ML17313A110
| ML17313A110 | |
| Person / Time | |
|---|---|
| Issue date: | 11/09/2017 |
| From: | Mauricio Gutierrez Office of Nuclear Regulatory Research |
| To: | Fregonese V Nuclear Energy Institute |
| Mauricio Gutierrez, 301-415-1925 | |
| References | |
| NEI 16-16 | |
| Download: ML17313A110 (1) | |
Text
From: Gutierrez, Mauricio To: FREGONESE, Victor (vxf@nei.org)
Cc: Holonich, Joseph
Subject:
CCF Definition and Notes in NEI 16-16 [Draft 2]
Date: Thursday, November 09, 2017 10:27:00 AM
- Vic, We have reviewed the Common Cause Failure definition and notes you provided for inclusion in NEI 16-16.
The definition and notes proposed for future drafts of NEI 16-16 are:
CCF: Loss of function to multiple structures, systems or components due to a shared root cause (IEEE Std. 603-2009).
For this guideline, the following notes apply: 1) Loss of function means a malfunction of multiple SSCs caused by a specific I&C failure source. 2) Shared root cause is limited to I&C failure sources, including single random hardware component failure, an environmental disturbance, a software design defect, and a human error.
The clarifications provided during the November 02, 2017 public meeting were helpful in addressing our concerns. NRC agrees with maintaining the definition selected from IEEE Std. 603-2009 and clarifying the scope of loss of function and shared root causes with respect to scope of this guidance, with the following adjustments:
- Replace For this guideline, the following notes apply with The scope and use of this guideline is limited by the following notes:
- Place these notes in the body of NEI 16-16, such as Section 1.2 or 3.1, instead of in the Definitions (Section 2).
- Change note 1 to: Loss of function means undesirable behaviors (e.g., spurious actuations, failure to perform on demand, failure to maintain normal operating conditions, etc.) of multiple SSCs caused by an I&C failure source considered in this guideline.
This e-mail will be placed in ADAMS and placed in the package for the November 2 meeting.
Mauricio R. Gutierrez Instrumentations, Controls, and Electrical Engineering Branch Office of Nuclear Regulatory Research, TWFN 10B03 Phone: 301-415-1925 email: Mauricio.Gutierrez@nrc.gov