ML20114B776
| ML20114B776 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 01/23/1985 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 9662N, NUDOCS 8501290496 | |
| Download: ML20114B776 (2) | |
Text
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N Commonwealth Edison
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) One First Natienti Ptna, Chicago. Illinois O 7 Address Reply to: Post Office Box 767
' s. j Chk.ago. Illinois 60690 January 23, 1985 i
Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Improved Thermal Design Procedures NRC Docket Nos. 50-454/455 and 50-456/457 Reference (a):
August 13, 1984 letter from T. R. Tramm to H. R. Denton.
Dear Mr. Denton:
This letter provides additional information regarding monitoring for feedwater flow venturi fouling at Byron and Braidwood stations.
NRC review of this information is necessary to finalize the full-power Operating License for Byron 1.
In reference (a), Commonwealth Edison indicated that fouling of the feedwater flowmeter venturis would be detected through the trending of secondary plant performance data.
According to Condition C(13) of the present Byron 1 Operating License, a report was to be submitted prior to completing the startup test program.
That report would further document the monitoring program and demonstrate that 0.1% venturi fouling could be detected.
Our review of the available secondary side instrumentation indicates that it is not suitable for the detection of 0.1% venturi fouling.
Any such thermal performance monitoring program would be manpower-intensive with respect to site engineering and instrument maintenance personnel.
It would go considerably beyond normal performance monitoring requirements.
The monitoring program conte:nplated in reference (a) does not presently appear practical.
A' program of venturi inspections is therefore being proposed.
With the present app oach to secondary water chemistry and the exclusion of copper from the secondary system components, venturi fouling is not expected to be a problem at either Byron or Braidwood.
Our operating experience at Zion has demonstrated the success of this approach with regard to the feedwater venturis.
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H. R.-Denton January 23, 1985 ETo. provide additional assurance that venturi fouling is not occurring, at least two of the four feedwater flowmeter venturis on the first unit at each site will be visually inspected at the first
' refueling outage.
Special inspection ports will be installed for this purpose.
If fouling is detected, the rest of the inspection
. ports will be installed and all of the venturis will be cleaned during that outage.
The venturis will be inspected at all subsequent refueling outages.
If no fouling is found during the initial inspection, at least two venturis will be inspected at each subsequent refueling outage.
These inspections will continue until
'it can be demonstrated to the NRC's satisfaction that venturi fouling is-not occurring.
Proper control of water chemistry and this program of routine inspections will assure that the feedwater flowmeter venturis are free of fouling when the precision heat balances for RCS flow determinations are made.
Undetected fouling between inspections can only introduce extra conservatism in reactor thermal operating-limits.
No allowance for undetected venturi fouling will be made in the precision heat balance after each refueling outage.
This is not to say that plant thermal performance will not be trended.
Routine surveillances capabilit MAIN test will account for unit per,formance, y tests, and the annual as well as the derating report made to the Load Dispatcher and other corporate reporting requirements.
Please direct further questions regarding this matter to this office.
One signed original and fifteen copies of this letter are provided for NRC review.
L Very truly yours, fth a fMs" L
T. R. Tramm Nuclear Licensing Administrator j.
Im l-cc:- Byron Resident Inspector 9662N l
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