ML060030228

Request for Additional Information Regarding the 15-Day and 90-Day (Including W*) Steam Generator Tube Inservice Inspection Reports for the End-Of-Cycle 13 Refueling Outage in 2005

ML060030228
Person / Time
Site:	Sequoyah
Issue date:	01/13/2006
From:	Pickett D Plant Licensing Branch III-2
To:	Singer K Tennessee Valley Authority
Pickett , NRR/DLPM, 415-1364
References
TAC MC8118
Download: ML060030228 (4)

Text

January 13, 2006Mr. Karl W. SingerChief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNIT 2 - REQUEST FOR ADDITIONALINFORMATION REGARDING THE 15-DAY AND 90-DAY STEAM GENERATOR TUBE INSERVICE INSPECTION REPORTS FOR THE END-OF-CYCLE 13 REFUELING OUTAGE IN 2005 (TAC NO. MC8118)

Dear Mr. Singer:

By letter dated May 31, 2005 (ADAMS No. ML051600187), Tennessee Valley Authority (TVA,the licensee) submitted the 15-day steam generator (SG) plugging report in accordance with Technical Specification 4.4.5.5.a for the Sequoyah Nuclear Plant, Unit 2. By letter datedAugust 15, 2005 (ADAMS No. ML052340503), TVA submitted the 90-day SG voltage-based alternate repair criteria and W* (WEXTEX-expanded region alternate tube plugging criteria) report in accordance with License Condition 2.C.(8)(b). In addition to these reports, the Nuclear Regulatory Commission staff summarized additional information concerning the Unit 2 2005 SG tube inspection in a letter dated June 7, 2005 (ADAMS No. ML051810694).

In order for the staff to complete its review of the reports, we request that the licensee provide responses to the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you intend to respond to this RAI within 60 days of receipt of this letter.Sincerely,/RA/Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-328

Enclosure:

As stated cc w/encl: See next page January 13, 2006Mr. Karl W. SingerChief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNIT 2 - REQUEST FOR ADDITIONALINFORMATION REGARDING THE 15-DAY AND 90-DAY STEAM GENERATOR TUBE INSERVICE INSPECTION REPORTS FOR THE END-OF-CYCLE 13 REFUELING OUTAGE IN 2005 (TAC NO. MC8118)

Dear Mr. Singer:

By letter dated May 31, 2005 (ADAMS No. ML051600187), Tennessee Valley Authority (TVA,the licensee) submitted the 15-day steam generator (SG) plugging report in accordance with Technical Specification 4.4.5.5.a for the Sequoyah Nuclear Plant, Unit 2. By letter datedAugust 15, 2005 (ADAMS No. ML052340503), TVA submitted the 90-day SG voltage-based alternate repair criteria and W* (WEXTEX-expanded region alternate tube plugging criteria) report in accordance with License Condition 2.C.(8)(b). In addition to these reports, the Nuclear Regulatory Commission staff summarized additional information concerning the Unit 2 2005 SG tube inspection in a letter dated June 7, 2005 (ADAMS No. ML051810694).In order for the staff to complete its review of the reports, we request that the licensee provideresponses to the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you intend to respond to this RAI within 60 days of receipt of this letter.Sincerely, Douglas V. Pickett, Senior Project ManagerPlant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-328

Enclosure:

As stated cc w/encl: See next page Distribution:PUBLICRidsOgcRpLPL2-2 r/fRidsNrrDorlLpldRidsNrrPMDPickettLMillerAHiserRidsRgn2MailCenter (SCahill)RidsAcrsAcnwMailCenterRSolaLLundADAMS Accession No.: ML060030228OFFICENRR/LPL2-2/PMNRR/LPL2-2/LAEMCB/SCNRR/LPL2-2/BCNAMEDPickett:eoBClayton forRSola LLundBy memo datedMMarshallDATE1/9/06 1/6/06 10/07/051/13/06 EnclosureOFFICIAL RECORD COPYREQUEST FOR ADDITIONAL INFORMATIONSEQUOYAH UNIT 2 END-OF-CYCLE 13 15-DAY AND 90-DAY (INCLUDING W*)STEAM GENERATOR INSERVICE INSPECTION REPORTSDOCKET NO. 50-3281.On Page 4-6, it was stated that only one indication was 2-volts or greater out of the 302(sizing sample) indications at the End-Of-Cycle (EOC) 13 that were tested with a worn probe during the EOC 12 inspection. With this information, you concluded that probe wear has no significant effect on the population of indications. In addition, it was stated that out of 365 (population sample) indications at the EOC 13, only 81 were inspectedwith a worn probe during the EOC 12 inspection. You further concluded that this information indicated that tubes inspected with worn probes do not contain a largernumber of new indications. The basis for these statements is not clear to the NRC staff, therefore, please provide justification for these statements. This justification should include a comparison of the percentage of new indications atthe EOC 13 that were inspected with a worn probe during the EOC 12 inspection to thepercentage of new indications that were inspected with a good probe during the EOC 12inspection. In addition, please compare the percentage of new indications greater than or equal to 0.5-volts at the EOC 13 that were inspected with a worn probe during theEOC 12 inspection to the percentage of new indications greater than or equal to 0.5-volts at EOC 13 that were inspected with a good probe during the EOC 12inspection. If there are significant differences, please provide an assessment of the adequacy of the probe wear criteria and its impact on your operational assessment for EOC 14. A value of 0.5-volts was chosen to be consistent with the NRC staff's approvalof the alternate probe wear criterion (refer to NRC letter to the Nuclear Energy Institutedated February 9, 1996).2.In Section 6.4 of Enclosure 1 to your August 15, 2005, letter, it was indicated that theEOC 14 voltage distribution (using both the Cycle 12 and Cycle 13 growth rates) are shown in Table 6-2 and in Figures 6-1 through Figure 6-4. In reviewing the table and figures only one voltage distribution was provided for each steam generator.

Please clarify whether the tables and graphs provided were determined using the Cycle 12 or Cycle 13 voltage growth rate distribution.In addition, Section 6.4 indicates that the voltage distributions predicted using bothgrowth rates are similar, however, the predictions using the Cycle 13 growth rates were populated with somewhat greater frequency in the lower voltages and with higher tail-end voltages. Since the most limiting voltage growth rate distribution is the one that results in the highest projected probability of burst and leakage, discuss how it wasdetermined that the Cycle 12 growth rate distribution was the most limiting. The NRCstaff notes that sometimes the higher tail-end voltages can result in more limiting probability of burst or leakage estimates (i.e., the largest voltage indication may have asignificant effect on the leakage and burst calculations depending on the distribution of Enclosureindications).

Mr. Karl W. SingerSEQUOYAH NUCLEAR PLANTTennessee Valley Authority cc: Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, General ManagerNuclear Engineering Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Robert J. Beecken, Vice PresidentNuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Randy DouetSite Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000General CounselTennessee Valley Authority ET 11A 400 West Summit Hill DriveKnoxville, TN 37902Mr. John C. Fornicola, ManagerNuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Glenn W. Morris, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801Mr. Paul L. Pace, ManagerLicensing and Industry Affairs ATTN: Mr. James D. Smith Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000Mr. David A. Kulisek, Plant ManagerSequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000Senior Resident InspectorSequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379Mr. Lawrence E. Nanney, DirectorDivision of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532County MayorHamilton County Courthouse Chattanooga, TN 37402-2801Ms. Ann P. Harris341 Swing Loop Road Rockwood, Tennessee 37854