RS-14-091, Updated Responses to NRC Requests for Additional Information, Set 3, Dated November 25, 2013, License Renewal Application

Updated Responses to NRC Requests for Additional Information, Set 3, Dated November 25, 2013, License Renewal Application

ML14080A187
Person / Time
Site:	Byron, Braidwood
Issue date:	03/21/2014
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Division of Operating Reactor Licensing
References
RS-14-091
Download: ML14080A187 (10)

Text

Michael P. Gallagher Vice President. License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way Kennett Square. PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-14-091 March 21, 2014 U. S. Nuclear Regulatory Commission Attention: 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 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

Updated Responses to NRC Requests for Additional Information, Set 3, dated November 25, 2013, related to the Braidwood Station, Units 1 and 2 and Byron Station, Units 1 and 2 License Renewal Application

References:

1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon) to NRC Document Control Desk, dated May 29, 2013, "Application for Renewed Operating Licenses."

2. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon) to NRC Document Control Desk, dated December 17, 2013, "Response to NRC Requests for Additional Information, Set 3, dated November 25, 2013, related to the Braidwood Station, Units 1 and 2 and Byron Station, Units 1 and 2 License Renewal Application In the Reference 1 letter, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2 (BBS). In Reference 2, Exelon provided responses to NRC Set 3 Requests for Additional Information.

After review of these responses, the NRC staff indicated that additional detail related to the responses to two of the Set 3 RAis, RAI 2.1.3.4-1 and RAI 2.1.3.4-3, is required. This letter provides updated responses to each of these two RAis. These updated responses replace the original responses in their entirety.

March 21, 2014 U.S. Nuclear Regulatory Commission Page 2 Responses to the other four RAis that were part of Set 3 are not affected by this update; therefore, they are not included in this package.

Enclosure A contains the updated responses to RAI 2.1.3.4-1 and RAI 2.1.3.4-3.

Enclosure B contains an update to LRA Section 2, consistent with the updated RAI responses.

There are no new or revised regulatory commitments contained in this letter.

If you have any questions, please contact Mr. AI Fulvia, Manager, Exelon License Renewal, at 610-765-5936.

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

Respectfully, Michael P. Gallagher <'

Vice President - License Renewal Projects Exelon Generation Company, LLC

Enclosures:

A: Updated Responses to Requests for Additional Information B: Updates to LRA Section 2 cc: Regional Administrator- NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Senior Resident Inspector, Braidwood Station NRC Senior Resident Inspector, Byron Station NRC Project Manager, NRR-DORL-Braidwood and Byron Stations Illinois Emergency Management Agency- Division of Nuclear Safety

RS-14-091 Enclosure A Page 1 of 5 Enclosure A Byron and Braidwood Stations (BBS), Units 1 and 2 License Renewal Application Updated Responses to Requests for Additional Information RAI 2.1.3.4-1 RAI 2.1.3.4-3 Note: To facilitate understanding, the original RAI responses are shown in normal font.

Changes resulting from this submittal are highlighted with bolded italics for inserted text.

RS-14-091 Enclosure A Page 2 of 5 RAI 2.1.3.4-1, SATs and SBO recovery boundary - Byron Applicability: Byron

Background:

On Page 8.3-5 of the Byron-Braidwood Stations (BBS) Updated Final Safety Analysis Report (UFSAR), Section 8.3.1.1.2.1, the licensee provided the preferred configuration for both stations Unit 1 and Unit 2 under normal operating conditions in the following statements: The 4160-volt ESF bus 141 (241 [for Unit 2]) fed from the 345-kV utility grid through system auxiliary transformer (SAT) 142-1 (242-1) and circuit breaker 1412 (2412) and The 4160-volt ESF bus 142 (242) fed from the 345-kV utility grid through SAT 142-2 (242-2) and circuit breaker 1422 (2422)... The staff notes that these statements indicate that there are SATs and circuit breakers between the 345-kilo-volts (kV) utility grid and the 4160-volt ESF buses.

Issue:

Figure 2.1-2 in the LRA, Section 2.1.3.4, which depicts the Byron Station Blackout (SBO) recovery boundary, does not show circuit breakers 1412, 1422, 2412, and 2422 between the 345-kV circuit breakers and the 4160-volt ESF buses.

