NL-07-083, Steam Generator Tube Inspection Report for Spring 2007 Refueling Outage

Steam Generator Tube Inspection Report for Spring 2007 Refueling Outage

ML072120612
Person / Time
Site:	Indian Point
Issue date:	07/19/2007
From:	Jones T Entergy Nuclear Northeast, Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-07-083, FOIA/PA-2016-0148
Download: ML072120612 (10)

Text

Entergy Nuclear Northeast Indian Point Energy Center

'" Entergy 450 Broadway, GSB P.O. Box 249 Buchanan. NY 10511-0249 T. R. Jones Licensing Manager Tel 914 734 6670 July 19, 2007 Re: Indian Point Unit 3 Docket No. 50-286 NL-07-083 Document Control Desk U. S. Nuclear Regulatory Commission Mail Stop O-Pl-17 Washington, DC 20555-0001

Subject:

Steam Generator Tube Inspection Report for Spring 2007 Refueling Outage

Reference:

1. NRC letter to Entergy dated August 18, 2004 regarding Evaluation of Steam Generator Tube Inspection Results for 2003. [ML042300253]

Dear Sir or Madam:

Entergy Nuclear Operations, Inc (Entergy) is providing in Attachment I the Steam Generator Tube Inspection Report required by Indian Point 3 Technical Specification 5.6.8. The subject inspection was performed from March 1 5 th through March 1 9 th, 2007 during the Spring 2007 Refueling Outage (3R14).

The scope of the inspection included all four steam generators, which are Westinghouse Model 44F with thermally treated Alloy 690 tubes. At the time of the inspection, the steam generators had approximately 137 effective full power months of operation since the first inservice inspection performed in 1990. All four steam generators were found to be in compliance with condition monitoring requirements. The previous inspection (Reference 1) was performed during the Spring 2003 Refueling Outage (3R12).

There are no new commitments identified in this submittal. If you have and questions or require additional information, please contact me at 914-734-6670.

Licensing Manager Indian Point Energy Center cc: next page AYo (

NL-07-083 Docket 50-286 Page 2 of 2 cc:

Mr. John P. Boska, Senior Project Manager, NRC NRR DORL Mr. Samuel J. Collins, Regional Administrator, NRC Region I NRC Resident Inspector's Office, Indian Point 3 Mr. Paul Eddy, NYS Department of Public Service

ATTACHMENT I TO NL-07-083 STEAM GENERATOR TUBE INSPECTION REPORT FOR INDIAN POINT 3 SPRING 2007 REFUELING OUTAGE (3R14)

ENTERGY NUCLEAR OPERATIONS, INC INDIAN POINT NUCLEAR GENERATING UNIT 3 DOCKET 50-286

NL-07-083 Attachment I Docket 50-286 Page 1 of 7 Steam Generator Tube Inspection Report for Indian Point 3 Spring 2007 Refueling Outage (3R14) 1.0 Examination Program Description At the time of the Spring 2007 refueling outage (3R14) at Indian Point 3, the steam generators (SGs) had accumulated approximateiy 137 effective full power months (EFPM) of operation since the first in-service inspection performed in 1990. The steam generators were replaced in 1989 and each have 3214 tubes made from thermally treated Alloy 690. The reactor coolant system operates with a hot leg temperature of 599 0 F. Refueling outage 3R14 was the refueling outage nearest the endpoint of the first inspection period of 144 EFPM as defined in section 5.5.8.d.2 of the Technical Specifications. The steam generator inspections were performed from March 1 5th through 1 9 th 2007.

The following information is provided as required in section 5.6.8 of the Technical Specifications.

a. The scope of inspections performed on each SG,

b. Active degradation mechanisms found,

c. Nondestructive examination techniques utilized for each degradation mechanism,

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications,

e. Number of tubes plugged during the inspection outage for each active degradation mechanism,

f. Total number and percentage of tubes plugged to date,

g. The results of condition monitoring, including the results of tube pulls and in-situ testing, and

h. The effective plugging percentage for all plugging in each SG.

The tubesheet map and location landmarks are provided in Figure One and Figure Two, respectively.

2.0 Scope of Inspections Performed on each SG The following SG inspection scope was performed on all 4 SGs except as noted:

2.1 Bobbin inspection over the full length of 50% of the tubes in rows 3-45 (about 1515 tubes/SG) in a patterned inspection of every other pair of columns.

2.1.1 In addition, those tubes not inspected since the first ISI in 1990 and not captured in this pattern were added to the inspection plan. This added 324 and 117 tubes in 33 and 34 SGs respectively.

