HL-5437, Forwards Revs to Ei Hatch GL 88-01 & NUREG-0313 Commitments Re Third 10-year Interval Inservice Insp Program
| ML20151J355 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 07/30/1997 |
| From: | Sumner L SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0313, RTR-NUREG-313 GL-88-01, GL-88-1, HL-5437, NUDOCS 9708050139 | |
| Download: ML20151J355 (20) | |
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Lewis Sumner Southern Nuclear
. Vice President Operating Compa:y,IIc.
. Flatch Project Support 40hvemess Parkway Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.7279 Fax 205.992.0341 SOUTHERN h COMPANY Energy to Sern Yourbid" July 30, 1997 Docket No. 50-321 HL-5437 50-366 ,
l U.S. Nuclear Regulatory Commission ATTN: Document ControlDesk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant Third 10-Year Interval Inservice Inspection Prograir.
NUREG-0313 and Generic Letter 88-01 Commitments Gentlemen:
By letter dated October 17,1995, the Third 10-Year Ir,terval Inservice Inspection Program for the Edwin I. Hatch Nuclear Plant was submitted to the Nuclear Regulatory Commission (NRC). This document contained ASME Code Section XIinservice inspection relief requests and proposed revisions to Generic Letter (GL) 88-01 and NUREG-0313 commitments. In subsequent discussions, the NRC requested additional information relative to the implementation of GL 88-01 and NUREG-0313. The requested information was provided to the NRC by letter dated January 26,1996.
By letter dated June 16,1997, the NRC issued the Safety Evaluation Report (SER) for the Plant Hatch ISI Program and concluded no deviations from regulatory requirements or commitments were identified in the Plant Hatch Third 10-Year Interval ISI Program.
Since the material submitted to the NRC revises Plant Hatch's commitments to GL 88-01 ,
and NUREG-0313, thereby deviating from the specific requirements called out in the two !
l subject documents, Southern Nuclear Operating Company (SNC) is not certain the NRC's SER addresses the revised commitments. Therefore, SNC requests verification the revised commitments are acceptable. l l
The principal changes to Plant Hatch's GL 88-01 and NUREG-0313 commitments are listed below. The attachment to this letter (the NUREG Section of the Third 10-Year ISI i h
Program) provides a detailed discussion of the subject program commitments.
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U.S. Nuclear Regulatory Commission Page 2 July 30, 1997
- 1. The examination frequency of some higher stress Category C welds was increased from once per 10 years to once every other outage. These welds are now listed as C',
as shown in the attache 1 NUREG Section of the JSI Program.
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- 2. The examination frequency of weld overlays was reduced from all every 2 refueling cycles to all every 10 years. In the 'evised schedule, approximately one-third of the I weld overlays will be examined every two refueling outages. !
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- 3. Scope expansion philosophy is riodified to allow the use of engineering judgment, in I conjunction with GL 88-01 and NUREG-0313 requirements, when determining scope expansions. Additionally, the initiation point for scope expansion of weld overlays is changed from indication of growth in the upper 25% of the original piping or component material to indication of growth into the effective weld overlay.
Since Unit 1 is scheduled to enter the next refueling outage on October 11,1997, acknowledgment of NRC approval is requested by August 8,1997. Should approval of the revised commitments require additional review time, the granting ofinterim approval ,
for two cycles of operation is requested based upon the following justifications:
- l. Without approval,37 additional weld overlay examinations will need to be performed during the 1997 Fall outage. This requirement could create a hardship in obtaining a sufficient number of qualified intergranular stress corrosion cracking (IGSCC) NDE personnel for the outage. This could impact the currently scheduled 35 day duration of the outage.
- 2. A one cycle deferral would impose a hardship, since Plant Hatch schedules nondestructive examinations in the drywell every other refueling outage.
