NL-07-1948, Additional Information to Support Acceptance Review of Request to Change Maximum Power Level

Additional Information to Support Acceptance Review of Request to Change Maximum Power Level

ML072850108
Person / Time
Site:	Vogtle
Issue date:	10/09/2007
From:	Stinson L Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-07-1948
Download: ML072850108 (8)

Text

L.M. Stinson (Mike) Southern Nuclear Vice President Operating Company. Inc.

Fleet Operations Support 40 Inverness Center Parkway Post Office Box 1295 Birmingham, Alabama 35201 Tel 205.992.5181 Fax 205.992.0341 SE SOUTHERN October 9, 2007 COMPANY Energy to Serve Your World' Docket Nos.: 50-424 NL-07-1948 50-425 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant Additional Information to Support Acceptance Review of Request to Change Maximum Power Level Ladies and Gentlemen:

By way of letter NL-07-1020, dated August 28, 2007, Southern Nuclear Operating Company (SNC) submitted an application to change the Maximum Power Level of Vogtle Electric Generating Plant (VEGP) Units 1 and 2. On October 2, 2007, in a phone call between SNC and the Staff, SNC was requested to provide additional information to support the acceptance review of the radiological analyses described in the application.

As requested by the Staff, SNC is providing the following information regarding the calculation of relative atmospheric dispersion factor (x/Q) values at the Main Control Room air intakes following a loss-of-coolant accident.

1. The annual periods for the meteorological data are 1998, 1999, and 2000.

2. Meteorological data used in the ARCON96 analyses are located on the enclosed CD (Enclosure 1) in the folder named "Met Data."

3. The ARCON96 input data are located on the enclosed CD in the folder named "Input Files." This folder also contains a file named "ARCONInput Output Fname.xls" that cross-references the names of the input and output files with the individual ARCON96 cases.

4. For VEGP, the release mode is "ground level" as described in VEGP UFSAR Section 15A.1.

5. The source-receptor configuration details are provided in Enclosure 2.

The information is excerpted from the SNC calculation for determining the x/Q values at the Main Control Room air intakes.

U. S. Nuclear Regulatory Commission NL-07-1948 Page 2

6. Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) distances are not being provided because offsite x/Q values were not recalculated.

7. The ARCON96 output data are located on the enclosed CD in the folder named "Output Files."

8. The current x/Q values are reported in Table 15A-2 of the VEGP UFSAR.

The current and revised x/Q values are also reported in Table 111-2 in Enclosure 5,Section III, of the application to change the Maximum Power Level of VEGP Units 1 and 2 referenced above.

Mr. L. M. Stinson states he is a Vice President of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and to the best of his knowledge and belief, the facts set forth in this letter are true.

This letter contains no NRC commitments. If you have any questions, please advise.

Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY L. M. Stinson Vice President Fleet Operations Support Swqrn to and subscribedbefore me this 7 day of 7,, 2007.

Notary Public My commission expires: 3~2010 LMS/RJF/daj

Enclosures:

1. CD Containing ARCON96 Files

2. Source-Receptor Configuration Details

U. S. Nuclear Regulatory Commission NL-07-1948 Page 3 cc: Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, Vice President - Vogtle Mr. D. H. Jones, Vice President - Engineering RType: CVC7000 U. S. Nuclear Regulatory Commission Dr. W. D. Travers, Regional Administrator Mr. S. P. Lingam, NRR Project Manager - Vogtle Mr. G. J. McCoy, Senior Resident Inspector - Vogtle State of Georgia Mr. N. Holcomb, Commissioner - Department of Natural Resources

Vogtle Electric Generating Plant Additional Information to Support Acceptance Review of Request to Change Maximum Power Level Enclosure 1 CD Containing ARCON96 Files

Vogtle Electric Generating Plant Additional Information to Support Acceptance Review of Request to Change Maximum Power Level Enclosure 2 Source-Receptor Configuration Details

Design Calculations - Nuclear Southern Company ServicesA IProject Vogtle Units 1 and 2 ICalcuon X6CHA.01.00Number Subject/Title Main Control Room and Technical Support Center Air Intake X/Q Estimates Shed [6] of [10]

Distance between FHB and CR air intake FHBs are located between two reactor buildings with a roof elevation of 288'2". The FHB releases were assumed to occur at the roof, where the distance to the CR air intake is the shortest. This shortest distance is same to Units 1 and 2 air intakes when the release locations are located at the east and west comer of the FHB.

