NSD-NRC-97-4993, Submits W Responses to 9 RAIs Re Open Items on AP600 Topics from Section 3 of Ssar

Submits W Responses to 9 RAIs Re Open Items on AP600 Topics from Section 3 of Ssar

ML20135C565
Person / Time
Site:	05200003
Issue date:	02/21/1997
From:	Mcintyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Quay T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NSD-NRC-97-4993, NUDOCS 9703040125
Download: ML20135C565 (12)

Text

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Westinghouse Energy Systems Bm 355 ,

Pittstrygh Pennsylvania 15230 0355 j Electric Corporation NSD-NRC-97-4993 DPC/NRC0747 Docket No.: STN-52-003 February 21,1997 Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555 TO: T.R. QUAY

SUBJECT:

WESTING 110USE RESPONSES TO NRC REQUESTS FOR ADDITIONAL INFORMATION ON TIIE AP600.

Dear Mr. Quay:

Enclosed are three copies of the Westinghouse responses to open items on AP600 topics. Responses to nine RAls are included in this transmittal. RAI 410.261 provides information on Section 9 of the SSAR. Responses to RAI 440.571, Revision 1, discusses the OSU Test Analysis Report. Responses to RAls 260.83,84,85,86,87,88, and 89 address questions on Section 3 of the SSAR.

The NRC technical staff should review these responses as a part of their review of the AP600 design.

These responses close, from a Westinghouse perspective, the addressed questions. The NRC should inform Westinghouse of the status to be designated in the "NRC Status" column of the OITS.

Please contact Brian A. McIntyre on (412) 374-4334 if you have any questions concerning this transmittal.

A.

Brian A. McIntyre, ianager Advanced Plant Safety and Licensing l jml Enclosures f

cc: T. Kenyon, NRC - (w/o enclosures) /

W. Iluffman, NRC - (w/ enclosures) Q ,

N. Liparulo, Westinghouse - (w/o enclosures) h LV 9703040125 970221 l PDR ADOCK 05200003 i E PDR . l 040030 asymppsyy,gg L

ENCLOSURE TO WESTINGHOUSE LETTER NSD-NRC-97-4993 FEBRUARY 21,1997 l

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a NRC REQUEST FOR ADDITIONAL INFORMATION 9; i 84 Question 260.83 Re: OITS 4116 Is it Westinghouse's position that RP C.4 of Regulatory Guide (RG) 1.29 is incongruous with the " concept of graded QA"? Also, please explain what Westinghouse's " concept of Graded QA" is and where that concept is defined in the rtandard safety analysis report (SSAR).

Response: j i

The " concept of a graded QA" is the equipment ranking system defined in SSAR Section 3.2, " Classification of Structures, Components, and Systems." The seismic classification complies with the criteria established in 1 Regulatory Guide 1.29. Seismic Category I requirements are applied to safety-related equipment as defined in l Subsection 3.2.1. A safety classification designation is defined, as well as the use of codes and standards, that conforms to the requirements of 10 CFR 50.55a. Safety-related components or systems are rated Class A, B, or C as defined in Subsection 3.2.2.2. Class A, B. and C components are treated as Seismic Category I and conform to ,

the requirements of 10 CFR 50 Appendix B. Components designated as Class D are nonsafety-related equipment that will meet requirements established by industrial quality assurance standards like the ASME Boiler and Pressure Vessel Code, Section Vill. I l

SSAR Revision: NONE l

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NRC REQUEST FOR ADDITIONAL INFORMATION Question 260.84 Re: OITS 4117 Expi:in how quality assurance requirements for the regulatory treatment of nonsafety systems, systems, and componats (RTNSS) which, Westinghouse has defined in Letter NSD-NRC-96-4670, dated March 26,1996, are also sufGUent to satisfy the regulatory requirements for seismic Category II, as described in RG 1.29, i.e., "all activities s#ecting the safety-related functions of those portions of structures, systems, and components covered under Regulatory Positions 2 and 3" of the RG?

Response

SSAR Subsection 3.2.1.1.2 contains the Westinghouse position that "the quality assurance requirements for Seismic Category 11 structures, systems and components are sufficient to provide that these components will meet the requirement to not cause unacceptable structural failure of or interaction with Seismic Category I structures." The quality assurance requirements defined in Ixtter NSD-NRC-96-4670 constitutes a Quality Assurance Program Plan used in a procurement contract to assure that the component will be designed, documented and delivered to the plant in a controlled manner Design input, including seismic design requirements for Category II, shall be contained in design requirements documents or Equipment Specifications which are also part of a procurement contract.

