ML061230511

Second Supplement to License Amendment Request to Increase Voltage Limit for Emergency Diesel Generator Load Rejection Surveillance Test

ML061230511
Person / Time
Site:	Cook
Issue date:	04/13/2006
From:	Fadel D Indiana Michigan Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
AEP:NRC:6381-02
Download: ML061230511 (5)

Text

INDIANA MICHIGAN POWER' A unit ofAmerican Electric Power Indiana Michigan Power Cook Nuclear Plant One Cook Place Bridgman, Ml 49106 AEP.com April 13, 2006 AEP:NRC:6381-02 10 CFR 50.9 1(a)(5)

U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop O-Pl-17 Washington, DC 20555-0001

References:

1.

Donald C. Cook Nuclear Plant Unit 1 and Unit 2 Docket Nos. 50-315 and 50-316 Second Supplement to License Amendment Request to Increase Voltage Limit for Emergency Diesel Generator Load Rejection Surveillance Test Letter from J. N. Jensen, Indiana Michigan Power Company (I&M) to U. S.

Nuclear Regulatory Commission (NRC) Document Control Desk, "License Amendment Request to Increase Voltage Limit for Emergency Diesel Generator Load Rejection Surveillance Test," dated April 10, 2006.

2. Letter from D. P Fadel, I&M, to U. S. NRC Document Control Desk, "Supplement to License Amendment Request to Increase Voltage Limit for Emergency Diesel Generator Load Rejection Surveillance Test,"

dated April 12, 2006.

Dear Sir or Madam:

This letter provides a second supplement to a proposed license amendment for the Donald C. Cook Nuclear Plant (CNP), Unit 1 and Unit 2.

By Reference 1, I&M proposed to amend Facility Operating Licenses DPR-58 and DPR-74 for CNP.

I&M proposed to increase the voltage limit for the emergency diesel generator (DG) full load rejection Technical Specification (TS) Surveillance Requirement (SR). The proposed amendment was requested on an emergency basis for Unit 2, pursuant to 10 CFR 50.91(a)(5). The proposed amendment was not requested on an emergency basis for Unit 1.

Reference 2 provided supplemental information regarding the proposed amendment.

I&M is providing additional supplemental information in response to discussions with the NRC staff regarding the proposed amendment. This supplemental information provides further assurance that the Unit 2 AB DG voltage regulator is operating properly and that the difficulty in meeting the full load eats

U. S. Nuclear Regulatory Commission AEP:NRC:6381-02 Page 2 rejection voltage limit is likely the result of the additional requirements involved in the conversion of the previous TS SR to the improved standard technical specifications of NUREG-1431 in September 2005.

The information provided in this letter consists of clarifying information for the amendment request previously submitted by Reference 1. The information in this letter does not alter the validity of the original evaluation of significant hazards considerations performed in accordance with 10 CFR 50.92, and documented in Enclosure 2 to Reference 1. The environmental assessment provided in Enclosure 2 to Reference 1 also remains valid. to this letter provides an affirmation affidavit pertaining to the supplemental information. provides the supplemental information.

Copies of this letter and its enclosures are being transmitted to the Michigan Public Service Commission and Michigan Department of Environmental Quality, in accordance with the requirements of 10 CFR 50.91.

There are no new regulatory commitments in this letter. Should you have any questions, please contact Mr. Michael K. Scarpello, Regulatory Affairs Supervisor, at (269) 466-2649.

Sincerely, Daniel P. ael Engineering Vice President JRW/jen

Enclosures:

1. Affirmation

2. Second Supplement to License Amendment Request to Increase Voltage Limit for Emergency Diesel Generator Load Rejection Surveillance Test c:

J. L. Caldwell, NRC Region III K D. Curry, AEP Ft. Wayne, wlo enclosures J. T. King, MPSC MDEQ - WHMD/RPMWS NRC Resident Inspector P. S. Tam, NRC Washington, DC to AEP:NRC:6381-02 AFFIRMATION I, Daniel P. Fadel, being duly sworn, state that I am Engineering Vice President of Indiana Michigan Power Company (I&M), that I am authorized to sign and file this request with the Nuclear Regulatory Commission on behalf of I&M, and that the statements made and the matters set forth herein pertaining to I&M are true and correct to the best of my knowledge, information, and belief.

