ML20199F369
| ML20199F369 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 01/11/1999 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-01, GL-97-1, NEL-99-0003, NEL-99-3, NUDOCS 9901210303 | |
| Download: ML20199F369 (4) | |
Text
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Dave Morzy Southtrn Nuclear L %ce President i Op: rating Crmpary se
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Fartey Project
, P.O. Box 1295 l
Birmingham, Alabama 35201 Tel 205.992.5131 i
k SOUTHERN h i
COMPANY January-11, 1999 Energyto Serve YourWorir Docket Nos.
50-348 NEI 99-0003 50-364
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- U. S. Nuclear Regulatory Commiscion Atta: Document Cmtrol Desk Washington, D. C. 205550001 Joseph M. Farley Nuclear Plant i
Response to Request for A&htional Information Concermag Genenc Later 97-01, " Degradation of CRDM/CEDM Nozzle and Other Vessel Closure Head Penetrations" ladies and Gentlemen:
l By later dated August 27,1998, the NRC requested additional information (RAI) regardmg i
the response to Generic Letter 97-01, "Degradaten of CRDM/CEDM Nozzle and Other Vessel Closure Head Penetratians," for Farley Nuclear Plant (TNP) - Units 1 and 2. A response to the RAI was requested by November 25,1998. Byletter dated October 29,1998, the response date was revised to January 15,1999.
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'Ihe EPRI Matenals Reliability Project, in cooperation with the PWR Owners Groups, is I
coortimating a generic industry program for the Alloy 600 head F.A kms As part of that program, they have developed a comprehannive industry response to the RAIs sent to FNP and other PWRs. On December 11,1998, NEI subnutted the industry response to the RAIs. 'Ihc Southern Nuclear Ope ating Company (SNC) response to the RAI is cW=~t as part of the 1
- generic industry response. The attachment provides a restatement of the NRC questions and indicates the kratiaan of the SNC responses in the NEI letter.
This letter contains no additional comnutments. Ifyou have any questions, please advise.
Respectfully subnutted, 1
$ f }?lr w Dave Morey EWC/maf: raigl97. doc Attachment I(
. cc:
Mr. L. A. Reyes, Region II Adrainierrator
[
I Mr. J.1. T
-. NRRProject Manager Mr. T. P. Jahaman, FNP Plant Sr. Resident Inspector l
9901210303.990111 l
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se ATTACHMENT FARLEY NUCLEAR PLANT UNITS 1 AND 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION CONCERNING GENERIC LEITER 97-01, " DEGRADATION OF CRDM/CEDM NOZZLE AND OTHER VESSEL CL,OSUP2 HEAD PENETRATIONS" The following responses are based on NEI letter to the NRC, dated December 11,1998.
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I Ouestion:
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- 1. In WCAP-14901, WEC did not provide any conclusions as to what the probabilistic failure model would lead the WOG to conclude with respect to the assessment of primary water stress <:orrosion cracking (PWSCC) in WEC-designed vessel head penetrations.
l-With respect to the probabilistic susceptibility model (e.g., probabilistic failure model) provided in WCAP-14901:
la. Provide the susceptibility rankings compiled for the WOG member plants for l
which WCAP-14901 is applicable. In regard to other WOG member plants to which WCAP-l 14901 is applicable, include the basis for establishing the ranking of your plant relative to the others.
Response
la. See response to Generic Question 4 in Section I of Enclosure 5.
j Ouestion:
j lb. Describe how the probandistic failure model in WCAP-14901 for assessing postulated flaws in the VHP nozzles was tenchmarked, and provide a list and discussion cf the standards the model was benchmarked against.
Response
lb. See response to Generic Question 2 in Section I of Enclosure 5. (Westinghouse l
Model applies.)
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ATTACHMENT l
Ouestion:
Ic. Provide additional information regarding how the probabilistic failure models in WCAP-14901 will be refined to allow the input of plant-specific inspection data into the model's analysis methodology.
Response
Ic. See response to Generic Question 3 in Section I of Enclosure 5. (Westinghouse Model applies.)
l Ouestion:
l Id. Describe how the vanability in product forms, material specifications, and heat j
treatments used to fabricate cach CRDM penetration nozzle at the WOG member utilities are addressed in the probabilistic crack initiation and growth models described or reibrenced in Topical Report WCAP-14901.
Response
Id. See response to Generic Question 1 in Section I of Enclosure 5. (Westinghouse Model applies.)
Ouestion:
- 2. Table 1-2 in WCAP-14901 provides a summary of the key tasks in WEC's VHP nozzle assessment program 'Ihe table indicates that the Tasks for (1) Evaluation of PWSCC Mitigation Methods, (2) Crack Growth Data and Testing, and (3) Crack initiation Characterization Studies have not been completed and are still in progress. In light of the fact that the probabilistic susceptibility models appear to be Wa t in part on PWSCC crack n
initiation and growth estimates, provide your best estimate when these tasks will be completed by WEC, and describe how these activities relate to and will be used to update the probabilistic susceptibility assessment of VHP nozzles at your plant.
Esanenasi
- 2. See response to Generic Question 5 in Section I of Enclosure 5.
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ATTACHMENT Ouestion:
- 3. In the NEl letters of January 29,1998 (Ref.1), and April 1,1998 (Ref. 2), NEI indicated that inspection plans have been developed for the VHP nozzles at the Farley Unit 2 plant in the year 2002, and at the Diablo Canyon Unit 2 plant in the year 2001, respectively.
'Ihe staff has noted that although you have endorsed the probabilistic susceptibility model described in WCAP-14901, Revision 0, other WOG members have endorsed a probabilistic susceptibility rnodel developed by an alternate vendor of choice. The WOG's proposal to inspect the VHP nozzles at the Farley Unit 2 and the Diablo Canyon Unit 2 plants appears to be based upon a composite assessment of the VHP nozzles at all WOG member plants. Verify that such a composite rankmg assessment has been applied to the evaluation of VHP nozzles at your plants. If composite rankings of the VHP nozzles at WOG member plants have been obtained from the composite results of the two models, justify why application of the probabilistic susceptibility model described in WCAP-14901, Revision 0, would yield the same comparable relative rankings of the VHP nozzles for your plant as would application of the alternate probabilistic susceptibility model used by the WOG member plants not subscribing to WCAP-14901, Revision 0. Comment on the susceptibility rankings of the VHP nozzles at the Farley Unit I and Unit 2 plants relative to the susceptibility rankings of the VHP nozzles at other member plants.
Response
- 2. See response to WOG Specific Question 1 of Section II of Enclosure 5.
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