Examinations have been scheduled, in this manner, to maximize the efficiency of the work effort in the drywell, in an ongoing attempt to reduce the overall outage duration. Additionally, performance of these 37 additional examinations after a two cycle deferral, in an outage where the NDE contractor is already mobilized to perform automated examinations, would require $150,000. In contrast, mobilizing the NDE contractor to perform automated examinations during the " unscheduled" Spring 1999 refueling outage would cost approximately $350,000.
l l 3. There is a total of fifty-four overlays located on Hatch Unit No.1 Recirculation System, RHR System, and RWCU System piping. Fifty-one were installed due to ultrasonic indications and are categorized as Category E. The remaining three were optionally applied and are categorized as Category E'. Overlays were installed in 1982,1984,1986,1988,1990, and 1991. There has been no indication of new l
4 U.S. Nuclear Regulatory Commission Page 3 July 30, 1997 3
cracking since the 1991 overlays were installed. Examinations have been performed numerous times on these overlays, ranging from a minimum of six times for the 1982 overlays to one to two times for the 1991 overlays. There has been no indication of crack growth into the effective overlay observed during any of the examinations; therefore, SNC believes that examining a representative sample of approximately one-third of the overlays during the upcoming Fall 1997 outage willProvide -
reconable assurance that the structural integrity of the overlays will continue to be malwined. This sample will consist of overlays installed ja 1982,1984,1986,1988, 1990, and 1991.
- 4. The revised conunitments are performance based, in that the frequency of examinations in non-problem areas is reduced, while the frequency of examinations in some higher Stress welds is increased. For example, while the overlay examination frequency has been reduced because there has been no associated problems detected ,
during the numerous examinations, SNC has increased the examination frequency of higher stress Category C welds from the required once per ten years to once every other refueling outage. During the 1997 Fall outage, four of these higher stress welds, now designated as C', will be examined.
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- 5. Plant Hatch first implemented hydrogen water chemistry on Unit 1 in 1987. Since that time, we have continuously monitored key parameters and adjusted the hydrogen injection rate to maximize our protection levels against IGSCC. As a result, we believe that the Recirculation System piping has been operating with full protection, other than during short excursions from normal, for at least three operating cycles.
This level of protection is believed to be the primary reason that we have seen no significant cracking since 1991.
SNC continues to believe the revised commitments provide reasonable assurance of the structural integrity of the affected systems, thereby maintaining an acceptable level of quality and safety such that the public health and safety will not be endangered.
Sincerely, H. L. Sumner, Jr.
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U.S. Nuclear Regulatory Commission Page 4 :
July 30, 1997 l
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Attachment:
NUREG Section of the Third 10-Year Interval Inservice Inspection (ISI) l Program l
cc: Southern Nuclear Overatine Company Mr. P. H. Wells, Nuclear Plant General Manager NORMS l
U.S Nuclear Regulatory Commission. Washington. D.C. '
Mr. N. B. Le, Project Manager - Hatch 1
US Nuclear Regulatory Commission. Reelon H ;
- Mr. L. A. Reyes, Regional Administrator l Mr. B. L. Holbrook, Senior Resident Inspector - Hatch i
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EDWIN 1. IIATCII NUCLEAR PLANT NUREG SECTION OF THIRD 10-YEAR INTERVAL INSERVICE INSPECTION (ISI) PROGRAM i
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. Hauh Unit 1 NUREG-0313 Summary Technical B==ie Dina=ian The following discussion is presented bared on each NUREG category as a topic. A description of the category definition and a brief summary of the Hatch experience within each category is presented. Inspection results along with new inspection frequencies and scope expansion criteria are provided. Also, the proposed reclassification ofwelds is identified where appropriate.
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Cateqrory A l l l l These are welds with no known cracks, that have a low probability ofincurring IGSCC problems, I because they are made entirely ofIGSCC resistant materials or have been solution heat treated after welding. Corrosion resistant clad is considenxi to be IGSCC resistant, and welds joining cast pump i
! and valve bodies to resistant piping are considered to be resistant weldments.
l The majority of Category A welds are longitudinal seam welds in the B31 Recirculation (RC), E11 Residual Heat Removal (RHR), and G31 Reactor Water Cleanup (RWCU) systems. The welds were solution annealed and are therefore, by NUREG-0313 criteria, considered resistant to IGSCC.
These have been inspected using a 25% sample criteria during the previous ten-year interval.
l l , In the future these long seam welds will not be inspected. Instead Code Case N-524 logic will be i used. This code case effectively eliminates the inspection oflongitudinal seam welds except for the portion that is included in the inspection boundary of the intersecting circumferential pipe weld. This should be the limiting location for long seam welds due to the proximity within the HAZ (heat affected zone). This was deemed technically acceptable by the ASME Code committees based on the extensive industry history of operation without a long seam failure. This case has been approved by ASME and on plant specific basis by NRC, but is not yet endorsed by the NRC in Reg. Guide 1.147.