Request:

a. Clarify why circuit breakers 1412, 1422, 2412 and 2422 are not included in Figure 2.1-2.

b. Confirm that all components, including breakers and disconnect switches, between the 345-kV utility grid and the 4160-volt ESF buses that are in the SBO recovery path are within the scope of license renewal.

c. Provide a revised Figure 2.1-2, as applicable, for the Byron SBO recovery boundary including all components in the SBO recovery path that shows a clear distinction between components that are within the scope of license renewal and those that are not.

Exelon Response:

a. LRA Figure 2.1-2, Byron Station Blackout (SBO) Recovery Boundary is a simplified representation of the Byron SBO recovery path. Circuit breakers 1412, 1422, 2412, and 2422 were not shown on LRA Figure 2.1-2 and circuit breakers 1413, 1414, 1423, 1424, 2413, 2414, 2423, and 2424 were shown, but not labeled on LRA Figure 2.1-2 to maintain the figure as simple as possible. Circuit breakers 1412, 1413, 1414, 1422, 1423, 1424, 2412, 2413, 2414, 2422, 2423, and 2424 are within the scope of license renewal.

b. The components in the SBO recovery path between the 345-kV utility grid and the 4160-volt ESF buses, including breakers and disconnect switches, are within the scope of license renewal.

RS-14-091 Enclosure A Page 3 of 5 The 4160-volt ESF bus power paths from:

the normal offsite source from the 345-kV utility grid, the reserve offsite source from the 345-kV utility grid, the alternate AC source are described below using Byron Unit 1, 4160-volt ESF bus 141 as an example.

The normal offsite source from the 345-kV system is through the Unit 1 System Auxiliary Transformer 142-1 and then through breaker 1412 to energize the 4160-volt ESF bus 141.

The reserve offsite source from the 345-kV system is through the Unit 2 System Auxiliary Transformer 242-1 and then through breakers 2412, 2414 and 1414 to energize the 4160-volt ESF bus 141.

The alternate AC source is from the Unit 2 diesel generator DG2A through breakers 2413, 2414 and 1414 to energize the 4160-volt ESF bus 141.

The power paths for remaining Byron Units 1 and 2 4160-volt ESF buses are similar.

c. Consistent with this response, LRA Figure 2.1-2, page 2.1-14, is revised as shown in Enclosure B. The revised LRA Figure 2.1-2 for the Byron SBO recovery boundary includes circuit breakers 1412, 1422, 2412, and 2422 and labels for circuit breakers 1413, 1414, 1423, 1424, 2413, 2414, 2423, and 2424. Also, an explicit demarcation line that shows a clear distinction between components that are within the scope of license renewal and those components that are not in the scope of license renewal is added to LRA Figure 2.1-2.

RS-14-091 Enclosure A Page 4 of 5 RAI 2.1.3.4-3, SATs and SBO recovery boundary - Braidwood Applicability: Braidwood

Background:

On Page 8.3-5 of the Byron-Braidwood Stations (BBS) Updated Final Safety Analysis Report (UFSAR), Section 8.3.1.1.2.1, the licensee provided the preferred configuration for both stations Unit 1 and Unit 2 under normal operating conditions in the following statements: The 4160-volt ESF bus 141 (241 [for Unit 2]) fed from the 345-kV utility grid through system auxiliary transformer (SAT) 142-1 (242-1) and circuit breaker 1412 (2412) and The 4160-volt ESF bus 142 (242) fed from the 345-kV utility grid through SAT 142-2 (242-2) and circuit breaker 1422 (2422)... The staff notes that these statements indicate that there are SATs and circuit breakers between the 345-kilo-volts (kV) utility grid and the 4160-volt ESF buses.

Issue:

Figure 2.1-3 in the LRA, Section 2.1.3.4, which depicts the Braidwood Station Blackout (SBO) recovery boundary, does not show circuit breakers 1412, 1422, 2412, and 2422 between the 345-kV circuit breakers and the 4160-volt ESF buses.

