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#REDIRECT [[ST-HL-AE-1582, Clarifies 851024 Response to NRC Request for Study of Jet Impingement Effects in Break Exclusion Area of Main Steam & Feedwater Piping.Encl NRC & Safety Evaluation Cited to Support Claim That Study Lacks Justification]]
| number = ML20140B734
| issue date = 01/20/1986
| title = Clarifies 851024 Response to NRC Request for Study of Jet Impingement Effects in Break Exclusion Area of Main Steam & Feedwater Piping.Encl NRC 770606 Ltr & Safety Evaluation Cited to Support Claim That Study Lacks Justification
| author name = Wisenburg M
| author affiliation = HOUSTON LIGHTING & POWER CO.
| addressee name = Noonan V
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000498, 05000499
| license number =
| contact person =
| case reference number = CON-#186-816, RTR-NUREG-0800, RTR-NUREG-800
| document report number = OL, ST-HL-AE-1582, NUDOCS 8601270114
| package number = ML20140B735
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 3
}}
 
=Text=
{{#Wiki_filter:p. ~ q The Light Company n-i- us,w- im>x im n-u.nmxas mm mmmen January 20, 1986 ST-hl-AE-1582 File No.: G9.17, N3.8.10 Mr. Vincent S. Noonan, Project Director PWR Project Directorate #5 U. S. Nuclear Regulatory Commission Washington, CC    20555 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Clarification of STP Position Regarding Break Exclusion Zone Design Basis
 
==Reference:==
Letter ST-HL-AE-1436, dated 10/24/85, M. R. Wisenburg to G. W. Knighton
 
==Dear Mr. Noonan:==
 
The intent of this letter is to clarify HL&P's position regarding recent requests from NRC reviewers to perform an evaluation of the effects of jet impingement in the break exclusion area of the main steali and feedwater piping. The NRC's request is based on Branch Technical ?osition (BTP) ASB 3-1 (contained in NUREG 0800, dated July, 1981).      However,.since STP conforms to the requirements of NUREG 75/087, Section 3.6, (the licensing basis for STP) the requested evaluation is beyond the STP licensing basf.s and is therefore considered a backfit.
In response to initial NRC requests on this subject, the feasibility of performing the additional jet impingement evaluation was investigated.
Although HL&P has a high degree of confidence that such an evaluation would be successful, our investigation has shown that the effort required would be significant. We further believe that such an evaluation is unnecessary, As stated in FSAR Table 3.6.1-2, entitled " Design Comparison to ASB 3-1,"
the Isolation Valve Cubicle (IVC) and essential equipment is designed to the environmental and pressurization effects of a single area circumferential l
break. No breaks are postulated in break exclusion piping in the area of the torsional and bending restraints. The justification for this design basis is as follows:
o    The criteria for the design of break exclusion zone piping was established prior to the issuance of NUREG 0800 in 1981. The STP criteria (delineated in FSAR Sections 3.6.1 and 3.6.2, and the reference letter) conforms to the requirements of BTP APCSB 3-1
!                                    8601270114 851020 PDR    ADOCK 05000498                        pd [
                                      ^                    "
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ST-HL-AE-1582 File No.: G9.17, N3.8.10 Page 2 Houston Lighting & Power Company (contained in NUREG 75/087). The STP position regarding paragraph B.l.a (1) of BTP ASB 3-1 is documented in FSAR Section 3.6.2.1.1 (5) and in FSAR Table 3.6.1-2. The NRC previously issued a Safety
,                        Evaluation Report (see attachment) on the subject of dynamic effects of postulated pipe whip failures outside of containment. This document confirmed the acceptability of designing the main steam and feedwater isolation valve rooms (in the IVC) for the environmental and subcompartment pressurization effects of a single area break with no stipulations regarding consideration of jet impingement effects.
o      In several cases, the staff has granted relief from the requirement to postulate arbitrary intermediate breaks in piping which is not part of a break exclusion zone. In light of the NRC's safety evaluations supporting these actions, the requirement to evaluate jet impingement effects for breaks in the break exclusion portions of the main steam and feedwater piping has no technical justification.
In summary, the STP design basis regarding pipe breaks in the break exclusion piping in the main steam and feedwater isolation valve rooms (in the IVC) is as follows: Essential equipment is designed to be protected from or qualified to the environmental effects resulting from a full circumferential break (single area) in the main steam or main feedwater piping. Essential equipment is also designed to be protected from the jet impingement and pipe whip effects resulting from a full circumferential break postulated in the~
branch piping associated with the main steam or main feedwater piping.
If you should have any questions on this matter, please contact 4            Mr. M. E. Powell at (713) 993-1328.
Very trul yours, xi M. R. Wi nburg Manager,    clear  cen ng DMC/yd
 
==Attachment:==
Letter from Olan Parr to G. W. Oprea, dated 6/6/77.
Ll/NRC/je
 
l ST-HL-AE-1582 File No.: G9.17 Houston Lighting & Power Company                                              Page 3 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 i                U.S. Nuclear Regulatory Commission                      P.O. Box 12548, Capitol Station 1
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 j                Senior Resident Inspector /STP                        Chairman, Atomic Safety &
,                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. Shnn Atomic Safety and Licensing Board J.R. Newman, Esquire                                  U.S. Nuclear Regulatory Commission Newman & Holtzinger, P.C.                              Washington, DC 20555 1615 L Street, N.W.
3 Washington, DC 20036                                  Mr. Ray Goldstein, Esquire 1001 Vaughn Building Director, Office of Inspection                        807 Brazos and Enforcement                                    Austin, TX 78701 U.S. Nuclear Regulatory Commission Washington, DC 20555                                  Citizens for Equitable Utilities, Inc.
c/o Ms. Peggy Buchorn T.V. Shockley/R.L. Range                              Route 1, Box 1684 Central Power & Light Company                        Brazoria, TX 77422 P.O. Box 2121 Corpus Christi, TX 78403                              Docketing & Service Section i
Office of the Secretary H.L. Peterson/G. Pokorny                              U.S. Nuclear Regulatory Commission City of ' Austin                                      Washington, DC 20555 P.O. Box 1088                                          (3 Copies)
Austin, IX 78767 Advisory Committee on Reactor Safeguards J.B. Poston/A. vonRosenberg                          U.S. Nuclear Regulatory Conunission
!                City Public Service Board                              1717 H Street P.O. Box 1771                                        Washington, DC 20555 San Antonio, TX 78296
;                                                                                                            Revised 12/3/83 Ll/NRC/je
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