ML13129A024
| ML13129A024 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/30/2012 |
| From: | Ruz P Plant Licensing Branch 1 |
| To: | Ganesh Cheruvenki NRC/NRR/DE/EVIB |
| References | |
| FOIA/PA-2013-0030 | |
| Download: ML13129A024 (19) | |
Text
Cheruvenki, Gahesh From: Guzman, Richard 1A i.. ._.
Sent: Wednesday, May 30,2 PM To: Cheruvenki, Ganesh
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
Ganesh -the original information request was sent electronically to VY on 1/30/12 (ML12146A107). The teleconference was on 2/8/12.
From:m Cheruvenki, Ganesh Sent: Thursday, May 24, 2012 1:42 PM To: Guzman, Richard
Subject:
FW: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
Here is one of e-mails you should look into.
From: Kim, James \f Sent: Monday, February 27, 2012 8:45 AM To: Cheruvenki, Ganesh Cc: Basavaraju, Chakrapani; Jessup, William; Scarbrough, Thomas; Sheng, Simon
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
Gentlemen, VY has provided the final counts for GE reports INRs regarding the steam dryer inspections.
There are 3 RF024 evaluations, 1 RF025 evaluation, 2 RF026 evaluations, 1 RF027 evaluation and 1 RF028 evaluation to make 8 in all.
There are 4 INR's from GE for RF024, 7 INF's from AREVA for RF025, 17 INR's from GE for RF026, 24 INR's from AREVA for RF027, 23 INR's from AREVA for RF028 and 1 INR from GE for RF029. These INR's and INF's from GE and AREVA are just for the steam dryer and note that there are sometimes more than one indication per INR or INF.
Thanks Jim Kim From: Cheruvenki, Ganesh Sent: Thursday, February 23, 2012 2:23 PM To: Kim, James Cc: Basavaraju, Chakrapani; Jessup, William; Scarbrough, Thomas; Sheng, Simon
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
- Jim, Please inform the licensee that disposition of the detected flaws is critical for our review. If Simon is not satisfied, we may have to reject the request.
From: Sheng, Simonk cI 2 Sent: Thursday, February 23, 2012 2:09 PM To: Cheruvenki, Ganesh Cc: Kim, James; Basavaraju, Chakrapani; Jessup, William; Scarbrough, Thomas
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
1 R1l7o
- Ganesh, I am more interested in reports documenting disposition of the detected flaws. Do these 20 or so inspection reports also contain information regarding disposition of the detected flaws? Or GE has separate reports to document the disposition?
Simon From: Cheruvenki, Ganesh Sent: Thursday, February 23, 2012 1:48 PM To: Kim, James; Basavaraju, Chakrapani; Scarbrough, Thomas; Jessup, William; Sheng, Simon
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
It is OK with me. At least Pani/Tom and Simon should be present.
From: Kim, James Sent: Thursday, February 23, 2012 10:32 AM To: Cheruvenki, Ganesh; Basavaraju, Chakrapani; Scarbrough, Thomas; Jessup, William; Sheng, Simon
Subject:
RE: Inspections--Steam dryer--Today's meeting at 1.00 pm at O9B6.
Gentlemen, VY has proposed that both GE and VY representatives are willing to bring the inspections reports (approx. 20 GE proprietary inspection reports) to NRC for tech staff to review the steam dryer inspection reports and answer any questions NRC tech staff may have. Please let me know if this approach is acceptable.
Thanks Jim Kim From: Cheruvenki, Ganesh Sent: Tuesday, February 21, 2012 8:59 AM To: Basavaraju, Chakrapani; Scarbrough, Thomas; Jessup, William; Sheng, Simon Cc: Kim, James
Subject:
Inspections--Steam dryer--Today's meeting at 1.00 pm at 09B6.
Importance: High Pani, Tom, Simon and Billy Here is my draft report on the inspection results (RF-26, 27 and 28) of the steam dryer and it contains status of new indications. I still think we need to see the GE evaluation report which can provide information on the licensee's justification for using less frequent inspections.
2
The inspections that were conducted during RFO 26, 27 and 28 include areas that were newly modified during RFO-24.
