NRC-23-0050, Exigent License Amendment Request for Technical Specification 3.7.2, Emergency Equipment Cooling Water (Eecw)/Emergency Equipment Service Water (Eesw) System and Ultimate Heat Sink (UHS)

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Exigent License Amendment Request for Technical Specification 3.7.2, Emergency Equipment Cooling Water (Eecw)/Emergency Equipment Service Water (Eesw) System and Ultimate Heat Sink (UHS)
ML23222A037
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 08/10/2023
From: Peter Dietrich
DTE Electric Company
To:
Office of Nuclear Reactor Regulation, Document Control Desk
References
NRC-23-0050
Download: ML23222A037 (1)
v • d • e


Text

Peter Dietrich Senior Vice President and Chief Nuclear Officer DTE Electric Company 6400 N. Dixie Highway, Newport, MI 48166 Tel: 734.586.6515 Email: peter.dietrich@dteenergy.com DTE 10 CFR 50.90 August 10, 2023 NRC-23-0050 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Reference:

Fermi 2 Power Plant NRC Docket No. 50-341 NRC License No. NPF-43

Subject:

Exigent License Amendment Request for Technical Specification 3.7.2, Emergency Equipment Cooling Water (EECW)/Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS)

In accordance with the provisions of Title 10 Code of Federal Regulations (10 CFR) 50.90, DTE Electric Company (DTE) requests an amendment to the Fermi 2 Plant Operating License, Appendix A, Technical Specifications (TS) 3.7.2, to allow for a one-time extension of the Condition A Completion Time to allow repair of the Division I Mechanical Draft Cooling Tower (MDCT) A and C fan pedestals while online. The proposed amendment is being requested due to an exigent circumstance pursuant to 10 CFR 50.91(a)(6).

The requested amendment would revise Limiting Condition for Operation (LCO) 3.7.2, Emergency Equipment Cooling Water (EECW)/Emergency Equipment Service Water (EESW)

System and Ultimate Heat Sink (UHS) Condition A, for one or more required subsystems inoperable, by adding a footnote to allow a one-time extension of the Completion Time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days during the current operating Cycle 22. This one-time extension would be used twice, once for each fan during the allotted time approved by the NRC.

This request is being made to be proactive and repair the Division 1 MDCT A and C fan pedestals. This repair is projected to take more than the currently allotted 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to complete and would normally require this work to be performed with the plant offline. This request is to enable DTE to perform this maintenance online and avoid a potential unnecessary plant shutdown or need for enforcement discretion without a corresponding health and safety benefit.

Therefore, DTE is requesting this amendment be approved for this exigent circumstance.

USNRC NRC-23-0050 Page 2 provides a detailed description and safety analysis to support the proposed amendment, including detailed justification for approving the amendment due to exigent circumstances, an evaluation of significant hazards considerations pursuant to 10 CFR 50.92(c),

and an environmental assessment. Enclosure 2 provides a copy of the existing TS pages marked up to show the proposed change. Enclosure 3 provides a copy of the revised clean TS page with the change incorporated. Enclosure 4 contains the DTE PRA evaluation.

DTE requests approval of the proposed amendment by September 11, 2023. The proposed amendment will be implemented within two days of the U.S. Nuclear Regulatory Commission approval. We are also requesting an expiration date of 11/19/23 for the one-time extension to support our plan to perform work on MDCT A and C separately in the Division I work weeks of 10/2/23 and 10/9/23. The additional time requested after these weeks is a scheduling contingency in case an unforeseen emergent issue results in the need to re-schedule this maintenance to subsequent Division I weeks of 10/30/23 and 11/6/23.

No new commitments are being made in this submittal.

In accordance with 10 CFR 50.91, a copy of this application, with enclosures, is being provided to the designated Michigan State Official.

Should you have any questions or require additional information, please contact Mr. Eric Frank, Manager, Licensing at (734) 586-4772.

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

Executed on August 10, 2023 Peter Dietrich Senior Vice President and Chief Nuclear Officer

Enclosures:

1. Evaluation of the Proposed License Amendment
2. Marked-up Pages of Existing Fermi 2 TS
3. Clean Pages of Fermi 2 TS with Changes Incorporated
4. DTE PRA Technical Evaluation TE-E11-23-052 cc: NRC Project Manager NRC Resident Office Regional Administrator, Region III Michigan Department of Environment, Great Lakes, and Energy

Enclosure 1 to NRC-23-0050 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Evaluation of the Proposed License Amendment to NRC-23-0050 Page 1 Evaluation of the Proposed License Amendment Contents 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION 2.1 System Design and Operation 2.2 Circumstances Establishing Need for the Proposed Exigent Amendment 2.3 Description of the Proposed Change

3.0 TECHNICAL EVALUATION

3.1 Probabilistic Risk Assessment

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements and Criteria 4.2 Precedent 4.3 No Significant Hazards Consideration 4.4 Conclusion

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

to NRC-23-0050 Page 2 1.0

SUMMARY

DESCRIPTION In accordance with the provisions of Title 10 Code of Federal Regulations (10 CFR) 50.90, DTE Electric Company (DTE) requests an amendment to the Fermi 2 Plant Operating License, Appendix A, Technical Specifications (TS) 3.7.2, to allow for a one-time extension of the Condition A Completion Time to allow repair of the Division I MDCT A and C fan pedestals while online.

This proposed one-time license amendment will add a note to Technical Specification 3.7.2 Emergency Equipment Cooling Water (EECW)/Emergency Equipment Service Water (EESW)

System and Ultimate Heat Sink (UHS) Condition A completion time to extend the time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 7 days during Cycle 22. This one-time extension would be used twice, once for each fan during the allotted time approved by the NRC.

Tech Spec Footnote:

  • The 72-hour Completion Time is extended to 7 days for each of the Division I MDCT fan pedestals (A and C) to allow repair online during Cycle 22 and will expire at 2359 on November 19, 2023.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation The EECW/EESW System is designed to provide cooling water for the removal of heat from equipment, such as residual heat removal (RHR) and Core Spray (CS), pump coolers, and room coolers for Emergency Core Cooling System (ECCS) and other safety-related equipment, required for a safe reactor shutdown following a Design Basis Accident (DBA) or transient.

Components cooled by each EECW subsystem are normally cooled by the Reactor Building Closed Cooling Water (RBCCW) system, which cools various plant equipment primarily in the Reactor Building. An EECW subsystem contains a single 1775 gpm nominal capacity pump, a heat exchanger, a make-up tank, valves, piping, and associated instrumentation. A second 100% capacity heat exchanger is also provided as a backup. Upon receipt of a loss of off-site power, a high drywell pressure signal, or low RBCCW System pressure, both EECW subsystems are activated. Upon activation, the EECW pump starts, the EECW loop isolates from the remainder of the RBCCW system, and other system valves reposition as needed to isolate non-essential loads and configure the system for emergency operation.

Each EECW subsystem's heat exchanger is cooled by the same division's EESW subsystem. The EESW subsystem contains a single 1600 gpm nominal capacity pump that pumps from the division's RHR Reservoir through the EECW subsystem's heat exchanger and returns to the RHR Reservoir. Each EESW subsystem functions to cool the associated EECW subsystem. The EESW pump automatically starts on the same actuation signals as the EECW System. The two to NRC-23-0050 Page 3 EECW/EESW subsystems are separated from each other so that failure of one subsystem will not affect the OPERABILITY of the other subsystem.

The UHS is provided by a single highly reliable water supply in the form of the RHR reservoirs and a means of heat rejection in the form of mechanical draft cooling towers. The UHS consists of two one-half capacity reinforced concrete reservoirs each with a capacity of 3.41 X 106 gallons of water, corresponding to an elevation of 583 feet. The two reservoirs are connected by two redundant cross-tie lines to provide access to the combined inventory to either division of cooled equipment in the event of a failure in one of the divisions. Each RHR reservoir is the cooling source for that division's RHRSW subsystem, and EESW subsystem, as well as the diesel generator service water pumps for that division's emergency diesel generators (EDGs). A two-cell mechanical draft cooling tower is located over each division reservoir. Each cooling tower is designed to cool one division of supported equipment, thus providing full redundancy.

2.2 Circumstances Establishing Need for the Proposed Exigent Amendment On July 18, 2023, at 0424 Eastern Daylight Time (EDT), the Division II Residual Heat Removal Service Water (RHRSW) Mechanical Draft Cooling Tower (MDCT) fan D tripped due to high vibrations caused by a degraded, non-conforming gearbox pedestal. Corrective actions were required to correct the conditions and restore the equipment to an operable status, using extra time allowed by the Notice of Enforcement Discretion (NOED) requested by our letter NRC 0049 and verbally approved by the NRC on July 20, 2023. During that time the UHS was declared inoperable. During the extent of condition review, it was discovered that the MDCT A and C fan pedestals were also degraded and non-conforming, but remained Operable, and also in need of similar repair. This request is being made to be proactive and repair the Division I MDCT A and C fan pedestals. Additionally, this request provides justification that obtaining an extension of the Completion Time to repair the Division I MDCT fan pedestals online instead of waiting until the next refueling outage. The proposed amendment is being requested due to an exigent circumstance pursuant to 10 CFR 50.91(a)(6).

2.3 Description of the Proposed Change The proposed license amendment would revise the LCO 3.7.2, Condition A Completion Time, LCO 3.8.1, Condition B Completion Time, and LCO 3.8.4, Condition A by adding the following footnotes:

LCO 3.7.2

  • The 72-hour Completion Time is extended to 7 days for each of the Division I MDCT fan pedestals (A and C) to allow repair online during Cycle 22 and will expire at 2359 on November 19, 2023.

A marked-up copy of the proposed change is provided in Enclosure 2. Enclosure 3 provides revised (clean) pages.

to NRC-23-0050 Page 4

3.0 TECHNICAL EVALUATION

The proposed change does not alter the plant design, nor does it affect the assumptions contained in the safety analyses. Specifically, there are no changes being made to the fan pedestal design.

As described in the UFSAR sections noted below, the following conditions have been previously analyzed.

Technical Specification Requirements (TS 3.7.2)

In MODEs 1, 2, and 3, the Fermi 2 TS 3.7.2, Emergency Equipment Cooling Water (EECW)

/Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS), requires two EECW/EESW subsystems and UHS to be operable. When one or more are inoperable, the following TS 3.7.2 Condition applies:

A.1 - Restore reservoir to OPERABLE status.

If REQUIRED ACTION A.1 cannot be completed within its 72-hour COMPLETION TIME, then TS 3.7.2 CONDITION C applies. CONDITION C contains two REQUIRED ACTIONS, C.1, to be in MODE 3 with a Completion Time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and C.2, to be in MODE 4 with a COMPLETION TIME of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

System Description (UFSAR 9.2.5.2.2)

A two-cell induced-draft cooling tower is located over each division reservoir of the Ultimate Heat Sink (UHS). The towers are of Category I fireproof construction with reinforced-concrete shells, cement board fill, and mist eliminators. Each tower is designed to cool one division of the plant load (one Residual Heat Removal (RHR) heat exchanger, one EECW heat exchanger, and two Emergency Diesel Generators (EDGs)), thus providing complete redundancy. Component design parameters for each tower are given in UFSAR Table 9.2-7.

Each RHRSW cooling tower cell fan is driven by a 150-hp two-speed motor. The motor is connected to the Engineered Safety Feature (ESF) bus of the EDGs for a redundant power supply and is manually started and stopped from the main control room.

The towers and fan drives are provided with a reinforced-concrete protective shell for tornado, earthquake, and missile protection.

Operation With One Division Unavailable (UFSAR 3.5.1.3.2.2 & 3.8.4.1.2)

The Mechanical Draft Cooling Tower system is designed such that it can function even if one tower division is damaged, rendered out of service, or is unavailable. With the two divisional reservoirs of the Ultimate Heat Sink cross-connected to permit access to the entire UHS inventory, each division has the capacity to safely and orderly shutdown the reactor during normal and/or accident conditions completely independent of the other. Therefore, the Mechanical Draft Cooling Towers can perform their function with one division unavailable.

to NRC-23-0050 Page 5 As stated above, operation with one division of the Mechanical Draft Cooling Towers unavailable has been previously analyzed in the UFSAR and the maintenance activities planned for the MDCT Fan A and C pedestals are bound by this analysis.

Tornado / Missile Accident Analysis (UFSAR 3.5.1.3.2.2 & 9.2.5.2.2)

The fans are provided with a brake system to prevent overspeed from the design-basis tornado. The fan drive shaft is provided with a shield to protect it from tornado missiles.

The cooling tower structure is designed to withstand horizontal and vertical tornado missiles.

The cooling fan motor is enclosed in a concrete cubicle designed to repel both types of missiles, and the cooling tower gear hub and shaft are protected by missile shields.

Additionally, a study was performed to determine the probability that both cooling tower divisions can be rendered out-of-service by tornado- generated missiles entering the fan discharge stack. The result of this study found that this probability is very small and is conservatively estimated between 10-9 and 10-10 per year. Not withstanding this low probability, two spare sets of two RHR cooling tower fan blades and the necessary tools to install them are stored in the RHR complex building in a location protected from the tornado and tornado missiles. In the event that the cooling tower fan blades are damaged, the blades can be replaced, and the fan restored to an operating condition. Plant safe shutdown will not be precluded in the event of tornado missile damage to all four of the RHR cooling tower fans, including assuming a loss of offsite power and a single independent failure. The plant organization estimates that it would take six hours or less to replace a set of cooling tower fan blades. If no fans are available for six hours, reservoir temperature is calculated to rise to approximately 100 degrees F. All essential equipment cooled by the UHS is capable of performing its required safety functions at the higher reservoir temperature. One cooling tower fan can maintain hot standby and two cooling tower fans can achieve cold shutdown under these conditions.

In addition to missiles, miscellaneous debris can fall into the tower from the tornado. The debris would not damage the fan blades or other structural components of the towers. The debris would be removed while the blades are being replaced.

As stated above, the Mechanical Draft Cooling Tower system has been analyzed in the UFSAR for tornado and missile events. The maintenance activities planned for the MDCT Fan A and C pedestals are bound by this analysis.

