ML19269B699
| ML19269B699 | |
| Person / Time | |
|---|---|
| Issue date: | 09/03/2019 |
| From: | David Rahn NRC/NRR/DE/EICB |
| To: | Tekia Govan NRC/NRR/DIRS/IRGB |
| Govan T, 415-6197, NRR/DIRS | |
| References | |
| Download: ML19269B699 (4) | |
Text
From: Rahn, David To: Govan, Tekia Cc: Morton, Wendell; Alvarado, Rossnyev; Zhang, Deanna; Rebstock, Paul
Subject:
FW: Update to Summary of Key Comments from Anonymous Commenter Date: Tuesday, September 03, 2019 10:20:24 AM Attachments: Summary of Key Comments on the Proposed BTP 7-19 Rev 8-B.pdf Hi Tekia:
On Thursday of last week, the anonymous commenter sent a revised version of the summary of key comments that was attached to my email to you on August 29th. The revised version has 5 key comments instead of 4. Could you please substitute this version into the Meeting Summary attachments? (No change to the other attachment.)
- Thanks, Dave From: Rahn, David Sent: Thursday, August 29, 2019 8:47 AM To: Govan, Tekia <Tekia.Govan@nrc.gov>
Cc: Morton, Wendell <Wendell.Morton@nrc.gov>; Alvarado, Rossnyev
<Rossnyev.Alvarado@nrc.gov>; Zhang, Deanna <Deanna.Zhang@nrc.gov>; Rebstock, Paul
<Paul.Rebstock@nrc.gov>
Subject:
FW: Commented Line-by-line Mark-up of BTP 7-19 from an Anonymous Commenter Hi Tekia:
Late last night I received a package with two attachments:
- a. A Line-by-line mark-up of the staffs proposed Draft Rev. 8 to BTP 7-19, and
- b. A summary of the key comments within the mark-up.
The sender wishes to remain anonymous.
I will mention that we received comments on the Draft BTP revision from parties that are not affiliated with NEI, and that these comments will be included within the meeting summary.
Dave From: Rahn, David Sent: Wednesday, August 28, 2019 6:15 PM To: Govan, Tekia <Tekia.Govan@nrc.gov>
Cc: Morton, Wendell <Wendell.Morton@nrc.gov>
Subject:
RE: Commented Line-by-line Mark-up of BTP 7-19 from an Anonymous Commenter Thanks!
From: Govan, Tekia Sent: Wednesday, August 28, 2019 6:14 PM To: Rahn, David <David.Rahn@nrc.gov>
Cc: Morton, Wendell <Wendell.Morton@nrc.gov>
Subject:
RE: Commented Line-by-line Mark-up of BTP 7-19 from an Anonymous Commenter Dave:
If its mentioned (by you) during the meeting, I do not see why we wouldnt be able to add the anonymous comments to the meeting summary. However, it should be noted that the NRC staff is not required to post a response, and since the person wishes to remain anonymous, they offer no way to respond, even if the staff wish to do so. At will, the staff may review the comments and incorporate such comments as they deem appropriate.
If this person wishes to have their comments addressed, they should post the comments during the public comment period. The staff would be responsible to provide a public response at that time.
See you tomorrow.
Tekia Tekia Govan, Project Manager US Nuclear Regulatory Commission 301-415-6197 Tekia.Govan@nrc.gov From: Rahn, David Sent: Wednesday, August 28, 2019 5:49 PM To: Govan, Tekia <Tekia.Govan@nrc.gov>
Subject:
Commented Line-by-line Mark-up of BTP 7-19 from an Anonymous Commenter Hi Tekia:
I expect to receive a complete line-by-line commented mark-up of the August 19th version of the BTP from an industry representative who wishes to remain anonymous. I dont believe I will receive it in time to support tomorrows public meeting as a handout. Can we still include it as an attachment to the meeting summary if we mention at the meeting that besides NEIs comments (which we will be discussing in detail), we received comments from other stakeholders that will be attached to the meeting summary?
- Thanks, Dave David L. Rahn, P. E.
Senior Electronics Engineer, Instrumentation and Controls Branch Division of Engineering, Office of Nuclear Reactor Regulation
US Nuclear Regulatory Commission Mail Code O09H05 11555 Rockville Pike Rockville, MD 20852 (301) 415-1315
Comments on the NRC Staffs Proposed Draft 8 to SRP Section BTP 7-19 This is a summary of our key comments:
- 1. The distinction between a D3 assessment and Qualitative assessment is unclear and unnecessary. For A1, A2 and B1 systems a CCF vulnerability assessment is required, and a plant safety assessment is needed for any CCFs that are not prevented. The only difference is that the defensive measures that can be credited to reach a no CCF conclusion for a design defect in A1 systems are prescriptive - sufficient internal diversity or sufficient testability; the defensive measures that can be credited for A2 and B1 systems are not prescriptive and can be identified and defended by the licensee. Weve stated this in one sentence, the current draft requires more than 30 pages to say this.
- 2. The document defines best estimate as allowing relaxed initial conditions, but for previous digital systems best estimate has also meant relaxed acceptance criteria, and qualitative assessments by safety analysis experts vs. quantitative assessments using computer codes.
- 3. Nowhere in this document does it say that an AOO or PA with concurrent LOOP and concurrent digital CCF does not need to be considered. This has been accepted by the staff for all previous digital safety system reviews; it is essential to a manageable CCF strategy. There is no practical technical solution to managing this multiple CCF scenario (LOOP is a CCF).
- 4. The document casually mentions single failures that can lead to CCFs in integrated digital systems. But these CCFs should be emphasized, because they are much more troublesome than CCFs due to a design defect. Single failures are expected during the life of the plant; therefore, they are within the plants design basis. If there are inadequate defensive measures to prevent these CCFs, conservative quantitative plant safety analysis is required. Most important is that these CCFs can cause unbounded plant transients that must be identified in the FSAR as new AOOs.
- 5. SECY 93-087 requires consideration of CCF in any system that is credited for AOO or PA mitigation. This goes well beyond the protection system, which is limited to RPS and ESFAS.
Any system directly credited for AOO or PA mitigation is an A1 system. The prescriptive defensive measures, sufficient internal diversity or sufficient testability, are applicable to all systems directly credited for AOO or PA mitigation (i.e., all A1 systems).