ML112990471

Discussion Points for Call Fall 2011 RFO - Steam Generator Inspection

ML112990471
Person / Time
Site:	Arkansas Nuclear
Issue date:	10/25/2011
From:	Clark R Entergy Operations
To:	Kalyanam N Plant Licensing Branch IV
Kalyanam N, NRR/DLPM, 415-1480
Shared Package
ML112990340	List: ML112990371 ML112990418 ML112990471 ML112990527
References
TAC ME7368
Download: ML112990471 (5)

Text

C:\FileNET\ML112990471.doc ANO-1 STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS October 25, 2011 The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator tube inspections to be conducted during the mid-outage call during the, Unit 1 refueling outage (1R23). This conference call is scheduled to occur towards the end of the planned SG tube inspections, but before the unit completes the inspections and repairs.

1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

No indication of primary-to-secondary leakage present prior to the current refueling outage (1R23). Typical Tritium values are ~ 0.4 gallons per day.

ANO1 Primary to Secondary Leakage 2011 2

H3 GPD 1 A N-16 B N-16 0

11/3/10 12/3/10 1/3/11 2/3/11 3/3/11 4/3/11 5/3/11 6/3/11 7/3/11 8/3/11 9/3/11 10/3/11 11/3/11 Date

2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.

No secondary side pressure tests have been performed or scheduled for 1R22.

3. Discuss any exceptions taken to the industry guidelines.

No exceptions were taken to NEI 97-06 and EPRI Steam Generator Guidelines.

4. For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, Page 1 of 5

C:\FileNET\ML112990471.doc expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100% of dents/dings greater than 5 volts and a 20% sample between 2 and 5 volts), and the expansion criteria.

The 1R23 Steam Generator Examination is being performed to validate the extent of tie-rod bowing and tube support plate wear. ANO-1 has operated for one cycle with respect to inspecting tie rod bowing and two cycles for tube support plate wear. Tie-rod bowing was previously identified and entered into Entergys Corrective Action Program as CR-ANO 2007-00959.

BOBBIN EXAMINATION:

All in-service tubes were examined full length (UTE-LTE) with the standard bobbin coil technique, using dual guide tubes. Additional tubes to be inspected full length include those tubes that are affected by bowed tie rods with the X-probe. The primary probe utilized for this examination will be the 0.510 multi-frequency (M/ULC) bobbin probe (510UL).

SG A - 100% Tubes SG B - 100% Tubes SPECIAL INTEREST EXAMINATION:

The following code categories identified during the bobbin coil examination will require subsequent diagnostic testing with X-probe.

1. I-Code indications identified with Bobbin.

2. New Wear Indications identified with Bobbin > 10% through wall.

3. Any further indications as identified by lead analysis personnel or customer representatives.

1. of Area Inspected Exam Type Probe Used OTSG Expansion Inspections Full Length 100% Full 0.510 A 15135 None Tubing Length Bobbin Full Length 100% Full 0.510 B 15591 None Tubing Length Bobbin Special Interest Tie Rods X-Probe A 452 None Special Interest Tie Rods X-Probe B ~ 51 None Additionally, the Plus Point was used as a diagnostic for the two tubes identified in SGA with mid-span and bulge indications.

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C:\FileNET\ML112990471.doc PLUG VISUAL EXAMINATION:

All plugs in the Inlet and Outlet channel heads will be visually examined to verify tube plug location and potential leaking plugs.

Current Plugged Tubes SG- A 10 plugged tubes SG- B 6 plugged tubes

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide a summary of the number of indications identified to-date for each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications at the expansion transition). For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

SG ID Wear 1-19% Wear 20-39% Wear 40-100% Proximity SGA 1471 36 0 56 SGB 1352 68 2 19 Largest Wear was in SGB at 46%

Affected Tie Rods SGA = 12 SGB = 7 Extent of Bowing (maximum lateral extent)

SGA = 1.3 inches SGB = 0.5 inches Tube Integrity was maintained for previous cycle for all degradation mechanisms.

6. Describe repair/plugging plans.

Plugging for Wear - 3 cycle interval - plug down to 35%

SGA = 0 SGB = 7 Plugging for Tie Rod Bowing Page 3 of 5

C:\FileNET\ML112990471.doc SG A = 3 SG B = 2 Note - all plugged locations are being stabilized (full length)

7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).

None - No indications exceeded screening criteria have been identified to date.

8. Discuss the following regarding loose parts:

what inspections are performed to detect loose parts No visual inspections. 100% bobbin only - No loose parts identified - 4 Potential Loose Parts that are historic and have been tracked since replacement.

a description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known)

None if the loose parts were removed from the SG None indications of tube damage associated with the loose parts None

9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessing deposit loading, etc).

During 1R23 there were no secondary side inspections planned or conducted.

10. Discuss any unexpected or unusual results.

The following were issues identified during the recent inspection that have not been identified previously

1. SGA - two tubes had mid-span indications where the adjacent tie rod/tube have been in contact. The indications were tested with the bobbin, X-probe and Plus Point. It was determined that the indications were not associated with wall loss but rather a surface anomaly possibly from multiple bowing of the tubes. These were surface issues only estimated at 1 mil of thickness. The estimated burst pressure is equivalent to virgin tubes.

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C:\FileNET\ML112990471.doc

2. SG B - discovery of tie rod bowing. [Entered into the Corrective Action Program CR-ANO-1-01925]. Multi-directional issue.

Currently we are evaluating performing a diagnostic inspection during 1R24 to monitor bowing conditions.

11. Provide the schedule for steam generator-related activities during the remainder of the current outage.

4/25 - Complete SG B Repairs 4/26 - Complete SG A Repairs 4/26 - Bowl Close outs, then following Core Offload, ND removal during Off-load window.

12. Tie Rod Bowing Results Page 5 of 5