorithms. The properly attenuated efficiency grids at the 20 energies are then combined to produce the ISOCS detector characterization. The efficiency at any arbitrary spatial point between the grid nodes is obtained by linear interpolation along the Ln(R) and directions. At a given spatial location, the efficiency at any arbitrary energy between 10 keV and 7000 keV is obtained by parabolic interpolation between the energy grids.

Page 9 of 44 Due to the geometry of the detector, its efficiency response is cylindrically symmetric about its axis. Therefore, the response characterization that is valid within a semicircular plane of a given radius is also valid within a hemispherical region about the symmetry axis of the detector. In other words, the ISOCS characterization represents the detector's response to a point source in vacuum, anywhere within a sphere of 500 meter radius, centered about the detector, and at any energy between 10 keV and 7 MeV. Given the DCG grids, the ISOCS/LabSOCS software can then calculate the efficiency for macroscopic sources by integrating the re sponse over the active volume(s) of a given geometry, taking into account the attenuation through the materials in the geometry.

3.5 Statistical Tests to Validate the Quality of DCG Grids Statistical Report:

A statistical test is performed to check the interpolation quality of the bare-crystal DCG grids. The test involves a bootstrapping method. First, a secondary set of point source locations is generated, intermediate to the primary set of points. Efficiencies at the secondary points are determined by linear interpolation, using the primary DCG grids. Using the efficiencies at the intermediate points, a secondary set of DCG grids (DCG2) are created. From the secondary DCG, the efficiencies at the primary point locations are determined and compared to the MCNP efficiencies at the primary points.

Within a specified spatial region, the relative deviation of the grid efficiencies with respect to the MCNP efficien cies is given as follows:

MCNPeff MCNPeff eff DCG RD)2 (100% The % Average Relative Deviation (%ARD) = Sum(%RD) / N, where N is the number of points in the specified region.

Standard Deviation of N ARD RD RD2%%% For efficiency data points within a DCG re gion and at the various photon energies at which the DCG grids have been created, the following statistics are reported:

1. The % Average Relative Deviation of the DCG2 efficiencies with respect to the MCNP efficiencies, 2. The % Standard Deviation in these relative deviations, 3. The % Standard Deviation of the MCNP data, averaged over the number of points in the DCG region, 4. The number of efficiency data points that are within 1 between 1 and 2 and between 2 and 3 confidence intervals, at the various DCG energies, 5. The number of data points that are outside the 3 limit.

Page 10 of 44 The above mentioned statistics are printed out for 6 different pre-defined spatial regions where the laboratory or the in-situ users are most likely to locate their samples. The relative deviations and the standard deviations are calculated for those data points that are within these spatial regions only. This data is meant to provide the user with information regarding the quality of the response characterization within these regions. The pre-defined regions are as follows.

Region1: This region represents a laboratory source that is 2.5 cm in radius and 6 cm in height (e.g. a liquid scintillation vial), located directly on the detector endcap face.

Region 2: This region represents a disk source with a radius of 5 cm and a thickness of 0.5 cm (e.g. a filter paper or evaporated liquid), located directly on the detector endcap face.

Region 3: It represents a Marinelli Beaker, with a well diameter of 10 cm, a well depth of 10 cm (a volume of 1 liter approximately), and bottom thickness of 4 cm.

Region 4: This is a region in space de-limited by a minimum radius of 20 cm and a maximum radius of 1 meter. This region may be of interest to both laboratory and in-situ users.

Region 5: This is a spatial region with a minimum radius of 1 meter and a maximum radius of 2 meters. This region is of interest primarily to an in-situ user.

Region 6: This region extends in space from a minimum radius of 2 meters to a maximum radius of 500 meters. This region is of interest primarily to in-situ users.

In the statistical report, the target values of average relative de viation and the percent standard deviation are indicated for each of the 6 regions, at all DCG energies. For the average relative deviation of DCG2 efficiencies, the target value is 1% at all DCG energies. For the standard deviation of the relative deviations, the target value is + 2% at all DCG energies.

Three different statistical summaries are provided in the report. The 'Statistical Bias Summary' verifies whether the average relative deviations are within the % standard deviation limits that have been obtained. Average relative deviation values that exceed 1 standard deviation are indi cated by an asterisk(*) at the appropriate energy, and ARDs that exceed 2 are indicated by (**). Large ARD values that exceed the 1 limit may indicate of a bias in the data. The second summary titled 'Absolute Bias Summary' compares the average relative deviations of DCG2 efficiencies, with the target relative deviation (TRD) of 1%. Once again, if the average relative deviations exceed the TRD or 2TRD, such an occurrence is indicated by an

• or **, respectively, at the appropriate DCG energies. This would quantify the absolute bias in the group of efficiency data at a given DCG energy. The third and final summary titled 'Standard Deviation Summary' compares the standard deviation of the relative deviations of DCG2 efficiencies against the target standard deviations (TSD). If the observed standard deviation values exceed Page 11 of 44 the TSD limits, the occurrence is indicated at the corresponding DCG energies. Large standard deviations are indi cative of poor data quality.

3.6 Validation of DCG Efficiencies using Measurements Finally, to come full circle and to compare once again with measurements, the file containing DCG grid is loaded into LabSOCS/ISOCS user-interface software, and efficiencies are generated for the 0 , 90 , and 135 point source geometries, as well as the Plexiglas-mounted source geometries. Figure A1.1 and Tables A1.3a- A1.3e present the results of comparison of LabSOCS/ISOCS efficiencies with measured efficiencies, for the five source geometries. The measurement uncertainties in these tables are presented for each data set. The uncertainties on the ISOCS efficiencies are based on the standard deviation of these efficiencies compared to the measured efficiencies for a large number of germanium detectors of various model types. Since this uncertainty effectively includes the measurement uncertainties, the 1 error columns are simply a reproduction of these uncertainties. The Dev./ columns indicate the deviation per sigma to which the model and measurement efficiencies agree within these uncertainties.

Page 12 of 44 4. Estimated Uncertainties of the Characterization Process There are several contributing factors to the final uncertainty of the characterization process. The sources of uncertainty for the validation measurements and source modeling are summarized in the following tables as one standard deviation uncertainties in percent (%). It should be noted that measurements less than 39 keV from the front and side of the detector and less than 60 keV from the back of the detector are not possible at the factory; therefore the uncertainties for these locations are not estimated.

The independent contributors to the total measurement uncertainties listed in Tables 1a through 1d are the following:

Source Activity - This is the uncertainty in the source activity as provided in the source certificate and verified by independent measurements. Decay Yield - Accepted per decay yield uncertainties for the specific gamma or X-ray. Yields for Eu-152 and Cs-137 lines are from Ref. 3 and Am-241 transition yields are from Ref. 4. Statistical Accuracy

- The typical Poisson uncertain ty from the peak area. For the specific measurement uncertainties please refer to the tables in Appendix A. Peak Analysis - The estimated uncertainty due to peak area analysis. This includes uncertainties due to the modeli ng of the background and differences due to equivalently valid choi ces of initial conditions. Geometrical - Uncertainty inherent in the source positioning reproducibility. Electronic - Estimated uncertainties in the system data acquisition, including dead time and pulse pile-up correction effects.

The independent contributors to the total model uncertainties are the following:

Simulation Precision - Maximum uncertainty in the Monte-Carlo simulation tallies. These uncertainties are typically less than this uncertainty. For the specific simulation uncertainties for this characterization please refer to the tables in Appendix A. Model Approximation - Estimated uncertainty inhere nt in the physical modeling of the detector.

The overall characterization uncertainty is a propagation of all the above factors.

Page 13 of 44 Table 1a. One standard deviation uncertainties (%) for 241 Am 152Eu point source on axis at 29 cm 13.9 17.8 26.3 39.9 59.5 122 245 344 779 1112 1408 Source Activity 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Decay Yield 3.0 3.1 4.2 2.3 0.3 0.5 0.5 1.9 1.1 0.5 0.5 Statistical Accuracy 0.4 0.3 0.7 0.1 0.1 0.1 0.4 0.1 0.3 0.2 0.2 Peak Analysis 7.0 7.0 7.0 3.5 0.5 0.5 1.4 0.5 0.5 0.75 0.5 Geometrical 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Electronic 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Simulation Precision 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Model Approx. 4.0 4.0 3.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Total Uncertainty 8.9 8.9 9.4 4.9 2.9 2.8 3.1 3.3 2.9 2.8 2.7 Table 1b. One standard deviation uncertainties (%) for 241 Am 152Eu point source at 90 degrees 13.9 17.8 26.3 39.9 59.5 122 245 344 779 1112 1408 Source Activity -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Decay Yield -- -- -- 2.3 0.3 0.5 0.5 1.9 1.1 0.5 0.5 Statistical Accuracy -- -- -- 0.5 0.2 0.1 0.4 0.1 0.3 0.2 0.2 Peak Analysis -- -- -- 3.5 0.5 0.5 1.4 0.5 0.5 0.75 0.5 Geometrical -- -- -- 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Electronic -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Simulation Precision -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Model Approx. -- -- -- 20.0 10.0 7.0 5.0 4.0 4.0 4.0 4.0 Total Uncertainty -- -- -- 20.5 10.2 7.3 5.5 4.8 4.5 4.5 4.4 Table 1c. One standard deviation uncertainties (%) for 241 Am 152Eu point source at 135 degrees 13.9 17.8 26.3 39.9 59.5 122 245 344 779 1112 1408 Source Activity -- -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Decay Yield -- -- -- -- 0.3 0.5 0.5 1.9 1.1 0.5 0.5 Statistical Accuracy -- -- -- -- 1.0 0.3 0.1 0.4 0.1 0.3 0.2 Peak Analysis -- -- -- -- 3.5 0.5 0.5 1.4 0.5 0.5 0.75 Geometrical -- -- -- -- 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Electronic -- -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Simulation Precision -- -- -- -- 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Model Approx. -- -- -- -- 25.0 15.0 10.0 10.0 10.0 7.0 7.0 Total Uncertainty -- -- -- -- 25.4 15.2 10.2 10.3 10.3 7.3 7.3 Table 1d. One standard deviation uncertainties (%) for 241 Am 137Cs source geometries 241 Am 137Cs on end cap 241 Am 137Cs on axis at 10 cm 13.9 17.8 26.3 59.5 662 13.9 17.8 26.3 59.5 662 Source Activity 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Decay Yield 3.0 3.1 4.2 0.3 0.3 3.0 3.1 4.2 0.3 0.3 Statistical Accuracy 0.4 0.3 0.7 0.1 0.1 0.4 0.3 0.7 0.1 0.1 Peak Analysis 7.0 7.0 7.0 0.5 0.5 7.0 7.0 7.0 0.5 0.5 Geometrical 0.75 0.75 0.75 0.75 0.75 0.5 0.5 0.5 0.5 0.5 Electronic 3.0 3.0 3.0 3.0 3.0 1.0 1.0 1.0 1.0 1.0 Simulation Precision 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Model Approx. 4.5 4.5 3.0 2.5 2.5 4.0 4.0 3.0 2.0 2.0 Total Uncertainty 9.6 9.6 9.9 4.4 4.3 8.9 9.0 9.5 3.0 2.7

Page 14 of 44 5. ISOXSRCE Measurements & QA Recommendations The ISOCS/LabSOCS characterization is based on the properties and dimensions of the HPGe detector at the time that it is characterized. Therefore, any changes in the Ge crystal properties could potentially induce a bias in the ISOCS/LabSOCS efficiency calculations. For example, in coaxial HPGe detectors, the thickness of the lithium dead layer(s) is known to increase over a period of several years if the detector is not kept cooled. A thicker dead layer would mean a higher attenuation of gamma rays, especially at low energies, and consequently a lower response to the measured radiation. Additionally, as a dead layer increases, it reduces the total active Ge volume, which causes a decrease in efficiency at all energies. These changes over time will result in a gradually increasing discrepancy between the actual detector efficiency and the efficiency response as reflected by the characterization. This will cause measured sample activities to be biased low.

