05000338/LER-1978-051-01, /01X-1 on 780614:auxiliary Feedwater Pump start-up Delay Due to Improper Adjustment of Instantaneous Contracts on an Aquastat 2400 Series Relay

/01X-1 on 780614:auxiliary Feedwater Pump start-up Delay Due to Improper Adjustment of Instantaneous Contracts on an Aquastat 2400 Series Relay

ML19289C590
Person / Time
Site:	North Anna
Issue date:	01/16/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19289C589	List: 05000338/LER-1978-051, Forwards LER 78-051/01X-1 05000338/LER-1978-051-01, /01X-1 on 780614:auxiliary Feedwater Pump start-up Delay Due to Improper Adjustment of Instantaneous Contracts on an Aquastat 2400 Series Relay
References
LER-78-051-01X, LER-78-51-1X, NUDOCS 7901190097
Download: ML19289C590 (2)

LER-1978-051, /01X-1 on 780614:auxiliary Feedwater Pump start-up Delay Due to Improper Adjustment of Instantaneous Contracts on an Aquastat 2400 Series Relay

Event date:
Report date:
3381978051R01 - NRC Website

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Update Report - Previous Report Date 06-28-78 Virginia Electric and Power Company North Anna Power Station, Unit ilo.1 Attachment: Page 1 of 1 Docket No. 50-338 Peport No. LER/R0 78-051/0lX-1 pescription of Event From data generated by a Start-up test (Station Blackout) a 3 second delay in the starting of an auxiliary feedwater pur"p was discovered.

Probable Consequences of Occurrence The 3 second delay was not a serious' problem from a safety standpoint since the plant accident analysis requires the auxiliary feedwater be established in 60 sec. or less. Also there was no measurable delay in a manual start of the pump.

Cause of Occurrence The delay in the start of the auxiliary feedwater pump was determined to be due to an improper adjustment of the instantaneous contacts on an Agastat series 2400 relay.

The inmediate action was to adjust the contacts for instantaneous closure.

Scheduled Corrective Action This problem was reviewed and an inconsistency of design was discovered.

No certification cf seismic qualification could L'e found for these " add on" instantaneous con: acts and since the auxiliary feedwater system is a Seismic Class 1 system, a design deficiency was identified.

The architect engineer was notified and an E & DCR was issued to change this and all other seismic class 1 systems which use the " add on" instantaneous centacts.

These contacts were replaced with existing seismically qualified relay contacts and the systems functionally tested.

Action to Prrvent Pecurrence The action to prevent a recurrence of this problem is to attcyt to obtain a seismically qualified replacement for future applications.

Additional Information

It was also discovered that the Component Cooling Water Pumps secre af fected b3 the lack of certification for seismic qualification of " add-on" instantaneous contacts of Agastat Series 2400 rclays used in their control circuits.

These contacts were replaced with existing seismically qualified relay contacts.

The Component Coaling Water System is required during normal shutdown, but is not required to mitigate the consequences of a Loss of Coolant Accident.

The health and safety of the general public were not affected.