ML20115D711
| ML20115D711 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 07/09/1996 |
| From: | Mcmeekin T DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9607150241 | |
| Download: ML20115D711 (55) | |
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0 DukeIbwerCompany T. C hicMirza McGuire Nuclear Genemtion Deparonent VicePresident 12700Hagen FenyRoad(MG0lVP).
(M)8754800 Huntenville, NC280784985 (M)8754809 Fax DUKEPOWER July 9, 1996 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C.
20555 tbject:
McGuire Nuclear Station Docket Nos:
50-369 and 370 AT&T Round Cell Battery - Periodic Update
Dear Sir:
Per our previous commitment on this issue, please find attached the required periodic update.
We are pleased that an industry group has been established to address the AT&T Round Cell Battery issues, j
We look forward to supporting this industry efforts.
I' If you require further information, please contact James E.
Snyder at (704)875-4447.
Very truly yours, f0Mf T. C. McMeekin 9607150241 960709 PDR ADOCK 05000369 P
PDR po
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t e
o, June 20,1996 Mr. James E. Snyder l
Regulatory Compliance Manager McGuire Nuclear Station l
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Subject:
AT&T Round Cell Battery Test Acceptance Criteria Periodic Update per 12/05/95 Letter to NRC, Commitment #3 PIP 0-M95-2131, Corrective Action #5 I
t In letter dated 12/05/95, McGuire committed to become actively involved with the appropriate j
industry groups in resolving the battery test acceptance criteria issue. Due to the industry-wide l
nature of this issue, McGuire commits to work with the appropriate industry groups and provide l
an update to the NRC by June 30,1996. He following is an update status of this commitment:
As an initial effort to establish communication with industry groups, McGuire requested that AT&T - Power Systems help form a Round Cell user's group. This group, consisting of all.
representatives of all five nuclear utilities, Wylic, Laboratories (present third party qualifier),
vendor representatives, and AT&T (now Lucent Technologies) has been successfully formed.
The USNRC has been invited to attend meetings as observers. The group is now well established and officially known as the AT&T Round Cell Nuclear Utility User's Council, chaired by Duke Power. The Council has an approved Charter which identifies purpose, scope, operating agreement, expectations, and milestone dates (Reference Attachment A). Several of the Charter expectations are associated with battery test acceptance issues.
In nuclear safety related a pplications, battery test acceptance criteria is documented in station specific Technical Specificatic.a. Mest battery Technical Specification surveillance requirements am influenced by IEEE Standards. Existing IEEE Standards do not identify individual manufactures, therefore applicability of AT&T Round Cell batteries with their unique characteristics are not fully understood. Duke Power has submitted in writing to the IEEE Standards Board, a request for interpretation of IEEE Std 450 and IEEE Std 485 regarding Round Cell applicability (Reference Attachment B). This interpretation request was addressed at the Spring IEEE SCC-29 battery meeting in Gulf Shores, A1. During the meeting, Lucent Technologies representatives stated that Round Cell should be applicable to both standards and are similar to conventional rectangular cells in most regards. The IEEE committee requested that Lucent Technologies provide technicaljustification to substantiate their statements. Therefore, i
the request for interpretation was deferred until additional information is provided.
i The User's Council is working with Lucent Technologies to provide technical justification and n: commendations requiring IEEE applicability to Round Cells. This will be submitted for consideration and presented at the Fall IEEE SCC-29 battery meeting in Philadelphia, Pa.
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Minutes from the last AT&T Round Cell Nuclear Utility User's Council meeting held May 22-23, 19% in Charlotte, NC are provided along with the latest Charter revision and agenda for the next meeting to be held July 30-31 in Chicago,11 (Reference At::chment A).
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Danny L. Hepler MNS Electrical Systems & Equipment Engineering cc w/ attachments:
D.M. Jamil W.N. Matthews K.L. Crane File MC-1356.01
.AKAcRMeNT A June 17,1996 l
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l AT&T Round Cell Nuclear Utility User's Council l
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Subject:
Meeting Minutes and Agenda Topics for the next Meeting The minutes of the May 22-23,1996 meeting in North Carolina are enclosed along with the l
Agenda Topics for the upcoming meeting July 30-31. Please note the various action items and i
l address them in a timely manner in order for us to remain on schedule.
)
Thank you for the excellent suppon and teamwork you have demonstrated. If you have any l
questions,I may be reached at (704)875-5899 and fax number is (704)875-4013. My mailing address is:
Duke Power Company l
McGuire Nuclear Station (MG05EE) 12700 Hagers Ferry Road Huntersville, NC 28708 i
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l-btJA/
W. N.(Bill) Matthews Chairperson i
O MINUTES l
AT&T Round Cell Nuclear Utility User's Council MAY 22-23, 1996 Duke Power Charlotte, NC 1.
The meeting was called to order by Mr. Matthews.
I 2.
Self introductions of members and guest were completed.
l Reference Attachment 1 for the attendance list.
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3.
The first order of business was to review and adopt the charter for the Council and the charter was adopted 4
unanimously.
Reference Attachment 2.
4.
The Council was informed by Mr. Kelly of an upcoming i
meeting involving Lucent Technologies, JHK Associates and Wyle Laboratories.
It was the consensus of the Council to draft a list of questions for Lucent Technologies to address in a timely manner due to the lack of support in the past and the numerous open items remaining from the previous meeting in Gulf Shores.
It was determined that Mr. Weeks would take the list of questions back to Lucent Technologies and a copy of the list would be presented to the Lucent Technologies representative attending the upcoming meeting with Mr.
Kelly. Mr. Kelly (Action Item) will also inquire of the appropriate management designee to address the formal letter to, if needed, and advise the Chairperson.
I Mr. Weeks volunteered to document the questions as they surfaced during the meeting.
The list of questions was finalized (reference Attachment 3) and the Council agreed to allow Lucent technologies a two week period to respond prior to the Council drafting a formal letter to the appropriate level of management in Lucent technologies.
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5.
A verbal synopsis of past problems and lessons learned was presented by Mr. Ash Agrawal (Expectation #4).
Additional information was requested from each member by Mr. Agrawal and it was agreed upon that all members (Action Item) were to submit a written report of their operating experience to Mr. Agrawal by 6/10/96. Mr.
Agrawal (Action Item) would then compile and submit a report by 6/17/96 to the Chairperson for distribution to the Council.
Tnis operating experience report would serve as the initial roll out and as our experience base increases with the use of these batteries, information shall be forwarded to Mr. Agrawal for incorporation into this operating experience data base.
6.
Mr. Hypse presented a preliminary paper, co-authored by Ms Barleycorn, on the results of testing to determine the optimum method of charging the AT&T High Specific Gravity Round Cells (reference Expectation # 1 and ).
All members (Action Item) were to review the paper in detail and provide comments to Mr.
Hypse within the following week.
Mr. Hypse would then consolidate these comments and include them in the final paper scheduled for 9/96.
7.
Discussion followed concerning sending several of the Unit 2 Palo Verde cells removed from service to the Argonne Testing Facility along with several of the Braidwood cells.
Mr. Koenig (Action Item)has the lead on coordinating this additional testing.
8.
Mr. Weeks advised the Council that additional testing by Lucent Technologies was planned at Conshohocken, Pa.
for the low specific gravity cells.
The test plan has been drafted and the purchase order has been written for the test cells. He was not able to go into greater details at this time, but information will be shared on a fixed schedule.
9.
Mr. Weeks presented a copy of a letter (reference Expectation # 3 and Attachment 5) from Lucent Technologies to Mr. Kurt Uhlir, of Comed, that stated "IEEE-450 Section 5.2.c applied to the Round Cells.
It is Lucent Technologies position that a 5% limit for the Round Cell or any other cell design is an unreasonable 2
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requirement.
The Round Cell does not fail from positive grid corrosion or seal leaks, but is otherwise substantially like other lead-acid designs and should therefore be subjected to the same performance criteria applicable to all lead-acid designs addressed in IEEE-450." In addition, test data from the High Gravity Round Cell test in Conshohocken, Pa. was distributed to the Council (Reference Attachment 6).
Discussion pursued regarding the accessibility of the supporting documents for the positions taken regarding applicability of IEEE-450.
Some members felt that additional data was needed prior to the Council's submittal of a " Request for Interpretation" to the IEEE-450 Working Group.
10.
The agenda item to Identify and Determine Applicability of IEEE Standards (Expectation # 3) was led by Mr.
Koenig.
Significant amounts of work remains to be done on this expectation.
Mr. Koenig has requested all members (Action Item)to review the IEEE Standards and remark them as necessary along with the justification, and forward them to him by June 7.
Mr. Koenig (Action Item)will compile these comments and distribute them to the Council Members by June 14.
A follow-up conference call will be held on June 20 to review any additional comments or to resolve any discrepancies.
11.
Mr. Weeks stated that' originally, platinum (3.0 mg) was added to Round Cells in the 1980 time-frame in order to improve float characteristics. In 1990, the platinum content was reduced to 0.12 mg and in 1994 increased to 0.24 mg due to crystallization of the positive plate.
Mr. Hypse noted that the content of platinum was not j
the sole contributor to the loss of capacity phenomena, since the HG 1 string that exhibited a loss of capacity contained both the 0.12 mg and the 0.24 mg levels of platinum. Mr. Weeks then shared coding on the top of the post for the platinum levels.
One **" indicates 0.12 mg of platinum and two **" indicates 0.24 mg of platinum.
Mr. Weeks also informed the Council that the plates for the low and high specific gravity cells are the same components.
(Lessons Learned) 12.
The issue of interchangeability was discussed and it was the consensus of the Council that Round Cells are 3
o 1
interchangeable with a cell in an existing string as l
long as the specific gravity and ratings are the same.
If the existing string has loss of capacity, then the introduction of a cell from a different string may l
accentuate the existing problem in the remaining string. This characteristic is also true of the l
traditional square cells.
This was based on vendor guidance as well as actual in service data. (Lessons Learned) 13.
Mr. Koenis shared an experience with the electrolyte level with the Council.
Based on guidance from the vendor, the electrolyte level can be above the normal level if the cause for the increase is understood.
Mr.
i Koenig (Action Item) will send a copy of this letter to the Chairperson for distribution to the Council.
(reference Attachment 8)
(Lesson Learned) 14.
A discussion evolved on whether the vendor's or IEEE's temperature derating (K) factor should be used with the l
Round Cells. This issue was tabled and should be addressed with the discussion on Expectation #3.
The Chairperson (Action Item) will include this on the agenda for the next meeting.
15.
The need to examine the impact of shallow repetitive discharges was discussed and determined that this would be folded into the scope of Expectation #1.
Ms Barleycorn and Mr. Hypse (Action Item) will address this concern as part of their position paper.
16.
It was also discussed and agreed upon to use empirical data to substantiate the positions in the paper for Expectat'on #1.
Ms Barleycorn and Mr. Hypse (Action Item) will incorporate this into the next revision.
17.
Concerns were raised that the industry and NRC may not fully understand the design differences of the Round j
Cells and how their Life Cycle Curve differs from the l
traditional square cells.
In preparation for the upcoming submittal for an IEEE Request for t
Interpretation, Mr. Koenig (Action Item) agreed to develop a paper addressing the following issues:
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Basis for Traditional Knee Curve i
i Positive Plate Growth Phenomenon Guidelines and Basis for Cell Degradation I
Use NiCads as an Example of Dif ferent Life Cycle Curves i
18.
The next meeting of the Council will tentatively take place on July 11-12, 1996 in Chicago, Ill.
Mr. Koenig (Action Item) agreed to make the necessary meeting arrangements.
l 19.
The meeting was adjourned.
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l CHARTER.
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DATE:
June 18,1996 l
TITLE:
AT&T Round Cell Nuclear Utility User's Council REVISION: 1 l
CHAIR:
Duke Power MEMBERS: LucentTechnologies l
Arizona Public Service Comed (Commonwealth Edison)
Duke Power Company l
GPU Nuclear Wyle Laboratories Wolf Creek Nuclear Operating Corporation l
l PURPOSE AND SCOPE:
1 The purpose of the User's Council is to bring together knowledge and experience of AT&T Lineage 2000 Round Cell Batteries in order to address immediate industry and regulatory j
concerns of performance and behavioral characteristics that have evolved from recent testing and operating experience. Long term, the team will collectively work to resolve questions and issues that are unique to Nuclear Utility applications and address applicability of IEEE standards.
l OPERATING AGREEMENT:
The Council shall conduct business using Robert's Rules of Order. Group positions and rulings shall be established by consensus of majority members present at meetings. Urgent issues will be resolved between meetings utilizing written correspondence and balloting of active members.
EXPECTATIONS:
- 1. Evaluate charging methods for high specific gmvity Round Cells l
Available battery capacity following Performance Test recharge l
Available battery capacity following an unplanned discharge on-line l
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- 2. Identify and resolve concems that apply to Standard Technical Specifications
- 3. Identify and determine applicability ofIEEE Standards
- 4. Review historical problems and lessons leamed
- 5. Develop position on testing and correlation of intemal cell impedance / resistance to cell perfccmance
- 6. Investigate performance and behavioral characteristics of high and low specific Round Cells
- 7. Establish communication between member and methods of data pooling
- 8. Investigate root cause(s) of Palo Verde and Braidwood battery capacity loss l
MILESTONES GOALS:
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+ Next Meeting in Charlotte, NC (met)
-5/22 & 23/96
+ Issue report documenting results of recharge testing
- Approx.9/96 l
+ Issue root cause reports for Palo Verde and Braidwood battery
- Approx.9/96 loss of capacity i
+ lssue report addressing cell impedance / resistance testing Vs cell
- Approx.10/96 l
performance
+ Establish group position on applicability of IEEE Standards
- Fall 96 IEEE Mtg and present to IEEE Standards Board i
+ Document position and basis of Standard Technical Specification
- AfterIEEE Mtg issues l
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l lo Charter Attachment l
Page 1 of 8 i
EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE
- 1. Evaluate charging methods for high specific gravity Round Cells Available battery capacity following Performance Test recharge e
Discussion: Discharge testing has indicated that 100% capacity is not available immediately following recharging after a battery Performance Test. In order to fully understand this phenomenon, additional testing may need to be performed to determine the characteristics of constant current and constant potential charging.
