ML12122A986

Issuance of Amendment Proposed Technical Specification Amendment to Modify Technical Specification 3.8.1, AC Sources - Operating Surveillance Requirements

ML12122A986
Person / Time
Site:	Clinton
Issue date:	05/22/2012
From:	Joel Wiebe Plant Licensing Branch III
To:	Pacilio M Exelon Generation Co
Wiebe J
References
TAC ME6876
Download: ML12122A986 (16)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 22, 2012 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 SUB~IECT: CLINTON POWER STATION, UNIT NO.1 - ISSUANCE OF AMENDMENT RE: PROPOSED TECHNICAL SPECIFICATION AMENDMENT TO MODIFY TECHNICAL SPECIFICATION 3.8.1, hAC SOURCES - OPERATING" SURVEILLANCE REQUIREMENTS (TAC NO. ME6876)

Dear Mr. Pacilio:

The U.S. Nuclear Regulatory Commission (the Commission) has issued the enclosed Amendment No. 199 to Facility Operating License No. NPF-62 for the Clinton Power Station, Unit NO.1. The amendment is in response to your application dated August 15, 2011, as supplemented by letter dated February 13, 2012.

The amendment requested a revision to the Limiting Condition for Operation 3.8.1, HAC Sources

- Operating," through a reduction to the maximum steady state voltage criteria for safety-related 4.16 kV buses from 4580 V to 4300 V in certain Technical Specifications (TSs), Section 3.8.1, Surveillance Requirements.

A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.

Sincerely,

~

\ 'lIthq/) A~Lv jJoel S. Wiebe, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-461

Enclosures:

1. Amendment No. 199 to NPF-62

2. Safety Evaluation cc w/encls: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 EXELON GENERATION COMPANY, LLC DOCKET NO. 50-461 CLINTON POWER STATION, UNIT NO.1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 199 License No. NPF-62

1. The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by Exelon Generation Company, LLC (the licensee), dated August 15, 2011, as supplemented by letter dated February 13, 2012, 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;

8. 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 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 Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-62 is hereby amended to read as follows:

-2 (2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 199, are hereby incorporated into this license. Exelon Generation Company shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of its date of issuance and shall be implemented within 30 days of the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION J~~L :80. Chief Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications and Facility Operating License Date of Issuance:

ATTACHMENT TO LICENSE AMENDMENT NO. 199 FACILITY OPERATING LICENSE NO. NPF-62 DOCKET NO. 50-461 Replace the following pages of the Facility Operating License and Appendix "A" Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove License NPF-62 License NPF-62 Page 3 Page 3 TSs TSs 3.8-4 3.8-4 3.8-6 3.8-6 3.8-8 3.8-8 3.8-9 3.8-9 3.8-11 3.8-11 3.8-14 3.8-14 3.8-15 3.8-15

AC Sources 3.8.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME G. Three or more required G.1 Enter LCO 3.0.3. Immediately AC sources inoperable.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.1.1 Verify correct breaker alignment and In accordance indicated power availability for each with the offsite circuit. Surveillance Frequency Control Program SR 3.8.1. 2 -------------------NOTES------------------

1. Performance of SR 3.8.1.7 satisfies this SR.

2. All DG starts may be preceded by an engine period and followed by prior to loading.

3. A modified DG start involving and gradual acceleration to synchronous may be used for this SR as recommended by the manufacturer.

When modified start procedures are not used, the time, voltage, and tolerances of SR 3.8.1.7 must be met.

Verify each DG starts from standby In accordance conditions and achieves steady state with the voltage ~ 4084 V and s 4300 V and frequency Surveillance

~ 58.8 Hz and ~ 61.2 Hz.

Frequency Control Program (continued)

CLINTON 3.8-4 Amendment No. 199

AC Sources--Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.7 -------------------NOTE-----------------

All DG starts may be by an engine period.

