DCL-05-024, Special Report 05-01 - Results of Steam Generator (SG) Tube Inspections Twelfth Refueling Outage for Diablo Canyon Power Plant Unit 2

Special Report 05-01 - Results of Steam Generator (SG) Tube Inspections Twelfth Refueling Outage for Diablo Canyon Power Plant Unit 2

ML050820052
Person / Time
Site:	Diablo Canyon
Issue date:	03/16/2005
From:	Jacobs D Pacific Gas & Electric Co
To:	Document Control Desk, NRC/OCM
References
DCL-05-024
Download: ML050820052 (40)

Text

Pacific Gasand Electric Company' Donna Jacobs Diablo Canyon Power Plant March 16, 2005 Mac 5Vice6 0 President Nuclear Services P.0. Box Avila 56CA 93424 Beach, 805. 545.4600 PG&E Letter DCL-05-024 Fax: 805.545.4234 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Docket No. 50-323, OL-DPR-82 Diablo Canyon Unit 2 Special Report 05 Results of Steam Generator (SG) Tube Inspections for Diablo Canyon Power Plant Unit 2 Twelfth Refueling Outage

Dear Commissioners and Staff:

In accordance with Technical Specifications (TS) 5.6.10.e and TS 5.6.10.f, provides the 90-day reporting of results of Unit 2 SG W* alternate repair criteria (ARC) tubesheet inspections and calculated steam line break leakage from application of all ARC.

In accordance with TS 5.6.10.h, Enclosure 2 provides the 120-day reporting of results of Unit 2 SG primary water stress corrosion cracking ARC inspections at dented tube support plate (TSP) intersections.

In accordance with TS 5.6.10.i and PG&E's commitment to Generic Letter 95-05, "Voltage-Based Repair Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking (ODSCC)," Enclosure 3 provides the 90-day reporting of results of Unit 2 SG voltage-based ARC inspections for TSP ODSCC, prepared by Framatone-ANP for PG&E.

If you have any questions, please contact John Arhar at (805) 545-4629.

Sincerely, Don abs ddm1/469/R0248032 Enclosures cc: David L. Prouix Diablo Distribution cc/enc: Bruce S. Mallett Girija S. Shukla p :l State'of California, Pressure Vessel Unit

Enclosure 1 PG&E Letter DCL-05-024 SPECIAL REPORT 05-01 W* ALTERNATE REPAIR CRITERIA 90-DAY REPORT DIABLO CANYON POWER PLANT UNIT 2 TWELFTH REFUELING OUTAGE NRC Reporting Requirements Diablo Canyon Power Plant (DCPP) Technical Specification (TS) 5.6.10.e requires that the results of the inspection of Wstar (W*) tubes be reported to the Commission pursuant to 10 CFR 50.4 within 90 days following return to service of the steam generators (SG). The report shall include:

1. Identification of W* tubes. PerTS 5.5.9.d.1.k, a W* tube is a tube left in service with degradation within or below the W* length.

2. W* inspection distance measured with respect to the Bottom of the WEXTEX Transition (BWT) or the top of tubesheet, whichever is lower.

3. Elevation and length of axial indications within the flexible W* distance-and the angle of inclination of clearly skewed axial cracks (if applicable).

4. The total steam line break leakage for the limiting SG per WCAP-14797, Revision 1,

("Generic W* Tube Plugging Criteria for 51 Series Steam Generator Tubesheet Region WEXTEX Expansions").

DCPP TS 5.6.10.f requires that the aggregate calculated steam line break (SLB) leakage from application of all alternate repair criteria (ARC) be reported to the Commission pursuant to 10 CFR 50.4 within 90 days following return to service of the SGs.

W* Inspections and Results This report implements the DCPP TS reporting criteria. W* ARC was implemented for the fourth time in DCPP Unit 2 during the Unit 2 twelfth refueling outage (2R12). SG inspections and repairs were completed in November 2004.

One hundred percent of the SG tubes were inspected by bobbin from tube end to tube end. One hundred percent of the hot leg top of tubesheet (TTS) WEXTEX region was inspected by Plus Point in each SG. Cold leg TTS Plus Point inspections were not required.

Table 1 provides a comprehensive list of axial primary water stress corrosion cracking (PWSCC) indications detected in the hot leg WEXTEX region during 2R12 Plus Point 1-1

Enclosure 1 PG&E Letter DCL-05-024 inspections. Not included in Table 1 are tubes with PWSCC in the plug expansion zone (PEZ). The following TS-required reporting information is extracted from Table 1:

1. Identification of W*tubes. Sixty-nine single axial PWSCC indications in 63 hot leg tubes were detected during the 100 percent hot leg top of tubesheet Plus Point inspection. Table 1 column labeled UW* Cand" identifies 62 tubes, containing a total of 68 single axial PWSCC indications (SAI), that are categorized as W* tubes because they satisfied W* ARC requirements. A total of 61 tubes, with 67 axial PWSCC indications were returned to service under W* ARC. There were no tubes with circumferential indications detected at the top of tubesheet or in the WEXTEX region.

Two tubes with axial PWSCC indications in the WEXTEX region were plugged, as described below.

• One W* tube (SG 21 R3C59) was plugged because of in situ testing performed up to 3 times normal operating differential pressure (3NOdP). This was a repeat axial PWSCC indication with a large Plus Point voltage (7.13 volts) in close proximity to the top of tubesheet (upper crack tip located 0.73 inch below the TTS). The indication could have been left in service under W*, but was required to be plugged after 3NOdP in situ .testing, even though no leakage was detected as discussed later. The tube had been deplugged in a prior outage and returned to service under W*ARC. The tube also had PWSCC in the plug expansion zone, which is discussed later.

• One new axial PWSCC indication (non-W* tube SG 23 R31C51) was plugged due to failure to meet W* ARC requirements, in that the upper crack tip (UCT) extended above BWT after accounting for nondestructive examination (NDE) uncertainty. The UCT was 0.57 inch below the TTS. The BWT was measured as 0.42 inch below the TTS. After addition of NDE uncertainty in locating the UCT relative to BWT as required by the W* methodology, the UCT is located just slightly above the BWT (by 0.13 inch), requiring the tube to be plugged. The maximum depth of the indication was 31 percent through-wall as measured by Plus Point. The indication was detectable in 2R1 1 based on a lookup review, and exhibited a slightly negative crack length growth rate.

PWSCC in Plug Expansion Zone (PEZ) in Deplugged Tubes.

Table 4 identifies 93 W* tubes for which 2R1 2 Plus Point inspections detected PWSCC in the PEZ. The tubes were deplugged in an earlier outage and returned to service under various ARC. Of these, 37 tubes are also listed in Table 1 because they have axial PWSCC in the WEXTEX region. This degradation mechanism was discovered in 1R12 (reference INPO operating experience OE 18236), and is only susceptible in tubes that were deplugged and returned to service. PEZ PWSCC occurs in the shop hard roll region, which is located about 2.75 inches above the 1-2

Enclosure I PG&E Letter DCL-05-024 tube end. The mechanical plugs (either rib plugs or roll plugs) are expanded into the tube within the shop hard roll region, and this region is termed as the PEZ. The cause of the PEZ PWSCC is likely due to the sensitization of the tube material from the tungsten inert gas (TIG) plug removal process, because the cracking is limited to the location of the expanded location of the plugs and is limited to tubes that have been deplugged using the TIG process. When the plug is removed and the tube returned to service with high reactor coolant system (RCS) temperature (about 604'F), PWSCC developed in as little as 1 cycle.

Because of W* ARC, PEZ PWSCC does not require the tube to be plugged and no accident-induced SLB is postulated. The indications are located within the original shop hard roll, such that leakage is precluded during all plant conditions.

PWSCC was not active at the time of deplugging based on proactive Plus Point inspection of full-length hot leg tubesheets of deplugged tubes in .2R9, which showed no detectable degradation (NDD).

All of the susceptible PEZ locations in all Unit 2 SGs were Plus Point inspected in 2R1 2 to gain knowledge of this damage mechanism and to assist in cause determination. The Plus Point inspection extent was specified as tube end hot to 4 inches above tube end hot. Inspection of this region is not required based on W*

ARC requirements, because PEZ locations are well below the W* lengths.

Degradation detected in the PEZ locations is acceptable to remain in service under W* ARC. Table 3 provides a matrix of the 115 potentially susceptible tubes (SG, type of plug removed, and outage removed) and shows that 93 were confirmed to have PWSCC based on 2R12 inspections. All of the 96 2R9 plugs were removed using the Framatome-ANP TIG relaxation process, and only 3 of these PEZ locations were NDD based on 2R12 inspections. All 19 of the 2R3 plugs were removed using the Westinghouse drilling process, and all of these PEZ locations were NDD based on 2R12 inspections.

For each tube with PEZ PWSCC, Table 4 provides the type of plug that was removed (Westinghouse rib plug or Framatome-ANP roll plug), the outage in which deplugging occurred (either 2R9 or 2R3), the number of PWSCC indications detected, maximum voltage, crack lower and upper extents, and location of the bottom of the shop roll transition (BRT) with respect to the tube end. Multiple axial indications were identified at 92 PEZ locations. All the indications were located in the plug expansion zones, within the shop hard roll region, as the cracks extents were located below the BRT.

As mentioned earlier, one tube with PEZ PWSCC was plugged (SG 21 R3C59), and a Framatome long rolled plug was used in both the hot and cold legs. Therefore, a total of 92 tubes with PEZ PWSCC were returned to service, 36 of which also have axial PWSCC in the WEXTEX region.

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Enclosure 1 PG&E Letter DCL-05-024

2. W* inspection distance measured with respect to BWT or TTS, whichever is lower.

For the 100 percent Plus Point hot leg TTS exam, the inspection extent relative to the TTS was specified as +2/-8.5 inches. Assuming no degradation in the W*

length, 8.5 inches below the TTS constitutes the W* inspection distance. This distance bounds W* lengths for hot leg Zone A and Zone B (5.2 inch and 7.0 inch, respectively, relative to BWT) and cold leg Zone A and Zone B (5.5 inch and 7.5 inch, respectively, relative to BWT), and includes margin for a nominal distance from BWT to TTS plus NDE uncertainty in measuring W* length. If degradation is detected in the W* region, the inspection extent must bound the calculated flexible W* length. The "W* Insp Ext wrt BWT" column in Table 1 lists the W* inspection distances measured with respect to BWT for tubes in which axial PWSCC was detected (in all cases, BWT was lower than the TTS). The W* inspection distance must be greater than or equal to the W* flexible length.

3. Elevation and length of axial indications within the flexible W* distance. See "LCT",

"UCT" and "Crack Length" columns in Table 1 for elevation of the UCT, elevation of the lower crack tip (LCT), and crack length of the axial indications. The elevations of the UCT and LCT are relative to the TTS.

Angle of inclination of clearly skewed axial cracks (if applicable). SG 23 R21 C38 repeat axial PWSCC indication in the W* length was identified to be inclined based on a review of the Plus Point data. Per W* ARC requirements, the inclination angle was measured as 37 degrees based on 0.080 inch pancake coil. The NDE uncertainty on measurement of the crack angle is 6.8 degrees for 0.080 inch pancake coil. Therefore, the total inclination angle is 43.8 degrees, less than the 45-degree plugging limit defined for W* ARC inclined indications. In addition, the total length of the indication was 0.49 inch, and after applying a growth rate of 0.119 inch/effective full power year (EFPY) over the next cycle (1.33 EFPY), the projected end of cycle (EOC) 13 crack length is 0.65 inch. This projected crack length is less than the 2.0 inches plugging limit defined for W* ARC inclined indications. Therefore, based on the shallow inclination angle and projected short length, the indication was left in service under W* ARC.

4. The total steam line break leakage for the limiting SG per WCAP-14797. SLB leakage attributed to each W* indication at EOC 12 (condition monitoring (CM)) and projected EOC 13 (operational assessment (OA)) are listed in "CM Leak Rate" and "OA Leak Rate" columns in Table 1. The W* leakage model conservatively assumes all W* indications are through-wall cracks. The total SLB leakage for each SG is provided in Table 5 (CM) and Table 6 (OA), and reflects the sum of the individual leak rates listed in Table 1. Note that SG 2-1 R3C59, SG 2-4 R13C40, SG 2-4 RI 6C1 0, and SG 24 R24C26 (two indications) were in situ leak tested and no leakage was detected. The CM leak rates for these five indications are listed in Table 1 for information only and are based on the leakage model in WCAP-14797, Revision 1. However, when calculating the total SG 2-4 leak rate in Table 5, no CM 1-4

Enclosure I PG&E Letter DCL-05-024 leakage was assigned to these five indications based on the results of the in situ leak tests.

Table 5 and Table 6 report the following SLB leak rates for condition monitoring and operational assessment, pursuant to TS 5.6.10.e.4 and TS 5.6.10.f. For W* ARC, the SLB differential pressure is conservatively assumed to be 2560 psi. For PWSCC ARC and voltage-based ARC, the SLB differential pressure is assumed to be 2405 psi.

1. Total W* ARC SLB leakage for each SG at EOC 12 (condition monitoring). The maximum leak rate is 0.571 gpm (at room temperature) in SG 2-3.

2. Total W* ARC SLB leakage for each SG at EOC 13 (operational assessment). The maximum leak rate is 0.604 gpm (at room temperature) in SG 2-3.

3. The aggregate calculated EOC 12 (condition monitoring) SLB leakage from application of voltage-based ARC, PWSCC ARC, W* ARC, and non-ARC degradation. The maximum leak rate is 0.815 gpm (at room temperature) in SG 2-4.

4. The aggregate calculated EOC 13 (operational assessment) SLB leakage from application of voltage-based ARC, PWSCC ARC, W* ARC, and non-ARC degradation. The maximum leak rate is 3.874 gpm (at room temperature) in SG 2-4.

Table 7 reports the projected EOC 12 leak rates from the prior cycle operational assessment for comparison with the as-found leak rates listed in Table 5. The prior cycle projected leak rates are higher than the as-found CM leak rates in all SGs, reflecting the conservatism of the ARC methodology.

Axial PWSCC Growth Rates Of the 69 axial PWSCC indications in the hot leg WEXTEX region that were detected in 2R12 (Table 1), 4 were new indications and 65 were repeat W* indications that had been left in service in the. prior inspection. The 4 new indications were detectable in the 2R1 1 lookup review. As a result, 69 additional growth rate data points were available for evaluation, and their average growth rate was 0.011 inch per EFPY at Thot of 6040F.

After addition of the 69 Cycle 12 data points, the updated W* growth rate distribution now consists of 256 data points from DCPP Units 1 and 2, with a 95 percent cumulative probability of 0.118 inch per EFPY at 6040F. The W* methodology requires that, if the new growth data and deletion of the oldest cycle of growth data results in a minimum of 200 data points, then the oldest cycle of data may be excluded. There are 205 data points from Unit 2 cycles 10, 11, and 12. Therefore, the following data is excluded:

Unit 2 cycles 8 and 9, and Unit 1 cycles 8, 9, 10, 11, and 12. The 95 percent cumulative probability of the 205 data points is 0.119 inch per EFPY at 6040F, and this value is used for the OA growth rate.

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Enclosure 1 PG&E Letter DCL-05-024 The actual length of Unit 2 Cycle 12 was 1.52 EFPY. The projected length of Unit 2 Cycle 13 is 1.33 EFPY.

In Situ Leak Testina In Situ Test Screening Methodology In support of W* leak rate model validation, PG&E Letter DCL-01-095 dated September 13, 2001, defined a four-step sequential screening process for determining the need for in situ leak testing of axial PWSCC indications in the WEXTEX region.

The screening criteria are described below. PG&E's assessment of the 69 axial PWSCC indications detected in 2R12 with respect to the screening criteria is tabulated in Table 2, and is also summarized below.

• Step 1: Prior leak tested W* indications with maximum Plus Point voltages greater than or equal to 1.25 times the prior leak test voltage are carried to Step 2. W*

indications with no prior leak test are also carried to step 2.

PG&E evaluation: Five W* indications had been leak tested in prior outages and for two of these indications (SG 2-1 R3C59 crack 1 and SG 24 R3C5 crack 1), the Plus Point voltage increased by more than the 25 percent threshold, so these two indications were carried to step 2. The 64 indications with no prior in situ test were also carried to step 2. Therefore, a total of 66 indications were carried to step 2.

• Step 2: Indications with maximum Plus Point voltages exceeding the critical voltage (Vcit) are leak tested independent of other parameters. Vcrit equals 4.0 volts for nondeplugged indications and 6.0 volts for deplugged indications. Indications with maximum Plus Point voltages less than Vit are carried to Step 3.

PG&E evaluation: Of the 66 indications, 38 were carried to step 2 and had been deplugged in a prior outage, and 28 had not been deplugged. One of the deplugged indications exceeded 6.0 volts Plus Point (SG 2-1 R3C59 7.13 volts), and none of the nondeplugged indications exceeded 4.0 volts Plus Point. As such, one of the indications required in situ testing due to exceeding Vcrit.. Therefore, the remaining 65 indications were carried to step 3.

• Step 3: Indications with maximum Plus Point voltages exceeding Vthr are carried to the Step 4 depth evaluation. A minimum of the five largest voltage indications are carried to the depth evaluation if less than five indications exceed the voltage threshold. Vthr equals 2.5 volts for nondeplugged indications and 4.0 volts for deplugged indications.

PG&E evaluation: Of the 28 nondeplugged axial PWSCC indications carried to step 3, two maximum Plus Point voltages exceeded the 2.5 volt Vhr threshold value 1-6

Enclosure 1 PG&E Letter DCL-05-024 (SG 2-1 R11 C48 2.78 volts and SG 2-1 R30C59 3.2 volts). Of the 37 deplugged axial PWSCC indications carried to step 3, none exceeded the 4.0-volt Vth, threshold value. Therefore, 2 indications were carried to the step 4 depth evaluation.

Becaus'e there were less than 5 indications carried to the depth evaluation, the remaining 63 indications were ranked from highest to lowest Plus Point voltage.

The 5 highest voltages were carried to step 4, all in SG 2-4: R7C38 crack 2 at 2.17 volts, R13C40 at 2.57 volts, R16C10 at 2.76 volts, R20C47 at 2.44 volts, and R24C26 crack 1 at 2.35 volts. Therefore, a total of 7 indications were carried to step 4.

Step 4 (depth evaluation): Indications with maximum depths exceeding the maximum depth leakage threshold (MDL.thr) over lengths greater than the deep crack length threshold (LLin) are leak tested. MDL thr equals 80 percent and LL-min equals 0.1 inch.

PG&E evaluation: All axial PWSCC indications in the WEXTEX region were depth profiled using the same techniques as axial PWSCC at dented tube support plate (TSP) intersections. For each indication, the flaw length exceeding 80 percent maximum depth is listed in Table 2. Of the 7 indications carried to the step 4 depth evaluation, 2 exceeded 80 percent maximum depth over 0.1 inch (SG 2-4 R13C40 and SG 2-4 R24C26 crack 1).' Therefore, these 2 indications required in situ testing.

SG 2-1 R3C59 also exceeded 80 percent maximum depth over 0.1 inch, and was required to be in situ tested per step 1 criteria. Five additional indications exceeded 80 percent maximum depth over 0.1 inch, but were excluded from in situ leak testing based on elimination in earlier steps.

2R12 In Situ Testing of W*Indications As discussed above, three indications that exceeded the in situ test screening criteria were in situ leak tested: SG 2-4 R13C40, SG 2-4 R24C26 crack 1, and SG 2-1 R3C59.

SG 2-4 R16C10 (deplugged tube) was also in situ leak tested at PG&E's discretion because the Plus Point voltage (2.76 volts) was the highest ranked voltage in the Step 3 evaluation. SG 2-4 R24C26 crack 2 was also leak tested because it was in the same tube as SG 2-4 R24C26 crack 1.

The 5 indications in 4 tubes were in situ tested (full tube length test) up to NOdP conditions, and no leakage was detected. Except for SG 2-1 R3C59, the tests were terminated and the tubes were returned to service. For SG 2-1 R3C59, PG&E decided to continue the test to the differential pressure at SLB (dPSLB), then to 3NOdP, and then the tube was plugged. R3C59 had the largest Plus Point voltage identified to date in an axial PWSCC indication returned to service under W*, and its upper crack tip was located near the BWT. No leakage'was observed at any of these higher test pressures, thus validating several assumptions: the tight WEXTEX tubesheet constraint effectively limits leakage from through-wall indications even when the indications are located in the 1-7

Enclosure 1 PG&E Letter DCL-05-024 general proximity of the BWT, and no leakage at SLB conditions would be expected if no in situ test leakage was observed at normal operating conditions.

Post in situ testing Plus Point inspections were conducted on the 4 indications returned to service (SG 2-4 R13C40, R16C10, and R24C26 cracks 1 and 2). Post in situ testing Plus Point inspections on SG 2-1 R3C59 was not required and not conducted. The post in situ eddy current results for the 4 indications are provided in Table I a, and show that the indications continued to meet W* ARC requirements for return to service. The operational assessment leak rates for these 4 indications are based on the post in situ eddy current results.

Based on the in situ test results, the total SG condition monitoring SLB leakage assessment in Table 5 assumes no leakage from the 5 indications. The CM leak rates assigned from the W* leak method for these 5 indications are provided in Table 1for information. The Table 6 total SG OA leakage assessment conservatively assumes that the 4 indications returned to service will contribute to SLB leakage at EOC 13 based on the W* leak method.

Tube Integrity Performance Monitorinq

'C .. ,. A .......................

. . . .. 1.

Condition Monitoring Performance Criteria to Limit Free Span Cracking: The UCT of W* indications returned to service under W* ARC in the prior inspection (2R1I) shall remain below the TTS at EOC 12 by at least the NDE uncertainty on locating the crack tip relative to the TTS. The "UCT to TTS" column in Table 1 provides the EOC 12 elevation of the upper crack tip relative to the top of tubesheet, accounting for NDE uncertainty in locating the crack relative to the top of tubesheet. In all cases, the EOC 12 crack tip for indications returned to service in 2R11 is below the top of tubesheet, as indicated by uYes" in the column "UCT below TTS?" Therefore, the performance criterion was satisfied for condition monitoring at EOC 12.

Accident-Induced Leakage Performance Criteria: W* leak rates under postulated SLB conditions, when combined with SLB leak rates from application of GL 95-05 voltage-based ARC and PWSCC ARC, and SLB leak rates from non-ARC degradation mechanisms, shall not exceed 10.5 gpm (at room temperature) in the faulted SG for condition monitoring and operational assessment. The 10.5 gpm limit was approved by the NRC as License Amendment (LA) 156/156. The aggregate calculated SLB leakage at EOC 12 is 0.815 gpm for the limiting SG. The aggregate calculated SLB leakage at EOC 13 is 3.874 gpm for the limiting SG. In both assessments, SLB leakage is less than the allowable limit. Therefore, the performance criterion has been satisfied for condition monitoring at EOC 12 and operational assessment at EOC 13.

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Enclosure 1 PG&E Letter DCL-05-024 Table R 2R12 Axial PWSCC Indications in Hot Leg WEXTEX Tubesheet Region (Excluding PWSCC at Tube End)

SGRwClVl SGRwDvl a ~

CTrd UCT LeVgu Crc 18gM o a,Ourt rr beo Z UCTistto Below UCT Beow UCT (NEI EOC (N+1) W. matWEA1 Inssp w FlxW In A Sa cm akOA2rod (N.1)

Le EOC OA La PrvTb NO TT sm VI, M UCT elowBWT Rte .Rate __ t Rt 3 591 7.131 1 17 .1.59 -0.13 0.86 0.86 100 .0.51 Yes 81 7.12 .0.42 0.03 No -Yes .0.35 Yes Yes .11.39 10.88 8.00 Yes 0.044 0.045 .0.13 0.00 Yes Yes a 77 0.59 1 17 .1.48 .1.35 0.13 0.13 69 .1.13 Yes 84 7.12 .0.40 0.67 No Yes .0.97 Yes Yes .10.32 9.83 7.27 Yes 0.023 0.031 0.51 0.027 Yes 7 24 0.25 1 17 -2.06 -1.951 0.11 0.11 134 .1.73 Yes 831 7.12 .0.371 1.30 No Yes 1.1.57 Yes Yes 1.11.95 11.49 7.25 Yes 10.014 0.017 1.14 0.016 Yes 7 62 4.37 I 17 .2.4 .1.48 0.92 0.92 99 -1.26 Yes 82 7.12 .1.19 001 No Yes .1.10 Yes Yes .21.40 20.12 8.06 Yes 0.045 0.045 -0.15 0.045 Yes 8 32 0.56 1 17 -2.08 .1.98 0.12 0.12 63 .1.74 Yes B2 7.12 -0.39 1.29 No Yes -1.58 Yes Yes -9.59 9.11 7.26 Yes 0.015 0.017 1.13 0.017 Yes 9 49 0.9 1 17 -2.31 -2.04 0.27 0.27 58 .1.82 Yes 81 7.12 .0.36 1.40 No. Yes .1.66 Yes Yes .10.30 985 7.41 Yes 0.014 0+017 1.24 0.016 Yes 10 49 0.21 1 17 .1.25 -1.11 0.14 0.14 37 .0.89 Yes 81 7.12 -0.3 0.53 No Yes -0.73 Yes Yes .10.14 9.75 7.28 Yes 0.027 0.044 0.37 0.031 Yes 11 37 0.44 I 17 -7.64 -7.72 0.12 29 -7.50 Yes 82 7.12 .0.41 7.03 No Yes -7.34 Yes Yes -10.93 10.43 Yes 0.001 0.001 6.87 0.001 Yes 2111 37 0.67 2. 17 .8.94 .8.76 0.1-8 0.5'7 -52 .8.54 Yes 82 7.12 .0.41 8.07 No Yes 4838 Yes Yes .10.93 170 43 7.74 Yes 0.001 0.001 5.91 0-001 Yes 11 37 0.4 3 17 .2.15 .1.88 0.27 __ 52 -1.68 Yes 82 7.12 .0.41 1.19 No Yes .1.50 Yes Yes .10.93 10.43 __ Yes 0.016 0.019 1.03 0018 Yes 11 39 1.43 1 17 .1.79 .1.63 0.16 0.16 52 .1.41 Yes 81 7.12 .0.42 0.93 No Yes .1.25 Yes Yes .10.83 10.32 7.30 Yes 0019 0.023 0.77 0.022 Yes 11 40 0.35 1 17 .0.97 .0.86 0.11 0.11 40 .0.64 Yes 81 7.12 .0.49 0.09 No Yes .0.48 Yes Yes .10.94 10.36 7.25 Yes 0.042 0.045 .0.07 0.045 Yea 11 48 2.78 i 17 .5.28 .4.80 0.48 0.48 88 4.58 Yes 81 7.12 .0.42 4.10 NO Yes .442 Yes Yes .1001 950 7.80 Yes 0034 000 3+94 000D5 Yes 13 49 0.3 1 117 .1.84 .17 .1 0.11 57 .1.51 Yes 81 7.2 e0e 0.79 N Ye -1.35 Yes Yes .10.33 9.58 7.25

• Yes 0.022 0.030 0863 0.024 Yes 23 70127 1 17-.5 135 04 0.40 66 -11.13 Ye .2 -0.22 0.85 No Ye 0.97 1Yes Yes 1-11.43 111.12 5.74 Yes 0.015 0.025 0.69 0.021 Yes 9 _03 1 17 1.11.271.106 01 061 85 .04 Yes 84 71 015 1023 Ye e 12 e e 18 37 7.12 Yes 0 OO 000 1007 0000 Yes Row. 0.302 0.365 0.8 rusttu ACl 0.257 5

10 18 0.94 48 04 1

1 20 ].1.33[I-3.1 21 I-3.2

-0.9 0.43 I0.10 0.43 0.10 741.0+88 28 Yes I-2.88 IYes 84 7.12 .0.24 0.38 181 712 0092.731 No Yes .0.52 Yes No JYesj-2.72~ Yes Yes Yes

.1224

-12.02 11.91 11.84 7.57 7.24 Yes Yes 0.031 0006 0.034 0.009 0.22 2.57 0.037 0008 Yes Yes 10 58 .8 1 21 -1.1 .0.94.10.16 0.16 3941.0721 Yes I81 7.12 58 0.06 No IYes 1-0.581 Yes Yes -12.14 11.47 7.30 Yes 0.043 0.045 .0.06 0.045 Yes 13 4 0.9 31 22 1 21 j 1. 9 1.36~

0-:226 -16 0.13 00 0.13 00 8 j

39 .1.14j Yes 81

.14 Ys A 7.1:2 0.4 083 No e -0.98 Yes Yes -11.90 11.36 7.27 Yes 0.024 0033. 0.47 0-028 Yes 52 05 083L No Ys .2Yes Yes .12.24 11.60 5 94 Ys 01 05 07 02 e 2 91 0.76 1 --095 -0.55 0.40 0.40 58 .0.33 Yes A 5.32 .0.23 004 No Yes -0.17 Yes Yes -10.06 9.73 5.74 Yes 0044 0.045 .0.12 0.045 Yes 3 69 1.51 1 40 -1.15 .080 0.35 0.35 50 -058 Yes 82 7.12 -0.34 0.16 No Yes -0.42 Yes Yes -10.06 9865 7.49 Yes 0.038 0.043 0.02 0.045 Yes 4 90 0.61 1 40 -1.06 .0.91 0.17 0.17 37 .0.69 Yes A 5.32 .0.19 0.44 No Yes -0.53 Yes Yes .10+00 9.72 5 51 Yes 0.029 0033 0.28 0.034 Yes 5 51 0.57 1 40 -2.13 -2.01 0.12 0.12 55 .1.79 Yes 81 7.12 -0.24 1.49 No Yes .1.83 Yes Yes .10.06 9.73 7.28 Yes 0013 0015 1.33 0015 Yes 5 55 1.69 1 40 -2.29 -1.94 0.35 0.35 74 -1.72 Yes 81 7.12 -0.19 1.47 No Yes .1.58 Yes Yes -10.02 9.74 7.49 Yes 0,014 0.015 1.31 0.015 Yes 6 77 0.21 1 28 -1.83 -1.74 0.09 0.09 25 -1.52 Yes 84 7.12 .042 1.04 No Yes -1.36 Yes Yes -8.58 8.05 7.23 Yes 0.013 0.020 0.88 0.017 Yes 7 52 4.53 1 28 -1.45 -0.71 0.74 0.74 100 .0.49 Yes 81 7.12 -0.28 0.15 No Yes -0.33 Yes Yes -9.01 8864 7.88 Yes 0.040 0.044 -0.01 0.045 Yes 7 59 1.37 1 40 -1.73 .1.33 0.40 040 90 -1.11 Yes 81 7.12 -0.31 0.74 No Yes -0.95 Yes Yes -10.18 9.78 7.54 Yes 0.022 0.023 0.58 0.025 Yes 7 92 1.33 1 40 -1.13 -0.78 0.35 0.35 58 -0+58 Yes A 5.32 -024 0.26 No Yes 40 Yes Yes -10.24 9.91 5.69 Yes 0.035 0.041 0.10 0.042 Yes 8 93 1.33 1 28 -089 -0.58 0.33 0.33 52 -0.34 Yes A 5.32 -0.26 002 No Yes -0.18 Yes Yes -9.88 9.50 5.67 Yes 0.045 0.045 .0.14 0.045 Yes 9 83 0.44 1 28 -1.28 -1.12 0.18 0.18 40 -090 Yes 82 7.12 -0.38 0.48 No Yes -0.74 Yes Yes -8.59 8.12 7.30 Yes 0029 0.034 0.30 0.033 Yes 12 48 0.25 1 40 -2.18 -2.09 0.09 0.09 37 -1.87 Yes 81 7.1T2 -0.29 1.52 No Yes -1.71 Yes Yes .9-98 9.58 7.23 Yes 0013 0.017 1.36 0.015 Yes 14 24 0.4 1 40 -1.50 -1.88 0.12 0.12 31 .1.48 Yes 84 7.12 -0.16 1.24 No Yes -1.30 Yes Yes -10.27 10.02 7.26 Yes 0.011 0.012 1.06 0013 Yes 18 24 0.31 1 41 -1.26 -1.13 0.13 0.13 52 -0.91 Yes 84 7.12 -0.16 0.69 No Yes -0.75 Yes Yes -9.70 9.45 7.27 Yes 0022 0024 0.53 0.027 Yes 19 71 1.01 1 26 -2.22 -1.90 0.32 0.32 52 -1.88 Yes A 5.32 -0.38 1.24 No Yes -1.52 Yes Yes -8.74 8.27 566 Yes 0.008. 0.010 1.06 0.009 Yes 21 38 0.59 1 41 -1.48 -0.99 0.49 0.49 52 -0.77 Yes 83 7.12 -0.33 0.38 No Yes -081 Yes Yea -10+23 981 7863 Yes 0.031 0038 0.22 0.037 Yes 21 83 0.61 1 40 -1.15 -0.90 0.25 0.25 67 -8 e A 5.32 .0.31 0.31 No. .Yes -05 Yes Yes -10.05 985 5.59 Yes 0.033 0.043 0.15 0.040 Yes 25 37 1.3 1 28 -1.41 -1.04 0.37 0.3 7 -0;822 Yes 84 7.2 -. 1 04 o e 06 Yes Yes -8 83 8.43 7.51 Yes 0.029 0.041 0.29 0.034 Yes 31 51 0.49 1 45 -0M.8-0.57 0.11 0.11 31 -0.35 Yes A 5.32 -0.42 -013 No No -0.19 Yes No -10.49 9.98 5.45 Yes 0.045

• 0.29 0.OD No Yes 32 55 1.45 1 28 -1.34 -0.91 0.43 0.43 71 -069 Yes A 5.32 -0.37 0.26 NO Yes -0.53 Yes Yes -8863 8.17 5.77 Yes 0.035 0.043 0.10 0.042 Yes 453 .5 1 40 -1.5.4 -1.22 0.32 0.32 67 -1.00 Yes A 5.32 -0.28 066a NO Ye -0 84 Yes Yes -927 890 5.66 Yes 002 0028 0.50 0.027 Yes 0.571 0612 0604 _____

1-9

Enclosure 1 PG&E Letter DCL-05-024 Table I 2R1 2 Axial PWSCC Indications in Hot Leg WEXTEX Tubesheet Region (Excluding' PWSCC at Tube End)

Continued -.

EOC 2R 0Dst ToaIMDCCt - 0st Di UCT UICT EOC (N+1) ~.WI Insp FeW ap cm 21 EOC OA ~ Tb SGRwClV n oCakClLC C Length r MD UCTSt eo W* W* SM UCT to Below Belmki (N+1) UICT WIIsetExt wtFeW npEt Leak OA Prod (+) La rvTb SGRwNool Length ad LengLTthC TTS WSZn egh BWT WI BWT UICT Below Can Eten e Le351atsfe Rate Reate UCT to Rate Wind Plug

- _ TTS - -BWT Rat-e- _

2 10 0.43 1 19 -1.53 .1.4 0.13 0.13 37 -1.18 Yes A 5.32 -0.2 0.92 No Yes .1.02 Yes Yes .10.52 10.23 5.47 Yes 0.012 0.022 0.76 0.018 Yes 3 ,5 2.01 1 19 -1.96 -0.82 1.14 1.14 100, -0.60 ,Yes A 5.32 -0.29 0.25 No Yes -0.44 Yes Yes .10.85 10.47 6.48 Yes 0.035 0.0-42 0.09 0.042 Yes __

3 12 0.48 1 19 .2.87 -:2.74 0.13 0.6 58 -2.52 Yes A 5.32 -0.28 2.18 No Yes -2.38 Yes Yes -10.64 10.27 5.2 Yes 0.004 0.004 2.02 0.004 Yes __

3 12 0.89 2 19 -2.53 -2.3 0.23 67 .2.08 Yes A 5.32 -0.28 1.74 No. Yes .1.92 Yes Yes -10.64 10.27 Yes 0.005 0.006 1.58 0.006 Yes 3 17 0.54 1 19 -3.74 -3.58 0.16 0.16 77 .3.36 Yes B4 7.12 -0.06 3.24 No Yes -3.20 -Yes- Yes -10.53 10.38 7.30 Yes 0.002 0.005 3.08 0.003 Yes-4 35 1.17 1 19 -1.84 -1.6 0.24 0.24 67 -1.38- Yes BI 7.12 -0.25 1.07 No Yes -1.22 Yes Yes -10.32 9.98 7.38 Yes 0.018 0.024 0.91 0.020 Yes, 5 31 0.65 1 19 -1.21 .0.931 0.28 10.28 61 -0.71 Yes 82 17.12 -0.33 0.32 No Yes -0.55 Yes Yes -10.61 10.19 7.42 Yes 0.033 0.044 0.16 0.039 Yes __

5 36 0.53 1 19 -2.13 -1.95 0.18 0.18 74 -1.73 Yes 81 7.12 -0.14 1.53 No Yes -1.57 Yes Yes -10.48 10.25 7.32 Yes 0.013 0.017 1.37 0.015 Yes __

5 1371 0.29 11 19 1-4.7 -4.54 0.16 0.6 71 -4.32 Yes Bi 7.12 -0.28 3.98 No Yes -4.16 Yes Yes -10.42 10.05 7.2 Yes 0.005 10.006 3.82 0.005 Yes __

5 37 2.08 2 19 -4.54 -4.04 0.50 __ 97 -3.82 Yes 81 7.12 -0.28 3.48 No Yes -3.66 Yes Yes -10.42 . 10.05 Yes 0.006 0.008 3.32 0.006 Yes __

5 53 2.09 1 19 -1.97 -1.57 0.40 0.40 87 -1.35- Yes 81 7.12 -0.26 1.03 No Yes -1.19 Yes Yes -10.83 . 10.48 7.54 Yes 0.018 0.021 0.87 0.020 Yes __

5 61 0.4 1 56 -10.32 -10.22 0.10 0.10 59 -10.00 Yes 81 7.12 -0.22 9.72 Yes Yes -9.84 Yes Yes -11.91 11.6 7.12 Yes 0.000 - 9.56 0.000 No 6 33 1.31 1 19 -3.11 -2.79 0.32 0.32 74 -2.57 Yes 82 7.12 -0.16 2.35 No~ Yes .2.41 Yes Yes -10.48 10.23 7.46 Yes 0.008 0.009 2.19 0.008 Yes __

7 4 0.66 1 19 -1.22 -1.06 0.16 0.16 61 -0.84 Yes A 15.32 -0.21 0.57 No Yes -0.68 Yes Yes -10.75 10.45 5.50 Yes 0.025 0.031 0.41 0.030 Yes __

24 7 38 1.77 1 19 -7.38 -7.01 0.37 1.05 77 .6.79 Yes 81 7.12 -0.25 6.48 No Yes -6.63 Yes Yes-10.55 10.21 8.21 Yes 0.001 0.001 6.32 0.001 IYes __

7 1381 2.171 2 19 1-4.91 .4.23 0.68 __ 74 -4.01 Yes 81 7.12 -0.25 3.70 No Yes -3.85 Yes Yes .10.55 10.21 Yes 0.005 0.007 3.54 0.006 Yes __

7 53 0.3 1 19 -2.75 -2.61 0.14 0.14 49 -2.39 Yes 81 7.12 .0.34 1.99 No Yes -2.23 Yes Yes .10.92 10.49 -7.28- Yes 0.010 10.012 11.83 0.011 Yes __

13 4 0.42 1 19 -1.3 -1.17 0.13 0.13 55 -0.95 Yes A 5.32 -0.23 0.66 No Yes -0.79 Yes Yes .10.44 10.12 5.47 Yes 0.022 0.027 0.50 0.027 Yes __

13 40 2.3 1 19 -2.11 -1.64 0.47 0.47 90 -1.42 Yes 82 7.12 -0.21 1.15 No Ye 1.26 Yes Yes -10.44 10.14 7.61 Yes 0.17 0021 0.99 0.023 Yes __

15 10 0.36 1 19 -1 -0.821 0.18 10.18 43 -0.60 Yes A 5.32 -0.21 0.33 1No Yes -0.44 Yes Yes -10.46 10.16 5.52 Yes 0.032 0.039 0.17 0.039 Yes __

16 10 2.71 1 19 -2.34 -1.82 0.52 0.52 77 -1.60 Yes A 5.32 -0.29 1.25 No Yes -1.44 Yes Yes .10.51 10.13 5.86 Yes 0.008 0.008 1.09 0.009 Yes:

20 47 2.44 1 19 -1.77 -1.36 0.41 0.41 71 -1.14- Yes 82 7.12 -0.25 0.83 No Yes -0.98 Yes Yes -10.47 10.13 7.55 Yes 0.021 0.026 0.67 0.023 Yes __

24 1261 2.35 11 19 1-2.06 -1.65 0.41 0.7 97 -1.43 Yes A 5.32 -0.32 1.05 No Yes -1.27 Yes Yes .10.38 9.97 5.3 Yes 0.009 0.01 2 0.89 0.020 Yes,__

24 26 0.73 2 19 152 1.6 0.16 52 .1.14 Yes A 5.32 -0.32 0.76 No Yes -0.98 Yes Yes .10.38 9.97 Y-e-s 0.0-18 - 0.60 0.027 No ___

25 64 1.8 1 19 -1.44 j.1.1j 0.34 0.34 71 -0.88 Yes 84 7.12 -0.35 0.47 No -Yes -0.72 Yes Ye -1.7 10.34 7.48 Yes 0.028 0.031 0.31 0.033 1Yes___

26 45 1 .771 1 19 -3.95 -3.59 0.38 0.36 74 .3.37 Yes 84 7.12 -0.23 3.08 No Yes -3.21 Yes Yes .1.4 10.16 7.50- Yes 0.003 0.003 2.92 0.003 Yes __

26 641 0.64 1 41 -1.01 -0.81l 0.20 0.20 52 -0.59 Yes 84 7.12 -0.38 0.17 No Ye-s -0.43 Yes Ys .1.8 10.42 7.34 Yes -0.039- . 0.01 0.045 No __

1Raw. j 0.397 0.425 I 10484 I j~nf~j~j 0.345 1

.,I

- I I-I 0

Enclosure I PG&E Letter DCL-05-024 Table la Post In Situ W* Evaluation of SG 2-4 Axial PWSCC Indications in Hot Leg WEXTEX Tubesheet Region EOC Ni~sit) La CakCak TtlM UCtoUCT ~.Dist UCT UICT EDC (N+1) Can Ex~ tentWxW Lnt Stisfied LEoC Rat SG Row Col Ind Volts No Cal LCT UCT ILeng th Lenth I bw Zon Le I BWT lUCT to Beo Below (BN+)I UCT Sate E N+T Leak 24 13 40 SAI 2.57 1 70 .1.87 .1.35 0.52 0.52 90 -1.13 Yes B2 7.12 -0.21 0.88 No Yes -0.97 Yes Yes .10.44 10.14 7.66 Yes 0.70 0.023 2-4 18 10 SAIl 2.78 1 70 .2.3 -1.78 0.54 0.54 77 l -1.54 Yes A 5.32 -0.29 1.19 No Yes -1.38 Yes Yes l10.51 10.13 588 Yes 1.03 0.009 2-4 24 28 SAI 2.88 22.03 1 70 .1.49 0.54 100 -1.27 Yes A 5.32 -0.32 0.89 No Yes -1.11 Yes Yes .10.38 997 Yes  ; 0.73 0.020 2-4 24 28 SAI 0.73 2 70 1.42 1.28 0.18 58 .1.04 Yes A 5.32 -0.32 0.68 No Yes -0.88 Yes Yes 10.38 9.97 Yes 0.50 0.027

-4 1-11

Enclosure 1 PG&E Letter DCL-05-024 Table 2 - 2R12 In Situ Test Screening of W* Indications CrackIT UT Tube P o rior ~ L80%

1-1, Insltu Insitu NOPlgnR VlflStU TkW MD Stp4Req~d Performed 3 59 SAM 7.13 1 .1.59 -0.73 Yes Yes Yes 4.67 6 4 Goto Step 2 Test NA _______ 0.71 NA YES YES 6 77 SAM 0.59 1 -1.48 -1.35 Yes ____6 4 Goto Step 2 Goto Step 3 Rank 37 0 NO____

7 24 SAM 0.25 1 .2.06 1.1.95 yes 6 4 Goto Stop2 Go to Step 3 Rank 60 0 ___ No ___

7 62 SAM 4.37 1 -2.4 . 1.48 Yes Yes 4.08 6 4 Stop N/A NWA 0.25 WA No ___

8 32 SAM 0.56 1 -2.08 -1.906 ______ 4 2.5 Goto Stop2 Goto Step 3 Rank 40 0 No ___

