ML20210T585

Advises of Status of Insp & Replacement of All Unidentified Wire for Environmentally Qualified Limitorque Operators Outside of Containment,Per .Justification for Continued Operation of Unit 3 & Related Info Encl

ML20210T585
Person / Time
Site:	Oconee
Issue date:	09/19/1986
From:	Tucker H DUKE POWER CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8610090082
Download: ML20210T585 (8)

Text

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DUKE POWER GOMPANY P.O. box 33189 CHARLOTTE, N.C. 28242 HALB. TUCKER Tux.nenown vous emessemwr (yo4) 373 4531 woon.aan e m mion September 19, 1986 en cn ce r,

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Dr. J. Nelson Grace, Regional Administrator -

U. S. Nuclear Regulatory Commission **

Region II :3 101 Marietta Street, NW, Suite 2900 M Atlanta, Georgia 30323 RE: Oconee Nuclear Station, Units 2 and 3 Docket Nos. 50-270 and 50-287

Dear Dr. Grace:

By letter dated August 12, 1986, Duke Power Company (Duke) provided to NRC/ Region II a brief report regarding the possible existence of unidentified wiring in containment motor operated environmentally qualified valves at Oconee Nuclear Station and Duke's " Justification for Continued Operation for Units 2 and 3". The August 12, 1986 Duke letter also identified certain actions that Duke would take in regard to this situation. One of the actions identified within the letter concerned the inspection and the replacement of all unidentified wire for all outside containment environmentally qualified Limitorque Operators in Unit 3 by September 19, 1986.

The purpose of this letter is to advise NRC/negion II of the status of Duke's efforts in completing the above mentioned action. Please note that all other actions identified by the August 12, 1986 letter are not impacted.

During the process of inspecting and replacing unidentified wire in the Unit 3 environmentally qualified Limitorque Operators, Duke identified 5 valves that could not be cycled during power operations. Following modification (i.e., replacement of wires), the valve would be cycled as part of the post-modification testing function. The 5 valves in question are: 3HP-26; 2LP-17; 3LP-18; 3LPSW-6; and 2LPSW-15. The reason why these valves could not be cycled during power operations is provided by Attachment 1.

Duke has inspected these valves and identified all the wires within the operator.

Attachment 2 provides a list of wires that were identified and a evaluation of each wire type identified. Attachment 3 provides the inspection results of the 5 valves in question.

8610090082 860919 0 q DR ADOCK 0500 T

Dr. J. N;1 son Greca, Regi:nal Administrat:r September 19, 1986 Page Two f

For the 5 valve operators in question (3LP-17, 18; 2LPSW-6, -15; and 3HP-26), Duke will rewire them during the upcoming refueling outage for Unit 3 currently scheduled to begin in February 1, 1987. Attachment 4 provides the Justification for Continued Operation for Unit 3.

Very truly yours, AWA#

Hal B. Tucker

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PFG/25/slb Attachments xc: Dr. J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. C. Bryant NRC Resident Inspector Oconee Nuclear Station l

Attachment 1 Unit 3 Valves That Cannot be Cycled Valve No. Explanation for Inability to Cycle 3HP-26 This valve is the HPI to Reactor Inlet Valve. This valve cannot be cycled since opening the valve would result in flow through the "A" Emergency HPI header, and thus could result in overpressurization of the RCS. This valve cannot be isolated without isolating makeup flow to the RCS.

3LP-17 These valves are the LPI Line "A" and "B" Valves. These valves 3LP-18 cannot be cycled with the unit operating because of the possibility of overpressurizing the LPT System. In addition, Duke had previously committed to the NRC not to cycle these valves during power operation.

3LPSW-6 These valves are the LPSW to RC Pump motors. Bearing cooler supply 3LPSW-15 valves cannot be cycled with the RC Pumps running because closing the valve could result in damage to the RC Pumps.

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Attachment 2 Wire Type Identification and Evaluation Wire Types:

(1) ITT hook-up wire - Identified by markings on wire (2) Hypolon - Identified by lab analysis (3) PVC (TFF & TW) - Identified by markings on wire similarity (4) Rockbestos Firewall SIS - Identified by markings on wire (5) Houston wire & cable XLPE - Identified by markings on wire (6) Vulkene (XLPE) - Identified by markings on wire.

(7) Thick insulation field rung cable - Identified by markings and similarity to field run cable (8) High temperature braided wire - Identified by similarity to motor leads.

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l Eraluation:

1. ITT hookup wire insulation is a radiation - cross-linked extruded -

polyalkene with a radiation cross-linked extruded polyvinylidene fluoride jacket. Temperature rating of this wire is 150 C (302 F).

