CNRO-2004-00063, Relief Request ANO1-R&R-005 - Response to the NRCs Request for Additional Information

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Relief Request ANO1-R&R-005 - Response to the NRCs Request for Additional Information
ML042660428
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 09/16/2004
From: Burford F
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
CNRO-2004-00063
Download: ML042660428 (6)
v • d • e


Text

a-Entergy Entergy Operations, Inc.

1340 Echelon Parkway Jackson, Mississippi 39213-8298 Tel 601-368-5758 F. G. Burford Acting Director Nuclear Safety & Licensing CNRO-2004-00063 September 16, 2004 U. S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Relief Request ANO1-R&R-005 -

Response to the NRC's Request for Additional Information Arkansas Nuclear One, Unit 1 Docket No. 50-313 License No. DPR-51

REFERENCE:

Entergy Operations, Inc. letter CNRO-2004-00017 to the NRC dated March 10, 2004

Dear Sir or Madam:

In the referenced letter, Entergy Operations, Inc., (Entergy) submitted to the NRC staff Framatome Document 51-5021608, Corrosion Evaluation of ANOI CRDM IDTB Weld Repair, in support of Request for Alternative ANO1-R&R-005. In a recent telephone call, representatives from Entergy and the staff discussed ANO1-R&R-005 and the Framatome document. In that call, the staff requested that Entergy provide the basis for the general corrosion rate of 0.0032 inch/year used in ANO1-R&R-005. This basis is provided in the enclosure. In addition, Entergy withdraws Framatome Document 51-5021608 and requests its return in accordance with 10 CFR 2.390(c)(3).

Should you have any questions regarding this letter, please contact Guy Davant at (601) 368-5756.

This letter contains no new commitments.

Very truly yours, 4

4

'S FGB/GHD/ghd

Enclosure:

Response to NRC Request for Additional Information cc:

(see next page) 49

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CNRO-2004-00063 Page 2 of 2 cc:

Mr. W. A. Eaton (ECH)

Mr. J. S. Forbes (ANO)

Dr. Bruce. S. Mallett Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 U. S. Nuclear Regulatory Commission Attn: Mr. T. W. Alexion MS 0-7 D1 Washington, DC 20555-0001 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847

ENCLOSURE CNRO-2004-00063 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION

Enclosure to CNRO-2004-00063 Page 1 of 3 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION NRC Question What is the basis for the general corrosion rate of 0.0032 inch/year?

Entergy's Response The general corrosion rate was determined by Framatome-ANP (Framatome) for Entergy Operations, Inc. (Entergy) in support of potential repair activities on the ANO-1 reactor pressure vessel head. The basis for the rate is documented in Framatome Document 51-5021608, Corrosion Evaluation of ANOI CRDM IDTB Weld Repair, which is classified as proprietary by Framatome. As documented in this report, the general corrosion rate is based on industry experience over the past 40 years of commercial nuclear power operation. The discussion below provides a non-proprietary basis for the corrosion rate.

As documented in Framatome Document 51-5021608, general corrosion is defined as uniform deterioration of a surface by chemical or electrochemical reaction with the environment. Stainless steels and nickel-base alloys (e.g., Type 316, Alloy 600) are essentially immune to general corrosion in a PWR environment; however, carbon and low alloy steels are not. Corrosion can occur when carbon and low alloy steel base metal is exposed to primary coolant. During operating conditions, primary coolant is deaerated reaching 550° - 6500F depending on location within the reactor coolant system (RCS). During shutdown conditions, primary coolant temperature decreases to 700F and may become aerated or stagnant depending on the RCS location.

The primary RCS equipment, loop piping, pressurizer, reactor vessel, and steam generators are clad with either a stainless steel or nickel-base alloy in order to prevent corrosion of carbon and low alloy steel base metal. Throughout the operating history of domestic PWRs, there have been many cases where a localized area of the base metal has been exposed to primary coolant. These include:

SONGS, Unit 2 - hot leg Calvert Cliffs, Unit 2 - pressurizer In each case, the base metal was exposed to primary coolant in a localized area. Each plant returned to normal operation with the base metal exposed; Yankee Rowe operated for more than 30 years with exposed based metal.