Action: Evaluate and compare both constant current and constant potential charging.
Available battery capacity following an unplanned discharge on-line Discussion: After an unplanned discharge on-line, plants will use their permanent plant constant potential chargers at float potential to charge the batteries. An issue has been raised conceming the charge retum rate using this method of chargiag and the available safety margin.
Action: Evaluate effectiveness of constant potential charging at float voltage following an on-line discharge. Determine rate of charge retum and evaluate safety margin over accident duty cycle. This effect should also address shallow repetitive discharges.
Sponsor: APS Completion Date:
Preliminary - Approx. 6/96 (met)
Final
- Approx. 9/96 l
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Charter Attachment Page 2 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE l
- 2. Identify and provide reconunendations to resolve concerns that apply to Technical Specifications Discussion: With the unique characteristics of AT&T Round Cells, generic parameters and Surveillance Requirements need to be evaluated for applicability.
Action: Review Standardized Technical Specification for applicability. Document i
positions and basis.
Sponsor: APS Completion Date: (90 days following resolution of IEEE 450 issue) l
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Charter Attachment Page 3 of 8
. EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE
- 3. Identify and determine applicability ofIEEE Standards IEEE Std. 450 Discussion: Due to the unique design and characteristics, it has not been established or documented if AT&T Round Cells are covered by this standard.-
l Action: Determine if Round Cells are included in IEEE Std. 450. If so, to what extent and should differences be addressed. If Round Cells are not included, how and where should they be addmssed. Request a Standards interpretation based on date submitted from User's Council.
l IEEE Std 485 l
Discussion: IEEE Std. 485 is normally used for sizing (including various margins) lead-acid batteries used at Nuclear Stations. The standard methodology uses battery l
performance discharge rates and curves published by battery manufactures. AT&T does i
not have data published in terms needed for battery sizing used by this Standard.
l Performance data has been collected but not officially published by Lucent Technologies.
Action: Request a Standards interpretation based on data submitted from User's Council.
l Sponsor: APS l
Completion Date: (Request submitted prior to fall 96 IEEE Working Group meeting) i
)
Charter Attachment Page 4 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE x
- 4. Review historical problems and lessons learned Discussion: Significant problems and lessons leamed during service need to be shamd with the group from both a historical perspective and on-going basis.
Action: Research problem history and record on-going problems and lessons learned.
Solicit input and share with the group.
Sponsor: GPUN Completion Date: Initial Rollout Approx. 6/96 (met)
A
Charter Attachment Page 5 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE l
- 5. Develop position on testing and correlation ofinternal cell impedance / resistance to cell performance Discussion: Comed, Braidwood Nuclear Station has been taking intemal cell impedance measurements on designated strings of Round Cells and comparing values with battery Performance Test results. The emphasis is to establish a correlation between cell impedance and capacity. This testing also explores the effect of entrapped gases generated during charging on cell impedance.
Action: Document test results and determine validity of correlation and benefits of impedance testing.
Sponsor: Comed Completion Date: Approx.10/96 e
Charter Attachment Page 6 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE
- 6. Investigate performance and behavioral characteristics of high and low specific gravity Round Cells Discussion: Recent pmblems and abnormalities of Round Cells have been limited to those with high specific gravity electrolyte. The effects of high specific gravity electmlyte on performance and behavioral characteristics are not fully understood.
Action: Investigate performance and behavioral characteristics of high and low specific gravity cells. Determine and document differences of each.
Sponsor: WolfCreek Completion Date: Approx. 4/97 i
Charter Attachment Page 7 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE
- 7. Establish communication between members and methods of data pooling Discussion: With national participation, the User's Council member locations are such that frequent meetings are impractical. In order to share ideas and data, a more direct method of communication is needed.
Action: Develop a network between Council members using the Intemet, that will provide convenient distribution of conespondence, information, and test data. Method should be fast, simple and convenient such that frequent correspondence and sharing of data is encouraged.
Sponsor: Duke Power CompletionDate: Approx.6/96 (met) l l
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Charter Attachment Page 8 of 8 EXPECTATIONS DISCUSSION / ACTION / SPONSOR / COMPLETION DATE
- 8. Investigate root cause(s) of Palo Verde and Braidwood battery capacity loss Discussion: Recent Perfornunce Tests of Round Cell batteries at Palo Verde Unit 2 and Braidwood Unit I have indicated unexpected and premature loss of capacity. Root cause evaluations at each station are ongoing. The results of these evaluations should be reviewed and shared such that lessons are learned and applied to develop a better understanding of Round Cell behavior.
Action: Investigate root cause(s) of capacity loss and evaluate results.
Sponsor: APS/ Comed Completion Date: Approx. 9/96 l
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AT&T Round Cell Nuclear Utility User's Council 1.
On 11/30/95 " Pam Larkin accepted an action item to issue the AT&T List ISH Expected Performance Discharge Curves via a Power Flash." The utilities need 1 min ~. to 8 hr. expected average performance data.
l 2.
Need a utility oriented product manual.
3.
Updated product manual with correct high gravity data.
i 4.
A final report on the Chonshohocken testing was promised at the 11/30/95 meeting.
5.
Clarification of the Part 21 responsibility for the Round Cells at-McGuire.-
6.
Official position on high gravity cells.
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Official position on sales to utilities.
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What future support can the utilities expect?
9.
Who is the management person at Lucent Technologies that is responsible, and will be responsive, to utility needs?
- 10. Who is the point of contact for business (i.e. warranty) and technical questions?
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1 PRELIMINARY CHARGING METHODS FOR THE AT&T LINEAGE 2000 j
IIIGH SPECIFIC GRAVITY ROUND CELL l
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Mark L. Hypse / Judith K. Barleycorn i
l Arizona Public Service Co.
1 Palo Verde Nuclear Generating Station Phoenix, Arizona Abstract The purpose of this paper is to present the results of testing to determine the optimum method ofcharging AT&T Lineage 2000 High Specific Gravity Round Cell and provide recommendations to the Nuclear Utility Round Cell Users Council.
