ML15112A232
| ML15112A232 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/27/1998 |
| From: | Labarge D NRC (Affiliation Not Assigned) |
| To: | Mccollum W DUKE POWER CO. |
| References | |
| GL-97-01, GL-97-1, TAC-M98579, TAC-M98580, TAC-M98581, NUDOCS 9809010381 | |
| Download: ML15112A232 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION t
WASHINGTON, D.C. 20555-0001 August 27, 1998 Mr. W. R. McCollum Vice President, Oconee Site Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION: RESPONSES TO GENERIC LETTER (GL) 97-01, "DEGRADATION OF CRDM/CEDM NOZZLE AND OTHER VESSEL CLOSURE HEAD PENETRATIONS" FOR THE OCONEE NUCLEAR STATION UNITS 1, 2, AND 3 (TAC NOS. M98579, M98580, AND M98581)
Dear Mr. McCollum:
On April 1, 1997, the staff issued Generic Letter (GL) 97-01, "Degradation of CRDM/CEDM
[Control Rod Drive Mechanism/Control Element Drive Mechanism] Nozzle and other Vessel Closure Head Penetrations," to the industry requesting, in part, that addressees provide a description of the plans to inspect the vessel head penetration nozzles (VHPs) at their respective pressurized water reactor (PWR) designed plants. With respect to the issuance. of the GL, the staff required the addressees to submit an initial response within 30 days of issuance informing the staff of the intent to comply with the requested information and a follow up response within 120 days of issuance containing the technical details to the staffs information requests. In the discussion section of the GL, the staff stated that "individual licensees may wish to determine their inspection activities based on an integrated industry inspection program...," and indicated that it did not object to individual PWR licensees basing their inspection activities on an integrated industry inspection program.
As a result, the Babcock and Wilcox Owners Group (B&WOG) determined that it was appropriate for its members to develop a cooperative integrated inspection program in response to GL 97-01. The B&WOG program is documented in Topical Report BAW-2301, "Degradation of CRDM/CEDM Nozzle and Other Vessel Closure Head Penetrations," which was prepared by
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Framatome Technologies Incorporated on behalf of the B&WOG and the following B&WOG member utilities and plants:
General Public Utilities - Three Mile Island Unit 1 Duke Energy Corporation - Oconee Nuclear Station Units 1, 2, and 3 Entergy Operations, Inc. - Arkansas Nuclear One Unit 1 Centerior Energy Corp. - Davis Besse Nuclear Plant Florida Power Corporation - Crystal River Unit 3 The B&WOG submitted its integrated program and Topical Report BAW-2301 to the staff on July 25, 1997.
The staff has determined by your letters dated April 28 and July 2, 1997, that you were a member of the B&WOG and a participant in the B&WOG integrated program that was developed to address the staff's requests in GL 97-01. In your letters of April 28 and July 2, 9809010381 980827 3
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W. R. McCollum
-2 1997, you also indicated that the information in Topical Report BAW-2301 is applicable with respect to the assessment of VHP nozzles at the Oconee Nuclear Station Units 1, 2, and 3.
The staff has reviewed your responses to GL 97-01 dated April 28 and July 2, 1997, and requires further information to complete its review of the responses as they relate to the B&WOG's integrated program for assessing VHP nozzles at B&WOG member plants, and to the contents of Topical Report BAW-2301. The enclosure to this letter forwards the staffs inquiries in the form of a request for additional information (RAI). The staff requests that you respond to the RAI by November 20, 1998. It should be noted that similar staff requests have been issued to the other B&WOG member utilities. The staff encourages you to continue to address these inquiries in integrated fashion with the B&WOG; however, the staff also requests that you identify any deviations from the B&WOG's integrated program that may be specific to your facilities.
Sincerely, David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - I/Il Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page
W.
August 27, 1998 1997, you also indicated that the information in Topical Report BAW-2301 is applicable with respect to the assessment of VHP nozzles at the Oconee Nuclear Station Units 1, 2, and 3.
The staff has reviewed your responses to GL 97-01 dated April 28 and July 2, 1997, and requires further information to complete its review of the responses as they relate to the B&WOG's integrated program for assessing VHP nozzles at B&WOG member plants, and to the contents of Topical Report BAW-2301. The enclosure to this letter forwards the staffs inquiries in the form of a request for additional information (RAI). The staff requests that you respond to the RAI by November 20, 1998. It should be noted that similar staff requests have been issued to the other B&WOG member utilities. The staff encourages you to continue to address these inquiries in integrated fashion with the B&WOG; however, the staff also requests that you identify any deviations from the B&WOG's integrated program that may be specific to your facilities.
Sincerely, ORIGINAL SIGNED BY:
David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - II Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page Distribution:
COgle, RII Docket File JHarold PUBLIC OGC PD 11-2 Rdg.
ACRS JZwolinski LPlisco, RII Document Name: G:\\OCONEE\\OCO98579.RAI To receive a copy of this document, indicate in the box:
"C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No copy OFFICE PDI -
P P
NAME DL e:cn LBerry JHarold Ber w
DATE
/98
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'//2/98 OFFICIAL RECORD COPY
Oconee Nuclear Station cc:
Mr. Paul R. Newton Mr. J. E. Burchfield Legal Department (PBO5E)
Compliance Manager Duke Energy Corporation Duke Energy Corporation 422 South Church Street Oconee Nuclear Site Charlotte, North Carolina 28201-1006 P. 0. Box 1439 Seneca, South Carolina 29679 J. Michael McGarry, Ill, Esquire Winston and Strawn Ms. Karen E. Long 1400 L Street, NW.
