ML20129C016

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Summary Rept of Preliminary Ultrasonic Exams on Byron Unit 2 Steam Generators & Pressurizer
ML20129C016
Person / Time
Site: Byron  Constellation icon.png
Issue date: 05/24/1985
From:
COMMONWEALTH EDISON CO.
To:
Shared Package
ML20129B995 List:
References
NUDOCS 8506050386
Download: ML20129C016 (10)
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Text

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ATTACHMENT I Summary Report'of Preliminary Ultrasonic Examinations on Byron Unit 2 Steam Generators and Pressurizer I. INTRODUCTION Commonwealth Edison contracted with EBASCO Services, Inc. to perform a preliminary preservice inspection of the Byron Unit 2 steam generators and pressurizer. The techniques, personnel, and equipment used.were in accordance with Section XI and Section V requirements of the_ASME Code. Westinghouse was requested to perform a third-party review, analysis, and evaluation of the data from the Unit 2 inspection.

II. PRELIMINARY-PRESERVICE-INSPECTION EBASCO Services, Inc. performed the preliminary preservice inspection examinations in accordance with the 1977 Edition of the ASME Code with' addenda through the Summer,1978 Addenda. Welds were examined using 00 straight beam, 450 angle beam, and 600 angle beam transducers. At the request of Commonwealth

-Edison, a conservative 40% DAC reporting level was employed in-lieu of 50% DAC level required by ASME Section XI.

At the conclusion of the inspection, EBASCO recorded 45 indications that required further evaluation. These indications are listed in the attached table. The indications are scattered throughout the various welds in all four steam generators and the pressurizer.

III. WESTINGHOUSE EVALUATION OF ORIGINAL TEST DATA When evaluating the original test data, 32 of the 45 reported indications had actual a/t values which exceeded allowable a/t values when sizing to the Code required 50% DAC level. Eleven indications were found to be acceptable either because the maximum amplitude did not reach 50% DAC required to establish sizes or the actual a/t value was less than the Code allowable a/t value when sizing to 50% DAC levels. The data from two indications was confusing and required additional examinations and evaluation.

When analyzing the test data, it was noted that almost all indications are located near the inside diameter surface. This is very similar to what was observed during the preservice inspection of the Byron Unit 1 steam' generators and pressurizer.

Subsequently, a series of supplemental radiographic, ultrasonic, and visual examinations confirmed the similarity of the Unit 1 and 2 indications.

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ATTACHMENT I (cont'd)

During the repair of-the Byron Unit 1 steam generat' ors, two full thickness plugs were removed for detailed metallurgical evaluation of the defects. 'It was concluded that the discontinuities were caused by the presence of trapped slag inclusions. .The average ultrasonically-predicted-length was 2.5 times greater than the actual length-and the average ultrasonically-predicted through-wall dimension _was 6.5 times greater than the actual through-wall dimension.

Because'of the similarity of the-test data from Units 1 and 2, we believe the cause and nature of the indications from the two units are similar. However, we recognized that there will be a need to

,, -obtain samples from Unit 2~for detailed metallurgical analysis to

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confirm the indications are due to entrapped slag and that the sizing is-being exaggerated due to the close proximity to the inside diameter surface.

If it can be shown that the indications in Unit 2 are being oversized to'the same extent as was shown in the Unit 1 plugs, we believe a correction factor should be applied to the ultrasonically-predicted sizes before making Section XI acceptance evaluations. If, when analyzing the original data, a conservative correction factor (based on the actual flaw sizes in the Byron Unit 1 plugs) of 70% of the predicted' length and 25% of the predicted through-wall dimension were used to determine actual sizes, 34 of the original 45 indications are acceptable, nine indications are unacceptable, and two indications required.further testing.

IV. SUPPLEMENTAL EXAMINATIONS All of the previously discussed evaluations were made based on the original test data only. In an effort to obtain supporting information for use in making a final evaluation of marginal or questionable indications, re-examinations were performed by EBASCO under Westinghouse supervision. These re-examinations included ultrasonic tests from the outside diameter surfaces and visual, ultrasonic,' magnetic particle, and' radiographic tests from the inside diameter surface when access to the I.D. surface was possible.