Veri each DG starts from standby In accordance condition and achieves: with the Surveillance

a. In ~ 12 seconds, ~ 4084 V and Frequency Control Program frequency ~ 58.8 Hz; and

b. state voltage ~ 4084 V and

~ 4300 V and frequency ~ 58.8 Hz and

~ 61.2 Hz.

SR 3.8.1. 8 ------------------NOTE-------------------

This Surveillance shall not be performed in MODE 1 or 2 (not applicable to Division 3 AC sources). However, credit may be taken for unplanned events that satisfy this SR.

automatic and manual transfer of In accordance unit power supply from the normal offsite with the circuit to the alternate offsite circuit. Surveillance Frequency Control Program (continued)

CLINTON 3.8-6 Amendment No. 199

AC Sources-Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.11 -------------------NOTES------------------

1. All DG starts may be by an engine period.

2. This Surveillance shall not be performed in MODE 1, 2, or 3 (not icable to the Division 3 DG) .

However, credit may be taken for unplanned events that satisfy this SR.

on an actual or simulated loss of In accordance offsite power signal: with the Surveillance Frequency Control Program

a. De-energization of emergency buses;

b. Load shedding from emergency buses for Divisions 1 and 2; and

c. DG auto-starts from standby condition and:

1. zes permanently connected loads in :0; 12 seconds,

2. energizes auto-connected shutdown loads,

3. maintains steady state voltage

~ 4084 V and :0; 4300 V,

4. maintains state frequency 58.8 Hz and:O; 61.2 Hz, and

5. supplies permanently connected and auto-connected shutdown loads for

~ 5 minutes.

(continued)

CLINTON 3.8-8 Amendment No. 199

AC Sources-Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.:'2 -------------------NOTES------------------

1. All DG starts may be preceded by an engine period.

2. This Surveillance shall not be performed in MODE 1 or 2 (not applicable to the Division 3 DG).

However, credit may be taken for unplanned events that satisfy this SR.

Verify on an actual or simulated Emergency In accordance Core Cooling System (ECCS) initiation with the signal each DG auto-starts from standby Surveillance condition and: Frequency Control Program

a. In S 12 seconds after auto-start and during tests, achieves voltage ~ 4084 V and ~58.8 Hz;

b. Achieves state voltage ~ 4084 V and S 4300 V and frequency ~ 58.8 Hz and S 61.2 Hz; and

c. Operates for 2 5 minutes.

SR 3.8.1.13 ------------------NOTE-------------------

Credit may be taken for unplanned events that satisfy this SR.

Verify each DG's automatic trips are In accordance bypassed on an actual or simulated ECCS with the initiation except: Surveillance Frequency

a. Engine Control Program

b. Generator differential current; and

c. Overcrank for DG 1A and DG lB.

(continued)

CLINTON 3.8-9 Amendment No. 199

AC Sources-Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FR::!:QUENCY SR 3.8.1.15 ----------------------NOT::!:---------------

1. This Surveillance shall be performed within 5 minutes of shutting down the DG after the DG has ~ 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> loaded ~ 3482 kW for DG lA, ~ 3488 kW for DG lE, and ~ 1980 kW for DG 1C.

Momentary transients outside of the load range do not invalidate this test.

2. All DG starts may be preceded by an prelube Verify each DG starts and achieves: In accordance with the

a. In S 12 seconds, voltage ~ 4084 V and Surveillance Frequency frequency ~ 58.8 Hz and Control Program

b. state ~ 4084 V and S 4300 V and frequency ~ 58.8 Hz and S 61.2 Hz.

(continued)

CLINTON 3.8-11 Amendment No. 199

AC Sources-Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.19 -------------------NOTES------------------

1. All DG starts may be by an engine prelube period.

2. This Surveillance shall not be performed in MODE 1, 2, or 3 (not applicable to the Division 3 DG).

However, credit may be taken for unplanned events that this SR.

