ML061350255

DC Cook Unit 1 - Issuance of Amendment Emergency Diesel Generator Full Load Rejection Voltage Test Limit

ML061350255
Person / Time
Site:	Cook
Issue date:	09/01/2006
From:	Tam P NRC/NRR/ADRO/DORL/LPLE
To:	Nazar M Indiana Michigan Power Co
Peter Tam
Shared Package
ML062010589	List: ML061350255 ML062490114
References
TAC MD1130
Download: ML061350255 (11)

Text

September 1, 2006Mr. Mano K. NazarSenior Vice President and Chief Nuclear Officer Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106

SUBJECT:

DONALD C. COOK NUCLEAR PLANT, UNIT 1 (DCCNP-1) - ISSUANCE OFAMENDMENT REGARDING DIESEL GENERATOR VOLTAGE LIMIT REQUIREMENTS (TAC NO. MD1130)

Dear Mr. Nazar:

The Commission has issued the enclosed Amendment No. 295 to Renewed Facility OperatingLicense No. DPR-58 for DCCNP-1. The amendment consists of changes to the TechnicalSpecifications in response to your application dated April 10, 2006, as supplemented by lettersdated April 12, 13 (two letters), and June 27, 2006. A similar amendment was issued on April 13, 2006, to DCCNP-2 under emergency circumstances.The amendment revised Surveillance Requirement 3.8.1.11 of the DCCNP-1 TechnicalSpecifications, raising the diesel generator load rejection voltage test limit from 5000 volts to 5350 volts.A copy of our related safety evaluation is enclosed. A Notice of Issuance will be included in theCommission's next biweekly Federal Register notice.Sincerely,/RA/Peter S. Tam, Senior Project ManagerPlant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-315

Enclosures:

1. Amendment No. 295 to DPR-58

2. Safety Evaluationcc w/encls: See next page Mr. Mano K. NazarSeptember 1, 2006Senior Vice President and Chief Nuclear Officer Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106

SUBJECT:

DONALD C. COOK NUCLEAR PLANT, UNIT 1 (DCCNP-1) - ISSUANCE OFAMENDMENT REGARDING DIESEL GENERATOR VOLTAGE LIMIT REQUIREMENTS (TAC NO. MD1130)

Dear Mr. Nazar:

The Commission has issued the enclosed Amendment No. 295 to Renewed Facility OperatingLicense No. DPR-58 for DCCNP-1. The amendment consists of changes to the TechnicalSpecifications in response to your application dated April 10, 2006, as supplemented by lettersdated April 12, 13 (two letters), and June 27, 2006. A similar amendment was issued on April 13, 2006, to DCCNP-2 under emergency circumstances.The amendment revised Surveillance Requirement 3.8.1.11 of the DCCNP-1 TechnicalSpecifications, raising the diesel generator load rejection voltage test limit from 5000 volts to 5350 volts.A copy of our related safety evaluation is enclosed. A Notice of Issuance will be included in theCommission's next biweekly Federal Register notice.Sincerely,/RA/Peter S. Tam, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-315

Enclosures:

1. Amendment No. 295 to DPR-58

2. Safety Evaluation cc w/encls: See next pageDISTRIBUTIONPUBLICGHill, OISLPL3-1 R/FRidsOGCRpRidsNrrLATHarrisRidsNrrPMPTamRidsNrrPMKFeintuch RidsDorlDprRidsNrrDirsltsbRidsAcrsAcnwMailCenter APalRidsRgn3MailCenterPackage Accession Number: ML062010589Amendment Accession Number: ML061350255TS Page Accession Number: ML0062490114OFFICENRR:LPL3-1/PMNRR:LPL3-1/LANRR:EEEB/BCOGCNRR:LPL3-1/BC(A)NAMEPTamTHarrisGWilsonMLemoncelliMMurphyDATE7/21/067/21/067/26/068/3/069/1/06OFFICIAL RECORD COPY Donald C. Cook Nuclear Plant, Units 1 and 2 cc:Regional Administrator, Region IIIU.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville RoadLisle, IL 60532-4351Attorney GeneralDepartment of Attorney General 525 West Ottawa Street Lansing, MI 48913Township SupervisorLake Township Hall

P.O. Box 818 Bridgman, MI 49106U.S. Nuclear Regulatory CommissionResident Inspector's Office 7700 Red Arrow Highway Stevensville, MI 49127James M. Petro, Jr., EsquireIndiana Michigan Power Company One Cook Place Bridgman, MI 49106Mayor, City of Bridgman P.O. Box 366 Bridgman, MI 49106Special Assistant to the GovernorRoom 1 - State Capitol Lansing, MI 48909Mr. John A. ZwolinskiSafety Assurance Director Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106Michigan Department of Environmental Quality Waste and Hazardous Materials Div.

