ML20090L760

Responds to NRC 750827 Request That Analysis Be Performed to Confirm Adequacy of Relief Valve Line Restraints Inside Torus at Plant & Insp of Relief Valve Line Be Conducted. Insp Demonstrated That No Failures in Piping Occurred

ML20090L760
Person / Time
Site:	Monticello
Issue date:	10/17/1975
From:	Mayer L NORTHERN STATES POWER CO.
To:	Ziemann D Office of Nuclear Reactor Regulation
References
12187, NUDOCS 9102120616
Download: ML20090L760 (2)

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s MSP NORTHERN 5 TATE 5 POWER COMPANY M I N N E A PO L.l G. M I N N E S OT A ts S 40 9 October 17, 1975 D n tory' a

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d Mr Dennis L Ziemann, Chief Operating Reactors Branch #2 f

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U S Nuclear Regulatory Commission Washington, DC 20555 i)/

Dear Mr Ziemanu*

_ cTh MONTICELLO NUCLEAR GENERATING PLANT

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Docket No. 50-263 License No. DPR-22 M

Relief Valve Line Restraints Innide Torus Your letter dated August 27, 1975 requested that an analysis be perfomed to confirm the adequacy of relief valve line restraints inside the torus at the Monticello Nuclear Generating Plant. Your letter also requested that an inspection of the relief valve lines and their restraints inside the torus be conducted for indications of danage or degradation.

The inspection requested in your letter was completed during the Fall refueling outage. All relief valve lines and restraints were visually examined from the vent header penetration to the rams-head discharge. The inspection was accomplished using written procedures which listed the specific items to be in-spected. All U-bolts, piping, gusset plates, and 1-beams were examined for cracking or indications of abnormal movements. The inspection demonstrated that no failures in relief valve piping restraints have occurred at Monticello.

The engineering analysis is currently being perfomed, but the results wi'.

not be available for submittal until November 14, 1975.

Based on the results of relief valve piping restraint structural analyses performed whef'thegelief torus baffles were removed, we fully anticipate that the current; analys1V(ill, demonstrate sufficient structural strength in the restraints'.

s '. N M7 Yours very truly, 0

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IDM/LLT/ak cc: J G Keppler G Charnoff Minnesota Pollution Conttol Agency Attn: J W Ferman 9102120616 751017 12187

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PDR ADOCK 05000263 o

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NRC DIL.HIDUTION FOR PART 50 DOCKET h..TERI AL r

(if MPDRARY FORM)

CONTROL NO:

12187 FILE:

FROM:

Northern States Power Co.DATE OF DOC DATE REC'D LTR TWX RPT OTHER Minneapolis, Minn.

L.0. Mayer 10-17-75 10-?0-75 XXX 1

TO:

ORIG CC OTHER SENT NRC PDR UX SENT LOCAL PDR Mr. Dennis 1. Ziemann

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CLASS UNC L ASS PROPINFO INPUT NO CYS REC'D DOCKET NO:

XXX 1

50-763 DESCRIPTION:

ENCLOSURES:

Letter RL our letter of 8-27-75.

Letter furnishing additonal trifo. on Relief Valve Line Restraints Inside Isrus....

(1 Copy EnclosurekReceived)

PLANT NAME: Monticello FOR ACTION /lNFORMATION SAB 10-21 75 BUTLER (L)

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