ML20236G264

Forwards B&W Review of Ultrasonic Results of Pressurizer Support Lugs,Per Util 870518 Commitment in Response to Insp Rept 50-312/87-03.Listed Inconsistencies Noted.Corrections Will Be in Final Rept,Submitted 90 Days After Exam Complete

ML20236G264
Person / Time
Site:	Rancho Seco
Issue date:	10/20/1987
From:	Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
GCA-87-633, TAC-64153, NUDOCS 8711020475
Download: ML20236G264 (10)

Text

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MSMUD asce,ygg SACHAMENTO MUNICIPAL UTILITY DISTRICT O P. O. Box 15830, Sacramento CA 958521 ,(916) 452-3211 I

l AN ELECTRIC SYSTEM SERVING THEg fpF CALIFORNIA GCA 87-633 1981 OCT 21 A 11: 15 0CT 2 01987 U, S. Nuclear Regulatory Commission Attn: J. B. Martin, Regional Administrator

. Region V Office of Inspection and Enforcement 1450 Maria Lane, Suite 210 Halnut Creek, CA 94596 DOCKET NO. 50--312 RANCHO SECO NUCLEAR GENERATING STATION LICENSE NO. DPR-54 NRC INSPECTION 50-312/87-03, ULTRASONIC RESULTS OF THE PRESSURIZER SUPPORT LUGS

Dear Mr. Martin:

l By letter dated May 18, 1987, the Sacramento Municipal Utility District responded to a Notice of Violation concerning welds not positively identified on a system drawing. The District also responded to inspector's comments concerning the ISI Program, and committed to report findings and any corrective actions identified by the Babcock & Hilcox company review of ultrasonic results of the pressurizer support lugs. This Babcock & Hilcox report is attached.

Also, as a result of this inspection, the ISI engineer reviewed the UT test i report (ISI Figure C2.1.36 for weld 26121-33-BH). A 60* scan report was part l of the package and the required limited scan documentation was completed.

However, to ensure.that any other discrepancies in the UT test reports would not go undetected, the ISI engineer reviewed all UT test reports for the 1986 f outage. This included 36 Class 1 limited exam test reports and 32 Class 2 limited exam test reports. Of these 69 limited exams performed, three (3) inconsistencies were noted. These inconsistencies were mainly documentation errors. Specifically, the inconsistencies were:

a) Failure to identify whether the limited scan was applicable to the 0*

or 45' scan. (Fig. C2.1.13) .

i b) Checking that a limited scan was applicable for the 0*, 45*, and 60* j exam when only a 0* and 45' scan was performed. (Fig. C2.1.14)  ;

f c) Checking no limited scan on the test data sheet but including limited scan documentation for the exam. (Fig. C2.1.85) 8711020475 871020  !

PDR ADOCK 05000312 G PDR I

RANCHO SECO NUCLEAR GENERATING STATION O 1444o Twin Cities Road, Herald, CA 95638-9799;(209) 333-2935

, {, .

GCA 87-633 J.B. Hartin None of the inconsistencies-are of a technical nature. Corrections will be made in the final report which will be submitted 90 days following completion of all examinations. Several more examinations need to be performed, the final being the RCS Hydrostatic Test which will be performed during Start-Up.

Please contact me if you have any questions. Members of your staff with questions requiring additional information or clarification may contact Jack Uhl at (916) 452-3211, extension 4376.

Sincerely, l

/hhaday>an Gi Car Andognini Chief Executive Officer, Nuclear Attachment cc: G. Kalman, NRC, Bethesda (2) (w/atch)

A. D'Angelo, NRC, Rancho Seco ( " )

F. J. Miraglia, NRR, Bethesda ( "

)

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' " a t" * *- '

l. - r-NucleN Power Division J He, .OCbCUCk & WIlCOX. - Spechi Products and Integrated Fiedd Services I#  : a McDermott company 3110 Odd Fellows Road Lynchburg, VA 24501 =

(804) 847 3700

' June 12, 1987 M-87-205 l Mr.'J.- H. Uhl '

Rancho Seco Nuclear' Generating Station  !

14440 Twin Cities Road Her~ald, CA 95638

Subject:

. Review of Ultrasonic Results of-the Pressurizer

' Support Lugs

Reference:

SMUD contract 6507 B&W Reference 702-0487

, 1

Dear'Mr. Uhl:

This letter is written in response to your request that B&W

' review an unresolved item (50-312/87-03-02) identified during a recent NRC audit of the SMUD ultrasonic inspectionLresults'for the 1983 and'1985 outages on the pressurizer support lugs. The details of the NRC: observations.are as follows.  ;

Review,of' ultrasonic inspection results for the pressurizer' i support lugs (Report Numbers85-006, 85-007,85-010, and 1

'85-0014) revealed that additional indications'have been-detected since the 1983 outage. The inspection results

-show that-some of'the new' indications 1are close to previously reportedLindications suggesting possible dimensional changes. Fracture mechanics analyses have been performed by the site ISI contractor and the licensee has  !

filed the reports. However, the reports do not address the i following concerns: j

1. Are these indications growing as reported and if they are, what is the rate of growth?  !

)

2. If these new indications are fabrication welding indications not detected before, do they require 4 further evaluation to determine why these indications I were not detected before?  !

This is an unresolved item pending licensee's action relating 1to the above concerns and NRC review (50-312/87-03-02).

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MR.'J.-H. URL

- PAGE TWO- ,p -

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l; During-the'1985 evaluation ofcthe 1985 examination data,.the L1983; data' wast reviewed to access changes?from the previous examination. The,following table provides a cross reference for  ;

thel 1983'andl1985 evaluation reports.

1983 Report 1985 Report LUG' AXIS' 183-017.85-006 X-Y 183-029'85-007 Y-Z

.83-032 85-010- W-XE 83-018, 85-014: Y  !

Attachments '1 =through 4 review the 1985 ' evaluations and .

addresses the NRC concerns as' indicated by Questions 1 and 2.

' above. Attachment S'provides information on the measured limits of location and sizing errors for ultrasonic. inspections. This-attachment is : supporting information regarding B&W conclusions addressed in Attachments 1 through 4'.-

. If you have any questions, please feel free to contact either myself (804)'847-3742, or Mike ac er (804) 847-3788.

. i q ery ruly rs,

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ennis M. Turner Contracts & Proposals dmc i dmt-1710 I cc D Mixa JT Janis G Cranston i

Attachments - Evaluation Report 85-006/83-017 +

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' Evaluation Report 85-007/83-029  ;

Evaluation Report 85-010/83-032  ;

Evaluation Report 85-014/83-018 '

Measured Limits of Location and Sizing Errors M'995~W gee W."

A__-E..____u_ ---_

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l ATTACHMENT 1 '

EVALUATION REPORTS 85-006/83-017  : -X-Y AXIS LUG 3

The 1983 - data ! reported a total of'28 indications on this' weld I L from' the 450' and 600' angle beam . examinations . During'the 1985 examination :a total of 29 indications' were reported. In l

comparison, . the' 1983s.and 1985 . data matched exactly 'with the l exception of' indication numbers 207,.417, and 418.

'Indic ation' : number 207 was not recorded. during the 1983 examination,, either because- it did not exceed the- recording criteria;of 50 percent DAC or it-may have been overlooked. The data recorded for ' indication number - 207 corresponds to .a reflector l(No. 420) recorded-in 1983 and 1985 and, therefore, it is not considered a new. target -

just- mo're data on an existing reflector. Indication number. 207 was recorded with a 450 , angle beam ~ and number 420 was recorded 'with a 600 angle beam. The recorded amplitude for indication number 207 is .80 percent of DAC. The length was measured at .60 inches and the throughwall )

dimension was .50 inches. The recorded dimensions for indication numbee 420 remained . the same for both the 1983 and 1985 l

. examinations. .

