ML091060762

04/07/09 Summary of Conference Call with Palisades Nuclear Plant Regarding the Spring 2009 Steam Generator Inspections

ML091060762
Person / Time
Site:	Palisades
Issue date:	05/07/2009
From:	Mahesh Chawla Plant Licensing Branch III
To:	Entergy Nuclear Operations
Chawla M, NRR/DORL, 415-8371
References
TAC ME0692
Download: ML091060762 (24)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 l"1ay 7, 2009 Vice President, Operations Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530

SUMMARY

OF CONFERENCE CALL WITH PALISADES NUCLEAR PLANT REGARDING THE SPRING 2009 STEAM GENERATOR INSPECTIONS (TAC NO. ME0692)

Dear Sir or Madam:

On April 3, 2009, and April 7, 2009, the Nuclear Regulatory Commission (NRC) staff participated in conference calls with representatives of Entergy Nuclear Operations, Inc. (the licensee) regarding the ongoing steam generator (SG) inspection activities at Palisades Nuclear Plant.

Based on the information provided by the licensee, the NRC staff did not identify any issues that warranted immediate follow up action. The NRC staff however, indicated that they will evaluate the need to review the eddy current data from the tube in R72C107 in SG B, to assess the significance of the 2007 and 2009 inspection data. A summary of the conference calls is attached as an enclosure. In case you have any further questions, please free to contact me at 301-415-8371 or Mahesh.chawla@nrc.gov.

Sincerely, Mahesh L. Chawla, Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-255

Enclosure:

Staff Evaluation cc w/encls: Distribution via ListServ

CONFERENCE CALL

SUMMARY

PALISADES NUCLEAR PLANT REGARDING SPRING 2009 STEAM GENERATOR INSPECTION RESULTS On April 3, 2009, and April 7, 2009, the staff of the Steam Generator Tube Integrity and Chemical Engineering Branch (CSGB) of the Division of Component Integrity (DCI) participated in conference calls with representatives of Entergy Nuclear Operations, Inc. (the licensee) regarding the ongoing steam generator (SG) inspection activities at Palisades Nuclear Plant.

Palisades Nuclear Plant has two Combustion Engineering Model 2530 replacement SGs.

Each SG has 8,219 mill-annealed, Alloy 600 tubes. The tubes have an outside diameter of 0.75 inches, and a wall thickness of 0.042 inches. Stainless steel, eggcrate, lattice-type tube supports, diagonal straps, and vertical straps support the tubes at various locations. The tubes were expanded through the full depth of the tubesheet using an explosive process.

Prior to the conference call, the licensee provided a written response to a set of discussion points from the NRC staff (Agencywide Document Access and Management System (ADAMS)

Accession No. ML090550826). The licensee's response is attached to this call summary.

Abbreviations used by the licensee in the attached document include:

• CL - Cold leg

• PID - Positive Identification

• DNG - Ding

• PLP - Potential loose part

• DNT - Dent * +Pt - Plus Point'

• ET - Eddy current testing

• PWSCC - Primary water stress corrosion cracking

• GPD - Gallons per day

• REFOUT - Refueling outage

• Hist - Historical

• RPC - Rotating pancake coil

• HL - Hot leg

• RxCx - Row x Column x

• ID - Inside diameter

• SCC - Stress corrosion cracking

• ips - inches per second

• SG - Steam generator

• ISPT - In-situ pressure testing

• SI - Special interest

• kHz - kilohertz

• SVI - Single volumetric indication

• MBM - Manufacturing burnish mark

• TW - Through wall

• ODSCC - Outside diameter stress

• V - Volts corrosion cracking

• Pct - Percent Additional clarifying information and information not included in the attached document is summarized below.

The tube with axial PWSCC in the U-bend, located in R2C57 of SG B, had a signal amplitude of approximately 1.68 volts, a length of 0.31 inches, and a depth of approximately 70 percent through wall. The licensee indicated that this indication has not changed for the last couple of outages, it may not be a flaw, and it does not exceed the in-situ screening criteria.

Enclosure

-2 The U-bend sections of the low-row tubes that were inspected had noise levels less than that contained in the examination technique specification sheet. One tube in the attached document was mislabeled. Under the fourth bullet of discussion point 8, the tube labeled as SG E-50A R17C4 should actually be SG E-50A R19C4.

No batwing visual inspections were performed during this outage as they have been performed the previous three outages and no movement has been identified. The bobbin coil data were reviewed for indications of batwing movement and no movement was noted. Palisades has not performed chemical cleaning (which may have contributed to the batwing displacement at another plant).

