Event Notification Report for March 11, 2000
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/10/2000 - 03/11/2000
EVENT NUMBERS
36788
Power Reactor
Event Number: 36788
Facility: TURKEY POINT
Region: 2 State: FL
Unit: [3] [] []
RX Type: [3] W-3-LP,[4] W-3-LP
NRC Notified By: DEAL
HQ OPS Officer: BOB STRANSKY
Region: 2 State: FL
Unit: [3] [] []
RX Type: [3] W-3-LP,[4] W-3-LP
NRC Notified By: DEAL
HQ OPS Officer: BOB STRANSKY
Notification Date: 03/11/2000
Notification Time: 16:07 [ET]
Event Date: 03/11/2000
Event Time: 14:30 [EST]
Last Update Date: 03/22/2000
Notification Time: 16:07 [ET]
Event Date: 03/11/2000
Event Time: 14:30 [EST]
Last Update Date: 03/22/2000
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(i) - DEG/UNANALYZED COND
10 CFR Section:
50.72(b)(2)(i) - DEG/UNANALYZED COND
Person (Organization):
EDWARD MCALPINE (R2)
EDWARD MCALPINE (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | N | N | 0 | Refueling | 0 | Refueling |
DEFECT DETECTED DURING EDDY CURRENT INSPECTION OF STEAM GENERATOR
"Turkey Point is performing eddy current testing of the Unit 3 steam generators in accordance with Plant Technical Specifications and Industry Guidance. A 20% inspection was planned for the top of tubesheet expansion transition region in the hot leg of each steam generator. This total planned sample was divided into 1st, 2nd and 3rd samples to address the progressive inspection process of the Technical Specifications Table 4.4-2. The 1st sample of 96 tubes in the 3B steam generator resulted in detection of 1 defect near the top of the tubesheet. In accordance with Technical Specification 4.4.5.5c, this defect results in a C-3 Classification for the 1st sample.
"A small number of additional indications near the top of the tubesheet have also been detected in this steam generator, and the inspection is ongoing. The inspection will be expanded to 100% of the tubes in the 3B steam generator.
"Eddy current results indicate the defects are shallow volumetric or pit-like in nature. A preliminary structural evaluation indicates that all indications detected to date meet the structural and leakage integrity performance criteria of NEI 97-06, 'Steam Generator Program Guidelines.'"
The NRC resident inspector has been informed of this notification by the licensee.
* * * UPDATE 1537 3/22/2000 FROM MOWREY TAKEN BY STRANSKY * * *
"The steam generator inspection effort at Turkey Point Unit 3 was completed on March 16, 2000. The scope of inspection was expanded to 100% of the hot leg top of tubesheet for all three steam generators. Scope expansion for the 3B steam generator was driven by Technical Specification requirements. Scope expansion for the 3A steam generator was driven by the performance criteria contained in NEI 97-06, 'Steam Generator Program Guidelines.' Scope expansion in the 3C steam generator was pursued as a prudent measure due to the results in the 3A and 3B steam generators.
"The total number of tubes plugged during this inspection were as follows:
"3A SG: 7 tubes for ID circumferential indications, 3 tubes for OD circumferential indications, 13 tubes for OD volumetric indications and 2 tubes for wear indications. Total of 25 tubes plugged.
"3B SG: 2 tubes for ID circumferential indications, 3 tubes for OD circumferential indications, 22 tubes for OD volumetric indications and 1 wear indications. Total of 28 tubes plugged.
"3C SG: 6 tubes for ID circumferential indications, 2 tubes for OD circumferential indications, 6 tubes for OD volumetric indications and 2 wear indications. Total of 16 tubes plugged.
"An investigation has been conducted to determine the cause of the tube degradation identified during this inspection. This investigation included a review of the steam generator design features, manufacturing information, inspection techniques, and historical and current chemistry programs. Due to the lack of prior inspection data, and the limited number of defects identified by the industry for thermally treated alloy 600 tubing, the results are inconclusive for the circumferential and volumetric indications. The potential causes for these mechanisms are suspected to be original manufacturing anomalies, inspection anomalies, or corrosion attack. The number of indications found is attributed to an inspection transient resulting from first time extended use of rotating probe technology at Turkey Point.
"The corrective measures taken to prevent recurrence of the potential causes of degradation are as follows:
"* The inspection was expanded to cover 100% of the hot leg areas affected by the circumferential and volumetric indications in order to provide a complete baseline with the rotating probe technology.
"* The chemistry program is continually reviewed for enhancement opportunities and compliance with the latest industry guidance. Turkey Point has initiated the addition of ethanolamine (ETA) to reduce iron transport to the steam generators.