Loss of Offsite Power (UFSAR 8.3.1 & 9.2.5)

The motors for the MDCT fans are connected to the ESF bus of the EDGs for a redundant power supply. In the event of a loss of normal power, the ESF electrical loads are automatically connected to the EDGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a Design Basis Accident (DBA) such as a Loss of Cooling Accident (LOCA).

to NRC-23-0050 Page 6 As stated above, the Mechanical Draft Cooling Tower fan motors have been analyzed for operation in case of a loss of offsite power. The maintenance activities planned for the MDCT Fan A and C pedestals are bound by this analysis.

In summary, the Mechanical Draft Cooling Towers are comprised of two redundant divisions, with each division individually capable of providing the necessary cooling of the Ultimate Heat Sink during all plant modes of operation and in accident conditions. The removal of one division of the Mechanical Draft Cooling Towers from service has been analyzed in the UFSAR and the maintenance activities planned for the MDCT Fan A and C pedestals are bound by this analysis.

3.1 Probabilistic Risk Assessment A quantitative and qualitative analyses of risk was performed to support the conclusion that the change in risk associated with the proposed one-time completion time increase due to one Division 1 RHRSW MDCT Fan unavailable is acceptable and is calculated consistent with NRC guidance documents.

The following table documents the Probabilistic Risk Assessment (PRA) evaluation conducted in support of the proposed one-time Technical Specifications (TS) change to extend the completion time from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to a total of 7 days associated with one Division 1 RHRSW MDCT being unavailable. The following acceptance guidelines from Regulatory Guide 1.177 (Reference 6.1) are applicable for evaluating the risk associated with the proposed change:

1. ICCDP of less than 1.0E-06 and ICLERP of less than 1.0E-07, or
2. ICCDP of less than 1.0E-05 and ICLERP of less than 1.0E-06 with effective compensatory measures implemented to reduce the sources of increased risk.

The results of quantification are presented in Table 1 below.

Table 1: Summary of Quantification Results and Risk Calculation Base Conditional CT ICCDP/

Delta

[/yr] Risk [/yr] [days] [yr] ICLERP

[/yr] I CDF 1.92E-(MDCT A 1.93E-06 1.95E-06 2.00E-08 7 3.83E-10 02 or C)

LERF 1.92E-(MDCT A 5.65E-07 5.76E-07 1.10E-08 7 2.11E-10 02 or C) to NRC-23-0050 Page 7 Note: Due to plant design configuration and equipment similarities between MDCT A and MDCT C, the quantification results for each fan were identical.

The ICCDP and ICLERP values were calculated using the following equations:

ICCDP = CDF * (7/365.25)

ICLERP = LERF * (7/365.25)

The results shown above demonstrate the impact on plant risk from implementing the one-time CT extension to 7 days is acceptable as the ICCDP and ICLERP satisfy the aforementioned acceptance guidelines listed in RG 1.177.

3.2 Compensatory Measures The following equipment protections will be in effect in accordance with MOP05-100 Protected Equipment [7] and ODE-20, Protected Equipment, [8] while the Division 1 RHRSW MDCT A (or C) Fan is unavailable:

1. Elective maintenance will not be performed on the following Division 2 Systems:

Emergency Equipment Cooling Water (EECW)

Emergency Equipment Service Water (EESW)

Ultimate Heat Sink (UHS)

Switchgear Emergency Diesel Generators (EDGs)

High Pressure Coolant Injection (HPCI)

Core Spray (CS)

Residual Heat Removal (RHR)

Standby Gas Treatment System (SGTS)

Control Center Heating, Ventilation, and Air Conditioning (CCHVAC)

Offsite Power

2. Elective maintenance will not be performed on the following non-divisional systems:
  • Hardened Containment Vent
3. Restricted access to all previously stated systems
4. Signage defining systems under protection both within and when entering protected area to NRC-23-0050 Page 8 All offsite power sources are currently operable and Offsite power is being supplied to both the 120 kV and 345 kV switchyards from the transmission network by five transmission lines.

Throughout the requested completion time, access to the switchyards will be controlled by the Main Control Room and will be restricted to only essential work, with no elective maintenance being performed. Shift Manager approval will be required to access the switchyards.

During the morning shift Midcontinent Independent System Operator (MISO) communications, Operations will verify no work affecting the 120kV or 345kV switchyards occurs. Weather conditions will be verified to be acceptable prior to authorizing work. Actions will be taken IAW MOP01-200, Severe Weather Guidelines, [9] in response to advanced notification of possible severe weather conditions.

The complete Risk Assessment is provided in full in Enclosure 4 of this submittal.

4.0 REGULATORY ANALYSIS

4.1 Applicable Regulatory Requirements/Criteria 4.1.1 10 CFR 50.36 10 CFR 50.36, Technical Specifications, defines the content required in licensee TS.

Specifically, 10 CFR 50.36(c)(2)(i) requires that the TS include limiting conditions for operation that are the lowest functional capability or performance levels of equipment required for safe operation of the facility. The EECW, EESW and UHS Systems satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii). The proposed changes will allow a one-time change to TS 3.7.2 Required Action A.1 to extend the Completion time. Based on this evaluation, the proposed extended Completion Time continues to support compliance to 10 CFR 50.36(c)(2).

4.1.2 10 CFR 50.91 10 CFR 50.91(a)(6) provides the requirements to be met to allow the NRC to perform expedited approval of a license amendment under exigent circumstances. As discussed in Section 3, Fermi is requesting exigent processing of this license amendment request, as a delay in approval of the proposed change could result in a potential unnecessary plant shutdown or need for enforcement discretion without a corresponding health and safety benefit. Accordingly, this license amendment request satisfies the criteria for the Commission to issue a license amendment under the exigent provisions of 10 CFR 50.91(a)(6).

4.1.3 General Design Criteria to NRC-23-0050 Page 9 Criterion 44 A system to transfer heat from structures, systems, and components important to safety to an ultimate heat sink shall be provided. The system safety function shall be to transfer the combined heat load of these structures, systems, and components under normal operating and accident conditions.

Suitable redundance in components and features, and suitable interconnection, leak detection, and isolation capabilities shall be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished assuming a single failure.

The proposed change to add an allowance for a longer Completion Time for TS 3.7.2, Required Action A.1, no impact on the permanent physical configuration, design, or function the EECW, EESW and UHS Systems. Even with the MDCT fans A and C isolated for the extended period, the remaining cooling water systems are still supported by functional equipment. Therefore, conformance to Criterion 44 is unaffected by the proposed changes.

The proposed change does not affect compliance with these regulations or guidance and will ensure that the lowest functional capabilities or performance levels of equipment required for safe operation are met.

4.2 Precedent This request is similar in nature to the following license amendments to extend completion times for Exigent Circumstances, as previously authorized by the NRC. These amendments also involve completion time extensions for cooling water systems required for plant shutdown. This proposed change does not alter the plant design, nor does it affect the information contained in the UFSAR.