Verify, on an actual or simulated loss of In accordance offsite power signal in conjunction with an with the actual or simulated ECCS initiation Surveillance Frequency

a. De-energization of emergency buses; Control Program

b. Load shedding from emergency buses for Divisions 1 and 2; and

c. DG auto-starts from condition and:

1. energizes connected loads in s 12 seconds,

2. energizes auto-connected emergency loads,

3. achieves steady state voltage

~ 4084 V and s 4300 V,

4. achieves steady state frequency

~ 58.8 Hz and S 61.2 Hz, and

5. supplies permanently connected and auto-connected emergency loads for

~ 5 minutes.

(continued)

CLINTON 3.8-14 Amendment No. 199

AC 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.20 -------------------NOTE-------------------

All DG starts may be by an engine prelube period.

Verify, when started simultaneously from In accordance standby condition, each DG achieves: with the Surveillance

a. In S 12 seconds, 2 4084 V and Frequency Control Program frequency 2 58.8 Hz; and

b. Steady state 4084 V and S 4300 V and 2 58.8 Hz and S 61.2 Hz.

CLINTON 3.8-15 Amendment No. 199

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 199 TO FACILITY OPERATING LICENSE NO. NPF-62 EXELON GENERATION COMPANY, LLC CLINTON POWER STATION, UNIT NO.1 DOCKET NO. 50-461 By letter to the U.S. Nuclear Regulatory Commission (NRC, the Commission) dated August 15, 2011 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML112280256 ), as supplemented by letter dated February 13, 2012 (ADAMS Accession No. ML12045A069), Exelon Generation Company, LLC (the licensee) requested changes to the technical specifications (TSs) for Clinton Power Station, Unit No.1 (CPS). The proposed changes would revise the maximum steady-state voltage criteria of TS Limiting Condition for Operation (LCO) 3.8.1, "AC Sources - Operating," for safety-related 4.16 kV buses from 4580 V to 4300 V.

The February 13, 2012, supplemental letter contained clarifying information and did not change the NRC staff's initial proposed finding of no significant hazards consideration.

2.0 REGULATORY EVALUATION

The staff used the following NRC requirements and guidance documents to review the license amendment request (LAR):

Part 50 of Title 10 of the Code of Federal Regulations (10 CFR) requires that TSs shall be included by applicants for a license authorizing operation of a production or utilization facility.

10 CFR 50.36(c) requires that TSs include items in five specific categories related to station operation. These categories are (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operations (LCOs); (3) surveillance requirements (SRs); (4) design features; and (5) administrative controls. The proposed changes to TS, discussed in this safety evaluation, are within the SRs category.

Regulatory Guide (RG) 1.9, Revision 3, "Selection, Design, Qualification, and Testing of Emergency Diesel Generator (EDG) Units used as Class 1E Onsite Electric Power Systems at Nuclear Power Plants," provides certain recommendations for EDG design and testing, which in general are used as guidance to develop the SRs for the EDGs.

Enclosure

-2

3.0 TECHNICAL EVALUATION

The NRC staff has reviewed the licensee's regulatory and technical analyses in support of its proposed license amendment which are described in Section 3.0 of the licensee's submittal.

The detailed evaluation below will support the conclusion 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.

3.1 Background According to the CPS updated final safety analysis report (UFSAR), Section 8.1.2, the station is provided with offsite power from 138 kilovolt (kV) and 345 kV transmission systems. An Emergency Reserve Auxiliary Transformer (ERAT) transforms the electrical power from 138 kV to the 4160 V emergency auxiliary bus Voltage. The 345 kV transmission system feeds Reserve Auxiliary Transformers (RATs) A, B, and C, which in turn transform the electrical power to the 6900 V and 4160 V auxiliary bus voltages.

