MHI's Responses to US-APWR DCD RAI No. 580-4584, SRP ...MHI Ref: UAP-HF-10215 Subject: MHI's Responses to US-APWR DCD RAI No. 580-4584 Reference: 1) "Request for Additional Information

AtMITSUBISHI HEAVY INDUSTRIES, LTD.

16-5, KONAN 2-CHOME, MINATO-KUTOKYO, JAPAN

July 22, 2010

Document Control DeskU.S. Nuclear Regulatory CommissionWashington, DC 20555-0001

Attention: Mr. JefferyA. Ciocco

Docket No. 52-021MHI Ref: UAP-HF-10215

Subject: MHI's Responses to US-APWR DCD RAI No. 580-4584

Reference: 1) "Request for Additional Information No. 580-4584 Revision 2, SRP Section:03.02.02 - System Quality- Group Classification," dated 5/10/2010.

With this letter, Mitsubishi Heavy Industries, Ltd. ("MHI") transmits to the U.S. NuclearRegulatory Commission ("NRC") a document entitled "Response to Request for AdditionalInformation No. 580-4584, Revision 2."

Enclosed are the responses to 7 RAIs contained within Reference 1. This transmittalcompletes the response to this RAI.

Please contact Dr. C. Keith Paulson, Senior Technical Manager, Mitsubishi Nuclear EnergySystems, Inc. if the NRC has questions concerning any aspect of this submittal. His contactinformation is provided below.

Sincerely,

Yoshiki Ogata,General Manager- APWR Promoting DepartmentMitsubishi Heavy Industries, LTD.

Enclosure:

1. Response to Request for Additional Information No. 580-4584, Revision 2

CC: J. A. CioccoC. K. Paulson

Contact InformationC. Keith Paulson, Senior Technical ManagerMitsubishi Nuclear Energy Systems, Inc.300 Oxford Drive, Suite 301Monroeville, PA 15146E-mail: ck [email protected]: (412) 373-6466

Docket No. 52-021MHI Ref: UAP-HF-10215

Enclosure 1

UAP-HF-10215Docket No. 52-021

Response to Request for Additional Information No. 580-4584,Revision 2

July, 2010

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION

7/21/2010

US-APWR Design Certification

Mitsubishi Heavy Industries

Docket No. 52-021

RAI NO.: NO. 580-4584 REVISION 2

SRP SECTION: 03.02.02 - SYSTEM QUALITY GROUP CLASSIFICATION

APPLICATION SECTION: 3.2.2

DATE OF RAI ISSUE: 511012010

QUESTION NO. 03.02.02-10:

The response to RAI 03.02.02-3 deleted reference to a graded QA approach, but did notdefine the process or what special treatment applies to nonsafety-related risk significantSSCs. Clarify the process and what unique classification and special treatment (includingany supplemental design requirements and quality assurance measures) apply tononsafety-related, risk-significant SSCs in order to distinguish them from nonsafety-relatedSSCs having no risk significance. For example, if the RTNSS/PRA process and D-RAP willbe used to develop special treatment requirements to ensure reliability assumed in the PRA,the applicant should so clarify and identify how and when those requirements will beverified.

Reference: MHIs Response to US-APWR DCD RAI No. 276-2043; MHI Ref: UAP-HF-09232; Dated May 8, 2009; ML091320435.

ANSWER:

DCD Section 17.4 discusses the Design Reliability Assurance Program (D-RAP) and whatis considered in designating an SSC to be risk-significant. SSCs are identified as risk-significant based on the performance of importance analyses, seismic margin analysis,PRA results, engineering judgment, operational experience feedback and meetingsconducted by the expert panel, and are treated by the D-RAP. DCD Section 17.4 containsTable 17.4-1, which lists risk-significant SSCs.

GDC 2 requires that SSCs important to safety shall be designed to withstand the effects ofearthquakes without loss of capability to perform their safety functions. In order to comply

3.2.2-1

with GDC 2, MHI will revise the description of DCD Subsection 3.2.2.5 to include the risk-significant, non-safety related SSCs that are identified with the Seismic Event rationale

(SM) in the.Table17.4.

