ML022670422
| ML022670422 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 09/23/2002 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML022670422 (4) | |
Text
2/15/02 SIG Conference Call Discussion Points existed in this unit prior to
- 1) Discuss whether any primary-to-secondary leakage shutdown.
the operating cycle.
No primary to secondary leakage was reported during tests.
- 2) Discuss the results of secondary-side hydrostatic None performed.
areas examined, including the
- 3) For each SG, provide a general description of in each area.
expansion criteria utilized and type of probe used I and 2 U-bend region), no expansion Bobbin: 100% full length testing (except Row criteria since initial inspection is 100%.
to 3" below tubesheet. No expansion
+Pt: 100% hot leg top of tubesheet from 6'"above is 100%. If a C-3 condition for the top criteria for hot leg since initial inspection program 20% cold leg program will be included at of tubesheet is reported for the 2R09 outage, a 2R10.
indications at tube support plate
+Pt: 100% examination of bobbin distorted signal distorted signal indications, 100%
intersections, 100% examination of bobbin freespan phase.
bobbin mixed residual signals >1.5 volts, and < 50' U-bends. Expansion criteria is
+Pt: 100% examination of Row 1 and 2 small radius 20% of Row 3 if an indication is reported in Row 2.
+Pt: 20% examination of hot leg Alloy 690 roll plugs.
determine if ODSCC is hidden by wear
+Pt: 20% examination of AVB wear locations to scar signal.
+Pt: 20% examination of hot leg freespan dings >5V indications (those not
- 4) For analyzed eddy current results, describe bobbin Point/Cecco examined with rotating pancake coil (RPC)) and RPC/Plus indications. Include the following information in the discussion: location, of number, degradation mode, disposition, and voltages/depths/lengths significant indications.
only to AVB wear and MBMs with Bobbin indications not examined by +Pt are applicable no change from history.
Bobbin Inspections:
AVB Wear in service is 35%. Number of A None > 40%TW. Maximum AVB wear depth left AVB wear indications is essentially the same as 2R08.
Distorted Support Plate Indications 0 316 indications, slight increase over 2R08 results (279)
RPC Inspections:
Hot Leg TTS 0 SG A: 6 tubes with OD circumferential degradation, 8 tubes with OD axial crack-like, loose part wear) degradation. 1 tube with volumetric degradation (not with OD axial a SG B: 3 tubes with OD circumferential degradation, 1 tubes (not crack-like, loose part wear) degradation, 1 tube with volumetric degradation with ID axial a SG C: 2 tubes with OD circumferential degradation, 1 tube degradation for all 3 SGs with TTS 0 20 tubes total for all 3 SGs with TTS ODSCC, 1 tube PWSCC maximum sludge pile a Largest sludge pile axial ODSCC +Pt amplitude: 0.27 volts, axial ODSCC depth: 63%, maximum length: 0.25" 0.28 volts,
- Largest top of tubesheet circumferential ODSCC +Pt amplitude: arc depth: 63%, maximum maximum top of tubesheet circumferential ODSCC length: 116 degrees volts, maximum depth:
0 Single top of tubesheet axial PWSCC +Pt amplitude: 0.72 53%, lengt h: 0.12" Small Radius U-bends of all Row 1 and 0 No degradation reported; mid-range +Pt inspection performed with noise values exceeded Row 2 tubes, high frequency +Pt performed for tubes predetermined limit (4 tubes) also reported
& Three tubes preventively repaired due to probe restriction (difficulty in 2R08) at 02H, 03H, and 04H (20%
Hot Leg Dents > 5 Volts, > 2 Volts but less than 5 Volts sample)
" All bowbin DSI signals +Pt inspected, 4 indications confirmed as axial in all 3 angles _<500, and > 1.5 volts
"* All mixed residual bobbin signals with phase PWSCC.
SGs +Pt inspected. One confirmed indication as axial Hot Leg Freespan Dings >5V (20% sample) expanded to all HL
- 5) Describe repair/plugging plans for the SG tubes that meet the repair/plugging criteria.
small radius U All crack-like indications at the top of tubesheet, TSP intersections, the voltage based While bends, and freespan are repaired by plugging upon detection.has not been implemented.
repair criteria per GL 95-05 is licensed for Unit 2, the criteria results, including any "look
- 6) Discuss the previous history of SG tube inspection backs" performed.