The increase in the primary-to-secondary leak rate at the end (March 2009) of the attached primary-to-secondary leakage graph is associated with a forced shut down that occurred near the end of the operating cycle. The spikes in May and August of 2008 were also associated with plant shutdowns.

No crack-like indications were associated with dents or dings (at the time of the call).

The licensee indicated that free span crack-like indications detected in prior outages were primarily associated with anomalies on the tubes outside surface (e.g., dings or scratches ).

The NRC staff asked to be notified if any indications were found during the remainder of the inspection that would require in-situ pressure testing or were located in the free span.

In addition, the !\IRC staff asked for copies of the terrain plots for the PWSCC flaw in the U-bend region and the axially oriented ODSCC indication near the TTS (see attached).

The licensee notified the NRC staff on April 6, 2009, that an axial crack-like indication was identified in SG B at the first hot-leg tube support that satisfied the in-situ screening criteria. The indication was in the tube at R72C1 07 and was approximately 1 inch long with a depth of approximately 60 percent through wall. A brief summary of the indication was provided by the licensee (see attached). The in-situ pressure test was performed on April 6, 2009, and a follow-up conference call was held with the NRC staff on April 7, 2009.

In preparation for the conference call, the licensee provided a summary of the results of the in-situ pressure test (e.g., no leakage at a pressure of 5500 psi). This summary is attached. The NRC staff acknowledged that the tube passed the in-situ pressure test, but questioned the basis for the sizing technique and the potential for similar, or larger, indications to be identified in future inspections and which may be in tubes with less favorable material properties.

The licensee indicated that the flaw in this tube was conservatively sized using a technique optimized for sizing flaws in tubes with a radius to wall-thickness ratio different than is present in the Palisades' steam generators. The licensee further indicated that when a sizing technique more appropriate for the tube size at Palisades (i.e., 3/4-inch diameter tubes) is used, the maximum depth of the flaw is 48 percent through-wall (instead of 63 percent). These sizing techniques were based on Westinghouse

- 3 evaluation of pulled tube data. The licensee also indicated that based on hindsight, an indication was present at this location in 2007. When the more appropriate sizing technique was used, the indication (in the 2007 data) was estimated to be approximately 35 percent through-wall. The licensee indicated that the flaw in the 2007 data would normally not be called. There were approximately 10 to 12 flaws detected at the eggcrate elevations in the 2009 outage. Many of these indications were located at the lower (Le., hotter) tube support elevations. The licensee also indicated that the eddy current data analysts were trained to detect indications at the eggcrate elevations and that the indication in R72C1 07 was detected with the bobbin coil.

Based on the information provided by the licensee, the NRC staff did not identify any issues that warranted immediate follow up action; however, the NRC staff indicated that they will evaluate the need to review the eddy current data from the tube in R72C107 in SG B, to assess the significance of the 2007 and 2009 inspection data.

PRELIMINARY INFORMATION STEAM GENERATOR TUBE INSPECTION DISCUSSION DURING PALISADES 2009 (1R20) OUTAGE

1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

Refer to attached Primary to Secondary Leak Rate for Operational Cycle 20 Primary to Secondary Leak Rate graph.

2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.

No secondary side pressure tests were performed in the 2009 refueling outage (1 R20).

3. Discuss any exceptions taken to the industry guidelines.

No exceptions were taken to industry guidelines in the 2009 refueling outage.

4. For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100% of dents/dings greater than 5 volts and a 20% sample between 2 and 5 volts), and the expansion criteria.

Refer to attached Table 4-2 Palisades REFOUT 20 SG Eddy Current Inspection Scope for a description of inspections performed, expansion criteria and a description of the probe used for the inspections performed.

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc.), provide a summary of the number of indications identified to-date of each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications at the expansion transition). For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

This response is based on eddy current data collected and analyzed as of 9:45, April 3,

2009, Attachment

-2 Tubesheet Region +Pt Program:

SG E-50A Seven (7) tubes with axial OOSCC in sludge pile region SG E-50B Two (2) tubes with axial OOSCC in sludge pile region.

No tubes with circumferential OOSCC in either SG.

Most significant indication is 0.70V from +Pt in 300 kHz channel (70%TW). Longest length reported from resolution analysis is 0.38 inch (different indication). Indication length from profile for this (0.38 inch by resolution) indication is 0.33 inch.

