IR 05000334/1989024

Advises That Requesting Withdrawal of Violation Noted in Insp Rept 50-334/89-24 Inconclusive.Util Actual Measurements Demonstrate Wide Variation on Specified Angle Indicating Inaccuracies in Physical Measurement Technique

ML20055F578
Person / Time
Site:	Beaver Valley
Issue date:	07/02/1990
From:	Hodges M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Sieber J DUQUESNE LIGHT CO.
References
NUDOCS 9007180059
Download: ML20055F578 (2)

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JUL 0 2 H10

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Docket No. 50-334

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Duquesne Light Company ATTN: Mr. J. D. Sieber Vice President

, Nuclear Group J Post Office Box 4

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Shippingport, Pennsylvania 15077 r Gentlemen:

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jg Subject: Inspection No. 50-334/89-24 b This is in response to your letters, dat.ed February 23 1990, of the same subject. We have reviewed your submittal and find insufficient basis for withdrawing the violation because the iniormation supplied is inconclusiv .6

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However, we note that ultrisonic measurement of the counterbore angle is an

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indirect method and subject to some variance out clearly is capable of distinguishing between 18 degrees and 45 degrees. This is demonstrated in your mockup test data.

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The mockup test data contain anomalies that require f urther evaluation. First,

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the counterbore angles for the tests were machined at 18 and 45 degrees. Your 6 actual measurements demonstrate a wide variation on the specified angle

' indicating inaccuracies in the physical measurement technique or poor control

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of the machining process. Both of these conditions are the center of our concern and the reason for initially writing the violation. The safety significance of this issue is the possible contribution of this acute angle to the stresses in

the counterbore area which is closely related to the past failures you have experienced in the feedwater system p. pin During our telephone discussion of this matter on June 12, 1990, you stated

& that you have developed an improved technique for measuring piping counterbores ultrasonically. We suggest that this improved technique be qualified and used at the next reasonably convenient outage to snoko more precise measurements to aid in the resolution of this mctte Therefore, we will hold this matter open and reserve our final decision to

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withdraw the violation pending furthar i:iformation developed by you. Thank you for your cooperation in this matte b-

Sincerely, Origind SHned By:

Mervin W. tiodges

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Marvin w. Hodges, Director 1, ivision of Reactur Safety L-

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0FFICIAL RECORD C0pY R50-334/89-24 - 0001. sor5; ,00 ng 06/29/90

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PDR ADOCK owoom h Poc 2.E ol F*l ($ m

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_, JUL 0 2-1990 Duquesne Light Company 2 cc w/ enc 1:

. J J..Carey, Executive Vice President, Operations ._

- 'J . O. Crockett, General Manager, Corporate Nuclear Services W. S. Lacey, General Manager, Nuclear Operations N. R'..Tonet, Manager, Nuclear Engineering T. P. Noonan, General Manager, Nuclear Operations S. C..Fenner, QA Manager K._D. Grada, Manager, Nuclear Safety H. R. Caldwell, General Superintendent, Nuclear. Operations Public Document Room (PDR)

Local Public Document Roem (LPDR)

Nuclear Safety.Information. Center (NSIC)

NRC Resident Inspector Commonwealth of Pennsylvants bec w/ enc 1:

Region I Docket _ Room (with concurrences)

Management. Assistant, DRMA (w/o enc 1)

R. Bellamy,.DRSS-C.-Cowgill, DRP~

M.-Conner, SALP Reports Only K. Abraham, PA0 (20) SALP Report and (2) All Inspection-Reports-J. Caldwell, E00 P. Tam,'NRR

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I RI:DDS fStrosnider 6/33/90:

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RI:DRS Durr Hodges-6/f//90 /A/90 0FFICIAL RECORD COPY R50-334/89-24 - 0002. /28/90

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- vce Preeseent kamer Group Htti 393-5255 l/ '

February 23, 1990 (-  !

