ML19269B927

Deficiency Rept 3 on HPCS Motor Control Center Wiring Discrepancies(Nrc HNP-A-013)

ML19269B927
Person / Time
Site:	Hartsville
Issue date:	12/07/1978
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19269B925	List: ML19269B924 ML19269B927
References
NUDOCS 7901190038
Download: ML19269B927 (4)

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• HARTSVILLE UUCLEAR PLANT UNITS Al, A2 B1, and B2 llIGli PRESSURE CORE SPRAY MOTOR CONTROL CENTER WIRING DISCREPANCIES REPORT NO. 3 (FINAL)

NCR liNP-A-013 on May 23, 1978, TVA notified NRC-0IE, Region II, Inspector John Rausch, of a potentially reportable condition regarding wiring deficiencies dis-covered in the unit Al high pressure core spray system (llPCS) motor control center (MCC). On June 23, 1978, TVA notified Mr. Rausch that similar wiring discrepancies had been found in llPCS MCC's for the other units and requested that the reportability of the deficiency be expanded to include all units. (llowever, subsequent investigation showed the MCC for unit A2 to have only nonsignificant discrepancies.)

TVA submitted a first interin report to NRC on June 22, 1978, and a second interim report on July 14, 1978. This is the final report on the subject NCR.

Description of Deficiency .

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During the course of conducting a general class for new employees in nondestructive wiring tes ting, the unit AlllPCS motor control center wiring terminations were checked for continuity against the as-built wiring diagram. A number of wiring discrepancies were noted as listed below (those termed significant are preceeded by a "*"):

Unit Al

1. Metering Relay Unit lA: FU-7 has wire labeled X-ll. Should be labeled X-1.

• 2.

IIPCS DG Immersion lleater Unit 2A: Terminal board terminals 5 and 6 have wires switched. .

3. Condensate Storage Tank Bypass Valve E22-F010 Unit 3D: Wire No. 6 to 42-C coil is number No. 3 at 42-C coll.

• 4. IIPCS DG Air Compressor Unit 3C: Wire No. 1 on relay 74 coil makes a loop on itself. It goes nowhere--does not tie coil to control trans-former.

• S. IIPCS Area 120-V Distribution Panel Unit 4A: The feeder service cable is loosely connected.

7901190038

• 6. Vertical Section No. 1: Strip heater screw is loose on terminal N.

• 7. Vertical Section No. 2: Bot'h strip heater screws are loose (terminals H and N).

• 8. Ground Bus (top horizontal wireway): Ground connection to control power transformer-for mett ing compartment is loose.

• 9.

Metering Relay Unit lA: Various loose terminal connections on terminal board.

Subsequently, the motor control centers for units A2, B1, and B2 were checked The MCC for unit A2 were found to have a few discrepancies of a nonsignifi-cant nature (mislabeled wires, etc.). Units B1 and B2 were found, however, to have the following significant discrepancies:

Unit B1

1. Metcring Relay Panel: The wire from TD-21 to M3 on the 95Z Agastat relay and the wire from TB-1 to M1 on the 95X Agastat relay are switched Unit B2

1. IIPCS DG Circ. Oil Pump Compartment: The pump breaker reset button is incorrectly labeled as a start button.

2. Suppression Pool MOV (MPL#E22-F012) Comp'artment: The feeder wires into the circuit breaker are switched such that the phasing sequence is 03, 01, 02, instead of 01, 02, 03, in accordance with vendor's drawings.

The motor control centers were procured by TVA as a part of the General Electric NSSS package and were fabricated by Powell Electric Manufacturing Company (hereinaf ter referred to as Powell) under subcontract with GE.

Cause of Deficiency The investigations by CE and TVA uncovered a number of individual causes for the listed discrepancies as follows (numbering corresponds to listings above by unit):

Unit Al

1. TVA interpreted the wiring labeling incorrectly (i.e., no dis-crepancy exists).

2. Powell has a mistake on the as-built drawing. The MCC is wired correctly.

3. Same as 2 above. -

4. GE said this wiring was correct when the unit was function-ally tested, lioweve r , the configuration

~ of the wire in the cabinet with this wire tied in a bundle of other wires by a wire wrap indicates that the discrepancy probably occurred at Powell after the test was performed.

5. through 9. Loose connections occurred during shipment.

Unit B1

1. These wires were wired incorrectly at Powell and were not found during functional testing because all relays are not checked.

Unit B2

1. Vendor error which the inspector missed.

2. Vendor error which the inspector missed. Phasing of each piece of equipment is not checked.

The overall cause for the deficiency is a combination of miswiring not caught during unit testing, one wire change evidently made af ter performance testing (but an isolated incident not found on other MCC's), and, in some cas failure of Powell to wire units strictly according to the approved wiring diagrams.

Safety-Implications TVA determined that this deficiency was repor' table because of the evidence of poor workmanship and the possibility that one or more of the wiring discrepancies might lead to the impairnent of the ability of an MCC and ultimately the llPCS system to perform its safety function. Subsequently, GE has analyzed each discrepancy independently and concluded that none of the listed discrepancies could prevent either MCC from performing its intended safety function. TVA agrees with the GE assessment on each indi-vidual discrepancy but maintains that quality workmanship is essential on production of items of this type.

Corrective Actions Corrective actions to clear up cl.c various discrepancies will be undertaken as follows:

Unit Al

1. No corrective action necessary.

2. Drawing will be revised by Powell to match the as-built configuration.

3. Same as 2 above.

4. TVA will be authorized by GE to wire this to the correct con-figuration.

5. t.hrough 9.

TVA will tighten these connections.

Unit B1

1. TVA will be authorized by CE to rewire the unit to the correct configuration.

Unit B2 ,

1. Vendor will provide the correct label for TVA installation.

2. TVA will be authorized by GE to change the feeder wires to correspond to the drawing.

TVA will take corrective actions as described above by March 1,1979, con-siderably before installation of the MCC's.

Means Taken to Prevent a Recurrence GE informed Powell in detail of this deficiency and they performed a QA audit of Powell (on Nov. 7 and 8, 1978) and will continue to audit Powell on a periodic basis. The Phipps Bend Nuclear Plant unit 2 MCC was at Powell 'uring the time of the audit and was wire checked by the GE QC inspet 'r, and only a couple of nonsignificant discrepancies were found. 1 u r the rmore , GE is now requiring Powell to do a complete wire check before performance. testing to ensure that the viring configuration matches the usibuilt wiring diagram.

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