ML20198G625

Forwards Request for Addl Info Re Augmented Inservice Insp of Fluid Sys Piping & Turbine Disk Integrity,Per PSAR Review

ML20198G625
Person / Time
Site:	Satsop
Issue date:	12/31/1974
From:	Pawlicki S US ATOMIC ENERGY COMMISSION (AEC)
To:	Oreilly P US ATOMIC ENERGY COMMISSION (AEC)
References
CON-WNP-1323 NUDOCS 8605290704
Download: ML20198G625 (9)

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4 DEC 31 1574 P. D. O'Reilly Light Water Reactors Branch 1-3 Directorate of Licensing YAS1!INGTON PUBLIC POWER SUPPLY SYSTEM, WFPSS NUCLEAR PROJECTS HO 3 AND 5 (CP), (DRAFT Q-2)

Plant Nane: WPPSS Nuclear Projects No. 3 and 5 (CP)

Suppliers: Combustion Engineering Docket !!os, and Date: 50-508/509, 8/2/74 Requested Completion Date: January 10, 1974 Task: Peeting Agenda Items (Draft Q-2)

!!cview Status: Information requested Inforr.ation submitted by the applicant in the PSAR through Amendment 5 has been reviewed by the Perforr.ance Fection of the Materials Engineering Eranch, Directorate of Licensing. Adequate responses to the enclosed request for additional information are required before we can complete our evaluation. The applicant has not responded to our earlier questions 12.1 (5.2.7) and 12.13 (10.2.3) as yet, The branch position is enclosed.

Original sig ied by S. S. Pavelichi S. S. Pawlicki, Chief Materials FngineerinE Brench Directorate of Licensing Ei:CLOSt?.E:

Materials Encineerine Branch

!!ecting Agenda Iter:s (Q-2) and DISTRIBUTION:

Branch Technical Position FrEn 6-2 L Rdg. File Subject File ec: F. S. Pawlicki, L MTEB File R. M. Custafson, L W. S. Hazelton, L M. Bolotsky, L V. S. Coel, L -

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NJG3!ENTED I:: SERVICE INSPECTION OF FLUID SYSTEM PIPING 1.- Protective racasurea, structures and guard pipes should not prevent the access required to conduct the inservice examinations specified in the AS:!E Boiler and Pressure Vessel Cede, Section X1, Division 1, "P.ules for Inspection and Testing of Conponents in Light-Water Cooled Plants." ,

2. For those portions of fluid systeam/1 piping between containment isolation valves, or, where no isolation valve is used inside cont.9.innent , between th'e first rigid pipe connection to the contain-ncnt penetration or the first pipe uhip restraint inside containnent and the outside isolation valve, the entent of inservice exaninations conpleted during each inspection interval (l"A-2400, ASM3 Code,Section XI) should provide 100 percent volunetric exanination of

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c irc'~bferential u and longitudinal pipe velds within the boundary of these portions of. piping.

3. For those portions of fluid systensA! piping enclosed in guard pipes, inspection ports should be provided in guard pipes to permit the required examination of circunferential pipe velds. Inspections ports should not be located in that portion of the guard pipe passing through the annulus of dual barrier containnent =tructures.

-1/Fluid Systens. High energy fluid systens that are subject to the postulatica of piping failures outside containment against which protection of essentini systens nnd components is needed.

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E BPJ.NCll TECl:::ICAL POSITIO:: - MTEB TUPSl!;E DISI: INTEGRITY

1. Materials Selection The applicant's selection of a disk or rotor material is acceptable if in accordance with the following:

The turbine dish or rotor should be cade from a material and by-a process that tends to minimize flaw occurrence and maximize fracture toughness proporties, such as a NiCrMoV alloy processed by vacuum melting and degassing. The caterial should be examined and tested to

. meet the following criteria: ,

a. Chemical analyses should be made for each forging. Phosphorus and sulfur each should not exceed 0.015 wt.% for low pressure disks and 0.02 ut.% for high pressure rotors.

b. The fracture appearance transition temperature (50% FATT) as obtained fron Charpy tests performed in accordance with specific-ation ASTM A-370 should be no highar than O'F for low pressure disks and 50*r for high pressure rotors. Nil-ductility transitien (NDT) temperature obtained in accordance with specification ASTM E-208 may be used in lieu of FATT. NDI temperatures should.

be no higher than -30 and 20*F, respectively.

c. The Charpy V-notch (C ) energy at the minitun operating temperature of each low pressure disk in the tangential direction should be

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at least 60 ft-lbs. The C, encrgy of high pressure rotor materials at minicum operating temperature should be at least 60 ft-lbs. A ninimun of three C specimens y

should be tested in accordance uith specification /.ST.! A-370.

2. Fracture Tou gness The low pressure turbine disk and high pressure rotor fracture tough-ness properties are acceptable if in compliance with the follouing criteria:

The ratio of the fracture toughness (K7 ) of the disk and rotor materials to the maximum tangential stress at speeds from normal to design overspeed should be at least two /Es., and the fracture tough-ness of the low pressure disk material should.be at least 150 ksi

/in at cdnimum operating temperature. Bore stress calculations

. should include components due to centrifugal loads, interference fit, and thermal gradients. Sufficient varoup time should be specified in the turbine operating instructions to assure that toughness will be adequate to prevent brittle fracture during startup. Fracture toughness properties can be obtained by any of the following methods:

a. Testing of the, actual material of the turbine disk to establish

-the K Ic valua at normal operating temperature,

b. Testing of the actual material of the turbine disk with an instrumented Charpy machine and a fatigue procracked specimen to -

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e cstablish the K 7 (dynamic) value at nornal operating temperature.

