ML14125A145
| ML14125A145 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/01/2014 |
| From: | Mccreary M FirstEnergy Nuclear Generation Corp |
| To: | Jeffrey Whited Plant Licensing Branch 1 |
| Whited J, NRR/DORL/LPLI-2 | |
| References | |
| Download: ML14125A145 (7) | |
Text
Whited, Jeffrey From: McCreary, Dave M <dmccreary@firstenergycorp.com>
Sent: Thursday, May 01, 2014 11:37 AM To: Whited, Jeffrey Cc: Lashley, Phil H.
Subject:
RE: FW: Unit 2 Steam Generator Tube Inspection Conference Call Attachments: NRC Phone Call Responses 2R17.doc
- Jeff, In support of our Beaver Valley Unit 2 steam generator inspection phone call this afternoon, please see the attached FENOC responses to the NRCs questions.
Thank you, Dave From: Whited, Jeffrey [1]
Sent: Tuesday, April 29, 2014 7:42 AM To: Lashley, Phil H.
Subject:
Unit 2 Steam Generator Tube Inspection Conference Call
- Phil, The NRC staff can support a conference call on Thursday, May 1, at 3pm.
Please let me know if FENOC is available during that time.
- Thanks, Jeffrey Whited Project ManagerBeaver Valley, Susquehanna, and TMI NRC/NRR/DORL/LPL I2 (301)4154090 jeffrey.whited@nrc.gov The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message.
1
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections
- 1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.
FENOC Response: No primary-to-secondary leakage was experienced during Cycle 17.
- 2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.
FENOC Response: No secondary side pressure tests were performed during 2R17.
- 3. Discuss any exceptions taken to the industry guidelines.
FENOC Response: No exceptions taken to industry guidelines.
- 4. 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 dings/dents greater than 5 volts and a 20% sample between 2 and 5 volts) and the expansion criteria.
FENOC Response:
The following applies to all SGs unless specifically noted.
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections Location Probe Initial Expansion Scope Examined Scope Base Scope Programs Full Length Bobbin 100% None (720)
Hot Leg Tubesheet Plus Point 100% 20% cold leg if structural or leakage significant (TSH +6, -3) indication detected Dents >5V Plus Point 100% None TSPs with Bobbin Plus Point 100% >2V None (consistent with GL 95-05) For growth DSI trending purposes, all 2R16 DSIs confirmed to contain axial ODSCC were inspected with +Pt.
TSPs with Bobbin Plus Point 100% ** None DNI TSPs with SPR Plus Point 100% ** None
>2V Dings >1V Plus Point 100% None Row 1 and 2 U- Plus Point 100% 100% Row 3 if Row 2 indication detected bends Sleeves Plus Point 100% None Hot Leg tube Bobbin 100% None above sleeve (630)
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections Location Probe Initial Expansion Scope Examined Scope Special Interest SGB Cold Leg Plus Point 20% 100% SGB, 20% other SGs if SCC detected Tubesheet (TSH
+6, -3)
- TSPs with SPR Plus Point 25% None
>1.5V, <2V Dents >2V, <5V at Plus Point 100% 100% hot leg dents >2V for PWSCC detection 01H, 02H, 03H, 04H TSPs Dents within +/- 1 Plus Point 100% None inch of AVBs Row 3 thru 8 U- Plus Point 25% 100% Row 3 thru 10 bends Freespan bobbin Plus Point 100% None NQI, FSI, etc.
Hot Leg tubesheet Plus Point 100% None BLG/OXP below F* down to neutral axis New PLP and Plus Point 100% Continue boxing until PLPs are no longer historic locations including observed plugged due to 2-tube box PLP interaction Plugs Visual 100% None FOSAR Visual Tube lane, In-bundle visual of new PLPs by eddy current annulus Channelhead Visual 100% None bowl, stub runner to divider plate weld SGB, SGC steam Visual N/A None: expansion depends upon observations drum
- SGB cold leg TTS +Pt sampling was performed as SGB cold leg has not been sampled since 2R12. SGA cold leg has been sampled twice since 2R12 and SGC cold leg sampled at 2R16.
- Scope exceeds GL 95-05 requirements.
Eddy current testing is approximately 85% complete in SGA, 98% complete in SGB, and approximately 98% complete in SGC.
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections
- 5. For each area examined (e.g., tube supports, dents/dings, sleeves, etc.), provide a summary of the number of indications identified to date for each degradation mode (e.g., number of circumferential primary water stress-corrosion cracking (PWSCC) 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 PWSCC at the expansion transition for the first time at this unit).
