Text

Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses Re Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order EA-12-049)
	ML14063A221
Person / Time
Site:	Three Mile Island
Issue date:	02/28/2014
From:	David Helker; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	EA-12-049, RS-14-016, TMI-14-006
	Download: ML14063A221 (50)
	v • d • e

1 Exelon Generation Order No. EA-12-049 RS-14-016 TMI-14-006 February 28, 2014 u.s. Nuclear Regulatory Commission ATTN : Document Control Desk Washington , DC 20555-0001 Three Mile Island Nuclear Station , Unit 1 Renewed Facility Operating License No . DPR-50 NRC Docket No. 50-289

Subject:

Second 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-13-026)

6. Exelon Generation Company, LLC 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 049), dated August 28, 2013 (RS-13-131)

7. NRC letter to Exelon Generation Company, LLC , Three Mile Island Nuclear Station, Unit 1 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies) (TAC Nos. MF0803) , dated December 17, 2013

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 28, 2014 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 Three Mile Island Nuclear Station, Unit 1 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. Reference 6 provides the first six-month status report pursuant to Section IV, Condition C.2, of Reference 1 for Three Mile Island Nuclear Station, Unit 1. The purpose of this letter is to provide the second 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. The enclosed report also addresses the NRC Interim Staff Evaluation Open and Confirmatory Items contained in Reference 7.

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 February 2014.

Respectfully submitted, David P. Helker Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

1. Three Mile Island Nuclear Station, Unit 1 Second 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

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 28, 2014 Page 3 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Three Mile Island Nuclear Station, Unit 1 NRC Project Manager, NRR - Three Mile Island Nuclear Station , Unit 1 Ms. Jessica A. Kratchman , NRR/JLD/PMB, NRC Mr. Jack R. Davis, NRR/DPR/MSD, NRC Mr. Eric E. Bowman , NRR/DPR/MSD, NRC Mr. Jeremy S. Bowen , NRR/DPR/MSD/MSPB, NRC Mr. Robert L. Dennig, NRR/DSS/SCVB, NRC Mr. Peter Bamford, NRR/DPR/MSD/MSPB, NRC Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources Chairman , Board of County Comm issioners of Dauphin County, PA Chairman , Board of Supervisors of Londonderry Township, PA R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection , Bureau of Radiation Protection

Enclosure Three Mile Island Nuclear Station, Unit 1 Second 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 (46 pages)

Three Mile Island Station, Unit 1 Second 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 Three Mile Island Nuclear Station, Unit 1 (TMI) 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 last status report (August 2013), including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

2 Milestone Accomplishments The following milestone(s) have been completed since July 30, 2013 and are current as of February 1, 2014.

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.

The revised milestone target completion dates do not impact the order implementation date.

Orig inal Target Activity Status Completion Date Submit 60 Day Status Report Complete Submit Overall Integrated Complete Implementation Plan Contract with RRC Complete 6 Month Updates Update 1 Aug., 2013 Complete Update 2 Feb., 2014 Complete with this submittal Update 3 Aug. , 2014 Not Started Update 4 Feb. , 2015 Not Started Page 1 of 46

Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 Original Target Activity Status Completion Date Update 5 Aug ., 2015 Not Started Update 6 Feb. , 2016 Not Started Modification Development Oct 2014 Phase 1 modifications (1) RCP Seal Upgrade (1) Started (2) Condensate piping supports (2) Started Oct 2014 Phase 2 modifications (1) FLEX Electrical Power Supply (1) Started (2) FLEX RCS & SFP Makeup (2) Started (3) FLEX Feedwater System (3) Started (4) FLEX Storage Facility (4) Started (5) Turbine Bldg Structural (5) Started (6) FLEX fuel oil supply (6) Started (7) Spent Fuel Pool Level (7) Started (8) Communications modification (8) Not Started (9) Main Generator Purge (9) Not Started (10) Reactor Building Vent (10) Not Started (11 ) Satellite phone storage (11) Complete Oct 2014 Phase 3 modifications Not Started Modification Implementation Nov 2015 Phase 1 modifications (1) RCP Seal Upgrade Not Started (2) Condensate pipinQ supports Nov 2015 Phase 2 modifications (1) FLEX Electrical Power Supply Not Started (2) FLEX RCS & SFP Makeup (3) FLEX Feedwater System (4) FLEX Storage Facility (5) Turbine Bldg Structural (6) FLEX fuel oil supply (7) Spent Fuel Pool Level (8) Communications modification (9) Main Generator Purge (10) Reactor Building Vent (11) Satellite phone storage Nov 20 15 Phase 3 modifications Not Started Page 2 of 46

Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 Original Target Activity Status Completion Date Procedure development Jun 2015

Create Site-Specific Procedures Started Jul 20 15

Validate Procedures (NEI 12-06, Started Sect. 11.4.3)

Jun 2015

Create Maintenance Procedures Started Jul 2015 Staffing analysis Started Nov 2015 Storage Plan Started Nov 2015 FLEX equipment acquisition Started Nov 2015 Training Started Jul 20 15 Regional Response Center Operational Started Nov 2015 Unit 1 Implementation date Page 3 of 46

Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 4 Changes to Compliance Method The following significant changes have been made to the FLEX conceptual design:

(1) FLEX Diesel Generator and Fuel Oil Supply (Reference Attachment 2A) o FLEX Diesel Generators FX-Y-1A & Band FX-T-2 will be located at the south end of the Turbine Bldg o Skid mounted fuel tanks will be used for the initial supply. FX-T-2 will normally be empty and only used for floods. Fuel Supply from DF-T-1 will directly fill FX-T-2, or FX-Y-1A or B skid mounted tanks. New pumps (FX-P-5A & B) will be used to transfer fuel from FX-T-2 to the skid mounted fuel tanks.

(2) FLEX Electrical Distribution (Reference Attachment 2B) o A 480V distribution panel and a transfer switch replace the FLEX 480V MCC o Temporary cable will be used for power to FX-P-2A & B o The temporary power feed to RB H&V MCC is no longer required o 120VAC regulated panel ATC will be modified to provide power to FLEX temporary ventilation (3) FLEX Feedwater System (Reference Attachment 2C) o Capacity of FX-P-2A & B was increased, and series operation with a portable diesel driven pump (FX-P-3 or 4) was eliminated.

(4) FLEX RCS and SFP Makeup System (Reference Attachment 2D) o Added flow path for core cooling via Spent Fuel Pool gravity drain o Added RB vent path The following significant changes have been made to the FLEX Sequence of Events and Timelines (Reference Attachment 1A (Earthquake or Tornado Event Timeline) , Attachment 1B (External Flood Event Timeline) and Attachment 1C (Extreme Cold , Snow & Ice event timeline).

o Previously only the earthquake/tornado event SOE was described. The SOE for flood or extreme cold , snow & ice events in Attachment 1B & 1C are new.

o Description of operator interaction with SBO diesel was split into two items to show action being initiated and the recognition that the SBO diesel as unavailable as two separate events. (Confirmatory Item 3.2.1.6.0) o Actions (item 14 in AUG 13 update) to move a diesel driven pump into the Turbine Bldg have been removed o New actions (Attachment 1A 16 & 17) describe contingencies to deal with condensate inventory loss or internal flooding hazard o Attachment 1A items 40 & 41 , describe when backup feedwater is available << 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months ) and final RCS & OTSG conditions .

5 Need for Relief/Relaxation and Basis for the Relief/Relaxation TMI Unit 1 expects to comply with the Order implementation date and no relief/relaxation is required at this time.

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Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 6 Open Items from Overall Integrated Plan and Interim Staff Evaluation Section Reference Overall Integrated Plan Open Item Status (Refer to OIP Update (Refer to OIP Update from Aug 2013) (As of February 1, 2014) from Aug 2013)

Key Site Routes from the storage locations have not Closed to "ISE Open &

Assumptions (pg 3) yet been assessed for hazard impact. This Confirmatory Item" NO.6.

and Strategy will be completed and communicated in a Deployment (pg 5) future 6-month update following evaluation.

Sequence of Events The times to complete actions in the Events SOE Timelines are included in (pg 4) Timeline are based on operating judgment, Attachment 1A, 1Band 1C.

the conceptual designs, and the current Closed to "ISE Open &

supporting analyses. The final timeline will be Confirmatory Item" No. 22 .

validated once detailed designs are completed, procedures are developed, and the results will be provided in a futu re six (6) month update.

Maintain RCS Core cooling and RCS inventory analysis is Complete Inventory (pg 17) not complete at this time. Completion of this analysis is an open item . Closure of this item will be documented in a future six (6) month update.

Maintain Core ECR 13-00071 FLEX Feedwater System is Closed to "Milestone Schedule" Cooling and Heat not finalized . Changes will be provided in a tracking in Section 3 Removal (pg 10) 6-month update.

Maintain Core ECR 13-00074 FLEX Storage Building is not Closed to "Milestone Schedule" Cooling and Heat finalized. Changes will be provided in a six tracking in Section 3 Removal (pg 10) (6) month update.

Maintain RCS ECR 13-00099 RC-P Low Leakage Seals is Closed to "Milestone Schedule" Inventory (pg 16) not finalized . Changes will be provided in a tracking in Section 3 six (6) month update.

New ECR , no ECR 13-00078 Turbine Building Structural Closed to "Milestone Schedule" reference . Modifications is not finalized. Changes will be tracking in Section 3 provided in a six (6) month update.

