OCRWM Corrective Action Program Page: 1 46 Condition ...

Assignment Information

Ownership Organization: Sandia National Lab

Responsible Organization: Sandia National Lab

CRRecordReport

Oversight Organization:

Oversight Lead:

OTM - Sci Division

Fish, Robert

27-Jun-09

4-46 Aro/

OCRWM Corrective Action Program

Condition Report

Record Report

MOL. 20 090630.0014

f#410 4-ctri

Page: 1

QA:QA

CR Num CR Level CR Type Step Entry Date Step Step Resp Step Owner

12799 C QARD 6/26/2009 2:32:22 PM Completed N/A N/A

Condition Information

CR Title: Unexpected Test Results - Heterogeneous Alloy 22 Oxide Thickness

Date Found: 25-Sep-08 CR Initiator: Brown, Neil

Time Found: 10:00 CR Initiating Org: Sandia National Lab

Involve Initiator? Yes

Condition Description:

Corroborative, non-Q, secondary ion mass spectrometry (SIMS) analysis of 5-year Alloy 22 corrosion coupons was performed according to TWP-WIS-MD-000025 and in support of TWP-WIS-MD-000027 and resulted in an unexpected test result. The analyzed coupons had been subjected to general corrosion

conditions and it was anticipated that the oxide thickness on a given sample would not exhibit significant spatial varietion. However, for three examined coupons (DWA132, DWB132, DWB134) it was determined that the region of the coupon covered by a PTFE washer during the corrosion test had a locally

thicker oxide than the remainder of the coupon. There was no evidence to suggest that any form of localized corrosion (e.g., pitting corrosion, crevice corrosion) had occurred under the washer. The area affected by the presence of the washer appears to be on the order of 3% of the total sample area. The small fraction of the sample area affected is insufficient to impact the calculated corrosion rates based on gravimetric analysis. Therefore, these results do not effect the SAR or the underlying models (ANL-EBS-MD-000003), but will require additional investigation.

Supplemental Information:

Routing Notes:

10/02/08 Danika Miller - This CR has been prescreened by a member of the CAP Staff using criteria Technical Information.

Trend Only? No

Requirement Involved? Yes

Requirement: SCI-PRO-002

Business Process:

Business Process ID:

Condition Information

27-Jun-09 Page: 2 OCRWM Corrective Action Program

Condition Report

Record Report slto, Step Resp

N/A

Step Owner

N/A

QA Review Type: No QA Review Required

Quality Assurance Rep (QAR):

Business Process Review Org:

CR Num CR Level CR Type Step Entry Date Step

12799 C QARD 6/26/2009 2:32:22 PM Completed

Assignment Information

Screening Information

CR Level: C

CST / MRC Conclusions:

10/06/08 Danika Miller - Significance Determination established at a Level C using criteria Technical Information.

Screening Information

Review Information

NRC Reportabilitv Review (e.g. Part 21 and 10CFR63.73b)

Potential NRC Reportable CR? No

NRC Reportable Discussion:

Validated NRC Reportable CR?

Self-Revealing Conditions

* Conditions identified outside of formal processes (such as Self Assessments) where

the event/consequence occurred prior to entry of the condition into CAP

Self-Revealing condition? No

10CFR835 - Radiological Protection Program (RPP) Review

Potential RPP issue? No

RPP Category:

RPP Discussion:

Validated RPP issue?

CRRecordReport

Date Submitted: 10/1/2008 Date Issued: 10/6/2008

27-Jun-09

kftri OCRWM Corrective Action Program

Condition Report

Record Report orel ktirl

Page: 3



10CFR851 - Worker Safety and Health Proaram (WSH131 Review

Potential WSHP issue? No Validated WSHP issue?

WSHP Category:

WSHP Discussion:

Step Resp Step Owner

N/A N/A

Occurrence Reporting and Processing System (ORPS1 Review

Potential ORPS issue? No Validated ORPS issue?

ORPS Criteria:

ORPS Significance:

ORPS Report ID:

ORPS Discussion:

NTS Reportable conditions only

NTS Report ID:

Review Information

Evaluation Information

Immediate/Interim Action Taken? No

Immediate/Interim Action Desc:

Previous Occurrence Review:

Extent of Condition:

CRRecordReport

27-Jun-09 Page: 4

41A9

Cause Analysis Information

Plan Information

Plan Due Date: 11/5/2008

Plan Completed Date: 10/30/2008

Original Est Comp Date: 3/20/2009

Current Est Comp Date: 6/18/2009

Date Completed:

Date Closed:

6/26/2009

6/26/2009

Actions Required? Yes

Corrective Action Plan Summary:

10/28/08 - B. Mitcheltree - The unexpected test result will have to be evaluated and analyzed, an action will be created for this.

CRRecordReport

Effectiveness Rev Required? No Effectiveness Rev Days


Condition Report

Record Report

CR Num CR Level

12799

CR Type

QARD

Step Entry Date Step

6/26/2009 2:32:22 PM Completed

Step Resp

N/A

Step Owner

N/A

Evaluation Information

Cause Analysis Information

Cause Analysis Type: N/A

Cause Analysis Results:

LL/GI Required?

Reason LL/GI Not Performed:

Cause Analysis Team Members

Team Member Name Team Member Organization

< NO CAUSE ANALYSIS TEAM MEMBERS IDENTIFIED FOR THIS CONDITION REPORT >

Cause Code(s):

A0B0000 - Cause not applicable or required

Event Code(s):

1MT - Measuring and Testing Equipment Program

2DT - Data

Review Information

Stmv Review Plan

Step Completion Date Person that performed review

10/29/2008 1:02:33 PM Brown, Neil

10/30/2008 11:43:27 Brown, Neil

AM

Oversee Implementation

Step Completion Date Person that performed review

6/26/2009 8:09:09 AM Mitcheltree, Wendy

27-Jun-09

or* kftri OCRWM Corrective Action Program

Condition Report

Record Report SAitei NE Amos

Page:

CR Num CR Level

12799

CR Type Step Entry Date

QARD 6/26/2009 2:32:22 PM

Step

Completed

Step Resp Step Owner

N/A N/A '

Discussed Plan with CR Initiator? Yes

Discussed Implementation with CR Initiator? Yes

Action Title

12799-001 Analyze residual oxide thickness

Discussion Results: 10/28/08 - B. Mitcheltree - The initiator agreed with the plan.

Discussion Results: 6/25/09, W. Mitcheltree- Spoke to initiator, he is fine with the resolution of

this CR.

Plan Information

Plan Approval Indicator and Comments, if any

• add oxide in two places

This plan is necessary and sufficient to address this CR. Analyses work is funded.

Neil Brown 10/30/08

Implementation Done Indicator and Comments, if any

6/25/09, W. Mitcheltree- There was one action for this CR, which was resoled as follows: As documented in the report, "Comparison of Oxide Thickness between 5 and 9.5 Year Alloy 22 Gravimetric Sample" dated June 24, 2009 the oxide

thicknesses for samples exposed for 5 and 9.5 year were examined to determine the likely causes and effects of the unexpected oxide heterogeneity. Based upon the work performed to date it is most likely that the increased oxide thickness is due to a deposition process rather than corrosion. This conclusion is based upon the fact that the oxides under the crevice contain much higher quantities of magnesium, silicon and organics than the boldly exposed surfaces. Alloy 22 does not contain these elements, so they likely came from corrosion of other materials tested in the same vessels as the Alloy 22. Also of note is that dark stained regions outside of the washer region contain similar surface product layers to that under the washer region, further suggesting that this is not a corrosion mechanism.

No

Yes

Yes

CRRecordReport

27-Jun-09

451 Page: 6

Step Resp

N/A

Step Owner

N/A

Neil Brown 6/26/09.

Review Information

CR Step History

Step Owner Step Resp Exit Date

Bonano, Evaristo Brown, Neil 10/1/2008

2 Staff Review CR 10/1/2008 Giacomini, Michael Miller, Danika 10/2/2008

Rev # EnteredStep Entry Date

1 Initiate CR 9/30/2008

CRRecordReport

CST Review CR Miller, Danika

Exit To Status

Staff Review CR

User that hit VO'

Brown, Neil

Milestone on Exit # of Days In Step

1


Condition Report

Record Report



Oversee Implementation (continued)

Step Completion Date Person that performed review Implementation Done Indicator and Comments, if any

The oxides under the washer region are considerably thicker for the 9.5 year samples

than for the 5 year samples. This observation further supports the conclusion that

this is not a corrosion mechanism as the corrosion rates for the 9.5 year samples are

lower than for the 5 year samples. Since there is no evidence that this is a corrosion

mechanism, a likely explanation for the thicker regions in the 9.5 year samples is that

the concentrations of the deposition products were increasing with time in the test

vessels. Considering that the corrosion of other materials in the vessels is occurring

as a function of time, it is reasonable that this would result in increasing concentration

of these constituents. Furthermore, increased organics both in terms of quantity and

prevalence were also observed in CR 12868.

Therefore, based upon the available information, the unexpected test condition does

not have an impact on the corrosion rates or mechanism used in the Alloy 22

corrosion models. The action for this CR has been completed and this CR should

therefore be closed.

Sum/ Verify Irnol

Step Completion Date Person that performed review CR Verification Indicator / Comments

6/26/2009 2:08:30 PM Brown, Neil Yes I concur that this CR should be closed. All available evidence indicates that the

unexpected results are due to environmental deposition and not corrosion.

10/6/2008 Plan CR

10/28/2008 Supv Review Plan

Plan CR

Supv Review Plan

Oversee Implementation

Supv Verify Impl

CST Close CR

Miller, Danika

Mitcheltree, Brian

Brown, Neil

Mitcheltree, Brian

Brown, Neil

Mitcheltree, Wendy

Brown, Neil

CR ISSUED 10/6/2008 12:15:02 PM

PLAN COMPLETED 10/30/2008 11:43:27 AM

CAs COMPLETED 6/26/2009 8:09:09 AM

N/A

10/29/2008

10/29/2008

10/30/2008

6/26/2009

6/26/2009

4

22

1

239

0

6/26/2009 Completed Miller, Danika CR CLOSED 6/26/2009 2:32:22 PM

0

Mitcheltree, Brian

Brown, Neil

Bonano, Evaristo

Bonano, Evaristo

10/30/2008 Bonano, Evaristo

6/26/2009

6/26/2009

6/26/2009

Bonano, Evaristo

Pesek, John

N/A

CR Attachments

Filename

CR 12799 Closure Checklist.doc

Size Date

85 kb

27-Jun-09

or* *ri OCRWM Corrective Action Program

Condition Report

Record Report orAti ItY

Page: 7

CR Num CR Level

12799

CR Type Step Entry Date Step

QARD 6/26/2009 2:32:22 PM Completed Step Resp

N/A Step Owner

N/A

10/2/2008 CST Review CR

10/6/2008

Supv Review Plan 10/28/2008

_Q. Plan CR -10/29/2008

Supv Review Plan 10/29/2008

8 Oversee Implementation

Supv Verify Imp!

