ML100251277
| ML100251277 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 01/27/2010 |
| From: | Jason Paige Plant Licensing Branch II |
| To: | Florida Power & Light Co |
| Paige, Jason C, NRR/DORL,301-415-5888 | |
| References | |
| TAC ME2536 | |
| Download: ML100251277 (9) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 27, 2010 LICENSEE: Florida Power & Light FACILITY: Turkey Point Unit 4 SUB..IECT:
SUMMARY
OF NOVEMBER 10, 2009, CONFERENCE CALL WITH FLORIDA POWER & LIGHT, ON THE FALL 2009 STEAM GENERATOR INSPECTIONS (TAC NO. ME2536)
On November 10, 2009, a conference call was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Florida Power & Light (the licensee) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss the ongoing steam generator (SG) inspection activities at Turkey Point Unit 4.
Turkey Point Unit 4 has three Westinghouse Model 44F replacement SGs. Each SG has 3214 thermally treated Alloy 600 tUbes. The tubes have a nominal outside diameter of 0.875 inch, and a nominal wall thickness of 0.050 inch. The tubes are supported by stainless steel tube support plates with quatrefoil-shaped holes and V-shaped antivibration bars. The tubes were hydraulically expanded through the full depth of the tubesheet.
Prior to the conference call, the licensee provided a written response to a set of discussion points from the NRC staff (Agencywide Documents Access and Management System Accession No. ML090550826). Names of the participants are shown in Enclosure 1. The licensee's response is included as replies to discussion points in Enclosure 2.
Abbreviations used by the licensee in Enclosure 2 include:
- AVB - Anti-vibration bars
- BET - Bottom of expansion transition * +Point - Plus Point'
- DSI - Distorted support indication
- PWSCC - Primary water stress
- ECT - Eddy current testing corrosion cracking
- EOC - End of cycle
- RxCx - Row x Column x
- F.O. - Foreign Object
- TBD - To be determined
- FSOR - Foreign Object Search &
- TP4-xx - Turkey Point Unit 4, Refueling Retrieval outage number xx
- H* - H star
- TSH - Top of tubesheet, hot-leg side
- HL or H/L - Hot leg
- TIS - Top of tubesheet
- ODSCC - Outside diameter stress
- V - Volts corrosion cracking
-2 Additional clarifying information and information not included in the enclosed document is summarized below.
The results of the BET examination showed that the lowest BET left in service was approximately 0.5 inch below the TIS.
The ding in the tube that is being preventively plugged for wear coincident with the ding has a bobbin coil voltage of approximately 3 V.
The FOSAR examination of SG A was ongoing at the time of the conference call.
The object in SG C is a new object. This region of the tube bundle has a low-flow velocity.
Approximately 15 to 30 pounds of sludge per SG is removed during the sludge lancing operation.
Based on the information provided, the NRC staff did not identify any issues that warranted immediate foliowup action.
Please direct any inquiries to me at 301-415-5888 or Jason.Paige@nrc.gov.
- ncerely, 1-Jason C. Paige, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-251
Enclosures:
- 1. Steam Generator Tube Inspection Discussion Points
- 2. List of Attendees cc w/encls: Distribution via Listserv
LIST OF PARTICIPANTS NOVEMBER 10, 2009, NUCLEAR REGULATORY COMMISSION (NRC)
CONFERENCE CALL WITH FLORIDA POWER & LIGHT (FPL)
TURKEY POINT UNIT 4 FALL 2009 STEAM GENERATOR INSPECTIONS Name Organization Jason Paige NRR Ken Karwoski NRR Andrew Johnson NRR Bob Tomonto FPL Olga Hanek FPL Gary Boyers FPL ENCLOSURE 1
STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS Turkey Point Unit 4 - November 2009 The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator tube inspections to be conducted during the upcoming fall 2009, [Turkey Point] Unit 4 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.
The NRC staff plans to document a summary of the conference call as well as any material that is provided in support of the call.
- 1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.
There were no indications of primary to secondary leakage for Turkey Point Unit 4 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.
There are no planned secondary side pressure tests for Turkey Point Unit 4 during the current outage.
- 3. Discuss any exceptions taken to the industry guidelines.
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.
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 fol/owing +Point' inspections:
- If cracking is detected in the hot leg tubesheet inspections, a minimum 20%
sample would be conducted in the cold leg of the affected SG(s)
- If cracking is detected in the row 2 U-bend, a minimum 20% sample would be conducted in row 3 U-bends in the affected SG(s)
- If cracking is detected in the ding/dent inspections, a minimum 20% sample would be conducted for cold leg dings/dents in the affected SG(s)
In addition to the EGT examinations, the fol/owing examinations will be performed during EOG 24.
Visual examination of aI/ tube plugs Secondary Side Inspection ENCLOSURE 2
-2
- Upper Bundle Flush
- Sludge Lance
- Foreign Object Search & Retrieval (FOSAR)
- 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).