Comanche Peak Nuclear Plant, Unit Nos. 1 and 2 - license amendment to extend the completion times for one station service water train inoperable and for one diesel generator inoperable from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 8 days. (Reference 6.2)

Prairie Island Nuclear Generating Plant, Units 1 and 2 - license amendment to extend completion time for inoperable cooling water system supply header from 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. (Reference 6.3)

Vogtle Electric Generating Plant, Unit 3, License Amendment to provide Technical Specification Exceptions for In-Containment Refueling Water Storage Tank Operability Prior to Initial Criticality. (Reference 6.4)

This Exigent License Amendment Request is also nearly identical to a recent Notice of Enforcement Discretion (NOED) approved by the NRC for DTE TS 3.7.2 to allow for repair of MDCT D.

to NRC-23-0050 Page 10 Notice of Enforcement Discretion (NOED) For Fermi Power Plant, Unit Two -

Technical Specification 3.7.2, Emergency Equipment Cooling Water (EECW) /

Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS) 4.3 No Significant Hazards Consideration DTE has evaluated whether or not a significant hazards consideration is involved with the proposed amendment for extending the Completion Time to repair of the Division I Mechanical Draft Cooling Tower (MDCT) A and C fan pedestals while online by focusing on the three standards set forth in 10 CFR 50.92, Issuance of Amendment, as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

DTE will use the compensatory measures and Fermi 2 Configuration Risk Management program requirements outlined Section 3.2 above and in Enclosure 4 during the duration of the proposed extension of the Completion Time for the MDCT fan pedestal repair. The risk impact of the proposed Completion Time is deemed acceptable and meets the requirements of RG 1.177.

Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed changes do not involve a change in design, configuration, or method of operation of the plant. The proposed changes will not alter the manner in which equipment is initiated, nor will the functional demands on credited equipment be changed. The proposed changes do not impact the interaction of any systems whose failure or malfunction can initiate an accident. There are no identified redundant components affected by these changes and thus, there are no new common cause failures or any existing common cause failures that are affected by extending the Completion Time. The proposed changes do not create any new failure modes.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

to NRC-23-0050 Page 11 The proposed changes do not alter the plant design, nor do they affect the assumptions contained in the safety analyses. Specifically, there are no changes being made to the MDCT fan design. The proposed changes have been evaluated and margins of safety ascribed to EECS availability and to plant risk have been determined to be not significantly reduced.

The risk impact of the proposed changes is acceptable to the compensatory measures and other requirements, as outlined in outlined Section 3.2 above and in Enclosure 4. As analyzed in the UFSAR, the loss of the Division I MDCT fans would not cause a significant reduction in safety because the MDCT system is redundant and can perform its function with one division unavailable.

The evaluation provided above shows that the proposed changes will not significantly increase the probability or the consequences of any accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated, or involve a significant reduction in the margin of safety. Therefore, the proposed changes meet the criteria of 10 CFR 50.92(c) and no significant hazard consideration is involved.

4.4 Conclusion In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would provide a one-time extension of the Completion Time to repair of the Division I MDCT A and C fan pedestals while online. The proposed amendment does not involve: (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 REFERENCES

6.1 U.S. Nuclear Regulatory Commission, Regulatory Guide 1.177, Revision 1, An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications, to NRC-23-0050 Page 12 May 2011 (ML100910008) 6.2 U.S. Nuclear Regulatory Commission, Letter to Mr. Ken J. Peters, Comanche Peak Nuclear Power Plant, Unit Nos. 1 And 2 - Issuance of Amendment Nos. 178 And 178 Regarding One-time Revision to Technical Specifications 3.7.8, Station Service Water System (SSWS), And 3.8.1, AC Sources - Operating, February 12, 2021.

(ML20324A627) 6.3 U.S. Nuclear Regulatory Commission, Letter to Mr. Christopher P. Domingos, Prairie Island Nuclear Generating Plant, Units 1 and 2 - Issuance of Amendment NOS. 237 and 225 Re: Inoperable Cooling Water Supply System Supply Header, November 23, 2021.

(ML21281A017) 6.4 U.S. Nuclear Regulatory Commission, Letter to Mr. Brian H. Whitley, Vogtle Electric Generating Plant, Unit 3 Issuance of Amendment: Technical Specification Exceptions for Incontainment Refueling Water Storage Tank Operability Prior to Initial Criticality (Exigent Circumstances) February 8, 2023 (ML23031A359) 6.5 U.S. Nuclear Regulatory Commission, Letter to Mr. Peter Dietrich, Notice of Enforcement Discretion (NOED) For Fermi Power Plant, Unit Two - Technical Specification 3.7.2, Emergency Equipment Cooling Water (EECW) / Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS),

July 26, 2023 (ML23206A127)

Enclosure 2 to NRC-23-0050 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Marked-up Pages of Existing Fermi 2 TS

EECW/EESW System and UHS 3.7.2 3.7 PLANT SYSTEMS 3.7.2 Emergency Equipment Cooling Water (EECW)/Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS)

LCO 3.7.2 Two EECW/EESW subsystems and UHS shall be OPERABLE.

APPLICABILITY: MODES 1, 2, and 3.

ACTIONS

------------- ---- ------------ -----NOTES ------- ----------- ------ - ---------

1. Enter applicable Conditions and Required Actions of LCO 3. 8 .1, "AC Sources-Operating," for diesel generator made inoperable by UHS.
2. Enter applicable Conditions and Required Actions of LCO 3.4.8, "Residual Heat Removal (RHR) Shutdown Cooling System-Hot Shutdown," for RHR shutdown cooling made inoperable by EECW/EESW or UHS.

CONDITION REQUIRED ACTION COMPLETION TIME tJ A. One reservoir A.1 Restore reservoir to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> inoperable. OPERABLE status.

B. One EECW/EESW B.1 Restore the EECW/EESW 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> subsystem inoperable subsystem to OPERABLE for reasons other than status.

Condition A.

(continued)

  • The 72-hour Completion Time is extended to 7 days for each of the Division I MDCT fan pedestals (A and C) to allow repair online during Cycle 22 and will expire at 2359 on November 19, 2023.

FERMI - UNIT 2 3.7-3 Amendment No. -+/-J4, 209

Enclosure 3 to NRC-23-0050 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Clean Pages of Fermi 2 TS with Changes Incorporated

EECW/EESW System and UHS 3.7.2 3.7 PLANT SYSTEMS 3.7.2 Emergency Equipment Cooling Water (EECW)/Emergency Equipment Service Water (EESW) System and Ultimate Heat Sink (UHS)

LCO 3.7.2 Two EECW/EESW subsystems and UHS shall be OPERABLE.

APPLICABILITY: MODES 1, 2, and 3.

ACTIONS

NOTES----------------------------------

1. Enter applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources-Operating," for diesel generator made inoperable by UHS.
2. Enter applicable Conditions and Required Actions of LCO 3.4.8, "Residual Heat Removal (RHR) Shutdown Cooling System-Hot Shutdown," for RHR shutdown cooling made inoperable by EECW/EESW or UHS.

CONDITION REQUIRED ACTION COMPLETION TIME A. One reservoir A.1 Restore reservoir to 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />s*

inoperable. OPERABLE status.

B. One EECW/EESW B.1 Restore the EECW/EESW 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> subsystem inoperable subsystem to OPERABLE for reasons other than status.

Condition A.