Hazardous Waste & Radiological Protection Section Nuclear Facilities Unit Constitution Hall, Lower-Level North 525 West Allegan Street P. O. Box 30241 Lansing, MI 48909-7741Lawrence J. Weber, Plant ManagerIndiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106Mr. Joseph N. Jensen, Site Vice President Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106 INDIANA MICHIGAN POWER COMPANYDOCKET NO. 50-315DONALD C. COOK NUCLEAR PLANT, UNIT 1AMENDMENT TO RENEWED FACILITY OPERATING LICENSEAmendment No. 295 License No. DPR-581.The U.S. Nuclear Regulatory Commission (the Commission) has found that:A.The application for amendment by Indiana Michigan Power Company (thelicensee) dated April 10, 2006, as supplemented by letters dated April 12, 13 (two letters), and June 27, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I;B.The facility will operate in conformity with the application, the provisions of the Act,and the rules and regulations of the Commission;C.There is reasonable assurance (i) that the activities authorized by this amendmentcan be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission'sregulations;D.The issuance of this amendment will not be inimical to the common defense andsecurity or to the health and safety of the public; andE.The issuance of this amendment is in accordance with 10 CFR Part 51 of theCommission's regulations and all applicable requirements have been satisfied. 2.Accordingly, the license is amended by changes to the Renewed Facility OperatingLicense and Technical Specifications as indicated in the attachment to this license amendment.3.This license amendment is effective as of its date of issuance and shall be implementedwithin 45 days.FOR THE NUCLEAR REGULATORY COMMISSION/RA/Martin C, Murphy, Acting ChiefPlant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Renewed Operating License Date of Issuance: September 1, 2006 ATTACHMENT TO LICENSE AMENDMENT NO. 295RENEWED FACILITY OPERATING LICENSE NO. DPR-58DOCKET NO. 50-315Replace the following page of Renewed Facility Operating License No. DPR-58 with theattached revised page. The change area is identified by a marginal line.REMOVEINSERT 33Replace the following page of Appendix A, Technical Specifications, with the attached revisedpage. The change area is identified by a marginal line.REMOVEINSERT3.8.1-103.8.1-10 and radiation monitoring equipment calibration, and as fission detectors inamounts as required.(4)Pursuant to the Act and 10 CFR Parts 30, 40, and 70, to receive, possess anduse in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument and equipment calibration or associated with radioactive apparatus or components; and (5)Pursuant to the Act and 10 CFR 30 and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.C.This renewed operating license shall be deemed to contain and is subject to theconditions specified in the following Commission regulations in 10 CFR Chapter I: Part 20, Section 30.34 of Part 30, Section 40.41 of Part 40, Section 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; and is subject to all applicable provisions of thee Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:(1)Maximum Power LevelThe licensee is authorized to operate the facility at steady state reactor corepower levels not to exceed 3304 megawatts thermal in accordance with the conditions specified therein.(2)Technical SpecificationsThe Technical Specifications contained in Appendix A and Appendix B, asrevised through Amendment No. 295, are hereby incorporated in the renewedl operating license. The licensee shall operate the facility in accordance with theTechnical Specifications.(3)Less Than Four Loop OperationThe licensee shall not operate the reactor at power levels above P-7 (as definedin Table 3.3.1-1 of Specification 3.3.1 of Appendix A to this renewed operatinglicense) with less than four reactor coolant loops in operation until (a) safety analyses for less than four loop operation have been submitted, and (b) approval for less than found loop operation at power levels above P-7 has been granted by the Commission by amendment of this license.

(4)Indiana Michigan Power Company shall implement and maintain, in effect, allprovisions of the approved Fire Protection Program as described in the Final Safety Analysis Report for the facility and as approved in the SERs datedDecember 12, 1977, July 31, 1979, January 10, 1981, February 7, 1983,November 22, 1983, December 23, 1983, March 16, 1984, August 27, 1985 Renewed License No. DPR-58 Amendment No. 1 through 294 , 295 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION AMENDMENT NO. 295 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-58INDIANA MICHIGAN POWER COMPANYDONALD C. COOK NUCLEAR PLANT, UNIT 1DOCKET NO. 50-31

51.0INTRODUCTION

By application to the U.S. Nuclear Regulatory Commission (NRC, Commission) dated April 10,2006 (Accession No. ML061080660), as supplemented by letters dated April 12 (Accession No.

