ENS 52487
ENS Event | |
|---|---|
05:00 Jan 12, 2017 | |
| Title | Part 21 Interim Report - Excess Material Condition on the Casing for the Ap1000 Reactor Coolant Pump |
| Event Description | The following summary was excerpted from report #EMD-GM-17-02, provided by the Curtis-Wright Electro-Mechanical Corporation:
Curtiss-Wright Electro-Mechanical Corporation (CW-EMD) has identified a condition which is currently being evaluated to determine if a significant safety hazard exists in the casing for the AP1000 Reactor Coolant Pump (RCP). The investigation is underway, but will not be completed within the required 60 days from discovery as required by paragraph 21.21(a)(1) of the regulation. This submission constitutes CW-EMD's interim report on the condition in accordance with paragraph 21.21(a)(2) of the regulation. Casings for the AP1000 Reactor Coolant Pump. The casings have an excess material condition in the transition region between the cast bowl and the suction nozzle. The condition is a discontinuous (non-tangential) axisymmetric feature between the cast bowl region and machined suction nozzle OD. The as-built transition feature on the casings has not been analyzed and is not included in CW-EMD Engineering Memorandum 7242, Revision 1, Volume 1, which is the applicable generic design report for the AP1000 RCP casing and main closure. At present, the following domestic deliveries have been made: - 8 casings have been provided to V.C. Summer Units 2 and 3. - 8 casings have been provided to Vogtle Units 3 and 4. Name and address of the individual or individuals informing the Commission: Brian W. Eckels, General Manager Curtiss-Wright Electro-Mechanical Corporation 1000 Wright Way Cheswick, Pa 15024
The following update was received via email: Curtiss-Wright Electro-Mechanical Corporation (CW-EMD) submitted an interim report concerning a deviation in the AP1000 Reactor Coolant Pump casing via letter EMD-GM-17-02, dated January 12, 2017. This letter updates the status of the investigation. 1. Extent of condition evaluation has been completed. CW-EMD has confirmed that the discontinuous (non-tangential) axisymmetric feature between the cast bowl region and machined suction nozzle OD is limited (domestically) to the 8 AP1000 RCP casings delivered to V.C. Summer units 2 & 3. 2. AP1000 RCP casing stress and fatigue supplemental analyses have been performed to assess the excess material condition discovered on the suction nozzle OD. The deviation has been determined to still satisfactorily meet the pressure boundary stress requirements of the ASME Code and can therefore be accepted as-is. 3. The analysis included generation of a 2D axisymmetric FEA [Finite Element Analysis] of the casing with a bounding representation of the as-built geometry, based on extraction of cross-sectional profiles from the V.C. Summer laser scan data of 2 casings. The 2D FEA was used to determine the stress concentration factor(s) associated with the as-built deviated feature, enabling a fatigue strength reduction factor to be estimated and applied to the existing 3D FEA casing fatigue (nominal design) analysis. 4. The maximum fatigue usage at the location of the deviation on the casing suction nozzle was conservatively estimated to increase from 0.287 to 0.633. This condition still satisfies the 1.0 usage limit specified in the ASME Code. 5. Therefore, this deviation does not constitute a substantial safety hazard, and the condition has been determined to be not reportable under the provisions of Title 10 Code of Federal Regulations, Part 21. Notified the R2DO(Bartley) and Part 21 Group (via email). |
| Where | |
|---|---|
| Westinghouse Electric Corporation Cheswick, Pennsylvania (NRC Region 1) | |
| Organization: | Curtiss Wright Electro Mechanical C |
| Reporting | |
| 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
| Time - Person (Reporting Time:+32.93 h1.372 days <br />0.196 weeks <br />0.0451 months <br />) | |
| Opened: | Jay Gardiner 13:56 Jan 13, 2017 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Jun 29, 2017 |
| 52487 - NRC Website | |
Westinghouse Electric Corporation with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
WEEKMONTHYEARENS 524872017-01-12T05:00:00012 January 2017 05:00:00
[Table view]10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 Interim Report - Excess Material Condition on the Casing for the Ap1000 Reactor Coolant Pump ENS 493032013-08-23T04:00:00023 August 2013 04:00:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part-21 Notification - Ap-1000 Time Response for the Safety Analysis Cannot Be Directly Measured 2017-01-12T05:00:00 | |