ML20042D366
| ML20042D366 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 11/20/1989 |
| From: | Chrzanowski R COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 9001090055 | |
| Download: ML20042D366 (2) | |
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\\) L C0mmenwealth Edleen '
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Projects and Construction Services i
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g 7 1400 Opus Place, Suite 500 t
(j Downers Grove, Illinois 60515 November 20, 1989 i
Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation i
U.S. Nuclear Regulatory Coassission Washington, DC 20555 l
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Subject:
Byron Station Units 1 and 2 r
Braidwood Station Units 1 and 2 i-DCRDR Implementation NRC Docket Nos. 50-454/455 and 50-456/457 Dear Dr. Murleys i
In the Braidwood Station Safety Evaluation Report Supplement No. 4, the staff concluded that all requirements of Supplement 1 to NUREG-0737 had been satisfactorily completed based on a preimplementation site audit conducted on March 10-11, 1987, except for five items. Two of those items concern the main control board indicating lights. One item regarded the evaluation of the lack of lamp test capability and the second item was the long-terin solution of the apparent indicator light bulb burnout problem.
Commonwealth Edison has evaluated the use of a new indicator bulb using LEDs, similar to those used at Pennsylvania Power and Light's Susquehanna plant. Cosunonwealth Edison's Nuclear Engineering Department
'I looked at numerous LED's over the evaluation period and installed the optimum design into one full panel in the Braidwood Station's main control room. While the LED's were installed, the Braidwood Station Operating Department and the Byron Station Operating Management were i
asked to comment on the suitability of the LEDs.
In addition, the Comunonwealth Edison Human Factors Engineering Group evaluated the LEDs.
The consensus view was that the LEDs focused the light in the upward direction and the position of the equipment was not asertainable from a distance. The operators were most vocal with their objection of the dinener LEDs and recommended that they not be installed in the remainder of the main control room.
Throughout the past year, Conunonwealth Edison has sampled many different LEDs.
In addition to various LED configurations, various lens caps, resistors, voltage combinations, and different sized legend inserts have been evaluated attempting to find a suitable replacement.
The configuration of application of indication lights for the Byron and Braidwood Stations drastically differs from Pennsylvania Power and Light's Susquehanna plant where LEDs have been installed. Conunonwealth Edison believes that a thorough investigation to find a suitable replacement LED has been performed. Based on the configuration at Byron and Braidwood, implementation is not feasible at this time.
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0162Tt57 9001090055 891120 O
PDR ADOCK 05000454
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j Although a suitable replacement LED has not been obtained, in the process of performing our investigation, it was discovered that the j
original high lamp failure and replacement rates at both Byron and Braidwood Stations have drastically declined. The material condition of the stations and the constant manipulation of the controls during the initial construction and preoperational testing stages, increased the failure rate of the incandescent indicating lights in the main control room. Now that the stations are operating, the incandescent bulbs are not being replaced as frequently and the operators have not identified this as a problem.
The Commonwealth Edison stendard for use of indicating lights on the main control board is for one of the two lights to always be lit with the only exception being throttled valves.
For throttled valves, both lights may be lit when the valve is in a throttled or midway position
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between closed and open.
If neither light is illuminated, the operator can assume the worst case of the red bulb being burned out and take appropriate action or immediately inspect for a burned out bulb. This philosophy of operation eliminates the need for installation of bulb test capability because an indicator light should be lit at all times.
In conclusion, Commonwealth Edison believes that the itsue of light bulb replacement rates has been adequately evaluated. The use of LEDs is not a viable option for the Byron and Braidwood Stations. The l
issue of lamp test capability has also been adequately evaluated. The bulb test feature is unnecessary due to the standard main control board design of having one lamp illuminated at all times and due to the extremely large cost associated with the modification of every indication socket in the control rooms.
Please direct any questions regarding this matter to this office.
Very truly yours, I
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l R. A. Chrzanowski Nuclear Licensing Administrator cc Byron Resident Inspector Braidwood Resident Inspector L. N. 01shan - NRR S. P. Sands - NRR Region III Office 0162T l
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