3F1297-22, Forwards Special Rept 97-05 IAW Improved TS 5.7.2.c & Complete Results of OTSG Tube Inservice Insp Performed During Current Outage Which Includes Listed Info

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Forwards Special Rept 97-05 IAW Improved TS 5.7.2.c & Complete Results of OTSG Tube Inservice Insp Performed During Current Outage Which Includes Listed Info
ML20202J770
Person / Time
Site: Crystal River Duke Energy icon.png
Issue date: 12/05/1997
From: Rencheck M
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20202J773 List:
References
3F1297-22, NUDOCS 9712110238
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@Florida Power COptPORATION Geo No le 302 December 5,1997 3F1297-22 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

=

Subject:

Special Report 97-05

- Once Through Sten Generator (OTSG) Notifications Reevired Prior to MODE 4, and Complete Results of OTSG Tube Inservice Inspection Performed During the Current Outage (90-Day Report)

Dear Sir:

L' l The purpose of this letter is to submit Special Report 97-05 in accordance with improved Technical Specification (ITS) 5.7.2.c. Accordingly, Florida Power Corporation (FPC) is providing the following notifications required by ITS 5.7.2.c prior to MODE 4:

1. Number of tubes plugged and sleeved,
2. Crack-like indications in the first span,
3. An assessment of growth in the first span intergranular attack (IGA) indications, and
4. Results of in-situ pressure testing, if performed. Note: No in-situ pressure testing was performed.)

Additionr.Ily, FPC is also providing, in accordance with ITS 5.7.2.c, the complete results of the OTSG tube inservice inspection performed during the current outage (90-Day Report) which includes the following information:

U Y,'

1. Number and extent of tubes inspected, \

s

2. Location and percent of wall-thicloess penetration for each indication of an imperfection,
3. Location, bobbin coil amplitude, and axial and circumferential extent (if determined) for each first span IGA indication, and

- 4. Identification of tubes plugged and tubes sleeved. llllllll[lllll]llllllllllllllllllll 971211023G 971205 PDR ADOCK 05000302 PDR RYSTAL RIVEP ENERoY COMPLEX 15760 W. Power L6ne street

  • Crystal River, Florida 34428-6708 + (352) 795-6486 A Horteta Progress Company I _____

= U.S. Nuclear Regulatory Commission -

3F1297-22 Page 2 of 2 Consistent with proposed License Amendment Request No. 221, Revision 0, submitted on October 1,1997~ (FPC letter 3F1097-21), FPC will complete and Submit an operational assessment for first span pit-like IGA within 90 days following plant restart.

If you have any questions regarding this letter, please contact Mr. David Kunsemiller, Manager, Nuclear Licensing (352) 563-4566.

Sincerely

. W. Rencheck

& l-Director, Nuclear Engineering and Projects MWR/LVC .

cc: Regional Administrator, Region ll Senior Resident inspector .

NRR Project Manager Attachments:

A. List of Regulatory Commitments B. Special Report 97-05 Appendix 1, "B" OTSG First Span Growth Assessment

- Appendix 2, Identification of Tubes Plugged and Sleeved l

Appendix 3, "B" OTSG, First Span IGA Bobbin Data Appendix 4, "B" OTSG, First Span MRPC Clip Plot Data Appendix 5, "A" OTSG Plugged Tubes Results Listing

- Appendix 6, "B" OTSG Plugged Tubes Results Listing Appendix 7. "A" OTSG Inservice Tubes with 1% to 39% Indications Appendix 8, "B" OTSG Inservice Tubes with 1% to 39% Indications

I U.S. Nuclear Regulatory Commission Attachment A 3F1297-22 Paga 1 of 1 1

J ATTACHMENT A List of Regulatory Commitments The ',bliowing table identifies those actions committed to by Florida Power Corporation in this document.

Any other actions discussed in the submittal represent intended or planned actions by Florida Power Corporation. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Manager, Nuclear Licensing, of any questions regarding this document or any associated regulatory commitments.

ID Number Commitment Commitment Date 3F1297-22 FPC will submit an operational assessment for 90 days following plant first span pit-like IGA within 90 days following restart.

plant restart.

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ATTACHMENT B  !

SPECIAL REPORT 97-05 l

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U.S. Nuclear R:gul: tory Conunission .[

3P1297 22  !

ITS 5.7.2.c.

- SPECIAL REPORT 97-05 g .t Special reporting requirements of ITS 5.7.2.c. are shown in italics. The CR 3 responses are in  ;

normal font.

Follouing each Insenice inspection of the steam generator (015G) tubes, the NRC shall be notified of thefollouing prior to ascension into MODE 4: .

1. Number of tubes plugged and sleeved. ,

"A" OTSG: 77 Tubes Plugged 0 tubes sleeved  ;

"11" OTSO: 483 Tubes Plugged 0 tubes sleeved c 2. Crack like indications in thefirst span The "Grst span" is defined as those lengths of tubing which span the region from the lower tubesheet secondary face to the first support plate. The number of crack like indications found in this region:

"A" OTSG: 0 i

"B" OTSG: 0

3. An assessment ofgrou1h in thefirst span indications, and i CR-3 evaluated "B" OTSG first span pit like IGA growth using three distinct methods:

i indicated % throughwall as determined by spplying the qualified eddy current depth sizing technique for Grst span IGA,600 kHz high frequency bobbin voltage, and 300 kHz pancake

coil clip plot measurement.

Appendix 1 of this Special Report includes a detailed discussion and graphics depicting the results of these assess nents.

[ '

The Crystal River Unit 3 growth data continues to demonstrate growth distribution curves centered about the zero point.

4. Results ofin-situ pressure testing, ifperformed.

There was no in-situ pressure testing performed during the 1997 OTSG inspection.

The complete results of the 01SG tube insenice inspection shall be submitted to the NRC uithin 90 daysfollouing the completion of th inspection. The report shallinclude:

1. - Number and extent of tubes inspected, ITS 5.7.2.c. Special Report 97-05 Page 1 of 9 4

Summer 1997 Inspections

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- U.S. Nuclect Regulatory Commission 3F1297-22 --

JLQDBIN EXAMS:

"A" OTSG: 15,457 Tubes Examined -(100% ofinservice tubes)

  • B" OTSG: 15.380 Tubes Examined (100% ofinservice tubes)

All tubes in both OTSGs had at least one bobbin exam. The bobbin exams were primarily performed from the lower bowls of the generators. There were a limited number of bobbin exams from the upper bowls. The upper bowl exams were performed to obtain bobbin data in the lower bowl robotic manipulator (Roger) exclusion zones (the tubes that the lower bowl Roger manipulator would not be able to test due to the base of the manipulator sitting over the tubes). CR-3 attempted to test each tube full length, however, due to tube end damage in both OTSGs, some tubes were only capable of being tested to within a few inches of the tube end.

The extents tested were:

"/ : 'TSG:

Lud Tested Number of Tubes Percent of All Tubes Tested in Smitt 2-LTE - UTE (Lower Tube End to Upper Tube End, i.e., full length) 7,219 47 %

, LTE - UTR (Lower Tube End to Upper Roll Transition) 768 5%

LTE - UTS (Lower Tube End to a point in the Upper Tubesheet Region 8'075 52 %

near, but not capturing, the UTR)

TOTALS *: 16,062 104 %

1here were 15,457 tubes in service in *A

  • OTSG prior to 1997 inspections.

"B" OTSG:

Extent Tested Nurnber of i)thes Percent of All

. Tested Tubes in Service LTE - UTE (Lower Tube End to Upper Tube End, i.e., full length) 13,277 86 %

LTE - UTR (Lower Tube End to Upper Roll Transition) 196 1%

LTE - UTS (Lower Tube End to a point in the Upper Tubesheet Ragion 1*940 13 %

near, but not capturing, the UTR)

TOTALS *: 15,413 100 %

1here were 15,380 tubes in service in ~B

  • OTSG prior to 1997 inspections.
  • Totals will exceed 100% due to some tubes being tested more than once.

ITS 5.7.2.c. Special Report 974)5 Page 2 of 9 Summer 1997 Inspections

U.S. Nuclear Regul: tory Commission

. 3F1297 22 The general bobbin exam was performed with the ZETEC A-510-M/ULC bobbin probe,100 foot length, ZETEC Part Number 760-1192.

Indications !dentified with the bobbin coil examination were identified as a non-quantifiable.

Indication (NQl) unless the indication was attributed to wear. NQls identified in 1997 were further dispositioned by the use of a motorized rotating coil probe (MRPC). The probe used.

for these examinations was the ZETEC 520 Plus Point Delta Probe, ZETEC D#3610-7-A.

-This probe head was equipped with a Plus Point coil, a 0.115" diameter pancake coil, and a 0.080" diameter (mid frequency range) pancake coil. Results summary:

"A" OTSG MECHANISM # OF IND. # OF TUBES WEAR 1% to 39% (BOBBIN) 234 219

-WEAR 1% to 39% (MRPC) 109 101

. WEAR 240% (MRPC) 0 0 .

