ML11105A160
ML11105A160 | |
Person / Time | |
---|---|
Site: | Three Mile Island ![]() |
Issue date: | 04/05/2011 |
From: | Johnson E Exelon Nuclear |
To: | Office of Nuclear Reactor Regulation |
References | |
TMI-11-055 204, Rev 0 | |
Download: ML11105A160 (62) | |
Text
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Revision 0 Page I of 31 2010 Augmented Reactor Building (IWL) In-Service Inspection (Following the IR18 Steam Generator Replacement)
Evan Johnscm Author Hward T. Hill, PE& (CA Cert C22265)Co-Author Design Verification Required?Sat Bennett Mana Section Manager Date Date Qlyes 0No/Date 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Revision 0 Page 1 of 31 2010 Augmented Reactor Building (IWL) In-Service Inspection (Following the I R18 Steam Generator Replacement)
Evan Johnson Author Date Howard T. Hill, P.E. (CA Cert. C22265)Co-Author Hien Do Reviewer Design Verification Required?Pat Bennett Section Manager Date Date[-]Yes ZNo Date 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Table of Contents Revision 0 Page 2 of 31 Table of Contents 1. PURPOSE, INTRODUCTION AND BACKGROUND 4 1.1 PURPOSE 4 1.2 BACKGROUND INFORMATION 4 1.2.1 STEAM GENERATOR REPLACEMENT PROJECT CONTAINMENT OPENING 5 1.3 SECTION INTRODUCTION 5 2.
SUMMARY
OF WORK PERFORMED AND INSPECTION RESULTS 6 2.1 WORK PERFORMED 6 2.1.1 POST-TENSIONING SYSTEM TESTING AND EXAMINATION 6 2.1.2 CONTAINMENT SURFACE EXAMINATION 7 2.1.3 EXTENT OF CONDITION TESTING AND ADDITIONAL TENDON INSPECTIONS 8 2.2 INSPECTION RESULTS 8 2.2.1 POST-TENSIONING SYSTEM 8 2.2.2 CONTAINMENT SURFACE 9 3. POST-TENSIONING SYSTEM TESTS AND EXAMINATIONS 10 3.1 TENDON END ANCHORAGE FORCES 11 3.1.1 INDIVIDUAL TENDON FORCES 11 Table 3-1 Tendon End Anchorage Forces 12 3.1.2 GROUP MEAN FORCES 12 3.2 TENDON ELONGATIONS AND RE-TENSIONING 13 3.2.1 ELONGATIONS 13 Table 3-2 Tendon Stressing Elongation Data 15 3.2.2 RE-TENSIONING 16 Table 3-3 Tendon Re-Tensioning Data 16 3.3 END ANCHORAGE CONDITION 16 3.3.1 CORROSION 16 3.3.2 PHYSICAL DAMAGE 17 3.3.3 MISSING BUTTON HEADS 17 3.3.4 UNSEATED BUTTON HEADS 17 3.3.5 CONCRETE WITHIN Two FEET OF BEARING PLATES 17 3.4 SPECIMEN WIRE TEST RESULTS 18 Table 3-4 Specimen Wire Tensile Test Results 18 3.5 CORROSION PROTECTION MEDIUM TEST RESULTS 19 Table 3-5 Corrosion Protection Medium Test Results 19 3.6 CORROSION PROTECTION MEDIUM REMOVAL / REPLACEMENT 19 Table 3-6 Corrosion Protection Medium Quantities Removed and Replaced 20 3.7 FREE WATER ACCUMULATION 20 3.8 TENDON END ANCHORAGE COVER EXAMINATION 20 3.9 TOPICAL REPORT No. 203 EXAMINATION AND TEST COMMITMENTS 21 3.10 Two DAMAGED WIRES IN TENDON V118 21 3.10.1 EXTENT OF CONDITION TESTING 21 3.10.2 INCREASED SURVEILLANCE TENDON SCOPE 22 2010 Augmented Reactor Building (IWL) In-Service Inspection Table of Contents Topical]3.10.3 3.10.4 3.10.5 3.10.6 RESULTS FROM THE EXTENT OF CONDITION TESTING RESULTS OF THE INCREASED SURVEILLANCE SCOPE TENDON EXAMINATIONS DISPOSITION OF TENDON V 118 WITHOUT REPAIR EXTENT OF THE CONDITION TO OTHER TENDONS Report 204 Revision 0 ige 3 of 31 22 22 22 23 4.4.1 4.2 4.3 4.4 4.5 4.6 5.5.1 5.2 6.7.CONTAINMENT SURFACE EXAMINATIONS 24 CONTAINMENT WALL BETWEEN BUTTRESSES 5 AND 6 24 SGR OPENING PATCH 24 BUTTRESSES 4, 5, 6 AND 1 24 DOME AREA TENDON TRENCH 25 TENDON GALLERY BASE MAT 25 TOPICAL REPORT 203 EXAMINATIONS AND COMMITMENTS 25 REPAIRS AND FOLLOW-UP EXAMINATIONS 26 REPAIRS 26 FOLLOW-UP EXAMINATIONS DURING THE 4 0 TH YEAR SURVEILLANCE 26 CONCLUSIONS 27 REFERENCES 29 ATTACHMENTS 31 8.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Purpose, Introduction and Background Revision 0 Page 4 of 31 1. PURPOSE, INTRODUCTION AND BACKGROUND
1.1 Purpose
This topical report documents the results of the Three Mile Island Unit 1 2010 Augmented Reactor Building (JWL) In-Service Inspection.
This augmented in-service inspection (ISI), also referred to herein as a surveillance or ISI, is a one year follow-up inspection after the repair and replacement activities creating and closing a containment opening for the T1R18 Steam Generator Replacement (SGR) Project.1.2 Background Information Measurements, examinations, and tests on randomly selected tendons have been done on a regular basis throughout the life of the plant. The surveillance completed prior to this augmented ISI was the Period 9 surveillance performed from 2009 into early 2010 and was documented in Topical Report No. 203.On June 27, 2007 Three Mile Island was issued License Amendment No. 259 which allowed a one time deferral of the next Type A containment integrated leak rate test (ILRT) to "prior to the startup from TIR18 refueling outage". TIR18 was the refueling outage during which the SGR was completed.
In the associated Safety Evaluation Report by the Office of Nuclear Reactor Regulation the NRC staff recommended augmenting the tendon surveillance program following the SGR. The process established in Subsection IWL of the 2001 Edition of the ASME Code,Section XI (2002 Addenda), was suggested by the NRC staff as an acceptable methodology.
TMI's current containment ISI interval is conducted under the requirements of the 1992 Edition with 1992 Addenda of the ASME Section XI Code (Ref 7.3) as incorporated by reference in 10 CFR 50.55a. The 1992 Edition with 1992 Addenda of the code does not address augmented surveillance requirements following a containment repair or replacement activity.
The 2001 Edition with 2002 Addenda and later editions of the code include paragraphs which stipulate requirements for an augmented surveillance following repair or replacement activities of a concrete containment structure or pre-stressing system.This (TMI 2010) augmented surveillance was conducted in accordance with the requirements of the 2004 Edition of the code with no Addenda (Ref 7.4), referred to herein as the ASME Code. The 2004 Edition of the code with no Addenda is effectively the same as the 2002 Addenda and thus the 2004 Edition was utilized for the basis of this augmented surveillance.
The inspection and acceptance criteria between the 2004 Edition and the 1992 Edition with 1992 Addenda of ASME Section XI were compared and consolidated so that the requirements of the 1992 Edition with 1992 Addenda would be maintained in accordance with the stations IWE/IWL In-Service Inspection Basis Document (Ref 7.1) and 10 CFR 50.55a (Ref 7.2). The scope of this augmented 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Purpose, Introduction and Background Revision 0 Page 5 of 31 surveillance and evaluation of the inspection requirements is identified in Attachment 8.1.1.2.1 Steam Generator Replacement Project Containment Opening The steam generator replacement at Three Mile Island commenced in October 2009 with refueling outage T1R18. During this outage, containment tendons were de-tensioned and/or removed from the containment structure supporting the creation of a construction opening in the containment wall. A rectangular area of concrete was removed from the containment wall and the inner steel containment liner was cut out of the opening. This rectangular opening was located between buttresses 4 and 5. Prior to the removal of concrete, vertical and hoop tendons which routed through the opening were cut out and discarded while a selection of tendons adjacent to the opening was de-tensioned.
Following the steam generator replacement the steel liner was repaired, new tendons were installed, and a concrete patch was poured restoring the containment wall. The new tendons and adjacent tendons were re-tensioned after the concrete patch was cured. The scope of these SGR affected tendons can be found in section 2.2 of Attachment 8.1.1.3 Section Introduction The remainder of this topical report is divided into the following sections: Section 2, Summary of Work Performed and Inspection Results, is a synopsis of the surveillance activities and findings.Section 3, Post-Tensioning System Examinations and Tests, describes measurements, tests and examinations performed on post-tensioning system components, tabulates the results, and includes evaluations of conditions that do not meet acceptance criteria.Section 4, Containment Surface Examinations, describes the examination process and scope, discusses examination findings, and includes evaluations of conditions that do not meet acceptance criteria.
Containment surface examinations performed to satisfy the Topical Report 203 commitments are also covered in this section.Section 5, Repairs and Follow-Up Examinations, is a summary list of required repair work and re-examinations of damaged / deteriorated areas to be done during the 4 0 th year surveillance.
Section 6, Conclusions, summarizes overall conclusions regarding containment integrity as demonstrated by the ISI.Section 7, References, identifies the documents that govern the performance of the ISI and that are otherwise cited in this report.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Summary of Work Performed and Inspection Results Revision 0 Page 6 of 31 2.
SUMMARY
OF WORK PERFORMED AND INSPECTION RESULTS The work performed during the 2010 augmented surveillance and the results of these examinations and tests are summarized in 2.1 and 2.2 below.2.1 Work Performed The 2010 augmented surveillance consisted of testing and visual examination of randomly selected sample tendons from the population of SGR affected tendons (SGR verticals and SGR hoops).This surveillance also consisted of a visual examination of the concrete repair patch of the containment, adjoining concrete to the repair, and the anchorage areas around the SGR affected tendons.Additionally, extent of condition testing and additional tendon inspections were performed in response to a degraded condition identified during work activities.
2.1.1 Post-Tensioning System Testing and Examination The following post-tensioning tendons were randomly selected for testing and examination.
The initial sample size, two tendons in each group (SGR verticals and SGR hoops), meets the 4% per group sampling requirements of the ASME Code, IWL-252 1.The basis and methodology of this random selection can be found in Attachments 8.1 and 8.2.* SGR Vertical Tendons: VI 18, V134* SGR Hoop Tendons: H46-39, H46-41 Two vertical tendons, V 117 and V 119, were added to the surveillance scope for limited (visual only) examination as a result of a degraded conditions identified in V 118 (Attachment 8.3).Examinations and tests of the four sample tendons consisted of the following activities with exceptions as noted: " Collection of corrosion protection medium (CPM) samples from each end of each tendon and laboratory tests on these to determine water content, concentration of corrosive ions and reserve alkalinity
- Inspection and quantification of any free water contained in the anchorage end caps 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Summary of Work Performed and Inspection Results Revision 0 Page 7 of 31" Visual examination of end anchorage hardware (button heads, anchor heads, shims and bearing plates) and concrete within two feet of the bearing plate including the two added scope tendons* Measurements of end anchorage force using the feeler gauge pull out method described in Surveillance Procedure 1301-9.1" De-tensioning of one tendon in each group and extracting a specimen wire for visual examination and tensile tests* Re-tensioning of the de-tensioned tendons with measurements of elongations at several loads* Refilling tendon ducts and end caps with CPM (quantities of CPM removed and replaced measured and documented) including the two added scope tendons Additionally all SGR tendon end anchorage covers were examined for damage and CPM leakage. The bottom ends of all vertical tendons were examined for CPM leakage as well.Examinations and tests were performed in accordance with Surveillance Procedure 1301-9.1 (Ref 7.7), which incorporates the applicable requirements of the 1992 Edition (with 1992 Addenda) of the ASME Boiler and Pressure Vessel Code,Section XI, Sub-Section IWL (Ref 7.3), and the additional requirements specified in 10 CFR 50.55a(b)(2)(viii)(Ref 7.2) as well as the applicable requirements of the 2004 Edition of the ASME code (Ref 7.4). The surveillance procedure also incorporates the applicable requirements of the plant's UFSAR (Ref 7.5).2.1.2 Containment Surface Examination The concrete construction opening patch, adjoining concrete, and concrete around the end anchorages of the SGR tendons was visually examined using the VT-3C procedure defined in paragraph IWL-23 10 of the 1992 Edition with 1992 Addenda of the ASME Code. This examination was performed directly (without optical aids) and remotely using binoculars.