According to UFSAR, Section 8.3, the onsite alternating current (ac) power system consists of unit auxiliary (non-Class 1E) and unit Class 1E power systems. The unit auxiliary 6900 V and 4160 V buses are primarily fed from the two unit auxiliary transformers (UATs) 1A and 1B. The secondary source of these buses are three RATs A, B, and C. The onsite Class 1E AC power system includes three 4160V Class 1E divisions/buses, each provided with an EDG. One of the offsite power sources for Class 1E divisions/buses is the RAT B, and the other is the ERAT.

Each EDG set is automatically started based on the following events: (1) associated bus voltage when fed from either of the offsite power sources falls below the preset value [loss of voltage];

(2) reactor low water level; (3) high drywell pressure; or (4) associated bus second level undervoltage falls below the preset value (degraded voltage condition). After each EDG set accelerates to approximately rated frequency and voltage, its breaker automatically closes if normal offsite ac power is not available, and the EDG is sequentially loaded. In UFSAR, Section 8.3.1.2.2, under a paragraph regarding conformance to RG 1.9, it is stated that during the loading sequence, each EDG has the capability of frequency restoration to within 2 percent (%)

of nominal and voltage restoration to within 10% of nominal within 2 seconds after loading is applied, which is within 60% of the load sequence time interval.

3.2 Evaluation of Proposed Change to Maximum Steady-State Voltage Criteria In the LAR, the licensee stated that a review of TS Section 3.8.1 was performed and concluded that the maximum steady state voltage limit specified in TS SR's 3.8.1.2, 3.8.1.7, 3.8.1.11, 3.8.1.12, 3.8.1.15, 3.8.1.19, and 3.8.1.20 is non-conservative with respect to existing design basis analyses for certain 120 V ac safety-related components. Therefore, the licensee performed an Operability Evaluation (OE) in accordance with NRC Administrative Letter 98-10, "Dispositioning of Technical Specifications that are insufficient to assure plant safety." The OE concluded that the TS SRs associated with maximum steady-state voltage for EDGs involve an improper or inadequate TS value, and considered this issue a degraded or non-conforming

- 3 condition. Therefore, consistent with the NRC Administrative Letter 98-10, the licensee implemented administrative controls as a short term corrective action.

To correct the issue, the licensee proposed to revise the TS to reduce the maximum steady state voltage limit for EDGs from 4580 V to 4300 V, as described in the SR's 3.8.1.2, 3.8.1.7, 3.8.1.1:1, 3.8.1.12, 3.8.1.15, 3.8.1.19, and 3.8.1.20.

In response to a staff question, regarding the basis for an EDG voltage of 4300 V instead of 4580 V currently specified in TS, the licensee in a letter dated February 13, 2012, stated that based on its engineering calculation, it was derived that EDGs should have a maximum steady state voltage of 4300 V to prevent an overvoltage condition on the 120 V equipment. Therefore, the TS maximum allowable value of 4580 V was found to be non-conservative.

In response to another staff question regarding the basis of the maximum acceptable voltage limits on the 4.16 kV safety-related buses as 4454 V for 30 minutes, and 4300 V for continuous operation as stated in the LAR, the licensee in a letter dated February 13, 2012, provided the following clarification:

A Static VAR [volt amperes reactive] Compensator (SVC) is located on the 4.16 kV side of the RAT [B] and ERAT. The SVCs provide voltage support by varying the reactive load on the bus.

The maximum voltage for both offsite sources is 105 percent of rated voltage. When an offsite source voltage is high, the associated transformer SVC actively maintains the 4.16 kV bus at a lower value than would be expected without the SVC. If an SVC trips off-line while the 345 kV source is at the maximum 105 percent voltage, the voltage on the secondary side of RAT would reach 4454 V due to the transformer tap ratio. However, in the case of the 138 kV off-site source, a 105% maximum voltage would produce less than 4454 V on the secondary side of ERAT. Therefore, the RAT secondary voltage is the bounding case. The basis for 4454 V for 30 minutes is the maximum bus voltage that can be expected if the RAT SVC trips concurrent with 345 kV offsite voltage at 105 percent. It is expected that the licensee will reduce the voltage or transfer to the ERAT within 30 minutes. The steady state voltage limit of 4300 V will prevent component damage at the 120 V level at no load or lightly loaded conditions.

