ML20141E463

Forwards Request for Addl Info to Aid in Closeout of Draft SER Open Item Re MSIV Closure on Any Safety Injection Signal

ML20141E463
Person / Time
Site:	South Texas
Issue date:	01/02/1986
From:	Kadambi N Office of Nuclear Reactor Regulation
To:	Goldberg J HOUSTON LIGHTING & POWER CO.
References
NUDOCS 8601070698
Download: ML20141E463 (6)

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AN 02 m Docket Nos. 50-498 and 50-499 Mr. J.H. Goldberg Group Vice President-Nuclear-Houston Lighting and Power Company P.O. Box 1700 Houston, TX 77001

Subject:

South Texas Projects, Units 1 and 2 - Request for Additional Information This request for additional information is being made to progress toward close-out of an open item in the Draft Safety Evaluation Report concerning main steam iso.lation vaive (MSIV) closure on any SI signal. This issue had been raised previously as Question 440.57N and during the ICSB' audit. The request for information, enclosed herewith as. Question 440.80N, provides the reasons for.the staffs concerns and also the reasons for the inadequacy of information received so far.

Please inform us as to your schedule for responding.

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Please contact me at 301_492-7272 if you have any questions.

Sincerely,

/s/

N. Prasad Kadambi Project Manager PWR Project Directorate #5 Enclosure cc: See next page Distribution 4:Mw M C~PDR Local PDR PDf5 Reading File H.. Thompson OELD E. Jordan B. Grimes J. Partlow P. Kadambi M. Rushbrook w ACRS (10)

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\...../ . ,, w Docket Nos. 50-498 and 50-499 Mr. J.H. Goldberg Group Vice President-Nuclear Houston Lighting and Power Company P.O. Box 1700 Houston..TX 77001

Subject:

South Texas Projects, Units 1 and 2 - Request for Additional Infonnation This request for additional information is being made to progress toward close-out of an open item in the Draft Safety Evaluation Report concerning main steam isolation valve (MSIV) closure on any SI signal. This issue had been raised previously as Question 440.57t; and during the ICSB audit. The request for infonnation, enclosed herewith as Question 440.80N, provides the reasons for the staffs concerns and also the reasons for the inadequacy of information received so far.

Please inform us as to your schedule for responding. Please contact me at

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301-492-7272 if you have any questions.

Sincerely,

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N. Prasad Kadambi a Project Manager PWR Project Directorate #5 Enclosure cc: See next page

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i Mr. J. H. Goldberg Houston Lighting and Power Comoany South Texas Project CC' Brian Berwick, Esq. Resident Inspector / South Texas

Assistant Attorney General Project Environmental Protection Division c/o U.S. Nuclear Regulatory Commission P. O. Box 12548 P. O. Box 910 Capitol Station Bay City, Texas 77414 Austin, Texas 78711 Mr. Jonathan Davis Mr. J. T. Westermeir Assistant City Attorney Manager, South Texas Project City of Austin Houston Lighting and Power Company P. O. Box 1088

~P. O. Box 1700 Austin, Texas 78767 Houston, Texas 77001 Ms. Pat Coy Mr. H. L. Peterson Citizens Concerned About Nuclear Mr. G. Pokorny- Power City of Austin 5106 Casa Oro P. O. Box 1088 San Antonio, Texas 78233 Austin, Texas 78767 Mr. Mark R. Wisenberg Mr. J. B. Poston Manager, Nuclear Licensing Mr. A. Von Rosenberg Houston Lighting and Power Company City Public Service Boad P. O. Box 1700 P. O. Box 1771 Houston, Texas 77001 San Antonio, Texas 78296

• Mr. Charles Halligan Jack R. Newman, Esq. Mr. Burton L. Lex Newman & Holtzinger, P.C. Bechtel Corporation 1615 L Street, NW P. O. Box 2166 Washington, D.C. 20036 Houston, Texas 77001 Melbert Schwartz, Jr., Esq. Mr. E. R. Brooks Baker & Botts Mr. R. L. Range One Shell Plaza Central Power and Light Company Houston, Texas 77002 P. O. Box 2122 Corpus Christi, Texas 73403 Mrs. Peggy Buchorn Executive Director Citizens for Equitable Utilities, Inc.

Route 1, Box 1684 Brazoria, Texas 77422 l

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I Houston Lighting & Power Company 2- South Texas Project CC*

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Mr. Lanny Sinkin Citizens Concerned About Nuclear Power 3022 Porter Street, NW #304 Washington, D.C. 20008 Mr. S. Head, Representative Houston Lighting and Power Company Suite 1309 7910 Woodmont Avenue Bethesda, Maryland 20814 i

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g ENCLOSURE SOUTH TEXAS PROJECT REQUEST FOR ADDITIONAL INFORMATION 440.80N a. In Question 440.57N the staff requested information regarding the effect of the STP design for MS!V closure on mitigation of steam generator tube rupture (SGTR) or small break LOCA.

It is our understanding that the MSIVs would automatically close on low RCS pressure SI actuation, while the Westinghouse emergency response guidelines (ERGS) are based on use of the condenser for steam dump when it is available and thus assume that the MSIVs for intact SGs remain open. Your response indicated that for this type of event the MSIVs would be reopened, and that the time required for reopening the MSIVs would be offset by the time it takes to isolate a ruptured SG in the event of SGTR. You concluded that automatic closure of the MSIVs on any SI signal would not adversely affect recovery. We do not concur with this conclusion for the reason discussed below.

In out conference call of December 3, 1985, on this subject, you stated that several operations are required prior to reopening the MSIVs, including SI reset and equalization of MSIV upstream and downstream pressures. First, it is not clear that SI Reset would be possible at the times when MSIV opening is necessary.

Second, it is not clear whether the STP emergency operating procedures (E0Ps) for SGTR and small break LOCA mitigation reflect these additional steps for re-establishment of steam dump to the condenser, and whether this will be part of operator training, including simulator runs. It is not clear that this mode of plant operation is consistent with our aoproval of the generic Westinghouse ERGS. Please address the above concerns.

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b. Please provide detailed information on the effect of STP design for MSIV closure on the frequency of challenges to the MSIVs,

, steam generator safety valves (SVs) and atmospheric dump valves (ADVs). Consider the possible effect of more frequent challenges on the reliability of these valves, For SVs consider previous operating incidents during which a SV was actuated and then did not reseat properly, thus causing excessivesteamleakage(e.g.,GinnaSGTRevent). Can the number of lifetime design cycles for these components be exceeded as a result of this design? Your response should consider operating history during various modes of operation, including testing and spurious actuations.

c. The evaluations currently conducted by the Westinghouse Owners Group (WOG) to address SGTR accident mitigation do not assume closure of the MSIVs on SI signal. The operator action times assumed in these analyses are based on typical MSIV closure actuation systems, which are not the same as for STP. Thus, it is not apparent that these analyses are representative of the STP plant. Therefore, unless it can be demonstrated that the WOG analyses clearly apply to STP, provide the results of plant specific analyses that address the spectrum of SGTR concerns being addressed by the WOG, These include but are not limited to, the required time to stop the primary-to-secondary break flow and the time margin to overfill.

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