ML20107M057
| ML20107M057 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 04/23/1996 |
| From: | SOUTHERN NUCLEAR OPERATING CO. |
| To: | |
| Shared Package | |
| ML20107M046 | List: |
| References | |
| NUDOCS 9604300162 | |
| Download: ML20107M057 (7) | |
Text
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RE CTOR COOLANT SYSTEM 3/4.4.6 STEAM GENERATORS LIMITING COEITION FOR OPERATION 3.4.6 Each steam generator shall be OPERABLE.
APPLICA81LITY: MODES 1, 2, 3 and 4 ACTION:
With one or more steam generators inoperable, restore the inoperable generator (s) to OPERA 8LE status prior to increasing T above 200*F.
avg SURVE!LLANCE REQUIREENTS 4.4.6.0, Each steam generator shall be demonstrated OPERA 8LE by performance of the following aupented inservice inspection program and the requirements of Specification 4.0.5.
4.4.6.1 Steam Generator Sample Selection and Inspection - Each steam generator shall be determined OPERABLE during shutdown by selecting and inspecting at least the minimum number of steam generators specified in Table 4.4-1.
4.4.6.2.1 Steam Generator Tube 8 Sample Selection and Inspection - The steam l
generator tuoe minimum sample size, inspection result classification, and the corresponding action required shall be as specified in Table 4.4 2.
The inservice inspection of steam generator tubes shall be performed at the frequencies specified in Specification 4.4.6.3 and the inspected tubes shall be verified acceptable per the acceptance criteria of Specification 4.4.6.4 The tubes selected for each inservice inspection shall inc1rde at least 31 of the total number of tubes in all steam generators. Selection of tubes to be l
inspected is not affected by the Ffq, designation. When applying the exceptions of 4.4.6.2.1.a through 4.4.6.2.1.c. previous defects or imperfections in the L3h area repaired by sleeving are not considered an area requiring reinspection.
The tubts selected for these inspections shall be selected on a random basis except:
a.
Where experience in siellar plants with similar unter chemistry indicates critical areas to be inspected, then at least 505 of the i
tubes inspected shall be from these critical areas.
]
b.
The first sample of tubes selected for each inservice inspection (subsequent to the preservice inspection) of each steam generator shall include:
1.
All nonplugged tubes that previously had detectable nell penetrations greater than 205.
- When referring to a steam generator tube, the sleeve shall be considered a part of the tube if tne tube has been repaired per Specification 4.4.6.4.a.9.
FARLEY-UNIT 2 3/4 4-9 AENDENT NO. 63.64 9604300162 960423 PDR ADOCK 05000364 P
PDR s
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ara: :a ::::,Av; sysitx
$URVtI*.*.ANCE AEQUIREMENTS #::sa n naedi I
[teserv Inspection Aosults i
C-L Less than 5% of the total tubes inspected are degraced i
tubes and none of the inspected tubes are defective.
C-2 One or more tubes, but not more than 14 et,the total tubes inspected are defective, or between St and 10% of the total j
tubes inspected are degraded tubes.
[
C-3 j
More than 10% of the total tubes inspected are degraded tubes or more than 14 of the taspected tubes are defective.
Note: In all' inspections, previously degraded tubes er sleeves must i
exhibit significant (greater them 104) further well penetrations to be included in the above percentage culations.
i 4.4.4.2.2 Steam Generster PM !asseet:,se - In addities to the minimum sample size as determined by specif:,caties 4.4.6.2.1, all P/1.*
tubes will be inspected within the tubesheet reglea.
j inspection will not be a cause for additieeal inspections per TableThe results of this 4.4-2.
1 i
4.4.6.3 Inspecties Frecuencies - The above required inservice inspections of steam generater tubes shall be performed at the fellowing j
f,ogu.acies:
1
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a.
The first inservice inspectice shall be performed after 6
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Effective Full tower Meaths but withia 24 calendar anoths et l
i initial criticality. Subsequent inservice inspections shall
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be performed at intervals of not less than 12 mer more than j
24 calendar months after the psevious Laspecties. If two i
csasecutive inspectione following servies under JWPr canditions, not imeloding the preservice inspecties, result j
in all laspecties results falling into the C-1 category or if i
two consecutive inspections demonstrate that previously j
observed degradottes haa met osatiaued and as additismal degradaties has eteurred, the inspecties interval any be satended to a maximuun of esse per 40 aseths.
b.
i If the results of the inservies inspecties of a steam generater eenducted is seeerdamse with Table 4.4-2 at 40 meath Latervals fall in Catapry C-3, the inspectice frequemey shall be Sacreased to at least emee per 20 months.
The increase la inspecties fregeouy shall apply until the subsequest inspections satisfy the eriteria of specification 4.4.6.3.as the interval any than be eatended to a ma=*== of once per 40 months.