The.other changes reported in 1985 concerned indication numbers 417 and~418. The table shown below provides a comparison between the 1983 and.1985 data. ,

1983 Data 1985 Data Indication No. 417 Amplitude ~ 63% 80%

\' Length , .4" .2" .i Throughwall .15" .15" C

. Indication No. 418 Amplitude 70% 70%  !

Length .25"- .55" Throughwall .25" .25" The magnitude .of the changes shown for indications 417 and 418 are within - the : limits of repeatability that can be reasonably  ;

expected'using the Section XI examination procedures. The exact i reason that indication number 207 was not recorded in 1983 cannot

-be identified. However, based on the fact none of the other  ;

indications- changed from 1983 to 1985, it is highly improbable l that the changes noted suggest any growth at all. It is more  !

. probable that the minor changes in data are attributed to repeatability limitations which are inherent with the ultrasonic j examination process. Since there is no reported growth, the indication growth rate is considered to be zero. For the 3

l purposes of the 1985 evaluations, the impact of these reported '

. changes were conservatively evaluated as if they represented '

changes in the indication. sizes. As indicated in Evaluation Report 85-006, a worse-case evaluation determined that the

]

indications were bounded by the fracture analysis performed in i 1983.

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l j

,i . b ATTACHMENT 2 EVALUATION REPORTS 85-007/83-029  : Y-Z AXIS LUG t The 1983 data reported a total of eight indications on this weld f rom ' the 450 and 600 angle beam examinations. During the 1985 examination, a total of nine indications were reported.

In comparison, the 1983 and 1985 data matched exactly with the exception of indication numbers 202 and 402.

' Indication number 202 was not recorded during the 1983 examination either because the amplitude response did not exceed the 50 percent DAC recording criteria or it may have been overlooked. The data recorded for indication number 202 corresponds to the combined indications 404 and 405 which were recorded during both the 1983 and 1985 o'utages. Indication 202 was recorded with a 450 angle beam and indications 404 and 405

• were recorded with a 600 angle beam. The maximum amplitude recorded

.65 for; indication 202 is 63 percent of DAC with a length of inches and a throughwall of .35 inches. The recorded dimensions the 1983 andfor 1985indications outages. 404 and 405 remained the same for both The other change reported involved indication number 402. A comparison of the 1983 and 1985 results is'as follows:

1983 Data 1985 Data Indication No. 402 gAmplitude 56% 56%

Length .2" .4" Throughwall .3" .3" i

As was the case for Evaluation Reports 85-006/83-017, the magnitude of the changes shown for indication 402 is within the limits of repeatability that can be reasonably expected using the Section XI examination procedures. It cannot be determined why indication 202 was not recorded in 1983. 'Each of the items mentioned above are possible explanations. However, based on the fact 1985, the,tit indications 404 and 405 did not change from 1983 to is unlikely that the addition of indication 202 represents or indicates any growth. As previously stated, the minor changes in data are attributed to repeatability limitations which are inherent with the ultrasonic examination process.

Since there is no reported growth, the indication growth rate is considered to be zero. For the purposes of the 1985 evaluations the impact of these reported changes were conservatively evaluated as if they represented changes in the indication sizes.

As indicated in Evaluation Report 85-007, a worse-case evaluation determined that the indications were bounded by the' fracture analysis performed in 1983.

i lr lhl .

ATTACHMENT 3 EVALUATION REPORTS 85-010/83-032  : W-X AXIS The 1983. data reported a total of seven indications on this weld from the 450 and 600 angle beam examinations. During the 1985 examination a total of eight indications were reported.

comparison, the 1983 and 1985 data matched exactly with the In '

exception of indications 402, 403, and 406.

