ML061010512
| ML061010512 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/13/2006 |
| From: | Feintuch K Plant Licensing Branch III-2 |
| To: | Nazar M Indiana Michigan Power Co |
| Feintuch K. NRR/DORL (301) 415-3079 | |
| Shared Package | |
| ML061040176 | List: |
| References | |
| TAC MD1131 | |
| Download: ML061010512 (10) | |
Text
April 13, 2006 Mr. Mano K. Nazar Senior 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 2 (DCCNP-2) - ISSUANCE OF AMENDMENT UNDER EMERGENCY CIRCUMSTANCES REGARDING DIESEL GENERATOR VOLTAGE LIMIT REQUIREMENTS (TAC NO. MD1131)
Dear Mr. Nazar:
The Commission has issued the enclosed Amendment No. 276 to Facility Operating License No. DPR-74 for DCCNP-2. The amendment consists of changes to the Operating License in response to your application dated April 10, 2006, as supplemented by letters dated April 12 and 13 (two letters), 2006. The review and approval of this amendment was treated under emergency circumstances in accordance with Title 10 of the Code of Federal Regulations Section 50.91(a)(5).
The amendment revised Surveillance Requirement 3.8.1.11 of the DCCNP-2 Technical Specifications, 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 the Commission's next biweekly Federal Register notice.
Sincerely,
\\RA\\
Karl Feintuch, Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-316
Enclosures:
- 1. Amendment No. 276 to DPR-74
- 2. Safety Evaluation cc w/encls: See next page
Mr. Mano K. Nazar April 13, 2006 Senior 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 2 (DCCNP-2) - ISSUANCE OF AMENDMENT UNDER EMERGENCY CIRCUMSTANCES REGARDING DIESEL GENERATOR VOLTAGE LIMIT REQUIREMENTS (TAC NO. MD1131)
Dear Mr. Nazar:
The Commission has issued the enclosed Amendment No. 276 to Facility Operating License No. DPR-74 for DCCNP-2. The amendment consists of changes to the Operating License in response to your application dated April 10, 2006, as supplemented by letters dated April 12 and 13 (two letters), 2006. The review and approval of this amendment was treated under emergency circumstances in accordance with Title 10 of the Code of Federal Regulations Section 50.91(a)(5).
The amendment revised Surveillance Requirement 3.8.1.11 of the DCCNP-2 Technical Specifications, 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 the Commission's next biweekly Federal Register notice.
Sincerely,
\\RA\\
Karl Feintuch, Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-316
Enclosures:
- 1. Amendment No. 276 to DPR-74
- 2. Safety Evaluation cc w/encls: See next page DISTRIBUTION PUBLIC GHill, OIS LPL3-1 R/F RidsOGCRp RidsNrrLATHarris RidsNrrPMPTam RidsNrrPMKFeintuch RidsDorlDpr RidsNrrDirsltsb RidsAcrsAcnwMailCenter APal RidsRgn3MailCenter Package Accession Number: ML061040176 Amendment Accession Number: ML061010512 TS Page Accession Number: ML061040402 OFFICE NRR:LPL3-1/PM NRR:LPL3-1/LA NRR:EEEB/BC(A)
OGC NRR:LPL3-1/BC NAME KFeintuch THarris EBrown*
AHodgdon PTam for LRaghavan DATE 4/13/06 4/13/06 4/13/06 4/13/06 4/13/06 OFFICIAL RECORD COPY
- Safety evaluation transmitted by memo of 4/13/06.
Donald C. Cook Nuclear Plant, Units 1 and 2 cc:
Regional Administrator, Region III U.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Attorney General Department of Attorney General 525 West Ottawa Street Lansing, MI 48913 Township Supervisor Lake Township Hall P.O. Box 818 Bridgman, MI 49106 U.S. Nuclear Regulatory Commission Resident Inspector's Office 7700 Red Arrow Highway Stevensville, MI 49127 James M. Petro, Jr., Esquire Indiana Michigan Power Company One Cook Place Bridgman, MI 49106 Mayor, City of Bridgman P.O. Box 366 Bridgman, MI 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, MI 48909 Mr. John A. Zwolinski Safety Assurance Director Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106 Michigan 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 48909-7741 Lawrence J. Weber, Plant Manager Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106 Mr. Joseph N. Jensen, Site Vice President Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106
INDIANA MICHIGAN POWER COMPANY DOCKET NO. 50-316 DONALD C. COOK NUCLEAR PLANT, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 276 License No. DPR-74 1.