This process will be applied to the final US-APWR design to ensure that all appropriatenon-safety related, risk-significant SSC's within the scope of the DCD are captured. TheseSSC's will be provided special treatment requirements to ensure reliability assumed in thePRA in accordance with the D-RAP.

Impact on DCD

See Attachment 1 for a mark-up of DCD Tier 2, Section 3.2 changes to be incorporated.- Revise the first and second paragraphs and add the last paragraph in Subsection 3.2.2.5to read as follows:

"'3.2.2.5 Other Equipment Classes

Equipment Class 5Equipment Class 5 is assigned to non-safety related components that are not part of theRWMS and not within the purview of RG 1.26 (Reference 3.2-13). Equipment Class 5 isalso assigned to components that are listed as "risk-significant, non-safety related" basedon the seismic event in Section 17.4. In addition, this equipment class is also assigned tonon-safety related structures and structural components, instrumentation, controls, andelectrical components.Equipment Class 5 SSCs are classified NS or seismic category II. Seismic category II SSCsmeet the pertinent QA requirements of 10 CFR 50, Appendix B. Codes and standards, asdefined in the design bases, are applied to Equipment Class 5 components.

The COL Applicant is to apply DCD methods of equipment classification and seismiccategorization of risk-significant non-safety related SSCs based on their safety roleassumed in the PRA and treatment by the D-RAP."

- Add the following Combined License Information in Table 1.8-7and subsection 3.2.3 toread as follows.

COL 3.2(6) The COL Applicant is to apply DCD methods of equipment classification andseismic categorization of risk-significant, non-safety related SSCs based ontheir safety role assumed in the PRA and treatment by the D-RAP

Impact on COLA

There is no impact on the COLA.

Impact on PRA

3.2.2-2

There is no impact on the PRA.

3.2.2-3


7/21/2010



Docket No. 52-021




DATE OF RAI ISSUE: 5/1012010


The responses to RAIs 03.02.02-5, 03.02.02-6, and 03.02.02-8 include specific editions ofcodes and standards applicable to a summary of mechanical components and stated thatadditional codes and standards or later editions of codes and standards will be applied asrequired during the development of detailed design specifications. However, the DCD wasnot updated to include these codes and standards and, the response to RAI 03.02.02-9,refers to the design basis for codes and standards applicable to Equipment Class 5, ratherthan identifying the specific codes and standards. Identify the process, including updatingthe DCD, that will be used to verify that the latest editions of codes and standards endorsedby the NRC will be applied to the design and procurement of mechanical components.

References:

MHI's Response to US-APWR DCD RAI No. 276-2043; MHI Ref: UAP-HF-09195; DatedApril 24, 2009; ML091180436. [Questions 1, 2, 4, and 9]

MHI's Response to US-APWR DCD RAI No. 276-2043; MHI Ref: UAP-HF-09232; DatedMay 8, 2009; ML091320435. [Questions 3 and 5-8]

ANSWER:

MHI will review the latest version of codes and standards in support of design andprocurement efforts. These latest codes and standards, when endorsed by the NRC, will beapplied to the design and procurement of mechanical equipment within the scope of the

US-APWR DCD.

3.2.2-4

Impact on DCD

There is no impact on the DCD.

Impact on COLA


Impact on PRA


3.2.2-5


7/21/2010



Docket No. 52-021






The DCD and RAI responses do not appear to include supplemental requirements (specialtreatment) for underground piping systems and it could not be determined if non-metallicpiping would be used in important to safety underground applications. Clarify if any non-metallic piping or lined piping will be used in any ASME class piping or non safety-relatedbut important-to-safety piping and, if so, specify the applications, associated quality groupclassifications, quality assurance requirements, supplemental requirements andcodes/standards used.

ANSWER:

Any ASME class piping, and any piping listed as Seismic Event Rational in Table 17.4 isnot applied underground piping system or lined piping system except ESWS and is notapplied non-metallic piping.

