ML20137L076
| ML20137L076 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 01/10/1986 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| 0244C, 244C, Q244C, SL-195, NUDOCS 8601240345 | |
| Download: ML20137L076 (3) | |
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SL-195 0244C January 10, 1986 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555 Attached is a report on the reactor building Southeast ECCS pump room flooding incident which took place at Plant Hatch Unit 1 on December 21, 1985.
This submittal is for information only since the subject event is not reportable per 10 CFR 50.72, 50.73 or the plant Technical Specifications.
Very truly yours, l T hu cr/
L. T. Gucwa CBS/lc Attachment c:
Mr. J. T. Beckham, Jr.
Mr. H. C. Nix, Jr.
NRC-Region II GO-NORMS h00 kbo I
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a Plant Hatch Unit 1 Report on E T S R2np Room Flooding (Page 1 of 2)
On 12/21/85, an Emergency Core Cooling System (ECCS) pamp room was flooded to a level of about 14 feet when an air operated maintenance isolation valve on a Residual Heat Removal (RIR) pamp suction line opened.
When power to the solenoid control valve was removed, as a result of performing a loss of Offsite Power (IOSP)
Test, the maintenance value returned to the open position.
Water flowed from the torus, throagh the opened maintenance isolation valve and into the pany room from a disassembled MIR motor operated pump a2ction valve.
The details of this event are described below.
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'Ite plant was in a refueling mode and all fuel was removed from the l
reacto! vessel.
RIR "A"
loop pump R1ction valve (IEll-F004A) was I
disassunbled for repair af ter failing a local leak rate test (ILRT).
l Maintenance isolation valve (lEll-F065A), which is located between lEll-F004A and the torus, was slut and its control switch was " red tagged" (an administrative control which prohibited switch operation) in the control room.
lEll-F056A is an air operated tutterfly valve which opens on loss of power to its solenoid valve.
At approximately 0054 CST, a relululed Ioss of Offsite Poim test was started per plant procedires.
A "Inss of Coolant ANident" (IOCA) signal was sinulated for diesel generator (D/G)
"M".
That diesel started as reaJired.
Plant personnel then deenergized 4160 volt tus "lE" to sinulate a loss of offsite power.
The D G "lA" altput breaker then inuediately closed altamatically which rernergized tus "lE".
At approximately 0110 GT, D/G "lA" was tripped locally, as recuired by the test procedire, to demonstrate proper D/G logic-function.
During the time that the tus was deenergized power hao tren lost to the control solenoid for 1 Ell-F065A, and that isolation valve opened allowing water to flow from the torus into the southeast ECCS pump room via the disassembled 1 Ell-F004A valve.
Following the plannst deenergization of 4160 volt tus "1E",
dae to the D/G trio, the olant connunication systems were lost.
During this period of time the licensed operators in tha main control room were unable to comnunicate with plant personnel in the D/G tuilding until approximately 0120 CST, at which time, following reset of the trip, the diesel generator aatomatically restarted reenergizing 4160 volt tus "lE".
Following reenergiration of tus "lE", valve lEll-F065A reclosed.
By the time that valve 1 Ell-F065A had reclosed the water level in the southeast DOCS punp room had already ocualized (at a level of 14 feet in that room) with the tonas water level.
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J Plant Hatch Unit 1 Report on ECCS Pu @ Room Flooding (Page 2 of 2)
When power was returned to tus "1E" remiting in page system l
restoration, two calls to the main control room were promptly made j
reporting flooding in the southeast ETS puw room.
A Hi Hi mmp l
level alarm had also been received and the m@ isolation valves had j
automatically isolated.
'Ite isolation signal was then overridden j
marually and the m@ isolation valves were opened to allow the water to drain to the northeast EOCS PJ@ room m@ where it Could be pu@ed i
to radwaste.
After the water level in the southeast ECCS pu@ room l
was mfficiently lowered the source of the flood water was identified.
All of the ecuipment affected by the flooding has been identified and 4
work activities have been schedaled and are now in progress which will restore this eculpment to operability.
The eculpment which was flooded was not recuired to be operable since adecuate redundant systems were available to meet all design and Technical Specification recuirements for the refueling mode of opertation.
In addition, there was no significant release of i
radioactive materials within or cutside of the plant boundaries due to the low activity levels of the toms water which flooded the ECC3 p1mp rooms.
Therefore, there were no plant safety consecuences, nor were the health and safety of the p2blic affected as a remit of this event.
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