SG E-50A Three (3) tubes with circumferential PWSCC indications, one (1) with axial PWSCC all in tubesheet.

SG E-50B No tubes with PWSCC in tubesheet.

Oeepest depth of eire indications is 48%TW, longest arc length is 37 degrees. Sing[l]e axial PWSCC indication is estimated at 53%TW with a length of 0.14 inch.

SG E-50A One (1) tube reported to contain a shallow volumetric signal associated with a loose part at R19 C4. Such indications often are false reports and are not observed when the object is removed.

Tube Supports:

+Pt confirmation testing of bobbin signals at support locations is not complete. No indications reported to date.

SG E-50A Two (2) tubes with a wear signal exceeding the 40% repair criteria.

SG E-50B Two (2) tubes with a wear signal exceeding the 40% repair criteria.

Reported depths are 40 to 42%TW and growths range from 3 to 8% for Cycle 20.

SG E-50B One (1) tube with axial PWSCC in U-bend tube R2C57.

SG E-50A No tubes with PWSCC in U-bend Freespan:

+Pt confirmation testing of bobbin signals in freespan has not started.

Tube structural and leakage integrity was maintained during Cycle 20 based on observed relatively minor flaw parameters reported for REFOUT 20. Two sludge pile axial OOSCC indications exceed the ISPT initial screening value of 0.50 volt. Lengths from profile analysis are 0.24 and 0.33 inch, less than the 100%TW critical flaw length of 0.39 inch. The 100%TW structural limit length is developed at a lower 95%

probability. All +Pt signal amplitudes for stress corrosion cracking are below the ISPT screening values for leakage assessment.

-3

6. Describe repair/plugging plans.

Currently there are 14 potential tubes requiring tube plugging in SG E-50A and 5 potential tubes in SG E-50B.

All stress corrosion cracking (SCC) indications will be plugged. Any circumferential SCC indications near top of tubesheet (TTS) will be stabilized and plugged.

All structure wear greater than or equal to 40%TW will be plugged.

7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).

Based on the available data to date, no tubes require in-situ pressure testing.

8. Discuss the following regarding loose parts:

• What inspections are performed to detect loose parts?

The hot leg top of tubesheet (TTS) region is inspected with +Pt up to 3 inches above TIS. A similar inspection is performed for the cold leg TTS region (3 tubes deep along periphery and tube lane). Foreign object search and retrieval (FOSAR) is performed for the periphery, tube lane annulus, and stay cavity areas.

• A description of any loose parts detected and their location within the SG Foreign object search and retrieval (FOSAR) scheduled for 2 loose parts in contact with the following steam generator tubes:

SG E-50A R17C4, R18C3, R18C5, R19C4 (SVI) loose at tubesheet SG E-50A R59C156, R61 C156 loose part 12 inches above tubesheet

• If the loose parts were removed from the SG FOSAR is scheduled in SG E-50A for 4/6/2009 and in SG E-50B on 4/7/2009.

• Indications of tube damage associated with the loose parts One tube in SG E-50A R~[19] C4 is reported to contain a small volumetric signal (SVI) at approximately 2 inches above TTS. This location is on the hot leg periphery. Bobbin analysis reported a non quantifiable indication (NOI) signal and confirmed with plus point. FOSAR will examine the area and if possible the part will be removed. Depth of the wear is estimated to be less than 5%. If unable to remove, the tube will be plugged and stabilized and the surrounding tubes evaluated for repair.

- 4

9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessment deposit loading, etc.).

Visual inspection scheduled both SG E-50A and SG E-50B tubesheet periphery regions and in bundle top of hot and cold leg tubesheets, foreign object search and retrieval (FOSAR) scheduled for 2 loose parts in contact with the following steam generator tubes:

SG E-50A R17C4, R18C3, R18C5, R19C4 (SVI) loose at tubesheet SG E-50A R59C156, R61 C156 loose part 12 inches above tubesheet

10. Discuss any unexpected or unusual results.

CR-PLP-2009-01440 Loose Part on Primary Side Tube in SG E-50B initiated. During routine inspections of the steam generators for 1R20, an obstruction has been identified in SGB HL tubesheet in tube Row 23 Column 8. The obstruction is foreign material that is preventing the eddy current probe from passing through the tube. The object was lodged on the 10 of the tube approximately 1.5 inches from the tube end on the hot leg side. The object has been successfully removed from the tube and is currently on the bottom of the steam generator bowl. An extraction plan for this loose part is being developed.