MHI will revise the DCD to change ESWS piping materials to polyethylene lined carbonsteel from epoxy lined carbon steel.

Quality group, Codes and standards, seismic category of this piping is as follows and showon Table3.2-2 item13 ESWS.

Impact on DCD

3.2.2-6

This change impacts Revision 2 of the DCD as follows. The lining material of ESWS pipingis changed from epoxy to polyethylene. See Attachment 1.

1. Revise Subsection 9.2.1.2.2.5, "Piping"

Carbon steel piping designed, fabricated, installed and tested in accordance with ASMESection III, Class 3 requirements, is used for the safety-related portion of the ESWS. Pipingis arranged to permit access for inspection. Underground piping is epfy Polyethylene linedcarbon steel and placed in trenches. Manholes are provided for periodic piping inspection.

Impact on DCD

There is no impact on the DCD

Impact on COLA


Impact on PRA


3.2.2-7


7/21/2010



Docket No. 52-021






DCD Table 3.2-2 identifies the CWS (item 59) as equipment class 9 with no quality group.The applicant is requested to clarify why the CWS is not considered Equipment Class 4(Quality Group D) to be consistent with quality group information in SRP 10.4.5. Theapplicant is also requested to verify that all systems that may contain radioactivity areappropriately classified consistent with Quality Groups A, B, C, or D and designed to RG1.143.

ANSWER:

The US-APWR CWS is not safety-related and it does not have any safety-relatedcomponents or functions. The CWS is not a RWMS. It is designed and operated tominimize the potential for radioactive contamination. The system is not expected to beradioactively contaminated during normal plant operations and even under transientconditions involving radioactive contamination of the secondary side of the plant, the CWSis not expected to contain measurable amounts of radioactive materials. Therefore, theQuality Group of US-APWR CWS components is not classified as Quality Group B, C, or D

components in RG 1.26 and the guidance provided in RG 1.143 does not apply. Moreover,leakage due to CWS failure can not reach safety-related equipment located in Category I

plant structures as described in Subsection 3.4.1.3. Therefore, the CWS componentsequipment are classified as "Class 9", consistent with the definition provided in Subsection3.2.2, with a Quality Group of "N/A" as identified in the Table 3.2-2.

Impact on DCD


3.2.2-8

Impact on COLA


Impact on PRA


3.2.2-9


7/21/2010



Docket No. 52-021






The response to RAI 03.02.02-7 references the response to RAI 03.02.01-12 regarding theapplication of the terms "safety-related" and "important to safety" with respect to the seismicclassification of SSCs in satisfying compliance with GDC 2 and stated that, "Additionalquality standards are applied to non safety-related SSCs commensurate with the functionsof the SSC and contribution to plant safety." However, neither response mentions risk-significant SSCs or the PRA process as it is used to classify non safety-related, risk-significant SSCs with respect to Quality Group or make any changes to the DCD regardinguse of these terms. Clarify to what extent SSCs that are non safety-related but areimportant-to-safety are identified and classified so that they are designed to appropriatequality standards. Also, the term "safety-related" should be replaced with the term "importantto safety" in DCD 3.2.2 and 3.1.1.1 in order to satisfy GDC 1.

ANSWER:

Based on the PRA process described in Section 17.4, the risk-significant, non safety-related SSCs that are listed in Table 17.4-1 for Seismic Event (SM) in the "Rational" columnwill be categorized as seismic Category IH and classified as Equipment Class 5.

Impact on DCD

Refer to the DCD impact for Question 03.02.02-10 of this RAI response.

Impact on COLA


3.2.2-10

Impact on PRA


3.2.2-11


7/21/2010



Docket No. 52-021




DATE OF RAI ISSUE: 511012010


Based on the responses to RAI 287-2041, questions 03.02.01-13 and 03.02.01-14 and DCDSection 14.3, it is understood that the applicant will apply ITAAC for important to safetyseismic Category II SSCs. Confirm that quality group classifications for all important-to-safety SSCs will be verified and identify the specific ITAAC used for these verifications.

References:

MHI's Response to US-APWR DCD RAI No. 287-2041; MHI Ref: UAP-HF-09223;Dated May 8, 2009; ML091320436.

