NRC 2009-0090, License Amendment Request 241, Alternative Source Term, Response to Request for Additional Information
| ML092540144 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 09/10/2009 |
| From: | Meyer L Nextera Energy, Point Beach |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC 2009-0090 | |
| Download: ML092540144 (14) | |
Text
NEXBera TM ENERGY@ y== POINT BEACH September 10,2009 NRC 2009-0090 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 Reauest 241 Alternative Source Term Res~onseto Reauest for Additional Information
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 FPL Energy Point Beach, LLC, dated August 26,2009, Point Beach Nuclear Plant, Units Iand 2 - Request for Additional lnformation from Containment and Ventilation Branch Related to the Proposed Alternate Source Term Amendment (TAC Nos. ME0219 and ME0220) (ML092360535)
NextEra Energy Point Beach, LLC (NextEra) submitted License Amendment Request (LAR) 241 (Reference I ) 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 (FSAR) Chapter 14 accidents.
The NRC staff determined that additional information was required (Reference 2) to enable the staff's review of the amendment request. Enclosure 1 provides the NextEra response to this request for additional information. Enclosure 2 provides marked up boundary drawings for the control room emergency filtration system (CREFS) and the primary auxiliary building ventilation (VNPAB) system supporting the NextEra response to Question SCVB#l. Enclosure 3 lists augmented quality (quality related) equipment for CREFS and VNPAB supporting the NextEra response to Question SCVB#1.
This letter contains no new regulatory commitments and no revisions to existing commitments.
NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241
Document Control Desk Page 2 The information contained in this letter does not alter the no significant hazards consideration contained in Reference ( I ) and continues to satisfy the criteria of 10 CFR 51.22 for categorical exclusion from the requirements for an environmental assessment.
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 10, 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 I AND 2 LICENSE AMENDMENT REQUEST 241 ALTERNATIVE SOURCE TERM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION The NRC staff determined that additional information is required (Reference I ) to enable the Staffs 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 SCVB#?
Provide the extent of the control room emergency filfration system (CREFS) and the primary auxiliary building ventilation system (VNPAB) that would be required to be functional to supporf the alternate source term (ASg licensing amendment request (LAR) by providing drawings suitably marked with the system boundaries and a list of structures, systems, and components that would be upgraded to augmented quality status. Include in the response, all new equipment that will be added to modify the CREFS and VNPAB to provide redundancy along with a discussion of the quality status to which such equipment will be designed, procured, installed and tested.
NextEra Response Drawings marked to show the system boundaries for the control room emergency filtration system (CREFS) and the primary auxiliary building ventilation (VNPAB) system are provided in . Structures, systems, and components that will be classified as augmented quality (quality related) for CREFS and VNPAB are listed in Enclosure 3.
New equipment that will be added or replaced to modify the CREFS and the VNPAB system to provide redundancy is listed below:
CREFS 8 FS-4133A (W-I 3BllB2 control room recirculation fan low alarm flow switch)
ID TS-4844A (HX-IOONB control room chilled water cooling coil temperature switch) 8 W-13BllB2 and W-14NB fan control circuits 0 VNCR-4851CID (W-14AIB control room charcoal filter fan discharge control dampers)
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VNPAB 0 VNPAB-3248 and VNPAB-3249 (W-21NB PAB exhaust stack fan discharge control dampers being replaced by backdraft dampers) e VNPAB-3265 and VNPAB-3266 (W30NB PAB exhaust filter fan discharge control dampers being replaced by backdraft dampers)
This equipment will meet the requirements of NextEra's augmented quality status. Design control, procurement, installation, testing, operation and maintenance of the equipment will fall under NextEra's 10 CFR 50, Appendix B, Quality Assurance Program.
Question SCVB#2a The CREFS consists of a single filfer train with redundant fans. It was stated that four control room ventilation fans, which include the two CREFS fans, will auto-stan' on the emergency diesel generators upon receipt of a containment isolation signal or high radiation signal. Provide the following information:
2a. When both the CREFS fans are operating in parallel, discuss the maximum air flow through the filter system and the performance of the emergency air filter with particular attention to residence time for the charcoal filter and the assumptions used in the accident analysis.