2.2 Bobbin inspection of the hot and cold straight leg sections of 50% of the tubes in rows 1 and 2 aligning with the same columns as the patterned inspection for full length bobbin (about 92 tubes/SG).

2.2.1 In addition, those tubes in row one on both hot and cold legs not inspected in 2003 and not captured in this pattern were added to the inspection plan.

NL-07-083 Attachment I Docket 50-286 Page 2 of 7 2.3 Plus-point inspection of the U-bend sections of those row 1 and 2 tubes inspected in 2.2 above but not 2.2.1 (about 92 tubes/SG) plus any row 3 tubes that could not pass a nominal size bobbin probe. Plus-point probes were used in rows 1 and 2 because the tight radius of the bend does not permit quality data to be collected with the bobbin probe.

2.3.1 In addition, those tubes whose row 1 and 2 U-bend sections were not inspected since the first ISI in 1990 were added to the inspection plan.

This added 19 and 21 tubes to 31 and 32 SG respectively.

2.4 Plus-point inspection of the HOT leg expansion transitions from TTS+3 to TTS-3 inches of 20% of the tubes in a patterned inspection (about 643 tubes/SG) that captured tubes not previously inspected in prior patterns to the extent practical.

The purpose of this inspection was to collect baseline information of the tube expansion transition region for comparison should this region be considered for potential degradation mechanisms.

2.5 Plus-point inspection of the HOT leg expansion transitions from TTS+3 to TTS-3 inches of all HOT leg peripheral tubes (defined as 3 tubes in from the annulus in column, row and diagonal directions and all row 1 and 2 tubes) (about 550 tubes/SG not covered by 20% patterned inspection). The purpose for this inspection was to identify possible loose parts and loose part wear in what are considered the most susceptible regions of the SG.

2.6 Plus-point inspection of the COLD leg expansion transitions from TTS+3 to TTS-3 inches of all COLD leg peripheral tubes (defined as 3 tubes in from the annulus in column, row and diagonal directions and all row 1 and 2 tubes) (about 700 tubes/SG). The purpose for this inspection was to identify possible loose parts and loose part wear in what are considered the most susceptible regions of the SG.

2.7 Special interest inspections as necessary to disposition possible degradation signals from the routine inspections including all dents/dings > 5 volts and a 20%

sample of dents/dings 2.00 - 4.99 volts in the HOT leg straight sections.

I Summary of 3R14 SG Inspections (Number of Tests)

Inspection 31 SG 32 SG 33 SG 34 SG Total Bobbin -(rwFull length bobbin (rows 3-45) 4)1518 1517 1841 1634 6510 Bobbin - Hot leg straight 107 107 134 108 456 section (rows 1 & 2)

Bobbin - Cold leg straight 107 107 134 108 456 section (row 1 & 2)

Plus Pt. - U-Bends (rows 1 111 113 91 90 405

& 2)

Plus Pt. - Hot leg TTS 1226 1216 1235 1248 4925 Plus Pt. - Cold leg TTS 699 694 697 696 2786 Plus Pt. - Special interest 45 4 1 28 78

NL-07-083 Attachment I Docket 50-286 Page 3 of 7 3.0 Active Degradation Mechanisms Found The only tube degradation mechanism found during the SG inspection in 3R14 was freespan wear in two tubes. The wear was due to contact with sludge lancing equipment used in 2001 that has not been used since. Although these tubes were inspected in 2003, the indications were not called at that time because they were at or below the threshold for detection based on the data at the time. The degradation was conservatively sized less than the repair limit and the tubes were left in service. Since the wear was the result of contact with maintenance equipment, the existing wear will not change in the future.

4.0 Nondestructive Examination Techniques Utilized NDE Techniques used for Potential Degradation Mechanisms Detection Detection Sizing Sizing Degradation Probe ETSS Probe ETSS Wear at AVB supports, support Bobbin 96004.1 Bobbin 96004.1 plates & FDB Wear at tube support plates and Bobbin 96004.1 +Point 96910.1 flow distribution baffle plate Wear due to loose parts; Bobbin 96001.1 +Point 21998.1 volumetric indications +Point 21998.1 Axial ODSCC in dents/ding +Point 21409.1 +Point (1)

(>5 volts) +PointI21409.1 I1) _+Point NDE Techniques used for Information Purposes Only Detection Detection Sizing Sizing Degradation Probe ETSS Probe ETSS Pitting Bobbin 96005.2 +Point 21998.1 U-bend axial ODSCC +Point 21409.1 +Point (1)