Introduction Since 1991, AT&T high specific gravity Round Cells have been in use at Nuclear Power Plants. The first nuclear plant to install Round Cells was the Duke Power - McGuire plant. Over the next three years additional high specific gravity Round Cells were installed at the Arizona Public Service - Palo Verde Nuclear Generating Station (PVNGS) Units 1,2, & 3 and the Comed - Braidwood Station Units 1 & 2. Overall performance of the Round Cells has been good. Problems characteristically identified with the rectangular cell design such as post corrosion / seal leakage and grid corrosion have not been the case with the Round Cell. However, as is the case with most new technological applications, there has been problems. Some of these problems are believed to be as a result of the lack of test history for the high specific gravity Round Cell. AT&T has had a long history of testing with low specific gravity cells. The low specific gravity Round Cell has been in existence since 1972, with over 750,000 installed world wide. The high specific gravity Round Cells, however, have not seen wide spread use and very little of the original developmental test data was from high specific gravity Round Cells. In addition, most of the product manual instructions are based on the testing history from low specific gravity cells.
In 1994, PVNGS Unit 2 conducted performance tests in accordance with IEEE-450 on all four banks of batteries (240 cells). These tests indicated an unexpected loss of capacity of approximately 10% from the initial installation of the Round Cell batteries. An extensive root cause investigation ensued. The root cause l
investigation determined that the loss of capacity was due to loss of positive plate material from improper curing during fabrication.
As a result of poor test results, PVNGS procured replacement cells from AT&T. In order to verify that the root cause investigation identified manufacturing problem had been corrected, PVNGS performed successive i
1
discharges on the replacement cells. It was noted during this testing that the method of c of successive discharges during a short time interval greatly effected the resultant pe I
l In 1995, Braidwood Station completed performance tests on both of their battery banks. O capacity loss. The other battery, however, did show an unexpected capacity loss. The bat had had an inadvertent discharge on-line approximately two weeks prior to the performanc the time, it was suspected that the battery had not been completely recharged and a commitmenj perform single cell capacity tests after the battery floated for a number of months. A single cell test was performed in January 1996 and again there was additional capacity loss.
The events at Braidwood and PVNGS, demonstrate a need to better understand the charging charac the Round Cell. It was clear from plant performance testing that the high specific gravity Round Cell user not have sufficient information to optimize their charging procedure following a discharge. In addition,it also evident that the expected performance results for a Round Cell was not completed known af This paper will review the testing that has been conducted to determine the optimum charge met characteristics for various charging methods.
Round Cell Testine Constantpotentialcharging atfloatpotential In 1995, APS & AT&Tjointly performed testing to determine the acceptability of charging Round Cells usin float potential (2.25 vpc) following a full capacity discharge. Twenty four new cells manufactured at the Leola, Pennsylvania factory were shipped to the C&D test facility in Conshohocken, Pennsylvania for performance testing. The C&D test facility was chosen for testing due to the close proximity to Leola and the laboratory quality testing standard at the facility.
The twenty-four cells would be divided into six groups of four. Five of the groups would be used for float charge testing and one group would be held as a controlled group. The test plan was to conduct a performance test at the two hour rate (514 amps) on each group as a baseline test and then allow each group to charge at 2.25 vpc. The first group would float for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and then a second performance test at the two hour rate wouM be conducted. The second performance test would be used to detennine restored charge. The subsequent groups would be float charged for increasingly longer times. Entering into the test plan it was expected that as time on float increased, restored charge would also increase. But as is shown in Figure 1, charge return decreased with time on float to a point where it leveled off at approximately 88% out to 32 days. Additional testing on the groups after their second discharge for various float times did not provide useful data due to the degrading factor of cycling the Round Cells repetitively over a short interval. The only additional data points which could be added to show restored charge after an extended period of time were from the spare cells at i
PVNGS. This data is depic:ed on Figure I at 180 and 360 days.
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Constant Potential Charging 5
Figure 1 5
e 120 a:
110 ca 100
.c
'~
1 2
3 7
32 180 360 Days on Charge At each one of the three PVNGS units there are four spare cells which are installed in the Channel "A rack. These cells are tested along with the 60 cells which make up the plant battery to ensure that the op:rable and ready for use in the event of a cell failure on-line. The four cells, however, are charged at float potential independently of the 60 cell betk aRer their discharge testing. Using this test data it was known that float potential does return full charge, but only after a time period somewhere aner 32 days and prior to 18 days.
Constantpotential charging at an increasedpotential and a boost charge ARer the unexpected results at float potential it was decided that it would be of benefit to determine the ch return using the method of charging that was in use at PVNGS. It was expected that by increasing the charge potential better results could be obtained. This testing would be done on 3 of 12 new cells that were shipped from Leola to the C&D test frdlity for additional testing. The plan for this group of cells was to duplicate the PVNGS charge method after a.ull perfonnance test discharge.
The PVNGS method of recharging uses the plant charger set at 2.33 vpc for initial charging. Charging using th plant chargers is continued until charge current is less than 10 amps. The second step of the charging procedure removes the battery from the DC bus and a portable charger is set at 2.5 vpc for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. In addition, 3
specific gravity must be above 1.290 to consider the charge complete. As per IEEE 450, a float charge of 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> follows the charging to allow for specific gravity and electrolyte levels to stabilize When this method was used on the cells at the C&D test facility, results indicated a 94% restoration of after 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> on float. When compared to float potential charging for approximately the same time period, float potential restored 88% of charge ( See Figure 2).
Charging Comparison Figure 2 c
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100 95 90 l
SS r
80 U
75 70 2.25 e 2.33/2.5 vpc Charging Potential i
i Constant Current Charging
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The C&D factory has always used constant current charging on Round Cells after discharge testing. This method i
of charging has been used to ensure a controlled quantity of amp hours are returned to the battery after a I
discharge. He AT&T charging specification requires 130% - 140% of the discharged amp hours retumed.
j When PVNGS was performing acceptance tests on replacement cells for Unit 2 it was observed that constant current charging consistently provided an increased percentage of charge return over a shorter period of time. In addition, it was also observed that constant current charge seemed to alleviate to some degree the degrading I
effect of cycling over a short interval.
At the C&D test facility constant current charging was tested on a group of four cell from the initial twenty-four cells. As expected constant current charging restored more charge sooner than constant potential charging at j
float voltage. The four cells were cycled five times (See Figure 4). As expected after the third cycle capacity sufTered due to over cycling.
4
Constant Current Charging Figure 4 x
I 120 o
11/95 12/95 12/95 1/96 1/96 Dates of Performance Tests All the above tests included a minimum 7 day float period after constant current charging. However recent testing at PVNGS has shown that full capacity can be returned in as little as 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> using constant current charging. This is expected due to the higher potentials achieved with constant current charging. At these potentials charge restoration rate is expected to be at least as good as the constant potential method at increased potentials. Constant current charge potentials can reach as high as 2.8 vpc.