If included in the ISOCS/LabSOCS ch aracterization, the ISOXSRCE Detector Characterization Check Source can have two primary uses:

1) Primarily, it is intended to track the relative changes in detector efficiency for general Quality Assurance purposes. It is imperative that users institute a QA procedure to verify that the ISOCS characterization and the rest of the electronics/software chain continue to be valid. While there is a great degree of flexibility in terms of which source and measurement geometry to use for a QA procedure, it is recommended that at minimum , the ISOXSRCE Check Source be used as described in Appendix D of this document. Further recommendations regarding QA procedures are given in Appendix E of this document. Note also that the ISOXSRCE Check Source Fixture User's Manual has detailed discussions on the use of the ISOXSRCE Check Source as well as on implementation of QA procedures.

2) If it is believed that a change in detector efficiency has occurred solely due to an increase in dead layer thickness, data collected in the field with this source can be used at the Canberra production facility to estimate the change in dead layer thickness and to generate a new characterization. This alleviates the need to send the detector back to Canberra's production facility fo r a full recharacterization. Th is is described in Appendix D of this document.

Prior to shipment, if the ISOXSRCE was included in the ISOCS/LabSOCS

characterization, a baseline dataset was collected at Canberra's production facility using the detector and its associated ISOXSRCE Check Source. The details of these ISOXSRCE measurements are discussed in Appendix D of this document as well as in the ISOXSRCE Check Source Fixture User's Manual. Tables A1.5a and A1.5b present the baseline dataset from the ISOXSRCE measurements performed at the factory, as well Page 15 of 44 as the serial number of the source used for these measurements. The certificate describing this source is in Appendix C.

A key aspect of a good QA program is the establishment of a baseline set of measurements. Consequently, as soon as possible after the ISOCS characterized detector and the check source are received from the factory, users are strongly advised to set up the system with their own electronics and generate their own base line results for the various QC parameters. An example of this using the ISOXSRCE Check Source is presented in Appendix D of this document. The results of these baseline measurements should not be appreciably different from those obtained at Canberra's production facility. Furthermore, if other check sources are to be used as part of the QA program, these should also be measured at this time to establish a baseline as well as a cross-reference to the ISOXSRCE source.

Page 16 of 44 6. List of References

[1] Breismeister, J.F. (ed.), MCNP-A general Monte Carlo N particle Transport Code Version 4C, Los Alamos National Laboratory Report LA-13709-M (March 2000). [2] Bronson, F.L., and Wang, L., Validation of the MCNP Monte Carlo Code for Germanium Detector Gamma Efficiency Calibrations , In Proceedings of International Conference WM '96, February 25-29, 1996, Tucson, AZ.

[3] Evaluated Nuclear Structure Data File (ENSDF), National Nuclear Data Center, Brookhaven National Laboratory.

http://www.nndc.bnl.gov/ensdf/. [4] Lepy, M.C., Plagnard, J., and Ferreux L., Measurement of 241Am L X-ray emission probabilities , Applied Radiation and Isotopes.

66 (2008) 715.

Page 17 of 44 Figure 1. Am-241/Eu-152 point source On-Axis.

Page 18 of 44 Figure 2. Am-241/Eu-152 point source at 90.

Page 19 of 44 Figure 3. Am-241/Eu-152 point source at 135.

Page 20 of 44

Figure 4. Am-241/Cs-137 point source 104 mm from endcap.

Figure 5. Am-241/Cs-137 point source on endcap.

Ge 3 mm thick Plexiglas disk Am/Cs source Ge 3 mm thick Plexiglas disk Am/Cs source 101.7 mm Plexiglas spacer Page 21 of 44 Figure 6. MCNP point locations.

-2 0 2

4 6 8 100306090120150180Ln(R [cm])Angle [degrees]

Detector Page 22 of 44 A. Detector and System Specific Information The In Situ Object Counting System (ISOCS) is designed to count a wide variety of source geometries and to report activities of gamma-ray emitting radioisotopes which may be present in the source. ISOCS is ideally suited for assaying large samples in an uncollimated or a collimated counting geometry.

The Laboratory Sourceless Calibration Software (LabSOCS) is ideal for performing efficiency calibration of laboratory counting geometries such as filter papers, vials, bottles, and Marinelli Beakers. Using LabSOCS, containers of any shape may be custom defined, as long as the shape is rotationally symmetric. Using LabSOCS with Canberra's Genie 2000 software, gamma ray spectra from a variety of source geometries may be analyzed and nuclide activities reported.

The sales number for this order is 75766. The system assembled for this order consists of one 50 cm2 BE5030P germanium detector (serial number 13218).

For a typical ISOCS system, gamma-ray spectra from the detector are accumulated and processed using a Lynx MCA. The data is stored on a Laptop PC. The system is controlled and spectra analyzed by the Genie2000 software. Efficiencies may be generated using ISOCS software.

For a system using LabSOCS, users may employ their own set of electronics to acquire gamma ray spectra in their laboratory. Efficiencies may be generated using LabSOCS software and used with Genie2000.

Page 23 of 44 Data Distributed on Disk The end result of the characterization process described in this report is a set of 20 efficiency grids, corresponding to the 20 energies between 10 keV - 7000 keV; all the energy grids having been compressed into a single binary file. The LabSOCS/ISOCS software generates efficiencies for sources of nearly any shape or size, based on this detector characterization file. The name of this binary file is the same as the detector serial number with an extension of PAR. The detector will be referenced in the user-interface menu structure using this same label.

In addition to this report and the characterization file, five other files are included on the disk:

DETECTOR.TXT -- contains additional detector information required by the ISOCS/LabSOCS software.

README.TXT -- contains detailed instructions on how to install the characterization and DETECTOR.TXT files on the computer. This can be done manually, or automatically. Both methods are described in README.TXT.

9231598B_ISOXSRCE_USERS_MANUAL.PDF -- This is the user's manual for the ISOXSRCE check source. It contains a detailed description of the source, along with instructions on how to properly use the source to track any relative changes in the detector's efficiency and to determine any dead layer growth. (This is included only if the ISOCS characterization ordered included an ISOXSRCE check source with the measurements)

Page 24 of 44 Table A1.1. Point source at 90 degrees: Efficiency at different azimuthal angles.

Source located at 90 degrees Efficiency at different Azimuthal angles 0 degrees 120 degrees 240 degrees Average Nuclide E (keV) Efficiency Uncertainty Efficiency Uncertainty Efficiency Uncertainty Efficiency Uncertainty Eu-152 39.9 1.70E-05 7.53% 1.46E-05 10.86% 1.46E-05 11.89% 1.54E-05 5.86% Am-241 59.5 1.66E-04 2.13% 1.65E-04 2.12% 1.66E-04 2.12% 1.66E-04 1.09% Eu-152 121.8 9.79E-04 1.78% 9.64E-04 1.78% 9.63E-04 1.78% 9.68E-04 0.82% 244.7 9.22E-04 2.32% 9.08E-04 2.32% 9.28E-04 2.31% 9.19E-04 1.19% 344.3 7.47E-04 2.53% 7.51E-04 2.53% 7.49E-04 2.53% 7.49E-04 1.03% 778.9 4.19E-04 2.27% 4.28E-04 2.24% 4.24E-04 2.25% 4.24E-04 1.06% 1112.1 3.35E-04 2.04% 3.27E-04 2.04% 3.29E-04 2.04% 3.31E-04 1.01% 1408.0 2.84E-04 1.91% 2.78E-04 1.92% 2.84E-04 1.92% 2.82E-04 0.92% Nuclide E (keV) Average Efficiency  % deviation from Average 0 deg 120 deg 240 deg Eu-152 39.9 1.54E-05 10.48% -5.11% -5.38% Am-241 59.5 1.66E-04 0.27% -0.33% 0.06% Eu-152 121.8 9.68E-04 1.07% -0.48% -0.59% 244.6 9.19E-04 0.32% -1.28% 0.96% 344.3 7.49E-04 -0.28% 0.30% -0.02% 778.9 4.24E-04 -1.01% 0.91% 0.10% 1112.0 3.31E-04 1.38% -0.94% -0.44% 1408.0 2.82E-04 0.84% -1.42% 0.58%

Page 25 of 44 Table A1.2a.

241Am-152 Eu point source on axis: Comparison of Modeled vs. Measured Efficiencies. Source located at 0 degrees Measured Efficiency Model Efficiency Ratio of Model eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 1.77E-03 7.24% 1.66E-03 4.07% 0.936 0.078 -0.8 17.8 2.49E-03 7.22% 2.46E-03 4.06% 0.987 0.082 -0.2 26.3 3.05E-03 7.35% 3.24E-03 3.06% 1.062 0.085 0.7 Eu-152 39.9 3.47E-03 4.12% 3.57E-03 2.09% 1.029 0.048 0.6 Am-241 59.5 3.63E-03 1.66% 3.66E-03 2.09% 1.008 0.027 0.3 Eu-152 121.8 3.50E-03 1.74% 3.45E-03 2.09% 0.986 0.027 -0.5 244.7 2.18E-03 2.21% 2.18E-03 2.14% 0.999 0.031 0.0 344.3 1.56E-03 2.49% 1.54E-03 2.20% 0.988 0.033 -0.4 778.9 7.06E-04 2.07% 6.97E-04 2.23% 0.986 0.030 -0.5 1112.1 5.07E-04 1.92% 5.10E-04 2.22% 1.006 0.030 0.2 1408.0 4.08E-04 1.82% 4.18E-04 2.22% 1.025 0.029 0.9 Weighted Average 1.001 0.011 Table A1.2b.

241Am-152 Eu point source at 90 degrees: Comparison of Modeled vs. Measured Efficiencies. Source located at 90 degrees Measured Efficiency Model Efficiency Ratio of Model eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Eu-152 39.9 1.54E-05 5.86% 1.32E-05 20.02% 0.855 0.178 -0.8 Am-241 59.5 1.66E-04 1.09% 1.74E-04 10.04% 1.047 0.106 0.4 Eu-152 121.8 9.68E-04 0.82% 9.39E-04 7.06% 0.970 0.069 -0.4 244.7 9.19E-04 1.19% 8.94E-04 5.10% 0.972 0.051 -0.5 344.3 7.49E-04 1.03% 7.24E-04 4.12% 0.966 0.041 -0.8 778.9 4.24E-04 1.06% 4.15E-04 4.12% 0.980 0.042 -0.5 1112.1 3.31E-04 1.01% 3.25E-04 4.12% 0.983 0.042 -0.4 1408.0 2.82E-04 0.92% 2.78E-04 4.12% 0.987 0.042 -0.3 Weighted Average 0.978 0.018 Table A1.2c.

