ML20151E035
| ML20151E035 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 07/14/1988 |
| From: | Lentine F COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| References | |
| 4925K, NUDOCS 8807250338 | |
| Download: ML20151E035 (3) | |
Text
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Commonwealth Edison 2
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- One First Nabonal Plaza. Chicago, Illinois -
' @V Address Reply to: Poet Omco Box 76,7
'u CNeago, lainois 6061,0 0767 July 14, 1988 Mr. Thomas E. Murley Director of Nuclear Reactor Regulation U.S. Nuclear-Regulatory Commission Mail Station P1-137 Washington, DC 20555
Subject:
Byron Station Unit 2
-Application for Amendment to Facility Operating License NPF-66 Appendix A, Technical Specifications NRC Docket No. 50-45_5 Reference (a):
June 22, 1988 K.A. Ainger letter to T.E. Murley
Dear Mr. Murley:
1 Pursuant to 10 CFR 50.90, reference (a) provided Commonwealth Edison's application for an amendment to Facility Operating Licenses NPF-37 and NPF-66, Appendix A Technical Specifications.
The purpose of this amendment is to revise a
' technical ~ specification action statement concerning the ultimate heat sink.
The particular action statement involves Rock River water level and flow.
Attachment A to reference (a) contains the proposed change to action requirement 3.7.5.e.(2).
Attachment B to reference (a) contains background information regarding the proposed change.
l The purpose of this letter is to request that this amendment be processed under the emergency provisions of 10CFR 50.91a(5) for Facility Operating License NPF-66.
At approximately 1:14a.m. on Thursday, July 14, 1988, Bfron Unit 2 experienced an unexpected shutdown due to the inadvertent opening of the two feeder breakers that connect the Unit Aux and System Aux Transformers to the Unit 2 non-safety related bus, which fo l
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5 resulted in the loos of the 2C feedwater pump.
The unit is currently in Mode 3.
As stated in Attachment B to reference (a),
I the ongoing drought in the mid-western part of the nation has caused 2
the level in the Rock River to drop below the limit specified in the limiting condition for operation of the ultimate heat sink technical
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specification.
That limit is 670.6 feet mean sea level (hSL).
As a result, Byton Station has entered technical specification action 4
requirement 3.7.5.e.
This action requirement permits reactor i
operation to continue for an unlimited period of time as long as river flow remains greater than 700 cubic feet per second (cfs) and
[3 river level remains above 664.7 feet MSL.
Since entering the action requirement, the river level has fluctuated between 670 feet E
- 3 inches and 670 feet - 8 inches and river flow has fluctuated between approximately 1250 cfs and 2100 cfs.
Therefore, substantial PD margin to the technical specification minimum values currently
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exists.
River flow must be verified every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> under these conditions until the level excees 670.6 feet MSL.
W General technical specification 3.0.4 applies to technical E-specification 3.7.5.
According to specification 3.0.4, entry into E;
an operational mode or other specified condition cannot be made g;
unless the conditions of the limiting condition for operation are met without reliance on provisions contained in the action E-l!
requirements.
As a result, Byron Unit 2 cannot startup until the Rock River level exceeds 670.6 feet MSL.
{
E Edison's service territory is expected to see temperatures greater than 900F through at least Monday, July 18, 1988, with ur today's peak load estimated at 15,500 MW.
Other Commonwealth Edison E=
units down in addition to Byron 2 include Zion 1, Crawford 8 and F-Collins 5.
There are also deratings on Dresden, Quad Cities and LaSalle due to river and lake temperature limitations.
As a result, lg Byron Unit 2 is needed to provide power to the service territory and g-needs to be returned to service as soon as possible.
Current plans k
are to return Unit 2 to service at 3:00P.M. on July 14, 1988.
Commonwealth Edison believes that it has taken actions
-p-necessary to try to prevent an emergency situation from occurring.
The proposed Technical Specification amendment was submitted as soon
[
as the potential for such a situation was recognized, and today's unit trip could not have been anticipated.
Processing the Technical Specification change under the emergency provision of 10CFR 50.91(5) ir r
will allow startup to occur with the required river flow being
-F-verified.
This ensures an acceptable level of safety for unlimited continued operation while eliminating an unnecessary restriction on unit startups.
K.
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Please-direct any questions you may have concerning this matter to this office.
Very truly yours, N
F. G. Lentine PWR Licensing Supervisor cc:
Byron Resident Inspector L. N. 01shan - NRR Regional Administrator - RIII 4925K i
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