ML18229A122

Summary of Meeting with Exelon Generation Company, LLC Regarding the Response to the 2nd Round of Request for Additional Information (RAI) Questions at Peach Bottom Atomic Power Station, Units 2 and 3 (Pbaps)

ML18229A122
Person / Time
Site:	Peach Bottom
Issue date:	09/17/2018
From:	Jennifer Tobin Plant Licensing Branch 1
To:	Bryan Hanson Exelon Nuclear
Tobin J
References
EPID L-2017-LLA-0821
Download: ML18229A122 (4)

Text

LICENSEE: EXELON GENERATION COMPANY, LLC FACILITY: PEACH BOTIOM ATOMIC POWER STATION, UNITS 2 AND 3

SUMMARY

OF AUGUST 16, 2018, MEETING WITH EXELON GENERATION COMPANY, LLC REGARDING THE RESPONSE TO THE REQUEST FOR ADDITIONAL INFORMATION AT PEACH BOTIOM ATOMIC POWER STATION, UNITS 2 AND 3 (EPID L-2017-LLA-0821)

On August 16, 2018, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC), representatives of Exelon Generation Company, LLC (Exelon, the licensee), and other interested parties from industry. The purpose of the meeting was to discuss the licensee's response to the second round of request for additional information (RAI)

RAI 08.d.01, concerning reactor core isolation cooling (RCIC) and high pressure coolant injection (HPCI) turbine failure probabilities. The meeting notice, dated August 3, 2018, is available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML18225A271. The RAls from NRC can be found in ADAMS at Accession No. ML18200A274. Exelon's response can be found in ADAMS at Accession No. ML18222A387. A list of participants in the phone call is enclosed.

The NRC staff provided a brief background discussion about the RCIC and HPCI turbine failure probabilities issue and discussed Exelon's RAI response regarding their assertion that the assigned point estimate HPCI/RCIC turbine failure probability of 0.05 was not a key assumption in the probabilistic risk assessment (PRA) model. Their justification was that when performing a sensitivity study assuming a factor of 10 multiplier on the turbine failure problem as the NRC requested, approximately 50 structures, systems, and components (SSCs) would move into high safety significance (HSS) and 72 SSCs would move from HSS to low safety significance.

However, the 50 SSCs that are identified as HSS were already identified through other parts of the categorization process. The NRC pointed out that Exelon's sensitivity study showed the importance of the assumption regardless of whether these newly identified SSCs were already identified through other means as HSS as this could change in future PRA model updates.

Therefore, the results of this sensitivity study should be provided to the Integrated Decision-Making Panel as part of the categorization process according to the NRG-endorsed NEI guidance.

The licensee agreed but noted that the industry is now performing additional testing on the ability of the turbines to operate in heavy steam environments, and using the future data to evaluate turbine failure probability the ability of the turbines may be preferable to a factor of 10 sensitivity study. NRC staff agreed that future model updates could change this sensitivity factor (given supporting data) without the need to seek approval from NRC. Exelon agreed to submit a supplement regarding this issue in the near future.

Several members of the public participated in listening mode but did not provide comments. No public meeting feedback forms were not received.

Please direct any inquiries to me at 301-415-2328, or Jennifer.Tobin@nrc.gov.

Jeq~~i~

Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-277 and 50-278

Enclosure:

List of Attendees cc: Listserv

SUMMARY

OF AUGUST 16, 2018, MEETING WITH EXELON GENERATION COMPANY, LLC REGARDING THE RESPONSE TO THE SECOND ROUND OF REQUEST FOR ADDITIONAL INFORMATION AT PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 (EPID L-2017-LLA-0821) DATED SEPTEMBER 17, 2018 DISTRIBUTION:

PUBLIC RidsACRS_MailCTR Resource RidsNrrDorlLp11 Resource RidsNrrLASRohrer Resource RidsNrrPMPeachBottom Resource RidsRgn1 MailCenter Resource RidsNrrDraApla Resource JBowen, OEDO MLevine, NRR ADAM s Accession No. M eetmg Nof ice ML18225A271 M ee f mg S ummary ML18229A122 OFFICE NRR/DORL/LPL 1/PM NRR/DORL/LPL 1/LA NRR/DORL/LPL 1/BC NRR/DORL/LPL 1/PM NAME JTobin SRohrer JDanna JTobin DATE 8/21/18 8/20/18 9/14/18 9/17/18 OFFICIAL RECORD COPY