Aging and Phase Stability of Waste Package Outer Barrier REV 02, ICN 00
 
ANL-EBS-MD-000002  

September 2004 



1. PURPOSE 
1.1 SUMMARY OF MODEL 
This report was prepared in accordance with Technical Work Plan for: Regulatory Integration 
Modeling and Analysis of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]). 
This report provides information on the phase stability of Alloy 221, the current waste package 
outer barrier material. The goal of this model is to determine whether the single-phase solid 
solution is stable under repository conditions and, if not, how fast other phases may precipitate. 
The aging and phase stability model, which is based on fundamental thermodynamic and kinetic 
concepts and principles, will be used to provide predictive insight into the long-term 
metallurgical stability of Alloy 22 under relevant repository conditions. The results of this 
model are used by General Corrosion and Localized Corrosion of Waste Package Outer Barrier 
as reference-only information. 
These phase stability studies are currently divided into three general areas: 
 Tetrahedrally close-packed (TCP) phase and carbide precipitation in the base metal 
 TCP and carbide precipitation in welded samples 
 Long-range ordering reactions. 
TCP-phase and carbide precipitates that form in Alloy 22 are generally rich in chromium (Cr) 
and/or molybdenum (Mo) (Raghavan et al. 1984 [DIRS 154707]). Because these elements are 
responsible for the high corrosion resistance of Alloy 22, precipitation of TCP phases and 
carbides, especially at grain boundaries, can lead to an increased susceptibility to localized 
corrosion in the alloy. These phases are brittle and also tend to embrittle the alloy 
(Summers et al. 1999 [DIRS 146915]). They are known to form in Alloy 22 at temperatures 
greater than approximately 600C. Whether these phases also form at the lower temperatures 
expected in the repository during the 10,000-year regulatory period must be determined. The 
kinetics of this precipitation will be determined for both the base metal and the weld heataffected 
zone (HAZ). 
The TCP phases (P, , and s) are present in the weld metal in the as-welded condition. It may be 
possible to eliminate these phases through a solution anneal heat treatment, but that may not be 
possible for the closure weld because the spent nuclear fuel cladding cannot be heated to more 
than 350C. The effects of any stress mitigation techniques (such as laser peening or solution 
heat treating) that may be used to reduce the tensile stresses on the closure welds must also be 
determined. Cold-work will cause an increase in dislocation density, and such an increase in 
dislocation density may cause an increase in diffusion rates that control precipitation kinetics 
(Porter et al. 1992 [DIRS 161265]; Tawancy et al. 1983 [DIRS 104991]). 
1 The designation Alloy 22 is used in this report to indicate the alloy composition given by the Society of 
Automotive Engineers (SAE)  American Society of Testing and Materials (ASTM) Unified Numbering System 
(UNS) N06022. A number of manufacturers produce material within this UNS specification. This alloy is sold 
and often referred to in the technical literature by names such as Hastelloy Alloy C22, Inconel Alloy 622, 
Allegheny Alloy AL22, and possibly others. The designation Alloy 22 is, therefore, a generalized designation 
that covers all of these alloys. 

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ANL-EBS-MD-000002 REV 02 1-2 September 2004 
Long-range order (LRO) occurs in nickel (Ni)CrMo alloys (such as Alloy 22) at temperatures 
less than approximately 600C. This ordering has been linked to an increased susceptibility of 
NiCrMo alloys to stress corrosion cracking and hydrogen embrittlement (Tawancy et al. 1983 
[DIRS 104991]). These analyses provide information on the rate at which LRO may occur in 
Alloy 22 under repository conditions. 
Determination of the kinetics of transformations through experimental techniques requires that 
the transformations being investigated be accelerated due to the fact that the expected service life 
is at least 10,000 years. Phase transformations are typically accelerated through an increase in 
temperature. The rate of transformation is determined at the higher temperature and is 
extrapolated to the lower temperatures of interest. 
1.2 INTENDED USE OF MODEL 
In the mill-annealed condition, Alloy 22 (UNS N06022) is primarily a single-phase, facecentered 
cubic (fcc), solid solution with excellent corrosion resistance over a wide range of 
environmental conditions. Over time, other phases (e.g., TCP/carbide and LRO) may precipitate 
and degrade both the mechanical properties and corrosion resistance of the alloy. The goal of 
this model is to determine whether the single-phase solid solution is stable under expected 
repository conditions, and if not, how fast other phases may precipitate. Precipitation kinetics in 
the annealed base metal, as well as in the annealed and laser-peened welds, are considered. 
The objective of this aging and phase stability model is to provide a quantitative model that can 
be used to predict the amount of any phases forming as a function of both time and temperature. 
Due to the long time periods of interest (at least 10,000 years beyond permanent closure), it is 
not practical to obtain or generate data on the metallurgical stability of Alloy 22 using test 
durations of this magnitude. As a result, the aging and phase stability model, which is based on 
fundamental thermodynamic and kinetic concepts and principles, is used to provide predictive 
insight into the long-term metallurgical stability of Alloy 22 under relevant repository 
conditions. Thus, there are no direct inputs from the aging and phase stability model to the Total 
System Performance Assessment for the License Application (TSPA-LA). 
This report also provides justification for excluding FEP 2.1.11.06.0A, Thermal sensitivity of 
waste package. Specifically, deleterious effects due to thermal aging and phase instability of the 
waste package outer barrier will not occur under repository temperature conditions in the 
first 10,000 years and this model report is, thus, a reference source for FEPs Screening of the 
Processes and Issues in the Waste Package and Drip Shield. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 2-1 September 2004 
2. QUALITY ASSURANCE 
This report has been developed in accordance with AP-SIII.10Q, Models, under Technical Work 
Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package 
(BSC 2004 [DIRS 171583]), which, in turn, was developed in accordance with AP-2.27Q, 
Planning for Science Activities. The applicability of requirements frin Quality Assurance 
Requirements and Description (DOE 2004 [DIRS 171539]) is documented in Section 8 of 
Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and 
Waste Package (BSC 2004 [DIRS 171583]). All waste package configurations have been 
determined to be important to waste isolation in accordance with AP-2.22Q and, therefore, are 
classified as Safety Category (SC) in Q-List (BSC 2004 [DIRS 168361], Appendix A; BSC 2004 
[DIRS 170992]). A process control evaluation was performed in accordance with AP-SV.1Q, 
Control of the Electronic Management of Information. Inputs and transfers of data were checked 
to assure completeness and accuracy in accordance with Supplement V requirements. Data were 
also protected from damage and password protected. 

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3. USE OF SOFTWARE 
3.1 BASELINED SOFTWARE 
Thermo-Calc Version M (Thermo-Calc Version M, STN: 10170-M-00 [DIRS 163153]) is a 
commercially available software code that fulfills the need to provide critical modeling and 
analysis of data to: 
 Produce, refine, and analyze multicomponent phase diagrams of alloys at repositoryrelevant 
temperatures for predicting phase stability properties 
 Determine the solidification path and the effect of welding on stability and long-term 
aging of alloys selected for the barriers of the canisters used for storage of nuclear waste 
 Generate isothermal sections of multicomponent alloy phase diagrams at repositoryrelevant 
temperature, isopleths, property diagrams (phase fractions as functions of 
temperature), and composition versus temperature diagrams for all stable and metastable 
phases formed 
 Simulate phase transformations according to the ScheilGulliver model that use local 
equilibria, infinite diffusion in the liquid phase, and no back diffusion in the solid phase 
(Saunders and Miodownik 1998 [DIRS 104975]). 
Thermo-Calc version M is specially designed for systems with strongly nonideal phases and has 
gained a worldwide reputation as the best software application for the calculation of 
multicomponent phase diagrams. Thermo-Calc is the only software commercially available that 
can calculate arbitrary phase diagram sections with up to five independent variables in 
multicomponent systems. There are also modules to calculate many other types of properties, 
such as ScheilGulliver solidification simulations, Pourbaix diagrams, and partial pressures in 
gases. 
Data generated with the Thermo-Calc software also provide the basis for more accurate 
predictions of diffusion kinetics and ultimately time-temperature transformation (TTT) diagrams 
with the DICTRA software (see below) by using diffusion both in the liquid and solid phases. 
The results of the equilibrium solidification and ScheilGullivers simulations generated by 
Thermo-Calc correspond to the upper and lower bounds for the DICTRA results. 
Thermo-Calc generates output in graphical or tabular form. Calculated values are generated by 
Thermo-Calc in a proprietary binary format; however, these files, when processed through 
various modules, produce tabulated data as ASCII text files and graphical data as encapsulated 
Postscript files. 
DICTRA Version 20 (DICTRA V20, STN: 10391-20-00 [DIRS 163154]) is also commercially 
available software that is used in conjunction with Thermo-Calc to calculate the rate at which the 
relevant phase transformations occur. DICTRA Version 20 is used to predict the kinetics of 
phase transformation and evolution in candidate alloys for use in nuclear waste packages. In 
particular, this software application predicts TTT diagrams and, therefore, the aging behavior of 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 3-2 September 2004 
complex FrankKasper phases (or TCP structures), such as the P and s phases, and of the 
ordered phase of the Ni2Cr-type in Alloy 22 and other related alloys. 
DICTRA version 20 fulfills the need to provide critical modeling and analysis of data to: 
 Solve the diffusion equations 
 Calculate thermodynamic equilibrium 
 Solve the flux-balance equations 
 Track the displacement of the phase-interface positions and adjust grid points during 
simulation as a function of time 
 Analyze the kinetics of phase evolution in alloys selected for the barriers of the waste 
package by predicting TTT diagrams for the relevant phases forming as functions of 
time. 
DICTRA interfaces with Thermo-Calc, which handles all thermodynamic calculations needed by 
DICTRA. 
Data files used by Thermo-Calc and DICTRA are included with the purchase of the software and 
are considered to be from documented and substantiated established databases: KP (Kaufman 
binary alloys database), SSOL (Scientific Group Thermodata Europe, or SGTE, solution 
database), MOB (Mobility database), from published journals, and/or from qualified sources. 
The databases are included on the CD-R with the applications. Disaster recovery copies of these 
media are located in the project's Software Configuration Management system, and the original 
media are controlled by the user due to the vendor's licensing and copyright restrictions. The use 
of the data files per AP-SIII.10Q (Section 5.2.1k) are considered qualified for use within this 
report due to 1) reliability of the data source (databases have been reviewed and maintained for 
decades by world-renown experts affiliated with Thermo-calc and DICTRA applying these 
databases to a wide range of industrial applications) and 2) qualifications of personnel or 
organizations generating the data (the databases described above have been generated for 
decades by world-renown experts affiliated with Thermo-calc and DICTRA). Data files that are 
refined by comparing the output data of Thermo-Calc and DICTRA to known experimental data 
that are used to simulate Ni-Cr-Mo-W alloys in this study are described in Section 7. 
The SSOL, KP, and MOB databases are provided in ASCII-text format and can be reviewed or 
edited with any standard text editor. Custom-generated input data can be created using any 
standard text editor to create an ASCII text file. 
DICTRA uses the post-processor module from Thermo-Calc to generate output in graphical or 
tabular form. Calculated values are generated by DICTRA in a proprietary binary format; 
however, these files, when processed through various modules, can produce tabulated data as 
ASCII-text files and graphical data as encapsulated postscript files. 
Thermo-Calc and DICTRA, which run on a Unix or Linux platform, are products of Thermo- 
Calc AB. They were run on a Sun E450/Solaris 2.7. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 3-3 September 2004 
The use of the baselined software described in this section was consistent with its intended use 
and within the documented validation range of the software. 
3.2 EXEMPT SOFTWARE 
Microsoft Excel was used for graphing data, adding trend lines to the data, and manipulating data 
through the use of standard functions included in Excel. Excel is exempt from qualification in 
accordance with LP-SI.11Q-BSC, Sections 2.1.1, 2.1.2, and 2.1.6. When Excel is used for 
calculations and plots (Sections 6.6.5, 6.6.6, and 7.5), information required for an independent 
person to reproduce the work (including formula or algorithm used, listing of inputs, and listing 
of outputs) is provided. 
Image-Pro Plus (Media Cybernetics) is a personal computer software package that is used for the 
analysis of digital images acquired from a transmission electron microscope (TEM), a scanning 
electron microscope (SEM), or an optical microscope. It is used as a quantitative metallographyanalysis 
tool and image processor/analyzer. Although there are many uses for Image-Pro Plus, 
the standard Measure menu commands are used primarily to perform analyses to acquire 
percent-area information. For the analyses presented in this report, these standard Measure 
commands were used to determine the extent of phase precipitation by measuring the appropriate 
image parameters (e.g., white areas) in a large number of SEM images. Details and results of 
these measurements are documented in the scientific notebooks associated with Data Tracking 
Numbers (DTNs) for phase precipitation measurements (Section 4.1.8). Image Pro-Plus 
software versions 4.0, 4.1, and 4.5.1 have been determined to be exempt from qualification in 
accordance with LP-SI.11Q-BSC, Sections 2.1.2 and 2.1.6. 
KaleidaGraph version 3.5 (Synergy Software), ClarisDraw version 1.04, and Adobe Illustrator 
Version 8 were used for graphing data. The graphs are for visual representation of the data only, 
and all points plotted were checked by visual inspection. These software packages are exempt 
from qualification per LP-SI.11Q-BSC, Section 2.1.2. The actual tables of values plotted are 
presented in this document so that any approved software can be used to plot the data, if 
necessary. 
3.3 SUMMARY OF SOFTWARE USED 
A summary list of the software used in this model report is shown in Table 1. 
Table 1. Summary List of Software Used 
Software Name Version Number Software Tracking Number 
Thermo-Calc M 10170-M-00 
DICTRA 20 10391-20-00 
Image-Pro Plus 4.0, 4.1, and 4.5.1 Exempt 
Excel 2000 Exempt 
KaleidaGraph 3.5 Exempt 
ClarisDraw 1.04 Exempt 
Adobe Illustrator 8 Exempt 

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4. INPUTS 
4.1 DIRECT INPUTS 
The input data used in this model report are summarized in Table 2. All micrographs and data 
are the result of waste package materials testing activities. A discussion of the uncertainty for 
these data can be found in Section 6.7. 
Sections 4.1.1 through 4.1.4 present representative examples of micrographs that were used in 
the phase identification and kinetic observations that are described in Sections 6.3.1 and 6.3.3. 
Sections 4.1.5 through 4.1.7 present SEM micrographs that are representative examples of 
micrographs used in the area-fraction measurements presented in Section 4.1.8. 
The input data presented here are appropriate for this study because scanning or tunneling 
electron microscopy are the most direct methods to determine the extent of phase precipitation 
after aging at specified times and temperatures. The micrographs and phase fraction 
measurements presented here are direct input for the direct metallurgical observations and insight 
trends supporting the Alloy 22 computational model as discussed in Section 6. Data used to 
validate the model may be found in Section 7. Data used for model development was not used 
for model validation. 
Table 2. Aging and Phase Stability of Waste Package Outer Barrier Analysis Direct Input Data 
Data Name Data Source DTN Data Use 
Transmission Electron Microscopy 
Micrographs Used in Preliminary TCP and 
Carbide Phase Identification 
Waste Package 
Materials Testing 
LL010107712251.012 
[DIRS 155299] 
Section 4.1.1 
Micrographs Showing Precipitation in Alloy 
22 Beginning on and Covering Grain 
Boundaries, Beginning on Twin Boundaries, 
and Beginning within the Grains 
Waste Package 
Materials Testing 
LL010107712251.012 
[DIRS 155299] 
Section 4.1.2 
Micrographs Showing TCP Particles in Alloy 
22 Welds 
Waste Package 
Materials Testing 
LL030301612251.040 
[DIRS 162691] 
Section 4.1.3 
TEM Micrographs Showing When LRO Has 
Been Observed 
Waste Package 
Materials Testing 
LL010107712251.012 
[DIRS 155299] 
LL030301612251.040 
[DIRS 162691] 
Section 4.1.4 
SEM Micrographs Used for Quantification of 
Phases and LRO 
Waste Package 
Materials Testing 
LL030104212251.012 
[DIRS 162009] 
Section 4.1.5 
SEM Micrographs Showing Bulk Precipitation 
in Base Metal 
Waste Package 
Materials Testing 
LL030103712251.007 
[DIRS 163014] 
Section 4.1.6 
SEM Micrographs Showing Precipitation in 
Weld Metal 
Waste Package 
Materials Testing 
LL030104212251.012 
[DIRS 162009] 
LL021009912251.003 
[DIRS 163013] 
Section 4.1.7 
Grain Boundary Precipitation Measurements 
(Grain Boundary Coverage Fraction) 
Waste Package 
Materials Testing 
LL030104012251.010 
[DIRS 162468] 
Section 4.1.8 
Precipitation Area-Fraction Measurements on 
Weld Metal 
Waste Package 
Materials Testing 
LL030103612251.006 
[DIRS 162012] 
Section 4.1.8 

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4.1.1 Transmission Electron Microscopy Micrographs Used in Preliminary TCP and 
Carbide Phase Identification 
This section contains transmission electron microscopy (TEM) images and electron-selected area 
diffraction (SAD) patterns used to identify the phases that form in Alloy 22 base metal after 
aging in the temperature range of 593C to 760C (Figure 1 through Figure 15). Because of the 
structural similarity of the  and P phases, some diffraction patterns could be indexed as either 
phase. For this reason, the phases forming in some cases are only tentatively identified. Several 
carbides form in Alloy 22, but they all have very similar structures. Although they are 
significantly different chemically, it is not possible to distinguish them in the work reported here. 
They are, therefore, simply called carbide. 
The ambiguities in identifying the exact composition of the TCP phases or carbides have no 
impact on the aging and phase stability model because (1) the TCP phases are structurally 
similar, and (2) the carbides are structurally similar. Therefore, the phase kinetics among TCP 
phases and among carbides will also be similar. The effects of TCP/carbide phases on corrosion 
behavior are treated empirically as TCP phase effects on aging so specific identification of the 
individual TCP phases is not necessary. 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was identified as P phase (TS393-049b, Image S0244, 8/23/99, SN-LLNL-SCI-442, p. 19). 
Figure 1. Grain Boundary Precipitation in Alloy 22 Aged for 1,000 Hours at 593C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: The grain boundary precipitate identified as P appears light (TS393-049b, Image S0245, 8/23/99, 
SN-LLNL-SCI-442, p. 19). 
Figure 2. Dark-Field Image Corresponding to Figure 1 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This pattern was indexed as P phase (TS393-049b, Image S0246, 8/23/99, SN-LLNL-SCI-442, p. 20). 
Figure 3. SAD Pattern from the Grain Boundary Precipitate Shown in Figure 1 and Figure 2 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was identified as P phase (TS369-003a, Image S0125, 3/9/99, SN-LLNL-SCI-434, p. 41). 
Figure 4. Grain Boundary Precipitation (P Phase) in Alloy 22 Aged for 16,000 Hours at 593C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: The grain boundary precipitate identified as P appears light (TS369-003a, Image S0126, 3/9/99, SN-LLNLSCI-
434, p. 42). 
Figure 5. Dark-Field Image Corresponding to Figure 4 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This pattern was indexed as P phase (TS369-003a, Image S0124, 3/9/99, SN-LLNL-SCI-434, p. 43). 
Figure 6. SAD Pattern from the Grain Boundary Precipitate Shown in Figure 4 and Figure 5 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was identified as carbide (TS369-003a, Image 1490, 12/16/98, SN-LLNL-SCI-393, p. 66). 
Figure 7. Grain Boundary Precipitation (carbide) in Alloy 22 Aged for 16,000 Hours at 593C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This pattern was indexed as carbide (TS369-003a, Image 1489, 12/16/98, SN-LLNL-SCI-393, p. 66). 
Figure 8. SAD Pattern from the Grain Boundary Precipitate Labeled Carbide in Figure 7 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was identified as P phase (TS369-004a, Image S0037, 2/16/99, SN-LLNL-SCI-434, p. 63). 
Figure 9. Precipitate (P phase) in Alloy 22 Aged for 16,000 Hours at 760C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: The precipitate identified as P phase appears light (TS369-004a, Image S0038, 2/16/99, 
SN-LLNL-SCI-434, p. 63). 
Figure 10. Dark-Field Image Corresponding to Figure 9 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-004a, Image S0036, 2/16/99, SN-LLNL-SCI-434, p. 64). 
Figure 11. SAD Pattern from the P-Phase Precipitate Shown in Figure 9 and Figure 10 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was tentatively identified as  phase (TS369-004a, Image 1312, 3/14/98, SN-LLNL-SCI-393, 
p. 11). 
Figure 12. Precipitation (Possibly  Phase) in Alloy 22 Aged for 16,000 Hours at 760C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-004a, Image 1314, 3/14/98, SN-LLNL-SCI-393, p. 13). 
Figure 13. SAD Pattern from the -Phase Precipitate Shown in Figure 12 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: This phase was identified as  phase (TS369-004a, Image 1309, 3/14/98, SN-LLNL-SCI-369, p. 135). 
Figure 14. Grain Boundary Precipitation in Alloy 22 Aged for 16,000 Hours at 760C Showing in 
-Phase Precipitation 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-004a, Image 1310, 3/14/98, SN-LLNL-SCI-369, p. 150). 
Figure 15. SAD Pattern from the -Phase Precipitate Shown in Figure 14 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: The larger, brighter phase was identified as s. The smaller precipitates are either  or P phase 
(TS369-004a, Image 1300, 3/14/98, SN-LLNL-SCI-369, p. 66). 
Figure 16. Grain Boundary Precipitation in Alloy 22 Aged for 16,000 Hours at 760C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-004a, Image 1306, tilted (11,9) from image 1300, 3/14/98, SN-LLNL-SCI-369, p. 98). 
Figure 17. SAD Pattern from the s-Phase Precipitate Shown in Figure 16 

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4.1.2 Micrographs Showing Precipitation in Alloy 22 Beginning on and Covering Grain 
Boundaries, Beginning on Twin Boundaries, and Beginning Within the Grains 
This section contains optical and scanning electron microscopy (SEM) images (Figure 18 
through Figure 34) used to determine the times at which the various stages of TCP and carbide 
precipitation occur in Alloy 22 base metal after aging in the temperature range of 593C to 
800C for durations ranging from 1 to 16,000 hours. No distinction has been made between the 
various TCP phases and the carbides that form in Alloy 22. The TCP phases , P, and s are 
virtually indistinguishable in the SEM (as shown in the preceding section, the phases are 
discernable in the TEM), and there is relatively little carbide precipitation. 
Similar to the discussion in Section 4.1.1, the ambiguities in the exact composition of the TCP 
phases or carbides have no impact on the aging and phase stability model due to structural 
similarities among TCP phases and also among carbides. Thus, the phase kinetics among TCP 
phases and also among carbides will also be similar. 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-028a, 2/15/99, SN-LLNL-SCI-434, p. 7). 
Figure 18. SEM Micrograph Showing Precipitation Just Beginning on Grain Boundaries after Aging 
Alloy 22 for 10 Hours at 593C 

