ML15294A297

Steam Generator Tube Inspection Discussion During Palisades 2015 (RF24) Outage (Preliminary Information)

ML15294A297
Person / Time
Site:	Palisades
Issue date:	10/27/2015
From:	Plant Licensing Branch III
To:	Entergy Nuclear Operations
Rankin J, NRR/DORL/LPLIII-1
References
CAC MF6993
Download: ML15294A297 (12)

Text

H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a STEAM GENERATOR TUBE INSPECTION DISCUSSION DURING PALISADES 2015 (RF24) OUTAGE (Preliminary Information)

Currently Palisades is ~ 80% through the base scope eddy current inspection and starting the special interest as of 10/1/2015 at ~ 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br />

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 24 Primary to Secondary Leak Rate graph. Leakage has been minimal all cycle.

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

No secondary side pressure tests are planned for the 2015 refueling outage (RF24).

3. Discuss any exceptions taken to the industry guidelines.

In cycle (22) Palisades submitted a deviation to the NRC: Technical Justification Supporting Deviation from the EPRI Appendix I ETSS for ODSCC Sizing Palisades will deviate from the "needed" requirement to use an approved Examination Technique Specification Sheet (ETSS) contained in The EPRI PWR Steam Generator Examination Guidelines - Revision 7, Section 6.2 for ODSCC sizing. Palisades will instead use a modified ETSS for ODSCC. The modified ETSS will be identical to the ETSS approved per Appendix I of the examination guidelines with the exception that only the sub-set of data from CE plants will be used instead of the combined fleet data set used in the approved ETSS.

A comprehensive review of axial ODSCC in Palisades steam generators shows that Appendix I28432 over sizes maximum depth values for axial ODSCC at Palisades. There is a reasonable basis to submit a deviation request for maximum depth sizing of axial ODSCC indications at Palisades. The request is relatively modest since it uses the Combustion Engineering (CE) subset of the well vetted data of Appendix I28432. The regression slope and standard error of regression are retained. Only the intercept parameter is changed. This provides an across the board reduction of NDE maximum depth sizing of 11.23 %TW.

This will lead to about a 1000 psi increase in calculated condition monitoring burst pressures and much better matching of projected and measured NDE maximum depths.

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H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a The deviation was implemented in the 2012 (1R22) refueling outage steam generator inspection for the remaining life of the existing Palisade steam generators.

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.

• Full length ECT bobbin coil examination of all in-service tubes (except row 1, 2, and 3 U-bends) in both SGs.

ECT +Point' coil examinations (both SGs):

• 100% of rows 1, 2, and 3 U-bends.

• 100% of hot leg from TTS + 3 to a minimum of 13.5 below the bottom of the expansion transition.

• 100% of free span dings >5V between TSH and TSC.

• 100% of >2V dents at egg crate, diagonal bar, and vertical strap intersections between TSH and TSC.

• 25% of historical %TW calls at diagonal bars and vertical straps

• 100% of historical TRA indications

• The outer 3 peripheral tubes at the cold leg from TTS+3 to TTS-2 for detection of possible loose parts or wear signals.

• The periphery region is defined to be the outer three (3) tubes exposed to the annulus, all tubes in rows 1 through 4, and the inner three (3) tubes around the stay cylinder region.

The expansion criteria for each degradation is attached to the back in tables 9-1 through 9-4.

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).

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H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a As of 10/1/2015 @ 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> Number Number Integrity SG Location Type Indications Tubes Acceptable Axial A TSH ODSCC 6 6 YES*

Axial A TSH PWSCC 0 0 N/A Circ A TSH PWSCC 0 0 N/A Circ A TSH ODSCC 1 1 YES*

A TSH Volumetric 2 2 YES*

A TEC to TEH Wear > 40 0 0 N/A Axial B TSH ODSCC 4 4 YES*

Axial B TSH PWSCC 0 0 N/A Circ B TSH PWSCC 0 0 N/A Circ B TSH ODSCC 0 0 N/A B TSH Volumetric 0 0 N/A B TEH to TEC Wear > 40 0 0 N/A Tube Axial A Supports ODSCC 0 0 N/A Axial A Freespan ODSCC 0 0 N/A Tube Axial B Supports ODSCC 0 0 N/A Axial B Freespan ODSCC 0 0 N/A