9 49 SAI 0.9 1 -2.31 -2.04 ___ 4 2.5 Goto Step2 Goto Step 3 Rank 26 0 No 10 49 SMI 0.21 1 .1.25 -1.11 ________4 2.5 Goto Step 2 Goto Step 3 Rank 62 0 NO____

11 37 SMJ 0.44 1 .7.84 -7.72 __ 4 -2.5 Go to Step 2 Goto Step 3 Rank 45 0 1No____

21 11 37 SMJ 0.67 2 -0.94 -6.76 __ 4 2.5 1Go to Step 2 Goto Step 3 1 Rank 30 0 NO ___

11 37 SMJ 0.4 3 .2.15 -1.88 4 2.5 Goto Step 2 Goto Step 3 Rank 49 0 NO____

11 39 SMJ 1.43 1 . 1.79 1 1.63 Yes 6 4 Goto Step 2 Goto Step 3 Rank 16 0 NO ___

11 40 SMJ 0.35 1 -0.97 -0.86 4 2.5 Go to Step 2 Goto Step 3 Rak 50No_ __

11 48 SMJ 2.78 1 -5.26 -4.80 _____4 2.5 Go to Step 2 Gt~e3(ootp _ ____ 00 tp N __

13 49 SM 0. I -18 -. 3 .4 2.5 Go toStep 2 (ootp ak 5 ___ o__

23 70 SM12 I -17 -. 5 Yes 6 4Gooe2Goot3 Rak 2 ___ 0N ____

30 59 S . I -1.7-0642. ootp oot3 ootp __03 Sl N 5 18 SMJ 0.94 1 .1.33 -0.9 4 2.__5 Goto Step 2 Go toStep3 Rank 25 _ __ 0 NO ___

10 48 SMI 0.4 11-3.21-3.1 _5 It 4_ t 2G te

_t Ran 49 10 No _

10 56 SMJ 0.65 1 -. -0.94 Yes 4 Go loStep 2 Go to Step 3 Rank 32 _ __J 0 No ___

13 43 SMJ 0.39 1 1.9-1.38 Yes 4Go toStep2 -GotoStep 3 Rank 53 _____J0 No____

3125 SMI 4.29 1 22 1.66 Yes Yes 3W2 A N/A 0.19 WA No 2_ 91 SMI 0.78 1 .0.95 -0.55 Yes 6 4 Go to Step 2 Goto Step 3 Rank 28 0 No ___

3 69 SMI 1.51 1 .1.15 -0.80 4 2.5 Go to Step 2 Go to Step 3 Rank 14 0 No____

4 90 SMI 0.61 1 .1.08 -0.91 4 2.5 Go to Step 2 Go to Step 3 Rank 35 0 No____

5 51 SMI 0.57 1 .2.13 .2.01 Yes 6 4 Go to Step 2 Go to Step 3 Rank 39 0 No ___

5 55 SMI 1.69 1 -2.29 -1.94 4 2.5 Go to Step 2 Go to Step 3 Rank 12 0 No____

6 77 SMI 0.21 1 -1.83 -1.74 Yes 6 4 Go to Step2 Go to Step 3 Rank 62 0 NO ___

7 52 SAI4.53 1 -1.45 1-0.71 Yes __Yes 13.9 6 4 Stop I WA WIA __ 0.43 1WA No _ _

7 59 SMJ 1.37 1 .1.73 -1.33 Yes 6 4 Go to Step 2 Go to Step 3 Rank 17 0.05 NO ___

7 92 SMI 1.33 1 .1.13 -0.78 Yes 6 4 Go lo Step 2 Goto Step 3 Rank 18 0 No ___

8 93 SMI 1.33 1 -0.89 -0.58 Yes 6 4 Go to Step 2 Go to Step 3 Rank 18 0 NO ___

9 63 SMI 0.44 1 -1.28 -1.12 __ 4 2.5 Goto Step 2 Go to Step 3 Rank 45 0 No____

12 48 SMI 0.25 1 -2.18 -2.09 Yes ___6 4 Go to Step2 Go to Step 3 Rank 60 0 No____

14 24 SMI 0.4 1 .1.80 -1.68 Yes ___6 4 Go toStep 2 Go to Step 3 Rank 49 0 No ___

16 24 SMI 0.31 1 -1.26 -1.13 Yes ___6 4 Go toStep2 Go to Step 3 .Rank SG 0 No____

19 71 SMI 1.01 1 -2.22 -1.90 Yes ___6 4 Go toStep 2 Go to Step 3 Rank 24 0 NO ___

21 38 SMI 0.59 1 -1.48 -0.99 Yes 6 4 Go toStop 2 Goto Step 3 Rank 37 0 NO 21 83 SMI 0.61 1 -1.15 -0.90 Yes 6 4 Go to Step 2 Goto Step 3 Rank 35 _ ___ 0 NO ___

25 37 SMI 1.3 1 .1.41 -1.04 Yes 6 4 Goto Step 2 Goto Step 3 Rank -21 ____ 0 ___ NO __

31 51 SMI 0.49 1 -0.88 -0.57 Yes __4 2.5 Goto Step 2 Goto Step 3 Rank 43 _____ 0 __ No 32 55 SMI 1.45 1 -1.34 -. 1 Ys6 4 Goto Step 2 Goto Step31 Rank 15is __ 0 ___ No __

45 37 SMI 1.55 1 -

11.54 -1.2 Ys6 4 Goto Step 2 1 3oto Step31 Rank 13 0 ____0 NOI

~I. . .1-12

Enclosure 1 PG&E Letter DCL-05-024 Table 2 - 2R12 In Situ Test Screening of W* Indications Continued

. T . Ei M T 7 Prior Crack Tube Prior Insitu SG I Row Cot Ind I Volt LCT UCT I Deplugged? Insitu Vcr I Vth Step 1 Step 2 Step 3 Rank I Manual Rank L>80%tStep 4 Insitu No Plug Insitu TW MD e Req'd Performed Voltage 9 l - - -,

2 10 l SAI l 0.43 1 -1.53 -1.4 Yes 6 4 Go to Step 2 1Go to Step 3 Rank 47 0 No 3 5 SAI 2.01 1 -1.96 -0.82 Yes l_l_Yes 1.51 6 4 Goto Step 2 Goto Step 3 Rank 8 0.85 No l 3 12 SAI 0.48 1 -2.87 -2.74 Yes 6 4 Goto Step 2 Goto Step 3 Rank 44 0 No 3 12 SAI 0.89 2 -2.53 -2.3 Yes =_=_6 4 Goto Step 2 Goto Step 3 Rank 27 0 No 3 17 SAI 0.54 1 -3.74 -3.58 4 2.5 Goto Step 2 Goto Step 3 Rank 41 0 No 4 35 SAI 1.17 1 -1.84 -1.6 Yes = 6 4 Goto Step 2 Goto Step 3 Rank 23 0 No 5 31 SAI 0.65 1 .1.21 -0.93 1 = __ 4 2.5 Goto Step 2 Goto Step 3 Rank 32 0 No 5 36 SAI 0.53 1 -2.13 -1.95 4 2.5 Goto Step 2 Goto Step 3 Rank 42 0 No 5 37 SAI 0.29 1 -4.7 -4.54 Yes = 6 4 Go to Step 2 Go to Step 3 Rank 59 0 No 5 37 SAI 2.08 2 -4.54 -4.04 Yes 6 4 Goto Step 2 Goto Step 3 Rank 7 0.27 No 5 53 SAI 2.09 1 -1.97 -1.57 Yes 6 4 Goto Step 2 Goto Step 3 Rank 6 0.05 No 5 61 SAI 0.4 1 -10.32 -10.22 4 2.5 Goto Step 2 Goto Step 3 Rank 49 0 No 6 33 SAW 1.31 1 -3.11 -2.79 = 4 2.5 Goto Step 2 Goto Step 3 Rank 20 0 No 7 4 SAW 0.66 1 -1.22 -1.06 Yes = 6 4 Goto Step 2 Goto Step 3 Rank 31 0 No 24 7 38 SAI 1.77 1 -7.38 -7.01 Yes -_._=_6 4 Goto Step 2 Goto Step 3 Rank 10 0 No 7 38 SAI 2.17 2 -4.91 -4.23 Yes 6 4 Goto Step 2 Goto Step 3 Rank 5 Goto Step 4 0 Stop No 7 53 SAI 0.3 1 -2.75 -2.61 4 2.5 Go to Step 2 Go to Step 3 Rank 57 0 No 13 4 SAI 0.42 1 -1.3 -1.17 = 4 2.5 Goto Step 2 Goto Step 3 Rank 48 0 No 13 40 SAt 2.3 1 -2.11 -1.64 Yes = 6 4 Goto Step 2 Goto Step 3 Rank 4 Goto Step 4 0.26 Test YES YES 15 10 SAI 0.36 1 -1 -0.82 Yes . 6 4 Goto Step 2 Goto Step 3 Rank 54 0 No 16 10 SAI 2.71 1 -2.34 -1.82 Yes 6 4 Goto Step 2 Goto Step 3 Rank 1 Goto Step 4 0 Stop No YES 20 47 SAI 2.44 1 -1.77 -1.36 Yes 6 4 Goto Step 2 Goto Step 3 Rank 2 Goto Step 4 0 Stop No 24 26 SAI 2.35 1 -2.06 -1.65 4 2.5 Go to Step 2 Go to Step 3 Rank 3 Go to Step 4 0.23 Test YES YES 24 26 SAI 0.73 2 -1.52 -1.36 = 4 2.5 Goto Step 2 Goto Step 3 Rank 29 0 No YES 25 64 SAI 1.8 1 -1.44 -1.1 Yes _ 6 4 Goto Step 2 Goto Step 3 Rank 9 0 No 26 45 SAI 1.77 1 -3.95 -3.59 4 2.5 Goto Step 2 Goto Step 3 Rank 10 0 No 26 64 SAI 0.64 1 -1.01 -0.81 4 2.5 Goto Step 2 GotoStep 3 Rank 34 0 No 1-13

Enclosure 1 PG&E Letter DCL-05-024 Column -Tables 1 and 2 l Legend and Notes for Tables 1 and 2 SG Steam generator Row Tube Row Col Tube Column SAI Single axial indication Volts Peak voltage from Plus Point coil Crack No Crack number Cal Calibration group LCT Elevation (inch) of lower crack tip (LCT), relative to the top of tubesheet (TTS).

UCT Elevation (inch) of upper crack tip (UCT), relative to the TTS.

Crack Length Length of crack (inch)

Total Length Total length of multiple cracks (inch) - -

MD adj Maximum depth of crack as adjusted by PWSCC ARC software, percent through-wall UCT to TTS Adjusted elevation (inch) of the UCT relative to TTS, including ANDEcT.Trs (Plus Point NDE uncertainty on locating the crack tip

__ relative to the TTS).

UCT below TTS? If the adjusted elevation of the UCT (including NDE uncertainty) is located below TTS, then the tube is a W* candidate.

W* Zone W* tubesheet zone based on crack location.

Wh Length W* length Is 7.12 inch for hot leg Zone B and 5.32 Inch for hot leg Zone A, and Includes ANDEw (NDE uncertainty in measuring the

___ ____ ___ W

• depth).

BWT Elevation of the bottom of the WEXTEX transition (BWT), inch, measured by bobbin relative to the TTS.

Dist UCT to BWT Distance (inch) from the UCT to BWT, minus ANDEcT.BWr (Plus Point NDE uncertainty on locating the crack tip relative to the BWT).

UCT below W*? If the UCT is located below the W* length, then the tube is a W* tube. Any type of degradation below the W' length is acceptable.

UCT below BWT? If the UCT is located below BWT, then the tube is a W* candidate.

EOC (n+l) UCT Elevation (inch) of UCT relative to TTS at the end of the next operating cycle, based on growing the UCT at 0.119 inch/EFPY.

EOC (n+l) UCT below If the UCT is below TTS at the end of the next cycle, a free span indication is precluded and the tube Is a W* candidate.

UTS?

W* Cand? If the UCT is below BWT and the EOC (n+l) UCT is projected to be below TTS at the end of the next cycle, then the tube is a W*

tube (candidate).

Inspect Extent Elevation of Plus Point inspection relative to TTS (inch).

W* inspection distance with respect to BWT, also referred to as the W* inspection distance (inch). This Is the Plus Point Inspection W* Inspect Ext BWT extent relative to BWT. The W* inspection distance below BWT is equal to the Plus Point Inspection extent below TTS, plus measured distance from BWT to TTS, plus bobbin NDE uncertainty in locating BWT relative to TTS. The W* inspection distance must be greater than or equal to the flexible W* length.

Flexible W* length relative to BWT (inch), equal to W* Length + -CIl (total axial crack length) + NcL*ANDEcL (number of Indications Flex W* Length times Plus Point NDE uncertainty with measuring length of axial cracks) + NcL*ACG (number of indications times crack growth, 0.119 inch/EFPY)

Insp Extent Satisfied The inspection extent must be greater than the flexible W* length.

CM Leak Rate Condition monitoring SLB leak rate, gpm at room temperature, based on distance of UCT to BWT, using Figure 6.4-3 of WCAP-14797 Rev 1. No accident leakage Is assigned to indications with UCT below W* length.

2R1 1 OA Pred Leak Rate Leak rate (gpm at room temperature) from prior cycle operational assessment prediction, provided to compare against as found CM 1-14

Enclosure 1 PG&E Letter DCL-05-024 Column - Tables I and 2 Legend and Notes for Tables 1 and 2 leak rate.

Dist EOC (N+l) UCT to Distance (inch) of the UCT relative to BWT at end of the next cycle, minus ANDEcTrsw (Plus Point NDE uncertainty on locating the BWT crack tip relative to the B\T), based on growing the UCT at 0.119 inch/EFPY. This entry is not applicable to indications that are

___ ____ ___ plugged.

OA Leak Rate Operational assessment leak rate, gpm at room temperature, at end of next cycle based on distance of EOC (n+1) UCT to BVvT, using Figure 6.4-3 of WCAP-14797 Rev 1. No accident leakage is assigned to an indication with UCT below W* length.

Prev W^ Indication? If the indication was left in service in the prior cycle, it is classified as a previous W* indication (repeat indication). Otherwise, the

___ ____ ___ indication is new.

Deplugged? Tube was deplugged In a prior outage.

Tube Plugged? Tube was plugged during the current outage.

Prior In Situ? The tube was in situ tested In a prior outage.

Prior In Situ Voltage If prior In situ testing was performed, the Plus Point voltage of the Indication In the outage that In situ leak testing was performed.

Vcr Critical voltage for determining need for In situ testing Vth Threshold voltage for determining need for In situ testing Steps 1 through 4 Logical steps used for screening Indications for In situ testing based on NRC commitments Rank Plus Point voltage ranking of Indications as required by in situ screening Step 3 Manual Rank Five largest Plus Point voltages are manually ranked for further screening L >80% TW MD The length of the indication that exceeds 80 percent maximum depth, based on Plus Point line-by-line sizing.

In Situ Reqgd? Identifies indications that require in situ leak testing based on the four step screening logic In Situ performed The indication was in situ tested.