MHI's Response to US-APWR DCD RAI No. 287-2041; MHI Ref: UAP-HF-09244;Dated May 21, 2009; ML091480481.

ANSWER:

As described in Section 14.3 in US-APWR DCD Revision 2 identifies the key designfeatures which are based on SRP 14.3 guidance. SRP 14.3 does not identify SeismicCategory II as criteria for safety significant design features. In addition SRP 14.3 does notrequire a generic "seismic I1" ITAAC. However, some non-safety SSCs were determined torequire an ITAAC to verify the as-built design is seismic II on an inspection of a report or a"basic walk down" inspection. An example where a non-safety SSC is verified as seismic IIis identified in Tier 1 section 2.7.6.4, Light Load Handling System, Table 2.7.6.4-2, ITAAC2B.

3.2.2-12

Impact on DCD


Impact on COLA


Impact on PRA


3.2.2-13


7/21/2010



Docket No. 52-021




DATE OF RAI ISSUE: 5/10/2010


The response to RAI 276-2043, question 03.02.02-8, referenced the MHI design completion

plans in their letter dated July 14, 2008. Other than design specifications and stress reports,the response did not identify any other design basis information on quality group

classification. Clarify if any additional design basis documents will be available for audit to

establish the basis for the individual quality group classifications to enable theclassifications to be validated. For example, supporting design basis documents thatsupplement the design specifications and can be used to verify the safety function forindividual classifications may include documents such as a "Q" list, detailed P&IDs, system

summary documents, a RTNSS requirements document and procurement specifications.

Reference: MHI's Response to US-APWR DCD RAI No. 276-2043; MHI Ref: UAP-HF-09232; Dated May 8, 2009; ML091320435.

ANSWER:

MHI agrees to make additional documents used to establish the basis for quality groupdesignation for individual SSC's available for audit by the NRC so that the classifications

can be validated. Additional documents should include the "Q-Iist" (or its equivalent),detailed P&IDs, system specifications, and equipment procurement specifications for thoseSSC's within the scope of the DCD.

Impact on DCD


3.2.2-14

Impact on COLA


Impact on PRA


3.2.2-15

Attachment 1

US-APWR DCD Chapter 1 Mark-up

Response to RAI No.580-4584, Revision2

1.INTRODUCTION AND GENERALDESCRIPTION OF THE PLANT

US-APWR Design Control Document

Table 1.8-2 Compilation of All Combined License Applicant Itemsfor Chapters 1-19(sheet 3 of 44)

RAINo.580-4584

COL ITEM NO. COL ITEM

COL 3.2(4) The COL Applicant is to identify the site-specific, safety-relatedsystems and components that are designed to withstand theeffects of earthquakes without loss of capability to perform theirsafety function; and those site-specific, safety-related fluidsystems or portions thereof, as well as the applicable industrycodes and standards for pressure-retaining components.

COL 3.2(5) The COL Applicant is to identify the equipment class and seismiccategory of the site-specific, safety-related and non safety-relatedfluid systems, components (including pressure retaining), andequipment as well as the applicable industry codes andstandards.

COL 3.2(6) The COL Applicant is to apply DCD methods of equipmentclassification and seismic categorization of risk-significant, non-safety related SSCs based on their safety role assumed in thePRA and treatment by the D-ORAP.

COL 3.3(1) The COL Applicant is responsible for verifying the site-specificbasic wind speed is enveloped by the determinations in thissection.

COL 3.3(2) These requirements also apply to seismic category I structuresprovided by the COL Applicant. Similarly, it is the responsibility ofthe COL Applicant to establish the methods for qualification oftornado effects to preclude damage to safety-related SSCs.

COL 3.3(3) It is the responsibility of the COL Applicant to assure that site-specific structures and components not designed for tornadoloads will not impact either the function or integrity of adjacentsafety-related SSCs, or generate missiles having more severeeffects than those discussed in Subsection 3.5. 1.4.