Inspections-RFO Number of new Location of the Possible aging Remarks indications indications degradation Total---29 19 indications were IGSCC-cold work Confirm whether on vertical guides at Type of 304 that was stress relieving 1750, and one used in RFO-24-L or treatment was indication at 2150, non-L grade? performed after The indications are welding. All these perpendicular to Some indications-- indications that were vertical guide channel fatigue characterized are welds-IGSCC; 3 definitely cracks-indications at the depth is unknown-Steam dam support at fracture mechanics 350 -2004 cannot be used.
modification with new Qualitative judgment welds cold work- -very arbitrary and IGSCC; 5 indications nebulous at lifting rods and dryer screws -fatigue; 1 indication-dryer vane-IGSCC.
Note-No justification-(a) crack is self arresting, (2) flaw tolerance; (3) stresses due to welding/grinding; (4) no quantitative analysis
-(5) further inspections during RF27/RF 28-did not monitor these indications-no length of the indications recorded. - to justify lower inspection frequency-PROVIDE technical basis.
Inspections-RFO Number of new Location of the Possible aging Remarks indications indications degradation Total---18 2 indications were on IGSCC-cold work Confirm whether vertical guides at 3240 Type of 304 that was stress relieving and 4 indications on used in RFO-24-L or treatment was dryer rods at 2150 and non-L grade? performed after 324 0-possible welding. These new fatigue? The indications are indications are located at areas that perpendicular to are different from vertical guide channel those identified in welds-IGSCC; 3 RFO-26 and RFO-indications at the High stress/low Steam dam support at stress-COLD 350 -2004 WORK?
modification with new welds cold work-IGSCC; 2 indications-dryer drain channel vertical weld-IGSCC.
Draft Response to Supplemental Information Request By letter dated December 22, 2011 (Entergy letter BVY 11-085), Entergy submitted a proposed license condition change. This change requested a steam dryer re-inspection frequency in accordance with the interval specified in BWRVIP-139-A at every seven refueling outages based on an 18 month cycle. The NRC requested supplemental information to support the December 22, 2011 submittal.
The information contained in this document serves to provide the supplemental information requested by the NRC. It also serves to determine an alternate proposed steam dryer re-inspection frequency in accordance with section 5.3.4 of BWRVIP-139-A, and addresses questions provided by the NRC. This response encapsulates the following information which is derived from the RF024 steam dryer pre-emptive modifications, compliance with industry inspection recommendations and inspection history and assessments prior to and post Extended Power Uprate (EPU). EPU was implemented prior to RF026.
- 1. Steam Dryer Pre-emptive Modifications Vermont Yankee Nuclear Power Station (VY) performed modifications to the Steam Dryer to preclude the failures experienced at EPU conditions in other BWR-3 steam dryers. These failures at other BWR's comprised of through-wall cracking in the outer bank hood on the 900 andthe 2700 side. At these other plants several internal braces were detached and found on top of the steam separators.
The failure was accompanied by a significant increase in moisture content. The cause of the failure was attributed to high cycle fatigue resulting from low frequency oscillating pressure loads (< 50 Hz) of higher amplitude at Extended Power Uprate (EPU) operation and the local stress concentration introduced by the internal brackets that anchor the diagonal internal braces to the dryer hoods.
Based on the lessons learned from these failures, VY performed the modifications listed below and developed a'plant specific finite element analysis to qualify the steam dryer for 120% EPU operating conditions (
Reference:
NRC SER for EPU, Letter NVY 06-028, dated March 2, 2006). The VY stress analysis showed the weld at thetop of the outer vertical plate with the most limiting stress to be considerably lower than the ASME fatigue limit stress at VY of 13,600 psi
(
Reference:
Entergy Letter BVY 06-056 to NRC, dated June 30, 2006). As seen below, the existing '2-inch vertical plates were replaced with 1-inch thick plates.