FENOC Response:
A. Hot Leg TTS Expansion Transition and Sludge Pile:
SGA: 18 tubes affected, 14 with circumferential ODSCC, 4 with axial ODSCC SGB: 6 tubes affected, 5 with circumferential ODSCC, 1 with axial ODSCC SGC: 13 tubes affected, 10 with circumferential ODSCC, 3 with axial ODSCC Circumferential ODSCC:
Maximum 300 kHz +Pt voltage of 0.35V, maximum arc length of 321 degrees, realistic estimate of maximum depth of about 70%TW. Analysts are instructed to conservatively estimate flaw length during the resolution process to ensure that the most significant flaws are adequately evaluated.
Largest circumferential ODSCC PDA from profiling is 34%.
Axial ODSCC:
Maximum 300 kHz +Pt voltage of 0.39V, maximum length of 0.25 inch, maximum depth estimated using EPRI ETSS I28432 voltage based regression of 63%TW.
B. Hot Leg TSP:
SGA: 1932 total DSI (275), DNI (518), and SPR (1140) reports from bobbin coil analysis; 4 tubes confirmed to contain axial ODSCC.
SGB: 764 total DSI (394), DNI (173), and SPR (197) reports from bobbin coil analysis; 16 tubes confirmed to contain axial ODSCC.
SGC: 933 total DSI (332), DNI (287), and SPR (314) reports from bobbin coil analysis; 10 tubes confirmed to contain axial ODSCC.
Axial ODSCC:
Maximum 300 kHz +Pt voltage of 0.27V, maximum length of 0.51 inch, maximum depth estimated using EPRI ETSS I28432 voltage based regression of 56%TW.
C. AVB Wear:
47 indications in SGA, 98 in SGB, 2 in SGC. Maximum depth report is 43%TW in SGB and three tubes exceed tech spec plugging limit.
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections D. Loose Part Wear:
No loose part wear was reported.
E. Ding ODSCC:
792 DNGs in SGA, 790 in SGB and 600 in SGC. No ODSCC at dings has been reported to date.
- 6. Describe repair/plugging plans.
FENOC Response:
All crack-like indications at the top-of-tubesheet, U-bends, and freespan will be plugged.
Tube plugging due to axial ODSCC will follow the protocol of GL 95-05.
All PWSCC or circumferential ODSCC at TSP intersections will be plugged.
AVB wear >40%TW by bobbin will be plugged.
Historic volumetric indications associated with loose parts will be sized according to ETSS 21998.1 and left in service if depth <40%TW and no presence of a loose part is observed.
Tube sleeving is not planned for the 2R17 outage.
- 7. Describe in-situ pressure test and tube pull plans and results (if applicable and available).
FENOC Response:
To date, no tubes require in situ pressure testing.
- 8. Discuss the following regarding loose parts:
what inspections are performed to detect loose parts; a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known);
if the loose parts were removed from the SG; and indications of tube damage associated with the loose parts, as applicable.
FENOC Response:
Both eddy current and FOSAR is used to detect foreign objects.
To date, no new degradation associated with PLPs has been reported.
- 9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g.
in-bundle visual inspections, feed-ring inspections, sludge lancing, assessing deposit loading, etc.)
FENOC Response:
Sludge lancing was performed in all SGs; removal totals were 62.5 lb in SGA, 62.0 lb in SGB, 55.5 lb in SGC. Increase of 33.5 lbs (total) compared to 2R16.
FENOC Response to NRC's Questions Regarding 2R17 Steam Generator Inspections FOSAR of the tube lane and peripheral annulus was performed in all SGs. No metallic objects were observed. FENOC uses a two-pass FOSAR where the hot and cold leg TTS is inspected from each of the tubelane handholes. The probe is inserted around the circumference to the opposite blowdown pipe. The inspection is performed on the withdraw of the probe. This process is repeated for each handhole, thus, any areas which may not receive a thorough visual exam due to probe configuration, viewing angle, etc., are adequately inspected by the second pass, which views the location from the a different angle.
Visual inspection of the SGB and SGC steam drum is planned. This inspection will include the feedring OD, feedring ID at J-nozzle entrance, and other high flow velocity regions of the upper steam drum. UT thickness measurements of the feedring at various locations around the ring are planned.
- 10. Discuss any unexpected or unusual results.
FENOC Response:
The TTS ODSCC results with regard to number of affected tubes is reduced compared to the projected value. This observation is not atypical as the historic trending of ODSCC observations at the TTS has shown the likelihood that the indication count can increase from one outage to the next is equal to the likelihood that the indication count will decrease.
- 11. Provide the schedule for SG-related activities during the remainder of the current outage.
FENOC Response:
Complete inspection and plugging in all SGs. Closeout of all primary and secondary side inspection programs.