ML25290A335

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Emergency License Amendment Request - One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions
ML25290A335
Person / Time
Site: Calvert Cliffs 
Issue date: 10/17/2025
From: Para W
Constellation Energy Generation, Constellation Energy Group
To:
Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML25290A334 List:
References
Download: ML25290A335 (1)


Text

200 Energy Way Kennett Square, PA 19348 www.constellation.com Proprietary Information - Withhold from Public Disclosure Under 10 CFR 2.390 contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachment 6, this document is decontrolled.

10 CFR 50.90 10 CFR 50.91(a)(5)

October 17, 2025 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318

SUBJECT:

Emergency License Amendment Request - One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Pursuant to 10 CFR 50.90, Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), requests Nuclear Regulatory Commission (NRC) approval for a new additional condition of the Renewed Facility Operating License (FOL) No. DPR-69 for Calvert Cliffs Nuclear Power Plant (CCNPP), Unit 2. This approval is being requested on an emergency basis pursuant to 10 CFR 50.91(a)(5).

The proposed change is a swap of the assigned group for 2 Control Element Assemblies (CEAs) during the current operating cycle, Calvert Cliffs Unit 2 Cycle 26 (CC2C26). This amendment is necessary due to a degraded Control Element Drive Mechanism (CEDM) upper gripper coil (UGC) that is inhibiting operator demanded motion for CEA 36. The degraded CEDM does not impact the ability for CEA 36 to fully insert when tripped.

The proposed deterministic change request will remain in effect until Unit 2 next enters MODES 3, 4, or 5. This will occur no later than the end of CC2C26, currently planned for February 2027.

provides an evaluation of the proposed change. Attachments 2 and 3 provide marked-up and clean pages, respectively, of the FOL Appendix C, Additional Conditions, indicating the proposed change.

contains information proprietary to Framatome. The affidavit, provided in, sets forth the basis on which Framatomes information may be withheld from public disclosure by the NRC and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR 2.390, "Public inspections, exemptions, requests for withholding." Accordingly, it is respectfully requested that the information that is proprietary to Framatome be withheld from public disclosure in accordance with 10 CFR 2.390.

Attachments 5 and 6 provide non-proprietary and proprietary copies, respectively, of the Framatome safety analysis report supporting the proposed change.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Docket No. 50-318 October 17, 2025 Page 2 contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachment 6, this document is decontrolled.

CEG requests approval of the proposed change as soon as possible based on emergency circumstances at CCNPP in accordance with the provisions of 10 CFR 50.91(a)(5) but no later than November 3, 2025. This change is necessary to support a planned power reduction to repair a damaged Communication Control Measuring (CCM) card for the Unit 2 Main Generator Automatic Voltage Regulator (AVR). The proposed change, if approved, will be implemented within 14 days of issuance.

The proposed change has been approved by the CCNPP Plant Operations Review Committee in accordance with the requirements of the CEG Quality Assurance Program.

There are no regulatory commitments contained in this submittal.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b), CEG is notifying the State of Maryland of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

Should you have any questions concerning this submittal, please contact Adam Donell at (267) 533-5156.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 17th day of October 2025.

Respectfully, Wendi Para Sr. Manager - Licensing Constellation Energy Generation, LLC Attachments:

1. Evaluation of Proposed Change 2.

Proposed Facility Operating License, Appendix C, Additional Conditions Page (Markup) 3.

Proposed Facility Operating License, Appendix C, Additional Conditions Page (Clean) 4.

Affidavit from Framatome Supporting the Withholding of Information in from Public Disclosure 5.

Framatome Report ANP-4173NP Rev. 0, Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report (Non-Proprietary) 6.

Framatome Report ANP-4173P Rev. 0, Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report (Proprietary) cc:

USNRC Region I, Regional Administrator USNRC Senior Resident Inspector, Calvert Cliffs Nuclear Power Plant USNRC Project Manager, NRR - Calvert Cliffs Nuclear Power Plant Z. Barthel, State of Maryland

ATTACHMENT 1 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 EVALUATION OF PROPOSED CHANGE

Subject:

Emergency License Amendment Request - One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION 2.1 Control Element Assembly Description 2.2 Control Element Drive System Description 2.3 Current Facility Operating License and Technical Specification Requirements 2.4 Emergency Condition 2.5 Proposed Change 2.6 Additional Work Required to Change Control Element Assembly Group Definitions

3.0 TECHNICAL EVALUATION

3.1 Safety Analysis 3.2 Cycle-specific Restrictions

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 No Significant Hazards Consideration 4.4 Conclusions

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 1 of 18 1.0

SUMMARY

DESCRIPTION Pursuant to 10 CFR 50.90, Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), requests Nuclear Regulatory Commission (NRC) approval for a new additional condition of the Renewed Facility Operating License (FOL) No. DPR-69 for Calvert Cliffs Nuclear Power Plant (CCNPP), Unit 2. This approval is being requested on an emergency basis pursuant to 10 CFR 50.91(a)(5).

The proposed change is a swap of the assigned group for 2 Control Element Assemblies (CEAs) during the current operating cycle, Calvert Cliffs Unit 2 Cycle 26 (CC2C26). This amendment is necessary due to a degraded Control Element Drive Mechanism (CEDM) upper gripper coil (UGC) that is inhibiting operator demanded motion for CEA 36. The degraded CEDM does not impact the ability for CEA 36 to fully insert when tripped.

2.0 DETAILED DESCRIPTION 2.1 Control Element Assembly Description 2.1.1 General System Description The reactor core control element configuration consists of 37 single CEAs and 20 dual CEAs.

Each dual CEA consists of two single CEAs connected to a single extension shaft and carried by a single CEDM. Considering the 20 dual CEAs as 40 single CEAs gives an overall equivalent of 77 single CEAs in the core.

During normal operation all of the CEAs are in the fully withdrawn position (all rods out).

Operator demanded CEA movement is accomplished via a digital control system that sequences CEDM coils to change or hold CEA position. Mechanical reactivity control is achieved by vertically maneuvering the positions of the CEA groups by the magnetic jack CEDMs. CEAs are moved in groups and with a defined overlap in order to satisfy the requirements of shutdown margin and provide a more uniform impact on reactivity. For conditions that require a rapid shutdown of the reactor, the Reactor Protection System (RPS) opens reactor trip breakers to deenergize CEDM holding coils, allowing the CEAs to drop into the core.

2.1.2 CEA Group Description The CEAs are designated as either regulating CEAs or shutdown CEAs. The regulating CEAs are divided into five groups (1 through 5). The shutdown CEAs are divided into three groups (A, B, and C). The locations of all the CEAs in one of four symmetrical core quadrants, and their assigned original group, are shown in the figure below.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 2 of 18 The Power Dependent Insertion Limits (PDILs) specify the maximum permitted CEA insertion.

The PDIL curve for the current cycle of Unit 2 is in the Core Operating Limits Report (COLR)

(Reference 6.2). The PDIL curve illustrates the regulating CEA groups insertion order (5-4-3 1) with overlap between successive groups. The typical CEA withdrawal procedure is as follows:

a. With the reactor subcritical, shutdown group A is fully withdrawn, followed by shutdown group B and then shutdown group C.
b. Withdrawal of regulating CEAs commences starting with regulating group No. 1. CEA withdrawal continues with the prescribed overlap of regulating groups 2 through 5.

All CEAs are inserted for cold shutdown conditions and are typically fully withdrawn during full power steady state operation. All CEAs within a particular group are designated to be withdrawn or inserted nearly simultaneously. The allowable CEA misalignment within any CEA group is specified in Technical Specifications and intentional misalignment of CEAs within a group for the purpose of power shaping is not allowed.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 3 of 18 2.2 Control Element Drive System Description 2.2.1 General System Description Control element assembly movement is driven by the CEDMs. The Digital Control Element Drive Control System (DCEDCS) transmits signals from the Control Element Drive System (CEDS) control panel to the Mag-Jack Pulse Generators & Monitor (M-PGM) Modules, which develop the current pulses for magnetic jack operation.

The upper and lower CEA group stops for the regulating and shutdown groups are provided by the CEA supervisory function to prevent the reactor from reaching undesirable conditions. The DCEDCS contains design features that ensure the following actions:

a. Insertion of the regulating CEAs within a predetermined permitted range before the shutdown groups are inserted;
b. Simultaneous withdrawal of no more than two groups of CEAs;
c. Proper sequential withdrawal of CEAs; and,
d. Withdrawal of the shutdown CEAs to a predetermined permitted range before the regulating groups are withdrawn.

The shutdown CEAs may be moved either individually or in defined groups. Movement is controlled manually or via a Semi-Automatic (SA) option, where a destination CEA position can be selected, and hands-off movement of the CEAs can be initiated. Movement of more than one shutdown group at any time is not possible. The shutdown CEAs must be withdrawn to within a predetermined permissible range of the upper limit before regulating group withdrawal is possible. A limit prevents group insertion of shutdown CEAs unless all regulating CEAs are within a predetermined permissible range of the lower limit.

The regulating CEAs may be moved in manual group, individual or sequential modes.

Movement is controlled manually or via a SA option, where a destination CEA position can be selected, and hands-off movement of the CEAs can be initiated. Sequential group movement functions such that when the moving group reaches a programmed low (high) position, the next group begins inserting (withdrawing); the initial group stops upon reaching its lower (upper) limit.

This procedure, applied successively to all regulating groups, allows a smooth and continuous rate-of-change of reactivity.

2.2.2 CEDM Description The CEDMs are of the magnetic jack-type drive. Each CEDM is capable of withdrawing, inserting, holding, or tripping the CEA from any point within its operating range. The CEDM drives the CEA and indicates the position of the CEA with respect to the core. For conditions that require a rapid shutdown of the reactor, the CEDM coils are deenergized by the RPS, allowing the CEA to drop into the core by gravity. The reactivity is reduced during such a drop at a rate sufficient to control the core under any operating transient or accident condition.

The magnetic jack motor assembly fits into the CEDM pressure tube housing within the reactor coolant system (RCS) pressure boundary. This integral unit carries the motor tube, lift and hold pawls, and magnets. DC electrical coils positioned externally around the CEDM housing supply the drive power. The CEA lifting operation consists of a series of magnetically-operated step

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 4 of 18 movements. Two sets of mechanical latches engage a notched drive shaft. The magnetic force is obtained from large DC magnet coils mounted on the outside of the motor tube. Power for the electromagnets is obtained from an M-PGM. The M-PGM actuates the stepping cycle and positions the CEA by energizing the various coils in a forward or reverse stepping sequence or holds the CEA stationary by energizing one coil at a reduced current while all other coils are deenergized. The CEAs are tripped upon interruption of electrical power to all coils.

2.3 Current Facility Operating License and Technical Specification Requirements The CCNPP Unit 2 FOL Appendix C, Additional Conditions, includes a requirement for NRC review and approval of any changes to COLR Figures 3.1.6, 3.2.3, and 3.2.5. COLR Figure 3.1.6 specifies CEA group insertion limits vs. the fraction of rated thermal power (RTP) and was developed based on CEA group assignments shown in Section 2.1.2 above. This license condition was implemented per Unit 2 Amendment No. 273 License Condition 4 (Reference 6.1).

Additionally, the Bases for TS 3.1.4, Control Element Assembly (CEA) Alignment, state that the CEAs are arranged into groups that are radially symmetric and that movement of the CEA groups do not introduce radial asymmetries in the core power distribution. CEA inoperability or misalignment may cause increased power peaking, due to the asymmetric reactivity distribution and a reduction in the total available CEA worth for reactor shutdown. Therefore, CEA alignment and operability are related to core operation in design power peaking limits and the core design requirement of a minimum shutdown margin (SDM).

2.4 Emergency Condition Following startup of CC2C26, in April 2025, the upper gripper coil for CEA 36 (core location L-19, regulating group 5) was determined to be failed, inhibiting demanded CEA 36 motion. CEA 36 is fully withdrawn and within 7.5 inches of other regulating group 5 CEAs. CEA 36 remains OPERABLE although it is not capable of moving by operator demand to control power. The issue does not impact the ability for CEA 36 to fully insert when tripped.

Because CEA 36 is in regulating group 5 (first group inserted to lower power), group 5 insertion is not possible due to TS 3.1.4 alignment requirements. CC2C26 is currently being operated with all CEAs fully withdrawn and only boration/dilution available to make reactivity changes.

Using only boration/dilution is sufficient for reactor control early in the fuel cycle and for reactivity control to maintain full power operation. However, as the Hot Full Power (HFP)

Moderator Temperature Coefficient (MTC) becomes more negative through the fuel cycle, CEA motion availability is needed for optimal plant control, Axial Shape Index (ASI) control, and for the TS required 2/3 cycle MTC measurement due in June 2026.

Additionally, it was recently identified that Communication Control Measuring (CCM) card #2 for the Unit 2 Main Generator Automatic Voltage Regulator (AVR) needs to be replaced, as the #1 card is a single point vulnerability in the current condition. A power reduction to approximately 14% RTP will be required to replace the damaged CCM card. Modeling has shown that with boron as the only means for reactivity control, there is reduced margin to ASI limits. Margin is further reduced as the cycle progresses and inadequate margin is available after approximately 14,000 megawatt-days per metric ton of uranium (MWd/MTU) burnup. The current cycle exposure is approximately 6,000 MWd/MTU. At the current cycle exposure, the maneuver is

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 5 of 18 feasible, with reduced margin, from a power distribution standpoint. However, without control rods available to control reactivity, power cannot be ramped quickly enough to reliably traverse an "AVOID OPERATION" region in less than ten minutes at applicable condenser back pressure levels to avoid a turbine and reactor trip. This maneuver is planned to commence on November 21, 2025, to minimize the time the single point vulnerability exists.

The proposed one-time license amendment is required to prevent the unnecessary shutdown of CCNPP, Unit 2 and is emergent due to the unforeseen challenges with both the degraded CEDM UGC for CEA 36 and the damaged AVR CCM card. Further, NRC approval is needed sooner than can be provided under exigent circumstances, and this license amendment request is timely considering the unplanned nature of the issues and time required to develop the technical justification supporting the proposed change. Therefore, CEG has determined that emergency circumstances exist and that CCNPP did not knowingly cause the emergent situation. Further, CEG affirms a best effort has been made for a timely license amendment application. Accordingly, CEG requests an expedited review of the proposed emergency license amendment in accordance with the provisions of 10 CFR 50.91(a)(5) to avoid the unnecessary reduction of margin and potential shutdown of CCNPP, Unit 2 during the planned AVR CCM card repair downpower.

2.5 Proposed Change For Unit 2 Cycle 26 only, CEG is proposing that CEA 36 (core location L-19) and CEA 60 (core location J-20) group assignments be swapped such that CEA 36 is part of regulating group 1 and CEA 60 is part of regulating group 5. This will allow operator demanded movement of regulating groups to control core reactivity.

The CCNPP Unit 2 FOL Appendix C, Additional Conditions, includes a requirement for NRC review and approval of any changes to COLR Figures 3.1.6, 3.2.3, and 3.2.5 (Reference 6.1, License Condition 4). Although COLR Figures 3.1.6, 3.2.3, and 3.2.5 are not expected to be updated as part of the proposed change, CEA group assignments impact the analyses that resulted in the need for this additional condition, specifically for COLR Figure 3.1.6. Therefore, Constellation is seeking approval for the proposed CEA group change consistent with this license condition.

Based on the analyses documented in Section 3.1, a new CCNPP Unit 2 FOL Appendix C, additional condition is proposed to be updated as shown in Attachments 2 (markup) and 3 (clean) as follows:

For Unit 2 Cycle 26 only:

CEA 36 (core location L-19) and CEA 60 (core location J-20) group assignments may be swapped such that CEA 36 is part of regulating group 1 and CEA 60 is part of regulating group

5. If CEA 36 and CEA 60 group assignments are swapped and core thermal power is lowered to less than or equal to 1% of rated thermal power, Unit 2 shall continue to MODE 3. If CEA 36 and CEA 60 group assignments are swapped and Unit 2 enters MODE 3, 4, or 5, the original CEA group assignments shall be restored prior to entering MODE 2. NRC prior review and approval is not required to restore the original CEA group assignments.

Aside from the FOL Appendix C additional condition described, the Facility Operating License

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 6 of 18 and Technical Specifications are unaffected by this change.

Other CCNPP Unit 2 FOL Appendix C, Additional Conditions were reviewed. No other additional conditions are impacted by the proposed change.

Surveillance Requirements (SRs) associated with this proposed change were reviewed. Any impacts due to the proposed change will be managed by the Surveillance Frequency Control Program.

The proposed change will result in radially asymmetric CEA groups for regulating groups 1 and

5. The impact of these asymmetric CEA groups on the core power distribution, power peaking, and SDM are evaluated in Section 3.1 2.6 Additional Work Required to Change Control Element Assembly Group Definitions In order to implement the proposed change in CEA group definitions for CEAs 36 and 60, the following work items will be evaluated and performed in accordance with appropriate CEG procedures:

Update DCEDCS subcomponents (human machine interface, position display system, and motion logic controller) to reflect the reassignment of CEA groups.

Modify M-PGM configurations to swap the timing of the swapped CEAs and to categorize the swapped CEAs in the reassigned group.

Modify the plant process computer (PPC) configuration, including displays and reports, to reflect the reassignment of CEA groups.

Modify configuration files and inputs to the core monitoring system (POWERTRAX),

including the neutronics code (PRISM) and incore monitoring code (INPAX).

Operations training and procedure revisions will be completed in accordance with modification process requirements.

The modifications described for the DCEDCS, M-PGM, PPC, POWERTRAX, PRISM, and INPAX will not affect any other safety-related systems and will not affect the ability of the reactor protection system to safely shut down the reactor.

3.0 TECHNICAL EVALUATION

The Technical Evaluation examined the impacts to the Plant Safety Analysis for the proposed change to the assigned group for 2 CEAs during the current operating cycle, CC2C26, due to a degraded CEDM for CEA 36. The degraded CEDM does not impact the ability for CEA 36 to fully insert when tripped.

3.1 Safety Analysis As described in Section 2.5, the proposed change would swap the assigned group for CEA 36 and adjacent CEA 60 such that CEA 36 is part of regulating group 1 and CEA 60 is part of regulating group 5. This change would remain in place through the end of CC2C26 operation or until repairs of CEA 36 are completed, whichever occurs first. This change impacts the nuclear design and safety analysis characteristics for this reload core design. The reload safety

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 7 of 18 evaluation process, which is used for each new fuel cycle, has been re-performed as appropriate to determine the nuclear design parameter changes, impact to core and fuel performance, and impact to the accident analyses described in Updated Final Safety Analysis Report (UFSAR)

Chapter 14 for the proposed CEA group reassignments. The nuclear design parameter changes associated with core operation under the proposed CEA group assignments were evaluated against a set of bounding values contained in the pertinent accident and transient analyses for the plant. The results of those evaluations are discussed in this section.

NRC-approved reload safety analysis codes and methods were used to determine if the changes in nuclear design parameters remain bounded by the key safety parameters assumed in the UFSAR Chapter 14 safety analysis. Additionally, impacts on margins to fuel thermal and power peaking limits related to departure from nucleate boiling (DNB) and centerline fuel melt (CFM) safety criteria due to the change in power distribution attributable to operation with the control rod insertion under these CEA group assignments were evaluated.

An evaluation of impacts to core and fuel performance, as well as the impact to the safety analyses described in UFSAR Chapter 14 and safety analysis parameters, is summarized in the cycle-specific reload safety evaluation documentation (Attachments 5 and 6) to confirm the acceptability of reactor operation with the new core configuration. There were no changes in analytical methods, computer codes, or safety analysis limits used to perform the core reload safety evaluation for CC2C26 with these new CEA group assignments. The CC2C26 core design, with updated CEA group assignments, was performed with full core models due to the asymmetrical impact the CEA group reassignment could impart. Results of the safety analysis impact evaluation are described in the following subsections.

The TS LCOs and associated SRs of CEAs are not impacted by the proposed change. As described in Section 2, all CEAs remain available to perform their safety related trip functions as described in TS.

3.1.1 Shutdown Margin The proposed change has minimal impacts to the available shutdown margin (SDM). TS LCO 3.1.1 states that the required SDM shall be above the COLR limit of 3,500 percent milli-k (pcm).

Maintaining the SDM above this limit ensures the safety analysis described in UFSAR Chapter 14 remains bounding. An evaluation of the SDM with the proposed CEA group reassignments determined the impact to be an increase of SDM by <40 pcm. Overall, the CC2C26 SDM with the proposed CEA group reassignments remains above the required SDM of 3,500 pcm as specified in the COLR.

3.1.2 Other impacted parameters A review of other major neutronic parameters such as Delayed Neutron Fraction, Boron Concentration, MTC, Doppler Temperature Coefficient (DTC), and maximum fuel assembly and fuel rod burnups occurred with the different CEA group assignments. All parameters changed by less than 1%, primarily attributed to code rounding and a more accurate modeling of the previous outage duration.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 8 of 18 3.1.3 UFSAR Chapter 14 Accident Analyses Impacts The proposed CEA group swap for the remainder of CC2C26 has an impact on several UFSAR Chapter 14 accident analysis parameters routinely evaluated as part of the reload design process. Cycle-specific evaluations (Attachments 5 and 6) were performed to determine if the change in core design adversely impacts bounding key safety parameters assumed in the UFSAR Chapter 14 safety analyses and assess impacts on DNB and fuel thermal limits due to the change in power distribution. The bounding key safety parameters are developed in UFSAR Chapter 14 accident analyses of record (AORs) to ensure expected reactivity parameters and peaking conditions for various accident conditions are bounded. Therefore, if the cycle-specific evaluation meets the bounding parameters, the AOR remains satisfied. Results of the cycle-specific evaluations confirm that the limits assumed in the safety analysis remain bounding with incorporation of the additional cycle-specific restrictions specified in Section 3.2. Therefore, the proposed CEA group swap for CC2C26 does not impact the results presented in the UFSAR Chapter 14 accident analyses. Results and discussion of the UFSAR Chapter 14 accident analyses for CC2C26 with the CEA group reassignments are provided below.

3.1.3.1 Uncontrolled Control Rod Assembly Withdrawal from a Subcritical or Low Power Startup Condition (UFSAR Section 14.2)

A CEA Withdrawal Accident at Low Power or While Subcritical is defined as an uncontrolled addition of reactivity to the reactor core caused by withdrawal of CEAs while in low power or subcritical conditions, resulting in a power excursion. The maximum reactivity insertion rate in the detailed plant analysis is calculated to compare to limits assumed in UFSAR Chapter 14 accident analyses. The proposed group reassignments of CEA 36 and CEA 60 will impact the order and combination of CEA withdrawal, which in turn will impact the localized reactor core power distribution for events where a power excursion occurs. The limiting transient power excursion for this event occurs at a power significantly less than 1% RTP. These new CEA group assignments challenged the cladding strain acceptance criteria and were unable to produce acceptable results at the most limiting conditions. Increasing the lower bound of allowed operation to greater than 1% RTP allowed the clad strain results to meet their acceptance criteria.

The minimum DNB Ratio (DNBR) performance and Fuel Centerline Melt performance for this event remains bounded by the Uncontrolled Control Rod Bank Withdrawal at Power event discussed in Section 3.1.3.2.

Due to the inability to gain successful clad strain results for the entirety of this event, operating restrictions must be established to prevent the Uncontrolled Control Rod Assembly Withdrawal from a Subcritical or Low Power Startup Condition from occurring during those non-passing conditions. Specifically, any operation at or below 1% RTP or entry into Modes 3, 4, or 5 requires a repair of CEA 36 and re-establishment of the original CEA group assignments. These restrictions are described in Section 3.2 and enforced via the proposed change described in Section 2.5.

3.1.3.2 Uncontrolled Control Rod Bank Withdrawal at Power (UFSAR Section 14.2)

A CEA Withdrawal Accident at Power is defined as an uncontrolled addition of reactivity to the reactor core caused by withdrawal of CEAs while at part power or full power conditions, resulting

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 9 of 18 in a power excursion. The existing licensing basis is based predominantly on limiting ranges of DTC, MTC, and reactivity insertion rates. For this proposed CEA group re-assignment, those ranges of DTC, MTC and reactivity insertion rates remain unchanged. Therefore, the transient response of the licensing basis remains bounding, and no re-analysis of this event is required.

The minimum DNBR and peak Linear Heat Generation Rate (LHGR) continue to meet their acceptance criteria.

