IR 05000335/1979024
| ML17207A551 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 09/27/1979 |
| From: | Dyer J, Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML17207A550 | List: |
| References | |
| 50-335-79-24, NUDOCS 7911090325 | |
| Download: ML17207A551 (5) | |
Text
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UNITEDSTATES NUCLEAR REGULATORYCOMMISSION
REGION II
101 MARIETTAST., N.W., SUITE 3100 ATLANTA,GEORGIA 30303
'eport No. 50-335/79-24 Licensee:
Florida Power and Light Company 9250 Vest Flagler Street Miami, Florida 33101 Facility Name:
St. Lucie Unit No.
Docket No. 50-335 License No. DPR-67 Inspected at St. Iucie Site near Fort Pierce, Florida Inspected by:
. A. Dye Appvove8 by: Z. C.
R. D.
Ma tin, Section Chief, RONS Branch ate igned Date Signed SUMMARY Inspection on September 2-4 and 10-13, 1979 Areas Inspected This routine, unannounced inspection involved 65 inspector-hours onsite in the areas of plant operations and activities during and subsequent to Hurricane David.
Results Of the two areas inspected, no apparent
'items of noncompliance or deviations were identified.
/911 090 3~~
DETAILS 1.
Persons Contacted Licensee Employees-C.
M.
o'J E-J.
H.
C. A.
""K. N.
M. B.
4 ~~~D A
Wethy, Plant Manager Ba Bowers, Maintenance Superintend t
en arrow, Operations Superintendent Wells, Operations Supervisor Vincent Harris, Assistant Manager Power Resource N l s
uc ear
, Assistant Plant Superintendent Electrical Sager, Technical Staff Engineer Other liicensee employees contacted includ d 15 u e operations personnel.
"A dd-Attended exit interview on September 4 and 13, 1979
~Attended ex-Attended exit interview on September
1979
ded exit interview on September 13, 1979 only 2.
. Exit Interview 3.
The inspection scope and findings were summa g
were summarized on September
and wit those persons indicated in Para ra h
grap above.
The po y
o vents that occurrred during av~
uring the exit on S~ptemb~~
S~pt~mbe~
13, 1979.
Due to diesel to start due to loss of the B 4160 volt bus was no prompt reportable occurrence.
The licensee st
'th th NRC o t'o th on e prompt reporting of this occurrence but would i
as suc
.
he inspector acknowledged the licensee's comment.
L'censee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unresolved items were not ident'f d d i x,e uring this inspection.
5.
Events During Hurricane David.
When the inspector arrived on site on Se t Watch" for the St. Luc sx e
on eptember 2, 1979, a "Hurricane ti t d E-Pl I
t P
e
.
ucie plant area had been issued,
'Wth (
emen xng rocedure No. 3100024E.
All ort't 6:00 p.m.
a >>Hurricane Warnings'or the area g
or rea was z.ssued.
The licensee
~
p
"
p
"
g
-2-As a precautionary measure, the licensee made the decision to shut the unit down and go to the cold shutdown condition.
A power reduction was commenced at 6:40 p.m.
on September 2, 1979, and the unit was taken off the line at 9:59 p.m.
The unit was in the cold shutdown condition at 8:59 a.m.
on September 3, 1979.
At approximately noon on September 3,
1979, a cable fromm the Unit no.
stationary Chicago bridge and Iron guyed derrick crane fell across the lines of the "B" Startup Transformer.
A lockout occurred on the East Bus and the
"B" Startup Transformer was lost.
All of the "B" side of the electrical system was de-energized with the exception of the "B" DC bus which was carred by the "B" battery.
The "B" inverter was lost
~ (caused by a blown fuse).
The "AB" AC busses were lost because they were tied to the
"B" side.
The "AB" DC bus which was tied to the "B" DC bus was lost (assumed lost due to current transient).
The station uninterruptable power supply (SUPS)
was lost.
(The normal supply was from the "B" side 480 AC bus and the backup was from the "AB" DC bus).
The SUPS normally supplies annunciator, some instrumentation, lighting, communications (except PAX and Bell),
national alert warning System (NAWAS), and the Sequence of Events Recorder.
The "B" diesel generator failed to start on undervoltage.
The plant was being maintained in cold shutdown by the "B" low 'pressure safety injector (LPSI) pump when the event occurred.
A slight heatup rate was observed.
The licensee started the
"A" LPSI pump and took manual control of flow control valves to maintain system temperature.
Since the reason for the "B" diesel generator not starting on undervoltage was not known and the potential for a faulted bus or ground was suspected, the diesel knife switch (control power)
was opened to prevent the diesel from starting until the busses could be checked by electrical maintenance personnel.
The power to the de-energized busses was restored in a conservative systematic manner.
Busses and load centers were checked to verify that faults or grounds did not exist prior to restoring them to service.
The "B" diesel was placed in service supplying the "B" essential loads and the "A" loads continued to be supplied by the "A" startup transformer.
No items of noncompliance or deviations were identified.
Followup Subsequent to Hurricane David The inspector reviewed and discussed the sequence of events that occurred with operations, electrical maintenance, technical staff personnel and reviewed the Facility Review Group (FRG) draft minutes pertaining to the review of events related to "Hurricane David".
The FRG recommended that, following electrical maintenance checks, it be verified that the
"AB" DC bus could be tied to either the "A" or "B" DC busses and that the "B" diesel would Mart and load automatically on loss of voltage.
The inspector reviewed the:"Control Center Operators Log" for September 5 and 6, 1979, Jp
and verified that these recommended tests were conducted subsequent to repair of the "B" startup transformer and prior to restoring the plant to power.
The cause for not being able to tie the
"AB" DC bus to the "A" DC bus during the event could not be determined.
A check of the diesel start circuitry revealed that a relay in the loss of voltage start start circuit was sticking and hanging up.
The relay was replaced.
No items of noncompliance or deviations were identifie ~J'