ML061240382), 13 (two letters, Accession Nos. ML061150354 and ML061230511), and June 27, 2006 (Accession No. ML061870388), Indiana Michigan Power Company (I&M, or the licensee) requested an amendment to the Operating Licenses for Donald C. Cook Nuclear Plant, Units 1 and 2 (DCCNP-1 and DCCNP-2). The proposed amendment would reviseSurveillance Requirement (SR) 3.8.1.11 of the Technical Specifications (TSs), changing the ABdiesel generator (DG) load rejection voltage limit from 5000 volts to 5350 volts.The licensee requested that the application for DCCNP-2 be processed under emergencycircumstances; accordingly, the DCCNP-2 amendment was issued on April 13, 2006. Thissafety evaluation addresses only the application for DCCNP-1.The supplemental letters contained clarifying information and did not change the initial nosignificant hazards consideration determination, and did not expand the scope of the originalFederal Register notice.

2.0REGULATORY EVALUATION

The regulatory requirements that the NRC staff applied in its review of the application include:General Design Criterion* (GDC) 17, "Electric power systems," of Appendix A, "General DesignCriteria for Nuclear Power Plants," to Title10, Part 50, of the Code of Federal Regulations(CFR) requires, in part, that nuclear power plants have onsite and offsite electric power systemsto permit the functioning of structures, systems, and components that are important to safety. The onsite system is required to have sufficient independence, redundan cy, and testability toperform its safety function, assuming a single failure. The offsite power system is required tobe supplied by two physically independent circuits that are designed and located so as to minimize, to the extent practical, the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions. In addition, this criterion requires provisions to minimize the probability of losing electric power from the remaining electric power supplies asa result of loss of power from the unit, the offsite transmission network, or the onsite power supplies.

• DCCNP-1 was constructed before promulgation of the General Design Criteria in 10 CFR Part 50. The NRC staffused the GDCs in this safety evaluation solely as a convenient summary of acceptable standards. GDC-18*, "Inspection and testing of electric power systems," requires that electric powersystems that are important to safety must be designed to permit appropriate periodic inspectionand testing. Title 10, Part 50, of the Code of Federal Regulations 50.36*, "Technical Specifications,"requires a licensee's TS to establish Limiting Conditions of Operation and SRs for equipment that is required for safe operation of the facility.

3.0BACKGROUND

The licensee stated that existing SR 3.8.1.11 requires verification, at least once per 24 months,that each DG does not trip and voltage is maintained 5000 volts during and following a fullload rejection, i.e., rejection of a load greater than or equal to () 3150 kilowatts (kW) and3500 kW. The basis for the 5000 volt limit is DG damage protection. During a performance ofSR 3.8.1.11 for the DCCNP-2 AB DG on March 26, 2006, the maximum measured voltage was4993 volts. Adding the 55 volts instrument uncertainty margin to the measured values resulted in a test value of 5048 volts, which exceeded the 5000 volt TS criterion.The licensee replaced the DCCNP-2 voltage regulator and tuned it to optimiz e the systemresponse. The full load rejection test was performed on April 8, 2006. During this test, the peak measured voltage reached 5105 volts, again exceeding the test criterion. Additional voltage regulator tuning was initiated. While performing the tuning, an abnormal voltageregulator response was observed when shifting to manual voltage control. Based on troubleshooting results, the transfer switch contacts were replaced. Tuning was recommenced on April 9, 2006, and was terminated when manual voltage control did not respond as expected.Subsequently, the DCCNP-2 manual voltage regulator card was replaced and voltage regulatortuning was successfully completed. A full load rejection test was performed on April 9, 2006, resulting in a maximum measured DG output voltage of 5042 volts. The voltage regulator was re-tuned and another full load rejection was performed. The maximum measured voltage was 5049 volts, again exceeding the acceptance criterion. After consulting with the vendor, the licensee determined that the regulator was functioning as designed and thatadditional tuning would have no impact on the ability to meet the acceptance criterion.

