ML20072K531
| ML20072K531 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 06/14/1983 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Sternberg D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ANPP-24074-BSK, DER-83-11, NUDOCS 8307060323 | |
| Download: ML20072K531 (9) | |
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r, PECElvgg ima Arizona Public Service Company P O. BOX 21606.
PHOENIX, ARIZONA W~~ A") 2 7 pq g: gn p June 14, 1983
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U. S. Nuclear Regulatory Commission Region V Creekside Oaks Office Park 1450 Maria Lane - Suite 210 Walnut Creek, CA 94596-5368 Attention: Mr. D. M. Sternberg, Chief Reactor Projects Branch 1
Subject:
Final Report - DER 83-11 A 50.55(e) Reportable Condition Relating to Exide Batteries May Leak Or Corrode At Terminals Due To Cracking Of Plastic Seals / Covers.
File: 8 3-019-026; D.4.33.2 Re ference: A) Telephone Conversation between A. D'Angelo and G. Duckworth dated February 28, 1983.
B) ANPP-23348, dated March 24, 1983 (Interim Report)
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e).
Very truly yours,
.L CQ1.
ALM E. E. Van Brunt, Jr.
APS Vice President, Nuclear Projects Management ANPP Project Director EEUB/RQT:ru Enclosure cc:
See Page 2 8307060323 830614 PDR ADOCK 05000528
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U. S. Nuclear Regulatory Commission Page 2 cc: Richard DeYoung, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 T. G. Woods, Jr.
G. C. Andognini J. A. Roedel-
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B.'Fasnacht A. C. Rogers B. S. Kaplan W. E. Ide J. Vorees J. R. Bynum P. P. Klute/D. D. Green A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher R. M. Grant D. R. Hawkinson L. E. Vorderbrueggen G. A. Fiorelli S. R. Frost Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway - Suite 1500 Atlanta, Georgia 30339 i
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FINAL REPORT - DER 83-11 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNITS 1 & 2 I.
Description of Deficiency An Exide letter dated 1/31/83 (attached), noted the PVNGS project has been notified of two ninor faults existing in Exide stationary 125 volt G-cell batteries impacting the long term serviceable life of the battery. These batteries are used at PVNGS to provide a backup source of DC power for the Class IE 125 V DC power system, which supplies power to reactor trip switchgear and vital instrumentation as well as to reactor protection and engineered safety features systems. The two identified faults exist in those G-cell batteries produced before August, 1982.
The first fault centers around the terminal post seals and the components and materials which combine to make the seals.
The design of the seal involves the compression of a rubber sleeve, or gland, against the lead terminal post. The gland is held in compression by the cover and the seal nut.
Applied stress on these plastic components could cause them to crack, thereby allowing the seal to leak. This would allow acid to migrate up the posts The second fault is that a nodular corrosion of the lead post, which can take place if the cracking in the plastic parts above is only partial or if the compression of the gland is marginal to begin with.
(Note:
If cracking of the plastic parts above is complete, the battery will allow acid leakage, under which conditions nodular corrosion does not take place). This corrosion takes place in the crevice of a partially tight seal and causes a growth to take place on the surface of the lead. The consequence of nodular corrosion is to create additional stress on the plastic components, this time in a radial direction, which can lead to radial cracks in the cell cover.
II.
Analysis of Safety Implications As indicated in the attached letter, the safety and performance of the battery would not be affected during its early years of life.
The evolution of acid leakage or nodular corrosion could readily be detected and monitored during the recommended maintenance activities which are contained in Exide's Instructions for Installing and Operating Stationary Batteries, Items 1, 4, and 5 (Reference Bechtel Log No. 13-10407-E0 50-8 8-1). If left uncorrected the faults would decrease the expected life of the battery, requiring battery replacement rates greater than originally intended. However, the decrease in serviceable life expectancy of the batteries would not adversely affect the safety of operations of the plant at any time since battery surveillance and testing is a mandatory ongoing plant maintenance activity. There fore, this condition is evaluated as not reportable under the requirements of 10CFR50.55(e).
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i-y l' Final Report - DER 83-11 Page 2 III. Corrective Action A procedure for the permanent repair of the subject batteries has been developed by Exide.
It is based upon the principle of eliminating all stresses on the plastic parts and creating a new seal of stress-free design abvove the old seal. An outline of the procedure, given in Section 4-B of Attachment 1, is as follows:
1.
Disconnect and remove all intercell, intertier and terminal Connectors.
2.
Remove all red and black terminal seal plastic nuts.
3.
Remove rubber glands from inside the seals.
4.
Rebuild the seals using "0" rings with liquid sealing compound and new red and black caps.
5.
Clean connectors and terminal posts and reassemble hardware in accordance with instructions including micro-ohmeter readings.
6.
Return the battery to service.
This procedure will not only correct the primary fault by reducing stress, but will also correct the secondary fault if it exists. Any nodular corrosion present will be " quenched" if allowed exposure to the acid in the cell. Unit 1 and 2 batteries will be corrected at the jobsite prior to fuel loading by Exide personnel using their corrective action plan. Unit 3 batteries will be corrected prior to delivery.