CR-PLP-2009-01448 Loose Part on Secondary Side Tube in SG E-50B initiated.

Steam Generator E-50A Eddy Current Inspection Identifies Loose Part. The loose part was identi'fied in Steam Generator E-50A hot leg top of tubesheet. It is in contact with 4 tubes, 1 of which may have loose part wear. The tube with wear is in Row 19 Column 4. The loose part is approximately 3 inches in length.

CR-PLP-2009-01657 Steam Generator ET Inspection Identifies New Damage Mechanism initiated. Steam Generator E-50A has identified a new damage mechanism which is circumferential primary water stress corrosion cracking (PWSCC) in the tubesheet. Circumferential PWSCC in expanded tube in tubesheet was identified as a potential mechanism by steam generator degradation assessment for 1R20. Three tubes are affected in SGA, none in SGB. Indication depth is shallow and indication arc lengths are short <<40 degrees).

CR-PLP-2009-1564 Steam Generator ET Inspection Identifies Defective Tubes. Steam Generator E-50A and E-50B eddy current analysis has indicated tubes requiring repair by tube plugging. The damage mechanisms for the defective tubes are 40%

throughwall wear at support structures, axial outside diameter stress corrosion cracking (ODSCC) at the top of the hot leg in the expansion transition zone, volumetric ODSCC at the top of the hot leg tubesheet for loose part wear and axial and circumferential primary water stress corrosion cracking (PWSCC) in the tubesheet and U-bends.

Currently there is no expansion of scope required per Technical Specifications

-5 (TS) 5.5.8 and EPRI PWR Steam Generator Examination Guidelines: Revision 7 (EPRI Rev 7 lSI Guidelines).

11. Provide the schedule for steam generator-related activities during the remainder of the current outage.

Currently bobbin and top of tubesheet +Pt RPC are essentially complete in both steam generators. Special interest is in progress and will be completed this weekend in both steam generators (this includes dings/dents, u-bend, cold leg top of tubesheet etc.).

SG E-50 A and B foreign object search and retrieval (FOSAR) will also be started early next week. Tube plugging will also occur early next week.

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Table 4-2. Summary of SG Tube Degradation Mechanisms and Inspection Requirements: Palisades REFOUT 20 Degradation Location Probe Type Detection Inspection/Expansion Plan Mechanism Inspection Sample Plan Expansion Plan Existing Degradation Mechanisms Tube Wear Non dented Tube Bobbin 100% vertical straight length Rows 1 thru N/A Support Structures 3, 100% full length Rows 4 and higher, both SGs AxialODSCC Non dented Tube Bobbin 100% vertical straight length Rows 1 thru N/A Support Structures 3, 100% full length Rows 4 and higher, both SGs Plus Point 100% all DSI or %TW signals at 100% historical wear sites not eggcrates, 100% newly reported bobbin sampled in 1R20 siqnals between DBH and DBC inclusive AxialODSCC Freespan, Bobbin 100% vertical straight length Rows 1 thru N/A Freespan dings 3, 100% full length Rows 4 and higher,

<5V both SGs Plus Point 100% all bobbin I-codes N/A AxialODSCC Freespan dings Plus Point 100% dings >5V in both SGs, all N/A

>5V elevations and locations AxialODSCC Dented eggcrates, Plus Point 100% dented eggcrates, diagonal bars, N/A diagonal bars, vertical straps >2V vertical straps >2V Circumferenti HL TTS expansion Plus Point 100% from 3" above to 12.5" below See Note (1).

al and Axial transition and expansion transition, both SGs ODSCC sludge pile Axial PWSCC HL TTS expansion Plus Point 100% from 3" above to 12.5" below See Note (1) transition and expansion transition, both SGs expanded tubesheet

Table 4-2. Summary of SG Tube Degradation Mechanisms and Inspection Requirements: Palisades REFOUT 20 Degradation Location Probe Type Detection Inspection/Expansion Plan Mechanism Inspection Sample Plan Expansion Plan Axial PWSCC Row 1, 2, and 3 Plus Point 100% Row 1, 2, and 3 U-bends using mid 100% of Row 4 for indication in Row U-bends range coil (2) 3. Redefine plan if indications detected in Row 4.

