ML17325B254
| ML17325B254 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/20/1989 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| AEP:NRC:1096, IEB-89-001, IEB-89-1, NUDOCS 8906290111 | |
| Download: ML17325B254 (10) | |
Text
gccE~RATED D'WKBU'nON DEMONST STION SYSTEM REGULA"'u. Y ZNFORMA ON DISTRIBUTIOh SYSTEM (RZDS) 4
-ALEXICH,M.P.
Indiana M'chigan Power Co. (formerl
~ Indiana 6 Michigan Ele RECZP. NAM" RECIPIENT AFFILIATION MUR:EY, Docume".." Control Branch (Document Control Desk)
SUBJ:-
- Forwards response o
NRC Bulletin 89-001, "Failure of westinghouse Steam Generator Tube Mechanical Plugs."
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TITLE: Bullet'n Res@or.se (50 DKT)
NOTES:
ACC.SSZON NBR.8906290111 DOC.DATE 89/06/20 NOTARIZED. YES DOCKET FACE: 50-315 Donald C.
Cook Nuclear Power Plant, Unit 1,, indiana 05000315 AUTH.NAME AUTHOR AFFILIATION
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Indiana Michigan Power Company P 0 Bo)" I66~
Z INDIANA NICHIGAN POWER AEP:NRC:1096 Donald C.
Cook Nuclear Plant Units 1 and 2
License Nos.
50-315 and,50-316
RESPONSE
TO NRC BULLETIN 89-01; FAILURE OF WESTINGHOUSE STEAM GENERATOR TUBE MECHANICAL PLUGS U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
20555 Attn:
T.
E. Murley June 20 1989
Dear Dr. Murley:
This letter provides our response to NRC Bulletin 89-01, entitled "Failure of Westinghouse Steam Generator Tube Mechanical Plugs,"
as it applies to the Cook Nuclear Plant.
The bulletin discusses problems with stress corrosion cracking of steam generator tube plugs supplied by Westinghouse and manufactured from four Inconel heats.
The specific information requested in the bulletin is provided in the attachment to this letter.
In summary, Unit 2 is operating with new steam generators and therefore has no mechanical-type plugs in service.
Unit 1 has 538 plugs from one of the suspect Inconel
- heats, divided evenly between the hot and cold legs.
The plugs installed in the hot legs have a lifetime estimate, as conservatively determined by Westinghouse, less than the length of the upcoming Cycle ll.
- However, the Unit 1 steam generator tubes are partially depth expanded within the tube sheet
- and, per Action 3 of the bulletin, remedial actions may be deferred until the next refueling outage.
The plugs will be repaired or replaced as necessary at the next refueling outage, which is presently scheduled to begin in late 1990.
Our response to NRC Bulletin 89-01 was requested to be made under oath or affirmation according to the provisions of Section 182a of the Atomic Energy Act of 1954, as
- amended, and 10 CFR 50.54(f).
As
- such, an oath is included with this letter.
M.
. Alexich Vice President 8906290111 85'0620 PDR ADOCN 05000315 G
PNU
Dr. T.
E. Murley AEP:NRC:1096 ldp Attachments cc:
D.
H. Williams, Jr.
W.
G. Smith,. Jr.
- Bridgman R.
C. Callen G. Charnoff A. B. Davis NRC Resident Inspector
- Bridgman NFEM Section Chief
ATTACHMENT TO AEP:NRC:1096 INFORMATION REQUESTED IN NRC BULLETIN 89-01
Attachment to AEP:NRC:1096 Page 1
This attachment provides the information requested by NRC Bulletin 89-01.
The responses are applicable to Unit 1 of the Cook Nuclear Plant.
Unit 2 is operating in its first cycle following replacement of all steam generators, and therefore has no mechanical plugs installed.
Item 1 Summar of Re uest Verify that information contained in WCAP-12244, Rev.
1 and Westinghouse letter No. NS-NRC-89-3432 is correct.
Specifically, verify the number of Westinghouse mechanical plugs installed in the hot and cold legs broken down by steam generator, heat number, and date of installation.
