RS-13-127, First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design-Basis External Events (EA-12-049)

First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design-Basis External Events (EA-12-049)

ML13246A412
Person / Time
Site:	Peach Bottom
Issue date:	08/28/2013
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-049, RS-13-127
Download: ML13246A412 (17)

Text

1 Exelon Generation ~

Order No. EA-12-049 RS-13-127 August 28, 2013 u.s. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278

Subject:

First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)

References:

1. NRC Order Number EA-12-049, " Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012

2. NRC Interim Staff Guidance JLD-ISG-2012-01, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," Revision 0, dated August 29, 2012

3. NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide,"

Revision 0, dated August 2012

4. Exelon Generation Company, LLC's Initial Status Report in Response to March 12,2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated October 25, 2012

5. Exelon Generation Company, LLC Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated February 28, 2013 (RS-13-024)

6. NRC Order Number EA-12-050, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents," dated March 12,2012

7. NRC Order Number EA-13-109, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6,2013

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 August 28, 2013 Page 2 On March 12,2012, the Nuclear Regulatory Commission ("NRC" or "Commission") issued an order (Reference 1) to Exelon Generation Company, LLC (EGC). Reference 1 was immediately effective and directs EGC to develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities in the event of a beyond-design-basis external event. Specific requirements are outlined in of Reference 1.

Reference 1 required submission of an initial status report 60 days following issuance of the final interim staff guidance (Reference 2) and an overall integrated plan pursuant to Section IV, Condition C. Reference 2 endorses industry guidance document NEI 12-06, Revision 0 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 4 provided the EGC initial status report regarding mitigation strategies. Reference 5 provided the Peach Bottom Atomic Power Station, Units 2 and 3 overall integrated plan.

Reference 1 requires submission of a status report at six-month intervals following submittal of the overall integrated plan. Reference 3 provides direction regarding the content of the status reports. The purpose of this letter is to provide the first six-month status report pursuant to Section IV, Condition C.2, of Reference 1, that delineates progress made in implementing the requirements of Reference 1. The enclosed report provides an update of milestone accomplishments since the last status report, including any changes to the compliance method, schedule, or need for relief and the basis, if any.

As described in Reference 5, full implementation of NRC Order EA-12-049 required mitigation strategies is dependent upon implementation of reliable hardened containment venting capability established in accordance with NRC Order EA-12-050 (Reference 6). NRC Order EA-13-109 (Reference 7) issued by the NRC on June 6,2013, rescinded the requirements of Order EA-12-050 and established revised schedule timelines and implementation dates for reliable hardened containment vents capable of operation under severe accident conditions.

The revised schedule and implementation time line contained in Order EA-13-109 delays the ability to achieve full implementation of the mitigation strategy requirements of Order EA 049. This need for relaxation from the implementation requirements of Order EA-12-049 is described in Section 5 of the enclosed update report. The request for relaxation of the full implementation schedule requirements of Order EA-12-049 will be submitted separately.

This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David P. Helker at 610-765-5525.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 28th day of August 2013.

James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

u.s. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 August 28,2013 Page 3

Enclosure:

1. Peach Bottom Atomic Power Station, Units 2 and 3 First Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events cc:

Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Peach Bottom Atomic Power Station, Units 2 and 3 NRC Project Manager, NRR - Peach Bottom Atomic Power Station, Units 2 and 3 Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRC Mr. Robert J. Fretz, Jr, NRR/JLD/PMB, NRC Mr. Robert L. Dennig, NRR/DSS/SCVB, NRC Mr. Eric E. Bowman, NRR/DPRlPGCB, NRC Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources S. T. Gray, State of Maryland R. R. Janati, Commonwealth of Pennsylvania

Enclosure Peach BoHom Atomic Power Station, Units 2 and 3 First Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (13 pages)

Enclosure Peach Bottom Atomic Power Station Units 2 and 3 First Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events 1 Introduction Peach Bottom Atomic Power Station, Units 2 and 3 developed an Overall Integrated Plan (Reference 1 in Section 8), documenting the diverse and flexible strategies (FLEX), in response to Reference 2. This enclosure provides an update of milestone accomplishments since submittal of the Overall Integrated Plan, including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

2 Milestone Accomplishments None 3

Milestone Schedule Status The following provides an update to Attachment 2 of the Overall Integrated Plan. It provides the activity status of each item, and whether the expected completion date has changed. The dates are planning dates subject to change as design and implementation details are developed.

