ML18067A522

Provides Notification of Significant Change or Error in Emergency Core Cooling Analysis.Change in Peak Clad Temp Between Cycle 12 & Cycle 13 Due Primarily to Listed Factors

ML18067A522
Person / Time
Site:	Palisades
Issue date:	04/30/1997
From:	Bordine T CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9705070178
Download: ML18067A522 (2)

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April 30, 1997 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT NOTIFICATION UNDER 10 CFR 50.46 OF CHANGE IN ECCS CALCULATION RESULTS 10CFR50.46(a)(3)(ii) requires a report to be submitted within thirty days of discovery of a significant change or error in an Emergency Core Cooling (ECCS) analysis.

"Significant" is defined in 10CFR50.46(a)(3)(i) as any change in predicted peak clad temperature (PCT) of greater than 50°F. The purpose of this letter is to report a reduction in analyzed PCT of greater than 50°F for the Palisades Large Break Loss of Coolant Accident (LBLOCA).

In a letter dated January 20, 1997, Consumers Energy reported that the PCT predicted by the LBLOCA analysis for fuel Cycle 12 had been revised from 2095°F to 1991°F.

This analysis change had actually been made by Siemens Power Corporation (SPC) in 1S95, but it was not reported to Consumers Energy until December 20, 1996. On December 27, 1996, Palisades completed a refueling outage and began Cycle 13 operation. On April 11, 1997, during a self-assessment of ECCS analysis changes, it was determined that an additional report should have been made concerning LBLOCA analysis changes made for fuel Cycle 13.

The revised LBLOCA analysis for Cycle 13 predicted a PCT of 1892°F. This constituted a 99°F reduction from the Cycle 12 value. This reduction was not due to errors in analysis models, but rather to changes in SPC LBLOCA methodology and input assumptions. The change in PCT between Cycle 12 and Cycle 13 was due

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Palisades Nuclear Plant

• 27780 Blue Star Memorial Highway

• Coveil, Ml 49043

• Tel: 616164 2913

• Fax: 616164 2490

• 2 The steam generators were modeled to support maximum tube plugging levels of 15% in either or both rather than the previously assumed plugging levels of 29.3%. The replacement steam generators installed in 1991 currently have less than 4% of their tubes plugged.

Revised Safety Injection_ Tank line losses were utilized.

Revised core fuel (pellet density and enrichments) and neutronics (peaking factor and reactivity coefficients) values were utilized to reflect the cycle 13 core design and reload Q fuel.

Revised High and Low Pressure Safety Injection and Containment Spray pump flow rate curves were utilized.

The Cycle 13 LBLOCA analysis demonstrates that the criteria of 10CFRS0.46 continue to be satisfied. Both Cycle 12 and Cycle 13 analyses were performed using NRC-:

approved SPC methodology consistent with the requirements of 10CFRSO Appenpix K.

Consumers Energy recognizes that this report should have been submitted within 30.

days of startup from the refueling outage preceding Cycle 13 operation. The reasons for this late report are being evaluated within the Palisades Corrective Action System.

Appropriate corrective actions will be taken.

SUMMARY

OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.

Thomas C. Berdine Manager, Licensing CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades