GO2-83-160, Final Deficiency Rept 190 Re Excessive Cable Length Causing Voltage Drop.Initially Reported on 820511.Control Power Transformer Increased from 300 VA to 500 VA to Preclude Voltage Drop

Final Deficiency Rept 190 Re Excessive Cable Length Causing Voltage Drop.Initially Reported on 820511.Control Power Transformer Increased from 300 VA to 500 VA to Preclude Voltage Drop

ML20079N527
Person / Time
Site:	Columbia
Issue date:	02/22/1983
From:	Matlock R WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
10CFR-050.55E, 10CFR-50.55E, 190, GO2-83-160, NUDOCS 8303040253
Download: ML20079N527 (3)

Text

,

Docket Nos. 50-397

.- k 50.55(e) R:: port CEcp ime Washington Public Power Supply System 3

P.O. Box 968 3000GeorgeWashingtonWay Richland, Washington 99352f 372-5000 Docket No. 50-397 PJ p p EEGlC; y7 ,

February 22, 1983 G02-83-160 Mr. R. H. Engelken Regional Administrator U.S. Nuclear Regulatory Commission Region Y 1450 Maria Lane, Suite 210 Walnut Creek, California 94596

Subject:

NUCLEAR PROJECT N0. 2 10CFR50.55(e) REPORTABLE CONDITION #190 EXCESSIVE CABLE LENGTH

References:

1. Letter G02-82-0997, dated June 3, 1982, R. G. Matlock to R. H. Engelken, same subject.

2. Letter G02-82-718, dated August 27, 1982, R. G. Matlock to R. H. Engelken, same subject.

3. Letter G02-82-944, dated November 23, 1982, R.G. Matlock to R.H. Engelken, same subject.

In accordance with the provisions of 10CFR50.55(e), your office was inform-ed by telephone, of the subject reportable condition on May 11, 1982.

References 1, 2, and 3 above were interim reports on the same subject.

Attachment A provides the Project's final report on this subject.

If there are any questions concerning this matter, please contact Roger Johnson, WNP-2 Project QA Manager, at (509) 377-2501, extension 2712.

h

. Matlock l Program Director, WNP-2 LCF/kd cc: W.S. Chin, BPA - Site A. Forrest, Burns and Roe - HAPO N.D. Lewis, NRC J. Plunkett, NUS Corp.

A. Toth, NRC Resident Inspector - WNP-2 -

Document Control Desk, NRC WNP-2 Files - 917B 8303040253 830222 PDR ADOCK 05000397 0 PDR

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- 4 Attachment A j L WASHINGTON PUBLIC~ POWER SUPPLY SYSTEM NUCLEAR PROJECT N0. 2 DOCKET NO. 50-397 LICENSE NO. CPPR-93 EXCESSIVE VOLTAGE DROP DUE T0 EXCESSIVE CABLE LENGTH 10CFR50.55(e) CONDITION #190 FINAL REPORT Description of Defect or Noncompliance It was discovered that some of the circuits using size 4 starters have excessive control cable length in control circuits, thereby, limiting thc vult6ge available at startar tcrainals. Such voltage may be less

-than that required to pick up the starter coil.

Safety Implication HPCS-P-2 and HPCS-V-4 are required to attain safe shutdown of the plant under certain accident conditions. If they were tu be unavailable, it would negate some of the accident analysis in the FSAR.

Approach to Resolution All Class lE control circuits were investigated. It was discovered that

the control circuit wire length for HPCS-P-2 was too long to pick up the starter coil if MCC voltage was less than 90% of rated voltage.

Current Status i

The Architect Engineer, Burns and Roe, Inc., has performed a review of l

both the Burns and Roe and G.E. design to identify those instances where an excessive voltage drop can occur due to excessive cable length. It has been determined that the problem is relative to only MC-4A loads and is limited to HPCS-P-2 and HPCS-V-4. This was verified by Supply System Test and Startup via field tests. The concern of failure to pick up the starter coil is attributed to the following factors.

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1. High internal impedence and low VA rating of the control power trans-former (CPT).

2. Excessive cable length.

To resolve the problem for HPCS-P-2 and HPCS-V-4, the following alterna-tives were investigated:

1 i 1. Use control cable with #10 wire size (instead of #12) so that voltage drop in control circuit is reduced.

2. Increase CPT size so that voltage drop due to transformer impedence is low and longer control cable length can be used.

1

3. Use' interposing relay in control circuit so as to reduce the CPT burden

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, e-Attachment A Page Two ,

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I The Project has determined to implement option 2 to increase the control power transformer (CPT) from a 300 VA CPT to a 500 VA CPT. Project Engi-neering Directive (PED) 218-E-A320 has been issued to effect the required change for HPCS-P-2. PED 218-E-A815 has been issued to General Electric for their concurrence and issuance of interfacing documentation to effect the required change for HPCS-V-4.

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