Target Revised Target Milestone Completion Activity Status Completion Date Date Submit 60 Day Status Report Oct 2012 Complete Submit Overall Integrated Plan Feb 2013 Complete Contract with RRC Complete Submit 6 Month Updates:

Update 1 Aug 2013 Complete with this submittal Update 2 Feb 2014 Not Started Update 3 Aug 2014 Not Started Update 4 Feb 2015 Not Started Page 1 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 Target Revised Target Milestone Completion Activity Status Completion Date Date Update 5 Aug 2015 Not Started Update 6 Feb 2016 Not Started Update 7 Aug 2016 Not Started Submit Completion Report Dec 2016 Not Started Perform Staffing Analysis May 2015 Not started Modifications:

Unit 2 Design Engineering May 2015 Started Unit 2 Implementation Outage Nov 2016 Not Started Unit 3 Design Engineering June 2014 Started Unit 3 Implementation Outage Oct 2015 Not Started Storage:

Storage Design Engineering Oct 2015 Not started Storage Implementation Oct 2015 Not started FLEX Equipment:

Procure On-Site Equipment Sept 2015 Started Develop Strategies with RRC Dec 2014 Started Procedures:

Create Site-Specific Procedures Sept 2015 Not started Validate Procedures (NEI-12.06, section Sept 2015 Not started 11.4.3)

Create Maintenance Procedures Sept 2015 Not started Training:

Page 2 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 Milestone Develop Training Plan Training Complete Unit 2 FLEX Implementation Unit 3 FLEX Implementation Full Site FLEX Implementation 4

Changes to Compliance Method General Integrated Plan Elements BWR-Change 1 Target Completion Date March 2015 Oct 2015 Oct 2016 Oct 2015 Oct 2016 Revised Target Activity Status Completion Date Not started Not started Not started Not started Not started Time Constraints-Action Item #14: Early Containment Venting. Early containment venting was to be initiated using the Torus Hardened Vent Line at approximately 4.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> into the event to prevent Torus temperature from exceeding 230 F.

Reason for change: Modification of the Torus Hardened Vent to allow venting at pressures below 30 psig have been delayed due to the Severe Accident Capable Vent (SACV) Order EA-13-109, scheduled for completion at Peach Bottom Unit 2 in Fall 2016 and Unit 3 in Fall 2017.

Maintain Core Cooling: Determine baseline coping capability with installed coping modifications not induding FLEX modifications. Utilizing methods described in Table 3-1 of NEI12-06:

Reactor Level Control: Venting of containment was to be initiated such that peak Suppression Pool temperature was to remain below the maximum allowed for RCIC operation, at 230 deg F.

Modifications to the Peach Bottom Torus Hardened Vent required to perform early venting have been delayed due to the Severe Accident Capable Vent (SACV) Order EA-13-109, scheduled for completion at Peach Bottom Unit 2 in Fall 2016 and Unit 3 in Fall 2017. Venting of containment using the Torus Hardened Vent could only now begin at a minimum containment pressure of 30 psig with a saturation temperature of the torus of at least 278 deg F. Conceptual Sketch and the discussion section for Safety Function Support show modifications to install FLEX 480VAC generator connections. The primary strategy is being revised to install a 480VAC portable generator connection in each unit's 135' elevation reactor building railroad access bay with cable supplying transfer switches to the E124 and E134 Load Centers. The alternate Page 3 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 strategy is being revised to install a 480VAC portable generator connection at each unit's Outage Power area behind the Reactor Building on the west wall with cable supplying the E324 and E334 Load Centers.

Existing cabling between the E124 and E324, and the E134 and the E334 Load Centers will be used to crosstie power from the FLEX generators. The 480VAC motor control centers required for FLEX will be powered from the E124, E324, E134 and E334 Load Centers. No new cables or modifications will be required to the motor control centers.

