ML20091B557
| ML20091B557 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/31/1977 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Stello V Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9106070358 | |
| Download: ML20091B557 (4) | |
Text
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NSED NORTHERH STATES POWEM C0MPANY M 4 N N E A PO U S. M O N N E S OT A 99400 1
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C Mr Victor Stello Director
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Dear Mr Stello:
k MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50 263 License No. DPR 22 Pecdwater Nozzle Repair Program During the September 1977 Honticello refueling and maintenance outage, Northern States Power Company plans to engage in a feedwater nozzle repair program con-sisting of the following major activities a) Removal of existing feedwater spargers and thermal sleeves, making the four nozzles accessible for modification, b) Machining of the nozzle bore and safe ends to accournodate a new interim designed thermal sleeve and machining of the nozzle blend radius and bore to remove the stainless steel cladding, c) installing new feedwater spargers with new thermal sleeves into the machined nozzle. The new themal sleeves will be interference fit piston ring seal sleeves in place of the existing interference fit sleeves.
The above repair program will be performed in accordance with the ASME Code Section XI,1974 Edition, with Addenda up to and including the Wintor of 1976 Addenda.
Surface indications which might exist in the feedwater nozzles are being removed by machining off the cladding snd approximately one half inch of heat affected base metal underneath.
This repair will be done in accordance with Article IVB 4310 of Section XI.
The design analysis requirements are in compliance with the requirements of Article NB-3000 of ASME Code Section III,1974 Edition, with Addenda to and including the Winter 1976 Addenda.
Since renoval of some base metal is pi.anned, the adequacy of reinforcement is being recalculated according to the requirements of NB-3330, and specifically to the alternate rules of NB-3339.
Since the feedwater nozzle is slightly closer to the CRD and instrument 9106070350 770031 PDR ADOCK 05000263 P
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NOR 4ERN CTATEO POWER CC FANY Mr Victor Stello Page 2 Augt.s t 31, 1977 line nozzles than is allowed by h>3339.1, we propose to invoke the rules of Code case 1804. Attachment I shows that the nozzle spacing is well within the Itmits established by Code Case 1804.
Yours very truly, ho L 0 Maye r, PE Manager of Nuclear Support Services L(tihntV/deh cc J G Keppler G Charnoff MPCA Attnt J W Feman Attachment
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8/31/77 Letter from Mr L 0 Mayer (NSP) to Mr V Stello (USNRC) l ASME Code, Case 1804, for rainforced norstes which are rapaired by mechanical removal of material containing surface indications, states:
"The spacing, ts, between the edge of the opening being con-l sidered and the nearest edge of any other op is not less I'
than the smaller of 1.25 (d1 + d ) or 2.5 RT but in any 2
case not less than 1.0 (d1 + d ), where di nd d2 are the inside 2
diameters of the openings."
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1he proximity of the CRD return line and the instrtunent line nozzles to the nearest feedwater nozzle is as follows:
Edge to Edge Mininaan Code Allowabic 2
Norrie Nozzle Spacing. La_
Spacing. 1.25 (dt + d ).
2 CRD Return 36.89" 20.33" Inst rtunent 37.35" 18.91" l
l Tor both nozzles in question, the separation from the feedwater nozzle is well in excess of the ministan allowed by Code Case 1804 and is therefore acceptable.
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oATa Mr. Victor Stello ggp 08/31/77 Minneapolio, Minnesota 55401 L. O. May e r 0*Tj)No$[77 srte n ONoTomirto anoe iNevtsomu Nvusan or cceits ancalvto 3oniO4NAL IvNCLASSIPlIo
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(W sNctosuma cnierioN Furnishing information concerning Consints of info concerning nozzle Ftedwater Norzle Repair Program activities spacin2...
during the Sept. 1977 refueling and maintenanc e outage...Trans The Follwoin3,8
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