ML20207R703

Part 21 Rept Re Potential Defect in Static Exciter Voltage Regulator (Sevr) Reset Design.Recommends Mod to Control Circuits to Energize Sevr Upon Receipt of Emergency Start Signal.Mods Will Be Completed by 870331

ML20207R703
Person / Time
Site:	Harris, Rancho Seco, Bellefonte, 05000000
Issue date:	03/11/1987
From:	Guntrum B TRANSAMERICA DELAVAL, INC.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-87, REF-PT21-87-061-000 PT21-87-061-000, PT21-87-61, NUDOCS 8703180043
Download: ML20207R703 (4)

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-o Imo Delaval Inc.

Enterprise Engine Didslon Enterprise Way and 85th Avenue D Oakland, CA 94ti21 l'. O. Ikix 21til l

415-577-7400 l

March 11, 1987 Director, Office of Inspection and Enforcement US Nuclear Regulatory Commission Washington, DC 20553

Dear Sir,

In accordance with the requirements of Title 10 Chapter 10, Code of Federal Regulations, Part 21, IMO Delaval Inc. hereby notifies the Commission of a potential defect in a component of a DSR and DSRV Standby Diesel Generator.

These exists a potential problem with the static exciter voltage regulator reset design.

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IMO Delaval has supplied DSR and DSRV engines with this potential defect to the following sites:

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UTILITY SITE SERIAL NO.

MODEL Carolina Power & Light Shearon Harris 74046/49 DSRV 16 TVA Bellefonte 75080/83 DSRV 16 SMUD Rancho Seco 81015/16 DSR 48 The SEVR system is designed to de-energize upon receipt of a normal shutdown signal and to reset when the engine speed falls below 200 RPM.

If an emergency is received before the engine coasts below this reset speed, the engine will accelerate to its normal operating speed of 450 RPM. The exciter would not have been energized, however, thereby preventing the generator from providing any output voltage.

This circuitry was an intentional design feature that allowed an engine / generator shutdown without overheating the generator field.

IMO Delaval recommends that the subject control circuits be modified to energize the SEVR upon receipt of an emergency start signal.

We are in the process of designing these modifications and will complete this effort by March 31, 1987.

All of the information necessary to implement these changes will be forwarded to the individual sites no later than April 15, 1987.

Since action is required by others, we cannot estimate when corrective action will be completed.

8703180043 870311

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Page 2 March 11, 1987 U.S. Nuclear Regulatory Commission A copy of this letter will be sent to the affected sites as indicated by the cc list.

Our evaluation of this matter was concluded on March 9, 1987.

Sincerely,

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linues

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Bruce C. Guntrum Manager, Quality Assurance BCG/dfa cc:

Carolina Power & Light Co.

Shearon Harris Nuclear Plants P.O. Box 101 New Hill, North Carolina 27562 Attn:

Mr. R.A. Watson, Vice President Mr. L.I. Loflin, Mgr.

Harris Plant Engineering Mr. N.J. Chiangi Manager, Q.A.

Tennessee Valley Authority - Bellefonte W7C126, 400 West Summit Hill Drive Knoxville, Tennessee 37902 Attn:

Mr.

1.L. Beltz Sacramento Municipal Utility District P.O. Box 15830 Sacramento, CA 95813 Attn:

L.R. Keilman Nuclear Engineering Dept., M.S. 32

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Page 3 March 11, 1987 U.S. Nuclear Regulatory Commission bec:

Taiwan Power Company Maanshan Nuclear Power Project P.O.

Box 9, Hengchun 924 f

Pingtung Hsien, Taiwan, Republic of China Attn:

Mr.

Y.C. Chow Plant Superintendent Korea Electric Power Corporation Kori, Jang-Ahn Myun Yangsan Kun, Kyung-Nam Korea Attn:

Mr. Yoon, B.K.

KNU 5 & 6 Site Manager Korea Electric Power Corporation Gaesari, Hong-Nong Myun Yeong Gwang Kun, Jeon-Noon Korea Attn:

Mr. Kim, Jong Sok KNU 7/8 Site Manager e

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