Conclusions Battery Capacity Safety Margin The batteries at Braidwood, PVNGS, and McGuire are sized such that they have considerable safety margin (See figure 5). All three plants used IEEE-485 as the basis for their battery sizing, however not all ofIEEE-485 was followed. The battery temperature correction factor used was from the AT&T Product Manual as opposed to the table from the IEEE standard. This is understandable since the IEEE table was based on vendor information j
from rectangular cell manufacturers. Also, the required cell capacities were calculated without design margin and aging margin. These factors only add margin for initial cell selection and serve no purpose when evaluating actual battery capacity margin.
4
!g Capacity Safety Margin Figtre 5
~
/
^A
/'
A
/~
'A u 1CO Braidwood McGuire PVNGS Nuclear Part E Required Capacity C Rated Ca pacity Capacity after an inadvertent discharge After an inadvertent discharge currently all three plants would restore charge to the Round Cells using their plant chargers at float potential. An operability evaluation would be made after this discharge to ensure that sufficient capacity remains in the battery for a design basis accident duty cycle. Since at all plants there is marg between the rated capacity of the battery and required battery capacity, some discharge on line would be l
acccptable.
A conservative estimate of projected capacity versus time on float can be derived using the testing data obtained from the previously discussed testing at the C&D test facility. The testing at C&D returned a percentage of charge after a given number of hours on float. This test data is from a full discharge of the battery, so using these percentages are expected to be conservative. For this paper the PVNGS discharge data is used as an l
example since in actual application PVNGS could experience the maximum discharge amp hours and still remain operable. An estimate of restored charge can be obtained using the charge restoration percentages over time from Figure 1. These values can then be multiplied by the maximum amp hours that would be discharged and still consider the battery capable of performing its design basis function.
It should be noted that the likelihood of taking out this many amp hours during a two hour action statement even considering the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> shutdown time is extremely remote. Especially considering the alarms which would be present in the control room, the fact that all plants have swing chargers and typical normal plant loads are approximately 100 amps. Hence, it is expected that the total amp hours removed during normal operations would never approach the maximum allowed.
Figure 6 shows the expected capacity return over time for PVNGS after the maximum permissible discharge.
As can be seen from the graph, 97% of battery charge will be restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. As discussed 6
b previously, as the battery floats available charge may decrease to a coint whe e it levels iff at approximately l
88%. Taking this into consideration this equates to a minimum available charge of approximately 94% at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
i CHARGE RECOVERY AT PVNGS Figure 6
/%
a 34 7
P f
a 53 C
i t
y 24 I2 Hours Charging after aperformance test From the test data (Figure 4)it is clear that constant current charging restores the greatest percentage charge in the shortest period of time to the Round Cell. When conducted in accordance with the factory method, with 130-140% of discharged amp hours returned, a 100% charge can be expected in as little as seven days. Minimal test data exist for less than seven days but recent testing at PVNGS on Unit 2 cells does show an apparent restoration of approximately 100% of charge in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Constant potential charging when conducted at float potential also restores a minimum 88% charge (Figure 1) in less than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. From testing of the spare cells at PVNGS, we know that 100% charge is returned between one and six months. When the charge potential is increased, constant potential charging can be expected to restore 94% charge in as little as 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
When looking at all the data it is evident that the potential of the charge is critical to the rate of charge return.
Constant current charging at potentials as high as 2.8 vpc restores the greatest charge in the shortest time period.
Whereas float potential charge (2.25 vpc) takes a considerable period of time to restore 100% charge. Charge potentials of 2.33-2.5 vpc can improve the rate of charge restoration over float potential.
7
Chargine Recommendations
- 1. Round Cell users should review current plant operating and emergency procedures for a loss o DC chargers to ensure battery discharge data will be recorded and Engineering is involved determination.
- 2. Round Cell users should determine in advance the maximum discharge in amp hours that can occur at rates and leave sufficient capacity for the accident duty cycle.
- 3. Float potential charge aftsr an inadvertent beharge is acceptable, however Round Cell us placing the charger at equalize potential to increase the charge rate of return. Increased potential has been shown to increase the rate of charge restoration.
2-
- 4. Constant current charge or constant potential charge will restore full charge, however, Round Cell users that choose to use constant potential charge should include potentials of 2.33 vpc and above in their recharge procedure.
- 5. Constant current charge should be conducted such that 130 - 140% ofdischarge amp hours are returned.
References
- 1. ANSI / IEEE Std 450-1987. IEEE Standard for Maintenance, Testing, and Replacement of Large Lead Storage Batteries of Generating Stations and Substations.
- 2. ANSI / IEEE Std 485-1983. Standard for Sizing Large Lead Storage Batteries for Generating Stations and Substations.
- 3. AT&T Lineage 2000 Round Cell Battery-Product Manual. Issue 1 August 1990
- 4. IEEE Conference Paper - Biagetti"The AT&T Round Cell Revisited: Lessons Learned; Significant Design Changes; Actual Field Performance Vs. Expectations" 8
Addendum Additional proposed testing to confirm the following conclusions:
- 1. By increasing the charge potential to equalize potential (2.33 vpc) aner an unplanned discharge, the rate of charge return can be improved
- 2. Increased potential aRer a performance test will improve the rate of restoration of charge.
- 3. Constant current charging provides optimum rate of restoration of charge.
Test Plan
- 1. Charge return after an unplanned discharge I
a) Use 9 remaining cells at C&D X/X/96 b) Discharge worst case AHr's X/X/96 3
c) Place on equalize charge (2.33 vpc)
X/X/96
- 1. Charge until current stabilizes l
- 2. Record specific gravities l
l
- 3. Record charging current continuously j
d) Performance test three at a time X/X/96 i
r 4
4
- 2. Charge return using 2.5 vpc 1
t a) Use 12 HG-13 cells X/X/96 b) Performance test to establish baseline X/x/96 l
c) Recharge and place on float X/X/96 d) Performance test four at time (24,72,168)
X/X/96 j
I 1
i 9
1
- 3. Charge return using constant current method a) Use 12 HG-13 cells.
X/X/96 b) Performance test to establish baseline X/X/96 c) Recharge using constant current method (135% AHr's)
X/X/96 d) Performance test four at a time (24, 72,168)
XIX/96 I
i i
i 10 m-v
l l
/ m i
Bell Labs Lucent Technologies l
Innova 0ons for Lucent rechnologies Bell Laboratones 600 Mountain Avenue Murray Hill. NJ 07974 0636 May 20,19%
Mr. Kurt W. Uhlir Commonwealth Edison Company Nuclear Engineering and Technology Senices 1400 Opus Place, Suite 400 Downers Grove,IL 60515
Dear Kurt,
During the recent IEEE meeting at Gulf Shores, AL, there was much discussion around IEEE 450 Section 5.2.c and its applicability to the Round Cell. During the meeting Lucent Technologies agreed to draA its response to this issue.
