ML15111A317
| ML15111A317 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/21/2015 |
| From: | Mozafari B Plant Licensing Branch III |
| To: | Mathews M Exelon Corp |
| References | |
| TAC MF3352, TAC MF3353 | |
| Download: ML15111A317 (5) | |
Text
1 NRR-PMDAPEm Resource From:
Mozafari, Brenda Sent:
Tuesday, April 21, 2015 12:48 PM To:
Mitchel.Mathews@exeloncorp.com; Simpson, Patrick R.:(GenCo-Nuc)
(patrick.simpson@exeloncorp.com)
Cc:
Tate, Travis
Subject:
FW: DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING DRESDEN Relief I4-17 Attachments:
2nd Draft April RAI MF3352 MF 3353.docx MITCH and PAT, Regarding the electronic RAI for the 10-year ISI Relief I4-17 (Previously Draft of a Draft awaiting BC concurrence.) Herein are the Draft RAI questions related to Dresdens LAR. RAI Questions are attached.
Subject:
DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING DRESDEN Relief I4-17
- Mitch,
SUBJECT:
DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING THE DRESDEN NUCLEAR POWER STATION, UNITS 2, AND 3 FOURTH 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN REQUESTS FOR RELIEF (TAC NOS. MF3352 AND MF3353)
- Mitch, The NRC staff has reviewed and evaluated the information provided by, Exelon Generation Company, LLC (the licensee) in its letter dated October 16, 2014. The licensee submitted additional information for Request for Relief I4-17 from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI for Dresden Nuclear Power Station, Units 2 and 3 (DNPS 2 and 3). The requests for relief apply to the fourth 10-year inservice inspection interval, in which the licensee adopted the 1995 Edition through the 1996 Addenda of ASME Code Section XI as the code of record.
The NRC staff's request for additional information (RAI) or to clarify RAI responses is contained in the enclosed Draft RAI. Your response is requested within 30 days of the date of this email and should contain the verbatim questions of the Draft RAI. I will send the ADAMS accession number of the emailed RAI for you to reference when you respond to the Draft RAI. When your response is received I will provide an email to indicate the RAI is final which will be thus documented in ADAMS.
Brenda L. Mozafari Senior Project Manager, NRR/DORL U.S. Nuclear Regulatory Commission Dresden 2/3 and Quad Cities 1/2 301-415-2020 email: brenda.mozafari@nrc.gov
Hearing Identifier:
NRR_PMDA Email Number:
2016 Mail Envelope Properties (Brenda.Mozafari@nrc.gov20150421124800)
Subject:
FW: DRAFT REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING DRESDEN Relief I4-17 Sent Date:
4/21/2015 12:48:22 PM Received Date:
4/21/2015 12:48:00 PM From:
Mozafari, Brenda Created By:
Brenda.Mozafari@nrc.gov Recipients:
"Tate, Travis" <Travis.Tate@nrc.gov>
Tracking Status: None "Mitchel.Mathews@exeloncorp.com" <Mitchel.Mathews@exeloncorp.com>
Tracking Status: None "Simpson, Patrick R.:(GenCo-Nuc) (patrick.simpson@exeloncorp.com)"
<patrick.simpson@exeloncorp.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 1968 4/21/2015 12:48:00 PM 2nd Draft April RAI MF3352 MF 3353.docx 46905 Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received:
Enclosure SECONDREQUESTFORADDITIONALINFORMATION ONTHEFOURTHTENYEAR10-YEARINSERVICEINSPECTIONINTERVALREQUEST FORRELIEFI4R-17 FOR EXELONGENERATIONCOMPANY,LLC.DRESDENNUCLEARP OWERSTATION,UNITS2AND3 DOCKETNUMBERS: 50-237AND50-249
- 1. SCOPE ByletterdatedDecember30,2013,(AgencywideDocumentsAccess&ManagementSystem (ADAMS)AccessionNumberML13364A361),thelicensee,ExelonGenerationCompany,LLC,subm ittedRequestforReliefI4R-17fromtherequirementsoftheAmericanSociety of MechanicalEngineers(ASME)BoilerandPressureVesselCode,SectionXI,Rulesfor InserviceInspectionofNuclearPowerPlantComponentsforDresdenNuclearPowerStation, Units2and3(DNPS2 and3). Therequestforreliefappliestothefourth10-yearinservice inspection(ISI)interval,inwhichthelicenseeadoptedthe1995Editionthroughthe1996 AddendaofASMECodeSectionXIasthecodeofrecord. TheU.S. Nuclear Regulatory Commission (NRC)requestedthatthelicensee providefurtherinformation,andthelicenseeprovidedaresponsetotheRequestforAdditional Information(RAI)inaletterdatedOctober16,2014(ADAMSAccessionNumberML14293A255).