New ECR, no ECR 13-00164 FLEX Fuel Oil and Fire Closed to "Milestone Schedule" reference . Protection is not finalized. Changes will be tracking in Section 3 provided in a six (6) month update.

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Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 Section Reference Overall Integrated Plan Open Item Status (Refer to OIP Update (Refer to OIP Update from Aug 2013) (As of February 1, 2014) from Aug 2013)

Maintain Core A portable refueling vehicle with a large Closed to "ISE Open &

Cooling and Heat diesel oil bladder will be available on site to Confirmatory Item" No. 29.

Removal (pg 14) support refilling our portable equipment diesel tanks. An additional means (river makeup is available) of delivering condensate may also be developed; details to be provided in a future 6-month update.

Maintain Spent Fuel Spent Fuel Pool - These strategies utilize a Closed to "ISE Open &

Pool Cooling (pg vent path for steam. The effects of this steam Confirmatory Item" No. 30

29) on other systems and equipment will be evaluated, and the results will be provided in a future six month update.

Maintain Spent Fuel ECR 13-00084 for Spent Fuel Pool Closed to "Milestone Schedule" Pool Cooling (pg Instrumentation. This ECR is an open item. tracking in Section 3

30) Closure of this item will be documented in a future six (6) month update.

Maintain RCS ECR 13-00072, FLEX RCS Make-up System Closed to "Milestone Schedule" Inventory (pg 18) - This ECR is an open item. Closure of this tracking in Section 3 item will be documented in a future six (6) month update.

Maintain RCS A plan will be developed to re-supply borated Complete Inventory (pg 22) water to the BWST or SF pool.

On site storage will provide borated water for greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months in the limiting case. RRC will provide capability to prepare and deliver borated water if needed.

Maintain RCS TM-FLEX-001, Core Cooling Analysis, Complete Inventory (pg 17) DRAFT, is not approved. The results of this analysis will be integrated into a future 6-month update.

Maintain TM-FLEX-002, RB Pressure Analysis, Rev 0 Complete Containment (pg (Reference 4), results show that Reactor

26) Building pressure will remain below design pressure without any active means of RB cooling for any event where the OTSG is available to remove core heat.

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Three Mile Island Nuclear Station, Unit 1 Second Six Month Status Report for the Implementation of FLEX, February 28, 2014 Section Reference Overall Integrated Plan Open Item Status (Refer to OIP Update (Refer to OIP Update from Aug 2013) (As of February 1, 2014) from Aug 2013)

Safety Function ECR 13-00070 FLEX Electrical Power Closed to "Milestone Schedule" Support (pg 37) Supply. This ECR is an open item. Closure tracking in Section 3 of this item will be documented in a future six (6) month update.

Safety Function Within the Main Control Room, habitability Closed to "ISE Open &

Support (pg 37) conditions will be evaluated and a strategy Confirmatory Item" No. 34.

will be developed to maintain Main Control Room habitability. The strategy will be provided in a future six (6) month update.

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Interim Staff Evaluation Open Item or Confirmatory Items Item NRC ref Description Status

no.

FEB 2014 UPDATE 1 3.2.1.1.B Provide the analysis supporting the licensee's mitigation WCAP 17792-P has been issued by PWROG.

strategy (WCAP-17792-P) for NRC staff review, identify TMI Plan is described in Attachment 3 of this update.

the specific calculation(s) in WCAP-17792 considered applicable to demonstrating the feasibility of the proposed COMPLETE strategy, and justify the applicability of the calculation(s) relied upon in WCAP-17792 to TMI-1 .

2 3.2.1.1.C As applicable, provide additional analyses for core TMI Plan is described in Attachment 3 of this update.

cooling, RCS makeup, and shutdown margin that are COMPLETE relied upon, but not included in WCAP-17792-P.

3 3.2.4.7.A The licensee appears to use a probabilistic approach to TMI Plan is described in Attachment 3 of this update.

reach a conclusion that at least one of the three tanks COMPLETE depended on for RCS makeup will survive an ELAP event. NE112-06 guidance does not include this option.

Provide further justification for this alternate approach.

4 3.2.4.8.B On page 37 of the Integrated Plan, the licensee states TMI Plan is described in Attachment 3 of this update.

that two (2) diesel generators along with Fuel Tanks will COMPLETE be pre-staged in a protected enclosure on the 322' elevation of the Turbine Building. Provide justification addressing the flexibility of this alternate approach to mitigate BDBEEs.

5 3.1 .1.1.A The licensee stated that protection of associated portable The Unit 2 screen house will be modified to be used as the FLEX equipment from external hazards would be provided in equipment storage facility. The U2 screen house is a tornado structures that will be constructed to meet the hardened seismic Class I structure with the floor at 312' elevation.

requirements of NEI 12-06 Section 11 . However the The structure will be modified to provide a new access for the FLEX licensee did not specify the type of configuration, how truck and equipment trailers. The new access will provide tornado FLEX equipment would be secured, or how stored protection and remain functional after a tornado event. The equipment and structures would be protected from all equipment stored in the building will be evaluated and secured as external hazards. needed to ensure FLEX equipment is not damaged during a seismic event. The elevation is sufficient to prevent equipment damage during an external flood event. COMPLETE Page 8 of 46

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. FEB 2014 UPDATE 6 3.1 .1.2.A The licensee did not specifically address deployment (1) The potential for earthquake induced liquefaction has been considerations with respect to the deployment of FLEX evaluated. Deployment of TMI1 FLEX equipment will not be adversely impacted. (Reference 990-2179 "Assessment of equipment through areas subject to liquefaction, routing earthquake-induced liquefaction potential and associated ground only through seismically robust buildings, power required failure hazards for Three Mile Island Unit 1", Geomatrix to deploy or move equipment, and protection of the Consultants.

means to move equipment. (2) The evaluation of access paths through non-seismic structures is in progress. (AUG 2014 Update)

(3) A vehicle stored in the FLEX storage facility will be used to deploy or move FLEX equipment. No additional power is required.

7 3.1.1.3.A The licensee did not address the determination of AUG 2014 Update necessary instrument local readings per consideration 1 of NE112-06 Section 5.3.2 , to support the implementation of the mitigating strategies in the event that seismically qualified electrical equipment is affected by a BDBEE.

8 3.1 .1.4.A The licensee did not identify the local assembly area or FEB 2015 Update describe the methods to be used to deliver the equipment to the site for all hazards. In the audit process the licensee stated that the TMI RRC playbook will be made available when approved to address this.

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FEB 2014 UPDATE 9 3.1.2.2 .A The licensee did (not) specifically address considerations All FLEX actions for an external flood event (1) are performed prior to 2 , 3,4, 5,8, and 9 of NE112-06 Section 6.2.3.2 regarding the ELAP event based on flood warning time, (2) are performed at deployment of FLEX equipment. elevations above the PMF peak water level or (3) were evaluated as follows to address access and deployment concerns.

After the water recedes below site grade , a portable diesel driven pump (FX-P-3 or 4) will be moved from the FLEX Storage Facility to the ramp next to the river located west of the NOB. The pump and RRC supplied water filtration equipment will be used to provide a continuous condensate supply to CO-T1B. Debris removal may be required on the road or the river ramp. There is a minimum of five days to reliably accomplish this task with RRC support.

COMPLETE 10 3.1.3 .2.A The licensee did not address considerations 2-5 of NEI (2) If the capability to utilize the ultimate heat sink (Susquehanna 12-06 Section 7.3.2 regarding loss of access to the River) is affected by hurricane or tornado, an alternate means to ultimate heat sink, the need to remove debris, a means to obtain river water has been developed. A portable diesel driven move equipment that is protected , and the ability to pump (FX-P-3 or 4) will be moved from the Flex Storage Facility restock supplies. (FSF) to the ramp next to the river located west of the NOB. The pump (RRC supplied water filtration equipment will be used after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ) will be used to provide a continuous condensate supply to CO-T1 B or the hotwell.

(3 & 4) Debris removal may be required on the road or the river ramp. The equipment used to move the FLEX equipment and for debris removal will be stored in the FSF for protection during the event.

(5) No event specific proactive action is necessary for mitigation of tornado or high wind events.

COMPLETE Page 10 of 46

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FEB 2014 UPDATE 11 3.1.S.3.A The licensee provided no information regarding the heat A plan to provide portable ventilation for areas where natural up of various rooms and enclosures in the Integrated circulation may be insufficient and key FLEX equipment performance Plan, and there was no discussion of the potential effects may be adversely affected by abnormally high ambient temperature of high temperatures at the location where portable (or is being prepared.

permanently installed FLEX) equipment would actually AUG 2014 UPDATE operate in the event of high temperatures in these plant locations.

12 3.2 .1.A The licensee needs to confirm that the transition to the If the transition to the backup feedwater system is planned, there will backup feedwater system will occur without a significant be no interruption of feedwater. The primary and backup systems interruption of feedwater to the steam generators. can be operated in parallel.

If the transition to the backup feedwater system is not planned (i.e., a failure of the primary feedwater source), then the impact on core cooling should be insignificant. Before the plant reaches the conditions where the backup feedwater capability is enabled, the backup feedwater pumps (FX-P-2A & B) will be configured and all valves will be lined up, leaving one valve to each OT8G to control backup FW flow. If EF-P-1 fails, FX-P-2A or B will be started and flow can be re-established within minutes. OT8G water level will be maintained high enough such that an interruption for several minutes would have only a minor effect on Re8 temperature , and core cooling would be maintained.

