ML20129G658

Discusses Eddy Current Indications in CE Designed Welded SG Tube Sleeves for Plant,Units 1 & 2.Request for Addl Info Encl

ML20129G658
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	09/30/1996
From:	Shiraki C NRC (Affiliation Not Assigned)
To:	Johnson I COMMONWEALTH EDISON CO.
References
TAC-M95183, TAC-M95184, NUDOCS 9610030118
Download: ML20129G658 (4)

Text

'

, Kra 4 UNITED STATES

• ye .)*

1. s NUCLEAR REGULATORY COMMISSION f WASHINGTON, D.C. 20555-0001 k +

8

% ,,s,,, September 30, 1996 Ms. Irene Johnson, Acting Manager Nuclear Regulatory Services Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 500 Downers Grove, IL 60515

SUBJECT:

EDDY CURRENT INDICATIONS IN COMBUSTION ENGINEERING DESIGNED WELDED STEAM GENERATOR TUBE SLEEVES - ZION NUCLEAR POWER STATION, UNITS 1 AND 2 (TAC NOS. M95183 AND M95184)

Dear Ms. Johnson:

During the Prairie Island Unit 1 (PI-1) January 1996 steam generator (SG) tube inspection, 61 eddy current (EC) indications were found in the upper sleeve weld region of Combustion Engineering (CE) welded tubesheet sleeves. These indications were characterized as single or multiple circumferential indications or volumetric indications. All sleeved tubes with the circumferential indications were removed from service (four tubes were pulled; seven tubes were plugged). The sleeved tubes with volumetric indications were evaluated for location. Sleeved tubes with volumetric indications located by EC below the centerline of the sleeve weld were removed from service; the remaining sleeved tubes were left in service (one tube was pulled; 16 tubes were plugged; 34 tubes were left in service).

The five pulled sleeve / tube assemblies were examined by CE with oversight by the Electric Power Research Institute (EPRI). The results were documented in a March 1996 CE report, " Verification of the Structural Integrity of the ABB CEN0 Steam Generator Welded Sleeve," CEN-628-P, Revisioa 01-P. The conclusion of the report was that the EC indications were the result of either or both of two weld conditions termed " incomplete fusion" or " sleeve outside diameter (00) suckback" caused by improper cleaning of the parent tube prior to welding. Although present since installation, the nondestructive examination (NDE) methods used at the time were not sensitive enough to detect these weld conditions. There was no evidence of inservice induced degradation. .The faulty installation process also affected sleeve / tube assemblies at the following plants: ANO-2, Ginna, Kewaunee and Zion 1 and 2. The staff requires additional information to determine the Commonwealth Edison Company's (Comed) 30 TRE CEW COPY g o

030038 ,

9610030118 960930 PDR ADOCK 05000295 P PDR

1 l

i I

i I. Johnson- ]

I a

plans with respect to inspection and repair of these sleeved tubes during the current Zion Unit 2 outage and the Unit 1 outage currently scheduled for March

'1997. .

Sincerely, i

/s/

Clyde Y. Shiraki, Project Manage .

Project Directorate III-2  :

Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation i

Docket Nos. 50-295, 50-304 l

Enclosure:

RAI cc w/ encl: See next page l DISTRIBUTION: i 3 Docket-File"'

'PUBLIC' PDIII-2 r/f , i 1

JRoe-(JWR)

EAdensam (EGAl)

-RCapra CMoore CShiraki OGC, 015-B18 ACRS, T2-E26 i' LMiller, RIII i

l i

i

-DOCUMENT NAME: G:\ZI95183.LTR Ta roosive a copy of this document, Indicagin the box: "C* = copy without enclosures *E" = Copy with enclosures "N" = No copy 0FFICE PM:PDIII-2 l0 ' LAM @ II-2 l (.V D:PDIII-2 l - E. l l  !

NAME CSHIRAKI: avl 3/ CMf)0RE RCAPRA F ,

DATE 09/g/96 09/$/96 09/10/96 l l 0FFICIAL: RECORD COPY  !

i i

1

. h ,.

• I. Johnson Zion Nuclear Power Station l Unit Nos. I and 2

! Commonwealth Edison Company cc:

Michael I. Miller, Esquire 1

[ Sidley and Austin- .

l One First National Plaza l Chicago, Illinois 60603 )

Dr. Cecil Lue-Hing l Director of Research and Development Metropolitan Sanitary District of Greater Chicago 100 East Erie Street l Chicago, Illinois 60611 Phillip Steptoe, Esquire Sidley and Austin One First National Plaza Chicago, Illinois. 60603 Mayor of Zion j Zion, Illinois 60099 j Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive -l Springfield, Illinois 62704  !

U.!i. Nuclear Regulatory Commission Zicn Resident Inspectors Office 105 Shiloh Blvd.

Zion, Illinois 60099 Regional Administrator ,

U.S. NRC, Region III 801 Warrenville Road Lisle, Illinois 60532-4351 Station Manager Zion Nuclear Power Station 101 Shiloh Blvd.

Zion,-Illinois 60099-2797 Document Control Desk-Licensing Commonwealth Edison Company l 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 l

l l

i

i .

I 1

• i l .

l j REQUEST FOR ADDITIONAL INFORMATION i

i 1. During the Zion Unit 2 SG tube inspections in the current refueling 1- outage, what is Comed's intention regarding inspection of the upper weld ,

in the existing CE designed welded sleeves? Include inspection scope l and nondestructive examination methodologies to be used.  :

2. What is Comed's intention regarding disposition of sleeved tubes with j weld zone indications? Include past practice and present intentions.

If Comed intends to leave weld zone indications (WZIs) in service, i provide the basis for the acceptability of this practice including the 1 l uncertainty in locating the exact position of volumetric flaws. l l

- 3. The staff is currently reviewing a TS amendment dated September 3, 1996, '

that will add certain portions of the new CE Topical Report to the TS.

Commonwealth Edison also docketed a letter dated September 18, 1996,

, that discusses certain technological enhancements it has adopted, within j the requirements of the TS, that have not changed the sleeve design or the reliability of the sleeving process. In its letter of September 18, 1996, Comed also docketed its intention to submit a TS amendment that i will refer to the process enhancements contained in the letter.

Exclusive of these reviews and commitments, is it Comed's intention to adopt the new CE Topical Report in its entirety? If so, how will Comed

incorporate this topical report into its TS for future sleeving

. operations?

9 ENCLOSURE