3.1.3.3 Control Rod Misoperation (UFSAR Section 14.11)

A Control Rod Misoperation is defined as a failure in the control rod system which causes a CEA to drop into the core. The existing licensing basis is based predominantly on a limiting range of dropped CEA worth and the most negative MTC for the cycle. For this CEA group re-assignment, the limiting MTC and range of dropped CEA worth remain unchanged. Therefore, the transient response of the licensing basis remains bounding, and no re-analysis of this event is required. The minimum DNBR and peak LHGR continue to meet their acceptance criteria.

3.1.3.4 Spectrum of Control Rod Ejection Accidents (UFSAR Section 14.13)

A Control Rod Ejection Accident is defined as a postulated rupture of a control rod drive mechanism allowing for full system pressure to act on the drive shaft, which ejects its control rod from the core. The existing licensing basis is based predominantly on a maximum rod motion based reactivity insertion rate and limiting ranges of the DTC and MTC. For the proposed CEA group re-assignment, the limiting DTC, MTC, and ejected CEA worth remain unchanged.

Therefore, the transient response of the licensing basis remains bounding, and no re-analysis of this event is required. The minimum DNBR and peak LHGR continue to meet their acceptance criteria.

3.1.3.5 Remaining UFSAR Chapter 14 Accident Analyses A review of all other UFSAR Chapter 14 accident analyses, including the Loss of Coolant Accident, was performed. These events were determined to remain bounded or unaffected with the new CEA group reassignments.

3.1.3.6 UFSAR Chapter 14 Accident Analyses Evaluation Summary The impact of the CEA group reassignments in CC2C26 on the nuclear design and safety analysis, including the UFSAR Chapter 14 events accident analyses, has been evaluated using the NRC-approved methods described in TS 5.6.5. These NRC-approved reload safety evaluation methods were used to determine if the proposed change in core configuration adversely impacts the bounding key safety parameters assumed in the UFSAR Chapter 14 Safety Analysis and to assess impacts on DNB and CFM due to the change in power distribution. Cycle-specific parameter evaluations for UFSAR Chapter 14 Safety Analysis parameters confirm that the values assumed in the safety analysis remain bounding for all UFSAR Chapter 14 Safety Analysis accidents with the exception of the Uncontrolled Control Rod Assembly Withdrawal from a Subcritical or Low Power Startup Condition. However, after the incorporation of the operating restrictions specified in Section 3.2 and enforced via the proposed change described in Section 2.5, there is no change to the UFSAR Chapter 14 accident analyses. Therefore, the proposed CEA group reassignments for CC2C26 do not impact the results presented in UFSAR Chapter 14.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 10 of 18 3.1.4 Trip Setpoint Verification - LCO Monitoring The DNB specified acceptable fuel design limit (SAFDL) is protected by way of the DNB LCO (SR 3.2.5.1) against two categories of anticipated operational occurrences (AOOs): (1) those requiring initial steady-state margin to the SAFDL, and (2) those requiring a combination of initial steady-state margin to the SAFDL and a RPS function. The limits on LHR (SR 3.2.1.2) represent limits within which the LHR algorithms are valid. When using excore detectors for LHR monitoring, LHR LCO COLR Figure 3.2.1-2 applies. With the proposed CEA group reassignments, additional margin in the negative ASI range was needed in the LHR LCO COLR Figure. The following revised COLR Figure 3.2.1-2 was created to support the proposed CEA group reassignments.

With this revised figure, limiting LHR calculation results demonstrate that margin exists and the adequacy of the LHR LCO function is maintained. This revised COLR Figure will be implemented as part of the proposed change.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 11 of 18 3.2 Cycle-specific Restrictions To ensure safety analyses performed remain bounding, the following plant operating restrictions are required for CC2C26 if the proposed change is implemented:

1. Operation is limited to core thermal power > 1% RTP. If core thermal power drops to 1%

RTP or lower, Unit 2 must continue to MODE 3.

2. If Unit 2 enters MODE 3, 4, or 5, the original CEA group assignments must be restored prior to entering MODE 2.

These restrictions are imposed based on the results of Uncontrolled Control Rod Assembly Withdrawal from Subcritical or Lower Power Startup Condition event analyses as discussed in Section 3.1.3.1. If, following implementation of the proposed change, the CEA group assignments are restored during CC2C26, reassessment of the reload licensing basis will be performed based on the actual operating history of the plant using the same NRC-approved reload safety analysis codes and methods used for this proposed change.

Reactivity guidance for power maneuvers will continue to be provided to the operating crews in accordance with existing procedures with additional predicted power distribution information provided, as required, including Tq (Azimuthal Power Tilt) and FrT (Total Integrated Radial Peaking Factor).

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria The proposed change has been evaluated to determine whether applicable regulations and requirements continue to be met. CCNPP was not licensed to the General Design Criteria (GDCs) listed in 10 CFR Part 50, Appendix A, but was licensed based on the Atomic Energy Commission (AEC) proposed Principal Design Criteria (PDCs) published on July 10, 1967. The relevant principal design criteria for CCNPP are described in Appendix 1C of the CCNPP UFSAR. CEG has determined that the proposed change does not require any exemptions or relief from the following current applicable regulations and regulatory requirements, which were reviewed in making this determination:

10 CFR 50.36, Technical Specifications 10 CFR 50.36(c) provides that TS will include Limiting Conditions for Operation (LCOs) which are "the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met." In addition, 10 CFR 50.36 requires that a licensee's TS be derived from the analyses and evaluation included in the safety analysis report.

The proposed change does not involve any modifications to TS, including LCOs, Surveillance Requirements, required remedial actions, or shutdown requirements.

The proposed change does not affect CCNPP's compliance with the intent of 10 CFR 50.36.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 12 of 18 10 CFR 50.62, Requirements for reduction of risk from anticipated transients without scram (ATWS) events for light-water-cooled nuclear power plants 10 CFR 50.62(c)(2) requires that each pressurized water reactor manufactured by Combustion Engineering or by Babcock and Wilcox must have a diverse scram system from the sensor output to interruption of power to the control rods. This scram system must be designed to perform its function in a reliable manner and be independent from the existing reactor trip system (from sensor output to interruption of power to the control rods).

The proposed change does not impact CCNPPs scram system function or reliability.

The degraded CEDM for CEA 36 does not impact the ability for CEA 36 to fully insert when tripped.

The proposed change does not affect CCNPP's compliance with the intent of 10 CFR 50.62.

UFSAR Appendix 1C Criterion 6, Reactor Core Design (Similar to GDC 10, Reactor Design)

UFSAR Appendix 1C Criterion 6 requires that the reactor core be designed to function throughout its design lifetime, without exceeding acceptable fuel damage limits which have been stipulated and justified. The core design, together with reliable process and decay heat removal systems, shall provide for this capability under all expected conditions of normal operation with appropriate margins for uncertainties and for transient situations which can be anticipated, including the effects of the loss of power to recirculation pumps, tripping out of a turbine generator set, isolation of the reactor from its primary heat sink, and loss of all off-site power.

Analyses documented in Attachments 5 and 6 and summarized in Section 3 demonstrate that the proposed change maintains appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including uncertainties and for transient situations which can be anticipated.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criterion 6.

UFSAR Appendix 1C Criterion 7, Suppression of Power Oscillations (Similar to GDC 12, Suppression of Reactor Power Oscillations)

UFSAR Appendix 1C Criterion 7 requires that the core design, together with reliable controls, ensures that power oscillations which could cause damage in excess of acceptable fuel damage limits are not possible or can be readily suppressed.

The proposed change does not significantly impact the control rod worth of the CEAs.

Therefore, the ability of the CEAs to readily suppress power oscillations is not impacted by the proposed change.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criterion 7.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 13 of 18 UFSAR Appendix 1C Criterion 8, Overall Power Coefficient (Similar to GDC 11, Reactor Inherent Protection)

UFSAR Appendix 1C Criterion 8 requires that the reactor be designed so that the overall power coefficient in the power operating range shall not be positive.

Analyses documented in Attachments 5 and 6 and summarized in Section 3 demonstrate that the proposed change impacts reactivity feedback coefficients by less than 1% and that reactivity feedback coefficients are not positive in the power operating range.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criterion 8.

UFSAR Appendix 1C Criterion 14, Core Protection Systems, and Criterion 15, Engineered Safety Features Protection Systems (Similar to GDC 20, Protection system functions)

UFSAR Appendix 1C Criterion 14 requires that core protection systems together with associated equipment be designed to act automatically to prevent or to suppress conditions that could result in exceeding acceptable fuel damage limits.

UFSAR Appendix 1C Criterion 15 requires that protection systems be provided for sensing accident situations and initiating the operation of necessary engineered safety features.

The proposed change does not impact core protection systems, engineered safety features protection systems, or their ability to sense accident situations and act automatically to prevent or to suppress conditions that could result in exceeding acceptable fuel damage limits and operate engineered safety features.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criteria 14 and 15.

UFSAR Appendix 1C Criterion 19, Protection System Reliability, and Criterion 20, Protection Systems Redundancy and Independence (Similar to GDC 21, Protection system reliability and testability)

UFSAR Appendix 1C Criterion 19 requires that protection systems be designed for high functional reliability and in-service testability commensurate with the safety functions to be performed.

UFSAR Appendix 1C Criterion 20 requires that redundancy and independence designed into protection systems be sufficient to assure that no single failure or removal from service of any component or channel of a system will result in loss of the protection function. The redundancy provided shall include, as a minimum, two channels of protection for each protection function to be served. Different principles shall be used where necessary to achieve true independence of redundant instrumentation components.

The proposed change is necessary due to a degraded CEDM UGC that is inhibiting operator demanded motion for CEA 36. The degraded CEDM does not impact the ability

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 14 of 18 for CEA 36 to fully insert when tripped. The proposed change does not impact the reliability, redundancy, or independence of protection systems.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criteria 19 and 20.

UFSAR Appendix 1C Criterion 27, Redundancy of Reactivity Control, Criterion 28, Reactivity Hot Shutdown Capability, Criterion 29, Reactivity Shutdown Capability, and Criterion 30, Reactivity Holddown Capability (Similar to GDC 26, Reactivity control system redundancy and capability, and GDC 27, Combined reactivity control systems capability)

UFSAR Appendix 1C Criterion 27 requires that at least two independent reactivity control systems, preferably of different principles, be provided.

UFSAR Appendix 1C Criterion 28 requires that at least two of the reactivity control systems provided shall independently be capable of making and holding the core subcritical from any hot standby or hot operating condition, including those resulting from power changes, sufficiently fast to prevent exceeding acceptable fuel damage limits.

UFSAR Appendix 1C Criterion 29 requires that at least one of the reactivity control systems provided be capable of making the core subcritical under any condition (including anticipated operational transients) sufficiently fast to prevent exceeding acceptable fuel damage limits. Shutdown margins greater than the maximum worth of the most effective control rod when fully withdrawn shall be provided.

UFSAR Appendix 1C Criterion 30 requires that at least one of the reactivity control systems provided be capable of making and holding the core subcritical under any conditions with appropriate margins for contingencies.

The proposed change maintains two independent reactivity control systems of different principles (i.e., CEAs and boration). Both reactivity control systems will continue to independently be capable of making and holding the core subcritical from any hot standby or hot operating condition, including those resulting from power changes, sufficiently fast to prevent exceeding acceptable fuel damage limits.

Analyses documented in Attachments 5 and 6 and summarized in Section 3 demonstrate that, after the incorporation of the operating restrictions specified in Section 3.2 and enforced via the proposed changes described in Section 2.5, with the proposed CEA group reassignments for CC2C26:

the reactivity control systems are capable of making the core subcritical under any condition (including anticipated operational transients) sufficiently fast to prevent exceeding acceptable fuel damage limits, shutdown margin remains greater than the maximum worth of the most effective control rod when fully withdrawn, and the reactivity control systems are capable of making and holding the core subcritical under any conditions with appropriate margins for contingencies.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 15 of 18 The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criteria 27, 28, 29, and 30.

UFSAR Appendix 1C Criterion 31, Reactivity Control Systems Malfunction (Similar to GDC 25, Protection system requirements for reactivity control malfunctions)

UFSAR Appendix 1C Criterion 31 requires that the reactivity control systems be capable of sustaining any single malfunction, such as unplanned continuous withdrawal (not ejection) of a control rod, without causing a reactivity transient which could result in exceeding acceptable fuel damage limits.

Analyses documented in Attachments 5 and 6 and summarized in Section 3 demonstrate that, after the incorporation of the operating restrictions specified in Section 3.2 and enforced via the proposed changes described in Section 2.5, there is no change to the UFSAR Chapter 14 accident analyses and the reactivity control systems remain capable of sustaining any single malfunction. The proposed CEA group reassignments for CC2C26 do not impact the results presented in UFSAR Chapter 14.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criterion 31.

UFSAR Appendix 1C Criterion 32, Maximum Reactivity Worth of Control Rods (Similar to GDC 28, Reactivity limits)

UFSAR Appendix 1C requires that limits, which include considerable margin, shall be placed on the maximum reactivity worth of control rods or elements and on rates at which reactivity can be increased to ensure that the potential effects of a sudden or large change of reactivity cannot (a) rupture the reactor coolant pressure boundary or (b) disrupt the core, its support structures or other vessel internals sufficiently to impair the effectiveness of emergency core cooling.

Analyses documented in Attachments 5 and 6 and summarized in Section 3 demonstrate that, after the incorporation of the operating restrictions specified in Section 3.2 and enforced via the proposed changes described in Section 2.5, there is no change to the UFSAR Chapter 14 accident analyses, including those evaluating control rod withdrawal, misoperation, and ejection.

The proposed change does not affect CCNPP's compliance with the intent of UFSAR Appendix 1C Criterion 32.

4.2 Precedent The following precedents are applicable to this submittal. In precedent 4.2.1, the U.S. NRC granted Callaway Plant Unit 1 an amendment allowing operation for one cycle with no control rod assembly installed in one core location. The Callaway change and its impacts are similar to the proposed change for CC2C26, and a similar evaluation of safety analyses and other impacts was required. In precedent 4.2.2, the U.S. NRC granted Calvert Cliffs Unit 1 an amendment allowing operation with the center CEA excluded from TS requirements for operability and alignment for one cycle. The previous Calvert Cliffs change is similar to the proposed change for CC2C26 since both address a CEA unable to be moved by operator demand.

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 16 of 18

1. Letter from Mahesh L. Chawla (U.S. NRC) to Fadi Diya (Ameren Missouri), Callaway Plant, Unit No. 1 - Issuance of Amendment No. 239 RE: Revision to Technical Specifications to Allow Control Rod to be Removed for Cycle 28 (EPID L-2025-LLA-0016), dated April 10, 2025 (ADAMS Accession No. ML25084A354)
2. Letter from Daniel G. McDonald (U.S. NRC) to Mr. G. C. Creel (Baltimore Gas and Electric Company), Issuance of Amendment for Calvert Cliffs Nuclear Power Plant Unit 1 (TAC No. 79709), dated February 20, 1991 (ADAMS Accession No. ML010470133) 4.3 No Significant Hazards Consideration Constellation Energy Generation, LLC (CEG), proposes a swap of the assigned group for 2 Control Element Assemblies (CEAs) during the current operating cycle, Calvert Cliffs Unit 2 Cycle 26 (CC2C26). This amendment is necessary due to a degraded Control Element Drive Mechanism (CEDM) upper gripper coil (UGC) that is inhibiting operator demanded motion for CEA 36. The degraded CEDM does not impact the ability for CEA 36 to fully insert when tripped.

Constellation Energy Generation, LLC (CEG) has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, Issuance of amendment, as discussed below:

1.

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

Response: No.

The Control Element Assemblies (CEAs) and the analyses associated with them are not accident initiators. An evaluation of shutdown margin (SDM) with the proposed change remains above the required SDM. The response of the CEAs to an accident and their impact on the core is analyzed using conservative techniques and NRC-approved reload safety analysis codes and methods. Analysis results were compared to approved acceptance criteria. These evaluation results show that the response to an accident, after implementation of the proposed change, is within approved acceptance criteria.

The proposed change will not alter or prevent the ability of the CEAs from performing their intended function to mitigate the consequences of an initiating event within the assumed acceptance limits. Therefore, the proposed change does not affect accident or transient initiation or consequences.

Therefore, the proposed change does 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 change does not adversely affect any fission product barrier, nor does it alter the safety function of safety systems, structures, or components, or their roles in

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 17 of 18 accident prevention or mitigation. The proposed change involves no physical changes beyond those required to ensure the affected CEAs move with their reassigned groups, their movement is correctly displayed to operators, and analyses performed by the core monitoring system reflect the reassigned groups. The proposed change was determined to have no impact on previously evaluated accident analyses. The proposed change results in operation within fuel design limits.

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

3.

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

Response: No.

The proposed change does not adversely affect any fission product barrier, nor does it alter the safety function of safety systems, structures, or components, or their roles in accident prevention or mitigation. The proposed change has an impact on several accident analysis parameters routinely evaluated as part of the reload design process.

Cycle-specific evaluations were performed to determine if the change in core design adversely impacts bounding key safety parameters assumed in the safety analyses and assess impacts on DNB and fuel thermal limits due to the change in power distribution.

The proposed change, including operational restrictions for restoring the original CEA group assignments, was determined to have no impact on previously evaluated accident analyses. The proposed change does not result in exceeding design basis limits. All licensed safety margins are maintained.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, CEG concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.4 Conclusions 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 Commissions 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

CEG has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, "Standards for Protection Against Radiation." However, 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

Emergency License Amendment Request One-Time Change to Calvert Cliffs Unit 2 Control Element Assembly Group Definitions Page 18 of 18 proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22, "Criterion for categorical exclusion; identification of licensing and regulatory actions eligible for categorical exclusion or otherwise not requiring environmental review," paragraph (c)(9). Therefore, pursuant to 10 CFR 51.22, paragraph (b), no environmental impact statement or environmental assessment needs to be prepared in connection with the proposed amendment.

6.0 REFERENCES

6.1 Letter from Douglas V. Pickett (U.S. NRC) to Mr. George H. Gellrich (Calvert Cliffs Nuclear Power Plant, LLC), Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 -

Amendment RE: Transition from Westinghouse Nuclear Fuel to Areva Nuclear Fuel (TAC Nos. ME2831 and ME2832), dated February 18, 2011 (ADAMS Accession No. ML110390224).

6.2 Letter from Christopher J. Smith (Constellation) to U.S. Nuclear Regulatory Commission, Core Operating Limits Report for Unit 2, Cycle 26, Revision 0, dated March 11, 2025 (ADAMS Accession No. ML25072A033 and ML25072A034).

ATTACHMENT 2 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 Proposed Facility Operating License, Appendix C, Additional Conditions Page (Markup) 11

11 Appendix C (Contd)

Additional Conditions Facility Operating License No. DPR-69 Amendment No. 323317 Amendment No.

Additional Condition Implementation Date 317 Up to two Framatome PROtect' Lead Test Assemblies utilizing Chromium-coated M5 cladding and chromia doped pellets may be placed in limiting regions of the core for up to 3 cycles commencing with the implementation of Amendment 317.

With implementation of this Amendment 317 The safety limits specified in TS 2.1.1.2 regarding fuel centerline melt temperature for Framatome fuel, < 5081°F, decreasing by 58°F per 10,000 MWD/MTU and adjusted for burnable poison per XN-NF-79-56(P)(A),

Revision 1, Supplement 1 is not applicable for the Framatome PROtect' Lead Test Assemblies utilizing Chromium-coated M5 cladding and chromia doped pellets for up to 3 cycles commencing with the implementation of Amendment 317.

With implementation of this Amendment 317 The requirement that the RODEX2 predicted rod internal pressure shall remain below the steady state system pressure is not applicable for the Framatome PROtect' Lead Test Assemblies utilizing Chromium coated M5 cladding and chromia doped pellets for up to 3 cycles commencing with the implementation of Amendment 317.

With implementation of this Amendment Insert:

For Unit 2 Cycle 26 only:

CEA 36 (core location L-19) and CEA 60 (core location J-20) group assignments may be swapped such that CEA 36 is part of regulating group 1 and CEA 60 is part of regulating group 5. If CEA 36 and CEA 60 group assignments are swapped and core thermal power is lowered to less than or equal to 1% of rated thermal power, Unit 2 shall continue to MODE 3. If CEA 36 and CEA 60 group assignments are swapped and Unit 2 enters MODE 3, 4, or 5, the original CEA group assignments shall be restored prior to entering MODE 2. NRC prior review and approval is not required to restore the original CEA group assignments.

Insert:

This amendment is effective immediately and shall be implemented within 14 days of issuance.

ATTACHMENT 3 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 Proposed Facility Operating License, Appendix C, Additional Conditions Page (Clean) 11

11 Appendix C (Contd)

Additional Conditions Facility Operating License No. DPR-69 Amendment No. 330317 Amendment No.

Additional Condition Implementation Date 317 With implementation of this Amendment 317 With implementation of this Amendment 317 With implementation of this Amendment This amendment is effective immediately and shall be implemented within 14 days of issuance.

Up to two Framatome PROtect' Lead Test Assemblies utilizing Chromium-coated M5 cladding and chromia doped pellets may be placed in limiting regions of the core for up to 3 cycles commencing with the implementation of Amendment 317.

The safety limits specified in TS 2.1.1.2 regarding fuel centerline melt temperature for Framatome fuel, < 5081°F, decreasing by 58°F per 10,000 MWD/MTU and adjusted for burnable poison per XN-NF-79-56(P)(A),

Revision 1, Supplement 1 is not applicable for the Framatome PROtect' Lead Test Assemblies utilizing Chromium-coated M5 cladding and chromia doped pellets for up to 3 cycles commencing with the implementation of Amendment 317.

The requirement that the RODEX2 predicted rod internal pressure shall remain below the steady state system pressure is not applicable for the Framatome PROtect' Lead Test Assemblies utilizing Chromium coated M5 cladding and chromia doped pellets for up to 3 cycles commencing with the implementation of Amendment 317.

For Unit 2 Cycle 26 only:

CEA 36 (core location L-19) and CEA 60 (core location J-20) group assignments may be swapped such that CEA 36 is part of regulating group 1 and CEA 60 is part of regulating group

5. If CEA 36 and CEA 60 group assignments are swapped and core thermal power is lowered to less than or equal to 1% of rated thermal power, Unit 2 shall continue to MODE 3. If CEA 36 and CEA 60 group assignments are swapped and Unit 2 enters MODE 3, 4, or 5, the original CEA group assignments shall be restored prior to entering MODE 2. NRC prior review and approval is not required to restore the original CEA group assignments.

330

ATTACHMENT 4 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 Affidavit from Framatome Supporting the Withholding of Information in Attachment 6 from Public Disclosure

A F F I D A V I T 1.

My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.

2.

I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.

3.

I am familiar with the Framatome information contained in Framatome Document No. ANP-4173P Revision 0, Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report. Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.

4.

This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.

6.

The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:

(a)

The information reveals details of Framatomes research and development plans and programs or their results.

For Information Only

(b)

Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.

(c)

The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.

(d)

The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.

(e)

The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.

The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(b), 6(c), 6(d), and 6(e) above.

7.

In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8.

Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9.

The foregoing statements are true and correct to the best of my knowledge, information, and belief.

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

Executed on October 15, 2025.

Philip A. Opsal Manager, Product Licensing Framatome Inc.

Philip A. Opsal For Information Only

ATTACHMENT 5 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 Framatome Report ANP-4173NP Rev. 0, Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report (Non-Proprietary)

Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report ANP-4173NP Revision 0 October 2025 Proprietary (c) 2025 Framatome Inc.

For Information Only

ANP-4173NP Revision 0 Copyright © 2025 Framatome Inc.