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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-029a, 2/15/99, SN-LLNL-SCI-434, p. 8). 
Figure 19. SEM Micrograph Showing Precipitation on Grain Boundaries after Aging Alloy 22 for 
100 Hours at 593C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-008a, 12/7/98, SN#434, p. 10). 
Figure 20. Optical Micrograph Showing No Precipitation on Grain Boundaries after Aging Alloy 22 for 
1 Hour at 649C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-008a, 12/7/98, SN-LLNL-SCI-434, p. 10). 
Figure 21. SEM Micrograph Showing Little or No Precipitation on Grain Boundaries after Aging 
Alloy 22 for 1 Hour at 649C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-009a, 12/7/98, SN-LLNL-SCI-434, p. 11). 
Figure 22. SEM Micrograph Showing Precipitation on Grain Boundaries after Aging Alloy 22 for 
10 Hours at 649C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-010a, 12/7/98, SN-LLNL-SCI-434, p. 12). 
Figure 23. SEM Micrograph Showing Precipitation on Grain Boundaries after Aging Alloy 22 for 
100 Hours at 649C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-011a, 12/7/98, SN-LLNL-SCI-434, p. 12). 
Figure 24. SEM Micrograph Showing Precipitation on Grain Boundaries after Aging Alloy 22 for 
1,000 Hours at 649C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-15 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-011a, 12/7/98, SN-LLNL-SCI-434, p. 13). 
Figure 25. SEM Micrograph Showing Precipitation on Grain and on Twin Boundaries after Aging 
Alloy 22 for 1,000 Hours at 649C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-008b, 8/28/98, SN-LLNL-SCI-434, p. 14). 
Figure 26. SEM Micrograph Showing Precipitation on Grain Boundaries and within the Grains after 
Aging Alloy 22 for 16,000 Hours at 649C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-16 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-014, 11/30/98, SN-LLNL-SCI-434, p. 19). 
Figure 27. Low-Magnification SEM Micrograph Showing that Grain Boundary Precipitation has Begun 
after Aging Alloy 22 for 1 Hour at 760C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-014, 11/30/98, SN-LLNL-SCI-434, p. 20). 
Figure 28. High-Magnification SEM Micrograph Showing that Grain Boundary Precipitation has Begun 
after Aging Alloy 22 for 1 Hour at 760C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-17 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-015, 11/30/98, SN-LLNL-SCI-434, p. 21). 
Figure 29. SEM Micrograph Showing Significant Grain Boundary Precipitation after Aging Alloy 22 for 
10 Hours at 760C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-016, 11/30/98, SN-LLNL-SCI-434, p. 22). 
Figure 30. SEM Micrograph Showing Significant Grain Boundary Precipitation and Precipitation on 
Twin Boundaries after Aging Alloy 22 for 119 Hours at 760C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-18 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-007a, 12/7/98, SN-LLNL-SCI-434, p. 22). 
Figure 31. SEM Micrograph Showing Significant Precipitation Within the Grains of Alloy 22 after Aging 
for 1,000 Hours at 760C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-020a, 2/15/99, SN-LLNL-SCI-434, p. 25). 
Figure 32. SEM Micrograph Showing Grain Boundary Precipitation in Alloy 22 after Aging for 1 Hour 
at 800C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-19 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-021a, 2/15/99, SN-LLNL-SCI-434, p. 26). 
Figure 33. SEM Micrograph Showing Significant Grain Boundary Precipitation in Alloy 22 after Aging 
for 10 Hours at 800C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS393-022a, 2/15/99, SN-LLNL-SCI-434, p. 27). 
Figure 34. SEM Micrograph Showing Precipitation on Grain Boundaries, on Twin Boundaries, and 
within the Grains after Aging Alloy 22 for 100 Hours at 800C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-20 September 2004 
4.1.3 Micrographs Showing TCP Particles in Alloy 22 Welds 
The TCP phases , P, and s are known to form in Alloy 22 welds (Cieslak et al. 1986 
[DIRS 104966], p. 2,041, paragraph 2). This section contains optical, SEM, and TEM images 
(Figure 35 through Figure 44) in the preliminary characterization of Alloy 22 welds. 
Two samples have been examined: one was examined in the as-welded condition; the other was 
aged for 40,000 hours at 427C. Although the two welds were produced in the same way, the 
aged sample did not come from the same weld, as did the unaged sample. Therefore, some 
variation is expected between the samples, and direct comparisons based on the small scale of 
differences seen between these samples should not be made. 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: Only approximately three-quarters of the half-inch plate is shown (TS369-019, 8/28/98, SN-LLNL-SCI-393, 
pp. 9 to 10). 
Figure 35. Low-Magnification (25) Optical Micrograph of an Alloy 22 Multipass, Double-V 
Gas-Tungsten-Arc-Welding (GTAW) Weld with Matching Filler Metal (As-Welded) 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-21 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: (TS369-019, 8/28/98, SN-LLNL-SCI-393, p. 10). 
Figure 36. SEM Micrograph of the Alloy 22 Weld Shown in Figure 35 Showing the Dendritic Structure 
Typical of Welds 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: TCP particles are seen to form in the interdendritic regions (TS369-019 SC11, 8/28/98, SN-LLNL-SCI-393, 
p. 10). 
Figure 37. SEM Micrograph of the Alloy 22 Weld Shown in Figure 35 Showing the Dendritic Structure 
Typical of Welds (Near Top of Plate; Center of Weld; Higher Magnification) 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-22 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: Only approximately one-half of the half-inch plate is shown (TS369-005b, 5/12/98, SN-LLNL-SCI-369, 
p. 20). 
Figure 38. Low-Magnification Optical Micrograph of an Alloy 22 Weld and Aged for 40,000 Hours at 
427C 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The white TCP particles are distributed non-uniformly throughout the weld (TS369-005b, 5/12/98, 
SN-LLNL-SCI-369, p. 20). 
Figure 39. SEM Micrograph of the Alloy 22 Weld Shown in Figure 38 at the Junction of Two Weld 
Passes 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-23 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: TCP particles are seen to form in the interdendritic regions, as was seen in the unaged weld of Figure 37 
(TS369-005b, 5/12/98, SN-LLNL-SCI-369, p. 20). 
Figure 40. SEM Micrograph of the Alloy 22 Weld Shown in Figure 38 Showing the Dendritic Structure 
Typical of Welds 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: Very few precipitates are noticeable (white specks) in the Heat-Affected Zone (HAZ) of the aged weld 
(TS369-005b, 5/12/98, SN-LLNL-SCI-369, p. 20). 
Figure 41. Optical Micrograph at the Fusion Line of the Alloy 22 Weld Shown in Figure 42 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-24 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: This particle was not conclusively identified, but could be either P or s (TS369-005a, Image 1373, 5/21/98, 
SN-LLNL-SCI-393, p. 27). 
Figure 42. One of Few Precipitates Seen using TEM in the Alloy 22 Weld of Figure 38 Aged for 
40,000 Hours at 427C 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: This pattern could be indexed as either P phase or s (TS369-005a, Image 1375, 5/21/98, SN-LLNL-SCI- 
393, p. 31). 
Figure 43. SAD Pattern from the Precipitate Shown in Figure 42 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-25 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: A SAD pattern was not taken from this particle, but it appears to be a carbide and was probably present in 
the base metal prior to welding (TS369-005a, Image 1378, 5/22/98, SN-LLNL-SCI-393, p. 37). 
Figure 44. TEM Micrograph Showing a Precipitate, Possibly Carbide, in the HAZ of the Aged Alloy 22 
Weld of Figure 38 
4.1.4 TEM Micrographs Showing When LRO Has Been Observed 
This section contains a representative sampling of the TEM micrographs (Figure 45 through 
Figure 56) showing instances when LRO has been observed in aged Alloy 22 samples. In these 
sample micrographs, LRO has been observed in Alloy 22 base metal after aging for 16,000 hours 
at 593C and in Alloy 22 welds after aging for 40,000 hours at 427C. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-26 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: (TS369-003a, Image 1484, 12/16/98, SN-LLNL-SCI-393, p. 61). 
Figure 45. TEM Micrograph Showing LRO Domains in an Alloy 22 Base Metal Sample Aged for 
16,000 Hours at 593C 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: One or more variants of the ordered domains appears light (TS369-003a, Image 1485, 12/16/98, 
SN-LLNL-SCI-393, p. 61). 
Figure 46. Dark-Field Image Corresponding to Figure 45 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-27 September 2004 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
NOTE: The faint superlattice reflections are due to LRO (TS369-003a, Image 1483, 12/16/98, SN-LLNL-SCI-393, 
pp. 61 to 65). 
Figure 47. SAD Pattern from the Area Shown in Figure 45 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: (TS369-005a base metal, Image 1354, 3/20/98, SN-LLNL-SCI-369, p. 132) Bright field image from 
base-metal region of sample TS369-005a. 
Figure 48. TEM Micrograph from the Base Metal of an Alloy 22 Weld Sample Aged for 40,000 Hours 
at 427C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-28 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: One or more variants of the ordered domains appears light (TS369-005a base metal, Image 1356, 
3/20/98, SN-LLNL-SCI-369, p. 133). White spots are ordered precipitates. 
Figure 49. Dark-Field Image from 1/3 <220> Reflection 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The faint superlattice reflections are due to LRO (TS369-005a base metal, Image 1353, 3/20/98, 
SN-LLNL-SCI-369, p. 131). The faint spots occur at 1/3 and 2/3 <220>. 
Figure 50. SAD Pattern from the Area Shown in Figure 48, Typical fcc <110> Zone Axis 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-29 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: (TS369-005a weld metal, Image 1371, 5/21/98, SN-LLNL-SCI-393, p. 26). 
Figure 51. TEM Micrograph from the Weld Metal of an Alloy 22 Multipass, Double-V GTAW Weld with 
Matching Filler Metal Aged for 40,000 Hours at 427C 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The faint white regions are ordered domains (TS369-005a weld metal, Image 1372, 5/21/98, 
SN-LLNL-SCI-393, p. 26). White spots are Ni2(Cr,Mo) precipitates. 
Figure 52. Dark-Field Image Corresponding to Figure 51 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-30 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The faint superlattice reflections indicate that ordering has occurred (TS369-005a weld metal, Image 1370, 
5/21/98, SN-LLNL-SCI-393, p. 25). 
Figure 53. SAD Pattern from the Area Shown in Figure 51 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: (TS369-005a HAZ, Image 1379, 5/22/98, SN-LLNL-SCI-393, p. 38). 
Figure 54. TEM Micrograph from the HAZ of the Alloy 22 Multipass, Double-V GTAW Weld with 
Matching Filler Metal Aged for 40,000 Hours at 427C 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-31 September 2004 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The faint white regions are ordered domains (TS369-005a HAZ, Image 1380, 5/22/98, SN-LLNL-SCI-393, 
p. 39). 
Figure 55. Dark-Field Image Corresponding to Figure 54, Taken from One of the 1/3 <220> 
Reflections Shown in Figure 56 
Source: DTN: LL030301612251.040 [DIRS 162691]. 
NOTE: The faint superlattice reflections are due to LRO (TS369-005a HAZ, Image 1381, 5/22/98, 
SN-LLNL-SCI-393, p. 39). 
Figure 56. SAD Pattern from the Area Shown in Figure 54, Showing 1/3 <220> Superlattice Reflections 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-32 September 2004 
4.1.5 SEM Micrographs Used for Quantification of Phases and LRO 
This section shows an example of a SEM micrograph used to quantify phases present at the onset 
of LRO. Figure 57 shows evidence of the onset of LRO (right-hand side of image) in base metal 
aged at 550C for 21,052 hours. In addition, the Mo-rich  and P phases are evident at the 
boundary (white areas). 
Source: DTN: LL030104212251.012 [DIRS 162009]. 
NOTE: Mo-rich  and P phases are also evident at interface (Sample No. TS444-012B2B). 
Figure 57. Base Metal Aged at 550C for 21,052 Hours and Exhibits Ordered Matrix in 
Right-Hand Region 
4.1.6 SEM Micrographs Showing Bulk Precipitation in Base Metal 
The micrographs in this section (Figure 58 through Figure 65) are representative of SEM 
micrographs that are used as input to determine area-fraction coverage in the bulk matrix of base 
metal as a function of time and temperature. The software package, Image-Pro Plus, analyzes 
the micrographs to determine area-fraction coverage. The volume fraction of precipitates (as 
function of time and temperature) is equivalent to the area-fraction measurement (Section 6.6.3) 
(Vander Voort 2000 [DIRS 161300], Hilliard and Cahn 1961 [DIRS 161454]). The area-fraction 
measurements on base metal are presented in Table 9. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-33 September 2004 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Precipitates in the bulk matrix are noticeable (Sample No. TS369-008b). 
Figure 58. Base Metal aged at 649C for 16,000 Hours 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Due to higher temperature, precipitation in the bulk matrix is more pronounced than shown in Figure 58 
(Sample No. TS369-009b). 
Figure 59. Base Metal Aged at 704C for 16,000 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-34 September 2004 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Few precipitates in the bulk matrix are evident at this temperature after short time 
(Sample No. TS369 016a). 
Figure 60. Base Metal Aged at 760C for 119 Hours 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: More precipitation is evident after a longer aging time than was used as shown in Figure 60 
(Sample No. TS393-007a). 
Figure 61. Base Metal Aged at 760C for 1,000 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-35 September 2004 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Significant precipitation is evident in the bulk matrix at the longer aging time, as compared to that shown in 
Figure 61 (Sample No. TS369-018a). 
Figure 62. Base Metal Aged at 760C for 2,000 Hours 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Precipitation is extensive in the bulk matrix at this temperature and long aging time 
(Sample No. TS369-004b). 
Figure 63. Base Metal Aged at 760C for 16,000 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-36 September 2004 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Precipitation in the bulk matrix is minimal at this high temperature, but short aging time 
(Sample No. TS393-022a). 
Figure 64. Base Metal Aged at 800C for 100 Hours 
Source: DTN: LL030103712251.007 [DIRS 163014]. 
NOTE: Precipitation in the bulk matrix is more extensive at this temperature due to the longer aging time, as 
compared to that shown in Figure 64 (Sample No. TS393-023a). 
Figure 65. Base Metal Aged at 800C for 1,002 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-37 September 2004 
4.1.7 SEM Micrographs Showing Precipitation in Weld Metal 
Similar to the procedure described for base metal (Section 4.1.6), the micrographs in this section 
(Figure 66 through Figure 73) are representative of SEM micrographs that are used as input to 
determine area-fraction coverage in the weld metal as a function of time and temperature. 
Again, the software package Image-Pro Plus analyzes the micrographs to determine area 
coverage. The volume fraction of precipitates (as function of time and temperature) is equivalent 
to the area-fraction measurement (Section 6.6.3) (Vander Voort 2000 [DIRS 161300], Hilliard 
and Cahn 1961 [DIRS 161454]). The area-fraction measurements on weld metal are presented in 
Table 4. 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: (Sample No. TS441-033b3). 
Figure 66. Weld Metal, As-Welded Condition 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-38 September 2004 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: A minimal amount of precipitates are noticeable along the interdendritic regions (Sample No. 
TS441-056b). 
Figure 67. Weld Metal Aged at 593C for 30 Hours 
Source: DTN: LL030104212251.012 [DIRS 162009]. 
NOTE: Using a lower magnification, a minimal amount of precipitation can be seen to align with the interdendritic 
regions (Sample No. TS441-061b). 
Figure 68. Weld Metal Aged at 593C for 1,000 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-39 September 2004 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: Due to higher temperature, precipitates are evident in the weld metal (Sample No. TS441-041b3). 
Figure 69. Weld Metal Aged at 704C for 10 Hours 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: Due to longer aging time, precipitation along the interdendritic regions is more evident 
(Sample No. TS441-062b3). 
Figure 70. Weld Metal Aged at 704C for 100 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-40 September 2004 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: Close-up micrograph of precipitates evident in weld metal at this higher temperature 
(Sample No. TS441-035b). 
Figure 71. Weld Metal Aged at 760C for 3 Hours 
Source: DTN: LL030104212251.012 [DIRS 162009]. 
NOTE: High magnification image of precipitates formed at higher temperature in weld metal 
(Sample No. TS441-036b). 
Figure 72. Weld Metal Aged at 760C for 6 Hours 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-41 September 2004 
Source: DTN: LL021009912251.003 [DIRS 163013]. 
NOTE: At this temperature and longer aging time, the precipitates are shown to be more extensive and align along 
the interdendritic regions in the weld metal (Sample No. TS441-047b). 
Figure 73. Weld Metal Aged at 760C for 60 Hours 
4.1.8 Volume-Fraction Measurements 
Volume fraction measurements are used to determine the extent of phase precipitation as 
function of time and temperature. As a result, the volume fraction measurements are used as 
inputs to the aging and phase stability model to estimate phase precipitation along grain 
boundaries and in weld metal. The volume fraction data used in the aging and phase stability 
model for grain boundary coverage and weld metal are shown in Table 3 and Table 4. Details of 
the volume-fraction measurements can be found in the scientific notebooks associated with 
DTNs: LL030104012251.010 [DIRS 162468] and LL030103612251.006 [DIRS 162012]. 
As mentioned previously, the micrographs shown in Sections 4.1.5 through 4.1.7 are a 
representative sampling of the multitude of micrographs used for volume fraction measurements. 
As a result, there is not a direct correspondence between the representative micrographs and 
values shown in Table 3 and Table 4. 
The standard deviations and 95% confidence intervals are calculated per ASTM E 562-95 
[DIRS 161301], Standard Test Method for Determining Volume Fraction by Systematic Manual 
Point Count. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-42 September 2004 
Table 3. Grain Boundary Precipitation Measurements (Grain Boundary Coverage Fraction) 
Temperature 
(C) 
Time 
(hr) 
Grain Boundary 
Coverage Fraction 
Standard 
Deviation 
95% Confidence 
Interval 
427 40,000 0 0 0 
649 6 0 0 0 
649 600 0.84 0.05 0.04 
704 10 0.5 0.13 0.07 
704 60 0.92 0.06 0.03 
760 0.5 0.51 0.16 0.085 
760 3 0.79 0.06 0.03 
Source: DTN: LL030104012251.010 [DIRS 162468] 
Table 4. Precipitation Area-Fraction Measurements on Weld Metal 
Temperature 
(C) 
Time 
(hr) 
Area Fraction 
(%) 
Standard 
Deviation 
95% Confidence 
Interval 
As-Welded 0 0.16 0.15 0.047 
593 30 0.24 0.27 0.091 
593 60 0.29 0.24 0.074 
593 100 0.21 0.21 0.060 
593 300 0.36 0.28 0.091 
593 600 0.28 0.21 0.063 
593 1,000 0.24 0.21 0.071 
649 10 0.24 0.24 0.077 
649 30 0.27 0.24 0.085 
649 60 0.17 0.23 0.092 
649 100 0.34 0.24 0.085 
649 300 1.27 0.92 0.268 
649 600 1.99 1.46 0.494 
704 3 0.21 0.27 0.081 
704 6 0.29 0.34 0.096 
704 10 0.26 0.18 0.073 
704 30 0.73 0.76 0.222 
704 60 1.01 0.76 0.243 
704 100 2.64 2.03 0.718 
760 1 0.21 0.22 0.072 
760 3 0.69 0.63 0.190 
760 6 0.97 1.09 0.286 
760 10 1.10 0.87 0.341 
760 30 3.24 1.53 0.559 
760 60 4.17 1.3 0.467 
760 100 7.77 1.92 0.659 
Source: DTN: LL030103612251.006 [DIRS 162012] 
NOTE: Confidence interval values rounded to three decimal places 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-43 September 2004 
As expected, there is more uncertainty in the volume fraction measurements on specimens 
subjected to lower temperatures and/or shorter aging times. At lower temperatures or shorter 
aging times, the amount of TCP-phase precipitated can be very small, and as a result, the volume 
fraction measurements have been performed on minimally detectable levels of precipitates (near 
zero). Thus, it is not surprising that for lower temperatures or shorter aging times, the standard 
deviations would be large. As expected, the uncertainty is considerably reduced in 
measurements where significant amounts (> 5%) of precipitation have occurred. A more 
detailed discussion of uncertainty is given in Section 6.7. 
4.2 CRITERIA 
Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and 
Waste Package (BSC 2004 [DIRS 171583]) has identified the following acceptance criteria (AC) 
based on the requirements mentioned in Project Requirements Document (Curry et al. 2002 
[DIRS 157916]) and Yucca Mountain Review Plan, Final Report (NRC 2003 [DIRS 163274]): 
 Degradation of Engineered Barriers (NRC 2003 [DIRS 163274], Section 4.2.1.3.1.3; 
PRD-002/T-015). 
Specific requirements include describing deterioration or degradation of engineered barriers and 
modeling degradation processes using data for performance assessment, including TSPA-LA. 
Consideration of uncertainties and variabilities in model parameters and alternative conceptual 
models are also required. To fulfill these requirements, the following acceptance criteria are 
identified in Technical Work Plan for: Regulatory Integration Modeling and Analysis of the 
Waste Form and Waste Package (BSC 2004 [DIRS 171583]): 
Description and Demonstration of Multiple Barriers Acceptance Criteria 
The following acceptance criteria are from Section 2.2.1.1.3 of Yucca Mountain Review Plan, 
Final Report (NRC 2003 [DIRS 163274]): 
 Acceptance Criterion 1  Identification of Barriers is Adequate 
 Acceptance Criterion 2  Description of Barrier Capability to Isolate Waste is 
Acceptable 
 Acceptance Criterion 3  Technical Basis for Barrier Capability is Adequately 
Presented. 
Degradation of Engineered Barriers 
The following acceptance criteria are from Section 2.2.1.3.1.3 of Yucca Mountain Review Plan, 
Final Report (NRC 2003 [DIRS 163274]): 
 Acceptance Criterion 1  System Description and Model Integration are Adequate 
 Acceptance Criterion 2  Data Are Sufficient for Model Justification 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 4-44 September 2004 
 Acceptance Criterion 3  Data Uncertainty is Characterized and Propagated through the 
Model Abstraction 
 Acceptance Criterion 4  Model Uncertainty is Characterized and Propagated Through 
the Model Abstraction 
 Acceptance Criterion 5  Model Abstraction Output is Supported by Objective 
Comparisons. 
4.3 CODES AND STANDARDS 
The codes and standards applicable to this report are: 
 Standard Specification for Low-Carbon Nickel-Molybdenum-Chromium, Low-Carbon 
Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, 
Low-Carbon Nickel-Chromium-Molybdenum-Tantalum, and Low-Carbon Nickel- 
Chromium-Molybdenum-Tungsten Alloy Plate, Sheet, and Strip (ASTM B 575-99a 
[DIRS 147465]) 
 Standard Practice for Prediction of the Long-Term Behavior of Materials, Including 
Waste Forms, Used in Engineered Barrier Systems (EBS) for Geological Disposal of 
High-Level Radioactive Waste (ASTM C 1174-97 [DIRS 105725]) 
 Standard Test Method for Determining Volume Fraction by Systematic Manual Point 
Count (ASTM E 562-95 [DIRS 161301]). 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 5-1 September 2004 
5. ASSUMPTIONS 
5.1 KINETICS THE SAME FOR THE TCP AND CARBIDE PHASES IN ALLOY 22 
The relative amounts of , P, s, and carbide phases have not been quantified; therefore, the 
kinetics of formation of these phases cannot be calculated independently at this time. It is 
reasonable to assume that their rates of formation are similar. This assumption is based on the 
following observations. The amounts of carbide and s phase tend to be low in the samples 
examined thus far. Therefore, the rates of formation of these phases are not likely to contribute 
significantly to the overall performance of the waste package outer barrier, nor are they likely to 
affect the transformation rates calculated based on volume fraction measurements, which include 
these phases in the total precipitate volume. The  and P phases are very similar (Leonard 1969 
[DIRS 104970], p. 225; Raghavan et al. 1982 [DIRS 146956], p. 983, Conclusions, point 2), and 
the rates at which they form are likely to be similar. It also appears that P phase is a precursor to 
 phase (Leonard 1969 [DIRS 104970], p. 223, Figure 1). This would also explain why more 
P phase (relative to the amount of  phase) has been observed at the lower temperatures than at 
the higher temperatures. If P phase is a precursor to  phase, including the total amount of P +  
as input to the kinetic model is appropriate. For the reasons described above, this assumption 
does not require confirmation. This assumption is used in the preliminary kinetic observations 
discussed in Section 6.3.1. 
5.2 TRANSFORMATION MECHANISMS OPERATING AT THE HIGHER 
TEMPERATURES INVESTIGATED ALSO OPERATE AT THE LOWER 
EXPECTED REPOSITORY TEMPERATURES 
For a waste package lifetime expected to be, at a minimum, 10,000 years, it is impossible to test 
directly in the laboratory the behavior of waste package outer barrier materials under expected 
repository conditions. The changes that may occur in these materials must be accelerated. For 
phase-stability studies, phase transformations are accelerated by increasing test temperatures 
above those anticipated in the repository (~200C). Extrapolation to low temperatures of kinetic 
data taken at high temperatures assumes that the mechanism by which phases form at high 
temperatures also operates at lower temperatures. The lower the temperature from which the 
extrapolation is made, the more likely the validity of these assumptions. Theoretical modeling 
aimed at calculating the Alloy 22 phase diagram and precipitation kinetics has been performed 
that further support the use of this assumption. This assumption is used in Sections 6.1.2 and 6.6 
and does not require confirmation. 