Indiana Michigan Power Company Daniel P. Fade Engineering Vice President SWORR TQ AND SUBSCRIBED BEFORE ME

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Z37t DANIELLE M. BURGOYNE Notary Public, State of Mkhidgan County of Borden My Commission Expires Apr. 4, 2008 Acting in t*h cotv fltlp of to AEP:NRC:6381-02 SECOND SUPPLEMENT TO LICENSE AMENDMENT REQUEST TO INCREASE VOLTAGE LIMIT FOR EMERGENCY DIESEL GENERATOR LOAD REJECTION SURVEILLANCE TEST The current Donald C. Cook Nuclear Plant (CNP) Technical Specification (TS) Surveillance Requirement (SR) 3.8.1.11 requires verification that emergency diesel generator (DG) voltage is maintained less than or equal to (9) 5000 volts following a DG full load rejection. I&M has proposed a license amendment that would increase this limit to < 5350 volts.

I&M is providing supplemental information in response to discussions with the NRC staff regarding the proposed amendment. This supplemental information provides further assurance that the Unit 2 AB DG voltage regulator is operating properly and that the difficulty in meeting the full load rejection voltage limit is likely the result of the additional requirements involved in the conversion of the previous TS SR to the improved standard technical specifications of NUREG-1431 in September 2005.

The conversion of -the previous DG full load rejection TS SR to the improved standard technical specifications of NUREG-1431 resulted in the addition of a limit for the power factor (< 0.86).

This limit resulted in higher voltages following the full load rejection. I&M has conducted the following tests incorporating a power factor adjustment to demonstrate proper operation of the voltage regulator.

Three Full Load Rejection Tests Results from all three tests, performed on both the installed and replacement voltage regulators, including those performed before optimum tuning, fall within approximately two percent of the peak voltage. After voltage regulator tuning, the results fall within approximately 1 percent of the peak voltage. These are repeatable results that provide high confidence that the voltage regulator is performing as designed.

Eight Hour Full Load Power Factor Adjusted Test This test was performed on the installed voltage regulator with the power factor between 0.80 and 0.86. During initial power factor adjustment, and reactive load sharing during the run, all regulator responses were normal.

Full Load Runs With Reactive Load Minimized (Power Factor Maintained as Close as Possible To 1.0)

These tests were performed on both the installed and replacement regulators. Although not at reduced power factor, these runs still require voltage regulator adjustment to minimize reactive load. Normal voltage was maintained, with no problems minimizing reactive currents (reactive load sharing capability with grid normal).

to AEP:NRC:6381-02 Page 2 I&M has also conducted the following tests not incorporating a power factor adjustment to demonstrate proper operation of the voltage regulator.

Sequential Loading Tests Proper voltage response was observed during the sequential loading evolutions.

Single Largest Load Rejection Test Proper voltage response was observed during this test on the installed regulator. Although this test includes some reactive load, it is not power factor adjusted.

Fast Start Test Proper voltage response was noted during fast start tests on both the installed and replacement regulator.

Half Load (1750 kilowatt) Reject Tests Proper voltage response was observed during these tests on the replacement regulator.

After replacement of the regulator, voltage regulator response was assessed based on response during:

• Full load rejection tests

• Fast starts

• Half load rejection test

• Full load run Performance during all of these tests was consistent with that previously observed. The results of the full load rejection tests performed on the replacement voltage regulator were compared to the results of the previous power factor adjusted full load rejection test results performed on the installed Unit 2AB DG voltage regulator. Consistent results were observed.

Each test provides a data point by which voltage regulator response can be assessed. All of these tests provided indication of normal voltage regulator and governor (real load/mechanical effects) response.