10 CST Close CR

11 Completed

Giacomini, Michael Miller, Danika

Bonano, Evaristo

Bonano, Evaristo

Mitcheltree, Brian

Brown, Neil

Mitcheltree, Wendy

Brown, Neil

Miller, Danika

N/A

Plan CR

CR Step History

CR Attachments

CRRecordReport

27-Jun-09 Page: 8

04* Ativi


Condition Report

Record Report

Corrective Action Report

Step Owner

N/A

Step Resp

N/A CR Num Action Num Step Entry Date Step

12799 12799-001 6/26/2009 8:08:13 Completed

Action Details

Action Number: 12799-001 Current Due Date: 6/11/2009

Original Due Date: 3/13/2009

Accepting Org: Sandia National Lab Bonano, Evaristo

Assigned To Org: Sandia National Lab Bonano, Evaristo

Action Title: Analyze residual oxide thickness

Date Completed: 6/25/2009 Date Closed: 6/26/2009

Action Description:

10/28/08 - B. Mitcheltree - Analyze/evaluate residual oxide thickness for the boldly exposed surfaces and under the crevice region for time-frame other than 5-year exposures. This information will be used to determine if the unexpected heterogenetity under the crevice former increases with time and at what rate. This information will be used to either document no impact or additional actions will be required for this CR.

The objective evidence will be the result of the analyses/evaluation or justification why this was not performed.

Action Taken:

6/25/09- W. Mitcheltree- As documented in the attached report, "Comparison of Oxide Thickness between 5 and 9.5 Year Alloy 22 Gravimetric Samples", dated June 24, 2009 the oxide thicknesses for samples exposed for 5 and 9.5 years were examined to determine the likely causes and effects of the unexpected oxide heterogeneity. Based upon the work performed to date it is most likely that the increased oxide thickness is due to a deposition process rather than corrosion. This conclusion is based upon the fact that the oxides under the crevice contain much higher quantities of magnesium, silicon and organics than the boldly exposed surfaces. Alloy 22 does not contain these elements, so they likely came from corrosion of other materials tested in the same vessels as the Alloy 22. Also of note is that dark stained regions outside of the washer region contain similar surface product layers to that under the washer region, further suggesting that this is not a corrosion mechanism.

The oxides under the washer region are considerably thicker for the 9.5 year samples than for the 5 year samples. This observation further supports the conclusion that this is not a corrosion mechanism as the corrosion rates for the 9.5 year samples are lower than for the 5 year samples. Since there is no evidence that this is a corrosion mechanism, a likely explanation for the thicker regions in the 9.5 year samples is that the concentrations of the deposition

products were increasing with time in the test vessels. Considering that the corrosion of other materials in the vessels is occurring as a function of time, it is reasonable that this would result in increasing concentration of these constituents. Furthermore, increased organics both in terms of quantity and prevalence were also observed in CR 12868.

CRRecordReport

Proposed Due Date

4/10/2009 6/11/2009

Step

Completed Completed

Action Attachments

Filename

Washer Report Ver3.pdf

Size Date

679 kb

27-Jun-09 Pak OCRWM Corrective Action Program

Condition Report

Record Report

Corrective Action Report

f* euø

Page: 9

CR Num

12799 Action Num

12799-001 Step Entry Date Step

6/26/2009 8:08:13 Completed Step Resp

N/A Step Owner

N/A

Therefore, based upon the available information, the unexpected test condition does not have an impact on the corrosion rates or mechanism used in the Alloy 22 corrosion models. This CR action should therefore be closed.

Routing Notes:

Action Details

Action Adjustments

Adjustment Num Adjustment Title

12799-001-001 Due Date Adjustment 12799-001-002 Due Date Adjustment

Action Adjustments

Action Step History

Rev # EnteredStep

1 Plan Action

2 Perform Action

3 Plan Action

4 Perform 'Action

5 Completed

Step Owner

Bonano, Evaristo

Bonano, Evaristo

10/29/2008

10/29/2008 Bonano, Evaristo

6/26/2009 N/A

Step Resp

Mitcheltree, Brian

Mitcheltree, Brian

Mitcheltree, Brian

Mitcheltree, Wendy

N/A

Exit Date Exit To Status

10/28/2008 Perform Action

10/29/2008 Plan Action

10/29/2008 Perform Action

6/26/2009 Completed

User that hit GO'

Mitcheltree, Brian

M itch eltree, Brian

M itch eltree, Brian

M itch eltree, Wendy

# of Days in Step

0

240

N/A

Entry Date

10/28/2008

10/28/2008

Bonano, Evaristo

Action Step History

Action Attachments

CRRecordReport

Step Resp Exit Date

Brown, Neil 1/23/2009

3 Bonano, Evaristo 1/26/2009

Exit To Status

Accept Act

Adjustment

Completed

N/A

User that hit 'GO # of Days in Step

Brown, Neil 0

Bonano, Evaristo

N/A

Rev # EnteredStep Entry Date Step Owner

1 Request Act 1/23/2009 Bona no, Evaristo Adjustment

2 Accept Act 1/23/2009 Bonano, Evaristo Adjustment

3 Completed 1/26/2009 N/A

Action Adjustment Step History

CRRecordReport

Step Owner

N/A

27-Jun-09

CR Num

12799


Condition Report

Record Report

CA Adjustment Report

or* Nfitvi

Page: 10

Action Num

12799-001 Step Resp

N/A

Action Adj Num Step Entry Date Step

12799-001-001 1/26/2009 1:41:02 Completed

Action Adjustment Details

Adjustment Number: 12799-001-001

Requested Due Date: 4/10/2009 Date Request Submitted: 1/23/2009 Date Closed: 1/26/2009

Adjustment Title: Due Date Adjustment

Reason for Adjustment:

As a result of many RAls from the NRC, DOE and the Lead Laboratory have agreed that resources planned to address this CR will be moved to RAls. Neil Brown 1/23/09

Adjustment Response:

Tito Bonano - 01/26/09 I approve the extensions.

Routing Notes:



User that hit 'GO'

Mitcheltree, Brian

# of Days in Step

0

Mon, Kevin

Completed 4/28/2009 N/A N/A 3 N/A

Step Owner

N/A

27-Jun-09

CR Num

12799

olitV kli„V


Condition Report

Record Report

CA Adjustment Report

oat %fete,

Page: 11

Action Num

12799-001 Step Resp

N/A

Action Adj Num Step Entry Date Step

12799-001-002 4/28/2009 3:52:39 Completed


Adjustment Number: 12799-001-002

Requested Due Date: 6/11/2009

Adjustment Title: Due Date Adjustment

Reason for Adjustment: •

4/28/09 - B. Mitcheltree - Budget cuts, and RAI resource usage.

Adjustment Response:

04/28/2009 Kevin Mon adjustment accepted for Neil Brown

Routing Notes:

Date Request Submitted: 4/28/2009 Date Closed: 4/28/2009



EnteredStep

Request Act Adjustment

Accept Act 4/28/2009

Adjustment

Step Owner Step Resp

Bonano, Evaristo Mitcheltree, Brian

Bonano, Evaristo Mon, Kevin

Exit Date Exit To Status

4/28/2009 Accept Act

Adjustment

Completed

Rev #

1

Entry Date

4/28/2009

4/28/2009


CRRecordReport

SNL Conducted by: Wendy Mitcheltree CR Number: 12799 CR Level: C Resp. Org:

CR Closure Verification Checklist

Personal or sensitive information should not be included in condition reports.

Documentation should provide traceable, verifiable, objective evidence that will demonstrate that each action was completed as stated

in the plan within the CR record. It should be in sufficient detail that uninvolved third-party reviewers can understand the reasons

behind the decisions made, analysis, extent of condition, and corrective actions.

Applicable Yes/No Attribute Comments

To Level(s) NA ,

Miscellaneous CR Fields

If Involve Initiator field is "Yes, does the Disc Plan w/Init and/or the A-D YES

Disc Impl w/lnit field have appropriate wording to affirm?

If the LUG! Required field is "Yes," has a lessons learned been N/A

submitted?

CAQs

Requirement Involved is "Yes' A-C YES

If the Requirement Involved field is "Yes, is the Requirement field YES

completed with something other than TBD?

Trend Onl if a ..licable

Does CR clearly state what was corrected and/or why no further C-D N/A

action is required

Extent of Condition (EoC)

Is documented in the CR A-B N/A

The bounding methodology is appropriate and documented in the N/A

CR

A. . arent or Root Cause

Is clearly stated A-B N/A

Identified Cause(s) are supported by investigative findings N/A 1

Previous Occurrence

Is documented in the CR A-B N/A

Identified similar CRs N/A

1 of 2

12/15/08

Applicable Yes/No Attribute Comments

To Level(s) NA

Corrective Actions

Identify Actions to preclude recurrence A N/A

Address the Cause(s) identified or there was adequate explanation A-B N/A

of why no action was necessary

Is clear enough to identify that the corrective action(s) was A-D YES

completed satisfactorily

Support the correction of the condition identified in the CR YES

If actions were not completed as stated, an explanation was N/A

provided

If no action will be taken, rationale is provided N/A

Documentation

Additional documentation, as referenced, has been attached or its A-D YES

location has been identified

Closing one CR to an existing CR, if applicable

The issue documented within the new CR is already addressed A-D N/A

within the existing CR

The newer CR is closed to an older CR N/A

The higher significance level CRs is not closing to a lower N/A

significance level CR

Closing to another Business Process, if applicable,

The business process(es) is a controlled process, managed by N/A

procedure, periodically assessed, and tracked/trended.

When utilizing other business processes to track the completion of N/A

the action(s):

1) There is a clear statement documents the process that will be N/A

utilized to track action(s),

2) There is a cross-reference to a tracking number(s) within that N/A

process, and

3) There is a clear statement how the process is documented and N/A

periodically assessed

Non -Valid CR if a. • ',cable

Documentation clearly affirms that the original issue was not valid N/A N/A

2 of 2

12/15/08

Comparison of Oxide Thickness between 5 and 9.5 Year Alloy 22 Gravimetric Samples K.R. Zavadil & J.A. Ohlhausen, June 24, 2009

Goal of Analysis The goal of the work described in this report was to determine whether a longer period of corrosion test exposure, 9.5 years vs. 5 years, produced detectable differences in remnant oxide and exposure product layers on Alloy 22 gravimetric samples. Specific emphasis was placed on an annular region surrounding the mounting bore hole of these test coupons originally covered by a Teflon washer. This region of interest was previously , explored for 5 year samples and results were summarized Oxide Thickness Measurements for C22 Weight Loss Samples:

Coupons DWA132 and DWB132 (November 19, 2008). Despite the presence of the Teflon washer covering this region of the surface, micron deep grooves produced by a directional 600 grit polish on the coupon front face allowed for electrolyte penetration and resulting surface chemical processes to take place. Acetone and HC1 cleaned coupons typically show dark staining in this area of the sample, indicating that residual corrosion and exposure related products remain and are factored into the overall gravimetric analysis used to determine a corrosion rate. The work described within this report attempts to evaluate the extent to which gravimetric estimates might be influenced by exposure time.

Approach Surface characterization was conducted on five weight loss, long term corrosion test C22 coupons — two immersed for 5 years and three immersed for 9.5 years in a simulated concentrated water (SCW) electrolyte at 90°C. Analysis was conducted using a combination of time-of-flight secondary ion mass spectrometery (ToF-SIMS) and scanning electron microscopy (SEM) with energy dispersive x-ray analysis. SIMS sputtering was conducted with the incident ion parallel to the 600 grit polishing striations on the samples to minimize shadowing effects in the depth profile. SEM analysis was typically used to examine the SIMS sputter crater and the region around the craters within the washer region to determine the morphological origin of the depth profile data. A minimum of seven sites were analyzed on, each coupon with three located within the region of the washer and four on the openly exposed surface of the coupon. The oxide on a mechanically polished (30 nm alumina) C22 disk that was cleaned in acetone followed by a 12 minute immersion in 1.8 M HC1 served as a calibrant for sputtering rate. Several focused ion beam cross-section samples were prepared and imaged using transmission electron microscopy. The lattice spacing in single crystal silicon was used as a calibrant for the TEM measurements. All of the depth profiles for the weight loss coupons within this report were generated using the same energy and flux of Cs ÷ ions as for the reference C22 disk.

Results Table 1 provides a summary of the description, sputter times and calculated oxide thickness for each of the sites analyzed for the sample set under consideration. This data is further condensed into a set of average oxide thickness values as a function of exposure time and analysis site in Table 2 and Figure 1 to allow for easier comparison. The light and dark site designations in these tables 'make reference to the general optical appearance of the site and, in select cases, represent remnant surface product not removed during the cleaning process. We consider the optically light regions as the baseline for comparisons within this study. The data of Tables 1 and 2 demonstrate that the surface oxide is on average twice as thick within these light regions for 9.5

Comparison of Oxide Thickness between 5 and 9.5 Year Alloy 22 Gravimetric Samples page 2of 8

versus 5 years of exposure. The optically dark regions generally possess thicker surface oxide

Table 1: Comparison of Oxide Thickness Measurements of Select Sites on

Immersed SCW 90°C C22 Weight Loss Coupons

Sample Time (yr) Site Description Sputter Time (s) Thickness (nm) *

DWA132 5 A light 102 9

B light 93 8

C dark 198 17

D dark 203 17

E washer > 3240 273

F washer >4817 506

G washer 656 55

DWB132 5 A light 58 5

B dark 145 12

C dark 167 14

D dark 118 10

E washer 511 43 ,

F washer 331 28

G washer 580 49

, DWB139 9.5 A washer 5633 474

B washer 2520 212

C light 192 16

D light 174 15

E dark >2072 >174

F dark >4720 >397

G dark >4785 >403

H washer 212 18

DWA140 9.5 A light 240 20

B light 220 18

C dark 227 19

D dark 257 22

E washer 10444 880

F washer 5155 434

G washer 10049 846

DWB140 9.5 A washer 2643 223

B washer >4902 >413

C washer >2200 >185

D •dark >2584 >218

E light 216 18

F light 228 19

G light 185 16

with respect to a mechanically polished, HC1 etched C22 disk stored in

N2 and demonstrated to have a 1.6 nm thick oxide via TEM.

layers when compared to light regions for a given exposure time. The 9.5 year DWA140 sites C

5 300

.c 250

•

200


and D appear to be exceptions to this trend and may reflect a degree of arbitrariness to this visual

classification (light, dark) of the sample surface. Note that sputter times for optically dark sites

were occasionally not sufficient in duration to completely breakthrough the surface oxide layer

across the full analysis site. The cumulative ion yield images generated over the course of the

profile show that these incomplete sampled sites are comprised of two components - regions of

thinner and significantly thicker

surface oxide. The resulting depth Table 2: Comparison of Average Oxide Thickness profiles represent a spatial convolution for Various Sites on Alloy 22 Coupons as a of these two components. The

Function of Immersion SCW 90°C Time thickness values for these sites listed Time (yr) Description Thickness (nm) * in Table 1 reflect the minimum values

5 light 7 for the thickest component. The

dark 14 average oxide thickness value

washer 180 displayed in Table 2 and Figure 1

9.5 light 17 should also be thought of as a

dark 204 minimum thickness for the thickest

washer 509 component of a spatially

heterogeneous oxide. Spatially

heterogeneous oxides are also

observed for the washer regions on

500

these coupons. Comparison of the

thickness of these dark regions 450

between the two exposure times shows 400

that the oxide is more likely to be — 350 '—

significantly thicker for the longer

exposure time.