In addition to the planned modifications, several repairs were performed based on the findings of the exterior IVVI inspections. All new hardware was fabricated from ASME SA-240/ASTM A240, Type 304L and 316L austenitic stainless steel material and welded with Type 308L filler material for shop welds and Type E316-17 and E316-16 for the underwater welding. The steam dryer modifications and repairs consisted of the following:
- Cutting out the existing 1/2-inch vertical and horizontal plates on each of the two Outer Hoods and replacing with 1-inch thick plates. The vertical Page 1 I
plate was fabricated with three shop welded gusset sections. This design minimized the amount of underwater welding at the site, reducing the amount of vertical welding by approximately 300 inches.
- Removing the four diagonal braces inside the Outer Hoods.
- Replacing the 1/4-inchthick horizontal cover plates that are adjacent to the steam outlet nozzles. The new cover plates are 5/8-inch thick.
" Removing the old Tie-Bars and installing eight mitigation Tie-Bars along with support gussets on the outer Tie-Bars.
" Installing reinforcement hardware in the areas behind the lifting lugs near the outer plenum vertical welds. The new hardware will distribute the loading in the areas where the V-02-90 and V-02-270 cracks were found to minimize the potential for future cracking.
" Repairing the crack indications at weld locations V-02-90 and V-02-270.
" Adding new tack welds to the four leveling screws.
The combined effect of these modifications resulted in:
" Lowering of actual stresses through a more uniform load distribution.
" Increased the structural integrity of the steam dryer.
" The replaced hardware material is less susceptible to IGSCC.
" Minimized the potential for the generation of loose parts.
- 2. Compliance with Industry Inspection Recommendations VY has completed three full scope steam dryer examinations post EPU, with no signs of crack growth activity and no cracking in the replaced hardware. These Examinations were in RF026 (2007), RF027 (2008) and RF028 (2010). In RF029 (2011), VY also inspected the drain channel weld crack indications with "No discernible changes were noted this outage to these indications" (
Reference:
jINR-r-VI-VYR29-1 1-01 Steam Dryer). The drain channel crack indication in
!_4DC-X4&is the limiting flaw in the steam dryer; also with no signs of crack 3 growth activity post EPU.
SIL 644, Revision 2 recommends inspection of susceptible locations during each EPU subsequent refueling outage. The recommendations include:
- Continue the inspections at each refueling outage until at least two full operating cycles at the final uprated power level have been achieved.
- Aftertwo full operating cycles at the final uprated power level, repeat the visual inspection of all susceptible locations of the steam dryer at least once every two refueling outages.
" For BWR/3-style steam dryers with internal braces in the outer hood, repeat the visual inspection of all susceptible locations of the steam dryer during every refueling outage.
- Note that VY has removed the internal braces as part of the pre-emptive modification in RF024.
Page 2
BWRVIP-139-A recommends a baseline inspection during the next scheduled refueling outage following an increase in power level of more than 2% above current licensed thermal power. The recommendations include:
" Cracks left in the "as found" condition shall be re-inspected at each subsequent scheduled refueling outage until it is demonstrated that the crack has stabilized.
" If there is no increase in power level from the current licensed power then the steam dryer shall be re-inspected, at a frequency not exceeding 5 (24 month) or 7 (18 month) refueling cycles.
- The scope of the inspection shall include all key locations as indicated in red in Figures 5-1 through 5-11 in BWRVIP-139-A and a 10% sampling of the other locations called out in the baseline inspection guidelines, as applicable to a square-hood dryer design.
VY has complied with both SIL 644 and BWRVIP-139 examination requirements and by completing three full scope steam dryer examinations has :exceeded the inspection frequency requirements post EPU recommended by these documents.
- 3. Steam Dryer Inspections and Assessments Post EPU VY has completed three full scope steam dryer examinations post EPU with no signs of crack growth activity and no cracking in the replaced hardware. These examinations were in RF026, RF027 and RF028. An additional examination was performed in RF029 to re-inspect previous indications in the area of the DC-V4C weld and to verify no crack growth.
Weld DC-V4C is the limiting flaw indication seen in the steam dryer. VY has examined this indication since RF024 (2004), and with improved examination equipment since RF027 (2008).
