ML20041F629

LER 81-008/03L-1:on 810813,containment Radiation High Signal 86B Lockout Relay Failed to Actuate When Radiation Monitor RM-062 Placed in Alarm.Caused by Bound Relay Latching Mechanism Due to Dirt & Grease.Latch Cleaned

ML20041F629
Person / Time
Site:	Fort Calhoun
Issue date:	08/27/1981
From:	Mueller R OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20041F628	List: ML20041F627 ML20041F629
References
LER-81-008-03L, LER-81-8-3L, NUDOCS 8203170238
Download: ML20041F629 (4)

Text

NRC FORM 33G U. S. NUCLEAR RECULATORY COMMISSION (7 77) .

/ - LICENSEE EVENT REPORT CONTROL OLOCK: l i

l l l l l lh o

(PLEASE FRINT OR TYPE ALL REQUIRED INFORMATION) lo ll l4 l_N 1 9 I EL6CENRE l F l CODE C l S I 141 l@l IS 0 l 0 l 0 l 0 LICENSE l 0 l 0NUMBEH l 0 l 0 l 0 l 0 ! 0h l@l26 4 l 1 l 1 l 1 l 1 l@l$7 CAT LICENSE TYPE JG l

68 l@

CON T lolil i 3 1RM l L l@l ol 5101010l2l815]@l0l8111318111@l0l812l7l8l1l@

60 68 DOCKET NUMBER tA 69 EVENT DATE 74 75 R EPOR T D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l o lil LH1;b the reactor operatinn at approx. 95% oower. engineered safeguards eauinment re- I l o 131 l lating to RM-062 was tested for proper operation prior to a nas release. Subseauentlyl l o 141 l the 86B/CRilS (Containment Radiation High Signal) lockout relay failed to actuate when__j loi3J lRM-062 was placed in " alarm". This also resulted in a failure of the derived signal l l a ls l j lockout 86Bl/CRHS relay to actuate. The redundant channels relay, 86A/CRHS and 86Al/ l

[ o l 7 l [ CRHS were operable and did actuate at the time of the 86B/CRHS failure. I 10181 l 80 l

7 8 9 C DE CODE S BC E COMPONENT CODE SUBC dE SU E 10191 l SI Hl@ Wh W@ l Rl El Ll Al Yl X]@ W@ [Z_j @

9 10 12 13 19 20 7 8 11 18 SEQUENTIAL OCCURRENCE REPORT REVISION

,,,, EVENT YE AR REPORT NO. CODE TYPE NO.

@ r"LE u'['h"dR:RO

_ 21 I 8! II JJ

{J 23 l 0 10 18 l 24 16 M

21 l 013 l 78 29

[L_j 30 l-l 31 l ll 32 A ErJ A 70 ON PL NT TETH HOURS S8 IT O FO tb d. SUPPLIE MANUFACTURER I33B l@Lx_J@ 34 LZ_l@

33 Lz_J@

36 10 10 10 10 I 31 40 L.21@

41 W@

42 lA_J@

43 l44Cl OI 8I Ol@47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l1 l o l I The relay . latching mechaninm t.ms fnund en ho hnuna dun en dive /gronco_ m ~il l li [i l l latching mechanism was cleaned and lubricated. Subsequently, the relay was tested J i,,,j l several times and proved to be operating satisfactorily in all cases. I I i i :t l l l l i l 41 1 I I 8 9 80 ST 5 *

.PCWER OTHE R STATUS ISCOV RY DISCOVERY DESCRIPTION 11 IS I l E l@ l0 l9 l5 ]@l NA l U @l Pre-purge testing l A TtVITY CO TENT nEtrAStO OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE I1IG{[Zj @ (ZJQl 1 E 9 10 _ 11 NA 44 l l 45 NA 80 l

PERSONNEL FXPOSURES NUMlER TYFE DESCRIPTION NA LLLLI I I 010J@l Z l@l l PERSONNE L INJU IES NuYRER D ESCRIP TION

[,jjl0l0l0l@j A l 7 8 9 11 11 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION LLLJlZl@l NA 8

l

' 8203170238 820305 NRC USE ONLY PDR ADOCK 05000285 ,

1 2 o 8 3 issuel @DEsCniPTiON@

10 NA S PDR l 68 69 lllllll;;;llly 80 5 NAME OF PREPARER PHONE:

a l

LER 81-008 Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 ATTACHMENT NO. 1 Safety Analysis The Fort Calhoun Station Unit No. 1 Engineered Safeguard Features are designed such that no single failure can prevent Engineered Safe-guard equipment from performing designed safety functions. During the time of the failure of the 86B/CRHS lockout relay, the redundant channel 86A/CRHS lockout relay (and its associated derive.d signal relay, 86Al/CHRS) was operable and fully capable of performing the necessary functions to safely mitigate an accident.

The 86A/CRHS and 86B/CRHS lockout relays are tested each month per Surveillance Test ST-RM-2 and prior to all containment gas releases.

Since these relays are tested on a regular basis, with few resultant relay failures, further maintenance and/or testing of these relays is not warranted at this time.

L

LER 81-008 Omaha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 ATTACHMENT NO. 2 Corrective Action Upon testing the Radiation Monitor RM-062 "high alarm trip" and the corresponding 86B/CRHS lockout relay, the relay failed to trip properly.

The operators immediately placed_the Ventilation Isolation Actuation System (VIAS) actuation circuitry into its accident position. M.O.

1. 11182 was written to investigate the problem. Corrective action in-volved the cleaning and lubricating of the rollers and brass bushings of the 86B/CRHS coil trip mechanism. The relay was then retested several

- times and operated satisfactorily each time.

. . . e ;

LER 81-008 Omaha Public Power District Fort Calhoun Station Unit No.1 Docket No. 05000285 ATTACHMENT NO. 3 Failure Data This is the fourth failure involving'CRHS lockout relays at Fort Calhoun Station Unit No.1. The remaining failures referenced as per LER's79-022, 78-004, and 77-026.

I t

1