ML19305A358

Final Rept on Deficient Air Filtering Units OVM-78A & B & OVM-94A & B.Vendor Notified Util of Improper Control Wiring. Wiring Will Be Replaced & Drawing Will Be Revised

ML19305A358
Person / Time
Site:	Midland
Issue date:	02/08/1979
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML19305A353	List: ML19305A352 ML19305A358
References
NUDOCS 7903130394
Download: ML19305A358 (2)

Text

\ i t e Attach =ent to Howe-78 79 khe ..

Bechtel Associates Professional Corporation

SUBJECT:

MCAR 27 (issued 12/28/78 Air Filtering Units (MR 7220-M-150)

FINAL REPORT -

DATE: February 8, 1979 PROJECT: Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Description of Discrepancy ,

Mine Safety Appliances (MSA), vendor of the air filtering units, has advised us by their ici.ter dated November 11, 1978, that they have found a discrepancy in the wiring installed from the local control panel mounted directly on the air filtering unit housing to the heaters of units OVM-78A and B and CVM-94A and E. MSA should have provided cini=um AWG sizes 10 and S wires to co= ply with the heater design requirements of NEC. Instead, size 12 wire was installed. MSA informed us f.t their telex dated December 19, 1978, that this discrepancy was the result of a lack of information on MSA's internal installation drawings. This type of document is not nor= ally subject to Bechtel review.

Safety Implications MSA stated in their telex dated Dece=ber 19, 1978, that if this discrepancy had not been detected, the heater could fall to function as a result of overloading of the wires. This failure could result in the charcoal absorber being subjected to high relative humidity air and thereby decreasing ,the absorption efficiency of the charcoal. This decrease in charcoal absorption ef ficiency of units OVM-8A and B (control room makeup air filter units) could result in the control room operator '

thyroid dose level to be exceeded as specified in 10 CFR 50, Appendix A,

. General Design Criteria 19, and as referenced in FSAR Subsection 9.4.1.1.

Failure cf the heaters in the fuel handling area exhaust air filter units OVM-94A and B is not considered reportable.

Corrective Action MSA proposes to correct the misapplication of wiring by replacing these wires with correct AWG sizes. The retrofit of these units will be done by Bechtel under MSA': supervision. NCR 1733 has been applied to the equipment at the site, and this will be used to fellow up and close this itca.

790313039i

Bechtel Associates Professional Corporation MCAR 27 FINAL REPORT February 8, 1979 Page 2 ISA informed us by telex dated January 26, 1979, that to prevent the above discrepancy from recurring on other projects, the applicable electrical schematie drawings will include the necessary wire information.

These drawings ' rill be subject to their (MSA's) standard QA review prior to release for f abricati m.

MSA also informed us by telex dated January 17, 1979, that the above discrepancy is limited only to the units identified.

Submitted by: f, e Approved by: sJuTds %

Concurrence by:  ;

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