MANUFACTURING BURNISH MARK (MBM) 156 122 l FREESPAN AXIAL INDICATIONS 1 i FREESPAN SINGLE VOLUMETRIC IND. (SVI) 9* i SVI / MCI (MULTIPLE CIRCUMFERENTIAL 16** l's l INDICATIONS) / SCI (SINGLE CIRC. IND.) AT SECONDARY FACE OF UPPER TUBESHEET

  • Tsv of these indicatioru nere associated with dings which urre ident@ed as NQls during the bobbin exam. The i tuo dings (in tubes A.35.59 arul A 78.103) exhibitedpossible outer diameter wlumetric unit lass. A review of '

historical data derrwnstrated that these hulications had been present in the past, arul bobbin restwnse shourd tw evidence ofchange.

l ** Four of these irulicatwrts ha the lane arul sedge regi<m sere recorded as circumferential (SCIor MCI) due to

}_ the coil restwue. Ilourver, on the c scan plots, thesepur hulicatwns appear similar (pit-like) to the other St7s at

! the sewrularyface of the UTS.

"B" OTSG MECHANISM . # OF IND.  : # OF TURES WEAR 1% to 39% fBOBBIN) 528 '513' WEAR 1% to 39% (MRPC) 338 302 I WEAR 240% (MRPC) 0 0 MANUFACI'URING BURNISH MARK 110 89 FREESPAN AX1AL INDICATIONS 0 0 FREESPAN SVI 2 2 SVI AT SECONDARY FACE OF UPPER 2 2 TUBESHEET These tables do not include indications found in the upper roll transition exams.

About 600 tubes in the "B" OTSG were examined using the ZETEC A-510-M/ULC/HF bobbin probe,100 foot length, ZETEC Part Number 760-1194. These examinations were limited to the "B" OTSG. first span for tubes that had pit-like IGA indications which were -

sized using the regression sizing technique.

Appendixes 5 and 6 contain the inspection results for all tubes plugged in "A" and "B" OTSGs.

ITS 5.7.2.c. Special Report 97-05 Page 3 cf 9 Summer 1997 inspections

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1 U.S. Nuclear Regulatory Commission

- 3Pl297 22 -

ROTATING COIL EXAMS IN UPPER ROLL TRANSITIONS:

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Rotating coil exams were performed at the upper roll transition (hot leg) for each inservice-tube in both _OTSGs. Number of tubes inspected:  ;

"A" OTSG: '15,457 Tubes Examined (100% ofinservice tubes)

"B" OTSG:

15,380 Tubes Examined (100% of inservice tubes)

The scheduled extent of these examinations was from the tube end to two inches below the tube end. This extent of exam was designed to ensure that the entire length of the roll expanded area (about one inch in length) plus about the first half to three quarters of an inch past the roll transition was examined.

The probe used for these exa ainations was the ZETEC 520 Plus Point Delta Probe, ZETEC D#3610-7-A.- This probe head was equipped with a Plus Point coil, a 0.ll5" diameter pancake coil, and a 0.080" diameter (mid frequency range) pancake coil.

Summary of indications found in the roll transition examinations:

"A" OTSG AXIAL # OF TUBES- CIRC.- # OF TUBES VOLUM. # OF TUBES 5 5 0 0 47 46 TOTAL # OF TOTAL INDICATIONS - # OF TUBES 52 51 "B" OTSG AXIAL - # OF TUBES CIRC. # OF TUBES VOLUM. # OF TUBES 49 45 1 1 9 -8 TOTAL # OF - TOTAL INDICATIONS # OF TUBES 59 51 Note that some tubes had multiple similar indications or indications of different types, thus the total number of tubes affected is not determined simply by adding up the indication counts or number of tubes affected for the individual indication types.

CR-3 does not have any qualified sizing techniques for these types of indications. All of the indications identified in these tables were plugged.

Appendixes 5 and 6 contain the inspection results for all tubes plugged in "A" and "B" OTSGs.

1 ITS 5.7.2.c. Special Report 97-05 Page 4 of 9 Summer 1997 Inspections

U.S. Nuclear R:gul:. tory Commission 3F1297 22 ROTATING COIL EXAh1S IN LOWER TUBESHEET CREVICE REGION:

A 3% sample of the total tube population was examined full length in the lower tubesheet crevice region. 928 tubes were examined from the lower tube end to the secondary face of j the lower tubesheet. This examination was performed only in the "B" OTSG.