4.0TECHNICAL EVALUATION

The purpose of a full load rejection test as performed under SR 3.8.1.11 is to demonstrate thatthe DG is capable of rejecting a full load (90 percent to 100 percent of the DG continuous rating) without overspeed tripping or exceeding the predetermined voltage limits. The DG full load rejection may occur because of a system fault or inadvertent breaker tripping. This SRensures proper DG load response under the simulated test conditions. This test simulates the loss of the total connected load that the DG experiences following a full load rejection and verifies that the DG does not trip upon loss of the load. These acceptance criteria provide forDG damage protection. While the DG is not expected to experience this transient during the event, the SR requirements ensure that the DG is not degraded for future operation, includingre-connection to the bus if the trip initiator can be corrected or isolated. The existing 5000 volt limit in SR 3.8.1.11 is a standard industry value as indicated in NUREG-1431. This value wasincorporated in the DCCNP-1 and DCCNP-2 TS as part of the conversion to improved standardTS in September 2005. The licensee believed then that the 5000 volt limit would be readily achievable based on the 2004 testing. The previous TS did not specify a voltage limit for theDG full load rejection test SR.The licensee stated that the proposed amendment would increase the SR 3.8.1.11 limit on themaximum voltage following a DG full load rejection from a value 5000 volts to a value of 5350volts. The voltage overshoot following a full load rejection is a transient condition typically lasting for only a few seconds, with the peak voltage lasting for a much shorter period. The DG control components quickly reduce excitation and return voltage to its normal control point. The DG full load rejection tests show that the maximum voltage was present for approximately two cycles. Components subjected to these transient voltages include the generator, the cables that connectthe DG to the safety buses, the 4160-volt switchgear, and the DG control components. The licensee analyzed the effect of an increased voltage limit on these components as described below. 4.1GeneratorThe factory hi-potential (hi-pot) test value for the DG is 2E + 1000 volts for 60 seconds, where Eis the rated line to line voltage of the generator. The DCCNP-1 DGs are rated 4160 volts. Therefore, the factory ac hi-pot test value is 9320 volts. For initial field testing, the vendor recommends the test be conducted at 75 percent of this value or 6990 volts. After initial testing and generator service or repair, the vendor recommends a test value of 1.25E +500 volts. This equates to 5700 volts. In a telephone call on April 11, 2006, the NRC staff asked the licensee toprovide verification from the generator manufacturer that the generator would not experiencedetrimental effects due to transient voltages up to 5350 volts. In its April 12, 2006, response, the licensee stated that personnel have contacted General Electric Company (generator vendor)regarding the ability of the generator to withstand elevated voltage. The representative of GEstated that the transient overshoot voltage of 5350 volts that may be experienced every 18months does not adversely impact the generator. Based on the above, the NRC staff finds thatthe generators would not experience detrimental effects due to transient voltages up to 5350volts.4.2CablesCables used in the 4160-volt system at DCCNP-1 are rated at a nominal 5 kilovolts. ElectricPower Research Institute (EPRI) guidance for factory hi-pot tests recommends a 5-minute, 13-kilovolts test for 5-kilovolt-rated cables. The EPRI guidance indicates a typical maintenance hi-pot test value of 60 percent of the factory value, or 7800 volts. The DG control cable is rated at a minimum of 600 volts, which provides acceptable margin over the 163 volt value that would result from a DG voltage of 5700 volts. In a telephone call on April 11, 2006, the NRC staffasked the licensee to provide verification from the cable manufacturer that the 4160-volt cables would not experience detrimental effects due to transient voltages up to 5350 volts. In its April 12, 2006, response, the licensee stated that 5-kilovolt cables are manufactured by OkoniteCompany and have a 15 minute rating at 5500 volts. Based on the above, the NRC staff findsthat 5 kilovolt cables would not experience detrimental effects due to transient voltages up to 5350 volts. 4.3SwitchgearA review of industry standards applicable at the time DCCNP-1 was constructed, shows that theinsulation withstand capability of 4-kV-rated breakers significantly exceeds 5700 volts. Accordingly, the 4-kV breakers and switchgear are not limiting with respect to peak voltage during a full load rejection. In a telephone call on April 11, 2006, the NRC staff asked thelicensee to provide verification from the switchgear manufacturer that the 4-kV breakers and switchgear would not experience detrimental effects due to transient voltages up to 5350 volts.

