NRC 2009-0085, License Amendment Request 241 Alternative Source Term Response to Request for Additional Information

License Amendment Request 241 Alternative Source Term Response to Request for Additional Information

ML092520547
Person / Time
Site:	Point Beach
Issue date:	09/04/2009
From:	Meyer L Point Beach
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LAR 241, NRC 2009-0085
Download: ML092520547 (20)

Text

September 4,2009 NRC 2009-0085 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units Iand 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 License Amendment Request 241 Alternative Source Term Res~onseto Request for Additional lnformation

References:

(1) FPL Energy Point Beach, LLC letter to NRC, dated December 8,2008, License Amendment Request 241, Alternative Source Term (ML083450683)

(2) NRC letter to NextEra Energy Point Beach, LLC, dated August 13, 2009, Point Beach Nuclear Plant, Units Iand 2 - Request for Additional lnformation from Accident Dose Branch RE: Alternate Source Term (TAC Nos. ME0219 and ME0220) (MLO92151123)

NextEra Energy Point Beach, LLC (NextEra) submitted License Amendment Request (LAR) 241 (Reference 1) to the NRC pursuant to 10 CFR 50.90. The license amendment would revise the current licensing basis to implement the alternative source term (AST) through reanalysis of the radiological consequences of the Point Beach Nuclear Plant (PBNP) Final Safety Analysis Report Chapter 14 accidents.

Via Reference (2), the NRC staff determined that additional information was required to enable the staff's review of the proposed amendment. Enclosure 1 provides the NextEra response to this request. Enclosure 2 provides a more readable version of the Site Plan drawing presented in Reference (I), supporting the response to Question 4. Enclosure 3 provides plant drawings used in the limiting atmospheric dispersion factor (YQ) calculations, supporting the response to Question 5.

This letter contains no new regulatory commitments and no revisions to existing commitments.

The information contained in this letter does not alter the no significant hazards consideration contained in Reference (1) and continues to satisfy the criteria of 10 CFR 51.22 for categorical exclusion from the requirements for an environmental assessment.

NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241

Document Control Desk Page 2 In accordance with 10 CFR 50.91, a copy of this letter is being provided to the designated Wisconsin Official.

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

Executed on September 4,2009.

Very truly yours, NextEra Energy Point Beach, LLC Enclosures cc: Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW

ENCLOSURE I NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 LICENSE AMENDMENT REQUEST 241 ALTERNATIVE SOURCE TERM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION The NRC staff determined that additional information was required (Reference 1) to enable the Accident Dose Branch to complete the review of License Amendment Request (LAR) 241, Alternative Source Term (AST) (Reference 2). The following information is provided by NextEra Energy Point Beach, LLC (NextEra) in response to the NRC staff's request.

Question I Please provide additional information explaining the need for the control room ventilation system (VNCR) accident mode in mitigatingpostulated post-design-basis accident activity releases in lieu of a Technical Specification controllable safety-related system.

In addition, please provide information on any other mitigating systems (safety-related or otherwise) that will or can be used for control room isolation.

NextEra Response The control room emergency filtration system (CREFS) is the portion of the control room ventilation (VNCR) system that supports the radiological habitability requirements of 5 rem total effective dose equivalent (TEDE) dose limit to the control room operators, set forth in 10 CFR 50.67. The CREFS system is classified as augmented quality (or quality related), and has the following characteristics:

1. CREFS is required to be operable per Technical Specification (TS) 3.7.9, Control Room Emergency Filtration System.

2. CREFS is within the scope of the Maintenance Rule Program (10 CFR 50.65) and License Renewal (10 CFR 54.37(b)). Inclusion within the scope of License Renewal results in monitoring of the material condition of the CREFS ductwork and supports per the requirements of the associated aging management programs.

3. CREFS is powered by safety-related sources.

4. CREFS is designated with an augmented quality status. This means the design control, procurement, maintenance, and operational activities fall under the 10 CFR 50, Appendix B Quality Assurance Program.

Page 1 of 7

5. LAR 241, Enclosure 3 (Reference 2) provided details on the extensive modifications that have been or will be made to CREFS to improve its reliability. CREFS modifications include actuation signal diversity and redundancy, active component redundancy, emergency diesel generator (EDG) auto-start capability, accident mode damper alignment, damper change to fail open operation, boundary isolation dampers upgraded to bubble-tight leakage classification, and hard casting of ductwork seams.