Scope expansion for this type weld is not anticipated. This is based on industry experience used to support the Code Case N-524. Ifindications are found in the long seam area that are separate from the intersecting circumferential weld,Section XI scope expansion criteria for circumferential welds will be utilized.
l The remainder of the Category A welds are circumferential welds in the RWCU system, made of conforming material. The population is comprised of 19 circumferential welds (excluding 1G31-
- 1RWCU-6-D-15B and -1SC which are inaccessible due to piping design) and one weld (1G31-l 1RWCUM-6-D-9) that has ar; overlay. The overlay was applied during 1988 when the Class 1 l RWCU pipe was replaced. h was added to serve as a stress improvement process to mitigate the
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, Hatch Unit 1 NUREG-0313 Summary Catenorv A (continued)
( effects ofID grinding. The weld overlay will be rec 1mnified as Category E' (refer to details of Category E' elsewhere in this document) and as such, will be inan~ *M during the next ten-year ;
interval using the inspection and scope expansion criteria for that new category. 1 In 1993, the 19 circumferential welds received MSIP treatment as an additional measure to protect ;
j against crack initiation in conforming material. All 19 welds were inap +M during the 1993 outage )
to verify there were no detrimental effects associated with the MSIP process. Post-MSIP baseline l examinations revealed no indications. This also, for the 19 circumferential welds, satisfies the GL 88- l 01 requirement ofinspecting stress improved welds within two refueling cycles after the performance of stress improvement. Coincident with the beginning of this 10-year ISIinterval, the 19 :
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j circumferential welds will be inspected at a sample rate of 25% (5 welds) over the 10-year interval.
! This is consistent with the current ASME Section XI sampling technique and guidance of GL 88-01.
l The scope expansion rules of ASME Section XI for Class 1 piping will be used in the event )
l indications warrant. This is consistent with the GL and is technically valid based on the material j considerations. ,
l B--enu,nded Insocctions (Third Ten-Year Interval) for Catenorv A:
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. Circamferential welds - Examine 25% of the Category A welds over the ten-ycar interval with the examinations being spread equally over the ten years. This is consistent with ASME Section XI and GL 88-01.
. Longitudinal Seam Welds - Examine these welds in accordance vdth Code Case N-524. This effectively will eliminate the inspection of the long seams. The code case requires the inspection of the portion of the long seam that is contained within the boundaries of the intersecting circumferential weld. This will eliminate the need to examine 12 inches oflong seam either side of the circumferentialwelds.
. ASME Section XI scope expansion criteria will be utilized.
Previous Inspection Schedule (Second Ten-Year Interval) for Catenorv A:
. Examine 25% of the welds every ten years (at least 12% in six years per NUREG-0313).
. Scope expansion consists of an additional sample of welds, approximately equal in number and similar in distribution (according to pipe size, system, and location) to the original sample, unless there is a technical reason to select a different sample.
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Hatch Unit 1 NUREG-0313 Summary Catenorv C These welds are those whichjoin non-resistant materials, contain no evidence of flaws and were subjected to stress improvement (SI) treatment after more than two years of operation. GL 88-01 required ultrasonic inspection during the outage the SI occurred, once within two outages of the SI and then again within ten years.
When the initial GPC commitment to GL 88-01 was made, the examinations required to be completed within 10 years were compressed to a schedule of approximately eight years after SL This was to coincide with the end of the current ten-year interval. This schedule has been altered several times due to outage constraints and IGSCC indications in some Category C welds. Since the initial commitment was made, scope expansion examinations combined with the regularly scheduled i examinations have resulted in a significantly larger number of examinations than anticipated. In fact, all but a small number of Category C welds have been in=pm-I beyond the original commitment.
A large number of welds received Induction Heat Stress Improvement (IHSI) treatment during the l
1986 outage. Since that time, the only 12" welds that received weld overlays were two safe-end to nozzle welds and welds that were previously classified as category F (known cracking). This indicates that the SI treatment was effective for the 12" pipe.
7- The 28" inch pipe had twelve welds overlayed due to IGSCC indications during the 1990 outage (1B31-1RC-28A-2, -4, -6, -7, -8, -14 and IB31-1RC-28B-8, -9, -10, -13, -14, -15) and one additional weld (1B31-1RC-28B-2) was overlayed in 1991. The occurrence ofindications has decreased to the point that no reportable indications were noted during the 1993 outage. This is likely the result of hydrogen water chemistry (HWC).
