ML17263A914
| ML17263A914 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie, Ginna  |
| Issue date: | 01/25/1995 |
| From: | Mecredy R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Andrea Johnson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9502060122 | |
| Download: ML17263A914 (7) | |
Text
PRIORITY (ACCELERATED RIDS PROCESSli
'<<REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NB'R:9502060122 DOC.DATE: 95/01/25 NOTARIZED: NO FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G
50-335 St. Lucie Plant, Unit 1, Florida Power
& Light Co.
AUTH.NAME AUTHOR AFFILIATION MECREDY,R.C.
Rochester Gas
& Electric Corp.
RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R.
Project Directorate I-3 (PD1-3)
(Post 941001)
DOCKET N
05000244 05000335 P
SUBJECT:
Advises that util has reviewed impact of cracking of W Alloy 600 mechanical plugs, discovered in Nov 1994 at St Lucie Unit l,on operation of Ginna NPP.Items considered as part of review listed.
DISTRIBUTION CODE:
A001D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal:
General Distribution 0
NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72).
05000244 I
RECIPIENT ID CODE/NAME PDl-3 LA, PD1-3 PD JOHNSON,A COPIES LTTR ENCL 1
1 1
1 1
1 RECIPIENT ID CODE/NAME PD2-2 LA PD2-2 PD NORRIS,J COPIES LTTR ENCL 1
1 1
1 1
1 INTERNAL: ACRS NRR/DRCH/HICB NRR/DSSA/SRXB OGC/HDS3 6
6 ~F'I-EE CENTER=-0~
1 1
NRR/DSSA/SPLB 1
1 NUDOCS-ABSTRACT 1
0 1
1 1
1 1
1 EXTERNAL: NOAC 1
1 D
U NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO RfDUCE iVKSTE! CONTACTTHE DOCL'WIENTCONTROL DESK, ROOKI Pl-37 (EAT. 504-~OS3 ) TO ELIXIINATEYOI.'R i'ANILPl<Oil DISTRIBU'I'IONLISTS I:OR DOCI.'P,IEi'I'S 5'Ol: DON"I'L'ED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 20 ENCL 19
4ND ROCHESTER GASANDELECTRIC CORRORAT1ON
~ 89 EAST AVENUE, ROCHESTER, N. Y 14649-0001 ROBERT C. MECREDY January 25, 1995 Vice President Hvcieor operations U.S. Nuclear Regulatory Commission Document Control Desk Attn:
Allen R. Johnson Project Directorate I-3 Washington, D.C.
20555 AREA CODE 716 5'-2700
Subject:
Failure of Westinghouse Alloy 600 Steam Generator Tube Mechanical Plugs R.
E. Ginna Nuclear Power Plant Docket No. 50-244 Reference (a):
Unanticipated Crack in a
Particular Heat of Alloy 600 Used for Westinghouse Mechanical Plugs for Steam Generator
- Tubes, dated December 22, 1994
Dear Mr. Johnson:
As requested by the NRC at the NRC/Westinghouse/industry meeting of December 22, 1994 held in Rockville, Maryland, Rochester Gas
& Electric has reviewed the impact of the cracking of Westinghouse Alloy 600 mechanical
- plugs, discovered in November 1994 at St. Lucie Unit 1, on operation of the Ginna Nuclear Power Plant.
A description of this issue is discussed in Reference (a).
The following items were considered as part of the Rochester Gas
& Electric review of the mechanical plug issue:
1.
Present status of Westinghouse Alloy 600 mechanical plugs installed at the Ginna plant.
2.
Review of the safety concerns associated with installed mechanical plugs at the Ginna plant.
3.
Impact of the St.
Lucie Unit 1 cracking on mechanical plug effective life as quantified by WCAP-12244 4.
Impact of the St.
Lucie Unit 1 'racking on Ginna scheduled outage maintenance plans related to Alloy 600 mechanical plugs.
Our assessment of these items is provided in Attachment l.
Very truly yours, 0100 ~-"'i JFDi364 P
22 950i25 PDR ADOCK 05000240 PDR q,~Pro~~~
~~
Robert C. Mecr dy
~ c r IP E, ~
5
xc:
Mr. A'lien R. Johnson (Mail Stop 14D1)
Project Directorate I-3 Wash'ington, D.C.
