ML19210A207
| ML19210A207 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/25/1975 |
| From: | Arnold R METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML19210A208 | List: |
| References | |
| GQL-1316, NUDOCS 7910240925 | |
| Download: ML19210A207 (4) | |
Text
.
NRl JSTRIBUTION FOR PART 50 DOC M ATE RI AL (TEMPORARY FORM)
CONTROL NO:
d FILE: INCIDE,7 REronT Fin FROM: Metropolitan Edison Co.
DATE OF DOC DATE REC'D LTR TWX RPT OTHER Reading, Penna.
R.C. Arnold 7-25-75 7-29-75
- C 3 TO:
^"
sac 1 Signed SENT LOCAL POR CLASS UNCLASS PROPINFO INPUT NO CYS REC'D DOCKET NO:
- CCC(
1
'5U-239 DESCRIPTION:
ENCLOSURES:
, o, A/O # 75-24, on 7-15 concerning Failure of a p
Uuclear Services Rever *.7ater Punp Discharge J7
,gk.
Valve........
A l' QP
.c
( Rec'd 1 cy Ltr. )
/
F PLANT N AME:
Three Mile Island #1 y'
FOR ACTION /INFORMATION VCR 7-31-75 BUTLER (L)
SCHWENCER (L) ZIEMANN (L)
REG AN (E)
W/ Copies W/ Copies W/ Copies W/ Copies CLARK (L)
STOLZ (L)
DICKER (E)
/ LEAR (L)
W/ Cocies W/ Copies W/ Cocies
VASSALLO (L)
KNIGHTON (E)
SPELS W/ Copies W/ Copies W/ Copies W/ Copies KNIEL (L)
PURPLE (L)
YOUNGB LOOD (E)
W/ Copies V!/ Copies W/ Copics W/ Copies INTERNAL DISTRIBUTION
'CNG FILEJ TECH REVlEW CENTON LIC ASST A/T IN D.
f.nv ev rt
,.SCHROEDER MRIMES R. DIGGS (L)
B R A I T.'.i A N i
f OGC. RCOM P 50GA #MACCARY GAMMILL H. GE ARIN (L)
SA LTZM AN GOSSICK/ STAFF KNIGHT KASTNER E. GOULBOURNE (L)
MELTZ CASE PAWLICKI BALLARD P. KREUTZER (E) f GIAMBUSSO SHAO SPANG LE R J. LEE (L)
PLANS BOYD
MCDONALD MOORE (L)
- fHOUSTON ENV1 RO S. REED (E)
CHAPMAN DEYOUNG (L)
- ,.NOVAK MULLER M. SERVICE (L)
DUBE (Ltr)
SKOVHOLT (L)
,.ROSS DICKER S. SHEPPARD (L)
E. COUPE GOLLER (L) (Ltr) lPPO LITO KNIG HTON M. SLATER (E)
PETERSON f
P. CO L LINS
."TEDESCO YOUNGBLOOD H. SMITH (L)
HARTFIELD (2)
DENISE J. COLLINS REGAN
/ S. TEETS (L)
KLECKER REG OPR LAIN AS PROJECT LDR G. WILLI AMS (E)
EISENHUT
./Fil E & REGION (2)
BENAROYA V. WILSON (L)
"WIGGINTON p M7F3 (3)
VOLLMER HAR LESS R. INGRAM (L)
F. WILL1/J!$
STEELE M. DUNCAN (E)
- R"?.3U" L'
EXTJRNAL DISTRIBUTIOm f.>
<1 - LOCAL PDR[#+f4'dh MEM
' /
f1 - TIC (ABERNATHY) (1)(2)(10 N ATIONAL LASS 1 - PDR SAN /LA/NY 1 - NSIC (BUCHANAN) 1 - W. PENNINGTON, Rm E 201 GT 1 - BROOKHAVEN NAT LAB f 1 - ASLB 1 - CONSULTANTS 1 - G. U LRIKSON, C RN L 1 - Ne.vton Anderson NEWM ARK /BLUME/AG B ABI AN 1 - AGMED (RUTH GUSSM AN; J -ACRS SE;T TO L;c 1.SST Rm B.127 GT
- SEND ONLY TEN DAY REFORTS *n e> 2
}{ }2h 1-D. RUNKLE'S, Rm E-201
~~'
t/91024 0 f 2$~ f
Wulatory A/Y!= f my E
fM
%C.
1 METROPOLITAN EDISON COMPANY c+ f 7.'
,e s s
's PCST CFF tE 3OX 542 REACING, PENNSYLVANI A 19603 h
' _ LDPHONE 215 - 929 3601 g,po w ac g
s b 25dQ Q % I973 #
I Ju GQ11315 6
..i s.o..
r,.s c.'"
g'
{,'
,,i D
. s c) 1
. r #.I
,I Director Division of Reactor Licensing JULQ9:975 - r U.S. Nuclear Regulatory Commission Q
Washington, D.C.
