ML20151X172
| ML20151X172 | |
| Person / Time | |
|---|---|
| Issue date: | 09/10/1998 |
| From: | Wen P NRC (Affiliation Not Assigned) |
| To: | Sepp H WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| TAC-MA2086, NUDOCS 9809160297 | |
| Download: ML20151X172 (5) | |
Text
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September 10, 1998 Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering Westinghouse Electric Corporation Mail Stop ECE 4-07A Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR WESTINGHOUSE TOPICAL REPORT WCAP-15063-P, " WESTINGHOUSE IN-REACTOR CREEP MODEL"(TAC No. MA2086)
Dear Mr. Sepp:
By letter dated June 9,1998, Westinghouse submitted topical report WCAP-15063-P for NRC review. The staff has reviewed the report and determined a need for additional information.
The enclosure to this letter identifies the information required. Please address your response to the NRC Document Control Desk.
If you wish to meet with the staff to accelerate the information transfer, the staff would welcome such a meeting at a mutually convenient time. If you have any questions on this matter, I may be contacted by phone,301/415-2832, or by e-mail, pxw@nrc. gov.
Sincerely, Original Signed By]
Peter C. Wen, Project Manager Generic issues and Environmental Projects Branch Office of Nuclear Reactor Regulation
Enclosure:
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September 10, 1998 Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering Westinghouse Electric Corporation Mail Stop ECE 4-07A Post Office Box 355 l
Pittsburgh, Pennsylvania 15230-0355
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR WESTINGHOUSE TOPICAL REPORT WCAP-15063-P, " WESTINGHOUSE IN-REACTOR CREEP MODEL"(TAC No. MA2086)
Dear Mr. Sepp:
By letter dated June 9,1998, Westinghouse submitted topical report WCAP-15063-P for NRC review. The staff has reviewed the report and determined a need for additional information.
The enclosure to this letter identifies the information required. Please address your response to the NRC Document Control Desk.
If you wish to meet with the staff to accelerate the information transfer, the staff would welcome such a meeting at a mutually convenient time. If you have any questions on this matter, I may be contacted by phone,301/415-2832, or by e-mail, pxw@nrc. gov.
Sincerely, 724 c. M Peter C. Wen, Project Manager Generic !ssues and Environmental i
Projects Branch Office of Nuclear Reactor Regulation
Enclosure:
Questions on topical report WCAP -15063-P 1
cc: See next page
i Questions for Topical Report WCAP-15063-P 1.
Please provide a list of those licensing analyses to which this creep model will be applied.
2.
Please provide the temperature, flux, fluence, and stress range to which this model will be applied.
3.
What is the specified fabrication range of tin content for Imp Zircaloy-4 (Zr-4)?
4.
Please provide the one-sigma uncertainty in the following coefficients to the creep model: A, B, C, Ci, C and C4, based on the data from which they were derived.
3 Also, please provide the data from which C was derived.
3 5.
Please provide the one-sigma uncertainties in the irradiation-hardening coefficient derived from the Zr-2.5Nb data.
6.
The derivation and application of coefficient C3 assumes that irradiation creep is directly proportional to the out-of-reactor thermal creep. The NRC reviewers are aware that ex-reactor creep data can qualitatively rank the irradiation creep of some zirconium alloys, but are not aware of any published data that demonstrates they can be linked quantitatively. Please provide data or a publication with data that substantiates that ex-reactor creep is quantitatively proportional to irradiation creep.
7.
The B&W/EPRI Oconee-2 in-reactor Zr-4 data are used in Section 3.2.1.2 of the report to demonstrate that the irradiation hardening factor for in-reactor thermal creep derived from Zr-2.5Nb data is conservative in relation to the irradiation hardening factor from this data. The B&W/EPRI Oconee-2 in-reactor data are dominated by irradiation creep, and thermal creep is negligible. Therefore, the derivation of an irradiation-hardening factor from the B&W/EPRI data for thermal creep is questionable. Please provide additional data or a publication with data that substantiates that the irradiation-hardening factor from Zr-2.5Nb material can be applied to Westinghouse Zr-4 cladding.
8.
The data used to determine the coefficients to the Westinghouse creep-model for Imp Zr-4 and ZlRLO are based on creep due to compressive stresses while the internal rod pressure analysis at end-of-life calculates creep due to tensile stresses.
Please provide cold-worked Zr-2 or Zr-4 tube data that demonstrates that compressive in-reactor creep data can be used to predict in-reactor creep under i
tensile stresses.
9.
Is the creep rate shown in Equations I and 2 the generalized (i.e., effective) creep rate, rather than hoop strain rate?
ENCLOSURE
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l l
10.
Is the constant (0.920) in Equation 16 directly imbedded in the constant C in i
l Equation 17? If not, please explain explicitly how PAD applies the creep strain I
rate to get hoop strain increments and hence cladding (inward) displacement during creepdown, and outward displacement during creepout.
11.
Why isn't strain hardening applied to the irradiation induced creep rate? Is there data to substantiate not doing so?
I l
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cc:
Mr. Nicholas Liparulo, Manager Equiprnent Design and Regulatory Engineering Westinghouse Electric Corporation Mail Stop ECE 4-15 P.O. Box 355 Pittsburgh, PA 15230-0355 Mr. Jack Bastin, Director Regulatory Affairs Westinghouse Electric Corporation 11921 Rockville Pike Suite 107 Rockville, MD 20852 Mr. Sumit Ray, Manager Fuel Licensing j
Westinghouse Electric Corporation PO Box 355 Pittsburgh, PA 15230-0355 i