6. With respect to the potential compliance of CREFS with 10 CFR 50.49, Environmental Qualification of Electric Equipment Important to Safety for Nuclear Power Plants, CREFS components being credited in Reference (2) and their locations were reviewed against the environmental conditions (radiological, temperature, and pressure) that would exist in those areas following design basis accidents. Based on the results of this review, certain components were determined to be located in areas classified as harsh environments from a radiological perspective. Accordingly, the following components will be added to the 10 CFR 50.49 program:

e Power and control cables for control room recirculation fan motor W-13Bl-M e Power and control cables for control room recirculation fan motor W-I 3B2-M e Power and control cables for control room charcoal filter fan motor W-I 4A-M e Power and control cables for control room charcoal filter fan motor W-I 4B-M The above changes are being implemented as part of the AST modifications. The remainder of the CREFS components were determined to be located in mild environments and thus, did not need to be included in the 10 CFR 50.49 program.

7. As indicated in the public meeting with the NRC on August 6, 2009 (ML092190563), NextEra will provide a Regulatory Commitment by separate correspondence to seismically verify CREFS and implement modifications, if required, consistent with the approach approved by the NRC for the Hatch turbine building ventilation system in letter dated August 28, 2008 (Reference 3).

Based on the above, NextEra has concluded that sufficient assurance is provided that CREFS will perform its credited function.

There are no other mitigating systems that will or can be used for control room isolation. CREFS Accident Mode (Mode 5) is initiated either manually by the control room operator, automatically as a result of a safety injection signallcontainment isolation signal, or automatically as a result of a high radiation signal generated by the control room area monitor or the control room duct noble gas monitor.

Page 2 of 7

Question 2 In Enclosure 3, Section 6.5, page 45 of the submittal, there is a discussion on primary-to-secondary leakage release pathway for the control rod ejection accident (CRDE) analysis. In the first paragraph it states that primary-to-secondary steam generator (SG) tube leakage is assumed to continue until 2000 seconds, or 0.556 hours0.00644 days <br />0.154 hours <br />9.193122e-4 weeks <br />2.11558e-4 months <br />, when the primary system pressure is less than the secondary system pressure. However, in the following paragraph it states that primary-to-secondary SG leakage is assumed to be 1000 gpm for the duration of the accident.

Please provide which value was used to evaluate the radiological consequences of a CRDE event, NextEra Response The duration value used to evaluate the radiological consequences of a control rod ejection accident (CRDE) event for a primary-to-secondary leak rate of 1,000 gramslmin (gmlmin) per steam generator (SG) is 2000 seconds. In LAR 241, Enclosure 3 (Reference 2), the discussion of primary-to-secondary SG leakage duration correctly states the duration of 2,000 seconds in the first paragraph on Page 45. This information is also correctly shown in Reference (2), Enclosure 3, Table 22.

The second paragraph of Reference (2), Enclosure 3, on Page 45, is revised, via this letter, to state the following:

"As discussed in Section 2.2 of this enclosure, a primary-to-secondary leak rate of 1,000 gmlmin per SG is assumed to occur for 2,000 seconds."

Question 3 The safety evaluation associated with Point Beach Unit Iand Unit 2, Amendment Nos, 213 and 218, respectively (Agencywide Documents Access and Management System (ADAMS) Accession No. ML040680918), dated April 02, 2004, suggested that the meteorological measurementprogram was to be upgraded in the post 1999 timeframe. Were the September 2000, through September 2005, meteorological data provided in the December 8, 2008, Point Beach Alternative Source Term License Amendment Request (LAR) measured under the upgraded program? If so, please highlight the upgrades and discuss the current program's capability to assess the Point Beach site meteorology, particularly with respect to atmospheric stability and wind flow.

NextEra Response Meteorological data from September 2000 through September 2005 was measured with the upgraded equipment. Improvements were made to the meteorological measurement program from December 1999 to December 2005. Included in the equipment upgrade was the replacement of all three meteorological towers, replacement of the meteorology data recorders and wind speed sensor, and repair of the wind speed and temperature indicators.