The oxide layer appears to be thicker I — for the longer exposure period samples 150 -

within the washer region. The 5 year loo samples exhibit a range of thickness

50

values from 30 to 50 nm with several

sites in excess of 300 nm. The 9.5 year 5 war 5 year 5 year 9.5 year 9.5 yea, 9 5 year

samples also exhibit large variation light dark washer light dark washer

with one 18 nm thick site (DWA139 Exposure Time and Coupon Site

site H) and the remainder ranging Figure 1. Average oxide thickness as a function of from 200 to 900 nm. This variation in Alloy 22 SCW 90°C immersion exposure time and thickness is a function of where within site (*the average minimum thickness for the the washer region a site is selected for thickest component for a spatially heterogeneous sampling, as both optical and oxide). secondary electron images of these

regions show areas of thick and thin surface deposits. SEM images were used to confirm that the

thin oxide observed for DWA139 site H was the result of sampling a thinner deposit region.

Despite the limited sampling conducted within this study, the measurements suggest a thicker

surface layer remains after cleaning for the longer exposure time of 9.5 year. All of the washer

sites with the thicker surface layers (> 60 nm) show clear evidence of the presence of two surface


layer components, as discussed previously for the optically dark sites, with a large difference in

thickness. 1

I 3.5E+04 1 6E+03 3(0.04 4.0E+03

i DWB139 Site A - Ni (Y1) b DVVB139 Site A -Ni (y1) .

I a _MO (y1) 1.4E+03 3.5E+03 3.0E+04 - 3.0E+04 - -Si (y1)

I

. - Cr0 (y1)

- Ca) (y2)

_ Moo6,02)(y2) 1.2E+03 2.5E+041 -

.•

7

- 190 (y1)

- C2H (y1) • 3 0E+433

I 113E+03

,i. Mg0 (y2)

I

Z. •

T„ 2.0E+04 - ,, ' '• ' 1 • 1

,a" 2 0E+04 - ;

.'

: - 0 (.12)

• 2_5E+03

i,

I 5 I

_ . r

I 8 0E+02 • -

' -2 0E+03 , .E.

I f, 1.5E-iO4 1 g 1.5E+04 -

6.0E+02 - I . 1.5E+03

I

14, 5 1 0E+04 i 1 0E+04 - 1111I,•illial . 4 0E402

, '44111\11111iiiiii,,_ , • 1 0E403

1

I 1

5.0E+03 • ' 1 ̀s-

i ____„_ -. ---M4(...e.,,

2 0E+02 5.0E+03 -71111

.k. 1111111 e,„*„......„..._

I 0 1030 2C00 3000 4110 5C00 6000 7000 8000 9030 00E+03 - .... -.1.-----4-- . 0 0E+00

I 3.0E+04

Sputter Time (e) Spinet Time )s1

2.0E+03 1.0E+05 Ci 1" 2" "CI 4" 61" 6" 7" 61" "3 2 0E+433

I c . DWB139 Site C -Ni (y1)

- Ni0 (y1) 1.3E+03 9 0E404 d DVVB139 Site C

-Ni (y1)

- CI (y1) 1.8E+03

a 2.5E+04 - - 1 e0 (y1) - Si (y1)

I -Cr0 (y1) 1.6E+03 80E.04 r\\ _ TO (y1) 1_6E+03

I - C°° (Y2) 1.4E+03 70E4434 1 4E+03

-- ONIC29HD°:)(Y1) 1 2E+03

I

2, 7

.4 2_0E+04 II MOO (y2)

- 0 (y2) 1.2E+03 4, 6.0E+04

2

i

\ 1.5E404 1.0E+03 2 50E404 I 1.0E+03

I . g

* ,J. ,

900.02 2 4.0E+04 I , 8.0E+02

I ' 1.0E+04

1 6.0E+02 305.434 ; .',. 606.02 1 • I

. ' Ck ■ 4.0E+ . 02 20E4434 , ., , 4.0E+02 ... ..., 5.0E+03 i \A

2.0E+02 1.0E+04

0.0E+00 , ---------- ..,.-'-`-:-"4:4.-:i1-''''''''''''''''''' •••""*"'•• 0 0E+00 0091.03 ' '. ' ------rs= . --L"----- "-'-' -• 0.0E+00

0 203 400 600 600 1000 0 200 4433 600 803 1(03

Simnel- Time (s) Sperm, Time 151

2.5E+04 1 0E+03 6.0E+04 3.0E4413

e DWB139 Site G -rui (y1) f DWB139 Site G -Ni (y1)

Nic) ( y i) -9 0E+02 -CI (yl)

- Fe0 (y1) 513E+04 - -51 (Y 1 ) - 2.5E+133 20E+04 - A - 8.0E+02 • - -310 (y1) - CIO (y1) _ .

- Co0 (y2) . 0E+02 ,1110441/011,Soilli\slisiitt C2H (y1)

7

. . Mo0 (y2) 4 0E+04 - - . • . . MgO (y2) . 2.0E+03

.., 1.5E+04 - • --0 (y2) - 6.0E+02 2.: - 0 (y2)

f . 5.0E+02 (I• 3.0E+04 - .

- 1.5E403 . . ' .

'

1

.

