HNP-08-058, Emergency Core Cooling System Evaluation Changes
| ML081560215 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 05/28/2008 |
| From: | Corlett D Progress Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| HNP-08-058 | |
| Download: ML081560215 (5) | |
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Progress Energy HAY 2 '8 2008 SERIAL: HNP-08-058 10 CFR 50.46 U. S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 EMERGENCY CORE COOLING SYSTEM EVALUATION CHANGES Ladies and Gentlemen:
In accordance with the Code of Federal Regulations, Title 10, Part 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors,"
paragraph (a)(3)(ii), the Harris Nuclear Plant (HNP), of Carolina Power & Light Company doing business as Progress Energy Carolinas, Inc., submits its annual report regarding the effect of changes or errors in the application of the Emergency Core Cooling System (ECCS) evaluation models.
The HNP ECCS performance following a large break loss of coolant accident (LBLOCA) is calculated for HNP by AREVA NP using the SEM/PWR-98 ECCS Evaluation Model for PWR LBLOCA Applications. The ECCS performance following a small break loss of coolant accident (SBLOCA) is calculated for HNP by AREVA NP using the EXEM PWR Small Break Model.
The previous HNP annual report to the NRC was provided by letter dated June 1, 2007, which documented a SBLOCA peak clad temperature (PCT) of 16580F and a LBLOCA PCT of 2102 0F. Since that report, no errors or changes in the LOCA models or results have been made that would require a 30-day report under 10 CFR 50.46. The new value for the SBLOCA PCT is 1650 0F, and the new value for the LBLOCA PCT is 20810 F. provides a summary of the impact of changes and errors on PCT since the June 2007 report. provides a summary of the errors associated with the SBLOCA model since the June 2007 report. provides a summary of the changes associated with the LBLOCA model since the June 2007 report.
Progress Energy Carolinas, Inc.
Harris Nuclear Plant P. 0. Box 165 New Hill, NC 27562
Page 2 Serial: HNP-08-058 This letter contains no new regulatory commitments. Please contact me if you have any questions regarding this submittal at (919) 362-3137.
Sincerely, D. H. Corlett Supervisor, Licensing - Regulatory Programs Harris Nuclear Plant DHC/mgw Attachments:
- 1. Summary of the Impact of Changes and Errors on Peak Clad Temperature
- 2. Summary of the Errors Associated with the Small Break LOCA Model
- 3. Summary of the Changes Associated with the Large Break LOCA Model c: Mr. P. B. O'Bryan (NRC Sr. Resident Inspector, HNP)
Mr. L. A. Reyes (NRC Regional Administrator, Region II)
Ms. M. G. Vaaler (NRC Project Manager, HNP) to SERIAL: HNP-08-058 Summary of the Impact of Changes and Errors on Peak Clad Temperature Harris Nuclear Plant Small Break LOCA Peak Clad Temperature Summary Peak Clad Temperature (*F)
Value Reported 6/1/2007 1658 Reported Error Impact New SBLOCA PCT Value
-8 1650 Harris Nuclear Plant Large Break LOCA Peak Clad Temperature Summary Peak Clad Temperature (°F)
Value Reported 6/1/2007 2102 Reported Change Impact
-21 New LBLOCA PCT Value 2081 Page A1-1 of 1 to SERIAL: HNP-08-058 Summary of the Errors Associated With the Small Break LOCA Model Small Break LOCA Reactor Kinetic Model Progqramming Error AREVA NP (the HNP nuclear fuel and safety analysis vendor) was informed that the programming for the point kinetics equation in RELAP5 has an error that results in the over prediction of reactor power. RELAP5 is used in the EXEM Small Break Model (topical report XN-NF-82-49). The original error occurred in the development of the RELAP5 software at Idaho National Laboratory. The impact of the error is an estimated 8 OF reduction of the Peak Clad Temperature (PCT). The current PCT is now estimated at 1650 OF and includes several downward adjustments previously reported to the NRC.
There are no immediate plans to re-analyze the Small Break Loss of Coolant Accident (SBLOCA) due to the large margin between the result and the 10CFR 50.46 limit and because the individual errors have been assessed in the downward direction.
Page A2-1 of 1 to SERIAL: HNP-08-058 Summary of the Changes Associated with the Large Break LOCA Model Large Break LOCA Re-analysis The Large Break Loss of Coolant Accident (LBLOCA) analysis was re-performed to support changing the limiting axial power shape and k(z) curve. The re-analysis also included incorporation of previously identified errors reported against LBLOCA. The revised analysis was put into place with the startup of Cycle 15 (Fall of 2007). The revised LBLOCA analysis decreased the peak clad temperature (PCT) to 2081 OF. The previous value for PCT was 2102 OF and included several estimated errors. The impact of the change is an estimated 21 OF reduction of the Peak Clad Temperature (PCT).
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