ML19305A123

LER 78-012/01T-0 on 781209:primary Loop a Resistance Temp Detector Manifold Isolated to Replace Leaking Orifice Flange Gasket.Took 2 of 4 Overtemp & Overpower Temp Difference Channels Out of Svc.Caused by Personnel Error

ML19305A123
Person / Time
Site:	Point Beach
Issue date:	12/22/1978
From:	Burstein S WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19305A116	List: ML19305A115 ML19305A123
References
LER-78-012-01T, LER-78-12-1T, NUDOCS 7901040150
Download: ML19305A123 (2)

Text

N C FOR 366 U. S. NUCLEAR REGULATORY COMMISSION mi ,

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l 8 60 61 DOCKET NUMBER 68 69 EVENT DATE 14 75 f4EPORT DATE l EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l l lo l2l lWith the reactor just critical during an outage on 12-9-78, the crimarv l 4

l0 l3; l loop "A" resistance temperature detector manifold was isolated at 0730 l a

l l0 l4; th ours to replace a leaking orifice flange gasket. This took 2 of 4 I i

I O l si lovertemperature and overpower temperature difference channels out-of- I 10lcl1 service, leaving the minimum number of channels to trip (2). T. S. _J 4

[Ol7[ll5.3.5.C with T.

S. Table 15.3.5-2, Items 5 and 6, requires a hot Jhut- I

[Oisl ldown if the minimum number of operable channels (3) or degree of j SYSTEM CAUSE CAUSE O1 . V V COLE CODE SU8 CODE COMPONENT CODE SUBCODE SU3 CODE

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CAUSE DESCRIPTION AND CCRRECTIVE ACTIONS h j lijollThis event occurred due to an oversight on the part of C- oerating I

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NAVE OF PREPARER

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ATTACHMENT TO LICENSEE EVENT REPORT NO. 78-012/0lT-0 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 2 Docket No. 50-301 With the reactor just critical at zero power during a scheduled outage on December 9, 1978, the reactor coolant system (RCS) loop "A" RTD (resistance temperature detector) manifold was manually isolated at 0730 hours0.00845 days <br />0.203 hours <br />0.00121 weeks <br />2.77765e-4 months <br /> to replace a leaking orifice flange gasket. This removed two out of the four overtemperature AT and overpower AT channels from service and left only the minimum number of AT channels to trip (two) in service.

The reactor was taken subcritical at 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br /> to facilitate rod position indication calibration and then returned to zero power criticality at 1444 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.49442e-4 months <br />.

The RTD manifold was valved back into service at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> returning the instrumentation to full redundancy.

Technical Specification 15.3.5.C in conjunction with Items 5 and 6 of Technical Specification Table 15.3.5-2 requires a hot shutdown if the minimum number of operable channels (three) or the minimum degree of redundancy (two) cannot be met.

This event occurred due to an oversight on the part of the operating personnel. To prevent recurrence, operating personnel have been instructed to more carefully evaluate the effects of changing the position of reactor coolant system valves while the reactor is critical. Also, a copy of this licensee event report will be routed to all licensed operating personnel per normal plant practice.

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