BACKGROUND:
IEEE 450-1995 Section 5.2 addresses performance testing of flooded lead-acid cells. In this section it states that a performance test should be performed within the first 2 years of senice, and that this test should be similar in duration to the battery duty cycle. Additional performance tests are to be performed at 5 year intervals until signs of battery degradation appear. The test is to be performed annually thereafter until the battery needs to be replaced. Degradation is indicated when the battery capacity drops j
by more than 10% from the previous performance test, or performance is below 90% of manufacturer's rating.
Battery replacement criteria per Section 7 of the same document states that the battery should be replaced i
if the capacity drops below 80% of the manufacturer's rating if the battery was sized using a 1.25 aging factor. If a lessor aging factor was used, replacement should occur before 80% capacity. Whenever replacement is required, the recommended maximum time for replacement is 1 year. Other factors such as an unsatisfactory service test (based on actual duty cycle) may also require replacement if the condition cannot be corrected.
ISSUE:
Should the Round Cell be subjected to different test and replacement criteria because documentation states that the Round Cell capacity increases with age, and therefore, even a small capacity loss may be viewed as degradation? One position is that only a 5% loss of capacity for the Round Cell should be considered as degradation.
l
RESPONSE
The Round Cell is a pasted plate lead-acid cell with features designed to significantly increase float life, reduce maintenance and increase safety in standard telewommunication applications of long term float and infrequent discharges. The electrochemistry and failure mechanisms are the same for the Round Cell as other pasted plate lead-acid designs except that the Round Cell design has virtually eliminated positive
l a
i l
plate grid corrosion and resulting loss of capacity caused by poor paste pellet-to-grid contact as a cause of failure. However, excessive cycling, premature capacity loss, manufacturing defects, impurity contamination, negative plate / expander problems, shipping damage, connector resistance, improper maintenance, rectifier failure, etc. may also adversely affect cell performance.
i The Round Cell product literature shows increasing capacity with age and lifetimes far greater than rectangular cells in accelerated life testing. The expected increase in capacity is due to the Round Cell's unique positive grid design. As the pure lead positive grid slowly corrodes (" grows"), the corrosion and pellet to-grid contact is uniformly controlled by design throughout its lifetime. The predicted slope of capacity versus age is 0.3% per year over a 70 year period. In 1988,15 year old Round Cells were capacity tested on site at Xenia, Ohio. The capacity was approximately 5% greater than when first installed, and the actual positive grid growth was less than predicted. Figure 1 graphically presents this information. This data showed, at least to the 15 year point, that the theory behind the Round Cell positive plate design and the predicted values were as stated and that positive plate grid corrosion had been essentially eliminated as a failure mechanism.
He Round Cell can still fail for other reasons including but not limited to those mentioned earlier. As an example, Figure 2 shows laboratory cycle life data for 6 different positive plate paste formulations, ne test cells were subjected to a non standard cycling regimen which included 4 shallow discharges for each 1
deep discharge with excessive overcharge between discharges. The example demonstrates that significant performance variation in both the number of cycles and the rate of capacity loss can occur for causes independent of the long term effects of float service.
He IEEE performance test is an effective means ofidentifying capacity loss regardless of the cause of that loss. The currently established 10% allowable window is based on the observed shape of the curve of capacity loss for rectangular cells due to grid corrosion as well as other factors. The propos~ed 5% window for the Round Cell simply because it is advertised to increase in capacity 0.3% per year is unreasonable.
Rectangular cell product literature show capacity increases greater than those reported for the Round Cell for a significant portion of their advertised life, but the 10% window is not in question for those designs.
Five percent is less than the limits of experimental error and reproducibility from cycle to cycle. In addition, any capacity gain due to Round Cell grid growth is barely measurable within the first 10 years of I
float life.
It is Lucent Technologics' position that a 5% limit for the Round Cell or any other cell design is an unreasonable requirement. The Round Cell does not fail from positive grid corrosion or seal leaks, but is otherwise substantially like other lead-acid designs and should therefore be subjected to the same performance criteria applicable to all lead-acid designs addressed in IEEE-450.
Sincerely, 22 S l
Michael Weeks copy with atts. to:
K. Bullock F. Laman K. Murugesamoorthi i
i mee4506
Round Cell Capacity Trend with Age Expected Capacity lacrease (%)
20.0 Capacity vs. fime Ampere Hours.
15.0 IBM Bectangular Ceu pound Celt 10.0 1500 -
1400 IEEE Recommended I
tLevel
-~
/
5.0 1200
/
7 j100 l
1000 l
0 10 20 30 40-60 70 0
5 10 15 20 25 30 Years at float at 77 F f
i i
Years in Service i
I Proven Performance:
Round Cell Po5itive Plate Growth with Age Capacity VS. Time 1
Expected Growth (%)
2.0 Based on AT&TBellLaboratories' accelerated life testing, Round Cell capacity actually increases 0.3 percent peryear over a 70 year 1.5 period. That's more capacity than you'll ever 1
require from your batteries-but added
/
7 assurance thatyou'll be packing the power to
/
handle most emergencies.
0.5 W
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to 15 20 25 30 Figure I Years in Service i
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HIGH GRAVITY ROUND CELLTEST STATUS CONSHOHOCKEN, PA May 20,1996 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1>D2
% of 2 Hrs D2 > D3
% of 2 Hrs D3 > D4
% of 2 Hrs D4>D5
% of 2 Hrs DATE A
2.25V/ces 116.5 Float 104.2 Float 58 days 99.2 Float 14 days 79.7 2.33V to <10A 68.6 02-15-96 780 hrs 70A/4 Hrs 2.8V/4 Hrs 2.8V/4 Hrs Float 11 days Float 8 days Float 7 days B
2.25V/cea 117.7 Float 103.6 Float 14 days 92.0 2.55V/74 Hrs 81.4 Float 11-08-95 69 Hrs 2.60V/73 Hrs Float 6 days C
2.25V/cet 117.9 Float 108.4 Float 41 days 93.6 Float 91.8 2.33V 83.4 05-20-96 45 Hrs 2.5V/8 Hrs 177 days 74 hours8.564815e-4 days <br />0.0206 hours <br />1.223545e-4 weeks <br />2.8157e-5 months <br /> Float 6 days D
2.25V/ce8 119.9 Float 106.5 Float 60 days 92.5 Float 43 days 78.5 2.33V to <10A 63.5 02-15-96 168 Hrs 2.8V/4 Hrs 2.5V/8 Hrs Float 8 days Float 7 days E
2.25V/cen 112.5 70A/20 Hrs 110.5 70A/20 Hrs 100.6 70A/20 Hrs 100.3 70A/20 Hrs 88.4 01-16-96 SA/72 Hrs SA/72 Hrs Float 17 days SA/72 Hrs Float 8 days Float 10 days Float 7 days F
2.25V/ces 117.9 Float 110.9 Float 5 days 107.5 2.6V/73 Hrs 85.6 Float 11-08-95 24 Hrs Float 6 days PVA 2.25V/ces 121.5 2.33V<10A 114.2 2.33V<10A 110.8 2.33V<10A 114.5 2.33V<10A 110.8 See Below 2.5V,8 Hrs 2.7V (120%)
2.7V (120%)
2.8V (120%)
Float 3 days Float 9 days Float 24 days Float 6.5 days GROUP RECHG DCHG 6 RECHG DCHG 7 RECHG DCHG 8 RECHG DCHG9 RECHG DCHG 10 LAST DCHG DS > D6
% of 2 Hrs D6> D7
% of 2 Hrs D7 > D8
% of 2 Hrs D8 > D9
% of 2 Hrs D9> D10
% of 2 Hrs DATE PVA 2.33V<10A 105.1 2.33V<10A 05-10-96 2.8V (120%)
2.5V (120%)
Float 6.5 days Float **
- NOTE: Group PVA accidently charged at 300A for -10 minutes on 5/17/96 during float between discharge #6 and #7. Cels to be floated >6 days prior to discharge #7.