The U.S. Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Indiana Michigan Power Company (the licensee) dated April 10, 2006, as supplemented by letters dated April 12 and 13 (two letters), 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 amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Facility Operating License as indicated in the attachment to this license amendment.
3.
This license amendment is effective as of its date of issuance and shall be implemented immediately.
FOR THE NUCLEAR REGULATORY COMMISSION
\\RA by P. Tam\\
L. Raghavan, Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Operating License Date of Issuance: April 13, 2006
ATTACHMENT TO LICENSE AMENDMENT NO. 276 FACILITY OPERATING LICENSE NO. DPR-74 DOCKET NO. 50-316 Replace the following page of Facility Operating License No. DPR-74 with the attached revised page. The change area is identified by a marginal line.
REMOVE INSERT 3.8.1-10 3.8.1-10
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 276 TO FACILITY OPERATING LICENSE NO. DPR-74 INDIANA MICHIGAN POWER COMPANY DONALD C. COOK NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-316
1.0 INTRODUCTION
By application to the U.S. Nuclear Regulatory Commission (NRC, Commission) dated April 10, 2006, as supplemented by letters dated April 12 and 13 (two letters), 2006, 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 revise Surveillance Requirement (SR) 3.8.1.11 of the Technical Specifications (TSs), changing the AB diesel generator (DG) load rejection voltage limit from
- 5000 volts to #5350 volts.
The licensee requested that the application for DCCNP-2 be processed under emergency circumstances; accordingly, this safety evaluation pertains only to the NRC staff's review of the DCCNP-2 amendment. The application for DCCNP-1 will be addressed in a future issuance tracked under TAC NO. MD1130.
2.0 REGULATORY 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 Design Criteria 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 systems to permit the functioning of structures, systems, and components that are important to safety.
The onsite system is required to have sufficient independence, redundancy, and testability to perform its safety function, assuming a single failure. The offsite power system is required to be 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
- DCCNP-2 was constructed before promulgation of the General Design Criteria in 10 CFR Part 50. The NRC staff used the GDCs in this safety evaluation solely as a convenient summary of acceptable standards.
to minimize the probability of losing electric power from the remaining electric power supplies as a result of loss of power from the unit, the offsite transmission network, or the onsite power supplies.
GDC-18, Inspection and testing of electric power systems, requires that electric power systems that are important to safety must be designed to permit appropriate periodic inspection and testing.
10 CFR 50.36, Technical Specifications, requires a licensees TS to establish Limiting Conditions of Operation (LCOs) and SRs for equipment that is required for safe operation of the facility.
3.0 BACKGROUND
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 full load rejection, i.e., rejection of a load greater than or equal to ($) 3150 kilowatts (kW) and
- 3500 kW. The basis for the 5000 volt limit is DG damage protection. During a performance of SR 3.8.1.11 for the Unit 2 AB DG on March 26, 2006, the maximum measured voltage was 4993 volts. Adding the 55 volts instrument uncertainty margin to the measured values resulted in a test value, 5048 volts, which exceeded the 5000 volt TS criterion.
The licensee replaced the voltage regulator and tuned it to optimize the system response. 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 voltage regulator 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 manual voltage regulator card was replaced and voltage regulator tuning 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, it was determined that the regulator was functioning as designed and that additional tuning would have no impact on the ability to meet the acceptance criterion.
4.0 TECHNICAL EVALUATION
The purpose of a full load rejection test as performed under SR 3.8.1.11 is to demonstrate that the 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 SR ensures 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 for DG 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, including re-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 was incorporated in the DCCNP-2 TS as part of the conversion to improved standard TS 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 the DG full load rejection test SR.
The licensee stated that the proposed amendment would increase the SR 3.8.1.11 limit on the maximum voltage following a DG full load rejection from a value #5000 volts to a value of #5350 volts. 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 connect the 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.
4.1 Generator The factory hi-potential (hi-pot) test value for the DG is 2E + 1000 volts for 60 seconds, where E is the rated line to line voltage of the machine. The DCCNP-2 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 to provide verification from the generator manufacturer that the generator would not experience detrimental 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 GE stated that the transient overshoot voltage of 5350 volts that may be experienced every 18 months does not adversely impact the generator. Based on the above, the NRC staff finds that the generators would not experience detrimental effects due to transient voltages up to 5350 volts.
4.2 Cables Cables used in the 4160-volt system at DCCNP-2 are rated at a nominal 5 kilovolts. Electric Power 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 which would result from a DG voltage of 5700 volts. In a telephone call on April 11, 2006, the NRC staff asked 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 Okonite Company and have a 15 minute rating at 5500 volts. Based on the above, the NRC staff finds that 5 kilovolt cables would not experience detrimental effects due to transient voltages up to 5350 volts.