Enclosure to CNRO-2004-00063 Page 2 of 3 Several studies, documented in publicly available reports (References I - 13), have been conducted that investigated the corrosion rates of carbon and alloy steels used in pressure boundary applications in various environments. Studies have shown that under deaerated (operating) conditions, the corrosion rate was dependent on temperature, fluid velocity, boric acid concentration, and time (Reference 1). In addition, the Electric Power Research Institute (EPRI) has published a handbook on boric acid corrosion (Reference 14) that summarizes industry experience, discusses boric acid corrosion mechanisms, and compiles corrosion tests and results.

Based on industry information and specific ANO-1 RCS parameters, the general corrosion rate used to support ANOI-R&R-005 was estimated by Framatome to be 0.0032 inch/year for operating and shutdown conditions within the RCS for an 18-month fuel cycle.

References

1. Whitman, G. D., et. al., A Review of Current Practice in Design, Analysis, Materials, Fabrication, Inspection, and Test, ORNL-NSIC-21, ORNL, December, 1967
2.

Vreeland, D. C., et. al., "Corrosion of Carbon and Lo-Alloy Steels in Out-of-Pile Boiling Water Reactor Environment," Corrosion, Vol. 17(6), June 1961, p. 269

3.

Vreeland, D. C., et. al., "Corrosion of Carbon and Other Steels in Simulated Boiling Water Reactor Environment: Phase II," Corrosion, Vol. 19(10), October 1962, p. 368

4.

Uhlig, H. H., and Revie, R. W., Corrosion and Corrosion Control, John Wiley & Sons, New York, 1985

5.

Copson, H. R. 'Effects of Velocity on Corrosion by Water," Ind. Eng. Chem., Vol., 44, p.

1745,1952

6.

Vreeland, D. C., et. al., "Corrosion of Carbon and Lo-Alloy Steels in Primary Systems of Water-Cooled Nuclear Reactors," presented at the Netherlands-Norwegian Reactor School, Kjeller, Norway, August 1963

7.

Pearl, W. C. and Wozadlo, G. P., Corrosion of Carbon Steel in Simulated Boiling Water and Superheated Reactor Environments, Corrosion, Vol. 21(8), August 1965, p. 260

8.

Tackett, D. E. et. al., "Review of Carbon Steel Corrosion Data in High Temperature, High Purity Water in Dynamic Systems, USAEC Report, WAPD-LSR(C)-134, Westinghouse Electric Corporation, October 14, 1955

9. DePaul, E. J., ed., "Corrosion and Wear Handbook for Water Cooled Reactors," USAEC Report, TID-7006, 1957
10. Ruther, W. E., and Hart, R. K., "Influence on Oxygen on High Temperature Aqueous Corrosion of Iron," Corrosion, Vol. 19(4), April 1963, p. 127t
11. Howells, E., and Vaughan, L. H., "Corrosion of Reactor Materials in Boric Acid Solutions,"

RDE-1086, Babcock & Wilcox Company, Alliance, Ohio, August 1960

Enclosure to CNRO-2004-00063 Page 3 of 3

12. Yankee Atomic Electric Company to the U. S. Atomic Energy Commission, 'Evaluation of Yankee Vessel Cladding Penetrations," WCAP-2855, License No. DPR-3, Docket No.,

50-29, October 15, 1965

13. "Absorption of Corrosion Hydrogen by A302B Steel at 70F to 500F," WCAP-7099, Westinghouse Electric Corporation, Pittsburg, Pennsylvania, December 1967
14. "Boric Acid Corrosion Guidebook," TR-104748, Electric Power Research Institute, Palo Alto, California, April 1995
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