ML13066A185
| ML13066A185 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/16/2009 |
| From: | Jeffrey Mitman NRC/NRR/DRA |
| To: | Ferrante F NRC/NRR/DRA |
| References | |
| FOIA/PA-2012-0325 | |
| Download: ML13066A185 (2) | |
Text
Mitman, Jeffrey From:
Mitman, Jeffrey Sent:
Wednesday, December 16, 2009 12:58 PM To:
Ferrante, Fernando
Subject:
RE: NRC-Duke Correspondence Fernando, thanks for the help.
Jeff From: Ferrante, Fernando Sent: Wednesday, December 16, 2009 10:17 AM To: Mitman, Jeffrey
Subject:
NRC-Duke Correspondence
- Jeff, This is what I found:
- July 9,2009 Letter that contains the correspondence reference list (in Sharepoint)
- May 20, 2009 (reference #1 on list in July 9, 2009 Letter)
- April 30, 2009 (reference #2 on list in July 9, 2009 Letter) (in Sharepoint)
- June 10, 2009 (reference #3 on list in July 9, 2009 Letter)
- August 15, 2008,(reference #4 on list in July 9, 2009 Letter) (in Sharepoint)
Most are in Sharepoint already, the other two I found in ADAMS and uploaded them to Sharepoint.
Thank you, Fernando Ferrante, Ph.D.
Office of Nuclear Reactor Regulation (NRR)
Division of Risk Assessment (DRA)
Operational Support and Maintenance Branch (APOB)
Mail Stop: 0-10C15 Phone: 301-415-8385 Fax: 301-415-3577 1
V53
I U I would like to invite Fernando to our meeting tomorrow. He has done a lot of the hard looking at the data and the failures in the data and will thus add significantly to our discussions.
Jeff When: Thursday, December 17, 2009 8:30 AM-9:30 AM (GMT-05:00) Eastern Time (US & Canada).
Where: 010E4 Note: The GMT offset above does not reflect daylight saving time adjustments.
I attended a meeting yesterday in Jack's office along with Dave Skeen, Allen Howe, Meena and George to discuss path forward with Duke on Oconee flooding. Bottom line is that Jack wants an Order to them sent by Jan. 31 which defines their committed dates to us so that the issue would be part of their design basis and will prevent issue resolution from extending well into the future.
To support this, DE will need DRA's assistance in completing the adequate protection documentation to support the Order. In discussions with DE folks after the above meeting, DE indicated a need to better understand probability and adequate protection. Dave has stated that the PMP event is a 10-5 event and that overtopping can't occur (Duke and DE views). DE then has raised the question as to whether overtopping should be considered probabilistically as an initiating event. They think Duke will try to make the case that Oconee dam failure is a 10-6 event and that part of that reason is because overtopping is not credible and therefore not part of the probabilistic consideration.
This topic is what I want to discuss. Specifically, the following starting points are what we need to understand to develop DRA input further on adequate protection. (Remember from Geary Mizuno that an adequate protection issue needs to include a significant risk and NRR agrees that a 10-4 event with a CDF of 1 is an adequate protection issue so the agency needs to either (1) clearly demonstrate that we are at 10-4 or (2) demonstrate that even is overtopping (or other initiating events) is not credible that the resulting probability of flooding is still of significant enough risk to put it in adequate protection space.)
- 1. Verify (with Ken See or the RG 1.59 workshop notes) the frequency of PMP events--can this be narrowed to the SE US?
- 2. Deterministically PMPs need to be considered per our regs. So even if a PMP event is a 10-6 event, a licensee still needs to consider it. True or false?
- 3. How does any dependency between a PMP event and overtopping come into play in determining probability of overtopping?
- 4. How can overtopping be eliminated from consideration as a source of dam failure? Does the probability of PMP plus the probability of overtopping matter here (see question 3)?
- 5. Does the fact that a PMP event gets to within 1-2 feet of the top of the dam come into play in our view that deterministically we can't say overtopping is incredible? That is, how does uncertainty in the calculations come into play? Or said yet another way, if the licensee's and Rex's PMP calculations showed the reservoir level raising only to say 1115', would we be able to agree that overtopping is not credible?
- 6. If overtopping is not credible for Jocassee, how does that affect the initiating event frequency? Would we still be in adequate protection space? (See parenthetical before list above.)
Etc. What other issues do you all think need to be discussed?
DE is anxious to get this issue addressed and move forward and we will do our part to support them. I request that you not engage DE folks individually on these issues but assure them that we will get back to them after we have considered the probabilistic aspects involved. Knowing that there is a Jan. deadline (ambitious but trying to be reached none the same), we will need to move expeditiously. As such, I am also trying to schedule a meeting with Mark for the afternoon of this day.
2