ML20202C015

Forwards Request for Relief from ASME Code Section XI for Reverse Purge Lines on All Feedwater Lines to Steam Generators for Listed Welds & on Nuclear Svc Water Sys Determined Impractical.W/One Oversize Drawing.Fee Paid

ML20202C015
Person / Time
Site:	Mcguire
Issue date:	06/27/1986
From:	Tucker H DUKE POWER CO.
To:	Harold Denton, Youngblood B Office of Nuclear Reactor Regulation
References
TAC-61884, NUDOCS 8607110028
Download: ML20202C015 (8)

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DUKE Powim GoxPm P.O. ISOX 33180 CIIAHl.OTTE, N.C. 28242 II AL 11. TUCKEH TE _EPHONE vna perssorwt (704) 073-4531 partramenourrnow June 27, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ATTENTION:n B.J. Youngblood, Director PWR Project Directorate #4 l

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Subject:

McGuire Nuclear Station, Unit 2 j Docket No. 50-370 i Requests for Relief from ASME Code Section XI Requirement Determined to be Impractical

Dear Mr. Denton:

Please find attached two separate requests for relief (pursuant to 10CFR 50.55a(g)(5)(iii)) from Hydrostatic Testing requirements of ASME Code Section l XI of the reverse purge lines on all four feedwater lines to the Unit 2 Steam Generators (Attachment 1), and for welds 2RN2F2713, 2RN2F2714, 2RN132-4, and 2RN132-5 on the Unit 2 Nuclear Service Water (RN) System (Attachment 2).

The Feedwater (CF) System piping modifications were deemed necessary to correct a weld size deficiency where 6" x 2" concentric reducers attach to the 2" piping. A copy of McGuire flow diagram MC-2591-1.1 with the affected areas highlighted is enclosed. These changes are in progress now during the current Unit 2 refueling outage (similar changes are not needed on Unit I since this situation does not exist on that unit as a result of different engineering practices being used during construction). Note that this area of the system falls into the same area as that for which exemptions from Hydrostatic testing have previously been granted (reference Mr. T.M. Novak's (NRC/0NRR) letters to Mr. H.B. Tucker (DPC) dated December 29, 1982 and May 9, 1983). The Nuclear Service Water modification is discussed in my letter of December 18, 1985 to Dr. J.N. Grace (NRC/ Region II), and is also shown in Figure 1. This RN Train B modification was completed during the current Unit 2 refueling outage and all examinations specified by the attached relief request have been done (note that hydrostatic testing was successfully accomplished for similar modifications performed on Unit 1 (RN Trains A and B) and Unit 2 RN Train A due to mechanical pipe plugs (reference Attachment 2 Section 3.B) holding for those tests).

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Mr. Harold R. Denton, Director June 27, 1986 Page 2 Pursuant to 10CFR 170.3(y), 170.12(c), and 170.21, Duke Power proposes that this exemption request constitutes a required approval for McGuire Unit 2 subject to fees based on the full cost of the review (to be calculated using the applicable professional staff rates shown in 10CRR 170.20) and must be accompanied by an application fee of $150, with the NRC to bill Duke Power at six-month intervals for all accumulated costs for the application or when review is completed, whichever is earlier. Accordingly, please find enclosed a check in the amount of $150.00.

Because of the extreme difficulties in performing a Hydrostatic test on these portions of the systems, and the return of the systems to operation in a timely schedule, it is requested that these reliefs receive immediate attention. Should there be any questions concerning this matter or if additional information is required, please advise.

Very truly yours,

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Hal B. Tucker PBN/18/jgm Attachments Enclosure l xc: (with attachments only)

Dr. J. Nelson Grace Regional Administrator U.S. hTC I 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Darl Hood, Project Manager Division of Licensing Office of Nuclear Reactor Regulation l U.S. Nuclear Regulatory Commission Washington, D.C. 20555 l Mr. W.T. Orders

( Senior Resident Inspector McGuire Nuclear Station

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Mr. Harold R. Denton, Director June 27, 1986 Page 3 bxc: (with attachments only)

R.L. Gill J.B. Day S.A. Gewehr J.G. Torre N.A. Rutherford S.O. Addison J.O. Barbour Al Batts A.V. Carr C.B. Cheezem D.N. Gabriel W.W. Gallman G.W. Grier S.D. Hart A.J. Hogge, Jr.

R.A. Johansen NNS R.D. Klein MNS T.L. McConnell J.J. McCool E.O. McCraw T.N. Pressley R.P. Ruth Sumeo Seo G.J. Underwood

D.E. Whitaker MC-801.01 MC-802.05 l

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ATTACitMENT 1 '

DUKE POWER COMPANY McGUIRE NUCLEAR STATION REQUEST FOR RELIEF FROM ASME CODE SECTION XI REQUIREMENT DETERMINED TO BE IMPRACTICAL (1) Component for which relief is requested:

A. Name and Number Piping on Unit 2 feedwater (CF) system is to be modified in order to prevent a possible 2" line rupture due to insufficient weld size where the concentric reducer attaches to the 2" piping.

