ML20091H975
| ML20091H975 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/17/1995 |
| From: | Hairston W GEORGIA POWER CO. |
| To: | |
| References | |
| CAL, OLA-3-I-MOSBA24, NUDOCS 9508160347 | |
| Download: ML20091H975 (4) | |
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-t ELV-01516 0012 Docket No. 50-424 U. S. Nuclear Regulatory Comission Region II 101 Marietta Street, N. W.
I Atlanta, GA 30323 ATTN: Mr. S. D. Ebneter
Dear Mr. Ebneter:
V0GTLE ELECTRIC GENERATING PLANT CONFIRMATION OF ACTION LETTER On March 20, 1990, a site area emergency was declared due to a loss of offsite power concurrent with a loss of onsite emergency diesel generator capability.
Following the event, GPC received a Confirmation of Action Letter dated March 23, 1990 concerning certain actions we were taking. We have reviewed the March 20th event and the appropriate corrective actions necessary for entry into Mode 2 have been accomplished.
Therefore, we are requesting approval to return Unit I to Mode 2 and subsequent power operation.
The following discussion provides justification for this request.
In accordance with Vogtle Electric Generating Plant procedures, an event review team has investigated the events leading up to and following the site area emergency. The event review team has presented the results of it's review to management and those recomendations considered important for continued safe plant operation have been implemented. These include establishment of a management policy on control and operation of vehicles (see attached letter from George Bockhold to site personnel); upgrading of emergency notification network comunications (see attached letter from George Bockhold to Emergency Directors and Comunicators);
retesting and calibration of both Unit 1 emergency diesel generator control systems; temporary barricades to prevent unnecessary entry into low voltage switchyard areas; and comunications of imediate corrective actions related to operations to licensed operators.
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In addition, the event review team report also contains a number of longer-term recomendations which require additional management review and evaluation.
These include the sequencing of outage activities; plant conditions during mid-loop operations; post-maintenance diesel functional testing; emergency notification system upgrades; changing diesel generator control logic; and re-evaluating the duties and responsibilities of the Emergency Director.
NUCLEAR REGULATORY COMMISSION Docket No. 50 424/425-OLA 3 EXHIBIT NO,_ b d'D in the rnatter of Geo,nia Power Co et at Voatie Units 1 & 2 t
O Staff O Applicant @ intennnor O Other_
$ Identified O Received O Rejected Reporter _
Cd 9508160347 9505t7 Def 05-QQWitness S+2 w laal P
PDR ADOCK 05000424
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.ExhibitI,page 2,of 1
U.:5. Nuclear Regulatory Commission 4
Region II b
j ELV-01516 i
Pace Two j
f' The most significant occurrence during the event of March 1
failure of Diesel Generator (DG) 1A to remain running to s 20, 1990, involv; cooling. Georgia Power Company i
has investigated the DG failure,and has determined the j
During bench testing, all three jacket water temperature sw a.-
found to be set high during the DG maintenance inspect 1990 (by approximately 6-10 degrees F above the setpoint.
adjusted downward usin that previously used. g a calibration technique that may)have dif 4
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Switch TS 19110 was found to have a setpoin approximately 6 degrees F below its previous setting. grees F which j
as the original setting.found to have a setpoint of 199 d Switch TS 19111
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186 degrees F which was approximately 17 degre
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i setting and was readjusted.
was judged to be. acceptable to support diagnostic reinstalled.
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l During the subsequent test run of the GG on March 30, on c.
(TS 19111) tripped and would not reset.
leaking switchintermittent failure because it subsequently reset.Ti 1
This switch and t !
testing has been(T519112) were replaced with new switches. All s
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conducted with no additional problems.
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the manufacturer's assistance to ensure a i
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Subsequent testing indicated that the diesel annunicator indi e.
March 20, 1990 is reproduced on a high Jacket water temperature trip f.
A test of the jacket water system temperature transient dur starts was conducted.
jacket water temperature at the switch locations w 3
normal standby lineup, and then followed by a series of starts i rolling the engine to replicate the starts of March 20.
that jacket water temperature at the switch location decrease The test showed standby temperature of 163 degrees F to approximately 156 de remained steady.
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GeorgiaPower d U. S. Nuclear Regulatory Comission Region II ELV-01516 i
Pace Three g.
Since March 20, 1990, (including jacket water temperatures, extensive l pneumatic leak testing, and multiple) engine starts a
, special conditions.
Since March 20, the 1A DG has been started 18 time 1B DG has been started 19 times.
No failures or problems have occurred during any of these starts.
In addition, an undervoltage start test without air roll was conducted on April 6,1990 and the iA loaded properly.
Based on the above facts temperature switches were, we have concluded that the jacket water high the most probable cause of both trips on March 2 1990.
a high state of diesel reliability.In addition, the following rtl 1.
understand that an emergency reset will ov 1
temperature trip.
emergency reset functions prior to AprilAlarm response proce 30, 1990.
2.
The undervoltage start feature of the Unit 1 DGs has been the non-essential engine trips are bypassed.
will be implemented on Unit 2 prior to Aprilprovided t (This change 30,1990.)
3.
GPC is evaluating the possibility of a design change and Technic Specification change to delete the jacket water high tempe essential engine trip.
an 4.
GPC has reviewed air quality of the D control and has concluded that air qua/G air system including dewpoint lity is satisfactory.
Initial reports of higher than expected dewpoints were later attributed to faul instrumention.
This was confirmed by internal inspection of one air receiver on April 6,1990, the periodic replacement of the contol air filters last done in March,1990 which showed no indication o daily air receiver blowdowns with no significant water discharg 5.
Based on discussions with the NRC in Atlanta on April 9, 1990 transmit a summary and schedule of the ac
, GPC will NRC by May 15, 1990.
vehicles it. the perimeter area will also be revised by M e
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i N,page1 Of Georgia Power d Exhibit U. S. Nuclear Regulatory Commission Region II ELV-01516 Pace Four 6.
GPC will continue to work with the IIT and an independent lab to evaluate i.
the instruments currently under quarantine. Upon completion of the the lab test, calibration procedures will be revised as necessary to ensure consistent performance.
Completion of these investigations, reviews, tests and corrective actions justify GPC's determination that the DG's are operable. GPC will continue to work with the Transamerica DeLaval Incorporated Owners Group to improve DG.
reliability. GPC will also review possible improvements to protective instrumentation and controls.
Based on the above discussion, we have completed the appropriate corrective actions necessary to safely operate the unit. We request NRC approval to allow Unit I to return to operation.
Should you have any questions, please inquire.
Sincerely, g)..b.!I=
M e
W. G. Hairston, III WGH,III/NJS/gm Attachment xc:
Georaia Power Comoany Mr. C. K. McCoy Mr. G. Bockhold, Jr.
Mr. R. M. Odom Mr. P. D. Rushton NORMS U. S. Nuclear Reculatory Comission Document Control Desk Mr. T. A. Reed, Licensing Project Manager, NRR Mr. R. F. Aiello, Senior Resident Inspector, Vogtle l
92 PRCUECT 057746
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