Additional, unscheduled inservice laspections shall be c.
performed as each stessa generater la aceerdenes with the first sample inspecties specified im Table 4.4-2 duriaq the shutdoom subsequent to any of the follouiag senditieas FAmigT-UlrIT 2 3/4 4 11 AseOIWT110. W l
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SEA ?0 2 ;00' AN? 3YSTD4 SURVt!!/JudCE REqutagMENTS (continuedt g.
Pluesine er Remair LLait means the imperfection depth at er beyond which the tube shall be repaired (i.e.,
miseved) er removed from service by plugging and is Jnator than er equal to 40% of the asainel tube well taickness.T Tw a d=8 tat **==
h--
= = = - -- N = = a k
- 7 NS dtsinidio n does Ad ag y l
. 3%.. g-- mj = 7 E{ g y b
.6.
for ides thai me,ei yke, tubeer For a tube that has been sleeved with a mechanical joiht sleeve, through well penetraties of h d c ed e t' t e n.
greater than er equal to 314 et sleeve nominal well thishness la the cleeve requires the tube to be removed from service by plugging. For a tube that has been sleeved with a welded joina sleeve, through well penetration greater them er equal to 316 et sleeve nestaal well thiekness is the sleeve between the weld joints requires the tube te be removed from servies by plugging. This definities does not apply to tube support plate intersections for which the voltage-based plugging ositerie are being applied. Refer to 4.4.6.4.a.14 for the plugging limit applicable to these latessections.
7.
Unserviceable describes the esadition of a tube er sleeve if it leaks er sentains a defest large eseugh to affect its structural integrity La the event of aa Operating Basis Eszthquake, a less-of-eeelaat accident, or a steam line er feeduster line break as spesified in
'^
- 4. 4. 6. 3. s, above.
8.
Tube Inspect 193 acons as inspectica of the steam generater tube from the point of entry that leg sidel cespletely around the Wabead to the tap suppert of the sold leg. For a tube that has been repaired by sleeving, the tube inspecties should imelude the sleeved pertion of the tube.
9.
Tube pesair refers to asahanical sleeving, as described by Westinghouse report WCAr 11178, Rev.1, or laser welded sleeving as described by Westinghouse report WCAP-12672, which is used to asiatain a tube in service er return a tube to service. This includes the removai of plugs that were installed as a corrective er preventive measure.
A FAALEY-UNIT 2 3/4 4*13e AMENOMENT Wo.106 l
+
m
F EACTOR CQi:. ANT SYSTEM
- SURVEILLANCE REQUIPEMENTS (Continuets 11.
F*
Distance is the distance of the expanded portion of a tube which provides a sufficient length of undegraded tube expansion to res;st pullout of the tube f rom the tubesheet.
The F* distance is equal to 1.79 inches and is measured down from the top of t..e tubesheet or the bottom of the roll
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j'f transition, whichever is lower in elevation.
12.
F* Tube is a tube:
a) with degradation equal to or greater than 40% below the F* distance, and b) which has no indication of imperfections greater than or equal to 20% of nominal wall thickness within the F* distance, and c) that remains inservice.
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j f, )dI.
Tube Expansion is that portion of a tube which has been increased in diameter by a rolling process such that no crevice exists between the outside diameter of the tube and the hole in the tubesheet.
l6.)(.
Tube Support Plate Repair Limit is used for the disposition of an alloy 600 steam generator tube for continued service that is experiencing predominately axially oriented outside diameter stress corrosion cracking confined within the thickness of the tube support plates. At tubesupportplatel intersections, the repair lindt is based on maintaining steam generator tube serviceability as described below:
Steam generator tubes, whose degradation is attributed l a.
to outside diameter stress corrosion cracking within the bounds of the tube support plate with bobbin voltages less than or equal to the lower voltage repair limit (2.0 volts), will be allowed to remain in service.
b.
Steam generator tubes, whose degradation is attributed l to out side dia.T.ete r stress corrosion cracking within the bounds Of the tube support plate with a bobbir.
voltage greater than the lower voltage repair limit
[2.0 volts', will be repaired or plugged except as noted in 4. 4. 6. 4. a.14. c below.
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l EARLEY-UNIT 2 3/4 4-12b AMENDMENT NO.
MACTOR COOLANT SYSTEM U
SL*RVEILLANCE REQUIREMENTS (Continued) 4.4.6.5 Reports
/#L Following each inservt:e inspection of steam generator tubes, the a.
number of tubes pluggee, repaired or designated F* in each steam generator shall be reported to the Cermission within 15 days of the completion of the :nspe: tion, plugging or repair ef fort.
l b.
The complete results of the steam generator tube and sleeve inservice inspection shall be submitted to the Conadssion in a i
Special Report pursuant to Specification 6.9.2 within 12 months following the completion of the inspection. This Special Report q
shall include:
1.
Number and extent of tubes and sleeves inspected.
2.
Location and percent of wall-thickness penetration for each indication of an imperfection.
l 3.
Identification of tubes plugged or repaired.
c.
Results of steam generator tube inspections which fall into Category C-3 shall be considered a REPORTABLE EVENT and shall be reported pursuant to 10CFR50.73 prior to resumption of plant operation. The written report shall provide a description of investigations conducted to determine the cause of the tube degradation and corrective measures taken to prevent recurrence.
d.