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HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN. PA May 20,1996 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs D2 > D3
% of 2 Hrs D3 > D4
% of 2 His D4 > D5
% of 2 Hrs DATE PVA 2.25V/ceu 121.5 2.33V<10A 114.2 2.33V<10A 110.8 2.33V<10A 114.5 2.33V<10A 110.8 See Bdow 2.5V,8 Hrs 2.7V (120%)
2.7V (120%)
2.8V (120%)
Float 3 days Float 9 days Float 24 days Float 6.5 days GROUP RECHG DCHG6 RECHG DCHG 7 RECHG DCHG 8 RECHG DCHG 9 RECHG DCHG 10 LAST DCHG DS > D6
% of 2 Hrs D6 > D7
% of 2 Hrs D7 > D8
% of 2 Hrs D8>D9
% of 2 Hrs 09 > D10
% of 2 Hrs DATE PVA 2.33V<10A 105.1 2.33V<10A 05-10-96 2.8V (120%)
2.5V (120%)
Float 6.5 days Float "
- NOTE: Group PVA accidently charged at 300A for -10 minutes on 5/17/96 during float between discharge #6 and #7. Ceus to be floated >6 days prior to discharge #7.
GROUP PVA 120 ~ N 110' W
g 100 i
.0 5, so E
70 -
60 DCHG1 DCHG 2 DCHG 3 DCHG4 DCHG5 DCHG6 DISCHARGE s t
consh3pv 1.mert TN PrW
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HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN PA 16-Apr-96 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs D2 > D3
% of 2 Hrs D3 > D4
% of 2 Hrs D4 > DS
% of 2 Hrs DATE A
2.25V/ cell 116.5 Float 104.2 Float 58 days 99.2 Float 14 days 79.7 2.33V to <10A 68.6 02-15-96 780 hrs 70A/4 Hrs 2.8V/4 Hrs 2.8V/4 Hrs Float 11 days Float 8 days Float 7 days GROUP A 120 110
$ 100 i
a 90
-_2_...--
2 EI
{so 70 so DCHG 1 DCHG 2 OCHG3 DCHG4 DCHG5 DISCHARGE #
consho3a Lucent Tec6 Proprietary
s
?
I HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN, PA I
16-Apr-96 i
TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs 02>03
% of 2 Hrs D3 > D4
' % of 2 Hrs D4 > DS
% of 2 Hrs DATE I
B 2.25V/ cell 117.7 Float 103.6 Float 14 days 92.0 2.55V/74 Hrs 81.4 Float 11-08-95 I
69 Hrs 2.60V/73 Hrs Float 6 days i
L I
i I
GROUP B 120 110 N 100 -
i c.
go 5
eg
.0 70 60 DCHG1 DCHG2 DCHG 3 DCHG 4 O4SCHARGE8 congho3b Lucent Technologes Proprietary
HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN, PA 16-Apr-96 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs D2 > D3
% of 2 Hrs D3 > D4
% of 2 Hrs D4 > DS
% of 2 Hrs DATE D
2.25V/ cell 119.9 F! oat 106.5 Float 60 days 92.5 Float 43 days 78.5 2.33V to <10A 63.5 02-15-96 168 Hrs 2.8V/4 Hrs 2.5V/8 Hrs Float 8 days Float 7 days GROUP D
- 120, 110
- - - ~ -
p 100 E
o i3 e
g 80 70 60 DCHG1 DCHG 2 DCHG3 DCHG4 DCHG5 DISCHARGE #
consho3d 1.ucent Techno6 ogres Proprietary e
HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN, PA 16-Apr-96 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs 02 > D3
% of 2 Hrs D3 > D4
% of 2 Hrs D4 > DS
% of 2 Hrs DATE E
2.2SV/ceit 112.5 70A/20 Hrs 110.5 70A/20 Hrs 109.6 70A/20 Hrs 100.3 70N20 Hrs 88.4 01-16-96 SN72 Hrs SA/72 Hrs Float 17 days SN72 Hrs Float 8 days Float 10 days Float 7 days GROUP E 120 110-
^
g too.
1 ig go. _._:____
eg u.
70 so DCHG1 DCHG2 DCHG 3 DCHG 4 DCHG5 DISCHARGE #
corisho3e Lucent Technologies Proswietary
t s
HIGH GRAVITY ROUND CELL TEST STATUS CONSHOHOCKEN PA 16-Apr-96 TEST
SUMMARY
GROUP RECHG DCHG 1 RECHG DCHG 2 RECHG DCHG 3 RECHG DCHG 4 RECHG DCHGS LAST DCHG DO > D1
% of 2 Hrs D1 > D2
% of 2 Hrs D2 > D3
% of 2 Hrs D3 > D4
% of 2 Hrs D4 > DS
% of 2 Hrs DATE F
2.25V/ cell 117.9 Float 110.9 Float 5 days 107.5 2.6V/73 Hrs 85.6 Float 11-08-95 24 Hrs Float 6 days GROUP F 120 110-g too 1
ig go 6
e.o r
70 -
I N
DCHG1 DCHG2 DCHG 3 DCHG4 f
DISCHARGE #
I l
I i
cdnsho3f Lucent Technologies Propnetary
=
~ - - _. ___ _
i 4
- HIGH GRAVITY ROUND CELL EST DATA CONSHOHOCKEN, PA May 20,19%
PERFORMANCE AS PERCENT OF 2 HOUR DISCHARGE RAW AFTER RECHARGE AT 2.25 VOLTS / CELL i
BATTERY ID DAYS BETWEEN PERCENT CAP.
PERCENT CAP.