1-15

Enclosure 1 PG&E Letter DCL-05-024 Table 3 Unit 2 Deplugged Tube Population and 2R12 Plus Point Inspection Results Unit 2 Tubes Deplugged and Inservice in U2C12 SGRoll RibToa SG 2R11 2R10 2R9 2R11 2R10 2R9 2R3 Total 21 _ _ _ __ _ _ 11 11 22 l l 21 21 23 20 19 drill 39 24 38 6 44 Total 90 . 6 19 115 Tubes with Plus Point Indications in Plug Expansion Zone (PEZ)

SGRoll Rib__TotRi SG 2R11 2R10 2R9 2R11 2R10 2R9 2R3 Total 21 9 9 22 = _ 21 _ __ ___ 21 23 _ _ _ _ _ _ _ _ 20 _ _ __ _ _ __20 24 37 6 43 Total 87 ,____ 66 93 Note: All plugs removed in 2R9 used the TIG removal process, and full length tubesheet Plus Point inspections were performed after plug removal and no degradation was detected. All plugs removed in 2R3 used the drill process.

1-16

Enclosure 1 PG&E Letter DCL-05-024 Table 4 2R12 PWSCC Indications in the Plug Expansion Zone (PEZ)

Outage TpPlgRemva Tub e d Crack Lower Crack Upper Bottom of Roll SG Row Col Pelug Type Plug Removad Tube eod Ind Max Volts Extent relative to Extent relative to Transition Reoe R____ eed dMto IniaonTEH, Inch TEH. inch (BRT) 21 3 59 2R9 Roll TIG MAI 2 5.31 0.49 1.98 2.45 21 6 77 2R9 Roll TIG MAI 8 5.86 0.61 2.31 2.86 21 7 24 2R9 Roll TIG MAI 4 5.46 0.56 2.44 3.01 21 11 39 2R9 Roll TIG MAI 8 5.47 0.59 2.23 2.73 21 23 43 2R9 Roll TIG MAI 5 6.36 0.62 2.23 2.69 21 23 47 2R9 Roll TIG MAI 9 5.23 0.68 2.15 2.66 21 23 70 2R9 Roll TIG MAI 7 5.81 0.61 2.46 2.91 21 26 48 2R9 Roll TIG MAI 7 4.49 0.47 2.23 2.64 21 27 49 2R9 Roll TIG MAI 7 4.4 0.49 2.27 2.73 22 4 28 2R9 Roll TIG MAI 7 5.39 0.54 2.03 2.65 22 5 3 2R9 Roll TIG MAI 4 5.14 0.53 1.88 2.51 22 6 24 2R9 Roll TIG MAI 8 3.53 0.41 2.04 2.51 22 7 27 2R9 Roll TIG MAI 7 7.1 0.45 2.05 2.62 22 8 36 2R9 Roll TIG MAI 7 5.42 0.41 1.98 2.51 22 8 43 2R9 Roll TIG MAI 8 5.47 0.42 2.04 2.47 22 10 56 2R9 Roll TIG MAI 8 6.18 0.44 2.11 2.57 22 12 39 2R9 Roll TIG MAI 5 5.82 0.51 2.17 2.6 22 13 43 2R9 Roll TIG MAI 7 7.11 0.43 2.07 2.51 22 14 45 2R9 Roll TIG MAI 7 6.42 0.46 2.12 2.52 22 15 42 2R9 Roll TIG MAI 8 5.09 0.5 2.09 2.49 22 16 49 2R9 Roll TIG MAI 8 6.93 0.53 1.94 2.53 22 19 15 2R9 Roll TIG MAI 4 5.5 0.52 2.43 2.97 22 19 75 2R9 Roll TIG MAI 9 3.78 0.42 2.04 2.59 22 20 73 2R9 Roll TIG MAI 4 6.19 0.55 2.13 2.56 22 21 41 2R9 Roll TIG MAI 4 5.02 0.41 1.92 2.56 22 22 44 2R9 Roll TIG MAI 8 5.42 0.59 2.12 2.58 22 23 23 2R9 Roll TIG MAI 6 4.63 0.42 2.13 2.52 22 25 44 2R9 Roll TIG MAI 6 5.39 0.49 2.14 2.61 22 31 25 2R9 Roll TIG SAI 1 6.07 0.5 1.91 2.5 22 41 42 2R9 Roll TIG MAI 5 4.97 0.42 2.05 2.75 23 2 91 2R9 Roll TIG MAI 7 4.39 0.49 1.98 2.62 23 4 47 2R9 Roll TIG MAI 9 4.71 0.59 2.1 2.59 23 5 51 2R9 Roll TIG MAI 8 5.68 0.59 2.18 2.85 23 6 77 2R9 Roll TIG MAI 7 3.16 0.48 2.02 2.5 23 7 52 2R9 Roll TIG MAI 8 4 0.65 2.13 2.82 23 7 59 2R9 Roll TIG MAI 8 4.82 0.56 2.06 2.88 23 7 92 2R9 Roll TIG MAI 7 5.13 0.6 2.01 2.54 23 8 93 2R9 Roll TIG MAI 7 5.36 0.51 2.03 2.57 23 12 48 2R9 Roll TIG MAI 8 4.91 0.71 2.62 3.35 23 14 24 2R9 Roll TIG MAI 4 6.24 0.55 2.09 2.5 23 16 24 2R9 Roll TIG MAI 7 4.7 0.59 2.15 2.49 1-17

Enclosure 1 PG&E Letter DCL-05-024 Table 4 2R12 PWSCC Indications in the Plua Exnansion Zone (PEZ)

Outage Tbe Crack Lower Crack Upper Bottom of Roll SG Row Col Plug TemPlug Removal Tut e tend Ind Max Volts Extent relative to Extent relative to Transition

____ RRemoved emvdMto niainTEH, Inch TEH, Inch (BRT) 23 17 70 2R9 Roll TIG MAI 9 4.56 0.57 1.98 2.46 23 19 71 2R9 Roll TIG MAI 9 3.47 0.61 1.99 2.52 23 21 38 2R9 Roll TIG MAI 7 4.36 0.51 2.08 2.46 23 21 83 2R9 Roll TIG MAI 7 3.96 0.6 2.07 2.52 23 25 37 2R9 Roll TIG MAI 8 4.87 0.56 2.1 2.44 23 32 55 2R9 Roll TIG MAI 8 3.8 0.58 2.15 2.8 23 33 34 2R9 Roll TIG MAI 6 5.32 0.38 . 2.08 2.6 23 44 44 2R9 Roll TIG MAI 8 3.75 0.47 2.04 2.72 23 45 37 2R9 Roll TIG MAI 8 4.08 0.5 2.27 2.82 24 2 10 2R9 Roll TIG MAI 7 5.32 0.68 2.38 2.97 24 3 5 2R9 Rib TIG MAI 8 2.21 0.92 2.05 2.81 24 3 12 2R9 Roll TIG MAI 8 4.35 0.72 2.22 2.85 24 4 35 2R9 Roll TIG MAI 8 5.88 0.76 2.29 2.85 24 4 59 2R9 Roll TIG MAI 9 5.33 0.65 2.34 2.85 24 5 37 2R9 Rib TIG MAI 7 1.66 1.01 2.11 2.8 24 5 53 2R9 Rib TIG MAI 10 1.86 1.15 . 2.01 2.88 24 6 15 2R9 Roll TIG MAI 6 4.68 0.48 2.07 2.52 24 6 73 2R9 Roll TIG MAI 7 4.35 . 0.68 2.24 2.84 24 7 4 2R9 Roll TIG MAI 4 4.1 0.56 2.28 2.74 24 7 38 2R9 Roll TIG MAI 10 5.04 0.69 2.22 2.83 24 8 29 2R9 Roll . TIG MAI 8 4.22 0.46 2.08 2.52 24 9 29 2R9 Roll TIG MAI 8 4.18 0.56 2.07 2.5 24 11 74 2R9 Roll TIG MAI 8 5.4 0.74 2.15 2.84 24 11 87 2R9 Roll TIG MAI 4 5.06 0.58 1.45 2.8 24 12 23 2R9 Roll TIG MAI 7 3.94 0.55 2.21 2.63 24 13 40 2R9 Roll TIG MAI 8 3.24 0.59 - 2.04 2.72 24 15 10 2R9 Roll TIG MAI 6 5.06 0.47 2.08 2.56 24 15 74 2R9 Roll TIG MAI 7 4.92 0.67 2.11 2.84 24 15 75 2R9 Roll TIG MAI 8 3.66 0.66 2.15 2.83 24 15 76 2R9 Roll TIG MAI 6 5.03 0.64 2.2 2.84 24 16 10 2R9 Rib TIG MAI 9 2.47 0.75 2.02 2.49 24 19 28 2R9 Roll TIG MAI 9 4.89 0.5 2.27 2.66 24 19 41 2R9 Roll TIG MAI 6 5.69 0.68 2.49 2.81 24 19 74 2R9 Roll TIG MAI 10 3.88 0.67 2.18 2.85 24 20 47 2R9 Rib TIG MAI 6 3.02 1.12 2.27 2.84 24 20 77 2R9 Roll TIG MAI 3 3.54 0.72 2.36 2.86 24 21 34 2R9 Roll TIG MAI 7 4.58 0.41 2.03 2.48 24 22 44 2R9 Roll TIG MAI 8 5.3 0.58 2.27 3.02 24 22 48 2R9 Roll TIG MAI 10 3.94 0.52 2.51 3.02 24 23 75 2R9 Roll TIG MAI 7 4.43 0.69 2.13 2.8 24 25 64 2R9 Roll TIG MAI 9 5.33 0.6 2.07 2.83 1-18

Enclosure 1 PG&E Letter DCL-05-024 Table 4 W134 DWAtI. InrItfl.finen in tha DPoin =vnnncinn 7,nnn 10F7l Outage T Pl Removal Tube end Crack Lower Crack Upper Bottom of Roll SG Row Col Plug ype ug Mehod Indication Ind Max Volts Extent relative to Extent relative to Transition

__ RRemoved em vd Mto niainTEH, Inch TEH, Inch (BRT) 24 25 73 2R9 Roll TIG MAI 8 4.08 0.65 2.1 2.91 24 25 79 2R9 Roll TIG MAI 10 4.26 0.65 2.21 2.83 24 27 23 2R9 Roll TIG MAI 8 1.67 0.64 2.19 2.87 24 29 53 2R9 Rib TIG MAI 3 1.88 1.24 1.77 2.59 24 35 34 2R9 Roll TIG MAI 8 3.66 0.95 2.48 2.87 24 36 25 2R9 Roll TIG MAI 6 5.23 0.75 2.44 2.92 24 36 67 2R9 Roll TIG MAI 7 4.84 0.54 2.08 2.53 24 37 46 2R9 Roll TIG MAI 7 4.27 0.77 2.41 2.9 24 38 65 2R9 Roll TIG MAI 5 2.09 0.58 1.52 2.59 24 41 47 2R9 Roll TIG MAI 6 4.6 0.59 1.88 2.9 24 42 41 2R9 Roll TIG MAI 7 1.5 1.12 2.31 3.02 Table 5 DCPP Unit 2 Condition Monitoring Steam Line Break Leak Rates for Alternate Repair Criteria EOC 12 Condition Monitoring Leak Rate SG 2-1 SG 2-2 SG 2-3 SG 2-4 (gpm at room temperature) ___ _ .

W* ARC (Note 2) 0.257 0.121 0.571 0.345

.Voltage-Based ARC (Note 1) 0.15 0.09 0 0.47 PWSCC ARC 0 0 0.0 0 Non-ARC degradation 0 0 0 0 Aggregate ARC 0.407 0.211 0.611 0.815 Note 1: Voltage-based ARC leak rates are described in Enclosure 3.

Note 2: Five indications were in situ leak tested and did not leak at SLB pressure, and no SLB leak rate is assigned to these indications when calculating the total SG leak rate.

Table 6 DCPP Unit 2 Operational Assessment Steam Line Break Leak Rates for Alternate Repair Criteria EOC 13 Operational Assessment Leak Rate l SG2-1 l SG2-2 l SG 2-3 SG2-4 (gpm at room temperature) l I l l W* ARC 0.289 0.140 0.604 0.484 Voltage-Based ARC (note 1) 0.95 0.64 0.40 3.25 PWSCC ARC 0 0 0 0 Non-ARC degradation 0 0 0 0 Aggregate ARC 1.239 0.780 1.004 3.734 Note 1: Voltage-based ARC leak rates are described in Enclosure 3.

Table 7 DCPP Unit 2 Prior Cycle W* ARC Leak Rate Predictions I Predicted EOC 12 Leak Rate (from prior cycle OA) l SG 2-1 1 SG 2-2 l SG 2-3 l SG 2-4 (gpm at room temperature) I l _ l I W* ARC 1 0.365 l 0.145 l 0.612 l 0.425 1-19

Enclosure 2 PG&E Letter DCL-05-024 SPECIAL REPORT 05-01 TSP PWSCC ALTERNATE REPAIR CRITERIA 120-DAY REPORT DIABLO CANYON POWER PLANT UNIT 2 TWELFTH REFUELING OUTAGE NRC Reporting Requirements PWSCC ARC for axial PWSCC at dented TSP was implemented for the second time in DCPP Unit 2 during 2R12. 2R12 SG inspections and repairs were completed in November 2004.

For implementation of ARC for axial PWSCC at dented TSPs, DCPP TS 5.6.10.h requires that the results of the condition monitoring and operational assessments be reported to the NRC within 120 days following completion of the inspection. This report implements the DCPP TS reporting criteria.

To satisfy the TS, this report includes the following:

• Tabulations of indications found in the inspection, tubes repaired, and tubes left in service under the ARC.

• Growth rate distributions for indications found in the inspection and growth rate distributions used to establish the tube repair limits.

• Plus Point confirmation rates for bobbin-detected indications when bobbin is relied upon for detection of axial PWSCC in less than or equal to 2-volt dents.

• For CM, an evaluation of any indications that satisfy burst margin requirements based on the Westinghouse burst pressure model, but do not satisfy burst margin requirements based on the combined Argonne National Laboratory (ANL) ligament tearing and through-wall burst pressure model.

• Performance evaluation of the operational assessment (OA) methodology for prediction of flaw distributions as a function of flaw size.

• Evaluation results of number and size of previously reported versus new PWSCC indications found in the inspection, and the potential need to account for new indications in the operational assessment burst evaluation.

• Identification of mixed mode (axial PWSCC and circumferential) indications found in the inspection and an evaluation of the mixed mode indications for potential impact on the axial indication burst pressures or leakage. In addition, as committed in DCL-02-045, performance of a trending analysis to assess the potential for increasing mixed mode affects over time.

• Any corrective actions found necessary in the event that condition monitoring requirements are not met.

2-1

Enclosure 2 PG&E Letter DCL-05-024 Dented TSP Plus Point Inspection Scope The 2R12 Plus Point dent inspection scope for greater than 2-volt dents was based on greater than 2-volt dents called in the prior 2R1 1 outage. The greater than 2-volt dent population and number of greater than 2-volt dents inspected by Plus Point in 2R12 is provided in Table 1.