- The RF024 examination noted the indication in the drain channel DC-V4C weld "starting near the top of the weld and continuing down approximately 14.0 inches", although "The indication length was determined to be 11.89 inches" (
Reference:
INR-VYR24-04-04, Rev. 2). Considering a crack growth rate of 5x IOE-05 inch/hr (BWRVIP) and an initial length of 11.89 inch, the flaw indication should have grown to approximately 18.5 inch in length by RF029 using 13,140 hours0.00162 days <br />0.0389 hours <br />2.314815e-4 weeks <br />5.327e-5 months <br /> per each 18-month cycles, which is not the case.
The flaw indication in the DC-V4C weld measured 15 inches in RF027 with technological advanced tooling and the length has not changed in the last inspection in RF029 confirming lack of growth over several operating'cycles.
" The RF025 examination data sheet noted "No discernible change was noted".
" The RF026 examination noted "This examination shows no visual change associated with the indication" (
Reference:
INR-IVVI-VYR26-07-05, Rev. 1).
- The RF027 examination for DC-V4C weld showed "As the flaw extends all the way to the mid support ring and the lower stop point appears to be the same point it was in RF026, the total length of this flaw is estimated to be 15 inches". The evaluation of the DC-V4C flaw revealed three small areas in Page 3
which the indication could not be positively seen to travel through and join up with the clear indications above and below the areas. The evaluation measured the "gaps" as approximately 0.41 inches, 0.16 inches and 0.52 inches in length. Two additional linear indications were also identified in RF027. These are: (a) in the heat affected zone (HAZ) on the drain pipe DC-H-27 intersection with the drain channel. The indications at DCH-27 and at DC-V4C do not connect to each other. There is a gap of .91 inches between the indications and (b) in the drain pipe DC-H-33 side of weld DC-V4C
(
Reference:
INR-VYR27-05, Revision 2) (Note: The indication in the DC-H-33 weld was determined to be non-relevant in RF028).
- The RF028 examination of the DC-V4C weld noted "The vertical components and lower stop point of the indication was reviewed against the RF027 images and no discernible growth was observed". This examination identified the upper end point to turn and propagate intermittently along the lower HAZ of the drain channel to support ring weld (drain channel side) behind weld DC-H-27 to a stop point approximately adjacent to the support ring header block at 3550. This horizontal run of the indication was not seen during previous examinations of DC-V4C. The indication length is estimated to be 9.9 inches. The indication is on the internal drain channel and not connected to the external dryer skirt. This indication was pre-existing as was partially viewed in the background of the DC-H-26 examination of RF027.
The previously identified indication in the HAZ of the drain pipe DC-H-27 weld was also examined with no discernible changes from previous examinations. The indication in the drain pipe DC-H-33 side of weld DC-V4C previously reported in RF027 was determined to be non-relevant. The area was interrogated extensively at very high magnification and no indication can be found on the right hand side of weld DC-V4C (
Reference:
INR-VYR28-2 Rev. 2 and INR-VYR28-3, Rev. 2). Refer to attached Figure 1 for flaw indications in the area of drain channel weld DC-V4C.
- The RF029 examination included the flaw indications in the area of the DC-V4C weld seen in RF028, and "No discernible changes were noted this outage to these indications" (
Reference:
INR-IVVI-VYR29-1 1-01).
The flaw indications in the HAZ of drain channel weld DC-V4C have been examined in depth since RF024 (2004) through RF029 (2011). These indications appear to be stable or self-arrested with a high probability that they are the result of inter-granular stress corrosion cracking (IGSCC) due to their jagged, intermittent appearance and how they follow the grain boundaries. There is visual evidence of heavy grinding in the area of the indication. IGSCC eventually slows down or arrests because the flaws grow through or away from the localized areas of residual stress. Without evidence of crack growth over several cycles the crack growth rate of 5x IOE-05 in/hr should not be applied to the flaw indications, and therefore no crack growth calculations exist.
Higher quality inspection tooling started being used in RF027. It was instrumental in identifying the horizontal flaw at the HAZ of drain channel to support ring weld in RF028. Also, confirming the stop and end points of the vertical flaw at weld DC-Page 4
V4C, which in all likelihood were pre-existing prior to being identified with newer technology. Based on the stable behavior of the DC-V4C indications during the past four operating cycles under EPU conditions, the propagation of the IGSCC flaw by fatigue during at least the next two cycles is unlikely.
