ML042810515
| ML042810515 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/05/2004 |
| From: | Colburn T NRC/NRR/DLPM |
| To: | |
| References | |
| TAC MC1857 | |
| Download: ML042810515 (3) | |
Text
REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued)
- 2.
Tubes in those areas where experience has indicated potential problems, and
- 3.
Except for Alloy 800 leak limiting sleeves, at least 3 percent of the total number of sleeved tubes in all three steam generators.
A sample size less than 3 percent is acceptable provided all the sleeved tubes in the steam generator(s) examined during the refueling outage are inspected.
All inservice Alloy 800 leak limiting sleeves shall be inspected over the full length using a plus point coil or equivalent qualified technique during each refueling outage.
These inspections will include both the tube and the sleeve, and
- 4.
A tube inspection pursuant to Specification 4.4.5.4.a.8.
If any selected tube does not permit the passage of the eddy current probe for a tube or sleeve inspection, this shall be recorded and an adjacent tube shall -be selected and subjected to a tube inspection.
- 5.
Indications left in service as a result of application of the tube support plate voltage-based repair criteria (4.4.5.4.a.10) shall be inspected by bobbin coil probe during all future refueling outages.
- c.
The tubes selected as the second and third samples (if required by Table 4.4-2) during each inservice inspection may be subjected to a partial tube inspection provided:
- 1.
The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previously found, and
- 2.
The inspections include those portions of the tubes where imperfections were previously found.
- d.
Implementation of the steam generator tube-to-tube support plate repair criteria requires a 100-percent bobbin coil inspection for hot-leg and cold-leg tube support plate intersections down to the lowest cold-leg tube support plate with known outside diameter stress corrosion cracking (ODSCC) indications.
The determination of the lowest cold-leg tube support plate intersections having ODSCC indications shall be based on the performance of at least a 20-percent random sampling of tubes inspected over their full length.
The results of each sample inspection shall be classified into one of the following three categories:
BEAVER VALLEY -
UNIT 1 3/4 4-9 Amendment No. 260
REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued)
- 6.
Plugging or Repair Limit means the imperfection depth at or beyond which the tube shall be removed from service by plugging or repaired by sleeving in the affected area because it may become unserviceable prior to the next inspection.
The plugging or repair limit imperfection depths are specified in percentage of nominal wall thickness as follows:
a)
Original tube wall 40%
This definition does not apply to tube support plate intersections for which the voltage-based repair criteria are being applied.
Refer to 4.4.5.4.a.10 for the repair limit applicable to these intersections.
b)
ABB Combustion Engineering TIG welded sleeve wall 32%
c)
Westinghouse laser welded sleeve wall 25%
d)
Westinghouse Alloy 800 leak limiting sleeve*:
Plug on detection of any service induced imperfection, degradation or defect in the (a) sleeve and/or (b) pressure boundary portion of the original tube wall in the sleeve/tube assembly (i.e., the sleeve-to-tube joint).
- 7.
Unserviceable describes the condition of a tube if it leaks or contains a defect large enough to affect its structural integrity in the event of an Operating Basis Earthquake, a loss-of-coolant accident, or a steamline or feedwater line break as specified in 4.4.5.3.c, above.
- 8.
Tube Inspection means an inspection of the steam generator tube from the point of entry (hot-leg side) completely around the U-bend to the top support to the cold-leg.
- 9.
Tube Repair refers to sleeving which is used to maintain a tube in-service or return a tube to service.
This includes the removal of plugs that were installed as a corrective or preventive measure.
The following sleeve designs have been found acceptable:
a)
ABB Combustion Engineering TIG Welded Sleeves, CEN-629-P, Revision 02 and CEN-629-P Addendum 1.
b)
Westinghouse laser welded sleeves, WCAP-13483, Revision 1.
- Applicable only to Cycle 17.
BEAVER VALLEY -
UNIT 1 3/4 4-10b Amendment No.260
REACTOR COOLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued) c)
Westinghouse Alloy 800 leak limiting sleeves, WCAP-15919-P, Revision 00.*
- 10.
Tube Support Plate Plugging Limit is used for the disposition of an alloy 600 steam generator tube for continued service that is experiencing predominantly axially oriented outside diameter stress corrosion cracking confined within the thickness of the tube support plates.
At tube support plate intersections, the plugging (repair) limit is based on maintaining steam generator tube serviceability as described below:
a)
- tubes, whose degradation is attributed to outside diameter stress corrosion cracking within the bounds of the tube support plate with bobbin voltages less than or equal to 2.0 volts will be allowed to remain in service.
b)
- tubes, whose degradation is attributed to outside diameter stress corrosion cracking within the bounds of the tube support plate with a bobbin voltage greater than 2.0 volts will be repaired or plugged, except as noted in 4.4.5.4.a.10.c below.
c)
- tubes, with indications of potential degradation attributed to outside diameter stress corrosion cracking within the bounds of the tube support plate with a bobbin voltage greater than 2.0 volts but less t an or equal to the upper voltage repair limit may remain in service if a rotating pancake coil or acceptable alternative inspection does not detect degradation.
Steam generator tubes, with indications of outside diameter stress corrosion cracking degradation with a bobbin voltage greater than the upper voltage repair limit will be plugged or repaired.
d)
If an unscheduled mid-cycle inspection is performed, the following mid-cycle repair limits apply instead of the limits identified in 4.4.5.4.a.10.a, 4.4.5.4.a.10.b, and 4.4.5.4.a.10.c.
- Applicable only to Cycle 17.
(1) The upper voltage repair limit is calculated according to the methodology in Generic Letter 95-05 as supplemented.
BEAVER VALLEY - UNIT 1 3/4 4-10c Amendment No. 260