ML18113A263

LER 1976-040-00 for St. Lucie Unit 1, Shutdown Cooling Flow - Update Report No. 1

ML18113A263
Person / Time
Site:	Saint Lucie
Issue date:	03/04/1977
From:	Schmidt A Florida Power & Light Co
To:	Moseley N NRC/IE, NRC/RGN-II
References
PRN-LI-77-58 LER 1976-040-00
Download: ML18113A263 (6)

Text

NRC FOAM 195 U.S, NUCLEAR REGUI.ATORV COMMISSION DOCKET NUMBF R I2.76)

FILE NUMSER NRC DISTRIBUTION FQR PART 50 DOCKET MATERIAL INCIDENT REPORT TO: FROM: DATE OF DOCUMENT

~ DATE RECEIVED 0LETTER 0 NOTO R IZ E D PROP INPUT FORM NUMBER OF COPIES RECEIVED 0OR IGINAL 0 UN C LASS IF E D I

0COPV DESCRIPTION ENCLOSURE PLANT NAME; NOTE: IF PERSONNEL EXPOSURE IS INVOLVED SEND DIRECTLY TO KREGER/Jo COLLINS FOR ACTION/INFORMATION BRANCH CHIEF:

M 3 CXS FOR ACTION

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'CRS CYS QQLQXHG S 'NT INTERNAL DISTRIBUTION REG FILE I 6r. E (2 MIPC SCHROEDER/IPPOLITO HOUSTON NOVAK/CHECK GRIMES CASE BUTLER

'HANAUER TEDFSCO/HACCARY EISENHUT BAER SHAO VOLL?KR/BUNCH KREGER/Jo COLLINS EXTERNAL DISTRIBUTION CONTROL NUMBER LPDR:

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NAC FOAM 196 (2.76)

U.S, NUCLEAR RFGULATORV COMMISSION DOCKET NUMOEII,;

Nf+i PCiRM (2.'e6) r 195 NRC DISTRIBuTION FoR PART 50 DOCKET MATERIAL 0 FILE NUMBER

'0-335 To: Mr. Norman,C Moseley FROM: Florida Power & Light Co, DATE OF DOCUMENT Miami, Fla. 33101 3-4-77 A,D, Schmidt DATE RECEIVED 3-17 77 I3LETTER ONOTORIZED PROP INPUT FORM NUMBER OF COPIES RECEIVED O ORIGINAL EUNCLASSIFIED IRCOP V 1 Lt;r trans the following: . (1P) Lic Event Report addi info dealing with 076<<40 involving cooling relief valves:

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(1 cy encl tec'(I ACKNOWf ZDGFD PLANT NAME- St Lucie Unit 1 SAFETY FOR ACTION/INFORMATION ASSIGNED AD:

R~OC IANA E PROJECT MANAGER IC ASST LIC ASST INTERNAL 0 IST RI BUTION REG FILE SYSTEMS SAFETY PLANT SYSTEMS SI SAFE NRC .PDR HEINEMAN TEDESCO 4'. X-~E .. CCHROEDER OELD GOSSICK & STAFF ENGINEERING IPPOLITO MIPC ERNST CASE BOSHAK BALLARD SIfREIL OPERATING REACTORS YOUNGBLOOD HARLESS PAMLICK STELLO SITE TECH MANAGEMENT

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~ 7 FLORIDA POWER 8 LIGHT COMPANY March 4, 1977 PRN-LI-77-58 Deef(et 5<.

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~+PI Mr. Norman C. Mosel'ey, Director, Region Office of Inspection and Enforcement.

II U. S. Nuclear Regulatory Commission 230 Peachtree Street, N. W., Suite 818 Atlanta,, Georgia 30303

Dear Mr. Moseley:

REPORTABLE OCCURRENCE 335-76-40 ST. LUCIE UNIT 1 DATE OF OCCURRENCE: JULY 18, 1976 SHUTDONN COOLING FLON UPDATE REPORT NO. 1 The attached Licensee Event Report is being submitted to update our initial report of August 18, 1976.