Total source-to-receptor distance = 8085.25 ft - 7998.5 ft + 19.25 ft = 106 ft = 32.3 m Where 19.25 ft is the distance between Row CD and the CR intake, and 8085.25 ft and 7998.5 ft are the locations of Rows CD and FA, respectively (Drwg. IX4DE312, Ver. 11.0). The vertical distance between the FHB roof and the CR intake is:

FRB roof height - CR air intake height = 288.17' - 283' = 5.17 ft The distance between Unit 1 CR intake and Unit 1 FHB release point is shorter than the distance between Unit 1 CR intake and Unit 2 FHB release point. Similarly, the distance between Unit 2 CR intake and Unit 2 FHB release point is shorter than that between Unit 2 CR intake and Unit I FHB release point. Only the expected worst case distances were presented regarding the FHB releases. It is the case involving Unit 1 CR intake and the east comer FHB release. The case involving Unit 2 CR intake and west comer FHB releases will produce results that are identical to the case with Unit 1. All the above source-to-receptor distances were used in the ARCON96 runs. Distances between the release points and air intakes are presented below.

Receptor: Unit 1 CR Air Intake Horizontal, Vertical Direction to Source Release Point Distance (ft) Distance (ft) Straight-Line Distance degree)

Unit 1 Ft m Containment 72 0 72.0 21.9 135 Hatch Door 275 -54.5 280.3 85.5 135 FHB 106 5.17 106.1 32.3 180 Unit 2 Containment 189 0 189.0 57.6 247 Hatch door 363 -54.5 367.1 111.9 243 Receptor: Unit 2 CR Air Intake Horizontal Vertical Direction to Source Release Point Distance (ft) Distance (ft) Straight-Line Distance (degree)

Unit I ft m Containment 189 0 189.0 57.6 73 Hatch Door 363 -54.5 367.1 111.9 118 Unit 2 Containment 72 0 72.0 21.9 226 Hatch door 275 -54.5 280.3 85.5 225 FHB 106 5.17 106.1 32.3 180

Design Calculations - Nuclear Southern Company ServicesA Project Calculation Number Vogtle Units I and 2 X6CHA.01.00 Subject/Title Main Control Room and Technical Support Center Air Intake X/Q Estimates Sheet [7] of [ 10]

Receptor: TSC Air Intake .

Horizontal Vertical Direction to Source Release Point Distance (ft) Distance (ft) Straight-Line Distance (degree)

Unit 1 ft m Containment 81 0 81.0 24.7 173 Hatch Door 240 -5.75 240.1 73.2 161 Unit 2 Containment 283 0 283.0 86.3 246 Hatch door 455 -5.75 455.0 138.7 243 The elevations of air intakes and release points are presented in the following table.

Location Elevation (ft)

CR Intake 283 TSC Intake 234.25 Hatch Door 228.5 FHB Roof 288.17 Note: The grade elevation is 220 ft.

It should be noted that for the postulated FHB releases, besides the cases presented above, four other scenarios were also analyzed. They are 1) east comer release - Unit 2 CR intake; 2) west comer release - Unit 1 CR intake; 3) mid-point release - Unit I CR intake; and 4) mid-point release - Unit 2 CR intake. The mid-point is assumed to be located in the middle of the line connecting east and west comer release points. The above 4 scenarios all have their "intake to source" distances larger than that of the east comer release and Unit 1 CR intake (or west comer release and Unit 2 CR intake). They were considered to ensure that the meteorological conditions associated with the specific wind direction window would not cause the X/Qs to become greater than the cases presented in this calculation.

5.4 Effective Wind Directions The direction to the source from the intake and "wind direction window width" are part of the input requirements for the ARCON96 program. As suggested in NUREG/CR-6331 (1997), the wind direction window sector size was chosen as the direction from the receptor to the source, +/-450. The "direction to source" for each combination of release point and receptor (air intake) is presented in the table shown in Sheets 5 and 6.

5.5 Building Areas Building areas used for wake analysis were calculated based on the assumptions described in Section 4.3.

Design Calculations - Nuclear Southern Company Services A I Proct Vogtle Units 1 and 2 X6CHA.01.00 Calculation Number Subject/Title Main Control Room and Technical Support Center Air Intake X/Q Estimates Sheet [10] of [10]

Figure 1 Air Intake Locations and Release Points Hatch Door TSC Intake 0 North Unit I CR Intake FHB Release Pt. x 0

Fuel Handling Building (Units 1 & 2) 0 Unit 2 CR Intake Hatch Door Note: Release point from the reactor was a point on the containment surface closest to the receptor location.