R~es onse The information contained in Westinghouse Report WCAP-12244, Revision 1 and the Westinghouse NRC letter dated May 1,
- 1989, was reviewed for each steam generator to verify the number of Westinghouse mechanical plugs installed in the hot and cold legs by number, heat number and date of installation.
No inconsistencies were found.
Our review identified discrepancies in the May 1, 1989 Westinghouse letter regarding power operation history and temperatures.
Westinghouse has recalculated the remaining effective full power days (EFPDs) for the Heat 4523 plugs using the revised data, as well as other refinements to the original analysis.
The new, data and calculation results for the Heat 4523 plugs are provided in the attached table, which is of the same form as the tables from the May 1, 1989 letter.
(Information considered proprietary to Westinghouse has been deleted from the table.)
The revised calculation results were factored into the response to item 2.a, below.
Item 2.a Summar of Re uest Estimate steam generator tube plug lifetime for plugs from Heats
- 3279, 3513,
- 3962, and 4523 based on the Millstone Unit 2 benchmark.
~Res onse There are no installed plugs from Heats
- 3279, 3513, or 3962.
Steam generator tube plug lifetime for Heat 4523 was evaluated
Attachment to AEP:NRC:1096 Page 2
/
by Westinghouse using the methodology from WCAP-12244, Revision 1 and adjusted to reflect the Millstone Unit 2 benchmark.
The results indicate that the plugs installed in the steam generator hot legs have a remaining lifetime of 353 EFPDs and the plugs installed in the cold legs have a
remaining lifetime of 9099 EFPDs.
s 3.
Item 2.b Summar of Re uest Implement appropriate remedial acti'ons (i.e., repair and/or replacement) for all plugs whose estimated lifetimes in Item 2.a do not extend to the next refueling outage.
~Res onse Unit 1 completed Cycle 10, has been refueled, and is currently preparing for start-up.
The remaining lifetime for the hot leg plugs of 353 EFPDs is less than the length of the next fuel cycle, which has an estimated duration of 428 EFPDs.
- However, under the provisions of item 3, below, remedial actions will be planned for implementation during the refueling outage at the end of Cycle 11, which is currently scheduled for late 1990.
4.
Item 2.c Summar of Re uest Prior to any plug repairs or replacement, addressees are reminded that their responsibilities under ALARA require analysis of the various plug repair or replacement methods available to determine which method will result in the lowest overall personnel radiation exposure while still remaining cost effective.
~Res onse Since repair or replacement actions are not necessary until fall 1990, specific plans for the activity have not been made.
- However, ALARA considerations will be addressed when formulating plans for the repair or replacement activity.
5.
Item 2.d Summar of Re uest Installation of Westinghouse mechanical plugs from Heats
- 3279, 3513,
- 3962, and 4523 should be discontinued.
Attachment to AEP:NRC:1096 Page 3
R~es onse'n May 7,
- 1989, steam generator eddy current tube examinations and pluggings were completed.
Westinghouse mechanical plugs'rom qualified Inconel 600 heats were used for plugging.
During the above-mentioned
- plugging, no plugs were used from the heats referenced by the bulletin (Heats
- 3279, 3513,
- 3962, and 4523).
Mechanical plugs'rom qualified material heats only will be used in the future, in either unit, to minimize susceptibility to primary water stress corrosion cracking (PWSCC)..
6.
Item 2.e Summar of Re uest Westinghouse mechanical plugs removed from steam generators, regardless of heat numbers should be examined for PWSCC on a.
sample basis for each heat.
~Res onse Should Westinghouse mechanical plugs be removed, a sample will be made available to Westinghouse to examine for the presence of PWSCC in order to facilitate Westinghouse in maintaining a
data base concerning the susceptibility of plugs to PWSCC.
7.
Item 3
Summar of Re uest Remedial actions at plants where the steam generator tubes are partially depth-expanded within the tube sheet may be deferred on a one-time basis to the next scheduled refueling outage if the outage that immediately follows receipt of this bulletin ends before October 1,
1989.
~Res onse The Unit 1 steam generator tubes are expanded for approximately 2.5 inches in the bottom of the tube sheet.