PERCENT (DSCH #)
DISCHARGES BEFORE RECHG AFTER RECHG RETAINED GROUP F 1
117.9 110.9 94.1 (12)
GROUP C 2
117.9 108.4 91.9 I
(1-2)
GROUP B 3
117.7 103.6 88.0 (1-2)
GROUP F 5
110.9 107.5 96.9 (2-3)
GROUP D 7
119.9 106.5 88.8 (1-2)
GROUP B 14 103.6 92.0 88.8 i
(2-3)
GROUP A 32 116.5 104.2 89.4 (1-2)
GROUP D 60 106.5 92.5 86.9 l
(2-3)
GROUP C 177 98.6 91.8 93.1 (3-4)
RECHARGE AT 2.33 V/ CELL GROUP C 3
91.8 83.4 90.9 (4-5) i 1
I I
confloat 1
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~
AT&T Round Cell Nuclear Utility User's Council Charlotte, NC May 22,1996 l
8:00 a.m. - 6:00 p.m.
4
]
Electric Center l
526 South Church Street i
Charlotte, NC l
Room #ECII-1270 Extension: 382-3075 1
4
Agenda Topics -----
d i
- 1. Review and Adopt Charter W N Matthews 8:00-9:00 AM
- 2. Review Historical Problems and Lessons GPU 9:00-11:30 AM Learned (Expectations #4) i
- 3. Lunch 11:30-12:30 PM
- 4. Discuss and Establish a Position on the APS Following: (Expectation #1)
A. Battery Degradation 12:30-3:00 PM l
B. Preferred Charging Methods 3:00-5:00 PM
- 5. Discuss any On Going or Planned Low Specific Lucent Technologies 5:00-6:00 PM Gravity Cell Testing i
4 Other information u
~
AT&T Round Cell Nuclear Utility User's Council Charlotte, NC May 23,1996 8:00 a.m. - 3:00 p.m.
Electric Center l
526 South Church Street l
Charlotte, NC l
Room #ECII-1270 j
Extension: 382-3075 1
l i
j
Agenda Topics -----
i i
following: (Expectation #1) cont'd
{
C. Battery Perfonnance Test Acceptance j
Criteria l
- 2. Lunch 11:30-12:30 PM
- 3. Identify and Determine Applicability ofIEEE COMED 12:30-2:30 PM l
Standards (Expectations #3) i 4.
Establish Next Meeting, Date, and Location 2:30-3:00 PM j
- 5. Adjourn 3:00 PM l
Other information
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PHONEL Q14)264 2eee FAX. G14)2444te2 Mr. Kurt Uhler Comed Braidwood Nuclear Plant i
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Department ofNuclear Engineenng Senices 1400 Opus Place 4th Floor Dowrers Grove D. 60515 December 6,1995 Kurt:
Regardmg your question about allow 2ble electrolyte levels.in the list ISH Round Cells used in your plant, I would like to gim the following comment.s-
%ere is considerabic excess amount of electrolyte available in the Round Cell, relative to the active efectrode matenals and therefore the amount of electrolyte and consequently the electrolyte icwl could vary over a relatrvely wide range without impeding the perfonnance l
However, th concentration of the acid in the ciectrolyte is not allowed to vary over a wide range.
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This is the purpose of having the electrolyte level markings on the RaudCell, which could indicate that the concentration of acid has become too high due to loss of water from evaporation or electrolysis (electmlyte level below low level line), or too low because of water addition by maintenance penannel (elec:rolyte level above high level line). The indicator for acceptable acid concentration is the specific gravity of the c!cctrolyte of a fully charged cell.
Ano6er reason for change in tbc electrolyte Icvel, which does not affect the acid concentration, is the amount of gas geocrated during float charge and which is trapped within the l
electrode awmbly in the cell. This amount of gas depcods on the float current and increases with l
l temperature of operation and with chargieg voltage. Because the concentration of the acid is not affected, the allow 3ble variation of the electrolyte level in this case is much higher and is only limited by the cntena that the electrolyte should cover fully tle top plate in the cell and should oo(
l wet the jar to cover seat area. It should be noted that raising the voltage to the boost charge voltage i
of 2.5V/ cell may increase the electrolyte level from 1/2 to 1 inch, due to inemased gas entrapment.
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Based on the discurs;on abe've the electrolyte level requirements for the Roend Cells can l
be altered as follows.
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i The upper level electrolpe roark can be raised by 1/4 inch with electrolyte levels of 1/4 inch above this new mark still being witaNe, provided the conditions listed below are rnet.
- 1. 'Ihe speci6e gravity of the electrolyte is wnhm specineation. (It rnay take up to several weeks to obtain unifonn acid disuibution in the cell following a discharge end recharge.)
- 2. Femman for the increased electrolyte levels are understood 3.
If an additional boost charge is required the electrolyte levels will not reach the jar to cover seal during this process.
I With regards, l
Fred Laman AT&T Bell Laboratories Mesquite TX.
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i Agenda Topics AT&T Round Cell Nuclear Utility User's Council July 30-31,1996 Chicago, Ill.
Old Business Discussion on the pmper temperature derating factor to use with the Round Cells.
Status update on Expectation # 1," Evaluate charging methods for high specific gravity Round Cells". Note scope increase to include examining the impact of shallow repetitive discharges.
l (Sponsor-Mr. Hypes)
Finalize position paper for Expectation # 3," Identify and detennine applicability of IEEE Standards". (Sponsor-Mr. Hypes) l l'
New Business Report on Expectation # 5," Develop position on testing and coiTelation of internal cell l
impedance / resistance to cell performance". (Sponsor-Mr. Koenig)
Status report on Expectation # 8," Investigate root cause(s) of Palo Verde and Braidwood battery capacity loss". (Sponsor-Mr. Hypse/Mr. Koenig)
Status report on progress of low specific gravity cell testing. (Sponsor-Mr. Weeks) 1 I
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[n 11 1
- J Duke Power Company 4TTA/AMET B l
Pa sox /008 Charlotte, NC 28201 1006 DUKE POWER February 1,1996 l
l Secretary,IEEE Standards Board 445 Hoes Lane P.O. Box 1331 Piscataway, NJ 08855-1331 l
Subject:
IEEE Std 450-1995 Sections 5.2 (c) and 7 IEEE Std 485-1983 Section 6.2.3 Round Cells
Dear Mr. Secretary:
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Duke Power Company uses IEEE Standards 450 and 485 as a guideline for technical j
specifications, maintenance, testing, replacement, and sizing oflead-acid batteries. The NRC has raised some concerns regarding technical specifications for Round Cells. The technical specifications under discussion are based on IEEE Std 450 Sections 5.2 (c) and 7 and IEEE Std 485 Section 6.2.3.
A Round Cell Owners Group has recently been established. Duke Power would appreciate if the Battery Working Group would consider input from this group and provide an interpretation ofIEEE Std 450 Sections 5.2 (c) and 7 and IEEE Std 485 Section 6.2.3 as it applies to Round Cells.
Sincerely yours, Walter A. Wyh Nuclear Production Engineer Nuclear Generation Department Duke Power Company waw 1
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