ML18155A004
| ML18155A004 | |
| Person / Time | |
|---|---|
| Site: | 99902028 |
| Issue date: | 07/09/2018 |
| From: | Joseph Holonich NRC/NRR/DLP/PLPB |
| To: | Dennis Morey NRC/NRR/DLP/PLPB |
| holonich J | |
| References | |
| Download: ML18155A004 (4) | |
Text
July 9, 2018 MEMORANDUM TO: Dennis C. Morey, Chief Licensing Processes Branch Division of Licensing Projects Office of Nuclear Reactor Regulation FROM: Joseph J. Holonich, Senior Project Manager /RA/
Licensing Processes Branch Division of Licensing Projects Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF MAY 24, 2018, MEETING TO DISCUSS DIGITAL INSTRUMENTATION AND CONTROL COMMON CAUSE FAILURE On May 24, 2018, U.S. Nuclear Regulatory Commission (NRC) staff held a Category 2 meeting with representatives from the Nuclear Energy Institute (NEI). The purpose of the meeting was to discuss the path forward on protection against common cause failure (CCF) in digital instrumentation and control (DI&C) systems and components. CCF is covered in Modernization Plan (MP) #1, Protection against Common Cause Failure, of the NRC Integrated Action Plan (IAP) for DI&C. A copy of the IAP can be found in the Agencywide Documents Access and Management System (ADAMS) package Accession No. ML17102B296. All other information related to the meeting and discussed in this summary can be found in the ADAMS package Accession No. ML18122A134.
In its presentation, the NRC staff provided background of the MP #1 activities and discussed the technical issues that were identified from other NRC staff and NEI interactions. A background on the NRC staff position and guidance to address CCF was also provided. In addition, the NRC staff summarized its activities and understanding of the status on NEI 16-16, Guidance for Addressing Digital Common Cause Failure.
There was a short discussion on the path forward for NEI 16-16. During that discussion, NEI stated that work on developing and reviewing NEI 16-16 had begun before the NRC staff prepared a draft of Regulatory Issue Summary (RIS) 2017-XX, Clarification of the NRC Staff Endorsement on the Use of EPRI [Electric Power Research Institute]I/NEI Joint Task Force Report, Guideline On Licensing Digital Upgrades: EPRI TR-102348, Revision 1, NEI 01-01: A Revision of EPRI TR-102348 to Reflect Changes to the 10 CFR [Code of Federal Regulations]
50.59 Rule (Report Previously Endorsed In RIS 2002-22). NEI also reported that once the CONTACT: Joseph J. Holonich, NRR/DLP/PLPB 301-415-7297
D. Morey NRC staff had started RIS 2012-22, Supplement 1, work on NEI 16-16 was stopped to allow resources to be focused on the RIS because the guidance in the RIS was needed by industry.
NEI informed the NRC staff that Appendix A of EPRI Technical Report 3002005326, Methods for Assuring Safety and Dependability when Applying Digital Instrumentation and Control Systems, which NEI 16-16 uses, is likely to undergo a significant revision this year. NEI 16-16 is modeled after EPRI 3002005326 and thus industry believes it would be prudent to wait until the EPRI document is revised (or a draft of the revision) before work on NEI 16-16 resumes.
Also, NEI stated that to husband resources industry focused on the NEI 96-07 Appendix D, Supplemental Guidance for Application of 10 CFR 50.59 to Digital Modifications, development as well as the Interim Staff Guidance (ISG) Digital I&C-ISG-06, Task Working Group #6:
Licensing Process. The industry view was that focusing these resources on the RIS, NEI 96-07, Appendix D, and Digital I&C ISG 06 was beneficial because progress was being made. NEI said that the industry expected to resume working on NEI 16-16 in the near future.
It was agreed that NEI would provide the staff with a proposed date for a meeting on restarting the NEI 16-16 effort. This was an action from the meeting.
Following the NEI 16-16 discussion, the NRC staff presented information on implementing the Commission Policy on protection against CCF in DI&C systems. Questions were raised regarding why the NRC staff was not pursuing elimination or a re-write of the policy in the Staff Requirements Memorandum on SECY-93-087, Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor (ALWR) Designs, with Comments, and also why the NRC staff was not looking to develop a Regulatory Guide in this area. The NRC staff explained that the policy does not impact the current efforts related to CCF in DI&C and that the policy would receive consideration in the context of the overall regulatory framework under IAP, MP #4b. Industry was satisfied with the NRC staff explanation.
In its presentation, the NRC staff noted that a Diversity and Defense-in-Depth (D3) analysis for the reactor trip system and engineered safety feature actuation system (ESFAS) to address CCF concerns continues to be required. Elaborating, the NRC staff explained the analysis can be either a best estimate (i.e., using realistic assumptions) or a design-basis analysis. The NRC staff stated that it planned to clarify the use of a graded approach for a D3 analysis for lower safety-significant systems. Industry agreed on the need to clarify D3 needs and requirements in NRC staff guidance.
The next steps were then discussed by the NRC staff. The focus was on providing an information paper regarding treatment of a potential DI&C CCF to the Commission in August 2018. NEI asked if review and comment by stakeholders would be part of the process on the document. The NRC staff stated that the information paper would not be made public until it was provided to the Commission. Further, the NRC staff explained that the Commission could vote to not release the paper. The NRC staff did explain that the content of the information paper would be similar to the information presented at this meeting regarding CCF.
Furthermore, the NRC staff noted that industry will get a chance to review or comment on the NRCs draft updates to guidance documents that will be revised following completion of the information paper.
NEI provided feedback regarding some of the CCF-related topics that should be addressed in the future, including the need to clarify scenarios that are considered beyond design-basis and within design-basis. The NRC staff responded that such issues will be addressed via the
D. Morey ongoing activities in support of the IAP, MP #4b, Assessment for Modernization of the Instrument & Control Regulatory Infrastructure, efforts.
Three stakeholders provided comments, with one stakeholder providing two comments. First, he stated that he believed there is a safety gap in the area of design attributes. The stakeholder stated that there is guidance on design attributes available to industry but that guidance has not been endorsed by the NRC staff. Therefore, he concluded, NEI 16-16 was needed now. In his second comment, the stakeholder stated that NEI 16-16 was not intended to apply to the ESFAS or the reactor protection system and that guidance was needed for those systems.
A second stakeholder stated that he is resubmitting his comments on BTP 7-19, Guidance for Evaluation of Diversity and Defense-In-Depth in Digital Computer-Based Instrumentation and Control Systems. He stated that the scope and applicability in this guidance changed but that the methodologies discussed in the document were not updated. Subsequent to the meeting, the stakeholder provided an email with comments on NRC guidance documents. This email along with the documents on which he commented can be found in the meeting package.
The third stakeholder supported the comments by the first two and emphasized the question of what is meant by design attributes.
The sole action from the meeting was for NEI to contact the staff with a proposed date for a meeting on NEI 16-16.
Docket No. 99902028
Package (ML18122A134)
Summary (ML18155A004)
- via e-mail NRC-001 OFFICE DLP/PLPB/PM RES/DE/ICEEB/BC* DE/EICB/ABC*
NAME JHolonich RJenkins DRahn DATE 06/11/2018 06/12/2018 06/11/2018 OFFICE DLP/PLPB/BC DLP/PLPB/PM NAME DMorey (SSanders for) JHolonich DATE 06/29/2018 07/09/2018