ML20101G447
| ML20101G447 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/12/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-31453-TDS, DER-84-76, NUDOCS 8412270510 | |
| Download: ML20101G447 (4) | |
Text
{{#Wiki_filter:s' ,$fE0 Arizona Nuclear Power Project sp; g ; / /ff 8 / p P.O. BOX $2034 o PHOENIX, ARIZONA 85072-2034 December 12, 1984C @,;,,. ANPP-31453-TDS/TRB U. S. Nuclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention: Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects
Subject:
Final Report - DER 84-76 A 50.55(e) Reportable Condition Relating To Diesel Generator Stator Temperatures. File: 84-019-026; D.4.33.2 Reference A) Telephone Conversation between D. Hollenbach and T. Bradish on October 3, 1984 B) ANPP-31032, dated November 2, 1984 (Interim Report) C) ANPP-31258, dated November 30, 1984 (Time Extension)
Dear Sir:
Attached is our final written report of the deficiency under referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e). Very truly yours, \\ Y,E N ce s s E. E. Van Brunt, Jr. APS Vice President Nuclear Production ANPP Project Director EEVB/TRB/nj Attachment cc: See Page Two O 0 fh z S
3- -- ;. m J L Mr. D.' F. Kirsch : p DER 84-76 l Page Two i r l - cc: Richard DeYoung, - Director j Office of, Inspection and Enforcement l-U. S. Nuclear Regulatory Commission ( Washington, D. C. .20555 T. G. Woods, Jr. D. B. Karner W. E. Ide D. B. Fasnacht A. C. Rogers L. A. Souza D. E. Fowler T. D. Shriver i C. N. Russo l B. S. Kaplan J. R. Bynum i J. M. Allen A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher H. D. Foster D. R. Hawkinson R. P. Zimmerman L. Clyde M. Matt T. J. Bloom D. N. Stover l J. D. Houchen J. E. Kirby D. Canady Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, GA 30339 i i l I J
_ _ - ~ _ _ - _ -. _ -- . lt ' ' FINAL REPORT - DER 84-76 DEFICIENCY EVALUATION 50.55(e) ' ARIZONA PUBLIC SERVICE COMPANY (APS) PVNGS UNITS 1, 2, 3 I. Description of Deficiency The diesel generator system is supplied by Cooper Energy Services - (CES). Parsons Peebles-Electric Products (PPEP) is the subcontractor i who manufactured the generator. The generator instruction manual (MM018-389-2,- Page 58-18, Section SB.2.3.1h. and j.) states that the diesel generator stator has maximum temperature limits of 135*C at ' rated (100%) load and'145'c at overload (110%) conditions for a maximum ambient temperature of 60*C.. Also, the generator windings - are insulated with Class F insulation which has a continuous maximum temperature rating of 155'C.(Reference 1). Operation above these limits will reduce the. qualified life of the generator. i NCR SM-4916 was issued to document the condition of~ potential overheating of the diesel generator. stator. This condition was discovered during startup testing of the Unit 1, train A diesel j generator. Per. the NCR, the generator was being run at 110% rated [ load with an ambient temperature of 41*C when the generator stator-l temperature was recorded to be 145'C. The generator load was then i reduced to 100% and the generator stator temperature was allowed to t stabilize. The stator temperature.was then recorded to be 1 approximately 138'c at an ambient temperature of-43*C. This i temperature data, when extrapolated to a 60*C' ambient temperature, yields a stator temperature of 164*C at 110%' load and 155'c at 110% { load. These stator temperatures, if reached..would exceed the U allowable. limits. Evaluation. l l . The maximum stator temperature limits were not exceeded, though at-higher ambient temperatures, the. potential exists to exceed these limits. CES has determined via air and generator stator temperature. surveys, that recycling of: the generator discharge air contributed to the excessive stator temperatures. l The diesel generator room ventilation system consists of a louvered j air supply opening in the ceiling at the south end of the diesel j generator building (one per train), and a ceiling mounted essential-exhaust fan (HDA-J01, HDB-J01) (one per train) on the north end of, f the building (Reference drawing 13-P-ZGC-703, Rev. 3). The generator unit has air supply openings in the side of the housing, and air discharge openings along the perimeter of the top of l the. generator unit. It is not known what the exact root cause of the ~ 4 - overheating' condition is, 'though 'it appears that a large percentage i of the discharge air flowstream from the' generator was being recycled-instead of exhausted. This has been verified by taking air i temperature surveys after removing the access plates on the generator I' to increase ' air flow, as indicated in NCR SM-4916. r c-Ir,,,-,,--, yv m -m --y,-- ,-+.w---------M,, .v--. -,, - - + t -r..w,. ey--,y,ew-r,--, ,--A-*w,,w r,,.-www.-wme, ,u~.vt+-e--== . ;} =iV 4 [ . Final Report DER 84-76 .Page Two i. CES has transmitted the PPEP calculation which calculates the - qualified life of the generator stator duetto extended operation at the higher than design temperatures.. Operation of the diesel. generator at.110% load conditions is limited to a maximum of 2 hours for testing purposes in any 24 hour period of operation. This calculation shows that'the qualified life of the diesel generator I unit will be degraded from a 40 year life to 36.8 years from operation at the higher. expected temperatures. Operation of the diesel generator is required once every 31 days for testing purposes (Reference Technical Specifications Section 4.8.1.1.2) and for 30 days continuous for post-accident conditions (Reference IEEE-3223). II. Analysis of Safety Implications j Had this deficiency gone uncorrected, it would not represent a significant safety condition as explained above. Therefore, this condition is evaluated as not reportable under 10CFR50.55(e) and 10CFR Part 21. j III. Corrective Action A modification has been made to the Unit 1 generator air supply i and exhaust openings to increase air flow to the unit. This modification, as detailed in FCR 85,419-M,, adds air deflectors around the exhaust side of the stator and adds =a deflector over the removed i access plates, which were removed to increse air flow, to prohibit debris from entering the generator. As documented by NCR SM-4916, another stator temperature survey was performed after addition of the air deflectors to the generator. The survey showed that the modification was successful in lowering stator temperatures to within j. the specified design'11mits. The modifications for Units 1, 2, and 3 ' (installed under Design ' Change Package 10M, 2SM,. 3CM-DG-044) have been evaluated for seismic loadings and accepted by PPEP. The modifications for Units 2 and 3 will be completed prior to issuance of an operating license. l' =. - -.}}