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Aging and Phase Stability of Waste Package Outer Barrier 
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6. MODEL DISCUSSION 
6.1 MODEL OBJECTIVES 
6.1.1 Goal of Model 
In the mill-annealed condition, Alloy 22 is primarily a single-phase, fcc solid solution with 
excellent corrosion resistance in a wide range of environmental conditions. Over time, other 
phases can precipitate out and degrade both the mechanical properties and corrosion resistance of 
the alloy. The goal of this model is to determine whether the single-phase solid solution is stable 
under repository conditions, and if not, how fast other phases may precipitate. Precipitation 
kinetics in the annealed base metal, as well as in the annealed and stress-mitigated welds, must 
be modeled. The aging and phase stability model, which is based on fundamental 
thermodynamic and kinetic concepts and principles, is used to provide predictive insight into the 
long-term metallurgical stability of Alloy 22 under relevant repository conditions. Thus, there 
are no direct inputs from this model to TSPA-LA. 
6.1.2 Background 
The time required for these precipitation reactions to occur increases as the temperature 
decreases. At the expected repository temperatures, the kinetics of these precipitation reactions 
are too slow to measure experimentally. For this reason, the rates at which they occur are 
measured at temperatures that are high in comparison to expected repository temperatures and 
then extrapolated to lower temperatures. Extrapolation from the relatively short laboratory time 
frame (tens of years) to the long repository time frame (tens of thousands of years) must be 
performed over durations spanning orders of magnitude. Calculations are used to establish 
confidence in such extended extrapolations. 
Several of the phases that form in Alloy 22 are FrankKasper, TCP phases (Shoemaker and 
Shoemaker 1988 [DIRS 154989], pp. 19 to 45, Section 4): , P, and s. These phases tend to be 
rich in Mo and/or Cr (Raghavan et al. 1984 [DIRS 154707], p. 789, Tables III and IV). Since 
these elements are largely responsible for the corrosion resistance of Alloy 22, precipitation of 
TCP phases can lead to the degradation of the corrosion properties. The TCP phases are also 
very brittle and tend to precipitate (at least initially) on grain boundaries, leading to a reduction 
in the toughness and, to a lesser extent, the ductility of Alloy 22 (Summers et al. 1999 
[DIRS 146915], pp. 922 to 923, Figures 2 and 3). 
Welding produces a cast microstructure with chemical segregation regardless of the alloy used. 
In Alloy 22, segregation of primarily molybdenum causes TCP phases to precipitate during 
welding (Cieslak et al. 1986 [DIRS 104966], p. 2041). The chemical segregation of an 
as-welded structure, as well as these TCP phases, can result in the degradation of the mechanical 
and corrosion properties of Alloy 22 welds when compared to the base metal. 
The growth of TCP phases in Alloy 22 welds due to thermal aging causes a further reduction of 
the corrosion resistance and mechanical properties of the weld. The kinetics of the reactions that 
occur in the weld may be different than those discussed above for the base metal because the 
precipitates are already nucleated in the weld and there is chemical segregation. New data 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-2 September 2004 
(Section 6.6.5.3.2) do not indicate that further nucleation and growth of TCP phases in Alloy 22 
welds will occur at temperatures below about 200C. 
6.2 FEATURES, EVENTS, AND PROCESSES (FEPS) INCLUDED IN MODEL 
This report does not provide a direct basis for the inclusion of FEP 2.1.11.06.0A (Thermal 
sensitization of waste packages) in the TSPA-LA. Rather, the results of this report are used by 
another document, General Corrosion and Localized Corrosion of Waste Package Outer 
Barrier, as reference-only information. This report provides results that show that an 
extrapolation of the aging and phase stability data (TTT diagrams) indicates that the phase 
stability of Alloy 22 base metal will not be a concern for temperatures less than 300C for 
500 years followed by a period of at least 9,500 years of less than 200C (BSC 2004 
[DIRS 169565], Figure 6.3-57). 
Table 5 indicates that only a single FEP is related to this subject and has been evaluated for 
inclusion in or exclusion from consideration in the TSPA-LA model. The same table provides a 
specific reference to the section within this report where that FEP is discussed. The detailed 
discussion of the FEP exclusionary argument is documented in FEPs Screening of Processes and 
Issues in Drip Shield and Waste Package Degradation (BSC 2004 [DIRS 169997]). 
Table 5. Features, Events, and Processes Excluded (Screened Out) in This Report 
FEP No. FEP Name Sections Where Disposition is Described 
2.1.11.06.0A Thermal sensitization of waste package 6.6.4 
6.3 AGING AND PHASE STABILITY CONCEPTUAL MODEL 
6.3.1 Phase Identification and Preliminary Kinetic Observations in Alloy 22 
Alloy 22 samples were aged for 40,000 hours at 260C, 343C, and 427C; for 30,000 hours at 
427C; for 1,000 hours at 482C, 538C and 593C; and for 16,000 hours at 593C, 649C, 
704C, and 760C before examination in TEM. A weld sample aged at 427C for 40,000 hours 
was also observed in the weld metal, in the HAZ, and in the base metal removed from the weld. 
The other samples used for the subsequent kinetic arguments were not examined in TEM. 
Several phases were observed to form in Alloy 22: P, , s, carbide, and Ni2(Cr,Mo) LRO. At 
593C, P phase was observed only on the grain boundaries. This is shown in Figure 1 through 
Figure 6. At the higher aging temperatures (up to 760C), both  and P phases precipitated on 
grain boundaries (Figure 9 through Figure 15). As the aging temperature increased, more  and 
P phase precipitation occurred within the grains. Grain boundary carbide precipitation was 
observed in samples aged at 593C and 704C (Figure 7 and Figure 8; micrographs of only 
samples aged at 593C are shown here). Because of the small amount of carbide present in these 
samples and the small volume examined in TEM, it is likely that carbides also form at 649C. 
They may or may not form at 760C. Because of the similarity between the M6C, the M12C, and 
the M23C6-type carbide crystal structures, the specific carbide forming in these samples was not 
identified; however, it is a cubic carbide with a lattice parameter of 10 to 11 . A s phase was 
observed in the samples aged at 704C and 760C (Figure 16 and Figure 17; micrographs of only 
samples aged at 760C are shown here). The amount of s observed in these samples was small 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-3 September 2004 
compared to the amount of  and P. LRO was observed in the samples aged at 593C for 16,000 
hours (Figure 45 through Figure 47) and for 1,000 hours and in the samples aged at 427C for 
40,000 hours (Figure 48 through Figure 56). These observations are summarized in Table 6. 
The results of this section have been published (Summers et al. 1999 [DIRS 110249]) and are 
consistent with other published results. For example, in Hastelloy Alloy C-276, an alloy in the 
same class as Alloy 22, mostly  and P phases were seen after aging (Leonard 1969 
[DIRS 104970], p. 228, Conclusions, point 5). Also, more  relative to P was seen in C-276 as 
aging temperature was increased (Leonard 1969 [DIRS 104970], p. 224, Table 2; 
Raghavan et al. 1982 [DIR 146956], Conclusions). In the earlier papers,  phase had not been 
named; it was called the Ni7Mo6type phase. By the time of the Raghavan et al. (1982 
[DIRS 146956]) paper, this phase had been identified as . The presence of carbides is also 
consistent with previously published results for C-276 (Raghavan et al. 1982 [DIRS 146956], 
Conclusions). The observance of LRO after aging between 427C and 593C is consistent with 
previously published occurrences of LRO in C-276 and in Alloy 22 (Tawancy et al. 1983 
[DIRS 104991], p. 40; Rebak and Koon 1998 [DIRS 102797], Figure 9 and Conclusions, 
Point 5). The presence of s phase after aging above 700C has not been previously reported in 
Alloy 22. The amount of s phase in these samples is small, and its presence is currently ignored 
(Section 5.1). 
The TEM micrographs from the samples in Section 4.1.1 were taken from samples aged for 
16,000 hours at 593C, 649C, 704C, and 760C and for 1,000 hours at 593C. Samples aged 
for shorter time intervals have not been examined in TEM; therefore, the evolution of the phases 
during aging is not known. Also, when numerous precipitates are involved, TEM diffraction 
analysis is a cumbersome method of phase identification. This is especially true when the crystal 
structures of the various phases are similar. A single SAD pattern is often not enough to 
distinguish the phases that form in Alloy 22. Instead, two patterns with a known tilt between 
them frequently must be analyzed. For this reason, little quantitative data exist for the relative 
amounts of each phase as a function of temperature. 
For this preliminary investigation, no distinction has been made between the various TCP and 
carbide phases that form. It is very difficult to distinguish these phases in SEM. It is generally 
accepted that P and  phases are similar (Leonard 1969 [DIRS 104970], p. 225; 
Raghavan et al. 1982 [DIRS 146956], p. 983, Conclusions, Point 2), and, therefore, the kinetics 
of their formation is expected to be similar. 

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ANL-EBS-MD-000002 REV 02 6-4 September 2004 
Table 6. Phases Observed in Alloy 22 in TEM 
Aging Condition Phases Observed to Form in Alloy 22 
260C for 40,000 hours 
No LRO 
No signs of grain boundary precipitation in base metal 
343C for 40,000 hours 
No LRO 
No signs of grain boundary precipitation in base metal 
427C for 30,000 hours 
LRO 
No signs of grain boundary precipitation in base metal 
427C for 40,000 hours 
LRO 
No signs of grain boundary precipitation in base metal 
482C for 1,000 hours 
No LRO 
No signs of grain boundary precipitation in base metal 
538C for 1,000 hours 
LRO 
No signs of grain boundary precipitation in base metal 
593C for 1,000 hours 
LRO 
Grain boundary films of P phase 
593C for 16,000 hours 
LRO 
Grain boundary films of P phase 
Carbide precipitates at grain boundaries 
649C for 16,000 hours 
No LRO 
Precipitation of P and  phases mainly at grain boundaries 
704C for 16,000 hours 
No LRO 
Precipitation of P and  phases at grain boundaries and within the grains 
Carbide and s precipitation at grain boundaries 
760C for 16,000 hours 
No LRO 
Precipitation of P and  phases at grain boundaries and within the grains 
s precipitation at grain boundaries 
Source: DTN: LL010107712251.012 [DIRS 155299]. 
6.3.2 Kinetics of Phase Transformations in Alloy 22 
Modeling was performed to determine the phase diagrams and other thermodynamic properties 
of the phases that form in Alloy 22 and to calculate the rate at which the relevant phase 
transformations occur (Turchi 2001 [DIRS 154934]). 
The stability of the binary alloys (nickelchromium, nickelmolybdenum, and molybdenum 
chromium) and the stability of the ternary nickelchromiummolybdenum alloys was 
investigated. The study also focused on the role of additional solutes (i.e., silicon, carbon, 
cobalt, neodymium, tantalum, and tungsten) on stability, ordering, and precipitation in Alloy 22. 
These results indicate that the TCP phases (P and probably ) are stable at repository 
temperatures and will form if they are not kinetically inhibited (Section 6.6.4). It is also apparent 
that preparing samples for measurements of the corrosion and mechanical properties must be 
done considering the temperature range at which the relevant phases form. The phases 
that would be stable under proposed repository conditions form at temperatures below 
approximately 800C. The s phase forms at higher temperatures, but it is not stable at the lower 
temperatures expected in the proposed repository. 

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ANL-EBS-MD-000002 REV 02 6-5 September 2004 
Kinetic and thermodynamic modeling are combined and applied to the study of diffusioncontrolled 
transformations. These kinetic studies were focused on the time-dependent formation 
of complex TCP phases and LRO in terms of phase evolution from the fcc matrix for times up 
to 10,000 years. The approach used in the kinetic and thermodynamic modeling involved 
simulating the Ni-Cr-Mo-W alloy system with a series of increasingly more complex 
calculations. A first series of calculations has been performed to predict the TTT diagram for the 
case of the 10% transformation of an fccbased nickelchromium matrix in the ordered Ni2Cr 
phase where experimental results were available for comparison (Karmazin 1982 
[DIRS 154881]). A second series of simulations were conducted with a pseudo-binary 
NiX(Cr3Mo)1X alloy in which kinetic data are available for comparison from the experimental 
work of Karmazin et al. (1994 [DIRS 161444]). A third series of simulations was performed 
for the case of a ternary nickelchromiummolybdenum alloy with a nominal composition of 
Ni21.1Cr13.5Mo (wt %). The transformations of P, s, and oP6 (ordered) phases from the 
fcc-based matrix ranging from 2% to 15% were each considered as a function of time and 
temperature. In these simulations, grain boundary formation is not considered. Precipitation on 
grain boundaries, which is observed, occurs at a faster rate than bulk precipitation, which was 
treated here. The results of these simulations are given in Section 6.6.4, and the validation of 
these simulations is described in Sections 7.1 through 7.4. 
6.3.3 Weld Characteristics 
The HAZ of a weld is the region of the base metal near the weld that is subjected to a significant 
thermal pulse during the welding process. TCP-precipitation kinetics in the HAZ will be similar 
to those in the base metal, but the actual rates of precipitation may be different. The high 
temperatures (approaching the melting point) seen in the HAZ of welds may trigger nucleation of 
TCP and carbide precipitates. If nuclei are already present, precipitation will proceed much 
faster than in the base metal where they are not present. 
Very few precipitates have been observed in the HAZ of weld samples thus far (Figure 41), but 
only two weld samples have been examined: one in the as-welded condition and one after aging 
at 427C for 40,000 hours. These precipitates may simply be carbides that were present in the 
mill-annealed (i.e., as-received) condition. Carbides are known to be present in Nibase alloys 
similar to Alloy 22, but they are usually within the grains and are generally called primary 
carbides to distinguish them from other secondary phases that form, often on grain boundaries, 
after an aging treatment (Tawancy et al. 1983 [DIRS 104991], p. 40). The particle in Figure 44 
was not identified but could be one of these primary carbides. 
Welding causes melting of the alloy and the development of an as-cast structure upon cooling. 
The dendritic structure typical of welds can be seen in Figure 35 through Figure 40. As an 
Alloy 22 weld solidifies, Mo and Cr are rejected from the solid phase, causing their 
concentration to increase in the liquid (Figure 74). Therefore, the interdendritic regions, which 
are the last solids to form in a weld, tend to have high concentrations of these elements relative 
to typical values for Alloy 22 (Cieslak et al. 1986 [DIRS 104966], p. 2,039, Figure 7). Because 
formation of the TCP phases, which are also enriched in Mo or Cr, is favored by higher Mo and 
Cr concentrations, these phases are present in the interdendritic regions of Alloy 22 welds. TCP 
particles can be seen in Figure 37. P phase is primarily seen in the as-welded condition of 
Alloy 22 welds, but s and  phases are also seen (Cieslak et al. 1986 [DIRS 104966], p. 2,041). 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-6 September 2004 
Only one particle was seen in TEM in an Alloy 22 weld (Figure 42 and Figure 43); this particle 
could be indexed as either P or s phase. 
Because precipitates are present in Alloy 22 welds from the beginning, kinetics of precipitation 
is not an issue as it is in the base metal and HAZ. Whether these precipitates are stable and 
grow, or are unstable and dissolve with aging at repository-relevant temperatures must also be 
determined. In addition, for weld regions where stress mitigation techniques are used, these 
techniques may result in areas of increased cold work and, hence, dislocation density. As a 
result, the increase in dislocation density may result in faster diffusion rates for phase 
precipitation, and the effect of such faster diffusion rates under repository-relevant temperatures 
on phase kinetics must be evaluated. 
6.4 CONSIDERATION OF ALTERNATIVE CONCEPTUAL MODELS 
The martensite transformation reaction was considered as a potential alternative conceptual 
model (Table 7). The martensitic transformation is primarily driven by the difference in free 
energy as an alloy is cooled from a higher to a lower temperature. During martensitic 
transformation, the atoms in the parent-phase lattice structure are realigned into the martensiticphase 
lattice (Reed-Hill 1973 [DIRS 162684], p. 636). During the formation of martensite, no 
compositional changes occur as the parent-phase lattice is realigned into the martensitic phase. 
In addition, for the transformation reaction to proceed, diffusion in either the parent phase or 
martensitic phase is not required (Reed-Hill 1973 [DIRS 162684], p. 636). As a result, 
martensitic-transformation reactions are usually referred to as diffusionless phase 
transformations. 
Table 7. Alternative Conceptual Model Considered 
Alternative Conceptual Model Key Assumption Screening Assessment and Basis 
Martensitic transformation Analogous phasetransformation 
reaction No martensite observed in Alloy 22 
Another typical characteristic of the martensitic-transformation reaction is that it primarily 
depends on temperature change. For example, the faster the alloy is cooled, the faster the 
parentmartensitic interface moves, since the progress of the martensitic reaction is dependent on 
temperature changes that affect the free energy of the reaction (Reed-Hill 1973 [DIRS 162684], 
p. 642). 
The speed of the martensitic transformation is very rapid. It has been shown that a martensitic 
plate in steel grows in 105 to 107 seconds to its full size, at near sonic velocities (Porter and 
Easterling 1997 [DIRS 163028]). In ironnickel alloys, speeds of 800 to 1,100 m/s were 
measured in the growth of plate martensite (Porter and Easterling 1997 [DIRS 163028]). 
The martensitic-transformation reaction is widely used in industry to increase the mechanical 
properties of a variety of steels. In the family of controlled-transformation steels, the typical 
microstructure of fine lath martensite with a possible fine network of d-ferrite, in combination 
with work hardening and tempering, provides these steels with strengths up to 1,500 MPa 
(Pickering 1976 [DIRS 161275]). Examples of controlled-transformation steels are known as 
transformation-induced plasticity (TRIP) steels, where deformation induces the martensitic 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-7 September 2004 
transformation (Porter and Easterling 1997 [DIRS 163029]). Common uses of TRIP steels 
include high-impact barriers or shields and automotive crash safety components (e.g., door 
impact bars). 
The shape memory alloy, Nitinol (TiNi), has a microstructure of very fine twinned martensite, 
which allows this alloy to undergo large amounts of deformation. For example, the alloy may be 
formed in a fully reversible manner when deformation occurs below the martensite initiation 
temperature. Subsequent heating of the alloy above the martensite initiation temperature restores 
the deformed structure back to its original shape (Porter and Easterling 1997 [DIRS 163029]). 
Commercial applications of Nitinol include cellular phone antennas, heart valve sizer tools, 
eyeglass frames, and spinal vertebrae spacers. 
The martensitic-transformation reaction is a well-understood and widely used model for phase 
transformation. Thus, it has been considered as an alternative conceptual model for the phase 
transformation for Alloy 22. However, in experimental results that span a wide range of 
temperatures and time periods, no martensite has been observed to form in Alloy 22. Due to its 
inherent characteristics (e.g., temperature change-dependent reaction and extreme rapid 
formation times), if martensite were to form in Alloy 22, it would have been easily observed in 
the tests conducted. As a result, the martensitic phase is not applicable to Alloy 22 phase 
transformations and, therefore, the alternative conceptual model using the martensitictransformation 
reaction is screened out from further consideration. 
6.5 MODEL FORMULATION 
6.5.1 Background and Methodology 
Thermo-Calc and DICTRA are based on the so-called CALPHAD (CALculation of PhAse 
Diagrams) approach (Saunders and Miodownik 1998 [DIRS 104975]; Spencer 1999 
[DIRS 161436]; Small 1999 [DIRS 163389]; Sundman and Agren 1999 [DIRS 163391]; 
Tanaka et al. 1999 [DIRS 163393]), introduced in the 1970s by Larry Kaufman, that involves the 
coupling of phase diagrams calculations for multicomponent alloy systems with other forms of 
thermo-chemical inputs to determine phase formation, proportions, and transformations. 
Even in binary alloy systems, difficulties often occur in determining phase formation 
characteristics solely by reference to an experimentally determined phase diagram. These 
difficulties arise from kinetic limitations on reaching equilibrium at low temperatures and from 
inherent limitations on the accuracy of some of the available experimental techniques. One of 
the major steps in the Thermo-Calc application is a full characterization of a phase diagram that 
includes all available thermodynamic information. This, in turn, offers a reliable overall 
assessment that also allows the calculation of ancillary properties from the same database. In 
analyzing higher-order multicomponent alloys, the Thermo-Calc application avoids 
thermodynamic inconsistencies with built-in safeguards, which ensure phase boundaries are 
developed in accordance with the fundamental rules of classical thermodynamics. 
DICTRA fulfills the need to provide critical modeling and analysis of data by solving the 
diffusion equations, calculating thermodynamic equilibrium (with Thermo-Calc), solving the 
flux-balance equations, and finally predicting the displacement of phase-interface positions. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-8 September 2004 
This application is used to analyze the kinetics of phase evolution in alloys selected for the 
barriers of the waste package by predicting TTT diagrams for relevant phases forming as 
functions of time. This application also will help determine the solidification path and the effect 
of welding, and eventually post-annealing, on the stability and long-term aging of alloys selected 
for the waste package. Kinetics studies are focusing on the time-dependent formation of 
complex FrankKasper phases (such as P and s phases), and the long-range ordering in terms of 
phase evolution from the fcc matrix with times of at least 10,000 years. The DICTRA 
application can also be applied to the study of grain boundary formation of carbides, silicides, 
and TCP phases and phase evolution under non-isothermal conditions, as is the case during 
welding. 
Starting with the thermo-chemical database provided by the SGTE (Scientific Group Thermodata 
Europe) data group, a detailed analysis of the stability of the binary alloys NiCr, NiMo, and 
MoCr, and of the ternary NiCrMo alloys was undertaken, since the databases included with 
the software were not optimally configured for Ni-Cr-Mo-W alloy studies. The study then 
focused on the role of additional solutes such as Si, C, Co, Nb, Ta, and W on stability, ordering, 
and precipitation in NiCrMo-based alloys. Finally, kinetic and thermodynamic modeling have 
been combined and applied to the study of diffusion-controlled transformations with the use of 
the DICTRA software linked to Thermo-Calc. 
6.5.2 Solidification According to the Scheil-Gulliver Approach 
In all practical cases, solidification during most processing routes occurs in a non-equilibrium 
manner and gives rise to significant variations in the chemistry and the occurrence of secondary 
phases. Using a CALPHAD approach based on Scheil-Gulliver simulations, solidification can 
be studied, and predictions on the amount of undercooling can be made (Saunders and 
Miodownik 1998 [DIRS 104975]). Within this approach, a liquid of composition c0 is cooled to 
a small amount below its liquidus temperature T1. The solid precipitates out of the liquid with a 
composition S 
1 c whereas the composition of the liquid becomes L 
1 c . On further cooling to the 
temperature T2, the initial solid cannot change its composition (since back-diffusion in the solid 
phase in neglected in this approach). A local equilibrium is then established, and the liquid of 
composition L 
1 c transforms to a liquid of composition L
2 c , and a solid with composition, and the 
process is repeated upon further cooling (Figure 74). As solidification proceeds, the solid 
becomes lean in solute in the center of the dendrite whereas the liquid is enriched in solute until 
the composition of the liquid reaches the eutectic composition, and solidification is finally 
completed. Within the Thermo-Calc application software, the Scheil module is available to 
perform these simulations. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-9 September 2004 
Source: Saunders and Miodownik 1998 [DIRS 104975]. 
Figure 74. Schematic Description of Solidification According to the Scheil-Gulliver Approach 
6.5.3 Computer Coupling of Phase Diagrams and Thermochemistry 
Computer coupling of phase diagrams and thermochemistry (CALPHAD) is capable of 
predicting the phase behavior in experimentally uninvestigated regions of a multicomponent 
system by extrapolating from their lower-order systems. 
The equations and diagram presented in this section have been formulated and formatted for 
clarity by Turchi (2003 [DIRS 162974]) and are a synthesis of information from the cited 
references and the Thermo-Calc and DICTRA software documentation. These equations and 
diagrams are included here to aid in understanding the CALPHAD approach to computational 
thermodynamics and phase kinetics. 
In the CALPHAD approach, the Gibbs energy of individual phases is modeled, and the model 
parameters are collected in a thermodynamic database. It is the modeling of the Gibbs energy of 
individual phases and the coupling of phase diagram and thermochemistry that make the 
CALPHAD a powerful technique in computational thermodynamics of multicomponent 
materials. Models for the Gibbs energy are based on the crystal structures of the phases. For 
pure elements and stoichiometric compounds, the most commonly used model is the one 
suggested by the Scientific Group Thermodata Europe (SGTE) and has the following form as 
presented by Saunders and Miodownik (1998 [DIRS 104975], Equation 5.3) (for simplicity, the 
pressure dependence and the magnetic contribution are not shown here), 
. + + + = - i 
i T d T cT bT a H G ) ( ln SER 
m m (Eq. 1) 
The left-hand side of the equation is defined as the Gibbs energy relative to a standard element 
reference (SER) state, where SER 
m H is the enthalpy of the element in its stable state at 298.15C. 
Coefficients, a, b, c, and di are the model parameters. The SGTE data for pure elements have 
been compiled by Dinsdale (1991 [DIRS 161439]). 

Aging and Phase Stability of Waste Package Outer Barrier 
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For multicomponent solution phases, the Gibbs energy has the following general formula, as 
presented by Saunders and Miodownik (1998 [DIRS 104975], Equation 5.1): 
xs 
mix 
ideal 
mix 
o G G G G + + = (Eq. 2) 
where 
o G is the contribution from the mechanical mixing of pure components 
ideal 
mix G the ideal mixing contribution 
xs 
mix G is the excess Gibbs energy of mixing due to non-ideal interactions 
Sublattice models have been widely used to describe solution phases (Sundman and Agren 1981 
[DIRS 161460]; Andersson et al. 1986 [DIRS 161461]; Ansara et al. 1998 [DIRS 161462]). For 
example, for a simple phase with two sublattices in an A-B binary system where both 
components enter both sublattices, the sublattice model is written as (A,B)p(A,B)q, where the 
subscripts p and q denote the number of sites of each sublattice, respectively. The three terms in 
Equation 2 are written as (based on the formulation presented by Saunders and Miodownik 1998 
[DIRS 104975], Equations 5.30, 5.29, 5.33, and 5.34): 
o 
B : B 
II 
B 
IB 
o 
A : B 
II 
A 
IB 
o 
B : A 
II 
B 
IA 
o 
A : A 
II 
A 
IA 
o G y y G y y G y y G y y G + + + = (Eq. 3) 
( ) ( ) II 
B 
II 
B 
II 
A 
II 
A 
IB 
IB 
IA 
IA 
ideal 
mix ln ln ln ln y y y y qRT y y y y pRT G + + + = (Eq. 4) 
.. 
. 
.. 
. 
- + - = . . 
= = 0 
IB 
IA
B : B A, 
II 
B 
0 
IB 
IA
A : B A, 
II 
A 
IB 
IA 
xs 
mix ) ( ) ( 
k 
k k 
k 
k k y y L y y y L y y y G 
.. 
. 
.. 
. 
- + - + . . 
= = 0 
II 
B 
II 
A B A, : B 
IB
0 
II 
B 
II 
A B A, : A 
IA 
II 
B 
II 
A ) ( ) ( 
k 
k k 
k 
k k y y L y y y L y y y (Eq. 5) 
where 
yI and yII are the site fractions of A or B in the first and second sublattices, respectively 
o
J : I G is the Gibbs energy of the compound IpJq, expressed by Equation 1 
k L * : B A, ( k L B A, : * ) is the kth order interaction parameter between component A and B in the 
first (second) sublattice 
In this notation, a colon separates components occupying different sublattices, and a comma 
separates interacting components in the same sublattice. These equations can be generalized for 
phases with multicomponents and multisublattices, and they reduce to a random substitutional 
model when there is only one sublattice. 