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FEB 2014 UPDATE 13 3.2.1.B The licensee needs to provide adequate technical basis Prior analysis to determine the RCS pressure when CFT N2 injection for concluding that nitrogen injection will not occur from could occur established that pressure at 202 psig (

Reference:

C-the core flood tanks. 1101-213-5450-002). If a very conservative approach to temperature is taken, and the CFT is assumed to immediately rise to the RB temperature 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months into the event (i.e . 230 F) , the RCS pressure where N2 injection could occur rise to 256 psig.

The TMI strategy includes a slow RCS cooldown and depressurization to the point where RCS pressure is stabilized at 400 psig. Therefore , there is large margin to the point where CF N2 injection could occur In addition , power will be restored to the CF isolation valves early in the event (within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ) such that the control room would have the capability to remotely close the valves if needed. Once a pressurizer steam bubble is established , the core flood isolation valves will be closed.

COMPLETE.

14 3.2.1.1.A The licensee needs to confirm that analysis and See Attachment 3 of this document conclusions based on simulations with the MAAP4 code COMPLETE.

are not relied upon for demonstrating adequate core cooling , RCS makeup, or shutdown margin for TMI-1 .

15 3.2.1.1.D The licensee did not provide information confirming that The TMI strategy and supporting technical analysis do not rely upon reliance on the RELAP5/MOD2-B&W code in the ELAP operation in or recovery from boiler condenser cooling. Single phase analysis for Babcock and Wilcox plants is limited to the sub-cooled conditions are maintained at all times.

flow conditions before boiler-condenser cooling initiates.

COMPLETE .

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FEB 2014 UPDATE 16 3.2.1.2.A The 1A and 1B ES motor control center (MCG) will be See Attachment 3 of this document.

energized using the FLEX diesel generators as described COMPLETE in Safety Functions Support section and the FLEX RCS makeup pump will be started within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The analysis to confirm the timeline is not yet complete.

17 3.2 .1.2.B Information should be provided to justify that the The N-9000 seal design and testing demonstrates that the seals will procedures are effective to keep the RCS temperatures not be degraded if water temperature at the seal is maintained below within the limits of the seal design temperatures, and 560F. In the event of an ELAP, the seal temperature will rise to RCS address the adequacy of the seal leakage rate (2 gallons cold leg temperature after 10 or more minutes. Automatic and per minute (gpm)/seal) used in the ELAP analysis. manual control will maintain OTSG pressure at approximately 1000 psig . Therefore, OTSG temperature will be approx. 547F and cold leg temperature will be approximately 550F. The RCP seal temperature will remain below 560F throughout the event.

The initial RCS loss rate due to seal leakage and controlled bleed off flow will be less 2.6 GPMI RCP . This value is based on an RCS pressure at 2150 psig. After an ELAP RCS pressure will be lower and losses will be less. Once CBO flow is isolated the total loss rate per RCP will be much less than 1 GPM . As described in Attachment 3, a total RCS loss rate of 20 GPM was used in the MAAP analysis, and a rate of 11 GPM was used to apply the WCAP 17792 analysis product.

OPEN - Pending delivery of supporting Flowserve documentation to NRC byPWROG 18 3.2.1 .2.C For plants such as TMI-1 that credit low leakage seals to See item #17 maintain the initial maximum leakage rate of 2 gpm/seal COMPLETE.

for the ELAP analyses of the RCS response, a discussion of the information (including seal leakage testing data) should be provided to justify the use of 2 gpm/seal in the ELAP analysis.

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FEB 2014 UPDATE 19 3.2.1 .2.D Address the acceptability of using the Flowserve N-9000 See item #17 RCP [Reactor coolant Pump] seals with the abeyance COMPLETE.

seal in the Westinghouse RCPs . The RCP seal leakages rates for use in the ELAP analysis should be provided with acceptable justification.

20 3.2.1.4.A The licensee did not provide any further description of For RCS core decay heat generation rates, earthquake or tornado specific initial key plant parameters specified in NE112- analysis is based upon (1) reactor operation for at least 100 days at 06, Sections 3.2 .1.2 and 3.2.1.3 except the assumption 100% power, (2) the reactor has been shut down for at least 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months regarding SSC's, and the items from the Sequence of for the initial conditions where OTSG steam pressure is insufficient to Events (SOE) Attachment 1A. The licensee did not drive the EFW pump, or (3) the reactor has been shutdown at least provide the initial conditions used in the RCS and SFP 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months before the OTSG is unavailable, and gravity drain core calculations used in ER-TM-TSC-0016. cooling methods are required. For flood event analysis, if the reactor had been at 100% power when the flood condition was recognized ,

then the reactor will be shut down for at least 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months when the ELAP occurs. For flood event analysis, if the reactor had been in refueling conditions when the flood condition was recognized, then the reactor will be shut down for at least 96 hours0.00111 days 0.0267 hours 1.587302e-4 weeks 3.6528e-5 months when the ELAP occurs.

For the spent fuel pool heat generation rates, (1) If there is a full load of fuel in the core, then the spent fuel pool heat load is based upon the long term fuel load plus one third of core 20 days after reactor shutdown . (2) At any other time, the design basis (Reference UFSAR section 9.4.1) spent fuel pool heat load is assumed (i.e., a full core offload plus one third of a core 36 days after reactor shutdown plus the long term heat load).

COMPLETE .

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FEB 2014 UPDATE 21 3.2 .1.5.A The licensee's evaluation of the FLEX strategy may The instruments requ ired to support key actions for FLEX are :

identify additional parameters that are needed to support RCS Pressure key actions identified in the plant procedures/guidance or RCS water level (pressurizer level or "RCS drain down" level to indicate imminent or actual core damage. Differences as applicable) will be provided in a future 6-month update and , as Incore Temperature appropriate, the acceptability will need to be confirmed. OTSG water Level (A & B)

OTSG Pressure A & B Spent Fuel Pool water level Other instruments will be maintained to confirm expected response ,

but are not required for plant control.

Source Range Nuclear Instrument Reactor Building Pressure COMPLETE.

22 3.2.1 .6.A During the ELAP and LUHS [Loss of Ultimate Heat Sink] A SOE timeline for flooding is provided as Attachment 1B beyond-design-basis external event, the licensee has The capability to perform the actions within the period identified in identified that times to complete actions in the Events analysis will be validated when the procedures are written through Timeline are based on operating judgment, the table top , simulator and field simulation exercises.

conceptual designs, and the current supporting analyses.

The TMI mitigation strategy is not based upon the Update FEB 2015 PWROG WCAP-17601-P ELAP mitigation strategy. In the audit process, the licensee stated that the current SOE is for the seismic event only and that another SOE would be developed for the flood event. Based on the information provided by the licensee, it is not possible to determine the validity of the time constraints provided in the preliminary sequence of events timeline for all hazards. The final timelines will be validated once detailed designs are completed and procedures are developed. The results will be provided in a future 6-month update.

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FEB 2014 UPDATE 23 3.2 .1.6.B The licensee will establish FLEX RCS makeup capability The analysis which provides the technical basis to conclude that at 4 within approximately 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months to maintain sufficient RCS hours action time has sufficient conservative margin has been inventory to support core heat removal. This judgment is completed . See Attachment 3.

based on expected leakage reduction from the The ability to meet this time will be validated as described in installation of low-leakage RCP seals. Conceptual design response to item 22.

for low leakage RCP seal design and analysis to confirm the time requirement to establish RCS makeup capability are not yet complete.

24 3.2.1.6.C In the sequence of events timeline, the licensee identifies The operations necessary to start the SBO diesel generator are a task to attempt to start the Station Blackout (SBO) performed inside the Unit 1 control room . The timeline for the SBO diesel generator located in Unit 2 within 5 minutes. The response described in Attachment 1A is the same as described in licensee did not explain the extent of operator actions to current licensing basis documents (UFSAR 8.5.2) .

perform this task to determine the feasibility of COMPLETE.

accomplishing this task in such a short period of time .

25 3.2.1.6.0 The licensee will revise the SOE Attachment 1A in the Attachment 1A has been revised.

February 2014 6-month update and will distinguish the COMPLETE.

time when action to start SBO is initiated from the time when the decision is made to initiate ELAP actions.

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FEB 2014 UPDATE 26 3.2 .1.9.A The licensee stated that the FLEX diesel generators (FX- The location for the FLEX diesel generators (FX-Y-1A & FX-Y-1 B)

Y-1A & B), fuel storage tank (FX-T-2) and FLEX MCC will has been moved to a new platform supported by and shielded by the be located north of the turbine pedestals on the Turbine main generator pedestals at the south end of the Turbine Building .

Building 322' elevation. The FLEX diesel generators and This location provides significantly improved seismic structural FLEX MCC will be designed for operation if subjected to support and shielding from high winds or missiles.

twice the Safe Shutdown Earthquake (SSE) , as part of The FLEX MCC has been replaced by a distribution panel , which will the "augmented approach ." Protective barriers will be be located in the vicinity of the diesels.

installed to ensure this equipment remains functional following a tornado. Feasibility analysis has been The fuel supply concept was modified . The 5000 gallon storage tank completed which shows that the Turbine Building should will only be used for flooding events. Otherwise, the fuel will be be adequate to support these loads during an SSE. supplied directly from the underground storage tank (DF-T-1) to skid Further analysis is being performed to determine if any mounted fuel tanks at FX-Y-1A & B.

structural modifications are necessary to support that COMPLETE.

conclusion.

