ML093491051

Draft Request for Additional Information from Electrical Engineering Branch AFW

ML093491051
Person / Time
Site:	Point Beach
Issue date:	12/15/2009
From:	Justin Poole Plant Licensing Branch III
To:	Jim Costedio, Hale S Point Beach
Poole Justin/DORL/LPL3-1/ 301-415-2048
References
Download: ML093491051 (3)

Text

From:

Poole, Justin Sent:

Tuesday, December 15, 2009 3:22 PM To:

'Hale, Steve'; 'COSTEDIO, JAMES'

Subject:

Draft Request for Additional Information from Electrical Engineering Branch RE: AFW

Steve, By letter to the U.S. Nuclear Regulatory Commission (NRC) dated April 7, 2009, as supplemented by two letters dated June 17, and September 25, 2009, FPL Energy Point Beach, LLC, submitted a request to change technical specifications due to modifications to the auxiliary feedwater system (AFW). This was originally part of the extended power uprate request, but was separated out by the NRC staff.

The Technical Specification Branch has reviewed the information provided and determined that in order to complete its evaluation, additional information is required. We would like to discuss the questions, in draft form below, with you in a conference call.

This e-mail aims solely to prepare you and others for the proposed conference call. It does not convey a formal NRC staff position, and it does not formally request for additional information.

Justin C. Poole Project Manager NRR/DORL/LPL3-1 U.S. Nuclear Regulatory Commission (301)415-2048 email: Justin.Poole@nrc.gov

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DRAFT

1. In response to staffs RAI dated August 26, 2009, regarding the EDG voltage dip below the acceptance limit of 75 percent nominal voltage during motor start, the licensee stated that the EDGs are capable of starting safeguard loads and the voltage recovers quickly to the acceptable level. Based on staffs review of the dynamic loading calculations, the staff notes that under certain loading conditions for Train A EDG, the frequency is outside 2 percent margin, the worst-case voltage dip is 45-48 percent and the voltage overshoot is 129.5 percent. Train A voltage and frequency variations are outside the industry accepted standards and guidance Provide detailed analyses regarding the downstream effects on components such as contactors, control fuses, inverters, battery chargers, solenoids, MOVs, solid state devices, etc., and the basis to show that all required loads will start and continue to run with sufficient margins after accounting for any uncertainties. Provide justification for the performance capabilities of the EDG A regulator and excitation systems to support shutdown equipment within design basis requirements during a DBA. The staff notes that Train B EDG bus voltages remain above 75% of nominal voltage, consistent with NRC Regulatory Guide 1.9, throughout the motor starting sequence in all postulated loading conditions. Provide a summary of all bus voltages for the B train distribution system.

2. The cables for new AFW pump motors are planned to be routed through the existing duct banks and manholes which are susceptible to moisture, wet or flooding conditions.

The staffs review of Point Beachs operating experience indicates that, since 1997, numerous corrective action documents were generated to capture concerns associated with cable submergence and water ingress through underground cableways and manholes. Provide cable design specifications and manufacturers certification to provide assurance that these cables are designed for the environment they will be subjected to. Also, provide details of the proposed initial tests and periodic tests for these cables including the type of tests and the frequency.

3. In response to staffs RAI dated August 26, 2009, regarding EDG/loss of voltage relay time delays, the licensee stated that the EDG output breaker closure within 14 seconds is consistent with accident analysis. The staff notes that this is inconsistent with the design/licensing basis for the EDGs. Specifically, FSAR Section 8.8.1, Design Basis, states that the EDGs are required to start and be ready for loading within 10 seconds after receiving a start signal. In addition, Section 8.8.3 states that the time from receipt of start signal to EDG ready to accept load shall not exceed 10 seconds (reaches its rated speed and voltage and the associated breaker closes automatically to reenergize the safeguard buses). The staff notes that the existing EDG design (time delays for output breaker closure is 14 seconds) is inconsistent with chapter 8 design basis requirements. Explain the inconsistency and identify all the loads that are started on the safety bus at 10 seconds in accordance with Chapter 8 design basis.

4. Explain how the EDG fuel oil consumption and volume calculation accounted for additional fuel oil requirements for AFW and other plant modifications. What is the basis for removing 10% margin from the original fuel oil consumption calculation? Provide details on how instrument uncertainties, instrument errors, temperature effects and specific gravity variations were accounted for in the calculation?

5. In response to staffs RAI dated August 26, 2009, regarding environmental parameters for the AFW motor location, the licensee stated that the normal radiation level is 1300 RAD for 60-year TID and the AFW pumps and associated equipment will not be included in the EQ program since they are not credited in the accident analysis although they are sequenced loads used in a LOCA. Please identify all electronic components installed in this area and the effects of these components on other safety related components if they are not qualified in accordance with 10 CFR 50.49.

6. In response to staffs RAI dated June 2, 2009, regarding the surveillance tests for EDGs, the licensee proposed new TS surveillance SR 3.8.1.7 requirement (the performance of a 24-hour endurance and load margin test of each EDG). The staff notes that the proposed EDG endurance and margin test does not envelop the accident loads for the entire duration of the 24-hr run. Specifically, EDGs G-01 and G-02 are loaded to 98.2%

to 100.9% of the 2000-hour load rating for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 90 to 100% of the 2000-hour load rating for the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />; G-03 and G-04 EDGs are loaded to 97.4% to 100% of the 200-hour load rating for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 90 to 100% of the 2000-hour load rating for the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> with EDGs operating at the highest end of the 2-hour load range for 5 minutes. This is not consistent with RG 1.9 recommendations. The intent of the 24-hr test is to demonstrate that the EDG can operate at maximum postulated accident loads for extended duration. The 2-hour test requirement at a higher loading demonstrates design margins. Therefore, staff requests the licensee to provide basis why the proposed loading ranges are adequate to demonstrate the capability of

the EDGs to operate for its intended mission time. Also, explain why EDGs designated for each unit cannot be tested during modes other than modes 1 and 2 as recommended in NUREG-1431.

DRAFT