ML19343B330
| ML19343B330 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/20/1980 |
| From: | Parr O Office of Nuclear Reactor Regulation |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8012230230 | |
| Download: ML19343B330 (5) | |
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Docket Nos:
50-369/370 o
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MEMORANDUM FOR:
B. J. Younoblood, Chief R
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Licensing Branch 1. 00L O
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Olan D. Parr, Chief Auxiliary Systems Branch. 'DSI SUSJECT:
MEETING SU$ NARY FOR VISIT TO MCGUIRE NUCLEAR STATION.
Attached are our minutes to the McGuire site visit of October 28 and t
- 29. 1980, for your issuance.
onginalsigned W -
Otan D. Pan Olan D. Parr, Chief Auxiliary Systems Branch Division of Systems Integration f
Attachment:
As stated cc:
D. Ross D. Eisenhut P. Check R. Tedesco R. Birkel l
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Docket No. 50-369/370 Applicant: Duke Power Company Facility:
McGuire Nuclear Station, Units 1 and 2 Summary of meeting held to discuss McGuire Auxiliary Feedwater System Reliability Evaluation
Background
The Reliability and Risk Assessment Branch (RRAB), utilizing the Sandia Laboratory personnel as consultants, are evaluating the Duke Power Company's reliability evaluation of the auxiliary feedwater system as prepared for the McGuire Nuclear Station. A visit was made to the McGuire site to provide RRAB and Sandia personnel as well as Auxiliary Systems Branch personnel, an opportunity to view the actual installation of the auxiliary feedwater system and to discuss RRAB and Sandia questions.
A list of meeting attendees is provided in Enclosure 1.
Ofscussion A meeting was held with the Duke Power Company on October 28 and 29,1980, to discuss the applicant's reliability evaluation of the auxiliary feedwater system for the McGuire Nuclear Station. The morning portion of the October 28, 1980 meeting took place at the McGuire site. Duke personnel provided a description of the auxiliary feedwater system design.
The McGuire system is unique in the manner in which the two train system is evaluated. One train consists of two sub-trains each consisting of a motor driven pump. Each sub-train will supply flow to two steam generators.
A second train utilizing a single turbine driven pump will supply flow to all four steam generators.
' Water to the suction of the pumps is supplied from several non-safety grade water sources; upper surge tanks, condenser hot well, condensate storage tanks and condensate hot well; and one safety grade water source, the nuclear service water.
In order to provide the minimum auxiliary feedwater (AFW) flow requirement (450 gpm) to the steam generators in the event of a main feed line break accident, the control valves in the AFW intake line to each steam generator are provided with mechanical stops. This arrangement will ensure that 450 gpm of feedwater can be pumped to the three intact SGs automatically as the control valve in the line to the fourth steam generator acts as an orifice which limits the loss of flow from the system.
This presentation was followed by a visit into the plant to view the actual installation.
The remaining portion of the meeting took place at the Duke Power headquarters office in Charlotte. The applicant and their NSSS vendor, Westinghouse, presented a detailed description of McGuire's AFW system reliability analysis report. Westinghouse personnel described the assumptions, data and the mechanical model used to evaluate the system reliability.
l As indicated in the reliability analysis report, the McGuire system falls below the reliability characterizations for many of the operating Westing-l house plants (as given in NUREG-0611), especially in a loss of main feed-water accident.
In an attempt to explain the McGuire system's low reliability, l
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the applicant suggested that it was caused by the inclusion of an additional consideration, i.e. rupture of main feedwater line, when loss of main feedwater accident was evaluated. For the ooerating Westinghouse plants some form of operator action is required in 10 minutes. For McGuire this time has been increased In order to obtain this time change, however, the control valves to 30 minutes.
were orificed as discussed above. Otherwise the McGuire system would have the same reliability as the other operating plants.
The applicant indicated that a formal response to the questions previously forwarded by the NRC, and modified during the two days of discussion, would be provided later.
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Auxiliary Feedwater Reliability NRC - E - Duke Meeting October 28, 1980 Bill Shopsky E
PRA Doug Wood W
PRA G. A. Copp Duke Steam Production Ilmar Raisep E
Licensing Ken Canady Duke Steam Production S. D. Alexander Duke Design M/N D..L. Camp Sandia Division 1222 Armand Lakner NRC,NRR,RRAB
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