F U. S. Nuclear Regulatory Commission t x, Attn l

• Document Control Desk:

Washington, DC 20555 Reference: Beaver Valley Power Station,. Unit No. 1 Docket No. 50-334, License No. DPR-66 Inspection Report 50-334/89-24

Gentlemen *

In response to NRC correspondence'dateu January 23, 1990 and

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in- accordance with 10 CFR 2.201, the-attached reply addresses the-Notice of Violation included with the referenced inspection  ;

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repor Note that .we have performed a- detailed review of the

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circumstances ; surrounding the alleged violation.- Based on this-evaluation, included as part of our reply, we respectfully request that this' violation be withdraw '

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, If there are any questions concerning this response, please l _ contact my offic . ,

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.Very truly yours,

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. D. Sieber  :

Vice President

Nuclear Group  !

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Attachment cc: Mr. J. Beall, Sr. Resident Inspector Mr. W.r. Russell, NRC Region I Administrator Mr. Jacque P. Durr, Chief, Engineering Branch

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Division of Reactor Safety, Region I '

p" Mr. P. Tam, Sr. Project Manager Mr. R. Saunders (VEPCO)

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DUQUESNE LIGHT l COMPANY

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Nuclear Group Beaver Valley Power Station-Unit No. 1 Reelv to Notice of Violation Inspection Report 50-334/89-24 Letter Dated January 23,- 1990

- yIOLATION (Severity Level IV, Supplement I)_

.Descriotion of Violation (50-334/89-24-01)

The- Beaver. Valley Power Station Unit 1 Technical Specifications, Section 6.8.1, requires 'that written procedures be established, implemented and maintained in accordance with Section 9C, Repairs, of Regulator Guide 1.33, Revision 2 dated February 197 Accordingly, Ethe licensee developed procedural' drawing No. PIPS MO 6.1 ' . Detail- C, which specified a counterbore taper of 18' maximum

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for the steam generator feedwater nozzle to elbow weld.-

Contrary to- the above, as of October-19, 1989, the ultrasonic

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thickness profile for the- elbow _to steam generator nozzle-weld indicated that the counterbore~ taper was greator than 18' for approximately 30% of the weld lengt Discussion of Violation Duquesne ~ Light Company does not agree that the information stated above constitutes a vii.'atio We have-reviewed the details of the elbow end preparation, welding

.and-Ei nspection. Additionally, an elbow to nozzle weld mock-up.was produced 'to determine the accuracy technique for internal diameter (ID) contouring.on of the ultrasoni a shorttest-(UT)

radius elbo Our evaluation included a review of the following:

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Counterbore machining and preparation of the elbow

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Wald data sheets / quality control inspections

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-Radiography 1 film density surveys

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Ultrasonic contouring of the elbow mock-up Details of our activity review, the mock-up testing, and our

, results and conclusions-are included in Attachment As a result of our evaluation, we have concluded that:

1)' UT profiling using thickness measurements is capable of

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determining the general ID contou ~lHowever',; due ntopth inherentmolimitations?yofJ1they!UT: method,'1 f the;"'abilityz itol accuratelpildetermineithmicounterborectransition1 angle:fromithe UT_ profile 21s"notipossibl's swith any' degree 7of' confidenc J l

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Ranly t'a Notice of Violation.;

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'T-Inspection Report 50-334/89-24

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' Letter. Dated January 23, 1990

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.2). The- counterbore' transition angle is correct and uniform aroun ce ' thel full- circumference < of the ID. There is no evidence't indicate a' deviation from the engineering specifications.-

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Therefore,- we ask'that you review the details of our evaluation as presented ~ in Attachment- I and,' _ based on' this information,.we

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respectfully request.that this violation be withdrawn.'

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ATTACHMENT I DUQUESNE LIGHT COMPANY Nuclear Group Corporate Nuclear Sers ices Unit Nuclear Engineering Department

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NRC Inspection Reoort 50-334/89-24 The results of the routine NRC safety inspection conducted by

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M Karch on November 13 - 16, 1989 focused on an ultrasonic report, WP-89-185, produced by the ISI Department during final inspection of the elbow-to-nozzle weld in line 16WFPD-22-60 at the steam generator.