20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Inspector
ATTACHMENT 1
~ ASSESSMENT OF ST ~ LUCIE UNIT 1 CRACKING ON GINNA Status of Westinghouse Mechanical Plugs Presently, Ginna Station has 176 Westinghouse Alloy 600 mechanical plugs installed.
All of these plugs are installed in Steam Generator B.
These plugs were installed at Ginna between 12/79 and 10/82.
To date no leakage in Westinghouse Alloy 600 mechanical plugs has been discovered at Ginna.
None of the installed plugs are from the NX-2387 heat batch which exhibited cracking at St.
Lucie.
The specific heat batches installed at Ginna and the number of installed plugs in each batch are summarized below.
Heat Batch NX-9789 NX-1660 NX-2386 TOTAL 40 14 33 87 40 16 33 89 80 30 66 176 Safety Concern Associated with Plug Cracking After the North Anna plug top failure in 1989 due to cracking in Westinghouse Alloy 600 mechanical plugs (documented in NRC Bulletin 89-01 Supplements 1 and 2), Westinghouse performed a
safety assessment to justify continued operation for all affected plants, including Ginna Station.
That evaluation and the resulting Justification for Continued Operation (JCO) is documented in WCAP-12244, Rev.2.
The WCAP-12244 assessment demonstrated that there was no safety concern for continued operation for any of the plants which had installed mechanical plugs Additionally, for plants like Ginna Station which have a
partial depth tubesheet
- design, WCAP-12244 demonstrated that a plug top release could not result in a puncture of a steam generator tube as had been experienced at North Anna.
Due to the short length of the expanded tube in the tubesheet for the partial depth design, a plug top release would become lodged in the tubesheet.
Consequently, WCAP-12244 demonstrated that there was no safety concern associated with continued operation of the installed Alloy 600 mechanical plugs at Ginna.
The mechanical plug cracking observed at St. Lucie Unit 1 is viewed as another example of the susceptibility of Alloy 600 mechanical plugs to primary water stress corrosion cracking (PWSCC).
As such it is comparable to the other batches of mechanical plugs which were identified to be susceptible to PWSCC following the North Anna failure.
The cracking PAGE 1
V ATTACHMENT 1 ASSESSMENT OF ST.
LUCIE UNIT 1 CRACKING ON GINNA discovered at St.
Lucie Unit 1
does not invalidate the original safety assessment and JCO performed by Westinghouse and documented in WCAP-12244, Rev.
- 2. Therefore, since the WCAP-12244 safety assessment and JCO is applicable to Ginna, Rochester Gas
& Electric concludes that no new safety concerns are associated with continued operation of Ginna.
C.
Assessment of Revisions to WCAP-12244 As a result of the St. Lucie Unit 1 cracking, Westinghouse is in the process of revising estimated mechanical plug effective lifetimes and the status of installed mechanical plugs for all plants.
Westinghouse has informed Rochester Gas
& Electric of their intent to issue Addendum 3 to WCAP-12244 in January, 1995. In support of this activity Rochester Gas
& Electric has provided Westinghouse with an updated status of the Westinghouse Alloy 600 mechanical plugs presently installed at Ginna.
After Addendum 3 to WCAP-12244 has been issued, Rochester Gas
& Electric will review the changes made to the WCAP and assess their impact on proposed steam generator maintenance plans for the Alloy 600 mechanical plugs presently installed in the hot.
leg of Steam Generator B at Ginna.
Rochester Gas
& Electric will also assess the impact of the revised WCAP on previous responses made to the NRC as a result of IE Bulletin 89-01.
D ~
Effect on Future Maintenance Plans Following a
review of the revised
- WCAP, Rochester Gas Electric willprovide the NRC with a summary of 1995 Refueling Outage planned maintenance activities for the Westinghouse Alloy 600 mechanical plugs installed in th'e hot leg of Steam Generator B. This summary will be provided to the NRC 30 days prior to the start of the 1995 Refueling Outage, currently scheduled to commence March 26, 1995.
If deferment of plug repair/replacement beyond the revised effective plug life (as documented in Addendum 3 to WCAP-12244) is planned, Rochester Gas
& Electric will provide the NRC with a justification to support the proposed outage maintenance activities.
PAGE 2
0 0
V l