Additional welds were added to the Category C group following the 1993 MSIP of Category D welds. These welds had no evidence of cracking following the MSIP.
The total number of Category C welds is 78. GPC will continue the inspection of the Category C ,
welds consistent with the guidance of GL 88-01, i.e. once per each ten-year interval. The welds I reclassified as C' (refer to details of Category C' elsewhere in this document) will be examined at a frequency of every other outage.
Scope expansion will be developed by GPC each outage based on the indications that occur. It will ,
be based on system, size and any other appropriate parameters. GPC will determine the sample expansion without NRC advance approval, but will provide the sample expansion to the NRC for concurrence at the beginning of the inspections. (This logic is similar to that used by GPC in previous 0313. DOC Rev.O Page 3 of12
Hatch Unit 1 NUREG-0313 Summarv l
Catenorv C(continued) lf outages (1988-1995). In each case the saniple expansion proposed by GPC was approved by the NRC).
l Recornmanded Inanections (Third Ten-Year Intervan for Catenorv C:
l . Evamine all Category C welds during the ten-year interval with the examinations being spread I approximately equally (frequency = 1/3 of category total every other outage) over the ten years.
. Scope expansion will be determined on a case-by-case basis as a function of size, system, etc.
Previous Insoection Schadole (Second Ten-Year Intervan for Category C:
. Framine all welds within the next two refueling cycles, then all every ten years (at least 50% in
! six years).
. Scope expansion consists of an additional sample of welds, approximately equal in number and j
similar in distribution (according to pipe size, system, and location) to the original sample, unless l
there is a technical reason to select a different sample.
Catenorv C' (GPC/SNC designation) i There are 12 welds, previously Category C, that have stresses excMng 1.0 Sm. Eight of these 7-( welds are "# 1" welds (header to riser pipe welds) that historically have not been an industry problem. The other four welds consist of one riser-to-safe-end weld (#4) and three safe-end-to-l nozzle welds. These four welds (1B31-1RC-12AR-H-5, -J-4, -J-5, and 1B31-1RC-12BR-D-5) will be classified as Category C'.
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Recommended Insoections (Third Ten-Year Intervan for Catenorv C':
. Examine each weld every other outage.
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. Scope expansion willinvolve Category C welds and should be determined on a case-by-case l basis as a function of size, system, etc.
t Previous Insoection Schedule (Second Ten-Year Intervan for Catenorv C'-
. None. This is a new GPC/SNC designation for the Third Ten-Year Interval.
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- Hatch Unit 1 NUREG-0313 Summary Catenory D
( These are welds made with materials not resistant to IGSCC and that have not been given an SI treatment, but have been inspected by qualified examiners using qualified procedures and been found to be free of cracks. Category D welds will be inspected at least once every two refueling cycles.
Approximately half of the Category D welds in the plant will be inspected each refueling outage.
All circumferential welds previously classified as Category D received MSIP treatment during the 1993 outage and are now clammified as Category C. One additional weld previously classified D by GPC/SNC, is a diumimilar pipe weld that has an overlay. It will be reclassified as E'. The ten RINTSA (Recirculation Inlet Nozzle Thermal Sleeve Attachment) welds will be reclassified as Category R (see details elsewhere in this document).
The dissimilar metal weld with the overlay (1G31-1RWCUM-6-D-1) is the joint formed by the intersection of RWCU and RHR systems. The overlay was applied at the same time the RWCU pipe was replaced during the 1988 outage. The overlay was added to provide additional mitigation of IGSCC in this dissimilar joint. There were no UT indications reported in the baseline examination or the subsequent examination in 1991. The weld overlay of the dissimilar metal weld was w= mined during the 1994 outage, was free ofindications penetrating the effective overlay, and will be reclassified as Category E'.
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With these reclassifications, there are no longer any Category D welds.
Recommended Inspections (Third Ten-Year Interval) for Catenorv D:
. Examine all Category D welds during the ten-year interval with the examinations being spread approximately equally (frequency = 1/3 of category total every other outage) over the ten years.
. Scope expansion criteria will be as described in GL 88-01, Supplement 1 for Category D welds.
Previous Inspection Schedule (Second Ten-Year Interval) for Category D:
. Examine all welds every two refueling cycles.
. Scope expansion criteria as described in GL 88-01, Supplement.1 for Category D welds.