In February 2006, an analysis of the meteorological data from September 2000 through September 2005 (Reference 4) was performed. The following tables show the results from that analysis. The meteorological data used in the atmospheric dispersion factor (xIQ) calculations meet the requirements of Regulatory Guide (RG) I.I 94 (Reference 5) of data recovery of at least 90% on Page 3 of 7

an annual basis. These acceptable results provide assurance that the current program is capable of assessing the PBNP site meteorology, including atmospheric stability and wind flow.

Missing Data Recovered Year Missing Hours Total hours  % Recovery Hours 2000* I 2711 2712 99.96%

2001 585 8175 8760 93.32%

2002 41 8719 8760 99.53%

2003 29 8731 8760 99.67%

Out of Ranae Data Year Invalid Hours Valid Hours Total hours  % Recovery 2000" 4 2708 2712 99.85%

2001 118 8642 8760 98.65%

2002 53 8707 8760 99.39%

2003 157 8603 8760 98.21%

2004 53 8731 8784 99.19%

2005** 128 6424 6552 98.04%

Insufficient Variation (Straight-lining) Data Year I Invalid Hours I Valid Hours I Total hours I  % Recovery I Total Invalid Data*

Year Invalid Hours Valid Hours Total hours  % Recovery 2000" 159 2553 2712 94.08%

2001 796 7964 8760 90.91%

• for four months of data collection

• • for nine months of data collection

• • • Total lnvalid Data results may not be additive, because an hour of data may be invalid for more than one reason Page 4 of 7

Question 4 What is the relationship of "called north" to true north for the Point Beach site? Nuclear Regulatory Commission (NRC) staff examined Figure 2 of Enclosure 3 to the December 8, 2008, Point Beach LAR, but had difficulty reading the figure because it had been reduced in size.

NextEra Response Table A-2 of RG 1.I 94 (Reference 5) states, "Note: some facilities have a 'plant north' shown on site arrangement drawings that is different from 'true north.' The direction entered must have the same point of reference as the wind directions reported in the meteorological data." The words

'called north' at PBNP are used interchangeably with the words 'plant north,' as described in Reference (5).

A more readable version of the drawing presented in Reference (2), Enclosure 3, Figure 2, shows that "true north" is located 24" 43' rotated east of "called north." Therefore, 25" is subtracted from the directions determined from the plant drawings using "called north." The release point direction determined from a drawing using "called north" is therefore adjusted to "true north," accordingly. This approach is consistent with the guidance contained in RG I.I94 (Reference 5). includes a more readable version of the Site Plan drawing presented in Reference (2), , Figure 2.

Question 5 Please provide a further discussion of why it is acceptable to use the control room atmospheric dispersion factors (X/Q values) for dose estimates associated with unfiltered inleakage into the control room envelope. Where is the control room located with respect to the postulated release locations shown in the figures provided as part of the December 8, 2008, LAR?

NextEra Response For the control room X/Q calculations, the receptor is the control room fresh air intake for each release location. This receptor location is also used for unfiltered inleakage. The source-to-receptor distance was determined by the shortest horizontal distance between the release points and the control room air intake. This approach is consistent with Section 3.4 of RG 1.I 94 (Reference 5).

The detailed plant drawings used in the limiting X/Q calculations are included in Enclosure 3.

Drawings M-1 and M-2001 in Enclosure 3 show the locations of the control room with respect to the postulated release locations for Unit 1 and Unit 2, respectively.

Page 5 of 7

Question 6 NRC staff notes that inputs to the ARCON96 computer code were provided for the release locations identified as the limiting cases. Other than for the refueling water storage tank, did you make quantitative calculations for other possible releases (e.g., from Unit I) or was the determination of which releases were limiting based upon a subjective assessment? Please confirm that the generated / Q values model the limiting doses and all potential release scenarios were considered, including those due to single failures.