Very truly yours, c

A. D. Schmidt Z+

Vice President Power Resources MAS/cmp Attachment cc: Robert Lowenstein, Esquire Director, Office of Inspection. and Enforcement (30)

Director, Of fice of Management Information and Program Control (3) 59OlyO 504 PEOPLE... SERVING PEOPLE

~ e LICENSEE EVENT REPORT, initial Report 1 CI August 18, 1976 CONTROL BLOCK: I UPDATE 5 1 EBB PRINT ALL REQUIRED INFQRMATIDN)

IJCENSEE LCENSE EVENT NAME IJCENSE NUMSER TYPE F L S L S 1 . laLaJ

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7 89 14 15 25 26 REPORT, FIEPQRT Supplementary CATEGORY. TYPE SOURCE COCKET NUMSER EVEN% OATS REPORT CATE'

[oa~joom 0 7 1 8 7 3 0 4 7 7 7 8 57 58 59 60 61 68 69 74 75 80 EVENT DESCRIPTION

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z 89 During reactor shutdown and cooldown, it was found that ressurizer 80 level would drop whenever either set of shutdown coolin s stem suction 7 8 9 ED

~0 4 valves were o ened. Pressurizer level dro ed because there was flow 7 8 9 60 tQQI throu h both the "A"'nd "B" suction lief 1 7 8 9 7

Qo I8 9 tain ressurizer level it was PRME necessa to st 60 60 SYSTEM CAUSE COMPONENT CQMPCNPIT COOE COOE COMPONENT COOE SUPPUER MANUFACIL E'ER

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~E v Ia 10 11 12 17 48 CAUSE DESCRIPTION tgg~j The above occurrence was caused by the shutdown cooling relief valves 7 8 9 60 (999I 7 8 9 opening helow the design setpoint. pressure and then failin to reseat

~10 in their intended manner. An evaluation was erformed and the 7 8 9 80 FAClIJIY METHQO OF STATUS 'C POWER OTHER STATUS OISCOVERY OieCOVERY OESCRPTION Qg ~o ~oo o N/A N/A 7 8 9 10 12 13 44 45 46 FORM QF ACTIVffY CONTENT RELEASEO QF RELEASE AMOUNT QF ACTiillTY LOCATION QF RELEASE .

7 QH 9

Lil 9

LiJ 10 11 N A N A PERSONNEL EXPOSURES 7

EG3 8 9 La&LlLI 11 L2J 12 13 PERSONNEL INJURIES 7

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~oo NUMBER 11 12 CEECRIPTION N A PROBABLE CQNSEGUENCES t115l N/A 7 8 9 60 LOSS OR DAMAGE TO FACIUTY TYPE OESCRIPTIQN N/A 7 8 9 'IO 80 PUBLICITY Q7 N A 7 8 9 ADDITIONAL FACTORS CG 1 6 See Pa e Two for cantinuation of Event Descri tion and Cause Descri tionJ 7 8 9 60 7 89 M. A. Scho man

Reportable Occurrence 335-76-40 Licensee Event Report Update 51 Pa e Two EVENT DESCRIPTION (Continued) down cooling flow on a cycle of approximately fifteen (15) minutes. RCS pressure was reduced and maintained below 210 psia and both relief valves were gagged shut to allow con-tinuous operation of the shutdown cooling system. The shutdown cooling relief valves were not seating properly which caused pressurizer level to drop whenever the suction valves were opened. (335-76-40). E CAUSE DESCRIPTION (Continued) following recommendations made:

(1) Reposition the relief valves such that the valve stem/disc assemblies are in the vertical plane. This will insure that the disc insert is not allowed to rotate.

(2) Reset. the blowdown of each of the valves from the present 25% value to approximately 10%. This will minimize the effect on pressurizer level while still'rotecting the shut-down cooling piping.

(3) Increase inlet piping size to provide direct and unobstructed flow to the relief valves. This will prevent valve oscilla-tions due to flow choking.

The above changes do not alter the design intent. or function of the relief valves, and were approved for plant modification under the provisions of 10 CFR 50.59.

The modification has been completed and on a subsequent startup from cold shutdown no problems were observed.