ML20058L343
| ML20058L343 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 07/31/1978 |
| From: | Eliason L NORTHERN STATES POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 9105150372 | |
| Download: ML20058L343 (2) | |
Text
I MSD NORTHERN STATES POWER COMPANY t
'lonticello Nuclear Generating Plant Monticello,- Minnesota 55362 July 31, 1978 i
Mr. J. G. Keppler, Director Region III Office of Inspection and Enforcement United States Nuclear Regulatory Co=nission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
MONTICELLO NUCLEAR GENERATING PLWT Docket No. 50-263 License No. DPR-22 f
During review of scram insertion tines on July 28, 1978 following a reactor scra:a, it was detemined that control rod drive 30-47 delayed for approx-imately 1. 4 seconds before scramning. During a subsequent surveillance test CRD 30-47 failed to scra 1.
The scram pilot valves were disassembled and the Buna N disk in the plunger of one of the valves was fotnd broken into several pieces.
Since this was the second such occurrence in the last two c.onths, (see Monticello LER 7S-10), this is cmsidered reportable under Teclnical Specification 6.7.B.1. i (potential generic problem). To eliminate repetition of such an occurrence, the plungers an all :42 scram pilot valves and the two backup scran pilot valves were removed sad replaced i
with new parts.
Six additional broken plungers.;ere found in the scran pilot valves.
The backup scrma pilot valves were found satisfactory.
Preventative Maintenance will be initiated to replace these plungers en a j
t periodic basis.
Yours ve Ly,'
ldusm. &
M L. IC Plant Manager LRE/na:n cc: Director, Office of Management Infomation e
f and Program Control 7g 70096 File Cony sent by teleconier to Kenpler 9105150372 780731 b
CF ADOCK 05000263 E D
i CF lQ T
-~ -
r-(~
(
h Oh f ti f r)T QEGULATORY INFORMATION CISTRIDUTION SYc. TEM (RIDS)
DISTRIDUTION FOR INCOMING MATERI AL 50-263 REC: KEPPLER J G ORG: ELIASON L R DOCDATE: 07/31/7?
NRC
^
N STATEC PWR DATE RCVD: v8/V79 DOCTYPE: LETTER NOTARIZED: NO COPIES RECE1VED SUBJECT.
LTR 1 ENCL 0 FURNISHING LICENSEE EVENT REPT CONCENRING DURING REVIEW OF SCRAM INSERTION TIMES ON 07/23/73, IT WAS DETERMINED THAT COf a ROL ROD DRIVE 30-47 DEL., r EL 30-APPROX
- 1. 4 SECONDS BEFORE SCRAMMING.
PLANT NAME.MONTICELLO REVIEUER INITIAL.
XJM DISTRIBUTOR INITIAL: S L,
-, + % m., -> + + +
- w - DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ********++++**6+++
INCICENT PEPORTG (DISTRIEUTION CODE AOO2)
FDP ACTION:
ER CHIEF OREil? BC HLTR ONLYC4) s 4 cTi ew m re " MV NRC PDR*uLTR ONLYf.1)
INTEpppt; m
I
-+LT~
. ? !L :
HIFCv+LT' ONLi i6 I
c' CYSTEM? ER ++L TR ONLY ( 1 )
CMERGENCY PLAN ER**LTR ONLY(1)
Not /AK ' C! lECK++LTR ONLY ( 1 )
EEB**L' nNLY(1) 40 FOR ENG wLTP ONLY(1)
PLANT SYSTEMS OR**LTR ONLYt1)
HANAUER**LTR ONLY(1)
AD FOR PLANT SYSTEMS +eLTR ONLY(
AD FOR SYS ~ F 'iOJ HLT R ONL Y ( 1 )
REACTOR 'EAFETY PR**LTR ONLY(1)
FNGINEEPTNG EP++LTR ONIY(1)
VOLLPEP/ BUNCH **LTR ONLY(1) 7-_-
_n p.
1 + rn I T ' I E, i Tic D NL y.' ? )
l EXTERI&L.
LPDR'r' MINNEAPOL10, MN HLTR ONLY(1)
TIC, L17 CARTER +r-LTR ONLY(1)
, a._. I t 4LTR JL. 1 ACRS CAT R*LTR ONLY(1.')
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+v+v<-+++<+++v+++++n+++++++<++++e+++
THE END
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