ML20101H570
| ML20101H570 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/14/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-31463-TDS, DER-84-103, NUDOCS 8412280284 | |
| Download: ML20101H570 (4) | |
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A tc:ayED ce; Arizona Nuclear Power Project a p P.O. BOX $2034
- PHOENIX, ARlZONA 85072-2034 December 14,1984!;il:J t pc ANPP-31463-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 Projects and Safety
Subject:
Final Report - DER 84-103
$ 59. "if.c} Rep rtabh Condit.ict. Zelating To Diesel Geuerator Roof Hatch.
File: 84-019-026; D.4.33.2
Reference:
A) Telephone Conversation between D. Hollenbach and T. Bradish on December 13, 1984.
Dear Sir:
Attached is our final written report of the Reportable Deficiency under 10CFR50.55(e) referenced above.
Very truly yours, RQ OLW E. E. Van Brunt, Jr.
APS Vice President Nuclear Production ANPP Project Director EEVB/TRB/pik Attachment ec: See Page Two h
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Mr. D. F. Kirsch DER 84-103 Page-Two ec:
Richard DeYoung,: Director Office of Inspection and Enforcement-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 C. N. Russo B. S. Kaplan J. R. Bynum J. M. Allen A. C. Gehr i
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 J. D. Houchen 4
J. E. Kirby D. Canady f
Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, GA 30339
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FINAL' REPORT - DER 84-103 DEFICIENCY EVALUATION 50.55(e)
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~ ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNITS 1, 2, 3
$I.
Description-of Deficiency Category I structures,' including the diesel generator building, must be~ designed to withstand the effects of high wind and toronado
- loads.
Contrary to this, a condition may exist that would allow the diesel generator building roof hatch covers to displace or lif t.under l-tornado conditions.
Evaluation Review of the Civil / Structural design calculations for the diesel generator building (Calculation #13-CC-ZG-035, Rev. 0) revealed the possibility of roof hatch cover movement under tornado conditions..
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- The movement would be caused by a net upward force on the i
unrestrained 2 concrete hatch covers resulting from wind pressure and compartmental depressurization. Since the concrete covers are quite heavy (approximately.11,000'1bs. each) the above consideration was omitted-from the original hatch cover design. An additional calculation (Calculation #13-CC-ZG-035, Rev.1) has confirmed the i
possibility of this condition existing.
i The designs of removable exterior components such as missile shield doors and hatch covers for other project Category I structures have been reviewed and no other similar problem has been encountered. For this reason this deficiency is considered to be an' isolated case.
The engineering evaluation, which does not consider compartmental
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j venting, concludes that wind pressure and compartmental i
depressurization loads exceed the weight of the concrete hatch.
covers. This indicates that under tornado conditions the ' hatch covers could be lifted and become displaced. Hatch cover movement
- f could expose the diesel generator exhaust silencer and essential l
exhaust fan to tornado generated missiles and/or cause the covers to i
fall on the same. Damage to this equipment, which is safety-related, could impair the function of the diesel generator, and therefore, be j_
detrimental to the safe operation and ' shutdown of the plant, i
A more precise analysis, that takes into consideration partial venting of the diesel generator building may yield lower uplift forces than the current evaluation. The reduced uplift loads may be low enough to be resisted by the weight of the concrete hatch coves, i
thereby eliminating the possibility of cover movement.' This type of.
additional analysis, however, will not be performed due to its overall complexity and the relative simplicity of hardware changes l
required to preclude hatch cover movement.
II.
Analysis of Safety Implications 4
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Based on the above the subject condition is considered reportable i-under the provisions of 10CFR50.55(e). The roof hatch covers are not basic components and therefore the condition has been evaluated as
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not reportable under the ; requirements of -10CFR Part 21.
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r if Final Report 1-DER 84-103 Page Two III.
Corrective Action In order to insure that the diesel generator roof hatch covers remain f-in place under tornado conditions, restraints have been designed to j.
resist possible net upward force (Calculation #13-CC-ZG-035, Rev.
2).
The restraint design will be implemented by DCP 10C-ZG-800, 2CC-ZG-800, and 3CC-ZG-800 prior to Mode 2 for each unit.
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