ML20070Q149

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Forwards Steam Generator Tube Plugging Rept,Providing Listing of Tubes Plugged During 1991 Refueling Outage Due to Eddy Current Indications & Tubes Plugged or Replaced
ML20070Q149
Person / Time
Site: North Anna Dominion icon.png
Issue date: 03/20/1991
From: Stewart W
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
91-146, NUDOCS 9103280210
Download: ML20070Q149 (26)
v • d • e


Text

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Yll(OINIA 151.100T)(10 AND l'OWII14 COMI'ANY lllCllMON D. YlltOINIA OllD 61 March 20,1991 i U.S. Nuclear Regulatory Commission Serial No.91-146 Attention: Document Control Desk NES/lSl/IBC: R0 Washington, D.C. 20555 Docket No. 50 338 License No. NPF 4 Gentlemen:

VlHGINIA ELECTRIC AND POWER COMPANY UORTH ANNA POWER STATION UNIT 1 STEAM GENER ATOR TUBE PLUGGING REPORT North Anna Unit 1 recently completed its 1991 refueling outage. During the cutage, we completed eddy current examination of all three steam generators. As required by Technical Specification 4.4.5.5.a, this letter provides a summary of the tube plugging activities performed during the outage.

Attachment 1 provides a listing of those tubes that were plugged during the outage due to eddy current indications. In addition to the tube: plugged due to indications, several other tube plug related activities were accomplisned during the outage. Due to the concern for tube plug integrity, tube plugs with suspect heat numbers were removed and new plugs installed. Attachment 2 provides a listing of tubes for which the plugs were replaced. Also, several tubes had previously been plugged with sentinel plugs as a preventative measure due to a concern for susceptibility for U-bend fatigue. The plugs for most of these tubes were removed and the tubes returned to service. Attachment 3 provides a listing of those tubes from which plugs were removed. These tubes were previously identified in our letter to the NRC, Serial No.90-274, dated June 21,1990. This letter informed the NRC of our intent and provided justification for removal of these plugs and returning the tubes to service. Attachment 4 provides a summary of the current tube plugging levels in each steam generator.

Should you have any questions or require additional information, please contact us.

Very truly y rs, W. L. St

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Senior ice President - Nuclear ii i

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Attachments

1. North Anna Unit 1 Steam Generators Tubes Plugged Summary
2. North Anna Unit 1 Steam Generators Plugs Repaired
3. North Anna Unit 1 Steam Generators Tubes Returned to Service
4. North Anna Unit 1 Steam Generators - Tube Plugging Levels Sumrnary oc: U.S. Nuclear Regulatory Comrnission Region ll 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Lesser NRC Senior Resident inspector North Anna Power Station l

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ATTACHMENT 1 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA -UNIT 1 STEAM GENERATOR TUBES PLUGGED

SUMMARY

REFUELING OUTAGE -- 1991

Virginia Electric and Power Company North Anna Power Station Unit 1 Steam Generators A, B, & C Tubes Plugged Summary The following tables list those tubes in the North Anna Unit 1 Steam Generators which were plugged during the 1991 refueling outage.

Table No.1 A: Tubes plugged in Steam Generator A.

3 Table No.18: Tubes plugged in Steam Generator B.

Table No.1C: Tubes plugged in Steam Generator C.

1

Table No.1 A Steam Generator A A total oi one hundred ninty (190) tubes were plugged in Steam Generator A during the 1991 refueling outage.