"* Aggressive sludge removal techniques have been incorporated including high volume bundle flushing.
"* The latest industry inspection guidelines will continue to be implemented, to ensure adequate inspections are conducted.
"Mechanical wear indications have been tracked for Turkey Point Unit 3 since the fourth cycle of operation for the current steam generators (1990). The cause of this type of degradation is a well understood design issue. Tubes with wear indications were plugged based on qualified sizing techniques. Tubes plugged for mechanical wear were not the cause of the 10CFR50.72 notification."
The NRC resident inspector has been informed of this update by the licensee. Notified R2DO (Decker).
"Turkey Point is performing eddy current testing of the Unit 3 steam generators in accordance with Plant Technical Specifications and Industry Guidance. A 20% inspection was planned for the top of tubesheet expansion transition region in the hot leg of each steam generator. This total planned sample was divided into 1st, 2nd and 3rd samples to address the progressive inspection process of the Technical Specifications Table 4.4-2. The 1st sample of 96 tubes in the 3B steam generator resulted in detection of 1 defect near the top of the tubesheet. In accordance with Technical Specification 4.4.5.5c, this defect results in a C-3 Classification for the 1st sample.
"A small number of additional indications near the top of the tubesheet have also been detected in this steam generator, and the inspection is ongoing. The inspection will be expanded to 100% of the tubes in the 3B steam generator.
"Eddy current results indicate the defects are shallow volumetric or pit-like in nature. A preliminary structural evaluation indicates that all indications detected to date meet the structural and leakage integrity performance criteria of NEI 97-06, 'Steam Generator Program Guidelines.'"
The NRC resident inspector has been informed of this notification by the licensee.
* * * UPDATE 1537 3/22/2000 FROM MOWREY TAKEN BY STRANSKY * * *
"The steam generator inspection effort at Turkey Point Unit 3 was completed on March 16, 2000. The scope of inspection was expanded to 100% of the hot leg top of tubesheet for all three steam generators. Scope expansion for the 3B steam generator was driven by Technical Specification requirements. Scope expansion for the 3A steam generator was driven by the performance criteria contained in NEI 97-06, 'Steam Generator Program Guidelines.' Scope expansion in the 3C steam generator was pursued as a prudent measure due to the results in the 3A and 3B steam generators.
"The total number of tubes plugged during this inspection were as follows:
"3A SG: 7 tubes for ID circumferential indications, 3 tubes for OD circumferential indications, 13 tubes for OD volumetric indications and 2 tubes for wear indications. Total of 25 tubes plugged.
"3B SG: 2 tubes for ID circumferential indications, 3 tubes for OD circumferential indications, 22 tubes for OD volumetric indications and 1 wear indications. Total of 28 tubes plugged.
"3C SG: 6 tubes for ID circumferential indications, 2 tubes for OD circumferential indications, 6 tubes for OD volumetric indications and 2 wear indications. Total of 16 tubes plugged.
"An investigation has been conducted to determine the cause of the tube degradation identified during this inspection. This investigation included a review of the steam generator design features, manufacturing information, inspection techniques, and historical and current chemistry programs. Due to the lack of prior inspection data, and the limited number of defects identified by the industry for thermally treated alloy 600 tubing, the results are inconclusive for the circumferential and volumetric indications. The potential causes for these mechanisms are suspected to be original manufacturing anomalies, inspection anomalies, or corrosion attack. The number of indications found is attributed to an inspection transient resulting from first time extended use of rotating probe technology at Turkey Point.
"The corrective measures taken to prevent recurrence of the potential causes of degradation are as follows:
"* The inspection was expanded to cover 100% of the hot leg areas affected by the circumferential and volumetric indications in order to provide a complete baseline with the rotating probe technology.
"* The chemistry program is continually reviewed for enhancement opportunities and compliance with the latest industry guidance. Turkey Point has initiated the addition of ethanolamine (ETA) to reduce iron transport to the steam generators.
"* Aggressive sludge removal techniques have been incorporated including high volume bundle flushing.
"* The latest industry inspection guidelines will continue to be implemented, to ensure adequate inspections are conducted.
"Mechanical wear indications have been tracked for Turkey Point Unit 3 since the fourth cycle of operation for the current steam generators (1990). The cause of this type of degradation is a well understood design issue. Tubes with wear indications were plugged based on qualified sizing techniques. Tubes plugged for mechanical wear were not the cause of the 10CFR50.72 notification."
The NRC resident inspector has been informed of this update by the licensee. Notified R2DO (Decker).