HL-4693, Special Rept 1-94-001:on 940911,seven Days Elapsed Since Main Stack post-accident Effluent Monitoring Sys Declared Inoperable Due to Damage to Sys Electronics by Lightning. Sys Expected to Be Returned to Svc by 940921

Special Rept 1-94-001:on 940911,seven Days Elapsed Since Main Stack post-accident Effluent Monitoring Sys Declared Inoperable Due to Damage to Sys Electronics by Lightning. Sys Expected to Be Returned to Svc by 940921

ML20073C306
Person / Time
Site:	Hatch, Prairie Island
Issue date:	09/15/1994
From:	Beckham J GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-94-001, 1-94-1, HL-4693, NUDOCS 9409230236
Download: ML20073C306 (3)

Text

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Georgia Power Company I

, 40 invemass Center Parkway er Post Offce Box 1295 Birmingham, Nabama 35201 Teleptone 205 877-7279 J. T. Beckham, Jr. Georgia

' Power l Mce President - Nuclear Hatch Project September 15, 1994 # #*'"" " ""*" Wi""'

Docket Nos. 50-321 HL-4693 50-366 l l

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant Special Repon 1-94 001 Main Stack Post Accident Emuent Monitor Inoperable For Greater Than Seven Days Gentlemen:

In accordance with the requirements of the Unit I and Unit 2 Technical Specifications, Georgia Power Company is submitting the enclosed Special Report concerning an event where the main stack post accident emuent monitor was inoperable for greater than seven i days.

Sincerely, e) AA -

J. T. Beckham, Jr. I 1

JKBlet l

Enclosure:

Special Report 1-94-001 cc: Georgia Power Company Mr. H. L. Sumner, Nuclear Plant General Manager NORMS U.S. Nuclear Regulatorv Commission. Washington. D.C.

Mr. K. Jabbour, Licensing Project Manager - Hatch LLS. Nuclear Reentatorv Commission Region H Mr. S. D. Ebneter, Regional Administrator Mr. B. L. Holbrook, Senior Resident inspector - Hatch i[ .

's 9409230236 940915 7i PDR R

ADDCK 05000321 PDR Qu b t

i Enclosure Edwin I. Hatch Nuclear Plant Special Report 1-94-001 Main Stack Post-Accident Efiluent Monitor Inoperable For Greater Than Seven Days A. Requirement For Report This report is required per Unit 2 Technical Specifications Table 3.2-11, Item 16, note g.l.b and Unit 2 Technical specifications Table 3.3.6.4-1, item 13, note b.2.

Specifically, these specifications require that should the Main Stack Post-Accident Efiluent Monitoring System be inoperable for greater than seven days, a Special Report must be issued within 14 days of the event. On 9/11/94 at 1515 EDT. this system had been inoperable for greater than seven days; therefore, this Special Report is required.

B. Unit Status At Time Of Event On 9/11/94 at 1515 EDT, Unit I was in the Run mode at a power level of 2387 CMWT (98 percent rated thermal power) and Unit 2 was in the Run mode at a power level of 2436 CMWT (100 percent rated thermal power).

C. Description Of Event On 9/11/94 at 1515 EDT, seven days had elapsed since the Main Stack Post-Accident Efiluent Monitoring System had been declared inoperable. The system was declared inoperable on 9/04/94 because a lightning strike had rendered its microprocessor controller inoperable. On that day an Instrument and Control technician observed a thunderstorm in the area of the Plant. Following the storm, he checked the system panel for evidence of a lightning strike and found the system unresponsive to keyboard inputs. The system was subsequently reported to Control Room personnel as inoperable. Control Room personnel then entered Limiting Condition for Operation (LCO) 1-94-302 and instructed the Chemistry Department to initiate the preplanned alternate method of assessing post-accident radiation levels as required by the Unit I and Unit 2 Technical Specifications and Plant procedures. The preplanned alternate method requires Chemistry Depar* ment personnel to surveil the normal l

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Enclosure Special Report 1-94-001 range monitor daily provided it is not tripped upscale (which would indicate an abnormal radioactive release). Should the normal range monitor indicate an abnormal radioactive release is underway, the preplanned alternate method requires grab samples of Main Stack effluent to be obtained and analyzed.

Repairs were subsequently initiated per procedure 57SV-D11-018-OS "KAMAN l ACCIDENT RANGE MONITOR FT&C." These repairs involved replacing the damaged system board, central processing unit board, memory board and display card. By 9/12/94, these repairs were largely completed and additional troubleshooting and a calibration of the system was initiated.

D. Cause Of Event The cause of this event was damage to the monitoring system electronics by lightning.

The electronics which were damaged control most aspects of system operation, including both manual and automatic operation of the sample pump and operation of the radiation detection sensors.

E. Corrective Action l As described above, repairs have been undertaken and are largely complete.

Calibration and functional testing of the system is in progress. The system is i expected to be returned to service by 9/21/94, f,

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