This change reduces the number of 480VAC Load Centers and Motor Control Centers to be powered by the FLEX generators. On Unit 2 the E224 and E424 480VAC Load Centers and the E224-R-B and E424-T-B 480VAC Motor Control Centers will not be powered. On Unit 3 the E234 480VAC Load Center and the E234-R-B and E234-T-B Motor Control Centers will not be powered. The Division 2 "B" RHR MO-2(3)-

25B valve for vessel injection and the MO-2(3)-39B and MO-2(3)-34B valves for Torus makeup will not have power and will be unavailable for operation from the Control Room. The Division 2 "B" RHR MO-2(3)-25B valve for vessel injection and the MO-2(3)-39B and MO-2(3)-34B valves for Torus makeup are not required for compliance with Order EA-12-049.

Maintain Containment: EPG/SAG Rev 3 guidance to perform early containment venting at approximately 4.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> into the event required modification to the existing Peach Bottom Torus Hardened Vent. These modifications have been delayed due to the Severe Accident Capable Vent (SACV) Order EA-13-109, scheduled for completion at Peach Bottom Unit 2 in Fall 2016 and Unit 3 in Fall 2017.

Change 2 Key Containment Parameters: Torus Wide Range Level Instruments LR/TR-8(9)123A is added to the Key Containment Parameters list of instrumentation.

Change 3 Conceptual Sketch and the SFP Makeup discussion section for the Maintain Spent Fuel Pool Cooling show water supply modifications to the Spent Fuel Pool by installing additional manual valves and hose connections downstream of HV-(3)-4457A and HV-2(3)-4457B. This is being revised to a single hose connection upstream of the HV-2(3)-4457A and HV-2(3)-4457B on 165' Reactor Building with sections of fire hose then routed to the 234' elevation of the Refuel Floor. Hoses will then be used to makeup to the Spent Fuel Pool or provide spray capability to the Spent Fuel Pool. The new hose connections will be installed on seismically rated piping.

Change 4 Conceptual Sketch and the discussion section for Safety Function Support show modifications to install FLEX 480VAC generator connections. The primary strategy is being revised to install a 480VAC portable generator connection in each unit's 135' elevation reactor building railroad access bay with cable supplying transfer switches to the E124 and E134 Load Centers. The alternate Page 4 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 strategy is being revised to install a 480VAC portable generator connection at each unit's Outage Power area behind the Reactor Building on the west wall with cable supplying the E324 and E334 Load Centers.

Existing cabling between the E124 and E324, and the E134 and the E334 Load Centers will be used to crosstie power from the FLEX generators. The 480VAC motor control centers required for FLEX will be powered from the E124, E324, E134 and E334 Load Centers. No new cables or modifications will be required to the motor control centers.

This change reduces the number of 480VAC Load Centers and Motor Control Centers to be powered by the FLEX generators. On Unit 2 the E224 and E424480VAC Load Centers and the E224-R-B and E424-T-B 480VAC Motor Control Centers will not be powered. On Unit 3 the E234 480VAC Load Center and the E234-R-B and E234-T-B Motor Control Centers will not be powered. The Division 2 "B" RHR MO-2(3)-

25B valve for vessel injection and the MO-2(3)-39B and MO-2(3)-34B valves for Torus makeup will not have power and will be unavailable for operation from the Control Room. The Division 2 "B" RHR MO-2(3)-25B valve for vessel injection and the MO-2(3)-39B and MO-2(3)-34B valves for Torus makeup are not required for compliance with Order EA-12-049.

The OAV030 Control Room Emergency Vent Supply Fan A, the OAV034 Emergency Switchgear and Battery Room Vent Supply Fan A and the OAV036 Battery Room Exhaust Fan A are powered from the E324-T-B Motor Control Center and will be available for operation.

5 Need for ReliefIRelaxation and Basis for the ReliefIRelaxation Relief /Relaxation is required due to the delay in the modifications to the Torus Hardened Vent due to the Severe Accident Capable Vent (SACV) Order EA-13-109 (Reference 3).

This section provides a summary of needed relief/relaxation only. The specific details will be submitted in a separate document at a later date.

NRC Order EA-12-049 requires implementation of Mitigation Strategies to include procedures, guidance, training, and acquisition, staging, or installing of equipment needed for the strategies. Reference 1 provided the Peach Bottom Atomic Power Station response to NRC Order EA-12-049. The cover letter identifies that delays in implementing the Hardened Containment Vent System as required by NRC order EA-12-050 (Reference 4) will also affect implementation of the Mitigation Strategies Order EA-12-049 actions.

The Reference 1 enclosure describes the Peach Bottom Atomic Power Station Mitigation Strategies that is based on venting the containment using the Hardened Containment Vent System. It also describes that a modification to install a Hardened Containment Vent System (HCVS) is required.

Thus, the Peach Bottom Atomic Power Station NRC Order EA-12-049 response provided in Reference 1 was premised on installation and use of a Hardened Containment Vent System as required by NRC Order Page 5 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 EA-12-0S0. Upon issuance of NRC Order EA-13-109, the NRC staff changed technical and schedule requirements applicable to the Hardened Containment Vent System and rescinded the requirements of NRC Order EA-12-0S0.

As a result, full compliance to the Mitigation Strategies required by NRC Order EA-12-049 and described in Reference 1 for Peach Bottom Atomic Power Station Units 2 and 3 will not be achieved until compliance to NRC Order EA-13-109 is achieved. Relief/relaxation from the NRC Order 12-049 IV.A.2 requirements is required.

Peach Bottom Atomic Power Station will be in compliance with the aspects of the Reference 1 Unit 2 and Unit 3 Mitigation Strategies that do not rely upon a Hardened Containment Vent System unless otherwise described.

6 Open Items from Overall Integrated Plan and Draft Safety Evaluation The following tables provide a summary of the open items documented in the Overall Integrated Plan or the Draft Safety Evaluation (SE) and the status of each item.

Section Reference Overall Integrated Plan Open Item Status Multiple Sections Item 1) Transportation routes will be Started developed from the equipment storage area to the FLEX staging areas. An administrative program will be developed to ensure pathways remain clear or compensatory actions will be implemented to ensure all strategies can be deployed during all modes of operation. The location of the storage areas, identification of the travel paths and creation of the administrative program are open items.

Programmatic Controls (p. 7)

Item 2) An administrative program for FLEX Not started to establish responsibilities, testing and maintenance requirements will be implemented.

Describe Training Plan (p. 8)

Item 3) Training materials for FLEX will be Not started developed for all station staff involved in implementing FLEX strategies.

Page 6 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 Maintain Spent Fuel pool Item 4) Complete an evaluation of the spent Not started Cooling (p. 30) fuel pool area for steam and condensation to determine vent path strategy requirements.

Safety Function Support (p.

Item 5) ROC room temperature analysis is Started

38) still in progress.

Safety Function Support Item 6) Evaluate the habitability of the Main Not started (p.38)

Control Room and develop a strategy to maintain habitability.

Safety Function Support (p.

Item 7) Develop a procedure to prop open Not started

38) battery room doors and utilize portable fans or utilize installed room supply and exhaust fans upon energizing the battery chargers to prevent a buildup of hydrogen in the battery rooms.

Sequence of Events (p. 4)

Item 8) Timeline walk through will be Not started completed for the FLEX generator installations when the detailed design and site strategy is finalized. The final timeline will be validated once the detailed designs are developed. The results will be provided in a future 6 month update.

Sequence of Events (pA)

Item 9) Timeline walk through will be Not started completed for the FLEX pump installations when the detailed design and site strategy is finalized. The final time line will be validated once the detailed deSigns are developed.

The results will be provided in a future 6 month update.

Sequence of Events (p. 5)

Item 10) Additional analysis will be Not started performed during detailed design development to ensure Suppression Pool temperature will support RCIC operation, in accordance with approved BWROG analysis, throughout the event.

Page 7 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 Sequence of Events (p. 5)

Item 11) Analysis of deviations between Completed.

Exelon's engineering analyses and the included in analyses contained in BWROG Document this six month update NEDC-33771P, "GEH Evaluation of FLEX Implementation Guidelines and documentation of results on Att. lB, "NSSS Significant Reference Analysis Deviation Table." Planned to be completed and submitted with August 2013 Six Month Update.