Tube Wear Dented Vertical Bobbin: 100% vertical straight length Rows 1 thru N/A Straps. Diagonal 0.610" 3, 100% full length Rows 4 and higher, Bars and diameter both SGs (active mechanism dictates Eggcrates, <5V plan)

Dented Vertical Plus Point: 100% >2V dents will be performed as part N/A Straps, Diagonal 0.610"/0.580" of ODSCC inspection plan Bars and diameter Eggcrates, >5V Tube Wear Square bend Bobbin 100% vertical straight length Rows 1 thru N/A (freespan) region 3, 100% full length Rows 4 and higher, both SGs (active mechanism dictates plan)

Plus Point Highest eggcrate through square bend, N/A tubes surroundinq R99 C140 in SG B Tube Wear TTS periphery, Bobbin 100% full length bobbin +FOSAR in both Plus Point all surrounding tubes with (loose parts) tube lane SGs loose part or loose part wear signals Plus Point 100% hot leg TTS region plus 3 tube deep Plus Point all surrounding tubes with on cold leg periphery from 2" above to 2" loose part or loose part wear signals below TTS, plus special interest testing of PLP signals from bobbin in freespan, at eggcrates, and vertical straps, diagonal bars Resolution for Classification of Indications

Table 4-2. Summary of SG Tube Degradation Mechanisms and Inspection Requirements: Palisades REFOUT 20 Degradation Location Probe Type Detection Inspection/Expansion Plan Mechanism Inspection Sample Plan Expansion Plan Potential All Bobbin 100% vertical straight length Rows 1 thru N/A MBMs 3, 100% full length Rows 4 and higher, both SGs Plus Point Flaw confirmation of bobbin indications Review specific occurrences of flaw with change or no history detection and establish expansion plan based on observed parameters To Be Defined Bobbin Signals at Plus Point 25% historical DB and VS wear sites 100% DB and VS wear sites in both Suspected Wear SGs for detection of ODSCC Sites not yet characterized Potential Degradation Mechanisms Circ PWSCC Row 1and 2 Plus Point 100% Row 1, 2, and 3 U-bends in both 100% of Row 4 for indication in Row U-bends in both SGs using mid-range coil (2) 3. Redefine plan if indications SGs detected in Row 4.

Circ PWSCC HL TTS expansion Plus Point 100% from 3" above to 12.5" below See Note (1).

transition and expansion transition, both SGs expanded tubesheet Circ ODSCC Dented Vertical Plus Point Controlled by inspection requirements for 100% all dings/dents for confirmation Strap Locations existing or potential mechanisms, PLUS of eire ODSCC tube locations listed in Section 4.5, item 5 Pitting Sludge pile Bobbin Controlled by inspection requirements for N/A existing or potential mechanisms Non-Relevant Degradation Mechanisms Included in the REFOUT 20 Eddy Current Inspection Scope Axial PWSCC Dented support Plus Point Controlled by inspection requirements for 100% all dings/dents for confirmation structures existing or potential mechanisms of axial PWSCC

Table 4-2. Summary of SG Tube Degradation Mechanisms and Inspection Requirements: Palisades REFOUT 20 Degradation Location Probe Type Detection Inspection/Expansion Plan Mechanism Inspection Sample Plan Expansion Plan Axial and Circ Cold Leg Plus Point 3 tubes deep on cold leg periphery from 2" 100% cold leg from 2" above to 13 PWSCC expanded tube in above to 2" below TTS (controlled by inches below TTS tubesheet loose part detection proqrarn)

AxialODSCC Wear sites Bobbin Controlled by inspection requirements for N/A existing or potential mechanisms Plus Point 25% historical wear sites between DBH 100% all wear sites between DBH and and DBC DBC for confirmation of combined mode axial ODSCC + wear scar (1): 20% cold leg TTS Plus Point expansion at either REFOUT 20 or REFOUT 21 from 3" above to 12.5" below bottom of expansion transition in SG with C-3 condition or if failure of performance criteria at TTS is determined.

(2): Any Row 1 or Row 2 U-bend with mid-range +Pt coil noise exceeding the value specified in Appendix B will be tested with a high frequency +Pt coil probe.

Palisades Unitl REFOUT 20 March 2009 St"am G"n"rator Eddy currant Status GWestinghouse 51G 8'SSc9IF E. ,m ! w E EX6I1T1t E........