• Expectation based on voltage and sizing performed to date SG A

• 6 OD SAIs, all at TTS sludge pile on hot side (TSH+0.3 to 1.16) (see plot)

• 1 OD SCI, at TSH 3

H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a o 0.83 V o Max circumferential extent 0.38 (62 degrees) o Max depth 83 %TW o Not structurally challenging o No depth profile sizing yet

• 2 foreign object wear flaws (SVIs) o No sizing yet.

o We will attempt to remove the object, and then size them.

SG B

• 4 OD SAIs, all at TTS sludge pile on hot side (TSH+0.43 to 1.27) o Voltages are less limiting than the 3 largest in SG A.

o No sizing yet.

• No foreign object wear Both SGs - Support Structure Wear

• No plugging expected

• Average growth rate is essentially zero

• 95/50 growth rate is ~3 %TW/EFPY Freespan There is no free span repairable indications reported to date.

U-Bends There are no U-bend repairable indications reported to date.

6. Describe repair/plugging plans.

Currently there are 9 potential tubes requiring tube plugging in SG E-50A and 4 potential tubes in SG E-50B.

All stress corrosion cracking (SCC) indications will be plugged. Any circumferential SCC indications near the top-of-tubesheet (TTS) will be stabilized and plugged. C* depth is applicable to the HL All wear indications (at support structures) greater than or equal to 40%TW will be plugged.

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H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a

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 will 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 tube sheet (TTS) region is inspected with +Pt up to 3 inches above TTS. 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 As of 10/1/2015 at 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br />, the following are the number of potential loose parts identified with the plus point inspection:

E-50A 192 PLP Calls in 131 Tube Locations E-50B 102 PLP Calls in 76 Tube Locations The majority of the indications is historical and has not changed. Visual inspection with FOSAR has been completed in SGB. Anticipate FOSAR in SGA on 10/2/2015 If the loose parts were removed from the SG SG E-50A It is anticipated that FOSAR will start in SG E-50A on 10/2/2015.

SG E-50B The visual inspection will be performed around the periphery of both the hot leg and cold leg and along both sides of the tube lane approximately 3 tubes deep.

Several locations were identified and visually inspected. There were a few new parts identified from last outage. Most were identified as demister wire/sludge.

One location in SGB CL was determined to be a sludge rock. An attempt to remove it was unsuccessful.

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H H F-XC A N GE F-XC A N GE PD PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a Indications of tube damage associated with the loose parts Currently there is 1 location in SGA that has wear associated with the part. An attempt will be made to remove the parts and retest with a volumetric standard. If unable to remove, the affected tube and surrounding tubes will be removed from service.

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).

Sludge lancing was not performed.

There is an ISI inspection (WO-384812) in E-50A which is being supported by the SG Project. This inspection is not part of the SGMP inspections.

10. Discuss any unexpected or unusual results.

An attempt was made to run one of the analysis systems in auto for the tube sheet region. Based on the manual analysis and IQDA inspections, it appears that the Auto system missed an axial crack at the sludge pile. The crack is ~ 0.8 volts. It is still being sized. The auto systems was adjusted to find this type of flaw but manual analysis of the remaining tubes and those affected by the auto analysis is being performed instead.

Currently there are no other unexpected or unusual results. There are no tubes that have failed the screening criteria requiring in-situ pressure testing

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

Once the remainder of the base - bobbin and top of tube sheet, are complete, the special interest test will be performed.

Anticipate complete ECT on 10/4/2015 Anticipate complete repair on 10/6/2015 Anticipate closeout on 10/7/2015 Nozzle dam removal and manway installation on 10/7/2015 6

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a The following is the Primary to Secondary Leak Trend for the Last Fuel Cycle Note: Units in Gallons per Minutes

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a The following is a trend of the Main Condenser Off-Gas Rad-Monitor in GPD

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu ww lic k

to om Table 9-1: Inspection Scope Summary - Wear ww lic k

to om w C .c w C .c tr e tr re ar ac ac k e r- s o ft w k e r- s o ft w a Damage E/P Location Probe / ETSS Scope Expansion / Comments Mech. D/S Bobbin / +Point all new wear, all wear 40%TW, all bobbin Wear Eggcrates E/D/S 100% bobbin except row 1-3 u-bends.