NextEra Response Thirteen specific release-receptor combinations for XjQ values were calculated to determine the limiting release locations:

Unit IContainment Wall (Diffuse Source) to Control Room Air lntake Unit 2 Containment Wall (Diffuse Source) to Control Room Air lntake Unit 1 Containment Facade (Point Source) to Control Room Air lntake Unit 2 Containment Facade (Point Source) to Control Room Air lntake Auxiliary Building Vent Stack (ABVS) to Control Room Air lntake Drumming Area Vent Stack (DAVS) to Control Room Air lntake Unit IA Main Steam Safety Valves (MSSVs) to Control Room Air lntake Unit IB MSSVs to Control Room Air lntake Unit 2 A MSSVs to Control Room Air lntake Unit 2 B MSSVs to Control Room Air lntake Spent Fuel Pool to Control Room Air lntake Unit 1 Purge Stack to Control Room Air lntake Unit 2 Purge Stack to Control Room Air lntake A quantitative calculation for other possible release points was performed, including from Unit 1. The results of the 95thpercentile XjQ values for the various release points are summarized in the table below.

Atmospheric Dispersion Factors (XJQ) for Control Room Habitability (seclm3)

Release Path 0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 2 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1 to 4 days 4 to 30 days U l Containment I.06E-03 8.12E-04 3.31E-04 2.70E-04 2.13E-04 U2 Containment 1.39E-03 9.80E-04 3.84E-04 3.46E-04 3.02E-04 U l Fa~ade 7.44E-03 5.76E-03 2.30E-03 1.85E-03 I.44E-03 U2 Fa~ade 1.87E-02 I.50E-02 5. I1E-03 4.94E-03 4.23E-03 ABVS 1.80E-03 1.31E-03 5.15E-04 4.03E-04 3.03E-04 DAVS 1.63E-03 1.28E-03 4.58E-04 3.92E-04 3.03E-04 U l A MSSVS 2.97E-03 2.22E-03 8.44E-04 6.74E-04 5.1 7E-04 U l B MSSVS 2 12~-03 I.56E-03 6.05E-04 4.75E-04 3.59E-04 U2 A MSSVS 4.66E-03 3.40E-03 I. 17E-03 I.07E-03 9.05E-04 U2 B MSSVS 3.94E-03 2.98E-03 1.IOE-03 9.62E-04 8.42E-04 Spent Fuel Pool 2.19E-03 1.88E-03 7.14E-04 6.37E-04 5.50E-04 U l Purge 3. I4E-03 2.30E-03 8.94E-04 7.01 E-04 5.31 E-04 U2 Purge 6.94E-03 5.30E-03 1.93E-03 1.69E-03 1.46E-03 Page 6 of 7

These locations generated the most conservative X/Q values for the intended application and all potential release scenarios were considered, including those due to single failures, consistent with the guidance contained in Section 3.2 of RG 1.I 94 (Reference 5). The releases are conservatively treated as ground-level, as none of the above releases are of sufficient height to escape the aerodynamic effects of the plant buildings (i.e., 2.5 times the containment building height).

References (I) NRC letter to NextEra Energy Point Beach, LLC, dated August 13, 2009, Point Beach Nuclear Plant, Units Iand 2 - Request for Additional Information from Accident Dose Branch RE:

Alternate Source Term (TAC Nos. ME0219 and ME0220) (ML092151123)

(2) FPL Energy Point Beach, LLC letter to NRC, dated December 8, 2008, License Amendment Request 241, Alternative Source Term (ML083450683)

(3) NRC letter to Edwin I. Hatch Nuclear Plant, dated August 28, 2008, Edwin I. Hatch Nuclear Plant, Unit Nos. 1 and 2, Issuance of Amendments Regarding Alternate Source Term (TAC Nos. MD2934 and MD2935) (ML081770071)

(4) FPL Energy Point Beach, LLC letter to NRC, dated December 8, 2008, Transmittal of ARCON96 and RADTRAD CDs Supporting Alternative Source Term License Amendment Request 241 (ML083650282)

(5) Regulatory Guide 1.I 94, Atmospheric Relative Concentrations for Control Room Radiological Habitability Assessments at Nuclear Power Plants, dated June 2003 (ML031530505)

Page 7 of 7

ENCLOSURE 2 NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 SITE PLAN DRAWING Ipage follows

ENCLOSURE 3 NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS IAND 2 PLANT DRAWINGS USED IN THE LIMITING ATMOSPHERIC DISPERSION FACTOR (xIQ)CALCULATIONS 8 pages follow