241Am-152 Eu point source at 135 degrees: Comparison of Modeled vs. Measured Efficiencies. Source located at 135 degrees Measured Efficiency Model Efficiency Ratio of Model eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 59.5 6.11E-05 5.75% 6.13E-05 15.01% 1.004 0.161 0.0 Eu-152 121.8 1.11E-03 2.46% 1.08E-03 10.02% 0.971 0.100 -0.3 244.7 1.14E-03 3.51% 1.13E-03 10.04% 0.990 0.105 -0.1 344.3 9.08E-04 3.07% 8.88E-04 10.05% 0.978 0.103 -0.2 778.9 4.89E-04 3.08% 4.87E-04 7.07% 0.995 0.077 -0.1 1112.1 3.74E-04 2.97% 3.80E-04 7.07% 1.017 0.078 0.2 1408.0 3.16E-04 2.73% 3.20E-04 7.07% 1.013 0.077 0.2 Weighted Average 0.998 0.035 Page 26 of 44 Table A1.2d.

241Am-137 Cs point source on end cap: Comparison of Modeled vs. Measured Efficiencies.

Source located at 0 degrees Measured Efficiency Model Efficiency Ratio of Model eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 6.30E-02 7.80% 6.22E-02 15.03% 0.987 0.167 -0.1 17.8 1.29E-01 7.78% 1.31E-01 15.02% 1.016 0.172 0.1 26.3 2.09E-01 7.87% 2.23E-01 10.02% 1.064 0.136 0.5 59.5 2.79E-01 3.35% 2.81E-01 2.58% 1.009 0.043 0.2 Cs-137 661.7 6.88E-02 3.52% 6.85E-02 2.69% 0.995 0.044 -0.1 Weighted Average 1.005 0.029 Table A1.2e.

241Am-137Cs point source at 10.4 cm from end cap: Comparison of Modeled vs. Measured Efficiencies. Source located at 0 degrees Measured Efficiency Model Efficiency Ratio of Model eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 4.04E-03 7.30% 3.83E-03 15.03% 0.948 0.158 -0.3 17.8 9.93E-03 7.25% 9.05E-03 15.03% 0.911 0.152 -0.6 26.3 1.67E-02 7.46% 1.61E-02 10.03% 0.964 0.120 -0.3 59.5 2.07E-02 1.73% 2.06E-02 2.11% 0.993 0.027 -0.2 Cs-137 661.7 4.69E-03 2.04% 4.80E-03 2.23% 1.025 0.031 0.8 Weighted Average 1.003 0.020 Page 27 of 44 Figure A1.1. ISOCS efficiencies (solid lines) compared to experimental measurements (points) for validation geometries.

1.E-071.E-061.E-051.E-041.E-03 1.E-021.E-01 1.E+0010100100010000 EfficiencyEnergy (keV)0 degrees90 degrees135 degreesOn axis at End CapOn axis at 10 cm Page 28 of 44 Table A1.3a.

241Am-152 Eu point source on axis: Comparison of ISOCS vs. Measured Efficiencies.

Source located at 0 degrees Measured Efficiency ISOCS Efficiency Ratio of ISOCS eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 1.77E-03 7.24% 1.69E-03 10.00% 0.955 0.118 -0.4 17.8 2.49E-03 7.22% 2.49E-03 10.00% 1.000 0.123 0.0 26.3 3.05E-03 7.35% 3.24E-03 10.00% 1.064 0.132 0.5 Eu-152 39.9 3.47E-03 4.12% 3.57E-03 6.00% 1.028 0.075 0.4 Am-241 59.5 3.63E-03 1.66% 3.66E-03 3.00% 1.008 0.035 0.2 Eu-152 121.8 3.50E-03 1.74% 3.44E-03 3.00% 0.983 0.034 -0.5 244.7 2.18E-03 2.21% 2.15E-03 3.00% 0.988 0.037 -0.3 344.3 1.56E-03 2.49% 1.54E-03 3.00% 0.988 0.039 -0.3 778.9 7.06E-04 2.07% 6.99E-04 3.00% 0.990 0.036 -0.3 1112.1 5.07E-04 1.92% 5.06E-04 3.00% 0.999 0.036 0.0 1408.0 4.08E-04 1.82% 4.10E-04 3.00% 1.004 0.035 0.1 Weighted Average 0.996 0.013 Table A1.3b.

241Am-152 Eu point source at 90 degrees: Comparison of ISOCS vs. Measured Efficiencies.

Source located at 90 degrees Measured Efficiency ISOCS Efficiency Ratio of ISOCS eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Eu-152 39.9 1.54E-05 5.86% 1.51E-05 25.00% 0.983 0.252 -0.1 Am-241 59.5 1.66E-04 1.09% 1.73E-04 12.00% 1.045 0.126 0.4 Eu-152 121.8 9.68E-04 0.82% 9.39E-04 8.00% 0.970 0.078 -0.4 244.7 9.19E-04 1.19% 8.89E-04 8.00% 0.966 0.078 -0.4 344.3 7.49E-04 1.03% 7.19E-04 5.00% 0.960 0.049 -0.8 778.9 4.24E-04 1.06% 4.07E-04 5.00% 0.962 0.049 -0.8 1112.1 3.31E-04 1.01% 3.23E-04 5.00% 0.978 0.050 -0.4 1408.0 2.82E-04 0.92% 2.76E-04 5.00% 0.980 0.050 -0.4 Weighted Average 0.972 0.022 Table A1.3c.

241Am-152 Eu point source at 135 degrees: Comparison of ISOCS vs. Measured Efficiencies.

Source located at 135 degrees Measured Efficiency ISOCS Efficiency Ratio of ISOCS eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 59.5 6.11E-05 5.75% 6.10E-05 18.00% 1.000 0.189 0.0 Eu-152 121.8 1.11E-03 2.46% 1.07E-03 12.00% 0.965 0.118 -0.3 244.7 1.14E-03 3.51% 1.11E-03 12.00% 0.968 0.121 -0.3 344.3 9.08E-04 3.07% 8.87E-04 12.00% 0.976 0.121 -0.2 778.9 4.89E-04 3.08% 4.85E-04 8.00% 0.991 0.085 -0.1 1112.1 3.74E-04 2.97% 3.74E-04 8.00% 1.002 0.086 0.0 1408.0 3.16E-04 2.73% 3.14E-04 8.00% 0.994 0.084 -0.1 Weighted Average 0.988 0.039 Page 29 of 44 Table A1.3d.

241Am-137 Cs point source on end cap: Comparison of ISOCS vs. Measured Efficiencies.

Source located at 0 degrees Measured Efficiency ISOCS Efficiency Ratio of ISOCS eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 6.30E-02 7.80% 7.00E-02 20.00% 1.111 0.239 0.5 17.8 1.29E-01 7.78% 1.40E-01 20.00% 1.085 0.217 0.4 26.3 2.09E-01 7.87% 2.27E-01 20.00% 1.083 0.217 0.4 59.5 2.79E-01 3.35% 2.83E-01 5.00% 1.016 0.051 0.3 Cs-137 661.7 6.88E-02 3.52% 6.75E-02 5.00% 0.981 0.049 -0.4 Weighted Average 1.004 0.034 Table A1.3e.

241Am-137Cs point source at 10.4cm from end cap: Comparison of ISOCS vs. Measured Efficiencies. Source located at 0 degrees Measured Efficiency ISOCS Efficiency Ratio of ISOCS eff. over Measured eff. Nuclide E (keV) Efficiency 1 sd % Efficiency 1 sd % Ratio 1 error Dev./ Am-241 13.9 4.04E-03 7.30% 4.14E-03 20.00% 1.025 0.218 0.1 17.8 9.93E-03 7.25% 9.66E-03 20.00% 0.972 0.207 -0.1 26.3 1.67E-02 7.46% 1.65E-02 20.00% 0.988 0.211 -0.1 59.5 2.07E-02 1.73% 2.06E-02 4.00% 0.994 0.043 -0.1 Cs-137 661.7 4.69E-03 2.04% 4.77E-03 4.00% 1.017 0.046 0.4 Weighted Average 1.004 0.030 Page 30 of 44 The relative efficiency (1332 keV from 60Co at 25 cm) was calculated using the ISOCS characterization for the detector S/N 13218 and compared against the value measured during the characterization measurements. The relative efficiency measurement is not use directly in the characterization procedure. Therefore, this measurement is intended to serve as an independent verification of the ISOCS characterization of the detector. It should be noted that the relative efficiency on the detector specification sheet is meant to be a guaranteed minimum value for the specific detector. Therefore, the ISOCS calculated relative efficiency is typically higher than the guaranteed minimum value. The ISOCS efficiency, taken with a 1 uncertainty estimate of 4%, can be construed to be a more representative efficiency value for the detector.

Table A1.4. The relative efficiency: Comparison of ISOCS vs. the nominal value. Efficiency Nominal 50.79% ISOCS 50.88% Ratio 1.002 The baseline ISOXSRCE Detector Characterization Check Source measurements are presented in the following two tables, if the ISOXSRCE was included as part of the ISOCS/LabSOCS characterization. Please note that the ISOXSRCE check source is included by default, unless specifically requested to be excluded from the characterization at the time of order. Details on the check source measurements and their usage are presented in Appendix E. Table A1.5a. ISOXSRCE base line measurement data (on end).

Measurement date Energy (keV) FWHM (keV) Centroid (channel) Peak count rate (cps)

% 1 uncertainty 12/02/2017 42.8 0.75 478.06 181.33 2.89% 60.0 0.73 669.47 11.59 2.10% 86.5 0.80 964.18 312.30 1.51% 105.3 0.80 1172.51 208.86 1.51% 511.0 2.42 5677.65 463.26 3.32% 1274.5 1.66 14156.60 105.08 1.52% Table A1.5b. ISOXSRCE base line measurement data (on side). Measurement date Energy (keV) Peak count rates in azimuthal directions Count rate @ 0 deg Count rate @ 120 deg Count rate @ 240 deg 12/02/2017 cps % 1Unc cps % 1Unc cps % 1Unc 42.8 0.90 6.31% 0.64 9.19% 0.83 15.76% 60.0 0.53 21.69% 0.45 18.70% 0.55 16.96% 86.5 38.81 1.59% 38.55 1.60% 38.97 1.58% 105.3 36.55 1.59% 36.36 1.59% 36.83 1.59% 511.0 185.11 3.32% 187.72 3.32% 187.63 3.32% 1274.5 52.52 1.54% 53.29 1.54% 53.29 1.54% ISOXSRCE serial number: 82217-8 Page 31 of 44 B. Energy/Shape Calibrations and Hardware Settings Energy and Shape calibrations were performed by acquiring a gamma ray spectrum using a NIST traceable mixed gamma point source containing 241Am and 152Eu. The pole-zero setting was adjusted to yield an optimum pulse shape. The gain and the zero of the spectrum were adjusted to give, approximately, a slope of 0.09 keV/channel and an intercept of 0.0. The energy and Full Width Half Maximum calibrations were performed.

