05000483/FIN-2014004-02
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Finding | |
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Title | Failure to Verify Material Properties Prior to Installation |
Description | The inspectors reviewed a self-revealing finding involving failure to verify the proper material was installed in the plant during a modification to the circulating water pumps. Specifically, Request for Resolution 201300416 specified the use of ASTM A276 410 stainless steel cap screws with a tensile strength around 186 ksi. Contrary to this, 410 stainless steel cap screws with a tensile strength between 201 ksi and 221 ksi were installed. Because the tensile strength was much higher, and thus more brittle and susceptible to stress corrosion, these cap screws were not appropriate for the application. This led to failure of the cap screws and the separation of the shaft coupling for circulating water pump B after less than one operating cycle in service, degrading condenser vacuum. The licensee removed the modification and installed the original type cap screws. This issue was entered into the licensees corrective action program as Callaway Action Request 201404722. The inspectors determined that failure to verify the correct materials were installed in the plant during a modification was a performance deficiency. This performance deficiency is more than minor because it is associated with the equipment performance attribute of the Initiating Events Cornerstone and affects the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as during power operations. Specifically, failure to install the correct material resulted in failure of circulating water pump B and degrading condenser vacuum. The inspectors evaluated the finding using NRC Inspection Manual 0609, Appendix A, Exhibit 1, Initiating Event Screening Questions. The inspectors determined the finding was of very low safety significance (Green) because the transient initiator did not cause a reactor trip and the loss of mitigating equipment. This finding has an avoid complacency cross-cutting aspect within the human performance area because the licensee relied on the vendor to provide the correct material and did not verify the cap screws met the material specification. |
Site: | Callaway |
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Report | IR 05000483/2014004 Section 1R12 |
Date counted | Sep 30, 2014 (2014Q3) |
Type: | Finding: Green |
cornerstone | Initiating Events |
Identified by: | Self-revealing |
Inspection Procedure: | IP 71111.12 |
Inspectors (proximate) | C O'Keefe C Peabody D Proulx G Callaway G Guerra L Ricketson P Elkmann P Hernandez S Garchow T Hartman Z Hollcraft |
CCA | H.12, Avoid Complacency |
INPO aspect | QA.4 |
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Finding - Callaway - IR 05000483/2014004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Callaway) @ 2014Q3
Self-Identified List (Callaway)
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