The drain channel is connected to the steam dryer assembly by welds on three edges.
The more structurally important steam dryer skirt plate is not affected by the DC-V4C internal drain channel indications. Further, the 3 and 6-inch drain pipes that are welded to the drain channel section near the crack provide some added structural redundancy to the upper portion of the drain channel sections on either side of the cracked weld. Also, the flaw indications in the DC-V4C weldare not through-wall, as there is no evidence of steam leaks or surface deterioration observed in the area.
The drain channel DC-V4C flaws are in the non-structural portion of the dryer (i.e., it is not located in the skirt structure itself). The vertical flaw is 15 inches or 16.3% of the weld length. Therefore, it is expected that the crack will have no significant impact on dryer performance and will not be likely to result in loose part until the crack length exceeds 50% of the weld length or 46 inches (
Reference:
GENE-0000-0028-0130-02, Revision 2, dated April 2004). In the unlikely event that the flaw grows at the rate of 5x 10-05 in/hr, it would take considerable more than three 18-month operating cycles to reach 50% of the weld length. An additional flaw length acceptance criteria for this weld has been conservatively evaluated as 15.6 inches in length at which fatigue crack extension could take place (
Reference:
NRC Issuance of Amendment Re: Extended Power Uprate transmitted by Letter NVY 06-028, dated March 2, 2006). Without evidence of crack growth resulting from fatigue, the indications will be monitored by in-service inspection. This conclusion is based on industry experience with IGSCC flaws in BWR steam dryers.
Table 1 provides flaw indication summary and an engineering disposition as further evidence of acceptance for continued operation, with the following information:
. Location of the indications - grouped by regions of the steam dryer.
- Distribution of indications - i.e. random, concentrated at high stress locations, in the heat affected zone (HAZ).
- Length of indications.
- Characterization of the indications - i.e. likely damage mechanism, suspected rate of growth, consequences of failure, crack growth discussion.
- Engineering disposition of the relevant indications (> 1/16") based on the loading conditions.
- 4. Summary and Conclusions Entergy proposes that the steam dryer inspections be performed once every third refueling outage in accordance with section 5.3 of BWRVIP-139-A (and two refueling outages in the current re-inspection cycle for the indications in the area of the DC-V4C weld). This means that no steam dryer inspection would be Page 5
performed in RFO30, but would be required in RFO3 1. Entergy believes that performing steam dryer inspections every third refuel outage provides an adequate degree of safety and quality based on the following:
" The pre-emptive modifications to the steam dryer are designed to preclude the failures experienced at EPU conditions in other BWR-3 steam dryers. The modifications increased the structural integrity of the steam dryer and the replaced hardware material is less susceptible to IGSCC.
" The VY Steam Dryer inspection has been extensive and the results provided a high level of confidence that the dryer is in good condition.
" Five (5) successive steam dryer inspections have been completed since 2004; in RFO 24, 25, 26, 27, 28, and an additional inspection of the DC-V4C weld area indications in RFO 29. The inspection results show that the flaw indications caused by IGSCC have stabilized or arrested and that no further or minimal growth is therefore expected. This is also seen in-the areas of remaining ligaments over the length of the longest flaws as there is no gonidence of change. Also, there is no evidence of crack growth post EPU for all other steam dryer flaws.
Therefore, it would be unreasonable to postulate the crack growth rate of 5xl OE-05 in/hr.
" The limiting flaw in the HAZ of weld DC-V4C has been evaluated by two separate acceptance criteria and determined that there is no crack growth resulting from fatigue and no potential for craok growth exists.
- The inspections have met and exceeded the requirements of SIL-644, Rev. 2 and BWRVIP- 139-A.
" Extended Power Uprate (EPU) was implemented in May 2006 with no fatigue induced flaws 'identified since implementation.
- Monitoring was performed on the Main Steam System during and after EPU with no acoustic issues deemed to be structurally detrimental to the steam dryer.
" Over the inspection period, enhanced inspection capabilities (delivery systems and cameras) have allowed greater definition of flaws, verification that flaws thought to be new actually are pre-existing, and verification of flaws having self-arrested.
