ML20199F442

Forwards Open Items Associated w/AP600 Ser,Section 3.6.1, Piping Failures Outside Containment

ML20199F442
Person / Time
Site:	05200003
Issue date:	12/17/1997
From:	Joseph Sebrosky NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9802040013
Download: ML20199F442 (5)

Text

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i December 17, 1997 Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230

SUBJECT:

OPEN ITEMS ASSOCIATED WITH AP600 SAFETY EVALUATION REPORT (SER)

SECTION 3.6.1 " PIPING FAILURES OUTSIDE CONTAINMENT"

Dear Mr. Liparulo:

The Plant Systems Branch has provided the subject SER to the projects staff. However, the SER contained some open items. These open items have been extracted from the SER and can be found in the anclosure to this letter.

You have requested that portions of the information submitted in the June 1992, application for design certification be exempt frcm mandatory public disclosure. While the staff has not completed its review of your request la accordance with the requirements of 10 CFR 2.700, that portion of the submitted information is being withheld from public disclosure pending the staff's final determination. The staff concludes that these follow on questions do not contain those portions of the information for which exemption is sought.. However, the staff will withhold this letter from public disclosure for 30 calendar days from the date of this letter to allow Westing-house the opportunity to verify the staffs conclusions. If, after that time, you do not request that all or portions of the information in the enclosures be withheld from public disclosure in accor-dance with 10 CFR 2.790, this letter will be placed in the Nuclear Regulatory Commission Public Document Room.

if you have any questions regarding this matter, you may contact me at (301) 415-1132.

l Sincerely, original signed by:

Joseph M. Sebrosky, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation j}

Docket No.52-003

Enclosure:

As stated cc w/ encl: See next page DISTRIBUTION: EC PM CEM ElCDPY See next page DOCUMENT NAME: A:SPLB_361.RAI To receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enc!osure "N" = No copy OFFICE PM:PDST:DRPM SPLB:DSSA l D:PDST:DRPM l NAME JMSebrosky:sg /4h CCarpenter (& TRQuay W DATE 12/9/97 // l 12/ll(/97 12A1!97

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Westinghouse Electric Corporation AP600 1 cc: Mr. B. A. McIntyre Ms. Cindy L Haag >

Advanced Plant Safety & Licensing Advanced Plant Safety & Licensing  !

Westinghouse Electric Corporation Westinghouse Electric Corporation Energy Systems Business Unit  !

Energy Systems Business Unit P.O. Box 355 Box 355 Pittsburgh, PA 15230 Pittsburgh, PA 15230 Enclosure to be distributed to the following addressees after the result of the proprietary evaluation is received from Westinghouse:

Mr. Russ Bell Ms. Lynn Connor Senior Project Manager, Programs DOC-Search Associates Nuclear Energy Institute Post Office Box 34 1776 i Street, NW Cabin John, MD 20818 Suite 300 Washington, DC 20006-3706 Mr. Robert H. Buchholz GE Nuclear Energy Dr. Craig D. Sawyer, Manager 175 Curtner Avenue, MC-781 Advanced Reactor Programs San Jose, CA 95125 -

GE Nuclear Energy

--175 Curtner Avenue, MC-754 Mr. Steding Franks San Jose, CA 95125 U.S. Department of Energy NE-50 Barton Z. Cowan, Esq 19901 Germantown Road Eckert Seamans Chod & Mellott Germantown, MD 20874 600 Grant Street 4;r.J Floor Pittsburgh, PA 15219 Mr. Charles Thompson, Nuclear Engineer AP600 Certification Mr. Frank A. Ross NE-50 U.S. Department of Energy, NE-42 19901 Germantown Road Office cf LWR Safety and Technology Germantown, MD 20874 19901 Germantown Road Germantown, MD 20874 Mr. Ed Rodwell, Manager PWR Design Certification Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303

, 4 OPEN ITEMS FOR AP600 SSAR SECTION 3.6.1 POSTUl.ATED PIPING FAILURES IN FLUID SYSTEMS INSIDE/OUTSIDE CONTAINMENT j The staff acknowledges that some of the following issues have been discussed previously on earlier occasions. However, repetition appears necessary given the need for further clarity and the possible incorporation of earlier RAI response text in the AP600 SSAR. Open items follow.

410.396F Identify all systems with high-energy lines outside containment. (OI 3.6.12) l 410.397F Identify all syste.us with moderate energy lines outside containment.- (OI 3.6.1-3) l 410.398F Provide pipe break analyses. The response to RAI question 410.76 was an interim response. (OI 3.6.1-4) 410.399F Provide analysis for the failure of non-seismic Category I systems. (OI 3.6.1-5) 410.400F Where restraints are used to ensure protection of safety-related equipment from the dynamic effects of pipe failure, Westinghouse should provide justification why separation and protective structures were not used. (OI 3.6.1-6) 410.401F Clarify how RTNSS and DID systems will be protected from pipe failure and how safety-related systems will be protected from pipe failures in these systems.

Identify all RTNSS and DID systems that require protection from pipe failures.

'(013.6.1-7)

. 410.402F As appropriate, include text from the following responses to the staff % requests for additionalinformation (RAI)in the AP600 SSAR: 410.76,410.79,410.81, 410.82,410.85.

r 410.403F Standard Review Plan (SRP) section 3.6.1 specifies that the plant design for protection against postulated pipe failures outside containment include high- and moderate-energy fluid system piping. With regard to moderate-energy oiping, the staff has implemented the guidance of section 3.6.1 to emphasize that protection against the piae failure of non-seismic moderate-energy piping should be analyzed for both pipe breaks (e.g., double-ended guillotine break ) and pipe cracks.

Containment environmental consequences from such a moderate-energy pipe break could adversely impact essential equipment, which likely have not been considered in other analyses.

AP600 analysis for moderate energy piping outside containment needs to properly consider protection against postulated pipe failures resulting from pipe breaks.

(The staff acknowledges that SRF section 3.6.2, Location and Dynamic Effects of Postulated Piping Failures," provides guidance on the analysis of both seismic and non-seismic moderate-energy piping for pips cracks only.)

Enclosure

410,413F -

Design basis events are routinely evaluated and addressed by plant design and procedures. When the design basis threat has been addressed, less-than-design-basis events may then become the worst-caso events and their impact should be evaluated to ensure that the consequences are bounded by the design-basis event analysis. These type of ever.ts may result in conditions not readily seen, considered, or properly addressed. In such cases, it may be prudent to revisit previous assumptions about the adequacy of plant design and procedures.

With regard to protection against fluid system pipe failures for high- and moderate-energy piping, AP800 ant. lysis needs to properly consider the above type of event. (Maine Yankee Event Report 97-009-01 provides information concoming an operating plant occurrence that illustrates the staff's concem.)

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