ML19319C223

Forwards RO NP-32-77-15

ML19319C223
Person / Time
Site:	Davis Besse
Issue date:	09/12/1977
From:	Jonathan Evans TOLEDO EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19319C224	List: ML19319C223 ML19319C237
References
NUDOCS 8002060788
Download: ML19319C223 (1)

Text

^n__..__...________..._. _ - . _ _ _ _ _ . _ _ _ . _ _ . _ _ _ _ _ _ _ . .

.' ~ ^ ,

/

m

/ \

b tot FD0 EDISGN Scpeceber 12, 1977 Docket No. 50-346 License No. NPF-3 Mr. James G. Keppler Regional Director, Region III WQ ,

[

Offico of Inspection and Enforcement - -

U. S. Nuclear Regulatory Cormnission D

.'A 799 Roosevelt Road _ m a/ a Glen Ellyn, Illinois 60137 Daar Mr. Kcppler*

Reportable occurrence NP-32-77-15 Davia-Besse Nuclear Pnwnr station Unit 1  !

Date of Occurrence: Augur.t 22, 1977  !

F.nclosed find three copies of T.icensee Event Report NP-32-77-15 with n supple-mental information sheet, which is belug submitted in ni ordance with Technical

( Specification 6.9 t.o provide 14 day written notification of the subject occur-O rence. I Tours truly l

(j4

. ack Evsinx

• tation Soperintendent Ihvis-Besae Nuclear Powcr Station JGE/JRL/1.jk Enclosures cc: Dr. F.cnst vol gurou, Director Office of Inspection and Enforcement Encl: 40 copies Licensee Event Report 40 co-les Supplemental Information Sheet Mr. William G. Mcdonald, Director Offico of Management Infomation and Program Control ,

P.nc1: 3 copies Licensco Event Report g g d O Jg7 3 copies supplemental intornation Sheet

. 2 copics Telecopied Report v .

THG TOLFDO ED$CN COMPANY EDICON PLA7A 200 MADISON AVENUE TOLEDO. (IHIO 43G52

. .. ,m. n .

goo,qo 6 o 71

S

/

/ TOLEDO EDISON COMPANY DAVIS-BESSE UNTT ONE NUCLEAR POWER STATION

/ S

_U__PPLEMENTAT. TUFORMATTON FOR T.ER NP-32-77-15 Dp ,

D n

o 3 JL' pD 9Y DATE OF EVENT: p.agust 22, 1977

d. _ _

d]

FACILITY: Davis-Besse Unit 1 IDENTIFICATTON OF OCCUR 9f3CE: T.oss of two Relative Position Indicator Channels in one Control Rod Group.

Conditions Prior tn Occurrence: 'Ihe pinnt. wan in Mode 2, with Power (MLTI) = 0. and Load (MWE) = 0.

Description of Occurrence: On August 22, 1977, at 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br /> during the performanen

, of ST $099.01, "MIscellahous Instrument. shift check", it was discovered that t'.:o Relative Posit.iun Indient. ion Channel n (RPT) in Control Rud Group 6 indicated rcro percent withdrawn. Absolute Position Indications (APT) for rhnnn two control rods (Rods 6 and 11 of Group 6) indicated 21% withdrawn. Since there were two RFI'm inoperabic in one group, this put the Unit in vinintion of Technical Specification 3.1.3.3 and its corresponding action statement. The unit was pinend in llot Standby (Mode 3) at 1850 hours0.0214 days <br />0.514 hours <br />0.00306 weeks <br />7.03925e-4 months <br /> on August 22, 1977, per Tuchnical Specification 3.0.3.

is was not. determined to be immediately reportable until September 6, 1977 at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> during the report preparation.

Dr,signation_of,jpparent cause of Occurrence: The cause of this occurrences unn sub-ccquently detci,nined to be component failurcs'. In t.hc cane of Group 6, Rod 6. the API /RPT. select relay was faulty. In the case of Group 6, Rod 11. the AP7/FPT sc1ces. ,

ralay was sticking, l 1

l

, kis]vsis of Occurrence: There was no danger to the health and nafety of the public )

or station personnn1. The unit was placud in the Hot St.andby Mode and oni.y the indication was defective. The control rods were operab]c.

Corrective Action: The API /RPI select relay of Group 6. Rod 6 was replaced. The ralay on Group 6, Rod il van cycled several t.imes and now operates properly. The supplier, Diamond Power, was contacted and is investigating the probicm.

Failure Data: There have been two prior occurrences of control rnd indicatton l i

failures, one due to a loose connector and the other caused by a f aulty relay.

T*

.v )

w t-

- - ..