ML110030005

From kanterella
Jump to navigation Jump to search

October 12, 2010, Turkey Point, Unit 3 - Summary of Conference Call Regarding the Fall 2010 Steam Generator Inspections
ML110030005
Person / Time
Site: Turkey Point NextEra Energy icon.png
Issue date: 01/19/2011
From: Jason Paige
Plant Licensing Branch II
To: Nazar M
Florida Power & Light Co
Paige, Jason C, NRR/DORL,301-415-5888
References
TAC ME4556
Download: ML110030005 (9)
v • d • e


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 19, 2011 Mr. Mano Nazar Executive Vice President and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420

SUBJECT:

TURKEY POINT UNIT 3 -

SUMMARY

OF OCTOBER 12, 2010, CONFERENCE CALL REGARDING THE FALL 2010, STEAM GENERATOR INSPECTIONS (TAC NO. ME4556)

Dear Mr. Nazar:

On October 12,2010, the U.S. Nuclear Regulatory Commission staff participated in a conference call with Florida Power and Light (the licensee) regarding the ongoing steam generator (SG) tube inspection activities at Turkey Point Unit 3. In support of the conference call, the licensee provided Enclosure 1, Steam Generator Tube Inspection Discussion Points. is a summary of the October 12, 2010, SG tube inspection conference call.

Should you have any questions you can contact me at 301-415-5888.

/

IJison C. Paige, Project Manager Lplant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-250

Enclosures:

1. Steam Generator Tube Inspection Discussion Points
2. Summary of October 12,2010 Conference Call cc wi encls: Distribution via Listserv

STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS Turkey Point Unit 3 - October 2010 The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator [SG] tube inspections to be conducted during the upcoming fall 2010, Turkey Point Unit 3 refueling outage. This conference call is scheduled to occur towards the end of the planned SG tube inspections, but before the unit completes the inspections and repairs.

1.

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

Reply: There were no indications of primary to secondary leakage for Turkey Point Unit 3 during the previous operating cycle as evidenced by air removal system, and steam generator blowdown radiation monitoring readings and sampling.

2.

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

Reply: No secondary side pressure tests for Turkey Point Unit 3 during the current outage.

3.

Discuss any exceptions taken to the industry guidelines.

Reply: No exceptions or deviations are taken.

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.

Reply: Please see Table 1. Most inspection samples shown in Table 1 are planned for 100% of the population. Therefore, potential expansion of inspections would be limited to the following +PoinfM inspections:

  • If cracking is detected in the hot leg tubesheet inspections, the remainder of the hot leg tubesheet and a minimum 20% sample would be conducted in the cold leg of the affected SG(s)
  • If cracking is detected in the row 1 or 2 u-bends, the remaining Row 1 & 2 u-bends and a minimum 20% sample would be conducted in next higher row u-bends in the affected SG(s)
  • If cracking is detected in the hot leg or u-bend ding/dent inspections, the remaining ding/dents in the affected region and a minimum 20% sample would be conducted for cold leg dings/dents in the affected SG(s)

In addition to the EGT [eddy current testing] examinations, the following examinations were performed during EOG [end-of-cycle] 24.

- 2 Visual examination of aI/ tube plugs Secondary Side Inspection Upper Bundle Flush Sludge Lance Foreign Object Search & Retrieval (FOSAR)

Pre bundle flush 1h support visual Pre bundle flush steam drum and upper u-bend bundle visual

5.

For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide a summary of the number of indications identified to-date for 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).

Reply: No crack-like indications and no new degradation modes were detected. Please see the fol/owing Table for a summary of wear indications.

Turkey Point Unit 3 Steam Generators October 2010 -Indication Summary for Wear Area Examined Degradation Mode Indication Count Max.

Depth Max.

Voltage Max.

Length Tube Integrity Maintained AVBs (u-bend) wear 175 37%

1.56v Bobbin 0.26" Yes Row 1-2 U-bends see above line none none none none Yes Broach Supports wear 16 40%

1.53v 0.43" Yes Flow Baffle wear 4

20%

0.5v 0.28" Yes DinQslDents none none none none none Yes Top of Tubesheet wear 1

8%

0.11v 0.30" Yes Tubesheet H*

Region (to 17.28")

none none none none none Yes Non-expanded Tubes (9 were pluQQed) none none none none none Yes Region Below H*

(for tube sever) none none none none none Yes

- 3

6.

Describe repair/plugging plans.