Indication 406 was not recorded during the 1983 examination either because it did not exceed the 50 percent DAC recording criteria or it may,have been overlooked.

related to any other indication. recorded inThis 1983indication is not or 1985. This indication had an amplitude measurement of 63' percent DAC, just over the recording threshold. The length was recorded at .5 inches and the throughwall was measured at .4 inches. Although this was recorded as a new indication in 1985, it probably existed in 19,83 but was not recorded due to one of the reasons stated above. ,

Indications 402 and 403 did change from 1983 to 1985 according to the recorded data. The following table shows a comparison of that data. l 1983 Data 1985 Data '

Indication 402 Amplitude 70% 100%

Length

.4" .9" i Throughwall .4" .7" Indication 403 7

Amplitude 50% 63%

Length .15" .6" Throughwall 0 .6" As previously stated, the magnitude of the changes shown for 1 these indications is considered to be within the limits of repeatability that can be reasonably expected using the Section XI examination procedures. These indications are in the same general proximity as the rest of the indications (several larger than 402 and 403) which did not show any dimensional changes. If detectable growth were occurring, it is expected that the l i

remaining none.

indications would also have had some change - there was Since there is no reported growth, the idication growth rate is considered .to be zero. For the purposes of the 1985 evaluations, the impact of these reported changes were conservatively evaluated as if they represented changes in the l indication sizes. As indicated in Evaluation i Report 85-010, a i worse-case evaluation determined that the

)

indications were bounded by the fracture analysis performed in 1983. i I

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,e . - 1 ATTACHMENT 4 EVALUATION REPORTS 85-014/83-018  : Y AXIS .

The 1983 data reported . a total of 42 indications on this weld from the 450 and 600 angle beam examinations. During the 1985 i examination a total of 43 indications were reported.; In '

comparison, the 1983 and 1985 data matched exactly with the exception of indications 217 and 409.

j Indication 217 was not recorded during the 1983 examination ,

either because it did not exceed the recording threshold of 50 percent DAC or because it may have been overlooked. The maximum amplitude of this indication was 63 percent of DAW with a length of .4 inches and a throughwall measurement of .25 inches. There is no direct ~ association of this indication with any other j recorded indication; however, it is in.close proximity to other indications. Although indication 217 was not recorded in 1983, )-

it probably existed but was not recorded due to one of the reasons state,d above.

Indication number 409 did experience a slight change in recorded dimensions from 1983 to 1985. The following table provides a comparison of the data.

1983 Data 1985 Data Indication No. 409 Amplitude 63% 63% j Length .35" .45" Throughwall .30" .30" The magnitude of change for this indication is considered to be p within the limits of repeatability that can reasonably be expected using the Section XI examination procedures. Since there is no reported growth, the indication growth rate is considered to be zero. For the purposes of the 1985 evaluation, the impact of these reported changes were conservatively evaluated as if they represented changes in the indication sizes.

As indicated in Evaluation Report 85-014, a worse-case evaluation determined that the indications were bounded by the fracture mechanics analysis performed in 1983.

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L ' t. c ATTACHMENT 5 i MEASUREDLLIMITS OF LOCATION AND SIZING ERRORS:

lTheLvariationsin' data'shown in these evaluations:are'within the limits.of repeatability for!ASME Section XI UT procedures. _An excerpt from a paper. entitled "The Evaluation of the PISC'II Round Robin tests". presented atlthe.8th International' Conference on NDE in.the Nuclear-Industry'shows.the' magnitude'ofJvariations for defect location and sizing that were observed during PISC-II. Figure 5 from this article is presented. This figure-shows the distribution of location and sizing errors for-the defects-in ona of ?.he plates.

.The. upper-lleft diagram indicates the: error for location in!-the Y 1

-dimension. . The mean error is .63" with a standard deviati~n ~o of' 1.5".. The upper'right diagram indicates.the error-for location

'in the Z1 dimension. The mean error is .16" with a standard deviation of'.62". The lower left diagram indicates the error

'for. sizing in the'Y direction. The'mean error is .26" with a  ?

istandard deviation of 1.9". The lower right diagram indicates' the error for' sizing in the Z direction. The mean error is .41" i with a standard deviation of 1.1".- i I

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f. Distribution of location and si- ,

ding errors for the defects.

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