The tendon anchorage end caps and bearing plates of the SGR tendons were examined at the same time.The concrete was examined for evidence of cracking, spalling, efflorescence, and other types of damage / deterioration as identified in ACI 201.1R and ACI 349.3R. This examination was also focused on the concrete repair patch and the adjoining concrete.Bearing plates were examined for detached or missing coatings and corrosion.
Topical Report No. 203, section 5.2, specifies that detailed examination of the construction opening patch will include a visual of the new concrete perimeter and corners for evidence of shrinkage cracks / separation.
This was performed by direct 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Summary of Work Performed and Inspection Results Revision 0 Page 8 of 31 examination from a hanging platform using the VT-1 C detailed visual examination procedure defined in IWL-23 10 of the 1992 Edition with 1992 Addenda of the ASME Code.The last examination performed as specified in Topical Report No. 203 was for evidence and the effects of ground water seepage in the tendon gallery. This was performed by the Responsible Professional Engineer by direct examination.
2.1.3 Extent
of Condition Testing and Additional Tendon Inspections Two broken wires were identified during the as-found visual examination of Tendon Vi 18. Extent of condition testing in the form of a mechanical continuity test of all remaining wires in this tendon was performed and a failure analysis of the wires was conducted.
Additionally, the anchorage caps of the two adjacent tendons, Vi 17 and V 119 were removed and a visual examination was performed.
The two broken wires were removed from V 118 and tensile tested in addition to a specimen wire removed for testing.The extent of condition testing and additional examinations was developed and prescribed by the Responsible Professional Engineer in accordance with IWL-2320, IWL-3222, and IWL-3300 of the ASME code.2.2 Inspection Results The results of the 2010 Augmented Reactor Building In-Service Inspection are summarized below.2.2.1 Post-Tensioning System The results of the post-tensioning system examination, measurements and tests met prescriptive acceptance criteria with one exception which was shown to be acceptable by additional testing, examination, and evaluation.
A listing of specific results follows." All tendon forces were above the predicted values.* Elongations measured during re-tensioning of de-tensioned tendons were within 10% of previously measured values." End anchorage hardware items were free of active corrosion.
All anchorage hardware items were free of cracking and distortion.
- The as found button head conditions were as documented during the previous examinations for all examined tendons except for V 118. Two button heads were 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Summary of Work Performed and Inspection Results Revision 0 Page 9 of 31 protruding on the shop end of VI 18. Further investigation revealed the two wires were broken just below the shop anchorhead." The tensile strength and elongation (at failure) of all wire test samples, including the two broken wires from V1 18, exceeded the minimum required values.* The results of the wire continuity tests on V 118 and examination of the adjacent tendons, V 117 and V 119, found no further damage or broken wires. Evaluation of the condition found V 118 acceptable without repair.* Water content, corrosive ion concentration and reserve alkalinity of all corrosion protection medium samples met acceptance criteria." Concrete adjacent to end anchorages of the surveillance tendons was free of cracks over 0.01 inches wide.* The differences between the quantities of CPM removed and the quantities replaced in all tendons (including V 117 and V 119) were all within 10% of the net duct volume." All SGR Tendon end anchorage covers were free of damage and none showed signs of significant grease leakage.2.2.2 Containment Surface The concrete repair patch had no signs of structural degradation and no cracks were found in the patch or the adjoining original concrete after detailed inspection.
The VT-i C examination was performed directly from a hanging platform without the need for optical aids.The buttress, base mat, and dome trench areas around the SGR tendon anchorages were free of damage / deterioration except for effectively unchanged previously reported conditions.
Water seepage through the tendon gallery outer wall was unchanged from what was observed during the 3 5 th year surveillance.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 10 of 31 3. POST-TENSIONING SYSTEM TESTS AND EXAMINATIONS The following tests and examinations were performed on sample tendons to assess the continuing quality and integrity of the repaired and replaced portions of the post-tensioning system: " Measurement of tendon end anchorage force* Measurement of tendon elongation during re-tensioning" Visual examination of post-tensioning system components and concrete adjacent to bearing plates to detect accumulation of free water, corrosion, deformation, cracking, wire breakage, and wire button head failure" Measurement of wire test specimen strength and elongation at failure* Chemical analysis of CPM to determine water content, reserve alkalinity, and concentration of corrosive ions" Measurement and comparison of CPM removed and replaced" Visual examination of all SGR tendon end anchorage covers to detect damage and corrosion protection medium leakage.All but the last of the above tests and examinations involved a small sample of the SGR tendon population.
All SGR tendon end anchorage covers were examined.Due to an un-acceptable condition identified in tendon VI 18, additional tendons and examinations beyond those already identified were added to the surveillance.
The above mentioned tests and examinations apply only to the initial selection of tendons described below. Tendons V 117 and V 119 were selected for an expanded scope inspection and were subjected to visual examination only. All additional scope tendons, tests, inspections, and acceptability of V 118 are described in section 3.10.Tendons initially selected for tests and examinations were randomly picked from a population that included all tendons in the two SGR tendon groups, vertical and hoop.An additional constraint on tendon selection was added. In both vertical and hoop groups of SGR tendons some tendons were replaced with new tendons and some were re-used and re-tensioned.
At least one new and one re-tensioned tendon from each of the two groups were selected for examination.
The selection basis is documented in Attachment 8.1 and the random selection process is described in Attachment 8.2. The selection included the following:
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 11 of 31* New Vertical Tendon: V134* Re-Tensioned Vertical Tendon: VI 18'" New Hoop Tendon: H46-39'* Re-Tensioned Hoop Tendon: H46-41 One tendon from each group (vertical and hoop) was selected for de-tensioning and removal of a specimen wire for testing. Of the two tendons selected for specimen wire testing, an additional constraint requiring one wire be from a re-tensioned tendon and the other be from a new tendon was imposed as described in Attachment 8.1.3.1 Tendon End Anchorage Forces Tendon end anchorage forces were measured using the liftoff technique described in Surveillance Procedure 1301-9.1 (Attachment 8.4). Forces were measured at both ends of hoop tendons and only at the shop (top) end of vertical tendons.Acceptance criteria cover individual tendon forces and current group mean forces.These forces and associated criteria are discussed in the following paragraphs.
TMI Technical Specification 4.4.2.1.6 states that this report will include a section dealing with trends for the rate of pre-stress loss as compared to the predicted rate for the duration of plant life (after an adequate number of surveillances have been completed).
Additionally, paragraph IWL-3221.1 of the ASME Code requires that the pre-stressing forces for each type of tendon be trended such that predicted tendon forces will not be less than the minimum design pre-stress forces at the next examination.
Because this is the first surveillance of the SGR tendons and a single data set is not sufficient to perform force projections, no such projections are made in this report.3.1.1 Individual Tendon Forces Lift-off tests are performed on inspection sample tendons per IWL-2522 of the ASME Code. The accuracy and calibration of the force measurements are within 1.5% of the guaranteed ultimate tensile strength (GUTS) of the tendon. Tendon force measurement equipment calibrations are listed in Appendices C and F of Attachment 8.7.Table 3-1 lists the measured end anchorage forces, the predicted forces, and the lower acceptance limits, as found on procedure 1301-9.1 Data Sheet 1 (for each tendon) in Appendix A of Attachment 8.7. The time dependant force predictions are documented in Calculation C-1101-153-E410-046 (Ref 7.10). The lower acceptance limits defined in' These tendons were selected for the removal of a specimen wire.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 12 of 31 paragraph IWL-3221.1 of the ASME Code are equal to 95% of the forces predicted for the individual tendons.Table 3-1 Tendon End Anchorage Forces endon T endon End End Lift-Off Average Lift- Predicted 95% of Predicted ID Force (kips) Off Force (kips) Force (kips) Force (kips)Shop /BT 6 1354.4 H46-39 1372.7 1316 1250 Field / BT 4 1391.1 Shop /BT 6 1342.9 H46-41 1356.8 1314 1248 Field / BT 4 1370.7 Shop /Top 1365.3 V118 1365.3 1340 1273 Field / Bottom N/A Shop / Top 1341.7 V134 1341.7 1332 1265 Field / Bottom N/A As shown in the table, all tendon forces are above the lower acceptance limits and are actually above the predicted levels.3.1.2 Group Mean Forces The mean forces in each group of tendons must be equal to or greater than the minimum required force for the group as stated in IWL-322 1.1 of the ASME Code. The minimum required mean force values from Reference 7.9 are:* Vertical Tendons:* Hoop Tendons: 1,033 KIP 1,108 KIP As seen in Table 3-1, all individual tendon forces are well above these minimum values and thus the group mean is acceptable.
3.1.2.1 Group Mean Forces and Projected Group Mean Force calculations for SGR Tendons It is important to note that the SGR tendons will not be included in group mean force calculations for future surveillances.
Future surveillances will include tendons which were not de-tensioned by the SGR. These original tendons were initially tensioned to forces between 70 and 74% of GUTS (Guaranteed Ultimate Tensile Strength) prior to commercial operation in 1974. The SGR tendons were tensioned to forces between 70 and 73% of GUTS in the year 2010. The present forces in these original tendons are appreciably lower than those of the SGR tendons.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 13 of 31 The local pre-stress in areas of the containment located far from the SGR opening patch has little to no influence from the higher SGR tendon forces because the SGR tendons are contiguous and not evenly distributed in the containment structure.
A mathematical mean pre-stress that includes SGR tendon forces is not representative of the local containment pre-stress in areas far from the SGR opening patch. These areas which have lower pre-stress than the SGR opening patch are the limiting cases for determining if the minimum required pre-stress in the containment structure is met. The appropriate (conservative) approach for assessing if the containment structure is maintaining the minimum required (design) pre-stress is to not include the SGR tendon forces in group mean pre-stress calculations.
The same argument applies to calculating group mean force projections.
SGR tendon pre-stress will not be included in the force projections.
Additionally, the SGR tendon pre-stress means and projections do not need to be calculated conditional to the following:
SGR tendons continue to meet individual pre-stress acceptance criteria, and the group mean forces and projections of the original tendons continue to meet the minimum required values.If SGR tendons fail to meet individual pre-stress criteria or group mean forces / force projections of the original tendons fail to meet the minimum required values the issue(s)will be entered into the corrective action process and the need to compute SGR tendon mean forces and / or projections will be assessed.3.2 Tendon Elongations and Re-Tensioning One tendon in each group was de-tensioned to allow removal of a wire for testing.Elongations were measured during the subsequent re-tensioning and compared to the previous values to verify that tendons were intact and that there were no obstructions to tendon motion within the ducts. Following the elongation measurements at overstress force (OSF, nominally 80% of GUTS) each tendon was seated, in accordance with ASME code requirements, at a force between that predicted for the time of the surveillance and 70% of GUTS.Tendons Vl 18 and H46-39 were de-tensioned for wire removal.3.2.1 Elongations Elongations measured during the previous tensioning and re-tensioning are normalized to account for differences between the Pre-tension Forces (PTF) / Overstress Forces (OSF)applied during the previous SGR tensioning and those applied during the 2010 surveillance as well as for differences in the number of wires (one was removed for testing prior to re-tensioning, and two more were removed from V1 18). Normalizing SGR and surveillance values in this manner allows direct comparison of elongations regardless of differences in PTF Values, OSF values, and the number of wires.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 14 of 31 Normalized elongations are expressed as inches per kip per wire (inch-wire
/ kip). This method of computing and comparing tendon elongations meets the requirements of IWL-3221.1 of the ASME Code and 10 CFR 50.55a(b)(2)(viii)(C).