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For a multicomponent solution in a particular phase F described with a single sublattice model, 
the three contributions to the total Gibbs energy reduce to (based on the formulation by Saunders 
and Miodownik 1998 [DIRS 104975], Equation 5.21): 
o
I 
I 
I 
o G c G F F . = 
I 
I 
I 
ideal 
mix c c RT G ln . = F (Eq. 6) 
( )k 
J I 
k 
k 
J I 
I 
J 
I J 
I 
xs 
mix c c L c c G - = . .. F 
> 
F 
, 
where the molar Gibbs energy of mixing is expressed by a Redlich-Kister expansion 
(Redlich et al. 1948 [DIRS 161464]). In these expressions c
I is the composition of the alloy in 
species I, and k 
J I L , is the kth-order binary interaction parameter between species I and J expressed 
as a polynomial in temperature, T. Note in both sets of expressions the excess Gibbs energy due 
to nonideal contributions is given by the Muggianu equation (Saunders and Miodownik 1998 
[DIRS 104975], Eq. 5.22). 
Thermodynamic modeling begins with the evalution of thermodynamic descriptions of unit and 
binary systems. By combining the thermodynamic descriptions of consititutive binary systems 
and ternary experimental data, the thermodynamic descriptions of ternary systems are developed 
and so forth. These descriptions cover the whole composition and temperature ranges, including 
the experimentally uninvestigated regions. For this work, the original SSOL thermodynamic 
database has been developed using the CALPHAD technique. Thermo-Calc, the most general 
and powerful program in computational thermodynamics of multicomponent alloys (Saunders 
and Miodownik 1998 [DIRS 104975], Spencer 1999 [DIRS 161436]; Small et al. 1999 
[DIRS 163389]; Bernard et al. 1999 [DIRS 163390]; Sundman et al. 1999 [DIRS 163391]; 
Spear et al. 1999 [DIRS 163392]; Tanaka et al. 1999 [DIRS 163393]), is then used. 
The CALPHAD approach is, in fact, the most successful method to address specific materials 
questions of practical importance to industry and technology (Spencer 1999 [DIRS 161436]; 
Small et al. 1999 [DIRS 163389]; Bernard et al. 1999 [DIRS 163390]; Sundman et al. 1999 
[DIRS 163391]; Spear et al. 1999 [DIRS 163392]; Tanaka et al. 1999 [DIRS 163393]). 
6.5.4 Diffusion Modeling in Phase Transformations 
Process simulations require the development of the kinetic description of alloy systems, that is, 
the mobility of species in individual phases (Saunders and Miodownik 1998 [DIRS 104975]; 
Spencer 1999 [DIRS 161436]; Small et al. 1999 [DIRS 163389]; Sundman et al. 1999 
[DIRS 163391]; Engstrm et al. 1994 [DIRS 161442]; Agren 1992 [DIRS 161440]). The models 
relating the mobility and diffusivity are based on the generalized Onsager flux equation. 
For example, for a phase consisting of a substitutional sublattice and an interstitial sublattice, the 
intrinsic diffusion coefficient, Dkj (the diffusivity of component k with respect to the gradient of 

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component j), is related to the atomic mobility Mi (i for all the elements in a phase) with the 
following formula (based on the formulation by Agren (1992 [DIRS 161440])): 
( ) . . 
. . .
. + 
.
. - = 
S i j
i 
i Va i ik 
S i j
i 
i i k ik kj u 
M y u 
u 
M u u D  d  d (Eq. 7) 
with 
uk = 
xk
xi 
i.S . 
and k i 
k i ik 
=
. = 1 
0 { d 
where 
i.S denotes that component i is substitutional and i.S denotes that component i is 
interstitial 
xk is the mole fraction of component k 
i is the chemical potential of component i derived from the Gibbs energy of the phase 
yVa represents the site fraction of vacancy in the interstitial sublattice 
ik d is the Kronecker delta 
The mobility Mi associated with species i is further related to a frequency factor 0 
i M and 
composition with the following equations, as presented in the DICTRA Users Guide (Thermo- 
Calc Software 1998 [DIRS 162973]): 
.. 
. 
.. 
. . = 
RT
G 
RT 
M M i i 
i exp 
0 
(Eq. 8) 
.. . ... .. 
> > 
. + . + . = . 
j n n m 
m n j 
i m n j 
j j k m 
m k j 
i m k j 
j m 
m j 
i m j i G y y y G y y y G y y G , : II II I : , II I I : II I (Eq. 9) 
where 
i G . is the activation Gibbs energy of component i 
m j 
i G : . is the activation Gibbs energy of component i with components j and m on the 
first and second sublattices, respectively 
This formulation for a ternary system is based on the binary system formulation presented in 
Equation 5.37 of CALPHAD, Calculation of Phase Diagrams: A Comprehensive Guide 
(Saunders and Miodownik 1998 [DIRS 104975]). The interaction terms, m k j 
i G : , . and m n j 
i G , : . , 
are expressed with a polynomial similar to the summations in Equation 3. The individual 
parameters are evaluated from chemical and tracer diffusion data. 
By combining thermodynamic and kinetic descriptions of alloy systems, phase transformations 
can then be simulated. The schematic flow chart of the DICTRA simulation is shown in 
Figure 75 (Turchi 2003 [DIRS 162974]). The most significant feature of this simulation 
procedure is the simultaneously coupling of thermodynamics and kinetics. 

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Figure 75. Schematic Flow Chart of Numerical Simulation of Phase Transformations 
6.6 MODEL RESULTS 
The model results are presented in two parts: computational and experimental. The 
computational results were conducted in three general steps: (1) development of the 
Thermo-Calc results for the alloy systems and components of interest (Sections 7.1 through 7.4), 
(2) determination of the property diagrams for the Ni-based alloys of interest (Section 6.6.1), and 
(3) determination of the kinetic properties (TTT diagrams) of the Ni-based alloys of interest 
(Section 6.6.2). The experimental results are presented in three areas: (1) volume-fraction 
measurements in Alloy 22 base metal, including grain boundaries (Section 6.6.5.1); (2) volumefraction 
measurements in Alloy 22 weld metal (Section 6.6.5.2); and (3) microhardness 
measurements in Alloy 22 base metal, which are indicative of LRO (Section 6.6.4). 
The validation of the computational phase diagrams and kinetic results with published data 
measured are described in detail in Sections 7.1 through 7.4. 
6.6.1 Property Diagrams of the Ni-Based Alloys 
The property diagrams of various Ni-based alloys were calculated using Thermo-Calc at their 
nominal alloy composition as indicated in Table 8. These diagrams display the phase (or 
volume) fractions as a function of temperature. 
Gibbs 
Energy 
.2G 
.xi.x j 
THERMODYNAMICS DATABASE KINETICS 
Interfacial 
Equilibrium 
Solve 
Flux Balance 
Kinetic 
Coefficients 
Solve 
Diffusion Equations 
Rate of 
Reaction

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Table 8. Nominal Chemical Compositions of Ni-Cr-Mo Alloys 
Alloy 
Ni 
(balance) 
Cr 
(wt %) 
Mo 
(wt %) 
Fe 
(wt %) 
W 
(wt %) 
Mn 
(wt %) 
C 
(wt %) 
Other 
(wt %) 
C-276 57 14.5 to 16.5 15 to 17 4 to 7 3 to 4.5 1.0 0.02 Co: 2.5 (max) 
C-4 53 14 to 18 14 to 17 3 (max) - 1.0 0.015 Co: 2.0 (max) 
59 59 22 to 24 15 to 16.5 1.5 
(max) 
- 0.5 0.01 Al: 0.1 to 0.4 
22 56 20 to 22.5 12.5 to 14.5 2 to 6 2.5 to 3.5 0.5 0.015 Co: 2.5 (max) 
Source: Turchi 2003 [DIRS 162974]. 
6.6.1.1 Alloy 22 
In the case of Alloy 22, the Thermo-Calc results shown in Figure 76 (left and central panels) 
confirm, that at equilibrium and low temperature, a three-phase field that includes the Ni2Cr-type 
of ordered phase (or oP6), a complex TCP structure (P phase, or similar such as ), and the fcc 
matrix should exist. It is interesting to note in Figure 76 (right panel) if the P phase is suspended 
during the calculation of the property diagram (suspending a phase is analogous to assuming that 
the phase is not kinetically favored), the domain of stability of the s phase extends in a broader 
range of temperatures towards low temperatures from 930C to 448C (instead of 802C). Also, 
the ordered phase of Ni2Cr-type (oP6) competes with the P phase, as illustrated in Figure 77. 
Whereas oP6 is itself stable up to 566C (all phases suspended except fcc and oP6), the complete 
property diagram indicates a maximum temperature of stability at about 408C. Finally, at low 
phase fraction, a number of carbides and silicides are stable, namely: M7C3, V3C2, and Cr3Si. It 
is likely that these precipitate phases will preferably form in the proximity of the grain 
boundaries, where C and Si are usually observed. 
Source: DTN: LL030106312251.013. 
NOTE: In the left panel, the diagram in the whole range of phase fraction is displayed, whereas in the central 
panel a detailed description of the diagram clearly shows the phases that occur at low phase fraction. The 
right panel is the property diagram of Alloy 22 in the case the P phase is not considered in (i.e., suspended 
during) the calculations. 
Figure 76. Calculated Property Diagrams of Alloy 22 

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Figure 77. Calculated Property Diagrams of Alloy 22 with the Liquid, the fcc Matrix, and the s Phase 
(Left Panel), the P Phase (Central Panel), and the oP6-ordered Phase (Right Panel) 
Considered in the Calculations 
By retaining the liquid phase and the fcc matrix, and s phase, P phase, or oP6-ordered phase 
during the calculation of the property diagram, the domain of existence of s, P or oP6 with 
respect to fcc can be easily evaluated, as shown in Figure 77. For example, with no other 
competing phases than the fcc, the s phase exhibits a broad domain of stability that is limited at 
low temperature when the oP6 is reintroduced in the calculations (Figure 76, right panel), and 
even more so when the P phase is allowed (Figure 76, left panel). Hence, it can be concluded 
that under particular circumstances where metastability can be promoted, the s phase can be 
found at temperature lower than the one predicted at equilibrium. 
In Figure 78, the analysis in terms of weight fraction as a function of temperature of each major 
element (Ni, Cr, or Mo), and W and Fe (when present) for each individual phase, namely the fcc 
matrix, the oP6-ordered phase, and the two TCP phases, P and s, confirms the expectation. 
Indeed, in the TCP phases, a noticeable depletion in Ni and an enhancement in Cr in the P phase 
or Mo in the s phase in their temperature range of stability (indicated by the horizontal line with 
arrows on both ends) are observed in Figure 78 (bottom panels). In the case of the oP6-ordered 
phase, a depletion in Ni and a noticeable departure from the nominal Cr and Mo compositions 
are observed (Figure 78, top right panel). It may be necessary to revisit these predictions in the 
case of welding where alloy stability can be affected by the presence of TCP phases and of the 
oP6-ordered phase at compositions that strongly depart from the nominal composition of 
Alloy 22. 

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NOTE: The horizontal line with arrows on both ends indicates the domain of stability of the phase whereas the 
stand-alone vertical line indicates the temperature at which the phase starts occurring. 
Figure 78. Weight Fraction of Ni (Red), Cr (Blue), Mo (Green), W (Brown), and Fe (Black), Versus 
Temperature in the fcc Matrix, the oP6, and the P and s Phases for Alloy 22 at its Nominal 
Composition 
6.6.1.2 Alloy C-4 
The calculated property diagram for Alloy C-4 is shown in Figure 79. In the case of alloy C-4, 
the main phases forming, besides the fcc matrix, are the P and the Ni2Cr-type (oP6) phases. In 
addition, the M23C6 and the A15 Cr3Si-type phases form at very low phase fraction. The 
relatively low Cr content in this alloy excludes the formation of the s phase. 

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NOTE: Additional phases (mostly carbides and silicides) predicted with a phase fraction less than 0.01 are not 
reported. 
Figure 79. Calculated Property Diagrams (Phase Fraction Versus Temperature) of Alloy 22, 
Alloy 59, C-4, and C-276 at Their Nominal Composition 
6.6.1.3 Alloy C-276 
The calculated property diagram for Alloy C-276 is shown in Figure 79. In the case of 
Alloy 276, as in the case of Alloy C-4, the low Cr and Mo content significantly reduces the 
formation of the s phase and prevents the formation of the Ni2Cr-type (oP6) ordered phase. 
Because of the presence of C and Si, the A15 Cr3Si-type and M23C6 phases are found in this 
alloy. 

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6.6.1.4 Alloy 59 
The calculated property diagram for Alloy 59 is shown in Figure 79. In the case of Alloy 59, the 
P phase forms in a broader range of temperature (up to about 900C) than in Alloy 22 (811C); 
this can be attributed to a higher Cr and Mo content in Alloy 59 than in Alloy 22. Once again, at 
very low phase fraction, the A15 Cr3Si-type and M7C3 phases are stable. 
6.6.2 Equivalent Alloys 22, 59, C-4, and C-276 
A definition for the equivalent composition of Ni, Cr, and Mo has been used (Section 7.3) that is 
usually considered when discussing alloy stability in Ni-based alloys (Cieslak et al. 1982 
[DIRS 104966]. Using these equivalents, compositions of the property diagrams of the 
equivalent Alloy 22, 59, C-4, and C-276 compositions have been calculated and the results are 
displayed in Figure 80. The results are directly comparable to those displayed in Figure 79. 
Significant differences are noted. For example, in all cases the alloys at their equivalent 
compositions display an oP6-ordered phase with a larger volume fraction and stabilize at much 
higher temperature than in the corresponding alloys at their nominal composition. This enhanced 
stability of the oP6 phase is due to a destabilization of the P phase at low temperature. Also, the 
s phase is no longer stable in all four cases. Hence, extreme caution must be taken when basing 
arguments based on Cr, Mo, and Ni equivalents. 

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NOTE: Additional phases (mostly carbides and silicides) predicted with a phase fraction less than 0.01, are not 
indicated in the diagrams. 
Figure 80. Property Diagrams (Phase Fraction Versus Temperature) of the Equivalents of Alloy 22, 
59, C-4, and C-276 at their Nominal Composition 
6.6.3 Scheil-Gulliver Simulation of Solidification Processes in Ni-Based Alloys 
Most of the Ni-based alloys display a fair amount of under-cooling, of the order of 140C 
(e.g., 133C, 127C, 150C, and 150C for Alloy 22, Alloy 59, C-4, and C-276, respectively), 
and this result has been confirmed with Scheil-Gulliver simulations (Figure 81). From the liquid 
phase, the first solid phase to occur in all alloy cases is the fcc matrix, and then a small fraction 
of A15-based Cr3Si compound starts forming. The last phase to form under the Scheil-Gulliver 
conditions (that assume local equilibrium, infinite diffusion in the liquid phase, and no back 

Aging and Phase Stability of Waste Package Outer Barrier 
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diffusion in the solid phase) is the s phase (except for C-4 and C-276), and the under-cooling is 
accompanied by a decrease in Ni content and an increase in Mo and Cr contents from the 
nominal composition (Figure 78, bottom right panel in the base-metal case) and Figure 82. 
These results clearly indicate that the alloys of this series (at their nominal compositions) can be 
properly annealed in a relatively broad region of temperature and quenched to retain the single 
fcc phase. 
The transition temperatures are determined during the execution of the Scheil-Gulliver 
simulations and have been added onto the plots of Figure 81 for clarity. 
Source: DTN: LL030106312251.013. 
Figure 81. Scheil-Gulliver Simulation Results for Alloy 22, Alloy 59, C-4, and C-276: Temperature 
Versus Weight Fraction of Solid Phase that Describes the Amount of Under-Cooling and 
the Succession of Phases During Cooling 

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Figure 82. Scheil-Gulliver Simulation Results of Weight Fraction of Ni (Red), Cr (Blue), and Mo 
(Green) in the fcc Matrix for Alloy 22, Alloy 59, C-4, and C-276 as Functions of 
Temperature, During Solidification 
6.6.4 Kinetic Properties of Nickel-Based Alloys 
Kinetic and thermodynamic modeling have been combined and applied to the study of diffusioncontrolled 
transformations with the use of the DICTRA application linked with Thermo-Calc. 
Simulations have been performed on three alloy systems, in order of increasing complexity: (1) a 
binary NiCr alloy, (2) a pseudo-binary NiX(Cr3Mo)1X alloy, and (3) a ternary NiCrMo alloy 
that can be considered as a surrogate for Alloy 22, with the following nominal composition: Ni, 
21.1 Cr, and 13.5 Mo (in wt %). The TTT diagrams resulting from these simulations are 
described below. 
6.6.4.1 TTT Diagram for the fcc to Ni2Cr-Type (oP6) Ordered Phase in Ni2Cr 
A first series of calculations have been performed to predict the TTT diagram in the case of a 
10% transformation of an fcc-based NiCr solid solution to the ordered Ni2Cr (oP6) phase for 
which case experimental results were available (Karmazin 1982 [DIRS 154881]). The results are 
displayed in Figure 84. The MOB database that contains the mobility and the diffusion 
coefficient of the Cr species in an fcc-Ni matrix has been adjusted to account for the kinetics of 

Aging and Phase Stability of Waste Package Outer Barrier 
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transformation studied experimentally by Karmazin (1982 [DIRS 154881]). The variation of the 
fcc lattice parameter as a function of time at various annealing temperatures (Figure 83) is 
formulated to be directly proportional to the amount of ordered phase formed in the disordered 
fcc matrix. Based on this relation, three points of the TTT diagram have been obtained at 450C, 
500C, and 530C (Karmazin 1982 [DIRS 154881], Figure 6) in the case of a 10% 
transformation from fcc to oP6 of the Ni-rich solid solution with 33.3 at % Cr. The location of 
the nose of the experimental TTT curve has been used to determine the kinetic parameters that 
are defined in the MOB database for subsequent DICTRA calculations. The DICTRA results for 
the same rate of transformation (10%) are also displayed in Figure 84, and the shape of the 
C-curve compares very favorably with the experimentally deduced one. From the stability 
studies (Section 7.1), the value of the critical orderdisorder temperature (that positions the 
asymptote in the TTT diagram), 553C, compares very well to the experimentally assessed value 
of 540C. The transformation is rather sluggish and is initiated after about 200 hours. 
Extrapolation of the TTT curve to lower temperatures clearly indicates that in this binary alloy, 
the formation of oP6-ordered phase out of the fcc solid solution will not be a concern for 
conditions of less than 300C for a period of 500 years followed by temperatures of less than 
200C for a period of 9,500 years, conditions that bound the repository time-temperature profiles 
(BSC 2004 [DIRS 169565], Figure 6.3-57). 
Source: Karmazin 1982 [DIRS 154881], Fig. 6. 
NOTE: The horizontal lines delineate the range of existence of the oP6 long-range order (LRO) from the 
disordered phase (top line) to the fully ordered phase (bottom line). 
Figure 83. Experimental Variation of the Lattice Parameter with Time at Fixed Isothermal Annealing 
for Ni2Cr Alloy 

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NOTE: The experimentally deduced TTT diagram (blue solid squares) (Karmazin 1982 [DIRS 154881]) for the 
same transformation rate is also shown for comparison. 
Figure 84. Calculated Isothermal TTT Diagrams (Red Solid Circles) for an fcc-Based Matrix of a 
Binary Ni2Cr Alloy Transforming into the oP6-Ordered Phase, with Transformation Rate of 
10% 
6.6.4.2 TTT Diagram for the fcc to Ni2Cr-type (oP6) Ordered Phase in a Pseudo-Binary 
NiX(Cr3Mo)1X Alloy 
To make further comparisons with experimental results, a pseudo-binary NiX(Cr3Mo)1X alloy is 
considered in which kinetic data are available from the experimental work of Karmazin et al. 
(1994 [DIRS 161444]). In this study, the kinetic parameters (diffusion coefficient and mobility) 
for Mo in Ni are formulated to be identical to those of Cr in Ni. As in the previous case 
(Section 6.6.4.1), there is a linear relation between the variation of the lattice parameter and the 
amount of fcc matrix transformed into the oP6-ordered phase. In Figure 85, the property 
diagram of this alloy is displayed with only the fcc and oP6 phases included in the calculation. It 
is shown that the ordered phase is stable below 627C. Based on this assumption, the DICTRA 
results for 5%, 10%, and 15% transformation from the fcc-solid solution to oP6 for Ni-24 at % 
Cr-8 at % Mo (or 20.78 wt % Cr and 12.78 wt % Mo) are reported in Figure 86. The 
experimental point (solid square) indicated in Figure 86, representing 5% transformation, has 
been deduced from the experimental study of the variation of the lattice parameter with time 
under isothermal annealing condition shown in Figure 3 by Karmazin et al. (1994 
[DIRS 161444]; Figure 96c). The results show that, (1) the thermodynamic driving force at this 
alloy composition and the kinetic factors account fairly well for the kinetics of transformation 
and (2) although Mo enhances the stability of the ordered phase (increased critical order-disorder 
temperature at about 627C), the extrapolation of the TTT curves to lower temperatures confirms 
the observation already made in the binary case that the formation of the oP6-ordered phase out 
of the fcc-solid solution will not be a concern for conditions of less than 300C for a period of 

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500 years followed by temperatures of less than 200C for a period of 9,500 years, conditions 
that bound the repository time-temperature profiles (BSC 2004 [DIRS 169565], Figure 6.3-57). 
Source: DTN: LL030106312251.013. 
NOTE: The fcc and oP6-ordered phases are considered. All other phases are suspended during the calculations. 
Figure 85. Property Diagram of Ni-24 at % Cr-8 at % Mo (or 20.78 wt % Cr and 12.78 wt % Mo) 
Source: DTN: LL030106312251.013. 
NOTE: The black solid square indicates the results deduced from annealing experiments performed on a NiCr 
Mo alloy at the same composition presented by Karmazin et al. (1994 [DIRS 161444]). 
Figure 86. Calculated Isothermal TTT Diagrams for an fcc-Based Matrix of a Ternary Ni20.78Cr 
12.78Mo (in wt %) Cr Alloy Transforming into the oP6-Ordered Phase, with Transformation 
Rates of 5%, 10%, and 20% 

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6.6.4.3 Kinetics of Transformation in a Ni21.1 wt % Cr13.5 wt % Mo Alloy 
For this series of calculations, the nominal composition, Ni, 21.1 Cr, and 13.5 Mo (in wt %), was 
used for the ternary Ni-Cr-Mo- alloy that can be considered as a surrogate for Alloy 22. 
Three transformations were considered: the fcc matrix to the oP6-ordered phase, the fcc matrix 
to the P phase and the fcc matrix to the s phase. The corresponding property diagrams 
associated only with the fcc matrix and the transformed phase (oP6, P, or s) were considered in 
the calculations are displayed in Figure 87. In the study of the kinetics of phase formation of the 
oP6-ordered phase, 7.5 wt % Mo is used instead of 13.5 wt %. This reduction in Mo accounts 
for the role of W in destabilizing the ordered phase, and the relative contribution of W is 
approximately twice that of Mo (1 wt % W  2 wt % Mo). Details of this treatment are 
discussed in Section 7.4. 
Source: DTN: LL030106312251.013. 
NOTE: The fcc Matrix and the Op6-Ordered Phase (Left Panel; in This Case, 7.5 Wt % Mo Was Considered 
Instead of 13.5 Wt %, P Phase (Middle Panel), and s Phase (Right Panel) are Considered. All Other 
Phases are Suspended During the Calculations. 
Figure 87. Property Diagram of Ni21.1 wt % Cr13.5 wt % Mo 
In Figure 88, the TTT diagram associated with the fcc to oP6 transformation is displayed with 
2%, 10%, and 15% transformation rates. When compared with the results for the binary Ni2Cr 
alloy, the combined role of Mo and W has the effect of enhancing the critical order-disorder 
temperature from 553C to 596C. 

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Figure 88. Calculated Isothermal TTT Diagram for an fcc-Based Matrix of a Ternary Ni21.1Cr7.5Mo 
(in wt %) Alloy (Surrogate for Alloy 22) Transforming into the oP6-Ordered Phase, with 
Transformation Rates of 2%, 10%, and 15% 
The transformation from the fcc-based matrix to the P phase with 2%, 10%, and 15% 
transformation rates was considered (from left to right in Figure 89) as a function of time and 
temperature. The results are comparable with the qualitative observations cited by Turchi 2001 
([DIRS 154934]). 
The transformation from the fcc-based matrix to the s phase with 2%, 5%, and 10% 
transformation rates was simulated (from left to right in Figure 90) as a function of time and 
temperature. In contrast to the formation from the fcc-matrix to the oP6-ordered phase that is 
rather slow, the incipient formation of the P phase is quite fast (a few hours in the bulk). 
However, as was concluded previously, the extrapolation of these TTT curves to lower 
temperatures clearly indicates that formation of the P phase out of the fcc-solid solution will not 
be a concern for conditions of less than 300C for a period of 500 years followed by 
temperatures of less than 200C for a period of 9,500 years, conditions that bound the repository 
time-temperature profiles (BSC 2004 [DIRS 169565], Figure 6.3-57). 

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Figure 89. Calculated Isothermal TTT Diagram for an fcc-Based Matrix of a Ternary Ni-21.1Cr-13.5Mo 
(in wt %) Alloy (Surrogate for Alloy 22) Transforming into the P Phase, with Transformation 
Rates of 2%, 10%, and 15% 
It should be noted that in the computational TTT diagrams presented in this section using the 
ternary Ni-Cr-Mo alloy (a surrogate for Alloy 22), the effects of Ni, Cr, Mo, and W (the 
elements that contribute most significantly to Alloy 22 phase stability) are included in the 
computational simulations. Although other elements in the Alloy 22 compositional specification 
may affect Alloy 22 phase phenomena, these elements are presently not modeled in the ternary 
Ni-Cr-Mo alloy. Also, in these calculations, grain boundary formation is not considered; that is, 
the results only apply to bulk formation and homogeneous-phase evolution. 

