ML052020002
| ML052020002 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/17/2005 |
| From: | Mahesh Chawla NRC/NRR/DLPM/LPD3 |
| To: | |
| Chawla M, NRR/DLPM, 415-8371 | |
| Shared Package | |
| ML052010097 | List: |
| References | |
| Download: ML052020002 (21) | |
Text
Prairie Island Unit 2R23 Outage*
NRC Category C-3 Phone Call and NRC Discussion Points May 17, 2005
- The attached information has not been validated. In many cases, it is preliminary information from ongoing inspection activities. To our knowledge, it is the best information available as of 6 PM on the date prior to this report and may be changed following further inspection, review, and analysis.
Participants
- Richard Pearson (alternate SG Engineer)
- Jim Begley (Framatome CMOA analyst)
- Jeff Kivi (PI Licensing)
- Terry Silverberg (PI Director of Engineering)
- Scott McCall (PI Engineering Programs Manager)
- Tom Downing (PI Engineering Programs Supervisor)
Current Status of 2R23 ISI SG Inspection (As of 1800 on May 16, 2005)
Category 21 SG 22 SG Acquisition 100 100
(% completed)
Analysis 100 100
(% completed)
- of Pluggable 6 8 Tubes
- Reroll 185 142 Candidates
Q1: Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.
ØLeak rates based on Tritium have trended from 0.5 to 0.8 GPD over the last cycle.
ØLeak rates based on Argon have been constant at 0.8 GPD over the last cycle.
ØLeak rates based on Xenon have been constant (or less than detectable) at 1.0 GPD over the last cycle.
Q2: Discuss whether any secondary side pressure tests were performed during the outage and the associated results.
Ø Due to very low primary to secondary leakage, no pressure tests were done to look for tube leakage
Ø There are secondary side pressure tests scheduled after replacement of all the remaining Alloy 600 explosive plugs with Alloy 690 welded plugs
Ø The pressure test is not a code requirement but is based on external operating experience PI 2R23 SG NRC Phone Call 5
Q3: Discuss any exceptions taken to the industry guidelines.
ØNo exceptions will be taken from industry guidelines.
Q4: For each SG, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100 percent of the dents/dings greater than 5 volts and a 20 percent sample between 2 and 5 volts), and the expansion criteria. Also, discuss the extent of the rotating probe inspections performed in the portion of the tube below the expansion transition region (reference NRC Generic Letter 2004-01, Requirements for Steam Generator Tube Inspections).
Ø Prairie island 2R23 steam generator inspection plan is attached on the following sheet.
Inspection Plan SCOPE PROBE TYPE S/G 21 S/G 22 Full Length - Bobbin 100% 100%
R o w s 1 t h r o u g h 4 U -B e n d s MRPC 100% 100%
R o w s 5 t h r o u g h 8 Ž U -B e n d s MRPC 33% 33%
Hot Leg Tubesheets MRPC 100% 100%
Hot Leg Roll Plugs MRPC 25% 25%
Post In Situ Pressure Test MRPC 100% 100%
S u p p l e m e n t a l* MRPC 100% 100%
Plug Visual N/A 100% 100%
B a s e l i n e n e w R e -Rolls Bobbin/MRPC 100% 100%
- Except the bend portion of rows 1 through 4 u-bends.
- ADR, CUD, DEP, DNI, DNT 5.0, DRI, DSI, DTI, INR 1.5 volts at a tube support plate, MBM, MRI, NQI, PLP (Bound MRPC PLPs), PSI, Cold Leg Thinning 40% or < 40% and 1.5 volts.
Ž Expansion plan defined in plant procedure 2H25.1.
Note: Cold Leg Tubesheet MRPC Examination is conducted every other outage.
Q5: For each area examined (e.g., tube supports, dents/dings, sleeves, etc), provide a summary of the number of indications identified to-date of each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications at the expansion transition).
For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g.,
observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).