(continued)

  • The 72-hour Completion Time is extended to 7 days for each of the Division I MDCT fan pedestals (A and C) to allow repair online during Cycle 22 and will expire at 2359 on November 19, 2023.

FERMI - UNIT 2 3.7-3 Amendment No. 134, 209

Enclosure 4 to NRC-23-0050 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 DTE PRA Technical Evaluation TE-E11-23-052

TECHNICAL EVALUATION COVERSHEET TE Number: TE-E11-23-052 Revision: 0 Page 1 of 14 Initiating Document: Affected System/PIS number(s):

CR-2023-31630 E1156 / E1156C001A/C

Title:

Risk Evaluation for Exigent Technical Specification Regarding the Division 1 Residual Heat Removal Service Water Mechanical Draft Cooling Tower Fans Abstract:

The purpose of this technical evaluation is to assess the core damage and large early release risk associated with operating the plant with one Division 1 Residual Heat Removal Service Water (RHRSW) Mechanical Draft Cooling Tower (MDCT) Fan (E1156C001A or E1156C001C) unavailable due to planned maintenance. The evaluation provides the details of the quantitative and qualitative risk analyses used to support the proposed one-time Completion Time (CT) increase in accordance with the three-tiered approach outlined in Regulatory Guide (RG) 1.177, Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications.

Continued Conclusions/Restrictions:

The risk associated with operating the plant with one Division 1 RHRSW MDCT Fan unavailable for a period of 7 days was found to meet the thresholds of RG 1.177. To augment this evaluation, risk will be minimized during the proposed extended completion time by implementation of the compensatory measures described in this evaluation. These compensatory measures will be in effect prior to entry into the period of unavailability.

Continued Preparer (Print/Sign) Qualification: PSA-01/PSA-09 Kasi Rhodes / See Attached Email N/A (referDate:

to Step 6.2.3.5) 08/01/23 Reviewer (Print/Sign) Qualification: PSA-01/PSA-09 Mickey Koenemann / See Attached Email N/A (referDate:

to Step 6.2.6.8) 08/01/23 ITPR (Print/Sign) ~ N/A

/ Date:

Approver (Print/Sign)

Michael Lake / See Attached Email Date: 08/01/23 Human Performance and MES56 "Pre-Screen" MES56001 provided with Tech Evaluation* ~ , Full MES56 Risk Review: Required Optional

~

(*MES56001 not required to be attached to Tech Evaluation, only available for Supervisor review and to ensure it will be forwarded to HUDC in accordance with MES56)

Work Planner Acknowledgement (Print/Sign) ~ N/A

/ Date:

DTC: TDEVAL DSN: TE-E11-23-052 Rev: 0 File: 1803.01 IP: I ISFSI Related Yes No Date: 08/02/2023 DTC: TPMMES DSN: MES58001 Rev. 5 P1/1 IP: I File:1703.22 Issued: 1/12/2022

TE-E11-23-052 Revision 0 Page 2 of 14

1. PURPOSE The purpose of this technical evaluation is to assess the core damage and large early release risk associated with operating the plant with one Division 1 Residual Heat Removal Service Water (RHRSW) Mechanical Draft Cooling Tower (MDCT) Fan (E1156C001A or E1156C001C) unavailable due to planned maintenance. The evaluation provides the details of the quantitative and qualitative risk analyses used to support the proposed one-time Completion Time (CT) increase in accordance with the three-tiered approach outlined in Regulatory Guide (RG) 1.177, Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications. [1]
2. TIER 1A: ACCEPTABILITY OF THE PRA The Fermi 2 Probabilistic Risk Assessment (PRA) Model of Record, FermiV12 [2], was used to evaluate the impact of the proposed one-time CT extension on the risk metrics Delta Core Damage Frequency

(~CDF), Incremental Conditional Core Damage Probability (ICCDP), Delta Large Early Release Frequency (&ERF), and Incremental Conditional Large Early Release Probability (ICLERP).

The FermiV12 model is a component-level model which includes contributions from random failures, common-cause failures (CCFs), test downtime, and maintenance downtime. It has been peer reviewed against Regulatory Guide 1.200, Revision 2, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities [3]. All findings have been closed and non-Capability Category II supporting level requirements have been addressed. Resolutions have been incorporated into the FermiV12 model. Additional peer reviews have not been performed as there have been no PRA upgrades to the model.

To fully characterize the risk presented by this condition, an assessment is required to be performed on external event factors that could impact safety during the period of extended CT. Fermi 2 has developed an Other External Hazards (OEH) Screening Report [4] to determine the applicability of various external events to Fermi 2. The result of the screening report was that only internal flooding, internal fire and seismic hazards require detailed PRAs. Internal flooding is already included in the FermiV12 model.

A peer review of the Fermi 2 OEH Screening Report was conducted in May 2014 by industry peers under the auspices of the Boiling Water Reactor Owners Group (BWROG). The peer review report shows details of the Facts and Observations (F&Os) that were written as a result of this assessment. The report found that all supporting requirements meet Capability Category I/II/III of the ASME/ANS standard. All findings from this peer review have subsequently been closed. As only fire and seismic hazards were identified as necessary, no further external hazards need to be evaluated for this application.

This information demonstrates that the PRA is of sufficient quality and level of detail to support this evaluation.

3. TIER 1B: PRA INSIGHTS AND RESULTS Quantitative Risk Analysis:

This section details a quantitative risk evaluation performed for the purpose of comparing the ICCDP and ICLERP of operating the plant with one Division 1 RHRSW MDCT Fan (MDCT A or MDCT C) unavailable against the thresholds set forth in RG 1.177.

TE-E11-23-052 Revision 0 Page 3 of 14 One-Time Completion Time Extension Model Changes Because MDCT A and MDCT C will not be simultaneously unavailable, separate quantifications were performed for each fan. Only the Basic Events pertaining to the subject component were modified during the respective quantification. To quantify the conditional risk associated with MDCT A (or C) unavailable, the following changes were made to the baseline model to form the conditional risk model configuration:

1. The Basic Event ZMUAMDC1C001A (or ZMUAMDC1C001C), Mechanical Draft Cooling Tower Fan E1156C001A (or C) Unavailable Due to Maintenance was set to 1.0
2. Common cause failures associated with MDCT A (or C) were modified in accordance with RG 1.177 guidance. Modification details are discussed below.

Treatment of Common Cause Failures (CCFs)

Across two independent divisions of RHRSW, there are four MDCT Fans (Division 1: E1156C001A and E1156C001C, Division 2: E1156C001B and E1156C001D.) To comply with RG 1.177, the CCF contributions involving the MDCT A (or C) were modified to remove the subject component and to only include failures of the remaining components. The common cause component group (CCCG) was reduced by one to account for the subject components unavailability. This led to a slight increase in the CCF basic events probabilities. The adjustments made to the CCF basic events are shown in Table 1.

