View source for AECM-84-0393, Forwards Supplemental Info Re Standby Diesel Generator Combustion Air Intake & Exhaust Sys,Per 840802 Discussions, Superseding Info in (AECM-84/0389)

{{Adams
| number = ML20094B139
| issue date = 08/03/1984
| title = Forwards Supplemental Info Re Standby Diesel Generator Combustion Air Intake & Exhaust Sys,Per 840802 Discussions, Superseding Info in (AECM-84/0389)
| author name = Dale L
| author affiliation = MISSISSIPPI POWER &amp; LIGHT CO.
| addressee name = Denton H
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000416, 05000417
| license number = 
| contact person = 
| document report number = AECM-84-0393, AECM-84-393, NUDOCS 8408060249
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 3
}}

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MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi P. O. B OX 1640, J AC K S ON, MIS SIS SIP PI 3 9 2 05 August 3,1984 NUCLE AR LICENSING & $AFETY DEPARTMENT Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Mr. Harold R. Denton, Director

==Dear Mr. Denton:==

==SUBJECT:==
Grand Gulf Nuclear Station Units I and 2 Docket Nos. 50-416 & 50-417 License No. NPF-13 File: 0260/L-860.0 Supplemental Information -
Standby Diesel Generator Combustion Air intake and Exhaust System AECM-84/0393 Based on our discussions with your staff on August 2,1984, we are submitting the attached information on the Grand Gulf standby diesel generator combustion air intake and exhaust system. This information supersedes that submitted to you in our letter AECM-84/0389, dated August 2,1984.
If you have any further questions, please advise.
Sincerely,
                                                                        @CF
                                                                . F. Dale Director, Nuclear Licensing & Safety LFD/ sad Attachment cc:    (See Next Page) 8408060249 840803 PDR ADOCK 05000416 P                        PDR Member Middle South Utilities System

p AECM-84/0393
;                                    MIOl%:IPPI POWER & LIGHT COMPANY cc:  Mr. J. B. Richard (w/o)                                    -
Mr. R. B. McGehee (w/o)
Mr. N. S. Reynolds (w/o)
Mr. G. B. Taylor (w/o)
Mr. Richard C. DeYoung (w/a)
Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 2055S Mr. J. P. O'Reilly (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W., Suite 2900 Atlanto, GA 30323 O
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g Attachment to AECM-84/0393 Pagei SUPPLEMENTAL IWORMATION ON TK DIESEL GENERATOR COMBUSTION AIR INTAKE AND EXHAUST SYSTEM The combustion air intake and exhaust system for the standby diesel generators was designed as seismic Category I and Quality Group D. Augmented Quality Group D requirements were not imposed on this system. (Reference AECM-75/ l 1, dated February 14,1975 and AECM-82/0459, dated August 9,1982).
The piping specified for the system was seamless, schedule 20 (3/8" wall) ASTM A-53, Grade B or ASTM A-106, Grade B for the 24 inch diameter piping and welded, 3/8" wall, ASTM A-155, Grade C-55, Class 2 or ASTM A-134, Grade A-283C for the 42 inch diameter piping. This piping was butt welded by welders qualified to ASME Section IX. The piping was shop fabricated and assembled in the field. These welds were then visually inspected under shop fabrication conditions by Level ll inspectors qualified in accordance with SNT-TC-I A. The individuals qualified to this standard are competent to visually inspect the subject welds.
As described in AECM-83/0724, dated November 15, 1983, the piping wall thickness was more than adequate to meet the system design conditions and was substantially greater than that required to meet the actual service conditions.
Based on this substantial margin in the design of the piping for this system, the existing Quality Group D and seismic Category I classification is commensurate with the service conditions imposed on the system and adequately ensures the integrity of the system. The use of ASME Section IX qualified welders, the visual inspection performed on the welds, and the application of on operational quality assurance program for the piping provides additional assurance that the system is capable of performing its design function. The basic difference between the corrent design and installation and Quality Group C requirements is primarily the obsence of certain quality records. With the exception of the difference noted, the system as designed and installed provides an equivalent level of operational reliability and substantially the same level of safety as a system designed to ASME, Quality Group C requirements.
Therefore, based on the conservative system dasign as described above, actual system service conditions, the use of ASME Section IX qualified welders, visual inspection performed on the welds, and application of the operational quality assurance program for piping, then the imposition of seismic Category I and Quality Group D requirements on the standby diesel generator combustion air intake and exhaust system provides a level of assurance that the system is capable of performing its function commensurate with the level of assurance that would be provided by requiring the use of Quality Group C requirements.
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