05000285/LER-1979-017-03, /03L-0 on 790724:during Normal Operation,D Channel Wide Range Nuclear Instrumentation Failed W/Complete Loss of Power.Caused by Blown Main Power Fuses.Fuses Replaced & Instrumentation Placed in Svc

/03L-0 on 790724:during Normal Operation,D Channel Wide Range Nuclear Instrumentation Failed W/Complete Loss of Power.Caused by Blown Main Power Fuses.Fuses Replaced & Instrumentation Placed in Svc

ML20132A816
Person / Time
Site:	Fort Calhoun
Issue date:	08/06/1979
From:	Kusik L OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20132A814	List: 05000285/LER-1979-017, Forwards LER 79-017/03L-0 05000285/LER-1979-017-03, /03L-0 on 790724:during Normal Operation,D Channel Wide Range Nuclear Instrumentation Failed W/Complete Loss of Power.Caused by Blown Main Power Fuses.Fuses Replaced & Instrumentation Placed in Svc
References
LER-79-017-03L, LER-79-17-3L, NUDOCS 7908210450
Download: ML20132A816 (4)

LER-1979-017, /03L-0 on 790724:during Normal Operation,D Channel Wide Range Nuclear Instrumentation Failed W/Complete Loss of Power.Caused by Blown Main Power Fuses.Fuses Replaced & Instrumentation Placed in Svc

Event date:
Report date:
2851979017R03 - NRC Website

text

___

C747)

LICENSEE EVENT REPORT

{

(

CONTROL BLOCX: l l

l l

l l

lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6

l o l i l I N I E l F l C l S l 1 l@l O l 0 l O ! 0 l 0 l O ! 0 l 0 l 0 l 0 l 0 l@l h l 1 l1 l 1 l 1 lhl l

l@

?

8 9 LICENSEE CODE 14 15 LICEN3E NUMBER 25 26 LICENSE TYPE JO 57 CAT 58 CON'T loill S$RC l L Ql 0 ] 5 l 0 l 0 l 0 l 2 l 8 l 5 l@l 017 l 2 l L l 7 l 9 l@l 018 l o 16 I ? I o l@

7 8

60 61 COCKET NUMBER M

63 EVENT OATE 74 75 REPORT OATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h lo l2l l During nortal power operation, "D" channel vide rance nuclear instrumentation _ failed I 73 ;3; l vith complete loss of power. The system was placed in a 2 out of 3 trip logic l

lo ;4 l l by bypassing "D" channel while the power supply was being troubleshot.

No previous l

event of this nature has occurred at FCS1.

Reference Tech. Spec. 2.15, Table 2-2, l

yo;3; l IO le l l Item 10.

No Technical Specification requirements were violated.

l

[ O l 71 l l

l 10181I 60 7

8 9 OE CODE SUSC E COMPONENT CODE Su8C OE S

E 10191 l II A l@ I E lh l A lh l I I N l S l T l R l U lh [P_jh l Z l h 7

c 9

10 11 12 13 18 19 20 SEQUENTIAL OCCURPENCE REPORT REVISION LER RO EVENT YE AR REPORT NO.

COOE TYPE N O.

@ aE;.g l217I9l l-l l 01 11 71 l/l 10l3l lL l

[,j [0_j 22 23 24 26 27 23 29 30 31 32

~~

K N 'A O

O PL NT MET C NOURS S8 IT FOR1 B.

SUPPLI MAN FACT RER I A l@l Z l@

l Z l@

lZ lh l7 0 l 0l 010 l [1]@

lnl@

lNl@

lXI919l9l@

33 34 35 36 3

40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIC'NS h vava blown I

l 1101 l It was discovered that the nain rever fuses. 2 each Buss VDL l'=_

causing loss of power to the drawer. The fuses were replaced and the drawer i

i1 l2I l placed in service.

No further corrective action is required.

l I

11 131 l I

11 14 1 I 80 7

8 9

• POWER OTHER STATUS OtS RY DISCOVERY DESCRIPTION A S UA l

l A lhl DURING NOR'ML PO'4ER OPNRATION l

l1 l51 dh l 1l 0l 0l@l ACTIVtTY CO TENT EELEASED OP RELEASE AMOUNT OF ACTIVITY LOCATIO'J OF RELEASE NA l'

I NA l

LLLS J l Z l @ l 2 l@l 7

8 9 10 11 44 45 80 PERSONNEL EXPOSURES NUV8ER TYPE

DESCRIPTION

l ITTT1 10 l 0 l 0 l@l Z l@l NA p

~

PERSONNd'iN3u'!iES

' NUMBER

DESCRIPTION

l li l a l 101010 l@l NA 83 7

8 9 11 12 LOSS OP OR OAVAGE TO FACILITY h TYPE OESCRIPTION v

I l i i s I l Z i@l NA 60 7

8 9 10 PUBLICiT NRC USE ONLY L2.Lo]INU@gg3g,,

l "A

I IIIIIIIIIIIIIi

/7-K j A 4 h - 26 h011

-~r-

.it; LER 79-017 Fort Calhoun Station Unit No. 1 Omaha Public Power District Docket No. 05000285 Attachment No. 1

Safety Analysis

The vide range drawer is used only for indication when reactor power is below 10-h and above 15% power. The vide range drawer is used during reactor start-up, between 10-k and 15% power to trip the reactor in the event of a high start up rate. The trip unit for high start up rate is automatically bypassed above 15% power.

Since the plant was operating j

I at 100% power, this trip unit had no effect on the Reactor Protective System.

In the event the reactor vould be required to go below 15%, the other three channels could have been used for indication of nuclear power below 10 h.

- D channel was bypassed as a precautionary measure while troubleshooting that channel. At this time, the Reactor Protective System was placed in two out of three logic.

I b

e

(

(

LER 79-017 Fort Calhoun Station Unit Ho. 1 4

0=aha Public Power District Dgeket No. 05000285 Attachment No. 2

Corrective Action

The Technicians removed all power supplies from the drawer and checked all possible points for a short or other deficiency that might cause a blown fuse. After finding no problem in the power supply draver, the fuses, Buss MDL-l's, were replaced with two new Buss MDL-l's and the unit was placed back in service.

Voltage checks were made on the power supply and after insuring that the power supplies vere operational, the "D" channel was declared operational and the bypass key removed.

The fuse failure was deemed to have been due to old age of the fuse and not due to any actual problem in the power supply itself.

The plant staff consideres this problem a one-time failure of the fuse and contem-plates no further action.

lLB 1

I l

l

[

(-

{

L LER 79-017

- Fort Calhoun Station Unit No. 1 Omaha Public Power District Docket No. 05000285 Failure Data This is the first failure of its kind at Fort Calhoun Station Unit No. 1.

J i

i 9

s,4 4

m.

O 9