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ATTACHMENT I (cont'd)

Based on'the' evaluation of both the original test data and the supplemental examinations data, it' was concluded that 40 indications meet Code acceptance criteria when using the 70% of predicted length and~25% of predicted through-wall sizing correction factors. Five indications did not meet the Code acceptance standards when using sizing correction factors. The'se

'five indications'are:

Indication-No.-

Steam Generator Weld Seam

  • Location 1 2095 SGC02 110" CCW**

2 2096 SGC05 -212-3/4" CW

3. 2097 SGC02 107-1/4" CW**

4 2097 SGC06 139-1/4" CW 5' 2098 SGC06 40-5/8" CCW

  • Weld Seams are numbered sequentially from SGC01 through SGC08 from

. bottom to' top of' vessel.

    • Sample to be removed for metallurgical evaluation.

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SIDMRf 0F BRM l#1IT 2 SIDM GEIERATOR/fRESSURI2ER IRELMlWef PSI ERIATEN " -

lb-x-- tele 75 UT If!ngth Reexamination from 0.D. --- Westin@ louse Indication In 25 . ,

Full Size Reduce Size - Recomendation -

Quponent Weld Seam location ' &iginal Exan. - UT lhru Wall . (7(M., 2fE W) '

.Atual vt Allow. #t ktual Vt - Allow. Vt ktual #t Allow. #t. - Atual #t Allow. #t 5 2095 E-02

  • 110'C0d 0.216 0437 0442 0.030 -0.138 0.037 0434' O R 7' Repair.

0.166 -0.037 0.033 0.0 31 0.034 'O.023 0.008 .0.022:

0441 ~ 0.034 * * -- -- - - - --

.5 2Ura SC-T 1081/200d 0.048 0.047 * * - -- - -

Pb rt! pair.

5m . sic-T 109 VruM - Max. aipl. = 25 K - 2 sizing dissaisions at bar. N -- -- --

m repair 5 2095 SC-02 131 1/TCod le sizing dinensions at 5(E DAC. , - -

. - - No r1 pair 5 2095 E-02 224 5/8"C0i 0. 14 4 - 0437 0.033 OR7 0.047 0437 0.012 . OR3 m repair

0.12 8 0.037, 0.030 0.027 0.0 81 0.037 0.020 0.024 0.144 0437 ~ . OR8 0.037 --- -- -- --

0.0 81 0.037- 0.020 0.027 -- -- -- --

SG 2095 SC-05 88" Od . OD75 OR4 0.015 0.020 -- -- -- --

ND repair

, 0.085 0.037- 0.016 0.023 - -- - --

$ 2D95 E-05 48" CCW 0.075 OR8 0.017 0421 -- -- -- -

m repa1r 0.075 0.029 0.014 0.021 -- -- -- --

- $ 2095 50-06 1101/2"Od 0.153 0437 0233 0.037 0.1 13 0437 OR8 OR9 ND repair 0.15 3 0.037 0.033 0.037 0.105 0.037 0.025 0.036 0.190 OA37 '0439 0.037 -- -- -- --

5m- SC-03 20 5/8'Od 0.067 0.039 * * - ,- - - --

No rt! pair ~

0487 0.060 * * - -- -- --

2m SC-03 36 3/4"Od Ib unacc@ table indications le rt! pair

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5 E96 SC-05 127" CW 0.084 0.049 OR2 0R5 -- -

m repair

TAILE I ]

. Page 2 SIM9RY OF Bm0N LMIT 2 STEM TKRATOR/lRESSURIZER FREl.MNARY PSI EVAllRT]DN

.1 thsr.oiptable 7 5 UT tength .%exanination from 0.0. Westin)ouse Indication In 2!E Full Size Reduce Size Recamendation Quponent Weld Seam location &iginal Exan. LIT Thru Wall (705L, 25% lW)'

ktual Wt Allow. #t ktual #t Allow. #t ktual #t Allow. Wt k tual W t Allow. # t 5 2096 $C-05 190 3/4"W 0.088 0.037 0B22 0.032 '-- -- -- -- 2 repair 0.075 0.037 0.018 0.027 -- - -- -