The details of these and a ll hardware settings are pr esented in this appendix.

0500100015000400080001200016000Energy (keV)Channel Energy CalibrationMeasured PointsFit Function0.51.01.52.0 2.5050010001500FWHM (keV)Energy (keV)Shape CalibrationMeasured PointsFit Function Page 32 of 44

Energy Calibration Report 12/12/2017 1:28:20 PM Page 1

• • • • • E N E R G Y C A L I B R A T I O N R E P O R T *****

Detector Name: 5524

Sample Title: SN13218_0D

• • • • • • • • • • • • • ENERGY CALIBRATION COEFFICIENTS *************

Energy Calibrate Performed on: 12/1/2017 7:56:07 AM

by:

Energy Calibrate Type: POLY

Energy(keV) = -0.278 + 0.090*ch + 0.00E+000*ch^2 + 0.00E+000*ch^3

• • • • • • • • • • • • • SHAPE CALIBRATION COEFFICIENTS *************

Shape Calibrate Performed on: 12/1/2017 7:56:07 AM

by:

FWHM = 0.542 + 0.028*E^1/2

LOW TAIL = 9.6E-001 + 3.9E-004*E

• • • • • • • • • • • • • ENERGY CALIBRATION RESULTS TABLE *************

Centroid Centroid Energy

Channel error (keV )

156.27 0.03 13.90 295.36 0.03 26.34

664.39 0.01 59.54

1355.54 0.04 121.78

3825.53 0.01 344.28

8653.64 0.05 778.90

12354.14 0.08 1112.07

15640.12 0.08 1408.01

• • • • • • • • • • • • • SHAPE CALIBRATION RESULTS TABLE *************

Energy FWHM FWHM TAIL TAIL (keV ) channels error channels error 13.90 8.08 0.06 10.84 1.00

26.34 7.93 0.06 7.72 1.51

59.54 8.37 0.01 12.39 1.00

121.78 9.17 0.07 11.24 1.00

344.28 11.45 0.03 12.22 0.59

778.90 15.07 0.10 17.04 4.01

1112.07 17.55 0.16 14.04 0.92

1408.01 19.55 0.14 19.19 1.48

Page 33 of 44

• • F R O N T E N D H A R D W A R E S E T T I N G S R E P O R T **

Report Generated On  : 12/12/2017 2:00:48 PM

Sample Title  : SN13218_0D Sample Identification  : 11-31

Sample Type  :

Sample Geometry  :

Sample Taken On  :

Acquisition Started  : 12/1/2017 9:44:05 AM

Live Time  : 3600.0 seconds

Real Time  : 3777.9 seconds

=================================================

MCA: Type: Lynx Serial No: 13000005

---

Amplifier: Type: LYNX Serial No:

---

Composite Gain: 10.00 Shaping Mode:

Coarse Gain: 5.66 BLR Mode: Auto

Fine Gain: 1.08 LTC Mode: On

Super-fine Gain: 1.00 Input Mode: Normal

Pole Zero Value: 2174 Input Polarity: Neg

Shaping Time: 0.00 Inhibit Polarity: Pos Pileup Rejection: Off

HVPS: Type: Internal Serial No: 13000005

---

Voltage: 3101.00 Overload Latch: Disable

Voltage Limit: 5000.00 Inhibit Latch: Disable

Inhibit Signal: 5V

Voltage Range: 5000.00 Output Polarity: Pos

Dig.Stabliz Type: Internal Serial No: 13000005

---

Window 1 Window 2

Analog Range: 0.00 0.00

Analog Mode: Off Off

Stabilizer Centroid: 200 10

Stabilizer Range: 5 4

Stabilizer Spacing: 4 10

Stabilizer Rate: 0.00 0.00

Correction Factor: 2048.00 0.00

Event Multiplier: 1 1

Use NaI Range: No No

Zero Overrange: No Gain Overrange: No

DSP Gain Type: Internal Serial No: 13000005 Page 34 of 44

---

Coarse gain 5.6600E+000

Fine gain 1.0814E+000

S-fine gain 1.0000E+000

Amp gain 1.0000E+001

Conv. gain 0

Range 32768 Offset -5 LLD 1.0000E-001

Zero 0.0000E+000

FDisc Mode Auto

FDisc Setting 1.0000E+000

Inp. Polarity 1

Inh. polarity 0

LTC mode On

Coinc. mode 0

PUR Guard 1.1000E+000

Inhibit Mode 0

LT Trim 500

ICR 3.3950E+003

DSP Filter Type: Internal Serial No: 13000005

---

Rise Time 1.0400E+001

Flat Top 1.2000E+000

BLR mode Auto

Preamp type RC

Pole zero 2174

=================================================

Page 35 of 44 C. Calibration Source Certificates Page 36 of 44

-Eckert & Ziegler 24937 Avenue Tibbitts Va l encia , Ca l ifornia 91355 l lsoto p e Produ cts Tel 661*309*1010 Fax 66 1 *257*8303 CERTIFIC ATE OF C A L IBRATION MIXED GAM MA S T ANDARD SOUR CE 11

• Radionuclide:

Am-241 Radionuclide:

Eu-152 Customer:

P.O.No.: CANBERRA IN DUSTRIE S (CONNECT 1cun 4037486 Catalog No.: Ha l f-lifc (Am-241):

432.17 :!: 0.66 years Half-lilfc (Eu-152):

4933 :t 11 days Rcfcrence Date: Contained Radioactivit y: Am-241: 3.958 Eu-152: 4.113 Pb ysica l Oe sc r iption: µCi , 146.4 µCi , 152.2 Source No.: kBq kBq A. Capsule type: B. Nature of active deposit:

C. Active diame ter/vo l ume: C (11 mm x 23.5 mm) Evapo rated metallic salts 3mm D. Backing: Epoxy E. Cover: Plastic Radioimpurities:

Am-241: None detected Eu-1 52: Gd-153 = 1.40% on 1-Nov-11 Metb od of Calibration:

This so urce was assayed using gamma ra y spectrometry. Am-241: Eu-1 52: 59.5 keV 344.3 keV Uncertainty of Measurement:

A. Type A (random) unce rta inty: B. Type B (systematic) uncertainty:

C. Uncerta i nty in aliquot weigh i ng: D. Total uncerta in ty a*t the 99% confidence I evel: Notcs: :!: +/- +/- +/- -See reverse side fo r lea k test (s) performed on th i s source. GF-CUSTOM 1-Nov-1 1 12: 00 PST 14-621 Total Activity: 8.071 µCi, 298.6 kBq 0.360 gammas per decay 0.266 gammas per decay Am-241 Eu-152 0.6 % t 0.8 % 3.0 % :!: 3.0 % 0.0 % +/- 0.0 % 3.1 % +/- 3.1 % -EZIP participates in a NIST measurement ass ur ance prog ram to establish and ma in tain imp licit traceabil i ty for a number of nuc l ides , based on the b lin d assay (and late r NIST certification) of Standard Reference Materials (as i n NRC Regulatory Guide 4.15). -Nuclea r dala was taken from IAEA-TECDOC-619 , 199 1. y~~Jk.Da~

Quality Contro l 11:jrpr-n Re1ssued EZIP Ref. No.: 1531-7 9 ------------------

IS09 001 CERTIF I EO -----------

---

M*dkal lm a glng Laboratory Jndust rial Gauging Laboratory 24937 Avenue T t bbltts V a l encia, Cal i forn i a 9 1 3SS 1800 No rth Ke y stone Street B ur ban k ,Californi a 91504 Page 37 of 44

-. Eckert&Z1egler l sotope P roduc t s 24937 Avenue Tibbitts Valencia, California 91355 Tel 661*309*1 010 Fax 661 *257*8303 CERTIFICA TE OF CALIBRA TION MIXED GAMMA STANDARD SOURCE 11

• Radioauclide:

Am-241 Radionuclide:

Cs-137 Custo m er: P.0.No.: CANBERRA INOUSTR I ES (CONNECTICUT) 4037486 Catalog No.: Ha l f-life (Am-241):

432.17 :!: 0.66 years Half-life (Cs-1 37): 30.17 +/- 0.16 years Reference Date: Contai.ned Radioactivity:

Am-241: 0.5346 Cs-137: 0.5307 Physical D escrip t ion: µCi, 19.78 µCi, 19.64 Source No.: kBq kBq A. Capsu l e type: B. Nature of active deposit: C. Active diameter/vo lu me: C(11 mmx23.5mm)

Evaporated metallic salts 3mm D. Back i ng: Epoxy E. Cover: Plastic Radioimpu riti es: None detected Method ofCal i bration: This source was assayed using gamma ray spectrometry.

Am-241: Cs-137: 59.5 keV 661.7 keV Uncert.ai n ty of Mcasurernent:

A. Type A (random) uncertainty:

B. Type B (systemat i c) uncertainty

C. Uncertainty in al i quot weighing:

D. Total uncertainty ai the 99% confidence Ievel: Notes: +/- +/- +/- +/- GF-CUSTOM 1-Nov-11 12:00 PST 14-614 Tota l Activ i ty: 1.065 µCi, 39.41 0.360 gammas pe r decay 0.851 gammas per decay Am-241 Cs-137 0.6 % :!: 0.7 % 3.0 % +/- 3.0 % 00 % +/- 0.0 % 3.1 % +/- 3.1 % -See reverse side for leak test(s) performed on this source. kB q -EZIP part i cipates in a NIST measurement assurance program to establish and ma i nta i n i mplicit traceab i l ity for a number of nuclides, based on the bllnd assay (and later NIST certification) of Standard Reference Materia l s (as i n NRC Regulatory Gu i de 4.1 5). -Nuclear data was taken from IAEA-TECDOC-619 , 1991.

Re ssued EZIP Ref. No.: 1531-79 ------------------

1$09001 CERTIF IEO ------------------

Med i cal lmaging L ab oratory lndustri*I Gauging L a bor a tory 2 4937 Aven u~ Tibbilts Va l enc i a, Ca l i fo r nla 9 1 355 1800 Notth Key s tone S tree t Burbank,Ca li forn i a '91504 Page 38 of 44

Page 39 of 44 D. ISOXSRCE Measurements The model ISOXSRCE Detector Characterization Check Source is used to track the relative changes in detector efficiency for quality assurance purposes. The data from measurements with this source can also be used by Canberra to determine the current dead layer thickness of the detector crystal as well as for updating the detector characterization parameters. Please note that the ISOXSRCE check source is included by default with an ISOCS/LabSOCS characteri zation, unless specifically requested to be excluded from the characterization at the time of order.

The check source is uncalibrated, and contains the isotopes 155Eu (86.5 keV and 105.3 keV) and 22Na (511 keV and 1275 keV) at approximately 1 Ci each. The source is permanently attached to a holder jig, and includes a Velcro strap to mount the source/jig onto the detector endcap. The ISOXSRCE Check Source Fixture User's Manual presents full documentation of the source, jig, and its intended uses.