Analysis Status Analysis Status (percent completed) SG 21 SG 22 as of 1800 on May 16, 2005:
Hot Cold Hot Cold Tubesheet Crevice MRPC 100 N/A 100 N/A Bobbin 100 100 100 100 U-Bend MRPC 100 100 100 100 Plug MRPC 100 N/A 100 N/A Special Interest MRPC 100 100 100 100 PI 2R23 SG NRC Phone Call 10
SG 21 Analysis Results to Date Degradation Mode and Location # Volt Depth Length New TSP Cold Leg Thinning (volumetric) 97 1.70 44 0.46 N AVB Wear (volumetric) 21 2.41 40 N/A N Old AVB Wear (volumetric free span) 50 2.49 38 N/A N Expansion PWSCC (axial) 221 1.87 N/A 0.52 N Expansion PWSCC (circ) 1 0.75 N/A 122° N Crevice ODSCC (axial) 2 0.52 N/A 0.44 N Sludge Pile ODSCC (axial) 1 0.16 N/A 0.37 N U-bend ODSCC/PWSCC (axial/circ) 0/0 N/A N/A N/A N TSP ODSCC (axial) 0 N/A N/A N/A N/A Dent ODSCC (axial/circ) 0/0 N/A N/A N/A N/A Dent PWSCC (axial/circ) 0/0 N/A N/A N/A N/A Plug ODSCC/PWSCC 0/0 N/A N/A N/A N/A Structural and accident induced leakage integrity was maintained during the previous cycle PI 2R23 SG NRC Phone Call 11
SG 22 Analysis Results to Date Degradation Mode and Location # Volt Depth Length New TSP Cold Leg Thinning (volumetric) 140 0.69 44 0.46 N AVB Wear (volumetric) 31 1.96 34 N/A N Old AVB Wear (volumetric free span) 33 2.38 38 N/A N Expansion PWSCC (axial) 145 3.53 N/A 0.94 N Expansion PWSCC (circ) 2 0.65 N/A 68° N Crevice ODSCC (axial) 3 0.15 N/A 0.53 N Sludge Pile ODSCC (axial) 2 0.11 N/A 0.32 N U-bend ODSCC/PWSCC (axial/circ) 0/0 N/A N/A N/A N TSP ODSCC (axial) 0 N/A N/A N/A N/A Dent ODSCC (axial/circ) 0/0 N/A N/A N/A N/A Dent PWSCC (axial/circ) 0/0 N/A N/A N/A N/A Plug ODSCC/PWSCC 0/0 N/A N/A N/A N/A Structural and accident induced leakage integrity was maintained during the previous cycle PI 2R23 SG NRC Phone Call 12
Q6: Describe repair/plugging plans.
Predicted Repairs SCOPE S/G 21 S/G 22 In Situ Pressure Test 5 5 AR1 - 6 Re-roll 155 87 AR2 - 8 Re-roll 40 14 ARE - Elevated Re-roll 14 0 Hot Leg Plug Removal 3 9 Cold Leg Plug Removal 3 15 Hot Leg Roll Plugs 10 18 Cold Leg Roll Plugs 10 18 Hot Leg Welded Plugs 3 9 Cold Leg Welded Plugs 3 15 PI 2R23 SG NRC Phone Call 13
Q6: Describe repair/plugging plans.
Required Repairs SCOPE S/G 21 S/G 22 In Situ Pressure Test 0 0 AR1 - 6 Re-roll 129 117 AR2 - 8 Re-roll 48 25 ARE - Elevated Re-roll 8 0 Hot Leg Explosive Plug Removal 3 9 Cold Leg Explosive Plug Removal 3 15 Hot Leg Roll Plugs 6 8 Cold Leg Roll Plugs 6 8 Hot Leg Welded Tubesheet Plugs 3 9 Cold Leg Welded Tubesheet Plugs 3 15 PI 2R23 SG NRC Phone Call 14
Q7: Describe in-situ pressure test and tube pull plans and results (as applicable and if available).
ØWe have no plans to pull tubes for unit 2, as part of a licensed repair program. We have, however, contracted a vendor to be mobilized for a tube pull should an inspection finding require one.
Ø Status - No tube pull needed .
ØWe are planning on performing up to 10 in situ tests.
Ø Status - No in situ needed .
Q8: Provide the schedule for steam generator-related activities during the remainder of the current outage.
ØET examinations were completed on May 16.