COL 3.3(4) The COL Applicant is to provide the wind load design method andimportance factor for site-specific category I and category IIbuildings and structures.

COL 3.3(5) The COL Applicant is to note the vented and unventedrequirements of this subsection to the site-specific category Ibuildings and structures.

COL 3.4(1) The COL Applicant is to address the site-specific design of plantgrading and drainage.

Tier 2 1.8-7 Revision 2

Attachment 2


Response to RAI No.580-4584, Revision2

3. DESIGN OF STRUCTURES,SYSTEMS, COMPONENTS, AND EQUIPMENT

US-APWR Design Control Document

RWMS, but are part of systems or portions of systems that contain or may containradioactive material.

Equipment Class 4 SSCs are classified as NS or seismic category I1. The codes andstandards for NRC Quality Group D are applied as follows:

RAINo.580-4584

" Pressure Vessels

" Piping

" Pumps

ASME Code, Section VIII, Division 1 (Reference 3.2-19)ASME B31.1 (Reference 3.2-20)

Manufacturers' standards

* Valves ASME B31.1 (Reference 3.2-20)

* Atmospheric Storage Tanks

* 0-15 psig Storage Tanks

API-650 (Reference 3.2-21), AWMA D-100(Reference 3.2-22), orASME B96.1(Reference 3.2-23)API-620 (Reference 3.2-24)

- Supports Manufacturers' standards

3.2.2.5 Other Equipment Classes

Equipment Class 5

Equipment Class 5 is assigned to non-safety related components that are not part of theRWMS and not within the purview of RG 1.26 (Reference 3.2-13). Equipment Class 5 isalso assigned to components that are listed as "risk-significant, non-safety related" basedon the seismic event in Section 17.4.1nadditionthis equipment class is also assigned tonon-safety related structures and structural components, instrumentation, controls, andelectrical components.

Equipment Class 5 SSCs are classified NS or seismic Category II. Seismic Category IISSCs meet the pertinent QA requirements of 10 CFR 50, Appendix B. Codes andstandards, as defined in the design bases, are applied to Equipment Class 5 components.

The COL Applicant is to apply DCD methods of equipment classification and seismiccategorization of risk-significant non-safety related SSCs based on their safety roleassumed in the PRA and treatment by the D-RAP."

Equipment Class 6Equipment Class 6 is assigned to the components of the RWMS and a part of SGBDSwhich cover outside the containment isolation valves except for class 3 components.

Tier 2 3.2-10 Revision 2Tier 2 3.2-10 Revision 2

3. DESIGN OF STRUCTURES, US-APWR Design Control DocumentSYSTEMS, COMPONENTS, AND EQUIPMENT

COL 3.2(5) The COL Applicant is to identify the equipment class and seismic category of the site- RAIspecific, safety-related and non safetY-relatedfluid systems, components (including pressw No.580-retaining), and equipment as well as the applicable industry codes and standards. 4584

COL 3.2(6) The COL Applicant is to aeplv DCD methods ofeguipment classification and seismiccategorization ofrisk-significant non-safety related SSCs based on their safety roleassumed in the PRA and treatment by the D-RAP

9.1.1 References

3.2-1 Definitions, Domestic Licensing of Production and Utilization Facilities, Energy. Title 10,Code of Federal Regulations, Part 50.2, U.S. Nuclear Regulatory Commission,Washington, DC.

3.2-2 Desigqn Objectives for Equipment to Control Releases of Radioactive Material inEffluents-Nuclear Power Reactors, Domestic Licensing of Production and UtilizationFacilities, Energy. Title 10, Code of Federal Regulations, Part 50.34(a)(1), U.S.Nuclear Regulatory Commission, Washington, DC.

3.2-3 Determination of Exclusion area, Low Population Zone, and Population CenterDistance, Reactor Site Criteria, Energy. Title 10, Code of Federal Regulations, Part100.11, U.S. Nuclear Regulatory Commission, Washington, DC.

3.2-4 General Design Criteria for Nuclear Power Plants, Domestic Licensing of Productionand Utilization Facilities, Energy. Title 10, Code of Federal Regulations, Part 50,Appendix A, U.S. Nuclear Regulatory Commission, Washington, DC.