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ANL-EBS-MD-000002 REV 02 6-28 September 2004 
Source: DTN: LL030106312251.013. 
Figure 90. Calculated Isothermal TTT Diagrams for an fcc-Based Matrix of a Ternary 
Ni-21.1Cr-13.5Mo (in wt %) Alloy (Surrogate for Alloy 22) Transforming into the s Phase, 
with Transformation Rates of 2%, 5%, and 10% 
6.6.5 Volume-Fraction Measurements in Alloy 22 
In order to measure the amount of TCP-phase precipitation in Alloy 22 base metal and welds, 
area-fraction measurements have been made, using SEM image analyses, as a function of aging 
time and temperature. Using standard methods of quantitative stereology, it has been shown that 
area-fraction measurements (and correspondingly, linear-fraction measurements on grain 
boundaries) are mathematically equivalent to volume-fraction measurements 
(Vander Voort 2000 [DIRS 161300]; Hilliard and Cahn 1961 [DIRS 161454]). Thus, the 
area-fraction measurements presented in this report are equivalent to the volume-fraction values 
in Alloy 22 as a function of time and temperature. 
The SEM image analyses that were performed measured gross TCP-phase precipitation in the 
samples as a function of time and temperature. No TCP-phase extraction was conducted to 
differentiate the types of TCP phases that may be present (e.g.,  or P phases) in these 
measurements. 
6.6.5.1 Area-Coverage Measurements on Grain Boundaries 
Similar to the area-fraction measurements on base metal samples, area-coverage measurements 
(linear-fraction measurements) on grain boundaries have been performed using SEM image 
analyses. Again, using standard methods of quantitative stereology, these linear-fraction 
measurements of TCP-phase precipitation on grain boundaries are mathematically equivalent to 
volume-fraction measurements (Vander Voort 2000 [DIRS 161300]; Hilliard and Cahn 1961 
[DIRS 161454]). Figure 91 summarizes the grain-boundary measurements shown in Table 3. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-29 September 2004 
Source: DTN: LL030606912251.020. 
Figure 91. TCP Phase Precipitation on Alloy 22 Grain Boundaries as a Function of Time and 
Temperature 
Due to the paucity of available grain coverage data (as shown in Figure 91), only a few 
observations regarding TCP phase precipitation on grain boundaries are noted. Similar to 
TCP-phase precipitation in base metal, TCP-phase precipitation on grain boundaries is dependent 
on temperature. The onset of TCP-phase precipitation on grain boundaries appears to be delayed 
with decreasing temperature. 
6.6.5.1.1 Estimation of Bounding Case for TCP Phase Precipitation on Grain 
Boundaries 
Until more measurements of TCP-phase precipitation on grain boundaries or the corresponding 
results from computational modeling are available, a bounding case of TCP-phase precipitation 
on grain boundaries can be formulated from the grain-boundary precipitation measurements. 
Nucleation and growth kinetics can often be represented by an equation of the following form: 
f =1-exp(-ktn ) (Eq. 9) 
where f is the volume fraction of the precipitating phase, t is the time at the aging temperature, 
and k and n are constants (Christian 1981 [DIRS 104964], p. 19, Equation 4.11). The value of k 
depends on nucleation and growth rates and therefore depends very strongly on temperature, 
usually of the following form: 
k = C1 exp(-C2 /T) (Eq. 10) 
where C1 and C2 are constants and T is the temperature (e.g., Christian 1981 [DIRS 104964], 
p. 438, Equation 49.2, where the exponentials representing atomic vibrational frequency and 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 6-30 September 2004 
activation energy for an elementary atomic movement have been combined). Ideally, the volume 
fraction of precipitation would be measured as a function of time and temperature and would be 
fit to Equation 9. Precipitation times can be fit to Equation 9 if it is modified for a constant 
volume fraction. Combining Equations 9 and 10 at constant volume fraction yields: 
ln t f ( )= 
C2 
n 
 
1
T 
+Cf (Eq. 11) 
where Cf is a constant containing the constant volume fraction term, f, from Equation 9. 
Equation 11 is of the usual linear form, y=mx+b, representing ln(tf) as a function of 1/T. Plots of 
log(time) versus reciprocal temperature for 20% and 80% grain boundary coverage are shown in 
Figure 92. 
y = 6E-20e45488x 
R2 = 0.9949 
y = 2E-19e45488x 
R2 = 0.9949 
1.E-01 
1.E+00 
1.E+01 
1.E+02 
1.E+03 
1.E+04 
1.E+05 
1.E+06 
1.E+07 
1.E+08 
0.0009 0.0011 0.0013 0.0015 0.0017 0.0019 0.0021 
Reciprocal Temperature (1/K) 
Aging Time (hr) 
20% 
80% 
Expon. (20%) 
Expon. (80%) 
200 C 
10,000 yrs 
Source: DTN: LL030606912251.020. 
Figure 92. Time to Form 20% and 80% Grain Boundary Coverage of TCP Phases in Alloy 22 Base 
Metal as a Function of Aging Temperature 
6.6.5.2 Volume-Fraction Measurements in Weld Metal 
6.6.5.2.1 Background 
Gas-tungsten-arc welds, which were made from 0.5-in. thick Alloy 22 base metal in a single 
V-groove configuration using nine passes, were examined using optical microscopy at 
magnifications of 200 and 400 times. These welds were produced and aged at 593C, 649C, 
704C, and 760C for times up to 1,000 hours at Haynes International, Inc. in Kokomo, Indiana 
(Summers et al. 2000 [DIRS 154854]). Volume fraction measurements were also made. The 
amount and size of precipitates in the welds vary with position in the weld. For example, 

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ANL-EBS-MD-000002 REV 02 6-31 September 2004 
relatively few and smaller precipitates tend to be present near weld pass boundaries, while many 
larger precipitates tend to be present at the top of the last weld pass (Figure 42). The 
measurements presented here represent averages over several positions in the weld. These welds 
are also much thinner than those called out in the current waste package design. Welding 
conditions, such as heat input, that may affect the starting weld structure and the subsequent 
precipitation kinetics will be different for thicker welds. Also, several phases are expected in 
Alloy 22 welds; s, , and P have been observed (Cieslak et al. 1986 [DIRS 104966], p. 2,041). 
The growth kinetics for each of these phases may be different. In the base metal, it is likely that 
the amount of s phase precipitating is small at temperatures below about 750C and that  and 
P phases are similar. In the weld, however, the amount of s phase may be quite high due to 
chemical segregation. 
6.6.5.2.2 Tetrahedrally Close-Packed Phase Kinetics in Alloy 22 Welds 
As observed by Cieslak et al. (1986 [DIRS 104966]), TCP phases are present in the interdentritic 
regions of the as-welded structure. After aging, the amount and size of TCP precipitates 
increases with both time and temperature up to 760C. Nucleation of precipitation was also 
observed to form possibly along grain boundaries in some areas of these samples. The volume 
fraction of precipitates is shown as a function of time in Figure 93. Each of the data points 
(Table 4) in Figure 93 represents the average of 20 to 40 measurements. In the as-welded 
condition, there is approximately 0.02 vol. % TCP phase. 
Source: DTN: LL030606912251.020. 
Figure 93. TCP-Phase Precipitation Kinetics in C-22 GTAW Welds as a Function of Temperature 
The volume fraction data of Figure 93 were fit, for each aging temperature with a trend line, 
using Equation 11 (Section 6.6.5.2.1). From these curve fits, the times to give 1% and 5% 
volume fraction were calculated. These times are plotted in Figure 94 as a function of reciprocal 
temperature. The average activation energy calculated from the slopes of these plots 

Aging and Phase Stability of Waste Package Outer Barrier 
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is 241 kJ/mol. Extrapolations of these data indicate that precipitate nucleation and growth in the 
welds will not occur to a significant extent at temperatures below approximately 200C, and also 
significant margin for temperatures below 300C is also evident. 
Source: DTN: LL030606912251.020. 
Figure 94. Time to Form 1 and 5 vol % TCP Phase in C-22 Welds as a Function of Aging Temperature 
6.7 MODEL UNCERTAINTY AND CONFIDENCE 
6.7.1 Model Uncertainty 
6.7.1.1 Experimental Uncertainty 
When experimentally determining the extent of phase precipitation, uncertainty in the 
experimental results is primarily due to measurement uncertainties in the image analysis process. 
In order to determine the area-fraction coverage (%) resulting from phase precipitation, imageanalysis 
software (Image-Pro Plus) is used. Each value representing the area-fraction coverage 
at a specific time and temperature is the result of approximately 40 to 50 measurements. 
Electron microscopy images used in the image analyses are digitized using an 8-bit pixel depth, 
which corresponds to 256 shades of gray per pixel. 
The measurement uncertainty in the area-fraction-coverage values is quantified in the standard 
deviation and 95% confidence interval values for each series measurements at a particular time 
and temperature. The standard deviations and 95% confidence intervals (shown in Table 3 
through Table 4) are computed per ASTM E 562-95, Standard Test Method for Determining 
Volume Fraction by Systematic Manual Point Count ([DIRS 161301], Section 4.1.8). 

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As described in Section 4.1.8, there is more uncertainty (larger standard deviation values) in the 
volume fraction measurements on specimens subjected to lower temperatures or shorter aging 
times, or both. At these temperatures and times, the volume fraction measurements have been 
performed on minimally detectable levels of precipitates (near zero). This uncertainty at nearzero 
levels of precipitation has no impact on the aging and phase stability model because the 
model predicts the extent, not initiation, of phase precipitation as a function of time and 
temperature. The initiation of precipitation (where the uncertainty is large) is of no consequence 
to the aging and phase stability model and has no impact on its results. As shown in 
Section 4.1.8, the uncertainty is considerably reduced in measurements where significant 
amounts (>5%) of precipitation have occurred. 
6.7.1.2 Accuracy of the Thermo-Calc and DICTRA Results 
The analysis of the results on stability and aging is based on calculations made with the Thermo- 
Calc and DICTRA application software packages, respectively. These software codes use 
databases. 
In the case of Thermo-Calc, the original thermo-chemical database that contains information on 
the energetics of all phases made of the ten elements: C, Co, Cr, Fe, Mn, Mo, Ni, Si, V, and W, 
has been extracted from the SSOL database normally called by Thermo-Calc. The database has 
been reevaluated based on experimental data specifically available for the Nibased class of 
alloys. This reevaluation accounted for output information such as assessed-phase diagram, 
measured heat of formation, and transformation for binary and ternary alloys. Once the database 
has been validated, predictions are made on phase-stability information, such as property 
diagrams, isopleths, and ScheilGulliver results on solidification. Hence, the accuracy of the 
output information is mostly based on the machine accuracy of the calculations, once the 
thermochemical database has been validated. 
In the case of DICTRA, two databases are used: the thermo-chemical database used by 
Thermo-Calc and a database that contains information on diffusion coefficients and mobilities. 
The original MOB database that is normally called by DICTRA has been validated with 
experimental information on TTT diagrams available for binary and ternary alloys. Again, once 
validation has been achieved (Section 7), predictions are made for the aging properties of various 
phases exhibited by multicomponent alloys, and the accuracy of the TTT results is mostly based 
on the machine accuracy associated with the numerical resolution of the equations. 
Validation of the databases used in this study is described in detail in Section 7. 

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INTENTIONALLY LEFT BLANK 

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7. VALIDATION 
The goal of this model is to determine whether the single-phase solid solution of Alloy 22 is 
stable under repository conditions, and if not, how fast other phases may precipitate. The aging 
and phase stability model, which is based on fundamental thermodynamic and kinetic concepts 
and principles, is used to provide predictive insight into the long-term metallurgical stability of 
Alloy 22 under relevant repository conditions. 
During the course of developing the aging and phase stability model, the Thermo-calc and 
DICTRA databases were modified to more accurately simulate and analyze the thermodynamic 
and kinetic behavior of Alloy 22. As a result, the first step in model validation was to validate 
the database modifications (in order of increasing complexity) by comparing the calculated phase 
diagrams with those in published literature. These comparisons build confidence in 
demonstrating that the computational model is accurately simulating the phase phenomena 
associated with Alloy 22. Having validated the calculated phase diagrams, it was then prudent to 
proceed with developing the alloy property and TTT diagrams of the aging and phase stability 
model. This validation of the calculated phase diagrams is in addition to the model validation 
activities described in Technical Work Plan for: Regulatory Integration Modeling and Analysis 
of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]). 
The Thermo-Calc results used in analyzing Alloy 22 along with several other Ni-based alloys 
have been validated using comparisons of calculated phase diagrams with published literature for 
(1) the binary sub-systems, (2) the pseudo-binary section Nix(Cr3Mo)1x, and (3) the ternary 
Ni-Cr-Mo alloy (a surrogate for Alloy 22). Agreement of the calculated phase diagrams with 
published literature is excellent and described below. 
In this section, the validation of the calculated phase diagrams is discussed first followed by the 
discussion of the model validation criteria of Technical Work Plan for: Regulatory Integration 
Modeling and Analysis of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]). 
Sensitivity analyses (BSC 2003 [DIRS 168796]) indicate that estimated dose at the regulatory 
compliance point is not sensitive to the aging and phase stability model. As a result, and as 
indicated in Table 2-1 of Technical Work Plan for: Regulatory Integration Modeling and 
Analysis of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]), Level I model 
validation is required for the aging and phase stability model. 

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Confidence-Building During Model Development to Establish Scientific Basis and 
Accuracy for Intended Use 
Section 2.2.1 of Technical Work Plan for: Regulatory Integration Modeling and Analyses of the 
Waste Form and Waste Package (BSC 2004 [DIRS 171583]) specifies several steps for 
confidence building during model development. The model will contain documentation of 
decisions and activities implemented during the model development process to build confidence 
and verify a reasonable, credible, technical approach using scientific and engineering principles. 
The development of the model should be documented in accordance with AP-SIII.10Q 
(Section 5.3.2(b)) requirements. The development of the aging and phase stability model has 
been conducted according to these criteria, as follows: 
(1) Selection of input parameters and/or input data, and a discussion of how the 
selection process builds confidence in the model. (AP-SIII.10Q, 5.3.2(b) (1); 
AP-2.27Q, Attachment 3 Level I (a)). 
The bases for selecting the input data that are used to determine and develop the aging and phase 
stability model are documented in Section 4.1. Model assumptions have been described in 
Section 5. Detailed discussion about the computational model concepts can be found in 
Section 6.5. Thus, this requirement is satisfied. 
(2) Description of calibration activities, and/or initial boundary condition runs, 
and/or run convergences, simulation conditions set up to span the range of 
intended use and avoid inconsistent outputs, and a discussion of how the activity 
or activities build confidence in the model. Inclusion of a discussion of impacts of 
any non-convergence runs. (AP-SIII.10Q, 5.3.2(b)(2); AP-2.27Q, Attachment 3 
Level I (e)). 
Model formulations for the aging and phase stability model are discussed in Sections 6.5. 
Kinetic and thermodynamic modeling have been combined and applied to the study of diffusioncontrolled 
transformations with the use of the DICTRA application linked with Thermo-Calc. 
Simulations have been performed and validated on three alloy systems, in order of increasing 
complexity: (1) a binary NiCr alloy, (2) a pseudo-binary NiX(Cr3Mo)1X alloy, and (3) a ternary 
NiCrMo alloy that can be considered as a surrogate for Alloy 22 (Sections 6.6.4, 7.1, 7.2, 7.3, 
and 7.4). Thus, this requirement is also satisfied. 
(3) Discussion of the impacts of uncertainties to the model results including how 
the model results represent the range of possible outcomes consistent with 
important uncertainties. (AP-SIII.10Q, 5.3.2(b)(3); AP-2.27Q, Attachment 3 
Level 1 (d) and (f)). 
Accuracy of the Thermo-calc and DICTRA results and the uncertainties associated with the 
experimental data supporting the computational model are described in Section 6.7. Thus, this 
requirement is satisfied. 

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(4) Formulation of defensible assumptions and simplifications. (AP-2.27Q, 
Attachment 3 Level I (b)). 
Discussion of assumptions and simplifications and their rationale are provided in Section 5. 
Thus, this requirement is satisfied. 
(5) Consistency with physical principles, such as conservation of mass, energy, 
and momentum. (AP-2.27Q, Attachment 3 Level I (c)) 
The computational model employs Thermo-Calc and DICTRA and is based on the so-called 
CALPHAD (CALculation of PhAse Diagrams) approach. This approach involves the coupling 
of phase diagrams calculations for multicomponent alloy systems with other forms of thermochemical 
inputs to determine phase formation, proportions, and transformations (Section 6.5). 
Thus, the aging and phase stability model is based on fundamental thermodynamic and kinetic 
concepts and principles and, thus this requirement is satisfied. 
Confidence-Building After Model Development to Support the Scientific Basis of the 
ModelThe specific validation criteria (from AP-SIII.10Q) to be applied to the aging and phase 
stability model after model development are: 
(1) Corroboration of model results with data acquired from the laboratory, field 
experiments, analog studies, or other relevant observations, not previously used 
to develop or calibrate the model (AP-SIII.10Q, Section 5.3.2). 
Confidence in the accuracy of the models is addressed by evaluating the consistency of the 
models with data published in refereed journals or industrial literature and data from laboratory 
tests not used to develop the models (Sections 7.1 through 7.4). In Section 7.4, confidence in the 
developed computational aging and phase stability model is established by comparing the model 
to available project data that were not used in the models development, and this comparison 
showed that the model is conservative. Thus, this requirement is satisfied. 
(2) Corroboration with information published in refereed journals or literature 
(AP-SIII.10Q, Section 5.3.2). 
Confidence in the accuracy of the models is addressed by evaluating the consistency of the 
models with data published in refereed journals (Sections 7.1 through 7.3). In these sections, 
published data is used to build confidence in the developed computational aging and phase 
stability model by comparing these data with the results from three alloy systems, in order of 
increasing complexity: (1) a binary NiCr alloy, (2) a pseudo-binary NiX(Cr3Mo)1X alloy, and 
(3) a ternary NiCrMo alloy that can be considered as a surrogate for Alloy 22. Thus, this 
requirement is satisfied. 

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The specific validation criteria applicable to the aging and phase stability model, as described in 
the technical work plan (BSC 2004 [DIRS 171583], Table 2-1), are: 
(VA 1) Do comparisons of Topologically Close-Pack Phases (TCP) and Longrange 
ordering (LRO) formations in base metal from THERMOCALC / DICTRA 
agree with experimental data on base metal? 
(VA 3) Do experimental data on TCP formations on base metal grain boundaries 
and TCP and LRO formations in weld metal corroborate with data in peerreviewed 
literature or fundamental metallurgical phenomena? 
(VA 3) Do comparisons of volume fraction measurements agree with peerreviewed 
published literature (where applicable) and /or fundamental 
metallurgical phenomena? 
Corroborating data must match qualitatively. 
Section 7.5 describes in detail the application of these validation activities to the aging and phase 
stability model. 
7.1 VALIDATION OF THE THERMO-CALC RESULTS FOR THE BINARY SUBSYSTEMS 
The calculated phase diagrams, as obtained from Thermo-Calc for CrNi, MoNi, CrMo, 
CrW, MoW, and NiW are presented in Figure 95 together with the experimentally 
determined phase diagrams extracted from Binary Alloy Phase Diagrams (Massalski 1990 
[DIRS 118757]). These results indicate that the thermo-chemical database is able to account for 
the stability of most phases encountered experimentally in the composition and temperature 
domains in the NiMo binary alloy, namely Ni4Mo, Ni3Mo, and NiMo, and in the NiW binary 
alloy, namely Ni4W, NiW, and NiW2. The results also account for the phase separation tendency 
in the body centered cubic (bcc) solid phase that is observed in the case of CrMo and CrW. 
The binary Mo-W alloy displays an ideal solid solution based on the bcc phase with no particular 
tendency toward compound formation or phase separation. Also, in the case of the binary NiCr 
alloy, the ordered phase that is experimentally observed at low temperatures around the 
stoichiometry Ni2Cr (referred to as oP6 or C11b) is not accounted for with the initial SSOL 
database. 

Aging and Phase Stability of Waste Package Outer Barrier 
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NiCr 
NiMo 
CrMo 
CrW 

Aging and Phase Stability of Waste Package Outer Barrier 
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NiW 
Mo-W 
Source: (left) Massalski et al. [DIRS 118757]; (right) DTN: LL030106412251.014. 
Figure 95. Comparison Between Experimentally Determined (Left) and Calculated (Right) Phase 
Diagrams of NiCr, NiMo, NiW, CrMo, CrW, and MoW alloys, as Obtained with 
Thermo-Calc 
7.1.1 Modeling of the Ordered Phase oP6 
To introduce the relevant data that define the Gibbs energy for the ordered phase C11b (or oP6) 
made of Ni, Cr, Mo, and W, the following information was used. First, the experimental work 
performed by Hirabayashi et al. (1969 [DIRS 161452]) suggests a heat of formation for the 
Ni2Cr ordered phase of approximately 4,200 J/g.at (or approximately 1,000 cal/g.at). Second, 
the experimental work by Karmazin et al. (1994 [DIRS 161444]), carried out for the oP6-ordered 
phase in Ni-rich NiCrMo alloys, indicates that Mo can be located on two sublattices. Third, 
ab initio electronic-structure calculations based on the tight-binding linear muffin-tin orbital 
(TB-LMTO) method (Turek et al. 2000 [DIRS 163109]) allows the estimation of the heat of 
formation of the oP6-ordered phase for Ni2Cr, Ni2Mo, and Ni2W. The results of total energyversus-
lattice parameter for the ordered phase based on the fcc lattice are plotted in Figure 96 for 
the three compounds. 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL030106412251.014. 
NOTE: The zero of energy is taken as the concentration weighted average of the total energies of fcc Ni and bcc 
Cr (or Mo, W). 
Figure 96 Total Energy (In kj/mol) Versus Normalized Lattice Parameter (i.e., a/aeq, Where a is the 
Lattice Parameter and aeq is the Equilibrium Lattice Parameter) for the Three Ordered 
Compounds Ni2Cr, Ni2Mo, and Ni2W Of Ni2Cr-Type (C11b or oP6) 
Hence, in the following, the ordered phase is treated within a two-sublattice model 
(Section 6.5.3) with Cr, Mo, and W on one sublattice and Mo and Ni on the other sublattice. The 
compound phase parameters (computed with temperature T in K, and the energies in J/g.at) are 
defined as follows (note that the parameters not included in the following are set to zero): 
fcc-oP6 2-sublattice model (Cr,Mo,W)1(Mo,Ni).2, i.e., with p = 1 and q =2 
oP6 fcc
Mo : Cr 
- .G = oP6 fcc 
Mo : Mo
- .G = oP6 fcc
Mo : W 
- .G = 6000 oP6 fcc
Ni : Cr 
- .G = 7095  5.6*T 
oP6 fcc 
Ni : Mo
- .G = +1,000 oP6 fcc
Ni : W 
- .G = 10,000 (Eq. 11) 
oP6 fcc 
Ni Mo, : Cr 
0 - L = 80,000 oP6 fcc 
Ni : Mo Cr, 
0 - L = 11,000 oP6 fcc 
Ni W, : Cr 
0 - L = 55,000 oP6 fcc 
Ni : W Cr, 
0 - L = 8,000 
Based on the above discussion, these parameters were incorporated into the Thermo-Calc 
database to more properly model the oP6-ordered phase (Turchi 2003 [DIRS 162974]). 
To adjust the experimental information on Ni2Cr-ordered phase with already available 
thermodynamic data in the SSOL database, the heat of formation of Ni2Cr became 7,095 J/mole 
(instead of 4,187 J/mol). The data for Mo-Ni and W-Ni account for the ab initio results that 
indicate that Ni2Mo is barely stable, whereas Ni2W is unstable (leading to a positive heat of 
formation of 10,000 J/mole). Finally the description of particular species on both sublattices is 
contained in the two RedlichKister parameters oP6 fcc 0 - L (Redlich et al. 1948 [DIRS 161464]). 
Their values have been adjusted to allow Mo to be located on the two sublattices, to spread the 
domain of stability of the ordered phase in accordance with Karmazin et al.s (1994 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-8 September 2004 
[DIRS 161444]) results and, at the same time, to account for the effect of Mo addition on the 
orderdisorder transition temperature (Karmazin et al. 1994 [DIRS 161444]). Although Ni2Mo 
is barely stable, the magnitude of the critical orderdisorder temperature for the oP6-ordered 
phase goes through a maximum as a function of Mo composition. This nonlinear effect of Mo is 
captured in the energetic description of the ordered compound. 
The results of this reassessment are displayed in Figure 97 and are in agreement with the 
accepted phase diagram of NiCr. 
NiCr 
Source: DTN: LL030106412251.014. 
NOTE: The domain of stability of the ordered phase of Ni2Cr-type (oP6 or C11b). 
Figure 97. Comparison of the Reference NiCr-Phase Diagram (Left) with the Calculated Ni-Cr-Phase 
Diagram as Obtained with the Ordered Phase Modeled (Right) 
7.2 VALIDATION OF THE THERMO-CALC RESULTS FOR THE PSEUDO-BINARY 
Nix(Cr3Mo)1x ALLOY 
To further validate the database, the experimental determination of the phase boundaries in the 
terminal Ni-rich .-solid solution in the pseudo-binary section Nix(Cr3Mo)1x, (with 
cCr+Mo=cCr+cMo varying from 13.5 to 44 at %) (Karmazin et al. 1994 [DIRS 161444]) were 
considered. It was shown experimentally that the boundary of the terminal .-solid solution was 
increasing with cCr+Mo as indicated in Figure 98a. Calculations were performed with the 
reassessed database for the same section of the ternary phase diagram with all the phases 
considered except the P phase. The calculated phase diagram, shown in Figure 98b, compares 
favorably with the experimental counterpart, displayed in Figure 98a, as far as the boundary of 
the .-solid solution (indicated by a thick black line) is concerned. A two-phase region (fcc + s) 
is also predicted in the temperature range 620C to 1,370C at lower Ni content. However, since 
the experimental study did not include the structural characterization of these phases at high 
temperature in this stability region, the predicted two-phase region could not be confirmed. In 
retrospect, the suspension of the P phase during the calculation of the phase diagram is 
equivalent to modeling that the kinetics of P-phase formation is much slower than the phase 
diagram associated with the formation of the s phase. This approach has been described in 
Section 6.6.1 where the property diagram of Alloy 22 showed that that the stability of the 
s phase can be extended at low temperatures when the P phase is suspended. This is a result that 
is confirmed experimentally. 

