ML20063C191

Interim Deficiency Rept Re Potential Failure of Rockbestos Cable,Initially Reported 820126.Rockbestos Cable in High Temp Environs Will Be Replaced W/Ie Qualified Cable

ML20063C191
Person / Time
Site:	Grand Gulf, Washington Public Power Supply System
Issue date:	04/21/1982
From:	Root R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Faulkenberry R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, G1-82-152, GO1-82-0152, GO1-82-152, NUDOCS 8205040043
Download: ML20063C191 (4)

Text

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', Docket Nos. 50-460/513 o

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)t 50.55 (e) Report G fg

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Washington Public Power Supply System '

P.O. Box 968 3000 GeorgeWashingtonWay Richland, Washington 99352 (Sb9i3g April 21, 1982 UGl0:q,s,.

G01-82-0152 4,

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N Nuclear Regulatory Commission 2 ' '

Region V 8-sa y /g 7 b E ~

1450 Maria Lane, Suite 210 T Walnut Creek, California 94596 A hnenn.k'~Njmj'j hh 6/

Attention: Mr. R. H. Faulkenberry Chief, Reactor Construction k / ,yg / /

Projects Branch

Subject:

NUCLEAR PROJECTS 1 AND 4 DOCKET NOS. 50-460 AND 50-513 REPORTABLE 10CFR50.55(e)

ROCKBESTOS CABLE

Reference:

1) Telecon ME Rodin, Supply System to PP Narbut, Region V, Nuclear Regulatory Commission, dated January 26, 1982

2) G0-1-82-0060, dated February 26, 1982, DW Mazur to RH Faulkenberry In the above referenced telecon the Supply System informed your office of a potentially reportable deficiency under 10CFR50.55(e) and reference

2) was an interim status report on the identified condition.

Attachment A, to this letter, provides the Supply Systems interim report on the above caption condition. The attachment includes a restatement of the problem and an expanded description of the safety implications associated with failure of the Rockbestos cable in the Reactor Protection System. It has been concluded by the Project that a failure of the Rockbes-tos cable in the four Westinghouse Class IE electrical penetrations represents a significant safety problem and as such is reportable under 10CFR50.55(e). At the present time the only cable involved is that used in the Unit 4 penetrations. A review is te be performed of the Raychem cable used in the Unit I penetrations to assure that there is not a similiar problem with that cable. To date, we have been unable to establish a completion schedule for this analysis; therefore, we will continue to provide your office with quarterly interim status reports on the progress of that analysis.

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R. H. Faulkenberry Rockbestos Cable Page 2 If you h y any questions or desire further information, please advise.

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R. W. Root Acting Program Director RWR:MER:lm Attachment cc: CR Bryant, BPA/399 EW Edwards, Bechtel/860 V. Mani, UE&C/896

- V. Stello, Director of Inspection, NRC A. Toth, NRC .

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, ATTACHMENT A WNP-1/4 DOCKET NOS. 50-460 AND 50-513 POTENTIALLY REPORTABLE CONDITION PER 10CFR50.55(e)

ROCKBESTOS CABLE BACKGROUND The Supply System received a letter from Westinghouse Electric Corporation stating that they had been informed by the Rockbestos Company that their solid dielectric coaxial cable exhibited failures under certain conditions.

Westinghouse identified four penetrations (HE2, HH3, HI5, HK3) designated for Unit 4 in which Rockbestos cable was used although they did not know if their application was safety related. In their letter Westinghouse also stated that they had been informed that the NRC was notified of the poter,tial problem. As requested by Supply System Engineering, the AE reviewed the application of the four penetrations in question and determined that they are used for IE circuits at temperatures where failures are likely to occur.

DESCRIPTION OF DEFICIENCY In a letter to Westinghouse, Rockbestos stated that testing confirmed thatcabletypesRSS-6-10gthroughRSS-6-ll2maybesubjecttofailures at temperatures above 230 F. Expansion of the dielectric causes fore-shortening of the braided shield which in turn causes longitudinal compres-sion and kinking of. the center conductor resulting in cracking of the dielectric permitting shorting of the center conductor to the shield.

Westinghouse listed cable type RSS-6-ll2 as used in Unit 4 penetrations HE2, HH3, HI5, HK3.

SAFETY IMPLICATIONS RockbestosrecommendsthattheRSS-6-ll2cablenotbeinstallgdor, if installed, should not be exposed to environments above 230 F. Rock-bestos cable is used in four Unit 4 penetrations to connect the Ion Chambers to the Reactor Prota tion System cabinets (RPS). The RPS initiates a reactor trip when a sensed parameter (or group of parameters) exceeds a setpoint value indicating the approach 'of an unsafe condition. In this manner, the reactor and reactor coolant system (RCS) is protected from over pressurization and f uel cladding damage. The scope of the RPS includes all electronics, signal processing equipment and cabling, from the system sensors to the input terminals of the Control Rod Drive Control System (CRDCS). The potential to isolate the Reactor Protection System then represents a significant safety problem and is considered reportable under 10CFR50.55(e).

CORRECTIVE ACTION PLANNED United Engineers and Constructors has notified Westinghouse that the fourpenetrationswithRockbestosRSS-6-ll2cableareusgdforIEcircuits in an environment exceeding the recommended limit of 230 F and that these are to be replaced using IE qualified cable as required by penetra-tion specification 9779-055. UE&C has also notified Bechtel to write a nonconformance report and red tag the affected penetrations. Westinghouse also has been requested to determine if the Raychem cable, Raychem being the only other supplier of coaxial cable for penetrations, supplied for Unit 1 penetrations HE2, HH3, HIS, HK3 has a similar failure mode e as the Rockbestos RSS-6-112,

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CURRENT STATUS The four penetrations designated for Unit 4 have not been installed and currently are on hold. The evaluation of the Raychem cable has

yet to be completed.

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