ML20037B239
| ML20037B239 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Byron, Braidwood, Quad Cities, Zion, LaSalle  |
| Issue date: | 04/05/1977 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8009090878 | |
| Download: ML20037B239 (1) | |
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CENTRAL FILES in.?
m APR 5197T Docket Noa. 50-10, 50-237 6 50-249 Dochet 1:o9. 50-254 ( 50-265 Dochet ton. 50-295 & $0-504 Dochet !<es. 50-373 t. 50- 374 Docket Hon. 50-454 & 50-455 Docket ilos. 50-455 t 50-457 Cormonwealth Edison Cowany KIT!: Mr. Byron Lee, Jr.
Vien President P. O. Box 767 i
Chicago, IL 00690 c ntlement e
h enclosed Circulcr is being distributed for information, in the belief that the subject matter io of sufficient asfety significt.nce to warrant specific attention. A reply il not requested.
i Sincerely, lt 1
Jates G. Ecppler a
Director i
Eaclocure:
IE Circular No. 77-06, " Effects of I
Hydraulic Fluid on 4
Electrical Cables" cc u/cnel:
fir. U. D. Stephenson.
Mr. G. Sorencen, Site Station Superintendant Project Superintendent Mr..!. KalivianaMet.
Iir. R. Cor:aro. Site Station Superintendent Project F.uperlatendent Mr. J. Ditel, Plant Central Files
, Superintendent
!!cproduction Unit 1;KC 20b
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Mr. L. J. Burke, Site PUR Project Superinter. dent Local PDR Authony Poiratn, Ecr,,
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O, IE Circular No. 77-06 hpril 5, 1977 EFFECTS or llYDRAULIC FLU 1D 0:: ELECTRIC L CABLES 1)ESCRIPTIO:: OF CIRCUMSTA'CES:
Commonucalth ' Edison Company, by letter to the !!RC dated April 1,1976, (copy enclosed), described the circumstances under which fire resistant hydraulic fluid had a Acleterious effect on the innulation and jacketing of electrical cables.
b'hile the solvent characteristics of phosphate-cater fire resistant fluids arc well documented in literature, it appears that this infornation may not be cencrally available to nuclear power
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plant operating staffs.
Our evaluation of this occurrence emphasizes the importance of:
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Reviewing design and operating procedurcs for systems containing synthetic hydraulic fluids and other'potentially aggressive iluids.
te minimize the probability of leakage, overflow or inadvertant spfil of' fluid.
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Revicuing housckceping practices to e.ssure that they provide for prompt cleanup of spills or leakage of any type of fluid.
Enclosure:
1,ctter f rom Cor. mom:calth ' Edison Co.
to J. Keppler, Director, Region III dtd. 4/1/76 e
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HJr-76-il8 April 1, 1976 J. Keppler, Regional-Director Office of Inspection and Enforcement Regl,on iII U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 quad-Citics Nuclear Power Station.
Reference:
Docket No. 50-265, DPR-30, Unit 2
, in response to.your inspection Report No. 050-265/76'-04, the follcwing report concerning possible gencric problems related to Electro-Hydraulic Control (EHC) system oil migrating to the cable tunnel area is being submitted.
On October 9, 1975, station personnel were cleaning up EHC fluid which had been dripping on the Unit 2 cable tunnel floor.
It was noticed not only had th'e EHC fluid been leaking onto the ficor but also it had been leaking onto the cables in the surrounding cable pans.
Closer inspection.
of the cables revealed puffing and plasticization of cabics that the EliC fluid had made contact with.
At the time of discovery, Unit 2 was in the cold shutdown condition.
Cables l'n the Unit 2 cabic tunnel were utilized for both safcty related end non-safety related functions.
The Elic fluid icok had not rendered any safety or non-safety related systems inoperabic.
The it:cediate action taken was to determine the extent of plastici2ation of the af fected cabics.
All the cables and cable pans in the affected arca of the Unit 2 cable tunnel were cleaned with a soap and water solution as recorrmended by information from the EllC fluid manufacturer.
The cicaninq of EllC fluid from the cables shoild climinate further effects of plas-ticization.
A small section of control cable, which was hand traced to identify its function, was cut out and analyzed, it was discovered that only the overall jacketing material had been affected by the CHC fluid.
Various cabic mansuf acturers and the manuf acturer of CHC fluid werc censulted 05 to the f:ficct s of fl!C fluid on viirlous polymers used for cable.