5 896 $C-05 212 3/4"W 0.091 0437 0.016 0.024 025 0.032 0.003 OR7 Repair 0.090 0.037 0.023 0.028 0.106 0.037 0.026 0.025~

0. 14 0 0D37 OD35 OR7 0.106 0.037 0.026 OR4 0.064 0.032 0.016 0.022 - -- -- --

5 aB6 3E-06 54 7/&' CW 0.0/5 OB37 0.018 0436 -- -- -- --

2 rtpair 0.058 0.037 * * - - - --

0. 12 8 0.037 OD32 0.037 -- --- --- --

0.10 0 0.037 0.025 0.036 -- --- --- -

5 2096 $C-06 229"W 0.088 0437 0.022 025 0437 0.015 0423 No repair

0. 12 5 0.037 0.031 0.029

$ 2096 $C-08 132 1/4"W Max. mpl. = 45 MC - 2 sizing dimensions at 55 MC -- -- -

No repair W MJ/ SC-01 207 3/&W 0.040 0.037 * * -- -- -- -

No repair 0.064 0437 * * -- -- -- --

5 2097 $C-02 1071/4"W 0.042 0.030 * -* 0.064 0.028 0.015 0.021 Repair 0.094 0437 OR36 0.023 0.079 0.037 0.020- 0.023 0.094 0.037 0.0236 0.030 0.14 8 0.037 0.036 0.029 OD73 ' OD32 0.018 0.023 -- -- -- --

0.048 0.030 * * -- - -- -

% 2097 $C-02 219 V4" W 0.1 10 0.037 OR8 0.030 -- -- -- - - -

2 repair -

0.094 0.037 0.024 0.026 -- -- - -

$ 897 SC-02 217" W 0.1 10 0.037 OR8 0.0 31 -- -- -- -- 2 repair

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l Page 3 SIMSRY OF BIRON tMIT 2 STE44 EMRAT0lVFRESSURIZER 1RELMNARY PSI EVALtRTI)N .-

thacceptable- 7(E UT Lf!ngth _

Reexanination frun 0.D. Westingouse Indication In 2SC Full Sim Reduce Sim Recamnendation Quponent Weld Seam location &iginal Exai. UT lhru Wall (70NL, 2SK lW)

Atual a/t Allow. #t ktual Wt Allow. a/t ktual a/t Allaw. #t Atual #t Allow. Wt S3 897 SIM2 11 V4"Od .OD97 0.037 0.024 0h30 -- -- -- --

No npair 0.097 0.037 0.024 0.029 - - - --

SG 2D97 SM-05 40 V2"C04 0.074 0.037 0.019 0.030 -- -- -- --

_ No n! pair SG 2097 5C-05 451/2"C0d 0.113 0.037 0.028 0.033 - -- - --

No repair 0.088 0437 OD22 0.027 -- -- -- --

SG 2097 $C-05 49 3/4"0d 0.041 0.032 * * - -- -- -

No repair 0.056 0.037 * * .-- --- -- ---

0.0 73 0.070 * * - - - --

S 2097 SC-05 82" CW 0.100 OD37 OD25 0.030 -- -- -- --

No mpair 0.112 0.037 0.028 0.029 -- -- - --

SG 2097 SC-06 42 V2"C04 _0.083 0.037 0.021 0.024 -- -- -- --

It mpair 0.057 . 0.033 0.015 0.023 - -- - --

0.083 0437 0421 0.024 -- -- -- --

W 2097 $C-06 43" C0d 0.0 73 0.045 * * - - - -

No repair OD35 0.031 * * -- -- --- -

W zw/ WC-06 441/2"C0d Supplerental NDE and reexanination indicate reflector most likely due to I.D. gemetry 5 2097 SC-06 139 V4"Od 0.1 13 0.025 0.028 0.021 0.075 0.025 0.019 0.021 Repair 0.066 0.030 0.033 0.023 0.158 0.037 0.040 0.026 0.368 0.037 0.092 0.037 0.210 0.037 0.053 0.037 0.278 0.037 0.069 0.027 0.240 0.037 0.060 0.026 OD75 0.037 0.019 OD22 0.193 0.037 0.048 0.037

