ML20055D839

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Provides Supplemental Info in Response to Generic Ltr 88-17, Loss of Dhr. Permanently Installed Level Transmitter, Independent from Refueling Vessel Level Recorder & Led Readout Will Be Utilized
ML20055D839
Person / Time
Site: Zion  File:ZionSolutions icon.png
Issue date: 06/18/1990
From: Chrzanowski R
COMMONWEALTH EDISON CO.
To: Murley T
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
GL-88-17, NUDOCS 9007100075
Download: ML20055D839 (2)


Text

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syi IMe 7N46-2084 June 18, 1990 Dr. Thomas,E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC. 20555 Attn. Document Control Desk

Subject:

Zion Station Units 1 and 2 Generic Letter 88-17 Supplemental Information NRC Docket Nos. 50-295 and 50-304

Reference:

(a) January.31, 1989, letter from R. A. Chrzanowski to T. E. Murley (b) September 15, 1989, letter from R. A. Chrzanowski to T. E. Murley

Dear Dr. Murley:

In reference (a), Commonwealth Edison responded to the programmed enhancemer.ts from Generic Letter 88-17, Loss of Decay Heat Removal.

In that submittal, the first method to monitor the reactor vessel level in the main control room during reduced inventory conditions was discussed.

This method utilizes the Refueling Vessel level Recorder and the LED readout.in the control _ room.

This system has two scales, the first is the wide range used when the, reactor vessel head is removed and the refueling cavity is flooded.

The second is the narrow range used during midloop operations to satisfy the requirements of the Generic Letter.

The recorder, instrument number LR-RC22, shows trends of reactor vessel level in the main control room for use by the operators during reduced inventory operation.

In addition, an LED readout in

.the main' control room allows the operators to know the actual level at a specific period in time.

The narrow range level also has an associated' alarm with the setpoint at 584'6.1", that alerts the operators to take action to increase the reactor vessel level.

In' reference (b), the second method used to monitor the reactor vessel level was presented.

Since that time, Zion. Station and the corporate Nuclear Engineering Department have decided that a permanently installed level transmitter, independent from the Refueling Vessel Level Recorder and LED

. readout described above, will be utilized. This change brings the Zion Station design closer to the design utilized at the Byron and Braidwood Stations.

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The second level transmitter will utilize the same piping leading to

' the existing Lexan sightglass and an independent upper sensing line at the pressurizer.

Thus, the second-level transmitter will be totally independent fromethe first level transmitter.

Therefore, this design that utilizes a second level transmitter with separate upper and lower taps from the first level transmitter satisfies the requirements of two independent level indicators in the main control room during reduced inventory conditions, as specificed in the Generic Letter.

Reference (a) contained the schedule for installation of the hardware modifications.

This schedule informed the Staff that the Zion modifications will be completed following the'1991, refueling outages.

The specific' dates of the refueling outages have changed since reference (a) was submitted. The new dates for the next scheduled refueling outages are as follows:

Unit 1 scheduled to start September 1991 Unit 2 scheduled to start January 1992 Therefore, the second independent level transitter will be installed-at Zion Station by the complettoa of the refueling outages described above.

Please direct any questions regarding this matter to this office.

Very truly yours, h V m<62O}

R. A. Chrzanowski Nuclear Lic nsing Administrator cc:

Zion Resident Inspector C. Patel--'NRR Region III Office