ØIn-situ testing is not required
ØRepairs should be completed by May 22
ØScheduled to install primary manways May 23
ØOutage schedule will be provided upon request PI 2R23 SG NRC Phone Call 16
Q9: Discuss the following regarding loose parts: 1) what inspections are performed to detect loose parts, 2) a description of any loose parts detected and their location within the SG, 3) if the loose parts were removed from the SG, 4) indications of tube damage associated with the loose parts, 5) the source or nature of the loose parts, if known PI 2R23 SG NRC Phone Call 17
using manual analysis by primary.
B) Secondary uses Computer Data Screening (CDS) with a PLP specific sort from TSH + 0.3 to 07H + 1.00 and from TSC + 0.3 to 07C + 1.00 and various wear detection sorts from TSH - 1.0 to TSC - 1.0.
C) The bobbin examination on peripheral and open lane tubes, 4 rows and columns deep are examined in a separate group which is identified as such to the analyst for heightened analysis awareness for PLPs.
D) All MRPC data is evaluated for PLPs.
E) All bobbin PLP indications are tested with MRPC.
F) All PLP indications are bounded radially by one tube at the same elevation.
G) A Foreign Object Search and Retrieval Inspection (FOSAR) is completed on the secondary side of one SG (21 this outage) on top of the tubesheet using fiberscope equipment every outage with a contingency plan to inspect the other SG based on eddy current results.
H) Any PLP that cannot be resolved with ECT are inspected from the secondary side for resolution.
- 2. A) SG 21 has 9 MRPC PLP indications on the top of the hot leg tube sheet.
B) SG 22 has 14 MRPC PLP indications on the top of the hot leg tube sheet.
- 3. A) SG 21 secondary side FOSAR is scheduled following sludge lancing on May 18.
B) SG 22 secondary side FOSAR is complete.
- 4. A) SG 21 has no indication of wear associated with PLPs.
B) SG 22 has no indication of wear associated with PLPs .
- 5. A) SG 21 PLP indications are most likely sludge rocks based on historical lookups. Visual confirmation will be conducted with the FOSAR inspection.
B) SG 22 PLPs - 8 indications are most likely sludge rocks based on historical lookups dating back to 1995 and 6 indications are from weld slag, machine remnants and sludge rocks.
See PLP Tables (next two slides)
SG 21 PLPs Row Col Location Wear History Removed Source 29 24 TSH +0.03 to +0.20 No Yes - 2003 ? ?
39 30 TSH +0.02 to +0.31 No Yes - 2003 ? ?
38 31 TSH +0.05 to +0.25 No Yes - 2003 ? ?
39 31 TSH +0.00 to +0.35 No Yes - 2003 ? ?
31 50 TSH +0.05 to +0.25 No Yes - 1997 ? ?
32 50 TSH +0.09 to +0.45 No Yes - 2000 ? ?
32 51 TSH +0.12 to +0.50 No Yes - 2000 ? ?
6 64 TSH +0.02 to +0.24 No Yes - 2003 ? ?
7 64 TSH +0.00 to +0.23 No Yes - 2003 ? ?
SG 22 PLPs Row Col Location Wear History Removed Source 23 20 TSH +0.00 to +0.44 No Yes - 1995 No Unknown 24 20 TSH +0.06 to +0.54 No Yes - 1995 No Unknown 23 22 TSH +0.67 to +1.31 No Yes - 1995 No Unknown 23 23 TSH +0.65 to +0.94 No Yes - 1995 No Unknown 26 42 TSH +0.08 to +0.29 No No Yes Weld Slag 30 45 TSH +0.14 to +0.45 No Yes - 1995 No Unknown 31 46 TSH +0.10 to +0.33 No Yes - 1995 No Unknown 32 47 TSH +0.45 to +0.70 No Yes - 1995 No Unknown 33 47 TSH +0.13 to +0.35 No Yes - 1995 No Unknown 37 59 TSH +0.15 to +0.38 No No No Scale 5 73 TSH -0.02 to +0.29 No No Yes Machine Remnant 6 73 TSH +0.08 to +0.39 No No Yes Machine Remnant 7 73 TSH +0.08 to +0.42 No No Yes Sludge Rock 8 73 TSH +0.00 to +0.40 No No Yes Sludge Rock PI 2R23 SG NRC Phone Call 21