ML18127A669

LER 1978-011-00 for St. Lucie Unit 1, When Upper Guide Structure Was Removed (Refueling Shutdown), 3 (of 45) Incore Instrument Thimbles Remained in the Core

ML18127A669
Person / Time
Site:	Saint Lucie
Issue date:	04/28/1978
From:	Schmidt A Florida Power & Light Co
To:	O'Reilly J NRC/IE, NRC/RGN-II
References
PRN-LI-78-123 LER 1978-011-00
Download: ML18127A669 (6)

Text

REGULATORY 'INFORMATION DISTRIBUTION SYSTEM <RlDS)

DISTRIBUTION FQR INCOMING MATERIAL 50-335 REC: OREILI Y J P ORG: SCHMIDT A D DOCDATE: 04/ 28/78 NRC FL PWR & LIGHT DATE RCVD: 05/09/78 DQCTYPE: LETTER NOTARIZED: NO COPIES RECEIVED

SUBJECT:

LTR 1 ENCL 1 FORWARDING LICENSEE EVENT REPT <RO 50-335/78-11) ON 04/15/78 CONCERNIhJG 4JHEN UPPER GUIDE STRUCTURE WAS REMOVED (REFUELING SHUTDOWN>, 3 (OF 45> INCQRE INSTRUMENT THIMBLES REMAINDED IN THE CORE... ALL THREE SHOWED EVIDENCE THAT A CLEAN SEPARATION HAD OCCURR8b pF poR~ Pc,nul c'oiho~~

