ML20199B423

Interim Part 21 Rept Re Defects Discovered in Limitorque Auxiliary Feedwater Flow Control Valve Motor Lead Insulation.Initially Reported on 860506.Replacements Will Not Be Available Until After 1986 Refueling Outage

ML20199B423
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	06/06/1986
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
REF-PT21-86-217-000 PT21-86-217, PT21-86-217-000, TAC-42502, NUDOCS 8606170138
Download: ML20199B423 (3)

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June 6, 1986 Trojan Nuclear Plant Docket 50-344 License NPF-1 Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1415 Maria Lane, suite 210 Walnut Creek CA 94596-5368

Dear Sir:

TROJAN NUCLEAR PLANT Further Information Relative to 10 CFR 21 Defect Report In a letter dated May 6, 1986, PCE sent Region V a 10 CFR 21 Defect Report (No. 86-01) identifying defects discovered in the motor lead insulation for the auxiliary feedwater (AFW) flow control valves at Trojan. This letter provides further information relative to the actions taken to correct those defects.

As described in the subject Defect Report, the motor lead insulation for the AFW flow control valves has exhibited a brittle nature. Movement of the leads during maintenance could cause cracks in the brittle insulation.

The weakened insulation would then be subject to failure under the normal vibration and operating environment of the motor actuator.

l To correct this defect, suspect motors were sent to the motor operator vendor (Limitorque) for repair, and spare motors were o(dered. When Limitorque returned the repaired and spare motors, four of the motors were adequately repaired; however, the remaining motors had the insulation leads frayed or exhibited low insulation resistance readings. This late in the refueling outage, replacement motors cannot be shipped to Trojan before the Plant's scheduled startup.

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Pending receipt of replacement motors, four of the originally affected motors (ie, those motors not sent to Limitorque) have boon repaired by 0606170138 860606 gQ PDR ADOCK 05000344 S PDR 121 S W S$rren Steet. Ponand. Oreyn 97204

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Mr. John B. Martin June 6, 1986 Page 2 coating the existing leads with GE RTV-21 and enclosing them with silicone-coated fiberglass braid insulation (Varglas silicone rubber sleeving).

Both ends of the sleeving have also been sealed with GE RTV-21. These materials have been evaluated against the environmental qualification requirements for their location in the Main Steam Support structure. This evaluation has confirmed the qualification of the materials for their 7

application in accordance with the DOR Guidelines. PCE considers the valves operable per Technical Specification 1.6, and to satisfy the t provisions of Technical Specifications 3/4.7.1.2 and 6.13.

These motors were originally purchased in 1985 to the latest environmental qualification requirements (NUP,EG-0588, Category 1). Since separate effects testing has been used to qualify the silicone-coated fiberglass sleeve and RTV-21, the repaired motors can only be qualified to the DOR Guidelines. Paragraph (1) of 10 CFR 50.49 states, " Replacement equipment ,

must be qualified in accordance with the provisions of this section unless there are sound reasons to the contrary". Regulatory Guide 1.89 (Revi-sion 1), Section C.6, defines sound reasons to the contrary. Regulatory Position C.6.e allows the use of replacement equipment qualified in accordance with the DOR Guidelines if replacement equipment qualified in accordance with the provisions of 10 CFR 50.49 is not available to meet i installation and operation schedules. However, ir. such case, the replace-ment equipment may be used only until upgraded equipment can be obtained and an outage of sufficient duration is available for replacements. PGE i intends to install upgraded equipment as soon as it becomes available,  ;

consistent with the Plant's operating schedule.

In the subject 10 CFR 21 Defect Report, it was indicated that the brittle condition of the insulation may be a quality control problem with the subcontractor (H. K. Porter) that supplied the motors to Limitorque. The subsequent repair defects described above appear to be due to poor workman-ship by H. K. Porter and lack of quality control inspections by both H. K. Porter and Limitorque. In order to more completely evaluate and con-fica these deficiencies, PGE is planning to perform an evaluation and audit of Limitorque to verify the adequacy of their quality control practices in assuring the environmental qualification of these motors. No replacement motors will be accepted by PGE pending completion of an evaluation of the quality control processes used by Limitorque as they relate to these perceived problem areas. Discussions are currently underway with Limitorque to schedule this evaluation and a complete vendor audit. It is expected that an evaluation can occur within the month. However, schedule constraints at Limitorque do not permit a complete QA audit until sometime l

in August.

In summary, NUREG-0588 qualified replacement motors for the AFW flow con-trol valves will not be available until sometime after the 1986 refueling outage. The repaired motors are at least environmentally qualified to the I

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W W M COIT4MN1y Mr. John B. Martin June 6, 1986 Page 3 DOR Guidelines, and will be replaced with upgraded motors, once they are received and confirmed to be qualified to NUREG-0588 (Category 1) require-ments, and an outage of sufficient duration is available for work on the AFW System.

Sincerely, Bart D. Withers Vice President Nuclear c: Director, Inspection and Enforcement U.S. Nuclear Regulatory Connission Washington DC 20555 Mr. i.ynn Frank, Director State of Oregon '

Department of Energy

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