The probe used for these examinations whs the ZETEC 520 Plus Point Delta Probe, ZETEC D#3610-7 A. This probe head was equipped with a Plus Point coil, a 0.115" diameter pancake coil, and a 0.080" diameter (mid frequency range) pancake coil.

No reportable indications were identified by this inspection.  ;

BOBBIN COIL EXAMS IN SLEEVED TUBES:

Prior to the 1997 inspection, each OTSG had 163 sleeves in service.

A 22% sample of the total sleeve population was examined full length (of the sleeve) with a bobbin probe. 71 sleeved tubes were examined full length of the sleeve. This examination was performed only in the "A" OTSG.

The sleeve bobbin exams were performed with the ZETEC A-400-FM bobbin probe,50 foot length, ZETEC Part Number 751-0202 or the ZETEC bobbin probe D#3937-1 A,100 foot length.

No reportable indications were identified by this inspection.

ROTATING COIL EXAMS IN St.EEVED TUBES:

A 20% sample of the total sleeve population was examined with a rotating Plus Point probe.

66 sleeved tubes were examined in the roll expansion areas. This examination was performed only in the " A" OTSG.

The probe used for tF~e examinations was the ZETEC OTSG - 0.400" Sleeve Gimbaled Plus Point Probe, ZETLC D#3331-2-A.

No reportable indications were identified by this inspection.

ROTATING COIL EXAMS OF DINGS:

A large quantity of dings were inspected with the rotating coil probe in the Summer 1997-inspections. The probe used for these examinations was the ZETEC 520 Pius Point Delta Probe, ZETEC D#3610-7-A. This probe head was equipped with a Plus Point coil, a 0.115" diameter pancake coil, and a 0.080" diame:er (mid frequency range) pancake coil, in 1997, the ding reporting criteria off the bobbin inspection was established at 3 volts on the

! 400/200 kHz differential mix channel, regardless of ding location. [ Recall that the voltage i normalization in 1997 was established as 4 Vn (volts peak-to-peak) on the 4 x 20%

throughwall holes on 400 kHz.]

j ITS 5.7.2.c. Special Report 97-05 Page 5 of 9 Summer 1997 Inspections 1

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U.S. Nu: lear Regubtory Commission 3F1297 22 ;

The distribution of dings recorded in 1997 is summarized below,

REGION - "A" OTSG "B" OTSG - TOTAL Upper Tubesheet 102 6 108 Crevice
Upper Tubesheet 14 6 20-Secondary Face i Freespan 70 35 105 1 3:

Support Plates 4 2 6 Lower Tubesheet 1394 571 1965 i

Secondary Face Lower Tubesheet 65 166 231-

, Crevice

- TOTAIS: 1649 786 2435 The criteria used to select dings for the rotating coil exams were:

E 50% of the dings @ LTS Secondary Face 220V.

10% of the dings @ LTS Secondary Face between 10V and 20V.

3 All dings adjacent to explosive plug locations, in other locations,100% of the dings > 10V.

l This criteria resulted in 441 dings being inspected throughout both generators. A number of additional dings were inspected as a result of scheduled rotating coil exams for first span IGA, i lower tubesheet crevice exams, and other special interest RPC exams, but those ding exams were not counted toward these totals, L No reportable indications were identified by these ding inspections.

i.

ROTATING COIL EXAMS IN ROLLED PLUGS:

4, 100% of the inconel 600 rolled plugs were inspected with a rotating pancake coil probe. The number of plugs inspected:

i OTSG UPPER HEAD LOWER HEAD A 10 10 j- B 24 23 TOTAL: 34 33 i

20% of the upper head inconel 690 rolled plugs were inspected with a rotating pancake coil

. probe. - The distribution of these plugs is:

OTSG UPPER HEAD A 14 B 21 3

TOTAL: 35 ITS 5.7.2.c. Special Report 97 05 Page 6 of 9 3- - Summer 1997 Inspections 4

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U.S. Nuclear Rigul: tory Commission 3F1297-22 The probe used for these examinations was the ZETEC 410PG Rolled Plug Inspection Probe, ZETEC D#1430-8-E This probe head was equipped with a 0.115" diameter magnetically biased pancake coil.

No reportable indications were identified by this inspection.

2. hcation and percent unit thickness penetrationfor each indication of an imperfection, The only indications which are given a percent wall penetration are "B" OTSG first span pit-like IGA indications and tube support plate wear indications. Other indications of wall loss or cracking are plugged on detection and are not assigned a percent wall penetration value.