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Ratch Unit 1 NUREG-0313 Summary Catenorv R (GPC/SNC desinnation) l( The ten RINTSA welds were originally in the Category D classi6 cation at GPC's option, but are outside the scope ofNUREG-0313. They were included due to the crevice that occurs where the thermal sleeve is attached to the nozzle. The current examination of this area will not detect flaws in the attachment weld. Instead, the exam is such that it will find flaws that might propagate from the
=**=chmant weld into the low alloy steel nozzle. The examinations performed to date have revealed
! no changes from the baseline examinations. Calculations have been performed estimating crack growth into the low alloy steel nozzle from a crack initiating in the crevice area. Based on those calculations, approximately 1/3 of the RINTSA welds will be examined every other outage. Should indications be detected, the scope expansion of GL 88-01, Supplement 1, for Category D welds will be used for RINTSA welds. The ten RINTSA welds will be raclammified as Category R.
Rsmm= lad _ Inanections frhird Ten-Year Intarval) for Cataanry R-
. Evamina all Category R welds during the ten-year interval with the examinations being spread approximately equally (frequency = 1/3 of category total every other outage) over the ten years.
. Scope expansion criteria will be as described in GL 88-01, Supplement 1 for Category D welds.
Previous Insoection Schedule (Second Ten-Year Interval) for Catenury R-
. None. This is a new GPC/SNC designation for the Third Ten-Year Interval.
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. Hatch Unit 1 NUREG-0313 Summuv i Catenorv E l
t These are welds with known flaws that have been reinforced by an acceptable weld overlay or have been mitigated by an SI treatment with subsequent qualified examination to verify the extent of cracking. GL 88-01 specifies that Category E welds should be inspected at least once every two refueling cycles after repair. Approximately half of them should be inspected during the first refueling outage after repair. The inspection method should provide positive assurance that the cracks have not progressed into the overlay. It is also desirable that the inspection procedure be capable of detecting cracks that originally were deeper than 75% of the original wall thickness, or that have grown to be deeper than 75% of the original wall thickness. An UT procedure qualified for overlay examinations must be used by examiners qualified to examine weld overlays. All Hatch welds classified as Category E or E' (refer to details of Category E' elsewhere in this document) have an overlay.
There are 52 Category E weld overlays (not counting the two 6" RWCU welds overlayed, but not due to any indication) at Plant Hatch, Unit 1. Of these overlays,48 are made with 308L and four are made with inconel weld metal. All overlays applied in 1982 and 1984 were resurfaced or built-up
! during the 1986 outage. All overlays are standard overlay design, intended for indefinite service.
l One overlay on the RHR system (1E11-1RHR-20B-D-5) was added to ensure an adjacent overlay l
could be properly inspected, and has been rH===Med u Category E'. The two 6" RWCU welds, 1G31-1RWCUM-6-D-1 and 1G31-1RWCUM-6-D-9, have also been reclaulfied as Category E' for ease of tracking overlayed welds.
An overlay inspection history summary follows:
. Of the 23 overlays applied and inspected in 1982 and 1984,21 were inspected in 1986. Nine new I
overlays were added and inspected in 1986.
. Of the 32 overlays in place in 1986, 23 were inspected in 1987. This included seven of the nine overlays applied in 1986 and 16 old overlays being examined for at least the second consecutive l outage. No new overlays were applied during 1987.
. All 32 existing overlays were inspected in 1988 as were two new overlays for a total of 34 overlay examinations.
l . All 34 existing overlays plus 12 new overlays were inspected in 1990 for a total of 46 overlay examinations.
. All 46 existing overlays plus six new overlays were inspe:ted in 1991 for a total of 52 overlay
- examinations.
! . Of the 52 existing overlays in place in 1993,26 were f.nspected. This included three of the six
! overlays applied in 1991. No new overlays were applied during the 1993 outage.
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Hatch Unit 1 NUREG-0313 Summarv i Catenorv E (continued) f . Of the 52 existing overlays in place in 1994 (including 1E11-1RHR-20B-D-5, now classified as j
E') , all 52 were inspected. Not included in this count are reclassified E' welds 1G31-1RWCUM-6-D-1 waminad in 1994 and 1G31-1RWCUM-6-D-9, last &=minad in 1991. No new overlays were applied during the 1994 outage.