NextEra Response The two CREFS emergency fans will not operate in parallel. Therefore, there will be no change in the original design as a result of the AST modification. Although the CREFS emergency and recirculation fans will be included in the emergency diesel generator loading profile for automatic starting, interlocks will only permit one emergency fan and one recirculation fan to operate at one time which results in an air flow of 4,950 cubic feet per minute (cfrn) 210%.
Maximum air flow through the filter system with one CREFS recirculation fan and one emergency fan operating is 4,950 cfrn +lo%, or 5,445 cfm. The filter system is designed for the flow of one emergency fan, and the performance of the emergency high efficiency particulate air (HEPA)lcharcoal filter will not be compromised. The accident analysis assumes a minimum total flow rate of 4,950 cfrn -lo%, or 4,455 cfm, to maximize radiological releases. Filter residence time and filter testing is based on a flow rate of 4,950 cfrn 210% through the emergency HEPNcharcoal filter unit.
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Question SCVB#2b 2b. For the situation when all four control room ventilation fans (ie.,
. the two control building heating, ventilation, and air conditioning (HVAC) fans and the two CREFS fans) are auto-started, discuss the pressure changes that could occur through the ductwork on a four-fan operation versus two-fan operation (i.e. one control building HVAC fan and one CREFS fan) and the capability of the ductwork to withstand these conditions. Describe the construction and leakage characteristics of the ductwork, potential for unfiltered in-leakage of air that could occur, and its impact on the accident analysis using the AST.
NextEra Response The two CREFS emergency fans and the two recirculation fans will not auto-start together. As stated in NextEra's response to Question SCVB#2a, interlocks only permit one CREFS emergency fan and one recirculation fan to operate at one time. The system is designed for the pressure changes that occur through the ductwork for this two-fan operation, and the ductwork is capable of withstanding these pressure changes. The ductwork is constructed in accordance with Sheet Metal and Air Conditioning Contractors National Association, Duct Manual and Sheet Metal Construction for Ventilating and Air Conditioning Systems (SMACNA). The system is tested per Technical Specification (TS) 3.7.9, Control Room Emergency Filtration System (CREFS), to ensure proper operation. Additionally, tracer gas testing on the control room envelope (CRE) was completed in 2003, and the control room unfiltered air in-leakage results were within the limit assumed in the AST dose analysis.
Question SCVB#Zc 2c. Describe, according to the emergency operation procedures, how long all four fans will operate until operator action secures one train of fans. Indicate if any other operator actions are also required by any of the emergency operation procedures and the priority of stopping one train of fans relative to the other operator actions.
NextEra Response As stated in NextEra's response to Question SCVB#2a, interlocks will only permit one CREFS emergency fan and one recirculation fan to operate at one time. There is no priority or requirement established for stopping the operating fans.
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Question SCVB#3 Technical specification (TS) sun/eillance Requirement 3.7.9.6 requires verification that each CREFS emergency fan can maintain a positive pressure of 20.125 inches water gauge in the control room envelope (CRE), relative to the adjacent turbine building during the emergency mode of operation. For the AST amendment, is the CRE required to be pressurized with respect to any other adjacent spaces, including spaces above and below the CRE? If not, providejustification.
NextEra Response The CRE is surrounded by the turbine building, cable spreading room (below the CRE), and CREFS mechanical room (above the CRE), and is required to be pressurized with respect to these three areas. The cable spreading room is cooled by the cable spreading room ventilation (VNCSR) system. During normal operation and design basis events, the VNCSR system will be operating in the recirculation mode and as a result, pressure in the cable spreading room will be controlled by turbine building pressure. The CREFS mechanical equipment room is cooled by CREFS during normal operation and design basis events. The CREFS air flow into the room exits into the turbine building, resulting in the pressure in the room also being controlled by turbine building pressure. As a result, maintenance of a positive pressure in the CRE with respect to the turbine building alone ensures adequate leakage control during the emergency mode of operation and is the appropriate measurement for TS Surveillance Requirement (SR) 3.7.9.6.
Question SCVB#4a The LAR states that new control room actions are required to restore the VNPAB within 30 minutes following alignment of residual heat removal to containment sump recirculation mode of operation. The LAR also states that if a loss-of-coolant accident occurs coincident with a loss of offsite power, the VNPAB system will be manually restarted to ensure that the primary auxiliary building vent stack is the source of the release associated with the emergency core cooling system (ECCS) leakage phase of the event. Provide the following additional information:
4a. Section 5.1.2 of regulatory guide I. 183 states that "assumptions regarding the occurrence and timing of a loss of offsite power should be selected with the objective of maximizing the postulated radiological consequences." Provide a discussion on how this guidance is factored in the AST analysis, and in the emergency operating procedures with respect to starting the VNPAB system.