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with subsequent checks of the thickness measurements

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That report,

. by DLCo and NRC personnel, is the basis for the notice of

- violation, received January 28, 1990, which states " ...the ultrasonic thickness profile for the elbow to steam generator

nozzle weld indicated that the counterbore taper was greater than 18' for approximately 30% of the weld length."

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The details of that elbow end preparation, welding, and inspection, were reviewed

_ and the following information is pertinen Activity Review The elbow replacement was performed on MWR N in accordance with Duquesne Light C Plant Installation Process

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Standard M06.1 " Category 1 Piping Installation." The applicable end preparation configuration is Detail C of Figure 5.1 which

"" specifies m,av maximum ntransition a angle- of < c18 %from the < machined *

counterbore th"the as-fofged fitting internal diameter (ID).

The machining of the 16", short radius 90* schedule 80 elbow was

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done using a WACHS end prep lathe.

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Qualityd control'Linspection lwas vrequired9and/was recorded (on;the

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WeldliDataJSheet' , t The records show a hold point for "end

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prepafation/ wall thickness", which is attribute W-403.of I.P. N W-04P Re O, " ANSI B31.1 Pipe / Tubing Welding". nThe"verificationbd

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. included,7bevely angle,. land 4 thickness, .counterhorew depth,- andn9 counterbois,, transition janglexandsw'a111 thickness @ TheScounterbore

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transiti'onU abglet kas1*physicallpfmeasured Wu'singia protractor,!at

'severaly pointa naround Mthe.circuaterence.ofithe<ID at the, time =1of, jerificationit The end preps were madnetic particle inspected prior to welding and radiography was done at the root pass completion and as a final inspectio These process and 1 spection records were reviewed for any discrepancies which would explain the contours obtained by the ultrasonic thickness measurement Concurrently, an elbow to nozzle weld mock-up was produced to determine the accuracy of the ultrasonic testing (UT) technique for ID contouring on a short radius elbow.

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Attschm:nt I NRC_ Inspection Report 50-334/89-24-Page 2 Results The' use- of a pipe end prep lathe to machine.the counterbore contour would result in a. uniform transition angle for.360' of the circumferenc A steeper' angle for 30% of the circumference would requiren that angle to be machined the e- 're circumference and ths-remaining '70% to be hand worke The ent.ca prep contour was done using the end prep lathe with minor hand working for blending of

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rough edge o The . Weld Data Sheet contains the record of the- inspection-attributes for the end. pr4paration/ wall thickness which were signed off by Construction Welding and Quality . Contro No

. abnormalities or deviations were note During the exit interview, it was- called to the attention of the NRC inspector

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.that the transition angle verification was- an; actual physical,

. measuremen The Holdpoint Checklist, which is an attachment.to

'the Weld Data Sheet, provides another sequence of signoffs and also . includes the end prep signof The. Construction Weld-

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Engineer, at the time of verification, made a supplementary note on the checklist detailing; visible machining score marks on the machined transition at the 6:03 to 7:30 position, 1 1/,4 inches from- the prep edge. This corresponds to an area adjacent to the datum 2 position- where the questionable ultrasonic contour was take The radiography films for the completed weld were examined for sharp -density . changes indicating a steep transition angle. There was nothing visually apparen ,

Film density surveys were taken

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fromL the centerline of the weld.to the edge of the film at the datums 0 and- 2 (Extrados and Intrados, respectively) on each of two films covering _these location inches off' the weld centerlines. The; density change _due to the The surveys extended'to l'1/2 transition angle is expected in the area 1/2" to 1 1/8 inches off the centerlin The density survey readings, shown in Figure 1, were as expected for a properly machined contou The r"e u'ltrasonic Esame contouring of the elbow mock-up was performed using equipment and technique as that used during the

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.le-to-elbow inspectio The mock-up consisted of two tr.r.sition angles,. one each end, 18' and 45'. The UT profiles were performed independently by

.itional profile.using a digital thickness gaug two technicians and included an Following the profiling, .the- contours were measured using a profile gauge. The results- of.the angles from the UT profiles and the actual measured contours are shown in Table The conclusions by ISI of the

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mock-up UT profiling were as follows:

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Atthchment>I ~ .

