ML20003G015
| ML20003G015 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/10/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-81-405-000 10CFR-050.55E, 10CFR-50.55E, PT21-81-405, PT21-81-405-000, NUDOCS 8104280057 | |
| Download: ML20003G015 (3) | |
Text
_
PART 21 IIErfflRCATION NO, F/ 94 6 o 6
- CEPM dE. I mTE or uma M ETfD. Co - p 8' IMTE DISTRIBlffED ORIGIiML R: PORT]V S!PPLElBS.M' DISTPJBUTION:
PEACTOR (i0i REL CYCLE &
SAFEERRDS (S) g IEFILES
$N O
IE RLES AD/SG AD/FRSI AD/RDI
~
EGIONS I,II,III,IV,V PEGloNS I,II,III,IV,V EGIONS I,II,III,IV,V VB03R BR. R-IV VEiO3R BR. R-IV VBiDDR BR, R-IV i
.LTB / PPA MG 5715 N'SS / FDS SS-395 nag /I)y_
~
EDD NG 7602 LCEB / I'PA 1,1,Q 5715 gES / SG SS-881 kN AEOD NG 7602 LGEB / FPA MG 5715 cdcdT(m mca77.r1 NRR/DSI ASL3? E/W L50 EDD,
MB 7602
~
- N ctfcnunw. mrr6 7tr SAo/SP MG-7210A ASLBP EM 450 -
NRR/D1 CENTIML FILES 016 ENTRAL RLES 016 ASLBP EN 450 CBfiRAL FILES ( GRDN)
CBiiRALFILES (blR0f0 i
CSITRALFILES 016 PDR CEhTRAL FILES SS-395 EhTRAL FILES (CHROFD LPDR PDR PDR TER e
e LPDR
., [k
[p 7
N LPDR
- f. ba,kb s'l 19 e y 4 e M
ACTION:
p PRE.IMItMRY EVALUATION OF THE' ATTACHED FOLLOWJP AS SFUAN BELOW:
' ICATES LEAD RES?0NSIBILITY FOR r
lE IE IOES GIF2.R [
5 "EEs P0.0R ORIGINAL
~~
ezv. sa
i TENNESSEE VALLEY AUTHORITY pgg &
CHnTTnROOGA. TEMNESSEE 374ot 400 Chestnut Street Tower II April 10, 1981 SQRD-50-328/81-19 x
Mr. James P. O'Reilly, Director Office of Ins tion and Enforcement U.S. Nuclear Re latory Commission Region II - Suite 100 101 Marietta Stree Atlanta, Georgia 30 03
Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - GEARED LIMIT SWITCH COVERS MELTING IN ELECTRODYNE MOTOR-OPERATED VALVES - SQRD-50-328/81 FINAL REPORT The subject deficiency was initially reported to NRC-OIE Inspector R. V. Celenjak on February 24, 1981, in accordance with 10 CFR 50.55(e) as NCR's SQN NEB 8112 and 29P. An interim report was submitted on March 25, 1981. Enclosed is our final report. We consider 10 CFR 21 applicable to this deficiency.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2531.
Very truly yours, TENNESSEE VALLEY AUTHORITY l
L. M. Mills, Manager t
Nuclear Regulation and Safety Enclosure Mr. Victor Stello, Director (Enclosure),V/'
cc:
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 i
An Equal Opportunity Eroioyer
I s
w_
ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 GEARED LIMIT SWITCH COVERS MELTING IN ELECTRODYNE MOTOR-OPERATED VALVES SQRD-50-328/81-19 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency Geared limit switch housings in Electrodyne valve motor-operators have been damaged from heat due to the placement of the resistive-type heater in the limit switch compartment. The purpose of the heaters is to prevent moisture from condensing in the compartment. The geared limit switch housings that are damaged from heat separate the limit
~
switch compartment from the gear train. The gears of some motor operators showed evidence of excess heat, but none were found to be inoperable. The affected valves are located in the Component Cooling Water (CCS) and Essential Raw Cooling Water (ERCW) Systems. There are 40 Electrodyne motor operators in the unit 2 portion of the syste'es and 17 in the portion of the systems common to units 1 and 2.
Safety Icplications Damage to the gears of the motor operators due to excess heat could have caused a failure of the limit switch. This failure could have various effects on the motor operator, such as: giving a false position indication to the control room; giving false signals to other equipment if electrically interlocked; and if the motor operator is wired to open against the failed limit switch and was called on to open after failure, the motor operator could be damaged so as to become inoperable. The systems in which the valves are located, the CCS and ERCW, are safety related.
Corrective Action TVA's Division of Nuclear Power (NUC PR) personnel at the Sequoyah l
Nuclear Plant have removed the heaters and inspected the limit switch af..amblies for damage on all of the motor operctors. All but one of the limit switches found to be damaged have been replaced. The l
remaining one will be replaced beEore unit 2 fuel loading.
1 TVA's Division of Engineering D1 sign (EN DES) has contacted the manufacturer of the motor operators and has decided to install smaller, thermostatically controlled heaters to prevent possible l
damage due to condensation within the limit switch compartment over the 40-year plant life. There are presently no heaters in the motor-operators, but operation without the hedters for short periods of time is not detrimental. TVA is presently preparing procurement documents for the replacement heaters and will install them before the end of the first refueling outage for unit 2.
I
,