ML20198L870
| ML20198L870 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 01/14/1998 |
| From: | Tulon T COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20198L875 | List: |
| References | |
| NUDOCS 9801160139 | |
| Download: ML20198L870 (8) | |
Text
Cnmmonwealti filnon Company ~
litaniwenxl C<ncrating Stepon Route
- l, llox 8 i lirxesik II (4607%I9
.Tel 8t%4%%01 January 14,1998 United States Nuclear Regulatory Commission Washington, D.C. 20555-0001 Attention:
Docutaent Control Desk
SUBJECT:
Application for Am' ament to Appendix A, Technical Specifications, for Facility Operating Licenses Braidwood Nuclear Power Station Units 1 and 2 Facility Operating Licenses NPF-72 and NPF-77 NRC Docket Nos. 50456 and 50-457
" Electrical Power Systems, D.C. Sources" Pursuant to 10 CFR 50.90 Commonwealth Edison Company (Comed) proposes to amend Appendix A, Technical Specifications for Biaidwood Units 1 and 2. Comed proposes to revise Technical Specifications Section 3/4.8.2, D.C. Sources, and its Bases to allow replacement of the 125 volt DC AT&T batteries with new Charter Power Systems, Inc.
(C&D) batteries. In addition, the crosstie !oading limitation is revised to reflect the larger capacity of the C&D batteries.
The amendment request contists of the following:
Attachment A: Description and Safety Analysis Of Proposed Changes To Appendix A Technical Specifications Of Facility Operating Licenses NPF-72 and NPF-77 l
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Document Control Desk January 14,1998 Page 2
- Attachment B: Marked Up Pages For Proposed Changes To Appendix A Technical Specifications Of Facility Operating Licenses NPF-72 and NPF-77 Attachment C: Evaluation Of SigniGcant Hazards Consideration For Proposed Changes To Appendix A Technical Specifications Of Facility Operating Li:enses NPF-72 and NPF-77 Attachment D: Environmental Assessment For Proposed Changes To Appendix A Technical Specifications Of Facility Operating Licenses NPF-72 and NTF-77 The proposed changes have been reviewed and ' approved by the On-site and Off-site Review Committees in accordance with Comed procedures. Comed has reviewed this proposed amendment in accordance with 10 CFR 50.92(c) and has determined that no significant hanrds consideration exists.
Comed is notifying the State ofIllinois of our application for this amendment by transmitting a copy of this letter and the associated attachments to the designated State Oflicial.
- Comed requests that the NRC Staffreview and approve this amendment request by
- August 5,1998 to support replacement of the battery during the Unit I refueling outage scheduled to begin on September 5,1998.
T o the best of my knowledge and belief, the statements contained in this document are true and correct. In some respects, these statements are not based on my personal knowledge, but on information fuinished by other Comed employees, contractor employees, and/or consultants.. Such information has been reviewed in accordance with company practice, and I believe it to be reliable.
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Document Control Desk January 14,1998 Page 3 Please address any cornments or questions regarding this matter to our Nuclear Licensing Department.
Sincere ly, AWM Ti g iy J. Tulon S e'Vice President Braidwood Nuclear Generating Station Subscribed and sworn to before me this bday of T4
,1999.
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OFFICIAL SEAL Notary Public
}l MICHELLE A TURNBULL 3:
$ll_* Coff'88'?f,E5?"E8 059,23,tjll NOTARY PUBUC,8 TATE OMuwols Attachments n.n m oo m u cc:
NRC Regional Administrator - Rill Braidwood Project Manager - NRR Senior Resident inspector - Brt!dwood Office of Nuclear Safety -IDNS
ATTACHMENT A DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CilANGES TO APPENDIX A TECilNICAL SPECIFICATIONS OF FACILITY OPERATING LICENSEF NPF-72 AND NPF-77 A.
SUMM ARY DESCRIPTION OF TIIE PROPOSED CIIANGES Commonwealth Edison (Comed) proposes to revise Section 3/4.8.2, "D.C. Sources", and its Bases Section of the Technical Specifications for Braidwood Station. Since the AT&T batteries are not considered optimal for Nuclear operations, the proposed change will allow replacement of the installed 125 volt DC AT&1 batteries with new 125 volt DC Charter Power Systems, Inc. (C&D) batteries. In addition, the crosstie loading limitation is revised to reficct the increased capacity of the replacement C&D batteries and all references to Gould batteries have been removed since the Current Technical Specifications (CTS) did not need to be updated when the last Gould batteries were removed. The mrked up Technical Specification pages are provided in Attachment B.