The following tubes were plugged based on eddy current indications:

Ban Column Bo.g Column 4 4 32 26 2 5 38 26 10 5 *" 2 27 11 5 "* 8 27 10 6 20 27 13 6 28 27 4 9 16 28 9 9 18 28 14 9 33 28 17 9 17 29 2 10 18 29 21 10 22 29 4 11 9 30 24 12 16 30 4 13 17 30

  • 31 13 20 30
  • 14 14 35 30 25 16 8 31 4 17 18 31
  • 28 18 9 32 *,* "

3 19 17 32 18 19 18 32 36 21 3 33 6 22 9 33 35 22 14 33 6 23 19 33 14 23 28 33 12 24 9 34 13 24 19 34 16 24 30 34 39 24 14 35 7 25 23 35 16 25 24 35 20 25* 39 35 11 26 10 36 *"

23 26 11 36

Table No.1 A- q Steam Generator A j Bgg Column - Bon Column -  !

14 36 25- 50 23 36 5 51 34 36 28- 51

.12 37 52 14 37 13 52  ;

21 '37 14 52

'25 37 f.2 52 33 37 24 52 9 38 *" :30 :52  ;

10 38 "* 3 53  :

12 8 18 38 10 53' *"

2 .39 16 53 4 39 18 53 25 39 27 5 3 '-

6 40 31- 53' 13 40 32- 53 '

16 40 33 53 21 40

  • 5 54' 27 40 6 54 28 40 25- 54 31 41 29 'E4' 32 41 34 :54 6 42 38- :54 19 42
  • 40- 54

- 23- 42 10 55 15 43 26- 55 22 43 32 -: 55 23 43- -- 24 -56 32 43 27 56 12 44= 33- 56_

17 44 4 9 45 *" - :29 '57 -

14 45- 14 '58 8 46 23 58 14 46 10 59 *"

24' 14 7 30 -59 33 48' 35 59

-45 48 15 60-11- 49 5 16 49 4 162 25 49 -13 -62 33 49- 25 62 4- 50 2' 63 7 50 41 63 15 50 6 64 20 50 23 64 Page 2 of 3 I -- -

., , , , _ _ _s_m

Table No.1 A Steam Generator A Hgg Column How Column 2 66 17 74 11 66

  • 27 74 3 68 16 76 40 69 20 77 6 70 11 78 "*

7 70 24 81 8 70 5 83 11 71 6 83 37 71 29 83 9 72 17 91 4 73 8 92 10 74

  • 7 45 "

Stabilizers installed on hot leg side of these tubes.

Tube plugged and stabilized by mistake.

Tubes scheduled to be restored to service this outa;:o (i.e., plugs removed during this outage). However, the tubes were inspected and replugged due to eddy current indications or other anomalies.

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. - - _ . . , . _ . _ . . - . - . - . . . . . - . . - . - . - - - - .. ~ . - - . . - . ~ -

- Table No.1B l

l Steam Generator B l

l A total of one hundred fifty six (156) tubos were plugged in_ Steam Generator B during the 1991 refuei;ng outage -

The following tubes were plugged based on eddy current indications:

, Bow C.plumn 80.g Column 3 2 -17 37 4 2 27 37 3 7 3 38 7 7 4 -38' 2 8 5 38 2 -9 12 38 5 9* 14 38 2 10 19 38 2 12 21 38:

