ML20097A283

Special Rept 91-007,reporting Results of Fourth SG Tube Inservice Insp Completed by Westinghouse on 911024 of SGs a & C

ML20097A283
Person / Time
Site:	Wolf Creek
Issue date:	05/29/1992
From:	Bailey J WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
91-007, 91-7, NO-92-0130, NO-92-130, NUDOCS 9206020253
Download: ML20097A283 (4)

Text

.

0 h

~

W@ NUCLEAR LF CREEK OPERATING COR ,

John A. Bailey Vice President 5**"'

May 29, 1992 NO 92-0150 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 Vashington, D. C. 20555

Subject:

Docket No. 50-482: Special Report 91-007 Gentlemen The attached Special Report is being submitted in accordance with Technical Specification 4.4.5.5 b concerning the results of Wolf Creek Generating Station's fourth steam generator tube inservice inspection.

Very truly yours, x-fJfM/\h/M[* /

John A. Bailey 3

Vice President Operations-JAB /aem Attachment cci A. T. Howell (NRC), w/a R. D. Martin (NRC), w/a G. A. Pick (NRC), w/a W. D. Reckley (NRC), w/a e

L3.ne~v v t) d s  ;=

9206020253 920529 A/.- l PDR ADOCK 05000402 //

. ~.. dox 411/ Burlington, KS 66839 / Phoae: (316J 364 8831 An Equal Opportunity Employer M F HC' VET?

h'

Attachment to NO 92-0430 Page 1 of 2 1

SPECIAL REPORT 91-007 FOURTH STEAM GENERATOR TUBE INSPECTION RESULTS This teport is being submitted pursuant to Technical Specification (T/S) 4.4.5.5.b and 6.9.2 to report the results of the fourth steam generator tube inservice inspection.

Th? fuurth steam generator tube inservice inspection was completed by Westingbouse Electric Corporation on October 24, 1991, during the fifth Refueling Outage. This inspection included steam generators (S/G) 'A' and 'C'.

A total of 2,192 tubes were inspected, and a total of two tubes were plugged in S/G 'C' as discussed in Special Report 91-004, which was transmitted by letter NO 91-0313, dated November 1, 1991. This inspection did not identify any tubes which were required to be plugged in S/G "A'. Included in this inspection effort were 15 tubes (three in S/G 'A' and 12 in S/G 'C") which had been previously identified as having indications requiring re-inspection during this inservice inspection effort. The inspection results of all indications of greater than 202 are listed in section 3 of this report.

Thi+ includes any indications found in the 15 tubes that had previous indications.

NRC Bulletin 89-01, with supplements, requires that mechanical tube plugs manufactured from Inconel 600 with certain heat numbers be removed prior to the expiration of their predicted time to fail. As a conservative measure, all of the Inconel 600 mechanical tube plugs were removed from steam generators 'A' and "C" during this inspection. In addition, all Inconel 600 mechanical tube plugs are planned to be removed from steam generators 'B' and 'D' during the sixth refueling outage scheduled for Spring, 1993.

Ten Inconel 600 mechanical tube plugs (6 hot leg and 4 cold leg) were removed from six tubes in S/G 'A' and eight mechanical plugs were removed from four tubes in S/G 'C', All of the tubes in S/G 'A' were replugged. In i S/G 'C', two tubes were returned to service after eddy current testing indicated acceptable results. They had been plugged preventively with indications of less than 40%. All mechanical plugs installed were manufactured of Inconel 690.

3. Number and Extent of Tubes Inspected:

A. Steam Generator "A's A total cf 1.565 tubes were inspected full length.

B. Steam Generator 'C's A total of 1,227 tubes were inspected full length. A total of 253 tubes were inspected from tube end cold (TEC) to the top support plate of the cold leg side (7C).

l f

t 1

s Attachment to NO 92-0130 Page 2 of 3

2. Identification of Tubes Plugged:

Row Column Leg A. Steam Generator 'A's Replugged after plug removal 17 11 H 52 66 H 28 61 H 28 61 C l 28 65 H 28 65 C 28 103 H 4 28 103 C 51 78 H 51 78 C i B. Steam Generator "C":

Replugged after plug removal 54 40 H l 54 40 C

) 14 17 H 14 17 C Hew pluggable indications 49 84 H ,

49 84 C 1 49 88 H 49 88 ,C

3. Location and Percent of Wall Thickness Penetration for Each Indication f of an Imperfection (Note: Multiple listings of the same tube are the

( result of ne re than one indication in that tube):

Key For Indication Lists fH. #C (# = number) of Support Plate at Leg or Cold Leg Side AVf Anti-Vibration Bar (i = number)

P Tube Plugged, following I of Wall Thickness Loss Indication I of Wall Thickness Loss Inch (4-) Distance Measured from reference point from (AV Par Baffle Plate. Tube Support Location Plate, etc.)

Attachment to NO 92-0130 Page 3 of 3 Tube Indications in Steam Cent'rator 'A' Indication Inch (+)

Row column Location / Lee (t of Wall Thickness) From Location 45 25 AV5 23 0.00 45 32 AV4 26 0.00 45 35 AV2 21 0.00 45 35 AV3 20 0.00 45 35 AV4 37 0.00 43 38 AV3 34 0.00 51 78 AV2 37P 0.00 51 78 AV3 37P 0.00

$1 78 AV4 49P 0.00 51 78 AV5 29P 0.00 39 80 AV6 37 0.00 39 86 AV4 28 0.00 Tube Indications in Steam Generator "C' .

Indication Inch (+)

Roy, Column Location /Len (! of Wall Thickness) From Location 38 19 TSC 30 9.26 49 36 AV3 35 0.00 49 84 AV3 43P 0.00 49 84 AV4 26P 0.00 49 88 AV3 26P 0.00 49 88 AV4 42P 0.00 49 88 AVS 20P 0.00 40 103 AV4 25 0.00 40 103 AV5 35 0.00 36 108 AV3 27 0.00 36 108 AV4 21 0.00 35 109 AV4 29 0.00 35 110 AV2 22 0.00 35 110 AV5 38 0.00

- _