Prog-urT1l'll:ld AcqLired R_. An_

O~iIIminu

& Corf1JIete Al;qlired I Corf1JIete A CL Bobbin Full Length 48ips 7450 7388 0 7388 9917% 99,17%

A CL Bobbin C!V"dy Cane 40ips 179 179 0 179 100,00% 10000%

A CL Bobbin Straight 40ips 174 174 0 174 100 00% 100,00%

A CL ...PT Top 01 Tube-sheet 880 880 0 880 100,00% 10000%

A CL ...PT 51 P re...ous tndicsnons 351 0 0 0 000% 000%

A CL ...PT 51 US Pre ...ous rnccetons 831 0 0 0 000% 000%

A CL ...PT 51 UB Pc t 25% HI~ Sl!lImple 81 0 0 0 000% 000%

A HL Bobbin straight 40ips 353 353 0 353 100,00% 10000%

A HL ...PT Top 01Tube-sheet 7803 7751 1 7750 99,32% 9932%

A HL ...PT Row1-3 U-Elend '74 174 0 174 100,00% 10000%

A HL ...PT 51 Pre ....o usmctcetons 601 227 0 29 3777% 483%

A HL ...PT 51 UB Pre-"ous Indications 180 140 3 93 7611% 5167%

A HL ...PT 51 UB ec t 25% Hi~ Sl!lIl1'Iple 48 45 0 27 9375% 5625%

Tolel Tests.Al1 Programs 19105 17311

• 170.7 9059% I 89.23%

CL Bobbin fUll Length 48ips 7480 7445 3 7442 9949% 9949%

CL Bobbin Candy CI!lIn6 40ips 179 179 '2 167 93 30'% 9330%

CL 80bbin straigtrt 40ips 177 177 0 177 , 0000% 1000Cl'%

CL ...PT Top of Tubesheel 891 891 0 891 , 00 00% 10000%

CL ...PT 51 P revous Indications 212 0 0 0 000% 000%

CL ...PT 51 U8 Prevoustnccetone 382 0 0 0 000% 000%

CL ...PT 51U8 PCT 25% Hist Sample 76 0 0 0 000% 000%

HL HL 80bbin stmight 40ips

...PT Top 01 tucesneet 356 7636 356 7765 ,

0 356 7764 10000%

9934%

10000%

99,34%

HL ...PT Row1-3 U-Bend 177 177 5 172 9718% 9718%

HL ...PT SI P revous Indications 369 162 0 0 4390% 000%

HL ...PT SI U8 crevousrnccetone 172 '65 0 102 9593% 5930%

HL ...PT SI U8 PCT 25% Hist Sample 54 54 1 36 9815% 6667%

R_. An_

Talel Tess,a,1 Programs 18363 17391 22 17127 94.59% I 93.27%

EXiIIlTIt E...... Olltstandng l\ l\

Seesl'! Intlfe!t Adclt1ma! SC ooe Prog-ernTll:ld Al;qured & Corf1'ele Al;ql.ired I ColT1Jlde A

A HL ...PT 51 Newtndcencns HL ...PT 51 U8 Newtndcenons 1

0 1

0 0

0 0

0,00%

100,00%

0,00%

000%

A HL ...PT ONT.oONGiPCTSI NevvindiCfllions 11' 0 0 0 000% 0,00%

A HL ...PT ONT.oONGiPCTSI U8 NfN\Ilndlcalions 51 42 0 14 8235% 27.45%

A HL ...PT RetesWth Volume S1d 1 0 0 0 0,00% 0,00%

A A

CL ...PT SI Newrnccetcns CL ...PT SI U8 Newtncceucns 8

3 5

0 0

0 0

62.50%

0.00%

50,00%

000%

A CL ...PT DNT.oONGJPCT 51 Newlndicalions 127 52 0 9 40,94% 708%

A CL ...PT DNT.oONGiPCT 51U8 NfN\IlndicallOl1S 43 0 0 0 000% 000%

A Retest 'Mh Volume51d 1 0 0 0 000% 000%

A PLP ...PT 4 0 0 0 0.00% 000%

A Mag Btes Rete:sl 0 0 0 0 000% 000%

A PID 80bbln 2 0 0 0 000% 000%

A PIO ...PT 12 0 0 0 000% 000%

Total Tests.Lij1Programs JOO tuu U " 1 ,... I ' J ....

