ML20080P632
| ML20080P632 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 09/16/1983 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Sternberg D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML20080P636 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ANPP-27823-BSK, DER-82-68, NUDOCS 8310070286 | |
| Download: ML20080P632 (5) | |
Text
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September 16, 1983 ANPP-27823-BSK/RQT.
U. S. Nuclear Regulatory Commission Region V Creekside Oaks Office Park 1450 Maria Lane - Suite 210 Walnut Creek, CA 94596-5368 Attention: Mr. D. M. Sternberg, Chief Reactor Projects Branch 1
Subject:
Final Report - DER 82-68 A 50.55(e) Report Relating To Underground Cables to Startup Transformers May Not Carry Full-Load Current At Maximum Site Soil Temperature.
File: 83-019-026; D.4.33.2
Reference:
(A) Telephone Conversation between J. Eckhardt and J. Cook on November 26, 1981 (B) ANPP-22521, dated December 13, 1982 (Interin Report)
(C) ANPP-23025, dated February 16, 1983 (Time Extension)
(D) ANPP-2 3347, dated March 24, 1983 (Time Extension)
(E) ANPP-23470, dated April 12, 1983 (Time Extension)
(F) ANPP-23756, dated May 16, 1983 (Time Extension)
(G) ANPP 27465, dated July 29, 1983 (Time Extension)
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR 50. 55(e ).
Very truly yours,
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g CC d q LLL_. (N E. E. Van Brunt, Jr.
APS Vice President, Nuclear Projects Management ANPP Project Director EEVB/RQT:sn Attachment cc:
See Attached Page 2 0310070286 830916 PDR ADOCK 05000528 S
PDR j l
j' Mr. D. M. Sternberg DER 82-68 Page 2 cc:
Richard DeYoung, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 T. G. Woods, Jr.
G. C. Andognini J. A. Roedel D. B. Fa snacht A. C. Rogers B. S. Kaplan W. E. Ide J. Vorees J. R. Bynum D. D. Green /P. P. Klute A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher R. M. Grant D. R. Hawkinson L. E. Vorderbrueggen G. A. Fiorelli S. R. F ro s t J. Self D. Canady Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway - Suite 1500 Atlanta, Georgia 30339
p FINAL REPORT - DER 82-68 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNIT 1, 2 and 3 I.
CONDITION DESCRIFFION This report was initiated as a result of a review of the current carrying capability of underground cables between the Start-up Transf ormers and the 13.8 kv Intermediate Switchgear. This review indicated that some cables may not be adequately sized to meet design requirements under worst case site soil temperature and thermal resistivity conditions. The initial cable design was performed using industry standards to develop assumptions regarding site soil temperature and thermal resistivity.
The cables are required to be sized using the rated current corresponding to the secondary winding of the start-up transformer.
Consideration must be given to conductor temperature rise due to the heating ef fects of buried cables as well as the load requirements when cable size is determined.
Since definitive information on soil conditions was not available for use in the original calculation, concern exists over the possibility that these cables are not adequately sized.
II.
ANALYSIS OF SAFETY IMPLICATIONS Calculation 13-EC-MA-610 determined that the maximum full load current in start up mode is 355A. Further, a soil analysis has been performed by M&E Technology to evaluate the soil conditions. The results of the M&E Technology report indicate that the 355A continuous load could not result in exceeding the allowable cable temperature limit of 90*C for soil conditions of 30*C ambient earth temperature and thermal reaistivity value (RHO) of approximately 75 CM *C /W. The thermal resistivity of soil measured with 95%
compaction at the time of test was 59 CM *C/W.
The 355A value is i
based on a worst case duct-bank configuration with 5-inch spacing at c ro ss-over.
In the present initial start-up configuration, Unit 1 is not supplied via the worst case cross-over duck bank l
configuration. The current configuration of the duct bank supplying Unit 1 is staggered and will result in higher ampacity. Therefore, l
the ampacities given by the M&E Technology report are very conservative.
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Based on the above discussion, and with present configuration of the duct bank supplying the Unit 1 startup load, the installed cables supplying the Unit 1 start up loads are adequate. This condition is consequently evaluated as not reportable under the requirements of 10CFR50.55(e) since a safety significant condition does not exist.
I 1
e III. _ CORRECTIVE ACTION The system will be used as-is for the interim. Bechtel Engineering is reviewing the alternatives to improve the ampacity of the installed cable system so that it can carry the maximum out put of the secondary winding of the startup transformer in a worst case condition. Based on this study design change packages will be issued to implement these changes.
Calculation 13-EC-MA-610 has been updated and M&E Technology's final report has been retained in Bechtel's project records.
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interoffice Memorandum
[.';TS Hartman File No.
J1.1 ANPP To Subject Transformer Feeder - Capacity Date February 17, 1983 From F.
Y. Tajaddedi of Engineering At LAPD Ext.
2924 Copies to K. G. Kreutziger J. Kitchens The results of thd attached report show that cable ampacities are more than adequate for cables feeding the start-up transformers under conditions ofTstO't'ing the plant and running the LOCA loads.
There is a limitation if the start-up transformer is continuously er.ergized for more than 2 to 3 weeks.
Since this case is r.ot the basis of our design, there is adequate margin in cables to prcvide the required current to the loads.
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