A complete listing of Wection results for plugged tubes in "A" and "B" OTSGs is provided in Appendixes 5 and o.

A complete listing of inspection results for inservice tubes with indications from 1 % to 39%

throughwall in "A" and "B" OTSGs is provided in Appendixes 7 and 8. Note that the only CR 3 degradation mechanisms which receive a percent throughwall value are tube support plate wear and "B" OTSG first span pit-like IGA.

3. Lot 2 tion, bobbin coil amplitude, and axial and circumferential extent (ifdetermined)for each first span IGA indication, All known "B" OTSG tubes with first t. pan pit-like IGA indications are presented in Appendix 3. This table contains the high frequency bobbin coil data for each pit-like IGA indication which was given a percent throughwall. The location, indicated percent throughwall, and the bobbin coil amplitude off the 600 kHz high frequency bobbin coil of each indication is provided. 1996 and 1997 indicated percent throughwall numbers have been adjusted in accordance with the description found in Appendix 1, First Span Growth Assessment, and are shown under the columns labeled "Cor. %TW." Based on the discussions in Appendix 1, the 1994 and 1992 regression algorithm percent throughwall numbers did not need adjustment. These unadjusted values are shown under the " Raw

%TW" column heading. For indications which had historical high frequency bobbin data reanalyzed, the results of those reanalyses are also presented.

Clip plot measurements were established only for first span pit-like indications which had a clip plot measurement recorded in a previous inspection. The clip plot data is provided in Appendix 4.

and ITS 5.7.2.c. Special Report 97-05 Page 7 of 9 Summer 1997 Inspections

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U.S. Nuclear Regulatory Commission 3F1297-22

4. Identifcallon of tubes plugged and tubes sterwd.

A concise listing of tubes which were plugged is presented in Appendix 2. To summarize:

" A" OTSG Number of Tubes Plugged Due to:

Indications in Upper Roll Transitions: 51 Indications at UTS Secondary Face:

  • 15 Volumetric Indications in Freespan: 9 Axial Indications in Freespan: 1 Administratively Plugged due to an Unusual Dent in Lower Tubesheet: 1 TOTAL: 77
  • 0ne tube (A 73,66) accountedfor in the roll traruition count also had an irufication at dne secorularyface.

A complete listing of inspection results for plugged tubes in "A" OTSG is provided in Appendix 5.

"!!" OTSG Number of Tubes Plugged Due to:

First Span Volumetric ICA Indications:* 428 Indications in Upper Roll Transitions: 51 Volumetric Indications in Freespan: 2 Indications at UTS Secondary Face: ** 1 Administratively Plugged Due to Tube ID Damage Caused by Repair Efforts:_ 1 TOTAL: 483

  • Three additiorud tubes mthfrst sjusn IGA stre plugged due to upper roll transition irulicatioru, and are counted in the roll traruition category. Only one of these three(B-44,42) had a repairable IGA indication. The other tuo tB-105,67 and B-114,47) hadfrst span IGA irulicatiora less tium 40% throughsu!!,

" One additiorud tube (R-73.66) had an trulication at the secondarypce of the llTS but is aho had indicatiora in the roll transition region arul h accountedpr in that category.

For the tubes in "II" OTSG with first span pit-like IGA, the breakdown of reasons for plugging are provided:

Tubes with an indication 240%: 311 Tubes with a non guantifiable indication: 65 Tubes with a MVI identified 12 Tubes with > 10% throughwall growth: 41 Tubes plugged for repairable indications in another region of that tube: 2

-TOTAL: 431

' MVI stands for Multiple Volumetric Indication ITS 5.7.2.c. Srecial Report 97-05 Page 8 of 9 Summer IW7 Inspections

U.S. Nucle:r Regulitory Commission

. 3F1297 22 Note that these counts do not represent the total number of these types or indications _ in the generator. ~ De tubes with first span pit-like IGA were sorted into the categories based on -

lthis hierarchyt

^

1, 240% throughwall e

2. high frequency bobbin NQl.
3. MVI identified on MRPC
4. .

growth indicated by regrestion technique sizing-5.- tubes plugged for non first span IGA reasons l - A complete listing of inspection results for plugged tubes in "B" OTSG is provided in Appendix 6.

t 1

ITS 5.7.2.c. Special Report 97-05 Page 9 of 9 Summer 1997 Inspections

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U.S. Nuclear Pcgulatory Commission 3F1297 22 l

ITS 5.7.2.c.

SPECIAL REPORT 97-05 APPENDIX 1 "B" OTSG FIRST SPAN GROWTH ASSESSMENT

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