All Rights Reserved FRAMATOME TRADEMARKS FUELGUARD, HMP, HTP, M5, M5Framatome, and MONOBLOC are trademarks or registered trademarks of Framatome or its affiliates, in the USA or other countries.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page i Nature of Changes Rev Section(s) or Page(s)

Description and Justification 000 All Initial Release For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page ii Contents Page

1.0 INTRODUCTION

............................................................................................... 1-1 2.0

SUMMARY

........................................................................................................ 2-1 3.0 DESIGN DESCRIPTION................................................................................... 3-1 3.1 General Core Description....................................................................... 3-1 3.2 Mechanical Design................................................................................. 3-1 3.3 Nuclear Design...................................................................................... 3-1 3.4 Thermal-Hydraulic Design...................................................................... 3-2 4.0 PLANT OPERATING CONDITIONS................................................................. 4-1 4.1 Plant Characteristics and Initial Conditions............................................. 4-1 4.2 Effects of Fuel Rod Bowing..................................................................... 4-1 4.3 Radiological Analysis.............................................................................. 4-1 4.4 Plant Operating Restrictions for Unit 2 Cycle 26 with CEA Swap....................................................................................................... 4-1 5.0 EVENT REVIEW AND ANALYSIS.................................................................... 5-1 5.1 Summary of Plant Changes.................................................................... 5-1 5.1.1 Plant-Related Changes................................................................ 5-1 5.1.1.1 Plant Configuration Changes....................................... 5-1 5.1.1.2 Modes of Operation...................................................... 5-4 5.1.1.3 Operating States.......................................................... 5-4 5.1.1.4 Operating Conditions................................................... 5-4 5.1.1.5 Probable Event Initiators.............................................. 5-4 5.1.1.6 RPS and ESF System Functions................................. 5-4 5.1.1.7 Technical Specifications Changes (Customer Initiated)....................................................................... 5-4 5.1.2 Fuel Design Characteristics......................................................... 5-4 5.1.3 Core Composition........................................................................ 5-4 5.1.4 Neutronics Characteristics........................................................... 5-4 5.1.5 Analytical Methodologies............................................................. 5-5 5.1.6 Limiting Assumptions................................................................... 5-7 5.1.7 Additional Customer-Requested Changes................................... 5-7 5.1.8 Inlet Temperature Coastdown...................................................... 5-7 5.2 Chapter 14 Event Review....................................................................... 5-7 5.2.1 Increase in Heat Removal by the Secondary System (SRP 15.1)................................................................................... 5-9 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page iii 5.2.1.1 Decrease in Feedwater Temperature (SRP 15.1.1, UFSAR 14.7)................................................................ 5-9 5.2.1.1.1 Event Description......................................... 5-9 5.2.1.1.2 Event Disposition and Justification............... 5-9 5.2.1.2 Increase in Feedwater Flow (SRP 15.1.2, UFSAR 14.7, 14.12)................................................................ 5-10 5.2.1.2.1 Event Description....................................... 5-10 5.2.1.2.2 Event Disposition and Justification............. 5-10 5.2.1.3 Increase in Steam Flow (SRP 15.1.3, UFSAR 14.4)........................................................................... 5-10 5.2.1.3.1 Event Description....................................... 5-10 5.2.1.3.2 Event Disposition and Justification............. 5-11 5.2.1.4 Inadvertent Opening of a Steam Generator Relief or Safety Valve (SRP 15.1.4, UFSAR 14.12)............ 5-12 5.2.1.4.1 Event Description....................................... 5-12 5.2.1.4.2 Event Disposition and Justification............. 5-12 5.2.1.5 Steam System Piping Failures Inside and Outside of Containment (SRP 15.1.5, UFSAR 14.14)............. 5-13 5.2.1.5.1 Event Description....................................... 5-13 5.2.1.5.2 Event Disposition and Justification............. 5-13 5.2.2 Decrease in Heat Removal by the Secondary System (SRP 15.2)................................................................................. 5-16 5.2.2.1 Loss of External Load (SRP 15.2.1, UFSAR 14.5)..... 5-16 5.2.2.1.1 Event Description....................................... 5-16 5.2.2.1.2 Event Disposition and Justification............. 5-16 5.2.2.2 Turbine Trip (SRP 15.2.2, UFSAR 14.5).................... 5-16 5.2.2.2.1 Event Description....................................... 5-16 5.2.2.2.2 Event Disposition and Justification............. 5-16 5.2.2.3 Loss of Condenser Vacuum (SRP 15.2.3)................. 5-17 5.2.2.4 Closure of Main Steam Isolation Valves (SRP 15.2.4)........................................................................ 5-17 5.2.2.4.1 Event Description....................................... 5-17 5.2.2.4.2 Dual MSIV Closure (UFSAR 14.5)............. 5-17 5.2.2.4.3 Single MSIV Closure (UFSAR 14.12)........ 5-17 5.2.2.5 Steam Pressure Regulator Failure (SRP 15.2.5)....... 5-19 5.2.2.6 Loss of Non-Emergency AC Power (SRP 15.2.6, UFSAR 14.10)............................................................ 5-19 5.2.2.7 Loss of Normal Feedwater Flow (SRP 15.2.7, UFSAR 14.6).............................................................. 5-19 5.2.2.7.1 Event Description....................................... 5-19 5.2.2.7.2 Event Disposition and Justification............. 5-20 5.2.2.8 Feedwater System Pipe Breaks Inside and Outside Containment (SRP 15.2.8, UFSAR 14.26)... 5-20 5.2.2.8.1 Event Description....................................... 5-20 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page iv 5.2.2.8.2 Event Disposition and Justification............. 5-21 5.2.3 Decrease in Reactor Coolant System Flow (SRP 15.3)................................................................................. 5-22 5.2.3.1 Loss of Forced Reactor Coolant Flow (SRP 15.3.1, UFSAR 14.9)........................................ 5-22 5.2.3.1.1 Event Description....................................... 5-22 5.2.3.1.2 Event Disposition and Justification............. 5-22 5.2.3.2 Flow Controller Malfunction (SRP 15.3.2).................. 5-23 5.2.3.3 Reactor Coolant Pump Rotor Seizure (SRP 15.3.3, UFSAR 14.16)...................................... 5-23 5.2.3.3.1 Event Description....................................... 5-23 5.2.3.3.2 Event Disposition and Justification............. 5-24 5.2.3.4 Reactor Coolant Pump Shaft Break (SRP 15.3.4)..... 5-25 5.2.4 Reactivity and Power Distribution Anomalies (SRP 15.4)................................................................................. 5-26 5.2.4.1 Uncontrolled Control Rod Assembly Withdrawal from a Subcritical or Low Power Startup Condition (SRP 15.4.1, UFSAR 14.2)........................................ 5-26 5.2.4.1.1 Event Description....................................... 5-26 5.2.4.1.2 Event Disposition and Justification............. 5-27 5.2.4.2 Uncontrolled Control Rod Bank Withdrawal at Power (SRP 15.4.2, UFSAR 14.2)............................. 5-28 5.2.4.2.1 Event Description....................................... 5-28 5.2.4.2.2 Event Disposition and Justification............. 5-29 5.2.4.3 Control Rod Misoperation (SRP 15.4.3, UFSAR 14.11)......................................................................... 5-30 5.2.4.3.1 Event Description....................................... 5-30 5.2.4.3.2 Event Disposition and Justification............. 5-30 5.2.4.4 Startup of an Inactive Loop (SRP 15.4.4)................... 5-31 5.2.4.4.1 Event Description....................................... 5-31 5.2.4.4.2 Event Disposition and Justification............. 5-32 5.2.4.5 Flow Controller Malfunction (SRP 15.4.5).................. 5-32 5.2.4.6 CVCS Malfunction That Results in a Decrease in the Boron Concentration in the Reactor Coolant (SRP 15.4.6).............................................................. 5-32 5.2.4.6.1 Event Description....................................... 5-32 5.2.4.6.2 Event Disposition and Justification............. 5-32 5.2.4.7 Inadvertent Loading and Operation of a Fuel Assembly in an Improper Position - Misload (SRP 15.4.7).............................................................. 5-33 5.2.4.7.1 Event Description....................................... 5-33 5.2.4.7.2 Event Disposition and Justification............. 5-34 5.2.4.8 Spectrum of Control Rod Ejection Accidents (SRP 15.4.8, UFSAR 14.13)...................................... 5-35 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page v 5.2.4.8.1 Event Description....................................... 5-35 5.2.4.8.2 Event Disposition and Justification............. 5-35 5.2.4.9 Spectrum of Rod Drop Accidents (BWR)

(SRP 15.4.9).............................................................. 5-36 5.2.5 Increases in Reactor Coolant System Inventory (SRP 15.5)................................................................................. 5-36 5.2.5.1 Inadvertent Operation of the ECCS That Increases Reactor Coolant Inventory (SRP 15.5.1).................... 5-36 5.2.5.2 CVCS Malfunction That Increases Reactor Coolant Inventory (SRP 15.5.2, UFSAR 14.25)........ 5-37 5.2.5.2.1 Event Description....................................... 5-37 5.2.5.2.2 Event Disposition and Justification............. 5-37 5.2.6 Decrease in Reactor Coolant Inventory (SRP 15.6)................... 5-37 5.2.6.1 Inadvertent Opening of a PWR Pressurizer Pressure Relief Valve (SRP 15.6.1, UFSAR 14.8).... 5-37 5.2.6.1.1 Event Description....................................... 5-37 5.2.6.1.2 Event Disposition and Justification............. 5-37 5.2.6.2 Radiological Consequences of the Failure of Small Lines Carrying Primary Coolant Outside of Containment (SRP 15.6.2)......................................... 5-38 5.2.6.3 Radiological Consequences of Steam Generator Tube Failure (SRP 15.6.3, UFSAR 14.15)................ 5-39 5.2.6.3.1 Event Description....................................... 5-39 5.2.6.3.2 Event Disposition and Justification............. 5-40 5.2.6.4 Radiological Consequences of a Main Steam Line Failure Outside Containment (BWR) (SRP 15.6.4).... 5-41 5.2.6.5 Loss of Coolant Accidents Resulting from a Spectrum of Postulated Piping Breaks within the Reactor Coolant Pressure Boundary (SRP 15.6.5)... 5-41 5.2.6.5.1 Event Description....................................... 5-41 5.2.6.5.2 Large Break LOCA..................................... 5-41 5.2.6.5.3 Small Break LOCA..................................... 5-41 5.2.6.5.4 Condition Reports...................................... 5-42 5.2.6.5.5 Post-LOCA Shutdown Condition................ 5-43 5.2.7 Radioactive Releases from a Subsystem or Component (SRP 15.7).............................................................. 5-43 5.2.7.1 Waste Gas System Failure (SRP 15.7.1, UFSAR 14.22)......................................................................... 5-43 5.2.7.2 Radioactive Liquid Waste System Leak or Failure (Release to Atmosphere) (SRP 15.7.2, UFSAR 14.23)......................................................................... 5-43 5.2.7.3 Postulated Radioactive Releases due to Liquid-Containing Tank Failures (SRP 15.7.3)...................... 5-43 5.2.7.4 Radiological Consequences of Fuel Handling Accident (SRP 15.7.4, UFSAR 14.18)........................ 5-43 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page vi 5.2.7.4.1 Event Description....................................... 5-43 5.2.7.4.2 Event Disposition and Justification............. 5-43 5.2.7.5 Spent Fuel Cask Drop Accidents (SRP 15.7.5, UFSAR 5.6.1.5).......................................................... 5-44 5.2.7.6 Spent Fuel Pit Water Loss (SRP 15.7.6).................... 5-44 5.2.8 Anticipated Transients Without Scram (SRP 15.8, UFSAR 7.11).............................................................................. 5-44 5.3 Other Analyses..................................................................................... 5-44 5.3.1 Control Room Habitability.......................................................... 5-44 5.3.2 Equipment Qualification Source Terms...................................... 5-44 5.3.3 Low Temperature Overpressurization Protection System....................................................................................... 5-44 5.3.4 Pressure Isolation Valve Testing................................................ 5-44 5.3.5 Alternate Source Term............................................................... 5-44 5.3.6 Turbine Generator Overspeed Incident (UFSAR 14.19)......................................................................................... 5-45 5.3.6.1 Event Description....................................................... 5-45 5.3.6.2 Event Disposition and Justification............................. 5-45 5.3.7 Containment Response (UFSAR 14.20).................................... 5-46 5.3.7.1 Event Description....................................................... 5-46 5.3.7.2 Event Disposition and Justification............................. 5-46 5.3.8 Maximum Hypothetical Accident (UFSAR 14.24)....................... 5-47 5.3.9 Incore Instrument Melt............................................................... 5-47 5.3.10 Station Blackout......................................................................... 5-47 5.3.11 Fuel Storage Rack Criticality...................................................... 5-47 6.0 TRIP SETPOINT VERIFICATION..................................................................... 6-1 6.1 Reactor Protection System..................................................................... 6-1 6.2 Specified Acceptable Fuel Design Limits................................................ 6-1 6.3 Limiting Safety System Settings............................................................. 6-2 6.3.1 Local Power Density.................................................................... 6-2 6.3.2 Thermal Margin/Low Pressure..................................................... 6-2 6.3.3 Additional Trip Functions.............................................................. 6-3 6.4 Limiting Conditions for Operation............................................................ 6-4 6.4.1 DNB Monitoring............................................................................ 6-4 6.4.2 Linear Heat Rate Monitoring........................................................ 6-5 7.0

SUMMARY

OF ANALYSES PERFORMED...................................................... 7-1 8.0 CODES.............................................................................................................. 8-1

9.0 REFERENCES

................................................................................................. 9-1 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page vii List of Tables Table 3-1 Fuel Inventory Characteristics..................................................................... 3-3 Table 3-2 Neutronics Characteristics......................................................................... 3-4 Table 3-3 Shutdown Margin........................................................................................ 3-5 Table 3-4 Thermal-Hydraulic Limits............................................................................. 3-6 Table 4-1 General Core Parameters and Plant Operating Conditions........................ 4-3 Table 5-1 Summary of Plant Configuration Changes.................................................. 5-3 Table 5-2 RLBLOCA AOR Limiting Results.............................................................. 5-41 Table 5-3 SBLOCA AOR Limiting Results................................................................. 5-42 Table 5-4 Summary of LOCA PCT Penalties............................................................ 5-42 Table 5-5 Disposition of Events Summary................................................................ 5-48 Table 6-1 Uncertainties Applied in LPD LSSS Verifications........................................ 6-7 Table 6-2 Uncertainties Applied in the TM/LP Verification.......................................... 6-8 Table 6-3 Transient Biases Applied in the TM/LP LSSS Verifications......................... 6-9 Table 6-4 Transient Biases Applied in the TM/LP and LPD LSSS Verifications........ 6-10 Table 6-5 Additional Trip Setpoints........................................................................... 6-11 Table 6-6 General Uncertainties Applied in the LCO Calculations............................ 6-12 Table 6-7 Uncertainties Applied in DNB LCO LOCF Calculations............................. 6-13 Table 6-8 Power Measurement Uncertainty............................................................. 6-14 Table 7-1 Determination of Thermal-Hydraulic Analyses-of-Record........................... 7-2 Table 8-1 Codes used to support the Safety Analysis Report..................................... 8-1 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page viii List of Figures Figure 3-1 Full Core Loading Pattern.......................................................................... 3-7 Figure 3-2 Fuel Rod Assembly Lattices....................................................................... 3-8 Figure 3-3 Allowable time to Realign CEA Versus Initial Total Radial Peaking Factor (FrT).............................................................................................. 3-11 Figure 3-4 Quarter-Core Assembly Map................................................................... 3-12 Figure 3-5 Assembly Relative Power Density at BOC (100 MWd/MTU), HFP, ARO, Equilibrium Xenon.......................................................................... 3-13 Figure 3-6 Assembly Relative Power Density at HFP, ARO, Equilibrium Xenon (10,000 MWd/MTU)................................................................................. 3-14 Figure 3-7 Assembly Relative Power Density at EOC, HFP, ARO, Equilibrium Xenon...................................................................................................... 3-15 Figure 3-8 Assembly Relative Power Density with Bank 5 Inserted to PDIL at BOC (100 MWd/MTU) HFP, Equilibrium Xenon...................................... 3-16 Figure 3-9 Assembly Relative Power Density with Bank 5 Inserted to PDIL at EOC, HFP, Equilibrium Xenon................................................................ 3-17 Figure 3-10 Assembly Average Burnup at BOC........................................................ 3-18 Figure 3-11 Assembly Average Burnup at EOC........................................................ 3-19 Figure 5-1 CEA Bank Assignment Swap..................................................................... 5-3 Figure 6-1 LPD LSSS COLR Barn............................................................................ 6-15 Figure 6-2 Verification of LPD LSSS......................................................................... 6-16 Figure 6-3 TM/LP Trip Function A1: a) COLR, b) analysis........................................ 6-17 Figure 6-4 TM/LP Trip Function QR1........................................................................ 6-18 Figure 6-5 DNB LCO COLR Barn............................................................................. 6-19 Figure 6-6 Verification of DNB LCO for the Loss of Forced Reactor Coolant Flow Transient................................................................................................. 6-20 Figure 6-7 LPD LCO COLR Barn (updated for CEA swapped condition).................. 6-21 Figure 6-8 Verification of LPD LCO........................................................................... 6-22 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page ix Nomenclature Acronym Definition ADV Atmospheric Dump Valve AFAS Auxiliary Feedwater Actuation System AFW Auxiliary Feedwater AOO Anticipated Operational Occurrence AOR Analysis of Record APD Axial Power Distribution ARI All Rods In ARO All Rods Out ASGPT Asymmetric Steam Generator Pressure Trip ASI Axial Shape Index AST Alternate Source Term BOC Beginning of Cycle BWR Boiling Water Reactor CCNPP Calvert Cliffs Nuclear Power Plant CE Combustion Engineering CEA Control Element Assembly CEAD Control Element Assembly Drop CEDM Control Element Drive Mechanism CHF Critical Heat Flux COLR Core Operating Limits Report CRS Containment Radiation Signal CVCS Chemical and Volume Control System DNB Departure from Nucleate Boiling DNBR Departure from Nucleate Boiling Ratio ECCS Emergency Core Cooling System EOC End of Cycle EOFPC End of Full Power Capability EOL End of Life EOP Emergency Operating Procedure ESF Emergency Safety Feature FCM Fuel Centerline Melt FQ Total Power Peaking Factor FrT Total Integrated Radial Peaking Factor For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page x Acronym Definition FTC Fuel (Doppler) Temperature Coefficient FW Feedwater FWLB Feedwater Line Break HFP Hot Full Power HMP High Mechanical Performance HPSI High Pressure Safety Injection HTP High Thermal Performance HZP Hot Zero Power ICI Incore Instrumentation ISF Increase in Steam Flow LAR License Amendment Request LBLOCA Large Break Loss-of-Coolant Accident LCO Limiting Condition for Operation LHGR Linear Heat Generation Rate LHR Linear Heat Rate LOCA Loss-of-Coolant Accident LOCF Loss of Coolant Flow LOOP Loss of Offsite Power LPD Local Power Density LSSS Limiting Safety System Setting LTA Lead Test Assembly MDNBR Minimum Departure from Nucleate Boiling Ratio MFW Main Feedwater MOC Middle of Cycle MRR Most Reactive Rod MSIV Main Steam Isolation Valve MSLB Main Steam Line Break MSSV Main Steam Safety Valve MTC Moderator Temperature Coefficient NI Nuclear Instrumentation NRC Nuclear Regulatory Commission NSSS Nuclear Steam Supply System PA Postulated Accident PCT Peak Cladding Temperature PDIL Power Dependent Insertion Limit For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page xi Acronym Definition PLHR Peak Linear Heat Rate PORV Power-Operated Relief Valve PSV Pressurizer Safety Valve PTS Pressurized Thermal Shock PWR Pressurized Water Reactor PZR Pressurizer RAI Request for Additional Information RCCA Rod Cluster Control Assembly RCP Reactor Coolant Pump RCS Reactor Coolant System RHR Residual Heat Removal RLBLOCA Realistic Large Break Loss-of-Coolant Accident RPD Relative Power Density RPS Reactor Protection System RTD Resistance Temperature Device RTP Rated Thermal Power RV Reactor Vessel SAFDL Specified Acceptable Fuel Design Limit SBFP Standby Motor-driven Feedwater Pump SBLOCA Small Break Loss-of-Coolant Accident SBO Station Blackout SDC Shutdown Cooling SG Steam Generator SGTP Steam Generator Tube Plugging SI Safety Injection SIAS Safety Injection Actuation Signal SIT Safety Injection Tank SRP Standard Review Plan TH Thermal Hydraulics TM/LP Thermal Margin/Low Pressure UCBW Uncontrolled Control Bank Withdrawal UFSAR Updated Final Safety Analysis Report USNRC United States Nuclear Regulatory Commission VHP(T)

Variable High Power (Trip)

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 1-1

1.0 INTRODUCTION

This report describes the analyses which support normal operation of Calvert Cliffs Unit 2 with a lead test assembly (LTA) up to Rated Thermal Power during Cycle 26 for the CEA Rod Swap Redesign. The report describes the evaluation of the neutronic and thermal-hydraulic characteristics of the core, and the review of the SRP Chapter 15 events (Reference 1).

The analyses of the core design and identified plant changes were performed utilizing NRC approved methodologies in accordance with Framatome Inc. Quality Assurance procedures. The plant licensing bases which affect the analyses (as reflected in the applicable sections of the Technical Specifications and Bases, and in Chapter 14 of the UFSAR) were used to establish the licensing commitments and plant-specific acceptance criteria.

The Calvert Cliffs Unit 2 Cycle 26 core design includes an LTA, an accident tolerant fuel assembly that contains Framatome PROtectTM* Chromia doped UO2 pellets and Chromium coated cladding.

The analyses supporting the Safety Analysis Report were performed based on the model that includes the LTA.

The Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign swaps the group assignments for CEA 36 (core location L-19) and adjacent CEA 60 (core location J-20) such that CEA 36 is part of Regulating Group 1 and CEA 60 is part of Regulating Group 5. The analyses supporting the Safety Analysis Report were performed based on the model that includes this change in CEA group assignments. To fully evaluate and capture any imbalance or non-symmetrical variation of the core power in one quadrant of the core relative to others because of the CEA Rod Swap configuration (i.e., core tilt), all analyses were performed with full-core geometry. This ensures that any core imbalance introduced by the CEA Rod Swap Redesign is fully incorporated by the analyses and included in the results. Because Unit 2 Cycle 26 has already begun operation with the original CEA configuration, some BOC reload issues were not re-analyzed for the CEA Rod Swap Redesign. The original CCL2-26 design analyses remain valid for Unit 2 Cycle 26 at burnups prior to the CEA Rod Swap.

This report is only valid for Unit 2 Cycle 26 with the CEA Rod Swap configuration. If the original CEA configuration is restored during Unit 2 Cycle 26, Calvert Cliffs must engage Framatome

  • PROtect is a registered trademark of Framatome Inc.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 1-2 Fuel to reassess the validity of the licensing basis prior to a return to power. Reassessment will be based on actual operating history of the plant up to shutdown, including CEA group positions.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 2-1 2.0

SUMMARY

The Calvert Cliffs Unit 2 Cycle 26 (CCL2-26) reload consists of 14x14 Advanced CE HTPTM fuel assemblies supplied by Framatome Inc. The fuel assemblies contain various loadings of gadolinium oxide as a burnable absorber to control power peaking and excess reactivity. The Framatome Inc.

fuel design contains M5* fuel rods, 8 HTPTM spacers, 1 HMPTM spacer at the lowest grid location, MONOBLOC§ guide tubes and a FUELGUARD** debris-resistant lower tie plate. The CCL2-26 fuel design continues to utilize the long-dimple HTP grid design improvement introduced in the previous cycle. The core for CCL2-26 also includes one LTA, an accident tolerant fuel assembly, which uses Framatome PROtectTM Chromia-doped UO2 pellets and Chromium-coated cladding.

Blanket UO2 pellets and Gadolinia (UO2-Gd2O3) fuel pellets are not Chromia-doped.

The following areas were evaluated to support the reload: mechanical design analysis, neutronics analysis, thermal-hydraulic analysis, setpoints verification, and SRP Chapter 15 safety analyses.

The results of each of these evaluations are summarized in the sections which follow. Plant operating restrictions are implemented for Unit 2 Cycle 26 with the CEA Swap (see Section 4.4).

The mechanical design and evaluation of the Framatome Inc. fuel is presented in a separate report.

The characteristics of the fuel and the reload core were verified to be in conformance with the Technical Specification and Core Operating Limits Report (COLR) as proposed for the CEA Rod Swap Redesign.

M5 is a registered trademark of Framatome Inc.

HTP is a trademark of Framatome Inc.

HMP is a trademark of Framatome Inc.

§ MONOBLOC is a trademark of Framatome Inc.

