ML20136C822

Forwards Request for Addl Info to Complete Resolution of Confirmatory Action 6 Re Insp of High Energy Piping.Concerns Include Potential for Inservice Degradation & Exam & Insp Methods

ML20136C822
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/26/1985
From:	Berkow H Office of Nuclear Reactor Regulation
To:	Walker R PUBLIC SERVICE CO. OF COLORADO
References
TAC-59787, NUDOCS 8601030434
Download: ML20136C822 (7)

Text

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'/ UNITED STATES

[ g, NUCLEAR REGULATORY COMMISSION t, a wAsHWGTON, D. C. 20655

,,,, December 26, 1985 Docket No. 50-267 Mr. R. F. Walker President

. Public Service Company of Colorado i Post Office Box 840

Denver, Colorado 80201

SUBJECT:

CONFIRMATORY ACTION 6 - INSPECTION OF HIGH ENERGY PIPING t

j We are reviewing your submittal dated December 10,1985(P-85460)

containing the confirmatory actions in support of our approval of Fort St. Vrain's operation at up to 35 percent of full power. Confirmatory i Action 6 states

" Submit a plan and perform inservice inspections on several critical areas of Fort St. Vrain's high energy piping to verify the:

j integrity of this piping, prior to returning the plant to operation." We have reviewed your submittal and relevant information in your updated FSAR.

i You have stated that the objective of your program is to verify the

! integrity of the Main Steam, Hot Reheat, Cold Heat, and Feedwater Systems and proposed the following actions to revolve ~this confirmatory action:

1) Perfonn volumetric examination of three (3) butt welds (8" pipe to 2

fitting, 8" pipe to elbow and 20". pipe to fitting),

l ~) 2 Perform volumetric examination of the base metal at the mid-point of

the 8" elbow and, 1 i

i 3) Use the inspection methods and analysss of the original plant piping construction code, ANSI B31.1.

In telephone discussions with the staff, subsequent to your submittal, your

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staff proposed four additional examinations of the Hot and Cold Reheat Systems. After due consideration of this additional proposal the staff concludes that Confirmatory Action 6 still remains to be satisfied for the following reasons: (1) There is the potential for inservice degradation, i

such as thermal fatigue, mechanical fatigue and creep-rupture phenomena in the materials of construction, and (2) The examinations you have proposed do not constitute a significantly representative sample of the number of

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material specifications, diameters and wall thicknesses of the piping systems accessible for inspection.

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. In addition to the two reasons stated above, you will likely encounter limitations to volumetric examination at the selected locations because of the geometric configuration of the fittings. Also, your proposed inspection  ;

, methods and acceptance criteria may.not be effective for the detection of inservice degradation, if present.

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, , December 26, 1985 In order to resolve these questions, the staff has prepared the enclosed request for~ additional information that defines the documentation needed to complete the resolution of Confirmatory Action 6.

Please advise the assigned Project Manager, Kenneth L. Heitner (301) 492-7364, of your schedule for.a response so that we may-pursue i resolution of this issue in a timely manner.

Sincerely, Original signed by Herbert N. Berkow, Director Standardization and Special

, Projects Directorate i

Division of PWR Licensing-B, NRR I

Enclosure:

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In order to resolve these questions, the staff has prepared the enclosed request for additional information that defines the documentation needed to complete the resolution of Confirmatory Action 6.

Please advise the assigned Project Manager, Kenneth L. Heitner (301) 492-7364, of your schedule for a response so that we may pursue resolution of this issue in a timely manner.

Sincerely, k

erbert N. Berkow, Director Standardization and Special Projects Directorate Division of PWR Licensing-B, NRR

Enclosure:

As stated cc-w/ enclosure:

e See next page 9

Mr. O. R. Lee Public Service Company of Colorado Fort St. Vrain cc:

C. K. Millen Albert J. Hazle, Director Senior Vice President Radiation Control Division Public Service Company 4210 East lith Avenue of Colorado Denver, Colorado 80220 P. O. Box 840 Denver, Colorado 80201 J. W. Gahm Nuclear Production Manager Mr. David Alberstein, 14/159A Public Service Company of Colorado GA Technologies, Inc. P. O. Box 368 P. O. Box 840 Platteville, Colorado 80651 Denver, Colorado 80201 J. K. Fuller, Vice President Public Service Company of Colorado P. O. Box 840 Denver, Colorado 80201 Senior Resident Inspector U.S. 9" clear Regulatory Commission a

