ML042930923
| ML042930923 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Peach Bottom, Oyster Creek, Byron, Braidwood, Limerick, Clinton, Quad Cities, LaSalle, Crane |
| Issue date: | 10/08/2004 |
| From: | Ader C NRC/RES/DRAA |
| To: | Gallagher M Exelon Generation Co |
| References | |
| Download: ML042930923 (4) | |
Text
October 8, 2004 Mr. Michael P. Gallagher Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348
Dear Mr. Gallagher:
In your April 7, 2004 letter, you requested that the NRC provide you a copy of the latest Standardized Plant Analysis Risk (SPAR) model and associated software for each of the Exelon/AmerGen plant sites. You stated that the purpose of your request was to allow a comparison between the SPAR models and the existing Exelon/AmerGen plant-specific, probabilistic risk assessment (PRA) models.
In response to your request, enclosed are ten (10) compact disks (CDs). Each CD contains the software for the current Revision 3 SPAR model for each of the Exelon/AmerGen plants, along with Version 6.80 of the SAPHIRE suite of probabilistic risk assessment (PRA) computer codes.
The SAPHIRE code suite is required to perform analyses with the SPAR models. Also enclosed for your use is a hard copy of the users manual for each of the SPAR models. All of the software packages are in the form of executable files that can be run directly from the CD.
These items are for your organizations use only and are not to be distributed further without the consent of the NRC. Also, please note that the information contained in each SPAR model is considered sensitive, and should be treated accordingly.
As requested, we are providing the most recent versions of the Revision 3 SPAR models for the following AmerGen plants: (1) Braidwood Station, Units 1 and 2; (2) Byron Station, Units 1 and 2; (3) Clinton Power Station, Unit 1; (4) Dresden Nuclear Power Station, Units 2 and 3; (5)
LaSalle County Station, Units 1 and 2; (6) Limerick Generating Station, Units 1 and 2; (7) Peach Bottom Atomic Power Station, Units 2 and 3; (8) Quad Cities Nuclear Power Station, Units 1 and 2; (9) Oyster Creek Generating Station; and (10) Three Mile Island Station, Unit 1.
We recently began an effort to develop enhanced Revision 3 SPAR models from the current Revision 3 models. The first step in this effort consists of incorporating an improved, updated loss-of-offsite power (LOOP) analysis module into the models. This improved LOOP module includes updated offsite and emergency a.c. power recovery data and the most recent reactor coolant pump (RCP) seal loss-of-coolant accident (LOCA) models available from the pressurized water reactor (PWR) owners groups. Completion of this first stage in the Revision 3 SPAR model enhancement process is scheduled for later this year. As soon as the upgraded Revision 3 SPAR models for the Exelon/AmerGen plants and their associated documentation have been completed, we will transmit them to you along with the software required to perform analyses with these upgraded models.
M. P. Gallagher 2
The Revision 3 SPAR model for each Exelon/AmerGen plant has been reviewed with the plants PRA staff and benchmarked against the PRA model for that plant. In addition, the SPAR models for the Braidwood and Limerick plants were subjected to more in-depth reviews against the respective plant PRAs during the comparison exercise conducted with the pilot program plants in the Mitigating Systems Performance Index (MSPI) Development Program.
Based on the results of the onsite quality assurance (QA) reviews, the results of the MSPI comparison exercise, and feedback received from NRC staff analysts using the models, we have identified a number of modeling and methodology issues that contribute in varying degrees to the differences observed between the SPAR models and the plant PRAs. As part of our Revision 3 SPAR model enhancement effort, we have evaluated the specific impact of each of the applicable issues on the baseline overall core damage frequency (CDF). From the results of this work, we then prepared for each SPAR model a table identifying the specific issue, any appropriate plant-specific comments, and a quantitative assessment of the impact of each issue on the estimated overall baseline CDF. Since we believe that the information regarding model limitations provided in the issue summary tables will be of benefit to your PRA staff analysts when they perform analyses with the SPAR models, they have been incorporated as a separate section in the front of the SPAR model users manual.
Although the Revision 3 SPAR models have been certified as acceptable for unrestricted use, we advise analysts to understand the inputs and assumptions inherent in the models and to apply model results giving them due consideration. The modeling and methodology issue summary table in the users manual should prove helpful in this regard. The Revision 3 SPAR models have been designed to capture the significant risk contributors associated with internal event initiators for plants operating at full power. Therefore, these models may not provide the level of detail necessary to capture the risk from the less significant contributors. Thus, for a particular application, the analyst may obtain results that do not appear to be reasonable.
Questions about the models should be addressed to Mr. Robert Buell of the Idaho National Engineering and Environmental Laboratory (INEEL) at (208) 536-9400 (e-mail address:
buelrf@inel.gov). Questions about the SAPHIRE code suite should be addressed to Mr. Ted Wood, INEEL, at (208) 526-8729 (e-mail address: stw@inel.gov). Questions and suggestions may also be directed to either of these gentlemen or to Dr. Patrick OReilly, NRC project manager for SPAR model development at (301) 415-7570 (e-mail address:
pdo@nrc.gov).
M. P. Gallagher 3
If you are interested in receiving on-going technical support for SAPHIRE, you are invited to join the SAPHIRE Users Group. Mr. John Schroeder, INEEL, at (208) 526-8755 (e-mail address:
roe@inel.gov) can provide more details about the group and the services offered.
Due to the potential sensitivity of the information contained in the Enclosures, they are not publicly available.
Sincerely,
/RA/
Charles E. Ader, Director Division of Risk Analysis and Applications Office of Nuclear Regulatory Research
Enclosures:
As stated cc: J. Craig/C. Paperiello, RES J. Dyer, NRR S. Black, NRR M. Tschiltz, NRR D. Pickett, NRR W. Lanning, RGN-I C. Pedersen, RGN-III
M. P. Gallagher 3
If you are interested in receiving on-going technical support for SAPHIRE, you are invited to join the SAPHIRE Users Group. Mr. John Schroeder, INEEL, at (208) 526-8755 (e-mail address:
roe@inel.gov) can provide more details about the group and the services offered.
Due to the potential sensitivity of the information contained in the Enclosures, they are not publicly available.
Sincerely,
/RA/
Charles E. Ader, Director Division of Risk Analysis and Applications Office of Nuclear Regulatory Research
Enclosures:
As stated cc:
J. Craig/C. Paperiello, RES J. Dyer, NRR S. Black, NRR M. Tschiltz, NRR D. Pickett, NRR W. Lanning, RGN-I C. Pedersen, RGN-III Distribution:
OERAB RF DRAA RF File Center DOCUMENT NAME: A:\\RESPTO EXLNLTR1R10.WPD To receive a copy of this document, indicate in the box: C = Copy wo/encl E = Copy w/encl N = No copy OFFICE
- OERAB E
- OERAB E
- OERAB N
- DRAA E
NAME POReilly MCheok PBaranowsky CAder DATE 10/4/04 10/5/04 10/8/04 10/8/04 OFFICIAL RECORD COPY OAR in ADAMS? (Y or N)
Y Publicly Available? (Y or N)
Y Template Number: RES-006 Accession Number: ML042930923 RES File Code: 2C-3