If this nothod is used, K y (dynamic) shall be used in lieu of Ky (static) in eccting the toughnass criteria above,

c. Estimating of K y values at various temperatures from conventional Charpy and tensile data on the disk material using methods presented by J. A. Ecgley and U. A. Lonsdon in Westinghouse Scientific Paper 71-lE7-MSLRF-P1 (Ref. 5). This method of obtaining K g chould be used only on materials which exhibit a well-defined Charpy energy and fracture appearance transition curve and are strain-rate insensitive. The test data and the calculated toughness curve should be submitted to the staff for review. .

d. Esticating " lower bound" values of K y at various temperatures using the equivalent energy concept of T. J. Uitt and T. R. Mager, ORNL-T:t-3894 (Ref. 6). Load-displacement data from the compact tension specir. ens and the calculated toughness data should be submitted to the staff for review. .

3. Hinh Terperature Properties The stress-rupture properties of the high pressure rotor material are acceptable if they provide sufficient assurance of rotor integrity for the lifetina of the turbine. The applicant can demonstrate compliance by submitting stress-rupture data of an equivalent material with similar properties to the staff for evaluation.

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4. Precorvice Inepection The applicant's preservice inspection progran is acceptable if in compliance uith the folleting criteria:

a.. Disk forgings should be rough machined with minicum stock allow-ance prior to heat treatment.

b. Each finishad' disk should be subjected to 100% volunetric (ultrasonic), surface, and visual examinations using procedures and acceptance criteria equivalent to those specified for Class 1 components in the ASME Eoilcr and Pressure Vessel Code, Sections III and V.

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c. Finish reachined bores, keyways, and drilled holcs should be subjected to magnetic particle or liquid penetrant examination.

No flaw indication in keyway or hole regions is allowable.

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d. Each fully bladed turbine rotor assecbly should be spin tested at the maximun speed anticipated'during a turbine trip following loss of full load.

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5. Turbine Desien

. The applicant's design is acceptable if in acompliance uith the l

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The turbine assembly should be designed to withstand normal conditions, anticipated transients, and accidents resulting in a turbine trip E

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without loss of structural integrity. The design of the turbine assenbly should nact the following criteria:

a. The design overspeed of the turbine should be 130% of rated speed or 5% above the highest anticipated speed resulting from a loss of load, whichever is greater. The basic for the assumed design overspeed should be submitted to the staff for revieu.

b. The tangential stress in low pressure disks or high pressure rotors at design overspeed due to centrifugal forces, interference

. fit, and thernal gradients should not exceed 0.75 of the nininum specified yic1d strength of the caterial.

c. The turbine shaft bearings should be abic to withstand any

. combination of the normal operating loads, anticipated transients,

-an'd accidents resulting in turbine trip.

d. The turbine should be designed so that there are no critical' frequencies betecen zero and design speed. If such critical speeds exist, assurance should be provided that they are not within 20% of normal operating speed and that the turbine vill not dwell at them.

6. Inservice Insnection The applicant's inservice inspection program is acceptable if in compliance with the following criteria:

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The i'nservice inspection progran for'the stecu turbine asceably and for_ valves associated uith the overspeed prottetion cycten should provide assurance that dich flaws that night. lend to brittIc failurc of a disk at speeds up to design speed vill be detected and that ivalves important'to the overspeed protection system will be cperable when needed so the probability of disk rupture at destructive overspeed'will be reduced.

The' inservice inspection progran for the turbine assenbly should-include the following:

a. Disassembly of the turbine at approxinately 10-year intervals, during' plant shutdcun coinciding with the inservice inspaction schedule as required by ASME Boiler and Pressure Vescel Code,-

l Section X1, and conplete inspection of all normally inaccessible parts, such as couplings, coupl'ing bolts, turbino shaf ts, . low pressure turbine blades, low pressure disks, and high* pressure rotors. This inspection should consist of visual, rurfccc, and volumetric examinations,-as recuired.

The applicant should keep abreast of technological advances in:

volumetric examination techniques so that uhen improved cethods for inspection of turbine disks are developed they can be incorporated into the inservice inspec' tion program.

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b. Conduct an in-pince visuni cranination of the turbine assembly at accessibic locations during refueling shutdo.:ns at intervals not c:xceding two years.

The inservice inspection of coin steam and reheat valves should include'the following:

Dismantic at Icast one main steam stop valve, one main steam

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control valve, ona reheat stop valve, and one reheat intercept valve, at approxinately 3-1/3 year intervals during refueling or nointenance shutdo ms coinciding with the inservice inspection schedule required by ASME Code Section XI, and conduct a visual

. and surface examination of v11ve teats, disks, and stens. If unaccc table flaus or exessive corrosion ,a.re found in a valve, s all valves of its type shall be inspected. Valve bushings should be inspected c,d cleaned, and bore diameter should be check'ed for proper cicarrnce.

d. Main stcam stop and control and reheat stop and intercept valves should be exercised at least once a ucek by closing each valve and observing by the valve position indicator that it noves smoothly to a fully closed position. At least once a nonth this observation should be cade by actually watching the valve motion.

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