27 3.2 .1.9.B The Integrated Plan table titled , "PWR [Pressurized These tables list equipment which is available but it may not have a Water Reactor] Portable Equipment Phase 2 ," lists two defined FLEX function . The only pumps listed in these tables which diesel driven pumps. have a required FLEX function are the two diesel driven pumps (Godwin HL 110M and HL 130M). These pumps are used to maintain The second table titled , "PWR Portable Equipment Phase a continuous condensate supply by transferring water from the river 3," lists several pumps to be obtained from the RRC.

or other on site sources to the condensate tank or the hotwell. The The licensee did not discuss how the operator actions are performance requirement for this function is satisfied with a flow of modeled in the ELAP to determine the required flow rates 150 GPM . Considering the elevation and head loss in these of the portable pumps listed in the "PWR Portable configurations, either of these pumps can easily meet the flow Equipment Phase 3", or justify that the capacities of each requirement.

of the above discussed pumps are adequate to maintain COMPLETE .

core cooling during phases 2 and 3 of ELAP.

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FEB 2014 UPDATE 28 3.2.1.9.C The licensee noted the availability of a FLEX portable The strategy for limiting RB pressure during events when the OTSG diesel driven pump, 600 gpm at 245 pounds per square is not available has been revised . A passive RB vent path will be inch differential. This pump is used to pump river water to used in lieu of an active RB cooling method. The only remaining resupply the condensate source and to provide river function for the portable diesel driven pumps is described in item 27.

water flow through a Reactor Building (RB) emergency COMPLETE.

cooler when the OTSG is not available. Condensate resupply is needed within 18 hours2.083333e-4 days 0.005 hours 2.97619e-5 weeks 6.849e-6 months . RB cooling is required within 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months after time to boil. These times are being refined . The RB cooling requirement only applies during outage conditions when additional resources will be made available . Hydraulic analysis is being completed to confirm the pump capacity is adequate for the required FLEX function.

29 3.2.1 .9.D The license stated that, for Phase 3, a portable refueling The RRC will provide the capability to airlift diesel fuel from the offsite vehicle with a large diesel oil bladder will be available on staging area to TMI utilizing a large diesel fuel bladder. On site fuel site to support refilling the portable equipment diesel distribution will be accomplished with transfer pumps (RRC) , hoses tanks. An additional means (river makeup is available) of and the on-site FLEX vehicle which has a 200 gallon supplemental delivering condensate may also be developed. fuel tank.

COMPLETE.

30 3.2.2.A The licensee stated that initial SFP cooling calculations Cooling of the spent fuel is accomplished by providing makeup water were used to determine the fuel pool timelines and that to maintain the pool level after boiling begins . The bounding values formal calculations will be performed to validate this for the spent fuel pool heat load in operating or outage conditions are information during development of the detailed design. described in the response to item 20. The time for the spent fuel pool The licensee also stated that these strategies utilize a to reach boiling was evaluated using a pre-established process for vent path for steam , and that the effects of this steam on that purpose (i .e. , ER-TM-TSC-0016).

other systems and equipment will be evaluated, and the The vent path has no interfaces with equipment relied upon for the results will be provided in a future 6-month update FLEX strategy. Therefore, potential water damage to equipment along the steam vent path to atmosphere will not adversely affect the ability to maintain core cooling , spent fuel cooling or containment.

COMPLETE.

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FEB 2014 UPDATE 31 3.2.4.1.A The licensee did not specify if the FLEX diesel generators A plan to provide portable ventilation for areas where natural on the Turbine Building were of sufficient capacity to circulation may be insufficient and key FLEX equipment performance supply any additional cooling need such as the system may be adversely affected by abnormally high ambient temperature that provides for the steam driven emergency feedwater is being prepared. Power for portable ventilation will be included to (EFW) pump bearing cooling , or any other plant establish the FLEX diesel generator capacity.

components or cooling systems needed to support the (AUG 2014 UPDATE).

FLEX strategies. Additional formal analysis is required to determine the acceptability of the licensee's plans to provide supplemental cooling to the subject areas, e.g .,

Main Control Room (MCR) , EFW room , Atmospheric Dump Valve (ADV) room , battery rooms.

32 3.2.4.2.A Habitability conditions in the MCR will be evaluated and a Portable ventilation will be utilized to improve CR habitability and strategy will be developed to maintain MCR habitability. provide cooling for key FLEX equipment. The complete plan will be The strategy and associated support analyses will be provided in the AUG 2014 UPDATE.

provided in a future 6-month update.

33 3.2.4.2.B The analysis of battery room conditions was not Portable ventilation will be utilized to prevent an excessive hydrogen complete, and the licensee noted that additional formal concentration in the battery rooms. The complete plan will be analysis to determine the acceptability of their actions provided in the AUG 2014 UPDATE.

regarding the battery room's accessibility is needed. Also additional discussion on the hydrogen gas exhaust path for each strategy is needed, and a discussion of the accumulation of hydrogen to ensure that the hydrogen gas level is below combustible level when the batteries are being recharged during Phase 2 and 3.

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FEB 2014 UPDATE 34 3.2.4.2.C The licensee did not provide any information regarding Portable ventilation will be utilized to provide cooling for key FLEX temporary cooling/ventilation for areas such as the steam equipment. The complete plan will be documented in Technical driven emergency feedwater pump room , AOV rooms or Evaluation ECR 13-00310 which will be available for review in AUG cable spreading rooms. The licensee's current strategies 2014.

are based on preliminary analysis. The current strategy for providing cooling or ventilation for these areas is to connect a permanently staged 480V AC diesel generator and fuel tanks to be located in the Turbine Building elevation 322. The strategy is to repower 1A and 1B ES MCCs in four hours and hence supply power for cooling these areas. The licensee did not provide any details regarding what ventilation systems would be repowered for these areas of the plant, or the capacity of the FLEX emergency diesel generators to meet these needs, or how this would be accomplished .

35 3.2 .4.2 .0 Provide a discussion on extreme high/low temperature A colder ambient assumption was used to provide a conservative effects on the battery capability to perform its function for result in the battery life analysis (Reference 6). An ambient the duration of ELAP event. temperature of 70F was assumed throughout the period of battery discharge. COMPLETE.

36 3.2.4.3.A The licensee specified that a strategy for extreme cold , A sequence of events timeline for an extreme cold, snow & ice is snow and ice events is being developed. Preliminary provided in Attachment 1C. This plan has two actions which are plans include the use of heat tracing for some piping and unique for this event: (1) provide power to the BWST heat trace tanks, e.g. the Borated Water Storage Tank, and circuits AND (2) connect a hose to route steam into the condensate minimum flow paths or steam heating in other situations, tank. Other actions are common for other events . COMPLETE.

e.g. the CST's. The final plans will be reviewed when complete.

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FEB 2014 UPDATE 37 3.2.4.4.A The licensee plans and strategies include providing For actions required in the first eight hours, lighting will be provided power to installed emergency lighting via the permanently by battery supplied lighting, either installed or portable .

installed FLEX emergency generators. The licensee has COMPLETE.

not completed the final analysis for the time constraints noted in the SOE therefore the timing of the need for use of the emergency generators to supply emergency lighting cannot be determined.

38 3.2.4.4.B The NRC staff reviewed the licensee communications FEB 2015 UPDATE assessment and has determined that the assessment for communications is reasonable, and the analyzed existing systems, proposed enhancements , and interim measures will help to ensure that communications are maintained .

Therefore, there is reasonable assurance that the guidance and strategies developed by Exelon will conform to the guidance of NEI 12-06 Section 3.2.2 (8) regarding communications capabilities during an ELAP.

Confirmation that upgrades to the site's communications systems have been completed will be accomplished.

39 3.2.4.5.A The licensee provided no information in the Integrated FEB 2015 UPDATE Plan regarding local access to the protected areas under ELAP.

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FEB 2014 UPDATE 40 3.2.4.6.A The licensee's analysis regarding access to the MCR , AUG 2014 UPDATE and battery rooms, is preliminary and additional formal analysis is required. In the audit process the licensee specified that temporary ventilation (fans and flexible ducts) will be used to maintain control room habitability, to control the ambient temperature in control building areas with credited FLEX electrical equipment and to limit the accumulation of hydrogen during battery charging .

This approach uses a "once through" air flow path. The licensee stated that the technical basis to demonstrate that this temporary capability is sufficient and that supporting documentation, ECR [engineering change Requestj13-00310 , will be made available to NRC when it is completed.

41 3.2.4.8.A In the audit process the licensee specified that the FLEX The maximum required electrical load for the FLEX power supply is electrical power system (480V ac diesel generators and summarized in Attachment 4.

new MCC) will be designed to handle the appropriate COIMPLETE loads. The load sizing calculations will be reviewed when provided by the licensee.

42 3.2.4.10.A The licensee stated that their load shedding analysis was C-11 01-734-E420-009 "Extending Battery Life to 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months during an based on a preliminary calculation , and the final ELAP" is available for review.

calculation results could differ from initial assumptions and could therefore provide different outcomes regarding DC load shedding strategies. No supporting information was provided regarding the analysis in calculation C-1101-734-E420-009.

43 3.2.4.10.B Provide basis for the minimum dc voltage at the dc bus In the battery life analysis (Reference 6) a minimum acceptable that will be required to ensure proper operation of all the voltage of 105VDC at the battery was used to ensure proper electrical equipment. operation of all the electrical equipment. This is the minimum voltage used in the station design basis battery life analysis. COMPLETE.