Elongations are acceptable if: 10% > dR = (An 2 -An,) / AnhI *100%Where An, is the normalized elongation determined for the previous stressing An-2 is the normalized elongation determined for re-tensioning dR is the percent difference of normalized elongation Pertinent data documented for SGR tendon tensioning and the 2010 surveillance re-tensioning are tabulated for each of the sample tendons below. These tabulations also list the calculated normalized elongation rates. SGT stressing data is as listed on the SGT tendon stressing data sheets (Attachment A of Ref 7.10). 2010 surveillance re-tensioning data is as listed on procedure 1301-9.1 Data Sheet 4 (for each tendon) and can be found in Appendix A of Attachment 8.7.
2010 Augmented Reactor Building (IWL) In-Service Inspection Post Tensioning System Tests and Examinations Topical Report 204 Revision 0 Page 15 of 31 Table 3-2 Tendon Stressing Elongation Data Tendon Parameter V118 V118 Units (10/26/10)
(10/27/10)
Fosf 1588.6 1581.9 kips dosf 16.9 17.8 inches Fptf 200.0 199.2 kips SGR dptf 6.3 3.8 inches Tensioning dt Ad, 10.6 14 delta inches Wires 169 1692 Number of Wires An 1 1.29 1.71 in-wire/kip Fosf 1577.4 1558.7 1558.7 kips dosf 17.6 18.5 18.5 inches 2010 Fptf 198.3 195.8 195.8 kips Surveillance dptf 7.4 5 4.5 inches Tensioning Ad 2 10.2 13.5 14 delta inches Wires 168 166 166 Number of Wires An 2 1.24 1.64 1.71 in-wire/kip Percent dR -3.88 -4.09 0.00 Derenc I I IDifference In the above table: Fosf is overstress force, -80% GUTS dosf is overstress reference distance Fptf is pre-tension force, -200 kip dptf is pre-tension reference distance An is normalized elongation An = Ad * (# of wires) / (Fosf -Fptf)Tendon V 118 was re-tensioned twice during the 2010 surveillance.
The first re-tensioning was on 10/26/11 and resulted in shop end shim stack height taller than the end cap. The tendon was de-tensioned and re-tensioned the next day transferring some of the shims from the shop end to the field end. Both re-tensioning had acceptable elongations.
The change between the 10/26 and 10/27 elongations can be accounted for as a re-distribution of the tendon's 'twist' inside the tendon duct. This is expected and further documented in a technical evaluation (Attachment 8.3).All changes in elongations, adjusted for effective wires, met the acceptance criteria of less than 10% change from the previous stressing.
2 It should be noted that the SGR as-left inspection of tendon V 118 indicated 169 seated and effective wires. The elongation data presented in the PSC report (Attachment 8.7) computes the elongation assuming 167 effective wires at the time of the SGR re-tensioning.
This is because consideration was given to both scenarios.
All elongation results are acceptable regardless of either number of effective wires assumed at the time of the SGR.
2010 Augmented Reactor Building (IWL) In-Service Inspection Post Tensioning System Tests and Examinations 3.2.2 Re-Tensioning Topical Report 204 Revision 0 Page 16 of 31 After elongations at OSF were measured tendons were re-seated at forces between those predicted for the time of the surveillance and 70% of GUTS as specified in IWL-2523.3 of the ASME Code. Final lock-off forces, as documented in procedure 1301-9.1 Data Sheet 1 (for each tendon) and found in Appendix A of Attachment 8.7, are listed below with the applicable lower and upper limits.Table 3-3 Tendon Re-Tensioning Data Effective Lock-Off Force 70% GUTS Tendon Predicted Force (kip)(kp(k)
Wires (kip) (kip)H46-39 168 1316 1327.8 1385.4 V118 1355.9 (10/26/1 1) 15.166 1340 1369.3 V118 1341.7 (10/27/11)
As shown above, all final lock-off forces are between the specified limits and acceptable.
3.3 End Anchorage Condition Sample tendon end anchorages were visually examined for evidence of corrosion, physical damage, missing b~utton heads, and unseated button heads per IWL-2524.1 of the ASME Code. In addition, the concrete surrounding the anchorage was examined out to a distance of two feet beyond the bearing plate edge to detect cracks >0.0 1 inches in width, spalls, and other indications of damage / deterioration.
Except for Tendon VI 18, the examinations uncovered no indications of unacceptable conditions.
Examination results and acceptance criteria are listed below. Acceptance criteria are derived from ACI 201.1 and ACI 349.3R (Ref 7.14 and 7.11)3.3.1 Corrosion* Acceptance Criterion No evidence of active corrosion" Examination Results No corrosion was found on wires 3 , button heads, stressing washers, or shims of the initial selection of tendons. Minor inactive corrosion was noted on the bushing, anchorhead, and shims or V 119 with no pitting.3 Short segments of some wires are visible when tendons were de-tensioned for specimen wire removal.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 17 of 31 3.3.2 Physical Damage* Acceptance Criterion No cracks or deformations in anchor heads, shims, or bearing plates.* Examination Results No cracks or deformation were found.3.3.3 Missing Button Heads" Acceptance Criterion No missing button heads not previously documented (no specific criterion is set for button heads that detach during surveillance operations).
- Examinations Results No missing button heads were found which were not previously documented.
3.3.4 Unseated
Button Heads* Acceptance Criterion No unseated button heads not previously documented (no specific criterion is set for button heads that are unseated following re-tensioning).
- Examination Results Two unseated button heads were found during as found inspection of VI 18. This condition was immediately documented in the corrective action program.Additional inspections, tests, and the disposition of this condition are discussed in section 3.10.No other unseated button heads were found during as found inspections.
3.3.5 Concrete
within Two Feet of Bearing Plates* Acceptance Criterion No concrete cracks wider than 0.01 inches." Examination Results No cracks wider than 0.01 inches were found.
2010 Augmented Reactor Building (IWL) In-Service Inspection Post Tensioning System Tests and Examinations Topical Report 204 Revision 0 Page 18 of 31 Examination data sheets are ER-AA-335-018 Attachment 5, ER-AA-335-018 Attachment 6, and 1301-9.1 Enclosure 6 Data Sheet 4, and can be found in Appendix A of Attachment 8.7. All conditions were reviewed and met acceptance criteria or were evaluated as acceptable.
3.4 Specimen
Wire Test Results A specimen wire was removed from one tendon in each group for examination and strength testing. Each wire was visually examined over its entire length for corrosion, pitting, and physical damage. Test samples were cut from near each end and near the middle of each specimen wire. These three samples per specimen wire were diametrically measured and tested to determine yield strength, tensile strength and elongation at failure per IWL-2523.2 of the ASME Code and ASTM A370 (Ref 7.16).The visual examinations showed that both specimen wires were free from corrosion, physical damage, and wire diameters were within acceptable limits. As a result there was no need to cut an additional test specimen from the most corroded section of wire as specified in the surveillance procedure.
Tensile testing was performed by Exova Materials Testing Laboratory.
The test data can be found in Appendix A of Attachment 8.7.Tensile strength of all 6 test specimens exceeded the specified lower limit of 240 ksi (the Guaranteed ultimate Tensile Strength, or GUTS) and elongations at failure all exceeded the lower limit of 4% for 0.25 inch ASTM A421 (Ref 7.15) steel wire. The results of the tests tabulated below.All wire tests and examination results met acceptance criteria per IWL-3221.2 of the ASME Code.Table 3-4 Specimen Wire Tensile Test Results Sample Approximate Diameter Yield Ultimate Elongation Tendon Number Sample (in) Strength Strength at Failure Location (ksi) (ksi) (%)I Shop End 0.250 236.2 267.0 5.1 H46-39 2 Middle 0.250 238.6 269.9 5.6 3 Field End 0.250 233.2 267.4 4.6 1 Shop End 0.250 212.9 247.3 4.5 V118 2 Middle 0.250 207.0 246.2 5.9 3 Field End 0.250 208.5 246.6 5.4 2010 Augmented Reactor Building (IWL) In-Service Inspection Post Tensioning System Tests and Examinations
3.5 Corrosion
Protection Medium Test Results Topical Report 204 Revision 0 Page 19 of 31 A sample of corrosion protection medium (CPM) was collected from each end of each sample tendon per IWL-2525 of the ASME Code. Laboratory tests were performed on these samples to determine the characteristics listed (with acceptance limits) below.Table 3-5 Corrosion Protection Medium Test Results Characteristic Water Base Number /Tendon End Chlorides Nitrates Sulfides Content Reserve (ppm) (ppm) (ppm) (% Alkalinity (mg weight) KOH/g)Shop <0.50 <0.50 <0.500 <0.10 73.6 H46-39 Field <0.50 <0.50 <0.500 <0.10 71.2 Shop <0.50 <0.50 <0.500 <0.10 74 H46-41 Field <0.50 <0.50 <0.500 <0.10 71.3 Shop <0.50 <0.50 <0.500 0.19 68.1 V118 Field <0.50 <0.50 <0.500 <0.10 65.1 Shop <0.50 <0.50 <0.500 <0.10 70.8 V134 Field <0.50 <0.50 <0.500 <0.10 63.3 Acceptance Limits <10 <10 <10 <10 >17.5 CPM tests were performed by Suburban Laboratories, Inc. The laboratory results can be found in Appendix B of Attachment 8.7. As shown in the table, all test results meet the acceptance criteria per IWL-3221.4 of the ASME Code.3.6 Corrosion Protection Medium Removal / Replacement When CPM was removed from the tendon sheaths, the quantity removed and the quantity later replaced were documented.
The difference in these quantities provides the information to assess the acceptability of both the level of CPM fill prior to removal and the level following replacement.
If the amount replaced is significantly less than the amount removed, the level is low and must be increased.
If the amount replaced is significantly greater than the amount removed, the reason for the difference (initial fill or leakage over time) must be determined and the situation corrected.
All tendons which were visually examined had CPM removed and replaced.
This includes the two added scope tendons, V 117 and V 119.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 20 of 31 Quantities of CPM removed and replaced are shown in Table 3-4. All differences (absolute values) are less than 10% of the net duct volume limits specified in 10 CFR 50.55a(b)(2)(viii)(D)(2) and IWL-3221.4 of the ASME Code, and are acceptable.
Table 3-6 Corrosion Protection Medium Quantities Removed and Replaced Grease Removed Grease Replaced Difference Duct %Tendon End (Gallons) (Gallons)
Volume (Galos Difference End Total End Total (Gallons)Shop 1 2.65 H46-39 2.5 5.74 3.24 115.26 2.8 Field 1.5 3.09 Shop 0.75 2.21 H46-41 2.25 4.86 2.61 114.86 2.3 Field 1.5 2.65 Shop 3 6.19 V117 4 6.19 2.19 129.86 1.7 Field 1 N/A Shop 5.5 12.39 V118 11.5 12.39 0.89 129.61 0.7 Field 6 N/A Shop 2 4.42 V119 3 4.42 1.42 129.6 1.1 Field 1 N/A Shop 7 8.85 V134 8 8.85 0.85 131.62 0.6 Field 1 N/A 3.7 Free Water Accumulation End anchorages were examined for evidence of free water accumulation per IWL-2524.2 of the ASME Code. No free water was found at any of the anchorages examined.3.8 Tendon End Anchorage Cover Examination Tendon end anchorage covers (grease caps) of the SGR tendons were examined as specified in 10 CFR 50.55a(b)(2)(viii)(A) for damage / deformations and CPM leakage.Only SGR tendon grease caps were examined as all accessible grease caps are examined each five year surveillance.
All covers examined were in sound condition and free of deformations.