" No identified flaws in major elements of the steam dryer have been directly attributed-to fatigue related failures.
- No through-ýwall cracking.
" The Steam Dryer is free of structural damage.
" The Steam Dryer is non-safety related equipment with no generation of loose parts concerns.
" Reduced inspection frequency will be sufficient to detect growth in the existing flaws, if any, before the flaw reaches a length that could result in the generation of loose parts.
" The existing flaws would not cause any detrimental effect on the functionality and the structural integrity of the steam dryer, or have any potential to affect any safety related equipment.
" Vermont Yankee monitors the Main Steam System for evidence of moisture carryover with no evidence of abnormal moisture carryover noted to date.
Page 6
Table I - Steam Dryer Indication Summary Indication Component Distribution of Indication Characterization of Indication and Location Reference Crack Growth I Weld ID Indication Length Engineering Disposition Documents Discussion Lifting Lug Dryer Lifting Stitch welds Length of These are linear indications indicative of Indications Lug 1440, GENE 0000-0068- The cracking in the cracked at high indications are all cracked stitch welds that prevent the lifting 4787 Rev.1 stitch welds is 2150 & 3240 stress locations, or part of the rods from bAcking out (unthrading).
not in heat (144-) & 0000- caused by a high length of the stitch Lifting rods were tightened to 225 lbf-ft of 0092-7429-RO affected zone stress condition due weld. Stitch welds torque before welding. Cracking is likely (2150 & 3240)
(HAZ). are approximately to imbalance loading due to an overload condition during removal at the lifting lug one inch in length. or replacement of the steam dryer. INR's: support. The Inspections show no evidence of lifting rod VYR26-07-O1R1 cracked stitch welds movement or rotation. Indications have VYR27-06 are of no structural been evaluated as being acceptable for VYR27-08 concems as the continued operafion* Refer to Reference VYR27-24 purpose is to keep Documents fora detailed evaluation. VYR28-05 VYR28-09 the lifting rods in place and to prevent Vrotation of the threaded connection.
Page 7
Indication Component Distribution of Indication Characterization of Indication and Reference Crack Growth Location I Weld ID Indication Length Engineering Disposition Documents Discussion Dryer Leveling Tack welds All tack welds of These are linear indications indicative of GENE 0000-0068- The cracking in the Leveling Screws 144, cracked at high approximately cracked tack welds that prevent the leveling 4787 Rev. 1 (144) stitch welds is Screw 215, &324 stress locations, one inch in length screws from backing out (unthreading). & 0000-0092- caused by a high Indications not in HAZ. are cracked Leveling screws were tightened to ISO Ibf-ft 7429-RO stress condition due entirely. torque before welding. These cracks are (215 & 324) to impact loading likely the result of impact loading during during reactor reactor operation. These indications have INR's: operation. The been evaluated as being acceptable for VYR26-07-02-R2 cracked stitch welds continued operation. Refer to Reference VYR27-02 are of no structural Documents for a detailed evaluation.
- VR27-04 VYR27-10 concerns as the VYR28-06 purpose is to keep VYR28-08 the leveling screws Vin place and to prevent rotation of the threaded connection.
Page 8
Indication Component Distribution of Indication Characterization of Indication and Reference Crack Growth Location I Weld ID Indication Length Engineering Disposition Documents Discussion Drain DC-V4C Randomly Intermittent These linear indications are all indicative of GENE-0000-0028- There has been no Channel distributed, in indication of 15 Intergranular Stress Corrosion Cracking 0130-02, Rev. 2; evidence of crack Indications the weld HAZ. inches in total (IGSCC) in the heat affected zone of drain 0000-0092-7429- growth since EPU length at weld channel weld DC-V4C. This indication was RO &0000-0117- inspections in DC-V4C. first identified in RF024. It was observed 4244-R 0 RF026.
again in RF025 and RF026 with no change intermittent noted. In RF027, a slight increase in length INR's:
indication of 9.9 was observed. This change was attributed VYR24-04-04-R2 inches in total to newer technology allowing greater access VY-RF025 Data length in the drain to the indication location and improved Sheet channel to camera capability (resolution). In RF028 a VYR26-07-05-Rl VYR27-05-R2 support ring weld. horizontal indication was observed in the VYR28-2 Drain Channel to Support Ring weld. This VYR28-3-R2 indication was also attributed to IGSGC. VYR29-1 1-01 Review of previous visual inspin videos in this area indicated that the indication was pre-existing although the quality of the earlier videos was not sufficient to confirm length.
