ML20024B695

Part 21 Rept Re Deficiency in Bechtel Design of Ac & Dc Control Circuits for Facilities.Design Changes to Affected Motor Controller & Power Circuit Breaker Compartments Initiated.Also Reported Per 10CFR50.55(e) by Snupps

ML20024B695
Person / Time
Site:	Wolf Creek, Callaway, 05000000
Issue date:	06/30/1983
From:	Meyers B BECHTEL GROUP, INC.
To:	James Keppler, Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
REF-PT21-83-923-000 PT21-83-923, PT21-83-923-000, NUDOCS 8307110244
Download: ML20024B695 (5)

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I Bechtel Power Corporation Engineers - Constructors 15740 Shady Grove Road Gaithersburg, Maryland 20877 301 - 258-3000 June 30, 1983 J

Mr. James G. Keppler Director, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Mr. Karl Seyfrit Director, Region IV

( Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Suite 100, Parkway Central Plaza 611 Ryan Plaza Arlington, Texas 76012 File: 0490.4 SNUPPS Project, Bechtel Job No.10466 Report'of Design Deficiency Under 10 CFR Part 21 Gentlemen:

In accordance with the requirements of 10 CFR Part 21, this is to confirm reporting b Region IV Mr.(y Bechtel by telephone D. Honeycutt) to June Offices on the Region 27 and III (Mr.

June 24,H.1983, Westcott) respec-and tively.

The report concerns a deficiency in Bechtel's design of ac and de control l circuits for the Callaway (Region III) and Wolf Creek (Region IV) stations.

l The same deficiency was reported on June 23, 1983 by SNUFPS as a generic Significant Reportable Deficiency per 10 CFR 50.55(e) to Mr. H. Westcott (Region III)and Mr. J. Jaudon (Region IV).

Information concerning this deficiency has been furnished to other projects within this division, and to other Bechtel Powu Corporation divisions for review. It should be noted that th.is problem was previously reported to the NRC in October 1980 by Pennsylvania Power & Light for the Bechtel San Fran-l cisco Power Division Susquehanna Station project. Should it be determined l that this design deficiency is applicable to other Bechtle projects, this will be reported by the cognizant division directly to the cognizant Direc-tor (s) of the NRC Regional Office of Inspection and Enforcement, with a copy to you (if applicable).

JUL 5 1983 8307110244 830630 i

l PDR ADOCK 05000482 / [

S PDR /

Bechtel Power Corporation June 30, 1983 Mr. James G. Keppler Director, Region III Mr. Karl Seyfrit Director, Region IV Page 2 of 5 Following is specific information required by 10 CFR Part 21:

1. Name and address of the individual informing the Commission:

Mr. B. L. Meyers Bechtel Power Corporation 15740 Shady Grove Road Gaithersburg, Maryland 20877

2. Identification of the facilities which contain the defect:

Callaway Wolf Creek P.O. Box 198 P.O. Box 146

.ulton, Missouri 65251 Strawn, Kansas 66839

3. Identification of the firm constructing the facility that contains

'the defect:

Daniel International Corporation Greenville, South Carolina

4. Nature of the defect and the safety hazard which could be created by such defect:

Description of Control Circuits and Deficiency The SNUPPS 480 V MCCs utilize a separate control power transformer l

(CPT) for each individual motor starter control circuit. The power (VA) rating of each CPT ' varies with the rating of the controller to which it is applied, i.e., NEMA size 1, 2, 3, 4 or 5. The SNUPPS l- Class IE 4.16 kV switchgear and 480 volt load centers utilize a l 125 V de control power source from one of two class IE 125 V de station batteries.

I The SNUPPS ac control circuits utilize 14 AWG copper wire. Each CPT supplies its respective control load. The control load carried by each CPT is not identical for all CPTs, but generally consists of the associated motor controller and several types of auxiliary loads such as auxiliary relays and indicating lights. Together, the CPT rating, controller rating, control circuit conductor size, CPT auxiliary load and MCC voltage establish a maximum permissible i length of each individual ac control circuit cable.

