ML19262A914
| ML19262A914 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 12/04/1979 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7912110309 | |
| Download: ML19262A914 (2) | |
Text
.4.
O One First National Plaza. Chicago Illinois Commonwealth Edison Address Reply to: Post Office Box 767 Chicago, Illinois 60690 December 4, 1979 Dr. Harold R.
Dentnn, Director Office of Nuclear Reactor Regulation U.S. Nuclaar Regulatory Commission Washington, D.C.
20555
Subject:
Zion Station Units 1 and 2 Control Rod Misalignment Indication NRC Docket Nos. 50-295 and 50-304 Reference (a) :
October 29, 1979 letter from A.
Schwencer to D.
L.
Peoples concerning Control Rod Position Indication Systems (RPI) at Westinghouse PWRs
Dear Dr. Denton:
Reference (a) requested Commonwealth Edison Company to review the Zion Station Technical Specifications to ensure that the control rods are maintained within 112 steps indicated and that rod position indication system is verified to be accurate to within 12 steps.
The results of this review for Zion Station follow.
At Zion Station, the resolution of the Rod Position In, 7 7ation (RPI) System is 15% of span.
Due to this resolution, wher. an indicated misalignment of 12 steps exists, the actual misalignment could be 24 steps.
Therefore, control rod position should be monitored to a t12 step band to account for the RPI resolution.
Zion Station has a Limiting Condition for Operation (LCO) restricting operation with a control rod misalignment of more than 15 inches (21 steps).
A safety analysis cn suc$ a misalignment is reported in Section 14.1.3 of Zion Station's FSAR.
To ensure that this LCO is not violated, Zion Station now monitors control rod position taking into account the RPI resolution.
Control rod position is monitored to a limit of 112 steps from bank demand position.
If control rods are found to be outside of this band, Section 3.2.3.A of the Zion Station Technical Specifications is followed, i.e., within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> either realign the rod or determine by measurement the core peaking factors, or restrict power level to 80% of rated power.
1528 00 7 79 m 10 3 of f
Commonwealth Edison Dr. Harold R. Denton: December 4, 1979 Please address any questions that you might have concerning this matter to this office.
One (1) signed original and thirty-nine (39) ccpies of this letter are provided for your use.
Very truly yours, m
e
'1 D.
L.
Peoples Director of Nuclear Licensing WFN:mae 1528 068