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FEB 2014 UPDATE 44 3.3.2.A The licensee provided insufficient information to conclude The TMI FLEX strategy and the engineering basis are documented in that configuration control of equipment and connections a site program document which will be issued to support will be in conformance with the guidance of NEI12-06, implementation. The modification design review process will be Section 11 .8, Items 1, 2 and 3. modified to recognize the FLEX program documents to ensure the strategy is maintained through future modification.

45 3.3.3.A The specific procedures for training, new or revised, have FEB 2015 UPDATE not yet been completed. The requirements from the analysis will be used to develop and to validate the new and revised procedures. This includes the existing design and licensing basis requirements and the new FLEX requirements. Validation of time response is performed using a composite of field simulation and performance/simulator exercises.

46 3.4.A The licensee's plans for the use of off-site resources FEB 2015 UPDATE conform to the minimum capabilities specified in NEI 12-06 Section 12.2, with regard to the capability to obtain equipment and commodities to sustain and backup the site's coping strategies, item 1. The licensee did not address the remaining items, 2 through 10 of Section 12.2.

Page 23 of 46

7 Potential Draft Safety Evaluation Impacts No potential impact to the Draft Safety Evaluation was identified.

8 References The following references support the updates to the Overall Integrated Plan described in this 6-month update.

1. Three Mile Island Nuclear Station, Unit 1, 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 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. NEI 12-06, Rev. 0, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide, dated August 2012.

4. TM-FLEX-002, Reactor Building Pressure Analysis for FLEX, Rev. 0

5. TMI Station's First Six Month Status Report for the Implementation of FLEX, dated August 28, 2013.

6. C-11 01-734-E420-009 "Extending Battery Life to 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months during an ELAP" Page 24 of 46

9 Attachments 1A Sequence of Events Timeline Earthquake or Tornado @ 100% power 18 Sequence of Events Timeline External Flood @ 100% power 1C Sequence of Events Timeline Extreme Cold, Snow and Ice @ 100% power 2A 1E-919-21-001 , draft, FLEX Diesel Generator and Fuel Oil System 28 1E-919-21-002, draft, FLEX Electrical Distribution 2C 1E-919-21-003, draft, FLEX Feedwater System 20 1E-919-21-004, draft, FLEX RCS and SFP Makeup System 3 ISE Open Item Response 4 FLEX Power Supply - Electrical Load Summary Page 25 of 46

Attachment 1A - Sequence of Events Timeline Earthquake or Tornado @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 1 0 Earthquake or tornado Causes LOOP and NA damages unprotected equipment All control rods are inserted and the reactor is shutdown.

2 0 Emergency Diesel Generators fail to energize ES NA Failures per NEI 12-06 buses.

3 < .01 EFW actuated: Steam driven pump (EF-P-1) and N Automatic plant response EFW Control valves (EF-V-30A & B) supply feedwater. MSSV & ADV control OTSG pressure 4 <.02 EOP initiated NA 5 < 0.05 RCS Letdown is automatically isolated on high N Automatic plant response temperature (MU-V-3 closes).

6 < 0.08 Control Room operators throttle ADV to stabilize N OTSG pressure and RCS temperature. Adequate core cooling is provided through RCS natural circulation and heat removal through the OTSG.

7 < 0.08 Control Room operators attempt to start and load N SBO Diesel Generator 8 < 0.10 Control Room operator closes RCP Controlled N Contains RCS losses within Bleed Off Isolation Valve (MU-V-26) the Reactor Bldg.

9 < 0.17 SBO Diesel generator is not functional N Failure per NEI 12-06.

10 0.25 Operator initiates Eplan. If needed, satellite N phones are used for offsite notifications &

communication 11 0.25 Operators open main condenser vacuum breaker Y This is a pre-condition to (VA-V-8) and valves to vent Main Generator H2 reduce DC loads.

to atmosphere 12 0.25 Control Room operator secures DC powered FW Y DC Load shedding pump turbine lube oil pumps (LO-P-9A & B) 13 0.5 Operator opens doors to inverter and battery N Maintain acceptable rooms. temperature for FLEX equipment Page 26 of 46

Attachment 1 A - Sequence of Events Timeline Earthquake or Tornado @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 14 0.5 Operator de-energizes instrument systems not . Y DC Load shedding required for FLEX.

15 < 0.75 Operator lines up C02 purge for main generator N Minimize risk of main generator fire 16 < 0.75 If condensate is lost due to damaged hotwell or Y Minimize loss of piping , then operator closes CO-V-8, CO-V-108 condensate and CO-V-24 If both CO-T-1A and CO-T-1 B are damaged , then operator closes CO-V-10B and opens DW-V-35 to line up DW-T-2 to EF-P-1 17 < 1.0 If necessary, operators secures fire service Y Mitigates the effects of non pumps (FS-P-1 and FS-P-3) seismic piping failures in Class I buildings.

18 1.0 Control room operator secures Main Turbine Lube Y DC load shedding Oil Pump LO-P-6 19 1.5 Operator lines up FLEX Diesel Generator Y Pre-condition to maintain vital AC power and restore RCS makeup 20 < 2.0 Control room operator secures Main Generator Y DC load shedding Seal Oil Pump (GN-P-2).

21 2.0 Operator props open doors for initial intermediate N building ventilation 22 2.0 Operator lines up FLEX RCS Makeup Pump from Y Pre-condition to maintain BWST or Spent Fuel Pool to RCS vital AC power and restore RCS makeup 23 2 .0 Operator takes local control of MS-V-6 (EF-P-1 Y Bottled air system will last steam supply) , EF-V-30A & EF-V-30B (EFW Flow at least 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months , and then Control Valves) and MS-V-4A & MS-V-4B local manual control is (Atmospheric Dump Valves) required .

24 2.25 Operator strips loads from 1 P & 1S 480V Buses, Y Pre-condition to maintain and 1A & 1 B ES MCC to prepare to load FLEX vital AC power and restore diesel generator RCS makeup 25 2.5 Operator starts FLEX Diesel Generator, energizes Y Pre-condition to maintain FLEX MCC and closes breakers to energize 1P- vital AC power and restore 1S 480V cross tie bus RCS makeup Page 27 of 46

Attachment 1A - Sequence of Events Timeline Earthquake or Tornado @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 26 2.58 Operator closes breakers to energize 1P 480V Y Pre-condition to maintain Bus, 1S 480V Bus, 1A ES MCC and 1B ES MCC vital AC power and restore RCS makeup 27 2.75 Operator closes breakers for selected loads on 1A Y Pre-condition to maintain and 1B ES MCC vital AC power and restore RCS makeup Battery Chargers AC Power to Inverters & Vital Instruments FLEX RCS Makeup Pumps Emergency Lighting 28 3.0 Operator starts FLEX RCS Makeup Pump (A or B) Y Restore makeup within 4 to restore RCS inventory and increase RCS boron hours to prevent interruption concentration. of core cooling.

29 3.5 Operator opens service bldg and turbine bldg N machine shop roll up doors and aux boiler roll up door.

30 4.0 Operator connects hose from DF-V-41 to pipe in Y Required for continued DGB, connects hose to fuel oil pipe in TB, and operation of FX-Y-1A or B routes hose to FLEX DG Fuel Oil Tank (FX-T-3A or B) 31 4.0 Operator strips loads on 1A ESV MCC & 1A N Pre-condition to isolate Radwaste MCC and installs jumper between 1A RCP controlled bleed off ESV MCC and 1A Radwaste MCC flow .

32 4.0 Operator starts DF-P-1 Cor DF-P-1 0 , as needed , Y Required for continued to maintain level in FX-T-3A and B. operation of FX-Y-1A or B.

Pre-staged fuel supply will last 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months at full load.

33 4.5 Operator energizes1A ESV MCC and 1A N Isolate RCP controlled Radwaste MCC, and Closes CBO Isolation Valves bleed off flow to minimize MU-V-33A, MU-V-33B, MU-V-33C and MU-V-33D RCS loss rate.

34 5.0 When pressurizer level reaches 100 inches, N operator throttles open MS-V-4A & B to initiate a cooldown and controls pressurizer level at 100 inches. Cool down rate will be less than 30 F/HR.

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Attachment 1A - Sequence of Events Timeline Earthquake or Tornado @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 35 5.0 Operator sets up and starts temporary ventilation N in Control Bldg , IB and Turbine Bldg 36 7.0 Operator strips loads on 1C ESV MCC, energizes N Contingency action 1C ESV MCC, and closes breakers for CF-V-1A and CF-V-1 B.

When a reliable Pzr steam bubble is established or If RCS pressure drops below 300 psig , then CLOSE CF-V-1A & CF-V-1 B .

37 7 to 8 Operator transfers a pressurizer heater group N Hydraulic control of RCS (RC-HTR-GRP- 8 or 9) to the emergency power pressure can be used if supply and energizes heaters required 38 8.0 Operator connects hose from FX-P-2A & B pump N This is a pre-condition to discharge to FLEX feedwater header, connects use backup feedwater power cable to FX-P-2A or B starter, opens FX-V- capability.

203, FX-V-205, EF-V-67A and EF-V-67B.

39 8 to 11 Transfer portable diesel-driven pump (FX-P-3 or Y For a tornado, minimum

4) from FLEX storage facility (FSF) to road next to condensate supply would the river or eirc water flume , route suction hose last greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

into river/flume , and route discharge hose to CO-The minimum supply is T -1 B or hotwell.

greater for an earthquake.