The dented TSP inspection criteria and expansion plan criteria described below are based on PG&E letter to the NRC dated April 16, 2001, and WCAP-15573, Revision 1, "Depth-Based SG Tube Repair Criteria for Axial PWSCC at Dented TSP Intersections -

Alternate Burst Pressure Calculation."

Plus Pointinspection criteriafor axial PWSCC left in service Plus Point inspections shall be conducted on 100 percent of axial PWSCC indications at dented TSP intersections that were left in service in Unit 2 Cycle 12. Forty-seven axial PWSCC indications had been left in service in Cycle 12 under PWSCC ARC.

Plus Pointinspection criteriafor > 2 and < 5-volt dents and for > 5-volt dents On a SG-specific basis, Plus Point inspections shall be conducted on 100 percent of

> 5 volt dented intersections up to and including the highest hot leg TSP elevation where PWSCC (at any size dent), circumferential indications (at any size dent), or axial outside diameter stress corrosion crack (ODSCC) not detected by bobbin (AONDB) (at

> 5-volt dent) have been previously detected in that SG in the prior two outages, or current outage (expansion required), plus 20 percent of > 5-volt dents at the next higher TSP elevation. In each SG where 100 percent hot leg TSP Plus Point inspections are not required, Plus Point inspections shall be conducted on 20 percent of > 5-volt dents at each hot leg TSP. For any 20 percent sample, a minimum of 50 > 5-volt dents shall be inspected. If the population of > 5-volt dents at that TSP elevation is less than 50, then 100 percent of the > 5-volt dents at that TSP shall be inspected.

On a SG-specific basis, Plus Point inspections shall be conducted on 100 percent of

> 2 and < 5-volt dented intersections up to and including the highest hot leg TSP elevation where PWSCC (at any size dent), circumferential indications (at any size dent), or > 2-inferred-volt AONDB (at > 2 and < 5-volt dent) have been previously detected in that SG in the prior two outages, or current outage (expansion required),

plus 20 percent of > 2 and < 5-volt dent at the next higher TSP elevation. If a SG is free from PWSCC (at any size dent), circumferential indications (at any size dent) and

> 2-inferred-volt AONDB (at > 2 and < 5-volt dent), then Plus Point inspections shall be conducted on 20 percent of > 2 and < 5-volt dents at 1H. For any 20 percent sample, a minimum of 50 > 2 and < 5-volt dents shall be inspected. If the population of > 2 and

< 5-volt dents at that TSP elevation is less than 50, then 100 percent of the > 2 and

< 5 volt dents at that TSP shall be inspected.

The highest TSP where PWSCC or circumferential indications have been found inthe prior two outages in Unit 2 is 5H for SG 2-2, 3H for SG 2-3, and 3H for SG 2-4. In 2-2

Enclosure 2 PG&E Letter DCL-05-024 SG 2-1, no PWSCC or circumferential indications have been detected. Because all inferred bobbin voltages for AONDB indications have been less than 2-volts, AONDB indications do not factor into the inspection scope. Based on this information, the following Plus Point dent inspection criteria was implemented to meet the requirements specified above:

> 5-volt dents:

• 100% in all SGs, both hot leg and cold leg.

> 2 and < 5-volt dents:

• SG2-1: 20% at 1H

• SG 2-2: 100% from 1H to 5H, 20% at 6H

• SG 2-3: 100% from 1H to 3H, 20% at 4H

• SG 2-4: 100% from 1H to 3H, 20% at 4H In addition, the above 2 to 5-volt dent Plus Point inspection plan was augmented by Plus Point inspection of 100% of 2 to'5-volt dented TSPs in the hot and cold legs that had never been inspected by Plus Point in any prior outage. These dents were located at TSPs outside of the defined critical areas and buffer zones, and mostly located in the cold legs. No PWSCC was detected in this augmented inspection, thus confirming that the defined critical areas are adequate.

In 2R12, no axial PWSCC or circumferential indications were detected in SG 2-1, no axial PWSCC or circumferential indications were detected above 5H in SG 2-2, and no axial PWSCC or circumferential indications were detected above 3H in SGs 2-3 and SG 2-4. Therefore, no expansion of the Plus Point dent inspection program was required.

Plus Point inspection for less than or equal to 2-volt dents One hundred percent of the tubes were inspected by bobbin coil, and the bobbin coil was relied upon for detection of axial PWSCC in < 2-volt dents. As a result, Plus Point inspection of < 2-volt dents was only required if the bobbin coil detected a distorted inside diameter support signal,(DIS) at a dented TSP intersection. One hundred percent of DIS indications were inspected by Plus Point.

Plus Point inspection criteriafor detection of circumferentialindications at dents On a SG-specific basis, if a circumferential indication or > 2-inferred-volt AONDB is detected in a dent of uxY volts in the prior two outages, or current outage (expansion required), then Plus Point inspections shall be conducted on 100 percent of dents greater than ux - 0.3"-volts up to the affected TSP, plus 20 percent of dents greater than uX - 0.3"-volts at the next higher TSP. "X" is defined as the lowest dent voltage where a circumferential crack or > 2-inferred-volt AONDB was detected in that SG. For any 20 percent sample, a minimum of 50 "x - 0.3"-volt dents shall be inspected. If the 2-3

Enclosure 2 PG&E Letter DCL-05-024 population of "x - 0.3"-volt dents at that TSP elevation is less than 50, then 100 percent of the Mx - 0.3"-volt dents at that TSP shall be inspected.

The smallest dent in which a Unit 2 circumferential crack has been detected in the prior two outages was 6.74 volts (in SG 2-2). Thus, dents greater than 6.44 volts are required to be inspected (i.e., 6.74 - 0.3 = 6.44). The existing 2-volt dent inspection cutoff for 2R12 Plus Point inspection is much less than the 6.44-volt threshold for circumferential cracking, and was therefore sufficient. In 2R12, 3 circumferential indications at dented TSPs were detected, and the associated dent voltages were much greater than 5-volts. Therefore, no Plus Point expanded inspection scope for dents less than 2-volts was necessary.

Tabulations of indications found in the inspection, tubes repaired, and tubes left in service under the ARC.

Sixty-four axial PWSCC indications at dented TSP intersections were detected in 2R12.

Table 5 provides a tabulation of indications, including the following information:

• For plugged indications, the reason for plugging

• Identifies the indication as repeat or new.

• Adjusted NDE measurements of length, maximum depth, average depth, voltage, and crack location relative to the TSP centerline.

• OA burst pressure (free span and total length) using the ANL and EPRI burst model.

A burst pressure of 6100 psi in Table 5 represents a predicted burst pressure

> 6100 psi since all pressures predicted to exceed 6100 psi are grouped at 6100 psi to reduce computer storage requirements in the analysis.

• OA SLB leak rate (free span and total length) using the ANL ligament-tearing model.

The PWSCC ARC allows axial PWSCC indications to remain in service at dented TSP intersections if the following PWSCC ARC conditions are satisfied for each indication:

• OA free span burst pressure (based on the combined ANL ligament-tearing and EPRI through-wall burst pressure model) exceeds 3NOdP. The 3NOdP burst pressure is equal to 4419 psi.

• OA total length burst pressure (based on the combined ANL ligament-tearing and EPRI through-wall burst pressure model) exceeds 1.4 dPSLB. The 1.4 dPSLB burst pressure is equal to 3367 psi, based on a dPSLB of 2405 psi (pressurizer PORV setpoint plus uncertainty).

• OA free span leak rate, when combined with free span leak rates from other degradation mechanisms, is less than 1 gpm (0.7 gpm at room temperature) in a faulted SG.

2-4

Enclosure 2 PG&E Letter DCL-05-024

• OA total length leak rate, when combined with leak rates from other degradation mechanisms, is less than 10.5 gpm (room temperature) in a faulted SG.

• The indication is less than 40 percent through-wall outside the TSP crevice.

In addition to the above PWSCC ARC conditions, axial PWSCC indications must satisfy the following exclusion criteria in order to remain in service:

• The indication is not located at a TSP intersection located in the wedge region or 7H17C high bending stress region.

• The indication is not located at a TSP intersection that contains cracked or missing TSP ligaments.

• The indication is not located at a TSP intersection that contains another degradation mechanism.

• The indication is not located in a tube that contains another repairable indication.

Forty-seven axial PWSCC indications at dented TSPs had been left in service in 2R1 1 due to PWSCC ARC. Following 2R12 Plus Point inspection, one of the repeat ,

indications was resized as two separate indications based on a lookup of 2R1 1 data.

Therefore, there were 48 repeat indications. After application of PWSCC ARC requirements, 7 of the 48 repeat axial PWSCC indications were plugged. Five indications were plugged because they were greater than 40 percent through-wall outside the TSP crevice. One indication was plugged because it was located at the same TSP as one of the indications that exceeded 40-percent through-wall depth outside the TSP. One indication was plugged because a circumferential indication was detected at the same TSP as the axial indication, referred to as a PWSCC mix mode indication.

In 2R12, 16 new axial PWSCC indications at dented TSPs were detected, sized by Plus Point, and applied to PWSCC ARC requirements. One indication was plugged because it was greater than 40 percent through-wall outside the TSP crevice. Two indications were plugged because they were located at the same TSP as the indication that exceeded 40-percent through-wall depth outside the TSP. One indication was plugged due to combined ID and OD cracking at the same TSP location.

The indications that were located outside the TSP region were reviewed to determine the need for in situ pressure testing in accordance with the criteria in WCAP-1 5128, Revision 1. Namely, if CM for axial PWSCC at dented TSPs predicts free span leakage or free span burst pressures less than 3NOdP, then in situ pressure testing is required.

These conditions were not predicted by CM, and therefore no in situ pressure testing of axial PWSCC at dents was required nor performed.

In summary, 53 axial PWSCC indications at dented TSPs were returned to service in 2-5

Enclosure 2 PG&E Letter DCL-05-024 2R12: 41 repeat indications and 12 new indications.

Growth rate distributions for indications used to establish the tube repair limits and for indications found in the inspection The growth rate distribution used to establish the tube repair limits was based on prior outage growth data. The methodology for establishing the growth rate was established in WCAP-1 5573, Revision 1,as further explained in PG&E Letters DCL-02-023 and DCL-02-045. The methodology is summarized below:

• If there are at least 200 points in each of the last two cycles on the unit being inspected, the most conservative growth distribution from the last two cycles shall be used.

• If there are at least 200 points over the last two cycles on the unit being inspected, the growth distribution to be used is the more conservative of the combined data or either of the two cycles.

• If there are less than 200 points over the last two cycles on the unit being inspected, the growth distribution to be used shall contain data from both units over the last two (or three if necessary) cycles of each unit until 200 data points are obtained. The data from ea6h'cycle is compared for consistency in growth magnitude. If a given cycle has lower growth rates than other cycles, it is not included in the growth distribution.

In preparation for 2R12, the third bullet applied. Over 2R10 and 2R11, there are only 94 data points, less than the 200 points required for a unit-specific growth rate distribution. Therefore, the 2R1 0 and 2R1 1 data was supplemented by data from 1R11 and 1R12, resulting in a total of 428 data points over the last two cycles from each unit:

2R10 (45), 2R11 (49), 1R11 (119),A1R12 (215). The oldest growth data, that is, data from 1R8, 2R8, 1R9, 2R9, and 1R10, does not require evaluation and is excluded per the above methodology because over 200 data points are already available from the more recent inspections. For each remaining data set (2R10, 1R11, 2R11, and 1R12),

cumulative growth distributions were developed and compared for length, maximum depth, and average depth. The prior cycle growth rate cumulative probability distributions (CPD) are provided in Table 2. Per the ARC methodology, these data sets were evaluated for exclusion. To bound the ARC method, PG&E chose to develop a conservative growth distribution based on the lower bound of the cumulative probability growth distributions from the combined data sets (2R10, 1R11, 2R11, 1R12). This lower bound growth distribution was separately developed for growth in length, maximum depth, and average depth. The lower bound growth rate CPD is provided in Table 2 and was used in the 2R12 Monte Carlo preliminary OA calculations for determining the need for tube repair.

In accordance with WCAP-1 5573, Revision 1,growth rates that could impact the upper tail of the growth distribution were evaluated during 2R12. The methodology requires that if new growth data causes the growth distribution above 90 percent probability to be more conservative, the new data are added to the growth distribution for the OA.

2-6

Enclosure 2 PG&E Letter DCL-05-024 Sixty-one additional growth rate data points were established in 2R12, 48 from repeat indications and 13 from new indications. The CPD of the 2R12 growth data is provided in Table 2.

The final OA growth rate distribution that was used for determining the need for tube repair was developed in a similar method that was used to establish the growth rate distribution for the preliminary OA. PG&E developed a conservative growth distribution based on the lower bound of the cumulative probability growth distributions from the combined data sets including the 2R12 data set (i.e., 2R10,1 RI1, 2R11,1 R12, 2R12).

Once again, this lower bound growth distribution was separately developed for growth in length, maximum depth, and average depth. The lower bound growth rate CPD is provided in Table 2 and was used in the 2R12 Monte Carlo final OA calculations for determining the need for tube repair. For maximum depth, the final OA and preliminary OA growth distributions were identical. The final OA was slightly more conservative than the preliminary OA in the 0.06-inch and 0.07-inch-length bins, and in the 1 percent average depth bin.

Table 3 compares the 90 and 95 percentile growth values per EFPY at 6040 F for 2R1 0, 1RI1, 2R11, 1R12, and 2R12.

Plus Point confirmation rates for bobbin-detected indications when bobbin is relied upon for detection of axial PWSCC in less than or equal to 2 volt dents.

In 2R12, the bobbin coil was relied upon for detection of axial PWSCC in < 2-volt dents.

As identified in Table 4, there were 192 DIS indications detected by bobbin at less than or equal to 2-volt dented TSP intersections with non-repeat PWSCC indications.

Tracking of Plus Point confirmation rates for repeat PWSCC indications tubes is not required because these known flaws are inspected by Plus Point regardless of the bobbin call.

All DIS indications were inspected by Plus Point. Only 1 of the 192 DIS indications were confirmed as PWSCC by Plus Point, for a Plus Point confirmation rate of less than 1 percent, or a 99 percent-bobbin overcall rate. The high bobbin overcall rate is greater than the approximately 90 percent overcall rate generated during the bobbin coil performance test documented in WCAP-1 5573, Revision 1. The high bobbin overcall rate is overly conservative to establish a high probability of detecting significant axial PWSCC indications in < 2-volt dents.

For condition monitoring an evaluation of any indications that satisfy burst margin requirements based on the Westinghouse burst pressure model, but do not satisfy burst margin requirements based on the combined Argonne National Laboratory (ANL) ligament tearing and through-wall burst pressure model.

This item is not applicable, because all indications satisfied CM burst margin requirements based on the combined ANL ligament tearing and EPRI through-wall burst pressure model as shown in Table 5. The total length CM burst requirement for EOC 12 was 3367 psi at 1.4 dPSLB, based on dPSLB of 2405 psi (pressurizer power 2-7

Enclosure 2 PG&E Letter DCL-05-024 operated relief valve (PORV) setpoint plus uncertainty). The free span length CM burst requirement for EOC 12 was 4419 psi, based on 3NOdP.