However,certainrequestedinformationwasnotprovidedand/orrequiresclarificationinorderfor thestafftocompletetheevaluationofthelicenseesrequest. Pleasesubmitanswerstothe followingquestions.
- 2. REQUESTFORADDITIONALINFORMATION 2.1 Request for Relief I4R-17, Examination Category B-A, Item B1.40, Pressure Retaining Welds in Vessels in Reactor Vessels, DNPS 2 and 3
- 1) The licensee states that, for Unit 2, only 41.7 percent coverage was obtained on the top head-to-flange weld. The drawing submitted in the RAI response appears to support the claim that examinations may only be conducted from the head side of the weld due to geometry. However, it is stated that Unit 3 was able to get 72 percent volumetric coverage, while the drawing shows the top head-to-flange welds at DNPS 2 and 3 to be geometrically similar. Please clarify why the licensee was able to obtain a marked increase in volumetric coverage on DNPS 3.
- 2) In Attachment 2 of the licensees RAI response, it appears that the top head-to-flange weld drawing on page 333 has different coverage values than the coverage calculation sheet on page 334. Please verify the information provided for the Unit 2 top head-to-flange weld in the RAI response and provide a corrected coverage sketch or coverage calculation sheet, whichever one is currently incorrect.
2.2 Request for Relief I4R-17, Examination Category B-D, Items B3.90 and B3.100, Full Penetration Welded Nozzles in Vessels, DNPS 2 and 3
- 1) Please provide a coverage plot for Unit 2 RPV nozzle inside radius Weld 2/1/RPVSHELL/N5B-1 as there was no sketch provided in the licensees RAI response.
- 2) Please verify that the base materials near the inside surface of the weld joints, particularly the high regions of stress, where examined in the B-D, Items B3.90 welds in DNPS 2 and 3.
2.3 Request for Relief I4R-17, Part G, Examination Category R-A, Items R1.11 and R1.20, Risk Informed Piping Examinations, DNPS 2 and 3 Table 2.3.1-Examination Category R-A (Unit 2)
Code Item Weld ID Weld Type Coverage Obtained R1.11 2/1/1001A-16/16-11 Tee-to-Pipe 36.0 %
R1.11 2/1/1001B-16/16-2 Flange-to-Pipe 85.0 %
R1.11 2/1/1005B-14/14-7 Valve-to-Pipe 50.0 %
R1.20 2/1/1403-10/W-103 Valve-to-Pipe 81.0 %
R1.20 2/1/1404-10/W-112 Valve-to-Pipe 85.0 %
Table 2.3.2-Examination Category R-A (Unit 3)
Code Item Weld ID Weld Type Coverage Obtained R1.11 3/2/3204B-18/18-1 Valve-to-Tee 78.9 %
R1.20 3/1/1302-14/14-9(A)
Flange-to-Pipe 50.0%
Provide coverage plots for all RI-ISI welds listed in Tables 2.3.1 and 2.3.2 above. From the coverage sketches provided in the licensees RAI response, it is difficult for the staff to determine how the licensee determined the coverage percentages on the welds in Table 2.3.1 and 2.3.2 as the supplied diagrams are very similar to each other yet yield very different coverage percentages.
2.4 Request for Relief I4R-17, Examination Category C-B, Item C2.21, Pressure Retaining Nozzle Welds in Class 2 Vessels, DNPS 2 and 3 Table 2.4.1-Examination Category C-B (Unit 2)
Code Item Weld ID Weld Type Coverage Obtained C2.21 2/2/1302A-12/12-9 ISO Condenser Nozzle Weld 50.0 %
C2.21 2/2/1302B-12/12-8 ISO Condenser Nozzle Weld 50.0 %
C2.21 2/2/1303A-8/8-9 ISO Condenser Nozzle Weld 50.0 %
C2.21 2/2/1203B-8/8-8 ISO Condenser Nozzle Weld 50.0 %
Table 2.4.2-Examination Category C-B (Unit 3)
Code Item Weld ID Weld Type Coverage Obtained C2.21 3/2/1302A-12/12-8 ISO Condenser Nozzle Weld 37.8 %
C2.21 3/2/1302B-12/12-9 ISO Condenser Nozzle Weld 37.8 %