40 < 10.0 OTSG Pressure is now less than 200 psig. N Design objective is to be Backup feedwater capability is enabled . If backup able to establish a backup feedwater is required , operator starts FX-P-2A or with 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

B and throttles opens FX-V-206A and FX-V-206B to control OTSG level (all action TB 322 north) .

41 10.0 RCS cooldown is complete. N

Incore temperature 400F

OTSG A & B Pressure 150 psig

RCS Pressure 400 psig 42 12.0 Operator opens SF-V-88, connects hose from Y Spent fuel pool boiling FLEX feedwater header to the FLEX primary low occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

pressure header, monitors SF pool level and throttles FX-V-101 open as needed to maintain SFP level.

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Attachment 1A - Sequence of Events Timeline Earthquake or Tornado @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 43 15.0 Operator lines up spent fuel pool vent path Y Spent fuel pool boiling occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

(opening doors through U2 fuel pool to atmosphere) 44 24.0 RRC (Regional Response Center) resources N On site fuel supply is begin arriving on site. sufficient for greater than 2 weeks.

RRC Equipment will be used to maintain a reliable condensate supply and to address longer term If BWST is damaged by needs for fuel oil or borated water. tornado, then a borated water supply will be required.

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Attachment 1 B - Sequence of Events Timeline External Flood @ 100% power

ELAP Action Time Remarks I Time (only selected actions in AOP-002 listed) Constraint Applicability (HR)

YIN 1 -36 Forecast indicates river level could exceed the height of NA Plant @ 100% power the dike within the next 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . Emergency procedure OP-TM-AOP-002 "Flood" initiated.

2 -35 to Operators maximize condensate tank Note 1 (CO-T-1A & CO-T-1 B) and demineralized water tank

-12 (DW-T-2) inventory.

3 -30 Operators install drain plugs, close drain valves and Note 1 inflate seals for AB & FHB Missile shield doors 4 - 30 to - Operator connects hose from DF-V-41 to pipe in DGB, Note 1 DF-P-1 C can fill FX-T-2 in 18 connects hose to fuel oil pipe in TB, and routes hose to approx 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months FLEX DG Fuel Oil Tank (FX-T-2).

Operator starts DF- P-1 C and initiates fill of FX -T-2 5 - 30 to- Maintenance installs flood barriers and stages, Note 1 12 consumables within the flood protected area 6 - 22 to - Maintenance installs U2 flood barriers and stages, Note 1 2 consumables within the flood protected area 7 - 20 Plant shutdown and cooldown initiated Y 8 - 19 to Vent the main generator hydrogen and purge with CO2 N

- 12 9 -18 Reactor is shutdown Y 10 -16 RC-P-1 C and RC-P-1 0 shutdown and cooldown initiated N 11 -13 RCS cooldown terminated N

- RCS temperature at 390F

- RCS pressure 425 psig

- Pressurizer level 200 to 220 inches

- CF-V-1A & B closed

- MU-V-33C & 0 closed

- OTSG pressure A & B at 175 psig

- OTSG Level A & B at 97 to 99 % op rg 12 -10 RCS boron concentration exceeds cold shutdown boron N concentration requirement 13 -9 to -8 Operator transfers a pressurizer heater group Note 1 (RC-HTR-GRP- 8 or 9) to the ES power supply

-6 Operator connects hose from FX-P-2A & B pump Note 1 discharge to FLEX feedwater header, connects power 14 cable to FX-P-2A or B starter, opens FX-V-203, FX-V-205, EF-V-67A and EF-V-67B.

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Attachment 1 B - Sequence of Events Timeline External Flood @ 1000/0 power

ELAP Action Time Remarks I Time (only selected actions in AOP-002 listed) Constraint Applicability (HR)

YIN 15 -4 Operator lines up FX-P-1A & B path from BWST to RCS Note 1 Operator connects hose from FLEX feedwater header to the FLEX primary low pressure header, and lines up FLEX makeup to the SF pool.

16 -3 Operator connects power cable to FX-P-5A or Band Note 1 hose from FX-P-5A & B discharge to FX-T-3A or B.

17 -2 Operator opens breakers for BWST tunnel sump pumps Note 1 and closes WDL-V-612 18 -1 Operator strips unprotected DC circuits from DC system Note 1 Prevents loss of battery (OP-TM-734-903 & 904) capacity 19 0 River level exceeds the height of the dike. NA Failures per NEI 12-06 LOOP occurs and Emergency Diesel Generators fail to energize ES buses.

20 0 EFW actuated: Steam driven pump (EF-P-1) starts and NA Automatic plant response EFW Control valves (EF-V-30A & B) are available to supply feedwater. RCS hot leg and cold leg temperatures diverge. OTSG pressure is dropping slowly.

21 < .02 EOP initiated NA 22 < 0.05 Let.down isolates (MU-V-3) automatically on high NA Automatic plant response temperature.

23 < 0.08 Control Room operators throttle ADV to reduce OTSG N pressure, maintain OTSG level with EFW control valves ,

and stabilize RCS temperature. Adequate core cooling is provided through RCS natural circulation and heat removal through the OTSG . RCS conditions follow:

- RCS temperature at 400F

- RCS pressure 425 psig

- Pressurizer level 200 to 220 inches

- OTSG pressure A & B at 150 psig

- OTSG Level A & B is at "flooded nozzle" (97 to 99 % operating range) 24 < 0.08 Control Room operators attempt to start and load SBO N Diesel Generator 25 < 0.10 Control Room operator closes RCP Controlled Bleed Off N Contain RCS losses Isolation Valve (MU-V-26) within Reactor Bldg.

Page 32 of 46

Attachment 1 B - Sequence of Events Timeline External Flood @ 1000/0 power

ELAP Action Time Remarks I Time (only selected actions in AOP-002 listed) Constraint Applicability (HR)

YIN 26 < 0.17 Control room operators recognize SBO Diesel generator N Failure per NEI 12-06.

is not functional 27 0.25 Operator performs E-plan offsite notifications & N communication using satellite phones 28 < 0.25 Operator close FS-V-256 & FS-V-257 to terminate N IA-P-1 A & B cooling water flow into I B sump 29 < 0.5 Operator lines up FLEX Diesel Generator Y Pre-condition to maintain vital AC power and restore RCS makeup 30 0.5 Operator opens doors to inverter and battery rooms for N Maintain acceptable FLEX ventilation. equipment cooling 31 .75 Operator strips loads from 1 P & 1S 480V Buses, and 1A Y Pre-condition to maintain

& 1B ES MCC to prepare to load FLEX diesel generator vital AC power and

. restore RCS makeup 32 < 1.0 Operator starts FLEX Diesel Generator, energizes FLEX Y Pre-condition to maintain Distribution Panel and closes breakers to energize 1 P- vital AC power and 1S 480V cross tie bus restore RCS makeup 33 1.0 Operator closes breakers to energize 1P 480V Bus , 1S Y Pre-condition to maintain 480V Bus, 1A ES MCC and 1B ES MCC vital AC power and restore RCS makeup 34 1.25 Operator closes breakers for selected loads on 1A and Y Pre-condition to maintain 1B ES MCC vital AC power and

- Battery Chargers restore RCS makeup

- AC Power to Inverters & Vital Instruments

- FLEX ReS Makeup Pumps

- Emergency Lighting

- Pressurizer heater group 35 1.5 Operator starts FLEX RCS Makeup Pump (A or B) and Y Objective to restore throttles FX-V-103A (B) to maintain pressurizer level makeup with 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is above 200 inches conservative 36 2.0 If backup feedwater is required, then operator starts N FX-P-2A or B and throttles open FX-V-206A and FX-V-206B to control OTSG level.

37 2.0 Operator takes local control of MS-V-6 (EF-P-1 steam Y Bottled air system will last supply) , EF-V-30A & EF-V-30B (EFW Flow Control at least 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months , and then Valves) and MS-V-4A & MS-V-4B (Atmospheric Dump manual control is Valves) required .

Page 33 of 46

Attachment 1 B - Sequence of Events Timeline External Flood @ 100% power

ELAP Action Time Remarks I Time (only selected actions in AOP-002 listed) Constraint Applicability (HR)

YIN 38 2.5 Operator strips loads on 1A ESV MCC and installs N jumper between 1A ESV MCC and 1A Radwaste MCC 39 3.0 Operator energizes1A ESV MCC and 1A Radwaste N MCC, and Closes CBO Isolation Valves MU-V-33A and MU-V-33B 40 3.5 Operator starts FX-P-5A or B, as needed, to maintain Y Required for continued level in FX-T-3A and B. operation of FX-Y-1A or B. Pre-staged fuel supply will last 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months at full load.

41 4.0 Operator sets up and starts temporary ventilation in CB, N IB and TB.

42 15.0 Operator lines up spent fuel pool vent path Y Spent fuel pool boiling occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

(opening doors through U2 fuel pool to atmosphere) 43 24.0 RRC (Regional Response Center) resources available N

.. .Iimited capability to transport any resources until 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months due to water level on site 44 > 24 Operator throttles open FX-V-101 as needed to maintain Y Spent fuel pool boiling SFP level. occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

45 96 Transfer portable diesel-driven pump (FX-P-3 or 4) from Y Minimum condensate FLEX storage facility (FSF) to road next to the river, supply would last greater route suction hose into river, and route discharge hose than 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months after water to CO-T-1 B. recedes (at 72 hrs).

NOTE 1: In the event of a flood, additional resources are applied to ensure the proactive actions can be completed within the described timeline.