HL ...PT 51 Newtndcetcns HL ...PT SI U8 Newtnecencns 7

1 ,

0 0 0

0 1

000%

10000%

000%

10000%

HL ...PT DNTiONGiPCT SI Newtrcrcetrons 126 0 0 0 000% 000%

HL +PT DNTiONGJNewPCT 51 U8 Newtnocencns 68 87 1 50 9773% 56,82%

HL ...PT Retest VVi1h Volume Std 0 0 0 0 000% 000%

CL ~PT 51 Newtnocetrons 5 3 0 0 6000% 000%

CL +PT 51U8 Newtnocetroos 3 0 0 0 000% 000%

CL +PT DNT/ONGiPCT 51 Newtncacenons '01 57 0 0 5644% 000%

CL ...PT DNT/ONGJPCT $I Us NfN\Ilndicatlons 48 0 0 0 000% 000%

Retest 'Mh Volume 51d 0 0 0 0 000% 000%

P LP +PT 0 0 0 0 000'% 000%

Mag Bias Retesl 0 0 0 0 000% 0,00%

P 10 80bbln 2 0 0 0 0,00% 000%

PID ...PT 2 0 0 0 000% 000%

Total Tests,a,1 Programs 30' 148 1 51 '838% 13.32%

ADDITIONAL ,"FORMATDN

~

RgrJr8t:,Wd'!rt1!.. 40%, ",PT I-Codes) ~

• IliIL 19 CONF'Rr.ED PLUGGABLE TUBES FOB RFOUPO Confirmld Tubes to be Plumed 5IGA 51G *

-0 ~

Repair CandlMte (->40%, +PT I-Codes) 0 Preventative Tube Plug *EC Results 0 0 0 T01" NWiI ptugs 0 0 0 Prior Plugs 416 3.3 199 Total Cornritted Plu 416 383 799 Weitinghouw Eledric Co STMal< Data as 019:46 AM on 4t.l12009

PCRS Condition Summaty CR-PLP-2009-01717 PCRS WebLink This report contains only summary information. Please consult PCRS application for full detail.

Discovered date/time: 4/4/2009 1:29:50 PM CR Status: Open Originated By: Meatheany,Danief J ( Eng P&C Code Program Staff ANO ) Responsible Dept: Eng Programs Mgmt PLP Operability: NOT REQUIRED Classification: CORRECT/ADDRESS Reportability: Significance: C Affected Systems: Affected Equipment:

Condition

Description:

During the 1R20 steam generator inspection, a flaw (axial crack) was identified in SG-E-50B (SGB). The location of the flaw is at the 01Hot tube support plate. Based on the size and dimensions (- 1 inch long and 60% throughwall deep) of the flaw, it will require in-situ testing.

Per the steam generator program, testing is required. If the flaw were to fail its performance criteria, it has implications in both maintenance rule and technical specifications. The current limit for palisades is 3 times the normal operating delta pressure (3DP) which is equal to 4100 psi. The calculated value for this flaw is - 3600 psi. It should be noted that this calculation is performed with high degree of uncertainty so is typically conservative. The best estimate is closer to - 6000 psi. This should be classified as a heat up restraint for the outage. The generators are currently considered inoperable and should remain that way until this condition is evaluated.

Immediate Action

Description:

Perform all required additional eddy current testing prior to In-situ testing - Complete Mobilize the equipment and personnel from Waltz Mill ASAP Initiate a scope add for cost, dose and budget consideration Suggested Action

Description:

Perform pressure testing in accordance with approved procedures and determine if the tube met its performance criteria. Notify the NRC Corrective Actions:

No Corrective action has been issued for this CR.

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White Paper on In-situ Tube at Palisades During 1R20 04/05/2009 This report documents the details associated with an axial outer diameter stress corrosion cracking (ODSCC) indication on tube Row 72 Column 107 (R72C107) in SGB at Palisades. During the 1R20 inspection, an axial ODSCC indication was identified at the 01 Hot (01 H) tube support plate. The tube support structure is a series of stainless steel straps that consist of two 2 inch straps and two 1 inch straps that intersect to form a diamond shape hole in which the tube resides.

The indication was initially reported by the bobbin probe, which is a screening probe; 100% of the tubing was tested full length. A subsequent test is performed using the plus point coil, which is used to confirm the characterization of the bobbin coil signal. The plus point coil gives a three dimensional aspect to the flaw and allows the analyst to assign a detailed depth, length and width to the flaw. A third inspection was performed with a Ghent probe. The Ghent probe can provide additional clarification data of the signal if interferences associated with the complexity of the support structure and deposit conditions are thought to influence the plus point signal characterization. The Ghent probe confirmed the indication as axial ODSCC. Lastly, the tube was tested a second time with the plus point coil to perform a positive identification (PI D), which validates the correct tube has the flaw for repair.