There was no evidence of corrosion on the covers and no significant CPM leakage was observed.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 21 of 31 3.9 Topical Report No. 203 Examination and Test Commitments The only Post Tensioning System Test and Examination commitment made in the previous inspection report (Topical Report 203, 3 5 th year tendon surveillance, Ref 7.12)was, "Tendons, anchorage hardware, sample wires, and CPM will be examined / tested as required by the 2001 Edition with 2002 Addenda of the ASME Boiler and Pressure Vessel Code,Section XI, Sub-Section IWL." Containment structure and CPM leakage examination commitments made in Topical Report 203 are discussed in Section 4.As discussed in section 1.2 of this Topical Report and documented in Attachment 8.1, the 2004 Edition with no Addenda of the ASME code was implemented in substitution of the 2001 Edition with 2002 Addenda.3.10 Two Damaged Wires in Tendon V118 Upon initial visual examination of the shop (top) end anchorage hardware of tendon V 118, two button heads were slightly protruding.
This condition was immediately documented in the corrective action process.Further investigation revealed that the two buttonheads were protruding because the wires were broken four inches down where the wire exits the shop end anchorhead.
The full description and detailed evaluation of this event is captured in Attachment 8.3, which includes the failure analysis report and documents the acceptability of the condition without repair. The highlighted events, overview, and overall disposition of the condition are presented below.3.10.1 Extent of Condition Testing Extent of condition testing was conducted which included the following: " Examination of tendon V 118 for signs of damage on the other wires* Verifying mechanical continuity of all the remaining wires in tendon VI 18" Removing the two broken wires from the tendon" Examining the broken wires for corrosion* Sending the wire fractures to a materials testing lab for a failure analysis* Sending intact sample lengths from the two broken wires to a materials testing lab for tensile testing 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 22 of 31 3.10.2 Increased Surveillance Tendon Scope In addition to the testing of tendon VI 18, the scope of the surveillance was increased to include a VT-I examination of the anchorage hardware of the two adjacent tendons, VI 17 and VI 19. The examinations of VI 17 and VI 19 focused on looking for indications of broken wires or other degradation.
3.10.3 Results from the Extent of Condition Testing The location of the fractures along the length of the two broken wires was at the interface of the shop anchorhead and the first shim. The wires were physically damaged at the fracture with a slight bend and shiny areas worn into the wires' surfaces.
These two broken wires were located in the periphery of the anchorhead where wires are most vulnerable to contact with an external object.Upon removal from the tendon, both ends of the two fractured wires were examined for corrosion with none found along the entire length of the wires and the fracture surfaces.The only indications on the wires were a slight bend at the fractures and worn shiny spots in the metal at the fractures.
Using the methodology described in Attachment 8.3, all the remaining wires in tendon VI 18 were individually verified to be mechanically continuous.
None of the wires had any signs, both visually and after mechanical testing, of degradation.
The fractured wires were sent to Exelon Powerlabs for a failure analysis and tensile testing of the wires. The failure analysis indicated that the wires failed under shearing and that the bend and other indentations in the metal adjacent to the wire fractures would act as a stress riser and a source of shearing forces. All tensile tests returned acceptable results showing no degradation of the wires' material properties.
3.10.4 Results of the Increased Surveillance Scope Tendon Examinations The end caps were removed from tendons V 117 and V 119 and a VT-I examination was performed on the anchorage hardware on both the shop and field ends. No conditions indicative of broken or damage wires existed and all conditions noted were previously documented and without change.3.10.5 Disposition of Tendon V1 18 without Repair The results of the extent of condition testing indicate that the remaining wires in tendon V118 have no degradation and are ftilly capable of carrying their design forces. The 169 wire tendon, now reduced to 166 wires (the 2 broken wires and a third, specimen wire, were removed for tensile testing), is still capable of carrying the design pre-stress for a vertical tendon. Evaluation of the acceptability of up to 5 in-effective wires in a vertical tendon is evaluated in Attachment 8.6. Additionally, the as found pre-stress during this surveillance was acceptable with the broken wires and the elongation data of V 118 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Post Tensioning System Tests and Examinations Revision 0 Page 23 of 31 during its re-stressing was also acceptable.
Based on this data and discussion provided in Attachment 8.3, V 118 is acceptable without repair.3.10.6 Extent of the Condition to other Tendons The fractured wires in tendon V 118 were most likely initiated by an external event which physically damaged the wires. The damage which created a stress riser in the wires would have led to wire fracturing either during or after when the tendon was re-tensioned from the SGR. The inspection of the two adjacent tendons and the other three surveillance tendons had no signs of damage indicative of broken wires. It is concluded that the broken wires are an isolated event and there is no common cause which would affect the remainder of the pre-stressing system.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Containment Surface Examinations Revision 0 Page 24 of 31 4. CONTAINMENT SURFACE EXAMINATIONS Containment surface examinations were limited to areas affected by the SGR opening per IWL-2410(d) of the ASME Code. A 100% visual examination of the containment surface is not required per the 2004 edition of the ASME code for this augmented surveillance.
The 1992 edition with 1992 addenda of the code requires a 100%examination every five years. The last full examination was performed during the 35th year surveillance (Ref. 7.12) and the next full examination will be performed during the 4 0 th year surveillance thus meeting the code requirements.
All conditions discussed in the following sections are acceptable with very few requiring review per ACI 349.3R (Ref 7.11). All examination data sheets were reviewed by the responsible professional engineer and the ANII and all indications were acceptable with review.Examination data sheets can be found in Appendix H of Attachment 8.7.4.1 Containment Wall between Buttresses 5 and 6 The entire containment face between buttresses 5 and 6 (including the SGR opening patch) was examined using the VT-3C methodology.
The overall concrete surface shows no evidence of damage or degradation other than non-structural degradation of grout patches in several areas.There are small shrinkage cracks at the concrete surface. All cracks were less than 0.040 inches in width and are acceptable after review (per Ref. 7.11). All surface examination results were reviewed by the responsible professional engineer and the ANII and were all deemed acceptable upon review. No conditions were found which required evaluation.
All conditions were reported with no change from the previous conditions.
4.2 SGR Opening Patch The SGR opening patch and the adjoining concrete was subjected for a detailed visual examination using the VT-1C methodology.
The results of this examination found that the patch is structurally sound and stable. No cracks or other degradation were found in the patch or adjoining concrete.
The visual examination data sheet and a hand sketch of the patch by the VT-1C examiner can be found in Appendix H or Attachment 8.7.4.3 Buttresses 4, 5, 6 and 1 The four buttresses which anchor SGR hoop tendons were examined using the VT-3C methodology.
Cracks were less than 0.010 inches in width and require no further evaluation.
Other conditions noted were degraded grout patches, minor oil stains. All conditions noted were previously reported with no change and are acceptable.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Containment Surface Examinations Revision 0 Page 25 of 31 4.4 Dome Area Tendon Trench The tendon trench on the building dome houses the top ends of vertical tendons. The trench was examined using the VT-3C methodology over the areas from tendon V1 13 to V157, the SGR vertical tendons. No cracks were reported.
The only observations made were a spall in the trench, and bearing plates with corrosion, all of which were previously reported, repaired, and stable.All conditions noted were previously reported with no change.4.5 Tendon Gallery Base Mat The tendon gallery base mat anchors the bottom ends of vertical tendons. The base mat was examined using the VT-3C methodology over the areas from tendon V 113 to V 157.Cracks were less than 0.0 15 inches in width and require no further evaluation.
Other conditions noted were efflorescence, exposed rebar, abandoned tendon trumpets, bearing plates with corrosion that are repaired and stable, and an exposed embed plate with active corrosion and pitting less than 0.0 10 inches. All conditions noted were previously reported with no change and are acceptable.
4.6 Topical
Report 203 Examinations and Commitments Two follow-up containment examinations were prescribed in previous inspection report (Topical Report 203, 3 5 th year tendon surveillance, Ref 7.12). The first was a detailed VT-IC examination of the SGR opening patch and adjoining concrete which was performed and discussed above. The second was a tendon gallery examination for evidence of CPM leakage and the effects of ground water seepage.In addition to the VT-3C examinations discussed above, the responsible professional engineer performed an examination of the walls, ceiling and floor of the tendon gallery for indications of ground water seepage as well as leakage of corrosion protection medium (CPM) from tendon end caps (Attachment 8.5). The examination concluded there is no reason to expect a significant change in the level of ground water seepage between now and the next 5 year surveillance and that the tendon end gasket repair work has eliminated all the significant CPM leaks observed at the start of the 3 5 th year surveillance.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Repairs and Follow-Up Examinations Revision 0 Page 26 of 31 5. REPAIRS AND FOLLOW-UP EXAMINATIONS
5.1 Repairs
The results of the surveillance show that no repair to either the concrete or post-tensioning system is necessary at the present time. The two broken wires in tendon VI 18 were evaluated as acceptable without repair (Attachment 8.3).5.2 Follow-Up Examinations during the 40'h Year Surveillance There are no new follow-up examinations as a result of this augmented surveillance.
The follow-up examinations specified during the 3 5 th year surveillance in Topical Report 203 (Ref. 7.12) shall be completed during the 4 0 th year surveillance.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Conclusions Revision 0 Page 27 of 31 6. CONCLUSIONS The following conclusions are based on and supported by evaluation of the surveillance results:* The force in each individual sample tendon exceeds the lower acceptance limit (95% of the predicted value)." Elongations measured during re-tensioning of de-tensioned tendons are as expected and are within 10% of previously measured values.* All examined wire buttonheads are seated and meet acceptance criteria (as left)." The difference between quantities of CPM removed from sample tendons and quantities replaced were all within 10% of net duct volume showing that tendon duct fill was adequate both as-found and as-left." Corrosion protection medium samples meet specified limits on absorbed water content and concentrations of corrosive ions. The samples also meet the specified lower limit on reserve alkalinity." No free water was detected at tendon end anchorages; therefore it is concluded that water intrusion is not a problem.* Tendon wire samples meet the specified lower limits on ultimate strength and elongation at failure." Concrete surrounding sample tendon bearing plates is free of damage, deterioration, and cracks that exceed 0.010 inches in width." End anchorage hardware items were free of active corrosion.
All anchorage hardware items were free of cracking, distortion, and damage.* Concrete surfaces are free of damage and degradation.
Spalling of grout patches, as noted in various areas, has no structural significance.
The few concrete cracks that exceed the threshold acceptance criteria of 0.010 inches in width are less than 1 foot long and are of no structural significance.
- The SGR opening patch is structurally sound without cracking and is adherent to the adjoining concrete." The SGR tendon end caps are free of damage and any indications of tendon anchorage failure.* SGR tendon end caps are not leaking CPM to any significant degree and no corrective action is required at this time.
2010 Augmented Reactor Building (IWL) In-Service Inspection Conclusions Topical Report 204 Revision 0 Page 28 of 31" The broken wires identified in tendon V 118 were evaluated to be caused by an external event that physically damaged the affected wires. The damage is isolated to the affected wires in V118." Per evaluation, tendon V 118 is acceptable without repair." Overall, the repair of the containment structure and post-tensioning system from the SGR is successful with no deficiencies.
