RNP-RA/04-0146, Response to NRC Request for Additional Information Regarding Technical Specifications Revision of Pressure/Temperature Limits

Response to NRC Request for Additional Information Regarding Technical Specifications Revision of Pressure/Temperature Limits

ML043410088
Person / Time
Site:	Robinson
Issue date:	12/02/2004
From:	Lucas J Progress Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RNP-RA/04-0146
Download: ML043410088 (4)

Text

Progress Energy Serial: RNP-RA/04-0146 DEC 0 2 2004 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/LICENSE NO. DPR-23 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING TECHNICAL SPECIFICATIONS REVISION OF PRESSURE/TEMPERATURE LIMITS Ladies and Gentlemen:

In a letter dated August 19, 2004, Progress Energy Carolinas, Inc. (PEC), also known as Carolina Power and Light Company, requested a Technical Specifications amendment for H. B. Robinson Steam Electric Plant, Unit No. 2, related to the Reactor Coolant System pressure/temperature limits. In a telephone call between the NRC and PEC on November 18, 2004, the NRC finalized a Request for Additional Information (RAI) related to the amendment request. Attachment II provides the required response to this RAI.

Attachment I provides an Affirmation in accordance with the provisions of Section 182a of the Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f).

If you have any questions concerning this matter, please contact Mr. C. T. Baucom at (843) 857-1253.

Sincerely, c2 C:Cs Jan F. Lucas Manager - Support Services - Nuclear RAC/rac Attachments: I. Affirmation II. Response to NRC Request for Additional Information Regarding Technical Specifications Revision of Pressure/Temperature Limits C: Dr. W. D. Travers, NRC, Region II Mr. C. P. Patel, NRC, NRR NRC Resident Inspector Progress Energy Carolinas, Inc.

Robinson Nuclear Plant 3581 West Entrance Road Hartsville, SC 29550

. I United States Nuclear Regulatory Commission Attachment I to Serial: RNP-RA/04-0146 Page I of 1 AFFIRMATION The information contained in letter RNP-RA/04-0146 is true and correct to the best of my information, knowledge and belief; and the sources of my information are officers, employees, contractors, and agents of Progress Energy Carolinas, Inc., also known as Carolina Power and Light Company. I declare under penalty of perjury that thei.

Executed On: I °z ° 61 W. G. Noll Director - Site Operations H. B. Robinson Steam Electric Plant, Unit No. 2

IS United States Nuclear Regulatory Commission Attachment II to Serial: RNP-RA/04-0146 Page 1 of 2 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING TECHNICAL SPECIFICATIONS REVISION OF PRESSURE/TEMPERATURE LIMITS NRC Ouestion 1 Table 22 of WCAP-15827 indicated that the limiting material at the high temperature portion (highlighted by bolded numbers) of the cooldown limits is the circumferential weld 10-273, while the limiting material at the low temperature portion of the cooldown limits is the upper shell plate W10201-1. It appears that the opposite is true. At low temperatures, the reduction in stress intensity factor due to the circumferential flaw assumption for the circumferential weld is not pronounced because the pressure is low. Therefore, the circumferential weld with an Adjusted Reference Temperature (ART) value of 2420 F, as compared with 1670 F for the plate, tends to be limiting at low temperatures. At high temperatures, the reduction in stress intensity factor due to the circumferential flaw assumption for the circumferential weld is significant because the pressure is high. Hence, the circumferential weld may lose its role as the limiting material. Please clarify this by providing the pressure, the pressure stress intensity factors, and the thermal stress intensity factors at 60'F and 250'F for both plate W10201-1 and weld 10-273 to demonstrate that you have selected the right limiting material for the cooldown curves.

Response 1 The requested information is as follows:

1. 35 EFPY Cooldown (100°Flhr) for plate W10201-1

• Reactor Pressure Vessel Bulk Water Temperature = 60'F

• 1/4T Metal Temperature = 88.9 0 F

• 1/4T Krr = 18.5977 KSI square root inches

• 1/4T Kip = 9.4741 KSI square root inches

• Allowable Pressure = 400 psig

• Reactor Pressure Vessel Bulk Water Temperature = 2500 F

• 1/4T Metal Temperature = 282.60 F

• 1/4T Krr = 21.6628 KSI square root inches

• 1/4T Kip = 110.4902 KSI square root inches

• Allowable Pressure = 4670 psig

United States Nuclear Regulatory Commission Attachment II to Serial: RNP-RA/04-0146 Page 2 of 2

2. 35 EFPY Cooldown (100 0 F/hr) for the circumferential weld 10-273

• Reactor Pressure Vessel Bulk Water Temperature = 60'F

• 1/4T Metal Temperature = 88.90 F

• 1/4T Krr = 18.5977 KSI square root inches

• 1/4T K1p = 7.7837 KSI square root inches

• Allowable Pressure = 688 psig

• Reactor Pressure Vessel Bulk Water Temperature = 250'F

• 1/4T Metal Temperature = 282.60 F

• 1/4T Krr = 21.6628 KSI square root inches

• 1/4T K1p = 29.1328 KSI square root inches

• Allowable Pressure = 2574 psig Where, Krris the Thermal Stress Intensity Factor Kip is the Pressure Stress Intensity Factor Also note that Krr and the Reference Stress Intensity Factor (KIC) are calculated first, and then the following equation is solved for Kip:

2Kjp + Krr = Kic Kip = Mm

• pRI/t Where, Ri = Radius to the Clad Base Metal Interface = 77.969 inches t = Vessel Thickness = 9.313 inches Mm for Circumferential Weld = 1.352 Mm for Plate = 2.825 Thus, Allowable Pressure, p = (Kic - KrT)/[2*Mm*(Ri/t)].

Use of the above values supports the limiting materials specified in WCAP-15827.