2 10E 4 0E+ 404 - '

•

5.0E403 - k '

.. • ._ .•

. : . .. : : ,. .

. . .. . , .

• 02 2

- 3 0E+02

- 2.0E+02

• .

2.0E+04 -

1.0E404

4. ,Iii

ir min 0 i

• ,

- 5.0E+02

10E+02

0 0E+03 ODE -OWa0E400 0 0E+00

I

0 1000 ZOO 100 4000 5003 6000

Swale, Time IsI

1000 211033300 41300 51:0) 6000

Swale, Time lel

Figure 2. Comparison of ToF-SIMS depth profiles for three sites on sample

DWB139: a,b) unintended crevice site A, c,d) optically light open surface site C, I,

and e,f) optically dark open surface site G. The yl and y2 designations in the plot

legends indicate which ordinate axis a given ion intensity is plotted against (1 -

primary or left, 2 - secondary or right).


The composition of the oxide layer within the washer region is unique when compared to the regions of the coupon that had been effectively cleaned in advance of the material loss measurements. Figure 2 shows representative depth profiles for three sites on DWA139, including: 1) washer site A, 2) optically light site C, and 3) optically dark site G. Two plots are shown for each site that display the primary alloy constituents (as metal oxide ions) and select environmental constituents including Cl, Si (as a silicate), Mg as the Mg0 - ion and C21-1- as an indicator of carbonaceous content in the surface layer. Readily seen in Fig. 2 is the fact that washer region contains high relative levels of Cl, Si, Mg and organic species distributed through the oxide surface layer. These results are contrasted with the thinner oxide at site C (open surface, well cleaned) that show a hydrocarbon terminated oxide surface with substantially lower relative levels of Mg, Cl and Si in the outer section (near electrolyte) of the oxide surface film. Site G (along with sites E & F — not shown) is a special case where staining and residual product layers are evident on the surface as viewed with optical and electron microscopy. Note that the 0 profile exhibits a characteristic hybrid signature comprised of a narrow time period (depth) of intense secondary ion yield followed by an extended period of lower yield. This signature is a convolution of the sputtering of a thin oxide between islands of thicker product layer. Si, Cl and Mg are distributed through the product islands along with a significant amount of carbonaceous species. The fact that similar surface product layers are observed outside of the unintended washer region suggests that the basic compositional nature of the corroded surface product layer that formed underneath the washer may not be significantly different than that which forms out on the open surface. Microstructural or subtle compositional aspects of the film may determine the extent to which it is removed during the cleaning process.

Figure 3. Secondary electron (SE) image of a corner of site E on DWB140. X-ray fluorescence spectra are shown for regions of interest outside and inside the sputter area. Elemental maps for Mg and Si show environmental constituent distribution.

Figure 4. SEM image of SIMS analysis site E

on DWA132


These electrolyte and environmental constituents are also represented in the electron microscopic

data generated for the washer sites. Figure 3 shows regional energy dispersive x-ray analysis spectra along with select images of the corner of the sputter crater at DWB140 site E to highlight

the most probable coupling between morphology and composition of the sputter site based on

proximity. The regions of low secondary electron (SE) emission in Fig. 3 correspond to regions of high x-ray fluorescence from Si, Mg, 0 and C (the latter two not shown). Fluorescence

intensity for Mg and Si correlates with the 600 grit polishing striations showing that the surface product lines the grooves of these original mechanical features; forming channels for electrolyte

entry underneath the Teflon washer. Fluorescence intensity from Si and Mg is largely absent within the sputter crater except along several deeper grooves due to sputter removal highlighting

the variation in oxide layer thickness encountered during this analysis. A comparison of full fluorescence spectra for regions outside and inside the sputter region show that the unsputtered

surface layers contain elevated levels of all of the environmental constituents observed in the

SEWS measurements.

The thickness values reported in Table 1 represent maximum estimates of a morphologically variable surface layer. Measurements appear reasonably accurate for the well-cleaned open surface sites based on the profile shapes and comparisons of topology effects on control C22

samples. Estimates become significantly more problematic when analyzing sites with readily detectable microstructure variations observed by SEM within the washer region of these

samples. Better measurements would be achieved by accounting for the area fractions occupied by the thinner and thicker surface layers within a given analysis site. Such an analysis assumes that the surface layer can be approximated by two components: one thin and one thick. Such an

assumption seems reasonable based on the SEM data of Figure 4 acquired within the washer

region of sample DWA132 surrounding site E. The sputter crater is clearly visible

as the bright 300 x 300 [tm 2 feature, with

SIMS data acquired from the center 50 x

50 g.im2 region of this site. Several levels of product layer morphology variation are evident in the surrounding area — presumed to represent the original

properties of Site E prior to sputtering. Morphological variation includes vertical banding and infilling of polishing grooves, creating the possibility for the presence of

two levels of surface product. Figure 5a-b show the cumulative ion maps (integrated

over the full period of sputtering) for 58Ni"

and C2I-1- . These maps show a general

correlation between regions of high and

low yield for these secondary ions. SIMS profiling is always conducted with the sputter beam aligned parallel to the directional polishing striations on the surface and thicker surface layers

tend to occupy the groove bottoms (see Fig. 4). A complementary mask was generated to define

these two regions as shown in the binary image of Figure Sc. This mask was then used to


recreate complementary depth profiles for these two regions. Note that the binary mask allows for a simple computation of the area fraction for these two regions. The results of this analysis are shown in Figure 6a-f. The result of this analysis is a reasonable separation of an apparent thinner and thicker surface oxide. The thin oxide region shows a narrow peak in ion yield with a

width approaching values observed for the efficiently cleaned open surface of this sample. The

thick oxide region shows a broader distribution of 0 ion yield to substantially longer sputter times (depth). Examination of the profiles for the environmental constituents shows that Si, Mg

and carbonaceous constituents track with thickness showing a broader distribution through the thicker region. The Cl response is more intense for the thicker region but shows broad

distribution in the thinner region. Of note is the fact that the 0 ion yield does not fully decay to zero indicating only partial separation of thin and thick surface layers.