Figure A6.1a End Measurement Figure A6.1b. Side Measurement Prior to shipment, the ISOXSRCE source was counted at Canberra' s production facility according to the instructions in the ISOXSRCE Check Source Fixture User's Manual.

One measurement was made with the source on-axis (Figure A6.1a) and three measurements were made on the sides (Figure A6.1b). The side measurements were performed with the jig fixed at presented in Tables A1.5a and A1.5b in this document. As soon as possible after the ISOCS characterized detector and the check source are received from the factory, users are strongly advised to set up the system with their own electronics and generate their own base line results for the various QC parameters. This should be done at minimum with the ISOXSRCE Check Source as described above.

Page 40 of 44 The results of these baseline measurements should not be appreciably different from those presented in Tables A1.5a and A1.5b in this document. Further details and recommendations regarding implementation of a QA program are given in Appendix E of this document.

Detector Re-Characterization:

If the quality control process indicates that the detector efficiency has changed beyond the claimed accuracy for the ISOCS/LabSOCS software, corrective action is necessary. The ISOXSRCE Check Source Fixture User's Manual recommends that corrective action should be considered if the low-energy efficiency changes by more than 7-10%, or if the high energy efficiency changes by more than 4-5%. The user has three options for corrective action to addre ss the change in efficiency. They all i nvolve a trade-off, and the user must decide, based on their application requirements and available resources (e.g. time and backup detectors), which is the most appropriate action.

1) The simplest action is to increase the uncertainty values used in the ISOCS/LabSOCS software. Clearly this does not truly address the change in efficiency, it simply increases the overall uncertainty parameters used by the software calculations to reflect the change. This action may be acceptable if this additional uncertainty is relatively small in comparison with other uncertainties in the sample measurement process (e.g. uncertainties due to non-uniform source distribution in large containers, uncertainties in sample composition or density). This situation is more likely to be applicable to users in a large-scale decommissioning or decontamination environment than in a laboratory environment.

2) The most complete and accurate response is to send the detector back to Canberra's production facility for a full recharacteriz ation (Canberra model ISOXCALU). A full recharacterization ensures that all aspects of the detector's efficiency response are incorporated into a new characterization, hence this is the recommended action if the maximum accuracy is required. However, it does entail being without the use of the detector for approximately 4 weeks in typical cases.

3) An intermediate action is appropriate if the change in efficiencies is primarily at lower energies. Such a change indicates an increase in the detector dead layer. In this case, users can perform the ISOXSRCE measurements according to the instructions in the ISOXSRCE Check Source Fixture User's Manual, and send the data to Canberra. This data can be used at Canberra's production facility to estimate the change in dead layer thickness and to generate a new characteri zation (Canberra model ISOXCALL). Note that this does not require that the detector itself be sent in, thus there is no interruption in the user's sample measurement program.

Page 41 of 44 E. Quality Assurance and Quality Control Recommendations It is imperative that users institute and maintain a QA program to monitor all of the significant performance parameters of their detector and signal chain, and to verify that these parameters have not changed to a degree that would significantly affect the quality of the intended sample measurements. One of the most important parameters to monitor for stability is the detector efficiency. In practice, this can be monitored by tracking the net peak count rates of the ISOXSRCE source, or any suitable, user supplied check source, if the ISOXSRCE was not requested. This same source can also be used to monitor the stability of the peak shape (i.e. FWHM) and peak location (i.e. centroid channel). Canberra recommends that the following parameters be tracked via the check source measurements. Net peak count rates at gamma ray energies of 86.5 keV, 511 keV (optional) and 1275 keV; this will monitor the detector efficiency. FWHM at the above gamma ray energies; this will monitor the stability of peak shape and detector resolution Centroid channel location at the above gamma ray energies; this will monitor gain stability.

Prior to shipment, the ISOXSRCE source was counted at Canberra' s production facility according to the instructions in the ISOXSRCE Check Source Fixture User's Manual.

The values for these measurements are presented in Tables A1.5a and A1.5b in this document.

A key aspect of a good QA program is the establishment of a baseline set of measurements. Consequently, as soon as possible after the ISOCS characterized detector and the check source are received from the factory, users are strongly advised to set up the system with their own electronics and generate their own baseline results for the various QC parameters. This should be done at minimum with the ISOXSRCE Check Source as described in Appendix E of this document. The results of these baseline measurements should not be appreciably different from those presented in Tables A1.5a and A1.5b in this document. Furthermore, if other check sources are to be used as part of the QA program, these should also be measured at this time to establish a baseline as well as a cross-reference to the ISOXSRCE source, or to be used in the case where the

ISOXSRCE was not included.

For reference, the following Quality Control Recommendations are presented below, adapted from the ISOXSRCE Check Source Fixture User's Manual.

A good Quality Control (QC) program is essential for validating the system's proper performance to auditors. It is also a good source of data to help identify problems. The Page 42 of 44 Model S505 Genie 2000's Quality Assurance Software is an excellent tool to simplify and automate the collection of this data and present it in useful formats. Below are some generic guidelines to consider in setting up a program.

Quality Control Guidelines

1. Understand the system, and possible failure mechanisms. Develop a QC program that alerts the operator in the event of a failure, and creates a record for later review, which will help direct corrective action.

2. Determine the important parameters to monitor, which will generate an alarm if the parameter values exceed an Action Level. Select some additional parameters to record for periodic review, which will help diagnose the Action Level alarm. Do not set Action Levels on any of these additional parameters, although setting some of them as Investigation Levels is recommended.

3. A balanced approach should be used when setting alarm levels so as to reduce the number of false negative and false positive indications. Consider the overall uncertainty of the measurement and technique including background and environmental variability and the requirements of the application when setting Investigation or Action Levels. Setting these parameters based solely on two or three standard deviations will cause frivolous alarms.

4. Periodically review all QC data, and then revise the number of monitored parameters, and adjust the Investigat ion or Action Levels , as appropriate.

Check Source Counting A properly designed QC program will alert the user to problems concerning noise, resolution, gain, zero, non-linearity, efficiency, etc. The ISOXSRCE check source, when counted according to the procedures given in the ISOXSRCE Check Source Fixture User's Manual, provides a good stream of QC data. As discussed in this Appendix, Canberra recommends that the user monitor the net peak count rates, the FWHM, and the centroid channel location.

Collection of QC data should start immediately after the efficiency calibration of the detector or immediately after the detector has been characterized for ISOCS/LabSOCS. There should be minimal time delay between the calibration/characterization and the establishment of baseline check source data.

In day-to-day practice, the check source should be counted at the beginning of each sequence of operations in a given day, and at the end of the sequence of operations on that day. In the case of continuous operations, count once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

Set Action Levels on Activity only. If the source peak activity is normal, it would indicate that the other parameters are also adequate. Investigation Levels may be set on other parameters. Set the Investigation Level just below the point at which changes in Page 43 of 44 peak full width half maximum (FWHM) or changes in the peak energy (or centroid) could adversely change the activity.

Background Counting A properly performed background count will alert the user to extraneous or unusual activity that might affect the normal sample counts. The detector should be located in an area where the background is expected to be co nstant (e.g. inside a shielded room). In other situations like in situ counting with unshielded or partially shielded detectors, frequent background counts are not practical. However, even for in situ counting, the detector should occasionally be placed in a low and stable background environment for these background checks. The 50 mm (1.97 in.) ISOCS shield with the back shield and zero-degree collimator can produce a stable background environment suitable for this check measurement.

As with check source data, collection of background data should start immediately after the efficiency calibration of the detector or immediately after the detector has been characterized for ISOCS/LabSOCS. There should be minimal time delay between the calibration/characterization and the establishment of the background.

The following parameters should be recorded: (i) Background Count Rate for a low energy band (e.g. up to 100 keV); this will help find unusual noise that might be coming into the system. (ii) Background Count Rate for most of the spectrum (e.g. 100 - 3000 keV); this will help prove that contamination is not present; visual examination of the spectrum provides an even more sensitive check. (iii) Activity of key or important nuclides that are likely sources of contamination; this will establish that the detector and/or shield are not contaminated with those particular nuclides.

In day-to-day practice, the background should be counted at the beginning of each sequence of operations in a given day, and at the end of the sequence of operations on that day. In the case of continuous operations, count once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

Choose Action Levels for background nuclide contamination based upon counting statistics of 2 or 3 standard deviations. This assumption is valid for background counts only. Choose Investigation Levels on backgr ound count-rate careful ly, since the peak search algorithms can handle rather wi de ranges of non-peaked backgrounds.

The Final Investigation and Action Level Settings Examine the data obtained from at least one month of normal operations prior to establishing the final Investigation and Action Levels. The data should include at least 20-30 measurements that reflect the normal and full range of variable conditions. Perform a weekly review of all the data collected in order to spot trends before problems Page 44 of 44 develop. Although most if not all of the data points will be at levels below alarm levels, the weekly review is recommended to help avert problems during real counts. Review the settings of all Investigation and Action Levels on a quarterly basis and adjust accordingly.

Page 1 of 23 A part of Mirion Mirion Technologies (Canberra), Inc. 800 Research Parkway Meriden, CT 06450 Phone: 203-238-2351 Fax: 203-639-2060 Verification of the ISOCS Characterization of the Canberra LabSOCS System Canberra Sales Order #

75766 S/N 13218 December 12, 2017

ISOXVRFY Measurements Performed By: Meriden

ISOCS Data Analysis Perf ormed By:

Gabriela Ilie

Approved By:

________________

___________

David Sullivan

Page 2 of 23 Copyright 2017, Mirion Technologies (Canberra), Inc. All rights reserved. The material in this document, including all information, pictures, graphics and text, is the property of Mirion Technologies (Canberra), Inc. and is protected by U.S. copyright laws and international copyright conventions. Mirion Technologies (Canberra), expressly grants the purchaser of this product the right to copy any material in this document for the purchaser's own use, including as part of a submission to regulatory or legal authorities pursuant to the purchaser's legitimate business needs. No material in this document may be copied by any third party, or used for any commercial purpose or for any use other than that granted to the purchaser without the written permission of Mirion Technologies (Canberra), Inc. Mirion Technologies (Canberra), Inc., 800 Research Parkway, Meriden, CT 06450 Tel: 203-238-2351 FAX: 203-235-1347 http://www.canberra.com/. The information in this document describes the product as accurately as possible, but is subject to change without notice. Printed in the United States of America.

Genie, ISOCS, and LabSOCS are trademarks of of Mirion Technologies, Inc. and/or its affiliates in the United States and/or other countries.

For Technical Assistance, please call our Customer Service Hotline at 800-255-6370 or email techsupport@canberra.com

Page 3 of 23 Table of Contents 1.Verification of ISOCS Characterization (ISOXVRFY).................... 41.1Verification Tests ....................................................................................................... 41.2Verification Test Results ............................................................................................ 51.3Results Summary ....................................................................................................... 62.ISOXVRFY Measurement Results .................................................. 83.Schematic Drawings of ISOXVRFT Geometries ......................... 18A.ISOXVRFY Source Certificates .................................................... 19 Page 4 of 23 1. Verification of ISOCS Characterization (ISOXVRFY) 1.1 Verification Tests In the Factory Integration and Test report supplied with the ISOCS characterization, validation results were provided for five geometries, namely, (i) an Am-241/Eu-152 point source 29 cm away on-axis with respect to the detector, (ii) the Am-241/Eu-152 point source 31 cm away and at 90 from the axis of the detector, (iii) the Am-241/Eu-152 point source laterally 21 cm away and at 135º from the axis of the detector, (iv) an Am-241/Cs-137 point source on the endcap, and (v) the Am-241/Cs-137 point source placed a distance of 10.4 cm away from the endcap.