20555 s
....i
Dear Sir:
?
sT, i
Docket No. 50-289 Operating License No. DPR-50 In accordance with the Technical Specifications for our Three Mile Island Nuclear Station Unit 1 (TMI-1), we are reporting the following abnormal occurrence. Please note that the resistance to ground referred to in our telegram of July 18, 1975, is in error, in that the resistance to ground was not low, rather two of the valve motor phases exhibited high resistance.
(1)
Report Number: A0 50-289/75-24 (2a) Report Date: July 25, 1975 (2b) Occurrence Date: July 16,1975 (3) Facility : Three Mile Island Nuclear Station Unit 1 (4)
Identification of Occurrence:
Title:
Failure of a Nuclear Services River Water Pump Discharge Valve.
Type:
An abnormal occurrence as defined by the Technical Specifications,
paragraph 1.8d, in that failure of a Nuclear Services River Water Pump discharge valve constituted failure of one component of an engineered safety feature that threatened to cause the feature to be incapable of performing its intended function.
(5) Conditions Prior to Occurrence:
} h b
'l--} '
Power : Core: 100%
-)
Elect.: 833 MWe gross OrRD L.wy
. "RC Flow: 138 x 106 lb/hr RC Press. : 2155 psig RC Temp..
579 F PRZR Level:
240 inches PRZR Temp.: 6500F (6) Description of Occurrence:
At 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> on July 16, 1975, while removing Nuclear Services River Water Pump, NR-PIB, f rom service for routine maintenance, its discharge valve, NR-V1B, failed to close when the operator attempted to close it using the remote control pushbutton at the control room co ns ole.
The valve was closed part way using the handwheel on the valve operator. Again the operator attempted to close the valve using the remote pushbuttons and the valve failed to close. Next the discharge valve was manually closed and would not open when the pump (NR-PlB) was started indicating valve motor failure. Investigation revealed that the valve motor had been overheated and two phases exhibited high resistance.
Immediately, NR-Plc and its respective discharge valve, NR-VlC, were verified operable. When the failed motor was found, NR-PlA was selected as the Engineered Safeguards Pump for the A channel. The f ailed motor was replaced and an investigation made into the cause for the failure. The investigation included (1) checking the thermal overload setpoint (2) measuring of the running current with the new motor installed to check for mechanical binding of the valve or operator, and (3) checking of the limit switches to assure that they were operating properly. The valve test was satisfactory and the mo tor running current was acceptable.
(7)
Designation of Apparent Cause of Occurrence:
The apparent cause of this occurrence is material. The motor appears to have experienceu an open phase on one winding, resulting in single phasing of the other two windings. The severe heating of the motor indicated by the melted varnish from the windings, is believed to have resulted from ineffective overload protection. The overload devices were oversized to assure valve travel during an Engineered Safeguards condition and do not provide protection for overload conditions.
The thermal overload device was tested and found to trip in a longer time than required at the test valve. The overload tripped at 50 seconds while the acceptable range is 17 to 38 seconds. The out of specification overload device did not significantly contribute to the motor damage as the overload range (0.92 to 1.00 anps) is significantly above the motor full load current (0.4 5 amps).
The only other descrepancy found with the valve operator or control circuit was a control power fuse not adequately engaged by the fuse 1A76 227
- lip. The poor engagement was found after pulling and checking the c
fuse and may have resulted from bending the fuse clip while pulling the fuse. The poor connection at the fuse is not believed to have contributed to the motor failure.
(8) Analysis of Occurrence:
It has been determined that the failure of NR-VlB did not represent a threat to the health and safety of the public in that:
a.
One Nuclear Services River Water Pump is sufficient to supply emergency cooling water in the event of a loss of coolant accident.
b.
The redundant Engineered Safety (ES) selected pump, NR-Plc and its respective valve NR..ViC were operable.
c.
The valve was failed in its ES position (Failed Safe),
d.
The NR-PlA pump was available for operation if required.
(9) Corrective Actions :
In addition to the immediate corrective actions listed above, long term corrective actions will be taken as follows :
An investigation will be made to attempt to determine the cause for the motor f ailure by vendor or lab inspection of the motor. The thermal overload time setting for the NR-VlA and NR-VlC valves will be teat ed.
The phase resistance and megger readings for the above two
. tors will be checked to assure that they are acceptable.
The Plant Operations Review Committee and Station Superintendent have reviewed and approved the above corrective actions and have taken steps to ensure their completion.
(10) Failure Data:
Reliance Motor No. 447164 - DU Type P Frame K48 3 Phase 850 RPM 60 hz 230/460 volts
.9/.45 amps S tart Torque 2 lb. f t.
Run Torque 0.4 lb. f t.
Similar Occurrences : None Sincerely,
/1 of tlk R. C./ Arnold Vice President RCA:CWS:cas cc: Office of Inspection and Enforcement, Region 1 File:
20.1.1/7.7.3.5.1 1476 c g 9