Poly
- vinylchloride (l'VC) and neopr ene were found to be af fer.t ed severely t,y 01:0 fluid..nd not r e c. n:c.r.c n d e d (br n;c around fift fluid.
Other polymers f.u c h a, r.u l y c t b y 1. n e, 1eflon. ' i l i t.nn e rubber, nylon,.ind butyl rubber were a c c ep :.ib i c t or er:.c around fit; fluid.
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The next course of action was to determine ti c types of cabic in the Unit 2 cabic tunnel that were' af fected by the Clic fluid.
The types of cable construction were categorized as foilows:
Control & Power (low voltage):
Individual or multiconductor PVC l.
Jacketed; mylar wrapped, PVC,over butyl rubber insulated conductors.
7.
Instrumentation:
PVC jacketed, shleided, mylar wrapped,' polyethylene insulated conductors.
Instrumentation:
Single end multiconductor PVC Jacketed, polyethylene 3
Insulated, mylar wrapped and shicided twisted pairs.
4.
Instrumentation:
PVC Jacketed, polyethylene insulated, coaxial cabic.
The control and power cables comprised approximately 80% of all cables in the Unit 2 cable tunnel.
Close inspection revealed that the EHC fluid had not permeated through the PVC overall Jacket.
Since butyl rubber is not af fected by EHC fluid, it was' recommended that these cables be cleaned and Icft in place after the cabic pans were cleaned out.
The Instrumentation cables as described abov' in cases 2 and 3 revealed that'some saturation through the overall PVC jacketing resulted.
- However, in no cases had the EHC fluid permeated through the mylar shiciding covering.
It was recommended tnat the plasticized sections of Jacketing be removed and a suitable Jacketing tape be applied.
consisted of coaxial nuclear instrumentation Case 4 as described above, The coaxial cables' overall jacketing is very thin and consequently cables.
Plasticization had suffered greatly from the effects of plasticization.
interference exposed the shieldino conductor, such that possible electrical could result.
The coaxial cables' functions were as follows:
s 1.
Local Power Range Monitoring (LPRM)'
2.
Int 5rmediate Range Monitoring (IRM) 3 Source Range Monitoring (SRM)
Since there were only 90 coaxial cables affected by the EliC fluid, it was recommended to splice in new coaxial cable sections and not tape over the in ti;is case was considered more acceptable than taping.
shielding.
Splicing All coaxial cables were identified and labeled before splicing was permitted.
The coaxial cables were tested against acceptabic electrical properties after being spilced.
Figurc 1 shows the approximate locations where EHC fluid accumulated.
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the Figure 2 illustrates the postulated path of EllC fluid migration from EltC fluid reservoir to the tinit 2 cable tunnel area.
The accumulation of EllC fluid around the CHC fluid reservoir foundation, and subsequent finish floor and rough slab, via small cracks in nigration betwnen the the concretc. i t. the postulated cause of the CIIC fluid problem.
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Th2 rough slab serves as the ceiling in the Unit 2 cabic tunnel and mln:r small cracks in the ceiling served as a 1,*nk path out of the concrete I
cod onto the cabic trays and floor.
Portioni of cabics within these trays thus became saturated with the EllC fluid.
The upper cabic trays did not contain al'1 of the EllC fluid, even though This was the pans in the cabic tunnel were of solid bot tom construction.
because the Ell; fluid had Ic iked through the cnble pan connecting joints cnd thus all the cable pans below were subje.ted to the EllC fluid.
The c:bles closest to the bottom of the cabic p.ms were inost af fected by the EHC fluid because these cabics were i n constant saturation with EHC flui '.
At the prc'sent time, all the cabics in 'the affected'arca of the Unit 2 cable tunnel are being protected f rom the continuing EllC fluid Icakage.
Tha leakage has subsided and once it has stopped the ceiling arca will bc cleaned and a protective scaler will be applicil to prevent any possibic leakages.
Tha EHC fluid reservoir-foundation must also be scaled with the same protective scaler once Icakages have been resolved.
The scalcr has been crdered from the Carboline Company, type 107 lirP,.which is a recommended EHC fluid scalant.
Tha station's technical staff has been per form 1.ng a weekl'y inspection of the Unit 2 cable tunnel to assure that thern is no leaking onto the cables.
A representative from the Region III, U. S. Hocicar Regukatory Commission rzviewed the work package associated with the r epairs and discussed his findings with t,he station.
If further information is desired, please contact the station.
Sincerely yours,
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H. J. Kallvianakis Station Superintendent Quad-Cities Nuclear Power Station HHJtt'H/1k 9
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