3.2-5 Seismic Desiqn Classification. Regulatory Guide 1.29, Rev. 4, U.S. NuclearRegulatory Commission, Washington, DC, March 2007.

3.2-6 Earthquake Engineerinq Criteria for Nuclear Power Plants, Domestic Licensing ofProduction and Utilization Facilities, Energy. Title 10, Code of Federal Regulations,Part 50, Appendix S, U.S. Nuclear Regulatory Commission, Washington, DC.

3.2-7 Geologic and Seismic Siting Criteria, Reactor Site Criteria, Energy. Title 10, Code ofFederal Regulations, Part 100.23, U.S. Nuclear Regulatory Commission, Washington,DC.

3.2-8 Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,Domestic Licensinq of Production and Utilization Facilities, Energy. Title 10, Code ofFederal Regulations, Part 50, Appendix B.

3.2-9 Instrument Sensing Lines. Regulatory Guide 1.151, U.S. Nuclear RegulatoryCommission, Washington, DC, July 1983.

Tier 2 3.2-12

Revision 2Tier 2 3.2-12 Revision 2

Attachment 3


Response to RAI No.580-4584, Revision 2

0l AI YII IAIDV .•V_•TI::MQ I I_•ADXR:) I'lai n f"_nftrl nr•-" ma•nt

Two 100% capacity strainers are located in each ESWP discharge line. The differential RAI

pressure across the operating strainer is monitored. When the predetermined high No.580-4584differential set pressure across the strainer is reached an alarm is sent to the MCR; theclogged strainer is isolated by first shutting off the ESWP and them closing the strainerisolation valves. The standby strainer is then placed in service by manually opening thestrainer isolation valves. The clogged strainer cartridge will be manually replaced. Thesestrainers filter out most of the debris and thus provide adequate protection for ESWScomponents.

One 100% capacity self-cleaning type strainer is located upstream of each CCW HX.The strainer is continuously blown down at a rate of 500 gpm to prevent buildup ofimpurities and clogging of the CCW HXs. The blowdown water is dischargeddownstream of the CCW HXs. No strainer is provided for essential chller unit coolerssince filtration is provided by the ESWP discharge pipe strainers and additional filtering isnot deemed necessary.

9.2.1.2.2.3 CCW HX

Four 50% capacity plate type HXs, one per train, are provided. A detailed description ofthe HXs is discussed in Subsection 9.2.2.

9.2.1.2.2.4 Essential Chiller Units

Four 50% capacity chiller units, one per train, are provided. A detailed description of theessential chiller units is given in Subsection 9.2.7.

9.2.1.2.2.5 Piping

Carbon steel piping designed, fabricated, installed and tested in accordance with ASMESection III, Class 3 requirements, is used for the safety-related portion of the ESWS.Piping is arranged to permit access for inspection. Underground piping is epexyDolvethylene lined carbon steel and placed in trenches. Manholes are provided forperiodic piping inspection.

9.2.1.2.2.6 Valves

The water in the ESWS does not normally contain radioactivity and, therefore, specialprovisions against the leakage to the atmosphere are not necessary. Isolation valves areprovided upstream and downstream of each component to facilitate its removal fromservice.

The motor operated valve is provided at the discharge of each pump. The starting logicof the ESWP interlocks the motor operated valve with the pump operation. The doseddischarge valve opens after starting the ESWP. This feature minimizes transient effectsthat may occur as the water sweeps out air that maybe present in the system. If themotive power of the valve is lost, the valve maintains its open position.

Each CCW HX is provided with two separate locked close isolation valves and pipingaround the heat exchanger for back flushing. One valve is located in the piping running

Tier 2 9.2-1

Revision 2

Tier 2 9.2-1 Revision 2

Documents

MHI's Responses to US-APWR DCD RAI No. 580-4584, SRP ...MHI Ref: UAP-HF-10215 Subject: MHI's Responses to US-APWR DCD RAI No. 580-4584 Reference: 1) "Request for Additional Information