The Adjusted CCF Probability was determined from Equation 1 [5]:

Adjusted CCF Probability = (MT~ ak)

  • Prob0 Equation 1 Where MT is the Mission Time of the Subject Equipment is the Alpha Factor Model Parameter for the Corresponding CCF Combination C is the Component Grouping Coefficient Prob0 is the Independent Failure Probability Table 1: Summary of Adjusted Common Cause Failure Probabilities Original Adjusted Adjusted CCF Basic Event Description CCF CCF CCF Probability Philosophy Probability 3 of 4 MDCT Fans Fail to Start:

FCFSUHSXCC34_1 7.02E-07 2 of 3 2.77E-06 E1156C001A, E1156C001B, E1156C001C 3 of 4 MDCT Fans Fail to Start:

FCFSUHSXCC34_2 7.02E-07 2 of 3 2.77E-06 E1156C001A, E1156C001B, E1156C001D 3 of 4 MDCT Fans Fail to Start:

FCFSUHSXCC34_3 7.02E-07 2 of 3 2.77E-06 E1156C001A, E1156C001C, E1156C001D 3 of 4 MDCT Fans Fail to Start:

FCFSUHSXCC34_4 7.02E-07 2 of 3 2.77E-06 E1156C001B, E1156C001C, E1156C001D 4 of 4 MDCT Fans Fail to Start:

FCFSUHSXCC44_1 E1156C001A, E1156C001B, E1156C001C, 9.80E-07 3 of 3 2.38E-06 E1156C001D

TE-E11-23-052 Revision 0 Page 4 of 14 Original Adjusted Adjusted CCF Basic Event Description CCF CCF CCF Probability Philosophy Probability 3 of 4 MDCT Fans Experience a Time FCTSUHSXCC34_1 Sensitive Failure: 2.29E-07 2 of 3 6.85E-07 E1156C001A, E1156C001B, E1156C001C 3 of 4 MDCT Fans Experience a Time FCTSUHSXCC34_2 Sensitive Failure: 2.29E-07 2 of 3 6.85E-07 E1156C001A, E1156C001B, E1156C001D 3 of 4 MDCT Fans Experience a Time FCTSUHSXCC34_4 Sensitive Failure: 2.29E-07 2 of 3 6.85E-07 E1156C001B, E1156C001B, E1156C001D 3 of 4 MDCT Fans Experience a Time FCTSUHSXCC34_3 Sensitive Failure: 2.29E-07 2 of 3 6.85E-07 E1156C001A, E1156C001C, E1156C001D 4 of 4 MDCT Fans Experience a Time FCTSUHSXCC44_1 Sensitive Failure: E1156C001A, 4.27E-07 3 of 3 9.31E-07 E1156C001B, E1156C001C, E1156C001D While Table 1 summarizes all CCF Basic Events that involve MDCT A or C, separate quantifications were performed for each fan. Only CCF Basic Events containing the subject component were modified during the respective quantification. Because independent failure probabilities are already accounted for within the model, the probability of CCF Basic Events that delineate failure of 2 of 4 fans were not modified as the adjusted CCF philosophy would be 1 of 3 fans Additional Quantification Assumptions The following are additional relevant assumptions for the quantification parameters:

1. Calculations were performed with a 1.00E-12/yr truncation limit for CDF and a 5.00E-13/yr truncation limit for LERF.
2. FLEX equipment is not included in the FermiV12 Model of Record but can be credited to understand its impact to risk. The quantification results listed herein do not include credit for FLEX equipment.

Quantitative Risk Results ICCDP and ICLERP are determined from Equation 3 and Equation 5, respectively:

llCDF = CDFMDCT - CDFbase Equation 2 ICCDP = llCDF x CT Equation 3 llLERF = LERFMDCT - LERFbase Equation 4 ICLERP = llLERF x CT Equation 5 Where CDFMDCT is the Conditional CDF with the Subject Equipment (MDCT A or C) Assumed Unavailable CDFbase is the CDF with Nominal Expected Equipment Unavailabilities

TE-E11-23-052 Revision 0 Page 5 of 14 LERFMDCT is the Conditional LERF with the Subject Equipment (MDCT A or C) Assumed Unavailable LERFbase is the LERF with Nominal Expected Equipment Unavailabilities CT is the Total Duration of the Single Completion Time under Consideration Table 2 contains the results of the FermiV12 Internal Events Quantification, along with the resulting ICCDP and ICLERP. The conversion factor used to convert days to years is 365.25 days/year.

Table 2: Summary of Quantification Results and Risk Calculation Base Conditional Delta CT ICCDP/

[/yr] Risk [/yr] [/yr] [days] [yr] ICLERP CDF 1.93E-06 1.95E-06 2.00E-08 7 1.92E-02 3.83E-10 (MDCT A or C)

LERF 5.65E-07 5.76E-07 1.10E-08 7 1.92E-02 2.11E-10 (MDCT A or C)

Note: Due to plant design configuration and equipment similarities between MDCT A and MDCT C, the quantification results for each fan were identical.

Table 3 demonstrates the impact on plant risk from implementing the one-time CT extension to 7 days is acceptable as the ICCDP and ICLERP satisfy the acceptance guidelines listed in RG 1.177:

ICCDP::; 1.00E-06 and ICLERP::; 1.00E-07.

Qualitative Risk Analysis:

Unscreened Fire Areas From the Fermi 2 Individual Plant Examination for External Events (IPEEE) [6], which employed a Fire Induced Vulnerability Evaluation (FIVE) methodology, six unscreened fire areas were shown to be risk significant. These are shown below in a reproduction of Table 4-14 of the IPEEE.

Unscreened Fire Areas Fire Area Description RB06 Reactor Building 2nd Floor 03AB Relay Room 04ABN Division 1 Switchgear Room 09AB Control Room 11ABE Division 1 Portion Miscellaneous Room 12AB Division 2 Switchgear Room Each of the compartments is discussed below in the context of the current plant configuration to develop risk-informed insights for fire hazards. The goal of this analysis is to evaluate fires that preferentially impact Division 1 RHR decay heat removal and rely upon the Division 2 counterparts for achieving safe shutdown.

TE-E11-23-052 Revision 0 Page 6 of 14 RB06:

From Section 4.3.1.4.5 of the IPEEE, dominant fires in this area lead to core damage due to their impact on bus 72CF, which impacts both divisions of LPCI. Core damage sequences for these fires are dominated by random failure of the torus cooling injection valves. In addition, some scenarios in this fire area can result in failure of Division 2 RHR and the Torus Hardened Vent. As these dominant fires can affect the ability of Division 2 RHR to remove decay heat, fire risk management actions will be implemented in this area.

03AB:

Section 4.3.1.4.1 of the IPEEE describes the dominant core damage scenarios for fires in the relay room.

The dominant fires in this area cause depressurization and loss of one division of RHR for heat removal.

In addition, some scenarios in this fire area can result in failure of Division 2 RHR and the Torus Hardened Vent. As these dominant fires can affect the ability of Division 2 RHR to remove decay heat, fire risk management actions will be implemented in this area.

04ABN:

Section 4.3.1.4.2 of the IPEEE states that dominant core damage contributors in the Division 1 Switchgear Room involve severe degradation of Division 1 decay heat removal capability. It is assumed only Division 2 of RHR is available for decay heat removal. As these dominant fires do not impact the ability of Division 2 RHR to remove decay heat, no fire risk management actions are required for this area.

