ML19210A181
| ML19210A181 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/02/1975 |
| From: | Arnold R METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML19210A182 | List: |
| References | |
| GQL-1470, NUDOCS 7910240904 | |
| Download: ML19210A181 (4) | |
Text
.
AEPORT OF /GI;O324AL OCCURRENCE AND/OR It. CIDE!.T NRC DISTRIBUTION FOR PART 50 DOCKET MATERIAL (TEMPORARY FORM) i CONTROL NO:
9427 FILE: INCIDE7r REPonT FI_
FROM: Metropolitan Edison Co.
DATE OF DOC DATE REC'D LTR TWX RPT OTHER Readxing, Pa.
19603 2 c w-ma 9-2-75 9-5-75 XX TOi ORIG CC OTHER SENT AEC PDR XX NRC 1sihned SENT LOCAL PDR vv CLASS UNCLASS PROPINFO INPUT NO CYS REC'D DOCKET NO:
XXX 1
.50-289 DESCRIPTION:
Ltr reporting A0-50-239/75-28' ENCLOSURES:
on 8-23-75 re failure of pressure switch PS-2:
in the control circuit for MS-V-13B....
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_h PLANT NAME:
Three Mile Island Unit 1 FOR ACTION /INFORMATION M MHL 9-6-75 BUTLER (L)
SCHWENCER (L) ZIEMANN (L)
REG AN (ET 3((d
@i g W/ Copies W/ Copies W/ Copics W/ Copics CLARK (L)
STOLZ (L)
DICKER (E)
LEAR (L)
W/ Cooies W/ Cocies W/ Copies W/ Copies PARR (L)
VASSALLO (L)
KNIGHTON (E)
SPELS W/ Copies W/ Copies W/ Copies W/ Copies KNIEL (L)
PURPLE (L)
YOUNGBLOOD (E)
W/ Copics W/ Copics W/ Copics W/ Copics INTERNAL DISTRIBUTION TECH REVIEW DENTON LIC ASST A/T IN D.
C EG V*R e PD pSCHROEDER yGRIMES R. DIGGS (L)
B R AITIIAN
,,,,,OG C, R COM P-506A A1ACCARY GAMMILL H. GEARIN (L)
SALTZMAN GOSSICK/ST AF F KNIGHT K ASTN E R E. GOULSOURNE (L)
M E LT7.
CASE PAWLICKl BALLARD P. KREUTZER (E) f GI AM BUSSO SHAO SPANG LE R J. LEE (L)
PLANS BOYD
MCDONALD MOOR E (L)
- f. HO USTO N ENVIRO S. REED (E)
CHAPMAN
,,NOVAK MULLEH M. SERVICE (L)
DUBE (Ltr)
DEYOUNG (L)
SKOVHOLT (L)
ROSS DICKER S. SHEPPARD (L)
E. COUPE f
GOLLER (L) (Ltr)
IPPOLITO KNIGHTON M. SLATER (E)
PETERSON f
P. CO L LINS
/TEDESCO YOUNG B LOOD H. SMITH (L)
HARTFIELD (2)
DENISE J. CCLLINS REGAN S. TEETS (L)
KLECKER REG OPR LAIN AS PROJECT LDR G. WILLI A\\iS (E)
EISENHUT
/TII E 5,~fiEGION (2)
BENAROYA y WILSON (L)
- WiGGINTON
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VOLLMER HAR LEST W1. ING R AM (L)
F. WILLI /'4S <s STEELE M_. DUNCAN M
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<1 - LOC AL PD R._Jiarrisbut g, Pa.
1 - TIC (ABERN ATHY) (1)(2)(10) - N ATION AL LABS
$N '/1 - PDR SAN /LA/NY f l - NSIC (BUCHAN AN) 1 - W. PENNINGTON, Rm E-201 GT' 1 - BROOKH AVEN NAT LAU f 1 - ASLB 1 - CONSULTANTS 1 - G. ULR t KSON. ORN L 1 - Newton Anderson N EWM AR K/B LUM E/AG B ABI AN 1 - AGMED (RUTH GUSSMAN Rm B-127 GT 6-ACRS SE:72 '20 LIO.*lST R. Ingram 9-6-75 1 - J. D. RUNK S. Rm E 20:
- SEND ONLY TEN DAY REFO.US q
7910240 i
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Z/Mafgra Regulatory Docket Es m.c vi:sa..e ma m was METROPOLITAN EDISON COMPANY r:
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POST OFFICE 3CX 542 REACING PENNSYLVANI A 19603 TELEPHONE 215 - 929-3601 September 2, 1975 GQL 1h70 w,
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- s. ' " t'~. Ig y@(n Director N')..
