ML17054D004

IE Circular 77-06, Effects of Hydraulic Fluid on Electrical Cables

ML17054D004
Person / Time
Site:	Crane
Issue date:	04/06/1977
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
Shared Package
ML17054D005	List: ML17054D004 ML19206A419 ML19206A439
References
IEC-77-6, NUDOCS 7904200026
Download: ML17054D004 (16)

Text

NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.

C.

20555 IE Circu'1ar 77-06 Date:

April 5, 1977 Page 1 of 1 EFFECTS OF HYDRAULIC FLUID ON ELECTRICAL CABLES DESCRIPTION OF CIRCUMSTANCES:

Commonwealth Edison Company,'by letter to the NRC dated April 1, 1976, (copy enclosed),

described'he circumstances under which fire resistant hydraulic fluid had a deleterious effect on the insulation and jacketing of electrical cables.

While the solvent characteristics of phosphate-ester fire resistant fluids are well documented in literature, it appears that this information may not be generally available to nuclear power plant operating staffs.

Our evaluation of this occurrence emphasizes the importance of:

1.

Reviewing design and operating procedures for systems containing synthetic hydraulic fluids and other potentially aggressive fluids to minimize the probability of leakage, overflow or inadvertent spill of fluid.

2.

Reviewing housekeeping practices to assure that they provide for p} ompt cleanup'f spills or leakage of any type of fluid.

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Enclosure:

Letter from Commonwealth Edison Co.

to J. Keppler, Director, Region III dtd. 4/I/76

Comlnoni~ llh Edison

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Quad-Cihcs~lear Power Slahon Po" l Qlfice Box 216 Cordova, Illinois61242 Telephone 309/654-2241 NJK-76-118 Apri 1 1,

1976 J.

Keppler, Regional Director Office of Inspection and Enforcement Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Reference:

Quad-Cities Nuclear Power Station Docket Ho.. 50-265, DPR"30, Unit 2 ln response to your Inspection Report Ho. 050-265/76-04, the following Control (EHC) system oil migrating to the cable tunnel area is being submitted.

On October 9, 1975, station personnel'ere cleaning up EHC fluid which had been dripping on the Unit 2 cable tunnel floor.

It was noticed not only had the EHC fluid been leaking onto the floor but also it had been leaking onto the cables in the surrounding cable pans.

Closer inspection of the cables revealed puffing and plasticization of cables that the EHC fluid had made contact with.

At the time of discovery, Unit 2 was in the cold shutdown condition.

Cables in the Unit 2 cable tunnel were utilized for both safety related and non-safety related functions.

The EHC fluid leak had not rendered any safety or non-safety related systems inoperable.

The immediate action taken was to determine the extent of plasticization of the affected cables.

All the cables and cable pans in the affected area of the Unit 2 cable tunnel were cleaned with a soap and water solution as recommended by information from the EHC fluid manufacturer.

The cleaning of EHC fluid from the cables should eliminate further effects of plas-ticizat'ion.

A'mall section of control cable,'hich was 'hand traced.to" identify its function,'as cut out and analyzed.

It was discovered that.

only the overall jacketing material had'een affected by the EHC fluid.=...'..

Various cable'anufacturers and the manufact'urer of EHC fluid were consul <<d as to the effects of EHC fluid on various polymers used for-cable.

Poly-vinylchloride (PVC) and neoprene were found to be affected severely by EHC fluid and not recommended for use around EHC fluid.

Other polymers such as polyethylene, teflon, silicone rubber, nylon, and butyl rubber were acceptable for use around EHC fluid.

0

The next. course of action was to determine the types of cable in. the Unit 2 cable tunnel that were affected by the EHC fluid.

The types of cable

'onstruction were categorized as follows:

l Contro1 6 Power (low vol tage):

individual or mul ticonductor PVC

'acketed; mylar wrapped, PVC.over butyl rubber insulated conductors.

2.

instrumentation:

PVC jacketed,

shielded, mylar wrapped, 'polyethylene insulated conductors.

t 3-instrumentation:

Single and mul ticonductor PVC jacketed, polyethylene Insulated, mylar wrapped and shielded twisted pairs.

instrumentation:

PVC jacketed, polyethylene insulated, coaxial cable.

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 affected by EHC fluid, it was'ecommended that these cables be cleaned and left in place after the cable pans were cleahed out.

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The instrumentation cables as described above in cases 2 and 3 revealed that some saturation through the overall pVC jacketing resul ted.

However, in no cases had the EHC fIuid permeated through the mylar shielding covering.

tt was recommended that the plasticized sections of jacketing be removed and a suitable jacketing tape be applied.

