ML103060087
| ML103060087 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/29/2010 |
| From: | Severance S Duke Energy Carolinas |
| To: | Office of Nuclear Reactor Regulation, NRC/RGN-II |
| References | |
| 46375 | |
| Download: ML103060087 (4) | |
Text
ýJbI2912010 U.S. Nuclear Regulatory Commission Operations Center Event Report Power Reactor Event#
46375 Site: OCONEE Notification Date/Time: 10/29/2010 09:39 (EDT)
Unit: 1 2
3 Region: 2 State : SC Event Date / Time: 10/28/2010 12:40 (EDT)
Reactor Type: [1] B&W-L-LP,[2] B&W-L-LP,[3] B&W-L-LP Last Modification: 10/29/2010 Containment Type: DRY AMB DRY AMB DRY AMB NRC Notified by: SANDRA SEVERANCE Notifications: REBECCA NEASE R2DO HQ Ops Officer: BILL HUFFMAN PT 21 GROUP E-MAIL Emergency Class: NON EMERGENCY 10 CFR Section:
21.21 UNSPECIFIED PARAGRAPH Unit Scram Code RX Crit i Init Power I Initial RX Mode Curr Power Current RX Mode 1
N Yes 100 Power Operation 100 Power Operation 2
N Yes i 100 Power Operation
- 100 Power Operation 3
N No 0
Refueling
'0 Refueling DEFECT DISCOVERED IN TUBE STEEL THAT COULD BE USED IN VARIOUS SAFETY RELATED STRUCTUAL APPLICATIONS "On October 28, 2010, Duke Energy completed a reportability determination which concluded that a defect associated with four inch by four inch tube steel with one-half inch wall thickness is reportable under Part 21. The tube steel was procured safety-related from Mackson, Inc. on May 26, 2010. Receipt of the material occurred on June 14, 2010. During construction of the Protected Service Water (PSW) ductbank elevated cable raceway, Craft reported a longitudinal crack in the tube steel, approximately four feet in length, adjacent to a raceway fabrication weld. The crack was located in the manufacturer's longitudinal seam weld in the tube steel. Follow-up investigation and laboratory evaluation revealed that the structural steel tubing in question contains surface breaking flaws located along the centerline of the seam weld which are attributable to lack of fusion that occurred during tubing manufacture. Additional testing of samples from the same heat of material indicated that the seam weld flaw depth varied with some localized areas reaching depths of at least 40 percent through the wall thickness prior to raceway fabrication welding. According to documents received from the supplier, during dedication, the supplier performed chemical, physical and 100 percent visual exam in accordance with their accepted dedication procedures for ASTM A500 for Grade B material. However, the supplied product did not conform to the requirements of ASTM A500 in that the longitudinal butt joint was not welded across its thickness (Reference ASTM A500, Section 6.2).
Duke Energy will provide follow-up written notification within 30 days pursuant to Part 21.21(d)(3)(ii).
"Initial Safety Significance: None. The defective tube steel utilized in the PSW structure was not placed into service. Tube steel sections of the same heat of material not used in pre-fabrication efforts were scrapped. Those installed were cut out or evaluated for acceptability by Engineering. The failure of this weld significantly impairs the structural properties of the hollow structural section. The generic implications associated with the potential to use these structural members in various nuclear safety-related applications at this site and at other stations results in a substantial safety hazard were it to remain uncorrected.
10/29/2010 Power Reactor U.S. Nuclear Regulatory Commission Operations Center Event Report Event#
46375 "Corrective Action(s):
- 1. Notified supplier, Mackson, Inc.
- 2. Re-worked all uses of the defective structural tube steel.
- 3. Developed additional, required testing for safety -related tube steel."
The supplier (Mackson, Inc) indicated to Oconee that no other nuclear power plants have received this type of tube steel from Mackson. Oconee also has concluded that the condition is confined to only one heat of the tubing used onsite. All the tube steel of this heat has been either disposed of, removed, or verified acceptable.
The licensee has notified the NRC Resident Inspector.