2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Attachment Revision 0 Page 29 of 31 7. REFERENCES
7.1 Basis
Document:
TMI-1-ISI-BASIS-5 Revision 3, FIRST INTERVAL 10 YEAR INSERVICE INSPECTION PROGRAM ISI, IWE/IWL FOR THREE MILE ISLAND NUCLEAR STATION, UNIT 1 (TMI-1)7.2 United States Code of Federal Regulations, Title 10, Part 50, Sub-part 50.55a (10 CFR 50.55a)7.3 ASME Boiler and Pressure Vessel Code (1992 Edition with Addenda through 1992),Section XI, Sub-Sections IWA and IWL 7.4 ASME Boiler and Pressure Vessel Code (2004 Edition with no Addenda),Section XI, Sub-Section IWL 7.5 TMI -Unit 1 FSAR Section 5.7.5, Rev. 20 7.6 TMI -Unit 1 Technical Specification Sections 3.19.1 & 4.4.2.1 7.7 TMI -Unit 1 Surveillance Procedure 1301-9.1, RB Structural Integrity Tendon Surveillance, Revision 22 7.8 TMI -Unit 1 EER JO # 162193, RX Building Tendons, Minimum Required Prestressing Forces 7.9 TMI -Unit 1 Calculation C- 1101-153-E410-028, RX Building Tendons, Minimum Required Prestressing Forces, Revision 0 7.10 TMI -Unit 1 Calculation C- 1101-153-E410-046, TMI-I Reactor Building / Post-Tensioning System In-Service Inspection Program / Tendon Force Prediction 7.11 ACI 349.3R-96, Evaluation of Existing Nuclear Safety-Related Concrete Structures, Published by the American Concrete Institute 7.12 Topical Report No. 203, 3 5 th Year Reactor Building Tendon Surveillance (Period 9), Revision 0 7.13 Exelon Procedure ER-AA-335-018, Detailed General VT-1 VT-iC VT-3 and VT-3C Visual Examination of ASME Class MC and CC Containment Surfaces and Components, Revision 5 7.14 ACI 201.1R-92, Guide for Making a Condition Survey of Concrete in Service, Part 1, Published by the American Concrete Institute 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Attachment Revision 0 Page 30 of 31 7.15 ASTM A421 / A421M, Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete, Published by the American Society for Testing and Materials 7.16 ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products, Published by the American Society for Testing and Materials 7.17 1040851-02, TMI-1 Reactor Building Augmented Examination Requirements for Tendons Affected by SGRP Activities 7.18 1129072-02, Evaluation of Two Broken Tendon Wires on Tendon V 118 as Found During the 2010 Augmented Reactor Building (IWL) In-Service Inspection 7.19 TM-N1063-500, Final Report for the Three Mile Island Unit 1 -2010 Augmented IWL Surveillance 2010 Augmented Reactor Building (IWL) In-Service Inspection Topical Report 204 Attachment Revision 0 Page 31 of 31 8. ATTACHMENTS 8.1 TMI-1 Reactor Building Augmented Examination Requirements for Tendons Affected by SGRP Activities 9 pages 8.2 Selection of Sample Tendons for the 2010 Augmented Reactor Building (IWL) In-Service Inspection 3 pages 8.3 Evaluation of Two Broken Tendon Wires on Tendon V118 as Found During the 2010 Augmented Reactor Building (IWL) In-Service Inspection
- p. 8 Attachment A -VT-I exam data sheets of the as-found top anchorhead of VI 18 p. 10 Attachment B -Wire continuity test procedure and results p. 12 Attachment C -Exelon Powerlabs report on the fractured wires p. 18 Attachment D -Tendon V118 elongation rate graph and brief summary 18 pages 8.4 TMI -Unit 1 Surveillance Procedure 1301-9.1, RB Structural Integrity Tendon Surveillance, Revision 22 87 pages 8.5 Tendon Gallery Examination for Water Seepage and Corrosion Protection Medium Leakage I page 8.6 Passport AR 00982006 A02, Evaluation of Unseated Tendon Wire Buttonheads 3 pages 8.7 Final Report for the Three Mile Island Unit 1 -2010 Augmented IWL Surveillance, Revision 0 p. 29 Appendix A -Surveillance Data Sheets p. 162 Appendix B -Laboratory Analysis of Sheathing Filler p. 173 Appendix C -Jack Calibrations
- p. 194 Appendix D -PSC Surveillance Procedures
- p. 373 Appendix E -TMI Surveillance Procedures
- p. 503 Appendix F -Gauge Calibration Sheets p. 508 Appendix G -Correspondence
- p. 513 Appendix H -General Exterior Concrete Exam 523 pages
..SGR. Te'n'do-'.
Surelac/100 Technical Evaluation TMi1 iReac tor Buldin g uAgmented Examination Reqquirements For: TendonsAffectd bY. SGRP:Ac tvities...
!i Prepared by: Howard.T.
Hill.Re 'viewed by: Evan Johnsoni, Aproved by:;Thomas Geyer P. E. ; Pate::~ !4>,'~?Date: i v Topical Report 204 Revion 0 Attachment 8.1 Page 1 of 9 SGR Tendon Surveillance
/ 100301-1 Page 2 of 9 1. Reason for Evaluation
/ Scope This technical evaluation provides input for the Tendon Surveillance Program for augmented examination of Reactor Building pre-stressing tendons affected by Steam Generator Replacement Project (SGRP) activities.
Steam generator replacement work included making an opening in the Reactor Building concrete wall, steel plate liner, and the associated replacement or de-tensioning
/ re-tensioning of 30 hoop and 45 vertical tendons. The creation and restoration of the opening constitutes a Repair / Replacement (R & R) activity as defined by ASME Section Xl, which specifies that R & R work be periodically examined under the Reactor Building in-service inspection (ISI) program to ensure continuing integrity.
TMI-1 will perform the first of these augmented tendon examinations in late 2010 (during the 1 st Reactor Building ISI interval) as recommended by the USNRC in License Amendment No. 259, which states that the requirements contained in the 2001 Edition (with Addenda through 2003) of ASME Section Xl comprise an acceptable basis for the initial examination activity.
This examination will conform, with the exception discussed in a later part of this evaluation, to this Edition / Addendum of Section XI.Subsequent augmented examinations will conform to the code of record for the applicable Reactor Building in-service inspection interval.
This evaluation covers examinations through the 2 nd ISI interval which extends from 20 April 2011 through 19 April 2021. Examinations during this interval will follow the 2004 Edition (no Addenda) of Section Xl.The 2002 Addendum to Section Xl, and later code editions, contain specific requirements for augmented examination of post-tensioning system tendons affected by R & R work. The augmented examination requirements in the 2002 Addendum and those in the 2004 Edition, which are effectively the same, are the basis for the program as described in this evaluation.
TMI-1 Surveillance Procedure 1301-9.1 provides detailed instructions for in-service examination of Reactor Building concrete and tendons as required by 10CFR50.55a and ASME Section Xl, Sub-Section IWL. Augmented examinations will also be done under this procedure.
This technical evaluation develops the programmatic requirements that are specific to the seventy-five (75)tendons affected by SGRP work. These requirements will be incorporated into Procedure 1301-9.1 under 01040851-04 so that the entire in-service examination of Reactor Building concrete and tendons can be performed under a single document.Topical Report 204 Revion 0 Attachment 8.1 Page 2 of 9 SGR Tendon Surveillance
/ 100301 -1 Page 3 of 9 Acceptance criteria applicable to the augmented examinations are not fully addressed in Sub-Section lWL. This technical evaluation develops comprehensive criteria for inclusion in Procedure 1301-9.1.Repair of the post-tensioning system is not within the scope of this Technical Evaluation.
This evaluation addresses only examination.
Any repairs that are required as a result of examination findings will be done in accordance with Section XI.The examination requirements addressed in this evaluation apply only to the Reactor Building pre-stressing tendons and associated anchorages.
No other plant components are considered herein.This technical evaluation covers only the examination requirements that will be a part of the 1 st and 2 nd Reactor Building ISI intervals.
Subsequent updates to the program will be performed in accordance with the requirements in the applicable future amendments to 10CFR50.55a.
- 2. Detailed Evaluation TMI-1 will examine the tendons affected by the SGRP work in accordance with the requirements of the 2004 Edition 1 (no Addenda) of the ASME Boiler and Pressure Vessel Code, Section Xl, Sub-Section IWL. These requirements are summarized below.IWL-2521.2(a) states that tendons affected by R & R activities shall be selected at random and examined in accordance with Table IWL-2521-2.
IWL-2521.2(b) states that any randomly selected tendon which is inaccessible for full examination shall be designated as exempt and replaced in the sample by the nearest accessible tendon included in the population affected by the R & R activity.
It further requires visual examination of the exempt tendon anchorages per IWL-2524 and sampling / testing of corrosion protection medium (and free water, if found) per IWL-2525 to the extent that this can be done.Table IWL-2521-2 lists the following requirements.
- An initial examination between 9 and 15 months following the completion of the R & R activity and subsequent examinations as specified by IWL-2420, which defines the schedule for tendons not impacted by the SGRP work.Section Xl requirements pertinent to this technical evaluation and the augmented examination program are essentially the same in both the 2001 Edition (with Addenda through 2003) and the 2004 Edition.Topical Report 204 Revlon 0 Attachment 8.1 Page 3 of 9 CI zO4 o'TS 1-0 a 4 SGR Tendon Surveillance
/ 100301-1 Page 4 of 9" A sample size of 4% of the affected tendons in each group (vertical and hoop)for the first two examinations and, if the results are acceptable, 2%subsequently, with all percentage samples rounded up to the next whole number of tendons." All tests and examinations listed in Table IWL-2500-1 Category L-B which include lift-off force measurement, end anchorage visual examination, wire testing and corrosion protection medium (and free water if found) testing.* Completion, during the next regularly scheduled outage, of all tests /examinations deferred due to plant operating conditions.
Implementation of these requirements under the program is detailed in the following paragraphs.
2.1 Examination
Schedule The SGRP R & R activity ended with the 17 January 2010 examination that followed completion of the post-repair pressure test. The first augmented examination will be done between 17 October 2010 and 17 April 2011. This satisfies the table IWL-2521-2 requirement that this examination be performed 9 to 15 months after the R & R completion date.Subsequent examinations of tendons affected by the SGRP work will be concurrent with the regularly scheduled Reactor Building in-service inspections during fall outages in 2013, 2019, 2023, 2029 and 2033, unless changes to the plant fuel cycle or regulatory requirements alter this schedule.Topical Report 204 Revion 0 Attachment 8.1 Page 4 of 9 SGR Tendon Surveillance
/ 100301 -1 Page 5 of 9 2.2 Examination Scope The SGRP work affected 30 of 330 hoop tendons and 45 of 166 vertical tendons.Twenty two hoops and ten verticals were replaced with new tendons; the remainder were de-tensioned and subsequently re-tensioned as summarized below." New Vertical Tendons (10): V131 through V140* Re-tensioned Vertical Tendons (35): V1 13 through V130 & V141 through V1 57" New Hoop Tendons (22): H46-30 through H46-39 & H51-28 through H51 -39" Re-tensioned Hoop Tendons (8): H46-28, H46-29, H46-40, H46-41, H46-42, H51-40, H51-41 & H51-42 2.2.1 Examination Sample Selection Sampling requirements applicable to the first examination, to the second examination and to the subsequent examinations differ as addressed below.(a) First Examination The sample for the first examination will consist of 2 verticals (4% of 45 rounded up) and at least 2 hoops (4% of 30 rounded up). These will be selected by random draw subject to the following conditions.
e The first examination will be performed while the plant is in operation and the Buttress 1 ends of the H51 tendons are inaccessible for safety reasons. If an H51 sub-group tendon is selected by random draw, it will be treated as exempt per IWL-2521.1 and replaced with the corresponding H46 sub-group tendon (or the nearest thereto if already selected for examination) and: o Examined during the fall 2011 outage as specified in Table IWL-2521-2 Note 4 or;Topical Report 204 Revion 0 Attachment 8.1 Page 5 of 9 0I 10- 0 IS" I- 0 SGR Tendon Surveillance
/ 100301-1 Page 6 of 9 o Examined during the regularly scheduled surveillance in the fall of 2013, in which case an additional H-46 sub-group tendon will be randomly selected and added to the first examination sample 2., The overall examination sample (vertical and hoop considered together)must include at least one new tendon and at least one re-tensioned tendon. The population from which the final sample tendon is drawn will be limited to new or re-tensioned tendons if necessary to meet this requirement.
The procedure used to make the random selection will be documented on a data form to be added to Procedure 1301-9.1.(b) Second Examination The sample for the second examination will consist of any tendons deferred from the first examination as well as 2 verticals and 2 hoops selected by random draw from a population that excludes those in the first examination sample.The overall examination sample must include at least one new tendon and at least one re-tensioned tendon. The population from which the final sample tendon is drawn will be limited to new or re-tensioned tendons if necessary to meet this requirement.
The tendons to be included in the second examination sample will be selected following the completion of the initial examination.