9 -12 3 39 19 13 4 39 11 14 " 6 39

  • 6 - 15
  • 12 39 11 15- -37 39 25 15 5 40-9 16 11 40-l 23 16 20 40 * -

7 18 -31 40 10 19 11 41 10 20 .21 41 15 20 25 41 16 23- 27' 41 37 23

  • 5 42 5 24 -11 J42-7 25 15 42 17 25 2 43

-7 30 6 43 5 32 7 43-15 33 12 43 21 35 17 43 3 36 27 43~

14 36 29 43 16 36 2 44 3 37 3- 44 10 37 17 44 15 37 31 44

l Table No.1B Steam Generator B

[10.w QQluma Bow Column 5 45 27 57 12 45 29 57 17 45 9 58 22 45 21 58 21 46

  • 27 5C 25 46 27 59 7 47 44 59 24 47
  • 36 60 21 48 11 61 22 48
  • 38 62 24 48 22 63 8 49 4 64 22 49
  • 11 34 24 49 17 66 14 50 38 66 22 50 11 68 23 50 9 69 25 50 7 70 5 51 8 70
  • 12 51 35 70 19 51 2 71 l 25 51 2 74 29 51 10 74
  • 2 52 35 74 6 52 17 75 13 52
  • 37 75 16 52 15 78 25 52 7 80 30 52 29 80 39 52 7 81 44 52 11 82 14 53 16 84 27 53 24 84 4 54 2 85 28 54 7 85 26 56 2 86 27 56 7 86 9 57 5 87 13 57 12 88 14 57 4 89 25 57 2 90 26 57 2 93 Stabilizers installed on hot leg side of these tubes.

Tube pulled for evaluation.

Page 2 of 2

Table No.1C Steam Generator C A total of two hundred sixty one (261) tubes were plugged in Steam Gonerator C during the 1991 refueling outage.

The following tubes were plugged based on eddy current indications:

83 Column fgtw Column 3 3 6 26 10 5 "* 13 26

  • 11 7 14 26 6 8 i6 26 10 8 19 26 11 8 3 27 17 8 5 27 7 9 20 27 6 10 14 28 28 10 18 28 11 11 19 Ed
  • 16 11 22 28 5 12 13 29 7 14 19 29 10 14 20 29 25 14 3 30 16 15 12 30 1C 16 14 30
  • 3 17 19 30 12 18 20 30 l 21 18 24 30 32 18 16 31 19 19 18 31 8 20 19 31 16 20 21 31
  • 7 22 10 32 "*

l 11 22

  • 15 32 3 23 16 32 11 23 22 32 t 10 24 *" 29 32 14 24
  • 17 33
  • 5 25 18 33 10 25 *,* " 22 33 17 25 6 34 22 25 16 34 39 25 18 34

l Table No.10 Steam Generator C Bon Column Bow Column 24 34 29 44 25 34 3 45 19 35 12 45 22 35 13 45 1 35

  • 24 14 45 18 36 18 45 19 36
  • 24 45 21 36 45 45 2 37 15 46 11 37 23 46 19 37
  • 25 46 21 37 32 46 24 37 8 47 27 37 9 47 *,*"

25 38 18 47 {

27 38 20 47-17 39 25 47 1 19 39 14 48

  • i 20 39 23 48 22 39 24 48 25 39 32 48  !

29 39 33 48 l 2 40 12 49 18 40 32 49 19 40

  • 17 51 23 40 19 51 24 40 25 51
  • 28 40 31 51 2 41 7 52 5 41 13 52
  • 7 41 21 52 20 41 23 52 23 41 20 53 24 41 25 53 26 41 17 55 41 41 25 55 3 42 26 55 16 42 2 56 19 42 13 56 24 42 17 56 25 42 27 56 27 42 28 56 18 43 29 56 25 43 9 57 31 43 17 57 19 44 19 57 24 44 26 57 Page 2 of 4 V

Table No.1C Steam Generator C Hon Column Sqw Column 28 57 23 71 5 58 28 71 14 58 35 71 25 58 8 72 14 59

  • 11 72 16 59 12 72 17 59 13 72 25 59 2 73 26 59
  • 4 73
  • 31 59 6 73 13 60 7 73 14 60 10 73 17 60 11 73
  • 1 23 60
  • 18 73 26 60
  • 10 74 14 61
  • 5 75 21 61 7 75
  • 26 61
  • 20 75 14 62 7 76 24 62 10 76
  • 14 63 14 76 7 64 16 76

' 13 64 27 76 15 64 10 77

  • 26 64 18 77 27 64 5 78 2 65 11 78 7 65 13 78 13 65 6 79 25 65 10 79 6 66 28 79
  • 22 66
  • 2 80 23 66 6 80 31 66 7 80 4 67 10 80 11 67 5 83 5 68 17 83 33 68 18 83 4 69 8 84 5 69 16 84 8 69 3 85 20 69
  • 7 87 22 69 2 90 41 69 7 AD 11 70 11 90 29 70 16 90 Page 3 of 4

Table No.1C Steam Generator C Hgg ColumD Baw Column 12 93 *" 9 46 "

2 94 i

Stabilizers installed on hot leg side of these tubes.