PROtect is a trademark of Framatome Inc.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 2-2 A review of the SRP Chapter 15 and several non-Chapter 15 safety analyses was performed with respect to plant configuration, operating conditions, fuel design characteristics, Technical Specifications, and neutronics changes (The SRP Chapter 15 events are described in Chapter 14 of the UFSAR). The review identified if any re-analysis was required as a result of cycle-by-cycle variations or relevant changes identified in Section 5.1. The event review and safety analyses are reported in Section 5.0.

Section 6.0 provides discussion with respect to the verification of the Reactor Protection System (RPS) setpoints.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-1 3.0 DESIGN DESCRIPTION 3.1 General Core Description The fuel inventory is summarized in Table 3-1.

A low radial leakage fuel management plan is utilized. The fresh fuel is scatter-loaded throughout the core in a manner designed to minimize power peaking. The exposed fuel is also scatter-loaded in a manner that controls power peaking and minimizes the effects of large exposure gradients across individual assemblies. The loading pattern is shown in Figure 3-1. This figure indicates the assembly identification number at each core location and the previous cycle location for partially depleted fuel. Figure 3-1 and Figure 3-4 provide the assembly type, which is used to describe the fresh fuel assembly loading provided in Figure 3-2. The core design uses low enriched axial blankets to improve fuel economy.

3.2 Mechanical Design The mechanical design of all Framatome Inc. fuel assemblies to be operated in the core for Unit 2 Cycle 26 has been evaluated. There is no change for the CEA Rod Swap Redesign. The evaluation is summarized in a separate report.

3.3 Nuclear Design A listing of general neutronics parameters is included in Table 3-2, with a comparison to the original CCL2-26 cycle design.

The COLR and Technical Specifications will require the ARO MTC to meet the limits specified in Table 3-2. These limits are unchanged from the original CCL2-26 cycle design.

Group assignments are swapped for CEA 36 and CEA 60. The COLR rod insertion limits for the regulating banks are unchanged from the original CCL2-26 cycle design. The Technical Specification fully withdrawn position of all CEAs is supported.

The allowable time to restore CEA alignment, for a single misaligned CEA, is shown in Figure 3-3.

Predictions of FrT support the COLR FrT limit as specified in Table 4-1, including a 5% design margin allowance. Assembly relative power densities at BOC (100 MWd/MTU), MOC and EOC are presented in Figure 3-5 through Figure 3-7, and rodded (Bank 5 at the PDIL) relative power densities at BOC and EOC are presented in Figure 3-8 and Figure 3-9.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-2 Predictions of LHR support the COLR LHR limit as specified in Table 4-1, and include a 7% FQ measurement uncertainty, a 3% engineering uncertainty, a 2% allowance for power measurement uncertainty for power > 50% RTP, and a 3.5% power measurement uncertainty for power 50%

RTP.

An increase in the azimuthal power tilt is predicted when the asymmetric group 5 bank is inserted.

Core power distribution surveillance in accordance with Technical Specifications will continue to ensure adherence to LHR and FrT limits in the presence of an increased azimuthal power tilt.

Detailed calculations of shutdown margin are provided in Table 3-3. The COLR shutdown margin requirements for Modes 3, 4, and 5 remain unchanged from the original CCL2-26 cycle design.

The LTA meets the [

] lower in peak pin power than the peak pin power co-resident fuel criterion throughout the cycle.

Radial maps of the BOC and EOC assembly average burnups are presented in Figure 3-10 and Figure 3-11, respectively.

In summary, the neutronic characteristics of the fuel and the reload core support the current Technical Specifications and proposed COLR limits, and were evaluated utilizing NRC approved methodologies (References 2 and 13) and criteria in accordance with Framatome Inc. Quality Assurance procedures.

3.4 Thermal-Hydraulic Design The thermal-hydraulic performance of the core under postulated transient and accident conditions is addressed in Section 5.0. Thermal-hydraulic limits are presented in Table 3-4.

The thermal-hydraulic characteristics of the fuel and the reload core support the current Technical Specifications and proposed COLR limits, and were evaluated utilizing NRC approved methodologies (References 4, 10, 11, 12, 14 and 20) and criteria in accordance with Framatome Inc. Quality Assurance procedures.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-3 Table 3-1 Fuel Inventory Characteristics Fuel Type Number of Assemblies Initial Cycle Number Initial Enrichments (w/o)

Initial Gd2O3 Loading (w/o)

BG1 40 U2C26 4.33 / 4.92 / 1.60 ( 3.40 / 3.90 )

4.0 / 6.0 BG2 16 4.33 / 4.92 / 1.60 ( 3.90 / 3.40 )

4.0 / 6.0 BG3 20 4.33 / 4.92 / 1.60 ( 3.90 )

4.0 BG4 20 4.33 / 4.92 / 1.60 ( 3.90 )

4.0 BF1 44 U2C25 4.33 / 4.94 / 2.00 ( 3.40 / 3.90 )

4.0 / 6.0 BF2 12 4.33 / 4.94 / 2.00 ( 3.40 / 3.90 )

4.0 / 6.0 BF3 20 4.33 / 4.94 / 2.00 ( 3.90 )

4.0 BF4 20 4.33 / 4.94 / 2.00 ( 3.90 )

4.0 BE3 1

U2C24 4.87 / 4.27 / 1.60 ( 3.20 / 2.90 )

6.0 / 8.0 BE4 4

4.87 / 4.27 / 1.60 ( 3.20 )

6.0 BE5 15 4.87 / 4.27 / 1.60 ( 4.27 )

2.0 BE6*

1 4.87 / 4.27 / 1.60 ( 4.27 )

2.0 BD4 4

U2C23 4.91 / 4.33 / 1.60 ( 3.60 )

5.0 Lead Test Assembly For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-4 Table 3-2 Neutronics Characteristics For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-5 Table 3-3 Shutdown Margin Unit 2 Cycle 26 CEA Rod Swap BOC2 EOC HZP HFP HZP HFP[1]

Control Rod Worth (pcm)

ARI 7348.8 7380.5 8522.1 8326.6 MRR 1188.6 1210.4 1456.0 1468.1 PDIL 1567.9 131.4 1899.7 169.9 (ARI-MRR-PDIL)*0.9 4133.1 5434.9 4649.7 6019.8 Positive Reactivity Insertion (pcm)

Power Defect 0.0 1056.5 0.0 2225.0 Axial Flux Redistribution 0.0 62.5 0.0 176.2 Coolant Void Effects 0.0 50.0 0.0 50.0 Total Positive Reactivity Insertion 0.0 1169.0 0.0 2451.2 Shutdown Margin (pcm)

(ARI-MRR-PDIL)*0.9 - Total Positive Reactivity Insertion 4133.1 4265.9 4649.7 3568.6 Required Shutdown Margin 3500.0 3500.0 3500.0 3500.0 Excess Shutdown Margin 633.1 765.9 1149.7 68.6 Original Unit 2 Cycle 26 BOC EOC HZP HFP HZP HFP[1]

Control Rod Worth (pcm)

ARI 7348.4 7383.6 8522.1 8320.0 MRR 1181.8 1204.9 1456.0 1468.0 PDIL 1611.9 142.8 1901.8 179.1 (ARI-MRR-PDIL)*0.9 4099.3 5432.3 4647.9 6005.7 Positive Reactivity Insertion (pcm)

Power Defect 0.0 1058.4 0.0 2218.4 Axial Flux Redistribution 0.0 81.2 0.0 183.4 Coolant Void Effects 0.0 50.0 0.0 50.0 Total Positive Reactivity Insertion 0.0 1189.6 0.0 2451.8 Shutdown Margin (pcm)

(ARI-MRR-PDIL)*0.9 - Total Positive Reactivity Insertion 4099.3 4242.7 4647.9 3553.9 Required Shutdown Margin 3500.0 3500.0 3500.0 3500.0 Excess Shutdown Margin 599.3 742.7 1147.9 53.9

[1] The values reported are at End-of-Full-Power-Capability (EOFPC).

[2] BOC values are only provided herein as representative statepoints since the reactor will enter the CEA Rod Swap configuration beyond BOC.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-6 Table 3-4 Thermal-Hydraulic Limits Parameter Unit 2 Cycle 26 CEA Rod Swap Original Unit 2 Cycle 26 LHGR Limit (kW/ft)

[

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[

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)XHO&HQWHUOLQH0HOW7HPSHUDWXUH )

4595 4595 HTP Correlation Limit

[

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[

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Mixed-Core CHF Penalty

[

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[

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Fuel Rod Bow DNBR Penalty

[

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[

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LHGR Penalty

[

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[

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  • [

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For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-7 Fresh Fuel Type Number of Assemblies Assembly Numbers Central Zone U-235 Enrichment Gadolinia Loading BG1 40 BG101-BG140 4.92 CZE

SLQVZLWKZR*G2SLQVZLWKZR*G2

BG2 16 BG201-BG216 4.92 CZE

SLQVZLWKZR*G2SLQVZLWKZR*G2

BG3 20 BG301-BG320 4.92 CZE 12 pins with 4w/o Gd2O3 BG4 20 BG401-BG420 4.92 CZE 8 pins with 4w/o Gd2O3 Total:

96 Figure 3-1 Full Core Loading Pattern For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-8 Sub-Batch: BG1 Type

  1. Rods U235 %

Gd2O3 %

11 52 4.33 1

104 4.92 6

12 3.40 6

4 8

3.90 4

Sub-Batch: BG2 Type

  1. Rods U235 %

Gd2O3 %

11 52 4.33 1

108 4.92 4

8 3.90 4

6 8

3.40 6

Figure 3-2 Fuel Rod Assembly Lattices For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-9 Sub-Batch: BG3 Type

  1. Rods U235 %

Gd2O3 %

11 52 4.33 1

112 4.92 4

12 3.90 4

Sub-Batch: BG4 Type

  1. Rods U235 %

Gd2O3 %

11 52 4.33 1

116 4.92 4

8 3.90 4

Figure 3-2 Fuel Rod Assembly Lattices For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-10 UO2 Rod Layouts 136.7" 11 1

130.7" Blanket 1.60 1.60 124.7" Cutback 4.33 4.92 12.0" Central 6.0" Cutback 0.0" Blanket 1.60 1.60 Gadolinia Rod Layouts 4

6 136.7" 130.7" Blanket 1.60 1.60 124.7" Cutback 12.0" Central 3.90 4.0 w/o Gd2O3 3.40 6.0 w/o Gd2O3 6.0" Cutback 1.60 1.60 0.0" Blanket Figure 3-2 Fuel Rod Assembly Lattices For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-11 Figure 3-3 Allowable time to Realign CEA Versus Initial Total Radial Peaking Factor (FrT)

-10 0

10 20 30 40 50 60 70 80 90 100 110 120 130 1.60 1.61 1.62 1.63 1.64 1.65 1.66 Measured Pre-Misaligned Total Integrated Radial Peaking Factor, FrT Time to Realign CEA (minutes)

Acceptable Operation (1.66, 0)

(1.65, 120)

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-12 X

Y X - Box Number Y - Batch 1

BE5 2

BF1 3

BE4 4

BF1 5

BF1 6

BG4 7

BG3 8

BE5 9

BG4 10 BG3 11 BG3 12 BF4 13 BF3 14 BE5 15 BG4 16 BF4 17 BG1 18 BF1 19 BG1 20 BF4 21 BD4 22 BG4 23 BF4 24 BG2 25 BF2 26 BG1 27 BF3 28 BG1 29 BF1 30 BG3 31 BG1 32 BF2 33 BG1 34 BF3 35 BG1 36 BF1 37 BF1 38 BG3 39 BF1 40 BG1 41 BF3 42 BG2 43 BF1 44 BG2 45 BE6 46 BG4 47 BF4 48 BG1 49 BF3 50 BG1 51 BF1 52 BG2 53 BF1 54 BF2 55 BG3 56 BF3 57 BF4 58 BG1 59 BF1 60 BG2 61 BF1 62 BE3 Figure 3-4 Quarter-Core Assembly Map*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 45).

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-13 X

Y XXX X - Box Number Y - Batch XXX - Assembly Relative Power Density 1

BE5 0.261 2

BF1 0.450 3

BE4 0.256 4

BF1 0.487 5

BF1 0.677 6

BG4 1.153 7

BG3 1.211 8

BE5 0.340 9

BG4 0.961 10 BG3 1.180 11 BG3 1.285 12 BF4 1.204 13 BF3 1.200 14 BE5 0.339 15 BG4 1.001 16 BF4 1.116 17 BG1 1.230 18 BF1 1.091 19 BG1 1.255 20 BF4 1.214 21 BD4 0.251 22 BG4 0.955 23 BF4 1.110 24 BG2 1.284 25 BF2 1.081 26 BG1 1.211 27 BF3 1.131 28 BG1 1.258 29 BF1 0.483 30 BG3 1.175 31 BG1 1.229 32 BF2 1.091 33 BG1 1.211 34 BF3 1.108 35 BG1 1.231 36 BF1 1.103 37 BF1 0.667 38 BG3 1.279 39 BF1 1.092 40 BG1 1.215 41 BF3 1.115 42 BG2 1.281 43 BF1 1.104 44 BG2 1.280 45 BE6 0.249 46 BG4 1.144 47 BF4 1.201 48 BG1 1.260 X

49 BF3 1.135 50 BG1 1.233 51 BF1 1.107 52 BG2 1.272 53 BF1 1.069 54 BF2 0.446 55 BG3 1.210 56 BF3 1.200 57 BF4 1.214 58 BG1 1.258 59 BF1 1.104 60 BG2 1.282 61 BF1 1.073 62 BE3 1.046 Long N-1 Burnup (22.080 GWd/MTU) Note: X = Maximum Fr Value = 1.542 Figure 3-5 Assembly Relative Power Density at BOC (100 MWd/MTU), HFP, ARO, Equilibrium Xenon*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 45).

This figure is only provided herein as a representative statepoint since the reactor will enter the CEA Rod Swap configuration beyond BOC.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-14 X

Y XXX X - Box Number Y - Batch XXX - Assembly Relative Power Density 1

BE5 0.228 2

BF1 0.381 3

BE4 0.260 4

BF1 0.472 5

BF1 0.598 6

BG4 0.973 7

BG3 1.040 8

BE5 0.331 9

BG4 0.954 10 BG3 1.222 11 BG3 1.249 12 BF4 1.004 13 BF3 0.963 14 BE5 0.331 15 BG4 0.957 16 BF4 1.047 17 BG1 1.383 18 BF1 1.065 19 BG1 1.338 20 BF4 1.104 21 BD4 0.258 22 BG4 0.952 23 BF4 1.043 24 BG2 1.373 25 BF2 1.097 26 BG1 1.409 27 BF3 1.141 28 BG1 1.425 29 BF1 0.471 30 BG3 1.221 31 BG1 1.384 32 BF2 1.107 33 BG1 1.418 34 BF3 1.136 35 BG1 1.421 36 BF1 1.114 37 BF1 0.593 38 BG3 1.247 39 BF1 1.067 40 BG1 1.413 41 BF3 1.141 42 BG2 1.409 43 BF1 1.076 44 BG2 1.366 45 BE6 0.219 46 BG4 0.969 47 BF4 1.004 48 BG1 1.343 49 BF3 1.143 50 BG1 1.422 X

51 BF1 1.078 52 BG2 1.311 53 BF1 0.973 54 BF2 0.379 55 BG3 1.039 56 BF3 0.963 57 BF4 1.104 58 BG1 1.425 59 BF1 1.114 60 BG2 1.367 61 BF1 0.975 62 BE3 0.913 Long N-1 Burnup (22.080 GWd/MTU) Note: X = Maximum Fr Value = 1.536 Figure 3-6 Assembly Relative Power Density at HFP, ARO, Equilibrium Xenon (10,000 MWd/MTU)*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 45).

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-15 X

Y XXX X - Box Number Y - Batch XXX - Assembly Relative Power Density 1

BE5 0.333 2

BF1 0.529 3

BE4 0.345 4

BF1 0.576 5

BF1 0.714 6

BG4 1.110 7

BG3 1.174 8

BE5 0.426 9

BG4 1.036 10 BG3 1.216 11 BG3 1.244 12 BF4 1.053 13 BF3 1.028 14 BE5 0.426 15 BG4 1.045 16 BF4 1.053 17 BG1 1.309 18 BF1 1.037 19 BG1 1.287 20 BF4 1.079 21 BD4 0.345 22 BG4 1.036 23 BF4 1.050 24 BG2 1.295 25 BF2 1.042 26 BG1 1.296 27 BF3 1.067 28 BG1 1.300 29 BF1 0.576 30 BG3 1.216 31 BG1 1.309 X

32 BF2 1.048 33 BG1 1.291 34 BF3 1.051 35 BG1 1.286 36 BF1 1.034 37 BF1 0.709 38 BG3 1.243 39 BF1 1.037 40 BG1 1.297 41 BF3 1.054 42 BG2 1.275 43 BF1 1.013 44 BG2 1.262 45 BE6 0.322 46 BG4 1.106 47 BF4 1.052 48 BG1 1.288 49 BF3 1.068 50 BG1 1.285 51 BF1 1.015 52 BG2 1.241 53 BF1 0.964 54 BF2 0.526 55 BG3 1.174 56 BF3 1.028 57 BF4 1.079 58 BG1 1.300 59 BF1 1.034 60 BG2 1.262 61 BF1 0.964 62 BE3 0.937 Long N-1 Burnup (22.080 GWd/MTU) Note: X = Maximum Fr Value = 1.384 Figure 3-7 Assembly Relative Power Density at EOC, HFP, ARO, Equilibrium Xenon*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 45).

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-16 Long N-1 Burnup (22.080 GWd/MTU) Note: X = Maximum Fr Value = 1.583 (Box 177)

Figure 3-8 Assembly Relative Power Density with Bank 5 Inserted to PDIL at BOC (100 MWd/MTU) HFP, Equilibrium Xenon*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 83).

CCL2-26 CEA Rod Swap Redesign is not quarter core symmetric with Bank 5 inserted. Full core map is provided.

This figure is only provided herein as a representative statepoint since the reactor will enter the CEA Rod Swap configuration beyond BOC.

X - Box Number XXX Y

X XXX - Assembly Relative Power Density Y - Batch BE5 BF2 BF1 BE5 0.222 0.408 0.434 0.259 214 215 216 217 0.502 0.266 BF1 BF1 BE4 0.254 0.479 0.628 0.989 1.153 1.144 0.687 210 211 212 213 BD4 BF1 BF1 BG4 BG3 BG4 205 206 207 208 209 1.218 0.997 0.353 BG4 BE5 0.347 0.973 1.181 1.257 1.156 1.177 1.211 1.314 204 BE5 BG4 BG3 BG3 BF4 BF3 BF4 BG3 BG3 198 199 200 201 202 203 194 195 196 197 1.037 0.351 1.264 1.224 1.279 1.122 1.272 1.158 BF1 BG1 BF4 BG4 BE5 0.348 1.027 1.136 1.250 1.100 192 193 BE5 BG4 BF4 BG1 BF1 BG1 BF4 BG1 186 187 188 189 190 191 181 182 183 184 185 X

0.257 1.163 1.250 1.118 1.328 1.144 0.980 BG4 BD4 0.261 0.981 1.144 1.317 1.118 1.242 1.158 1.287 BG1 BF3 BG1 BF2 BG2 BF4 178 179 180 BE4 BG4 BF4 BG2 BF2 BG1 BF3 172 173 174 175 176 177 166 167 168 169 170 171 1.144 1.250 1.122 1.254 1.190 0.486 BF1 0.488 1.191 1.249 1.104 1.243 1.145 1.267 1.136 1.269 BG1 BF3 BG1 BF2 BG1 BG3 164 165 BF1 BG3 BG1 BF2 BG1 BF3 BG1 BF1 158 159 160 161 162 163 151 152 153 154 155 156 157 1.094 1.266 0.653 1.137 1.315 1.135 1.318 1.143 1.236 BF1 BG3 BF1 0.661 1.269 1.090 1.228 1.134 1.316 BF1 BG2 BF1 BG2 BF3 BG1 149 150 0.238 BF1 BG3 BF1 BG1 BF3 BG2 143 144 145 146 147 148 BE5 0.249 136 137 138 139 140 141 142 BE5 1.140 1.231 1.138 1.084 135 1.131 1.299 1.088 1.295 1.133 1.257 BG1 BF4 BG4 134 1.091 1.138 1.225 1.135 1.254 BG2 BF1 BG2 BF1 BG1 BF3 132 133 0.420 BG4 BF4 BG1 BF3 BG1 BF1 126 127 128 129 130 131 BF2 0.423 119 120 121 122 123 124 125 BF1 1.256 1.162 1.033 1.121 118 1.310 1.091 1.018 1.083 1.307 1.121 BF3 BG3 117 1.120 1.032 1.160 1.255 1.121 BE3 BF1 BG2 BF1 BG1 BF4 0.424 BG3 BF3 BF4 BG1 BF1 BG2 BF1 111 112 113 114 115 116 105 106 107 108 109 110 BF1 0.420 102 103 104 1.139 1.092 101 BF2 1.087 1.292 1.127 1.252 1.135 1.225 BG4 100 1.082 1.135 1.228 1.136 1.254 1.131 1.297 BG2 BF1 BG1 BF3 BG1 BF4 0.249 BG4 BF4 BG1 BF3 BG1 BF1 BG2 BF1 94 95 96 97 98 99 88 89 90 91 92 93 BE5 0.238 85 86 87 1.269 0.661 84 BE6 1.306 1.129 1.309 1.130 1.226 1.089 BG3 BF1 83 0.650 1.260 1.089 1.229 1.136 1.310 1.128 BG2 BF1 BG2 BF3 BG1 BF1 80 81 82 BF1 BG3 BF1 BG1 BF3 BG2 BF1 74 75 76 77 78 79 68 69 70 71 72 73 1.136 1.238 1.103 1.248 1.190 0.488 BF1 0.484 1.182 1.245 1.111 1.236 1.129 1.250 1.119 1.252 BG1 BF3 BG1 BF2 BG1 BG3 66 67 BF1 BG3 BG1 BF2 BG1 BF3 BG1 BF1 60 61 62 63 64 65 53 54 55 56 57 58 59 1.143 0.980 0.260 1.132 1.253 1.136 1.230 1.113 1.315 BG2 BF4 BG4 BE4 0.255 0.972 1.132 1.311 1.100 1.224 BG1 BF3 BG1 BF3 BG1 BF2 48 49 50 51 52 BD4 BG4 BF4 BG2 BF2 42 43 44 45 46 47 38 39 40 41 1.026 0.348 1.223 1.159 1.228 1.089 1.247 1.134 BF1 BG1 BF4 BG4 BE5 0.347 1.024 1.139 1.245 1.087 36 37 BE5 BG4 BF4 BG1 BF1 BG1 BF4 BG1 30 31 32 33 34 35 25 26 27 28 29 1.136 1.262 1.184 0.974 0.347 BG3 BG3 BG4 BE5 0.347 0.978 1.188 1.266 1.137 1.032 22 23 24 BE5 BG4 BG3 BG3 BF4 BF3 BF4 14 15 16 17 18 19 20 21 0.484 0.255 BF1 BF1 BD4 0.260 0.487 0.660 1.090 1.120 1.083 0.651 10 11 12 13 BE4 BF1 BF1 BG4 BG3 BG4 5

6 7

8 9

BE5 0.249 0.423 0.420 0.237 1

2 3

4 BE5 BF1 BF2 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-17 Long N-1 Burnup (22.080 GWd/MTU) Note: X = Maximum Fr Value = 1.421 (Box 190)

Figure 3-9 Assembly Relative Power Density with Bank 5 Inserted to PDIL at EOC, HFP, Equilibrium Xenon*

CCL2-26 is not quarter core symmetric. The LTA is in location A-8 (Box 83).

CCL2-26 CEA Rod Swap Redesign is not quarter core symmetric with Bank 5 inserted. Full core map is provided.