P. 0. Box 640 Platteville, Colorado ~ 80651 Kelley, Stansfield & 0'Donnell Public Service Company Building Room 900 550 15th Street Denver, Colorado 80202 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Chairman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative Radiation Programs Environmental Protection Agency 1800 Lincoln Street Denver, Colorado 80651 l

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Fort St. Vrain (FSV)

Public Service Company of Colorado Docket-No. 50-267 Request for Additional Information

References:

1) Licensee's December 10, 1985 submittal, Attachment 1, Confirmator Action Item 6, Inservice Inspection (ISI) of high energy piping. y

2) FSV Updated FSAR.

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Background:

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Based on Reference 1, the licensee's inspection program is intended to verify the integrity of the Main Steam (MS), Hot Reheat (H. RT), Cold 1

Reheat-(C. RT), and Feedwater (FW) system prior to startup.

Staff Evaluation and Reouest for Information The licensee has not provided suf.ficient information in References 1 and 2 to reach a decision on confirmatory Action Item 6.

Soecif_ic infornation is reouired about the licensee's proposal and ISI parameters in the ioentified systems.

L Information about the licensee's proposal:

Ouestion 1.

Describe the criteria used to determine the critical areas selecteo for inservice inspection in the steam, feedwater, and cold and hot reheat lines. In particular, how are the effects of phenomena such as thermal and mechanical fatigue, creep-rupture,. corrosion and erosion considered in this selection?

' Question 2.

Provide the bases for the sample size selected considering that the sample size must be sufficient to detect inservice de examination methods must be effective to identify servicegradation present. inducedand theif flaws, Information about the high energy piping systems:

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The PowerFSAR has Figure Conversion System". 10.1-1 "Overall Flow Diagram, Secondary Coolant and For the Main Steam, Hot Reheat, Cold Reheat and 6

-- - s-.~ - , - - . . . , - . , -, ,-e v---. ,,m----~s--, --,----,---,-r,-,,a .- , . - -v. -g,,, , ,~,r-~

i Feedwater Systems, define the regions of these systems that are physically accessible for RT or UT if insulation were removed. The piping in the turbine crossover lines and the piping and vessels in the turbine by pass lines (desuperheaters and flash tank) should be included.

In the regions following that are physically accessible for inspection, provide the information:

A) Isometric drawings and tables showing the identification of circumferential and longitudinal welds, the diameter and wall thickness of the piping runs, and the material specification of the pipe and~ vessels (desuperheaters and flash tank).

B) General description of the . insulation, i.e., lagging or removable.

C) 1.ocation of RT or UT to be conducted.

D) General description of the weld crowns, i.e., "as welded" or ground.

The objective of the staff's question is to identify welds and base metal in accessible locations with similar material _ properties, configurations and operating conditions as in inaccessible locations.

Question 3.

Define the specific nondestructive methods that will be used on tne locations selected for inspection, i.e., radiography (RT), ultrasonic testing (UT), and/or surface examination and provide a copy of the criteria. Aprocedure examination including calibration standards and accentance summary of maintenanca record data should be provided where additional information supports the inspectior, proposal.

I Ouestion 4.

For locations that involve the examination of pipe fittings, provide tne technical basis that demonstrates that the examination procedures will detect inservice deoradation, i.e., cracks, corrosion and erosion, if present on tne fitting sice of the butt welds and the inside/outside radius of the elbow.

Question 5. Provide an engineering drawing for each of the locations selected showing dimensions and material specifications and,whether the welds are "as-welded" or prepared for.ISI.

Define the volume or surface of each location subject to ISI with the examination method superimposed, i.e.,

double-wall RT, angle-beam UT, straight-beam UT, PT, or MT.

Ouestion 6. In the MS welding of piping or co,mponents 4 inch or greater.H. RT, C. RT anc FW system A brief description should be provided of the mechanism of failure and the method of detection.

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Identify inch andany inservice failure of bolted connections with bolt diameters 1/2 greater.

4 The inspection of these systems 'should include any known degradation mechanism'in these systems.

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