Page 34 of 46

Attachment 1C - Sequence of Events Timeline Extreme Cold, Snow and Ice @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN

-8 Weather predicts extreme cold conditions NA Staff augmentation is initiated

-4 Staff augmentation is complete NA 1 0 Extreme cold, snow or ice causes LOOP NA All control rods are inserted and the reactor is shutdown.

2 0 Emergency Diesel Generators fail to energize ES NA Failures per NEI 12-06 buses .

3 <.01 EFW actuated: Steam driven pump (EF-P-1) and N Automatic plant response EFW Control valves (EF-V-30A & B) supply feedwater. MSSV & ADV control OTSG pressure 4 <.02 EOP initiated NA 5 < 0.05 RCS Letdown is automatically isolated on high N Automatic plant response temperature (MU-V-3 closes) .

6 < 0.08 Control Room operators throttle ADV to stabilize N OTSG pressure and RCS temperature. Adequate core cooling is provided through RCS natural circulation and heat removal through the OTSG .

7 < 0.08 Control Room operators attempt to start and load N SBO Diesel Generator 8 < 0.1 0 Control Room operator closes RCP Controlled N Contains RCS losses within Bleed Off Isolation Valve (MU-V-26) the Reactor Bldg.

9 < 0.17 SBO Diesel generator is not functional N Failure per NEI 12-06.

10 0.25 Operator initiates E-plan . If needed, satellite N phones are used for offsite notifications &

communication 11 0.25 Operators open main condenser vacuum breaker Y This is a pre-condition to (VA-V-8) and valves to vent Main Generator H2 reduce DC loads.

to atmosphere 12 0.25 Control Room operator secures DC powered FW Y DC Load shedding pump lube oil pumps (LO-P-9A and LO-P-9B)

Page 35 of 46

Attachment 1C - Sequence of Events Timeline Extreme Cold, Snow and Ice @ 100% power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 13 0.5 Operator opens doors to inverter and battery N rooms .

14 0.5 Operator de-energizes instrument systems not Y DC Load shedding required for FLEX.

15 < 0.75 Operator lines up C02 purge for main generator N Minimize risk of main generator fire 16 1.0 Control room operator secures Main Turbine Lube Y DC load shedding Oil Pump LO-P-6 17 1.5 Operator lines up FLEX Diesel Generator Y Pre-condition to maintain vital AC power and restore RCS makeup.

18 < 2.0 Control room operator secures Main Generator Y DC load shedding Seal Oil Pump (GN-P-2).

19 2.0 Operator lines up FLEX RCS Makeup Pump from Y Pre-condition to restore BWSTto RCS RCS makeup.

20 2.0 Operator takes local control of MS-V-6 (EF-P-1 Y Bottled air system will last steam supply) , EF-V-30A & EF-V-30B (EFW Flow at least 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months , and then Control Valves) and MS-V-4A & MS-V-4B manual control is required .

(Atmospheric Dump Valves) 21 2.25 Operator strips loads from 1 P & 1S 480V Buses, Y Pre-condition to maintain and 1A & 1 B ES MCC to prepare to load FLEX vital AC power and restore diesel generator RCS makeup .

22 2.5 Operator starts FLEX Diesel Generator, energizes Y Pre-condition to maintain FLEX MCC and closes breakers to energize 1 P- vital AC power and restore 1S 480V cross tie bus RCS makeup.

23 2 .58 Operator closes breakers to energize 1 P 480V Y Pre-condition to maintain Bus, 1S 480V Bus , 1A ES MCC and 1B ES MCC vital AC power and restore RCS makeup.

24 2.75 Operator closes breakers for selected loads on 1A Y Pre-condition to maintain and 1B ES MCC vital AC power and restore Battery Chargers RCS makeup.

AC Power to Inverters & Vital Instruments FLEX RCS Makeup Pumps Emergency Lighting Page 36 of 46

Attachment 1C - Sequence of Events Timeline Extreme Cold, Snow and Ice @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 25 3.0 Operator starts FLEX RCS Makeup Pump (A or B) Y Restore makeup within 4 to restore RCS inventory and increase RCS boron hours to prevent interruption concentration. of core cooling.

26 4.0 Operator connects hose from DF-V-41 to pipe in Y Pre-condition to maintain DGB, connects hose to fuel oil pipe in TB, and fuel supply to FX-Y-1A or B routes hose to FLEX DG Fuel Oil Tank (FX-T-3A or B) 27 4.0 Operator strips loads on 1A ESV MCC & 1A N Radwaste MCC and installs jumper between 1A ESV MCC and 1A Radwaste MCC. Operator ensures BWST heat trace is energized.

28 4.0 Operator starts DF-P-1 Cor DF-P-1D, as needed , Y Required for continued to maintain level in FX-T-3A and B. operation of FX-Y-1A or B.

Pre-staged fuel supply will last 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months at full load.

29 4.5 Operator energizes1A ESV MCC and 1A N Isolate RCP controlled Radwaste MCC, and Closes CBO Isolation Valves bleed off flow to minimize MU-V-33A, MU-V-33B, MU-V-33C and MU-V-33D RCS loss rate.

30 5.0 When pressurizer level reaches 100 inches, then N Pre-condition to enable operator throttles open MS-V-4A & B to initiate a back-op feedwater cool down and controls pressurizer level at 100 capability.

inches. Cooldown rate will be less than 30 F/HR 31 7.0 Operator strips loads on 1C ESV MCC, energizes N Contingency actions 1C ESV MCC, and closes breakers for CF-V-1A and CF-V-1 B.

When a reliable steam bubble is established or if RCS pressure drops below 300 psig, then CLOSE CF-V-1A & CF-V-1B .

32 7 to 8 Operator transfers a pressurizer heater group N Hydraulic control of RCS (RC-HTR-GRP- 8 or 9) to the emergency power pressure can be used if supply and energizes heaters required.

33 8.0 Operator connects hose from FX-P-2A & B pump N Pre-condition to enable discharge to FLEX feedwater header, connects back-op feedwater power cable to FX-P-2A or B starter, opens FX-V- capability.

203, FX-V-205, EF-V-67A and EF-V-67B.

Page 37 of 46

Attachment 1C - Sequence of Events Timeline Extreme Cold, Snow and Ice @ 1000/0 power

ELAP Action Time Remarks I Time Constraint Applicability (HR)

YIN 34 < 10.0 OTSG Pressure is now less than 200 psig. N The design objective is to Backup feedwater capability is enabled . If backup enable back-op feedwater feedwater is required, operator starts FX-P-2A or capability within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

B and throttles opens FX-V-206A and FX-V-206B to control OTSG level (all action TB 322 north) .

35 10.0 RCS cooldown is complete. N

Incore temperature 400F

OTSG A & B Pressure 150 psig

RCS Pressure 400 psig 36 12.0 Operator connects a hose from main steam drain N line to piping connected to condensate tank Band initiates tank heating.

37 12.0 Operator opens SF-V-88, connects hose from Y Spent fuel pool boiling FLEX feedwater header to the FLEX primary low occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

pressure header, monitors SF pool level and throttles FX-V-101 open as needed to maintain SFP level.

38 15.0 Operator lines up spent fuel pool vent path Y Spent fuel pool boiling (opening doors through U2 fuel pool to occurs after 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months .

atmosphere) 39 24.0 RRC (Regional Response Center) resources N begin arriving on site.

RRC Equipment will be used to maintain a reliable condensate supply and to address longer term needs for fuel oil or borated water.

40 48 Transfer hose and portable diesel-driven pump Y Minimum condensate (FX-P-3 or 4) from FLEX storage facility (FSF) to supply would last greater road next to the river, route suction hose into river, than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

and route discharge hose to CO-T -1B.

Page 38 of 46

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Page 39 of 46

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Page 42 of 46

Attachment 3 Interim Staff Evaluation Open Items NRC issued their Interim Staff Evaluation for the TMI-1 Plan for compliance with Order EA 12-049 on December 17, 2013. The Interim Staff Evaluation (ISE) identified four open items. This document provides specific details of the TMI plan in response to those items. (1 &2) Describe the basis that RCS inventory will remain adequate for core cooling based on WCAP 17792 (3) An alternate method for evaluation of available condensate sources and (4) An alternate approach using pre-staged diesel generators.

OPEN ITEMS #1 & 2 The ISE items 3.2.1.1.B and 3.2.1 .1.C requested the following: "Provide the analysis supporting the licensee's mitigation strategy (WCAP-17792-P) for NRC staff review, identify the specific calculation(s) in WCAP-17792 considered applicable to demonstrating the feasibility of the proposed strategy, and justify the applicability of the calculation(s) relied upon in WCAP-17792 to TMI-1." and "As applicable, provide additional analyses for core cooling, RCS makeup, and shutdown margin that are relied upon , but not included in WCAP-17792-P."

The TMI FLEX strategy is to restore RCS makeup within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months (Le. , prior to the loss of RCS heat transfer). This approach is founded on previous analysis and testing which demonstrates sub-cooled natural circulation can provide stable effective core cooling. The TMI FLEX strategy objective to restore RCS makeup within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is supported by MAAP analysis and PWROG analysis described in WCAP 17792P.

The time from the ELAP occurrence until the point at which the loss of RCS inventory could interrupt natural circulation was conservatively estimated using MAAP. For this analysis, RCS leakage was assumed to be 20 GPM (with RCS at normal operating pressure of 2155 psig). Design and testing of the Flowserve N-9000 seal indicate that the total loss rate through the seal package (controlled bleed off flow and seal leakage) would be less than 11 GPM @ 2155 psig. The MAAP analysis showed there is greater than 6.5 hrs before water level in either hot leg reaches 3 inches above the bottom of the hot leg.

