ML20237E382
| ML20237E382 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/18/1987 |
| From: | Shawn Smith TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 0677Q, 677Q, 87-12, NUDOCS 8712280301 | |
| Download: ML20237E382 (3) | |
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' TENNESSEE VALLEY AUTHORITY Sequoyah Nuclear Plant Post Office Box 2000 Soddy-Daisy, Tennessee 37379 December 18, 1987 U. S. Nuclear Regulatory Commission Document Control Dest Washington, DC 20555 Gentlemen:
TENNESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNIT 1 - DOCKET NO.
50-327 - FACILITY OPERATING LICENSE DPR SPECIAL REPORT 87-12 REVISION 1 The enclosed revised special report provides details concerning~ additional information for corrective actions related to meteorological Instrumentation being inoperable for longer than seven days. This event is-reported in accordance with action statement (a) of Limiting Condition for Operation 3.3.3.4.
Very truly yours, 1
TENNESSEE VALLEY AUTHORITY
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S. J. Smith Plant Manager Enclosure cc (Enclosure):
J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323 Records Center Institute of Nuclear Power Operations Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 NRC Inspector, Sequoyah Nuclear Plant l
8712280301 371218 7,k PDR ADOCK 05000327.
PDR '
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An Equal Opportunity Employer
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SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 SPECIAL REPORT 87-12 REVISION 1 DESCRIPTION OF EVENT This special report is revised and submitted to NRC as committed previously to provide additional information for corrective actions related to meteorological instrumentation in the main control room.
l On September 11, 1987, at 1530 EST with unit 1 in mode 5 (0 percent power, l
3 psig, 125 degrees F) and unit 2 in mode 5 (0 percent power, 60 psig, 125 degrees F), the meteorological displays in the main control room were declared inoperable, and Limiting Condition for Operation (LCO) 3.3.3.4 was entered and remained in effect because the meteorological instrumentation was not returned to service. The meteorological data is complied at the meteorological tower located approximately one-half mile southwest of the plant. It is then transmitted to the plant's auxiliary instrument room via telephone lines. Work Requests (WR) B288002 and B288003 were written and the instruments were repaired on September 17, 1987, but since they still were erratic, the instruments were not declared operable. Thus, the meteorological instrumentation has been inoperable for longer than seven days. The action statement for LCO 3.3.3.4 requires a special report to be submitted if meteorological instrumentation is inoperable longer than seven days.
CAUSE OF EVENT The event was ceuted by meteorological data processing system component failure due to unreliable power supply to the meteorological data station.
(Presently, power supply to the station is from Chattanooga Electric Power Board.) Investigation determined that there was no problem with the meteorological tower station equipment. All channels were operable at the meteorological tower station.
l ANALYSIS OF EVENT This special report is being submitted under the requirements of action l
statement (a) of LCO 3.3.3.4 since the' meteorological instrumentation has been inoperable for longer than seven days. The meteorological tower equipment measures wind direction, wind speed, and air temperature, These parameters are needed to determine plume conditions in the event of an unexpected radioactive release to the atmosphere. With both units in mode 5, it is unlikely that an accident would have occurred which would have produced a substantive radioactive release.
Had the plant been in a l
different operating condition, the significance of this event would not have i
changed since the meteorological data could be obtained from the l
meteorological tower station. Also, the meteorological information can be l
obtained from the plant technical support center equipment since the data l
line between meteorological tower and central emergency control center, and plant technical support center was operable.
l
a-CORRECTIVE ACTION A.
Short-Term Corrective Action
- 1. Main control room meteorological instruments have been repaired and-are in service as required by LCO 3.3.3.4.
- 2. Technical Support Center (TSC) equipment has been calibrated and is capable of obtaining meteorological information through Central Emergency Control Center (CECC) and will be used as backup equipment in the event the main control room meteorological instrumentation should become inoperable. The meteorological station. located one half mile southwest of the plant provides meteorological information"
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te both the main control room and TSC through two separate data links.-
B.
Long-Term Corrective Action
minimize the computer outages causes by electrical' power failures.
The.Sequoyah Nuclear Plant (SQN) Environmental Data Station (EDS) is presently on Chattanooga Electric Power Board power which is not considered to be a reliable power source for. computers.
- 2. Replace the existing SQN EDS computers with'a Digital' Equipment Corporation (DEC) Microvax computer.
- 3. Improve the reliability of the process to notify SQN EDS personnel of-meteorological data failure.
The above specified long-term corrective actions.are scheduled to be completed by June 1, 1988.
ADDITIONAL INFORMATION Three Special. Reports have been written on the meteorological Instrumentation being out of service for more than seven days in 1987'-
l 87-03, 87-04, and 87-11.
0677Q r