Performance evaluation of the operational assessment (OA) methodology for prediction of flaw distributions as a function of flaw size.

Benchmarking was performed of the repeat PWSCC ARC indications that had been left in service in Unit 2 Cycle 12. The actual EOC 12 CM burst pressure of all repeat indications exceeded the default free span and total length burst pressure of 6100 psi using the ANUEPRI model, and had no SLB leakage using the ANL ligament-tearing leakage model. With one exception (2R11 indication in SG 2-2 R19C17), all projected EOC 12 burst pressures exceeded the default free span and total length burst pressure of 6100 psi, using the ANLIEPRI model, and no SLB leakage was projected at EOC 12 using the ANL ligament-tearing leakage model. Based on this performance evaluation via benchmarking, the OA methodology is determined to be adequately conservative.

Evaluation results of number and size of previously reported versus new PWSCC indications found in the inspection, and the potential need to account for new indications in the operational assessment (OA) burst evaluation.

As discussed above, there were 64 axial PWSCC indications detected in 2R1 1: 48 repeat indications and 16 new indications. One of the new indications had no prior Plus Point inspection. Of the new indications, 15 had prior Plus Point inspections in 2R1 1, of which 13 were detectable based on a lookup of the 2R11 data. Because the number of new flaws is relatively small and all new indications have OA burst pressures well in excess of burst margin requirements, there is no need to account for new indications in the OA burst evaluation.

Identification of mixed mode (axial PWSCC and circumferential) indications found in the inspection and an evaluation of the mixed mode indications for potential impact on the axial indication burst pressures or leakage. In addition, performance of a trending analysis to assess the potential for increasing mixed mode affects (e.g.. circumferential crack depths, burst pressure reductions, increased leakage rates) over time.

For PWSCC ARC, a mixed mode indication is defined as an axial PWSCC indication and a circumferential indication (either PWSCC or ODSCC) occurring at the same dented TSP intersection. One mixed mode indication (axial PWSCC and circumferential PWSCC) was detected during 2R12 (SG 2-2 R5C33 1H). Axial PWSCC was left in service in 2R1 1 at this location under PWSCC ARC. The circumferential PWSCC was detectable in the 2R1 1 data based on a lookup performed in 2R1 2.

Table 6 provides the NDE measurements of all of the TSP circumferential indications detected in 2R12, including SG 2-2 R5C33 1H. The dent was measured as 20.74 volts.

For SG 2-2 R5C33 1H, the 2R12 null distance of 70 degrees (0.53 inch) was measured between the axial and circumferential indications using the 0.080 pancake coil technique at 600 Khz. The 0.53 inch null distance exceeds the 0.25 inch separation distance requirement, and therefore the flaw is not interacting. Even if the flaw was interacting, the NDE average depth of the circumferential flaw is 43.7 percent, including 2-8

Enclosure 2 PG&E Letter DCL-05-024 95 percent NDE uncertainty, which is less than the 75 percent average depth threshold value for mixed mode affects. In addition, neither the axial nor circumferential indications are 100 percent through-wall at any point. The circumferential indication is 64 percent maximum depth, including 95 percent NDE uncertainty. The measured maximum depth of the axial indication is 35 percent (adjusted NDE), and has no predicted SLB leakage at 95/50 confidence for CM. The CM burst pressure of the axial indication is in excess of 6100 psi. Based on this mixed mode assessment, there is no potential impact on the axial PWSCC indication burst pressure or leakage.

There are several conditions that require evaluation to determine the need for corrective actions. These are discussed below:

• If an interacting mixed-mode indication is found to have led to a reduction in the axial indication burst pressure by more than 10 percent and to less than 4000 psi, or to have caused an indication to not satisfy burst margin requirements, the burst margin requirements for implementation in the OA at the next and subsequent outages must be increased by the percentage reduction in the burst pressure found for the mixed mode indication. As discussed above, because this condition did not occur, there are no corrective actions needed to adjust burst margin requirements for future operational assessments.

• If an interacting mixed-mode indication is found, and the axial indication condition monitoring predicts SLB leakage at 95/50, and the circumferential indication has

> 50 percent average depth including NDE uncertainty, then the CM leak rate for the axial indication must be increased by a leakage factor. In addition, the OA SLB leak rate for each SG must be increased by a leakage factor. As discussed above, because this condition did not occur, there are no corrective actions needed to adjust SLB leak rates for CM or OA.

• If a previously Plus Point-inspected TSP intersection is found to have a circumferential indication with average depth > 80 percent after accounting for NDE uncertainty, then the OA SLB leak rate for each SG must be increased by a leakage factor. All of the TSPs with circumferential indications detected in 2R12 were previously Plus Point inspected in 2R1 1. The deepest 2R1 2 circumferential indication was 51.2 percent average depth, including NDE uncertainty, less than the 80 percent average depth threshold. Therefore, no corrective actions are needed to adjust the OA SLB leak rates.

In response to NRC request for additional information, PG&E Letter DCL-02-045 dated April 18, 2002, committed to perform a trending analysis in the 120-day report to assess the potential for increasing mixed mode affects (e.g., circumferential crack depths, burst pressure reductions, increased leakage rates) over time. Since no burst pressure reductions or leakage rate multipliers have been required, there is no data to trend for these parameters. Trending of circumferential depths and number of circumferential indications is provided in Figures 1,2, and 3. Figure 1 provides all DCPP Units 1 and 2 TSP PWSCC and ODSCC circumferential indication measured "adjusted" average depths versus year detected. The adjustments do not include NDE uncertainty. The 2-9

Enclosure 2 PG&E Letter DCL-05-024 average depths show a fairly flat trend line. Figure 2 data is a subset of Figure 1, showing the mixed mode circumferential indication average depths versus year detected. Only three circumferential indications have been detected at the same TSP with an axial PWSCC indication that had been returned to service (1R11 SG 1-2 R11C81, 1R12 SG 1-2 R36C53, and 2R12 SG 2-2 R5C33). The Figure 2 average depths show a decreasing trend line. Figure 3 provides the cumulative distribution of the number of DCPP Units 1 and 2 TSP PWSCC and ODSCC circumferential indications detected over time. The trend does not indicate a large increase in the numbers of circumferential indications in recent inspections.

This trending assessment does not indicate a need to modify any mixed mode evaluation criteria such as applying the criteria that could lead to an increase in the burst margin requirements.

Any corrective actions found necessary in the event that condition monitoring requirements are not met.

This item is not applicable, because all indications satisfied condition monitoring burst margin requirements and leakage margin requirements.

All calculated CM burst pressures, evaluated at 95 percent probability and 50 percent confidence (95/50), exceeded the default-pressure of 6100 psi for total length and for free span, well in excess of the 3367 psi total length SLB burst margin requirement and the 4419 psi free span burst margin requirement, using both the Westinghouse model and the ANLITW model.

CM single indication SLB leak rates were evaluated at 95 percent probability and 50 percent confidence (95/50), using the ANL ligament-tearing model. No free span leakage and no total length leakage were calculated.

2-10

Enclosure 2 PG&E Letter DCL-05-024 Table I

> 2-Volt Dent Population and Number Plus Point Inspected in 2R12 2 to 5-volt Dents (based on 2R1 1 dent analysis) and Number Inspected (shaded)

TSP SG 2-1 SG 2-2 SG 2-3 SG 2-4 Total Inspected 1H -V-83 - *6 , - ______._ ___;_--?

2H 1 20 3 .... 3 _ _, _ _

3H _ _ _ _ 2 2 _ _ _ _ : _ : _- _ 24 . - _ _ _ _ _ _ _

4H 2 2 239  :-- 4 5H 3 2 1 2 - ; ; _ _

6H 1 i 9 1 , 0 _ ;" _

7H 17 12 10 38 Total dents 30 158 39 73 Note: The above 2 to 5-volt dent Plus Point inspection plan was augmented by Plus Point inspection of 100% of 2 to 5-volt dented TSPs in the hot and cold legs that had never been inspected by Plus Point in any prior outage.

> 5-volt Dents (based on 2R1 1 dent analysis) and Number Inspected (shaded)

TSP SG 2-1 SG 2-2 SG 2-3 SG 2-4 Total Inspected 1H l 0' 318 EN l - - 0 319 2H __ 0 X-o;7 i -1. 8 3H __ 0. 1: 1 26-. 28 4H . 0 - 85 1.- - .1 87 5H 2 Be -h. -0 2 6H 0 . - 0 0 7H 0 0 2 5 7 7C 0 .1 0 -

6C 0 0 ~

0 50C 00 4 0 0 5 0 5 3C 0 . 0 0 0 0 2C 0. .0 0 0 0 1C 0 0 O. 1: 1 Total dents 2 411 11 34 458 2R12 inspection criteria (same criteria used in 2R11):

• 100% of > 5 volt dents, both hot leg and cold leg

• SG 21: 20% of > 2 and < 5-volt dents at 1H

• SG 22: 100% of > 2 and < 5-volt dents from I H to 5H (critical area), 20% at 6H

• SG 23, 24: 100% of > 2 and < 5-volt dents from 1H to 3H (critical area), 20% at 4H

• All 20% samples shall contain a minimum of 50 dents. If the population of > 2 and < 5-volt dents at the TSP elevation is less than 50, then inspect 100% of > 2 and < 5-volt dents at the TSP.

2-11

Enclosure 2 PG&E Letter DCL-05-024 Table 2 - Axial PWSCC Cumulative Probability Di tribution (C D)Growth Rates per EFPY 604°F 2R10 data IRI1I data 2R11 data 1R1 2 data 2R12 Prelim OA 2R12 data 2R12 Final OA Length (inch) Freq CPD Freq CPD Freg CPD Freq CPD Lower bound CPD Freg CPD Lower bound CPD 0 8 0.178 77 0.647 19 0.388 78 0.363 0.178 22 0.379 0.178 0.01 7 0.333 13 0.756 4 0.469 24 0.474 0.333 7 0.500 0.333 0.02 5 0.444 9 0.832 13 0.735 45 0.684 0.444 13 0.724 0.444 0.03 11 0.689 6 0.882 3 0.796 17 0.763 0.689 7 0.845 0.689 0.04 5 0.800 3 0.908 2 0.837 19 0.851 0.800 3 0.897 0.800 0.05 5 0.911 5 0.950 2 0.878 14 0.916 0.878 1 0.914 0.878 0.06 2 0.956 2 0.966 4 0.959 7 0.949 0.949 1 0.931 . 0.931 0.07 0 0.956 1 0.975 0 0.959 5 0.972 0.956 1 0.948 0.948 0.08 1 0.978 3 1.000 0 0.959 1 0.977 0.959 2 0.983 0.959 0.09 0 0.978 0 1.000 2 1.000 4 0.995 0.978 1 1.000 0.978 0.1 0 0.978 0 1.000 0 1.000 1 1.000 0.978 0 1.000 0.978 0.11 0 0.978 0 1.000 0 1.000 0 1.000 0.978 0 1.000 0.978 0.12 0 0.978 0 1.000 0 1.000 0 1.000 0.978 0 1.000 0.978 0.13 1 1.000 0 1.000 0 1.000 0 1.000 1.000 0 1.000 - 1.000 MD (%TW fraction) Freg CPD Freg CPD Freq CPD Freq CPD Lower bound CPD Freg CPD Lower bound CPD 0 14 0.311 59 0.496 30 0.612 63 0.293 0.293 20 0.345 0.293 0.01 1 0.333 9 0.571 1 0.633 8 0.330 0.330 0 0.345 0.330 0.02 2 0.378 12 0.672 2 0.673 20 0.423 0.378 6 0.448 0.378 0.03 2 0.422 9 0.748 0 0.673 16 0.498 0.422 2 0.483 0.422 0.04 0 0.422 4 0.782 2 0.714 19 0.586 0.422 8 0.621 0.422 0.05 3 0.489 5 0.824 3 0.776 28 0.716 0.489 1 0.638 0.489 0.06 1 0.511 4 0.857 3 0.837 7 0.749 0.511 7 0.759 0.511 0.07 4 0.600 5 0.899 3 0.898 11 0.800 0.600 3 0.810 0.600 0.08 6 0.733 2 0.916 1 0.918 7 0.833 0.733 2 0.845 0.733.

0.09 3 0.800 4 0.950 2 0.959 9 0.874 0.800 4 0.914 0.800 0.1 1 0.822 3 0.975 0 0.959 10 0.921 0.822 0 0.914 0.822 0.11 2 0.867 1 0.983 2 1.000 2 0.930 0.867 1 0.931 0.867 0.12 1 0.889 0 0.983 0 1.000 7 0.963 0.889 2 0.966 0.889 0.13 1 0.911 1 0.992 0 1.000 1 0.967 0.911 1 0.983 0.911 0.14 1 0.933 1 1.000 0 1.000 1 0.972 0.933 0 0.983 0.933 0.15 1 0.956 0 1.000 0 1.000 2 0.981 0.956 0 0.983 0.956 0.16 0 0.956 0 1.000 0 1.000 2 0.991 0.956 1 1.000 0.956 0.17 0 0.956 0 1.000 0 1.000 0 0.991 0.956 0 1.000 0.956 0.18 1 0.978 0 1.000 0 1.000 0 0.991 0.978 0 1.000 0.978 0.19 0 0.978 0 1.000 0 1.000 0 0.991 0.978 0 1.000 0.978 0.2 1 1.000 0 1.000 0 1.000 2 1.000 1.000 0 1.000 1.000 AD (%TW fraction) Freq CPD Freq CPD Freg CPD Freg CPD Lower bound CPD FreI CPD Lower bound CPD 0 14 0.311 46 0.387 27 0.551 53 0.247 0.247 14 0.241 0.241 0.01 3 0.378 17 0.529 5 0.653 25 0.363 0.363 6 0.345 0.345 0.02 1 0.400 18 0.681 6 0.776 24 0.474 0.400 6 0.448 0.400 0.03 4 0.489 6 0.731 2 0.816 17 0.553 0.489 4 0.517 0.489 0.04 3 0.556 6 0.782 0 0.816 23 0.660 0.556 3 0.569 0.556 0.05 5 0.667 9 0.857 4 0.898 23 0.767 0.667 7 0.690 0.667 0.06 2 0.711 4 0.891 0 0.898 18 0.851 0.711 7 0.810 0.711 0.07 4 0.800 3 0.916 0 0.898 12 0.907 0.800 5 0.897 0.800 0.08 2 0.844 4 0.950 2 0.939 6 0.935 0.844 2 0.931 0.844 0.09 2 0.889 0 0.950 1 0.959 2 0.944 0.889 1 0.948 0.889 0.1 1 0.911 2 0.966 1 0.980 4 0.963 0.911 0 0.948 0.911 0.11 0 0.911 1 0.975 1 1.000 1 0.967 0.911 0 0.948 0.911 0.12 1 0.933 1 0.983 0 1.000 2 0.977 0.933 2 0.983 0.933 0.13 1 0.956 0 0.983 0 1.000 2 0.986 0.956 0 0.983 0.956 0.14 0 0.956 2 1.000 0 1.000 3 1.000 0.956 0 0.983 0.956 0.15 0 0.956 0 1.000 0 1.000 0 1.000 0.956 0 0.983 0.956 0.16 0 0.956 0 1.000 0 1.000 0 1.000 0.956 0 0.983 0.956 0.17 1 0.978 0 1.000 0 1.000 0 1.000 0.978 1 1.000 0.978 0.18 0 0.978 0 1.000 0 1.000 0 1.000 0.978 0 1.000 0.978 0.19 0 0.978 0 1.000 0 1.000 0 1.000 0.978 0 o 1.ooo 0.978 0.2 1 1.000 0 1.000 0 1.000 0 1.000 1.000 0 1.000 1.000 2-12

