ML20086M367
| ML20086M367 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/10/1991 |
| From: | Shelton D CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1995, NUDOCS 9112170379 | |
| Download: ML20086M367 (2) | |
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- h@'cEnrEmon ENERGY Donald C. Shelton 300 IAdson Avenue Vee President. Nuclear Toledo, OH 436520001 Dads Besse (419)249 2300 Docket Number 50-346 l.icense Number NPF-3 Setial Number 1995 December 10, 1991 United States Nuclear Regulatory Commission Document Control Desk Vashlugton, D. C.
20555
Subject:
Deferral of Seventh Refueling Outage (7RFO) Commitments Gentlement on May 17, 1991, Toledo Edinon submitted a lettet (Serial 1938) which confirmed the status of several moditirations previously committed to be implemented during the seventh tefueling outage (7RFO) of the Davis-desse Nuclear Power Station tini t 1.
The purpose of this letter is to confirm that except as indicated below, these modifications were completed as expected during 7RFO.
The revised schedule for completing the modifications not completed duting 7RF0 is also included.
Technical recommendation TR-149-IAS of the B&VnG Safety and Performance imptovement Ptogram (Sp1P) recommends ensuting that the Instrument Air System components art designed to withstand maximum air flov.
As a result of this recommendation, Toledo Edison decided to replace the existing instrument ait dryer bypass valve with a valve of higher capacity.
As discussed in Serial 1938 Toledo Edison intended to complete this modification during 7RFu, however, higher priority work teplaced this modification in t:e 7CFO outage schedule. Replacement of 8
the insttument air dryer bypass valve can be performed during power opetation and vill be completed by the end ol Cycle 8.
Since this commitment. ras made, many impt ovemen t s to the Station and Insttument Air System have been implemented.
These improvements have enhanced overall system reliability and availability 'htought (1) additional comptessor capacity; (2) improved corrective and preventive maintenance ;irac tices; (3) incteased monitoring and trending of system patameters; and (4) heightened operator avateness through detailed procedures and plant specific simulator training.
Collectively, these imptovements have significantly reduced the 1ikelihood of the postulated loss of instrument air scenario.
Thetefore, replacing the insttument air dtyer bypass valve by the end of Cycle 8 rather than during 7RF0 i
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License Number NPF-3 Serial Number 1995 Page 2 Fuman Engineering Deficiency (HF.D) 1,7.009 vas also intended to be completed during the seventh refueling outage.
On August 1, 1990 (Serial.1820), Toledo Edison provided a schedule for the completion of outstanding HEDs by the erd of 7RFO. The schedule for HED 1.7,009 was subsequently confirmed in Serial 1938.
HED 1.7,009 involves the potential for operator injury by electi tcal shock while replacing the 120 volt bulbs used on the svitchyatd panel. The llED vi11 be resolved through addition of resistors in the indicating light circuitry to lover the voltage of the indicating lights.
During the design process, difficulties arose regarding the demarcation between the onsite and the offsite distribution system.
It was subsequently decided that it would be more appropriate to limit modification to the onsite distribution system. As a result, the modification could not be made during 7RFO.
The required circuit modification to the indicating lights vill be installed during the eighth refueling outage (8RFO).
In the interim, a caution label has been installed on the panel and proper tools are used for bulb replacement. No personnel injuries or plant upsets have occurred as a result of this situation.
Toledo Edison has reviewed the deferral of these two commitments on an individual and collective basis and has concluded that their deferral vill not adversely impact the continued safe operation of the Davis-Besse Nuclear Power Statlan.
Please refer any questions regarding this matter to Mr. Robert V. Schrauder, Hanager - Nuclear Licensing at (419) 321-2366.
Very - t rt,1;ygyours,
MAT /dlm cet A. B. Davis, Regional Administrator, NRC Region III J. B. Hopkins, NRC Senior Project Manager
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V. Levis, DB-1 NRC Senior Resident Inspector-Utility-Radiological Safety Board l
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