10/29/10 09:40 FAX 2869 UNIT 1 & 2 CONTROL ROOhl
-ý NRC Z 001 Attachment B NRC Event Notification Worksheet OMP 1-14 Page 1 of 2 NRC Event Notification Worksheet Notification Time Facility or 0Oanization Unit Caller's Name Call Back #
Oconee Nuclear Station 1, 2, 3 Sandra Severance ENS 256-9931 (864) 873-3466 NRC Operations Officer Contacted:
I NRC Event Number:
Event Time/Zone Event Date Power/Mode Before Power/Mode After 1240 EST 10/28/2010 N/A N/A Event Classifications El General Emergency El Site Area Emergency L] Alert LI Unusual Event Li 50.72 Non-emergency (see other columns)
Li 72.75 Spent Fuel (ISFSI)
El 73.71 Physical Security EL Transportation
[] 20.2202 Material/Exposure L] 26.73 Fitness for Duty N
Other: Part 21.21(d)(3)(i) 1-Hour Non-emergency 10 CFR 50.72 (b)(1)
Li Deviation from TS per 50.54(x) 4-Hour Non-Emergency 10 CFR 50.72 (b)(2)
E] (i) TS Required Shutdown E] (iv) (A) ECCS Discharge into RCS Li (iv) (B) RPS Actuation (while critical)
L] (xi) News release/notification to other government agencies I
8-Hour Non-Emergency 10 CFR 50.72 (b) (3)
Li (ii) (A) Degraded Condition Li (ii) (B) Unanalyzed Condition Li (xiii) Loss of emergency assessment capability/offsite communications L] (iv) (A) System Actuation F] RPS EL Containment isolation Li ECCS L] EFW EL Containment spray/coolers L L Emergency AC (Keowee Hydro)
(v) (A) Safe Shutdown Capability L] (v) (B) Residual Heat Removal Capability Li (v) (C) Control of radiological material L] (v) (D) Accident Mitigation Li (xii) Transport contaminated person to offsite medical facility Event Description (Include systems affected, actuations and their initiating signals, causes, effect of event on plant, actions taken or planned, etc.)
10/29/10 09:41 FAX 2869 UNIT 1 & 2 CONTROL ROOM NRC R002 Attachment B NRC Event Notification Worksheet OMP 1-14 Page 2 of 2 Event: On October 28, 2010, Duke Energy completed a reportability determination which concluded that a defect associated with four inch by four inch tube steel with one-half inch wall thickness is reportable under Part 21. The tube steel was procured safety-related from Mackson, Inc. on May 26, 2010. Receipt of the material occurred on June 14, 2010. During construction of the Protected Service Water (PSW) ductbank elevated cable raceway, Craft reported a longitudinal crack in the tube steel, approximately four feet in length, adjacent to a raceway fabrication weld. The crack was located in the manufacturer's longitudinal seam weld in the tube steel. Follow-up investigation and laboratory evaluation revealed that the structural steel tubing in question contains surface breaking flaws located along the centerline of the seam weld which are attributable to lack of fusion that occurred during tubing manufacture. Additional testing of samples from the same heat of material indicated that the seam weld flaw depth varied with some localized areas reaching depths of at least 40 percent through the wall thickness prior to raceway fabrication welding. According to documents received from the supplier, during dedication, the supplier performed chemical, physical and 100 percent visual exam in accordance with their accepted dedication procedures for ASTM A500 for Grade B material. However, the supplied product did not conform to the requirements of ASTM A500 in that the longitudinal butt joint was not welded across its thickness (Reference ASTM A500, Section 6.2). Duke Energy will provide follow-up written notification within 30 days pursuant to Part 21.21(dX3)(ii).
Initial Safety Significance: None. The defective tube steel utilized in the PSW structure was not placed into service.
Tube steel sections of the same heat of material not used in pre-fabrication efforts were scrapped. Those installed were cut out or evaluated for acceptability by Engineering. The failure of this weld significantly impairs the structural properties of the hollow structural section. The generic implications associated with the potential to use these structural members in various nuclear safety-related applications at this site and at other stations results in a substantial safety hazard were it to remain uncorrected.
Corrective Action(s):
- 1. Notified supplier, Mackson, Inc.
- 2. Re-worked all uses of the defective structural tube steel.
- 3. Developed additional, required testing for safety-related tube steel.
Anything unusual or not understood?
El-Yes (Explain above)
I No Did all systems function as required?
Yes D No (Explain above)
Mode of operations until corrected: N/A Estimated restart date: N/A Does event result in a radiological release, RCS leak, or steam generator tube I D Yes (complete page 3) 1 No Ileak?
Does the event result in any of the units experiencing a El Yes (complete Oconee Plant Status sheet)
] No transient?
Notifications NRC Resident:ir.
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