ML19319B773

RO NP-33-77-52:on 770807,auxiliary Feedwater Pump Turbine 1-1 Lost Speed Control.Caused by Relay Failure & Blown Control Power Fuse.Addl Relay Contacts Added in Series W/ Failing Contacts Increasing Breaking Capabilities by 770808

ML19319B773
Person / Time
Site:	Davis Besse
Issue date:	09/01/1977
From:	Chesko R, Lingenfelter J TOLEDO EDISON CO.
To:
Shared Package
ML19319B679	List: ML19319B678 ML19319B773
References
NUDOCS 8001270243
Download: ML19319B773 (3)

Text

. _ __ _ -_

6

. j

\ O. LICENSEE EVENT REPORT CoNinot stoCm i 1 ; tj G

mme .. ..~.....

' ,w <n.r

$j0 lH I DlB i S ilj 0 j i j 0l01 NlPIF!-1 0 I((

4 iljlil:1 o C... . m r ve.w;. ,,C...u_... .s. . ,.... ...,., ...

2i con i j L LLj LO f 5i Di. ; 0 3 1 4 i 1 6, i0 ,8 i 0;7 ;7,7 i 1 0,9;cil,7;M 7,

$d 9 60 56 64 69 Je 75 EVtNT DE SCAIPfloM

@t89 Auxiliary Feed Pump Turbine 1-1 was inoperable due to loss iof speed ,

1 "

gl control. This entered the starion into the Action Statemerit of  ;

7 89 "

@[ Technical Specification 3.7.1.2. (NP-33-77-52). ,

! l 3 39

8L i

' ha- t=< <e__..,,, c d i n .~'

~-

a y ~% y"4 IXl9 v.,,, ,,,o Eic89 i50si is_J 7 61

[ Rl E IL [ AIY l X I 12 is

@43 44 ij es g.g CAL,St OtScain tion Q ! The causes of the loss of speed control were relay failure and a  ;

i

. g l, blown control power fuse.

7 89 f

7 89 g

% s aTu'i  % *ovet e o s Os%Covt a v Ot%Cnsetic.e 8 (J_j 1010101 l NA'see . sta tus osshj*v l ( ( J,A J

7 0 9 RO s2 tJ ** 41 46 80 4 D of s'. g e Mouae t or .Cf eve t v LocatscN ce at t t Ast

, . 9 (b (b,o l I

,9 u PtnSoNNELErrosuaES

• uw es. s ivet or sc eseteoas 3100101 7 =9 is L:J 32 l

la NA g

et nSoNNEt INJu'ests wuw at s ot sc ais t een NA j 8, .40 1 010! ., I, , ,,

o8 858?E CoNstoutNCE5

- NA

]

LoS5 OM oaw GE TO F ACf Lliv t v et CL S C se ** t oo%

W, W L NA y PusteClTv IF! SIA l

r e, ,

AOottsoN AL 8 ACf ons 8I s es NA

~

s. E, . I. j Jacque Lingenfelter/ Rich Chesko (4197 ' 259-5000, Ext. 251 rwoNE ovR o87-t 800127024/3

m --

s DVR 087-1

\

d

• TOLEDO EDISON COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR ?.ER NP-33-77-52 DATE OF EVENT: August 7, 1977 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Loss of speed control of 1-1 Auxiliary Feed Pump Turbine (AFPT).

Conditions Prior to Occurrence: The plant was in Mode 3, with Power (MWT) = 0 and Load (MWE) = 0.

Description of Occurrence: On August 7, 1977 at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br />, while running AFFT l-1, all control room speed control was lost. At this time it was also thought that there was a problem with the governor valve sticking or the governor valve linkage sticking, which caused the AFPT to run at approximately 4000 RFM and approxi=ately 1500 psig pump discharge pressure and the turbine exhaust casing relief valve to lift. Investigation determined that a procedural error in the shutdown of the turbine caused :he turbine to be lined up for this high speed starting condition

, 'N) rather than a mechanical problem. The procedure has been modified. AFFT l-1 was

'- shutdown locally and investigation of the problem coc=enced. When speed control was lost, the Station entered the Action Statement of Technical Specification 3.7.'. 2. The investigation found that both the CW/ AUX and the CCW/ AUX relays were bad as well as a blown control power fuse. As these relays have been a problem before, Toledo Edison and Gaithersburg Engineering Departments were con-tacted for resolution of this problem. Facility Change Request (FCR)77-199 was written, the field change it required was completed and the AFPT l-1 was declared operable at 1905 on August 9, 1977 removing the station from the Action State =ent of Technical Specification 3.7.1.2.

Designation of Apuarent Cause of Occurrence: The failure of the CW/ AUX and CC"/ AUX relays as well as the blown control power fuse were the cause of the loss of speed control. Insufficient current breaking capacity (Design Deficiency) appears to be the cause of the relay failures and the failure of the relays caused the fuse to blow.

Analysis of Occurrence: There was no threat to the health and safety of the public or to station staff. The reactor had not reached initial criticality and there was no decay heat in the reactor core.

Q -

O 6

l

. , - . . . . - , , , , , . . . ~ . .. .,_ - -

-_ . - __ _ -. - .. . ~ - - - - - - - .- - - -

~

l ' Corrective Action: FCR 77-199 c.esolution provides for additional relay contacts 4

to be added in series with the failing contacts to increase the current breaking l

capabilities. With this change completed on Maintenance Work Order MWO 77-165 i on August 8, 1977, the occurrence is not expected to recur.

Failure Data: There were,four previous failures involving the failure of the Auxiliary Feed Pump speed switches, NP-32-77-ll, NP-33-77-39, NP-33-77-53 and NP-33-77-51.

l i

l l

i I

i 9

1 i

..-- -.----v_,- -n,-- .. -,n - - - - _ ---w,_ , - , .nne- x,.~,-