ML20056A027

Provides Addl Info Re Resolution of Number of Older Licensing Issues,Including Containment Isolation Valve Position Indication,Per NRC

ML20056A027
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	07/30/1990
From:	Chrzanowski R COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9008030097
Download: ML20056A027 (2)

Text

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\\ Commonwealth Edison l

)/ 1400 Opus Place

1. ~

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Downers Cr:ve, Illinois 60516 r

v July 30, 1990 l

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Dr. Thomas E. Hurley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Nathington, DC 20555 Attn. Document Control Desk

Subject:

Zion Station Units 1 and 2 o

Regulatory Guide 1.97 i

NRC_RoILeLBosm50-195 and 50-30A

Reference:

(a) December 8, 1987, letter from P.C. l.e Blond to U.S. NRC.

(b) April 14, 1989, letter from C. Patel to H.E. Bliss.

(c) June 15, 1990, letter from R.F. Dudley to T.J. Kovach.

(d) July 26, 1990, teletonference between CECO and C. Patel.

Dear Dr. Murley:

Reference (b) contained the Safety Evaluation Report for Regulatory Guide 1.97 for Zion Station.

The Safety Evaluation concluded that there was insufficient 4

information regarding containment isolation valve position indication to accept the Communwealth Edison position.

Reference (a) had been submitted to provide the i

necessary information, however, it was not considered in the Safety Evaluation l

Report. Additionally, the Safety Evaluation Report concluded that qualified neutron flux-monitoring instrumentation was required to be installed at Zion Station and requested a schedule for the installation.

Reference (c) requested i

additional information to resolve a number of older licensing issues.

This request included a response to the Regulatory Guide 1.97 Safety Evaluation Report.

This letter provides the requested information.

.Contt1Detallioltt19tLYA1Yt_Eosidon_indicdlon Reference (c) was held on July 26, 1990, between Commonwealth Edison and Mr. C. Patel and other members of your staff regarding the Categorization of l-l containment isolation valve position Indication.

The teleconference concluded with a common understanding that containment isolation valves are Type B Category 1 I

variables for the purpose of monitoring the accomplishment of plant safety functions.

Furthermore, the redundancy requirements and the single failure l

n criteria for Regulatory Guide 1.97 for Category 1 parameters are on a per l

'oS8 penetration basis, and redundancy is not applicable to penetrations utilizing a

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check valvt, or a closed system as an isolation boundary.

Commonwealth Edison understands that environmental, seismic, and safety C grade power supply information will be provided for each containment isolation g

L mo valve position indication.

However, environmental qualification deviations may be 8S acceptable on a case by case basis for containment isolation valves that are gG administratively controlled in the isolated position (locked closed valve).

a.

-85 Zion Station will re-evaluate the requirement to provide redundancy or the basis for only requiring a single valve / position indicator on the Steam Generator Blowdown Sample and Main Steam Isolation Valves.

Dr. Thomas E. Hurley July 30,1990 2

3 s.

Commonwealth Edison is re-evaluating the schedule for the replacement of o

non-environmentally qualifted valve position indication on an "as failed basis" as provided in reference (a).

Based on this re-evaluation and the results of the teleconference, a revised response will be completed and submitted to the NRC by October 31, 1990.

This time schedule is necessary to assure proper review concurrent with other ongoing activities, i

In the December 8, 1987, supplemental response, and during the teleconference, a concern was raised regarding the measuring accuracy of the Zion Ventilation Stack flow Monitors below 20,000 cfm.

The Ventilation Stack flow Monitors will monitor flow over a range of 20,000 to 229,500 cfm with the information avatlable from the plant process computer.

The design range of the i

isokenitic flow monitors is 20,000 to 200,00 cfm.

As such, the flow monitor covers O to 1107, of the isokenitic design flow range.

Zion is currently revising the procedures to ensure that at least 20,000 cfm is provided to the Ventilation Stack Flow Monitors.

A submittal response will be made that will include the results of the review of the containment isolation valves to ensure compliance with Category 1 parameters.

Specifically, Environmental Qualification, seismic, safety grade power supply information, single failure criteria and redundancy requirements will be reviewed.

The schedule for implementation of any modifications or administrative actions will be provided by October 31, 1990.

Meu t rOfLElU LMonllorin9._1 h s t t Unen t Atj On The need to install Category I neutron flux instrumentation has been recognized.

Commonwealth Edison is proceeding with a modification to replace 'he source and intermediate range neutron flux monitoring instrumentation.

The installation of the modifications will begin during the next scheduled Refueling Outages for each Unit.

The Unit I refueling outage is scheduled to begin September 1991, and the Unit 2 refueling outage is scheduled to begin January 1992.

During I

these outages new containment penetrations will be installed that meet the Category l

1 requirements and modification design walkdowns will be completed.

The l

Installation of the new flux instruments will be completed during the next l

refueling outages currently scheduled for the fall of 1992, for Unit 1 and the Spring of 1993, for Unit 2.

These modifications require the installation of a new containment penetration to accommodate cables for the new instruments, installation of additional cabling within the containments and auxiliary building, and installation of the instrument drawers in the main control room.

Due to the scope of the modification, Commonwealth Edison believes that the above schedule accurately reflects the time required to complete the installation of the new l

neutron flux Instruments.

Please direct any questions regarding this matter to this office.

Very truly yours, aMlJ.-

l R. A ChrzanowsNi Nuclear Li insing Administrator 1

cc:

C. Patel - NRR Region III Office Zion Resident Inspector

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