96004.1 I-codes DB/VS

+Point 10908.4 E/D/S 100% +Point row 1-3 u-bends.

+Point all eggcrate wear, and 25% of DB/VS wear not If SCC is coincident with significant DB/VS wear, then P(SCC)/ +Point /

previously inspected, in order to detect any SCC coincident +Point all DB/VS wear in the affected SG. In-situ testing D (see SCC sections) with wear. will be required per CDME-07-119 Bobbin / 100% bobbin except row 1-3 u-bends. Identifies coincident +Point all bobbin I-codes and all bobbin indications Dented VS/DB ( E/D 96004.1 wear and denting (see [3.e]) of coincident wear and denting 5Vpp)

+Point 10908.4 100% +Point row 1-3 u-bends, plus all bobbin indications of E/D/S coincident wear and denting. (see CDME-07-119)

Apply this technique to all VS/DB dents >5Vpp reported by Dented VS/DB (> +Point 10908.4 If wear cannot be sized (depth or voltage), then in-situ E/D/S bobbin probe to ensure detection and sizing 5Vpp) testing will be required of wear (see CDME-07-119)

Bobbin /

Tube to Tube E/D/S 100% bobbin except row 1-3 u-bends. +Point all new wear, +Point all bobbin I-Codes 13091.1 Contact Wear

+Point row 1-3 u-bends.

+Point 13901.1 E/D/S +Point highest eggcrate through the square bend for the tubes surrounding R99 C140 in SGB Bobbin / +Point all bounding tubes with loose part wear or loose Loose Part Wear E/D 100% bobbin and FOSAR both SGs.

27091.2 part indication or visually detected loose part

+Point 27901-27901 thru 27907 when loose part not present (CMOA)

E/D/S 27907 10908.4 when loose part present (CM) 10908.4

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu to to ww om ww om k k w C tr lic

.c Table 9-2: Inspection Scope Summary - Axial ODSCC/PWSCC w C tr lic

.c re re ac ac k e r- s o ft w a k e r- s o ft w a Damage E/P Location Probe / ETSS Scope Expansion / Comments Mech. D/S Bobbin /

Axial E/D 100% bobbin except row 1-3 u-bends. +Point all bobbin I-Codes Non-dented and I28413 ODSCC 2Vpp Dented

+Point /

Eggcrates DB/VS E/D +Point inspection of all bobbin I-Codes for ODSCC detection I28425 Freespan

+Point /

E/S +Point depth and length sizing of detected ODSCC I28432

+Point Row 1-

+Point /

3 U-bends P/D/S 100% +Point row 1-3 u-bends. +Point sizing of any low row indications.

10411.1 Bobbin /

Freespan Ding E/D 100% bobbin except row 1-3 u-bends. +Point all bobbin I-Codes 24013.1 5Vpp

+Point / +Point inspection of bobbin I-Codes at dinged freespan locations for E/D/S 22401.1 ODSCC detection, and length sizing of detected ODSCC.

Freespan Ding

>5Vpp E/D/S +Point / +Point inspection to detect and length size axial ODSCC at 22401.1 dinged and dented locations.

Dented >2Vpp Eggcrates DB/VS

+Point / +Point 100% H/L TTS +3 to 13.5 below the bottom of the expansion +Point 100% of region in affected SG; ensure 20%

Sludge Pile and E/D I28424 transition; +Point inspection of cold leg bobbin I-Codes inspected in the other SG Exp Transition

+Point / +Point inspection for depth and length sizing of detected Axial E/S I28431 ODSCC indications at the sludge pile and expansion transitions.

