TXX-4479, Application to Amend CPPR-126 & CPPR-127,changing Tech Specs to Replace Automatic MSIV Bypass Valve Actuators W/Manual Operators.Changes Will Be Incorporated in Future FSAR Amend

Application to Amend CPPR-126 & CPPR-127,changing Tech Specs to Replace Automatic MSIV Bypass Valve Actuators W/Manual Operators.Changes Will Be Incorporated in Future FSAR Amend

ML20128C479
Person / Time
Site:	Comanche Peak
Issue date:	05/17/1985
From:	Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Noonan V NRC - COMANCHE PEAK PROJECT (TECHNICAL REVIEW TEAM)
Shared Package
ML20128C482	List: ML20128C525 TXX-4479, Application to Amend CPPR-126 & CPPR-127,changing Tech Specs to Replace Automatic MSIV Bypass Valve Actuators W/Manual Operators.Changes Will Be Incorporated in Future FSAR Amend
References
TXX-4479, NUDOCS 8505280304
Download: ML20128C479 (2)

Text

r 7 i I Log # TXX-4479 TEXAS UTILITIES GENERATING COMPANY Fi1e # 10010 MKYWAY TOWER

• 400 NORTH OLIVE NTHEET. L.B. M1

• DALLAM.TEXAM 73201

• May 17, 1985

'L""Z.0?5*

Director of Nuclear Reactor Regulation Attention: Mr. Vincent S. Noonan, Director Comanche Peak Project Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 REQUEST FOR CHANGE TO CPSES TECHNICAL SPECIFICATIONS CONCERNING REPLACEMENT OF MSIV-BYPASS VALVE ACTUATORS

Dear Mr. Noonan:

The Main Steam Isolation Valves (MSIV) at CPSES are equipped with four-inch bypass valves. The bypass valves are used to warm up the steam piping and equalize the pressure across the MSIV's during plant startup.

The bypass valve hydraulic actuators currently installed at the p bit have required extensive maintenance and repair work for reliable opsration.

TUGC0 proposes to replace the automatic (hydraulic) actuators with manual operators in order to eliminate the potential for problems during plant operation.

General Design Criterion 57, " Closed System Isolation Valves," permits the use of locked closed manual valves for containment isolation. The CPSES Technical Specifications currently require containment integrity during Operational ~ Modes 1, 2, 3, and 4. However, the operation of the MSIV bypass valves is required during Modes 2, 3, 4 (Startup, Hot Standby, and Hot Snutdown). TUGC0 has determined that manual operation of these valves during Modes 2, 3 and 4 will not significantly increase the potential for radioactive releases for postulated accidents requiring containment isolation. This is cased on:

1. Lack of credible accident scenarios requiring containment isolation where MSIV bypass valves could significaatly affect releases.

2. Downstream valves (i.e., Turbine Stop valves, Auxilia y Feed Pump Turbine Steam Stop valves, Steam Dump valves and Stean Drain System) are closed, or are capaole of remote manual closure in any containment isolation event.

3. MSIV bypass valves are open for only a short time during each operating cycle. They will be locked closed during mode 1 (power operation). (

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4. MSIV bypass valves can be manually closed when required to establish containment integrity.

In addition, TUGC0 proposes to establish certain operating restrictions on the use of the MSIV bypass valves. These restrictions are intended to eliminate the potential for the uncontrolled blowdown of more than one steam generator in the unlikely event of a main steam line break coincident with the short period of time in which a bypass valve may be'open. The operational contraints (to be incorporated in the CPSES Plant Operating Procedures) would confine operations to only one bypass valve and include the following steps:

Open only one MSIV bypass valve and use it to equalize the pressure across the corresponding MSIV. >

Open the MSIV associated with the open Dypass valve.

Close the bypass valve.

Open the remaining MSIVs.

TUGC0 has performed an evaluation of the impact of the MSIV bypass valve actuator replacement on plant safety., We have determined that the modification of the bypass valves and their operation with the above specified operational constraints would have no adverse impact on safety or the safety analyses presented in the CPSES FSAR.

Changes to CPSES Technical Specifications are requested as shown in Attacnment 1.

Marked up copies of the FSAR Sections showing the changes resulting from the bypass valve actuator replacement are also er: closed (Attachment 2).

These changes will be incorporated in a future FSAR amendment.

Should you have any questions or need clarificctions, please contact us.

Sincerely,

. (l wt), / I-gJ.-W. Beck BSD/grr Attachment Distribution: Original plus 40 copies t

c- S. B. Burwell A. L. Vietti i .