ML19308D585

LER 78-024/01T-0:on 780504,B&W 10CFR21 Rept of Possible Safety Concern Re Loss of Ground in Reactor Protection Sys Found to Apply to CR-3.Channel Trip Not Caused.Mod Initiated to Include Monthly Ground Check in Testing Procedure

ML19308D585
Person / Time
Site:	Crystal River
Issue date:	05/05/1978
From:	Cooper J FLORIDA POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19308D581	List: ML19308D580 ML19308D585
References
LER-78-024-01T, LER-78-24-1T, NUDOCS 8003040987
Download: ML19308D585 (2)

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FETTI I This will confirm a report ma ,

frTTl l o f f ic e a t 1435 on 4 May 1978. At 1415 on 4 May 1978 CR-3 [

io p i lplant staff was informed that the 10 CFR 21 report received ,

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,from B&W, of a. possible safety concern, with regard to the io ai 1 loss of ground within the Reactor Protection System does apply, lo i sl I to CR-3. Redundancy N1. .No hazard to the health and safety  ;

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,,,.,,RPS ground check in the Reactor Protective System Functional , j i 3,,,ii Testing Procedure.  ;

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SUPPLEMENTARY INFORMATION 1, - port No.: 50-302/78-024/0lT-0

2. cility: Crystal River Unit #3

3. Occurrence Date: 4 May 1978 4 Report Date: 5 May 1978

5. Identification of Occurrence:

Possible safety concern with regard to the loss of ground within the Reactor Protection System.

6. Conditions Prior to Occurrence:

Mode 6 refueling.

7. Description of Occurrence:

I At 1415 CR-3 plant staff was informed that the 13'CFR 21 report received '

from B&W does apply to the Reactor Protection System (RPS) at CR-3.

The report stated that one RPS channel may experience a loss of ground l co its instrument common without the loss of ground being evident.

Given this condition, a single postulated failure in one channel can leave the RPS in an unanalyzed condition. An evaluation of the RPS ,

System has indicated that the loss of ground may not cause a channel 1

-s trip, as was previously speculated.

8.k-sasignation of ApparentI Cause: .. .

B&W has determined that a 'lo s s o f RP S ground say.not cause a channel trip as previously analyzed.

9. Analysis of Occurrence:

No hazard to the health and safety of the public as plant is defueled.

10. Corrective Action:

Modification 78-4-7 has been initiated to include a monthly check to assure that the RPS ground has not been losr, in the Reactor Protective System Functional Testing Procedure (SP-110).

10. Failura Data:

First occurrence of this event.

Tolocopied 3/5/78 - 1:00 pm by SR7 - CR-3 Verified 5/5/78 1:10 pm by Gerald James Atlanta xcj-% T.Rodgers i IP. Stewart k_sIH.Wessman