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ATTACHMENT T'O DER 83-11 January 31, 1983 ARIZONA PUBLIC SERVICE CCMPANY l
P.O. Box 21666, Mail Station 3003 Phoenix, AZ 85036 Attention: Manager Nuclear Services
Reference:
Arizona Public Service Co.
Palo Verde Project, Units 1 and 2 Purchase Order 10407-13-EM-050 Batteries Gentlemen
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Tau vin find attached, a position paper covering the class II batteries as covered by your referenced order signed by Mr. W. E. R. Jones, Vice President - Engineering for Ezide Corporation.
Sincerely, e* d 2,)
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Cs. seichart Contract Administrator QA 4 agg k
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EXIDE
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NOTICE TO OPERATORS OF EXIDE GN CLASS 1E BATTERIE5_
1.
MINOR FAULTS DISCOVERED Two minor faults have been discovered by EXIDE in G-cells produced before August These faults may be present on some or all GN batteries qualified for Class 1E service, even though, in most cases, there may be no visible evidence of 1982.
While the faults will not affect the safety or the performance of the battery, at least in its early years of life, EXIDE believes it is prudent to the faults.
effect an on-site correction as soon as reasonably possible, to pre-empt any hazard from developing.
2.
THE FIRST FAULT _
The fault centers around the teminal post seals and the components and materials which combine to make the seals.
The design of the seal (see Fig.1) involves the compression of a rubber sleev or gland, against the lead teminal post.
cover and the seal nut.
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Unfortunately, the stress on these plastic components, over a period of years, can The plastic boss at the base of the seal can crack as shown
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cause them to crack.
in Fig. 2, or the seal nut can crack as shown in Fig. 3.
The effect of either type of cracking is the same in that it relieves the pressure on the gland, thereby allowing the seal to " leak", that is, to allow acid to Given that the intercell connectors are tight, as migrate slowly up the posts.
they should be, this leakage should cause no problems.
A procedure has been developed for pemanent repair, which is now being refined, This can be and submitted for qualification, for reducing the rate of the leakage.
carried out on site by EXIDE personnel, and should be implemented during your next
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planned shutdown.
It is based on the principle of eliminating all stresses on the plastic parts, and j
creating a new seal, of stress-free design, above the old seal location.
3.
SECOND FAULT l-The cracking of the plastic boss or nut, if com11ete, causes nothing more thanIf the crackin leakage, which, as stated, can be reduced by otler means. partial, or the l,
This corrosion takes fault, called " nodular corrosion" of the lead post can occur.
place in the crevice of a partially tight seal and causes a growth to take place on the surface of the lead.
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Page 3 NOTICE TO OPERATORS OF EXIDE GM CLASS 1E BATTERIES l
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A final corrective action, necessary only for the few units which_ have radial This relatively simple cracks in the covers, is a " flood-pour" cover repair.
technique creates an all-enveloping secondary cover above the old o sealing off any cracks.For small, isolated cracks, individual repair is prefereable.
cracks are present.
W. E. M. Jones, Jr.
Vice President Engineering WEMJ:jeb
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Page 2 NOTICE TO OPERATORS OF EXIDE GN CLASS 1E BATTERIES _
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Nodular corrosion does not take place in the presence of acid and is, therefore, avoided if the seal " leaks" slightly.
The consequence of nodular corrosion is to create additional stress on the components, this time in a radial direction.A small number of cells have been reported in the cell cover (Fig. 4).
condition.
4.
CORRECTIVE ACTIONS _
A) HOLDING POSITION Until such time as we can effect pennanent repairs, which we plan to do usin EXIDE personnel supervised by Headquarter's Engin They should be Taken together, they will ensure integrity of the battery.
carried out expediently.
Back off all red and black nuts to eliminate any renaining gasket com-1.
pression of the post seals.
Retorque intercell connector bolts to 250 in, lbs.
2.
Ensure that teminals are fully coated with No-oxide grease.
Repair any cracks in the covers with approved cement, after appropriate 3.
4.
cleaning and neutralizing.
Conduct micro-ohmeter check on all intercell connections and arrange for
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this check to be repeated quarterly by EXIDE personnel or until 5.
repairs have been completed.to 250 in. lbs. as well as a thorough and covers for further cracks.
'l This procedure will not affect our qualification.
NOTE:
PERMANENT REPAIRS B) _During shutdown,effect pemanent repairs as follows:
j Disconnect and remove all intercell, intertier and teminal connectors.
1.
Remove all red and black teminal seal plastic nuts.
2.
Remove rubber glands from inside the seals.
Rebuild the seals using "0" rings with liquid sealing compound and new 3.
4.
s red and black caps.
Clean connectors and terminal posts and reassemble hardware in accordanc l
5.
with instructions including micro-ohmeter readings.
6.
Return the battery to service.
This procedure will not only correct the primary fault, by reducing stress will also correct the secondary fault if it exists.
will be " quenched" if allowed exposure to the acid in the cell. -
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,l The pemanent recairs cannot be undertaken until we have completed the I
l re-qualification of the liquid seal planned for July 1983, NOTE:
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