The indication was re-inspected in RF029 with no change observed. This indication appears to have self-arrested with no further growth anticipated and no potential for loose parts exists. Refer to Reference Documents and Sections 3 &4 of this RAI Response for a detailed evaluation.
Drain DC-H-30 Randomly Indication #1 is These linear indications are indicative of GENE-0000-0028- There has been no Channel (DCC-DP- distributed, In approximately 3 IGSCC in the heat affected zone of drain 0130-02-R2 evidence of crack Indications 12) the HAZ and inches in length; channel weld DC-H-30 located at growth since EPU adjacent to a Indications #2 & approximately 1850. The indications have INR's: inspections in drainpipe-to- #3 are very small shown no evidence of growth and were VYR24-04-04-R2 RF026.
drain channel (< 1 inch in evaluated as being acceptable for continued VYR2.6-07-17 weld length), located operation and no potential for loose parts VYR28-17 on the other side exists. Refer to Reference Documents for of the drain pipe. detailed evaluation.
Page 9
Indication Component Distribution of Indication Characterization of Indication and Reference Crack Growth Location I Weld ID Indication Length Engineering Disposition Documents Discussion Drain DC-H-27 In the HAZ, Approximately 4.6 This linear indication is indicative of IGSCC GENE-0000- There has been no Channel adjacent to a inches in length or in the heat affected zone of the drain 0092-7429-RO evidence of crack Indications drainpipe-to- 17% of the channel weld DC-H-27. This indication has growth since EPU drain channel elliptical drain existed since RF024, and has been INR's: inspections in weld pipe to channel observed during RF027 with the RFO28 VYR24-04-04-R2 RF026.
weld inspection revealing no apparent change. No VYR27-03-R1 circumference potential for loose parts exists. Refer to VYR28-02 Reference Documents for detailed evaluation. _,_ __....
Steam Steam Dam Randomly Three indications These are linear indications indicative of GENE 0000-0068- There has been no Dam Support at distributed, not all less than one IGSCC located on the edge of the steam 7307, Rev.1 evidence of crack Indications 350 in the weld HAZ. inch in length dam plate in an area of noapplied stress growth since EPU and do not appear to be associated with any INR's: inspections in fatigue related issue. Possibly due to cold VYR26-07-07 RF026.
work as the plate might have been cut or VYR27-07 ground such that the IGSCC susceptibility VYR28-13 was increased. No potential for loose parts exists. Refer to Reference Documents for detailed evaluation.
Page 10
Indication Component Distribution of Indication Characterization of Indication and Reference Crack Growth Location I Weld ID Indication Length Engineering Disposition Documents Discussion Unit End HB-V01, Randomly A total of five Three of total five linear indications are GENE-0000-0047- There has been no Plate HC-Vo1, distributed, in Indications all indicative of IGSCC associated with areas of 2767 Rev. 1 & evidence of crack Indications HD-V04, the HAZ. appear to be less cold working and are not expected to 0000-0092-7429- growth since EPU HE-V02 than one inch in propagate. The other two indications appear RO inspections in length. to be small fabrication induced crater cracks. RF026.
The indications have shown no evidence of INR's:
growth and were evaluated as being VYR24-04-02-R2 acceptable for continued operation. No VYR25 -01 to 07 potential for loose parts exists. Refer to VY2-07-09-R1 Reference Documents for detailed WM6-07-10-R1 evaluation. VYR26-07-12-RI VYR26-07-13tol6 Several additional indications previously VYR26-07-18-Rl recorded as relevant were later on re- VYR26-07-19-Ri assessed With, higher quality inspection VYR26-07-20 tooling and determined to be non-relevant. VYR27-01 VYR27-14 to 17 VYR27-18-R1 VYR27-19-Ri VYR27-20 to 23 VYR28-01 VYR28-11 &12 VYR28-16
_ _ __ _ _VYR28-18
_ _ _....._ to 23 Page 11
The inspections that were conducted during RFO 26, 27 and 28 include areas that were newly modified during RFO-24.