It is noteworthy that in all the examinations performed to date on the welds overlays, there have been i I
l no problems encountered. Considering the length of time some overlays have been in place and the l stresses, some indication growth under the overlays could reasonably be expected. However, while there have been some minor changes in a few of the indications under the overlays, only one overlay l (IB31-1RC-12AR-F-2) has an indication that now appears to be at the pipe-to-overlay interface; but, it has not pek.ted the effective overlay. (NOTE: The effective overlay is that portion of the overlay for which full credit is taken It does not include the dilution zone or initial weld layer unless that layer has been determined to meet appropriate acceptance criteria.)
The Hatch inspection experience alone warrants a change in the inspection and scope expansion
- criteria for the weld overlays. When the inherent resistance to IGSCC of the overlay materialis considered, the issue is not whether the inspection frequency should be changed, but by how much should the inspection' frequency be changed. This is especially true for the overlays made of 308L.
This material has been shown to be more resistant than 316NG pipe base metal that is considered resistant material and is sample inspected using Category A criteria.
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Based on the performance of the overlays and their resistant nature, the inspection criteria should be revised. Coincident with this ten-year ISI interval, the inspection frequency for the Category E and E' overlay welds will be once per ten-year interval. The examinations will be scheduled such that approximately 1/3 of the overlays will be inspected every second outage.
The scope of overlays to be examined in any one outage will be expanded for the following conditions:
. An indication extends into the effective overlay material, or
. An indication found that appears to be growing in a manner that would indicate a flaw could reasonably be expected to propagate axially beyond the overlay. Based on guidance from L Section 4.2 ofNUREG-0313, Rev. 2, it can be argued that axial growth is unlikely. The l argument is presented there that axial flaws will grow through-wall in marginally resistant
- material, but crack length will not extend beyond 1.5 times the pipe thickness (1.5t). In addition
,! to the NUREG information it can be shown that although a new heat affected zone is created by 0313. DOC
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l Hatch Unit 1 NUREG-0313 Summary Catenary E (continued)
I application of the overlay, the stresses are low enough and the distance is great enough that crack propagation in the axial direction is not an immediate issue.
For either of the cases described above, a reexamination of that overlay will be conducted for three l consecutive periods.
t l RMnmmandad Innnections (Third Ten-Year Intarvan for Cataanry E:
. See Category E' description.
Previous Insnection Schedule (Second Ten-Year Intervan for Ca**enry E:
. See Category E' description.,
Catenorv E' (GPC/SNC desinnation) l This is an arbitrary designation u' sed by GPC. The E portion of the designation signifies that it is a weld with a standard Category E overlay. The " prime" indicates it is not a true Category E in that the weld was not flawed when the overlay was applied. The welds are: 1G31-1RWCUM-6-D-1;-
1G31-1RWCUM-6-D-9; and 1E11-1RHR-20B-D-5. The inspection and scope expansion for l
Category E' will be the same as the new criteria used for Category E.
Recommended Insoections (Third Ten-Year Intervan for Catenorv E and E' (GPC/SNC designation):
. Examine all Category E and E' welds during the ten-year interval with the examinations being spread approximately equally (frequency = 1/3 of total population for both categories every other outage) over the ten years. Weld 1B31-1RC-12AR-F-2 will be exam'med during each of the first two outages in which inspections are conducted to verify significant indication growth has not occurred.
. There will be no scope expansion unless an indication extends into the effective overlay or the indication is such that axial propagation out from underneath the overlay is anticipated. If these conditions occur, scope expansion will be based on size, system, age of the overlay, etc. with the sample size dictated by the situation based on the particulars of the flaw.
Previous Inspection Schedule (Second Ten-Year Intervan for Catenorv E:
. Examine 50% of the welds at the next refueling cycle (either 1987 or 1988), then all every two
! refueling cycles.
0313. DOC Rev. O Page 9 of12
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Hatch Unit 1 NUREG-0313 Snxu=v Previous In= Mon Schaduta (Second Ten-Year intarval) for C=+aanry E (continued);
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Scope expansion will be required for significant crack growth, or additional cracks found during the inspection of one or more Category E welds. All other Category E welds should be 3 a=ninad See GL 88-01 for definition of significant crack growth.
j Previous Inmaae+ ion Schadala (Second Ten-Year Intarval) for Ca*aaorv E':
i . None. This is a new designation for the Third Ten-Year Interval.
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Catemory P (GPC/SNC desinnation) l This category was arbitrarily defined by GPC to identify those longitudinal seam welds which have i
- been covered by weld overlays. In this condition the long seams are not inanac+=hle and in reality I
- have no need to be inspected. Classification as Category P allows historical information to be j maintained without impacting the inapaction tables. No inWons will be performed. Tliis is now I supported by Code Case N-524 also. Verification of weldm ' tegrity is accomplished by overlay '
examinations.