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'NRC=Incp;ction Report?50-334/89-24 Page 3 .

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"It appears- that UT. profiling techniques specified within UT-308 are adequate for- the intended purpose of determining ID configuratio Configuration is needed to confirm ID surface 1

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features that may produce ultrasonic reflector If the presence of a counterbore is detected, the actual transition angle.is not i normally as important as the fact' that there chang is.- a thickness ;

The . ability mto_ determine counterbore transition angle-4 <

. froms thew UT2/( protils p maylhave[aimarpi'naRacesracyldueTit oiseverale

, factors A Theseuinclude: C 'N i 1. . Lack of parallel reflecting surface (on counterbore- :I transition). Final transition angle may be difficult to measure due to

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radial shrinkage and weld cover pass configuratio [ Short-radius- elbow intrados curvature and thickness both

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combine to make intradcs profiling difficult. An error in

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, transducer , position measurement as small as 1/10 inch from- .i Weldnicenterline"'ma'ygresdit*in"anaepparent*transitiontenglew20 l

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to130 (degrees?steeperathantactually" exists".'a~

The'following is a summary of the process review: The end' prep tooling used on the counterbore machining would produce a - uniform contour

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variable angle is not possible.for 360* of the circumference. A 4  ! The proper inspections were performed

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and documented. The transition angle .had been physically verifie note made :during: the inspection, documented a " machine: An additional score

,; mark",' on the- transition surface, near the intrados, 1/1/4 L

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. inches-from the prep edg .

This is not consistent with the UT profile which. indicates a '

counterbore depth of 3/8 inch and a maximum machined j transition depth of 3/4 inc !

.. , The radiography film density survey indicates no significant l- density change

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datum 2 (intrados)~ differences locations..between the datum 0 (extrados) and

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~ .The UT profiling of the elbow mock-up was able to produce near n shape contours of' the ID . surface sufficient to interpret

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ultrasonic result However, . determining the angle of the

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transition from the- counterbore diameter to the mill surface f inside diameter was not possible for several reason '

$ A.- The distortions caused by welding and the presence of the ~~

? weld root penetration.

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. The differing part contours at the intrados and extrados.

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Attachment-I L

, ..lNRC Inspection Report 50-334/89-24 Page 4

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• The inaccuracies of a small diameter transducor with a

13' beam spread on a welded _and ground contour and on a

_ mill surface finis Deviations- on- the mock-up UT profile angles exceeded 20'. The E . actual measured. ID transitions deviated from the.prewelded angles

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by 7' for the119# transition and by it' for the 45' transitio ., g.gnglusionst Y

= UT- profiling using thickness .neasurements is: capable .'of determining the general ID-contour. Because of the. inherent limitations. of the UT method, determination of the angle between ron-parallel sides with the technique used, is'not

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possible.with any degree of accuracy.

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[- The counterbore transition angle is correct and uniform around the full circumference of the I There is no evidence to

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indicate a deviation from the engineering specifications.

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Distance From Weld Centerline (Inches)

, Radiography Film Density Survey '1 Figur .

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' 1 TABLE !

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ULTRASONIC AND MEASURED PROFILE C0tRffERBORE TRANSITION ANGLES TECENICIAN 'T. G. ACTUAL ;

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BOUIPNENT EPOCE DIGITAL EPOCH- DIGITAL NEASURED

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Nozzle-Elbov Veld'- p

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20' .

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.2 45'

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Mock-Up Elbow FV-1- ( 18 ') --

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DATUM'O 20' ~ -

26' 15* 22' li

l: 1-. 33*- - 24' 28'- -25'

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2 21'- -

25' 19 * - 20' ;

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32' 23' 22' t

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DATUM 0 55' -

38' 36' 32'

l 1 40' -

59' 4?' 45' -! ' -

51' 24' :31' "

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