Bechtel Power Corporation June 30, 1983 Mr. James G. Keppler Director, Region III Mr. Karl_Seyfrit Director, Region IV Page 3 of 5

4. Continued.

The SNUPPS dc control circuits also utilize 14 AWG copper wire.

Several indicating lights and auxiliary relays constitute a typical auxiliary load for each de control circi!it. Together, the switch-gear and load center control bus terminal voltage, circuit breaker closing current and minimum circuit breaker operating voltage establish a maximum permissible length of each de control circuit cable.

Investigation and quantification of the maximum permissible control circuit lengths revealed that selected Class IE ac and de control circuit lengths were excessive. Under conditions where the MCC bus voltage or station battery voltage was near its respective minimum design or end-of-duty cycle voltage, sufficient voltage to operate the controller or circuit breaker could not be guaranteed at the device terminals. The voltage drop across the control circuit that is produced when the controller or circuit breaker is energized, in combination with the parameters listed above, produces this situation.

The result of the excessive circuit lengths is, given the above voltage conditions, that certain safety-related equipment may not function (or start) during an accident.

5. The date on which the information of such a defect was obtained:

The failure of a non-IE starter on a 480 V transformer to function during startup testing at the Callaway site caused Bechtel Engineer-

ing to re-evaluate design assumptions and previously completed con-

trol circuit calculations for appropriate conservatism. Bechtel's l evaluation of the applicability under the provisions of 10 CFR 21 was concluded on June 23, 1983.

6. In the case of a basic component - the number and location of all such components:

! The deficiency is in the design of the control circuits rather than with basic components.

Bechtel Power Corporation June 30, 1983 Mr. James G. Keppler Director, Region III Mr. Karl Seyfrit Director, Region IV Page 4 of S

7. The corrective action which has been taken, the name of the organi-zation responsible for the action, and the length of time that has been, or will be taken to complete the action:

Bechtel Engineering has initiated appropriate design changes to the affected motor controller and power circuit breaker compartments.

Depending upon the specific circuit requirement, Field Rework Plans have been developed to provide for the installation of either larger control power transformers (ac control circuits) or for interposing auxiliary relays (ac and de control circuits). The larger trans-formers provide additional capacity to carry loads and to operate motor controllers with minimum permissible voltage. Where instal-lation of a larger transformer is not feasible, interposing relays will be installed to cause the control circuit to operate an auxil-iary relay instead of the controller..

Engineering will introduce a check in the design process to prevent future release of any control circuit until its engineered length is determined against established maximum control circuit length criteria.

8. Any advice related to the defect that has been, is being, or will be given to purchasers or licensees:

The SNUPPS organization, Union Electric and Kansas Gas & Electric have all been notified of this deficiency. As noted earlier, the details of this deficiency have also been furnished to other projects within this division and to other Bechtel Power Corporation divisions for coordina-tion with other licensees, as applicable.

Sincerely yours,

/

Bernard L. Meyers SNUPPS Project Manager l

JKJ/jmd cc: Mr. Victor Stello (3 copies)

Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Comission Washington, D.C. 20555

l Bechtel Power Corporation June 30.1983

~

Mr. James G. Keppler

'Directre, Region III Mr. Karl Seyfrit Director, Region IV Page 5 of 5 cc: Mr. N. A. Petrick (1 copy)

Executive Director, SNUPPS 5 Choke Cherry Road Rockville, Maryland 20850 Mr. S. J. Seiken (1 copy)

QA Manager,-SNUPPS 5 Choke Cherry Road Rockville, Maryland 20850 Mr. E. W. Creel (1 copy)

QA Manager Kansas Gas & Electric Company P. O. Box 208 Wichita, Kansas 67201 Mr. F. D. Field (1 copy)

QA Manager Union Electric Company P.O. Box 149 St. Louis, Missouri 63166