NextEra Response As stated in Reference (3), "In general, the LOOP was used to limit equipment availability.
Where credited, safety related mitigating structures, systems, and components were assumed to operate consistent with single failure, design basis, emergency power, and other requirements."
For the loss-of-coolant accident (LOCA) AST analyses, loss of offsite power (LOOP) is assumed to occur concurrently with the LOCA event, maximizing the postulated radiological Page 4 of 6
consequences. The 30-minute requirement to restore VNPAB is specifically tied to alignment of residual heat removal (RHR) on recirculation, not on occurrence of the LOOP. Delaying the LOOP would only reduce the time the VNPAB exhaust fans are not operating, and thus, the analysis assuming a LOOP concurrent with a LOCA will remain bounding.
Emergency operating procedure (EOP) 1.3, Transfer to Containment Sump Recirculation - Low Head Injection, is being revised to require the start of the VNPAB within 30 minutes following the alignment of RHR to the containment sump recirculation mode of operation. For additional details on proposed EOP-1.3 changes, see letter dated July 24, 2009 (Reference 4), for NextEra's response to Question 1 from the Human Performance Branch.
Question SCVBWb
- 46. Your letter (NRC 2009-0045) dated April 17, 2009, provided proposed TS requirements for the VNPAB. This subject was briefly discussed with your staff in a phone call on June 23, 2009. The U.S. Nuclear Regulatory Commission staff's concern is that the suweillance requirement did not include a performance check of the VNPAB in terms of flow, pressure, etc. Please provide a discussion in how credit for VNPAB is taken in the AST dose analysis. Explain how the vent stack becomes the source of all releases during the ECCS leakage phase of the event by mere operation of the VNPAB fans, with no regard for any minimum amount of flow that the fans need to operate at.
NextEra Response The LOCA control room dose analysis assumes that the emergency core cooling system (ECCS) equipment leakage activity release pathway atmospheric dispersion factor (xJQ) to be at the location of the primary auxiliary building (PAB) vent stack, with no credit for dilution due to ventilation system airflow. Operation of the VNPAB exhaust system (i.e., one filter fan and one stack fan) assures this release point to be at the PAB vent stack. The PAB rooms with potential ECCS leakage sources are connected by ventilation ducts directly to the suction of the VNPAB fans. No minimum flow to the stack was assumed for the dose analysis.
Proposed TS SR 3.17.14.1 requires the VNPAB exhaust system to be operated for 215 minutes every 31 days, which allows problems to be identified and corrected. This surveillance approach is consistent with the approach taken at the Edwin I. Hatch Nuclear Plant for the turbine building ventilation exhaust system fans credited in the AST analysis, as approved in NRC letter dated August 28, 2008 (Reference 5).
During normal plant operation, one VNPAB filter fan and one stack fan are in operation, allowing for prompt problem identification and correction via the corrective action program, if required.
To further ensure the flow path to the PAB vent stack, NextEra currently trends stack flows in the plant process computer system (PPCS) and airflow readings are manually taken per plant procedure.
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Question SCVB#4c 4c. The LAR states that credit is not taken for the VNPAB air filters. However, performance readiness of the VNPAB fans depends on the filter loading conditions, Explain how operators verify that filfer plugging will not adversely affect the performance of the VNPAB fans.
NextEra Response Proposed TS SR 3.7.14.1 requires the VNPAB to be operated for ,I5 minutes every 31 days, which allows problems with filter plugging to be identified and corrected. Dioctyl phthalate (DOP) and freon filter performance testing are conducted, typically every 18 months, to determine the condition of the filters and to perform repairs as necessary. In addition, one VNPAB filter fan and one stack fan are normally in operation, and air flows are trended in PPCS which would provide early indication of a filter problem. Filter plugging would be identified and corrected via the corrective action program as a result of either performance of the SR, filter performance testing or normal operation of the system.