09AB:

From Section 4.3.1.4.3 of the IPEEE, the most severe fire in the control room is a fire in panel H11P602, which defeats all Division 2 ESF systems and results in core damage due to random failure of standby feedwater and Division 1 low pressure injection systems. Dominant fires in this zone impact the ability to remove decay heat using Division 2 RHR, so fire risk management actions will be implemented in this area.

11ABE:

From Section 4.3.1.4.4 of the IPEEE, the most severe fires mentioned in the DC MCC area are those that affect Division 1 DC. As these dominant fires do not impact the ability of Division 2 RHR to remove decay heat, no fire risk management actions are required for this area.

12AB:

This fire area is the divisional opposite of 04ABN. Because dominant fires in this zone can impact the ability to remove decay heat using Division 2 RHR, fire risk management actions will be implemented in this area.

Discussion of Risk Insights from Seismic Hazards Seismic events are those that are likely to lead to core damage by causing a loss of offsite power. As such, existing measures to protect Division 2 EDGs and Division 2 RHR are considered prudent measures to reduce the risk of seismic events during the period of proposed one-time CT extension.

4. TIER 2: POTENTIALLY HIGH RISK CONFIGURATIONS Mitigating Design Features The following are Fermi 2 specific design features that enhance Fermi 2s ability to successfully mitigate most initiating events.

TE-E11-23-052 Revision 0 Page 7 of 14

1. Fermi 2 has two physically and electrically independent sources of Offsite power (120 kV and 345 kV lines). These offer the site greater electrical redundancy.
2. Fermi 2 has two Emergency Diesel Generators (EDGs) per Division.
3. Fermi 2 has four CTGs, one of which is self black-start capable. The other three are capable of black start with the assistance of a black start diesel generator. The CTGs normally provide power to Division 1 loads, and the PRA model credits operator action to crosstie to Division 2.
4. Fermi 2 has a high pressure inventory makeup system Standby Feedwater (SBFW), in addition to High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC). SBFW is a motor driven system which can also be utilized at low reactor pressures and can be powered by any of the four CTGs.

Dominant CDF Contributors The most dominant CDF initiating event contributors that increased with unavailability of one Division 1 RHRSW MDCT Fan are listed in Table 3.

Table 3: Dominant CDF Initiating Event Contributor Increases Base Conditional Description Delta Contribution Contribution Loss of Bus #301 7.78E-08 8.42E-08 6.48E-09 Loss of Bus #101 1.34E-07 1.39E-07 5.51E-09 Total Loss of Offsite Power (LOSP) 2.91E-07 2.94E-07 3.39E-09 Partial LOSP for Division 1 2.48E-08 2.54E-08 5.46E-10 There were no initiating events whose contribution to CDF decreased due to the unavailability of one Division 1 RHRSW MDCT Fan.

LERF Contributors The most dominant LERF initiating event contributors present with unavailability of one Division 1 RHRSW MDCT Fan are listed in Table 4.

Table 4: Dominant LERF Initiating Event Contributor Increases Base Conditional Description Delta Contribution Contribution Loss of Bus #301 3.41E-08 3.88E-08 4.73E-09 Loss of Bus #101 5.36E-08 5.75E-08 3.82E-09 Total LOSP 1.70E-08 1.82E-08 1.27E-09 Loss of Turbine Building Closed 1.55E-09 1.74E-09 1.98E-10 Cooling Water (TBCCW)

Partial LOSP for Division 1 7.67E-09 7.85E-09 1.84E-10

TE-E11-23-052 Revision 0 Page 8 of 14 There were no initiating events whose contribution to LERF decreased due to the unavailability of one Division 1 RHRSW MDCT Fan.

Evaluation of Contributors The dominant risk contributors found in the increased initiators and in the cutsets containing one Division 1 RHRSW MDCT Fan are loss of Division 2 power or equipment that leads to a loss of the Primary Containment or the ability to vent Primary Containment. The compensatory measures listed below have been deemed adequate to address the risk contributors listed in Table 3 and Table 4.

Compensatory Measures The following equipment protections will be in effect in accordance with MOP05-100 Protected Equipment [7] and ODE-20, Protected Equipment, [8] while the Division 1 RHRSW MDCT A (or C)

Fan is unavailable:

1. Elective maintenance will not be performed on the following Division 2 Systems:
  • Switchgear
  • Control Center Heating, Ventilation, and Air Conditioning (CCHVAC)
  • Offsite Power
2. Elective maintenance will not be performed on the following non-divisional systems:
  • Hardened Containment Vent
3. Restricted access to all previously stated systems
4. Signage defining systems under protection both within and when entering protected area All offsite power sources are currently operable and Offsite power is being supplied to both the 120 kV and 345 kV switchyards from the transmission network by five transmission lines. Throughout the requested completion time, access to the switchyards will be controlled by the Main Control Room and will be restricted to only essential work, with no elective maintenance being performed. Shift Manager approval will be required to access the switchyards.

During the morning shiftly Midcontinent Independent System Operator (MISO) communications, Operations will verify no work affecting the 120kV or 345kV switchyards occurs. Weather conditions will be verified to be acceptable prior to authorizing work. Actions will be taken IAW MOP01-200, Severe Weather Guidelines, [9] in response to advanced notification of possible severe weather conditions.

TE-E11-23-052 Revision 0 Page 9 of 14 Fire Risk Management Actions For compartments RB06, 03AB, 09AB, and 12AB, the following risk management actions will be taken during the period of requested completion time. These actions reduce the probability of a consequential fire in the risk significant areas of the plant.

  • Prohibit hot work or limit with adequate compensatory measures per ODE-20
  • Confirm availability of detection and suppression systems
  • Inspect area for fire source degradation
  • Minimize electrical switching at panels as applicable or establish compensatory measures per ODE-20 Uncertainty Analysis:

The Fermi 2 Uncertainty Analysis Notebook (EF2-PRA-019) [10] provides analysis of key assumptions and uncertainties in the PRA model. The disposition of each key assumption is listed in Table 5.

Table 5: Review of Key Assumptions and Uncertainties Source in Description of Uncertainty Applicability Disposition EF2-PRA-019 Table 2-1 #1 The approach used for LOSP While LOSP is a dominant risk contributor, frequency and failure to recover the estimates are conservative, and therefore, is considered a good practice, not a key source of uncertainty (SOU) for but not yet an industry standard this application.

approach. The LOSP estimates are judged to be conservative for Fermi 2.

Table 2-1 #8 (4) Post-containment failure These systems are not affected by this one-injection via SBFW, portable time CT extension. Due to the negligible risk pumps, RHRSW, and CRD increase in the evaluation, this SOU is not injection is identified as a considered key for this application.

candidate source of model uncertainty.

Table 2-1 #8 (4) No credit is given for ECCS, Given that RHRSW is not credited as a CRD, local connections, and Decay Heat Removal method following a RHRSW after soft soft containment venting scenario, the containment venting (venting of unavailability of MDCT A or C would not containment via non-hardened impact risk. Therefore, this SOU is not standby gas treatment piping. considered key for this application.

This is due to the adverse environmental conditions in the reactor building that might be expected if the soft vent ductwork fails.