B. Function The main feedwater system supplies water to the steam generators where it removes heat from the reactor coolant system.

C. ASME Section III Code Class Equivalent Class 2.

D. Valve Category N/A.

E. Materials and Welds Materials: 2" C.S. Pipe, SA-106, B; Schedule 80, .218 wall 2" C.S. 90* Socket Weld Elbow, SA-105/SA-234 WPB, 3000 #.

Welds: There are four (4) full penetration groove welds and five (5) 2-inch socket welds on four (4) seperate feedwater lines.

(2) ASME Code Section XI requirement that has been determined to be impractical:

ASME B & PV Code,Section XI, 1980 Edition through Winter of 1980 Addenda, Article IWA-4400, IWC-5000.

(3) Basis for requesting relief:

Performing a hydrostatic test on the feedwater piping would be impractical, extremely difficult, and very costly, due to the following reasons:

(a) Isolation and preparation of this system would result in considerable additional radiation exposure to personnel.

(b) Additional time required to gag safety relief valves.

(c) Additional time required to pin or block main steam constant support hangers.

(d) Potential damage due to static load on main steam system caused by water solid condition.

(e) Potential damage to Steam Generator tube bundle.

(f), Potential leakage through main steam isolation valves, feedwater isolation valves, and other valves in the system (inability to hold pressure).

(g) Potential damage to instrumentation, or considerable delay due to isolation / removal of instrumentation.

(h) Loss of Steam Generator hydro cycle.

In addition

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to these reasons, the alternate examinations as specified in (4) are equal to or better than the required testing per the code.

(4) Alternate Examination A. 100% penetrant test of all boundary welds plus an additional inservice leak test with system at operating pressure. Also, a hydro will be performed at the 10-year inspection interval per Section XI of the ASME Code.

(5) Implementation These examinations, with the exception of the Hydrostatic Test, will be conducted after the feedwater piping modification is complete and prior to the system being declared operable.

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• ATTACHMENT 2 i

DUKE POWER COMPANY McGUIRE NUCLEAR STATION REQUEST FOR RELIEF FROM ASME CODE SECTION XI REQUIREMENT DETERMINED TO BE IMPRACTICAL

1. Component for which relief is required:

A.Name and number Inside and outside welds on two 18" slip-on flanges on the McGuire Unit 2 Nuclear Service Water System (RN). Weld numbers are 2RN2F2713, 2RN2F2714, 2RN132-4, and 2RN132-5. (See Figure 1)

B. Function An 84" section of carbon steel piping was removed from the RN system per NSM MG-20636 Rev. 1. An 84" section of stainless steel piping with flanged connections replaced the carbon steel section. The two slip-on flanges referenced in section 'A' of this request connect the stainless piping to the old carbon piping. The new. stainless section contains the RN pump 2B flow element, and is located on the pump discharge header.

C.ASME III Code Class Equivalent. Class 3.

l D. Materials and Welds Weld 2RN132 Fillet weld on inside of east most flange. Joint thickness is .250".

Weld 2RN132 Fillet weld on outside of east most flange. Joint thickness is .525".

Weld 2RN2F2713 - Fillet weld on inside of west most flange. Joint thickness is .250".

Weld ZRN2F2714 - Fillet weld on outside of west most flange. Joint thickness is .525".

Flanges - 18" , 150# raised face, carbon steel, slip-on.

Pipe - 18" Std. wall SA106

2. ASME Code Section XI Requirement that has been determined to be impractical l

ASME B and PV code section XI, 1980 edition through winter 1980 addenda, article IWA-4400, IWD-5000. j l

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3. Basis for Requesting Relief Hydrostatic testing of welds referenced in Section A of this request would be impractical based on the following reasons:

A. Section of piping containing subject welds cannot be adequately isolated for hydrostatic testing. Isolation valves are large Butterfly valves ranging from 10" to 30" in sizes with a history of leakage.

B. Attempts at hydrostatic testing between a blind flange and a Thaxton high pressure mechanical pipe plug failed. Irregularities on the inside surface of the RN piping due to corrosion, would not allow the plug to seat properly.

C. Additional testing as specified in Section 4 are better than required by ASME Class 3 requirements.

4. Alternative Testing All welding was subject to M.T. examination. An inservice leak inspection was conducted per McGuire procedure MP/0/A/7650/76 at system pressure and temperature.

5. Implementation All examinations have been done.

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