SSAR Revision: NONE I

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0 NRC REQUEST FOR ADDITIONAL INFORMATION Ouestion 260.85 Re: OITS 4118 Please identify all RTNSS SSCs that would also satisfy the functional and design criteria of those portions of structures, systems, and components covered under Regulatory Positions 2 and 3 of RG 1.29.

Response

RG 1.29 Regulatory Position 2 imposes Category I design requirements and 10 CFR 50 Appendix B on " portions of structurcs, systems, or components whose continued function is not required but whose failure could reduce the functioning of any plant feature" included in Category 1. Regulatory Position 3 imposes Category I design requirements and 10 CFR 50 Appendix B on " portions of structures, systems, or components that form interfaces between Seismic Category I and non-Seismic Category I requirements."

AP600 does not have any identified RTNSS structures, systems, and components that fall under the definitions of Regulatory Position 2 or 3.

SSAR Revision: NONE 260.85 W-Westinghouse

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i NRC REQUEST FOR ADDITIONAL INFORMATION 7  :

Question 260.86 Re: OITS 4119 How would RTNSS QA requirements as defined in NSD-NRC-96-4670 address interface design requirements identified in RP C.3.?

Response

As indicated in the response to RAI 260.85, AP600 does not have any identified RTNSS structures, systems and components that " form interfaces between Seismic Category I and non-Seismic Category I requirements" identified l

in Reg. Guide 1.29, RP 3. QA requirements defined in NSD-NRC-96-4670 do not apply to any components in the Regulatory Position C.3 category.

SSAR Revision: NONE i

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260.86 W-Westinghouse 1

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'NRC REQUEST FOR ADDITIONAL INFORMATION y v Question 260.87 Re: OITS 4120 i Westinghouse *s statement above appears to imply that RTNSS QA requirements as defined in NSD-NRC-964670 would also be applicable to all AP600 equipment Class D. Please clarify.

Response: ,

l QA requirements defined in NSD-NRC-96-4670 are typical of requirements that would be applicable to AP600 i equipment Class D. Some additions could be made depending on the component and the vendor. As an example, l the plant owner may impose a procedure for control of a weld process examination if a supplier qualification audit shows a vendor needs to reinforce this area. There may also be some components that are Class D Seismic Category 1, that will meet the requirements of 10 CFR 50 Appendix B.

l SSAR Revision: NONE i

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e NRC REQUEST FOR ADDITIONAL INFORMATION

=c Question 260.88 Re: OITS 4121 While the staff may agree that " industrial quality assurance standards are consistent with the guidelines for NRC Quality Group D", it is not clear how you concluded that such standards, without NRC endorsement, satisfy the provisions of Appendix B to 10 CFR 50. Please Clarify.

. Response:

Subsection 3.2.2.6 of the SSAR indicates that Class D systems, structures and component- ae subject to the requirements of standard industrial QA standards. An exception to this is when the Class D system, structure or component is classified as Seismic Category I. A Category I classification requires that 10 CFR 50 Appendix B be invoked as the appropriate QA requirements. The SSAR does not imply the industrial quality standards meet the provisions of 10 CFR 50 Appendix B.

SSAR Revision: NONE W85tiflgt10US8

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( NRC REQUEST FOR ADDITIONAL INFORMATION l

Question 260.89 Re: 4122 SSAR Section 3.2.2.2, " Application of Classification " Page 3.2-5, states, in part " Structures, systems, and components classified equipment class A, B, or C or seismic Category I are basic components as defined in 10 CFR 21." Please clarify how a " Basic Component" as defined in 10 CFR Part 21 can also be classified as Equipment Class D, as defined in SSAR Section 3.2.2.6.

Response

SSAR Section 3.2.2.2, Application of Classification, applies the " Basic Componer.t" designation to safety related Class A, B, and C components only. SSAR Section 3.2.2.6 defines Class D as nonsafety related structures, systems and components containing radioactivity where a conservative analysis must show that the potential for failure, due to a design basis event, does not result in exceeding the normal offsite doses. Consistent with the requirements of 10 CFR 21, the Class D classification is not applied to designated " Basic Components" quality requirements.

