05000029/LER-1987-003, Forwards LER 87-003-00

Forwards LER 87-003-00

ML20205D816
Person / Time
Site:	Yankee Rowe
Issue date:	03/20/1987
From:	St Laurent N YANKEE ATOMIC ELECTRIC CO.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 8703300490
Download: ML20205D816 (1)

LER-2087-003, Forwards LER 87-003-00

Event date:
Report date:
0292087003R00 - NRC Website

text

,. . . ..

YANKEE ATOMIC ELECTRIC COMPANY r.i.on n.t<,s, 2< ,2e, Star Route, Rowe, Massachusetts 01367

.YANKEiE March 20, 1987 U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Attention: Dr. Thomas E. Murley, Regional Administrator

Subject:

Licensee Event Report 50-29/87-03 Reactor Scram - High Main Coolant Pressure

Dear Sir:

In accordance with 10 CFR 50.73(a)(2)(iv), the attached Licensee Event Report is hereby submittea.

Very truly-y6iTys, War? A/ , //'/4~

Normand N. St.datfrent Plant Superintendent ELM /nm Enclosure cc: [3] NSARC Chairman (YAEC)

[1] Institute of Nuclear Power Operations (INPO) 8703300490 DR 870320 ADOCK 05000029 PDR ,

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LICENSEE EVENT REPORT (LER)

DOCKET NUMSER (29 PAGE G PACILITY asAast it)

Yankee Nuclear Power Station, Rowe, Massachusetts ol5tol0Iol0l2l9 1 loFl 011 TITLE let Reactor Scram - High Main Coolant Pressure EVENT DATE (95 LER NUMSER q$4 REPORT DATE 473 OTHER F ACILITIES INVOLVED ISI DOCKET muusERis)

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NIAsE TELEPMONE NUMSER ARE A CQQE Edwin L. May, Senior Plant Engineer 4 ,1 ,3 4,2,4, ,5,2,6l1 COMPLETE ONE LINE FOR EACM COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 CJAISE SYSTEM COMPONENT " yy A"hC-R a q,TR s' CAU$E $Y$ TEM COMPONENT M AC. R O PR M

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I l l l l l ! I I I i  ! ! I SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAY YEAR SUOMts$10N YES tit ven, comte EXPECTED SU360!S$lON DA TEl NO l l l AuTR Acr et ,, . saco a. s .. .ee<e. wy sn .n. . avnn ,u .e oel At 0001 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, on February 18, 1987, with the plant in mode 1 at 100 percent power with no rod motion in progress, the Control Room operators observed a decrease in reactor power and that No. 2 control rod's position lights indicated that it had dropped. The operators immediately began to reduce generator load to restore the main coolant system Tave per plant procedure. At 0003 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> the reactor protection system initiated an automatic scram as the result of a high main coolant pressure condition. The high main coolant pressure occurred because load reduction by the operator overcompensated for the power reduction from the dropped rod. The NRC was notified via ENS at 0101 hours0.00117 days <br />0.0281 hours <br />1.669974e-4 weeks <br />3.84305e-5 months <br /> February 18, 1987.

The root cause of this event was determined to be an open circuit in the I

stationary gripper coil for No. 2 control rod. The coil stack was replaced in kind and the control rod was satisfactorily tested. The coil is a style / type

1. 366C390; rating 129 volts DC; unit manufactured by the Westinghouse Corporation. This is the first occurrence of this nature. Each refueling l outage every control rod coil is inspected and resistance values taken to insure operability. No other corrective actions are deemed necessary at this time.

, All systems performed as intended during this occurrence. There was no adverse I

effect to the public health or safety as a result of this event.

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