The details associated with the flaw developed from the 2009 plus point data are as follows:

Length 1.01 inches Maximum Depth 63%

Average Depth 55.7%

SG tube integrity is governed by the plant technical specifications, utility adherence with NEI 97-06, and EPRI integrity assessment guidelines. Per these documents, any observed indications must satisfy a burst requirement of three times normal operating pressure differential. For Palisades this value is 4100 psi.

A burst pressure is calculated using a program that allows the user to input a variety of variables and results in a burst pressure with a 95/50 probability/confidence. This is required by the guidelines. The calculated burst pressure using this method was

- 3600 psi which is below the limit of 4100 psi. This value is very conservative. The integrity engineer also calculated a "best estimate" burst pressure using the average values for inputs. This value was - 6000 psi. As the calculated burst pressure is less than the performance criterion of 4100 psi, an in situ pressure test is required in order to show compliance with technical specifications and EPRI guidelines. As the performance criterion is based on operating conditions and the in situ pressure test is performed at room temperature, the test pressure is adjusted to account for material property changes due to temperature difference. The temperature adjusted in situ proof test pressure is 4455 psi.

We will re-test with eddy current after the in-situ test has been performed.

Results of the In-situ Test at Palisades During 1R20 04/06/2009 During the 1R20 steam generator inspection, a tube in SG-E-50B (SGB) (R72C107) was identified as having a single axial indication at the 01Hot tube support intersection.

The dimensions of the flaw and estimated depth from amplitude based sizing were:

Length: 1.01" Maximum Depth: 63%

Average Depth: 55.7%

Vpp e.62 I

OEG 113 SRI The in-situ pressure test was performed on 04/06/2009. The tube was screened based on amplitude sizing which is conservative as compared to phase based sizing. The test was conducted in accordance with the EPRI Guidelines. A localized tool was used to perform the test. The test was performed in a leak mode for all test pressures, that is, the proof bladder was not used for the proof test pressure (~ 3800 psi). The results of the test were zero leakage and no burst. Testing pressures which included offsets for temperature and instrumentation uncertainty were:

Normal Delta Pressure (NODP) 1500 Intermediate Pressure 2250 Steam Line Break Pressure 2800 Intermediate Pressure 3800 3NODP 4450

500 psig above 3NODP 5000 1000 psig above 3NODP 5500 The elevated pressure above 3NODP was performed in an effort to quantify the sizing uncertainties associated with calculating burst pressures.

Post RPC data was performed following the in-situ test. The results of that testing indicated no significant change in the flaw characteristics. The volts peak to peak increased from 0.49 to 0.79 volts. Listed below is the terrain map of the post in-situ test with the plus point:

Vpp 0.79 OEG 169 SRI No other in-situ testing was required.

May 7,2009 Vice President, Operations Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530 SUB~IECT:

SUMMARY

OF CONFERENCE CALL WITH PALISADES NUCLEAR PLANT REGARDING THE SPRING 2009 STEAM GENERATOR INSPECTIONS (TAC NO. ME0692)

Dear Sir or Madam:

On April 3, 2009, and April 7,2009, the Nuclear Regulatory Commission (NRC) staff participated in conference calls with representatives of Entergy Nuclear Operations, Inc. (the licensee) regarding the ongoing steam generator (SG) inspection activities at Palisades Nuclear Plant.

Based on the information provided by the licensee, the NRC staff did not identify any issues that warranted immediate follow up action. The NRC staff however, indicated that they will evaluate the need to review the eddy current data from the tube in R72C1 07 in SG B, to assess the significance of the 2007 and 2009 inspection data. A summary of the conference calls is attached as an enclosure. In case you have any further questions, please free to contact me at 301-415-8371 or Mahesh.chawla@nrc.gov.

Sincerely, Ira!

Mahesh L. Chawla, Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-255

Enclosure:

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PUBLIC LPL3-1 rtf RidsAcrsAcnw_MailCTR Resource RidsNrrLABTully Resource RidsNrrDirsltsb Resource RidsNrrDorlDpr Resource KKarwoski. NRR RidsNrrDorlLpl3-1 Resource RidsNrrPMPalisades Resource MYoder. NRR RidsRgn3MailCenter Resource RidsOgcRp Resource ADAMS Accession No ML091060762 *Memo dated 4/9/09 from M Yoder to L James OFFICE LPL3-1/PM LPL3-1/LA NRR/DCI/BC* LPL3-1/BC NAME MChawla BTuily MYoder LJames DATE 05/06/09 05/06/09 04/09/09 05/07/09 OFFICIAL RECORD COpy