Inspections-RFO Number of new Location of the Possible aging Remarks.,
indications indications degradation To -29 19 indications were IGSCC-cold work Confirm whefher on vepijaLgldes at Type of 304 that was stress relieving 175 , and one used in RFO-24-L or treatment was indication at 2150. non-L grade? performed after The indications are welding. All these perpendicular to Some indications- indications that were vertical guide channel fatigue welds-IGSCC; 3 characterized are definitely cracks-AO~~
indications at the depth is unknown-Steam dam support at fracture mechanics 350. -2004 cannot be used.
modification with new Qualitative judgment welds cold work- -very arbitrary and IGSCC; 5 indications nebulous at lifting rods and dryer screws -fatigue; 1 indication-dryer vane-IGSCC.
Note-No justification-(a) crack is self arresting, (2) flaw tolerance; (3) stresses due to welding/grinding; (4) no quantitative analysis
-(5) further inspections during RF27/RF 28-did not monitor these indications-no length of the indications recorded. - to justify lower inspection frequency-PROVIDE technical basis.
Inspections-RFO Number of new Location of the Possible aging Remarks indications indications degradation Tot 2 indications were on IGSCC-cold work Confirm whether vertical guides at 3240 Type of 304 that was stress relieving and 4 indications on used in RFO-24-L or treatment was dryer rods at 2150 and non-L grade? performed after 324 0-possible welding. These new fatigue? The indications are indications are located at areas that perpendicular to are different from vertical guide channel those identified in welds-IGSCC; 3 RFO-26 and RFO-indications at the High stress/low Steam dam support at stress-COLD 350. -2004 WORK?
modification with new welds cold work-IGSCC; 2 indications-dryer drain channel vertical weld-IGSCC.
Inspections-RFO Number of new Location of the Possible aging Remarks indications indications degradation One new indication Extension of an Not discussed none existing indication -
use as is-location-DC-V-4C
parties herein. The record will be held open with regards to Contentions 2A and 2B, and Contention 2 will be held in abeyance until 45 days after those events occur.
B. Contention 3 Entergy's License Renewal Application does not include an adequate plan to monitor and manage aging of the steam dryer during the period of extended operation.
With regard to Contention 3, the Board concludes, with the proviso noted below, that Entergy has demonstrated that its proposed aging management program for the steam dryer will adequately manage the effects of aging during the 20 year license renewal period, as equired by 10 C.F.R. §§ 54.21 (a)(3), (c)(1)(iii) and that it meets the reasonable assurance standard of 10 C.F.R. § 54.29. In so ruling, we are relying solely on the first branch of Entergy's proposed steam dryer AMP, i.e., Entergy's commitment to continue its existing Steam Dryer Monitoring Program (including GE-SIL-644, Revision 2, wh'iich is incorporated therein) during the period of extended operation. The second branch of Entergy's proposed steam dryer AMP, i.e.,
proposed BWRVIP-1 39, is subject to multiple contingencies and is not in the evidentiary record, and therefore nothing herein constitutes our reliance on or approval thereof.
Our conclusion that Entergy's proposed steam dryer AMP meets the relevant requirements subject to the mandatory proviso that the renewed license include the following express condition: "Notwithstanding any other provision, Entergy shall continue to perform and implement the continuous parameter monitoring, moisture content monitoring, and visual inspections specified in the AMP, at the intervals specified in GE-SIL-644 Revision 2. These shall continue for the full term of the PEO unless this provision of the license is duly amended."
C. Contention 4 Entergy's License Renewal Application does not include an adequate plan to monitor and manage aging of plant piping due to flow accelerated corrosion during the period of extended operation.
With regard to Contention 4, the Board concludes that Entergy has demonstrated that its proposed aging management program for the flow accelerated corrosion of plant piping will 152