Turkey Point Unit 4 Steam Generators November 2009 Indication Summary Area Examined Degradation Indication Max. Max. Max. Tube Integrity Mode Count Depth Voltaqe Lenqth Maintained AVBs (u-bend) wear 50 22% 0.77v <0.6" Yes Row 1-2 U-bends none -- -- - - --
Broach Supports wear 4* 16% 0.27 0.59" Yes Flow Baffle wear 4 12% 0.41v TBD Yes Dings/Dents none -- -- -- -- -
Top of Tubesheet none -- -- -- -- --
Tubesheet H* none - -- - -- --
Region (to 17.28")
Non-expanded none -- - - - -
Tubes Region Below H* none -- -- - - --
(for tube sever)
- 8 DSI pending +Point' testing
- 6. Describe repair/plugging plans.
Tube plugging planned includes the following:
- 9 tubes that are not expanded through the depth of the tubesheet
- 1 tube (preventative) - BET is 1.07" below the top of the tubesheet
- 1 tube (preventative) - AVB wear coincident with ding (sizing not qualified)
-3
- 7. Describe in situ pressure test and tube pull plans and results (as applicable and if available).
None planned or required.
- 8. Discuss the following regarding loose parts:
- what inspections are performed to detect loose parts 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.
Center flow slot regions of tube supports 3-6 in SG 4C.
- a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known)
Please see Table 2
- if the loose parts were removed from the SG Please see Table 2
- indications of tube damage associated with the loose parts There is no tube damage is associated with any loose part
- 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).
The secondary side maintenance activities during the current Turkey Point Unit 4 refueling outage include:
- a. An inspection of the secondary side u-bend region and center flow slot regions of tube supports 3-6 in SG C. Findings include only a light coating of deposits.
Deposit loading is considered light compared to similar vintage and design units.
- 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 (17 Lbs).
- d. Top of tubesheet inspections and foreign object retrieval.
- 10. Discuss any unexpected or unusual results.
None
- 11. Provide the schedule for steam generator related activities during the remainder of the current outage.
Steam generator ECT and tube plugging should be complete on 11/11/09.
Secondary side maintenance and inspections should be completed by 11/13/09.
- 4 TABLE 1 - Basis for Tube Examination Samples Required or Potential Technique Examination Sample Basis Supplemental Degradation 100% full length in rows 3 and higher. Row 1 & 2 examinations will be limited to Required Degradation Wear/
the hot leg and cold leg straight sections. Assessment ODSCC Bobbin Degradation Screening of 100% of dings ~ 5 volts in straight sections (verticals). Required ODSCC Assessment 100% of the hot leg tubesheet to the extent of TTS +3.00 to -17.28". Required F.O. Wear Degradation PWSCC Hot leg full depth tubesheet examination: Two unexpanded tubes in SG "A" and Assessment.
Required ODSCC five unexpanded tUbes in SG "B" identified with NTE indications (No Tube Expansion).
Cold Leg Periphery Expansion Transitions - +3"/-2" from top of tubesheet. Required Area of F.O.
Two outermost peripheral tubes exposed to the annulus, and all open row 1 and 2 higher Wear tubes in columns 1-92 to complete the periphery examination. potential for wear Cold Leg full depth tubesheet examination: One unexpanded tube in SG "A" and Degradation PWSCC
+Point' one unexpanded tube in SG "B" identified with NTE indications (No Tube Required Assessment ODSCC Expansion ).
Tight radius u-bends - 100% of row 1 and 2 Required Degradation PWSCC Assessment ODSCC 100% of hot leg frees pan dings> 5 volts between TSH and 06H +1.00". Required Degradation PWSCC Assessment ODSCC 100% of u-bend dings Required Degradation PWSCC Assessment ODSCC 100% of hot leg dents/dings at structures. Required Degradation PWSCC Assessment ODSCC NOTE: Existing degradation mechanisms are wear at anti-vibration bars, tube supports and the flow baffle.
-5 TABLE 2* Turkey Point Unit 4 SG Secondary Side Foreign Objects (Actively Tracked) as of 11*9*09 Item S/G Description TP4-23 Location TP4-24 Location TP4-25 Location Initial Location
& Basis & Basis & Basis 11/09 And Basis (11/2006) (4/20/08)
ECT PLP Object Seen by FOSAR 1/16' x 2" embedded In hard 04/08 no retrieval 1 4A H/L R22/23 C46 TBD Wire sludge retrieval attempted, fixed unsuccessful in location ECT PLP Object Located in hard embedded In hard 1/32" x 1" sludge pile region, TBD 2 4A H/L R 12/13 C 38 sludge on tube wire coil no retrieval retrieval attempted unsuccessful Seen by FOSAR Seen by FOSAR H/L Rl0/ll C76/77 1/16" x 2" 11/06 Retrieva I 04/08, no retrieval 3 4A (SSI Report shows TBD Weld Rod attempts attempted, fixed in C75/76) unsuccessful location
.1" x .15" x PLP (no wear)
ECT verified
.5" presence Visual confirmed 4 4C oblong H/L R 20/21 C 47 ECT Skip Cycle (Based on look 11/09 object metallic wedged tightly.
back) object Retrieval unsuccessfu I.
ML100251277 OFFICE DORULPL2-2/PM DORULPL2-2/LA DORULPL2-2/BC NAME JPaige BClayton TBoyce DATE 01/27/10 01/27/10 01/27/10