For implementation of the voltage-based repair criteria to tube support plate intersections, notify the staf f prior to returning i
the steam generator to service (Mode 4) should any of the following conditions arise:
1.
If estimated leakage based on the projected end-of-cy:le for i
if not practical, using the actual measured end-of-cyclel voltage distribution exceeds the leak limit (determined f rer the licensing basis dose calculation for the postulated main steam line break) for the next operating cycle.
2.
If circumferential rack-like indications are detected at the tube support plate intersections.
3.
If indicatiens are identified that extend beyond the confines of the tube support plate.
4.
If indications are identified at the tube support plate elevations that are attributable to primary water stress corrosion cracking.
5.
If the calculated conditional burst probability based on the projected end-of-cycle (or if not practical, using the actual measured end-of-cycle) voltage distribution exceeds 1 x 10,
notify the NRC and provide an assessment of the safety significance of the occurrence.
FARLEY-UNIT 2 3/4 4-13a AMENDMENT NO.
M ACTOR COOLANT SYSTEM
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BASES t.
Mechanical 1.
Indications of degradation in the entire length of the sleeve must be evaluated against the sleeve plugging limit.
2.
Indication of tube degradation of any type including a complete guillotine break in the tube between the bottom of the upper joint and the top of the lower roll expansion does not require that the tube be removed from service.
3.
The tube plugging limit continues to apply to the portion of the tube in the entire upper joint region and in the lower roll expansion.
As noted above, the sleeve plugging Itait applies to these areas also.
4.
The tube plugging limit continues to apply to that portion of the tube above the top of the upper joint.
b.
Laser Welded 1.
Indications of degradetion in the length of the sleeve between the weld joints must be evaluated against the sleeve plugging limit.
2.
Indication of tube degradation of any type including a complete break in the tube between the upper weld joint and the lower weld joint does not require that the tube be removed from service.
3.
At the weld joint, degradation must be evaluated in both the sleeve and tube.
i 4.
In a joint with more than one weld, the weld closest to the end of the sleeve represents the joint to be inspected and the limit of the sleeve inspection.
i The tube plugging limit continues to apply to the portion of 5.
the tube above the upper weld joint and below the lower weld
)
joint.
F* tubes do not have to be plugged or repaired provided the remainder of the tube within the tubesheet that is above the F* distance.is not degraded.
distance is equal to 1.7g inches and is measured down from the top of theThe F*
tubesheet or the bottom of the roll transition, whichever is lower in elevation.
Included in this distance is an allowance of 0.25 inch for eddy currint elevation esasurement uncertainty.
Steam generator tube inspections of operating plants have demonstrated the capabiltty to reliably detect wastage type degradation that has penetrated 20%
of the original tube wall thickness.
FARLEV-tmIT 2 B3/4 4-3a AMD O O T NO. 94
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Insert A 12.
F* Tube is a tube:
)
a) with degradation equal to or greater than 40% below the F* distance, and b) which has no indication of imperfecticas greater than or equal to 20% of nominal wall thickness within the F* distance, ~ and c) that remains inservice.
If the above criteria cannot be met, then the L* tube criteria may be applied or the tube must be plugged or repaired.
13.
L* Length is the length of the expanded portion of the tube into the tube sheet from the bottom of the rolled transition or the top of the tube sheet, which ever is lower, that has been measured to be 1.45 inches.
14.
L* Tube: a) is a tube with degradation equal or greater than 40% below the L* 1ength and not degraded within the L*
length; b) the eddy current indication of degradation below J
the L* length must be determined to be the result of cracks j
with an orientation no greater than 15 degrees from axial; c) the L* criteria shall be limited to a maximum of 600 tube j
ends per steam generator; d) tubes qualifying as F* tubes are not classified as L* tubes; e) a minimum ~of 3.1 inches of the tube into the tubesheet from the top of tubesheet or bottom of the rolled transition, which ever is lower, shall be inspected using rotating pancake coil eddy current technique or an inspection method shown to give equivalent or better information on the orientation and length of axial cracksi f) a minimum aggregate measured length of 2.07 inches of sound roll expansion; g) a maximum measured crack length of.39 inches; h) a maximum of 5 distinct indications with a single band of tube degradation; and 1) that remains
.in service.
Insert B L* is similar to F*; however, bands of axial degradation are allowed as long as sufficient non-degraded tubing is available to ensure structural i
and leakage integrity.
Provide below is the Unit 2 Cycle 11 specific L*
l criterion:
Unit 2 Cycle 11 Specific L* Criterion Parameter Value Minimum distance of SRE 2.07 inches (measured)
Maximum number of distinct degradation areas in a band 5
Maximum inclination angle of single band 15 degrees (measured)
Maximum crack length
.39 inches (measured)
Minimum distance of SRE from the bottom of the transition 1.45 inches (measured) roll to the top of the indication j