WCAP 17792P, Figure C.5-2 "ELAP Estimated Time to LOHT for 400" Pressurizer Scale Plants" provides a method to estimate the time until loss of heat transfer following an ELAP. The WCAP method used generic bounding plant design parameters, and conservatively ignores the water inventory in the pressurizer below 0" indication. Of the two B&W designs, TMI -1 has a pressurizer with a 400 inch measurement scale. To use the WCAP Figure the RCS loss rate (11 GPM) is converted to a "Pressurizer Level Rate of Change" of 0.46 inches/min based on a pressurizer inside diameter of 84 inches, and an initial post reactor trip pressurizer level of 100 inches. 100" is a conservative estimate of pressurizer level following an ELAP or LOOP where T AVG is significantly higher due to the lack of forced RCS flow. Using WCAP 17792P, Figure C.5-2 , the "Time to Loss of Heat Transfer" is approx. 5 .5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months .

The TMI FLEX strategy is to provide borated water (> 2500 ppmB) at a rate in excess of RCS losses within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . This ensures RCS conditions can be maintained to support continued sub-cooled natural circulation and RCS heat removal via the OTSG , and raises RCS boron concentration to ensure the reactor remains shutdown. Cycle specific reactivity analysis has been completed which demonstrates that when all control rods insert and RCS inventory is maintained during cooldown using borated water of at least 2500 ppmB, then the reactor will remain shutdown at cold (72F) conditions without Xenon. The TMI strategy injects additional boron to compensate for RCS losses. This adds shutdown marg in beyond that credited in the analysis completed.

Page 43 of 46

Attachment 3 Interim Staff Evaluation Open Items

References:

TM-FLEX-001 "Core Cooling Analysis for FLEX" WCAP-17792-P "Emergency Procedure Development Strategies for Extended Loss of AC power Event for all Domestic Pressurized Water Reactor Designs", draft Sept 2013 C-1101-202-E620-471 "TMI-1 Cycle-Specific Shutdown Margin Verification during Emergency Cooldown" OPEN ITEM #3 The ISE described item 3.2.4.7.A as "The licensee appears to use a probabilistic approach to reach a conclusion that at least one of the three tanks depended on for RCS makeup will survive an ELAP event. NEI 12-06 guidance does not include this option . Provide further justification for this alternate approach."

NEI 12-063.2.1.3.3 "Cooling and makeup water inventories contained in systems or structures with designs that are robust with respect to seismic events, floods, and high winds, and associated missiles are available."

All of the condensate source relied upon for the TMI BDBEE Mitigation strategy were not protected by design from high wind conditions but as described below there is reasonable assurance that one or more of these three sources would be available after a high wind event. This is an alternate strategy which complies with Order EA 12-049.

The applicable high wind hazard based on the TMI-1 geographical location and Regulatory Guide 1.76 is a tornado wind speed of 200 mph. 95% of the tornadoes recorded by NOAA in the last 60 years within a 50 miles radius of TMI had a maximum estimated wind speed of 157 mph or less. The condensate storage tanks (CO-T -1 A and CO-T -1B) are designed to withstand design basis tornado wind loads of 300 mph . Both condensate storage tanks will mainrain their integrity when subjected to wind load from a tornado. The demineralized water storage tank (DW-T-2) is capable of withstanding a tornado wind speed of 185 mph. In the event of high winds (either from hurricane or tornado) , both condensate storage tanks will be available and it is very likely that DW-T-2 will remain available.

The condensate storage tanks and DW -T -2 were not protected by design against tornado-generated missiles. However, there is reasonable assurance that one or more of these three tanks would not be damaged by wind generated missiles. This conclusion is based similar considerations as described for protecting FLEX equipment in NEI 12-06 (i.e. , the equipment is located "in diverse locations" and is "adjacent to existing robust structures", and "separation" is considered based on the "predominant path of tornados in the geographical location").

The three potential condensate source tanks are located as follows: CO-T-1 B is located northwest, CO-T-1A is located northeast and DW-T-2 is located southeast of the TMI-1 Class 1 tornado hardened structures . TMI Class 1 structures are designed for aircraft impact per plant's design basis. These structures limit the generated missile pathways and thereby minimize the probability of missile impact.

In addition to the Class I structures separating the tanks east and west, DW-T-2 is further shielded by adjacent robust structures: the Chemical Cleaning Building at the east side, the Unit 2 Auxiliary building at the west side and the Unit 2 BWST and Unit 2 Control Building from the south side.

Based on a review of historical records, the predominant tornado pathway for TMI is from southwest toward northeast. CO-T -1 B & CO-T -1 A tanks are separated by 392 feet, CO-T -1 A and DW -T -2 are separated by 430 feet, and CO-T-1 Band DW-T-2 are separated by 542 feet. The separation between CO-T-1 Band DW-T-2 is approximately perpendicular to the expected travel pathway of the tornado.

Page 44 of 46

Attachment 3 Interim Staff Evaluation Open Items Within the last 60 years, 85% of the tornados within a 50 mile radius from TMI-1 were less than 450 feet wide. Given the historical tornado width and the separation between CO-T-1 Band DW-T-2, only one of those tanks would be within the tornado path.

Therefore, based on the separation, adjacent robust structures and the predominant tornado pathway there is reasonable assurance that if a tornado was to strike TMI, one or more of these three tanks would not be damaged by wind generated missiles.

References:

(1) Technical Evaluation 13-00476 "FLEX Strategy Design Evaluation for CO-T-1A11B and DW-T-2" (2) Technical Evaluation 13-00477 "TMI-1 Tornado Study For FLEX Strategy" OPEN ITEM #4 The ISE described item 3.2.4.8.B as "On page 37 of the Integrated Plan, the licensee states that two (2) diesel generators along with Fuel Tanks will be pre-staged in a protected enclosure on the 322' elevation of the Turbine Building. Provide justification addressing the flexibility of this alternate approach to mitigate BDBEEs."

The TMI FLEX strategy complies with EA-12-049, but is an alternate approach to NEI-12-06 in that it relies upon two new installed RCS makeup pumps and two new installed diesel generators.

The new RCS makeup pumps will be installed in the tornado protected seismic Class I control bldg at 322' elevation (above the TMI site flood elevation of 313.3'). The two new diesel generators will be installed on a new platform at 322' elevation in the Turbine Building. The structure supporting the diesel generators will provide adequate support during a flood , seismic or tornado event. The diesel generators will be shielded to ensure their function is satisfied with regard to tornado winds and missiles.

The B&W RCS and Steam Generator configuration results in a challenging timeline for response to an ELAP event at TMI. Conserving RCS inventory and promptly restoring RCS makeup are key elements in the TMI FLEX strategy. RCS makeup capability (greater than RCS loss rate) will be established within four hours in order to maintain continuous core cooling. The TMI FLEX strategy is dependent on a more timely response than can be reliably implemented using portable equipment. Additionally, portable equipment and associated connections could not be staged at grade as they would be impacted by the flood event (flood level is approx. 8 feet above grade around the main plant structures).

Even though the new diverse RCS makeup and electrical power supply capabilities are installed, this approach has significant flexibility to mitigate Beyond Design Basis events . The RCS makeup pumps can utilize the safety related electrical power supply or the FLEX power supply. These pumps can use multiple water sources to inject water into the RCS. The FLEX feedwater pumps can be used to supply water to the Steam Generators, the Spent Fuel Pool or directly to the RCS in low pressure conditions.

The FLEX electrical power supply can provide power to either ES power train or the FLEX power distribution panel. These new capabilities provide significant mitigation value and flexibility for events not described in NEI 12-06 or NRC Order EA 12-049.

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Attachment 4 FLEX Power Supply - Electrical Load Summary DESCRIPTION of LOAD Max. Load (see NOTE 1) (Amps @ 480V)

Inverter lA (NOTE 3) (NOTE 4) 25 Inverter lB (NOTE 3) 21 Inverter 10 16 Battery Charger lA (NOTE 2) 45 Battery Charger lC (NOTE 2) 45 Battery Charger lB (NOTE 2) 45 Battery Charger 10 (NOTE 2) 45 Emergency Lighting (CB, TB, AB & IB) 50 OF-P-1C 0.4 FX-P-1A (or FX-P-1B) 87 FX-P-2A (or FX-P-2B) 52 BWST Heater (65 kW) 78 Pressurizer Heater Group 8 (84kW) 101 Portable Fans (4@ 1 kW and 3@ 1.5kW) 12 one of MU-V-33A,B,C,O or 5 CF-V-1A or CF-V-1B Maximum required load (480v Amps) 617 FLEX Diesel capacity SOOKW @ 0.9 pf (Amps) 668 Maximum required load as % of FLEX DG Capacity 92%

NOTE 1: This list describes the loads for the maximum required electrical load condition which occurs during an extreme cold scenario when BWST heating is required and when the OTSG is available (and Pressurizer heaters and High Pressure RCS makeup are required) .

NOTE 2: This is load while the batteries are being recharged. Once battery voltage is restored, the load is approximately 10 amps per charger.

NOTE 3: This is a conservative load which does not reflect planned load shed actions.

NOTE 4: ICS AUTO load is included with 1A Inverter. This load remains but is is transferred to the 1 E Inverter during the event as part of OC load shed actions.

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RS-14-016, Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses Re Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order EA-12-049)

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RS-14-016, Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses Re Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order EA-12-049)

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