0. 14 0 0437 0435 0425 0.12 8 0.037 0.032 0.028 5 897 SC-06 115 7/8" CCW lt unacceptable indications ro repair

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SLpWRf 0F-Sm0N tmIT 2 SIEM GEIERATOR/iRESSURIZER IRELIMNAlaf PSI ERtRTI)N ' ' -

2

. (M=*ahle 7(X UT tength .

Reexanination fmn 0.D. . Westitupouse

- Indication In - 25 . Full Sim . Reduce Size - Reconnendation -

Omponent Weld Seam Location &iginal Exan.- UT lhru Wall ' (70RL,' 25K lW) .

Atual #t Aliow. a/t ktual #t Allow a/t Atual a/t Allow. #t Rtual #t Allow. #t :

5 2097- SC- 06 1181/2" W Reflectors appear to be due to I.D. Geanetry ' lb repair _-

5 2098 50-02 101/T W 0.0 41 0.0 31 * * - - -- - No repair -

, 0 057 0.041 * * -- -- --- --

l 5 2098 5C-02 117/& CW 2 sizing dimensians at 5(X DAC .Pb repair i

SG 2098 $C-02 11 1/8" CW lb sizing dimensions at 50K [RC . No repair

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SG 2098 5C-06 40 5/T CW 0. 12 8 0.026 0.032 0.022 0.0 75 0.037 0.19 0.022 Repair 1 0.045 0.034 *

  • 0.0325 0.032 0.008 OR8 j 0.108 .0.032 0.027 0.022 0.155 0.037 0.040 0.037
0.081 0.036 *
  • 0.060 0.037 0.015 025 j 0.293 0.037 0.048 0.028 -- -- -- --

0.063 0.037 * * -- -- --- --

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4 SG 2098 SGC-06 4& CW No unacceptable indications - NB repair I SG 2098 $C-06 134 3/4" W 0.049 0.047 * * -- -- -- --

It repair.

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] N 2098 5C-06 127 m No unacceptable indications Pb repair SG 2098 SC-03 39 1/2" CW 0.041 0.030 * * -- - -- -- Pb repair 0.0 41 0.030 *- * - - -- --

j 1 Pres 1741 PL-01 7" to 17" lb unacceptable indications it repair i belaw l PC-07

! FT6 1/44 PL-U2 15 b/tr tron 0.151 U.UJ/ 0.Uzb 0.U2/ -- -- -- --

No rTpa1r j PC-02 0.109 0.037 OR74 OR78 -- -- -- --

Pres 1741 PC-03 751/2" W = 0.061 0.037 0.015 0.023 - -- -- -

tb repair 0.039 0.037

  • a. -- -- -- ---

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Page 5 t i Sl)MRY OF BWM LMIT 2 STEM GEERATOR/lRESSURIZER RtELIMNARY PSI EVM_tATI)N thacceptable 7(X UT La gth . Reexamination from 0.D. Westin$ muse Indication In 25 Full Size Reduce Size Recomendation Ompanent Weld Seam location 0-iginal Exan. UT Thru Wall - (701., 25K lW) ktual #t Allow. #t ' ktual #t Allow. a/t . Atual #t Alkw. a/t . Atual #t Allaw. #t Pres 1741 PC-04 5 V4"W 0.060 0.037 * * ' - -- - -

No rwair )

0. 0 81 0.037 0.020 0.022 - - - .  !

0.070 0.037 * * -- -- .

0.067 0.028 0.017 0.022 - - - -

)

01)67 0.037 0.029 * - -- - -

Pres 1741 PC-04 142" Di 0.232 0.037 0.047 0.037 0.084 0.072 0.020 0.036 No repair 0275 0.037 0.046 0.037 -- -- -- -

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l o Actual #t was less than allowable #t when using 70s UT Length and 50C UT thru wall dimensions.

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1 ATTACHMENT II i

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