ML20137B120
| ML20137B120 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/16/1985 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (55(E)-85-20), (NMP2L-0559), NUDOCS 8601150105 | |
| Download: ML20137B120 (2) | |
Text
-.
.. ~ _
- r M Y NIAGARA R u MOHAWK MNE tmLE POINT--UNIT 2iP.O. BOX 63, LYCOMING, NY 13093/ TELEPHONE (315) 343-2110 December. 16, 1985 (NMP2L 0559) f Mr. R. W. Starostecki, Director i
U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 i
Re: Nine Mile Point - Unit 2 Docket No. 50-410 1
Dear Mr. Starostecki:
Enclosed is -a final report in accordance with 10CFR50.55(e) for the problem concerning pump suction line elevation versu. suppression pool level.
This problem was reported via tel-con to T. Silko if your staff on June 25, 1985, and an interim report was submitted on July 26, 1985.
i Very truly yours, 1
.?
i C. V. Mangan Senior Vice President
\\
CVM/GG/cla (0472P) i Enclosure xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Comission Washington, DC.20555 R.- A. Gram, NRC~ Senior Resident Inspector i
i 10 Ps-PDR I
LSN I
- u..
NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT.- UNIT 2 DOCKET NO. 50-410 f
, Final Report for a Problem Concerning Pump' Suction Line Elevation Versus Suppression Pool Level (55(e) 85-20)
Description of the Problem A review of the suction lines to the reactor core isolation cooling system identified a potential path for. suppression pool water to flow outside of secondary containment to the condensate storage tank located in the CST building.
The reactor - core isolation cooling system nonna11y takes suction from the q
condensate storage tank.
In the event of a low level in the condensate storage' tank, reactor core isolation - cooling main -pump and pressure pump-suction will be switched to the suppression pool.
For this to occur, 2ICS*MDV136 opens to allow flow from the suppression pool and, upon fully
- opening, signals 2ICS*MOV129 to cl ose.-
Valve 2ICS*MOV129 is the only automatic isolation.of the reactor core isolation cooling pump suction line from the condensate storage tank available during changeover to suction from the suppression pool.
Although there are check valves downstream of the condensate storage tank and reactor core isolation cooling prenure ' pump loc.ated upstream of the suppression pool tie-in, an alternate suction line from the suppression pool to the maintenance pump was added as a result of GE AID 57. During a loss-of-coolant-accident, if valve 2ICS*MOV129 were to fail to fully close during changeover to suppression pool suction, there would be a potential flow' path created thrcugh the alternate suction line that could allow suppression pool water to flow through the pressure pump suction line or minimum flow line towards the condensate storage tank, a single failure of a power supply breaker common to 2ICS*MOV129 and 2ICS*MOV136 or other failures could result in both valves failing in the open position.
During a LOCA, the j
pressure above the suppression pool water level is sufficient to cause flow to the condensate storage tank.
This problem is not appli, cable to High Pressure i
Core Spray System.
Analysis of Safety Implications i
The potential flow path described above could result in an uncontrolled release of highly radioactive post-LOCA suppression pool water to the plant l
environment outside of the reactor building.
If ~ this problem had remained uncorrected, it could have adversely affected the safety of operations of the i
pl ant.
Corrective Action Check valve 2ICS*V249 will be added to the reactor core isolation cooling suction.line from the condensate storage tank, down stream of 2ICS*M0V129.
l This check valve will prevent backflow through this'line in the event that
- 2ICS*H0V129 fails to fully close.
l I
This valve is-being added in accordance with Engineering and Design Coordination Report No. 224921.
The valve will be installed by January 15, 1986.
+ -... - -
... ~.---.. - -
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER f6)
Paae f3) p/p/j Sequential
/
/p/
Revision
/
Year p///
Number
///
Number Byron. Unit 1 015101010141514 8 15 1 10 10 0 10 01 2 0F 01 2 TEXT Energy Industry Identification System (EIIS) codes are identified in the text as (xx]
A.
PLANT CONDITIONS PRIOR TO EVENT:
MODE _i__ -
Cold shutdown Rx Power o
RCS [AB] Temperature / Pressure 175'F/ 375 osia 8.
DESCRIPTION OF EVENT:
There was no equipment inoperable et the beginning of this event that contributed to its severity. At 0424 on December 11, 1985. While performing the weekly Locked Fire Door surveillance (0B05 7.11.2.b-1), fire door D-633 was found in the open position by a non-Itcensed Equipment Operator. An electrical cord was found running through the doorway, thereby blocking the fire door in the open position and degrading the function of the fire door as a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> barrier. After the electrical cord was removed. the fire door was verified locked closed. This event did not affect any other systems nor did it require the actuation of any safety systems. Since it could not be determined how long the door remained opened, it must be assumed that the time period exceeded one hour, however, upon discovery, the equipment attendant immediatelyg, returned the door to operable status.
C.
CAUSE OF EVENT:
The electrical cord preventing the fire door from clostrig was traced back to Unit-2 Construction activities. Contractor Construction personnel were using this cord to provide temporary Itghting for their work area and failed to follow the rules set by the " FIRE DOOR KEEP CLOSED" sign.
D.
$AFETY ANALY$I$:
The safety of the plant and personnel was at no time jeopardized since the roan, which is protected by fire door D-633. is also protected by tonization detectors which annunciate in the Control Room. This area contains redundant safety related equipment, therefore, in the event of a fire in this area, a redundant train would still be available.
s E.
CORRECTIVE ACTIONS The electrical cord was removed and the door was verified locked closed by an equipment attendant. The contractor Construction personnel involved in this incident have since attended a retraining session restressing the importtnce of observing fire protection procedures.
F.
PREVIDUS DCCURRENCES:
LER NUMBER TITLE MONE G.
COMP 0NENT FAILURE DATA:
MANUF7CTURER NW1ENCLATURE MODEL NLseER MFG PART NisSER NDNE (0639M)
Commonwealth Edison
'i Byron Nucl:trStation
~
.__ / 4450 North G:rman Church Rord Byron, Illinois 61010 January 6,1986 LTR:
BYRON 86-0021 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555
Dear Sir:
The enclosed Licensee Event Report from Byron Generating Station is being transmitted to you in accordance with the requirements of 10CFR50.73(a)(2)(i) which requires a 30 day written report.
This report is number 85-100-00; Docket No. 50-454.
Very truly yours, d
- t. E. Querio Station Managcr
~
Byron Nuclear Power Station REQ /bf
Enclosure:
Licensee Event Report No. 85-100-00 cc:
J. G. Keppler, NRC Region III Administrator J. Ilinds, NRC Resident Inspector INPO Record Center CECO Distribution List
- 3/017 l
v i
-. _ _ _ _ _