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(a) (b) 
(c) 
Source: (a) DTN: LL030106412251.014 (b), (c) Karmarzin et al. 1994 [DIRS 161444]. 
NOTE: The evolution of dT given by the difference between the lattice parameter measured at temperature T and 
the a1100, its initial value obtained after quenching samples from 1,100C is displayed in (c) for several 
isothermal anneals as a function of time. 
Figure 98. Comparison Between the (a) Calculated (with Thermo-Calc) and (b) the Experimental 
Phase Diagrams of the Pseudo-Binary Alloy Ni-(Cr0.75Mo0.25) 

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7.3 VALIDATION OF THE THERMO-CALC RESULTS FOR THE TERNARY NiCr 
Mo ALLOY 
Isothermal sections of the NiCrMo phase diagram were calculated and compared with the 
experimental results (Gdowski 1991 [DIRS 100859]; Jena et al. 1989 [DIRS 161441]; 
Rideout et al. 1951 [DIRS 161445]; Bloom et al. 1954 [DIRS 161463]; Raghavan et al. 1984 
[DIRS 154707]; Cieslak et al. [DIRS 104966]). For example, the results reported by 
Bloom et al. [DIRS 161463] are shown in Figure 99. The Ni-Cr-Mo system in the entire 
composition range has been thoroughly reviewed by Jena et al. (1989 [DIRS 161441]) (see also 
Gdowski 1991 [DIRS 100859]). Here, all the alloys of interest (Table 8) are located in the 
high-Ni rich portion of the phase diagram (Ni content above 50 wt %), and more specific studies 
have been reported in this limited region of the phase diagram (Rideout et al. 1951 
[DIRS 161445], Bloom et al. 1954 [DIRS 161463], Raghavan et al. 1984 [DIRS 154707]). In 
this region, the single fcc (.)-phase is stable at high temperatures and the domain of . stability 
diminishes toward the Ni-rich corner with decreasing temperature, as illustrated in Figure 101. 
This study confirms the fact that at equilibrium and at low temperature, all the alloys indicated in 
Table 8 should display a multiphase field that includes the fcc structure and one or two complex 
phases, such as s, , or P (Frank et al. 1958 [DIRS 161437], Frank and Kasper 1959 
[DIRS 161438]; Shoemaker and Shoemaker 1988 [DIRS 154989]). In Figure 99, the 
thermodynamic calculations performed at 1,523 K (1,250C) reproduce fairly well the lenticular 
shape of the domain of stability of the s phase. In the following, since the TCP, P, and  phases 
are closely related, a distinction will not be made between them as far as the energetics and the 
kinetics of formation are concerned. The results of the calculations also confirm that the fccphase 
field is shrinking in the Ni-rich corner of the phase diagram as the temperature is lowered, 
as shown in Figure 100. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-11 September 2004 
Source: DTN: LL030106412251.014. 
NOTE: The bottom right figure shows the experimentally assessed isothermal section of the ternary-phase 
diagram from Bloom et al. 1954 [DIRS 161463] at 1,523 K. 
Figure 99. Calculated Isothermal Sections of the NiCrMo Phase Diagram at 1,123 K, 1,323 K, and 
1,523 K 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-12 September 2004 
Source: DTN: LL030106412251.014. 
Figure 100. Calculated Isothermal Sections of the NiCrMo Phase Diagram at 573 K, 773 K, 893 K, 
and 973 K 
As commercial alloys are not pure ternary alloys, Cr, Mo, and Ni equivalents have been 
proposed by correlating the behavior of minor elements (e.g., Co, Fe, Ti, and W) with the major 
elements (Cr, Mo, and Ni) in the formation of TCP precipitates. Cieslak et al. (1986 
[DIRS 104966]) proposed the following relations applicable to Alloys 22, C4, and C-276: 
Moeq = wt % Mo + wt % W 
Creq = wt % Cr (Eq. 13) 
Nieq = (balance; in wt %) 
However, the property diagrams of these commercial alloys bear very little resemblance to those 
generated for the alloys at their equivalent compositions. Hence, extreme caution must be taken 
when making arguments based on Cr, Mo, and Ni equivalents. As shown previously, for 
example, W and Mo have a direct influence, qualitatively and quantitatively, on the stability of 
the oP6-ordered phase (Section 7.1). 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-13 September 2004 
By limiting the analysis to the fcc matrix and the Ni2Cr-type (or oP6) ordered phase (i.e., with 
all other phases suspended), the isothermal sections at 620C, 600C, 500C, and 300C of the 
NiCrMo phase diagram were re-calculated. The results presented in Figure 102 show the 
domain of stability of the oP6 and its extension in the Ni-rich corner of the phase diagram when 
temperature decreases. The detailed location of the oP6-ordered phase in the ternary Ni-Cr-Mo 
alloy in the phase diagram and how Mo affects the stability of the ordered phase and the location 
of the critical order-disorder transition temperature are illustrated in Figure 103 for fixed Ni mole 
fractions of 0.625, 0.645, and 0.665. As discussed before, the addition of Mo does not have a 
simple gradual effect on the stability of the oP6-ordered phase. For example, in the case of a 
fixed mole fraction of Ni equal to 0.645, there is a gradual increase in the stability of the ordered 
phase by substituting Cr for Mo up to about 0.20-mole fraction of Cr before destabilization of 
oP6 phase at higher substitution of Cr for Mo, as shown in Figure 103. This study confirms the 
fact that at equilibrium and at low temperature, all the alloys indicated in Table 8 should display 
a multiphase field that includes the fcc structure and one or two complex phases, such as s, , 
or P. 
Source: DTN: LL030106412251.014. 
Figure 101. Calculated fcc (or .) Domain of Stability of the Ternary Ni-Cr-Mo Phase Diagram as a 
Function of Temperature from 1,250C to 300C 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL030106412251.014. 
NOTE: Only the fcc (or .) matrix and the oP6-ordered phase are considered for this set of calculations. 
Figure 102. Calculated Isothermal Sections of the Ternary NiCrMo Phase Diagram at 893 K, 873 K, 
773 K, and 573 K 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-15 September 2004 
Source: DTN: LL030106412251.014. 
NOTE: Only the fcc (or .) matrix and the oP6-ordered phase are considered for this set of calculations. 
Figure 103. Calculated Isopleths of the Ternary NiCrMo Alloy at Fixed Mole Fraction of Ni of 0.625, 
0.645, and 0.665 
7.4 VALIDATION OF THE TREATMENT OF MO AND W IN THE TERNARY 
NiCrMo ALLOY 
In the course analyzing the ternary NiCrMo alloy as surrogate for Alloy 22, published 
experimental data for NiCr and NiCrMo systems have been considered for characterizing the 
oP6-ordered phase of Ni2Cr-type. Since Mo and W play a role in the stability of this ordered 
phase, it was necessary to include their effects in the alloy energetics. 
The ab initio results for the oP6 forms of Ni2Cr, Ni2Mo, and Ni2W, and the fcc phases were 
considered to evaluate the effect of Mo and W additions, and to compare the calculated results 
with the experimental findings reported in the literature. Ab initio results for the heat of 
formation of Ni2Cr, Ni2Mo, and Ni2W are 10,485, +1,014, and 10,074 J/mol, respectively 
(Section 7.1.1, Figure 96). These values were incorporated into the database as 7,095, +1,000, 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-16 September 2004 
and 10,000 respectively. The database value for Ni2Cr was adjusted from experimental results 
(Hirabayashi et al. [DIRS 161452]) and phase-diagram calculations while the remaining values 
for Ni2Mo (+1,000) and Ni2W (+10,000) are rounded ab initio results. The most complete 
data for the effect of Mo on the relative stability of oP6 and fcc in Ni-Cr-Mo alloys 
is due to Karmazin et al. [DIRS 154881]. This experimental work indicates that a Ni25 at % 
Cr8.33 at % Mo alloy has a maximum critical orderdisorder temperature for the oP6 to fcc 
transition on heating of about 670C, as compared with a maximum transition temperature of 
570C for a Ni33.3 at % Cr alloy. Karmazin (1982 [DIRS 154881]) mentions that Mo can be 
located on both sublattices that describe the oP6 phase. The role of W on the stability of the oP6 
phase is not experimentally documented. Hence, as for Mo, W is allowed to occupy both 
sublattices. The interaction parameters are smaller than those associated with Mo, since for 
Ni2W, the instability is more significant than for Ni2Mo. 
Ab initio calculations have shown that MoW behaves like an ideal solution, because the heat of 
formation of the alloy in the entire range of composition is practically zero. This result indicates 
that Mo and W, which belong to the same VIb column of the transition metals, have very similar 
electronic structure properties. This does not preclude any difference in alloying effect, as 
shown in Figure 96, when Mo and W are mixed with other elements such as Ni, due to 
differences in the manner which atomic orbitals between various elements hybridize. 
To account for these observations, the following interaction parameters have been selected: 
oP6 fcc 
Ni :Mo, Cr 
0 - L = 80,000 oP6 fcc 
Ni : Mo Cr, 
0 - L = 11,000 
oP6 fcc 
Ni W, : Cr 
0 - L = 55,000 oP6 fcc 
Ni : W Cr, 
0 - L = 8,000 
Based on the above discussion, these interaction parameters have been included in the Thermo- 
Calc database to model the Mo and W behavior in the ternary Ni-Cr-Mo alloy system 
(Turchi 2003 [DIRS 162974]). 
With this new description, the oP6fcc equilibrium shown in Figure 104a and Figure 104c for 
the NiCrMo and NiCrW systems, respectively, is close to the composition of Alloy 22. 
These results suggest that in NiCrMo, the 21.1 wt % Cr13.5 wt % Mo composition lies very 
close to Alloy 22 stoichiometry, and little fcc phase is present when this alloy is cooled 
below 635C, see Figure 104b. W has a smaller stabilizing effect on oP6 than does Mo, as 
shown in Figure 104c. Measurements of the kinetics of ordering (oP6) formation 
conducted at Lawrence Livermore National Laboratory (Shen 1999 [DIRS 161800]) in Alloy 22 
(Ni21.1 wt % Cr13.5 wt % Mo3 wt % W) suggested that the maximum temperature for the 
oP6/fcc transition is above 593C, or some 53C higher than in the Ni-Cr case. As W has mostly 
a destabilizing effect on the formation of the oP6-ordered phase, several tests performed to 
account for this fact have shown that to model Alloy 22 with a Ni-Cr-Mo surrogate alloy, 
2.0 wt % Mo for each 1.0 wt % W in the fcc phase provides an acceptable representation of the 
oP6fcc phase region. In other words, Alloy 22 with 21.1 wt % Cr13.5 wt % Mo3 wt % W 
can be replaced by Ni21.1 wt % Cr7.5 wt % Mo. This equivalent composition 
leads to much more fcc phase in the temperature range of precipitation than with the 21.1 wt % 
Cr13.5 wt % Mo composition, as can be concluded from the comparison between Figure 104d 
(below about 600C) and Figure 104b. 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL030106412251.014. 
NOTE: The vertical lines in (a) and (c) locate the composition of Ni21.1 Cr13.5 Mo and Ni21.1 Cr1.8 W (in 
wt %), respectively. Property diagrams of Ni24.5 Cr8.5 Mo (in at %) or Ni21.1 Cr13.5 Mo (in wt %) 
(b), and Ni21.1 Cr7.5 Mo (in wt %) (d). 
Figure 104. Phase Diagrams of NiCrX, with cCr+cX=0.33 Being Fixed, Where X=Mo (a), X=W (c) 
To further validate this approach accounting for the role of Mo and W, the 
experimental results reported by Shen (2000 [DIRS 161801]) are considered. As an 
example, consider a sample of Alloy 22 with the following composition: 21.1 Cr13.5 Mo4.7 
Fe2.9 W1.74 C0.21 Mn0.12 V0.023 Si0.003 C (in wt %) annealed for 16,000 hours at 
704C. At this annealing temperature, substantial precipitation occurs at grain boundaries and in 
the fcc-based matrix. These precipitates correspond to the P (and possibly ) phase, and are 
identifiable by their platelet shape (Figure 105a). At this annealing temperature of 704C, and 
according to the property diagram presented in Figure 106a, the most likely phase to form is 
indeed the P phase with a phase fraction of about 20%. Energy dispersive x-ray (EDS) analysis 
has been performed using a Philips CM300 equipped with an EDS detector across the TCP 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-18 September 2004 
precipitate along the line indicated in Figure 105a to determine the evolution of elemental weight 
fractions as functions of distance. As shown in Figure 105b, the alloy composition varies 
substantially when crossing the precipitate. As expected the P-phase formation is accompanied 
by a noticeable decrease in Ni content compensated by an increase in Mo content, and to some 
extent a decrease in Cr and Fe, and an increase in W. Quantitatively, with the reference set to the 
composition of the base alloy mentioned above, the composition in Ni, Cr, Mo, Fe, and W 
becomes in the P-phase precipitate 30, 18, 45, 3, and 3 (in wt %), respectively. Calculations 
have been performed to calculate the property diagram of Alloy 22 at the composition mentioned 
above, and the weight fractions per element in the fcc matrix and the P phase have been 
computed. The results are summarized in Figure 106. At 704C, the temperature at which the 
isothermal annealing has been performed, the fcc phase qualitatively retains its starting alloy 
composition. On the other hand, in the P phase, the composition of each major constituent Ni, 
Cr, and Mo is 36, 24, and 39 (in wt %), respectively. These results are in fairly good agreement 
with the experimental findings, recognizing that the experiments are conducted on samples that 
may not have reached their full thermodynamic equilibrium, which is the basis for the 
calculations. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-19 September 2004 
Source: DTN: LL030106412251.014; Shen 2000 [DIRS 161801]. 
Figure 105. (a) Micrograph of Platelet P-Phase Precipitate in an fcc Matrix, and Location of the (Red) 
Line Profile Along Which the Energy Dispersive X-ray (EDS) Analysis is Performed. (b) 
Variation of the Weight Fraction per Element Along the Line Profile, as Obtained from EDX 
Spectroscopy Analysis for Alloy 22 Annealed at 704C for 16,000 hours. 
(b) 
(a)

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-20 September 2004 
Source: DTN: LL030106412251.014. 
NOTE: The vertical line indicates the temperature at which the alloy has been annealed. 
Figure 106. (a) Property Diagram of Alloy 22. Weight Fraction of Ni (Red), Cr (Blue), Mo (Green), 
W (Brown), and Fe (Black), Versus Temperature in the fcc Matrix (b), and the P Phase (c) 
for Alloy 22 
7.5 MODEL CONFIDENCE: NATURAL ANALOGUES 
Awaruite is a naturally occurring, ordered ironnickel metallic mineral with an approximate 
stoichiometry of Ni3Fe. It was first discovered in Awarua, New Zealand, but has subsequently 
been found at various locations around the world (Krishnarao 1964 [DIRS 154746], p. 443). 
Josephinite, a rock found in Josephine County, Oregon, contains grains of awaruite that are 
larger than other sources of awaruite. Josephinite also has, in some instances, a unique mixture 
of minerals that has been tied to changes in the local environment and higher temperatures 
associated with hornblende diorite dikes from igneous intrusions (Dick 1974 [DIRS 154749], 
p. 297; Gpel et al. 1990 [DIRS 154750], p. 26). The age of these dike intrusions has been 
measured using KAr dating to be approximately 150 to 155 million years (Dick 1974 
[DIRS 154749], p. 292). Other nearby rocks also associated with the formation of josephinite 
have been dated, using Pb isotopes, at 159  8 million years (Gpel et al. 1990 [DIRS 154750], 
p. 24). Thus, the age of josephinite is on the order of 150 million years. 
Some samples of josephinite contain taenite (the high-temperature, disordered, FCC NiFe 
metallic phase) as well as awaruite. The composition and amount of each of these phases in the 
two-phase mixture have been fit to the FeNi phase diagram, showing that these phases formed 
in the temperature range of 460C down to about 400C (Botto and Morrison 1976 
[DIRS 154716]). The fact that the composition and amount of these phases fit the phase diagram 
at the higher temperatures indicates that no changes have occurred at lower temperatures. 
Taenite is not stable below about 350C; aFe and awaruite are the stable phases at ambient 
temperatures. The fact that taenite, not aFe, is present in josephinite also indicates that no 
changes have occurred in the 150 million years since these samples formed. 
Out of necessity, phase stability is studied at temperatures greater than those expected in the 
proposed repository so that the rate at which phase changes occur can be measured. These rates 
are measured as a function of temperature, and the functional relationship is extrapolated to the 
lower temperatures in the proposed repository. The stability of the metallic structures in 
josephinite over millions of years suggests that no low-temperature mechanism with rates 
significantly greater than predicted exists. Thus, this provides confidence in the implicit 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 7-21 September 2004 
assumption that the high-temperature mechanisms used to extrapolate kinetics are the same as 
the low-temperature mechanisms that will really be active under repository conditions. 
7.6 DISCUSSION OF MODEL VALIDATION ACTIVITIES 
In this section, each of the model validation criteria described in Technical Work Plan for: 
Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package (BSC 
2004 [DIRS 171583]) are discussed. 
Criterion One 
Do comparisons of Topologically Close-Pack Phases (TCP) and Long-range 
ordering (LRO) formations in base metal from THERMOCALC/ DICTRA agree 
with experimental data on base metal? 
Using the TCP precipitation area-fraction measurements for base metal presented in Table 9, 
Figure 107 summarizes these measurements as a function of time and temperature. A trend line 
is included for the results at 760C, where more than two measurements were made. The trends 
of the results shown in Figure 107 are consistent with SEM observations and the TTT diagram of 
Figure 89. TCP phases are seen to readily form at higher temperatures (760C to 800C) in less 
than 1,000 hours. In general, as the temperature is decreased, the onset of TCP phase 
precipitation is delayed, and it also appears that the slopes of trend lines at lower temperatures 
may become shallower, indicating a slower rate of phase precipitation. 
Table 9. Bulk Precipitation Area-Fraction Measurements (% Transformation) 
Temperature 
(C) 
Time 
(hr) 
Percent 
Transformation 
Standard 
Deviation 
95% 
Confidence Interval 
649 16,000 2.50 1.60 0.64 
650 600 0.00 0.00 N/A 
700 10,073 8.10 1.40 0.64 
704 16,000 19.00 3.60 1.65 
750 10,076 17.90 1.80 0.93 
760 16,000 22.50 2.90 1.50 
760 2,000 10.10 1.10 0.53 
760 1,000 6.30 1.20 0.57 
760 119 0.73 0.28 0.11 
800 1,002 12.70 0.86 0.44 
800 100 1.50 0.47 0.19 
Source: DTN: LL030103812251.008 [DIRS 162011]. 
NOTE: Confidence Interval values rounded to two decimal places. 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL030606912251.020. 
Figure 107. TCP-Phase Precipitation in Alloy 22 Base Metal as a Function of Time and Temperature 
The computational phase kinetics results (from DICTRA) for the ternary NiCrMo alloy (a 
surrogate for Alloy 22) were compared with volume-fraction measurements on Alloy 22 base 
metal at temperatures of approximately 700C and 750C (Figure 108 and Figure 109). The 
computation phase kinetics results are used to construct the computational TTT diagrams for a 
particular phase (Section 6.6.4). The comparison is not entirely consistent because (1) the 
volume-fraction measurements do not distinguish among the possible TCP phases (P, , and s) 
that have formed, and (2) the DICTRA results only display one type of phase fraction at a time. 
As a result, Figure 108 and Figure 109 compare the P phase formation results from DICTRA 
with the TCP volume-fraction measurements, as the P phase is the most likely to form at these 
temperatures and times. At high temperatures and long aging times, more phases in addition to 
the P phase may form, which would increase ambiguity in the comparison. As a result, in order 
to make the comparisons as consistent as possible, the comparisons presented in Figure 108 and 
Figure 109 were only able to include a few volume-fraction measurements from Table 9. For 
this comparison, the few volume-fraction measurements shown in these plots were deemed to 
most likely contain primarily P phase at the times and temperature shown. 
In both comparisons, the agreement between the computational kinetics results and the volumefraction 
measurements is reasonable. The comparison shows that the computational results are 
conservative compared to the measured data, as the measured data points always lie to the right 
(increasing time) of the DICTRA results. As a result, the computational model predicts slightly 
earlier phase formation that what is measured at a given temperature. This conservativeness is 
expected because the DICTRA results are based on a ternary NiCrMo alloy, Ni21.1Cr 
13.5Mo (in wt %), which is a surrogate for Alloy 22, and the actual composition of Alloy 22 
contains less Ni (the balance of Ni will be less due to more elements specified in the actual 
Alloy 22 chemical composition). 

Aging and Phase Stability of Waste Package Outer Barrier 
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Source: DTN: LL030606912251.020. 
Figure 108. Comparison of Phase Formation at 700C for DICTRA Computational Results (P Phase) 
and Measured Data (TCP Phase) on Alloy 22 Base Metal 
Source: DTN: LL030606912251.020. 
NOTE: Measured Data was Obtained at 760C. 
Figure 109. Comparison of Phase Formation at Approximately 750C for DICTRA Computational 
Results (P phase) and Measured Data (TCP Phase) on Alloy 22 Base Metal 

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The kinetics of LRO are treated in a manner similar to that discussed for TCP phase 
precipitation. However, very little kinetic data exists for LRO in Alloy 22. A very fine 
dispersion of ordered domains was seen after aging for 30,000 and 40,000 hours at 427C in 
Alloy 22 base metal (Figure 48 through Figure 50) and in a weld similarly aged (Figure 51 
through Figure 56). The ordering in these cases is so fine that it would be difficult to measure 
the volume fraction of the ordered domains. LRO was also observed in Alloy 22 base metal 
aged at 593C for 16,000 hours and at 538C and 593C for 1,000 hours. The volume fraction of 
ordered domains has not been measured in these samples. Alloy 22 base metal samples aged for 
40,000 hours at 260C and 343C and for 1,000 hours at 482C were also examined in TEM, but 
no LRO was observed. 
Unlike TCP-phase precipitates, LRO results in very small and finely dispersed precipitates. As a 
result, SEM image analysis is not well suited to determine the extent of LRO kinetics. However, 
due to the uniformly and finely dispersed nature of LRO, microhardness measurements are 
indicative of LRO, because analogous to precipitation age-hardened alloys, hardness increases 
with the amount of precipitation (Reed-Hill 1973 [DIRS 162684]). Table 10 summarizes the 
microhardness (Hv) measurements made on Alloy 22 as a function of time and temperature. 
Table 10. Microhardness (Hv) Measurements in Aged Base Metal 
Temperature 
(C) 
Time 
(hr) 
Microhardness 
(Hv) 
600 1 220 
600 4 218 
600 10 223 
600 40 223 
600 100 221 
600 200 223 
600 400 219 
600 600 216 
600 800 222 
593 10 204 
593 30 218 
593 92 215 
593 100 207 
593 300 218 
593 600 218 
593 1,000 298 
593 1,011 214 
593 16,000 265 
550 100 237 
550 300 274 
550 600 301 
550 1,000 329 
550 2,000 328 
550 4,500 346 

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Table 10. Microhardness (Hv) Measurements in Aged Base Metal (Continued) 
Temperature 
(C) 
Time 
(hr) 
Microhardness 
(Hv) 
550 6,000 364 
550 8,000 359 
538 10 210 
538 100 218 
538 1,000 300 
500 100 212 
500 300 227 
500 600 252 
500 1,000 277 
500 2,000 298 
500 4,500 307 
500 6,000 368 
500 8,000 308 
482 10 210 
482 100 204 
482 1,000 237 
427 10,000 218 
427 20,000 223 
427 30,000 227 
427 40,000 245 
400 1,000 215 
400 2,000 218 
400 4,500 210 
400 6,000 211 
400 8,000 213 
343 30,000 261 
343 40,000 212 
260 10,000 216 
260 30,000 216 
260 40,000 210 
As-received 217 
Source: DTN: LL030607112251.021 
[DIRS 163927]. 
These microhardness results are graphically presented in Figure 110. Trend lines have been 
included for the results at 500C and 550C. Some of the temperature values shown in Table 10 
have been rounded to one or two significant figures (e.g., 593C  600C) when plotted in 
Figure 110. The microhardness of as-received material was 217 Hv. 
The microhardness measurements indicate that LRO has occurred at temperatures in 
approximately the 500C to 550C range up to 40,000 hours. In addition, for results up to 
40,000 hours, no LRO is evident for temperatures below 400C, and little LRO is seen at 

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temperatures around 600C. The observation of very little LRO near 600C corroborates well 
with the critical order-disorder temperature of about 596C of the computational model 
(Section 6.6.4.3). These microhardness measurements add confidence to the observation from 
the computational TTT diagrams that formation of the oP6-ordered phase from the fcc-solid 
solution will not be a concern for conditions of less than 300C for a period of 500 years 
followed by temperatures less than 200C for a period of 9,500 years conditions that bound the 
repository time-temperature profiles (BSC 2004 [DIRS 169565], Figure 6.3-57). 
y = 159.55x0.0934 
R2 = 0.9292 
y = 150.64x0.0839 
R2 = 0.7846 
0 
50 
100 
150 
200 
250 
300 
350 
400 
1 10 100 1,000 10,000 100,000 
Time (hr) 
Micro-Hardness (Hv) 
600C 
550C 
500C 
400C 
343C 
260C 
Power (550C) 
Power (500C) 
NOTE: Microhardness values are indicative of LRO. Microhardness of as-received base metal is 217 Hv. 
Figure 110. Microhardness (Hv) Measurements on Aged Alloy 22 Base Metal as a Function of Time 
and Temperature. 
For LRO in base metal, the TTT diagram for the oP6 phase of the ternary NiCrMo alloy (a 
surrogate for Alloy 22) was presented in Section 6.6.4.2. In addition, microhardness 
measurements were used (Figure 110) to provide insight into the extent of LRO at several times 
and temperatures. In comparing the measurements indicative of LRO and the calculated TTT 
diagram, it was shown (Section 6.6.4.2) that the calculated order-disorder transition temperature 
of 620C agreed well with the estimated order-disorder transition temperature of approximately 
600C (Figure 88 and Figure 110). 
The comparisons of results discussed in this section validate Criterion One and thus, the required 
level of confidence in the model has been achieved. 