PLANT NAME: ST LUCIE Sl REVIEWER INITIAL: X JM DISTRIBUTOR INITIAL:

~~~~~~~~~~~+4HHI++~~++++ DISTRIBUTION OF THlS MATERIAL IS AS FOLLOWS lNCIDENT REPORTS

< DISTRIBUTION CODF FQR ACTION:

INTERNAL:

BR EG A002)

CHIEF '4 FILE4+W/ENCL ENCL NRC PDR+4W/ENCL

L~ENG MIPC~~4~W/ 3 ENCL SCHROEDER/IPPQI I TO4 ~4J/ ENCL HOUSTON44tW/ ENCL NOVAK/CHECK+4tW/ENCL EEB+4lW/ENCL KNIGHT+<4J/ENCL BUTLER~~4J/ENCL HANAUER+~~W/ENCL TEDESCO+>W/ENCL EISENHUT~~W/ENCL BAER4~W/ENCL SHAO~~~W/ENCL VOLLMER/BUNCH+~>W/ENCL KREGER/ J. COLL INS~~+I J/ENCL ROSA'W/ENCL K SEYFRIT/IE4+WfENCL LPDR S FT PIERCE FL<4~W/ENCL T I C++W/ENCL NSIC+4W/ ENCL ACRS CAT B+%W/16 ENCL COPIES NOT SUBMITTED PER REGULATORY GUIDE 10 ~ 1 DISTRIBUTION: LTR 45 ENCL 45 CONTROL NBR: 78130 09 SIZE: 1P+2P

%% CF%4.%4%%% 8E%+ %%% 4 %% 4F%%%% %%%%%%%%% 0f % THE END

FLOIIIOA POWEII 5 LIGHT COMPANY April 28, 1978 PRN-LI-78-123 Cl 5 ~

P1

~

LO Pl~

urn CV A+cn )'W, R~

Wo~ Vlci CA~

PMMPl Mr. James P. O'Reilly, Director, Region XI Office of Inspection and Enforcement rn ED U. S. Nuclear Regulatory Commission Ch 230 Peachtree Street, N.N., Suite 1217 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

REPORTABLE OCCURRENCE 335-78-11 ST. LUCIE UNIT 1 DATE OF OCCURRENCE: APRIL 15, 1978 TECHNICAL SPECIFXCATION 6.9.1.8.i INCORE INSTRUMENT THIMBLES The attached Licensee Event, Report is being submitted in accordance with Technical Specification 6.9 to provide prompt notification of the subject occurrence.

Very truly yours, D. Schmidt Vice President MAS/mb Attachment cc: Robert Lowenstein, Esquire Director, Office of Inspection and Enforcement (40)

Director, Office of Management Information and Program Control (3)

I 78g300090 PEOPLE... SERVING PEOPLE

4

1

~ .a V p

II t >

l>3 A7

LICENSEE EVENT REPORT e ~.,ie CONTROL BLOCK: SE PAINT ALL AEGUIASD INFORMATION) 1 LCENSEE LCENSE EVENT NAME LCENSE NUMBER TYPE TYPE F I. S L S 1 0 0 0 0 0 0 0 0 4 1 1 1 1 LQQil 89

~

7 14 15 25 26 30 31 32 REPORT PEPORT CATEGORY TYPE SOURCE ~

COCKET NUMBER ~ EVENT DATE REPORT DATE

~01 CQN'T ~X ~L 0 5 0 0 3 3 5 0 4 1 5 7 8 0 4 2 8 7 8 8 57 58 59 60 61 68 69 74 75 60 I

EVENT OFSCRIPTION

%hen the U Der Guide Structure (UGS) was removed (refueling shutdown), 3 (of 45) incore a9 80 instrument thimbles (or scabbards) remained in the core. All three showed evidence that 7 89 80

~4 a clean se aration no loose pieces had occurred before plant cooldown. Each separatio 7 8 9 80 wa. at the oint of attach'ment to the UGS instrument late. These thimbles are not 7 8 9 eo Q~Q Dressure boundaries thev act a "bushings" to su port the incore detectors and to 7 8 9 e0 SYSTEM CAUSE COMPCNENT CODE CQOE CQNIPONENT COOS MANUF~iRER VOLAT1QN

[QD7] ~RA ~B X X X XIX X C 4 9 0 N 7 8 9 10 11 12 17 CAUSE OESCRIPTION Qp e The exact cause is not yet known, but the 3 tubes all separated at a threaded connection .

7 8 9 80 IQQI purther examination and evaluation is planned to aid in determining the exact cause and 7 8 9 80 7 89 the ootential for recurrence. The results of this evaluation will be re orted in a FAC:UTY METHOD OF 80 STATUS POWER OTHER STATUS DISCOVERY DISCOVERY OQQC1 IPT!CN 7

@~71 8

[N I ~00 0 N/A N/A 9 10 12 13 45 46 eo FORM QF ACTIVITY CONTENT RELEASEO OF RELEASE AMOUNT OF ACTSVITY LOCATION QF RELMQSE Hl 7 a 9 LJ LJ 10 11 N/A N/A 60 PERSONNEL EXPOSURES NUMBER 'YP OESCRIPTiON

~OI 0 0 2 N/A 7 8 9 11 12 13 PERSONNEL INJURIES NUMBER 'EECILPTION 7

[ill ~00 8 9 0

11 12 N/A 80 PROB~1,E CONSEGUEiiICES Jim These thimbles are not a oressure boundary.

7 89 80 LOSS OR OAMAGE TO FACILITY TYPE DESCRIPTION pg ~z 7 89 10 N/A PUBLICITY N/A 7 8 9 AODITIONAL FACTORS

~1 8 See page 2 for continuation of Event and Cause Descriptions.

7 89 80 7 89 eo NAME. H. A. Sebo man PLIONE. 305-552-3802 CPO IA'I g NT

s REPORTABLE OCCURRENCE 33S-78-11 LICENSEE EVENT REPORT PAGE TMO EVENT DESCRIPTION continued) prevent detector movement in the fuel assembly CEA guide tubes.

Although evidence showed that the thimbles separated before the plant shutdown, there was no effect on plant operation because the associated detectors were still fully operable and the system is designed with a high degree of redundancy. This item is being reported as a potentially generic problem. This is the first event of its type at St. Lucie. (335-78-11)

CAUSE DESCRIPTION (continued) supplemental Licensee Event Report or in a repair report from the vendor.