Case 4 as described

above, consisted of coaxial nuclear instrumentation cables.

The. coaxial cables'verall jacketing is very thin and consequently suffered greatly from the effects of plasticization.

Plasticization had exposed the shieldin conductor, such that possible electrical. interference could result.

The coaxial cables'unctions were as follows:

I.

Local Power Range Honitoring (LPRH) 2.

intermediate Range Monitoring (IRM)

Source Range Honitoring (SRH)

Since there were only 90 coaxial cables affected by the EHC fluid, it was recommended to splice in new coaxial cable sections and not tape over the shielding-Splicing in this case was considered more acceptable than taping.

All coaxia'I cables were identified and labeled before splicing was permitted-The coaxial cables were t'ested agains't acceptable electrical.propertras

'fter being spliced.

'I Figure I shows the approximate locations where EHC.

fluid'a'ccumulated.

"'igure 2 Illustrates the postulated'ath of EHC fluid migration from the EHC fluid reservoir to the Unit 2 cable tunnel area.

The accumulation

.of EHC fluid around the EHC fluid reservoir foundation, and subsequent migration between the finish flooi and rough slab, via small cracks in the concrete, is the postyiated cause of the EHC fluid problem.

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The rough slab serves as the ceil ing in the Unit 2 cable tunnel and minor small cracks in the ceiling served as a leak path out of the concrete and onto the cable trays and floor.

Portions of cables within these trays

'thus became sa'turated with the EHC fluid.

f The upper cable trays did not contain all of the EHC fluid, even though.

the pans in the cable tunnel were of sol id bottom construction'.:

This was because the EHC fluid had leaked. through the cable

.pan connecting joints and thus all the cable pans below were subjected to the EHC fluid.

The cables closest to the bottom of the cable pans were most affected by the EHC fluid because these cab'les were in constant saturation with EHC fluid.

At the pre'sent time, all the. cables in the affected area of the Unit 2 cable tunnel are being protected from the continuing EHC flui'd leakage.

The leakage has subsided and once it has stopped the ceiling area will be cleaned and a protective sealer will be applied to prevent any possible

'eakages.

The EHC fluid reservoir foundation must also be seal.ed with the same protective sealer once leakages have been resolved.

The sealer has been ordered from the Carboline

Company, type 187 HFP,.which is a recommended EHC fluid sealant.

Th'e station's technical staff has been performing a weekly inspection of the Unit 2 cable tunnel to assure that there is'no leaking onto the cables.

A representative from the Region III, U. S. Nuclear Regulatory Commission reviewed the work package associated with the repairs and discussed his findings with the station.

lf further information is desired, please contact the.station.

'incerely

yours, r

N. J.

Kal ivianakis Station Superintendent Quad-Cities Nuclear Power Station

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UNIT 2 CABLE TUNNEL PARTIAL PLAN UNIT 2'H C Oll RESERVOIR(ELEV ~~5) l22o6

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X-DENOTES

. AREAS NVHERE THE EHC'IL HAD ACCUMULATED REFERENCE DRA)VINO-SARGENT 8 LUNDY M-5

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1 Docket Nos.

50-333 50-220 UNITED STATES NUCLEAR R EG ULATORY COMMISSION REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 March 29, 1977 Niagara Mohawk Power Cor poration

-.ATTN:

Mr. R.

R. Schneider.

Vice President Electric Operations 300 Erie Boulevard West

Syracuse, New York 13202 Gentlemen:

The enclosed IE Circular, 77-05 is.being distributed for information, in the belief that the subject matter is of sufficient safety significance to warrant your specific attention.

No written response is required.

Should you have any questions concerning this matter, please contact this office'. 'incerely, James P. O'Reilly Director Enclosure IE Circular No. 77-05 cc w/encl'.

George.T.

Berry, General Manager and Chief Engineer (PASNY)

Z. E. Chilazi, Manager of Projects, Thermal Power Generation (PASNY)

M. W. Hultgren, Manager, Nuclear Operations (PASNY)

A. Klausman,

Manager, equal.ity Assurance (PASNY)

T. E.- L'empges, General Superintendent, Nuclear Generation (NMPC)

R.

W. Smith, Plant Superintendent (NMPC)

J.

D. Leonard, Jr., Power Authority Resident Manager T.

Roman, Operations Supervisor (NMPC)

M; C. Cosgrove,. guality. Assurance Supervisor (PASNY)

f I

0 Niagara

~bhawk Power Corporation 2

T. 8. Perkins, Station Superintendent C. L. Stuart, Operations Supervisor E. B. Thomas, Jr. ~ Esquire A. Z. Roisman, Counsel for Citizens Committee for Protection of the Environment bcc w/encl:

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