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" Recommended Inspections (Third Ten-Year Interval) for Catamorv P (GPC/SNC daaien=+ian):
. No examinations required. Covered by Category E and E' inWons.
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Previous Inanection Schadute (Second Ten-Year Interval) for Catamory P:
. None. This is a new GPC/SNC designation for the Third Ten-Year Interval. I
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0313. DOC Rev.O Page 10 of12
Hatch Unit 1 NUREG-0313 Summarv i Catemory S (GPC/SNC desienation)
- ( The Category S classification was arbitrarily defmed by GPC to designate those non-safety RWCU welds that are augmented by GL 88-01. Approximately 30% of these welds have been avamin A four times u of 1994 with no reportable indications. GPC has now decided to select approximately i
a 10% of the population for repetitive examination each outage. This provides a better ===anament of
- change occurring within the system while reducing the amount of weld preparation time and
! therefore personnel radiMion dose.
j The current inspection program will continue until NRC agrees with the GPC position that the RWCU isolation valves (F001 and F004) meet the criteria of GL 89-10. At that time, the lnWn j of these welds may be discontinued at the discretion of GPC, based on guidance in Supplement 1 to GL 88-01.
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l There are no generic NRC guidelines in place specifying scope expansion in the event reportable
{ indications are identified. The current agreement between NRC and GPC is that GPC will contact l NRC in the event of reportable indications and a scope expansion will be developed. However, this l is the agreement reached several years prior to the GPC initiated sampling plan being endorsed via j Supplement 1 to GL 88-01. Therefore, for the Third Ten-Year Interval, criteria similar to ASME i, Section XI will be used for determining additional examinations. This will require that an additional i' sample equal in size to the initial' sample inspected be avamia d. If reportable indications are found in the second sample, GPC will then contact NRC to develop a mutually acceptable course of action. l j Recommended Insoections (Third Ten-Year Interval) for Cateoorv S (GPC/SNC da=ionationh j . Examine 10% of the Category S welds per outage. This sample will come from the welds already j examined to continue assessing change from one examination to the next.
l
. A scope expansion sample will consist of an additional sample of equal size to that used for the j outage. If additional indications are detected, the NRC will be contacted and a mutually
! agreeable course of action will be developed.
1 i Previous Insoection Schedule (Second Ten-Year Interval) for Catenorv S (GPC/SNC da=ionationh _
- . None. This is a new GPC/SNC designation for the Third Ten-Year Interval.
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t t' 0313. DOC Rev.0 Page 11 of12
F=+ch Unit 1 NUREG-0313 Summary Catenory L (GPC/SNC desinnatiop)
( This category was arbitrarily defined by GPC to identify welded at+=chments (lugs). There are no special requirements. ASME Section XI requirements will be used.
Racommandad inmMons (Third Ten-Year Intervan for C=+aeorv L (GPC/SNC da=imetanh
. ASME Section XI requirements will be used.
l l Previous inMon Schadnte (Second Ten-Year intarvan for Cataanry L (GPC/SNC da= ion =+iont l . ASME Section XIrequirements used.
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0313. DOC l Rev.0 Page 12 of12 l
ll 1 -
Hatch Unit 2 NUREG-0313 Su . -.v
}f i
This is a supplernent to describe Unit 2. Refer to the discussion provided in the Hatch Unit 1 NUREG-0313 Summarv for specific details common to both Unit 1 and 2.
General i A portion of the original stainless steel piping in Hatch 2 was made of conforming (IGSCC resistant) materials. Actions taken by Georgia Power Company to mitigate IGSCC in non-conforming materials consist of the Recirculation System (2B31) pipe replacmamat (except for the safe-ends) with construction designed for a minimum number ofwelds, j IHSI (Induction Heat Stress Improvement), and the implementation of an inservice 4
inspection program. A Hydrogen Water Treatment system was also put in place.
l Catenory A -
A total of 222 (including 84 longitudinal seams) welds are in this category. .
l j- Recommended inmections (Third Ten-Year Intarval) for Ca+aaory A-1 Circumferential welds - Examine 25% of the Category A welds over the ten-year
- interval with the examinations being spread equally over the ten years. This is ;
consistent with ASME Section XI and GL 88-01. I
. Longitudinal Scam Welds - Examine these welds in accordance with Code Case N-
, 524. This effectively will eliminate the inspection of the long seams. The code case j requires the inspection of the portion of the long seam that is contained within the
, boundaries of the intersecting circumferential weld. This will eliminate the need to
] examine 12 inches oflong seam either side of the circumferential welds.
j . ASME Section XI scope expansion criteria will be utilized.
