ML19208D030
| ML19208D030 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/20/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Stello V NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-79-145-000 NUDOCS 7909270766 | |
| Download: ML19208D030 (2) | |
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U1 Docket No. 50-336 Mr. V. Stello, Jr.
- Director, Office of Inspection and Enforcement U. 3. Nuclear Regulatory Co==1ssion Washington, D. C.
20555 G entleme.1:
Millstone Nuclear Power Station, Unit Sc. 2 Main Station Ectteries Iursuant to eporting requirements of 100FR Part 21, 1.cethenst.M:1 car Energy C:- eny (NN' ;0) is hereby advising the FRC Staff of the cprarent det:2 cation cf the c=crp acy D.C. Main Station En tcries.
Thcse batteries cr cf the iced calcium typ., model LCU-33 supplied by CSD 3atteries.
F;ysical inspection of the batteries has identified a breakdev cf the lead u_.uding surrounding the copper (positive) terminal pest :=.. ;. 2 3 t.; rough the cc11 top.
This allows the battery acid to come in cont:ct 1ith t'- cepper tc= inal pssc, which is gradually deccc: posing. The decomposed cep pt cen c.nat.cs O.e S:::ery cell and collects on the battary plates, shorting t'. 2: cut end reducin;
.; cell's voltage. This corrosion, in the absence of correc;_,a a:tica, coul:.
ulticately result in the loss of the battery connecticn.at tha cell sitive
- rrint.1 creating a loss of safety lunction.
20*ECO h s det;c ir. ' H.: thi
- tenti:1 degradation constitutes a substantial saf ety h::crd as definad in
.::~.11.3(kj.
This determination was cc=pleted on Aug a: ' :, 13 :, _1:1.m..
in'. as:igatic as had been conducted during the past several weeks.
'illstone Nuclear Power Station, Unit No. 2 is eculppe:. with twc (2), 12f7 :.C.
. -in Statior 2atteries, and each battery is comprised of c0 lead c lcium cells se:nected in series. The battery manufacturer has detenined that the deterieratier cf the lead cladding is due to a complex electrolyte /1?id interactic :nnsed
.he use of an "0" ring seal compressed around the te = in:1 pcst.
..... c c11 a fer both batteries have been ordered from C&D. The ncr c. ells will ' n a s c '. i feuign utilizing a close tolerance lead sleeve inst'- -
- ruht 104209I 490927p g
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. he lead sleeve will be heli-arc welded on its top surf ace to the terminal post as it exits the seal. This design has been used on all large batteries supplied cy CID over the past five years without reported problems replacing the old "0"
ring design.
The replace =ent cells are scheduled to be delivered to the site within the next several weeks and replacement will be af fected as expeditiously as possible.
T,egarding plant operation in the interim, it has been concluded that the existing batteries are suitable for continued operation as they continue to fulfill their design function, meeting the applicable requirements of Station Technical Specifications.
In addition, NNECO lists the following basis for continued operation:
(1) Two cells which had the lowest voltage measurements and highest visible decomposed copper products, were replaced with new cells manufactured by C&D.
(2) l';:n testing these degraded cells, they were found to exhibit becter than their 1007. rating during a full discharge test to deterndne the cna (1) einute and eight (S) hour rating.
L er=inal post connecticas, althcugh partly creded, were cuf ficient ::
- rry the full discharge current.
- is estics:c. tha: the crca en ucu:-
.2"e to be 100% greater than that found before current car r; _.. - capaci:;
.:21d be affected.
i, "c cells will re=ain in serrice with greater n run: uf cer.
.cr produe:2 than those cells removed in Itc2 (1).
3 3::h of the existing batteries underwent a successful eight s;
.. ur discharge test in April,1979.
2, Increased visual and test surveillances have bccn initiatec tc ensure th:t degradation does not precced beyond the point of :hese :llis whici.
- rere recoved.
The time to complete the replacement is not expe".tcc to excee; :.c
=c a t:2.
'.: b ::ery v( dor has indicated that no other facili::. hcs been s r:12ad wi:2
- f2;;;rd batteries of this design.
The resident :a; Inspector h:2 ceen (2;;
-77:isc; of recent developments regarding the station batteries.
.; trust
. in..his infor=ation sufficient to fulfill the notification requir;;ents c2
-._TL Part 21.
Very truly ycurr,
- 0 2.TH E^. S T T'" ~ ' " "Y C '
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..e, ATTACHED IS A PART 21 REPORT FROM IE FAIL UNIT - ROOM 359E/W PART 21 IDBRIFICATION to.
7 9-w-= c COMPANY taE A=-
r DATEOPLETIER 3Aa> s DOCET t0.
e - i : c-DATEDISTRIBUTED(/Lu7e ORIGItMLPEPORT A SUPPLEEHARY DISTRIBUTION:
REACTOR (R)7 REL CYCE &
SeEtGU@S(S) f%TERIALS(M)
NRR/ DOR, DIRECTOR AD/ FREI -
AD/SG-IE GRR/DR4 DIPECTOR t!GS/FGE AD/RDI AD/RDI ( 2 )
PEGI0'lS FEGIO:G AS/RCI IE FIES NPF/DADIFECTOR
?EGIO:iS EDR KGS/S5 SS-SSI IE FIES (2)
LPDR ER CE,TPAL FILE 5 CBEPAL FIES-SS-395 LPDR CEU?AL FIES (CHR000 CSUFAL FIESCCHR0:0 T8A IEFIlls(2) lEPA L DR CEEPAL FIES 015 TE?A S03DBdIG, PPA CEEPAL FIES (CHRD'O 3333.gg13,apA CEH?AL FIES - SS-395 ACTIO:h E JEGIG, IPA PROLIMINARY EVUALATION OF die ATTACHED REPORT IfDICATES LEAD RESD0t!SIBILITY FO FO'J.OV-UD AS SH0hN BELG4:
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