ML20090G381
| ML20090G381 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 03/04/1992 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Murley T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20090G388 | List: |
| References | |
| NUDOCS 9203120217 | |
| Download: ML20090G381 (3) | |
Text
o C:mm:nw:alth Edis:n 1400 Opus Pisce Downers Grove, Illincls 60515 Harch 4, 1992 Dr. Thomas E. Murley Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington D.C. 20555
Subject:
Byron Station Units 1 and 2 Braldwcod Station Units I and 2 Notification of Bases Changes to the Technical Specifications N RCloc ke LNosm_50-4541455_and_50-45 GL451
Dear Dr. Murley:
Commonwealth Edison is notifying you of two bases changes to the Byron and Braidwood Station Technical Specifications.
The change to Bases page 3/4 3-3 removes a reference to a Low T (average) signal-in the description of the P-4 Interic,ek functions.
The change to Bases page 3/4 3-4 deletes a reference to magnetic tape as thtr medium for recording-seismic data.
Attachment A provides a description of each change.
Included in Attachment B are the marked up Bases pages for both stations.
Both of these changes are the result of plant modifications which have been evaluated pursuant to 10CFR 50.59, and have been reviewed in accordance with CECO procedures.
Please direct any at- 'lons you may have on this matter to this office.
Very truly yours, giu.
T.H. Simpkin-Nuclear Licensing Administrator Attachment A: Description of Changes Attachment B: Revised Bases Pages cc:
R.H. Pulsifer - NRC A.H. Hsia - NRR S. Dupont - Braidwood, Senior Resident H. Kropp - Byron, Senter Resident B. Clayton - RIII 9203120217 920304 DR ADOCK 0500 4
I ZNLD/1571/9 y
- i
ATTACHMENT A
SUMMARY
OF PROPOSED CHANGES BasetpageJL3/4.3r3:
This bases is being changed to delete the reference.to a Lov T-ave signal in the discussion 06 the actuations at$ociated with the P-4 interlock.
The modification performed affecting this bases involved the removal of the check valves in the feedwater bypass lines to optimize the feedwater flow distribution between the upper and lower nozzles under full power conditions.
This modification also deleted the Low T-ave input to the feedwater Isolation logic, such that a Feedwater Isolation signal is generated with any P-4, or Reactor Trip signal.
The previous configuration generated the feedwater Isolation only if the P-4 signal existed coincident with a Low T-ave signal.
The purpose of removing the Low T-ave input is to ensure a feedwater Isolation on all Reactor Trips.
This would protect the steam generator preheater section from water hanrner due to the introduction of cold Aux 111ary feedwater into the preheater.
With the feedwater bypass line check valves removed, a flowpath from the tempering line to the main feedwater line via the feedwater by] ass Itne was created, absent prompt operator action to manually close t1e bypass line isolation valve.
The modification ensures the preheater will be protected from waterhammer due to cold Auxiliary feedwater flow automatically upon receipt of a Reactor Trip signal.
A simplified diagram of the feedwater arrangement is attached.
l Bases _page.lLJ/L3-4:
This bases change involves the deletion of the words "on magnetic tape" in the discussion of the triaxial accelerometer and time history recorder.
This bases revision is required due a modification recently performed on Braldwood's Seismic Honitoring system.
Byron Scation is considering a similar modification. _Due to reliability problems-encountered with the magnetic tape drives, they have been replaced with solid state memory devices at Braidwood.
The change to a more recent design is expected to significantly improve the overall reliability of the system.
Because only the method of data retention is affected, there is no impact on the ability of the system to detect and annunciate a significant seismic occurrence, and the availability of the data retention features are enhanced.
2NLD/1571/10
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FIG URE 1
ARRAN6EMEf4T OF MAlld AMD[BRAlW BVPASS FEEDeJATER LINES At SYEON