ML100630792

E-mail Byron 1 & 2 - Request for Additional Information for One-Time Extension of ESW Train Completion Time (ME2293-94)

ML100630792
Person / Time
Site:	Byron
Issue date:	03/03/2010
From:	David M Plant Licensing Branch III
To:	Schofield L, Simpson P Exelon Corp
marshall david 415-1547
References
TAC ME2293, TAC ME2294
Download: ML100630792 (3)

Text

From: David, Marshall Sent: Wednesday, March 03, 2010 4:17 PM To: patrick.simpson@exeloncorp.com; Lisa.Schofield@exeloncorp.com Cc: Campbell, Stephen; Purciarello, Gerard

Subject:

BYRON 1 & 2 - RAI FOR ONE-TIME EXTENSION OF ESW TRAIN COMPLETION TIME (ME2293-94)

Importance: High Pat, Lisa, Below are additional questions on the subject license amendment request. I will be placing a copy of this e-mail into ADAMS.

Thanks, Marshall REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNIT NOS. 1 AND 2 DOCKET NOS. STN 50-454 AND STN 50-455 The Nuclear Regulatory Commission (NRC) staff is reviewing Exelon Generation Company, LLCs (the licensees) license amendment request (LAR) dated September 24, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092680090), as supplemented by letters dated November 13, 2009 (ADAMS Accession No. ML093200065), January 19, 2010 (ADAMS Accession No. ML100200075), and March 1, 2010 (ADAMS Accession No. ML100610109). The LAR requests a one-time extension of the Completion Time (CT) to restore a unit-specific essential service water train to operable status for Technical Specification Limiting Condition for Operation 3.7.8, Essential Service Water (SX)

System, from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br />.

The NRC staff has determined that the following additional information is required to complete its review. Your staff has agreed to provide the requested information by March 9, 2010.

The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for NRC staff review and contribute toward the NRCs goal of efficient and effective use of NRC staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1547.

Question 1 In Reference 1, the licensee responded to Question 1.a by stating, EGC has evaluated the crosstied SX train configuration and concluded that a single SX pump is capable of providing adequate cooling water to both trains of SX loads under normal and accident conditions. The NRC staff requests more information about the above mentioned evaluation. Specifically,

1. Is the licensees evaluation based on a safety-related calculation?

2. Does the licensees evaluation/calculation consider all design basis accidents and all normal and transient events including loss of offsite power, for which the SX system must perform?

Explain.

3. Does the evaluation/calculation consider SX system degradation as determined by the licensees test and maintenance program for the SX system? Explain.

4. Does SX flow test data support the conclusions of the evaluation/calculation? Explain.

Question 2 For defense in depth considerations the NRC staff asked Question 8 in Reference 2. In response to Question 8.c, the licensee stated in Reference 3 that, If the Unit 1 (i.e. the operating unit) SX pump were lost during the extended CT, Byron Abnormal Operating Procedure 1BOA PRI-7 provides guidance on aligning Unit 2 (i.e., the shutdown unit) SX to Unit 1 SX through the unit crosstie valves, 1/2SX005. Aligning Unit 2 SX to Unit 1 SX will provide SX to the Unit 1 EDGs [emergency diesel generators].

In Section 2.1 of Attachment 5 of Reference 4, the licensee stated, A best estimate flow analysis has shown that a single pump can provide cooling to all loads on both units with the exception of the Reactor Containment Fan Coolers (RCFC) and Emergency Diesel Generators (EDGs) on the unit without an SX pump and one train of RCFCs on the unit with an available SX pump.

Considering these two statements, it is not clear whether the 2B SX pump could be used to supply cooling to the Unit 1 EDGs. Please explain.

References:

1. Exelon submittal for Byron Station, Units 1 and 2, Additional Information Supporting License Amendment Request for a One-Time Extension of the Essential Service Water Train Completion Time, dated March 1, 2010.

2. Letter from M. J. David (U. S. Nuclear Regulatory Commission) to C. G. Pardee (Exelon Generation Company, LLC), "Byron Station, Unit Nos. 1 and 2 Request for Additional Information Related to One-Time Extension of Essential Service Water Train Completion Time (TAC Nos. ME2293 and ME2294)," dated December 18, 2009.

3. Exelon submittal for Byron Station, Units 1 and 2, Additional Information Supporting License Amendment Request for a One-Time Extension of the Essential Service Water Train Completion Time, dated January 19, 2010.

4. Exelon submittal for Byron Station, Units 1 and 2, License Amendment Request for a One-Time Extension of the Essential Service Water Train Completion Time, dated September 24, 2009.

E-mail Properties Mail Envelope Properties (0046140293E11F408991442DB4FE25CA068C45A021)

Subject:

BYRON 1 & 2 - RAI FOR ONE-TIME EXTENSION OF ESW TRAIN COMPLETION TIME (ME2293-94)

Sent Date: 3/3/2010 4:17:34 PM Received Date: 3/3/2010 4:17:34 PM From: David, Marshall Created By: Marshall.David@nrc.gov Recipients:

patrick.simpson@exeloncorp.com (patrick.simpson@exeloncorp.com)

Tracking Status: None Lisa.Schofield@exeloncorp.com (Lisa.Schofield@exeloncorp.com)

Tracking Status: None Stephen.Campbell@nrc.gov (Campbell, Stephen)

Tracking Status: None Gerard.Purciarello@nrc.gov (Purciarello, Gerard)

Tracking Status: None Post Office:

HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 26126 3/3/2010 Options Expiration Date:

Priority: olImportanceHigh ReplyRequested: False Return Notification: False Sensitivity: olNormal Recipients received: