ML022950019
| ML022950019 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 10/22/2002 |
| From: | Ellen Brown NRC/NRR/DLPM/LPD2 |
| To: | |
| Brown E, NRR/DLPM, 415-2315 | |
| References | |
| TAC MB5551 | |
| Download: ML022950019 (5) | |
Text
October 22, 2002 LICENSEE:
Florida Power & Light Company FACILITY:
Turkey Point Nuclear Plant, Unit 4
SUBJECT:
SUMMARY
OF CONFERENCE CALL WITH FLORIDA POWER & LIGHT COMPANY REGARDING RISK INFORMED RELIEF REQUEST FOR UNIT 4 (TAC NO. MB5551)
On September 24, 2002, the Nuclear Regulatory Commission (NRC) staff participated in a conference call with Florida Power and Light Company (FPL) to discuss staff observations resulting from the ongoing NRC review of the licensees submittal dated July 8, 2002. The July 8 submittal was a risk informed (RI) request for relief from the inservice inspection (ISI) requirements specified in the American Society of Mechanical Engineers Code. The topics for discussion were 1) noted changes in the probabilistic risk analysis (PRA) estimates from previous submittals; 2) quality of industry peer review of the PRA; 3) the differences between the magnitude of the "Piping Risk Contributions by System" between the Unit 3 and Unit 4 submittals, as shown on Table 3.10-1 of each of the submittals. The participants on the call were Stavroula Mihalakea, Ching Guey, and Mark Averett with FPL and Eva Brown, Stephen Dinsmore, Sarah Malik, and Robert Palla with the NRC.
The participants discussed the relatively large changes in PRA estimates observed between the Unit 3 and Unit 4 RI-ISI submittals. The differences were observed both in the estimates used to directly support the RI-ISI submittal and in the baseline core damage frequency (CDF) and large early release frequency (LERF) estimates. Units 3 and 4 are similar in design and construction. FPL stated that the reasons for the changes in the PRA estimates between Unit 3 and Unit 4 submittals were due to the Unit 3 ISI analysis being performed almost 2 years before that of Unit 4 and that a number of revisions to the PRA had occurred during the 2 years. FPL indicated that revisions are often made to the PRA and that the revisions are subject to quality control requirements contained in reliability and risk assessment group instructions.
The participants discussed the pressurized water reactors owners group peer review of the model as it pertained to an updated Unit 4 model. The review was performed in January 2002, on a model that had been modified twice since the 2000 model that was used to support the Unit 4 submittal. The licensee noted that the official draft report from the peer review team had only recently been issued but that the major findings of the review were communicated to FPL during the review. FPL stated that the potential impact of these findings on the results used to support the Unit 4 RI-ISI submittal had been reviewed and found to not significantly alter the results.
Several specific differences between a PRA version used to support the Unit 3 submittal, the version used to support the Unit 4 submittal, and the version reviewed in the peer review were briefly discussed. The licensee indicated that changes of the model used in the Unit 4 submittal included changes to the loss of coolant accident frequencies, reduction in the probability of direct containment heating given a high pressure core melt, crediting the use of the Unit 3 reactor water storage tank to supply water for high pressure injection, and other modeling enhancements. The licensee indicated that the Unit 4 submittal used an assumption of failing all injection lines while the Unit 3 submittal only failed one injection line. This change was implemented to reflect the lessons learned from the Unit 3 RI-ISI request for additional information response. Therefore, the CDF and LERF became smaller based on these revisions.
The NRC staff indicated their intention to determine what level of additional review of the Unit 4 PRA model was necessary to address concerns associated with the relatively large changes in the PRA results over time. The possibility of a site audit allowing access to the site documentation and licensee engineers to assist in locating specific models and to provide explanations for the models and methods was discussed.
FPL indicated their intention to provide clarifications in writing to any additional formal information requests received from the NRC regarding the information discussed during this call.
Sincerely,
/RA/
Eva A. Brown, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-250 and 50-251 cc w/encls: See next page
- S e e p r e v i o u s concurrence OFFICE PDII-2\\PM PDII-2\\LA SPSB\\SC
- PDII-2\\SC NAME EBrown BClayton MRubin AHowe DATE 10/21/2002 10/21/2002 10/3/2002 10/21/2002
Florida Power & Light Company TURKEY POINT PLANT cc:
Mr. J. A. Stall Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420 M. S. Ross, Attorney Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. John P. McElwain, Site Vice President Turkey Point Nuclear Plant Florida Power and Light Company 9760 SW. 344th Street Florida City, FL 33035 County Manager Miami-Dade County 111 NW 1 Street, 29th Floor Miami, Florida 33128 Senior Resident Inspector Turkey Point Nuclear Plant U.S. Nuclear Regulatory Commission 9762 SW. 344th Street Florida City, Florida 33035 Mr. William A. Passetti, Chief Department of Health Bureau of Radiation Control 2020 Capital Circle, SE, Bin #C21 Tallahassee, Florida 32399-1741 Mr. Craig Fugate, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 T. O. Jones, Plant General Manager Turkey Point Nuclear Plant Florida Power and Light Company 9760 SW. 344th Street Florida City, FL 33035 Walter Parker Licensing Manager Turkey Point Nuclear Plant 9760 SW 344th Street Florida City, FL 33035 Mr. Don Mothena Manager, Nuclear Plant Support Services P.O. Box 14000 Juno Beach, FL 33408-0420 Mr. Rajiv S. Kundalkar Vice President - Nuclear Engineering Florida Power & Light Company P.O. Box 14000 Juno Beach, FL 33408-0420
PD II-2 DOCUMENT COVER PAGE DOCUMENT NAME: C:\\ORPCheckout\\FileNET\\ML022950019.wpd
SUBJECT:
Conference Call Summary Regarding Turkey Point Unit 4 RI-ISI ORIGINATOR:
E. Brown SECRETARY: Marilyn Wohl DATE:
October 22, 2002
ROUTING LIST
NAME DATE
- 1. E. Brown 10/ /02
- 2. B. Clayton 10/ /02
- 3. M. Rubin 10/ /02
- 4. A. Howe 10/ /02
Accession Number __________
NRR Template Number NRR-064 (Mtg. Not.) _____
NRR-088 (RAI) _____
NRR-028 (Relief) _____
NRR-106 (Letters, Memo, Sholly) ___X__
NRR- (Other) _____
Enter dates, concurrences, etc. (Secy) _______
QC Electronic copy against hard copy (LA) _______
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