Assistant Attorney General Washington, DC 20005 North Carolina Department of Justice Mr. Robert B. Borsum P. 0. Box 629 Framatome Technologies Raleigh, North Carolina 27602 Suite 525 1700 Rockville Pike L. A. Keller Rockville, Maryland 20852-1631 Manager - Nuclear Regulatory Licensing Manager, LIS Duke Energy Corporation NUS Corporation 526 South Church Street 2650 McCormick Drive, 3rd Floor Charlotte, North Carolina 28201-1006 Clearwater, Florida 34619-1035 Mr. Richard M. Fry, Director Senior Resident Inspector Division of Radiation Protection U. S. Nuclear Regulatory North Carolina Department of Commission Environment, Health, and 7812B Rochester Highway Natural Resources Seneca, South Carolina 29672 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Regional Administrator, Region II U. S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, Georgia 30303 Virgil R. Autry, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201-1708 County Supervisor of Oconee County Walhalla, South Carolina 29621
Request for Additional Information for Utilities Generic Letter (GL) 97-01, "Degradation of CRDM/CEDM Nozzle and Other Vessel Closure Head Penetrations" The methodology developed by Framatome Technology Incorporated (FTI) for predicting the susceptibility of vessel head penetration nozzles in Babcock and Wilcox Owners Group (B&WOG) plant designs is provided in Appendix B to the report, "Description of CRDM [Control Rod Drive Mechanism] Nozzle PWSCC [primary water stress-corrosion cracking] Inspection and Repair Strategic Evaluation Model." The CRDM Nozzle PWSCC Inspection and Repair Strategic Evaluation (CIRSE) methodology for crack initiation is dependent on the calculation of a Relative Susceptibility Factor, which, in part, is a function of a number of multiplicative adjustment factors (e.g., the material factors, fabrication factors, and water chemistry factors).
FTI has assumed that there is little variability in the alloying chemistries and microstructures of the heats used to fabricate the Babcock and Wilcox (B&W) CRDM penetration and.
thermocouple nozzles, and has therefore set the values for these multiplicative adjustment factors to a value of 1.0. This simplifies the CIRSE crack initiation model to one that is simply based on the applied nozzle stresses and nozzle operating temperatures. The approach taken does not appear to be consistent with the ranges of data provided in Table 1 of the report, "CRDM Nozzle Heats at B&W-Design Plant," which provides the yield strengths, ultimate tensile strengths, and carbon contents for the B&W CRDM penetration nozzle material heats.
The data in Table 1 of the report imply that there may be some variability in the chemistries and microstructures of the Alloy 600 material heats used to fabricate. the B&W CRDM penetration nozzles.
Topical Report BAW-2301 also provides the B&WOG inspection schedule and scope for vessel head penetration (VHP) nozzles in B&W designed plants. In this section, the B&WOG indicated that the schedule for VHP nozzle inspections was developed based on the susceptibility assessments of the B&W CRDM penetration nozzles and thermocouple nozzle heats. The specific results of the CRDM penetration nozzle susceptibility rankings for the B&WOG plants were not provided in the report; however, the B&WOG has indicated that additional inspections of the B&W fabricated CRDM penetration nozzles have been scheduled for the 1999 refueling outages (RFOs) of the Oconee Nuclear Station Unit 2 (ONS-2) and at Crystal River Unit 3 (CR-3) plants. In addition, FTI has also indicated that additional inspections of the thermocouple nozzles at Three Mile Island Unit 1 (TMI-1) and ONS Unit 1 (ONS-1) are tentatively scheduled for the year 2001. Therefore, with respect to the design of the CIRSE crack initiation and crack growth models, the susceptibility rankings for VHPs in B&W designed plants, the proposed CRDM nozzle inspections at ONS-2 and CR-3, and the postulated inspections of the instrumentation nozzles at TMI-1 and ONS-1, the staff requests the following information:
- 1.
Provide a description of how the various product forms, material specifications, and heat treatments used to fabricate each CRDM penetration nozzle at the B&WOG member utilities are handled in the CIRSE model.
Enclosure
-2
- 2.
Provide any additional information, if available, regarding how the model will be refined to allow the input of plant-specific inspection data into the model's analysis methodology.
- 3.
Describe how FTI's crack initiation and crack growth models for assessing postulated flaws in VHP nozzles were benchmarked, and provide a list and discussion of the standards the models were benchmarked against.
- 4.
Provide the latest CIRSE model susceptibility rankings of B&W designed facilities based on the CIRSE model analysis results compiled from the analyses of the CRDM and instrumentation nozzles at the facilities.
- 5.
Compare the overall susceptibility rankings of the thermocouple nozzles at ONS-1 to that of the plants with the most susceptibly ranked CRDM penetration nozzles. Based on this assessment, indicate whether the thermocouple nozzles at ONS-1 will be inspected during the year 2001 refueling outage. If it is determined that the thermocouple nozzles will not be inspected, provide the basis for omitting the inspections of the thermocouple nozzles in the year 2001.