0.283 0.474 0.504 0.328 214 215 216 217 BE5 BF2 BF1 BE5 0.589 0.356 BF1 BF1 BE4 0.347 0.567 0.659 0.933 1.100 1.090 0.720 210 211 212 213 BD4 BF1 BF1 BG4 BG3 BG4 205 206 207 208 209 1.264 1.246 1.067 0.440 BG3 BG4 BE5 0.434 1.048 1.214 1.211 1.001 0.999 1.052 203 204 BE5 BG4 BG3 BG3 BF4 BF3 BF4 BG3 194 195 196 197 198 199 200 201 202 X

1.345 1.086 1.077 0.439 BE5 0.435 1.066 1.068 1.323 1.039 1.286 1.084 1.306 1.060 BF4 BG1 BF1 BG1 BF4 BG4 BE5 BG4 BF4 BG1 BF1 BG1 188 189 190 191 192 193 181 182 183 184 185 186 187 1.332 1.072 1.331 1.077 1.059 0.352 BD4 0.351 1.053 1.074 1.320 1.067 1.319 1.085 1.324 1.093 BF3 BG1 BF2 BG2 BF4 BG4 179 180 BE4 BG4 BF4 BG2 BF2 BG1 BF3 BG1 173 174 175 176 177 178 166 167 168 169 170 171 172 1.081 1.327 1.073 1.332 1.229 0.580 BF1 0.578 1.225 1.326 1.061 1.319 1.078 1.317 1.061 1.321 BG1 BF3 BG1 BF2 BG1 BG3 164 165 BF1 BG3 BG1 BF2 BG1 BF3 BG1 BF1 158 159 160 161 162 163 151 152 153 154 155 156 157 1.318 1.041 1.233 0.697 1.306 1.040 1.294 1.041 1.310 1.079 BG1 BF1 BG3 BF1 0.700 1.231 1.037 1.313 1.072 BG2 BF1 BG2 BF1 BG2 BF3 BF1 BG3 BF1 BG1 BF3 146 147 148 149 150 0.310 140 141 142 143 144 145 BE5 0.320 136 137 138 139 BE5 1.311 1.074 1.264 0.999 1.053 135 1.308 1.036 1.266 0.980 1.267 1.039 BF3 BG1 BF4 BG4 134 1.055 0.998 1.261 1.072 BF1 BG2 BF1 BG2 BF1 BG1 BG4 BF4 BG1 BF3 BG1 129 130 131 132 133 0.500 123 124 125 126 127 128 BF2 0.502 119 120 121 122 BF1 1.051 1.301 1.038 0.880 1.091 118 1.050 1.288 0.980 0.908 0.978 1.289 BG1 BF4 BF3 BG3 117 1.090 0.879 1.036 1.299 BG2 BF1 BE3 BF1 BG2 BF1 BG3 BF3 BF4 BG1 BF1 112 113 114 115 116 0.502 106 107 108 109 110 111 BF1 0.499 102 103 104 105 BF2 1.308 1.072 1.261 0.999 1.056 101 1.307 1.036 1.264 0.978 1.264 1.035 BF3 BG1 BF4 BG4 100 1.051 0.998 1.261 1.071 BF1 BG2 BF1 BG2 BF1 BG1 BG4 BF4 BG1 BF3 BG1 95 96 97 98 99 0.321 89 90 91 92 93 94 BE5 0.310 85 86 87 88 1.037 1.232 0.701 84 BE6 1.034 1.287 1.036 1.303 1.072 1.313 BF1 BG3 BF1 83 0.695 1.230 1.037 1.312 1.074 1.303 BF1 BG2 BF1 BG2 BF3 BG1 BF1 BG3 BF1 BG1 BF3 BG2 77 78 79 80 81 82 68 69 70 71 72 73 74 75 76 1.226 0.578 1.049 1.307 1.074 1.317 1.061 1.326 BG1 BG3 BF1 0.578 1.225 1.326 1.067 1.317 1.071 1.306 BG1 BF1 BG1 BF3 BG1 BF2 BF1 BG3 BG1 BF2 BG1 BF3 62 63 64 65 66 67 53 54 55 56 57 58 59 60 61 1.054 0.351 1.299 1.071 1.312 1.067 1.321 1.075 BF4 BG4 BE4 0.351 1.054 1.071 1.321 1.061 1.312 1.071 BF3 BG1 BF3 BG1 BF2 BG2 49 50 51 52 BD4 BG4 BF4 BG2 BF2 BG1 43 44 45 46 47 48 38 39 40 41 42 1.068 0.435 1.260 1.036 1.261 1.037 1.326 1.070 BF1 BG1 BF4 BG4 BE5 0.436 1.068 1.074 1.326 1.037 36 37 BE5 BG4 BF4 BG1 BF1 BG1 BF4 BG1 30 31 32 33 34 35 25 26 27 28 29 0.879 0.998 1.230 1.225 1.054 0.436 BF4 BG3 BG3 BG4 BE5 0.436 1.054 1.225 1.231 0.998 21 22 23 24 BE5 BG4 BG3 BG3 BF4 BF3 14 15 16 17 18 19 20 BD4 0.351 0.578 0.700 1.055 1.090 1.052 0.695 0.578 0.351 12 13 BE4 BF1 BF1 BG4 BG3 BG4 BF1 BF1 5

6 7

8 9

10 11 XXX XXX - Assembly Relative Power Density 0.321 0.502 0.499 0.310 Y

Y - Batch BE5 BF1 BF2 BE5 X

X - Box Number 1

2 3

4 For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-18 Figure 3-10 Assembly Average Burnup at BOC*

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 3-19 Figure 3-11 Assembly Average Burnup at EOC*

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For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 4-1 4.0 PLANT OPERATING CONDITIONS 4.1 Plant Characteristics and Initial Conditions The following operational modes have been considered in the analyses:

Mode Reactivity Condition, keff

% Rated Thermal Power Average Reactor Coolant Temperature (°F)

(1) Power Operation 0.99

> 5 N/A (2) Startup 0.99

5 N/A (3) Hot Standby



0 300 (4) Hot Shutdown



0

7avg 

(5) Cold Shutdown



0 200 (6) Refueling N/A 0

N/A Note1: Plant operating restrictions are implemented for Unit 2 Cycle 26 with the CEA Swap (see Section 4.4).

These six operational modes have been considered in establishing the sub-events associated with each event initiator. A set of initial conditions is established for the events analyzed that is consistent with the conditions for each mode of operation.

The plant operating conditions and uncertainties supported are presented in Table 4-1.

4.2 Effects of Fuel Rod Bowing Fuel Rod Bow penalties were verified in accordance with Framatome Inc. rod bow methodology (Reference 12).

4.3 Radiological Analysis The radiological analysis is outside of the Framatome Inc. scope. Constellation is responsible for assessing the applicability of the AOR.

4.4 Plant Operating Restrictions for Unit 2 Cycle 26 with CEA Swap Calvert Cliffs is imposing the following plant operating restrictions for Unit 2 Cycle 26:

a. Restriction #1 - Operation in Mode 2 is limited to Power > 1% RTP. If operation drops to 1% RTP, the plant will continue to Mode 3 and follow restriction #2.
b. Restriction #2 - Operation into any shutdown Mode 3/4/5 will result in fixing the stuck rod with the original CEA configuration prior to starting up.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 4-2 These plant operating restrictions were a result of the Uncontrolled CEA Withdrawal from Subcritical or Low Power Startup Condition event described in Section 5.2.4.1. Specifically, operation in Mode 2 with the CEA Swap configuration and Power 1% RTP is not supported by this SAR.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 4-3 Table 4-1 General Core Parameters and Plant Operating Conditions Parameter Value Peaking Factor, FrT: COLR Limit at Rated Thermal Power (RTP)

Unrodded



Rodded (Bank 5 Inserted to PDIL) Augmentation Factor



PLHR: COLR Limit at Rated Thermal Power (RTP) 15.0 kW/ft ARO CEA Position (Inches Withdrawn)

LQFKHV Maximum Control Element Assembly (CEA) Insertion at HFP (Regulating Bank 5, % Inserted)



Rated Core Thermal Power 2737 MWth RCP Thermal Power (Total) 17 MWth HFP Steady State Cold Leg Temperature (maximum) 548.0 ºF Nominal Steady State Pressurizer Pressure 2200 - 2300 psia Minimum Pressurizer Pressure 2200 psia Minimum Reactor Coolant Flow 370,000 gpm Steam Generator Pressure at HFP (No Tube Plugging) 891.8 psia (BOC)

Steam Generator Pressure at HFP (10% Tube Plugging) 866.6 psia (EOL)

Steam Generator Steam Mass Flow Rate at full power 12.06 Mlbm/hr Steam Generator Feedwater Temperature 441)

Maximum Steam Generator Tube Plugging



Core Power, HFP (calorimetric) Uncertainty

+/- 0.6211%

Reactor Coolant Temperature Uncertainty

+/- 4)*

Pressurizer Pressure Uncertainty

+/- 36.0 psi Reactor Coolant Flow Uncertainty 12,480 gpm

  • Deterministically bounds Tcold RTD uncertainty with up to 3 RTDs out-of-service.

For Information Only

Framatome Inc.

ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-1 5.0 EVENT REVIEW AND ANALYSIS This section provides the results of the event disposition performed to support Unit 2 Cycle 26 operation for the CEA Rod Swap Redesign. The list of changes compared to the original Unit 2 Cycle 26 design is provided in Section 5.1 and the event review is provided in Section 5.2 along with a summary of any reanalysis if relevant.

5.1 Summary of Plant Changes The information provided in the Plant Parameters Document (Reference 16) remains unchanged for the CEA Rod Swap Redesign. All changes from the original CCL2-26 cycle design with respect to a potential impact on the AORs are presented in this section.

5.1.1 Plant-Related Changes 5.1.1.1 Plant Configuration Changes Below are the plant configuration changes relative to the original Calvert Cliffs Unit 2 Cycle 26 reload analysis. Plant changes related to the CEA swap are described in Table 5-1 and illustrated in Figure 5-1. The CEA group swap exchanges the CEA bank group assignments for CEAs at core locations L-19 and J-20. The swap is being performed to mitigate the impacts of a CEA upper gripper coil failure at core location L-19, which renders the CEA at this location trippable but not movable.

The swapping of group assignments for CEA 36 and 60 (Table 5-1) creates a minor asymmetry in the CEA group 1 and group 5 bank patterns (Figure 5-1). The CEA Regulating group 1 bank will only be inserted following a trip or when the reactor is in a subcritical state prior to entering Mode 2 from Mode 3 (Technical Specification 3.1.6). Thus, following CEA reassignment, the asymmetric CEA Group 1 bank pattern will not impact Mode 1 or 2 conditions. Following CEA swap, the CEA group 5 bank pattern can have an asymmetric influence on the Mode 1 and 2 radial power distribution when inserted. An increase in the azimuthal power tilt is predicted when the asymmetric group 5 bank is inserted (Section 3.3). Core power distribution surveillance will continue to ensure adherence to LHR and FrT limits in the presence of an increased azimuthal power tilt.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-2 With the plant operating restrictions described in Section 4.4, the listed changes have a negligible impact on the analyses of record, as the values used in the SRP Chapter 15 (UFSAR, Chapter 14) analyses are not impacted by the changes shown below, and no analysis was revised to address these changes.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-3 Table 5-1 Summary of Plant Configuration Changes Item CCL2-26 CEA Rod Swap Value Original CCL2-26 Value Bank Assignment CEA 36 (core location L-19)

CEA 60 (core location J-20)

Regulating Group 1 Regulating Group 5 Regulating Group 5 Regulating Group 1 CEA 36 (core location L-19) Mobility Fully withdrawn CEA is trippable, but not moveable Figure 5-1 CEA Bank Assignment Swap For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-4 5.1.1.2 Modes of Operation There are no relevant changes for the CEA Rod Swap Redesign.

5.1.1.3 Operating States There are no relevant changes for the CEA Rod Swap Redesign.

5.1.1.4 Operating Conditions Changes to thermal-hydraulic operating conditions for the CEA Rod Swap Redesign are identified in Table 5-1 of this document along with any plant configuration and Tech Spec operating limit changes. See Section 4.4 for plant operating restrictions for Unit 2 Cycle 26 with the CEA Swap configuration.

5.1.1.5 Probable Event Initiators There are no changes in event initiators in the CEA Rod Swap Redesign.

5.1.1.6 RPS and ESF System Functions All plant system related changes, if any, are addressed in Section 5.1.1.1.

5.1.1.7 Technical Specifications Changes (Customer Initiated)

No Technical Specification changes identified by CCNPP impact the CEA Rod Swap Redesign.

The CEA swap for Unit 2 Cycle 26 is described in Section 5.1.1.1.

5.1.2 Fuel Design Characteristics The Framatome Inc. HTP' fuel and the PROtect' accident tolerant fuel with Chromia-doped UO2 pellets and Chromium-coated cladding designs are described in Section 2.0.

5.1.3 Core Composition The Framatome Inc. core design for Unit 2 Cycle 26 is described in Section 3.1.

5.1.4 Neutronics Characteristics The Framatome Inc. safety analyses use bounding values for these parameters on an event-specific basis.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-5 5.1.5 Analytical Methodologies For the use of Framatome Inc.s USNRC-approved methodologies (References 2 through 6 and References 10 through 14), the NRC SER (Reference 15, pages 81 to 85) from the transition resulted in several analytical changes, including:

Use of a FCM LHGR Limit of 21 kW/ft.

Observance of a limit that rod internal pressure remains below steady-state system pressure.

Restriction of S-RELAP5 to safety analyses that confirm acceptable performance relative to the SAFDLs.

The impact of the changes to the plant with respect to the PSV tolerance and setpoints during Unit 1 Cycle 23 has been addressed in a separate LAR. The LAR identified analyses that replaced the previous Analysis of Record for both primary and secondary over pressure events (Reference 17).

No changes to specific COLR figures until generic analysis for power level sensitive transients is approved.

Use of a Seized Rotor TH model with reduced inlet flow factors due to asymmetric core inlet flow distribution.

Use of a revised Asymmetric SG Transient modeling (sectorized RV & core).

Use of a CEA Ejection peak radial average fuel enthalpy acceptance criteria limit of 200 cal/g.

Use of an extended zero power PDIL curve with Bank 3 fully inserted for the determination of CEA Ejection peak radial average fuel enthalpy for HZP cases.

A SBLOCA break spectrum with augmented detail relative to break size.

The SBLOCA methodology (Reference 6) listed in the SER was later supplemented through the evaluation model changes described in Reference 18, which were approved by the US-NRC in 2016. The Calvert Cliffs SBLOCA analysis with the evaluation model updates is documented in Reference 9.

Approval of ECCS modeling only for the first transition cycle. NRC approval of the analysis of once-and twice-burned fuel required for subsequent cycle core designs.

The revised ECCS modeling methodology was submitted and received NRC approval in December 2012 (References 7 and 8), however since NRC approval was obtained via For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-6 letter and not LAR, this license condition is still listed in Appendix C of the Technical Specifications and has been retained here for consistency.

The HTP CHF correlation (Reference 4) is primarily used in the DNB analyses for Calvert Cliffs.

However, in the post-scram MSLB event (SRP 15.1.5, UFSAR 14.14), the conditions are outside the range of applicability of the [

] but are within the [

] range of applicability. Therefore, the Biasi CHF correlation is used in the post-scram MSLB event for Calvert Cliffs. This is in accordance with the methodology approved in Reference 3.

SER analytical change 4 (also referred to as Licensing Condition #4 in the Safety Evaluation Report for the Transition to Framatome Fuel, Reference 15) includes reference to COLR figures.

Core operating limits on CEA Group Insertion vs power (COLR Figure 3.1.6), Total Integrated Radial Peaking Factor vs power (COLR Figure 3.2.3), and the DNB Axial Flux Offset Control Limits (COLR Figure 3.2.5) remain unchanged for the CEA Swap. While there are no changes to the CEA group rod insertion limits provided in the COLR, swapping two CEA group assignments can change the bank worth of the group to which they are assigned and the core locations of the localized reactivity change associated with CEA group movement.

The reassignment of two corner adjacent CEAs, described in Section 5.1.1.1, are explicitly modeled in the calculations of cycle-specific neutronic parameters evaluated against the bounding values used in the safety analyses. The impacts of the CEA reassignment on safety analyses were evaluated and summarized in Section 5.2. For the majority of the neutronics parameters employed in the safety analyses, introduction of the CEA Swap produces changes in these parameters comparable to the variation observed during a typical reload cycle. To ensure all existing safety analysis AOR bound the CEA Swap condition, plant operating restrictions are imposed, as discussed in Section 4.4.

There are no changes to COLR figures 3.1.6, 3.2.3, or 3.2.5, and plant operation following the CEA Swap continues to meet safety analyses acceptance criteria. Therefore, SER analytical change 4 continues to be met. The ejected rod event continues to be assessed against SER analytical change 7 and 8 criteria and event evaluation conditions.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-7 The planned CEA reassignment (or swap) is being submitted as a Licensing Amendment Request for NRC review.

5.1.6 Limiting Assumptions No changes for the CEA Rod Swap Redesign.

5.1.7 Additional Customer-Requested Changes There are no additional changes for the CEA Rod Swap Redesign.

5.1.8 Inlet Temperature Coastdown The Plant Parameters Document allows for an inlet temperature between 548ºF and 537ºF at HFP to allow for a plant coastdown at EOC conditions. Framatome Inc. has produced analyses to support this coastdown operation for Units 1 and 2. 7KHVH DQDO\VHV UHPDLQ DSSOLFDEOH

therefore, no events require reanalysis at coastdown conditions.

5.2 Chapter 14 Event Review The CCNPP UFSAR Chapter 14 safety analysis events were reviewed with respect to the changes listed in Section 5.1, with the objective of determining whether:

[

]

The summary of the review and the reanalysis conducted as needed are presented in this section, and also summarized in Table 5-5. The events are described in the order as presented in the NRC Standard Review Plan, with reference to the appropriate CCNPP UFSAR section. Not all events listed in the NRC Standard Review Plan are applicable to CCNPP, and this is noted on an event-by-event basis.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-8 The use of PORVs is noted as a pressure relieving device assumed to limit the primary system pressure in a number of analyses. The CE design includes a High Pressurizer Pressure reactor trip interlock in the opening logic for the PORVs. Therefore, this trip signal has to be present for the PORVs to actuate. [

] in the analyses performed to generate boundary conditions for the DNB analysis to

[

]

An evaluation of the effect of the LTA on the Chapter 14 Non-LOCA events confirmed that [

] are potentially impacted by the LTAs. Of those events impacted by the LTAs, the events that are [

] Events which are [

] With the plant operating restrictions described in Section 4.4, the [

] concluded that all of the Chapter 14 Non-LOCA analyses of record bound operation with the LTA.

The thermal-hydraulic design evaluations were performed with the existing methods applicable to Calvert Cliffs Units 1 and 2. The evaluations verified that the LTAs are [

] with respect to thermal-hydraulic margin and that the LTAs are hydraulically compatible with the resident fuel assemblies. The evaluations [

] An assessment of the evaluations validates that the LTA thermal-hydraulic reload design remains bounded and justifies the [

] to the LTAs.

A technical evaluation to assess the potential impacts of the LTA with PROtectTM Accident Tolerant Fuel design to the Calvert Cliffs LOCA licensing bases was performed in Cycle 24 and DERXQGLQJ3&7HVWLPDWHIRUWKHSRWHQWLDOLPSDFWVZDVGHWHUPLQHG7KHHYDOXDWLRQUHVXOWHGLQ

/2&$3&7SHQDOWLHVIRUERWK5/%/2&$DQG6%/2&$7KHVH3&7 penalties will continue to be For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-9 applicable for Cycle 26 to cover the LTA throughout its planned operating cycles (Section 5.2.6.5.4).

5.2.1 Increase in Heat Removal by the Secondary System (SRP 15.1) 5.2.1.1 Decrease in Feedwater Temperature (SRP 15.1.1, UFSAR 14.7) 5.2.1.1.1 Event Description A Decrease in Feedwater Temperature event is assumed to be initiated by the loss of feedwater heating. This may occur due to the loss of steam flow extracted from the turbine or due to an accidental opening of a feedwater heater bypass line. The UFSAR defines the most limiting Excess Feedwater Heat Removal Event as occurring at HFP, with the loss of both high-pressure feedwater heaters. The event results in a decrease of the secondary side enthalpy leading to an increase in the primary-to-secondary side heat transfer. The steam generator outlet temperature on the primary side decreases, causing the core inlet temperature to also decrease.

The system response to this event is that the RCS temperature and pressure will decrease. When there is a negative Moderator Temperature Coefficient, a positive reactivity feedback occurs in the core in response to the decreasing core average temperature. This increases core power and the core average heat flux. Elevated cladding heat fluxes and fuel temperatures in the hot assembly may challenge the MDNBR and the Linear Heat Rate Limits, which are the Specified Acceptable Fuel Design Limits.

9+3DQG70/3WULSVDUHQRWFUHGLWHGIRUWKLVHYHQWWKHUHIRUHDQHZHTXLOLEULXPsteady state is reached until operators manually trip the plant.

5.2.1.1.2 Event Disposition and Justification The AOR for the system response to this event was performed at HFP with the fuel at EOC conditions. The reactor coolant system response is determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The analysis was performed with a most negative MTC of -33 pcm/ºF, which resulted in a quasi-equilibrium operation at a new steady-state power of

~116% RTP. No credit was taken for any reactor trip, including VHP and TM/LP trips. A separate DNBR analysis was not implemented for this event because the transient core thermal-hydraulic parameters for the event are bounded by the Increase in Steam Flow (Excess Load) event, which was reanalyzed to support the fuel transition, and described in this report in Section 5.2.1.3.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-10 The AOR bounds the core design, so no re-analysis of this event was required.

5.2.1.2 Increase in Feedwater Flow (SRP 15.1.2, UFSAR 14.7, 14.12) 5.2.1.2.1 Event Description The Increase in Feedwater Flow event is initiated by a failure in the feedwater system. This is also defined in the UFSAR as one of the Asymmetric SG events, causing excess feedwater to one SG.

This event results in an increase in the primary-to-secondary side heat transfer due to increased feedwater flow. The steam generator outlet temperature on the primary side decreases causing the core inlet temperature to also decrease. In the presence of a negative MTC, a reduced core inlet temperature results in an increase in the core power and a decrease in thermal margin.

5.2.1.2.2 Event Disposition and Justification The UFSAR states that this event is bounded by the Decrease in Feedwater Temperature event described in Section 5.2.1.1, which in turn is bounded by the Increase in Steam Flow (Excess Load) event described in Section 5.2.1.3. The changes being incorporated in this cycle will not alter this conclusion since the controlling factor is the cooldown rate. Therefore, this event is not re-analyzed for the core design.

5.2.1.3 Increase in Steam Flow (SRP 15.1.3, UFSAR 14.4) 5.2.1.3.1 Event Description This event is defined as any rapid, uncontrolled increase in SG steam flow caused by something other than a Steam Line Break. It is initiated by a failure or mis-operation of the main steam system that results in an increase in steam flow from the steam generators. Full opening of the turbine control valves, atmospheric dump valves or turbine bypass valves during power operation would result in an Increase in Steam Flow (Excess Load) event. The increased steam flow creates a mismatch between the heat being generated in the core and that being extracted by the steam generators. As a result of this power mismatch, the primary-to-secondary heat transfer increases and the primary system cools down. If the MTC is negative, cooldown of the primary system coolant would cause an insertion of positive reactivity and the potential erosion of thermal margin.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-11 5.2.1.3.2 Event Disposition and Justification The controlling parameters for the system response to this event are the magnitude of the cooldown rate and the value of the MTC. The cooldown rate is determined by the nature of the initiating event - whether the initiating failure is the turbine control valve, atmospheric dump valve or turbine bypass valve, which determines the increase in steam flow rate. This depends on whether the plant is initially at HFP or HZP conditions. Hence both HFP and HZP conditions were analyzed, with the fuel at EOC conditions. The HFP analysis considered a spectrum of MTC values, including the most negative MTC value specified in the Technical Specifications. The HZP analysis used [

] biased to support the Technical Specification HFP most-negative MTC limit value. [

]

Additional cases assuming [

] were also analyzed. A

[

] to ensure conservatism.

The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4).

The HFP analysis assumed an [

] increase in steam flow that bounds the capacity of the Atmospheric Dump Valve and Turbine Bypass systems. The HZP analysis assumes an [

] full opening of all turbine control valves. All cases analyzed assumed initial conditions and uncertainties [

] The results showed that the DNBR and FCM SAFDLs are not violated.

