ST-HL-AE-1769, Forwards Change to FSAR Page 3.5-2 Re Evaluation of Temp Detectors Installed in High Energy Piping,Inadvertently Omitted from 860617 Transmittal,Per SER (NUREG-0781) Open Item 2.Related Correspondence

Forwards Change to FSAR Page 3.5-2 Re Evaluation of Temp Detectors Installed in High Energy Piping,Inadvertently Omitted from 860617 Transmittal,Per SER (NUREG-0781) Open Item 2.Related Correspondence

ML20215B146
Person / Time
Site:	South Texas
Issue date:	09/30/1986
From:	Wisenburg M HOUSTON LIGHTING & POWER CO.
To:	Noonan V Office of Nuclear Reactor Regulation
References
CON-#486-0953, RTR-NUREG-0781 OL, ST-HL-AE-1769, NUDOCS 8610060383
Download: ML20215B146 (4)

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DfOlddibep 30,"1586 ST-HLtAE-1769 File No.:G9.18/G36.04 Mr. Vincent S. Nornan, Project Director PWR Project Direct 3 rate #5 U. S. Nuclear Regulatory Commission Washington, DC 20555 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Revised Page for the Response To Safety Evaluation Report, NUREG-0781 Open Item a2 -

Internal Missile Analysis

Reference:

(1) HL&P letter to NRC, M. R. Wisenburg to V. S. Noonan, June 17, 1986, ST-HL AE-1684

Dear Mr. Noonan:

The above reference transmitted annotated changes to the South Texas Proj ect (STP) Final Safety Analysis Report (FSAR) Section 3.5 and responses to NRC Questions which provided the results of the internal missile analysis / evaluations for the STP. These changes were submitted in response to the Safety Evaluation Report (SER), NUREG-0781 open item number 2 (Table 1.1-4 of the SER).

Since the submittal of the referenced letter, we have found a change which was inadvertently omitted from the letter. Attached please find a .

change to FSAR Page 3.5-2 regarding the evaluation of temperature detectors l installed in high energy piping.

Our previous conclusion that as a result of the analysis, no modifications to the plant design are required still remains valid.

If you should have any questions on this matter, please contact Mr. M. E. Powell at (713) 993-1328.

Very ruh yours, 8610060383 860'/30 8 '

PDR ADOCK 0500 E k M. R. Wisanburg Manager, uclear L censi -

Attachment:

Annotated changes to FSAR Page 3.5-2 Ll\nrc\bl.

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Houston Lighting & Power Company ST-HL-AE-1769 File No.: G9.18/G36.04 I Page 2 cc:

Hugh L. Thompson, Jr. , Director Brian E. Berwick, Esquire Division of PWR Licensing - A Assistant Attorney General for Office of Nuclear Reactor Regulation the State of Texas U.S. Nuclear Regulatory Commission P.O. Box 12548, Capitol Station Washington, DC 20555 Austin, TX 78711 Robert D. Martin Lanny A. Sinkin Regional Administrator, Region IV Christic Institute Nuclear Regulatory Commission 1324 North Capitol Street 611 Ryan Plaza Drive, Suite 1000 Washington, D.C. 20002 Arlington, TX 76011 Oreste R. Pirfo, Esquire N. Prasad Kadambi, Project Manager Hearing Attorney U.S. Nuclear Regulatory Commission Office of the Executive Legal Director 7920 Norfolk Avenue U.S. Nuclear Regulatory Commission Bethesda, MD 20814 Washington, DC 20555 Claude E. Johnson Charles Bechhoefer, Esquire Senior Resident Inspector /STP Chairman, Atomic Safety 6 c/o U.S. Nuclear Regulatory Licensing Board Commission U.S. Nuclear Regulatory Commission P.O. Box 910 Washington, DC 20555 Bay City, TX 77414 Dr. James C. Lamb, III M.D. Schwarz , Jr. , Esquire 313 Woodhaven Road Baker & Botts Chapel Hill, NC 27514 One Shell Plaza Houston, TX 77002 Judge Frederick J. Shon Atomic Safety and Licensing Board J.R. Newman, Esquire U.S. Nuclear Regulatory Commission Newman 6 Holtzinger, P.C. Washington, DC 20555 1615 L Street, N.V.

