ML033640583
| ML033640583 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/22/2003 |
| From: | William Holston Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP1L 1802 | |
| Download: ML033640583 (2) | |
Text
P.O. Box 63 Lycoming, New York 13093 Constellation Energy Group Nine Mile Point Nuclear Station December 22, 2003 NMP1L 1802 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Nine Mile Point Units 1 and 2 Docket No. 50-220 and 50-410 DPR-63 and NPF-69 IOCFR50.46(a)(3)(ii) Report Gentlemen:
Pursuant to 10CFR50.46(a)(3Xii), this letter provides this year's annual report concerning changes to, or errors discovered in, the emergency core cooling system (ECCS) evaluation model used for Nine Mile Point Units 1 and 2 (NMP1 and NMP2). Last year's annual report was submitted on December 23, 2002 (NWP1L 1700). Since then, Global Nuclear Fuel-Americas (GNF), the fuel vendor for NMPW and NMP2, has reported two new errors in the latest approved ECCS analysis, which affect the peak clad temperature (PCT) calculations.
The first case was an error in the SAFER initial separator pressure drop in the evaluation model for NMP, which resulted in a higher initial steam separator pressure drop and an overly restricted flow through the separator during the loss of coolant accident (LOCA). An evaluation determined that the increase in PCT due to this change is 5° F for NMPI. The second case was an error in the SAFER Level/Volume Table used in the evaluation model for NMP2, which resulted in an incorrect volume split in the nodes above and below the water surface and incorrect initial liquid mass. An evaluation was performed which determined that the impact on PCT due to this error is -5° F for NMP2.
Based on the above, the maximum increase in PCT due to changes or errors in the latest analysis is 150 F for NMP and 0° F for NMP2. The sum of the absolute values of the effect on PCT of all changes or errors in the latest approved ECCS analysis is 150 F for NMP and 50 F for NMP2.
Page 2 NMP1L 1802 The maximum anticipated PCT during a LOCA remains less than 22000 F for NMPW and NMP2.
The cumulative effect on PCT of changes and errors identified since the latest approved ECCS analysis remains less than 500 F for NMP 1 and NMP2, and, therefore, is not significant according to the criterion stated in 10CFR50.46(a)(3)Ci).
Very truly yours, 9a a/$
William C. Holston Manager Engineering Services WCHILAA/bjh cc:
Mr. H. J. Miller, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Mr. P. S. Tam, Senior Project Manager, NRR (2 copies)