The potential for return-to-power following scram was also evaluated. The reactor returned to power following scram when a MSIV is assumed to fail to close for a minimum shutdown margin of 3500 pcm. Boration from HPSI returns the core to a subcritical condition. The peak return-to-power was comparable to and bounded by those for comparable limiting Main Steam Line Break events, described in Section 5.2.1.5.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-12 The DNB performance for this event is verified in the TM/LP setpoint analysis for cases tripping RQ 70/3 FDVHV WULSSLQJ RQ 9+37 DUH ERXQGHG E\ WKH &($ :LWKGUDZDO DW 3RZHU

(Section 5.2.4.2).

The FCM performance for this event is verified in the LPD LSSS setpoint analysis.

The transient response AOR was previously re-analyzed with [

]

5.2.1.4 Inadvertent Opening of a Steam Generator Relief or Safety Valve (SRP 15.1.4, UFSAR 14.12) 5.2.1.4.1 Event Description This event is initiated by an increase in steam flow caused by the inadvertent opening of a steam generator relief or safety valve. This is defined in the UFSAR as an Asymmetric SG event. An asymmetric SG event can be caused by excess feedwater, loss of feedwater, excess load or loss of load to only one SG. The increase in steam flow rate causes a mismatch between the heat generation rate on the primary side and the heat removal rate on the secondary side. As a result of this power mismatch, the primary-to-secondary heat transfer increases and the primary system cools down. If the MTC is negative, cooldown of the primary system coolant would cause an insertion of positive reactivity and the potential erosion of thermal margin.

5.2.1.4.2 Event Disposition and Justification The increase in steam flow due to the inadvertent opening of a steam generator valve is less than that considered in the Increase in Steam Flow event described in Section 5.2.1.3. Therefore, the consequences of this event are bounded by the Increase in Steam Flow (Excess Load) event described in Section 5.2.1.3. The changes being addressed for the CEA Rod Swap Redesign will not alter this conclusion since the controlling factor for this event is the cooldown rate.

From the perspective of asymmetry, the Loss of Load to one SG, described in Section 5.2.2.4.3, will produce a larger temperature difference (asymmetry) between the two primary coolant loops.

The AOR bounds the core design, so no re-analysis of this event was required.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-13 5.2.1.5 Steam System Piping Failures Inside and Outside of Containment (SRP 15.1.5, UFSAR 14.14) 5.2.1.5.1 Event Description A steam line piping failure event, or MSLB, is initiated by a rupture of a main steam line pipe upstream of the MSIVs causing an uncontrolled steam release from the secondary system. As a result of the uncontrolled release of steam, the heat extraction rate from the primary side exceeds the core heat generation rate and reduces the primary side temperatures. The primary side cooldown, coupled with a negative MTC, results in reactivity addition and increases reactor power.

This, in conjunction with potential decalibration and harsh environment conditions can reduce thermal margin before reactor scram and potentially erode shutdown margin after scram. The erosion of shutdown margin after scram may result in a return-to-power which, in turn, challenges thermal margin. The consequences of this event are governed by the steam flow rate out of the ruptured steam line, the primary pump operating assumptions (i.e., with or without offsite power),

the magnitude of the MTC, the initial primary side operating state, decalibration effects, and increase in RPS trip setpoint uncertainties caused by harsh environment conditions. The pre-scram and post-scram aspects of this event are considered.

5.2.1.5.2 Event Disposition and Justification Two separate analyses were performed for the MSLB event, pre-scram and post-scram. The pre-scram analysis represents the highest reactor power condition and employs assumptions that minimize DNBR and maximize LHGR during this time frame. The post-scram analysis was performed to determine the MDNBR and the peak LHGR during the return to power caused by the overcooling.

It is noted that CCNPP does not have non-return check valves in the steam lines. Hence, an MSLB will cause both SGs to supply the break flow until MSIV closure. A large number of cases were analyzed to cover possible break locations and initial conditions. The significant factors to consider are:

This is a cooldown event where downcomer fluid temperature is changing and therefore affects the NI power measurement calibration. The nuclear power level indicated by the ex-core detectors is lower than the actual power level when the coolant entering the For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-14 reactor vessel is colder than the normal full-power coolant temperature. Maximum cooldown rates will result in maximum decalibration.

Breaks inside containment result in harsh containment conditions, increasing the uncertainty of the RPS trip setpoints.

Breaks outside containment will not cause an RPS trip signal due to containment high pressure, which is a common feature for breaks inside containment. This affects the timing of key events.

5.2.1.5.2.1 Pre-Scram MSLB Analysis The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). All analyses were initiated from HFP conditions and assumed loss of offsite power coincident with reactor trip. The loss of offsite power automatically causes RCP trip and coastdown. Cases analyzed include breaks inside containment, breaks outside containment upstream of the MSIV, and breaks outside containment downstream of the MSIV. A spectrum of break sizes was analyzed ranging from

[

] to the maximum pipe area in the region of the break. Typical of analyses for cooldown events, a spectrum of MTC values was analyzed, up to a value that bounds the most negative value allowed by the Technical Specifications. All other initial conditions were assumed at values biased to challenge the SAFDLs.

The transient response AOR was previously re-analyzed with [

]

The MDNBR for this event is greater than the correlation limit.

The peak LHGR during the event was shown to remain below the limit that precludes FCM.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-15 5.2.1.5.2.2 Post-Scram MSLB Analysis The post-scram MSLB analysis is focused on return-to-criticality. The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis. The reactor was tripped at the beginning of the transient.

The break location was chosen to be upstream of the MSIV close to the SG exit at the flow restrictor. A double-ended break was assumed at this ORFDWLRQ however, the SG side break flow rate is limited by the area of the flow restrictor at the SG exit. Together with this, the analysis assumed that the MTC is at a value that bounds the most negative allowed value. This set of assumptions provides the maximum cooldown rate and the most positive reactivity feedback. With this set of assumed conditions, loss of offsite power and initial power (HFP vs. HZP) were investigated as sensitivity studies. In addition, [

] The limiting single failure assumed is the failure of one of the two HPSI pumps to start because the event is eventually mitigated by negative reactivity inserted due to boron, which is delivered by the HPSI pumps.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

The MDNBR for this event is greater than the correlation limit.

The peak LHGR during the event was shown to remain below the limit that precludes FCM.

The conservatism of the S-RELAP5 model with respect to reactivity has been confirmed to be conservative.

5.2.1.5.2.3 Radiological Dose Calculations for Steam Line Break Dose evaluations are Constellation scope and therefore outside the scope of this document.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-16 5.2.2 Decrease in Heat Removal by the Secondary System (SRP 15.2) 5.2.2.1 Loss of External Load (SRP 15.2.1, UFSAR 14.5) 5.2.2.1.1 Event Description A Loss of Load event is defined in the UFSAR as any event that results in the reduction of the SGs heat removal capacity through the loss of secondary steam flow. Closure of all MSIVs, turbine stop valves, or turbine control valves will cause a Loss of Load event. Of these, the turbine stop valves have the quickest closure time.

Typically, this event challenges the RCS primary and secondary upper pressure limit of 110% of design. The event is mitigated by the high pressure trip, TM/LP trip or the Variable High Power trip.

5.2.2.1.2 Event Disposition and Justification The key parameters affecting the progress of this event are plant related system parameters -

initial reactor power, RPS trip setpoints, uncertainties and delays, PSV setpoint and capacity, MSSV setpoints and capacities, number of MSSVs allowed to be inoperable. The only fuel related parameter that could affect this event is the MTC, with a positive value being bounding because of a possible increase in power associated with an increase in RCS fluid temperature. The most positive MTC value with Framatome Inc. HTP' fuel is less than the value used in the analysis of record.

The AOR bounds the core design, so no re-analysis of this event was required.

5.2.2.2 Turbine Trip (SRP 15.2.2, UFSAR 14.5) 5.2.2.2.1 Event Description This event is initiated by a turbine trip which results in the rapid closure of the turbine stop valves.

A reactor trip would occur on a turbine trip and the steam dump system would operate to mitigate the consequences of this event. The primary system is protected against overpressurization by the pressurizer safety and relief valves. Pressure relief on the secondary side is afforded by the steam line safety/relief valves.

5.2.2.2.2 Event Disposition and Justification The key parameters affecting the progress of this event are plant related system parameters - initial reactor power, RPS trip setpoints, uncertainties and delays, PSV setpoint and capacity, MSSV For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-17 setpoints and capacities, number of MSSVs allowed to be inoperable. It is bounded by the Loss of External Electrical Load event discussed in Section 5.2.2.1.

5.2.2.3 Loss of Condenser Vacuum (SRP 15.2.3)

This event will result in loss of steam flow and consequently a turbine trip with attendant closure of the turbine stop valves. It is bounded by the Loss of External Electrical Load event discussed in Section 5.2.2.1.

5.2.2.4 Closure of Main Steam Isolation Valves (SRP 15.2.4) 5.2.2.4.1 Event Description This event is caused by the closure of one or both MSIVs due to an electrical malfunction, valve controller failure, valve failure, or operator error. The closure of these valves drastically reduces the steam load. The main steam safety/relief system will operate to relieve secondary pressure. The loss of steam flow and the associated heat-up of the primary system will cause increase in RCS pressure. With a positive MTC value, reactor power can increase in the short term. The event is mitigated by the RPS High Pressure trip, TM/LP trip or Variable High Power trip.

5.2.2.4.2 Dual MSIV Closure (UFSAR 14.5)

For simultaneous closure of both MSIVs, the event will progress very similarly to the Loss of External Load Event or the Turbine Trip event. As stated in the UFSAR Section 14.5.1, the Turbine Stop Valve closure time is smaller than the MSIV closure time. Thus, the consequences of this event are bounded by the Loss of External Electrical Load event discussed in Section 5.2.2.1.

The introduction of Framatome Inc. HTP' fuel and other recent plant changes (see Section 5.1) do not change this conclusion.

5.2.2.4.3 Single MSIV Closure (UFSAR 14.12)

The single MSIV closure results in asymmetric conditions and is analyzed in the UFSAR under the classification of Asymmetric SG events. The closure of the MSIV causes the pressure and temperature of the SG to increase. The core inlet temperature from the isolated SG increases due to the loss of steam flow and the transfer of heat to the secondary side through the SG. The isolated SG sees a rapid decrease in level because the rise in pressure collapses the steam bubble. The SG pressure continues to increase until the MSSVs open. The increased load demand in the other For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-18 SG causes a pressure decrease and increase in heat transfer, causing a decrease in the loop temperatures on the side of the unaffected SG.

The event is terminated by the reactor trip signal from the ASGPT. Other reactor trip signals that may be invoked are the signals based on Low SG Pressure, Low SG Level, TM/LP, or VHPT.

This event was reanalyzed with Framatome Inc. HTP' fuel because it is the limiting asymmetric SG event, and also as a demonstration of the ASGPT signal setpoint.

The analysis was initiated from HFP conditions with an MTC value which bounds the most negative MTC value allowed by the Technical Specifications. The analysis assumed that the turbine valve opens to satisfy the increased load demand caused by the loss of one SG.

The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). The ASGPT trip signal will occur fairly quickly, before there is time to develop any significant asymmetry in temperature that would cause a significant core power tilt. The evaluation was performed using a [

] A sensitivity study was also conducted [

] The limiting case has [

] 0% steam generator tube plugging and an MSIV closure time of [

] These assumptions produce the maximum delay in the ASGPT signal and the maximum core heat flux.

The analysis demonstrated that the event is terminated by the ASGPT signal which occurs very quickly (less than [

] ).

The MDNBR performance for this case is bounded by the Pre-Scram Steam Line Break (Section 5.2.1.5).

The FCM performance for this case is bounded by the Pre-Scram Steam Line Break (Section 5.2.1.5).

The transient response AOR bounds the core design, so no re-analysis of this event was required.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-19 5.2.2.5 Steam Pressure Regulator Failure (SRP 15.2.5)

This event will result in loss of steam flow and consequently a turbine trip with attendant closure of the turbine stop valves. It is bounded by the Loss of External Electrical Load event discussed in Section 5.2.2.1.

5.2.2.6 Loss of Non-Emergency AC Power (SRP 15.2.6, UFSAR 14.10)

This event causes a trip of the RCPs and the main feedwater pumps. The short term response is identical to the Loss of Reactor Coolant Flow event, with the assumption of loss of MFW flow, which was reanalyzed for implementation of Framatome Inc. HTP' fuel and discussed in Section 5.2.3.1.

The challenges to the SAFDL limits are bounded by the Loss of Reactor Coolant Flow analysis discussed in Section 5.2.3.1. The longer-term system responses to this event are not impacted by the transition to Framatome Inc. HTP' fuel because the key parameters for this event are plant system related. Hence it was not specifically analyzed for the fuel transition.

Constellation is expected to ensure that the identified plant changes do not impact the Westinghouse Analysis of Record.

5.2.2.7 Loss of Normal Feedwater Flow (SRP 15.2.7, UFSAR 14.6) 5.2.2.7.1 Event Description A Loss of Normal Feedwater Flow transient is initiated by the trip of the main feedwater pumps or a malfunction in the feedwater control valves. The loss of main feedwater flow decreases the amount of subcooling in the secondary side downcomer which diminishes the primary-to-secondary system heat transfer and leads to an increase in the primary system coolant temperature. As the primary system temperatures increase, the coolant expands into the pressurizer which increases the pressure by compressing the steam volume. The increase in primary pressure may cause the pressurizer PORVs to open.

Steam generator liquid levels, which have been steadily dropping since the termination of MFW flow, soon reach the low steam generator level reactor trip setpoint. This initiates a reactor scram, which ends the short-term-heat-up phase of the event.

The automatic turbine trip at reactor scram and the continuing primary-to-secondary transfer of the decaying core power and the reactor coolant pump heat cause steam generator pressures to rapidly increase. When steam generator pressures and coolant temperatures have increased to the For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-20 appropriate values, the steam dump system and/or the MSSVs serve to limit the increase in steam generator pressures. However, credit is typically not taken in the event analysis for the steam dump system since it is not safety grade.

Steam generator levels continue to drop and soon reach the low-low steam generator level AFW actuation setpoint. This initiates the starting sequence for the AFW pumps. When the delivery of AFW begins, the rate of level decrease in the fed steam generators slows.

Eventually, a long-term-heat-up phase of the event may begin if primary-to-secondary heat transfer degrades as a result of steam generator tube uncovery. If AFW is not being delivered to one of the steam generators, that steam generator may completely dry out.

As the decay heat level drops, liquid levels in the fed steam generators stabilize and then begin to rise. Also, reactor coolant temperatures stabilize and then begin to decrease. These conditions mark the end of the challenge to the event acceptance criteria. The long-term cooling of the primary system is governed by the heat removal capacity of the AFW flow.

5.2.2.7.2 Event Disposition and Justification The key parameters for this event are plant system related and not impacted by the transition to Framatome Inc. HTP' fuel. The [

] is the assumed positive value of the MTC, which causes core power increase as the core fluid temperature increases. The analysis of record assumes the most positive MTC value allowed by the Technical Specifications and bounds the most positive value associated with Framatome Inc. HTP' fuel.

The AOR bounds the core design, so no re-analysis of this event was required.

5.2.2.8 Feedwater System Pipe Breaks Inside and Outside Containment (SRP 15.2.8, UFSAR 14.26) 5.2.2.8.1 Event Description The Feedwater Line Break event is defined as a major break in a main feedwater line that is sufficiently large to prevent maintaining the SG secondary side water inventory in the affected SG.

This event can be considered as a heat-up event, a cool-down event, or a combination of both. The decrease in FW flow causes lower SG inventory and reduced heat removal resulting in RCS heat-up and pressurization. This initial heat-up transient is terminated by a reactor trip on either High For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-21 Pressurizer Pressure or Low SG Level. During this initial period, the RCS pressure can show a first peak. The RCS heat-up can continue even after reactor trip due to total loss of heat transfer in the affected SG as the liquid inventory is completely depleted. The RCS pressure then increases. The opening of the PSVs and the MSSVs serve to mitigate RCS overpressurization. The second peak in RCS pressure could be higher than the previous peak value.

Following the reactor trip, the RCS begins to cool down as a result of the heat removal from the affected SG. The RCS pressure may decrease enough to cause HPSI to activate. The cool-down portion of the transient is terminated by dry-out of the affected SG, which dramatically reduces the heat removal from the RCS.

The lack of main feedwater results in a long-term heat-up similar to the Loss of Feedwater event.

AFW flow is actuated on the AFAS. The expansion of the reactor coolant and the potential HPSI flow will re-pressurize the RCS and cause pressurizer level to increase back to normal levels. AFW will eventually restore the inventory in the unaffected SG and the decay heat will be removed via steam flow through the MSSVs. As the decay heat levels drop, the liquid level in the unaffected SG stabilizes and then begins to rise. Also, RCS temperatures stabilize and then begin to decrease.

When the unaffected SG levels begin to increase and the RCS temperatures begin to decrease, the FWLB transient is considered terminated.

5.2.2.8.2 Event Disposition and Justification The UFSAR presents an analysis of this heat-up transient to demonstrate that the primary and secondary pressure limits are not exceeded and that the radiological release is within acceptable limits. The RCS heat-up does not cause fuel design limits to be exceeded. This event is the limiting overpressure event in the UFSAR analysis. Excessive heat removal through the feedwater line break is not considered because the cooldown potential is less than that for the MSLB event (Section 5.2.1.5).

The key parameters for this event are plant system related and not impacted by the transition to Framatome Inc. HTP' fuel. The [

] is the assumed positive value of the MTC, which causes core power increase as the core fluid temperature increases. The analysis of record assumes the most positive MTC value allowed by the Technical Specifications and bounds the most positive value associated with Framatome Inc. HTP' fuel.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-22 The AOR bounds the core design, so no re-analysis of this event was required.

5.2.3 Decrease in Reactor Coolant System Flow (SRP 15.3) 5.2.3.1 Loss of Forced Reactor Coolant Flow (SRP 15.3.1, UFSAR 14.9) 5.2.3.1.1 Event Description The Loss of Forced Reactor Coolant Flow transient is initiated by a disruption of the electrical power supplied to or a mechanical failure in an RCS pump. These failures may result in a complete or partial loss of forced coolant flow. A complete loss of reactor coolant flow is more severe and is the event analyzed in the UFSAR.

The impact of losing one or more RCPs is a decrease in the active flow rate in the reactor core and an increase in core temperatures. The increase in core fluid temperature along with a positive MTC value causes an increase in core power. The core heat flux lags the core power due to the fuel thermal inertia. A reactor trip signal on Low RCS Flow causes insertion of control rods and the increase in core power is terminated. The core flow continues to decrease while the core heat flux is still high (lagging the core power). Hence the DNBR continues to decrease. When the control rods are sufficiently inserted and the core heat flux starts to decrease, the DNBR reaches a minimum value, and the DNBR transient is terminated.

At the same time, because the MFW flow is tripped, the steam generator primary-to-secondary heat transfer rate decreases. The MFW trip is assumed in the Framatome Inc. analysis (see Section 5.2.3.1.2 below). The decreasing rate of heat removal in the steam generators and the decreasing flow of primary coolant cause the reactor coolant to heat up. The resultant reactor coolant expansion causes fluid to surge into the pressurizer and overpressurization of the RCS.

This may actuate the automatic pressurizer spray system and may open the pressurizer PORVs.

5.2.3.1.2 Event Disposition and Justification The primary safety concern with this event is the reduction of DNBR margin and a challenge to the DNBR SAFDL. The FCM SAFDL is not challenged because the reactor power does not increase significantly in this event. Some of the key parameters for this event, such as minimum scram worth and fuel rod gap conductance (affecting the fuel rod thermal response time constant), are potentially impacted by the transition to Framatome Inc. HTP' fuel. This event was also analyzed to verify the RPS low RCS flow trip. Hence this event was reanalyzed with Framatome Inc. HTP' fuel.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-23 The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). The analysis was initiated by tripping all four RCPs with the plant at HFP condition. MFW pumps were assumed tripped at transient initiation. This allows the MDNBR evaluation for the Loss of Non-Emergency AC Power event (Section 5.2.2.6) to be bounded by this event. The analysis was conducted at HFP BOC conditions, with a maximum positive Technical Specification MTC value, maximum initial core inlet temperature, minimum initial reactor coolant flow rate, and a conservative pump flow coastdown curve. These assumptions provide the maximum challenge to the MDNBR limit. The RPS provides the mitigation for this event, and it has sufficient redundancy. Hence, there are no active single failures that could result in more adverse consequences.

The analysis showed that the plant system transient response is as expected. Pressurizer spray was shown to activate in the analysis, and the PORVs opened to relieve primary pressure.

However, pressurizer level was within normal bounds and there is no liquid carryover into the PORVs.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

The MDNBR for this event is analyzed statistically on a cycle-by-cycle basis as a part of the DNB LCO barn setpoint verification to evaluate the effect of cycle specific kinetics parameters (See Section 6.0).

5.2.3.2 Flow Controller Malfunction (SRP 15.3.2)

There are no flow control devices in the reactor coolant system of the CCNPP Units. Therefore, this event is not credible.

5.2.3.3 Reactor Coolant Pump Rotor Seizure (SRP 15.3.3, UFSAR 14.16) 5.2.3.3.1 Event Description This event is initiated by an instantaneous seizure of an RCP rotor. The seizure causes an immediate reduction in RCS flow rate. As in the Loss of Forced Coolant Flow event (Section 5.2.3.1), the impact of losing an RCS pump is a decrease in the active flow rate in the reactor core and an increase in core temperatures. The increase in core fluid temperature along with a positive MTC value causes an increase in core power. The core heat flux lags the core power For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-24 due to the fuel thermal inertia. A reactor trip signal on Low RCS Flow causes insertion of control rods and the increase in core power is terminated. The core flow continues to decrease while the core heat flux is still high (lagging the core power). Hence the DNBR continues to decrease. When the control rods are sufficiently inserted and the core heat flux starts to decrease, the DNBR reaches a minimum value, and the DNBR transient is terminated.

At the same time, the steam generator primary-to-secondary heat transfer rate decreases, because (1) the decreasing primary coolant flow degrades the steam generator tube primary-side heat transfer coefficients and (2) the turbine trip causes the secondary-side temperature to increase. The decreasing rate of heat removal in the steam generators and the decreasing flow of primary coolant cause the reactor coolant to heat up. The resultant reactor coolant expansion causes fluid to surge into the pressurizer and overpressurization of the RCS. This may actuate the automatic pressurizer spray system and may open the pressurizer PORVs.

5.2.3.3.2 Event Disposition and Justification The most limiting scenario for a Reactor Coolant Pump Seizure event is defined in the UFSAR as an instantaneous seizure of a single RCP shaft. The RCS flow is asymmetrically reduced to three-pump flow. The primary safety concern with this event is the reduction of DNBR margin and a challenge to the DNBR SAFDL. The FCM SAFDL is not challenged because the reactor power does not increase significantly in this event. Some of the key parameters for this event, such as minimum scram worth and fuel rod gap conductance (affecting the fuel rod thermal response time constant), are potentially impacted by the transition to Framatome Inc. HTP' fuel. This event was also analyzed to verify the RPS low RCS flow trip. Hence this event was analyzed with Framatome Inc. HTP' fuel.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-25 The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). The analysis was initiated by instantaneously stopping one RCP with the plant at HFP condition. Typically, loss of offsite power is assumed coincident with reactor trip. Note that the plant licensing basis does not assume loss of offsite power for this event. Hence offsite power was assumed to be available. The analysis was conducted at HFP BOC conditions, with a maximum positive Technical Specification MTC value, maximum initial core inlet temperature, and minimum initial reactor coolant flow rate. These assumptions provide the maximum challenge to the MDNBR limit. The RPS provides the mitigation for this event, and it has sufficient redundancy. Hence, there are no active single failures that could result in more adverse consequences. Since two of the cold legs supply water to the pressurizer spray, [

]

The analysis showed that the RCS flow quickly drops to 75% of the initial flow as a result of the seized rotor. The calculated plant system transient response is as expected. The reactor trip signal was received very quickly (0.205 s) followed by turbine trip (0.704 s). The analysis case with the seized rotor in Loop 1A (loop with pressurizer) showed a slightly lower peak RCS pressure and is therefore considered more limiting with respect to DNBR limits. Pressurizer spray was shown to activate in the analysis, and the PORVs opened to relieve primary pressure.

However, pressurizer level is within normal bounds and there is no liquid carryover into the PORVs. [

]

The transient response AOR bounds the core design, so no re-analysis of this event was required.

MDNBR for this event was evaluated using reduced inlet flow factors due to an asymmetric core inlet flow distribution. The MDNBR for this event is greater than the correlation limit.