The procedure used to make the random selection will be documented on the data form cited in (a) above.(c) Subsequent Examinations If acceptance criteria are met in both the first and second examinations, the samples for subsequent examinations will consist of 1 vertical (2% of 45 rounded up) and 1 hoop (2% of 30 rounded up) selected by random draw from a population that excludes those previously examined.
The overall examination sample may include any combination of new and re-tensioned tendons.If acceptance criteria are not met in either the first or second examination, the requirements in (b) above will continue to apply until the results of two 2 This option is not in compliance with Table IWL-2521-2 Note 4 which specifically requires that tendons declared inaccessible for operational reasons be examined during the next regularly scheduled outage. It is presented as a reasonable alternative that requires an expanded sample in exchange for additional deferral of randomly selected inaccessible tendons.Topical Report 204 Revion 0 Attachment 8.1 Page 6 of 9 0 t t '-j C. -,a 9 t- 0 -.1 SGR Tendon Surveillance
/ 100301-1 Page 7 of 9 consecutive examinations are acceptable, at which time the preceding paragraph will apply.The tendons to be included in each subsequent examination sample will be selected following the completion of the prior examination.
The procedure used to make the random selection will be documented on the data form cited in (a)above.2.2.2 Documenting Tendons Examined SGRP scope tendons will be identified on a master tracking list that must be added to Procedure 1301-9.1 under 01040851-06.
This tracking list will be updated following the completion of each examination to identify all tendons that have been examined and removed from the population from which future examination samples are to be drawn.2.2.3 Examinations Each examination will consist of all visuals and tests identified in Table IWL-2500-1, Category L-B as follow.* Visual examination of end anchorage hardware including anchor head, button heads, shims and bearing plate for evidence of corrosion, cracks and distortion.
- Examination of concrete surrounding the bearing plate for evidence of crack development, spalling and other types of damage / deterioration." Collection and testing of corrosion protection medium samples for water content, contaminants and reserve alkalinity as specified in Table IWL-2525-1.* Collection and testing of any free water found in the anchorage area.* Measurement of lift-off force." Testing of wires extracted from one vertical and one hoop tendon. For the first two examinations, one wire must be a new wire and one must be an original wire.Topical Report 204 Revion 0 Attachment 8.1 Page 7 of 9 SGR Tendon Surveillance
/ 100301 -1 Page 8 of 9 2.3 Acceptance Criteria Acceptance criteria for individual SGRP scope tendons are the same as those for regular surveillance sample tendons. These criteria, which conform to the requirements of IWL-3220, are identified in Procedure 1301-9.1.Sub-Section IWL does not address combining the SGRP scope tendons and regular surveillance sample tendons for determining group mean lift-off force.Since the SGRP scope tendons were seated at 70% -73% of specified minimum ultimate tensile strength and since time dependent losses in these tendons will be small, measured anchorage forces are expected to remain relatively high throughout the operating lifetime of the plant. Therefore, including the measured anchorage forces in the vertical and hoop group means would probably introduce a non-conservative bias into the computed values.For the above reason, measured forces in SGRP scope tendons will not be included in either the normalized mean computations or the trend analyses.Acceptance criteria applicable to measured forces in individual tendons are based on expected (predicted) values. SGRP scope tendon predicted forces are computed and tabulated in Calculation C-1101-153-E410-046 (in course of preparation).
This calculation is tracked under 01040851-03.
2.4 Examination
Personnel, Measuring
& Test Equipment and Procedures Requirements for examination personnel training / certification, control of measuring
& test equipment and examination procedures applicable to the SGRP scope tendons are the same as those that apply to regular surveillance sample tendons and that are currently addressed in Procedure 1301-9.1.2.5 Removal / Replacement of Corrosion Protection Medium Procedures and criteria covering the removal / replacement of corrosion protection medium and evaluation of the quantities documented are the same for both SGRP scope tendons and regular surveillance sample tendons. These are addressed in Procedure 1301-9.1.3. Conclusions
/ Findings This technical evaluation defines a program. Conclusions and findings do not apply.Topical Report 204 Revion 0 Attachment 8.1 Page 8 of 9 SGR Tendon Surveillance/
100301-1 Page 9 of 9 4. References References used in the preparation of this technical evaluation are listed below.4.1 Code of Federal Regulations, Title 10, Part 50, Paragraph 50.55a, Codes and Standards, Current Amendment.
4.2 ASME Boiler and Pressure Vessel Code, Section Xl, In-Service Inspection, 2001 Edition with Addenda through 2003.4.3 ASME Boiler and Pressure Vessel Code, Section Xl, In-Service Inspection, 2004 Edition (no Addenda).4.4 Calculation 38455-CALC-C-005, Containment Opening Analysis and Design for Temporary Opening and Restoration, Revision 6.4.5 TMI-1 Surveillance Procedure 1301-9.1, RB Structural Integrity Tendon Surveillance, Current Revision.4.6 Amergen Energy Company, LLC / Docket No. 50-289 / Three Mile Island Nuclear Station, Unit No. 1 / Amendment to Facility Operating License, Amendment No. 259 / License No. DPR-50.4.7 TMI-1 Calculation C-1 101-153-E410-046, TMI-1 Reactor Building / Post-Tensioning System In-Service Inspection Program / Tendon Force Prediction, (in course of preparation).
Topical Report 204 Revion 0 Attachment 8.1 Page 9 of 9 Selection of Sample Tendons for the 2010 Augmented Reactor Building (IWL) In-Service Inspection The selection of sample tendons for the 2010 Augmented Tendon Surveillance consists of 4% of the following tendon populations:
- SGR Affected Hoop Tendons -H46-28 to H46-42, H51-28 to H51-42* SGR Affected Vertical Tendons -V 13 to V157 Two tendons in each group are to be selected for surveillance testing. One tendon in each group is to be selected for specimen wire removal and additional testing. In addition to the selection requirements imposed in the 2004 Edition (no Addenda) of the ASME Boiler and Pressure Vessel Code,Section XI, Subsection IWL, the following restraints were placed on the selection: " Each group consists of both new and re-tensioned tendons. The random selection from each group must contain at least one new and one re-tensioned tendon" Of the two tendons selected for specimen wire removal and additional testing (one from each group), at least one such tendon must be a new tendon and the other a re-tensioned tendon.To make the selection, each tendon per group was assigned a unique number in the following spreadsheet and the tendon identifier coded with a trailing hyphen or without, representing a new SGR tendon or a re-tensioned SGR tendon respectively.
A random number generator was configured to generate a number between one and forty-five and was used to pick the first vertical tendon. If a number corresponding to a hyphen coded (new) tendon is first generated and selected, then subsequent numbers will be generated until the first number corresponding to a non-hyphen coded (re-tensioned) tendon makes the second vertical tendon selection.
Likewise if a non-hyphen coded (re-tensioned) tendon is selected upon the first number generated, then subsequent numbers will be generated until the first number corresponding to a hyphen coded (new) tendon makes the second vertical tendon selection.
The same procedure described above was also used to make the surveillance tendon selection for the hoop group with random numbers limited to between one and thirty.Next the two selected vertical tendons were assigned the unique numbers one or two (in the Wire # column of the attached spreadsheet).
The random number generator was configured to produce a number one or two. The associated tendon selected in this process is assigned to have a specimen wire removed and additional testing. If the selected vertical tendon in this step is a hyphen coded (new) tendon, then the hoop tendon selected for specimen wire removal and additional testing will be the non-hyphen coded (re-tensioned) tendon, and vice versa.Topical Report 204 Revion 0 Attachment 8.2 Page 1 of 3 The selection made based on the results of the random numbers generated is: " V 118, re-tensioned SGR tendon selected for specimen wire removal" V134, new SGR tendon* H46-39, new SGR tendon selected for specimen wire removal* H46-41, re-tensioned SGR tendon Attached is the spreadsheet listing all the SGR tendons by group and hyphen coded by new / re-tensioned tendons. Each tendon per group had a unique number used for the initial selection.
The two selected tendons in the vertical group were assigned a second number, unique to each tendon in this second numbering sequence.
Tendons whose unique numbers are dark orange colored were selected for examination.
Tendons whose designator is bolded were those selected for specimen wire removal and additional testing.The light coloring in the legend labeled "Nearest Substitute" was intended to be used if a H151 -XX tendon was selected.
This is because those tendons are inaccessible during the time of this schedule surveillance due to their location above the MSSV's and a nearest substitute would need to be designated from the H46-XX group if one were selected.
No H151 -XX tendons were randomly selected and thus nearest substitutes were not needed.Topical Report 204 Revion 0 Attachment 8.2 Page 2 of 3 SGR Random Sample Selection Wire # Number ndon Number Tendon I 11 1 I-8 9 10 11 12 13 14 15 16 17 18 19 20 91 Randomly Selected= Nearest Substitute N yi n = SGR Affected Tendon W y = SGR Replaced Tendon 2 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Post Containment New SGRP Re-Tensioned New SGRP Re-Tensioned Repair/Restoration Tendons for SGRP Tendons Tendon forWire SGRP Tendon for Augmented Exam Inspection for Inspection Removal Wire Removal Tendon Vertical V134 V118 V1 18 Location Horizontal H46-39 H46-41 H46-39 I Topical Report 204 Revion 0 Attachment 8.2 Page 3 of 3 1129072-02 Evaluation of Two Broken Tendon Wires on Tendon V118 as Found During the 2010 Augmented Reactor Building (IWL) In-Service Inspection Preparer: Evan Johnson Co-Preparer:
Howard T. Hill, P.E.Date: 2/14/11 Date: 2/14/11 Date: 2/14/11 Date: 2/22/11 Reviewer: Approver: Gene Navratil Tom Gever Copies to be forwarded to: Dan Fiorello, Heather Malikowski, and Hien Do Topical Report 204 Revion 0 Attachment 8.3 Page 1 of 18 Page 1 of 18 1129072-02
- 1. Reason for Evaluation and Scope The purpose of this technical evaluation is to evaluate the acceptability of two broken tendon wires on tendon V 118 as found during the 2010 Augmented Reactor Building (IWL) In-service Inspection.
The extent of condition and wire sample results are also documented and evaluated in this document.
This evaluation is required per ASME XI 2004 ed. with no addenda and is prepared per such requirements.
Broken wires in small numbers do not adversely affect a tendon's ability to hold its required pre-stress.
This has already been evaluated in the past for up to five broken/in-effective wires in a 169 wire tendon (Ref 4.5). The as left condition of tendon V 118 is 166 effective wires and requires no further evaluation.
This evaluation is limited to the extent of condition for un-expected discovery of two broken wires in tendon Vi 18.2. Detailed Evaluation This evaluation has been prepared IAW Exelon Procedure CC-AA-309-101.
A technical task risk and rigor assessment and pre-job brief has been conducted JAW Exelon Procedure HU-AA-1212.
This evaluation screened as having a risk ranking of 1 (lowest risk ranking) and as such, the existing review process required in CC-AA-309-101 is adequate.This evaluation is developed using inspection data inputs from the reactor building in-service inspection contractor (Precision Surveillance Corporation), an Exelon Powerlabs failure analysis report, and first hand accounts of the events from the preparer and co-preparer.
All data sheets and reports have been reviewed by the preparer, co-preparer, and, where applicable, an authorized nuclear in-service inspector (ANII).During the scheduled visual inspection of vertical tendon V 118 for the 2010 Augmented Reactor Building (IWL) In-service Inspection, the as-found VT- I exam documented two of the 169 tendon wire buttonheads (ends) were not fully seated on the top (shop) end tendon anchorhead (Attachment A). The initial observations of the VT-I examiner were that the buttonheads were protruding
-0. 1 inches above the anchorhead seating surface and that the two buttonheads appeared to be slightly oversized.
Per ASME XI 2004 ed. with no addenda, broken or unseated wires are not an acceptable condition and shall be evaluated (IWL-3221.3, IWL-3222).