Aging and Phase Stability of Waste Package Outer Barrier 
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Criterion Two 
Do experimental data on TCP formations on base metal grain boundaries and 
TCP and LRO formations in weld metal corroborate with data in peer-reviewed 
literature or fundamental metallurgical phenomena? 
In Section 6.6.5.2, the measurements on Alloy 22 grain boundaries were plotted using an 
Arrhenius fit to conservatively estimate the long-term TCP-phase precipitation on grain 
boundaries. As a measure of the reasonableness of the data plotted in Figure 92, the activation 
energy can be calculated. The slopes of the lines in Figure 92 (after accounting for the log(e) 
factor) are equal to C2/n in Eq. 11. If these slopes are averaged and n is set to be equal to one, 
which is a reasonable value for n (Christian 1981 [DIRS 104964], p. 542, Table IX and p. 19), 
then the activation energy is 378 kJ/mol (or 90 kcal/mol). This value for activation energy 
(for Alloy 22 grain boundary precipitation) is higher than the value of 62 kcal/mol obtained by 
Hodge (1973 [DIRS 104968], p. 378 paragraph 1) for precipitation in Alloy C-276. It is 
expected that the activation energy for Alloy 22 would be slightly higher than that of 
Alloy C-276 primarily due to the differences in chemical composition (alloy C-276 contains 
more Mo and W) and phases formed. As shown in Section 6.6.1, unlike Alloy 22, Alloy C-276 
does not form an oP6-ordered phase. In Alloy 22, it was shown that the formation of the oP6- 
ordered phase competes with the P phase. As a result, it is reasonable that the activation energy 
for C-276 would be slightly lower than that observed for Alloy 22. This activation energy value 
for Alloy 22 grain boundary precipitation is also the within the expected order of magnitude and 
fairly typical for diffusion of relevant elements in Ni (Brandes et al. 1992 [DIRS 104962], 
Chapter 13, pp. 13 to 23). For example, the activation energy for diffusion of Cr in Ni is 
272.6 kJ/mol, that of Fe is 253 to 270 kJ/mol, and that of W in Ni is 299 to 308 kJ/mol. It is 
expected that these activation energy values in binary alloy systems would be lower than that in 
Alloy 22, a multicomponent alloy. 
The data in Figure 92 represent the precipitation kinetics during an isothermal anneal. The 
repository temperature is not expected to remain constant. It was shown that even with this 
activation energy, formation of TCP phases on grain boundaries will not be a concern for 
conditions of less than 300C for a period of 500 years followed by temperatures less than 200C 
for a period of 9,500 years, conditions that bound the repository time-temperature profiles (BSC 
2004 [DIRS 169565], Figure 6.3-57)). 
The comparisons of results discussed in this section validate Criterion Two and, thus, the 
required level of confidence in the model has been achieved. 
Criterion Three 
Do comparisons of volume fraction measurements agree with peer-reviewed 
published literature (where applicable) and/or fundamental metallurgical 
phenomena? 
At present, a computationally based model for phase kinetics in Alloy 22 welds is not available 
to provide insight into the long-term stability of welds. As a result, in Section 6.6.5.3.2, the 
measurements on Alloy 22 welds were plotted using an Arrhenius fit to conservatively estimate 

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the long-term stability of welds. These Arrhenius plots indicated an average activation energy of 
241 kJ/mol for TCP phase formation, which is comparable to but lower than the values of 
250 and 260 kJ/mol reported previously for base metal (Rebak et al. 2000 [DIRS 155013]). It 
was shown that even with a lower activation energy, formation of TCP phases in welds will not 
be a concern for conditions of less than 300C for a period of 500 years followed by 
temperatures less than 200C for a period of 9,500 years, conditions that bound the repository 
time-temperature profiles (BSC 2004 [DIRS 169565], Figure 6.3-57). 
The phase fractions of LRO formations (oP6 phase) in Alloy 22 welds were not measured in this 
study (LRO was only observed). 
The comparisons of results discussed in this section validate Criterion Three and, thus, the 
required level of confidence in the model has been achieved. 
7.7 VALIDATION SUMMARY 
In light of the above discussion, it may be concluded that the inputs used in the aging and phase 
stability model and the model output corroborate well with those reported in handbooks and 
peer-reviewed scientific literature. It is also clear from the above discussion that the validation 
activities performed for building confidence in the model have sufficiently strong scientific 
bases, and that the required level of confidence in the model has been achieved, because the 
model validation criterion described in Technical Work Plan for: Regulatory Integration 
Modeling and Analysis of the Waste Form and Waste Package (BSC 2004 [DIRS 171583]) has 
been satisfied (corroborating data match qualitatively). As a result, it has been demonstrated that 
the aging and phase stability model has been validated for its intended use of providing 
predictive insight into the long-term metallurgical stability of Alloy 22 under relevant repository 
conditions. 
The aging and phase stability model is complex and validation process involves the use of both 
Project generated data and peer-reviewed published literature data. The Thermo-Calc results 
used in analyzing Alloy 22 along with several other Ni-based alloys have been validated using 
comparisons of calculated phase diagrams with published literature, in order of increasing 
complexity, for (1) the binary sub-systems, (2) the pseudo-binary section Nix(Cr3Mo)1x and (3) 
the ternary Ni-Cr-Mo alloy (a surrogate for Alloy 22). Agreement of the calculated phase 
diagrams with published literature is excellent and described in Sections 7.1 through 7.4. In 
Section 7.5, natural analogues were shown to provide confidence in phase stability of metallic 
structures over long periods of time. Section 7.6 described comparisons of the aging and phase 
stability model results and project-generated TCP-phase kinetics data for base metal, and the 
aging and phase stability model was shown to be conservative. Project generated data on LRO 
kinetics were also shown to be in good agreement with the computational aging and phase 
stability model and its estimate of the order-disorder transition temperature (Section 7.6). 
Comparisons with peer-reviewed published literature were used to demonstrate confidence in the 
Arrhenius-type extrapolations for the phase kinetics on grain boundaries and welds derived from 
Project generated data. 

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8. CONCLUSIONS 
The CALPHAD approach has been applied to the study of statics (stability) and kinetics (aging) 
of phase formation and evolution in Ni-based alloys. At equilibrium, Alloy 22, at its nominal 
compositions and at low temperatures, should exhibit, besides the fcc matrix, long-range order of 
Ni2Cr-type, complex FrankKasper phases (here, the P phase), carbides and silicides. The 
kinetics of LRO formation occurs at relatively low temperatures, and therefore, does not favor 
the formation of the ordered phase of Ni2Cr-type as the phase formation kinetics are primarily 
driven by diffusion. Alloys homogenized (or annealed) at high temperatures and quenched at 
relevant repository conditions should not display any deleterious phase. Extrapolation of 
computationally derived TTT curves to lower temperatures, which bound repository timetemperature 
profiles (i.e., less than 300C for a period of 500 years followed by temperatures of 
less than 200C for a period of 9,500 years (BSC 2004 [DIRS 169565], Figure 6.3-57)), indicates 
that forming the P- or oP6-ordered phases from the fcc solid solution will not be a concern. 
After aging for 16,000 hours at 593C, P phase was found at Alloy 22 grain boundaries. At 
higher temperatures (as much as 760C for the same aging time),  and P phases formed on grain 
boundaries and within the grains. Grain boundary carbides also form at 593C and higher, but 
the amount of carbide is small compared to the  and P phases. A small amount of s phase 
forms in Alloy 22 after 16,000 hours at 704C and 760C. LRO was seen after aging for 
1,000 hours at 538C and 593C and for 30,000 hours at 427C (shown in Table 6), but ordering 
most likely begins at shorter times. 
The experimental analyses previously discussed assume that the kinetics of formation of the  
and P phases are similar and that the amount of carbide and s phase present is too small to affect 
the measured rates of precipitation (Assumption 5.1). Minor compositional changes in Alloy 22 
are also expected to have little or no effect on the rate of precipitation. The amounts of carbide 
and s phase tend to be low in the samples examined thus far. Therefore, the rates of formation 
of these phases are not likely to contribute significantly to the overall performance of the waste 
package. Studies from existing literature (Section 5.1) showed that the  and P phases are very 
similar, and the rates at which they form are likely to be similar. 
The experimental analyses previously discussed also assume that the precipitation mechanism 
operating at the high temperatures studied also operates at the lower temperatures expected in the 
proposed repository and that the phases seen at the higher temperatures are stable at the lower 
temperatures (Assumption 5.2). Information from natural analogues (Section 6.7.2) showed that 
the stability of the metallic structures in josephinite over millions of years suggests that no lowtemperature 
mechanism with rates significantly greater than predicted exists. Thus, this provides 
confidence in the implicit assumption that the high temperature mechanisms used to extrapolate 
kinetics are the same as those at lower temperatures that are expected under repository 
conditions. 
The present study shows that formation of TCP or ordered oP6 phases in Alloy 22 base metal 
and welds (which are deemed to be similar to base metal) will not be a concern for conditions of 
less than 300C for a period of 500 years followed by temperatures less than 200C for 9,500 
years, conditions that bound the repository time-temperature profiles (BSC 2004 [DIRS 169565], 
Figure 6.3-57). 

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8.1 THE ROLE OF W IN THE STABILITY OF NICKEL-BASED ALLOYS 
From experiments and the results of the present study, it is apparent that Cr and Mo favor the 
formation of TCP phases (s, P, and ). It was also noted that in the pure binary forms, Cr is the 
only element that favors the formation of the oP6-ordered phase Ni2Cr. The effect of Mo on 
oP6-phase formation is more subtle, as revealed from the study. Indeed, in the pure binary form, 
Ni2Mo is barely stable (Section 7.1). However, it was shown experimentally 
(Karmazin et al. 1994 [DIRS 161444]) that at a low mole fraction of Mo, the substitution of Cr 
by Mo enhances the formation of the oP6-ordered phase, as indicated by an increase in the 
critical orderdisorder temperature. The gradual substitution of Cr by Mo from Ni2Cr to Ni2Mo 
does not lead to a gradual instability of the order phase as was initially anticipated. The role of 
W on the stability of oP6-ordered phase is more obvious. The gradual substitution of Cr by W 
gradually leads to a destabilization of the ordered phase, and the oP6 Ni2W ordered phase is 
clearly unstable. It is worth recalling that Alloy 22 has (in wt %) 21.2 Cr13.5 Mo3 W, 
whereas in Alloy 59 has 23 Cr16 Mo, with no W. From the above observations, it is concluded 
that the oP6-ordered phase will occur at higher temperature (i.e., will be more stable) in Alloy 59 
than in Alloy 22 (less unstable effect on the ordered phase caused by the absence of W in 
Alloy 59). At the same time, because more Cr and Mo are present in Alloy 59 than in Alloy 22, 
it is expected that at low temperatures, the stability of the complex TCP phases will be more 
favored in Alloy 59 than in Alloy 22 (Heino 2000 [DIRS 161799]). Hence, because of this 
double effect of the absence of W in Alloy 59, it is believed that Alloy 22 is a more promising 
alloy than Alloy 59, at least when in operation at low temperatures (below 800C), as is the case 
under expected repository conditions. 
8.2 APPLICABILITY OF RANGES OF ALLOY 22 CHEMICAL COMPOSITION 
In the computational analyses and measurements conducted on Alloy 22 samples presented here, 
the Alloy 22 chemical composition was within that specified by ASTM specification B575 
(UNS N06022). In addition, five heats of Alloy 22 base metal were used in performing the 
measurements on test specimens, and the chemical composition of these heats are summarized in 
Table 11. In all heats, the Alloy 22 chemical composition was more restricted than that specified 
in ASTM specification B575 (UNS N06022) as shown in Table 12. The nominal chemical 
composition of the ternary NiCrMo alloy that was used as a surrogate for Alloy 22 in the 
Thermo-Calc/DICTRA simulations also agreed well with the range of chemical compositions 
from these five heats (also shown in Table 12). This comparative summary shows that the 
chemical compositions of ASTM specification B575, the five heats tested, and the nominal 
composition of the ternary surrogate for Alloy 22 are consistent and in agreement. Thus, the 
conclusions presented here are applicable to a narrower range (as compared to the ASTM 
specification B575) of chemical compositions for Ni, Cr, Mo, and W, which were modeled with 
Thermo-Calc and DICTRA. Ni, Cr, Mo, and W are the most dominant elements in TCP and 
oP6-ordered phases in Alloy 22. 

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Table 11. Summary of Alloy 22 Chemical Composition of Heats Tested 
Element 2277-0-3264a 2277-0-3270a 2277-8-3121a 2277-8-3235b 2277-9-3243a 
AI      
C 0.004 0.003 0.003 0.003 0.002 
Co 1.14 1.96 0.48 1.31 1.04 
Cr 21.3 21.2 21.24 21.4 21.28 
Cu      
Fe 4.4 4.5 3.82 3.94 3.6 
Mg      
Mn 0.29 0.25 0.3 0.24 0.28 
Mo 13.4 13.3 13.43 13.47 13.29 
N      
Nb(Cb)      
Ni BAL BAL BAL BAL BAL 
P 0.01 0.006 0.006 0.008 0.007 
S 0.002 0.003 0.001 0.001 0.002 
Si 0.047 0.038 0.035 0.023 0.036 
Ta      
Ti      
V 0.17 0.14 0.17 0.17 0.14 
W 2.9 3.0 2.85 2.87 2.8 
Sources: a Summers 1999 [DIRS 171396], pp. 9 and 17. 
b Summers 2000 [DIRS 171397], p. 1. 

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Table 12. Summary of Alloy 22 Chemical Compositions (ASTM B575, Heats Tested, and Ternary Alloy 22 
Surrogate) 
Element ASTM B575 
Chemical Compositional 
Range of Heats Tested 
Nominal Composition of 
Ternary Surrogate for Alloy 22 
AI    
C 0.015 max 0.004 max  
Co 2.5 max 2.0 max  
Cr 20.0 to 22.5 21.2 to 21.4 21.1 
Cu    
Fe 2.0 to 6.0 3.6 to 4.5  
Mg    
Mn 0.50 max 0.30 max  
Mo 12.5 to 14.5 13.3 to 13.5 13.5 
N    
Nb(Cb)    
Ni BAL BAL BAL 
P 0.02 max 0.01 max  
S 0.02 max 0.003 max  
Si    
Ta    
Ti    
V 0.35 max 0.2 max  
W 2.5 to 3.5 2.8 to 3.0 3.0 
8.3 SUMMARY OF DEVELOPED DATASETS 
The developed data from this report that have been presented and discussed in Sections 6 and 7 
have been summarized in Table 13. 
Table 13. Summary of Developed Datasets 
Data Name DTN Data Presented in this Report 
Property and Phase Kinetics 
Diagrams LL030106312251.013 Sections 6.6.1.1 through 6.6.4.3 
Validation of Computational Model LL030106412251.014 Sections 7.1 through 7.4 
Developed Data from Alloy 22 
Volume Fraction Measurements LL030606912251.020 Sections 6.6.5 and 7.5 
8.4 YUCCA MOUNTAIN REVIEW PLAN ACCEPTANCE CRITERIA 
Yucca Mountain Review Plan, Final Report (NRC 2003 [DIRS 163274]) contains Acceptance 
Criteria that are intended to establish the basis for the review of the material contained in the 
License Application. As this model report serves, in part, as the basis for the License 
Application, it is important to show how the information contained herein addresses each of the 
applicable YMRP Acceptance Criteria. 

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The YMRP Acceptance Criteria that are applicable to this report are identified in Technical Work 
Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package 
(BSC 2004 [DIRS 171583], Table 3-1). For each applicable criterion, the criterion is quoted in 
italics, followed by pointers to where within the report the information addressing the criterion 
can be found. In some cases, the criterion is only partially addressed in this report. A 
demonstration of full compliance requires a review of multiple reports. 
8.4.1 System Description and Demonstration of Multiple Barriers 
The following Acceptance Criteria are from Section 2.2.1.1.3 of Yucca Mountain Review Plan, 
Final Report (NRC 2003 [DIRS 163274]). Although the criterion pertains to multiple barriers, 
only the waste package outer barrier is addressed in this report. As such, the responses below 
pertain to only that barrier. 
Acceptance Criterion 1 - Identification of Barriers Is Adequate 
Barriers relied on to achieve compliance with 10 CFR 63.113(b), as 
demonstrated in the total system performance assessment, are adequately 
identified, and are clearly linked to their capability. 
The effects of aging and phase stability on waste package outer barrier performance are 
described in Sections 1, 6.1, and 6.2. 
Acceptance Criterion 2 - Description of Barrier Capability to Isolate Waste Is Acceptable 
The capability of the identified barriers to prevent or substantially reduce the rate 
of movement of water or radionuclides from the Yucca Mountain repository to the 
accessible environment, or prevent the release or substantially reduce the release 
rate of radionuclides from the waste is adequately identified and described: 
(1) The information on the time period over which each barrier performs its 
intended function, including any changes during the compliance period, is 
provided; 
(2) The uncertainty associated with barrier capabilities is adequately described; 
(3) The described capabilities are consistent with the results from the total system 
performance assessment; and 
(4) The described capabilities are consistent with the definition of a barrier at 10 
CFR 63.2. 
The effects of aging and phase stability on waste package outer barrier performance are 
described in Sections 1, 6.1, and 6.2. 

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Acceptance Criterion 3 - Technical Basis for Barrier Capability Is Adequately Presented 
The technical bases are consistent with the technical basis for the performance 
assessment. The technical basis for assertions of barrier capability is 
commensurate with the importance of each barriers capability and the 
associated uncertainties. 
The effects of aging and phase stability on waste package outer barrier performance are 
described in Sections 1, 6.1, and 6.2. 
8.4.2 Degradation of Engineered Barriers 
The following acceptance criteria are from Section 2.2.1.3.1.3 of Yucca Mountain Review Plan, 
Final Report (NRC 2003 [DIRS 163274]). 
Acceptance Criterion 1  System Description and Model Integration are Adequate 
(1) TSPA adequately incorporates important design features, physical phenomena 
and couplings and uses consistent assumptions throughout the degradation of 
engineered barriers abstraction process 
The appropriate design features and applicable physical phenomena, as well as environmental 
factors and their coupling are addressed in Sections 6.1 and 6.3. 
(2) Abstraction uses assumptions, technical bases, data and models that are 
appropriate and consistent with [those used] in other abstractions. 
Throughout this report, the performed analyses use assumptions, technical bases, input data and 
models that appropriately reflect the design and contents of the metallurgical stability of Alloy 
22 used in the waste package outer barrier. The assumptions are addressed in Section 5. The 
data, technical bases and models are addressed in Sections 4.1 and 6. This information is used in 
a manner that is consistent with other abstractions of processes associated with the degradation 
of the waste package. 
(3) The descriptions of the engineered barriers, design features, degradation 
processes, physical phenomena, and couplings that may affect the degradation of 
the engineered barriers are adequate. 
Detailed descriptions of the metallurgical stability processes relevant for the Alloy 22 used in the 
waste package outer barrier (Sections 6.1 and 6.3), and the physical phenomena and their 
couplings that may affect Alloy 22 metallurgical stability (Sections 6.1 and 6.3) are provided. 
(4) Initial and boundary conditions are propagated consistently throughout the 
abstraction process. 
The initial and relevant environmental boundary conditions for the performed analyses 
(Section 6.5) are described and used in developing the aging and phase stability model. 

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ANL-EBS-MD-000002 REV 02 8-7 September 2004 
(5) Sufficient technical basis for the inclusion and exclusion of FEPs are 
provided; 
This model report provides the basis for the exclusion of FEP 2.1.11.06.0A (Thermal 
sensitization of waste packages) in TSPA-LA (Total System Performance Assessment for the 
License Application) as discussed in Section 6.6.4. 
(6) In-Package Criticality 
Not applicable to this report 
(7) Guidance in NUREG 1297 and NUREG 1298 [re: Expert Elicitation] are 
followed. 
Not applicable to this report; expert elicitation is not used. 
Acceptance Criterion 2  Data Are Sufficient for Model Justification 
(1) Parameters used to evaluate the degradation of EBS are adequately justified; 
The input data and parameters used for the aging and phase stability model come, primarily, 
from commercially available thermodynamic and kinetic databases that have been formulated to 
accurately simulate the metallurgical phenomena of Alloy 22 (Section 7). In addition, Alloy 22 
experimental data generated by the project (Section 4.1) is used to support and compare with the 
results of the computational model. Justification for the use of specific data is typically provided 
in the section in which the data are initially discussed (Section 4.1) and used (Section 7). 
(2) Sufficient data have been collected to establish initial and boundary 
conditions; 
Extensive scientific investigations and experiments have been performed by the project to 
develop the data necessary to support the analyses provided in this model report (Sections 4.1 
and 6.6). All initial and boundary conditions are adequately and appropriately established and 
justified. 
(3) Data on the degradation of the engineered barriers (e.g.  general and 
localized corrosion, microbially induced corrosion, galvanic interactions, 
hydrogen embrittlement and phase stability) are based on laboratory 
measurements, site-specific field measurements, industrial and/or natural analogs 
and tests designed to replicate anticipated conditions. As appropriate, sensitivity 
or uncertainty analyses are provided and are shown to be adequate. 
Data related to the various potential degradation modes for the metallurgical stability of Alloy 22 
are discussed in Sections 6.1 and 6.2. 
(4) Degradation models for the applicable processes are adequate. For example, 
general and localized corrosion, microbially induced corrosion, galvanic 

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interactions, hydrogen embrittlement and phase stability are given appropriate 
consideration and treatment. 
The various models related to the potential degradation modes for the metallurgical stability of 
Alloy 22 are discussed in Sections 6.1 and 6.2. 
Acceptance Criterion 3  Data Uncertainty is Characterized and Propagated through the 
Model Abstraction 
(1) Models use parameter values, assumed ranges, probability distributions 
and/or bounding assumptions that are technically defensible, reasonably account 
for uncertainties and variabilities, and do not result in under-representation of 
the risk estimate. 
The computational model developed in this model report uses parameter values and assumed 
ranges, that are technically defensible, reasonably account for uncertainties and variabilities, and 
do not result in under-representation of the risk estimate. Discussion and consideration of the 
uncertainties associated with specific data are addressed in detail. The effects of data 
uncertainties and computational accuracy on model results are discussed in Section 6.7. 
(2) Appropriate parameters, based on techniques that may include laboratory 
experiments, field measurements, and industrial analogs are used. 
The computational model employed in this model report use data and parameters that have been 
developed based on the CALPHAD method to simulate the metallurgical phenomena of Alloy 22 
(Section 6.5). Peer reviewed and industrial literature, together with project-generated 
experimental measurements, are used for model validation in Sections 7.1 through 7.5. 
(3) Assumed range of values and probability distributions for parameters used in 
conceptual and process-level models are not likely to underestimate the actual 
degradation and failure of engineered barriers. 
As discussed in Section 7.5, the model validation results indicate the computational model 
consistently gives results that are conservative compared to experimental measurements. 
(4) Nondestructive examination. 
Not applicable; no NDE of Alloy 22 material was involved with the development of this report. 
(5) Where sufficient data do not exist, the definition of parameter values and 
conceptual models is based on appropriate use of other sources, such as expert 
elicitation. 
The available data is generally sufficient to support the definition of parameter values and the 
Alloy 22 aging and phase stability conceptual model. 

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Acceptance Criterion 4  Model Uncertainty is Characterized and Propagated Through the 
Model Abstraction 
(1) Alternative modeling approaches are considered and are consistent with 
available data and current scientific understanding. 
Alternative modeling approaches that are consistent with available data and current scientific 
understanding are considered and discussed in Section 6.4. 
(2) Consideration of conceptual model uncertainty is consistent with available 
site characterization data, laboratory experiments,  and the treatment of 
uncertainty does not result in under-estimation of the risk estimate. 
Consideration of uncertainties in the models used in this model report is an integral part of the 
model development and validation processes. Conceptual model uncertainty is consistent with 
the information that has been developed from computational simulations (Sections 6 and 7). 
Care is taken to ensure that the treatment of uncertainty does not result in underestimation of the 
risk estimate. As discussed in Section 7.5, the model validation results show that the 
computational model consistently gives results that are conservative compared to experimental 
measurements. 
(3) Alternative modeling approaches, consistent with available data and current 
scientific understanding, are used and the modeling results are evaluated using 
tests that are sensitive to the processes modeled. 
Alternative modeling approaches, consistent with available data and current scientific 
understanding, are considered (Section 6.4). In all instances, it is determined that the base case 
model provides a more credible modeling basis than would be achieved through the use of the 
alternative models. Thus, although due consideration is given to the use of alternative modeling 
approaches, no alternative models are used in TSPA-LA. 
Acceptance Criterion 5  Model Abstraction Output Is Supported By Objective 
Comparisons 
(1) Models implemented in this total system performance assessment abstraction 
provide results consistent with output from detailed process-level models and or 
empirical observations (laboratory and field testing, and/or natural analogs). 
The results of the computational Aging and Phase Stability model developed in this model report 
(this model is not implemented in a total system performance assessment abstraction) are 
compared with empirical observations (laboratory) as part of the model validation (Section 7.5). 
(2) Corrosion models. 
Not applicable; this report does not include numerical models. 
(3) Evidence is sufficient to show that models will not underestimate the actual 
degradation and failure of engineered barriers. 