Tubo plugged and stabilized by mistake.

Tubes scheduled to be restored to service this outage (l.o., plugs removed during this outage). However, the tubes were inspected and replugged due to eddy current indicationc or other anomalles.

Page 4 of 4

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ATTACHMENT 2 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA UNIT 1 STEAM GENERATOR PLUGS REPAIRED REFUELING OUTAGE 1991 1

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Vltginia Electric and Power Company 4

North Anna Power Station Unit 1 Steam Generators A, B, & C The following tables list those tubes in North Anna Unit 1'for which the plugs were removed due to the potential for plug degradation and the plug replaced during the 1991 refueling outage.

Table No. 2A: Tubes for which plugs were repaired in Steam Generator A.-

Table No. 28: Tubes for which plugs were repaired in Steam Generator B, Table No. 20: Tubes for which plugs were repaired in St$am Generator C.

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Tablo No. 2 A Steam Generator A The plugs in a total of sixty six (66) tubes were repaired in Steam Generator A during the 1991 refueling outage.

Han Column Haw Column 5 1 10 48 11 2 5 49 12 2 16 50 15 3 20 51 13 4 23 52 3 9 23 53 5 10 26 54 6 12 30 54 7 18 20 55 7 19 4 56 7 21 2 58 15 21 3 59 3 23 29 59 4 23 2 60 19 23 5 60 11 24 14 60 18 25 27 61 3 26 4 63 4 26 40 63 5 26 11 64 7 26 12 65 16 27 4 68 17 28 6 68 16 36 4 69 20 36 3 70 3 39 18 71 5 39 9 75 4 40 18 78 5 40 3 84 3 41 11 84 21 42 5 86 3 44 25 87 7 48 17 90

Table No. 2 B Steam Generator B The plugs in a total of seventy seven (77) tubes were repaired in Steam Generator B during the 1991 refueling outage.

Bog Column Bqg Column 10 2 18 44 11 2 11 45 11 3 26 45 12 3 9 46 13 3 16 46 2 5 26 46 2 6 14 47 2 7 18 47 3 11 11 48 34 18 12 48 7 19 23 48 2 21 28 51 3 21 5 53 7 22 15 53 9 23 16 53 24 23 30 53 3 25 13 54 2 28 16 54 7 28 26 54 9 30 4 56 39 33 10 60

. 9 34 11 60 l 13 34 41 66 9 35 12 67 13 35 35 68 24 35 11 70

6 37 10 73 l 14 39 24 73 28 39 34 74 2 40 34 75 3 40 8 77 13 40 4 79 7 41 14 83 24 41 25 87 25 42 2 92 11 43 10 93 34 43 11 90 9 44 12 93-16 44 l

t . .

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! Table No. 2C Steam Generator C The plugs in a total of one hundred thirty four (134) tubes were repaired in Steam Generator C during the 1991 refueling outage.

Bow Column How Column

(

l 11 2 21 35 3 4 2 36 9 5 6 36 4 6 27 36 3 8 16 37 4 8 2 38 24 8 3 38 3 9 26 38 5 9 14 39 6 9 11 41 3 10 13 41 2 11 2 43 3 11 14 43 6 11 45 43 4 12 32 45 11 12 2 47 29 15 24 47 12 16 31 47 6 17 9 48 12 19 21 48 15 20 26 48 19 21 25 49 20 21 34 49 4 22 2 50

! 6 22 8 50

! 6 23 9 50 4 24 10 50 2 26 11 50 3 26 12 50 5 28 13 50 4 29 14 50 12 29 8 51-2 30 12 51 22 31 13 51 21 32 15 51 19 33 34 51 l 20 33 8 52 9 35 9 52