U-bend circumferential ODSCC +Point 21410.1 +Point (2)

Axial ODSCC at expansion +Point 21409.1 +Point (1) transitions Circumferential ODSCC at +Point 21410.1 +Point (2)

-expansion transitions Note (1) The Vp-p method from CEOG Task 1151 Note (2) EPRI TR-1 07197 5.0 Location, Orientation and Measured Sizes of Service Induced Indications SGID Row Col Orien Ind %TW Loc Inch Comment Wear due contact with 31 1 8 Axial VOL 26 TSC 16.34 sludge lance equipment in 2001 Wear due contact with 31 1 27 Axial VOL 29 TSC 16.16 sludge lance equipment in 1_ 1 2001

NL-07-083 Attachment I Docket 50-286 Page 4 of 7 6.0 Number of Tubes Plugged During 3R1 4 for each Active Degradation Mechanism No tubes were plugged for degradation during 3R14, however, two adjacent tubes in 31 SG were administratively plugged due to a metallic object wedged between the two tubes that could not be retrieved despite several attempts. The object was detected during secondary side visual inspections and confirmed with eddy current. The tubes were evaluated for stabilization which was determined unnecessary given the location and extent of circumferential contact. The tube plugging list from 3R14 is below.

Indication Degradation SG Tube Location Depth %TW Reason for Plugging 31 R29 C79 TSH +0.57 <Detectable Irretrievable Object 31 R29 C80 TSH +0.26 <Detectable Irretrievable Object 7.0 Total Number and Percentage of Tubes Plugged to Date SG 31 SG 32 SG 33 SG 34 Total Total Number of Tubes 3214 3214 3214 3214 12856 Number of Plugged Tubes 3 6 3 4 16

% of Tubes Plugged to Date 0.09% 0.19% 0.09% 0.12% 0.12%

8.0 Results of Condition Monitoring The 3R14 refueling outage represented the end of the eighth fuel cycle after steam generator replacement and the end of the first inspection period following the first in-service inspection in 1990. Consequently, all four steam generators were inspected. A Condition Monitoring assessment was performed, on a defect-specific basis, to demonstrate compliance with integrity criteria by the comparison of 3R14 NDE measurements with calculated burst and leakage integrity limits. Calculated integrity limits, including consideration for appropriate uncertainties, burst and leak analytical correlations, material properties, NDE technique, and analyst uncertainties were provided in the degradation assessment report. All indications in this inspection were below the calculated integrity limits and, therefore, met integrity requirements without further testing. Based upon the inspection results, all four steam generators were found to be in compliance with Condition Monitoring requirements.

All measured tube degradation was less than the condition monitoring limit. No in-situ pressure testing was required nor were any tubes pulled for examination.

NL-07-083 Attachment I Docket 50-286 Page 5 of 7 9.0 Effective Plugging Percentage for all Plugging in each SG SG 31 SG 32 SG 33 SG 34 Total Total Number of Tubes 3214 3214 3214 3214 12856 Number of Sleeved Tubes 0 0 0 0 0 Number of Plugged Tubes 3 6 3 4 16 Effective Tube Plugging % 0.09% 0.19% 0.09% 0.12% 0.12%

Note: Since there are no sleeves installed and the safety analyses credit plugged tubes with the same value regardless of location, the effective tube plugging is equivalent to the percentage of tubes plugged.

NL-07-083 Attachment I Docket 50-286 Page 6 of 7 FIGURE ONE Indian Point 3 Steam Generator Tubesheet Map Coll No.

4-10 - 1 --

12* 1 1--X 13- 1 -X 16--"1 18-'

19-

- 23 I30- 1 11 1

-325- 1X 2-34 1IY 32-' 1 33- x II III I-N53-"

0, 37-'

Z 38---11 6

4083 41c A0 4263 - -

64 65ilt-49*-

675 -

51^^.

NL-07-083 Attachment I Docket 50-286 Page 7 of 7 FIGURE TWO Indian Point 3 Steam Generator Location Landmarks AV3 AV4 AV2 V5 AVI,1 , AV6o 6H 6C 5H 5C 4H 4C 3H 3C 2H 2C 1H -C BPH BPC TSH TSC TEH TEC Westinghouse Model 44F Steam Generator Legend AV = Anti-Vibration Bar (AVB C = cold leg support plate (TSP)

H = hot leg support plate (TSP)

1. = number of support structure BP = baffle plate (FDB)

TS = tubesheet (Hot or Cold)

TE = tube end (Hot or Cold