In its April 12, 2006, response, the licensee stated that the switchgear is manufactured by AsiaBrown Boveri (ABB), and that ABB confirmed that there would be no adverse effect on the ability of the switchgear to operate following a voltage transient of 5350 volts for a shortduration. Accordingly, the NRC staff finds that the 4-kV breakers and switchgear would notexperience detrimental effects due to transient voltages up to 5350 volts.4.4Control ComponentsThe licensee determined that the most limiting control system component required to functionfor operation of the DG is the voltage regulator. The licensee's discussions with the vendordetermined that the voltage transient that would result from a short-term DG output voltage of5700 volts would not prevent the voltage regulator from fulfilling its safety function, although itsservice life could be shortened.In a telephone conference call on April 12, 2006, the NRC staff expressed its concern regardingproper operation of the DCCNP-2 DG with a new voltage regulator. On April 13, 2006, thelicensee provided additional information to satisfy the NRC staff's concern. The licensee statedthat it has conducted the following tests at the DCCNP-2 DGs incorporating a power factoradjustment to demonstrate proper operation of the voltage regulator. In its June 27, 2006, letter, the licensee stated that it does not intend to replace any voltage regulators on theDCCNP-1 DGs during the upcoming fall 2006 refueling outage; hence, the following information(in italics) is excerpted from the April 13, 2006, DCCNP-2 safety evaluation for information: Three Full Load Rejection TestsResults from all three tests, performed on both the installed and replacement voltageregulators, including those performed before optimum tuning, fall within approximately 2 percentof the peak voltage. After voltage regulator tuning, the results fall within approximately 1percent of the peak voltage. The licensee stated that these are repeatable results that providehigh confidence that the voltage regulator is performing as designed.Eight-Hour Load Power Factor Adjusted TestThis test was performed on the installed voltage regulator with the power factor between 0.80and 0.86. During initial power factor adjustment, and reactive load sharing during the run, the licensee indicated that all regulator responses were normal. Full Load Runs Reactive Load Minimized (Power Factor Maintained as Close as PossibleTo 1.0)These tests were performed on both the installed and replacement regulators. Although not atreduced power, 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).The licensee has also conducted the following tests to demonstrate proper operation of the newvoltage regulator.Fast Start TestProper voltage response was noted by the licensee during fast start tests on both the installedand replacement regulator.Half Load (1750 kilowatt) Reject TestsProper voltage response was observed during these tests on the replacement regulator.

The licensee indicated that voltage regulator response was assessed based on response of theabove tests. Performance during all these tests was consistent with that previously observed.

All of these tests provided indication of normal voltage regulator and governor response.During a conference call with the NRC staff on April 12, 2006, the licensee indicated that thedifficulty in meeting the full load rejection voltage limit is likely the result of not appropriately considering the effect of the power factor difference when selecting the SR values during the conversion to the improved standard technical specifications (STS) of NUREG-1431 inSeptember 2005. The conversion of the previous DG full load rejection TS SR to the improved STS of NUREG-1431 resulted in the addition of a limit for the power factor (0.86). This limitresulted in higher voltages following the full load rejection. Additionally, by a separate letter dated April 13, 2006, the licensee committed to perform all TSSR that challenge the operation of the Unit 2 AB emergency diesel generator voltage regulatorprior to Unit entering Mode 3 during the current refueling outage. By the June 27, 2006, letter,the licensee stated that all these tests were successfully completed. Based on the above, thestaff's concern is resolved.

On the basis of its review, the NRC staff agrees with the licensee that the proposed voltageovershoot limit during a full load rejection test once every 24 months would not adversely affect the generator, the cables that connect the DG safety buses, the 4160-volt switchgear, the DGcontrol components, or the capability of the DG to perform its intended safety function. TheNRC staff's determination is based on (1) the maximum voltage (5350 volts) during full loadrejection test lasts for approximately two cycles; (2) generator, cables and switchgear are tested(hi-pot) at much higher voltage with longer duration; (3) the voltage regulator will fulfill its safetyfunction per the vendor; and (4) manufacturers' confirmation that the generator, cables and switchgear would not have any adverse effect on performance due to transient voltage of up to 5350 volts for a short duration. 4.5Summary of EvaluationThe NRC staff has reviewed the licensee's submittal and finds that the proposed change forDCCNP-1 to increase the SR 3.8.1.11 limit on maximum voltage following a DG full loadrejection from a value of 5000 volts to a value of 5350 volts would not adversely affect thecapability of the DG to perform its intended safety function. The NRC staff also concludes thatthe proposed change conforms with acceptable standards as summarized in GDC 17 and GDC

18. The proposed amendment is, therefore, acceptable.

5.0STATE CONSULTATION

In accordance with the Commission's regulations, the Michigan State official was notified of theproposed issuance of the amendment. The State official had no comments.

6.0ENVIRONMENTAL CONSIDERATION

The amendment changes the requirements with respect to installation or use of a facilitycomponent located within the restricted area as defined in 10 CFR Part 20 or change the surveillance requirements. The staff has determined that the amendment involves nosignificant increase in the amounts, and no significant change in the types, of any effluents thatmay be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no publiccomment on such finding (71 FR 43534). Accordingly, the amendment meets the eligibilitycriteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b),

no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

7.0CONCLUSION

The NRC staff has concluded, based on the considerations discussed above, that: (1) there isreasonable assurance that the health and safety of the public will not be endangered byoperation in the proposed manner, (2) such activities will be conducted in compliance with theCommission's regulations, and (3) the issuance of the amendment will not be inimical to thecommon defense and security or to the health and safety of the public. Principal Contributors: A. Pal P. Tam

Date: September 1, 2006