Division of Reacter Licensing i.,-
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egy
'C U.S. Nuclear Regulatcry Concissien
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a'ashingten, D.C.
20555
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Dear Sir:
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Docket No. 50-289
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i Operating Iicense No. DPR-50 y '.f. ~. _. _ m ;',',
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In accordance with the Technical Specificaticns of our Three Mile I?iaalV, Nuclear Station Unit 1 (TMI-1), we are reporting the fcllowing abnormal occurrence.
(1)
Report Number: A0 50-289/75-28 (2a) Repcrt Date: September 2, 1975 (2b) Occurrence Date: August 23, 1975 (3)
Facility: Three Mile Island Nuclear Station Unit 1 (L)
Identificaticn of Occurrence:
Title:
Failure of pressure switch PS-?2 in the centrol circuit for MS-V-13B.
"'yp e :
An abnor ial occurrence as defined by the Technical Specificaticas, paragraph 1.8d, in that, failure of this pressure switch constituted a failure of a safety feature that threatened to cause the urbine Driven Energency Feed Pu=p to be incapable of performing its intended function.
(5)
Cenditiens Pricr to occurrence:
}k b
Pcver: Core: 1C 0',
Elect.: 831 '4Te (Gross )
% 27 RC Flev: 138 x 106 lb/hr RC Press.: 2155 psis RC Te=p.:
579CF PRZR Level: 235 inches PRZR Temp.: 6h8 F (6)
Description of Occurrence:
Cn August 20, 1975, the Turbine Drive Energency Feed Pump vas run for surveillance testing. The pu=p cperated successfully en steam supplied frcm the " A" Stesn Generator through SS-V-13A.
When FS-V-133 was cpened to test the pump on steam supplied from the "3" Steam Generator, the valve (MS-V-133) veuld not stay in the open position.
When the CPEN pushbutton was released, the valve vculd recicse (the valve should remain cpen until the CLCSE pushbutten is pressed).
This inadvertent reclosure of the valve was identified to be a result of failure of a pressure switch used in the control circuit for LS-V-133 and a pcssible short circuit created by a ground between the 125 VDC bus and the normally cpen contact fcr relay 20x/5SV13E.
It is believed the possible ground creating the short circuit was caused by steam entry into the electrical pcrtion of the pressure switch.
I=nediately, the failed pressure switch was replaced and tLe turbine drive energency feed pump was tested using 33-V-133 within h8 hcurs frc= time of discovery.
(7)
Designation of Apparent Cause of Cccurrence:
The apparent cause for the failure was design in that the pressure switch was exposed to a high ambient temperature. The high te=perature conditions apparently resulted in material detericration and subsecuent steam leakage into the electrical portien of the pressure switch.
The vet, corrcded pressure switch caused a grcund which, as described above, resulted in the centrol relay for the valve becc=ing energized without pressing the CLOSE pushbutten (the relay energizes to c1cse the valve).
(8)
Analysis of Occurrence:
The Turbine Driven Energency Feed Pump was operable frc= the "A" Stesn Generator in that LS-V-13A was cperating correctly. SS-V-13A opens in response to an autc=atic signal unless "A" Steam Generater has a low cutput pressure <100 psi.
If "A" Steam Generater has a lcv pressure, bS-V-133 opens tc start the turbine driven pump provided steam generator outlet pressure is >100 psi.
In additien, the DC =ctor operated valve was available and could have been manually cpened to supply the turbine frc= the "3" Steam Generater. The two half-size =ctor driven emergency feed pumps were operable and available to supply energency feed. Based on the abcve, the pressure switch failure did not threaten the health and safety cf the public.
\\476 \\?b
3.
(9)
Corrective Actions:
In addition to the i==ediate corrective action to replace the faulty pressure switch long ter= corrective actions are to check the similar pressure switch associated with the "A" Stemn Generatcr for stes=
leakage. The presently installed pressure switches vill be evaluated to determine whether a switch with a higher te=perature rating shculd be used. Pending resolutien of the suitability of the present switches, the installed switches vill be visually checked once every 2 weeks for stean leakage.
The Plant Operations Review Cen=ittee and Station Superintendent have reviewed and approved the above corrective actions and have taken steps to assure their ec=pletien.
(10) Failure Data:
Static "O" Ring Pressure Switch 5NN-K5 0 - 1000 psi SP DT Similar Cccurrences: None Sincerely, R. C. Arnold Vice President RCA/CWS/cas File:
20.1.1/7.7.3.5 1 cc: Office of Inspection and Enforcement, Region 1 1476 176