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i Previous Insoection Schedule (Second Ten-Year Intervall for Catenorv A:
Examine 25% of the welds every ten years (at least 12% in six years per NUREG-3 0313).
{ Scope expansion consists of an additional sample ofwelds, approximately equalin number and similar in distribution (according to pipe size, system, and location) to the j original sample, unless there is a technical reason to select a different sample.
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) Catenary B
- None currently in service.
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i 0313#2. DOC i Rev.O Page1of3 l
l l
. Hgeh Unit 2 AUREG 0313 Summary
(~ Catepon C A total of 50 welds are in this category.
Ten Recirculation System inlet safe ends and two outlet safe-ends were treated with the IHSI process in 1986. Post-IHSI baseline examinations revealed no indications.
The safe-ends for the four Peedwater nozzles (total of 11 welds); the two Jet Pump instrumantatina assemblies; the two Core Spray nozzle safe. ends; and the Control Rod Drive nozzle cap had MSIP treatment in 1994. Post-MSIP banaline araminatiana revealed no indications. These welds will need an examination within two ra8_= Hag cycles, aAer the stress improvement.
Bus ==ndad inanac+ian= (Third Ten-Year Tatarvan for Ca*= v C:
Examine all Category C welds during the ten-year interval with the araminatians being spread approximately equally (frequency = 1/3 of category total every other outage) over the ten years.
Scope expansion will be determined on a case-by-case basis as a function size, system, etc.
Previous Inmaaetion SchaAde (Second Ten-Year intarvan for Cataearv C:
Fvamina all welds within the next two refueling cycles, then all every ten years (at least 50% in six years).
Scope expansion consists of an additional sample ofwelds, approximately equalin number and similar in distribution (according to pipe size, system, and location) to the original sample, unless there is a technical reason to select a different sample.
t 0313#2. DOC Rev.O Page 2 of 3
' Hatch Unit 2 MJREG4313 Summarv
- ~
( Catenorv DCat-:m R (GPC/SNC E':- at': )
A total of ten RINTSA (Recirculation Inlet Nozzle Thermal Sleeve Ateachmant) welds, previously in Category D at GPC's option, have been racleamiflad as C=+aaa y R. These welds, strictly =pa-Mag. are outside the scope of 0313 (see Hatch Unit 1 NUREG-1313 Summarv).
R=.: ....= dad laanae+iana (Third Ten-Year Tatarval) for r=+=r.rv R:
Examine all Category R welds during the ten-year interval with the araminatians being spread approximately equally (frequency = 1/3 of category total every other outage) over the ten years.
Scope expansion criteria will be as described in GL 88-01, Supplamant I for C=+agary D welds Previous Ta=aac+ian Schadata (Sacand Ten-Year Tr.:= val) for C =.srv R-
. None. This is a new GPC/SNC designation for the Third Ten-Year Interval.
Previous Inanacti on Schadale (Second Ten-Year intarval) for C=+aanry D:
Fr==ina all welds every two refueling cycles.
Scope expansion criteria as described in GL 88-01, Supplement 1 for Category D
(, welds.
Catenorv E One weld is in this category to be examined every 10 years.
One Feedwater nozzle safe-end weld (2B21-1FW-12AA-9) was overlayed in 1991 due to a linear indication. Subsequent exams in 1992 and 1994 showed no growth into the overlay.
i Racommandad Innnet ons (Third Ten-Year Intervan for Ca+=r.rv E:
Ev=mina all Category E welds during the ten-year interval Previous Insnection Schadule (Second Ten-Year Intarvan fer Cataooty E:
Examine 50% of the welds at the next refueling cycle (either 1987 or 1988), then all every two refueling cycles.
Scope expansion will be required for significant crack growth, or additional cracks found during the inspection ofone or more Category E welds. All other Category E welds should be examined. See GL 88-01 for definition of significant crack growth.
Catenory F and Catenorv G t None currentlyin service.
0313#2. DOC Rev.O Page 3 of 3
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