Enclosure 2 PG&E Letter DCL-05-024 Table 3

._ Growth Rates per EFPY at 604 0F C D Length inch MD % AD %

Cycle Data points 90% 95% 90% 95% 90% 95%

2R10 45 0.050 0.057 11.83 14.68 9.13 12.14 IR11 119 0.035 0.050 6.67 8.58 6.14 8.03 2R11 49 0.051 0.056 7.01 8.51 5.37 8.43 1R12 215 0.050 0.060 9.69 11.37 6.88 9.14 2R12 58 0.041 0.068 8.55 11.84 6.92 8.53 Table 4 DIS Confirmation Rates SG 2-1 SG 2-2 SG 2-3 SG 2-4 Total Number of bobbin DIS in less than or equal to 2 volt dented TSP intersections (excludes 28 40 60 64 192 repeat PWSCC indications)

Number of new PWSCC indications confirmed by Plus Point Plus Point confirmation rate 0% 0% 0% 1.6% <1%

Bobbin DIS overcall rate 100% 100% 100% 98.4% >99%

2-13

Enclosure 2 PG&E Letter DCL-05-024 Table 5 - 2R11 PWSCC ARC Summary of Analysis Results l Unadjusted Adjusted NDE - CM Westinghouse Model OA ANL-TW Model Total Total ToalTotal Crack Cal New or 2R112 Plug Length MD AD Length MD AD Max Frm T PeSsrLekg Burst FSeLenge Le Burst akageF S nt Leagta SG Row Col TSP No Num Repeat Reason (In.) (%()(in.)()() Volt psimgpm Pressur aaage psis Pressur Lekpg ekg us Lekge psi___p__Prsi gpm psi gpmPrs p 2 2 19 01H 1 20 Repeat >40% DOP 0.15 64 40.4 0.12 49.0 31.4 0.47 0.40 0.52 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 2 40 01H 1 32 New 0.10 40 23.9 0.10 23.0 13.7 0.34 -0.54 -0.44 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 2 41 011H 1 21 Repeat 0.20 45 31.6 0.20 33.0 23.2 0.56 .0.45 0.65 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 4 28 01H 1 20 Repeat 0.26 35 25.8 0.26 32.0 23.5 0.82 -0.02 0.24 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 4 34 04H 1 20 Repeat _ 0.11 40 23.3 0.11 35.0 20.4 0.25 0.06 0.17 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 5 3 0111 1 21 Repeat 0.32 36 22.6 0.30 20.0 15.5 0.47 -0.20 0.10 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 5 26 011H 1 20 Repeat_ 0.18 55 33.5 0.15 29.0 16.4 0.69 -0.31 -0.16 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 5 33 011H 1 20 Repeat Mix Mode 0.21 35 24.3 0.21 35.0 24.3 0.84 -0.33 -0.12 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 6 24 011H 1 20 Repeat 0.23 46 31.5 0.23 35.0 24.0 0.60 -0.34 -0.11 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 6 31 0111 1 20 Repeat 0.19 64 45.5 0.19 49.0 34.8 0.82 -0.36 -0.17 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 6 31 011H 2 20 New 0.13 32 24.0 0.13 29.0 21.7 0.41 -0.13 0.00 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 6 36 0111 1 20 Repeat 0.10 38 17.2 0.10 20.0 9.1 0.48 -0.20 -0.10 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 6 49 0111 1 21 Repeat 0.07 48 33.2 0.07 48.0 33.2 0.27 -0.24 -0.17 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 7 5 011H 1 21 Repet 0.17 42 28.9 0.14 39.0 27.6 0.38 -0.06 0.08 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 7 27 0111 1 20 Repet_ 0.17 38 28.8 0.17 35.0 26.5 0.46 0.14 0.31 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 7 32 0111 1 20 Repeat 0.17 61 34.3 0.15 38.0 25.4 0.82 -0.29 -0.14 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 8 36 0111 1 20 Repeat . 0.44 38 29.9 0.46 38.0 29.3 0.94 -0.26 0.20 6100 0.000 6100 0.000 6100 0.000 5784 0.000 2 8 43 04H 1 21 Repeat 0.21 54 40.0 0.21 42.0 31.1 0.79 -0.10 0.11 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 8 52 01H 1 21 Repeat >40% DOP 0.36 70 43.1 0.29 54.0 37.8 1.42 0.34 0.63 6100 0.000 6100 0.000 5828 0.000 5704 0.000 2 9 32 0111 1 20 Repeat 0.15 40 23.4 0.13 29.0 15.9 0.64 -0.11 0.02 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 10 21 04H 1 20 Repeat 0.40 61 29.4 0.23 35.0 19.5 0.50 -0.04 0.19 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 10 30 0111 1 27 New 0.11 57 35.0 0.11 38.0 23.3 0.50 -0.27 -0.16 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 10 32 0111 1 28 New 0.09 18 10.9 0.09 20.0 12.2 0.27 0.46 0.55 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 11 17 0111 1 24 New 0.12 30 19.7 0.12 30.0 19.7 0.41 -0.47 -0.35 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 11 30 011H 1 20 Repeat 0.17 46 28.3 0.17 35.0 21.6 0.55 -0.23 -0.06 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 11 30 011H 2 20 New 0.13 64 40.8 0.08 40.0 28.0 0.74 --0.40 -0.32 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 11 30 0111 3 20 New 0.09 46 28.3 0.06 32.0 19.6 0.39 0.47 0.53 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 12 39 011H 1 21 Repeat 0.14 57 35.6 0.09 33.0 22.1 0.61 -0.15 -0.06 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 13 25 03H 1 20 Repeat 0.29 49 36.6 0.26 35.0 25.1 0.68 -0.16 0.10 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 13 41 0111 1 21 Repeat 0.19 36 26.8 0.19 28.0 20.8 0.68 -0.19 0.00 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 14 45 011H 1 21 Repeat . 0.12 33 17.4 0.09 20.0 12.2 0.44 =.0.04 0.05 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 15 22 011H 1 20 Repeat 0.17 38 24.9 0.17 35.0 22.9 0.53 -0.09 0.08 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 15 42 011H 1 21 Repeat 0.20 33 21.1 0.20 28.0 17.9 0.43 -0.06 0.14 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 15 51 011H 1 21 Repeat 0.14 33 20.2 0.14 20.0 12.2 0.29 -0.23 -0.09 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 16 30 02H 1 55 New IDIOD 0.10 39 25.8 0.10 30.0 19.8 0.47 0.18 0.28 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 16 49 011H 1 21 Repeat 0.20 54 26.5 0.18 31.0 20.2 0.85 -0.16 0.02 6100 0.000 6100. 0.000 6100 0.000 6100 0.000 2 17 12 011H 1 20 Repeat 0.18 32 19.2 0.18 32.0 19.2 0.70 0.11 0.29 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 17 12 011H 2 20 Repeatl 0.16 27 14.9 0.16 20.0 11.0 0.39 -0.15 0.01 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 17 12 0111 3 20 New I_ _ 0.06 32 17.7 0.06 32.0 17.7 0.24 -0.40 -0.34 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2-14

Enclosure 2 PG&E Letter DCL-05-024 Table 5 - 2R11 PWSCC ARC Summary of Analysis Results UnaNDE jse Adjusted NDE CM Westinghouse Model OA ANL-TW Model

-- _ _ - - -- Total TotalToa Crc alNwor21 Pu ent D DLnghMFASa Burst FS entLength FS Burst FS Length Lnt SG Rw Cl TP r 211 Plg LngthMD ewCackCal D Lngt MDAD Fromom To PesPressu kaerBrsLeakageresurBurstge uPressugt SGRwClTP No Num Repeat Reason (in.) (%()(in.) (%) (%) Volt psi gpm PressLekg Leaag psi gpm PressLekg re Leaag Burs Leaka8Mge

_ _ _ ___ _ _ psi gpm __ _ _psi gpm 2 18 10 011H 1 25 New 0.13 33 20.8 0.13 28.0 17.7 0.41 -0.31 -0.18 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 19 15 01 1 1 20 Repea 0.13 32 18.0 0.09 20.0 11.8 0.45 0.00 0.09 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 19 17 01H 1 20 Repea >40% DOP 0.26 61 47.4 0.17 58.0 43.1 1.12 -0.51 -0.34 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 19 17 01H 2 20 Repea >40% DOP 0.12 52 37.5 0.12 49.0 35.3 0.74 -0.26 -0.14 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 21 35 02H 1 20 Repea . 0.21 35 23.0 0.21 29.0 19.0 0.47 -0.16 0.05 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 21 40 01H 1 21 Repea 0.13 33 20.0 0.13 31.0 18.8 0.53 -0.26 -0.13 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 21 41 011H 1 21 Repeat. 0.16 33 24.0 0.16 31.0 22.5 0.58 0.17 0.33 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 22 44 04H 1 21 Repea 0.16 36 23.3 0.16 28.0 18.1 0.30 -0.32 -0.16 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 22 55 01 H 1 21 Repea 0.16 33 22.4 0.16 33.0 22.4 0.401 0.09 0.25 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 23 14 011H 1 24 New 0.11 44 29.8 0.11 38.0 25.7 0.47 0.45 0.56 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 25 44 05H 1 21 Repea 0.44 33 20.1 0.27 20.0 11.7 0.52 -0.11 0.16 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 30 19 011H 1 33 New >40% DOP 0.24 66 38.9 0.18 63.0 35.7 1.08 -0.52 -0.34 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 30 19 011H 2 33 New >40% DOP 0.13 33 26.0 0.13 33.0 26.0 0.49 -0.16 -0.03 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 30 19 011H 3 33 New >40% DOP 0.11 36 22.9 0.08 26.5 19.2 0.41 0.41 0.49 6100 0.000 6100 0.000 6100 0.000 6100 0.000 2 34 38 011H 1 20 Repeat >40% DOP 0.17 55 42.7 0.17 55.0 42.7 1.35 0.27 0.44 6100 0.000 6100 0.000 6100 0.000 6100 0.000 3 15 47 02H 1 67 New 0.09 54 30.8 0.09 26.0 14.8 0.22 -0.15 40.06 6100 0.000 6100 0.000 6100 0.000 6100 0.000 3 21 78 03H 1 28 Repeat 0.36 43 32.8 0.32 35.5 26.2 1.00 -0.29 0.03 6100 0.000 6100 0.000 6100 0.000 6100 0.000 3 29 41 03H 1 28 Repeat 0.11 77 33.4 0.07 28.0 17.4 0.48 -0.08 -0.01 6100 0.000 6100 0.000 6100 0.000 6100 0.000 3 45 56 011H 1 28 Repeat 0.12 64 32.8 0.08 28.0 19.1 0.51 0.16 0.24 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 3 12 03H 1 19 Repeat_ 0.18 67 44.6 0.16 49.0 33.5 0.97 -0.09 0.07 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 5 15 011H 1 19 Repeat 0.13 49 32.9 0.06 28.0 17.8 0.38 -0.05 0.01 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 6 38 03H 1 19 Repeat >40% DOP 0.17 87 45.7 0.14 46.0 32.6 0.73 0.36 0.50 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 8 20 011H 1 58 New 0.41 58 29.9 0.37 43.0 27.6 1.10 -0.28 0.09 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 12 17 03H1 1 19 Repeat 0.14 49 32.2 0.12 31.0 21.2 0.88 .0.15 0.27 6100 0.000 6100 0.000 6100 0.000 6100 0.000 4 14 53 03H1 1 19 Repeat 0.18 97 43.0 0.18 49.0 26.4 0.41 -0.07 0.11 6100 0.000 6100 0.000 6100 0.000 6100 0.000 Note: DOP means depth outside plate (TSP). SG 2-2 R19C17 1H crack 2 and SG 2-2 R30C19 IH cracks 2 and 3 are plugged because crack I at same TSP is greater than 40% depth outside the TSP.

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Enclosure 2 PG&E Letter DCL-05-024 Table 6 2R12 Circumferential Indications at Dented Tube Support Plates r .7 Unadjusted NDE Adjusted NDE Adjusted for Upper Growth Rate per 95% NDE Uncertainty EFPY Circ Flaw MixedStblz Dent A Max Avg Max Avg Max Avg Max Avg SG lRowCol Crack TSP lType Volt Mode StVbilize Volt Angle Depth Depth Angle Depth Depth Angle Depth Depth Angle Depth Depth 22 5 33 1 1H ID 0.51 Yes Yes 20.74 23.2 38.0 28.4 23.2 40.0 26.3 77.0 64.2 43.7 NDD in lookup 22 18 27 1 11H OD 0.24 Yes 21.00 32.0 40.0 23.8 32.0 40.0 31.6 173.7 64.3 51.2 4.3 0.0 0.9 24 16 12 1 3H ID 0.38 = 1 1 11.60 27.4 84.0 42.1 27.4 46.0 26.6 81.3 68.6 44.0 2.4 1 3.9 1 2.9 Note 1: SG 2-2 R5C33 1H has axial PWSCC and circumferential PWSCC at the same TSP intersection (PWSCC mixed mode).

Note 2: Growth rate is based on adjusted NDE, not adjusted for upper 95% NDE uncertainty.

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Enclosure 2 PG&E Letter DCL-05-024 Figure 1 Circumferential Average Depth Trending 70 -_

60 - U 50 -

0 I

• 40 -

0 0

I I . a 30 a * *I- I UI 10 U 4-

• *UU

• I U,

20 I I I 10 -

0-1994 1995 1996 1997 . 1998 ,1999 2000 2001 2002 2003 2004 2005,

• Year Detected I a Average Depth - Linear Trend (Average Depth) I 2-17

Enclosure 2 PG&E Letter DCL-05-024 Figure 2 Circumferential Mixed Mode Average Depth Trending 60 50.

40 C

30 a20**

Eu 10I 0

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year Detected I a Circumferential Mixed Mode AD - Unear Trend (Circ Mixed Mode AD) 2-18

Enclosure 2 PG&E Letter DCL-05-024 Figure 3 Cumulative Number of Circumferential Indications 100 90 95I 80 E 70 2u 60 50 U-

.0-40 30 E 20 10 0

1995 1996 1997 1998 1999 . 2000 2001 2002 2003 2004 Year Detected I -- Number of circ indications 2-19

PG&E Letter DCL-05-024 Enclosure 3 Framatome ANP, Inc., an AREVA and Siemens company DCPP Unit 2 Voltage-Based ARC 90-Day Report Document Identifier 86- 5059194 - 00 2