+Point / (MR)

Axial E/D/S 100% +Point Row 1-3 u-bends Row 1-3 U- 96511.2 If SCC is detected in row 3, then inspect all u-bends in row 4 PWSCC bends of the affected SG, and 20% of row 4 in the unaffected SG.

+Point / (HF)

E/D/S 99997.2 Dented Eggcrates P/D/S +Point / +Point all >2Vpp dents at structures and dings >5Vpp in If an indication is detected, then a scope expansion will be DB/VS 96703.1 freespan; +Point inspection of bobbin I-Codes determined based on the dent voltage and significance of the indication.

Dinged Freespan Tubesheet and +Point 100% H/L TTS +3 to 13.5 below the bottom of the

+Point / +Point 100% of region in affected SG; ensure 20%

Exp Transition E/D/S expansion transition; +Point 20511.1 inspected in the other SG inspection of cold leg bobbin I-Codes

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu to to ww om ww om k k lic lic w .

C tr ac k e r- s o ft w a

.c re Table 9-3: Inspection Scope Summary - Circumferential ODSCC/PWSCC w .

C tr ac k e r- s o ft w a

.c re Damage E/P Location Probe / ETSS Scope Expansion / Comments Mech. D/S Row 1-3 U- +Point / 22842.1 & If SCC is detected in row 3, then inspect all u-bends in row 4 P/D/S 100% +Point row 1-3 u-bends Circ ODSCC bends 21410.1 of the affected SG, and 20% of row 4 in the unaffected SG Dented Eggcrates P/D/S +Point / 22842.1 &

+Point all >2Vpp dents at structures and dings >5Vpp If an indication is detected, then a scope expansion will be DB/VS 21410.1 in freespan; +Point inspection of bobbin I-Codes; determined based on the dent voltage and significance of the circumferential indication Dinged Freespan TTS and +Point 100% H/L TTS +3 to 13.5 below the bottom of the

+Point /

Expansion E/D/S expansion transition; +Point inspection of cold 21410.1 +Point 100% of region in affected SG; ensure 20%

Transition leg bobbin I-Codes inspected in the other SG Expansion +Point / EPRI TR-E/S Sizing of circumferential indications per EPRI TR-107197-P1 Transition 107197-P1

+Point (MR) /

Circ P/D 100% +Point row 1-3 u-bends Row 1-3 U- 96511.2 If SCC is detected in row 3, then inspect all u-bends in row 4 PWSCC bends of the affected SG, and 20% of row 4 in the unaffected SG

+Point (HF) /

P/D 99997.2 Dented +Point / +Point all >2Vpp dents at structures and dings >5Vpp in P/D If an indication is detected, then a scope expansion will be Eggcrates I11524 freespan; +Point inspection of bobbin I-Codes determined based on the dent voltage and significance of DB/VS. Dinged +Point /

P/S Sizing of circumferential PWSCC the circumferential indication Freespan 96701.1

+Point /

P/D 100% +Point row 1-3 u-bends Row 1-3 U- I11524 If SCC is detected in row 3, then inspect all u-bends in row 4 bends +Point / of the affected SG, and 20% of row 4 in the unaffected SG P/S Sizing of u-bend circumferential PWSCC 20510.1

+Point /

E/D +Point 100% H/L TTS +3 to 13.5 below the bottom of the TTS and Exp I11524 +Point 100% of region in affected SG; ensure 20%

expansion transition; +Point inspection of cold leg Transition +Point / inspected in the other SG E/D/S bobbin I-Codes 96701.1

H H F-XC A N GE F-XC A N GE PD Steam Generator Degradation Assessment for Palisades 1R24 Inspection, Fall 2015 PD OW OW N N y y bu bu to to ww om ww om k k lic lic w C .c w C .c tr re tr re ac ac k e r- s o ft w a k e r- s o ft w a Table 9-4: Inspection Scope Summary - Pitting Damage E/P Location Probe / ETSS Scope Expansion / Comments Mech. D/S Bobbin /

Pitting Sludge Pile P/D 100% bobbin exam of the region +Point all bobbin I-Codes 96005.2

+Point /

P/S +Point sizing of detected pitting 21998.1