Washington, DC 20036 Citizens for Equitable Utilities, Inc, c/o Ms. Peggy Buchorn Director, Office of Inspection Route 1, Box 1884' and Enforcement Brazoria, TX 77422 U.S. Nuclear Regulatory Commission Washington, DC 20555 Docketing 6 Service Section Office of the Secretary T.V. Shockley/R.L. Range U.S. Nuclear Regulatory Commission Central Power & Light Company Washington, DC 20555 P.O. Box 2121 (3 Copies)

Corpus Christi, TX 78403 Advisory Committee on Reactor Safeguards H.L. Peterson/G. Pokorny U.S. Nuclear Regulatory Commission City of Austin 1717 H Street P.O. Box 1088 Vashington, DC 20555 Austin, TX 78767 J.B. Poston/A. vonRosenberg City Public Service Board P.O. Box 1771 San Antonio, TX 78296 Ll\nrc\bl. Revised 5/22/86

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w l Table 3.5-2 lists and describes the barriers utilized for missile protection. I 3.5.1.1 Internally Generated Missiles outside the Containment. Seismic Category I structures, systems, and components outside the Containment whose failure could result in radiological consequences in ancess of 10CFR100 guidelines or which are required for attaining and maintaining a safe shutdown during normal or accident conditions are listed in Table 3.5 1.V External missile protection provisions anc rezerences to applicaele system descriptions and drawings that demonstrate separation and independence are listed in Table 53 3.5 1. 4e644et' {nternal missile protectioq;n.;;i:2 are indicatec in Table 7 3.5 1. 717.21 ir.n rr. 1 =i::14*-desig. p::t::ti:n ;;;.i:i x . ft:1d it; -

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1. etential-oeurces-of =ieeiler e . Oh hi M PebM M'Som e High-pressure systems f Coner / 1 58 MM vb Grbasr<cakd m Sa Iden arc cathc" C emPeneah N

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e c enpw k tc.r/ q ag c3llMcfb ' " 'E M I Systems outside the Containment were reviewed to determine sources of .q211.I missiles.4 The results of this review are discussed in the following section.

M M5 3.5.1.1.1 High Pressure Systems: Valve bonnats and stems as+ therne- l36 wellslare the potential missiles associated with high pressure , systems outside the Containment, gmy MM ""f O

[ Temperature-er-ether. detectors installedken, piping e in ella_are evaluated as potential miss11es df-a-failure-of-a-eingle-etroumferential-weld-would w .,

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faf1=e of m circumfarantial-weld-is needed-for-e ? tecter ;e i;;;r.e am . 35

-eisri-Is.. In addition, because of the spatial separation of redundant safe-ty-related equipment, a small missile such as a detector, assuming the circuc-ferential weld fails completely, is not likely to hit redundant safety related squipment.

Two types of valve components, valve stems and valve bonnets, are potential missiles. Valves in high pressure systems have been reviewed as potential missile sources. The provisions that valves have bolted bonnets or secondary retention devices, and that they be designed to ASME III requirements effec-tively eliminates credible sources of valve component missiles.

Valves of ANSI 900 psig rating and above, constructed in accordance with Section III of the ASME Roiler and Pressure Vessel Code, are pressure seal bonnet type valves. For pressure seal bonnat valves, valve bonnets are prevented from becoming missiles by the retaining ring, which would have to fail in shear, and by the yoke, which would capture the bonnet or reduce 36 bonnet energy.

Seesuse of the highly conservative design of the retaining ring of these valves (safety factors in excess of 8 may be used), bonnet ejection is highly improbable and hence bonnets are not considered credible missiles.

Most valves of ANSI rating 600 psig and below are valves with bolted bonnets. i Valve bonnets are prevented from becoming missiles by limiting stresses in the 3.5 2 Amendment 53

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Insert for Page 3.5-2/Section 3.5.1.1.1

. . .where they are only attached by a threaded connection. k'here they are attached by a threaded connection with a seal weld, the seal weld prevents the connection from disengaging because of vibration, cyclical stresses etc. and these detectors are not postulated as missiles, k'here they are attached by welding, the design strength of the completed weld is at least equal to or  ;

greater than the base materials and therefore, these detectors are not postulated as missiles. j l

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