ML18113A271

LER 1977-005-00 for St. Lucie Unit 1, Two Main Feed Pump Discharge Valves Could Reopen After Closing on a Main Steam Isolation Signal

ML18113A271
Person / Time
Site:	Saint Lucie
Issue date:	02/25/1977
From:	Schmidt A Florida Power & Light Co
To:	Moseley N NRC/IE, NRC/RGN-II
References
PRN-LI-77-43 LER 1977-005-00
Download: ML18113A271 (7)

Text

NRQ FOAM )95 2.76 I a *, U.So NUCLEAR'REGULATOR Y COMMISSION DOCKET NUMBER FILE NUMBER 50 335 NRC DlSTRlCUTION FoR PA 50.DOCKET IVIATERIAL TOI Mr N. C~Xoseley FROM: Florida Power & Light Co. OAT] Oj OQQMENT Miami, Fla, 33101

~ .A D, Schmidt DATE RECEIVED 3 17-77 SLETTER ONOTORIZEO PROP INPUT FORM NUMBER OF COPIES RECEIVED QORIOINAL KUNCLASSIFIED

. SCOPY 1 C.C DEscRIPTIoN Ltr trans the following: (lP) Lic EventReport 77-.5 occurring on 1-25-77 r'e failure of two MFP discharge'.valves due to as-built control cirpuitry did aot meet the'esign intent ' '1P) 'ully (1 cy encl rec'd)

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• E PLANT NAME: Sti Lucie Unit 1

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FOR ACTION/INFORMATION BRANGH CIIIEF:

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W CYS ACRS f CYS 4LOLQKNG S 'NT INTERNAL DISTRIBUTION NRC PDR I'& E (2):

MIPC SCHROEDER/IPPOLITO EIOUSTON NOVAK/CHECK GRIIIES CASE BUTLER HAHAVER TEDESCO/NACCh RY EISENHUT BAER SHAO VOLLIIER/BURGH KREGER/J, COLLINS EXTERNAL DISTR IDUTION CONTRGL NUMBER LPDR0 TIC: +o g'.

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/y FLORIDA PO'vVER 5 LIGHT CQ.'4IPANY February 25, 1977 PRN-LI-77-43 Mr. Norman C. Moseley, Director, Region Il v Office of Inspection and Enforcement gs U.. S.. Nuclear Regulatory Commission,, I 230 Peachtree Street, N.W., Suite 1217

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Atlanta, Georgia 30303

Dear Mr. Moseley:

REPORTABLE OCCURRENCE 335-77-5 ST. LUCIE UNIT,l DATE OF OCCURRENCE: JANUARY 25, 1977.

MS IS CIRCUIT I The attached Licensee Event Report is being submitted in accordance with Technical Specification 6.9 to provide 30-day vnotification of the subject occurrence.

Very truly yours, A.. Schmidt Vice President Power Resources MAS/cmp Attachment CC Robert Lowenstein, Esquire Director, 0=fice of Inspection and Enforcement (30)

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

0 CONTROL GLOCK: (PL 6 PAINT AU. REQUIRED INFORMATION Ul ~ 1 UCENSEE ucENsE EVENT NAME UCENSE NUM8ER TYPE TYPE 01 F L S L S I 0 0 0 0 0 0 0 0 0 4 1 1 1 1

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7 89 14 15 26 30 ~1 32

'75, REPORT REPORT CATEGORY TYPE SOURCE OCCkET NUMEcER ~ EVKan: OATc REPORT CATE I001ICDN7 ~L ~L OI 5 0 Ol 3 3l.5 0 l I 2 5 7 7 "0 2 2 5 7 7 7 8 57 58 59 60 61 68 69 74 GC I

EVENT QESCFIIPTION Qpg Ouring a review of'he Hain Feed Pump'(HFP) control circuitry which had been undertaken I 7 8 9 ,G due to spurious pump trips, it was determined that the two HFP discharge valves could t 7 99 GG

[CC~] reooen c cle after closin on a Hain Steam Isolation Signal (HSIS) under the fol low-7 8 9

~CIE ing conditions: (I)'HFP continues to run, (2) a Safety Injection Actuation Signal 7 9 9 EC 7

~CIG 8 9 I NOT r nt. on reachin full ooen the valves would close 1

if a HSIS were PczfviE Gu SYSTPvl CAUSc CC MPCNENT CChtPCNP4T ~

COOK CQOE COMPONENT COOK MANUFACsiFCR VCLAT1CN

~017 ~BIO ~B Z Z Z Z Z Z z 9 9 9 .N 7 8 9 10 11 12 .17 43 I

CAUSE OESCRIPTION f

~019 The as-buil t control circuitry did not ful ly meet the design intent. On January 25,.

7 8 9 cC

[00!8'977,'after Plant Facility Review Group and Company liuclear Reviewt Board approval, a 7 9 9 EQ

~4,0 control circuit lead was lifted for each valve to ensure that the valves would remain I 7 99 FACUTY e MKTHOO CF STATUS POWER OTHER STATQS OiSCOVERY OISCOVERY CESCRiPTlCN

~8 ~OS O NA .t NA 7 8 9 10 12 13 44 45 46 60 FORM OF

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ACMY CONTcNT RELEASEO OF RELEAS'E ~ AMOUNT OF AC VITY LCCAT1ON CF RELcCZSK i a ~z ~z RR NA 7 8 8 10 11 PERSONNEL EXPOSURES NUMEER TYPE OESCRIPTlON s I, QP ~00 o ~z NA 7 9 9 11 12 13 PERS'ONNEL IN UPIES NUM8cKR CESCRl~iON

~00 0 7 89 11 12 PROBAoLc. CONSEOUEcNCES t115I S i nce these va 1 ves are redundant backups to the Ha in Feed Block Va1ves and ~

s ince a Ha in t 7 8 9 LOSS OR OAMAGF TO FACIUTY TYPE OESCR1PTiCN z NA 7 69 10 PUSUCITy NA 7 89 AGOITIONAL FACTORS Q~ 8 See Page 2 for continuation of Event Description, Cause Description, and Probable 7 8 9

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CG Conse uences.

7 89 GG H. A. Schoppmon PHONc tag

I REPORTABLE OCCURRENCE 335"77"5 LICENSEE EVENT REPORT '

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PAGE TWO

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Event Oescri tion (continued)

I still present. This was the second occurrence of this type. involving a safeguards (ESFAS) design problem (see LER 335-76-3 dated March 18, 1976), however, the first occurrence involved ESFAS response on loss of power, and the two events are not considered to be generically related. (335-77-5) ~

Cause Descri tion (continued) closed when requirec.. This interim fix was determined not to involve

'an unreviewed safety question per 10 CFR 50.59 as it implemented the original design intent of the Final Safety Analysis Report and did not affect any other accident analysis. Final corrective action was co permanently modify the circuits in accordance with ld CFR '50.59 to meet

'the design Intent (335-77-5)

Probable Consequences (continued)

Steam line rupture would most likely initiate SIAS as weil as MSIS, the probability of the valves not remaining closed was low. 4i.

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