Based on the information provided, the staff finds the licensee response acceptable.

The staff requested the licensee to provide the maximum instrument voltage uncertainty considered to derive the TS EDG voltage limits. In a letter dated February 13, 2012, the licensee responded that the uncertainty considered is the same for Divisions 1, 2, and 3. For calibration purposes, test instrument uncertainties as well as voltage regulator uncertainties are considered to derive the allowable range for EDG output voltage. The test instrument uncertainty of plus (+) 21 V is applied to the lower limit of 4084 V and minus (-) 8 V is applied to the upper limit of 4300 V. The uncertainty due to the voltage regulator is plus/minus (+/-) 21 V.

Therefore, the allowable calibration band for the voltage regulator is 4126 V (Le., 4084 V + 21 V

+ 21 V) to 4271 V (Le., 4300 V - 8 V - 21 V). This calibration band for the voltage regulator ensures that the EDGs are operated within the TS limits of 4084 V and 4300 V. Based on this information, the staff finds the licensee has adequately considered the instrument voltage uncertainty to derive the TS EDG steady-state voltage limits.

-4 Additionally, the staff requested the licensee to provide a discussion of the voltage profile for the 4160 V safety-related buses when powered by the EDGs during the sequencing of large safety related loads, based on analysis or test. The licensee in a letter dated February 13, 2012, responded that the voltage profiles recorded for all three divisions from the integrated tests conducted in December 2011, demonstrated that the Division 1 EDG output voltage stabilized at approximately 4220 V, the Division 2 EDG output voltage stabilized at approximately 4230 V, and the Division 3 EDG output voltage stabilized at approximately 4140 V. This is acceptable to the staff as the voltages for all three EDGs stabilized below 4300 V following the sequencing of major safety-related loads.

Based on the review of the August 15, 2011, LAR and the responses provided by the licensee in a letter dated February 13, 2012, the NRC staff finds that the proposed EDG maximum steady state voltage limit is more restrictive, and meets the intent of RG 1.9, Revision 3. The EDGs will continue to provide adequate voltage to the safety-related loads and mitigate accidents as described in the UFSAR. Therefore, the staff finds the changes acceptable.

4.0 STATE CONSULTATION

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

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes requirements with respect to installation or use of a facility's components located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may 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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (76 FR 64391; October 18, 2011). Accordingly, the amendments meet 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 amendments.

6.0 CONCLUSION

The Commission 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Swagata Som, NRR Date of issuance:

May 22,2012 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

CLINTON POWER STATION, UNIT NO.1 - ISSUANCE OF AMENDMENT RE: PROPOSED TECHNICAL SPECIFICATION AMENDMENT TO MODIFY TECHNICAL SPECIFICATION 3.8.1, "AC SOURCES - OPERATING" SURVEILLANCE REQUIREMENTS (TAC NO. ME6876)

Dear Mr. Pacilio:

The U.S. Nuclear Regulatory Commission (the Commission) has issued the enclosed Amendment No. 199 to Facility Operating License No. NPF-62 for the Clinton Power Station, Unit No.1. The amendment is in response to your application dated August 15, 2011, as supplemented by letter dated February 13, 2012.

The amendment requested a revision to the Limiting Condition for Operation 3.8.1, "AC Sources

- Operating," through a reduction to the maximum steady state voltage criteria for safety-related 4.16 kV buses from 4580 V to 4300 V in certain Technical Specifications (TSs), Section 3.8.1, Surveillance Requirements.

A copy of the Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.

Sincerely, I RA I Joel S. Wiebe, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-461

Enclosures:

1. Amendment No. 199 to NPF-62

2. Safety Evaluation cc w/encls: Distribution via Listserv DISTRIBUTION:

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