Reply: Tube plugging planned includes the following:

9 tubes that are not expanded through the depth of the tubesheet 1 tube - Broached TSP wear 40%

1 tube - AVB wear <40% (preventative) 3 tubes - Broached TSP wear with Possible Loose Part (preventative)

7.

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

Reply: None planned or required.

8.

Discuss the following regarding loose parts:

what inspections are performed to detect loose parts Reply: Secondary side visual inspections of the tubesheet no tube lane and periphery region, and selected inner bundle visuals to investigate known foreign objects and possible loose part (PLP) indications based on ECT analysis.

Reply: Center flow slot regions of tube supports in SG 3B.

a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known)

Reply: Please see Table 2 if the loose parts were removed from the SG Reply: Please see Table 2 indications oftube damage associated with the loose parts Reply: Two broached TSP indication measuring <20% were plugged due to the presence of a small foreign object coincident with the wear indication.

A wear indication measuring 8% and located about 3" above the tubesheet remains in service. A foreign object is suspected of causing the indication, but has never been present since the indication was initially detected approximately 10 years ago.

9.

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

-4 Reply: The secondary side maintenance activities during the current Turkey Point Unit 3 refueling outage include:

a. An inspection of the secondary side u-bend region and center flow slot regions of tube supports in SG B. Findings include only a light coating of deposits. Deposit loading is considered light compared to similar vintage and design units and all flow holes in the supports remain open.
b. Upper bundle flushing of SG A, B, and C.
c. Sludge lancing of flow distribution baffle and top of tubesheet in SG A, B, and C.
d. Top of tubesheet inspections and foreign object retrieval.
10. Discuss any unexpected or unusual results.

Reply: None

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

Reply: Steam generator ECT and tube plugging should be complete on 10/12/10.

Secondary side maintenance and inspections should be completed by 10/15/10.

- 5 TABLE 1 - Basis for Tube Examination Samples Technique Examination Sample 100% f>JII leng'th in rows 3 300 higher. Row 1 & 2 examinations v,i,l be limited to the hot leg BI'rd cold leg straight sections, Bobbin Screenmg of 100% of dings ~ 5 volts In straight sectioos (verticals).

This includes tubes wi'th low-voltage u-bend offset (LVU) tubes per AREVA Fm.."S,1' 50% of the hot leg tuoesheet to the extent of TIS +300 to -17.28 inches. This iflcludes minimum 50% sample of SLG & OXP indications wilhin the TS, The hoi leg full dep'th tubesheet examination includes one unexpanded lube in SG 3A, two unexpanded tubes in SG 36. and li....e unexpanded tube-.s in SG 3C identified 1Mtil previous NTE indications (No Tube Expansion) that will require a fWil tubesheet inspection from TEH to TSH +3.00 Inches. Note: Unexpanded tubes require plugging, based on LAR 241 I~j to f1mtt tubesheet iflscection to a deo1l1 of17.28" All Het Leg and Cold l.eg Penpflery ~l(pa:nsiOil Transmoos - +3"/-2" from top of tubesheet.

'Periphery Tubes' are defined as the two ooter-most peripheral tubes exposed to the annulus, and all open row 1 and 2 tubes in columns 1-92.

Cold Leg full depth tubesheet:

One une~panded tube in SG 36 identified v.~th prevIous NTE indocatioos (No Tube ExpanSi:On) \\'Jilt reqUire B full tubesheet inspectiOO Crom TEe to TSC +300 Inches.

Note: Unexpanded tubes require plugging, based on LAR 241 (;, to ICn1it tubesheet insoocllOn to a deD1h of 17.28'

+Poinf,\\,1 Tight radmus u-bends

-50% of row 1 BOO 2 (not insDected in Drior in$Dection) 50% of hot leg freespan dings>> 5 volts between TSH 1300 06H +1.00" (not inspected in prior inspection) 50% of u-bend dings (not Inspecled in prior inspection) 50% of hot leg dents/dings at structures (not Ins.pected in prior I1spect.on)

Potential Basis Required or Supplementa.1 De~radation IlJVearl Required Degradation Assessl"nent ODSCC Required Degradation.A.ssessment ODSCe Required ENG CSI*2.2, Rev.

32, Foreign Object Checklist item 1.0, and the

'vVear Degradation Assessment.

PVl'SCC Required ODSee Forelgn Object ENG CSI-2.2, Re.'.

32.

Checklist item l.D., and 'the

'Near R.equired Degrada.tion Assessment.

R.equired ENG CSI-2.2, Rev.