SSAR Revision: NONE l

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l 260,89 3 Westinghouse 1

l NRC REQUEST FOR ADDITIONAL INFORMATION Question 410.261 Provide the following information on the hot water heatin; system (HHS) discussed in Section 9.2.10 of the SSAR:

a. Specify the operating pressures and temperatures of the HHS piping that supply hot water to major areas of the plant.

b. Are any of the HHS lines routed into the containment that require containment isolation? If so specify the safety class and seismic category of the portions of the HHS piping at the containment penetrations between the containment isolation valves. i

c. Specify the potential consequences of a break in the HHS piping and the protective measures to prevent damage (such as flooding) on safety-related systems.

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d. Do any of the HHS lines run over or through the control room? j Response: I

a. The operating pressure and temperature of the hot water heating system (VYS) is about 300*F (supply). I 220*F (return) and 120 psig. The piping design conditions are 320*F and 200 psig.

b. No VYS lines are routed inside the containment.

c. No VYS piping is routed in rooms that contain safety-related equipment. There are no adverse consequences on safety-related components or equipment due to postulated breaks in the VYS piping routed

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in nonsafety-related areas.

d. The VYS lines are not routed over or through the main control room.

This response is consistent with Revision 10 of the SSAR and the Revision I response to RAI 410.289.

SSAR Revision:

None i

410.261-1 3 Westirgtlouse p,y, i l

Q NRC REQUEST FOR ADDITIONAL INFORMATION mr Question 440.571 Revision 1 Re: OSU FDR and TAR Over a range of several thousand seconds in many tests, the PRHR HX wide range level appears to drift upwards considerably. Explain what is occurring: is this an actual change in level, or is an instrumentation problem?

Response

A review of the data from test SBl8 suggests that the apparent upward drift of the wide range level transdocer output is an indication of an actual change in level until about 2250 seconds into the test. The interpretation of the data leading to this conclusion is as follows; )

• For this test, the indicated level in the PRHR goes to zero at about 700 seconds. Coincidentally, the rate l l

of change of the fluid temperature in the PRHR inlet header is observed to at first stop, and then continue to decrease at a very small rate to about 900 seconds. These data are interpreted as indicating that the pressure head on the hot leg side has decreased sufficiently that a slight suction is applied to the residual water in the PRHR discharge line through the heat exchanger tubes that supports a 5.0 inch head of , vater in the tubes.

• At about 930 seconds,4th stage ADS is actuated. As the PRHR feed line and the 4th stage ADS line for loop 2 share a common takeoff from hot leg 2, the pressure in the PRHR feedline is further reduced, causing the water level in heat exchanger tubes to risc further. This rise in heat exchanger water level is coincident with a rapid decrease in the temperature of the fluid in the PRHR heat exchanger inlet header to about saturation temperature at I atmosphere. Aftt.r that time the fluid temperature in the PRHR inlet header becomes and remains subcooled.

• From about 1200 seconds until about 1600 seconds, the water level in the tubes remains constant and the PRHR heat exchanger inlet header fluid temperature increases to near saturation at I atmosphere. This is taken to be the result of steam drawn into the header by condensation.

• Between about 1600 seconds and 2250 seconds, the indicated water level in the tubes again increases slightly, and the inlet header fluid t:mperature is observed to again decrease. This is consistent with the time period for which liquid flow is again measured as being discharged from the PRHR. Thus the  ;

indicated increase in water level, from about 5 inches to about 12 inches of water in the PRHR from about 1600 seconds to about 2250 seconds is interpreted as resulting from condensate forming on the inside l surfaces of the PRHR tubes.

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• After about 2250 seconds, the level measurements for the PRHR heat exchanger indicates that the water l level in the PRHR tubes again increases. As the measured outlet flow remains at about zero, this increase l 440.571-1 3 Westingflouse Rey,1

NRC REQUEST FOR ADDITIONAL. INFORMATION N

in water level is evaluated as an indication of flashing of the reference leg rather than a build up of water in the exchanger tubes.

Thus, for test SB18, the level indication for the PRHR heat exchanger is interpreted as an actual increase in the water level in the PRHR heat exchanger tubes that occur when the hot leg pressure on the PRHR heat exchanger drops below the backpressure in the outlet plenum of SG2, and again when ADS 4 actuates. Later in time when the PRHR tlow measurement drops to zero, the increase in indicated PRHR water level is interpreted as indication flashing of the levels transducer reference leg. This explanation applies to all tests for which a similar behavior was observed.

SSAR Revision: NONE 7b2 Rev.1 W Westingtiouse