In this section, test results based on measurement of several additional standard source geometries are presented. The measurements were performed using the ISOCS characterized HPGe detector S/N 13218. The measurement geometries are as follows.

1. A glass fiber filter paper mounted on a Plexiglas centering plate, placed on the detector endcap (same as in the characterization measurement).

2. A 20cc acrylic cylinder with a solid resin matrix, resting on the Plexiglas centering plate, which is placed on the detector endcap.

3. A 400ml polypropylene container with a solid resin matrix, resting on the Plexiglas centering plate, which is placed on the detector endcap.

4. A 2.8-liter Marinelli beaker with a solid resin matrix, centered on the detector endcap. 5. The glass fiber filter paper at a distance of 10.17cm from the detector endcap (same as in the characterization measurement).

6. The 20cc acrylic cylinder at a distance of 10.17cm from the detector end cap.

7. The 400ml polypropylene container at a distance of 10.17cm from the detector endcap.

Refer to the attached schematic diagrams of the measurement geometries.

Each source is a multi-nuclide gamma ray standard, emitting gamma rays in the energy range from 59.5 keV (Am-241) to 1836 keV (Y-88). The measurements are performed in a shielded area, not influenced by other sources. Dedicated electronics and computer are used in acquiring data.

Page 5 of 23 1.2 Verification Test Results The results for each of the seven verification tests are given in Tables 1 through 7 that are attached to this report. In each case, a brief description of the source-detector geometry is given at the top. Columns 1 and 2 of each table give the name of the nuclide and the energy of the gamma ray peak being measured. Column 3 gives the measured activity in units of gammas/sec, obtained using the measured peak area and the LabSOCS efficiency at the given energy. Column 4 gives the relative uncertainty (1) due to counting statistics and LabSOCS uncertainties. Columns 5 gives the true activity of the nuclides in units of gammas/sec at the source calibration date given in the certificate. Column 6 gives the true activity of the nuclides, decay corrected until the measurement date. Column 7 of each table gives the uncertainty (1) in the source activity. Column 8 gives the ratio of measured to true activity for each nuclide, and column 9 gives uncertainty in the measured/true ratio. Column 8 in Tables 1 through 7 specifies the expected uncertainty in the LabSOCS efficiencies. The expected uncertainty values for the LabSOCS efficiencies have been derived based on the results of approximately 50 validation tests performed by Canberra Industries using similar laboratory sources on a variety of detectors. For details on these validation tests, refer to the document titled "Validation and Internal Consistency Testing of ISOCS Efficiency Calibration" published by Canberra. The final column (COI value) shows the computed cascade summing correction values. These values are used to produce the sum-loss corrected activities in Column 3. The cascade summing effects are described in more detail below.

In addition to the tables, Figures 1-7 present the measured/true activity ratio versus energy for each verification test. The plot s have been appended to this report.

It should be noted that for close-in geometries, the measured activities of Co-60, Y-88, and in some cases, Ce-139 and Co-57, are lower than their true activities. This is because of gamma ray cascade summing (or true coincidence summing) losses in these nuclide measurements. The severity of cascade summing losses is dependent upon the decay scheme of a given nuclide and the total efficiency of the measurement geometry. The higher the total efficiency, the greater is the loss due to cascade summing. In other words, cascade summing losses will be more severe at smaller source-detector distances and with larger detectors.

The standard sources used in the verification tests contain Ce-139, a nuclide whose gamma rays exhibit true coincidence summing. The energy of the principal gamma ray emitted from the decay of Ce-139 is 165 keV. This gamma ray undergoes true coincidence summing with low energy X-rays emitted from Ce-139. Therefore, true coincidence summing losses for Ce-139 are observable primarily in the case of measurements with BEGe, LEGe, REGe, and Xtra detectors, owing to the absence of dead germanium layer in the front. The 122 keV line from Co-57 is emitted about 10%

of the time in cascade with a 14 keV gamma-ray. This causes a typically minor summing loss to the 122 keV line. The two lines listed in the tables for Co-60 (1173 and 1332 keV) emitted simultaneously per decay nearly 100% of the time. The similar is true for the two lines of Y-88 (898 and 1896 keV) at about 94% of the time.

Consequently, in the Page 6 of 23 lines from Co-60 and Y-88 will shows typically significant losses in close geometries for all detector types.

With the release of Genie2k version 3.2 software, it is possible to automatically perform cascade summing corrections for ISOCS characterized detectors. Previous versions of Genie2k required a peak-to-total calibration using additional sources. With the current release of Genie2k total efficiencies are computed based on the ISOCS characterization efficiency. In this report we have utilized the cascade summing correction algorithm to perform corrections for measured activities in the different source geometries (Note: only Co-57, Ce-139, Co-60, and Y-88 require corrections). The measured activities are corrected by dividing by the cascad e summing correcti on (COI) value. 1.3 Results Summary A summary of the verification test results is presented in the following table. The results for each geometry are grouped into three energy regimes; (i) less than 150 keV, (ii) 150-400 keV and (iii) greater than 400 keV. For each energy regime, the following results are presented.

1. For nuclides within a given energy range, the weighted average value of the measured to true activity ratio is calculated. The ratios are weighted by the inverse of their squared uncertainties (1/ 2). For close-in geometries, nuclides exhibiting true coincidence losses are not included in the weighted average calculations.

2. The bias in the ISOCS efficiency of this detector is obtained by calculating the deviation of the average value of the ratio from its true mean, the true mean being unity. For close-in geometries, nuclides exhibiting cascade summi ng are not included.

3. The estimated uncertainty in LabSOCS efficiencies, derived from Canberra's validation test database, for a group of detectors.

4. The weighted average value of the measured to true activity ratio for a given energy range, computed by pooling together the ratios from all seven geometries.

5. The standard deviation of the ratios for a given energy range, computed by pooling together the ratios from all seven geometries.

6. The average uncertainty in LabSOCS efficiencies for this specific detector, computed as the difference between the standard deviation of the ratios and the measurement uncertainties.

7. The LabSOCS uncertainty for this detector is calculated in the same manner as described in the Validation and Internal Consistency document For a given source geometry, if the observed bias is less than twice the assigned 1 uncertainty for LabSOCS, then the characterization for the detector is within the tolerance limits at the 95% confidence level. If the observed bias is larger than twice the assigned 1 LabSOCS uncertainty for a given geometry, the ISOXVRFY data forewarns the user that the results of their sample measurements in the given geometry may have a bias for those energies and geometries.

Page 7 of 23 ISOXVRFY Geometry Data < 150 keV Data 150 - 400 keV Data > 400 keV Meas/True Ratio (avg) Bias LabSOCS Unc (1) Meas/True Ratio (avg)Bias LabSOCS Unc (1) Meas/True Ratio (avg)Bias LabSOCS Unc (1) Filter Paper (close) 1.01 0.82% 7.0% 1.01 0.53% 6.0% 1.02 2.17% 4.3% Filter Paper (far) 1.04 3.63% 7.0% 1.00 -0.47% 6.0% 1.00 0.39% 4.3% 20 ml Cyl. (close) 1.02 2.04% 7.0% 1.00 0.05% 6.0% 1.00 0.43% 4.3% 20 ml Cyl. (far) 1.03 2.78% 7.0% 1.01 1.36% 6.0% 1.00 0.32% 4.3% 400 ml Cyl. (close) 1.03 2.65% 7.0% 0.99 -0.88% 6.0% 1.01 0.99% 4.3% 400 ml Cyl. (far) 1.01 1.20% 7.0% 1.02 1.91% 6.0% 0.99 -0.60% 4.3% Marinelli 1.05 4.65% 7.0% 1.06 6.04% 6.0% 1.05 5.05% 4.3% Average (all) 1.03 1.01 1.01  % Std. Dev. 1.56% 2.59% 2.22%

Average bias 2.54% 1.61% 1.42% LabSOCS Unc. 8.85% 9.93% 4.04%

Page 8 of 23 2. ISOXVRFY Measurement Results

Table 1. Glass Fiber Filter (48 mm diameter) in contact with Detector Endcap

==

Description:==

This is a Glass Fiber Filter resti ng on the endcap of the detector. The pre-defined beaker file used in the LabSOCS calculations is FILTER.BKR. The diameter of the source matrix us ed in LabSOCS calculations is 48 mm.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 1251.4 9.06% 1251.0 1250.1 1.80% 1.00 9.06% 7.00% 1.00 Cd-109 88 690.8 9.45% 857.1 678.2 2.05% 1.02 9.45% 7.00% 1.00 Co-57 122 309.1 9.06% 457.3 307.3 1.70% 1.01 9.06% 7.00% 0.98 Ce-139 166 294.7 14.67% 637.0 290.6 1.80% 1.01 14.67% 6.00% 0.79 Sn-113 392 351.4 7.50% 895.3 350.3 1.95% 1.00 7.50% 6.00% 1.00 Cs-137 662 557.7 4.61% 562.6 557.1 2.05% 1.00 4.61% 4.30% 1.00 Mn-54 835 1776.6 4.59% 2483.0 1756.7 1.65% 1.01 4.59% 4.30% 1.00 Y-88 898 822.3 4.63% 2150.0 780.7 1.85% 1.05 4.63% 4.30% 0.74 Zn-65 1115 1634.0 4.61% 2477.0 1590.9 1.75% 1.03 4.61% 4.30% 1.00 Co-60 1173 1046.7 4.59% 1089.0 1029.6 1.95% 1.02 4.59% 4.30% 0.81 Co-60 1332 1050.2 4.59% 1090.0 1030.5 1.95% 1.02 4.59% 4.30% 0.80 Y-88 1836 845.9 4.63% 2276.0 826.4 1.85% 1.02 4.63% 4.30% 0.73

Page 10 of 23 Table 2. Glass Fiber Filter (48 mm diameter) 10.17 cm away from the Detector Endcap

==

Description:==

This is a Glass Fiber Filter resting at a height 10.17 cm above the detector endcap. The pre-defined beaker file used in the LabSOCS calculations is FILTER.BKR. The diameter of the source matrix us ed in LabSOCS calculations is 48 mm.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 1282.5 9.07% 1251.0 1250.1 1.80% 1.03 9.07% 7.00% 1.00 Cd-109 88 707.3 9.48% 857.1 678.2 2.05% 1.04 9.48% 7.00% 1.00 Co-57 122 319.7 9.19% 457.3 307.3 1.70% 1.04 9.19% 7.00% 1.00 Ce-139 166 295.7 12.74% 637.0 290.5 1.80% 1.02 12.74% 6.00% 0.98 Sn-113 392 345.6 7.76% 895.3 350.2 1.95% 0.99 7.76% 6.00% 1.00 Cs-137 662 557.4 4.91% 562.6 557.1 2.05% 1.00 4.91% 4.30% 1.00 Mn-54 835 1765.5 4.66% 2483.0 1756.4 1.65% 1.01 4.66% 4.30% 1.00 Y-88 898 789.8 4.89% 2150.0 780.3 1.85% 1.01 4.89% 4.30% 0.98 Zn-65 1115 1630.4 4.66% 2477.0 1590.5 1.75% 1.03 4.66% 4.30% 1.00 Co-60 1173 1022.9 4.77% 1089.0 1029.6 1.95% 0.99 4.77% 4.30% 0.98 Co-60 1332 1034.5 4.79% 1090.0 1030.5 1.95% 1.00 4.79% 4.30% 0.98 Y-88 1836 814.2 4.83% 2276.0 826.0 1.85% 0.99 4.83% 4.30% 0.98

Page 11 of 23 Table 3. 20 ml Acrylic Cylinder (1.