5.2.3.4 Reactor Coolant Pump Shaft Break (SRP 15.3.4)

The RCP Shaft Break event is often analyzed in combination with the RCP Seized Rotor event (SRP 15.3.3) as a separate but similar event. However, breaking or shearing an RCP shaft is not part of the licensing basis of the plant. Hence this event is not analyzed.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-26 5.2.4 Reactivity and Power Distribution Anomalies (SRP 15.4) 5.2.4.1 Uncontrolled Control Rod Assembly Withdrawal from a Subcritical or Low Power Startup Condition (SRP 15.4.1, UFSAR 14.2) 5.2.4.1.1 Event Description The uncontrolled withdrawal of a CEA bank could be caused by a malfunction in the reactor control or rod control systems or by operator error. The malfunction could lead to a large and rapid positive reactivity addition, resulting in a power transient which challenges the DNBR and FCM SAFDLs.

For events with high reactivity addition rates, the positive reactivity insertion from the withdrawn control bank causes a significant core power increase, and the core average and hot leg temperatures also increase. The positive reactivity insertion is countered by the negative reactivity feedback provided by the Fuel (Doppler) Temperature Coefficient (FTC). This inherent self-limitation of the power excursion limits the core power to a tolerable level during the delay time for protective action.

Because of the delays in the protection system and the time needed for control rod insertion to become effective, the nuclear power can peak at a very high level during the rapid excursion, but the duration is short enough to preclude significant energy deposition. The fuel rod surface heat flux lags behind the nuclear power level but still peaks at a significant fraction of the rated-power value.

The increase in the primary coolant temperatures, in turn, lags behind the increase in the fuel rod heat flux due to the loop cycle time. Hence the MTC does not have a large impact, but a positive MTC value will contribute to the rate of power increase during the power excursion.

For events with lower reactivity addition rates, the increase in the neutron flux is slower and does QRWRYHUVKRRWWKH9DULDEOH+LJK3RZHUWULSVHWSRLQWKRZHYHU, the slower neutron increase permits the core heat flux to rise higher, and thereby challenge the transient acceptance criteria.

The RPS is designed to terminate the transient before the DNBR limit is reached. The principal protective trip for this event is the Variable High Power Trip. Additional protection is provided by the TM/LP and the LPD Trip signals. The High Rate-of-Change of Power Trip will also be actuated, but the safety evaluations credit this trip only for transients initiated from a subcritical condition, to exclude these events from the analysis.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-27 During the event, as the RCS fluid temperature increases, the RCS pressure increases correspondingly. Depending on the reactivity insertion rate, the RCS pressure could increase to the PORV setpoint. The pressurizer pressure and level control systems will act to mitigate the RCS pressure increase, but the level control system is not simulated in safety analysis. On the secondary side, after reactor trip followed by turbine trip, the steam dump and bypass system will act to modulate the SG pressure at 900 psia and the RCS average temperature at 532oF.

However, this system is not credited in the safety analysis, and the secondary pressure may increase to the MSSV setpoint.

5.2.4.1.2 Event Disposition and Justification The key parameters in the analysis of this event are the reactivity insertion rate due to rod motion, the FTC, the MTC, and the maximum predicted FQ. The rod worth, FTC, and maximum predicted FQ can be affected by the introduction of Framatome Inc. HTP' fuel. Hence this event was analyzed with Framatome Inc. HTP' fuel.

The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). For the maximum reactivity addition rate case, the analysis used a single bounding case for Mode 2 (Startup) and Mode 3 (Hot Standby) using a combination of the lowest initial power level and highest reactivity addition rate.

For low reactivity addition rates, a spectrum of cases was analyzed at HZP. At these conditions, the transient proceeds slower, and permits the core heat flux to approach a thermal power level consistent with the decalibrated VHPT setpoint of 53.7% RTP. The initial power was assumed at 10-9 RTP, corresponding to the lowest possible value following an extended shutdown. The extremely low initial neutron population at this condition delays the power increase when the CEAs are withdrawn until a significant amount of reactivity has been added - maximizing the subsequent power excursion.

The minimum number of RCPs in operation allowed by the Technical Specifications for Mode 3 is two (one RCS loop). However, a CEA withdrawal event initiated from Mode 3 would be protected by the Low RCS Flow Trip. In Mode 3, this trip signal is available when the power is above 10-4

%RTP. During the transient power excursion starting at 10-9 RTP, this trip would be activated and terminate the event well before the SAFDLs are challenged. Hence the analysis assumed that 4 RCPs are running at event initiation.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-28 The least negative value for FTC and the most positive value for MTC were used to maximize the power increase due to rod withdrawal. This corresponds to BOC fuel conditions. The maximum analyzed reactivity insertion rate is 16 pcm/s, assuming a maximum withdrawal rate of 30 inches/min and a differential worth of 32 pcm/inch chosen to bound cycle-to-cycle variations.

For the high reactivity addition rate case, the results showed that the VHP-NI trip signal (30% RTP

XQFHUWDLQW\ ZDVUHFHLYHGDWVHFRQGVWKHPD[LPXPQXFOHDUSRZHURI573ZDV

reached at 38.55 seconds, and the maximum surface heat flux was reached at 40.16 seconds.

Pressurizer spray actuated at [

] seconds and the PORVs opened at [

] seconds.

An excore NI decalibration factor of 0.677 was assumed, which bounds rod shadowing and calibration uncertainties. The analysis showed that the fuel SAFDLs are not violated.

To reduce the challenge to cladding strain acceptance criteria for this event following the CEA swap described in Section 5.1.1.1, plant operating restrictions limiting low power operation were implemented as described in Section 4.4 to exclude initial conditions which may lead to a fast transient, which are more challenging for this event. For initial power levels greater than 1% RTP, the transient response does not challenge cladding acceptance criteria.

With plant operating restrictions preventing power operation at or below 1% RTP, the transient response AOR bounds the core design, so no re-analysis of this event was required.

The MDNBR performance for this event is bounded by the Uncontrolled Control Rod Bank Withdrawal at Power (Section 5.2.4.2).

The FCM performance for this event is bounded by the Uncontrolled Control Rod Bank Withdrawal at Power (Section 5.2.4.2).

5.2.4.2 Uncontrolled Control Rod Bank Withdrawal at Power (SRP 15.4.2, UFSAR 14.2) 5.2.4.2.1 Event Description As with the Uncontrolled Control Rod Assembly Withdrawal From a Subcritical or Low Power Startup Condition (Section 5.2.4.1), this event is initiated by an uncontrolled withdrawal of a control rod bank. This withdrawal adds positive reactivity to the core, which leads to potential power and temperature excursions. Event 15.4.2 considers the consequences of control bank withdrawals at rated and intermediate initial power levels.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-29 As the control bank is withdrawn, the positive reactivity insertion causes a significant core power increase, and the core average and hot leg temperatures also increase. The positive reactivity insertion is countered by the negative reactivity feedback provided by the FTC. This inherent self-limitation of the power excursion limits the core power to a tolerable level during the delay time for protective action.

The transient response for the event at HFP is slower than at HZP. The increase in neutron flux resulting from the HFP CEA bank withdrawal is followed by a rise in thermal power. The thermal power, or the fuel rod surface heat flux, lags behind the nuclear power level. The increase in the primary coolant temperatures, in turn, lags behind the increase in the fuel rod heat flux due to the loop cycle time. At HFP, since the event is slower than at HZP, the MTC has more of an effect, and a positive MTC value will contribute to the rate of power increase during the power excursion. The increasing core heat flux and primary coolant temperature decrease margin to the fuel SAFDLs.

The RPS is designed to terminate the transient before the DNBR limit is reached. The principal protective trips for this event are the VHPT and the TM/LP trip.

5.2.4.2.2 Event Disposition and Justification The key parameters in the analysis of this event are the reactivity insertion rate due to rod motion, the FTC and the MTC. The rod worth and the FTC can be affected by the introduction of Framatome Inc. HTP' fuel. Hence this event was analyzed with Framatome Inc. HTP' fuel.

The RCS response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). The event was initiated from HFP conditions because it has the least margin to the DNBR limits, and the VHPT setpoint is automatically reset to track the current operating power level, resulting in a proportionally lower setpoint for a part-power condition.

The analysis considered two sets of cases. One set uses the least negative FTC and the most positive MTC, which correspond to BOC conditions. The other set uses the most negative FTC and the most negative MTC, which corresponds to EOC conditions. For both sets of cases, a range of reactivity insertion rates were analyzed, from very slow to fast, limited only by bank worth and maximum drive speed. This spectrum of cases ensures that the minimum DNBR is calculated for this event. The reactivity insertion rates also bound the reactivity insertion rate for a Boron Dilution For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-30 event starting from Mode 1 operating conditions. The analysis showed that the fuel SAFDLs are not violated. Overpressurization is not a concern in this event because the secondary is available and is not isolated until reactor trip. Pressurizer sprays and the PORVs are assumed to be available because the intent of the analysis is to maintain RCS pressure as low as possible to challenge the fuel SAFDL limits. The limiting cases indicated that the sprays are actuated, and the RCS pressure reaches the PORV setpoint. The RCS pressure decreases rapidly once the reactor trips.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

In particular, the CEA Swap reactivity insertion rates remain bounded by the range of rates used in the AOR.

The MDNBR for this event is greater than the correlation limit.

The peak LHGR during the event was shown to remain below the limit that precludes FCM.

5.2.4.3 Control Rod Misoperation (SRP 15.4.3, UFSAR 14.11)

The control rod misoperation event considered in the UFSAR is the CEA Drop event (UFSAR 14.11). It causes a redistribution of power which leads to a local augmentation of the peaking factor in the affected region of the core.

5.2.4.3.1 Event Description A control rod/bank drop event is initiated by a de-energized CEDM or another failure in the control rod system which causes a CEA to drop into the core. A dropped CEA is detected by either a position limit switch on each CEDM or by a reduction in power sensed by the ex-core detectors.

With the insertion of negative reactivity due to the dropped rod/bank, the core power decreases.

Moderator and Doppler temperature feedback, driven by a constant turbine generator load, cause the power to increase to close to its initial state. An increase in the radial peaking results from power redistribution due to the dropped rod/bank. This event is a challenge to DNB limits because of radial peaking augmentation together with near full power operating conditions.

5.2.4.3.2 Event Disposition and Justification The key parameters in the analysis of this event are the dropped CEA worth, the FTC and the MTC.

The rod worth and the reactivity coefficients can be affected by the introduction of Framatome Inc.

HTP' fuel. Hence this event was analyzed with Framatome Inc. HTP' fuel.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-31 The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). The worth of the dropped CEA determines the decrease in core power and decrease in RCS temperature. A strongly negative MTC (at EOC) will produce reactivity insertion, which could return the reactor to full power (since CCNPP has no automatic rod control and no turbine runback), with augmented radial peaking due to the dropped CEA. A lower worth CEA results in a higher resultant core power but a lower radial peaking augmentation. A higher worth CEA results in a lower resultant core power but a higher radial peaking augmentation. For this reason, a range of CEA worths were analyzed.

Protection against exceeding the fuel SAFDLs is provided by the initial steady-state DNB margin, the VHPT, and the TM/LP trip. Depending on the CEA worth, the event may be terminated by a reactor trip, or the reactor returning to a new steady-state power level.

The analysis considered CEA worths ranging from 10 pcm to 200 pcm. The event was initiated from HFP conditions with the most negative MTC value (corresponding to EOC conditions). The initial power decrease, and the consequent decrease in steam flow, causes the turbine control valves to open to maintain a constant load demand. The decrease in RCS temperature along with the negative MTC causes positive reactivity insertion and the reactor power starts to increase. The results showed that for all the cases analyzed, there is no reactor trip, and the reactor power returns to a new value slightly above the initial value before reaching a steady-state condition. The operator will then initiate a power reduction as necessary, dictated by the Technical Specifications. The analysis showed that the fuel SAFDLs are not violated.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

The MDNBR for this event is analyzed statistically on a cycle-by-cycle basis as a part of the DNB LCO barn setpoint verification (See Section 6.0).

The peak LHGR during the event was shown to remain below the limit to preclude FCM.

5.2.4.4 Startup of an Inactive Loop (SRP 15.4.4) 5.2.4.4.1 Event Description This event is initiated by the startup of an inactive primary coolant pump. The startup of an inactive pump can lead to an introduction of colder primary coolant into the reactor core. The lower coolant For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-32 temperature, together with a negative MTC, can cause an increase in core power and a degradation of DNB margin. Sufficient protection is available to reduce the consequences of this event.

5.2.4.4.2 Event Disposition and Justification The CCNPP Technical Specification LCO 3.4.4 requires all reactor coolant pumps (RCP) to be in operation in Modes 1 and 2. The RPS low flow trip function provides protection for the loss of motive power to an RCP, and the startup of a RCP is not allowed in Modes 1 and 2. Framatome Inc. is not responsible for the startup of an inactive RCP in lower mode operations (e.g., Pressurized Thermal Shock (PTS) concerns). Therefore, this event is not analyzed.

5.2.4.5 Flow Controller Malfunction (SRP 15.4.5)

The CCNPP Units do not have any flow control devices on the primary reactor coolant loops, so this event is not credible and is not analyzed.

5.2.4.6 CVCS Malfunction That Results in a Decrease in the Boron Concentration in the Reactor Coolant (SRP 15.4.6) 5.2.4.6.1 Event Description A boron dilution event can occur when primary grade water is added to the RCS via the CVCS during cold shutdown or refueling shutdown conditions.

The dilution of primary system boron adds positive reactivity to the core. This event can lead to an erosion of shutdown margin for subcritical initial conditions, or a slow power excursion for at-power conditions. A boron dilution at rated or power operating conditions behaves in a manner similar to a slow uncontrolled rod withdrawal transient (Section 5.2.4.2).

5.2.4.6.2 Event Disposition and Justification A boron dilution event can occur when unborated water is added to the RCS via the CVCS. Boron dilution with these systems is a manually initiated operation under strict administrative controls requiring operator surveillance with procedures limiting the rate and duration of the dilution. A boric acid blend system is available to allow the operator to match the makeup boron concentration to that of the RCS during normal charging.

One means of causing an inadvertent boron dilution is the opening of the primary water makeup control valve and failure of the CVCS or the operator to properly adjust the boron concentration For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-33 in the primary makeup water. The most limiting event is typically a malfunction which causes the delivery of pure water to the RCS by all available charging pumps.

The boron dilution analysis evaluates the time to criticality caused by the dilution of the primary system boron and subsequent loss of shutdown margin. The systems that are involved in a boron dilution event, depending on the mode of operation, are the RCS, the shutdown cooling system, and the CVCS. It should be noted that the important parameter of the RCS with one or more primary pumps in operation is the total mass inventory, not the flow rate.

Modes 2-6 are bounded by the analysis of record performed for the fuel transition. The analysis was performed using the instantaneous mixing model for operation with the RCPs and with the dilution front model for operation with SDC. The acceptance criterion for each mode of operation is met.

A boron dilution event initiated from Mode 1 is similar to a slow reactivity addition due to a CEA withdrawal.

Because the Control Element Assembly Withdrawal at Power event (SRP 15.4.2/UFSAR 14.2) is more challenging to the fuel SAFDLs, it bounds the boron dilution event and therefore no deterministic DNB or FCM analysis is needed.

5.2.4.7 Inadvertent Loading and Operation of a Fuel Assembly in an Improper Position -

Misload (SRP 15.4.7) 5.2.4.7.1 Event Description The misloaded assembly event is characterized by the loading of one or more fuel assemblies into improper locations and, where physically possible, with incorrect orientation. Fuel design and fabrication controls combined with plant refueling procedures minimize the likelihood of fuel loading errors. The incore monitoring system provides additional protection against fuel loading errors by detecting power distribution anomalies. Despite these safeguards, the potential exists that an undetected fuel loading error may occur and present a challenge to fuel rod failure limits.

The initial low-power flux map is the primary means used to determine if the core is loaded consistent with design. Therefore, the operability status of the incore detector system is a major component of the calculations used to detect fuel misloads.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-34 5.2.4.7.2 Event Disposition and Justification Misload analysis was not performed for the CEA Rod Swap Redesign. The event disposition and justification of the original Unit 2 Cycle 26 design - repeated without change below - remains applicable.

The analysis assumes a minimum number of ICI string locations (Table 7-1) will be operable during the BOC flux map.

The number of operable ICI string locations needed to detect all misloads (that would challenge peaking limits during the cycle) during the initial 30% power flux map is dependent upon the misloaded assembly detection criteria. The misload detection criteria are based on the maximum difference between measured and predicted reaction rates (detector signal), the maximum ratio of reaction rates in symmetric ICI strings and the number of detectors that must be available in a given region of the core. The detection criteria are as follows:

Measured-to-calculated power difference >15% or >0.15 RPD, whichever is greater

Symmetric ICI string ratio >1.10

All 5x5 arrays of fuel assemblies that contain 25 fuel assemblies must contain at least one operable detector segment on any axial level These detection criteria are compared against (1) the maximum difference between measured and predicted reaction rates, (2) the maximum ratio of reaction rates in symmetric ICI strings measured, and (3) the ICI strings needed to detect a misload during the initial 30% flux map. If the measured values exceed the criteria, then further evaluation of the flux map for a potential misload is required.

The MDNBR portion of the event was evaluated to address changes in cycle-specific neutronic parameters. The maximum allowed FrT to meet, but not exceed, the HTP MDNBR limit was determined. This maximum allowed FrT ensures that FrT values at or below this value will meet DNBR safety limits.

The FCM portion of the event was evaluated to address changes in cycle-specific neutronics parameters. The maximum allowed FQ to meet, but not exceed, the FCM limit was determined.

This maximum allowed FQ ensures that FQ values at or below this value will meet the FCM limit.

Adherence to the DNBR and FCM SAFDLs ensures that fuel failures will not occur as a result of undetectable misloads.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-35 5.2.4.8 Spectrum of Control Rod Ejection Accidents (SRP 15.4.8, UFSAR 14.13) 5.2.4.8.1 Event Description The Control Rod Ejection event is initiated by a postulated rupture of a control rod drive mechanism housing. Such a rupture allows the full system pressure to act on the drive shaft, which ejects its control rod from the core. The consequences of the mechanical failure are a rapid positive reactivity insertion and an increase in radial power peaking, which could possibly lead to localized fuel rod damage.

Doppler reactivity feedback mitigates the power excursion as the fuel begins to heat up.

Subsequently, the VHPT signal provides reactor trip. This is backed up by the TM/LP trip. Although the initial increase in power occurs too rapidly for the scram rods to have any effect on the power during that portion of the transient, the scram negative reactivity insertion does affect the fuel temperature and fuel rod cladding surface heat flux.

5.2.4.8.2 Event Disposition and Justification The key parameters in the analysis of this event are the reactivity insertion rate due to rod motion, the FTC and the MTC. The rod worth, post-ejection power peaking, and the FTC can be affected by the introduction of Framatome Inc. HTP' fuel. Hence this event was analyzed with Framatome Inc. HTP' fuel.

The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 were used as input to the DNBR analysis (Reference 4). HFP and HZP initial conditions were considered because of the strong impact of the neutronic parameters on this event. Consistent with design basis of CCNPP, the analysis assumed offsite power is available. The VHPT signal is expected to initiate reactor trip for this event. The VHPT setpoint is dependent on the initial power level. To cover the variation in the setpoint as well as in the neutronic parameters, the analysis was conducted at BOC and EOC fuel conditions, at HFP and HZP. The analysis was focused on minimizing DNBR and challenging the fuel SAFDLs and the energy deposition limit. The Pressurizer Spray and the PORVs were assumed available to minimize RCS pressure. Key parameters in the analysis are:

Rod worth: Upper bound values were used corresponding to HFP or HZP conditions to maximize the rate of power increase.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-36

Fuel-cladding gap heat transfer coefficient: Upper bound values were used corresponding to BOC or EOC fuel conditions to minimize the Doppler feedback effect and maximize the rod surface heat flux (which lags the core power). The high gap heat transfer coefficient decreases the thermal inertia of the fuel rod.

The results of the analysis showed that the fuel SAFDLs are not violated.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

In particular, the CEA Swap rod worth remains bounded by the values used in the AOR.

The MDNBR for this event is greater than the correlation limit. No fuel failure as a result of MDNBR is predicted.

The peak LHGR during the event was shown to remain below the limit that precludes FCM. No fuel failure as a result of FCM is predicted.

The deposited enthalpy portion of the rod ejection accident has been evaluated with the procedures developed in the Generic Rod Ejection Analysis (Reference 13). The ejected rod worths and hot pellet peaking factors were calculated using the PRISM code. The calculated maximum total deposited enthalpy is 200 cal/gm (this limit has been set by the NRC as a condition of the transition to Framatome Inc. fuel).

5.2.4.9 Spectrum of Rod Drop Accidents (BWR) (SRP 15.4.9)

This is related to BWR safety analysis and, therefore, is not applicable to CCNPP.

5.2.5 Increases in Reactor Coolant System Inventory (SRP 15.5) 5.2.5.1 Inadvertent Operation of the ECCS That Increases Reactor Coolant Inventory (SRP 15.5.1)

This event is not applicable to CCNPP. The event could be initiated by a spurious start of the ECCS pumps or an inadvertent SI signal. A spurious start of the ECCS would have no effect since the shutoff head for the HPSI system (about 1473 psia) is much less than the normal RCS operating pressure (2250 psia). Excessive Charging is discussed in Section 5.2.5.2 below.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-37 5.2.5.2 CVCS Malfunction That Increases Reactor Coolant Inventory (SRP 15.5.2, UFSAR 14.25) 5.2.5.2.1 Event Description The excessive charging event is assumed to occur by inadvertent operation of charging flow. It is evaluated with a high initial pressurizer level to ensure that the operator has at least 15 minutes after the high pressurizer alarm to take corrective action and terminate the pressurizer level increase before it is filled completely with liquid. This ensures that the PORVs and PSVs do not see liquid carryover if and when they open, which ensures that they will reseat properly.

5.2.5.2.2 Event Disposition and Justification The key parameters in this event are plant system parameters - the initial pressurizer level and uncertainty, the charging flow rate, and the letdown flow rate. These parameters remain unchanged with the introduction of Framatome Inc. HTP' fuel. Hence the event was not reanalyzed for fuel transition.

Constellation is expected to verify that the identified plant changes do not impact the Analysis of Record.

5.2.6 Decrease in Reactor Coolant Inventory (SRP 15.6) 5.2.6.1 Inadvertent Opening of a PWR Pressurizer Pressure Relief Valve (SRP 15.6.1, UFSAR 14.8) 5.2.6.1.1 Event Description This is classified in the UFSAR as an RCS Depressurization Event, defined as a rapid, uncontrolled decrease in RCS pressure other than a LOCA. Inadvertent opening of the PSVs or PORVs during steady-state operation would result in an RCS Depressurization Event. This event results in a loss of RCS coolant inventory and a fairly rapid RCS depressurization. The core power increases (when the moderator temperature coefficient is positive) in response to positive moderator density feedback caused by the depressurization. The RPS will automatically function to scram the reactor, terminating the challenge to the DNB SAFDL. Reactor scram is expected to occur on a TM/LP trip.

5.2.6.1.2 Event Disposition and Justification The event is principally of concern in the short term because of the DNBR challenge due to depressurization before scram. The depressurization has little effect on core power or primary For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-38 temperatures. The most limiting RCS depressurization event at HFP is an inadvertent opening of both PORVs. The two PORVs have a larger relieving capacity than one PSV.

The key parameters for this event are the initial operating conditions, the capacity of the PORVs, and the reactor trip setpoints, delays and uncertainties. Although these parameters are not impacted by the transition to Framatome Inc. HTP' fuel, differences in the fuel rod and assembly design may introduce a perturbation in the MDNBR analysis associated with this event. As such, the acceptance criteria specified for this event must be evaluated to support the fuel transition.

Consequently, this event was reanalyzed with Framatome Inc. HTP' fuel. The reactor coolant system response was determined using the approved S-RELAP5 non-LOCA analysis methodology (Reference 3). The transient core thermal-hydraulic conditions calculated by S-RELAP5 are used as input to the DNBR analysis (Reference 4).

