ML19256A879

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LER 78-018/01T-0 on 781219:during Normal Power Operation, Power Range Channel 44 Failed,Causing 20% Turbine Runback. Failure of Power Designs,Inc,Model UPMP-X54W Power Supply Caused Instrument to Fail
ML19256A879
Person / Time
Site: Point Beach NextEra Energy icon.png
Issue date: 12/29/1978
From: Burstein S
WISCONSIN ELECTRIC POWER CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19256A878 List:
References
LER-78-018-01T, LER-78-18-1T, NUDOCS 7901160266
Download: ML19256A879 (2)


Text

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w9r. 4366 U. S. NUCLEAR REGULATORY COMMISSION (77)

LICENSEE EVENT REPORT 1

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80 7 8 60 69 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h O 2 lDuring normal full power operation at 0712 hours0.00824 days <br />0.198 hours <br />0.00118 weeks <br />2.70916e-4 months <br /> on 12-19-78. nower rangd 10l31 Channel 44 failed, carsing a 20% turbine runback. Full redundancy was l0 l4 j g restored at 0722 when ICP 10.2 was implemented. This event is report- 1 O s lable in accordance with T. S. 15.6.9.2.A.2. The event also caused a I O c lbrief drop in reactor coolant system pressure to 2193 during the i O 7 l transient. T. S. 15.3.1.A.4.A.2 states that pressure may not drop belowl O a 1 2220 psig during operation at 2250 psia. LER 78-010/0lT-0 is a similar j DE CODE S BC E COMPONENT CODE SUBC DE SU DE 7

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40 43 44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i O l Failure of the Power Designs , Inc., Model No. UPMP-X54W oower supply I i i Icaused the instrument to fail. The power supolv was replarna and I t-11 :2i lreturned to service at 1102 hours0.0128 days <br />0.306 hours <br />0.00182 weeks <br />4.19311e-4 months <br /> on 12-22-78. A brief dron in cressurni

[TTT1 is normal during a turbine runback. This larcer decrease was caused by I i i 4 Ithe pressurizer proportional heaters beino temporarily out-of-servico I

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s ATTACHMENT TO LICENSEE EVENT REPORT-78-018/0lT-0 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 1 Docket 50-266 During normal full-power operation at 0712 hours0.00824 days <br />0.198 hours <br />0.00118 weeks <br />2.70916e-4 months <br /> on December 19, power range Channel 44 failed, causing a 20%

turbine runback and reducing the degree of redundancy of the power range ins;rumentation below the required level of 2, as stated in Technical Specification Table 15.3.5-2. This event is reportable in accordance with Technical Specification 15.6.9.2.A.2. To re-establish the required degree of redundancy for all reactor trip functions, ICP 10.2, " Removal of Safeguards or Protection Sensors from Service" was implemented at 0722 hours0.00836 days <br />0.201 hours <br />0.00119 weeks <br />2.74721e-4 months <br />. The event also caused a brief drop in reactor coolant system pressure to 2193 psia during the transient.

Technical Specification 15.3.1.A.4.A.2 states that pressure may not drop below 2220 psia during operation at 2250 psia.

A return to full-power operation was commenced at 0722 hours0.00836 days <br />0.201 hours <br />0.00119 weeks <br />2.74721e-4 months <br />, following completion of ICP 10.2. Full power was achieved at 0758 hours0.00877 days <br />0.211 hours <br />0.00125 weeks <br />2.88419e-4 months <br />.

Failure of the Power Designs, Inc., Model UPMP-X54W high-voltage power supply has been diagnosed as the cause of the instrument failure. The power supply was replaced at 1102 hours0.0128 days <br />0.306 hours <br />0.00182 weeks <br />4.19311e-4 months <br /> on December 22, and the power range channel was returned to operation.

A brief drop in reactor coolant system pressure is expected during a turbine runback transient. The larger than normal drop in prassure in this event, however, was caused by the pressurizer proportional heaters being out of service at that time for maintenance reasons.