Table No. 2C Staam Generator C flgn Column Baw Column 10 52 23 67 11 52 3 69 12 52 3 71 14 53 6 71 13 54 15 71 14 54 18 71 15 54 31 71 17 54 6 72 33 54 6 74 46 54 7 74 3 55 8 74 13 55 6 75 4 56 14 77 24 67 7 81 8 58 11 81 2 59 20 81 3 59 24 81 4 59 25 81 1 60 6 85 3 60 13 90 4 60 3 91 6 60 6 91 l 8 60 6 92 9 60 11 93 2 61 3 61 4 61 6 61 30 62 8 63 25 64 8 66 10 66 5 67 l

Page 2 of 2

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  1. 4 ATTACHMENT 3 4

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA UNIT 1 STEAM GENERATOR TUBES RETURNED TO SERVICE REFUELING OUTAGE 1991

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Virginia Electric and Power Company North Anna Power Station Unit 1 Steam Generators A, B, & C The following tables list those tubes in North Anna Unit 1 for wh!ch the plugs were removed and the tubes returned to service during the 1991 refueling outage.

Table No. 3A: Tubes returned to service in Steam Generato. A.

Table No. 38: Tubes returned to service in Steam Generator B.

Table No. 3C: Tubes returned to service in Steam Generator C,

Table No. 3 A Steam Generator A A total of seventy (70) of the attempted (80) tubes wet successfully returned to service in Steam Generator A during the 1991 refueling outage.

Eqw Column Bqw Column 9 2 9 47 10 2 10 47 8 3 11 47 10 3 9 48 11 3 10 52 12 3 11 52 13 3 12 52 8 4 12 53 10 4 9 54 11 4 10 RA 10 7 11 54 11 7 12 54 10 8 9 59 11 8 11 59 9 14 9 60 9 24 11 60 10 32 9 61 10 33 10 61 9 35 11 61 10 35 9 66 10 37 10 72 11 37 10 73 11 38 10 76 10 39 10 77 11 39 10 78 9 40 12 78 10 40 10 79 11 40 11 79 9 41 12 79 10 41 10 93

, 11 41 11 93 9 42 12 93 9 43 10 44 10 45 9 46 10 46 11 46

Table No. 3 B Steam Generator B There were no tubes returned to service in Steam Generator B during the 1991 refueling outage.

l l

Table No. 3C 1

Steam Generator C l l

l A total of fifty (50) of the attempted (56) tubes were successfully returned to service in Steam Generator C during the 1991 refueling outage.

HQW Column Eqw Column 10 2 11 30 12 2 9 31 10 3 10 31 10 4 11 31 10 6 11 32 9 15 9 'j7 9 17 9 42 10 18 9 44 9 19 9 45 10 19 10 45 10 20 9 46 10 22 10 46 10 23 10 47 9 24 10 48 11 24 9 49 9 25 9 56 11 25 9 61 10 26 9 63 11 26 9 64 10 27 9 65 9 28 9 66 10 28 9 67 10 29 9 68 9 30 9 75 l

6 10 30 10 93 l

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ATTACHMENT 4 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA UNIT 1

SUMMARY

TUBE PLUGGING LEVELS IN EACH STEAM GENERATOR REFUELING OUTAGE - 1991 l

s . .

Virginia Electric and Power Company North Anna Power Station Unit 1 I

The foilowing table is a summary of tube plugging levels for Unit 1 steam generators:

~

A B C Previously Plugged Tubes 353 269 445 Tubes 80 0 56' Returned to Service

    • Tubes Plugged 190 156 261
in 1991 Outage i Total Tubes Plugged 463 425 650

% Plugged 13.7 12.5 19.2

  • Includes recovered tubes which required replugging.

" Includes new indications and recovered tubes which required re plugging.

Excludes repaired plugs.

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