TE-E11-23-052 Revision 0 Page 10 of 14 Table 5: Review of Key Assumptions and Uncertainties Source in Description of Uncertainty Applicability Disposition EF2-PRA-019 Table 2-1 #14 Some plant systems are credited Despite the potentially higher failure rates of to operate beyond their design some systems, due to the negligible risk basis envelope. Removal of some increase in this evaluation, it is expected the of this credit may result in higher risk would remain acceptable. Therefore, failure rates for some systems. this SOU is not considered key for this application.

Table 2-1 #16 Flood initiator frequencies are Since the risk increase due to this one time based on plant-specific estimates CT extension is negligible, including of pipe lengths and generic flood flooding, changing flooding frequencies that frequencies. The approach is are already a good practice would not have a considered an industry good major impact on flooding CDF or LERF.

practice but is not a consensus Therefore, this SOU is not considered key model approach. for this application.

Table 2-1 #22 The approach for ISLOCA Since the risk increase due to this one time frequency determination is CT extension is negligible, changing considered an industry good ISLOCA frequencies that are already a good practice but is not yet considered practice would not have a major impact on a consensus model approach. CDF or LERF. Therefore, this SOU is not considered key for this application.

Table 3-1 #2 Digital feedwater control failure The Feedwater System is not affected by this probabilities are identified as a one-time CT extension. Due to the very candidate source of model small risk increase in the evaluation, this uncertainty. SOU is not considered key for this application.

Table 3-1 #7 The B.5.b, diesel and electric fire Given the large degree of redundancy in pumps are not credited for low-pressure injection at Fermi 2, adding injection. credit for firewater injection is expected to have a small reduction in overall risk.

Therefore, this SOU is not considered key for this application.

Table 3-1 #9 The conditional probability of Since the risk increase due to this one time CTGs to fail in a weather-related CT extension is negligible, and the LOSP loss of offsite power is uncertain. sequences are conservatively modeled, the uncertainty related to CTG failure probability is not considered key for this application.

The key sources of uncertainty None of these SOUs are directly related to from these tables were reviewed. the unavailable components They are applicable to the Level (E1156C001A/C) of this analysis. Further, 2 PRA and generally pertain to any unrecognized containment failure modes severe accident accounting and would be accounted for as all loss of Decay Table 4-1, phenomenology. Heat Removal sequences are conservatively Table 5-1 modeled as LERF [11]. Therefore, it is unlikely that any of these SOUs would have an appreciable positive effect on LERF.

Therefore, these SOUs are not considered key for this application.

TE-E11-23-052 Revision 0 Page 11 of 14

5. TIER 3: CONFIGURATION RISK MANAGEMENT PROGRAM While in the proposed extended CT, overall plant risk will be managed by the existing Configuration Risk Management Program (CRMP) [12]. This program evaluates increases in risk posed by potential combinations of equipment out-of-service and potential increases in initiating event frequency and requires that risk management actions be implemented as appropriate for a given plant configuration. Maintenance and testing during the allowed completion time extension will be scheduled for Fermi 2 as warranted to minimize aggregate risk. This will specifically include work performed on safety significant systems and their applicable support systems. Emergent Conditions will be evaluated by operations under the CRMP.

No quantitative credit was taken in the evaluation for the implementation of the CRMP nor the aforementioned compensatory measures.

6. CONCLUSION The risk associated with operating the plant with one Division 1 RHRSW MDCT Fan unavailable for a period of 7 days was found to meet the thresholds of RG 1.177. To augment this evaluation, risk will be minimized during the proposed extended completion time by implementation of the compensatory measures described in this evaluation. These compensatory measures will be in effect prior to entry into the period of unavailability.
7. REFERENCES

[1] U.S. Nuclear Regulatory Commission, Regulatory Guide 1.177, "Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications", Revision 2, 2021.

[2] TMSA-21-0001, Documentation of the Release of PSA Model FermiV12", 2021.

[3] U.S. Nuclear Regulatory Commission, Regulatory Guide 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities",

Revision 2, 2009.

[4] EF2-PRA-023, "PRA System Notebook Other External Hazards Screening Report", Revision 1, 2016.

[5] EF2-PRA-010, "Fermi 2 Nuclear Power Station PRA Component Data Notebook, VOL 2", Revision 4, 2021.

[6] TMSA-10-0010, "Fermi 2 Individual Plant Examination for External Events (IPEEE)", 2010.

[7] MOP05-100 "Protected Equipment" Revision 2C, 2018.

[8] ODE-20, "Protected Equipment" Revision 29, 2023.

[9] MOP01-200, "Severe Weather Guidelines" Revision 4, 2021.

[10] EF2-PRA-019, "Uncertainty Analysis Notebook", Revision 5, 2021.

[11] EF2-PRA-014, "Fermi 2 Nuclear Power Station PRA Level 2 Notebook", Revision 3, 2021.

[12] MMR12 "Equipment Out of Service Risk Management", Revision 20A, 2019.

TE-E11-23-052 Revision 0 Kasi Rhodes Page 12 of 14 From: Kasi Rhodes Sent: Tuesday, August 1, 2023 11:10 AM To: Kasi Rhodes Cc: Mickey Koenemann; Michael Lake

Subject:

TE-E11-23-052 Preparer Signature This email serves as my approval to sign the following documents electronically as PREPARER for the following document and should be attached for vaulting purposes:

DSN Revision DTC Date TE-E11-23-052 0 TDEVAL 08/01/2023 I have verified my qualification to PSA-09 as required per PSA-Wl-006 for this task prior to sending this email.

Thank you, KASI RHODES M R UL E & P S A E NG I NE E R Enrico Fermi Atomic Power Plant l Newport, MI 734.586.4165 l kassandra.rhodes@dteenergy.com This communication may contain privileged or confidential information protected by legal rules. It is solely for the use of t he intended recipient named above. Any review, dissemination, distribution, forwarding, or copying of this communication by someone other than the intended recipient, or the employee responsible for delivering this communication to the intended recipient, is prohibited. If you have received this communication in error, please immediately notify us by phone or reply to the sender via email, then destroy the original message. Thank you.

1

TE-E11-23-052 Revision 0 Kasi Rhodes Page 13 of 14 From: Mickey Koenemann Sent: Tuesday, August 1, 2023 11:15 AM To: Kasi Rhodes Cc: Michael Lake

Subject:

TE-E11-23-052 Reviewer Signature This email serves as my approval to sign the following documents electronically as REVIEWER for the following document and should be attached for vaulting purposes:

DSN Revision DTC Date TE-E11-23-052 0 TDEVAL 08/01/2023 I have verified my qualification to PSA-09 as required by PSA-WI-006 for this task prior to sending this email.

Mickey Koenemann PSA Technical Expert - Fermi 2 734-586-1885 Michael.koenemann@dteenergy.com 1

TE-E11-23-052 Revision 0 Kasi Rhodes Page 14 of 14 From: Michael Lake Sent: Tuesday, August 1, 2023 12:33 PM To: Kasi Rhodes

Subject:

FW: TE-E11-23-052 Approver Signature This email serves as my approval to sign the following documents electronically as APPROVER for the following document and should be attached for vaulting purposes:

DSN Revision DTC Date TE-E11-23-052 0 TDEVAL 08/01/2023 1

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