This report will evaluate the cause of the condition, applicability of the condition to other tendons and any other plants at the same site, acceptability of the containment without repair of the item, the necessity for repair or replacement, and the extent, nature, and frequency of additional examinations (IWL-33 10).The following investigation plan and disposition was developed by the Responsible Engineer (Howard T. Hill) in accordance with IWL-2320, IWL-3222, and IWL-3300 of ASME XI 2004 ed. with no addenda, and TMI Procedure 1301-9.1.Topical Report 204 Revion 0 Attachment 8.3 Page 2 of 18 Page 2 of 18 1129072-02 IR 1129072 was written to document this recordable indication (per ER-AA-335-018) and the recommended actions were to perform a mechanical continuity test of the two wires after the tendon had been de-tensioned to verify whether they were broken or not broken.Force in the tendon was next measured per the planned inspection prior to de-tensioning.
The tendon pre-stress met acceptance criteria having a pre-stressing force slightly greater than predicted (Ref. 4.6 & 4.8).The tendon was detensioned after the pre-stress measurement.
A wire pulling assembly was connected to the two protruding buttonheads one at a time and was pulled with a force less than the yield strength of the wire to verify the wires' mechanical continuity.
Both buttonheads pulled out of the anchorhead with -4" of wire up to fractures in the wires. The breaks in the two wires had nearly identical fracture characteristics and were located where the wire exits the -4" thick anchorhead.
Both fracture ends of the two 4" wire stubs showed visible indications of external damage in the form of a slight bend and a shiny spot where mechanical contact was made with the wires during some past event.No corrosion was observed.
Both wires were located in "corner" positions on the same side of the top (shop) anchorhead (see page 2 of Attachment A) and are most vulnerable to external mechanical damage in these positions within the tendon. IR 1129648 documented the discovery of the broken wires.The tendon was next pulled up to inspect the break on the remaining length of the wires in the tendon and to examine the other 167 wires for signs of damage. The mating broken ends of the two wires were observed to have similar indications to the fractured area on the 4" pieces removed. The remaining wires did not appear to have any damage over all observable areas above or below the top (shop) anchorhead and no corrosion was observed.The remaining 167 wires were each checked for mechanical continuity.
This was done one of two ways. The first was to allow the detensioned tendon wires to protrude from the bottom (field) anchorhead several inches. A buttonhead at the top end is then attached to the wire pulling assembly and the wire is pulled until a lower buttonhead is observed to retract into the tendon. The lower buttonhead is then marked as a continuous wire. This method was performed for some of the wires until it became too difficult to connect the wire pulling assembly to the upper buttonheads.
This difficulty comes from the need to hand pry the buttonheads up from the top (shop) anchorhead against the weight of the hanging tendon wire.The remaining wires were tested by attaching the wire pulling assembly to each wire from the bottom side and pulling on the wire to a force of 5500 -6000 lbf. The assumption of this test is that a continuous wire will (approximately) linearly elongate up to the maximum force which was applied while measured with a dynamometer.
A non-continuous wire is expected to pull out with a force much less than 5500 lbf. For this testing, TMI M&TE Dynamometer
- 0002788915 was used and is documented in the Topical Report 204 Revion 0 Attachment 8.3 Page 3 of 18 Page 3 of 18 1129072-02 PIMS Work Order R2319507 Activity 02 (Ref. 4.8). All of the 167 wires were found to be mechanically continuous per this testing (Attachment B).During the manipulation of the tendon and wires, one of the lower ends of the two broken wires partially fell out of the bottom (field) anchorhead and was removed by hand. The lower end of the other broken wire was found during the mechanical continuity test. The wire was pulled out of the tendon from the bottom with a recorded maximum force of-100 lbf. These events provide validity that a wire holding 5500 lbf is continuous.
The removed broken wires were each cut into 46 four foot lengths plus the broken 4" ends. Each of the 46 segments (per wire) was tagged with a piece of red tape labeled with: an incremental number, a black dot or absence of (differentiating the two wires), and an arrow pointing to the bottom (field) buttonhead direction of the wires (marking the up/down orientation of the wire segments).
Samples from both ends and the center of each wire were sent to Exelon Powerlabs for a failure analysis of the wire breaks and a material strength test of the wires IAW ASTM A370, the test specification for the ASTM A421 0.25" diameter round wires. The Powerlabs failure analysis report (Attachment C)concluded: "All tensile test results for Load @ 100, Breaking Load & % Elongation, were in accordance with 0.250" diameter wire spec ASTMA 421acceptance criteria.The two V-1 18 broken wires had fractured surfaces indicative of both shearing forces and ductile overload.
Circumferential indentations and slight bending was observed adjacent both wire fractures; most likely from where the wire exits the anchor head. This location would be characterized, as a geometric stress riser as well as a source for shearing forces synergistic with the mechanical notch would significantly contribute to premature wire failure.Another unconfirmed possible contributing factor would be if the overall effective wire length was slightly shorter than the others within the tendon, hence under a greater share of the total load. " All test samples of the broken wires met the specifications for the material and showed no signs of degradation of the material properties.
The broken sections of wire exhibited signs of external mechanical damage and the fracture surfaces indicated shearing forces and ductile overload.
The mechanical damage to the wires, in the form of slight bending and circumferential indentations, acts as a stress riser and a source of shearing.The relative positions of the two broken wires in the upper anchorhead can be observed in page 2 of Attachment A. The wire locations in the extreme corners of an anchorhead are most likely to expose the wires to mechanical contact with the anchorhead, shims, bearing plate, or other external objects. A wire damaging event could have happened during original tendon installation or during de-tensioning or re-tensioning activities during the Steam Generator Replacement Project (SGRP). It is plausible that these two corner wires could have been damaged without the event affecting any of the other wires Topical Report 204 Revion 0 Attachment 8.3 Page 4 of 18 Page 4 of 18 1129072-02 in the tendon. Additionally, the visual inspection of the tendon wires exiting the top anchorhead did not have any signs of damage besides the two broken wires.In addition to testing the broken wires and verifying the continuity of the remaining wires in tendon V1 18, additional examinations included removing the end caps from the two adjacent tendons, VI 17 and V1 19, and performing a VT-i exam to verify the absence of any protruding buttonheads or other indications of broken wires. VI 17, VI 19, and the other randomly selected surveillance tendon's as found exams matched the documented as-left condition from the SGRP with no indications of broken wires not previously documented.
No other additional examinations for the extent of condition were performed.
At the conclusion of the tendon wire testing, a sample wire (3 rd wire) was removed from VI 18 for the planned materials testing per IWL-2523.
VI 18 was then re-tensioned with 166 effective wires in accordance with the site surveillance procedure and IWL-2523.3.
V 118 was re-tensioned twice because after the first tensioning, the shim stack on the top (shop end) was taller than the end cap could fit. The tendon was de-tensioned, some shims re-distributed to the bottom (field end), and then re-tensioned for a second time.Both times the tendon was tensioned to an acceptable force and the tendon elongation rate was well within the acceptance criteria of <10% difference from previous tensioning (Attachment D).3. Conclusions The conclusions presented herein are based on assumptions that the inspection inputs are valid and accurate.
It is possible that these wires have been broken since plant construction and the very minor buttonhead protrusion not identified until this surveillance.
However, due to the ease of which the lower end of the broken wire fell from the lower anchorhead and the disturbance the tendon experienced from the SGRP, it is most probable that the wires were damaged during SGRP re-stressing of the tendon.It is concluded that the broken wires are an isolated event affecting only the two broken wires in V 118 and was most likely caused by external mechanical damage to the wires assumed to have occurred during the SGRP. The acceptable material properties of the wire samples, Exelon Powerlabs analysis of the fractures, positions of the broken wires at the anchorhead corners (most vulnerable to external mechanical damage), verified mechanical continuity of the remaining wires, acceptable tendon stressing at the conclusion of the surveillance, and the lack of any other indications on either of the neighboring tendon's additional examinations or any other surveillance tendon's examinations support this conclusion.
Tendon V 118 is acceptable with the remaining 166 effective wires and the previous evaluation presented in Reference
4.5 justifies
acceptability of the tendon and containment without any repairs to V1 18. Per the Responsible Engineer, there is no need to repair or replace any tendon wires. V118 was left with all buttonheads fully seated, and tensioned to a force between the predicted force at the time and 70% of the Topical Report 204 Revion 0 Attachment 8.3 Page 5 of 18 Page 5 of 18 1129072-02 guaranteed ultimate tensile strength of the tendon adjusted for effective wires per IWL-2523.3. The additional examinations concluded with the inspection of the two adjacent tendons (V 117 and V 119) and materials testing of the broken wires and no further extent of condition examinations are required (IWL-33 10(e)).Topical Report 204 Revion 0 Attachment 8.3 Page 6 of 18 Page 6 of 18 1129072-02
- 4. References 4.1 4.2 4.3 4.4 4.5 4.6 ASME XI 2004 Ed.10 CFR 50.55a ASTM A370 and ASTM A421 TMI procedure 1301-9.1 Rev. 21, RB Structural Integrity Tendon Surveillance Passport AR 00982006 A02 C-1101-153-E410-046, TMI-1 Reactor Building Post-Tensioning System In-Service Inspection Program Tendon Force Prediction
4.7 Exelon
Procedure ER-AA-335-018 Rev. 005, Detailed General VT-1 VT-IC VT-3 VT-3C Visual Examination of ASME Class MC and CC Containment Surfaces and Components 4.8 TMI PIMS Work Order R2139507 (2010 Augmented ASME IWL Inspection)
- 5. Attachments Attachment A'Attachment B'Attachment C Attachment D VT- I exam data sheets of the as-found top anchorhead of V 118 Wire continuity test procedure and results Exelon Powerlabs report on the fractured wires Tendon V 118 elongation rate graph and brief summary 1: It should be noted that the depictions of the broken wire locations between Attachment A and B are different.
This is because Attachment A depicts the top (shop) anchorhead and Attachment B depicts the bottom (field) anchorhead.
During plant construction, the tendons were delivered (from the fabrication shop) with the wires threaded and button-headed through the shop end anchorhead.
The tendon is then pulled through the building's tendon ducts, and the bottom (field) anchorhead is installed in the field. There is no correlation between a wire's position in the shop and field anchorheads.
Topical Report 204 Revion 0 Page 7 of 18 Attachment 8.3 Page 7 of 18 1129072-02 Attachment A ER-AA-335-018 Revision 5 Page 31 of 32 ATTACHMENT 5 ASME IWL (Class CC) Containment Tendon Anchorage Detailed Visual or VT-1 Visual Examination NDE Report Page 1 of I Station Unit Date Report No A IWO NOvs) %-"1g r-7 Tendon Anchorage No .-1/p Tendon End 9 Shop _ _Locafon TneGaliery Buttress Elevat,on Beanng Plate I D Beannig Rate 1 U0 e Arcoric Head I D 71 Bus.'rin I D 5ýr7f V pe TT-e Of Exam N rect __fRemote As Found Exam 7j As LeVI Exam Foowin Retensonfrg Of Tendons Which Have Been Detentioned M&TE Used I etCr T rS'a No 7ACal Due Date I umination UWe illumination verifed Date Tm Special 'Specific In ucton Component I Item Number ana RESULTS Explanation 1 Notes Description NI RI TYPF iQ1 l(qk.kth lhill Be Attached Deplting Location Of Al SMissing Protruding Unseated Wires Resul00 ger- (0 NI -No Inoicavors RI -Recordabte Indcaton 10 -ýntorrnamiun Only Recordable indication Type Codes A Missing Vres H Ciacks 1) Othet (Explarn 8 missing Butto~n Heads I Pitting C Protrudling I Unsealed Wires J Ntis Gouges MAct-aincai Griamage D arolien Pres K Uneven Shim E Active Corrosion L Excessive Snim Gaps F Other Corrosion M Gasket Seaiing Surface Oamage G Evidence Of Free W/iter (QOuandthj N Surface Discontinuities Deflections Sipplen-ental nlorrnmaton S No Sketch Photo []Video 1 EXAMINER/'EVALUATOR:
rn [L+_EL
... .'int & ... ........ .__ _...........