Draft Safety Evaluation Open Item Status N/A N/A 7 Potential Draft Safety Evaluation Impacts There are no potential impacts to the Draft Safety Evaluation identified at this time.

8 References The following references support the updates to the Overall Integrated Plan described in this enclosure.

1.

Peach Bottom Atomic Power Station Units 2 and 3, Overall Integrated Plan in Response to March 12,2012 Commission Order Modifying licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated February 28, 2013.

2.

NRC Order Number EA-12-049, "Order Modifying licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012.

3.

NRC Order Number EA-13-109, "Order Modifying licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013.

4.

NRC Order Number EA-12-050, "Order Modifying licenses with Regard to Reliable Hardened Containment Vents," dated March 12, 2012 Page 8 of 13

Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 2013 9 Attachments

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PBAPS Primary and Alternate Power Requirements Electrical Schematic

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FLEX Simplified Design Mechanical Schematic

3.

Peach Bottom Atomic Power Station FLEX Integrated Plan Analyses Reconciliation to NEDC-33771P, Rev 1 Page 9 of 13

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Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28, 2013 Peach Bottom Atomic Power Station FLEX Integrated Plan Analyses Reconciliation to NEDC-33771P, Rev 1 (Attachment 1B in the Overall Integrated Plan Report)

NOTE: NEDC-33771P, Rev 1, Appendices Band D (BWR/4 Mark I with RCiC (No Venting, Suction From Suppression Pool, and Venting Starting at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, Suction From CST)) are most similar to the Peach Bottom Atomic Power Station FLEX Plan strategy for maintaining Containment Integrity. Notable differences between the input parameters used in the Peach Bottom Atomic Power Station FLEX analyses and the NEDC-33771P, Rev 1, analyses are noted below in the Gap and Discussion column.

NEDC-Peach Bottom Item Parameter of Interest 33771P Analyses Applied Design Gap and Discussion Value (Page Value Value Reference)

Input Parameter Values 1

Core Thermal Power 17 3517 MWT 100%

N/A 2

Reactor Dome Pressure 17 1050 psia N/A 3

Initial RPV Water Level above 17 562.5 inches N/A vessel zero MAAP model configured with Recirc pump 4

Primary system Leakage 17 42gpm N/A leakage 18 gpm/pump, 5 gpm unidentified leakage and 1 gpm identified leakage 5

RPV Depressurization Time 17 20 minutes N/A 6

RPV Depressurization Rate 17 80 F / hour N/A 7

RPV Maintained Pressure 17 200 psig N/A 8

Initial Wetwell Airspace 17 145 F N/A Temperature 9

Initial Wetwell Pressure 17 15.2 psia N/A 10 Suppression Pool Level 17 14.5 feet N/A Page 12 of 13

Item 11 12 13 14 15 Peach Bottom Atomic Power Station, Units 2 and 3 First Six Month Status Report for the Implementation of FLEX August 28,2013 NEDC-Peach Bottom Parameter of Interest 33771P Analyses Applied Design Gap and Discussion Value (Page Value Reference)

Value Initial Suppression Pool 17 95 F N/A Temperature Drywell Free Volume 17 116,882.37 fe N/A Start of Venting 17 4.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> N/A MAAP Containment Venting starting when torus temperature exceeds 200 F Venting Flow Coefficient 17 0.75 N/A Venting Pipe Size 17 16 inches N/A Resultant Parameter Values Maximum Suppression Pool Temperature (Venting, Torus 34 221 Fat 11.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 281°F Suction)

The differences identified between the SHEX and MAAP analyses are due to the time in Maximum WetWell which containment venting was initiated.

Temperature (Venting, Torus 34 241 Fat 13.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> 281°F Analyses of the containment pressures and Suction) temperature prior to initiation of the venting Maximum Wetwell Pressure 34 25.0 psi a at 4.7 56psig action are approximately equal. The time for (Venting, Torus Suction) hours containment venting initiation in the MAAP Maximum Drywell analysis is based on Torus temperature Temperature (Venting, Torus 34 256 F at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 281°F exceeding 200 deg F.

Suction)

Maximum Drywell Pressure 34 24.9 psia at 4.7 56psig (Venting, Torus Suction) hours Page 13 of 13