ML19350E756

LER 81-037/01T-0:on 810522,Westinghouse Notified Util of Potential Control & Protection Sys Interaction Concern Re Vol Control Tank Level Instrumentation Control.Caused by Inadequate Design/Safety Analysis Review

ML19350E756
Person / Time
Site:	Farley
Issue date:	06/05/1981
From:	Hairston W ALABAMA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19350E755	List: ML19350E754 ML19350E756
References
LER-81-037-01T, LER-81-37-1T, NUDOCS 8106230497
Download: ML19350E756 (2)

Text

__

'mirat stoCx: I I I- 1 I ~t IQ) (PtEASE I"RINT OR TYPE ALL RIQUIR!D INFORMATIC:D -

l , d- ,

-g ' i t, I J l M 'lF l' 1 l@l~ 0 l 0'-l - l 0 l0 l0 l0 ] 01 -l 0l ~ 0l@l uCENSE NUMga 25

.4 l 1uCEnst 26-l 1 lTyPs 1l1 .50 l@.l37 l car ia lg UCENsIE CCcE 14 15

'*'ly u l L J@l 01 5 l 0 l 0 l 0 l 314 (8 @jsa 015 J 2 l2 l8 [174l@l n li aE= i noar 1 oats

I a 1.sa!@

. Vfs 3 so . si ooCx5TNuusEn sa eve *4ToATE is EVE.;T assCa:

PTION AND PROBABLE CONSEQUENCES h ~

) 2i I Westinehouse notific 1 Alabama Power Conpany that the Westinghouse Water Reactor ' Division's! -

3:2; 1 Safety Revie'; committee has identified a potential. control and protection systa=;i=cer- g a14IIaction concern involving the Volume Control Tank (VCT) level instrumentation control. [

'

• 85!Isystem. This situation represents a violation of the Nuclear Regulatory Co nf usion regu- l 3 is 1.l lations related to separation of protection and control systems and single failure I:ri- g 3 ) 7 l l teria as delineated in GDC-24 and IEEE-279. Engineering review of this notificatica j y,34 y resulted in a determination on May 22, 1981, that this situation is reportable under  ;

so na ~

$YSTEM CAUSE CAUSE COMP. vat.v3 CooE CooE SUSGooE COMPONENT CooE SUSC002 $U3CCof

)ial

&

Ic I JI@ 181@ W@ Iz iz lz Iz Iz I zl@ Iz l@ Iz l@

9 10 II 12 ' 13 18 19 20 SEGOENTIAL OCCURRENCE REPORT REVIS:cN

-

EVENT Yi,AR REPORT No. CooE TYP E. .NC, LEM Ro O17 ,g,Pjg

,

l21 ,8l1l 'l-l l 0l 3l 7l ]/] l0l1l lT l l-I l0I.

- 22 23 24 2s 27 28 29 30 33 02 4 A O. oP T N[

• hours 22 33 i Fda, 3. syPa E UA * ,, gin IG

, @l24Zl@ l Z l @ , lsszl @ l0l0l0l0l lYl@

48 lNl@ l43z l@ l 2 I 9 I 9 I 9 l(-

44 47

-- 3 35 si 40 42 CAUIE CESCRIPTICN AND CORf3ECTIVE ACTIONS 27 ,

,

2 3IiCause for postulated event is inadequate design / safety analysis review. Ticely operator ;

, i,; ] action can negate the postulated scenario and positively address the identified centern. ;

'

g ; 17.'? is equipped with instrument readouts which would indicate the presence .of this ,

,;,,j situation and numerous alarms would be actuated at various times in the event. m pl' ant, iia; } procedures have been changed to ' assure that the operator would be properly alerted to  ;

as Ea

% PCNER oTHER STATUS bt 0 Y otScoVERY CE3CRIPTloN NA l D l@l Notification by Westinghouse j 315 l l G l@ l 0l 0l O'*l@l" "

l

• A$nvliv Cc'OrENT satzesta c? nELEAss toCATio'N or agtsAsE h NAAuouNTor Activity @ l lNA M 4l 3zi h lz l@l 10 tI 44

-

45 30 l

PEM50.NNEL EXPoSUAES NUuSER TYPE oESCRIPT1oM .

i 4 7 l l 010 l 0 l@l z j@l A l

• '

- ' nscNN.l'imu'4Es .

nemen OEsCnsPTsoN0 NA g 3 [ l 0 l 0 l 0 lgl l 2 11 12 SC

,

,: LOS3 07 CR oAMAGE To FACTUTY Q TYPE CEscAt* Tion v 7,4 I zl@l NA

&3 l

44 3 10 PuttictTY .

NRC USE CNtY *

sit t o l l yo@otsCalPTIoM al l NA l'llll;;;;i!} l l 58 88 33 I 4 91 O (j *la ;3 Q q { 4 -

W. G. Hairston, III

[ NAME CF PREPARER

.

'PHoNf205)899-5156 _

_ _ _ _ _ _ _ _ _ . _ _ _ . _ _ . _ . - - . ._ _ . . _ _ _ _ _ _ _ _ . __ _ ___ ___

.

- _ - _ _ _ _ _ _ - - _ _ _ .

. _ _

_

.. y *

.. . ~,," . . <

> 1; w. . r; a , -

-

_

-

LER:81-037/0LT-0

.

~ ' Event Description and Probable Consequences (continued) -

Tathnical' Specification 6.9.1.3.1- (Unit 1) and 6'.9.1.12.1.(Unit 2) . - The postulated

svent is as follows:

Assume the plant-is' operating with a centrifugal charging pump performing *-

~

the . normal charging function.' The failure of the VCT level control syste 6.- (LT-115, or LT-112' fa111ng high) 'causes the . letdown flow to be diverted to -

the Recycle Holdup Tanks. ~The VCT liquid inventory is reduced due to nor=al' charging!without any makeup to the VCT due to letdown. Assuming LT-115 or LT-112 fails high, charging. pump suction is not transferred to the RMST, ~

and without operator intervention th'e VCT could empty causing the centri-fugal charging pump to be damaged due to loss of , suction ' fluid. . The second .;

centrifugal charging pump is then taken to be the assumed active failure.

The RCS inventory decreases.due to normal letdown flow and following let-down isolation, due to RCP seal leakage. However, borated vater -cannot be' injected into the RCS from the centrifugal charging pumps. The operator must find a means to restore the primary inventory lost via letdown and RCP

' seal leakage. In- addition, the operator must be capable of borating the RCS

. Prior to going to a cold shutdown condition.- ,

This scenario assumes that during normal plant operation, one charging purp

'is. running with another on atandby. . Actually, three . charging pu=ps exist,

.although the Technical Specifications require only two.

gr- Following-the failure in the VCT leve] control system, the operator would have approximately 10 minutes-to transfer the charging pump suction from the VCT to th'e RWST, simply stop the pump, or, rest, ore letdown to the VCT.

If no operator action occurs at this time, then'the pump in operation could~

be damaged-due to loss of suction, and th'e plant would continue to lose inventory due to letdown. However, this is a slow loss in water inventory.

Automatic letdown isolation'should occur. Even without letdown isolation or operator intervention, approxicately two days would elapse prior to core J- uncovery. The operator would have considerable time to align the standby pump to the RWST.

The health and safety of the public were not affected by this event.

(Note: This LER is applicable to both Units 1 and 2 of FNP).

Cause ~ Description and Corrective Actions (continued) this situation and would take the appropriate action necessary to assure an adequate water supply to the charging pumps.

,

+

6 w

, , ,

-

- - - , . , -