17 g/cc) on the Detector Endcap

==

Description:==

This is a 20 ml acrylic cylinder with 1.17 g/cc active matrix resting on a 0.3175 cm th ick plexiglass centering plate. The ple xiglass plate is on top of the detector endcap.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 2646.0 9.06% 2594.0 2592.2 1.80% 1.02 9.06% 7.00% 1.00 Cd-109 88 1448.1 9.45% 1777.0 1405.6 2.05% 1.03 9.45% 7.00% 1.00 Co-57 122 643.6 9.06% 947.9 636.6 1.70% 1.01 9.06% 7.00% 1.00 Ce-139 166 591.8 13.49% 1320.0 601.4 1.80% 0.98 13.49% 6.00% 0.89 Sn-113 392 729.2 7.50% 1856.0 725.2 1.95% 1.01 7.50% 6.00% 1.00 Cs-137 662 1141.6 4.61% 1166.0 1154.6 2.05% 0.99 4.61% 4.30% 1.00 Mn-54 835 3663.6 4.59% 5145.0 3638.0 1.65% 1.01 4.59% 4.30% 1.00 Y-88 898 1634.2 4.62% 4456.0 1615.3 1.85% 1.01 4.62% 4.30% 0.88 Zn-65 1115 3390.1 4.61% 5134.0 3294.9 1.75% 1.03 4.61% 4.30% 1.00 Co-60 1173 2146.8 4.60% 2257.0 2133.7 1.95% 1.01 4.60% 4.30% 0.89 Co-60 1332 2136.0 4.60% 2260.0 2136.5 1.95% 1.00 4.60% 4.30% 0.88 Y-88 1836 1689.4 4.62% 4717.0 1709.9 1.85% 0.99 4.62% 4.30% 0.87

Page 12 of 23 Table 4. 20 ml Acrylic Cylinder (1.17 g/cc) 10.17 cm from the Detector Endcap

==

Description:==

This is a 20 ml acrylic cylinder with 1.17 g/cc active matrix resting on a 10.17 cm ta ll cylindrical plexiglass spacer. The plexiglass plate is on top of the detector endcap and centered.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 2640.9 9.07% 2594.0 2592.2 1.80% 1.02 9.07% 7.00% 1.00 Cd-109 88 1462.8 9.48% 1777.0 1405.5 2.05% 1.04 9.48% 7.00% 1.00 Co-57 122 652.3 9.16% 947.9 636.5 1.70% 1.02 9.16% 7.00% 1.00 Ce-139 166 613.8 12.66% 1320.0 601.2 1.80% 1.02 12.66% 6.00% 0.99 Sn-113 392 732.9 7.67% 1856.0 724.9 1.95% 1.01 7.67% 6.00% 1.00 Cs-137 662 1126.7 4.82% 1166.0 1154.6 2.05% 0.98 4.82% 4.30% 1.00 Mn-54 835 3703.1 4.63% 5145.0 3637.6 1.65% 1.02 4.63% 4.30% 1.00 Y-88 898 1640.0 4.80% 4456.0 1614.7 1.85% 1.02 4.80% 4.30% 0.99 Zn-65 1115 3374.9 4.64% 5134.0 3294.4 1.75% 1.02 4.64% 4.30% 1.00 Co-60 1173 2121.6 4.72% 2257.0 2133.6 1.95% 0.99 4.72% 4.30% 0.99 Co-60 1332 2148.3 4.69% 2260.0 2136.5 1.95% 1.01 4.69% 4.30% 0.99 Y-88 1836 1685.6 4.76% 4717.0 1709.3 1.85% 0.99 4.76% 4.30% 0.99

Page 13 of 23 Table 5. 400 ml Acrylic Cylinder (1.17 g/cc) on the Detector Endcap

==

Description:==

This is a 400 ml acrylic cylinder with 1.17 g/cc active matrix resting on a 0.3175 cm thick plexig lass centering plate. The plexiglass plate is on top of the detector endcap.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 5212.4 9.06% 5040.0 5036.5 1.80% 1.03 9.06% 7.00% 1.00 Cd-109 88 2826.4 9.45% 3452.0 2730.2 2.05% 1.04 9.45% 7.00% 1.00 Co-57 122 1249.2 9.07% 1842.0 1236.7 1.70% 1.01 9.07% 7.00% 1.00 Ce-139 166 1183.2 13.38% 2565.0 1168.1 1.80% 1.01 13.38% 6.00% 0.90 Sn-113 392 1386.1 7.51% 3606.0 1408.1 1.95% 0.98 7.51% 6.00% 1.00 Cs-137 662 2215.7 4.61% 2266.0 2243.8 2.05% 0.99 4.61% 4.30% 1.00 Mn-54 835 7125.5 4.59% 9997.0 7067.3 1.65% 1.01 4.59% 4.30% 1.00 Y-88 898 3196.7 4.62% 8657.0 3136.2 1.85% 1.02 4.62% 4.30% 0.90 Zn-65 1115 6538.7 4.61% 9976.0 6400.7 1.75% 1.02 4.61% 4.30% 1.00 Co-60 1173 4206.5 4.59% 4385.0 4145.2 1.95% 1.01 4.59% 4.30% 0.91 Co-60 1332 4207.5 4.59% 4391.0 4150.9 1.95% 1.01 4.59% 4.30% 0.90 Y-88 1836 3334.8 4.61% 9165.0 3320.2 1.85% 1.00 4.61% 4.30% 0.89

Page 14 of 23 Table 6. 400 ml Acrylic Cylinder (1.17 g/cc) 10.17 cm from the Detector Endcap

==

Description:==

This is a 400 ml acrylic cylinder with 1.17 g/cc active matrix resting on a 10.17 cm tall cylindrical plexiglass spacer. The plexiglass plate is on top of the detector endcap and centered.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 5087.7 9.07% 5040.0 5036.5 1.80% 1.01 9.07% 7.00% 1.00 Cd-109 88 2799.2 9.47% 3452.0 2729.9 2.05% 1.03 9.47% 7.00% 1.00 Co-57 122 1238.2 9.14% 1842.0 1236.5 1.70% 1.00 9.14% 7.00% 1.00 Ce-139 166 1161.7 12.65% 2565.0 1167.7 1.80% 0.99 12.65% 6.00% 0.99 Sn-113 392 1446.8 7.62% 3606.0 1407.5 1.95% 1.03 7.62% 6.00% 1.00 Cs-137 662 2202.7 4.75% 2266.0 2243.8 2.05% 0.98 4.75% 4.30% 1.00 Mn-54 835 7100.7 4.62% 9997.0 7066.3 1.65% 1.00 4.62% 4.30% 1.00 Y-88 898 3132.4 4.75% 8657.0 3134.9 1.85% 1.00 4.75% 4.30% 0.99 Zn-65 1115 6430.3 4.65% 9976.0 6399.5 1.75% 1.00 4.65% 4.30% 1.00 Co-60 1173 4106.4 4.66% 4385.0 4145.2 1.95% 0.99 4.66% 4.30% 0.99 Co-60 1332 4172.3 4.66% 4391.0 4150.8 1.95% 1.01 4.66% 4.30% 0.99 Y-88 1836 3222.0 4.72% 9165.0 3318.9 1.85% 0.97 4.72% 4.30% 0.99

Page 15 of 23 Table 7. 2.8 l Marinelli Beaker (1.17 g/cc) on the Detector Endcap

==

Description:==

This is a 2.8 l Marinelli beaker with 1.17 g/cc active matrix resti ng on the endcap of the detector.

Nuclide Energy (keV) Meas. Activity (LabSOCS eff) gammas/s Statistical uncertainty (1) True Activity 7/1/2017 gammas/s True Activity 12/4/2017 gammas/s Source uncertainty (1) Meas./True Rel. uncert. (1) Specified LabSOCS Uncert. COI value Am-241 59.5 5503.5 9.06% 5310.0 5306.4 1.80% 1.04 9.06% 7.00% 1.00 Cd-109 88 3008.3 9.46% 3636.0 2875.2 2.05% 1.05 9.46% 7.00% 1.00 Co-57 122 1375.3 9.08% 1940.0 1302.1 1.70% 1.06 9.08% 7.00% 1.00 Ce-139 166 1320.4 12.96% 2702.0 1229.7 1.80% 1.07 12.96% 6.00% 0.95 Sn-113 392 1565.0 7.52% 3798.0 1482.0 1.95% 1.06 7.52% 6.00% 1.00 Cs-137 662 2474.3 4.63% 2387.0 2363.6 2.05% 1.05 4.63% 4.30% 1.00 Mn-54 835 7892.5 4.59% 10530.0 7442.2 1.70% 1.06 4.59% 4.30% 1.00 Y-88 898 3518.8 4.63% 9119.0 3301.0 1.85% 1.07 4.63% 4.30% 0.94 Zn-65 1115 7168.1 4.61% 10510.0 6741.0 1.75% 1.06 4.61% 4.30% 1.00 Co-60 1173 4581.1 4.60% 4619.0 4366.3 1.95% 1.05 4.60% 4.30% 0.94 Co-60 1332 4547.3 4.60% 4625.0 4371.9 1.95% 1.04 4.60% 4.30% 0.94 Y-88 1836 3590.8 4.62% 9654.0 3494.7 1.85% 1.03 4.62% 4.30% 0.93 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 1. Glass Fiber Filter Paper on Endcap 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 2. Glass Fiber Filter Paper at 10.17 cm 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 3. 20 ml Acrylic Cylinder on Endcap 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 4. 20 ml Acrylic Cylinder at 10.17 cm Page 17 of 23 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 5. 400 ml Acrylic Cylinder on Endcap 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 6. 400 ml Acrylic Cylinder at 10.17 cm 0.6 0.8 1.0 1.2 1.410100100010000Meas/True ActivityEnergy (keV)Figure 7. 2.8 l Marinelli Beaker Page 18 of 23 3. Schematic Drawings of ISOXVRFY Geometries

Filter Paper 20 ml Cylinder 400 ml Cylinder Marinelli Beaker Filter Paper 20 ml Cylinder 400 ml Cylinder Position 1 Position 2 source spacer centering disc detector source source filter paper assembly filter paper assembly Page 19 of 23 A. ISOXVRFY Source Certificates Page 20 of 23

! Eckert & Z iegler Analytics CERTIFICATE OF CALIBRA TION Standard Reference Source SRS Number: 106860 Source Descrfption:

2 lnch D i ameter Glass Fiber Filter i n Tape Product Code: MIX-8600-GF-FP Customer:

M i r io n Techno logles (Canberra), Ine. P.O. Number: 4104707, ltem 4 1380 S e aboard lnd ustrla l Blvd. Atlanta, Georgia 303 1 8 Te l 404* 352*8677 F ax 404* 3S2* 2837 www.e2a9.c om t7 ~2cr This standard radionuclide source was prepared from an aliquot measured gravimelrically from a mas te r rad io nucl ide solution calibrated with a germanium gamrna-ray spectrometer system. Additional radionuclides were added gravimetr i cally from solut i ons calibrated by gamma-ray spectromet

.ry , ioniza tio n chamber , or liquid scintillation counting.