4.3 Switchgear A review of industry standards applicable at the time DCCNP-2 was constructed shows that the insulation 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 the licensee 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 Asia Brown Boveri (ABB), and 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 short duration. The NRC staff finds that the 4-kV breakers and switchgear would not experience detrimental effects due to transient voltages up to 5350 volts.
4.4 Control Components The licensee determined that the most limiting control system component required to function for operation of the DG is the voltage regulator. The licensee's discussions with the vendor determined that the voltage transient that would result from a short-term DG output voltage of 5700 volts would not prevent the voltage regulator from fulfilling its safety function, although its service life could be shortened.
In a telephone conference call on April 12, 2006, the NRC staff expressed its concern regarding proper operation of the DG with a new voltage regulator. On April 13, 2006, the licensee provided additional information to satisfy the NRC staffs concern. The licensee stated that it 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. The licensee stated that these are repeatable results that provide high confidence that the voltage regulator is performing as designed.
Eight-Hour 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, the licensee indicated that all regulator responses were normal.
Full Load Runs 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, 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 new voltage regulator.
Fast Start Test Proper voltage response was noted by the licensee 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.
The licensee indicated that voltage regulator response was assessed based on response of the above 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 the difficulty 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 in September 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 limit resulted in higher voltages following the full load rejection.
Additionally, by a separate letter dated April 13, 2006, the licensee committed to perform all TS SR that challenge the operation of the Unit 2 AB emergency diesel generator voltage regulator prior to Unit entering Mode 3 during the current refueling outage. Based on the above, the staffs concern is resolved.
On the basis of its review, the NRC staff agrees with the licensee that the proposed voltage overshoot 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 DG control components, or the capability of the DG to perform its intended safety function. The NRC staffs determination is based on (1) the maximum voltage (5350 volts) during full load rejection test lasts for approximately two cycles; (2) generator, cables and switchgear are tested (hi-pot) at much higher voltage with longer duration; (3) voltage regulator will fulfill its safety function 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.
4.5 Summary of Evaluation The NRC staff has reviewed the licensees submittal and finds that the proposed change for DCCNP-2 to increase the SR 3.8.1.11 limit on maximum voltage following a DG full load rejection from a value of #5000 volts to a value of #5350 volts would not adversely affect the capability of the DG to perform its intended safety function. The NRC staff also concludes that the proposed change conforms with acceptable standards as summarized in GDC 17 and GDC
- 18. The proposed amendment is, therefore, acceptable.
5.0 EMERGENCY CIRCUMSTANCES The NRCs regulation at 10 CFR 50.91(a)(5) contains provisions for issuance of an amendment where the Commission finds that emergency circumstances exist, in that a licensee and the Commission must act quickly and that time does not permit the Commission to publish a Federal Register notice allowing 30 days for prior public comment. The emergency exists in this case in that the proposed amendment is needed to allow the licensee to resume operation after the current refueling shutdown. The NRC staff has determined that the licensee used its best efforts to make a timely application and that the licensee could not reasonably have foreseen the problem that led to this license change request.
According to the licensee, the emergency situation resulted from the unexpectedly high voltage following a full load rejection during performance of an SR with the reactor defueled for a scheduled refueling outage. Successful completion of the SR is required to establish operability of the AB DG. The CD DG was previously removed from service to perform required inspection and maintenance. Operability of the AB DG is required, in accordance with TS 3.8.2, to commence the fuel movements needed to reload fuel into the DCCNP-2 reactor. These fuel movements were planned to commence the morning of April 12, 2006. Thus, these fuel movements are on the critical path for restoring DCCNP-2 to operation. Neither a routine nor an exigent amendment can be processed prior to April 12, 2006. Therefore, the licensee requested an amendment under emergency circumstances to allow resumption of DCCNP-2 operation.
The licensee stated that failure of the AB DG to maintain voltage #5000 volts following a full load rejection was unexpected since voltage had remained below this value during previous full load rejection tests of all four DCCNP-1 and DCCNP-2 DGs.
6.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commissions regulation at 10 CFR 50.92(c) states that the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) result in a significant reduction in a margin of safety.
7.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendment. The State official had no comments.
8.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has made a final finding that the amendment involves no significant hazards consideration. Accordingly, the amendment meets the eligibility criteria 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.
9.0 CONCLUSION
The NRC staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: A. Pal K. Feintuch Date: April 13, 2006