ML20079J666
| ML20079J666 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 12/17/1982 |
| From: | ARKANSAS POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20079J661 | List: |
| References | |
| NUDOCS 8212280309 | |
| Download: ML20079J666 (5) | |
Text
4.18 STEAM GENERATOR TUBING SURVEILLANCE Applicability Applies to the surveillance of tubing of each steam generator.
Objective To ensure integrity of the steam generator tubing through a defined inservice surveillance program, and to minimize exposure of personnel to radiation during performance of the survillance program.
4.18.1 Baseline Inspection The first steam generator tubing inspection performed according to Specifications 4.18.2 and 4.18.3.a shall be considered as constituting the baseline condition for subsequent inspections.
- 4. ~.B. 2 Examination Methods Inservice inspection of steam generator tubing shall include non-destructive examination by eddy-current testing or other equivalent techniques.
The inspection equipment shall provide a sensitivity that will detect defects with a penetration of 20 percent or more of the minimum allowable as-manufactured tube wall thickness.
4.18.3 Selection and Testing The steam generator sample size is specified in Table 4.18.1 The steam generator tube minimum sample size, inspection result classification, and the corresponding action required shall be as specified in Table 4.18.2.
The inservice inspection of steam generator tubes shall be performed at the frequencies specified in Specification 4.18.4 and the inspected tubes shall be verified acceptable per the acceptance criteria of Specification 4.18.5 The tubes selected for each inservice inspection shall include at least 3% of the total number of tubes in both steam generators; the tubes selected for these inspections shall be selected on a random basis except:
a.
The first sample inspection during each inservice inspection (subsequent to the baseline inspection) of each steam generator shall include:
1.
All nonplugged tubes that previously had detectable wall penetrations (>20%), and 2.
At least 50% of the tubes inspected shall be in those areas where experience has indicated potential problems.
A tube inspection (pursuant to Specification 4.18.5.a.8) shall be performed on each selected tube.
If any selected tube does not permit the passage of the eddy current probe for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection.
8212280309 821217 PDR ADOCK 05000313 110].
P PDR Amendment No.
b.
Tubes in the following groups may be excluded from the random sample in Specification 4.18.3.a if all tubes in the group in both steam generators are inspected.
No credit will be taken for these tubes in i
meeting minimum sample size requirements.
(1) Group A-1:
Tubes within one, two or three rows of the open l
inspection lane.
(2) Group A-2: Tubes having a drilled opening in the 15th tube support plate.
(3) Group A-3: Tubes in an area adjacent to Group A-1 where experience indicates potential problems.
The area shall be bounded by at least five rows of non-defective tubes away from the lane and five columns of non-defective tubes toward the center of the bundle.
The initial inspection sample in a refueling outage shall include at least the region of tubes inspected in the previous refueling outage.
The inspection of tubes in the above groups may be limited to those portions of the tubes where imperfections or defects are expected to occur.
c.
The second and third sample inspections during each inservice inspection as required by Table 4.18.2 may be less than a full tube inspection by concentrating the inspection on those areas of the tube sheet array and on those portions of the tubes where tubes with imperfections were previously found.
The results of each sample inspection shall be classified into one of the following three categories:
Cg,agory Inspection Results C-1 Less than 5% of the total tubes inspected are degraded tubes and none of the inspected tubes are defective.
C-2 One or more tubes, but not more than 1% of the total tubes inspected are defective, or between 5% and 10% of the total tubes inspected are degraded tubes.
C-3 More than 10% of the total tubes inspected are degraded tubes or more than 1% of the inspected tubes are defective.
NOTES:
(1)
In all inspections, previously degraded tubes must exhibit significant (>10%) further wall penetrations to be included in the above percentage calculations.
110k Amendment No.
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(2) Where special inspections are performed pursuant to 4.18.3.b, defective or_ degraded tubes found as a result of l
l the inspection shall be included in determining the Inspection Results Category for that special inspection but need not be included in determining the Inspection Results Category for the general steam generator inspection.
