ML17346B281
| ML17346B281 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 12/13/2017 |
| From: | Archambo N, Fregonese V Duke Energy Corp, Nuclear Energy Institute |
| To: | Office of Nuclear Reactor Regulation |
| Holonich J | |
| References | |
| Download: ML17346B281 (12) | |
Text
MEETINGBETWEENTHEU.S.NUCLEAR REGULATORYCOMMISSIONSTAFFAND THENUCLEARENERGYINSTITUTETOPREVIEW NEI1616,GUIDANCEFORADDRESSING DIGITALCOMMONCAUSEFAILURE Vic Fregonese Nuclear Energy Institute Neil Archambo Duke Energy December 13, 2017
- Discussion of Sufficiently Low
- Use of Best Estimate Safety Analysis Techniques In NEI 16-16
- Common Cause Failure Definition
- NEI 96-07 Appendix D, Section 4.3.6
- Relationship Between NEI 16-16 and Appendix D
- NEI 16-16 Staff Comments
- Path Forward
- Summary/Wrap Up Topics for Discussion 2
Software CCF Likelihood 3
NEI 16-16, Draft 2, proposes the use of best estimate safety analysis methods to address CCF not sufficiently low outcomes (white space area) when addressing 50.59 Evaluation Questions 5 and 6 Based on discussions with industry licensing SMEs, it has been determined that best estimate methods cannot be used to address 50.59 questions NEI 16-16 Revision 3 will eliminate guidance for using best estimate safety analysis techniques for addressing 50.59 questions NEI 16-16 will continue to provide technical guidance on use of best estimate safety analysis techniques as appropriate (i.e.,
when licensee pursues a LAR)
Use of Best Estimate Techniques In NEI 16-16 4
NEI Proposed Definition of 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 failure 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.
NRC Staff Proposal for Note 1:
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.
Common Cause Failure Definition 5
- Appendix D, Section 4.3.6, provides guidance on addressing 10 CFR 50.59 Criterion 6 - the possible creation of a malfunction with a different result
- Section 4.3.6 discussions center on what malfunction results are to be evaluated - safety analysis results
- The Appendix D team (MP2) has lead for industry
- NEI 16-16 will be revised to remove any implied 50.59 guidance
- Note that Revision 3 of NEI 16-16 will use terminology consistent with Appendix D, as needed NEI 96-07 Appendix D, Section 4.3.6 6
Recall that one of the goals of the DI&C initiative is the separation of NEI 01-01 technical and licensing guidance Although NEI 16-16 (as currently drafted) calls out a relationship to licensing (50.59 and LARs), this is unnecessary NEI 16-16 provides technical guidance for determination of CCF susceptibility Appendix D provides licensing guidance specific to digital changes A 50.59 practitioner may exploit a number of different technical products to support arguments and conclusions, such as:
o Seismic Calculations o
Heat Load Calculations o
Power System Analysis Calculations o
Instrument Uncertainty/Setpoint Calculations o
PRA Outcomes o
Radiation Dose Calculations o
Failure Modes and Effects Analysis (FMEA)
Relationship Between Appendix D and NEI 16-16 7
None of the guidance associated with the above listed technical products make reference to their use in 50.59 A CCF susceptibility analysis is simply another technical product the 50.59 practitioner will use in supporting licensing arguments and conclusions Appendix D does not reference any specific technical guidance
- Appendix D simply states an engineering evaluation was performed Technical evaluations are developed to support the design - the 50.59 practitioner will use technical evaluation outcomes as needed to support the 50.59 conclusions NEI 16-16 should only determine if CCF is sufficiently low or not sufficiently low Relationship Between Appendix D and NEI 16-16 8
RIS 2017-XX provides a qualitative analysis framework that can be used to determine overall SSC reliability The RIS 2017-XX qualitative assessment can be used to address 50.59 Questions 1, 2, 5, & 6 NEI 16-16 provides design attributes for accessing CCF likelihood As currently drafted, NEI 16-16 provides useful technical basis for addressing 50.59 Questions 5 & 6, but is of no use for addressing 50.59 Questions 1 & 2 When Appendix D and NEI 16-16 are endorsed, RIS 2017-XX may be retired along with NEI 01-01 NEI 16-16 should incorporate the qualitative analysis elements in RIS 2017-XX to ensure NEI 16-16 provides suitable technical basis for addressing 50.59 Evaluation Questions 1, 2, 5, and 6 NEI 16-16 Guidance Versus RIS 2017-XX Guidance 9
Comments 1,13, 16, 17, 26, 39, 47, 48, and 49 are associated with use of BDBE and best estimate safety analysis methods -
NEI 16-16 will limit use of best estimate analysis for LAR submittals Comments 2,15, 18, 28, 38, and 40 are related to terminology -
NEI 16-16 will use terminology that is specifically technical or consistent with Appendix D, as appropriate Comments 8, 14, 15, 18 and 28 are associated with the relationship between Appendix D and NEI 16 slides 7 and 8 address this issue NEI has reviewed notes and actions from the last public meeting and provided a tabulation of the proposed resolution for the staff comments on the body of NEI 16-16 (provided in a separate document to support todays meeting)
Discussion on NEI 16-16 Staff Comments 10
Draft 3 of NEI 16-16 will:
o Incorporate staff comments and proposed resolutions discussed to date o
Eliminate use of best estimate safety analysis methods for addressing 50.59 questions (will retain for LAR submittals) o Include technical information to support answering 50.59 Questions 1 & 2 (incorporate relevant guidance from RIS 2017-XX) o Adopt Appendix D terminology as appropriate NEI will continue to update NRC staff on the comment status in subsequent public meetings Review of staff comments on NEI 16-16 Appendix A Next public meetings - February and March Path Forward 11
Meeting Summary
- Discussed software CCF sufficiently low
- Dispositioned the use of best estimate safety analysis methods to address 50.59 questions
- Discussed Common Cause Failure definition
- NEI 16-16 will adopt Appendix D terminology, as appropriate
- Discussed relationship between Appendix D and NEI 16-16
- Dispositioned a number of NEI 16-16 staff comments 12