References
( 1 NRC letter to FPL Energy Point Beach, LLC, dated August 26, 2009, Point Beach Nuclear Plant, Units 1 and 2 - Request for Additional lnformation from Containment and Ventilation Branch Related to the Proposed Alternate Source Term Amendment (TAC Nos. ME0219 and ME0220) (ML092360535)
(2) FPL Energy Point Beach, LLC letter to NRC, dated December 8,2008, License Amendment Request 241, Alternative Source Term (ML083450683)
(3) NextEra Energy Point Beach, LLC letter to NRC, dated May 8, 2009, Supplement to License Amendment Request 241, Regulatory Guide I.I 83 Compliance Matrix (ML091320437)
(4) NextEra Energy Point Beach, LLC letter to NRC, dated July 24, 2009, License Amendment Request 241, Alternative Source Term, Response to Request for Additional lnformation (ML092080441)
(5) NRC Letter to Edwin I. Hatch Nuclear Plant dated August 28,2008, Edwin I. Hatch Nuclear Plant, Unit Nos. Iand 2, Issuance of Amendments Regarding Alternate Source Term (TAC Nos. MD2934 and MD2935) (ML081770071)
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ENCLOSURE 2 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 CREFS AND VNPAB BOUNDARY DRAVVINGS SUPPORTING THE NEXTERA RESPONSE TO QUESTION SCVB#l 2 pages follow
ENCLOSURE 3 NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS I AND 2 LICENSE AMENDMENT REQUEST 241 ALTERNATIVE SOURCE TERM RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION CREFS AND VNPAB AUGMENTED QUALITY EQUIPMENT LIST SUPPORTING THE NEXTERA RESPONSE TO QUESTION SCVB#l CREFS Augmented Qualitv Equipment List:
o Control room recirculation fans (W-I 391/92), motors and associated instrumentation and controls o Control room emergency fans (W-I 4AIB), motors and associated instrumentation and controls 0 Control room washroom exhaust fan (W-I 5) o CREFS filters (F-I6 and F-43) and associated housings and instrumentation o CREFS dampers and associated operators, instrumentation and controls o VNCR-4840AI9, control room recirculation fan backdraft dampers o VNCOMP-4849A, supply air to computer room damper o VNCOMP-48499, computer room return air damper o VNCR-4849C, control room recirculation fan outside air suction damper o VNCOMP-4849D, smokelheat exhaust fan return air control damper o VNCR-4849E, smokelheat exhaust fan return air control damper o VNCR-4849F, control room return air damper o VNCOMP-4849G, makeup air to offices damper o VNCSR-4850, control room recirculation fan suction damper Page 1 of 3
o VNCR-4851AIB, control room emergency fan suction dampers o VNCR-4851CID, control room emergency fan discharge control dampers o VNCR-4856AIB, control room emergency fan backdraft dampers o VNCR-6748, control room washroom exhaust fan damper e Housings (CREFS pressure boundary) for HX-91AIB, HX-92, HX-IOOAIB, and 2-77 and 2-78 e Ductwork and plenums highlighted on the CREFS boundary drawing in Enclosure 2 e Instrumentationtubing e Power and control cable for the above
@ Duct and equipment supports VNPAB Augmented Qualitv Equipment List:
e PAB exhaust stack fans (W-21A/B), motors and associated instrumentation and controls a PAB exhaust filter fans (W30AIB), motors and associated instrumentation and controls e VNPAB filters (F-23 and F-29), associated housings and instrumentation e VNPAB dampers and associated operators, instrumentation and controls o VNSSB-3246, service building exhaust fan discharge damper o VNSSB-3247, service building exhaust fan discharge damper o VNPAB-3248, PAB exhaust stack fan discharge control damper o VNPAB-3249, PAB exhaust stack fan discharge control damper o VNPAB-3256, PAB exhaust fan discharge control damper o VNPAB-3258AllA6, PAB exhaust filter inlet dampers o VNPAB-3258A2lA3lA41A5, PAB exhaust charcoal filter inlet dampers o VNPAB-3258BllB7lB8, PAB exhaust charcoal filter inlet dampers o VNPAB-3258B21B31B41B5IB6, PAB exhaust charcoal filter outlet dampers o VNPAB-3265, PAB exhaust filter fan discharge control damper Page 2 of 3
o VNPAB-3266, PAB exhaust filter fan discharge control damper e Ductwork and plenums highlighted on the VNPAB boundary drawing in Enclosure 2 e Instrumentationtubing
@ Power and Control cable for the above 0 Duct and Equipment supports Page 3 of 3