ML20009F746
| ML20009F746 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/10/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21- 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8107310497 | |
| Download: ML20009F746 (2) | |
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OFFICis)l. COPY 400 Chestnut Street Tower II July 10, 1981
- b-SQRD-50-328/81-43 d
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Mr. James P. O'Reilly, Director g
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Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission JUL 3 01981
- 3 Region II - Suite 3100
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Atlanta, Georgia 30303 b
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Dear Mr. O'Reilly:
SEQUOYAH NUCLEAR PLANT UNIT 2 - FOXBORO MCA TRANSMITTERS -
SQRD-50-328/81 FIRST IMIERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. Taylor on June 12, 1981 in accordance with 10 CFR 50.55(e) as NCR SQN EEB 8112.
Enclosed is our first interim report. We expect to submit our next report by August 25, 1981. We consider 10 CFR 21 applicable to this deficiency.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY t
'i L.M. Mills $ Manager Nuclear Regulation and Safety Enclosure ec:
Mr. Victor Stello, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 a.
8107310497 810710 PDR ADOCK 05000328 s
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ENCLOSURE
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SEQUOYAH NUCLEAR PLANT UNIT I FOXBORO MCA TRANSMITTERS SQRD-50-328/81-43 10 CFR 50.55(e)
FIRST INTERIM REPORT Description of Deficiency A letter from the Foxboro Company dated March 12, 1981 indicated that some Foxboro transmitters might have deficient components in the amplifier of the transmitter. The transmitters which might be I
affected are models E-11 and E-13 with suffix codes /MCA, /MCA/RRW, or
/MCA/RR and a 10 to 50 mA output.
The first issue involves the possible use of incorrect insulating sleeving on transistor and zener diode lead wires in the amplifier.
Radiation resistant sleeving consisting of a silicone coated glass fiber braid has been substituted by a teflon sleeving in some transmitters. Tests have shown that teflon will become brittle and deteriorate with a substantial integrated radiation dose. Foxboro testing has demonstrated that the teflon sleeving used in these devices will withstand an integrated dose of 10 megarads with no noticeable detericration. Tests of 200 megarads produce the brittle ccnditions which can result in the teflon flaking from'the wires.
The second issue involves the use of a specific vendor's capacitor, which is not hermetically sealed (although claimed to be so). As a result, the capacitor electrolyte can leak under adverse conditions, I
specifically heat and time. This phenomenon was observed in recent tests of.transnitters using these capacitors. The capacitor in questien is manufactured by Cornell-Duelbilier and can be specifically identified by a type number in the fcrm TX-65-XXXX as well as a monogran in a box followed by a date code, e.g.,
CDE 0874.
It is assigned Foxboro part No. N0141MF.
The two deficiencies described above aay have been caused by Foxboro's failure to inspect or speci,fy these components of the transmitter, and they represent a potential breakdown in the vendor's QA program.
An identical NCR is being handled for Watts Bar Nuclear Plant under report WBRD-50-390/81-54, WBRD-50-391/81-52 (NCR WBN EEB 8109).
Interim Progress TVA is inspecting all Foxboro model E-11 and E-13 type MCA trans51tters which are used in safety systems. Sleevir.g inspected thus far has been of the correct type. Any amplifier boards which are found to contain the deficient capacitors will be replaced st Sequoyah.
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