Request:

a. Clarify why circuit breakers 1412, 1422, 2412 and 2422 are not included in Figure 2.1-3.

b. Confirm that all components, including breakers and disconnect switches, between the 345-kV utility grid and the 4160-volt ESF buses that are in the SBO recovery path are within the scope of license renewal.

c. Provide a revised Figure 2.1-3, as applicable, for the Byron SBO recovery boundary including all components in the SBO recovery path that shows a clear distinction between components that are within the scope of license renewal and those that are not.

Exelon Response:

a. LRA Figure 2.1-3, Braidwood Station Blackout (SBO) Recovery Boundary is a simplified representation of the Braidwood SBO recovery path. Circuit breakers 1412, 1422, 2412, and 2422 were not shown on LRA Figure 2.1-3 and circuit breakers 1413, 1414, 1423, 1424, 2413, 2414, 2423, and 2424 were shown, but not labeled on LRA Figure 2.1-3 to maintain the figure as simple as possible.

Circuit breakers 1412, 1413, 1414, 1422, 1423, 1424, 2412, 2413, 2414, 2422, 2423, and 2424 are within the scope of license renewal.

b. The components in the SBO recovery path between the 345-kV utility grid and the 4160-volt ESF buses, including breakers and disconnect switches, are within the scope of license renewal.

RS-14-091 Enclosure A Page 5 of 5 The 4160-volt ESF bus power paths from:

the normal offsite source from the 345-kV utility grid, the reserve offsite source from the 345-kV utility grid, the alternate AC source are described below using Braidwood Unit 1, 4160-volt ESF bus 141 as an example.

The normal offsite source from the 345-kV system is through the Unit 1 System Auxiliary Transformer 142-1 and then through breaker 1412 to energize the 4160-volt ESF bus 141.

The reserve offsite source from the 345-kV system is through the Unit 2 System Auxiliary Transformer 242-1 and then through breakers 2412, 2414 and 1414 to energize the 4160-volt ESF bus 141.

The alternate AC source is from the Unit 2 diesel generator DG2A through breakers 2413, 2414 and 1414 to energize the 4160-volt ESF bus 141.

The power paths for remaining Braidwood Units 1 and 2 4160-volt ESF buses are similar.

c. Consistent with this response, LRA Figure 2.1-3, page 2.1-15, is revised as shown in Enclosure B. The revised LRA Figure 2.1-3 for the Braidwood SBO recovery boundary includes circuit breakers 1412, 1422, 2412, and 2422 and labels for circuit breakers 1413, 1414, 1423, 1424, 2413, 2414, 2423, and 2424. Also, an explicit demarcation line that shows a clear distinction between components that are within the scope of license renewal and those components that are not in the scope of license renewal is added to LRA Figure 2.1-3.

RS-14-091 Enclosure B Page 1 of 3 Enclosure B Byron and Braidwood Stations, Units 1 and 2 License Renewal Application (LRA) updates resulting from the responses to the following RAIs:

RAI 2.1.3.4-1 RAI 2.1.3.4-3 Note: To facilitate understanding, the original LRA Figure 2.1-2, page 2.1-14 and Figure 2.1-3, page 2.1-15 have been repeated in this Enclosure, with revisions indicated. Original LRA text is shown in normal font. Changes originating from this letter and from Exelon letter RS-13-273, dated December 17, 2013 are highlighted with bolded italics for inserted text.

RS-14-091 Enclosure B Page 2 of 3 As a result of the updated response to RAI 2.1.3.4-1 provided in Enclosure A of this letter, and the original response to RAI 2.1.3.4-2 provided in Enclosure A of Exelon letter RS-13-273, LRA Figure 2.1-2, "Byron SBO Recovery Boundary," page 2.1-14, is revised as shown below:

Figure 2.1-2

RS-14-091 Enclosure B Page 3 of 3 As a result of the updated response to RAI 2.1.3.4-3 provided in Enclosure A of this letter, and the original response to RAI 2.1.3.4-4 provided in Enclosure A of Exelon letter RS-13-273, LRA Figure 2.1-3, page 2.1-15, "Braidwood SBO Recovery Boundary," is revised as shown below:

Figure 2.1-3