This wire was tested and qualified for outside containment applications under Wyle Test Report 44390-5.

Hypolon is a chlorosulfonated polyethylene insulation. Hypolon has 2.

been aged to a 40 year qualified life at 150 C (302 F) with no significant change in electrical properties (Reference Okonite Report No.110E). EPRI Report NP-2129 indicates a recommended servios limit of SX107 Rads. Hypolon is susceptible to synergistic effects of elevated temperatures and radiation.

3 Polyvinyl chloride (PVC), types TFF and TW is the original jmper wires supplied by Limitorque. Type TFF is a MC insulated single conductor fixture wire manufactured under UL standard 0 62.

Type TFF wire is rated for continuous duty at 60 0 C (140 0 F) and is required, under UL62, to withstand 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at 121 C (249 F) with out showing signs of any cracks on the surface or internally. Type W MC insulation is manufactured under 0UL Standard 1581. Type W wire is rated for continuous duty at 0 C (249 60 C 0(140 F) and is also required to withstand I hour at 121 F) without showing signs of any cracks on the surface or internally.

EPRI-NP-2129, " Radiation Effects on Organic Materials in Nucipe Plants" indicates WC cable insulation is affected af ter 5x10 LRads.

" Fundamentals of Nuclear Hardening of Electronic Equi; ment",7 . W.

Ricketts, indicates radiation resistance of MC to be 1.9x10 Rads.

Additional searches of reference documentation on N{ insulation also indicate a resistance to radiation above 5.0x10 Rads.

Additionally, Duke Power Company has tested and qualified a similar type MC insulation system under test report TR-032 (MOf-1354.00-0022-001) to the following parameters:

Peak Temperature: 380 F Peak Pressure: 29 3 PSIG Hmidity : 100%

Radiation: 8.26x107 Rads Qualified Life: 40 years & 1 year Post- Accident

4. Rockbestos Firewall SIS, both chemically and radiation cross-linked wire, is qualified for all postulated accident environments under Rockbestos reports #8504 and #8505, respectively.

The following wire types are acceptable for this application by similarity to the same type insulation material, which has been tested and qualified as reported in the evaluation section of the attachment:

3 PVC (TFF & TV)

5. Houston Wire and Cable XLPE

6. Vulkane (XLPE)

Hypolon, wire type #2, is acceptable for this application due to thermal testing at 302 F and a recommended service limit of 5x10 7 Rads as indicated by the evaluation section of this attachment. It should be noted that only synergistic effects, i.e. combination of elevated temperature and radiation exposur e, woduce significant degradation as indicated by reference documentation. Further assurance of the hypolon insulation to maintain its integrity is movided in that for this application no synergistic scenarios are postulated.

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Attachment 3 i

VALVEf INSPECTION RESULTS 3LPSW-6 White Wire (Limit Switch 5 to 4)

Red Wire (Limit Switch 1 to 5)

Black Wire (Limit Switch 2 to 6) (Appears to be Hypalon)

All long jumpers from Torque switch to Limit Switch were Red wires except for one Blue wire which appeared to be different in color only.

3LPSW-15 Red Wires (Torque Switch to Limit Switch)

White Wire (Limit Switch 5 to 4)

Black Wire (Limit Switch 2 to 6) (Appears to be Hypalon) 3LP-17 Black Wire (Thick insulation did not appear to be Hypalon)

White Wire Black Wire (Appears to be Hypalon) 3LP-18 White Wire White Wire

, White Wire i

3HP-26 This operator was inspected on September 19, 1986. It was found to contain jumpers fabricated from the field run cable.

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l Attachment 4 Justification for Continued Operation l

3LPSW-6: All jumper wires identified from the inspection have been evaluated and found to be acceptable (See Attachment 2) with the exception of one

" unidentifiable" blue wire. Although it is suspected that this wire is an acceptable type of PVC, visual inspection only does not provide sufficient information to confirm acceptability of this wire. However, 3LPSW-6 is located in the Penetration Room and is a containment isolation valve which is not required to function during a steam line break in the Penetration Room. The only required safety function of the valve is to close and remain closed during a LOCA. The only harsh environment is post-accident recirculation radiation which does not

, begin until approximately 30 minutes into the vent. Additionally, for long-term recovery, this valve can be accessed following a steam line break for repair or manual operation if required.

Operating procedures will be revised to de-energize 3LPSW-6 within 30 minutes of the containment isolation signal following a LOCA.

3LPSW-15, 3LP-17, and 3LP-18: All jumper wires identified from the inspection have been evaluated and found to be acceptable (See Attachment 2).

3HP-26: Subsequently inspected and found to contain wires identified in Attachment 2. All jumper wires have been evaluated and found to be

. acceptable for this application.

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