Calibr ation and purity were checked using germanium gamrna-ray spectrometry.

At th e time oi calibration no interfer ing gamma-ray emitting impur it ies were detected.

The gamma-ray emission rates for the most intense gamrna-ray line s are given. Eckert & Ziegler Analytics (EZA) ma i n ta ins traceability to t he National Jns tilu te oi Standards and Technology (NlST) through a Measurements Assurance Program as described in USNRC R egulatory Guide 4.15 , Revision 2, July 2007, and compliance with ANSI N42.22-l 995, "Traceab ility oi Radioactive Sources to NIST." Reference Date: 0l-July-2017 GRSMizture 12:00P MEST Half-Llfe , d l.S80E+05 4.614E+02 2.717E+02 l.376E+02 2.770E+Ol l.1S1E+02 6.48SE+Ol l.099E+04 3.121E+02 l.066E+02 2.439E+02 l.92SE+03 Activity, Bg 3.486E+03 2.317E+04 S.342E+02 7.962E+02 2.332E+04 l.378E+03 l.808E+03 6.6llE+02 2.483E+03

2.294E+03 4.9S OE+03 l.090E+03 Oncertamty Gamma-Ray (GRS) master solution is EZA's mix ture tha t consists o f Cd-109, Co-57 , Ce-139, Sn-113, Cs-137, Y-88, and Co-60 {cal ibrat ed quarterly) with the addi ti on o fCr-51 and Sr-85. *Uncertalnty:

U -Rel ative expanded uncertainty, k = 2. See NlST Technical Note 1297, "Guideline s for Evaluating and Exprcooing thc Unccrtainty of N!ST M o asurement Resullo." **Calibration Methoda: 4n LS -4n Liquid Scintillation Counting, HPGe -High Purity Germanium G amrna-Ray Spectrometer, IC -lonization Chamber. (Certifi cat e continued on reverse side) EZA C e rt ificate Program Rev. O. 07-D EC-2015 Page1 of2 Corporat@

Office L.abora tory 2 4 937 Avcnue Tlb bltls Valencla.

California 91355 1380 Seaboard l ndustr la l Blvd. At l anta, Geo r gia, 30318 Page 21 of 23

-Eckert & Zieg ler Ana l ytics 1380 Seaboa r d lndustr i al 8 1 vd. At l a n ta, Georg i a 30318 Te l 404*352*8677 Fax 404*352*2837 www.ezag.com CERT I F I CATE OF CA LI BRATION /1-Z.?S" Standard Reference Source SRS Number: 106858C Source Descrlptlon:

20 ml So l id in Custom Acry li c Cylinder Product Code: M I X-8600-EG-SD Customer:

Mirion Te chno l ogies (Canberra), Ine. P.O. Number: 4104707, ltem 3 This standard radionuc li de source was prepared from an aliquot meas ur ed gravimetrically from a mas te r radionuclide solu t ion calibrated with a germanium gamma-ray spectrometer system. Additional radionuclides were added gravimetrically l'rom solutions calibrated by gamma-ray spectrometry, i onizatio n c h amber, or liquid scintillalion counting.

Calibration and purity were checked using germanium gamma-ray spectrometry.

At the t i me oi calibration no interlering gamma-ray emitting impur ities were detected.

The gamma-ray emission rates lor the most intense gamma-ray lines a r e given. Eckert & Zieg l er Analyt i cs (EZA) main ta ins traceability to t he National lnstitute of Standards and Technology (NIST) through a Measurements Assura.nce Program as described i n USNRC Regulatory Guide 4.1 5, Revision 2, July 2007, and compliance with ANSI N42.22-l 995, "Tr aceability of Radioactive Sources to NIST." Density of solid m atrix: 1.17 g/cm' +/- 3 %. Re!erence Date: 0l-July-2017 12:00PMEST ORSMixture Gamma-Ray Oncertainty Calibratlon lsoto e Ene r , keV Half-Life, d Activi ,B Flux, s.., UA, % U a,°.4 u.% .. M ethod Am-241 69.S l.S80E+OS 7.226E+03 2.S94E+03 0.1 1.8 3.6 4 n LS Cd-109 88.0 4.614E+02 4.802E+04 l.777E+03 o.s 2.0 4.1 HPGe Co-57 122.l 2.717E+02 l.107E+03 9.479E+02 0.4 1.7 3.4 HPGe Ce-139 165.9 l.376E+02 l.6SOE+03 l.320E+03 0.4 1.7 3.6 HPGe Cr-51 320.l 2.770E+Ol 4.833E+04 4.790E+03 0.1 1.7 3.5 IC Sn-113 391.7 l.1S1E+02 2.857E+03 l.856E+03 0.4 1.9 3.9 HPGe Sr-86 614.0 6.485E+Ol 3.747E+03 3.691E+03 0.1 1.7 3.5 IC Cs-137 661.7 l.099E+04 l.370E+03 l.166E+03 0.7 1.9 4.1 HPGe Mn-54 834.8 3.121E+02 6.146E+03 5.14SE+03 0.1 1.7 3.3 IC Y-88 898.0 l.066E+02 4.75SE+03 4.456E+03 0.7 1.7 3.7 HPGe Y-88 1836.l 4.717E+03 0.7 1.7 3.7 Zn-65 1115.5 2.439E+02 l.026E+04 6.134E+03 0.1 1.7 3.5 IC Co-60 1173.2 l.925E+03 2.260E+03 2.257E+03 0.7 1.8 3.9 HPGe Co-60 1332.5 2.260E+03 0.7 1.8 3.9 Gamma-Ray (GRS) master solution is EZA's mix t ure that consis t s of Cd-109, Co-57 , Ce-139, Sn-1 13, Cs-137, Y-88, and Co-60 (oo.Jibratcd quartcrly) with tho addi t ion of Cr-51 and Sr-85. *Uncenalnty

U -Rel ative expanded uncertain ty , k = 2. See NIST Technical Note 1297, " Cuide lin es for Evaluating and Expressing the Uncertainty of NIST Measurement Results." **Callbralion Methoda: 4n LS

• 4n Liquid Scintillation

]: Count i ng, HPCe

• High Purity Cermanium Gamma-Ray Spectromeler, IC -lonization Chamber. # (Cert i ficate continued on r evorse side) ,. EZA Certificate Program Rev. 0, 07-DEC-2015 Pag e 1 of2 Corporate Office Laboratory 24937 Avenue Tl bb itts Va l enci*, Callforn l a 91355 t 380 Seaboard lndustrial Blvd. Atlan t a. Georg i a, 30318 Page 22 of 23 i .,, p 0 -Eckert & Zieg ler Analytics 1380 Seaboard ln dustrial Blvd. At l anta, Georgla 30318 Tel 404* 352* 8677 Fax 404*352*2837 www.ezag.com CERTIFICATE OF CALIBRA T ION Standard Reference Source SRS Number: 1 06856A Source Descrlptlon

400 ml Solid in 16 Ounce MRP PP Plastic Jar Product Code: MIX-8600-EG-SD Customer:

Mirion Technologies (Canberra), Ine. P.O. Number. 4104707, ltem 2 This standard radionuclide source was prepared from an aliquot measured gl'avimetrically from a mas t er radionuclide solulion calibrated with a germanium gamma-ray spectrometer system. Additional radionuclides were added gravimetrically from solulions calibrated by gamma-ray spec t rometry, ioni2a tio n chamber , or liquid scintillation counting.

Calibration and purity were checked us ing germanium gamma-ray spectrometry.

At the time of calibration no in terfering gamma-ray emitting impu rities were detected.

The ga.mma-ray e miss ion rates for the mest intense gamma-ray lines are g i ven. Eckert & Ziegler Analytics (EZA) m aintain s traceability t o t he National lnsti tute of Standards and Tec hnology (NI S T) through a Measurements Assurance Program as described in USNRC Regulatory Cuidc 4.15, Revision 2 , July 2007, and compliance with ANSI N4Z.ZZ-l99S, "Traceability of Radioactive Sources to NIST." Density of solid ma t rix: 1.17 g/cm' +/- 3 %. Reference Date: O 1-July-ZO 17 GRSMixture IZ:OO PMEST 2.439E+02 l.925E+03 Actlvlty, Bq l.404E+04 9.330E+04 2.152E+03 3.207E+03 9.391E+04 5.5SOE+03 7.281E+03 2.663E+03 9.999E+03 9.239E+03 l.994E+04 4.392E+03 Flux, s*1 5.040E+_03 3.452E+03 l.842E+03 2.565E+03 9.306E+03 3.606E+03 7.172E+03 2.266E+03 9.997E+03 8.657E+03 9.165E+03

9.976E+03 4.38SE+03 4.391E+03 Uncertainty 1'A, °lo lln, °/o U,%* 0.1 1.8 3.6 0.5 2.0 4.1 0.4 1.7 3.4 0.4 1.7 3.6 0.1 1.7 3.5 0.4 1.9 3.9 0.1 1.7 3.5 0.7 1.9 4.1 0.1 1.7 3.3 0.7 1.7 3.7 0.7 1.7 3.7 0.1 1.7 3.5 0.7 1.8 3.9 0.7 1.8 3.9 Camma-Ray (CRS) master solution is EZA's mixture that consists oi Cd-109, Co-57 , Ce-139 , Sn-113, Cs-137, Y-88, ;md C o-60 (cal ibrated quarterly) with the addition of Cr-61 and Sr-85. *Uncertainty:

U -R elati ve expa n ded uncertainty, k = Z. See NIST Technical Note 1297 , "Cuidelines for Evaluating and Expressing the Uncertainty oi NIST Measure ment Results." **Calibration Methoda: 4n LS -4n Liquid Scintillation Counting, HPGe -High Purity Cermanium Gamma-Ray Spectromater , IC -l onization Chamber. (Certifieate continued on reversa side) EZA Certificate Program Rev. 0, 07-DEC-2015 Page 1 of2 Corporat*

Offlce L.aboratory 24937 Avenue T l bb l tts Valenda , Ca li fornla 913SS 1 380 Scaboard lndustrlat 8 1 v d. A1f an 1 a, Georg i a, 303 18 Page 23 of 23