3?-,

PWSCC Checklist item1.D., and 'the ODSCC Degradation Assessment.

PNSCe R.equired Degradation Assessment ODSCC P'WSCC Degradation Assessment Required ODSeC P'NSee Degradation,Assessment.

Required ODSeC p'vvsce Required Degradation Assessment.

ODSCC NOTE: Existing degradation mechanisms are wear at anti-vibration bars, tube supports and the flow baffle.

- 6 TABLE 2 - Turkey Point Unit 3 SG Secondary Side Foreign Objects SG Description Removed yes/no Wear Due to Object yes/no SGA Cylindrical object embedded in sludge at TSH No No SGA Object embedded in sludge at TSH No No SGA Magnetic object at TSH Yes No SGB*

Flake-shaped object at TSC No No SGB*

Sludqe Rock at TSH No No SGB*

Hard sludqe at TSH No No SGB*

Rock-like obiect at TSH No No SGB*

Possible slag at TSH No No SGC Hard deposit-like object at TSH No No SGC Tube Scale at TSH No No SGC Cylindrical object at TSH Yes No SGC Sludqe rock at TSC No No SGC Piece of wire at TSH Yes No SGC Piece of wire at TSC Yes No SGC Hard sludqe adhered to hot leq tubesheet No No Objects remaining in the SG are evaluated for unit operation

  • All objects listed for SGB are based on EOC22 (2007) objects that were not removed. Secondary side visual inspection in SGB is scheduled for October 13th.

SUMMARY

OF CONFERENCE CALL WITH TURKEY POINT UNIT 3 REGARDING THE FALL 2010 STEAM GENERATOR TUBE INSPECTION RESULTS DOCKET NUMBER 50-250 On October 12, 2010, the U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with Florida Power and Light (the licensee) regarding the ongoing steam generator (SG) tube inspection activities at Turkey Point Unit 3.

Turkey Point Unit 3 has three Westinghouse Model 44F SGs. The SGs have tubes that were hydraulically expanded into the tubesheet. The tubes are supported by Type 405 stainless steel tube support plates with broached quatrefoil holes. The Unit 3 steam generators were placed into operation in 1982, and have thermally treated Alloy 600 tubing.

Additional clarifying information or information not included in the document provided by the licensee is summarized below:

  • The licensee performed sludge lancing and reported that the sludge lance pressure was 3,000 pounds per square inch.
  • The licensee reported that three tubes, with wear and a possible loose part indication at a broached tube support plate, were plugged since no qualified sizing technique exists for this degradation mechanism.

The NRC staff did not identify any issues that required follow-up action at this time, however, the staff asked to be notified in the event that any unusual conditions were detected during the remainder of the outage.

January 19, 2011 Mr. Mano Nazar Executive Vice President and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420

SUBJECT:

TURKEY POINT UNIT 3 -

SUMMARY

OF OCTOBER 12, 2010, CONFERENCE CALL REGARDING THE FALL 2010, STEAM GENERATOR INSPECTIONS (TAC NO. ME4556)

Dear Mr. Nazar:

On October 12,2010, the U.S. Nuclear Regulatory Commission staff participated in a conference call with Florida Power and Light (the licensee) regarding the ongoing steam generator (SG) tUbe inspection activities at Turkey Point Unit 3. In support of the conference call, the licensee provided Enclosure 1, Steam Generator Tube Inspection Discussion Points. is a summary of the October 12, 2010, SG tube inspection conference call.

Should you have any questions you can contact me at 301-415-5888.

Sincerely, IRA!

Jason C. Paige, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-250

Enclosures:

3. Steam Generator Tube Inspection Discussion Points
4. Summary of October 12, 2010 Conference Call cc w/ encls: Distribution via Listserv Distribution:

PUBLIC LPL2-2 rtf RidsNrrDrlLpl2-2 RidsNrrPMTurkeyPoint RidsNrrDciCsgb RidsRgn2MailCenter KKarwoski, NRR AObodoako, NRR RidsNrrLABClayton ADAMS Accesslon No. ML110030005

  • BIV memo OFFICE LPL2-2/PM LPL2-2/LA CSGB/BC LPL2-2/BC NAME

~IPaige BClayton RTaylor*

DBroaddus (TOrt for)

DATE 1/03/11 1/03/11 11/08/10 1/19/11 OFFICIAL RECORD COpy

Retrieved from "https://kanterella.com/w/index.php?title=ML110030005&oldid=5287046"