II.
DESCRIPTION AND BASES OF Tile CURRENT REQUIREMENTS CTS 3/4.8.2,"D.C. Sources", provides parameters for Gould and AT&T batteries, including total battery terminal voltage. Table 4.8-2 provides battery Surveillance Requirements (SR) for both the Gouli and AT&T batter:es, including specific gravity and battery charging current. These requirements provide assurance that the batteries are capable of p rforming their design function.
.).2.e identifies that a modified performance discharge test can be used for the AT&T batteries to demonstrate battery capacity. This test is described in IEEE Standard 450-1995, "lEEE Recommended Practice for Maintenance, Testing, and Replxement of Vented Lead-Acid Batteries for Stationary /$pplication."
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In addition. CTS Act ons 3.8.2.t.c and 3.8.2.2.b provide a load restriction while a battery is i
crosstied to the opposite unit. Verifying the crosstie loading limits ensures that the OPERABLE battery will have sufficient capacity to energize the design basis for is ofits DC bus while maintaining the limited DC loals of the inoperable DC bus on a shutdown unit.
The DC electrical pcwer system provides the DC emergency power system with control power. During plant operation, the OPERABILITY of the AC and EC power sources and associated distribution systems ensures sufficient power will be available to supply the safety-related equipment for: (1) the safe shutdown of the facility; and (2) the mitiption and control i
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of accident conditions viithin the facility. These conditions are consistent with the initial condition assumptions of the safety analyses and are based on maintaining at least one division of AC and DC power sources and asswiated distribution system operational during accident conditions coincident with an assumed Loss Of Offsite Power (LOOP) n "it and a single failure of the redundant division.
During shutdown and refueling, the OPERABILITY of the AC and DC power sources and associated distribution systems ensure tha:: (1) the facility can be maintained in the shutdown or refueling condition; and (2) sufficient instrumentation and control capability are available for monitoring and maintaining the unit in such condition.
C.
DESCRIPTION AND llASES OF Tilh REQUESTED REVISIONS Comed will replace the installed 125 volt DC AT&T batteries with new 125 volt DC C&D batteries.
Chances to the CTS Since the Gould batteries have all been replaced by AT&T batteries, all of the references to the Gould batteries are removed. In cases where the parameters for the new C&D batteries are the same as the installed AT&T batteries, references to the Gould batteries are simply delet:d. These include references in SR 4.8.2.1.2.e and in a footnote to 4.8.2.1.2.b.2 and 4.8.2.1.2.c.3. These changes are editorial because the Gould batteries are no longer installed and there are other requirements that ensure the installed ( AT&T) batteries are capable of performing their design ftmetion.
In addition, changes are proposed to CTS Section 3/4.8.2,"DC Sources", and its 11ases to reflect those parameters in which the C&D batteries differ from AT&T batteries. The required changes are as follows:
A proposed change to SR 4.8.2.1.2.a.2 adds a total battery terminal float charge voltage limit of 2177.6 volts for the C&D batteries. This SR ensures the effectiveness of the battery charger to float charge the battery, liloat charge is the condition when the charger is energizing the battery to overcome the internal cell losses and to maintain the battery in a fully charged state. The proposed limit for the C&D battery represents the minimum value of the manufacturer's recommended total battery float charge voltage range of120 to 2.25 volts per cell.
(2.20 to 2.25 volts per cell) x (58 cells) = 127.6 to 130.5 volts.
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Table 4.8 2 is revised so that it applies to the AT&T and C&D batteries. This is done by replacing the reference to the Gould battery at the top of page 3/4 8-12a with "C&D", changing Table Notation (4) to clarify that the electrolyte specific gravity is enccted for tcmpna:ct; ark, and mising tne enarging cunent in Tabie Notation (5) to 3 amps to reflect the C&D batteries larger capacity. This is done because, with the exception of the charging current, all the parameters listed in this table for the Gould batteries are identical to the manufacturer's recc,mmended parameters for the C&D batteries. Table Note (4) is changed becaut.e the manufacturer recommends correcting the specific gravity of the c;ectrolyte for temperature, but not for level. This is consistent with Annex A oflEEE 450-1995. The Bases for this Table are also revised to replace Gouki references for the voltage values with "C&D".
CTS SRs 4.8.2.1.2.c and 4.8.2.1.2.f allow for either a modified perfonnance discharge test (AT&T) or the normal performance discharge test (Gould) to be performed in lieu of the service test. The proposed change would allew the modified and normal performance discharge test to be performed for both the C&D and the AT&T batteries.