EXAM~N~~~R -LEVEL ____DATE STATION/ADMIN REVIEW Th lis, Q_++ DATE I tj A L This section to be completed only if ExaminerlEvaluator notes RI or Unacceptable condition.
RI or Unacceptable results Acceptable yes fl No 0\JO (K "-Addtonal Azticns LEVEL III or RI REVIEW DATE 7 &*V~ iI _____ANII REV'EW ; r' , C)At T f E i Topical Report 204 Revion 0 Attachment 8.3 Page 8 of 18 Page 8 of 18 1301-0.1 Revision 21 ENCLOSURES Pap 9 of 16 IDat Shook 4 Tendon Butionhoad Inspection
\ ~\ ,,, /'J/N j/~ ,RB Tendon Swav"laceý4% 3r/ ~~~~COMMENT
- I 4~0 0 .0 ! '3- .('Q.OCJ~u-
', 1 OD 0 cc/ INSPECTED BY , I, CONTRACTOR FOREMAN----,,Di" VEMRIFIED BY co 0Tr~ COGNIZANT QV INSPECTORt' r'3 -COGNIZANT MECWSTRUCT ENGFt-" 4REVIEWED By INSPECTION PERIOD -Ted# I-NSC' REND: FIEL (1 piece washer)SHOP __(2 piece washer)k)0,.0, 1129072-02 Attachment B TMI-1 2010 Augmented Tendon Surveillance Wire Continuity Test Data Sheet 1 of 2 (Use for Verifying Continuity of Vertical Wires by Pulling at the Bottom End)Tendon Number IL /f Date / tV / Sigrilatpre 1 _Dynamomeler ID No.ýO-APff!Uf
/ Cal due Dale Sheet 1 Instructlons:
- 1. Connect pulling device with in-line dynamometer to each wire in sequence.2. Increase pulling force until dynamometer indicates between 5,500 and 6,000 lb. DO NOT EXCEED A PULLING FORCE OF 6,000 LB.3. If pulling force will not reach 5,500 lb, wire is broken. Remove in one piece and store against Inside wall of the tendon gallery. Record on Data Sheet 2 the maximum pulling force applied to the removed wire.4. If continuity is verified, blacken the appropriate circle in the anchor head sketch below.5. If wire is broken and removed, mark the appropriate circle with an 'X'6. If wire Is removed for a surveillance lest sample, mark the appropriate circle with a single slash.7. Identify the short lest wire with an arrow pointing to the appropriate circle.1-1 W, rco-wl'l Topical Report 204 Revion 0 Attachment 8.3 Page 10 of 18 Page 10 of 18 I 1129072-02 Attachment B TMI-1 2010 Augmented Tendon Survwlllnoce Wire Continuity Test Data Sheet 2 of 2 (Use for Verifying Continuity of Vertical Wires by Pulling a ph Bottom 1 End)Tendon Number I- Date,/o- o0-2 / Signature Dynamometer ID No. gI /Cal due Dale lkt-epj. / Accuracy Data Sheet 2 instructions:
- 1. On the ciagram below, Identify each removed wive by marking the appropriate circle wilh an X.2. For each wire removed, record the maximum applied pulling force adjacent to the anchor head Draw an arrow from the recorded force to the appropriate marked circle.64t, .,._.. ..... .."4_I-.4 k' W r o I A*Fe~ F '~"~4 *~6.- s ~Topical Report 204 Revlon 0 Attachment 8.3 Page 11 of 18 Page 11 of 18 1129072-02 Attachment C Exel n E P .LC Power LabsTeclh'ic Swvike Em 00-9T1-LARS 175 KatCai Road 610-380-2532 fax Cowevie, PA 19320-2309 Toi Evan Johnson, Three Mile Island Station From: R. John Diletto, (610)380-2427 john.diletto Project Number. TMI-18793
Subject:
Material and Failure Evaluaton of Two Wires in Tendon VN18 Found Protruding in the Upper Anchor Head, Oct 2010 Buttonhead Inspection Ref WO: R-2139507.
Three Mile Island Date: January 5. 2011 DESCRIPTION COMPONENT FAILURE & INITIAL INVESTIGATIONS:
Two comer wires were found not fully seated in the anchor head. The wires were pulled from tendon with little effort There are 169 wires per tendon, each approximately 1847 long. The anchor head. approximately 4" thick is hydraulically lfted and shlmmed to achieve a tensile stress of 830 of the tendon design maximum tensile strength.
No corrosion was reported during the inspection and removal.REQUESTED WORK AND SPECIAL INSTRUCTIONS:
The 0.25" diameter high strength steel wire samplesneed to be tested LAW ASTM A370 as specified in the wire spec ASTM A42 1. The analysis should also imnestigate the cause of the break CONCLUSIONS All tensile test results for Load It 1%6. Breaking Load & % Elongation, were in accordance with 0.2 50" diameter wire spec ASTM A42 Iacceptance criteria.The two V-1 18 broken wires had fiactured surfaces indicative of both sheanng forces and ductile overload Circumferential indentations and slight bending was observed adjacent both wire fractures.
most likely from where the wire exAs the anchor head. Thns location would be characterized.
as a geomxetrc stress riser as well as a source for shearing forces s.nergistic with the mechanical notch would sigaificantly contribute to premature wire failure.Another unconfirmed possible contributing factor would be if the overall effective wire length was slightly shorter than the others within the tendon. hence under a greater share of the total load.The Exelon PowerLabs Quality System meets 1OCFR$O Appendix B, 10CFR21, ANSI 345.2, A nSI/CSL Z540-1, and _NQA 1.Exelon PowerLabs is ISO 9001:2000 Registered (8734)and ISO/lEC 17025 Accredited (2044.01102).
Topical Report 204 Revion 0 Attachment 8.3 Page 12 of 18 Page 12 of 18 1129072-02 Attachment Cý V' TEST PLAIN 1. Photo document the as-recei-ed tendon wires.2. Perform tensile tests on each wre at the top, mid and lower segments.
Reference ASTM A412 for acceptance criteria 3. Perform Stereoscopic examination and photo documentation.
- 4. Perform electron microscopy exam on both fractures.
M MW--- STATEMENT OF QUALITY , Testing was performed with standard equipment that have accuracies traceable to nationally recognized standards, or to physical constants, by qualified personmel, and m accordance with the Exelon PowerLabs Quality Assurance Program.Technician(s):
Stephen Mer;aman.
(610)380-2472, stephen.merjaniaaneExelctnPoweLabs.com Reviewed by Approved by Stephen D. Meiyanian ANSI Level f ! Technician O0I04'2011 R. John Diletto Sr. MetallurgyMaterials Engineer 0104*2011 Projecr review and approval is electronically authenticated in Exelon PowerLabs project record cc: Fleet Dist Exelon PowerLabs, LLC Project Number: TMI-18793 Page 2 of 6 Topical Report 204 Revlon 0 Attachment 8.3 Page 13 of 18 Page 13 of 18 1129072-02 Attachment C OBSERVATION'S and DATA Figure L Photographs of the As-Rertdved V-118 Tendon Wires Nos. 1 and 2 V-1 18 Tendon Wire No. 1 The wire length No.46 fracture was located approximately 4" from the upper (roof) end and most likely where the wire exits the anchor head.Wire length No. 1 was at ground level and length No. 23 was approximately mid-length.V-11IS Tendon Wire NO. 2 The wfie length No.46 fracture was located approximately 4" from the upper (roof) end and most likely where the wire exits the anchor head.Wire length No. I was at ground level and length No. 23 was approximately mid-length.ExdrLn PowerLabsv,LLC Project Number: TMII-18793 Page 3 of 6 Topical Report 204 Revion 0 Attachment 8.3 Page 14 of 18 Page 14 of 18 1129072-02 Attachment C Figure I. Side & End View Photographs of the Fractured Tendon Wires Nos. 1 and 2 Wire Nos. I & 2 both exhibited circumferential scoring and lateral deformation adjacent the fracture suggestive of a shearing force. The arrows in the photos below denote the direction of fracture.Exelon PowerLabs9,LLC Project Number TMNI-18793 Page 4 of 6 Topical Report 204 Revion 0 Attachment 8.3 Page 15 of 18 Page 15 of 18 1129072-02 Attachment C Tensile Testing in accordance with ASTM A421 Load ýR 1% Breaking Load Final Gage % Elongation Wihe 1 Lbf Lbf. Inches 1 10,600 12.275 10.57 5.7%23 10,650 121275 10.55 5.5%45 10,500 12-150 10.60 6.0Me Wire 2 1 10.650 1'200 10.525 5.25%23 10,700 121175 10.540 5.45%45 10,775 12200 outside gage 45 re-do 10,750 12,150 10.50 5.0%Acceptance
>10,016 >11,784 >4.0%All tensile results were taw 0.250" diameter ware Figure M. Lab Notched Bending Fracture I A short wire length was horizontally positioned and the vise jaws were tightly closed vise to induce surface scoring. The wire was repositioned vertically and the free end was bent approximately 60-degrees when rapid fracture occurred.The fracture initiated at one of the surfaces indentations.
The fracture surface had a fibrous appearance.
characteristics of ductile overload accompanied by shear lips at both neutral quadrants.
There was no necking down as in the lab tensile overload test.Exel n PowerLabsS,LLC Project Number: TMI-18793 Page 5 of 6 Topical Report 204 Revion 0 Attachment 8.3 Page 16 of 18 Page 16 of 18 1129072-02 Attachment C Electron Microscopy Figure IV. Fractograpks of the Tendon Wires Nos. 1 and 2 and the Lab Fracture No. I Ball End Fracture The fracture appearance exhibited an aged ductile surface.Magnification:
IOOOX No. 2 Ball End Fracture The fracture appearance exhibited an aged ductile surface.Magnification:
IOOOX The tensile test fracture surface was as-expected for a ductile overload failure.Magnification:
1OOOX F-elxen LLC Project Number: TMI-18793 Page 6 of 6 Topical Report 204 Revion 0 Attachment 8.3 Page 17 of 18 Page 17 of 18 1129072-02 Attachment D Comparison of Tendon VI 18 Elongation Rates between SGRP Retensioning Assuming 169 and 167 effective wires and both ReTensionings during the 2010 Tendon Inspection 1800.00 1600.00 1400.00 LO 800.00 cn 1000.00 C 0'0 600.00 400.00 200.00 0.00 3.5 5.5 7.5 9.5 11.5 13.5 15.5 17.5 Reference Distance From Anchorhead or Coupler Face to the Bearing Plate (PTF,OSF)SGRP SGRP Tensioning Tensioning 2010 2010 (assuming 169 (assuming 167 Tensioning Tensioning effective wires) effective wires) 10/26 10/27# of Wires 169 167 166 166 PTF Force 199.20 199.20 195.81 195.81 kiop PTF Dist 3.8 3.8 5.0 4.5 inch OSF Force 1581.90 1581.90 1558.73 1558.73 kip OSF Dist 17.8 17.8 18.5 18.5 inch Diff Force 1382.70 1382.70 1362.92 1362.92 ki Diff Dist 14.0 14.0 13.5 14.0 inch Elong Rate 1.711 1.691 1.644 1.705 inch-wire/kip Elongation Rate % change from SGRP 169 Elongation Rate %change from SGRP 167 Elongation Rate %change from 10/26 3.909 2.758 0.350 0.844 3.704 The acceptance criterion for allowable change in elongation rate is <10% change from the last tensioning per IWL-322 1.1. The variations observed here are normal and expected.
The change in elongation rate from 10/26 to 10/27 can be explained as a re-distribution of the tendon's twist. The 169 wire bundle in the tendon duct has a twist to distribute the elongation of the wires more evenly when a tendon is routed through a curved duct. The twist distribution was altered when the wires were pulled individually and subsequent de- and re-tensioning will re-distribute the twist and result in a larger elongation rate as observed here. In this case, the vertical tendon VI 18 has no curvature in its duct and the wire twist is of little to no importance other than its effect on elongation rate.Topical Report 204 Revion 0 Attachment 8.3 Page 18 of 18 Page 18 of 18