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been ODSCC at the top of tubesheet The dominant plugging contribution for Unit 2 has tubes have been plugged for of 49 region. Through the 2R08 inspection, a total for axial ODSCC, amongst all 3 SGs. Past history reviews circumferential ODSCC, 50 indications at the top of tubesheet have concluded that some percentage of reported are low.
have precursor signals. Thus, ODSCC growth rates
- 7) Discuss, in general. the new inspection findings.
at the 2R09 outage.
For the first time, axial PWSCC was reported at the top of tubesheet. The indication was A single indication was reported in SG C expansion transition. Shotpeening was located within the geometry of the hardroll of the BVPS Unit 2 SGs, prior to operation.
applied to the hardroll expansion transitions initiation potential. Other similar SGs that This has successfully reduced axial PWSCC for this location have experienced significant did not perform an ameliorative measure axial PWSCC initiation.
SG were reported. The first was reported in Two indications suggestive of axial PWSCC baffle). The second was reported in B at the 05H TSP (4"f TSP above flow distribution reported by bobbin and confirmed by +Pt.
were SG C at the 04H TSP. These indications been +Pt tested. No additional confirmed All similar bobbin indications in all SGs have indications have been reported.
the 2R09 outage.
For the first time, ding ODSCC was reported at in a 14 volt ding. The ding is located between A single indication was reported in SG A is being expanded to all hot leg dings >5V.
the 02H and 03H TSPs. +Pt tested program if applicable.
- 8) Discuss your use or reliance on the X-probe, The X-probe is not being used at the 2R09 outage.
if applicable and available,
- 9) Describe in-situ pressure test plans and results, including tube selection criteria.
be in situ pressure tested. The EPRI in Indications that exceed screening criteria will screening indications. To date, no situ pressure testing guidelines are used for indications have exceeded the screening criteria.
results, if applicable and available;
- 10) Describe tube pull plans and preliminary include tube selection criteria.
No tubes are scheduled to be pulled.
previous operating cycle.
- 11) Discuss the assessment of tube integrity for the cycle followed a methodology consistent with Tube integrity assessment for the previous were judged to represent a leakage the EPRI tube integrity guideline. No indications Page 3 of 4
to represent a challenge to structural condition at SLB; no indications were judged integrity performance criteria.
next operating cycle.
- 12) Discuss the assessment of tube integrity for the cycle will follow a methodology Assessment of tube integrity for the next operating consistent with the EPRI tube integrity guideline.
during the remainder of the current
- 13) Provide the schedule for SG-related activities outage.
to be completed on 2/14/02.
Eddy current testing and evaluation is scheduled taken, in response to lessons
- 14) Discuss what steps have been taken, or will be In addition, please be prepared learned from the Indian Point Unit 2 tube failure.
to discuss the following:
to identifying a new a) Discuss the actions that are taken in response degradation mechanism, and levels are acceptable, b) Discuss the actions taken to ensure that data noise and for criteria to address data c) Address data quality issues and the need quality.
will utilize available inspection a) Identification of new degradation mechanisms If necessary, in situ techniques to adequately characterize the degradation.
tube structural and leakage pressure testing will be performed to establish via Station Corrective Action integrity. New degradation mechanism tracked Program.
the outage using the 2R08 eddy b) Tube noise levels were evaluated prior to using the Westinghouse current data. Tube noise levels were evaluated against noise levels of tubes in the guideline, which compares plant noise levels comparison of plant noise levels EPRI ETSS database, as well as a theoretical degradation depths that could against flaw amplitudes that represent maximum at the end of the next operating be left in service and still satisfy tube integrity for each small radius U-bend cycle. Noise measurements are being recorded exhibiting noise va!-es exceeded test using the mid-range +Pt coil. Those tubes a high frequency +Pt coil.
a previously established limit are tested with on line. A qualified data analyst, c) Data quality during the outage is monitored quality during the acquisition phase.
referred to as the "data cop", monitors data Data judged to be noisy is rejected at this point.
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