Remedial actions are therefore subject to the one-time deferral offered by this item.
8.
Item 4 Summar of Re uest Remedial actions for sentinel related mechanical plugs described above may be deferred on a one-time basis to the next refueling outage if the outage that immediately follows receipt of this bulletin ends before October 1, 1989.
Attachment to AEP:NRC:1096 Page 4
~Res ense This item is not applicable.
Sentinel plugs are not in service at the Cook Nuclear Plant.
Alloy 600 Hechanical Plug Date Revised: 6/14/89
+
+
+
+
+
~ +
~ ~ ~
+
IHSTALLATIOH DATA
(
Previous' Hew I
Teaperature(
I EFPD to minimm ligament I
(Remaining EFPD to minima lig(
Cycle
(
Cycle
(
Scaling
( Plug Hin.
( Previous cycle rate (Based on new cycle rate I
Plug HL (Temperature (Teeperature
(
Factor (A)( Size Lig.
( CHIL Other Applicable Rates(
EFPD ITUBESHEETI Plant Inst ¹ of Heat S/G or
(
(Deg.
F)
(
(Deg. F)
(-----------~ -(
Rate APR VGB CHIL
(
to
( NIL Other Applicable Rates/
JOIHT
(
Alpha Date Plug Ho.
¹ CL
(
HL CL
(
HL CL (Prev.
New
( (in) (mils)
(
(B)
(C)
(D)
(E)
( Date
( Rate APR VGB CHIL I
PROCESS I
AEP 7.87 69 4523 11 CL (600.0 536.0 (582.0 518.0 I
I.
I 4928 5506 434 '(
9099 10269 (Part. Roll/
AEP 7.87 90 4523 14 HL (600.0 536.0 (582 '
518.0
(
I 663 740 434
(
353 473 (Part. Roll/
AEP 7-87 86 4523 12 HL (600.0 536.0 (582.0 518.0
(
I 663 740 434
(
353 473 (Part. Roll (
AEP 7.87 90 4523 14 CL (600.0 536.0 (582.0 518.0
(
NE$TJNQIIQU$g
(
4928 5506 434
(
9099 10269 (Part. Roll/
AEP 7 87
- 69. 4523 11 HL (600.0 536.0 (582.0 518.0
(
PIIPPItyETA,It@
(
663 740 434
(
353 473 (Part. Roll(
AEP 7-87 24 4523 13 CL (600.0 536.0 (582.0 518.0
(
I 4928 5506 434
(
9099 10269 (Part. Roll(
AEP 7-87 24 4523 13 HL (600.0 536.0 (582.0 518.0
(
663 740 434
(
353 473 (Part. Roll/
AEP 7.87 86 4523 12 CL 1600.0 536.0 (582.0 518.0 I
I I
4928 5506 434
(
9099 10269 (Part. Roll (
HOLES:
(A) Based on T-hot = 622.5 deg F
(8) Growth rate based on Hillstone 2 data
0.073 mils/EFPD, for microstructure factor
1 (C) Growth rate based on Farley 2 data e 0.0922 mils/EFPD, for microstructure factor =
1 (D) Growth rate based on Horth Anna 2 data "-0.115 mi ls/EFPD, for microstructure factor "-1 (E) Growth rate based on Millstone 2 data
= 0.073 mils/EFPD, for microstructure factor = 4 or 16.
(1)
EFPD for heat 4523, for plugs installed 7-87 at AEp was calculate based on 15 EFpO at 90K power and 419 EFPD at 100X power.
T.hot for 90X power = 595 F. T.hot for 100/ power
= 600 F.
COUNTY OF FRANKLIN Milton P. Alexich,.being duly sworn, deposes and says that he is the Vice President of licensee Indiana Michigan Power
- Company, that. he has read the forgoing Response to NRC Bulletin 89-01; Failure of Westinghouse Steam Generator Tube Mechanical Plugs and knows the contents thereof; and that said contents are true'o the best of his knowledge and belief.
Subscribed and sworn to before me this ZO z ~
day of 198~.
NOTARY BLIC Ca>(V+88<q~~wan g-g-gl