ML19308D367
| ML19308D367 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 06/03/1977 |
| From: | Stewart W FLORIDA POWER CORP. |
| To: | |
| Shared Package | |
| ML19308D360 | List: |
| References | |
| NUDOCS 8002270821 | |
| Download: ML19308D367 (2) | |
Text
O O
SUPPLEMENTARY INFORMATION 1.
Report No:
50-302/77-47 2.
Facility:
Crystal River Unit #3 3.
Report Date:
3 June 1977 4
Occurrence Date:
5-13-77 5.
Identification of occurrence:
Regulating rods Group 7 out of specified limits conertry to Techni-cal Specification 3.1.3.6.
6.
Conditions Prior to Occurrence:
Normal Mode 1 steady state operation.
i 7.
Description of occurrence:
At 1520, regulating rods Group 7 dropped into the core causing the overlap between Groups 6 and 7 to be less than the required overlap of 25%. Power was reduced and Group 7 was relatched. Group 7 was withdrawn and the overlap was manually adjusted to the specified limits in 12 minutes.
8.
Designation of Accarent Cause of Occurrence:
Information from the manuf acturer. indicates that the gate drive relay, as designed, may be the cause of these trips.
9.
Analysis of Occurrence:
At no time during this occurrence was the safety of the g.)neral public affected.
10.
Corrective Action:
Plant Modification 77-5-i8 modifying the gate drive relay, as recom-mended by the manufacturer, was installed and checked out 22 May 1977 and should prevent ratchet trip of the Control Rods.
11.
Failure Data:
This _ was the third occurrence of - this type (Refer. L.ER 77-43).
N g
8002270
-y w
y
,_y-
--m-4
UCENSEE EVENT HEPL T
l eh.m CONTROL OLOCK:l l
l l
l l
l (PLEASE Pn!NT ALL REQUtntD INFCAT.1M;O?J)
(V) a Ao LetNSE ~uM.E.
'O!'
7,'PE"'
( l Fl Ll Cl Rl P l 3 l l0l0l-l0l0l0l0l0l-l0l0l l 4 l 1 l1 l1 l1 l l0l3l 7 09 14 15 25 26 30 31 32
"'rr$ Oo$"CE coCnET NuwoEm EVENT cATE REPOAr cAtt CAttCony EjCON T [ -l -l
'M lt i 10 i s 10 l-In 131012 l 10 i s l i l,17 17 l 10 16 10 13 17 17 I 7 0 b7 bu 59 SO bl 68 09 74 73 uu EVLNT OCGCfl:PTION o
l In Mode 1 operation, Control Rod Group 7 dropp' d into the core causing the overlap l
e 7 09 tiO
@l between Groups 6 and 7 to be less than 2s% contrary to Technical Specification 3.1.3.6. l
~
7 a0 eu 0
l Redundancy N/A. Third occurrence of this tvoe.
Group 7 wAs retrieved and the overlao l 7 09 80
@l adiusted to within the specified limits in the recuired time frame.
I 7 u9 e0 o
l (LER 77-47)
[
7 e9 ga mg SystEu CausE CoWuNtNT CoMPCNENr CODE CODE COMPONENT CCCE
$uPP((A MANufACfufVA VoLArCN
[Rl Bl {
l Cl Rl Dl Rl Vl El lN l lD l 1l 5 l 0l lNl o
7 09 10 11 12 17 43 44 47.
48 f,
CAUCE DESCRIPTION p
@l Probable cause was in design of the gate drive relav configuration.
Relav configura-l 7 89 GO
,[O[0] l tion modified per manufacturer's recommendation.
j
/
'l 9 60 N,/)g g l
- l
\\
gg FaC;ury METHoO oF Status
% power OTHER STATUS DISCOvEAv crSCOVERY DESCAIPTON l El l1l0l0l l
N/A l
lAl l
N/A l
7 0 9
10 12 13 44 45 46 80 ASrv Co4 TENT ACLEASEo OF r.ELEASE l AMOUNT QF ACTMTV LOCATCN OF AELEASE lzl N/A l
l N/A l
3E l zl 7 8 9
10 11 44 45 00 PERSONNEL EXPOSunES
)
NUMBEA TYPE CESCRIPTCH M l0l0[0l Wl N/A l
7 89 11 12 13 GO RERSCNNEL INJunlEC Nuwatn DCSCHaPTON 3E l 01 ol 01 l
N/A l
7 00 11 12 80 OFFSITE CONSEQUENCES DE l N/A l
7 OD 00 LOSS OR OAMAGE TO FACLITY TYPE CESCR:PTON DE LzJ l
n/A 1
7 00 10 LO l
PUBLICITY Ql N/A j
OD OU ADOITIONAL FACTOnS l
See attached Supplementary Information.
7 0g
,, l i.a 8I
__,1 un 7 09 C l{-
MAML.
- 11. P. Stewart
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,_,,,_ niont__Q!1]) 866-4159