ML20236F547

Documents 871020 Telcon W/Util Re Unit 2 Circuit Breaker Pole Shaft Weld Failure

ML20236F547
Person / Time
Site:	Sequoyah
Issue date:	10/23/1987
From:	Hood D Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
TAC-65955, TAC-65956, NUDOCS 8711020197
Download: ML20236F547 (4)

Text

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UNITED STATES o.

g NUCLEAR REGULATORY COMMISSION 5

l W ASHINGTON, D. C. 20555 OCT 2 31987 Docket Nos.:

50-327 and 50-328 l

l LICENSEE:

Tennessee Valley Authority FACILITY:

Sequoyah Nuclear Plant, Units 1 and 2

SUBJECT:

Record of Telephone Conversation Regarding Sequoyah 2 Circuit Breaker Pole Shaft Weld Failure (TACS 65955/65956)

On October 20, 1987, the NRC (D. Hood, V. Hodge and D. Sellers) called the Tennessee Valley Authority (E. Pugh, J. Hosmer, D. Briggs and M. Adams) to discuss the two broken fillet welds on the cole shaft assembly of the cir-cuit breaker that energizes the emergency fire protection pumps for Sequoyah Unit 2.

TVA's preliminary findings from the engineering analysis by its Materials Engineering Section are discussed in J. B. Hosmer's memorandum dated July 10,1987 (same as enclosure 2 of D. Hood memorandum," Sunrnary of September 23, 1987 Neeting on Westinghouse Switchgear Failures," dated October 2, 1987). TVA responded to several staff questions:

0.

Type of circuit breaker?

A.

Westinghouse DS-416, being used in Class IE 480 volt service 0.

Date of discovery?

A.

April 11, 1987 0.

Which two welds failed?

A.

Fillet welds for middle two levers called the Y phase lever (i.e., the center pole lever and the antibounce lever).

In the July 10, 1987 Hosmer memorandum, these are called " cams".

Q.

Behavior of breaker with broken welds?

A.

Technician issued a work request reflecting assumption that the charging motor had failed, that breaker would not operate, and that arcing had been observed at the shutdown board.

Later observation revealed a 2 phase problem probably associated with operation of the Y-phase lever (i.e., the center moving contact assembly). Observed erratic operation of the fire pump. The 2 phase problem suggests that the center moving contact assembly was free to move independently of the pole shaft which drives the other two moving contacts.

Q.

How repaired?

A.

Substituted a pole shaft from spare parts

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OCT 2 3199 Q.

Measurements.of failed welds (length and leg size)?

A.

Not available during call, but see photographs attached to Hosmer's July 10, 1987 memorandom. Welds are unaltered. Will send better copies to NRC.

O.

How many breakers of DS series in TVA plants?

A.. For each Sequoyah unit, counted on shutdown board 150 Class IE and 6 non-class IE.

Number at other TVA plants not available during call.

l Q.

What data was supplied by Westinghouse regarding related failures or alternate engineering justification for short, undersized welds?

I A.

None J

0.

What is used for reactor trip breakers?

A.

Westinghouse DB-50s.

Q.

Any related failures at TVA or elsewhere?

A.

None at TVA. Aware of McGuire 2 and Calvert Cliffs 1 failures.

0 Darl S. Hood, Project Manager Project Directorate II-3 Division of Reactor Projects, I/II cc:

E. Pugh, TVA J. Hosmer, TVA D. Briggs, TVA M. Adams, TVA J. Jelovich, W

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)J V D30 PD#MI-3/DRP-I/II PD#II-3/DRP-I/II DHood/mac DHood, Acting PD 10/zI/87 10/ p /87

p l,;

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' Mr. S. A. White j

Tennessee Valley Authority Sequoyah Nuclear Plant 1

-cc:

General Counsel Regional Administrator. Region _II Tennessee Valley Authority' U.S. Nuclear Regulatory Commission 400 West. Summit Hill Drive 101 Marietta Street, N.W.:

E11 B33

. Atlanta, Georgia 30323 Knoxville,. Tennessee 37902 Resident Inspector /Sequoyah NP Mr. R.'L. Gridley c/o U.S. Nuclear Regulatory Commission

- Tennessee Valley Authority 2600 Igou. Ferry Road SN 1578 Lookout Place Soddy Daisy, Tennessee 37379 Chattanooga, Tennessee 37402-2801 Mr. Richard King Mr. H. L. Abercrombie c/o U.S. GA0 Tennessee Valley Authority 1111 North Shore Drive Sequoyah Nuclear Plant Suite 225, Box 194 P.O.-Box 2000 Knoxville, Tennessee 37919 Soddy Daisy, Tennessee 37379 4

Tennessee Department of Mr. M. R. Harding Public Health

. Tennessee Valley Authcrity-ATTN:

Director, Bureau of Sequoyah Nuclear Plant Environmental Health Services P.O. Box 2000 Cordell Hull Building 1

-Soddy Daisy, Tennessee 37379-Nashville, Tennessee 37219

'Mr. D. L. Williams Mr. Michael H. Mobley, Director Tennessee Valley Authority Division'of Radiological Health i

400 West Summit Hill Drive T.E.R.R.A. Building

- W10 B85 150 9th Avenue North Knoxville, Tennessee 37902 Nashville, Tennessee 37203 County Judge Hamilton County Courthouse Chattanooga, Tennessee 37402 i

1 CO-9* ?

Ih, MEETING

SUMMARY

DISTRIBUTION OCT 2 31987 CDocket-File' >

NRC Participants f

NRC POR D. Hood L PDR

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Hodge l

NSIC D. Sellers PRC System PD#II-3 Rdg

. Project Manager D. Hood

'M.

Duncan K. Naidu J. Richardson A. Toalston.

E. McKenna S. West T. Peebles, RII

0. Kolostyak W. Troskoski (MNBB 6113)

OGC-Bethesda ACRS (10)

_0THERS bec: Licensee & Service List

M L

October 27, 1987 I

(de No. 50-324 DISTRIBUTION bDocket filea R.

NRC & LOCAL PDRs y E, E. Utley PD21 r/f kior Executive Vice President SVarga sr' Supply and Engineering & Construction Glainas solina Power & Light Company ESylvester it Office Box 1551 OGC-B sigh, North Carolina 27602 DHagan GPA/PA

.r Mr. Utley:

ACRS(10)

(

JECT:

SURVEILLANCE REQUIREMENTS RELATED TO ANTICIPATED TRANSIENT WITHOUT SCRAM (ATWS) RECIRCULATION PUMP TRIP INSTRUMENTATION (TAC N0, 66338)

Nuclear Regulatory Commission has requested the Office of the Federal Register publish the enclosed " Notice of Consideration of Issuance of Amendment to ility Operating License and Opportunity for Prior Hearing " This notice

]

ates to your application for amendment dated September 29, 1987, which would s

'ise the Technical Specifications for.the Brunswick Steam Electric Plant, t 2,.to change the surveillance requirements related to the anticipated transient

hout scram recirculation pump trip instrumentation.

s notice is being issued bectiuse the proposed amendment is too complex to mit a' preliminary no significant hazards consideration determination to made without detailed review.

Sincerely,

=

~-

lsi Ernest D. Sylvester, Project Manager Project Directorate 11-1 Division of Reactor Projects I/II

losure:

stated w/ enclosure:

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