_ . Figure 5. Cumulative secondary ion images for 58Ni" (a) and C21-1- (b) for DWA132

site E and the mask generated from these images (c)

These results were sufficiently encouraging to apply this technique to the full set of washer sites

analyzed in this report. Significant problems were encountered that more frequently produced a poor quality separation between thin and thick regions for this sample set. These depth profiles are run under conditions that optimize mass resolution as opposed to spatial resolution and

improved spatial resolution may aid in determining the analysis area fraction of each component. An additional complication was found in clearly identifying the appropriate constituent secondary ions upon which to base the mask. Additional work would be necessary to refine this

analysis process so as to produce a more consistent and reliable result.

Conclusions A measurable increase in the remnant surface oxide thickness is observed with SCW 90°C immersion time (5 vs. 9.5 year) for chemically cleaned Alloy 22 coupons. The washer region of

these samples, along with select optically dark sites on the coupon front face, contains an oxide surface product layer that is spatially heterogeneous. Results show that the minimum thickness of

the thickest regions of this surface layer can be in excess of 0.5 im thick. Thicker product layers are observed with longer exposure time in this washer region of the coupons. A possible method

for establishing an area weighted estimate for these thickest product layers is demonstrated.

6E4433 35E.04

1 4E403 30E-+04

1 2E403 2 5E404

1 0E403

2 0E404

800.02 I

g 1.5E.04

600.02 -

1 0E404 400402

200.02 500.03

- Ni (y1)

- NO (y1)

- FeO (y1)

-CIO (y1)

- Co° (y2)

- -MoO (y2)

-0 (y2)

3.0E404

2.5E404

2.0E404

; 1.5E+04

10E+04

5.0E403

1.8E400

1.6E400

1.4E+03

1 2040)

1.0E+00

- 0E431

6 0E-01

0 500 1000 1500 2000 2500 3000 3503 41315)

Spinet Time Is)

2.0E400

1.8E+00

1 6E+00

1 4E+00

1 2E+00

42 1 0E+00

2

SUE-U1

6.0E-01

4.0E-01

2 GE-01

000.00

-Ni (y1)

- 510 (y1)

FeO (y1)

- Cr0 (y1)

- Ce0 (y2)

Me0 (y2)

0 (y2)

- NI (y1)

- CI (y1)

- Si (y1)

- 110 (y1)

- C2H (y1)

- MgO (y2)

- 0 (y2)

1.4E-01

1.2E-01

1.0E-01

8.0E-02

6 0E-02

4.0E-02

2.0E-02

0.0E.00

0 3500 4000 1000 1500 2CCIO 2500 3300 0 500 2503 3000 30034025

DWA132 Site E - NI (y1)

- CI (y1)

- Si (y1)

-1)0 (y1)

- C2H (y1)

- Mg0 (y2)

- 0 (y2)

250.04

206.03

5 0E+02

1 5E+03

1 0E403


0.0E.02 0.0E+00

0 500 1000 15D3 2030 • 2500 3115) 3500 4000

Slimier Time 04

0.0E400 I 0.004C0

0 5133 1000 1500 2000 2500 3000 3500 4(03

Spieler lime is)

- Ni (y1)

100(y1)

- FeO (y1)

- Cr° (y1)

- Co0 (y2)

Me0 (y2)

0(y2)

1.2E-01 1.8E-o3

1.664o3

0E-01

1 4E+00

-Ni (y1)

- CI (y1)

- Si (y1)

- (y1)

- C2H (y1)

- MgO (y2)

-0 (y2)

1.2E-01

1 0E-01

El 0E-02

6.0E-02

4.0E-02

2.0E-G2

a 0E.00

C DWA132 Site E, thin oxide

800-02 1 2E4CC

100.03

600-02 :1

13E-01

4 0E-02 6.0E-0

4 CIE-01 VIILINIMILL 1,. I 4 0E-01

2 CIE-02

2 0E-01 2.0E-01

0.0E400 , ( ---"4`.111719111r111411.1 0 0E+00 00E+00

0 500 1000 1500 2000 2500 3000 3500 4000

Sputter Time (s)

I 0E431 2.5E+00

9.0E-02

0E-02 20E400

7 0E-02

SUE-U) 44, 1 5E+00

5 0E-132

400-02 1 0E-400

3.0E-02

20E-02 5.0E-01

1 0E-02

0 0E+00 0.0E400

503 1000 1500 2000

Sputter Thee Is) Swim Time is)

Figure 6. SIMS profiles for DWA132 site E: a,b) full analysis area, c,d) mask

separated region of high ion yield - thin oxide, and e,1) mask separated region of low

ion yield - thick oxide. Ion intensity is normalized to pixel number for c-f.

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