The modified performance discharge test reflects the current standard for testing replacement batteries as noted in IEEF Standard 450-1995. This test is a simulated duty cycle test typically consisting e just two rates: 1) the one minute rate published for the t attery or 2) the largest cmrent load of the duty cycle, followed by the test rate employed for the performar.cc ten, both of which envelope the duty cycle of the service test. Since the ampere hou i removed by a rated one-minute discharge represent a very small portion of th battery's capacity, the test rate can be changed to that for the performance test without significantly affecting the results of that performance discharge test. The battery terminal voltage for the modified performance discharge test shouid remain above the minimum battery tenninal voltage specified in the battery service test for the duration of time equal to that of the service test. A modified performance discharge test is a test of the battery's capacity and its ability to provide a high rate, shoi Juration load (usually the highest rate of the dt.ty cycle).
This will confirm the battery's ability to meet the critical period of the load duty cycle, in addition to determining its percentage of rated capacity. Initial conditions for the modified perfonnance discharge test should be identical to those specified for a service test.
SR 4.8.2.1.2.e provides acceptance criteria for battery capacity and degradation. The durations and values are consistent with IEEE 450-1995. Specifically, the 60 month surveillance verifies that the battery capacity is at least 80% of the manufacturers' rating. This section also allows a modified perfonnance test to replace a perfomiance test. The proposed change changes Gould to C&D and permits the use of a modified performance test in lieu of a service test for both AT8 T and C&D by removing the reference to AT&T and removing the performance discharge test reference for Gould.
SR 4.8.2.12.fidentifies accelerated testing requirements for a battery that is near its
- end oflife or shows signs of degradation. The proposed changes are consistent with 3
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4 IEEE 436-1995. Specifically, the proposed change 1) changes the frequency from 18 months to 12 months 2) replaces Gould with C&D in the definition of degradation, and
- 3) adds that a note,rrmitt a two-year test r intem! rs Img = the br.tter/ &livm at i
least 100% of rated capacity and shows no signs of degradation. In addition, a note is added to clarify that as long as a battery delivers at least 100% of the manufacturer's rated capacity and shows no signs of degradation, a two-year interval is acceptable.
The accelerated 12 month testing applies if car acity drops more than 10% or the battery has reached 85% ofits service life. The se changes are made to be consistent with IEEE standard 450-1995.
The reference to draft IEEE 450 in the bases, which describes the modified performance discharge test, is changed to IEEE 4501995 to reflect the current.
document. The details of the test are unchanged however, the reference to the AT&T batteries is deleted as the modified performance test applies to both the AT&T and the C&D batteries.
CTS Actions 3.8.2.1. c (1) and 3.8.2.2. b (1) specify a crosstic loading limit of 63 amps for the Gould batteries and 100 amps for the AT&T batteries. The Gould provision is deleted and a crosstic loading limit of 200 amps is proposed for the C&D batteries to reflect its larger capacity. The 100 amp crosstic is retained for the AT&T batteries.
D.
IMPACT OF Tile CilANGES The proposed changes will not alter the safety functions of the DC system or its equipment.
The proposed change allowing for the replacement of the batteries introduces new limits for the C&D battery because some ofits parameters differ from those of the installed AT&T battery. The limits for the AT&T batteries are retained to allow for the transition period needed to install the C&D batteries. The C&D batteries meet or exceed the design and functional requirements of the installed AT&T batteries. Replacing the AT&T batteries will not impact the function of the DC system. The operational performance of the C&D batteries are expected to be cuperior to those of the AT&T batteries due their higher capacity.
The proposed crosstic loading limit of the 200 amps for the C&D batteries takes credit for the larger capacity of the C&D batteries. The C&D batteries wue sized to have sufficient capacity to energize the design basis DC loads from an operati.ig unit with the IEEE-485 design margin of 5% while maintaining the desired limited DC load cat.ent for the other unit.
The sizing of the C&D batteries is conservative compared to the sizing of the AT&T batteries tvcause the crosstic load limit of 100 amps for the AT&T batteries utilizes a portion of the IEEE-483 design margin. The crosstie loading requirement for the AT&T battery is retained to allow for the transition period needed to install the C&D batteries.
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1 SCHEDULE REQUIREMENTS Commonwealth Edison requests that the review and approval of the proposed amen'dment be -
- completed by 'tugust 5,~1998 to support replacement of the battery during the Unit I refueling, s
- outage scheduled to begin on September 5,1998.
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