ML20064H449

RO 50-368/78-17 on 781201:Emergency Feedwater Train B Response Time Was Less Conservative than Assumed in the Safety Analysis Due to Unknown Cause.Emergency Feedwater Train B Reset to a Valve Consistent W/Safety Analysis

ML20064H449
Person / Time
Site:	Arkansas Nuclear
Issue date:	12/14/1978
From:	Shively C ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML20064H447	List: ML20064H442 ML20064H449
References
NUDOCS 7812200229
Download: ML20064H449 (4)

Text

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I- Reportable Occurrence Report No. 50-368/78-17

2. Report Date: December 14, 1978 3. Occurrence Date: December 1,1978 4 Facility: Arkansas Nuclear One-Unit 2 Russellville, Arkan;as

5. Identification of Occurrence:

During Mode 3 operation, prior to initial criticality, it was determined that the response time for Emergency Feedwater Train B, as listed in T. S. Table 3.3-5 Items 7B & 88,was less conservative than that assumed in the Safety Analysis. There have been two previous similar occurrences (see 50-368/78-14 and 50-368/78-10). j l

6. Conditions Prior to Occurrence:

Steady-State Power Reactor Power 0 MWth c

Hot Standby X Net Output 0 Mwe Cold Shutdown Percent of Full Power 0 g Refueling Shutdown Load Changes During Routine Power Operation 0 Routine Startup Operation Routine Shutdown Operation f

other (specify) Mode 3 operation before initial criticality

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7. Description of Occurrence:

The EFW Train B setpoint as specified in T. S. Table 3.3-5 Items 78 &

88 was found to be less conservative than assumptions used in the Safety Analysis.

78122002 @ 23

Reportabic Occurrence Report No. 50-368/78-17 S. Designation of Apparent Cause of Occurrence:

Design Procedure Manufacture Unusual Service Condition Including Environmental Installation /

Construction Component Failure (See Failure Data)

Operator Other (specify) Delayed communication between NSSS vendor and AE while performing reanalysis of the EFW and associated elec-trical systems.

9. Analysis of Occurrence: ,

Since the reactor core had not been made critical, the nonconservative set-point did not endanger the health and safety of the public as the plant had never been operated in a mode wh.ich would require EFW to control or mitigate a postulated accident.

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Reporta'ule Occurrence Report No. 50-368/78-17

10. Corrective Action:

Upon discovery of the nonconservative setpoint, the setpoint was changed to a value within the assumptions of the Safety Analysis.

A new analysis has been perfonned which substantiates the. values that currently exist in the Technical Specifications.

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11. Failure Data:

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