4.18.4 Inspection Intervals The above required inservice inspections of steam generator tubes shail be performed at the following frequencies:
a.
The baseline inspection shall be performed during the first refueling shutdown.
Subsequent inservice inspections shall be performed at intervals of not less than 10 nor more than 24 calendar months after the previous inspection.
If the results of two consecutive inspections for a given group
- of tubes following service under a'.'
volatile treatment (AVT) conditions fall into the C-1 category or if two consecutive inspections demonstrate that previously observed 7
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degradation has not continued and no additional degradation has occurred, the inspection interval for that group may be extended to a maximum of 40 months.
b.
If the results of the inservice inspection of a steam generator performed in accordance with Table 4.18.2 at 40 month intervals for a given group
- of tubes fall in Category C-3, subsequent inservice inspections shall be performed at intervals of not less than 10 nor more than 20 calendar months after the previous inspection.
The increase in inspection frequency shall apply until a subsequent inspection meets the conditions specified in 4.18.4.a and the interval can be extended to 40 months.
c.
Additional, unscheduled inservice inspections shall be performed on each steam generator in accordance with the first sample inspection specified in Table 4.18.2 during the shutdown subsequent to any of the following conditions:
1.
Primary-to-secondary leakage in excess of the limits of Specification 3.10 (inservice inspection not required if leaks originate from tube-to-tube sheet welds),
2.
A seismic occurence greater than the Operating Basis Earthquake, 3.
A loss-of-coolant accident requiring actuation of the engineered safegards, or 4.
A main steam line or feedwater line break.
4.18.5 Acceptance Criteria a.
1.
Imperfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication drawings or specifications.
Eddy-current testing indications below 20% of the nominal tube wall tickness, if detectable, may be considered as imperfections.
2.
Degradation means a service-induced cracking, wastage, wear or general corrosion occuring on either the inside or outside of a tube.
3.
Degraded Tube means a tube containing imperfections 2 20% of the nominal wall thickness caused by degradation.
4.
% Degradation means the percentage of the tube wall thickness affected or removed by degradation.
5.
Defect means an imperfection of such severity that it exceeds the plugging limit.
A tube containing a defect is defective.
"A group of tubes means: (a) All tubes inspected pursuant to 4.18.3.b, or l
(b) All tubes in a steam generator less those inspected pursuant to 4.18.3.b.
l 1101 Amendment No.
TABLE 4.18-2 STEAM GENERATOR TUBE INSPEC110N (2)
Ig ist SAMPLE INSPECTION 2nd SAMPLE INSPECTION 3RD SAMPLE INSPECTION SAMPLE SIZE RESULT ACTION REQUIRED RESULT ACTION REQUIRED RESULT ACTION REQUIRED m
ce g
A minimum of S C-1 NONE N/A N/A N/A N/A
)
Tubes per S.G C-2 Plug defective tubes C-1 NONE N/A N/A and Inspect addi-tional 2S tubes in C-2 Plug defective C-1 NONE this S. G.
tubes and Inspect C-2 Plug defective tubes additional 45 tubes in this S. G.
C-3 Perform action for C-3 result of first sample C-3 Perform action for C-3 result of first N/A N/A sample hh C-3 Inspect all tubes in other O
this S.
G., plug S. G. is NONE N/A N/A defective tubes and C-1 inspect 2S tubes in Other Perform action for other S.G.
S. G.
is C-2 result of A
/A C-2 second sample Prompt notification to NRC pursuant to specification Other Inspect all tubes in 6.12.3 S. G. is each S. G. and plug C-3 defective tubes.
Prompt notification N/A N/a to NRC pursuant to specification 6".12.3 l
bh3les:
(1) S = 3f % Where N is the number of steam generators in the unit, and n is the number of steam generators inspected during an -inspection.
(2) For tubes inspected pursuant to 4.18.3.b:
No action is, required for C-1 results.
For C-2 results in one l
or both steam generators plug defective tubes.
For C-3 results in one er both steam generators, plug defective tubes and provide prompt notification of NRC pursuant to specification 6.12.3.
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