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ANL-EBS-MD-000002 REV 02 8-10 September 2004 
In those instances where there is doubt about the appropriateness or accuracy of the models or 
data, care is taken to select a conservative approach or conservative data that would result in an 
over-estimation of risk. The model validation results show that the computational model 
consistently gives results that are conservative compared to experimental measurements 
(Section 7.5). 
(4) Mathematical degradation models are based on the same environmental 
parameters, material factors, assumptions and approximations shown to be 
appropriate for closely analogous applications. 
The computational model used in this model report is based on the well-established CALPHAD 
approach that involves the coupling of phase diagrams calculations for multicomponent alloy 
systems with other forms of thermo-chemical inputs to determine phase formation, proportions, 
and transformations. As a result, the model is based on the same environmental parameters, 
material factors, assumptions and approximations that are appropriate for closely analogous 
applications (Section 6.5). 
(5) Accepted and well documented procedures are used to construct and test the 
numerical models that simulate the EB chemical environment and degradation of 
EB; 
The development and testing of the models used to simulate the metallurgical stability of 
Alloy 22 is performed in accordance with previously established well-documented Yucca 
Mountain project procedures that are based on industry established norms. These procedures 
also establish the appropriate quality assurance requirements for such activities and appropriate 
checking, auditing and other activities performed to ensure the adequacy and appropriateness of 
the models (Section 2). 
(6)  
Not applicable to the scope of this report. 

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9. INPUTS AND REFERENCES 
9.1 DOCUMENTS CITED 
161440 Agren, J. 1992. Computer Simulations of Diffusional Reactions in Complex Steels. 
ISIJ International, 32, (3), 291-296. Tokyo, Japan: Iron and Steel Institute of Japan. 
TIC: 254255. 
161461 Andersson, J.-O.; Guillermet, A.F.; Hillert, M.; Jansson, B.; and Sundman, B. 1986. 
A Compound-Energy Model of Ordering in a Phase with Sites of Different 
Coordination Numbers. Acta Metallurgica, 34, (3), 437-445. Elmsford, New York: 
Pergamon Press. TIC: 253831. 
161462 Ansara, I.; Dupin, N.; and Sundman, B. 1998. Reply to the Paper: 'When is a 
Compound Energy Not a Compound Energy? A Critique of the 2-Sublattice 
Order/Disorder Model.' Calphad, 21, (4), 535-542. New York, New York: 
Elsevier. TIC: 253806. 
163390 Bernard, C.; Pons, M.; Blanquet, E.; and Madar, R. 1999. Thermodynamic 
Calculations as the Basis for CVD Production of Silicide Coatings. MRS Bulletin, 
24, (4), 27-31. Warrendale, Pennsylvania: Materials Research Society. 
TIC: 254150. 
161463 Bloom, D.S. and Grant, N.J. 1954. An Investigation of the Systems Formed by 
Chromium, Molybdenum, and Nickel. Journal of Metals, 6, (2), 261-268. New 
York, New York: American Institute of Mining and Metallurgical Engineers. 
TIC: 253832. 
154716 Botto, R.I. and Morrison, G.H. 1976. Josephinite: A Unique Nickel-Iron. 
American Journal of Science, 276, (3), 241-274. New Haven, Connecticut: Yale 
University, Kline Geology Laboratory. TIC: 249797. 
104962 Brandes, E.A. and Brook, G.B., eds. 1992. Smithells Metals Reference Book. 7th 
Edition. Oxford, United Kingdom: Butterworth-Heinemann. TIC: 246620. 
168796 BSC (Bechtel SAIC Company) 2003. Risk Information to Support Prioritization of 
Performance Assessment Models. TDR-WIS-PA-000009 REV 01 ICN 01, with 1 
errata. Las Vegas, Nevada: Bechtel SAIC Company. ACC: MOL.20021017.0045; 
DOC.20031014.0003. 
169997 BSC 2004. FEPs Screening of Processes and Issues in Drip Shield and Waste 
Package Degradation. ANL-EBS-PA-000002, Rev. 03. Las Vegas, Nevada: Bechtel 
SAIC Company. 
169565 BSC 2004. Multiscale Thermohydrologic Model. ANL-EBS-MD-000049 REV 02. 
Las Vegas, Nevada: Bechtel SAIC Company. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 9-2 September 2004 
168361 BSC 2004. Q-List. 000-30R-MGR0-00500-000-000 REV 00. Las Vegas, Nevada: 
Bechtel SAIC Company. ACC: ENG.20040721.0007. 
170992 BSC 2004. Safety Classification of SSCs and Barriers. 000-00C-MGR0-01000-000- 
00A. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20040721.0005. 
171583 BSC 2004. Technical Work Plan For: Regulatory Integration Modeling and Analysis 
of the Waste Form and Waste Package. TWP-WIS-MD-000009, REV 00, ICN 01. 
Las Vegas, Nevada: Bechtel SAIC Company. ACC: DOC.20040910.0001. 
104964 Christian, J.W. 1981. Equilibrium and General Kinetic Theory. Part I of The 
Theory of Transformations in Metals and Alloys. 2nd Edition. Pages 19, 438, 542. 
New York, New York: Pergamon Press. TIC: 245378. 
104966 Cieslak, M.J.; Headley, T.J.; and Romig, A.D., Jr. 1986. The Welding Metallurgy of 
Hastelloy Alloys C-4, C-22, and C-276. Metallurgical Transactions A, 17A, (11), 
2035-2047. Warrendale, Pennsylvania: Metallurgical Society of AIME. 
TIC: 233952. 
157916 Curry, P.M. and Loros, E.F. 2002. Project Requirements Document. TER-MGRMD-
000001 REV 00. Las Vegas, Nevada: Bechtel SAIC Company. 
ACC: MOL.20020806.0027. 
154749 Dick, H.J.B. 1974. Terrestrial NickelIron from the Josephine Peridotite, Its 
Geologic Occurrence, Associations, and Origin. Earth and Planetary Science 
Letters, 24, (2), 291-298. Amsterdam, The Netherlands: North-Holland. 
TIC: 249849. 
161439 Dinsdale, A.T. 1991. SGTE Data for Pure Elements. Calphad, 15, (4), 317-425. 
New York, New York: Pergamon Press. TIC: 253829. 
171539 DOE (U.S. Department of Energy) 2004. Quality Assurance Requirements and 
Description. DOE/RW-0333P, Rev. 16. Washington, D.C.: U.S. Department of 
Energy, Office of Civilian Radioactive Waste Management. 
ACC: DOC.20040907.0002. 
161442 Engstrm, A.; Hglund, L.; and Agren, J. 1994. Computer Simulation of Diffusion 
in Multiphase Systems. Metallurgical and Materials Transactions A. Physical 
Metallurgy and Materials Science, 25A, (6), 1127-1134. Warrendale, Pennsylvania: 
Minerals, Metals, & Materials Society. TIC: 253804. 
161437 Frank, F.C. and Kasper, J.S. 1958. Complex Alloy Structures Regarded as Sphere 
Packings. I. Definitions and Basic Principles. Acta Crystallographica, 11, (3), 
184-190. Copenhagen, Denmark: Ejnar Munksgaard. TIC: 253800. 
161438 Frank, F.C. and Kasper, J.S. 1959. Complex Alloy Structures Regarded as Sphere 
Packings. II. Analysis and Classification of Representative Structures. Acta 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 9-3 September 2004 
Crystallographica, 12, (7), 483-499. Copenhagen, Denmark: Ejnar Munksgaard. 
TIC: 253835. 
100859 Gdowski, G.E. 1991. Survey of Degradation Modes of Four Nickel-Chromium- 
Molybdenum Alloys. UCRL-ID-108330. Livermore, California: Lawrence 
Livermore National Laboratory. ACC: NNA.19910521.0010. 
154750 Gpel, C.; Manhs, G.; and Allgre, C.J. 1990. U-Pb Isotope Systematics in 
Josephinites and Associated Rocks. Earth and Planetary Science Letters, 97, (1/2), 
18-28. Amsterdam, The Netherlands: Elsevier. TIC: 249851. 
161799 Heino, S. 2000. Role of Mo and W During Sensitization of Superaustenitic Stainless 
SteelCrystallography and Composition of Precipitates. Metallurgical and 
Materials Transactions A. Physical Metallurgy and Materials Science, 31A, (8), 
1893-1905. Warrendale, Pennsylvania: Minerals, Metals & Materials Society. 
TIC: 254142. 
161454 Hilliard, J.E. and Cahn, J.W. 1961. An Evaluation of Procedures in Quantitative 
Metallography for Volume-Fraction Analysis. Transactions of the Metallurgical 
Society of AIME, 221, (2), 344-352. New York, New York: American Institute of 
Mining, Metallurgical, and Petroleum Engineers. TIC: 253830. 
161452 Hirabayashi, M.; Koiwa, M.; Tanaka, K.; Tadaki, T.; Saburi, T.; Nenno, S.; and 
Nishiyama, H. 1969. An Experimental Study on the Ordered Alloy Ni2Cr. 
Transactions of the Japan Institute of Metals, 10, (5), 365-371. Sendai, Japan: Japan 
Institute of Metals. TIC: 254259. 
104968 Hodge, F.G. 1973. Effect of Aging on the Anodic Behavior of Ni-Cr-Mo Alloys. 
Corrosion, 29, (10), 375-383. Houston, Texas: National Association of Corrosion 
Engineers. TIC: 240167. 
161441 Jena, A.K.; Rajendraprasad, S.B.; and Gupta, K.P. 1989. The Cr-Mo-Ni 
(Chromium-Molybdenum-Nickel) System. Journal of Alloy Phase Diagrams, 5, (3), 
164-167. Calcutta, India: Indian Institute of Metals. TIC: 253833. 
154881 Karmazin, L. 1982. Lattice Parameter Studies of Structure Changes of NiCr Alloys 
in the Region of Ni2Cr. Materials Science and Engineering, 54, 247-256. 
Lausanne, Switzerland: Elsevier. TIC: 249655. 
161444 Karmazin, L.; Krejc, J.; and Zeman, J. 1994. y[gamma] Phase and Ni2Cr-Type 
Long-Range Order in Ni-rich Ni-Cr-Mo Alloys. Materials Science and Engineering 
A. Structural Materials: Properties, Microstructure and Processing, A183, (1-2), 
103-109. Lausanne, Switzerland: Elsevier. TIC: 253803. 
154746 Krishnarao, J.S.R. 1964. Native Nickel-Iron Alloy, Its Mode of Occurrence, 
Distribution and Origin. Economic Geology, 59, (3), 443-448. Lancaster, 
Pennsylvania: Economic Geology Publishing. TIC: 249850. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 9-4 September 2004 
104970 Leonard, R.B. 1969. Thermal Stability of Hastelloy Alloy C-276. Corrosion, 25, 
(5), 222-228. Houston, Texas: National Association of Corrosion Engineers. 
TIC: 240456. 
118757 Massalski, T.B.; Okamoto, H.; Subramanian, P.R.; and Kacprzak, L. 1996. Binary 
Alloy Phase Diagrams. 2nd Edition. Three volumes. Materials Park, Ohio: ASM 
International. TIC: 242462. 
163274 NRC (U.S. Nuclear Regulatory Commission) 2003. Yucca Mountain Review Plan, 
Final Report. NUREG-1804, Rev. 2. Washington, D.C.: U.S. Nuclear Regulatory 
Commission, Office of Nuclear Material Safety and Safeguards. TIC: 254568. 
161275 Pickering, F.B. 1976. Physical Metallurgy of Stainless Steel Developments. 
International Metals Reviews, 21, 227-268. Metals Park, Ohio: American Society 
for Metals. TIC: 253801. 
161265 Porter, D.A. and Easterling, K.E. 1992. Diffusion along Dislocations. Section 
2.7.2 of Phase Transformations in Metals and Alloys. 2nd Edition. Pages 102-103. 
New York, New York: Chapman & Hall. TIC: 254148. 
163029 Porter, D.A. and Easterling, K.E. 1997. Case Studies. Section 6.7 of Phase 
Transformations in Metals and Alloys. 2nd Edition. Pages 428-437. New York, 
New York: Chapman & Hall. TIC: 254148. 
163028 Porter, D.A. and Easterling, K.E. 1997. Theories of Martensite Nucleation. 
Section 6.3 of Phase Transformations in Metals and Alloys. 2nd Edition. Pages 397- 
409. New York, New York: Chapman & Hall. TIC: 254148. 
146956 Raghavan, M.; Berkowitz, B.J.; and Scanlon, J.C. 1982. Electron Microscopic 
Analysis of Heterogeneous Precipitates in Hastelloy C-276. Metallurgical 
Transactions A, 13A, 979-984. Warrendale, Pennsylvania: Metallurgical Society of 
AIME and American Society for Metals. TIC: 240058. 
154707 Raghavan, M.; Mueller, R.R.; Vaughn, G.A.; and Floreen, S. 1984. Determination 
of Isothermal Sections of Nickel Rich Portion of Ni-Cr-Mo System by Analytical 
Electron Microscopy. Metallurgical Transactions A, 15A, (5), 783-792. New York, 
New York: Metallurgical Society of American Institute of Mining, Metallurgical, 
and Petroleum Engineers. TIC: 240057. 
102797 Rebak, R.B. and Koon, N.E. 1998. Localized Corrosion Resistance of High Nickel 
Alloys as Candidate Materials for Nuclear Waste Repository. Effect of Alloy and 
Weldment Aging at 427C for up to 40,000 H. Corrosion 98. Pages 153/1-153/13. 
Houston, Texas: National Association of Corrosion Engineers. TIC: 245068. 
155013 Rebak, R.B.; Summers, T.S.E.; and Carranza, R.M. 2000. Mechanical Properties, 
Microstructure and Corrosion Performance of C-22 Alloy Aged at 260C to 800C. 
Scientific Basis for Nuclear Waste Management XXIII, Symposium held November 
29-December 2, 1999, Boston, Massachusetts. Smith, R.W. and Shoesmith, D.W., 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 9-5 September 2004 
eds. 608, 109-114. Warrendale, Pennsylvania: Materials Research Society. 
TIC: 249052. 
161464 Redlich, O. and Kister, A.T. 1948. Algebraic Representation of Thermodynamic 
Properties and the Classification of Solutions. Industrial and Engineering 
Chemistry, 40, (2), 345-348. Easton, Pennsylvania: American Chemical Society. 
TIC: 253808. 
162684 Reed-Hill, R.E. 1973. Physical Metallurgy Principles. 2nd Edition. Boston, 
Massachusetts: PWS-KENT Publishing Company. TIC: 254402. 
161445 Rideout, S.; Manly, W.D.; Kamen, E.L.; Lement, B.S.; and Beck, P.A. 1951. 
Intermediate Phases in Ternary Alloy Systems of Transition Elements. Journal of 
Metals, 3, (10), 872-876. New York, New York: American Institute of Mining and 
Metallurgical Engineers. TIC: 253802. 
162973 Royal Institute of Technology. 1998. DICTRA & Diffusivities. DICTRA User's 
Guide. Version: 20. Pages 54-63. Stockholm, Sweden: Royal Institute of 
Technology, Department of Materials Science and Engineering. TIC: 254256. 
104975 Saunders, N. and Miodownik, A.P. 1998. CALPHAD, Calculation of Phase 
Diagrams: A Comprehensive Guide. New York, New York: Pergamon Press. 
TIC: 245913. 
161800 Shen, T.H. 1999. TEM Observation of Ordering in C-22 Alloy. Technical 
memorandum from T.H. Shen to T. Summers, September 30, 1999. 
ACC: MOL.20030422.0333. 
161801 Shen, T.H. 2000. X-ray Microanalysis of Precipitates in Alloy C-22. Technical 
memorandum from T.H. Shen to T. Summers, March 20, 2000. 
ACC: MOL.20030422.0335. 
154989 Shoemaker, D.P. and Shoemaker, C.B. 1988. Icosahedral Coordination in Metallic 
Crystals. Chapter 1 of Introduction to Quasicrystals. Jaric, M.V., ed. Aperiodicity 
and Order Volume 1. San Diego, California: Academic Press. TIC: 245244. 
163389 Small, C.J. and Saunders, N. 1999. The Application of CALPHAD Techniques in 
the Development of a New Gas-Turbine Disk Alloy. MRS Bulletin, 24, (4), 22-26. 
Warrendale, Pennsylvania: Materials Research Society. TIC: 254150. 
163392 Spear, K.E.; Besmann, T.M.; and Beahm, E.C. 1999. Thermochemical Modeling of 
Glass: Application to High-Level Nuclear Waste Glass. MRS Bulletin, 24, (4), 37- 
44. Warrendale, Pennsylvania: Materials Research Society. TIC: 254150. 
161436 Spencer, P.J. 1999. Computer Simulations from Thermodynamic Data: Materials 
Production and Development. MRS Bulletin, 24, (4), 18-19. Warrendale, 
Pennsylvania: Materials Research Society. TIC: 254150. 

Aging and Phase Stability of Waste Package Outer Barrier 
ANL-EBS-MD-000002 REV 02 9-6 September 2004 
171396 Summers, T. 2002. Phase Stability Studies - LLNL Aging Studies. SN-LLNL-SCI- 
444-V1. Pages 12-74 ACC: MOL.20020624.0336; MOL.20020624.0337. 
171397 Summers, T. 2000. E-20-67 Phase Stability Studies. Scientific Notebook SN-LLNLSCI-
393-V1. Pages 1-156 ACC: MOL.20020117.0206; MOL.20020117.0207. 
110249 Summers, T. and Turchi, P. 1999. Aging and Phase Stability of Waste Package Outer 
Barrier. UCRL-ID-134582. Livermore, California: Lawrence Livermore National 
Laboratory. TIC: 246033. 
154854 Summers, T.S.E.; Rebak, R.B.; and Seeley, R.R. 2000. Influence of Thermal Aging 
on the Mechanical and Corrosion Properties of C-22 Alloy Welds. UCRL-JC- 
137727. Livermore, California: Lawrence Livermore National Laboratory. 
ACC: MOL.20010517.0257. 
146915 Summers, T.S.E.; Wall, M.A.; Kumar, M.; Matthews, S.J.; and Rebak, R.B. 1999. 
Phase Stability and Mechanical Properties of C-22 Alloy Aged in the Temperature 
Range 590 to 760C for 16,000 Hours. Scientific Basis for Nuclear Waste 
Management XXII, Symposium held November 30-December 4, 1998, Boston, 
Massachusetts. Wronkiewicz, D.J. and Lee, J.H., eds. 556, 919-926. Warrendale, 
Pennsylvania: Materials Research Society. TIC: 246426. 
161460 Sundman, B. and Agren, J. 1981. A Regular Solution Model for Phases with 
Several Components and Sublattices, Suitable for Computer Applications. Journal 
of Physics and Chemistry of Solids, 42, (4), 297-301. New York, New York: 
Pergamon Press. TIC: 253807. 
163391 Sundman, B. and Agren, J. 1999. Computer Applications in the Development of 
Steels. MRS Bulletin, 24, (4), 32-36. Warrendale, Pennsylvania: Materials 
Research Society. TIC: 254150. 
163393 Tanaka, T.; Hack, K.; and Hara, S. 1999. Use of Thermodynamic Data to Determine 
Surface Tension and Viscosity of Metallic Alloys. MRS Bulletin, 24, (4), 45-50. 
Warrendale, Pennsylvania: Materials Research Society. TIC: 254150. 
104991 Tawancy, H.M.; Herchenroeder, R.B.; and Asphahani, A.I. 1983. High- 
Performance Ni-Cr-Mo-W Alloys. Journal of Metals, 35, (6), 37-43. Warrendale, 
Pennsylvania: The Minerals, Metals & Materials Society. TIC: 245100. 
154934 Turchi, P.E.A. 2001. Delivery of Property Diagram (Phase Fraction Versus 
Temperature) of Alloy 22 at Its Nominal Composition. Memorandum from P.E.A. 
Turchi (BSC) to RPC = 3, May 21, 2001, PROJ.05/01.051, with enclosure. 
ACC: MOL.20010522.0158. 
162974 Turchi, P.E.A. April 2003. Modeling of Stability and Aging of Candidate Alloys for 
Use In Waste Disposal Canisters. SN-LLNL-SCI-477-V1. 
ACC: MOL.20030626.0219. 

Aging and Phase Stability of Waste Package Outer Barrier 
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163109 Turek, I.; Kudrnovsk, J.; and Drchal, V. 2000. "Disordered Alloys and Their 
Surfaces: The Coherent Potential Approximation." Electronic Structure and Physical 
Properties of Solids, The Uses of the LMTO Method, Lectures of A Workshop held at 
Mont Saint Odile, France, October 2-5, 1998. Dreyss, H., ed. Pages 349-378. New 
York, New York: Springer-Verlag. TIC: 254254. 
161300 Vander Voort, G.F. 2000. Volume Fraction. Metallography, Principles and 
Practice. Pages 425-435. Materials Park, Ohio: ASM International. TIC: 254149. 
9.2 CODES, STANDARDS, REGULATIONS, AND PROCEDURES 
AP-2.22Q, Rev. 1, ICN 1. Classification Analyses and Maintenance of the Q-List. 
Washington, D.C.: U.S. Department of Energy, Office of Civilian Radioactive Waste 
Management. ACC: DOC.20040714.0002. 
AP-2.27Q, Rev. 1, ICN 4. Planning for Science Activities. Washington, D.C.: U.S. 
Department of Energy, Office of Civilian Radioactive Waste Management. 
ACC: DOC.20040610.0006. 
AP-SIII.10Q, Rev. 2, ICN 7. Models. Washington, D.C.: U.S. Department of Energy, 
Office of Civilian Radioactive Waste Management. ACC: DOC.20040920.0002. 
AP-SV.1Q, Rev. 1, ICN 1. Control of the Electronic Management of Information. 
Washington, D.C.: U.S. Department of Energy, Office of Civilian Radioactive Waste 
Management. ACC: DOC.20040308.0001. 
147465 ASTM B 575-99a. 1999. Standard Specification for Low-Carbon Nickel- 
Molybdenum-Chromium, Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon 
Nickel-Chromium-Molybdenum-Copper, Low-Carbon Nickel-Chromium- 
Molybdenum-Tantalum, and Low-Carbon Nickel-Chromium-Molybdenum-Tungsten 
Alloy Plate, Sheet, and Strip. West Conshohocken, Pennsylvania: American Society 
for Testing and Materials. TIC: 247534. 
105725 ASTM C 1174-97. 1998. Standard Practice for Prediction of the Long-Term 
Behavior of Materials, Including Waste Forms, Used in Engineered Barrier Systems 
(EBS) for Geological Disposal of High-Level Radioactive Waste. West 
Conshohocken, Pennsylvania: American Society for Testing and Materials. 
TIC: 246015. 
161301 ASTM E 562-95. Standard Test Method for Determining Volume Fraction by 
Systematic Manual Point Count. Philadelphia, Pennsylvania: American Society for 
Testing and Materials. TIC: 253834. 
LP-SI.11Q-BSC, Rev. 0, ICN 0. Software Management. Washington, D.C.: U.S. 
Department of Energy, Office of Civilian Radioactive Waste Management. 
ACC: DOC.20040225.0007. 

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ANL-EBS-MD-000002 REV 02 9-8 September 2004 
9.3 SOURCE DATA, LISTED BY DATA TRACKING NUMBER 
155299 LL010107712251.012. Transmission Electron Microscopy (TEM), Scanning Electron 
Microscopy (SEM), and Optical Microscopy of Aged Alloy C22 Base Metal 
Samples. Submittal date: 01/23/2001. 
163013 LL021009912251.003. Scanning Electron Microscope (SEM) Micrographs of Gas- 
Tungsten Arc-Welded Haynes Alloy 22 Samples (As-Welded) and Aged at Various 
Times and Temperatures Used for Area Fraction Measurements of Topologically 
Close-Packed (TCP) Phases. Submittal date: 01/21/2003. 
162012 LL030103612251.006. Haynes Weld Data for Alloy 22 Transformation Kinetics and 
Arrhenius Plots. Submittal date: 01/21/2003. 
163014 LL030103712251.007. Scanning Electron Microscope (SEM) Images of Base Metal 
Alloy 22 Samples Aged at Various Times and Temperatures Used for Area Fraction 
Measurements of Topologically Close-Packed (TCP) Phases. Submittal 
date: 01/23/2003. 
162011 LL030103812251.008. Base Metal Data for Alloy 22 Transformation Kinetics in the 
Matrix. Submittal date: 01/27/2003. 
162468 LL030104012251.010. Grain Boundary Data for Alloy 22 Transformation Kinetics. 
Submittal date: 03/10/2003. 
162009 LL030104212251.012. Scanning Electron Microscope (SEM) Images of Alloy 22 
Base Metal and Welds Aged at Various Times and Temperatures. Submittal date: 
01/22/2003. 
162691 LL030301612251.040. Transmission Electron Microscopy (TEM), Scanning Electon 
Microscopy (SEM), and Optical Microscopy Micrographs of Aged Alloy 22 Samples. 
Submittal date: 03/10/2003. 
163927 LL030607112251.021. Long-Range Ordering (LRO) of Alloy 22 Base Metal Aged 
at Various Times and Temperatures Using Vickers Microhardness Measurements. 
Submittal date: 06/20/2003. 
9.4 OUTPUT DATA, LISTED BY DATA TRACKING NUMBER 
LL030106312251.013. Property and Phase Kinetics Diagrams, Submittal 
date: 04/09/2003. 
LL030106412251.014. Validation of Computational Model, Submittal 
date: 04/04/2003. 
LL030606912251.020. Development Data from Alloy 22 Volume Fraction 
Measurements, Submittal date: 06/20/2003. 


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