RS-03-195, Corrected Information Supporting a Technical Specification Change Request - Extension of Completion Time for Instrument Bus Inverters

Corrected Information Supporting a Technical Specification Change Request - Extension of Completion Time for Instrument Bus Inverters

ML032900989
Person / Time
Site:	Byron, Braidwood
Issue date:	10/14/2003
From:	Ainger K Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-03-195
Download: ML032900989 (4)

Text

Exe~n, 43 Inc 3a cc 1 e ft RS-03-1 95 October 14, 2003 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units I and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. SIN 50-454 and STN 50-455

Subject:

Corrected Information Supporting a Technical Specification Change Request Extension of Completion Time for Instrument Bus lnverters

Reference:

(1) Letter from Keith R. Jury (Exelon Generation Company, LLC) to U.S. NRC, Request for Technical Specification Change Extension of Completion Time for Instrument Bus Inverters, dated October 16, 2002 (2) Letter from Kenneth A. Ainger (Exelon Generation Company, LLC) to U.S. NRC, Response to a Request for Additional Information Regarding a Technical Specification Change Request Extension of Completion Time for Instrument Bus Inverters, dated June 20, 2003 In Reference 1, Exelon Generation Company, LLC (EGC) requested NRC approval of a proposed change to Technical Specifications (IS) of Facility Operating License Nos. NPF-72, NPF-77, NPF-37 and NPF-66, for the Braidwood Station, Units 1 and 2, and the Byron Station, Units 1 and 2, respectively. The proposed change would revise the Completion Time for Required Action A.1 of IS 3.8.7, Inverters Operating, from the current 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, for one instrument bus inverter inoperable, to 14 days.

During the NRCs review of the requested change, a number of questions were raised and the NRC subsequently requested that we provide additional information to support justification of the proposed IS change. Our response to the NRCs request was provided in Reference 2. In Attachment I of Reference 2, we presented data regarding the inverter core damage frequency (CDF) results and inverter large early release frequency (LERF) results. Specifically, Table 3, Inverter CDF Results, and Table 4, Inverter LERF

October 14, 2003 U. S. Nuclear Regulatory Commission Page 2 Results, found in Reference 2, Attachment 1, pages 8 and 9 respectively, present this data in tabular format. During routine ongoing probabilistic risk assessment (PRA) model reviews, minor discrepancies were identified that affect the CDF and LERF data related to the inverters, This issue was entered into the EGC corrective action program. The impact of these discrepancies on the CDF and LERF values given in Tables 3 and 4 is not significant and does not affect the conclusions of the original Technical Specification change request presented in Reference 1. The corrected data is being submitted to the NRC to ensure accuracy of the supporting data for the proposed change. The corrected data is provided in Attachment I to this letter.

Should you have any questions related to this matter, please contact J. A. Bauer at (630) 657-2801.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on e~A,~~o3 ________________________

Kenneth A. Ainger Manager, Licensing : Corrected Information Supporting a Technical Specification Change Request Extension of Completion Time for Instrument Bus Inverters

Attachment I Corrected Information Supporting a Technical Specification Change Request Extension of Completion Time for Instrument Bus Inverters The below information was originally submitted to the NRC in a letter from Kenneth A. Ainger (Exelon Generation Company, LLC) to U.S. NRC, Response to a Request for Additional Information Regarding a Technical Specification Change Request Extension of Completion Time for Instrument Bus Inverters, dated June 20, 2003.

Both the original data and corrected data (in bold) are given below. The original Table 3 is found on Attachment I, page 8, in the above noted June 20, 2003 letter.

TABLE 3 Inverter CDF Results UNIT INV 005 CDF* DELTA CDF icco~ DELTA AVE CYCLE CDF PER YEAR PER YEAR <5E-7 <1 E-6IYR BRAIDWD ui NONE 3.26E-05 NA NA 3.56E-09 111 3.26E-05 1.39E-1O 5.33E-12 112 3.26E-05 O.OOE+OO O.OOE+OO 113 3.26E-05 O.OOE+OO O.OOE÷OO 114 3.27E-05 1.39E-07 5.34E-09 BRAIDWD U2 NONE 3.24E-05 NA NA 357E-09 211 324E-05 1.39E-1O 5.33E-12 212 3.24E-05 O.OOE+OO O.OOE+OO 213 3.24E-05 O.OOE+OO O.OOE+OO 214 3.25E-05 1.40E-07 5.35E-09 3.26 E-05 BYRON Ui NONE 5.36E-05 NA NA 2.56E-09 2.8E-09 111 536E-05 1.19E-1O 4.56E-12 112 5.36E-05 O.OOE+OO O.OOE÷OO 113 5.36E-05 O.OOE÷OO O.OOE+OO 114 537E-05 1.09E-07 4.19E-09 BYRON U2 NONE 5.26E-05 NA NA 2.56E-09 5.27E-05 2.57E-09 211 5.26E-05 1.19E-1O 4.55E-12 5.27E-05 4.56E-12 212 526E-05 O.OOE+OO O.OOE+OO 5.27E-05 213 526E-05 O.OOE+OO O.OOE÷OO 5.27E-05 214 5.27E-05 1.OOE-07 384E-09 5.28E-05 3.85E-09

• CDF truncation at 1E-lO Page 1 of 2

Attachment I Corrected Information Supporting a Technical Specification Change Request Extension of Completion Time for Instrument Bus Inverters Both the original data and corrected data (in bold) are given below. The original Table 4 is found on Attachment 1, page 9, in the above noted June 20, 2003 letter.

TABLE 4 Inverter LERF Results UNIT INV OOS LERF* DELTA LERF ICLERP DELTA AVE CYCLE LERF Per year Per year <5E-8 <1 E-7/YR BRAIDWD Ui NONE 406E-06 NA NA 3.26E-1O 111 407E-06 4.08E-09 1.56E-iO 112 4.06E-06 O.OOE+OO O.OOE+OO 113 406E-06 O.OOE+OO O.OOE+OO 114 4.07E-06 8.66E-09 3.32E-1O 8.65E-09 BRAIDWD U2 NONE 4.31 E-06 NA NA 4.17E-1O 211 4.31E-06 4.08E-09 1.56E-1O 212 4.31 E-06 O.OOE+OO O.OOE+OO 213 4.31E-06 O.OOE+OO O.OOE+OO 214 4.32E-06 1.22E-08 4.69E-1O BYRON Ui NONE 4.85E-06 NA NA 2.08E-1O 4.84E-06 111 4.85E-06 2.24E-09 8.60E-1 1 4.84E-06 112 4.85E-06 O.OOE+OO O.OOE+OO 4.84E-06 113 4.85E-06 O.OOE+OO O.OOE+OO 4.84E-06 114 4.85E-06 5,91E-09 2.26E-1O 2.27E-10 BYRON U2 NONE 5.49E-06 NA NA 2.63E-1O 5.48E-06 211 5.49E-06 2.22E-09 8.52E-11 5.48E-06 212 5.49E-06 O.OOE+OO O.OOE+OO 5.48E-06 213 5.49E-06 O.OOE+OO O.OOE+OO 5.48E-06 214 5.50E-06 8.08E-09 3.1OE-1O 5.49E-06 8.04E-09 3.09E-l0

• LERF truncation at 1 E-1 1 Page 2of2