The analysis considered a bounding case starting at BOC HFP initial conditions, with a conservative MTC value (most positive), conservative PORV discharge capacity (rated value plus 20%), and maximum delays and uncertainties applied to the reactor trip setpoints. Offsite power was assumed available, hence the SG is available to remove heat, to minimize the RCS pressure. The analysis showed reactor trip occurring when the RCS pressure reaches the TM/LP trip setpoint. The transient core thermal-hydraulic parameters are used to conduct the DNBR analysis using a DNB correlation appropriate for Framatome Inc. HTP' fuel. The results showed that the fuel SAFDLs are not violated.

The transient response AOR bounds the core design, so no re-analysis of this event was required.

This event is protected by the TM/LP trip, which is verified each cycle.

This event does not challenge the FCM limit, therefore peak LHGR was not evaluated.

5.2.6.2 Radiological Consequences of the Failure of Small Lines Carrying Primary Coolant Outside of Containment (SRP 15.6.2)

This event is not part of Framatome Inc.s scope. Therefore, this event is not analyzed.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-39 5.2.6.3 Radiological Consequences of Steam Generator Tube Failure (SRP 15.6.3, UFSAR 14.15) 5.2.6.3.1 Event Description This incident occurs when a steam generator tube fails, causing a leakage of coolant from the primary system to the secondary system. The leakage results in a depletion of primary coolant, a reduction of primary system pressure and a release of fission products to the main steam system.

The consequences of this event are maximized for a rated power initial condition due to the amount of stored energy and decay heat that must be removed prior to bringing the two systems to an equilibrium pressure state.

The SGTR event is initiated by a double-ended break of a single steam generator tube. Coolant from the RCS begins to escape through the break, driven by the pressure differential between the RCS and the SG secondary side, increasing the inventory and pressure in the affected SG.

As the break flow begins to depressurize the RCS, the charging pumps activate in order to make-up the lost inventory and pressurizer heaters energize on decreasing pressure. If the RCS inventory and pressure are stabilized via the charging pumps, no reactor trip will occur. However, if the break flow exceeds the capacity of the charging pumps, the RCS pressure and inventory will continue to decrease resulting in a reactor trip on a low RCS pressure signal (TM/LP or Low Pressurizer Pressure). Following the reactor trip, the turbine will trip and, in the case where offsite power is lost, the reactor coolant pumps will coast down, and make-up flow will terminate until emergency diesel generator power is available (if charging pumps are connected to the diesels). If offsite power is available, a fast transfer to the offsite power will keep the reactor coolant pumps running and the make-up flow available.

The loss of offsite power results in the loss of condenser vacuum and the steam dump to condenser valves are closed to protect the condenser. The continued mass and energy transfer between the RCS and secondary side results in an increase in the affected SG pressure and discharge to the atmosphere via the MSSVs and ADVs.

As the RCS pressure continues to decrease, a low pressurizer pressure signal activates the SIAS.

The emergency diesels start and HPSI flow begins once the shutoff head of the HPSI pumps has been reached. The RCS pressure gradually increases following the initiation of the SIAS and the HPSI flow and stabilizes at a pressure near that of the HPSI pump head. The SI flow offsets the For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-40 coolant mass loss due to the ruptured tube, and results in slowing the depressurization of the RCS.

The higher RCS pressure increases the primary to secondary leak rate.

The operators will take a series of actions to regain control of the plant systems and to bring the RCS to a condition allowing for initiation of the RHR system.

5.2.6.3.2 Event Disposition and Justification The key parameters for this event are:

Loss of offsite power and time of reactor trip.

Charging and HPSI system flow (maximum to keep RCS pressure high and maximize primary-to-secondary break flow).

The single active failure identified in the licensing basis.

Operator actions consistent with plant EOPs.

SG blowdown system flow.

Decay heat.

Ruptured SG tube location and break flow rate (highest location and maximum flow, to maximize radiological release).

Steam flow rate through MSSVs and ADVs.

Fraction of break flow that flashes in the SG (maximum, to maximize radiological release).

Duration of SG tube bundle uncovery, if any.

These key parameters are all plant system related and not affected by the transition to Framatome Inc. HTP' fuel. Therefore, the event was not reanalyzed for fuel transition. The input assumptions for the radiological analysis of the SGTR event in the AOR are conservative and are also not affected by all the identified plant changes. Hence the radiological release remains bounded by the analysis of record.

Constellation is expected to verify that the radiological source term remains unaffected.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-41 5.2.6.4 Radiological Consequences of a Main Steam Line Failure Outside Containment (BWR) (SRP 15.6.4)

This event is applicable only to BWRs and therefore is not applicable to CCNPP.

5.2.6.5 Loss of Coolant Accidents Resulting from a Spectrum of Postulated Piping Breaks within the Reactor Coolant Pressure Boundary (SRP 15.6.5) 5.2.6.5.1 Event Description A LOCA is initiated by a breach in the RCS pressure boundary. A range of break sizes from small leaks up to a complete double-ended severance of an RCS pipe must be considered. Typically, these breaks are classified as small and large breaks.

The purpose of the LOCA analyses is to demonstrate that the criteria stated in 10 CFR 50.46(b)

(1-4) (Reference 19) are met.

Framatome NRC-approved methodologies for analyzing the consequences of this event are documented in Reference 5 for LBLOCA and References 6 and 18 for SBLOCA.

5.2.6.5.2 Large Break LOCA The LBLOCA AOR is documented in Reference 7 with RAI documented in Reference 8. The licensing criteria stated in Reference 7 Section 3.0, which support 10 CFR 50.46(b)

(Reference 19), continue to be met for Cycle 26 with the CEA Rod Swap Redesign. The limiting case PCT and oxidation results from Reference 7 are listed in Table 5-2.

Table 5-2 RLBLOCA AOR Limiting Results Parameter AOR Value PCT

)

Maximum Total Local Oxidation 1.76%

Total Core-Wide Oxidation 0.011%

5.2.6.5.3 Small Break LOCA The SBLOCA AOR is documented in Reference 9. The licensing criteria stated in Reference 9 Section 2.0, which support 10 CFR 50.46(b) (Reference 19), continue to be met for Cycle 26 with For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-42 the CEA Rod Swap Redesign. The limiting case PCT and oxidation results from Reference 9 are listed in Table 5-3.

Table 5-3 SBLOCA AOR Limiting Results Parameter AOR Value PCT 1648)

Maximum Total Local Oxidation 3.50%

Total Core-Wide Oxidation 0.009%

5.2.6.5.4 Condition Reports There are no new Condition Reports under 10 CFR 50.46 reporting identified for LBLOCA or SBLOCA AORs (References 7 and 9) for Cycle 26 with the CEA Rod Swap Redesign. A summary of the Condition Reports with impact on PCT is presented in Table 5-4. The total PCT shown is the total accumulated from Framatome Condition Reports for potential reporting under 10 CFR 50.46. Only Condition Reports with PCT changes greater than zero are shown.

In addition to the condition reports, PCT assessments for potential reporting under 50.46 requirements were also checked. For Cycle 24, a technical evaluation to assess the potential impacts of the PROtect LTA design to the Calvert Cliffs LOCA licensing bases was performed DQGDERXQGLQJ3&7HVWLPDWHIRUWKHSRWHQWLDOLPSDFWVZDVGHWHUPLQHG7KHHYDOXDWLRQUHVXOWHG

LQ/2&$3&7SHQDOWLHVRI [ ] )IRU6%/2&$DQG [ ] )IRU5/%/2&$These PCT penalties are also applicable to Calvert Cliffs operating Unit 2 Cycle 26 with the CEA Rod Swap Redesign.

Table 5-4 Summary of LOCA PCT Penalties For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-43 5.2.6.5.5 Post-LOCA Shutdown Condition

[

] As such, post-LOCA criticality is precluded, and post-LOCA long-term cooling has been confirmed.

5.2.7 Radioactive Releases from a Subsystem or Component (SRP 15.7) 5.2.7.1 Waste Gas System Failure (SRP 15.7.1, UFSAR 14.22)

The results of this event are not dependent on the fuel bundle design or primary system conditions.

The UFSAR analysis remains the bounding analysis for this event (Constellation to verify).

5.2.7.2 Radioactive Liquid Waste System Leak or Failure (Release to Atmosphere)

(SRP 15.7.2, UFSAR 14.23)

The results of this event are not dependent on the fuel bundle design or primary system conditions.

The UFSAR analysis remains the bounding analysis for this event (Constellation to verify).

5.2.7.3 Postulated Radioactive Releases due to Liquid-Containing Tank Failures (SRP 15.7.3)

This event is not part of the UFSAR. No evaluation is required.

5.2.7.4 Radiological Consequences of Fuel Handling Accident (SRP 15.7.4, UFSAR 14.18) 5.2.7.4.1 Event Description A fuel handling accident occurs when a fuel assembly is damaged during refueling operations such that fuel rods are ruptured resulting in a release of radioactivity. The inventory of radioactive fission products is determined by the exposure and power level of the assemblies or fuel rods.

5.2.7.4.2 Event Disposition and Justification The results of this event are not dependent on the fuel bundle design or primary system conditions.

The UFSAR analysis remains the bounding analysis for this event (Constellation to verify source term remains bounding).

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-44 5.2.7.5 Spent Fuel Cask Drop Accidents (SRP 15.7.5, UFSAR 5.6.1.5)

This event is caused by a spent fuel cask being inadvertently dropped on the spent fuel pool floor, and the possibility of damage to the floor. The results of this event are not dependent on the fuel bundle design or primary system conditions. The UFSAR analysis remains the bounding analysis for this event (Constellation to verify source term remains bounding).

5.2.7.6 Spent Fuel Pit Water Loss (SRP 15.7.6)

This event is not part of the UFSAR. No evaluation is required.

5.2.8 Anticipated Transients Without Scram (SRP 15.8, UFSAR 7.11)

These are anticipated operational occurrences followed by the failure of the reactor trip portion of the reactor protection system. These events are protected against by a protection system that automatically initiates the operation of other systems to mitigate the event and ensure that the fuel SAFDLs are satisfied (outside Framatome Inc. scope).

5.3 Other Analyses Several events are contained in the UFSAR that are not part of the Standard Review Plan, and are not analyzed by Framatome Inc.

5.3.1 Control Room Habitability (Constellation responsibility) 5.3.2 Equipment Qualification Source Terms (Constellation responsibility) 5.3.3 Low Temperature Overpressurization Protection System (Constellation responsibility) 5.3.4 Pressure Isolation Valve Testing (Constellation responsibility) 5.3.5 Alternate Source Term (Constellation responsibility)

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-45 5.3.6 Turbine Generator Overspeed Incident (UFSAR 14.19) 5.3.6.1 Event Description The Turbine-Generator Overspeed Incident is postulated to be caused by a failure of components that control admission of steam to the turbine resulting in destructive shaft rotational speed, which may yield turbine-generator produced missiles.

This incident is evaluated to demonstrate the adequacy of the plant design. The NRC-preferred method of protecting against turbine missiles is to ensure that turbine missile generation probability, P1, is maintained at a value of less than 10-5 per year (UFSAR Section 5.3.1).

5.3.6.2 Event Disposition and Justification The key parameters for this incident are:

NSSS Steam Flow

Turbine-Generator Control Systems Per UFSAR Section 5.3.1.2, the AOR for this event concluded that the missile generation probability for both of the CCNPP Units were below the acceptance criteria. The event behavior is predominantly a function of the turbine generator control system and steam flow. Therefore, small perturbations in parameters such as the core pressure drop, core bypass flow fraction, core inlet flow distribution, and reactivity feedback do not impact the parameters of interest in assessing the acceptance criteria. The plant system characteristics that potentially impact the key parameters listed for this incident remain unchanged for both the transition fuel cycle, and the full core implementation of Framatome Inc. fuel at Calvert Cliffs (Constellation to verify). The cause of the event and the parameters which control the consequences of the event are unchanged from or bounded by the assessment presented in UFSAR Section 5.3.1.2. Therefore, an analysis of the Turbine-Generator Overspeed Incident is not required to support the transition to Framatome Inc. HTP' fuel.

The AOR bounds the core design, so no re-analysis of this event was required.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-46 5.3.7 Containment Response (UFSAR 14.20) 5.3.7.1 Event Description The Containment Structure encloses the primary and secondary plant and is the final barrier against the release of significant amounts of radioactive fission products in the event of an accident. The Containment Structure must be capable of withstanding the pressure and temperature conditions resulting from a postulated LOCA or MSLB accident. While other events, such as a feedwater line break also discharge mass and energy to Containment, the LOCA and MSLB have been confirmed to be the two most severe inside containment events with respect to maximizing the peak containment pressure and temperature.

7KH &&133 FRQWDLQPHQW KDV D GHVLJQ SUHVVXUH DQG WHPSHUDWXUH RI  SVLJ DQG )

respectively. These containment design values were selected as a result of the original analysis of the LOCA. While 50 psig reflects a maximum pressure in the vapor space, the design temperature RI ) LV D VWUXFWXUDO OLPLW RI WKH FRQFUHWH ZDOO LQQHU VXUIDFH DQG WKH VWHHO OLQHU SODWH 7KH

acceptance criterion for the containment response analysis is that pressure and temperature remain below these limits.

5.3.7.2 Event Disposition and Justification Per UFSAR Tables 14.20-2 and 14.20-11, the mass and energy release rates in the AOR for this event are based on an initial core power level up to 2754 MWth. This value is not impacted by the transition to Framatome Inc. fuel and remains bounding. The event behavior is predominantly a function of the stored energy in the reactor coolant and steam generators. Therefore, small perturbations in parameters such as the core pressure drop, core bypass flow fraction, core inlet flow distribution, and reactivity feedback do not impact the parameters of interest in assessing the acceptance criteria. The plant system characteristics that potentially impact the key parameters listed for this analysis remain unchanged. The cause of the event and the parameters which control the consequences of the event are unchanged from or bounded by the analysis of record presented in UFSAR Section 14.20. Therefore, a re-analysis of the Containment Response event is not required to support the transition to Framatome Inc. HTP' fuel.

Constellation is expected to confirm the above assessment and verify that identified plant changes do not impact the analysis of record.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-47 5.3.8 Maximum Hypothetical Accident (UFSAR 14.24)

(Constellation responsibility) 5.3.9 Incore Instrument Melt (Constellation responsibility) 5.3.10 Station Blackout (Constellation responsibility) 5.3.11 Fuel Storage Rack Criticality (Constellation responsibility)

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-48 Table 5-5 Disposition of Events Summary SRP Event UFSAR Event Condition Event Description Disposition 15.1.1 14.7 II (AOO)

Decrease in Feedwater Temperature

System transient response Bounded by AOR

MDNBR Bounded by 14.4 15.1.2 14.7 II (AOO)

Increase in Feedwater Flow Bounded by 14.7 (Decrease in Feedwater Temperature) 14.12 II (AOO)

Increase in Feedwater Flow to one Steam Generator (Asymmetric Excess Feedwater)

Bounded by 14.12 (Asymmetric Loss of Load) 15.1.3 14.4 II (AOO)

Increase in Steam Flow (Excess Load)

System transient response Analyzed2

MDNBR Verified in Setpoints

FCM/LHGR Verified in Setpoints 15.1.4 14.12 II (AOO)

Inadvertent Opening of a Steam Generator Relief or Power Operated Relief Valve (Asymmetric Excess Load)

Bounded by 14.12 (Asymmetric Loss of Load) 15.1.5 14.14 IV (PA)

Main Steam Line Break Event

System transient response Analyzed2

AST parameters Bounded by AOR1

MDNBR (Pre-Scram)

Analyzed

MDNBR (Post-Scram)

Analyzed

FCM/LHGR (Pre-Scram)

Analyzed

FCM/LHGR (Post-Scram)

Analyzed

Reactivity Verification (Post-Scram)

Analyzed 15.2.1 14.5 II (AOO)

Loss of External Electrical Load Bounded by AOR 15.2.2 14.5 II (AOO)

Turbine Trip Bounded by 14.5 15.2.3 14.5 II (AOO)

Loss of Condenser Vacuum Bounded by 14.5 15.2.4 14.5 II (AOO)

Inadvertent Closure of Main Steam Isolation Valves Bounded by 14.5 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-49 SRP Event UFSAR Event Condition Event Description Disposition 14.12 II (AOO)

Inadvertent Closure of Main Steam Isolation Valve to one Steam Generator (Asymmetric Loss of Load)

System transient response Bounded by AOR

MDNBR Bounded by 14.14

FCM/LHGR Bounded by 14.14 15.2.5 14.5 II (AOO)

Steam Pressure Regulator Malfunction or Failure that Results in Decreasing Steam Flow Bounded by 14.5 15.2.6 14.10 II (AOO)

Loss of Non-Emergency AC Power to the Station Auxiliaries

With turbine trip, short-term Bounded by 14.9

With turbine trip, long-term Bounded by AOR1 15.2.7 14.6 II (AOO)

Loss of Normal Feedwater Flow

Peak primary pressure Bounded by AOR

Peak secondary pressure

Pressurizer level swell

Minimum SG inventory 14.12 II (AOO)

Loss of Normal Feedwater to one Steam Generator (Asymmetric Loss of Feedwater)

Bounded by AOR1 15.2.8 14.26 IV (PA)

Feedwater System Pipe Break Bounded by AOR 15.3.1 14.9 II (AOO)

Loss of Forced Reactor Coolant Flow

System transient response Bounded by AOR

MDNBR Verified in Setpoints, Analyzed 15.3.2 N/A II (AOO)

Flow Controller Malfunction N/A 15.3.3 14.16 IV (PA)

Reactor Coolant Pump Shaft Seizure (Locked Rotor)

System transient response Bounded by AOR

AST parameters Bounded by AOR1

MDNBR Analyzed 15.3.4 N/A IV (PA)

Reactor Coolant Pump Shaft Break N/A For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-50 SRP Event UFSAR Event Condition Event Description Disposition 15.4.1 14.2 II (AOO)

Uncontrolled RCCA Bank Withdrawal from Subcritical or Low Power Startup

System transient response Bounded by AOR with plant operating restrictions (see Note 3)

MDNBR Bounded by 14.2 (at Power)

Peak temperature Bounded by 14.2 (at Power) 15.4.2 14.2 II (AOO)

Uncontrolled RCCA Bank Withdrawal at Power

System transient response Bounded by AOR

MDNBR Analyzed

FCM/LHGR Analyzed 15.4.3 14.11 II (AOO)

RCCA Misoperation - Dropped RCCA

System transient response Bounded by AOR

MDNBR Verified in Setpoints

FCM/LHGR Analyzed 15.4.4 14.1 II (AOO)

Startup of an Inactive Reactor Coolant Loop at an Incorrect Temperature N/A For lower mode operation, Outside Framatome Inc.s scope 15.4.5 N/A Recirculation Loop at Incorrect Temperature or Flow Controller Malfunction N/A 15.4.6 14.3 II (AOO)

CVCS Malfunction that Results in a Decrease in Boron Concentration in the Reactor Coolant

MODE 1 (MDNBR & FCM/LHGR)

Bounded by 14.2 (at Power)

Time to Criticality (MODES 2-6)

Bounded by AOR 15.4.7 N/A III (PA)

Inadvertent Loading of a Fuel Assembly into the Improper Location - Misload

MDNBR Analyzed

FCM/LHGR Analyzed 15.4.8 14.13 IV (PA)

Spectrum of RCCA Ejection Accidents

System transient response Bounded by AOR

AST parameters Bounded by AOR1

MDNBR Analyzed For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-51 SRP Event UFSAR Event Condition Event Description Disposition

Peak temperature Analyzed

Deposited enthalpy Analyzed 15.4.9 N/A Spectrum of Rod Drop Accidents N/A 15.5.1 N/A II (AOO)

Inadvertent Operation of ECCS N/A 15.5.2 14.25 II (AOO)

CVCS Malfunction that Increases Reactor Coolant Inventory Bounded by AOR1 15.6.1 14.8 II (AOO)

Inadvertent Opening of Pressurizer Safety or Power Operated Relief Valve

System transient response Bounded by AOR

MDNBR Verified in Setpoints 15.6.2 N/A III (PA)

Radiological Consequences of the Failure of Small Lines Carrying Primary Coolant Outside of Containment Outside Framatome Inc.s scope 15.6.3 14.15 IV (PA)

Steam Generator Tube Rupture

Transient response Bounded by AOR1

AST parameters Bounded by AOR1 15.6.4 N/A Spectrum of BWR Steam Piping Failures Outside Containment N/A 15.6.5 14.17.3 IV (PA)

Small Break Loss-of-Coolant Accidents

Transient response Analyzed

AST parameters Bounded by AOR1 14.17.2 IV (PA)

Large Break Loss-of-Coolant Accidents

Transient response Analyzed

AST parameters Bounded by AOR1

Post-LOCA Criticality Analyzed 15.7.1 14.22 Radioactive Waste Gas System Leak or Failure Outside Framatome Inc.s scope 15.7.2 14.23 Liquid Waste System Leak or Failure Outside Framatome Inc.s scope 15.7.3 N/A III (PA)

Postulated Radioactivity Releases Due to Liquid Tank Failure N/A 15.7.4 14.18 IV (PA)

Design Basis Fuel Handling Accidents Outside Framatome Inc.s scope For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 5-52 SRP Event UFSAR Event Condition Event Description Disposition 15.7.5 5.6.1.5 III (PA)

Spent Fuel Cask Drop Accidents Outside Framatome Inc.s scope 15.7.6 N/A Spent Fuel Pit Water Loss N/A 15.8 7.11 Anticipated Transients Without Scram Outside Framatome Inc.s scope Control Room Habitability Outside Framatome Inc.s scope Equipment Qualification Source Terms Outside Framatome Inc.s scope Low Temperature Overpressurization Protection System Outside Framatome Inc.s scope Pressure Isolation Valve Testing Outside Framatome Inc.s scope 14.19 Turbine Generator Overspeed Incident Bounded by AOR1 14.20 Containment Response Confirmation by Constellation required 14.24 Maximum Hypothetical Accident Outside Framatome Inc.s scope Incore Instrument Melt Outside Framatome Inc.s scope Alternate Source Term Outside Framatome Inc.s scope 8.4 8.4 Station Blackout (SBO)

Outside Framatome Inc.s scope Fuel Storage Rack Criticality Outside Framatome Inc.s scope 1 The analysis of record for this event remains the Westinghouse (or other vendor) analysis. Constellation is expected to ensure that the plant changes identified in Table 5-1 do not impact the Westinghouse (or other vendor) Analysis of Record.

2 The transient response AOR was previously re-analyzed with [

]

3 Plant operation will be restricted to Mode 2 power levels that exclude initial conditions which may lead to a fast transient (see discussion in Section 5.2.4.1.2)

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-1 6.0 TRIP SETPOINT VERIFICATION The analytical methodology for determining or verifying the operating limits is detailed in each respective subsection and References 4 and 10. The Framatome Inc. setpoint analyses verify the validity of the current trip setpoints.

6.1 Reactor Protection System The RPS is designed to ensure that the reactor is operated in a safe and conservative manner, in accordance with the criteria established in 10 CFR 50, Appendix A. The LSSS functions, along with administratively applied LCO restrictions on reactor system parameters, define the limits for automatic RPS action to ensure that the SAFDLs are not exceeded for basis AOO events and during steady-state operation. The LSSS and LCO parametric values are presented in the following sections.

6.2 Specified Acceptable Fuel Design Limits The specific limits used to protect the fuel SAFDLs are:

1.

An LHGR limit to protect the FCM SAFDL. This is used such that the most limiting pin in the core is protected throughout the cycle, with a 95% probability.

2.

An upper 95/95 bound on the HTP DNB correlation, to protect the DNB SAFDL. This is defined such that the most limiting pin in the core does not experience DNB, at a 95%

probability, with 95% confidence.

An analysis was performed to determine the maximum LHGR limit that can be supported. The DQDO\VLVUHVXOWVLQGLFDWHWKDW)&0ZLOOQRWRFFXUIRU/+*5 [

] kW/ft in the UO2 rods, which implicitly cover all rods in the core.* However, a licensing condition imposed by the NRC specifies a limiting value of 21.0 kW/ft for the maximum LHGR limit.

It is noted that reload fuel that contains gadolinia bearing fuel rods will, for a given LHGR, operate with a higher fuel temperature and will consequently have a lower FCM limit. The FCM limit verification explicitly models the gadolinia bearing fuel rods in determining the LHGR limit.

The HTP critical heat flux correlation (Reference 4) is used in all thermal margin analyses.

The FCM limit is established for UO2 fuel rods such that FCM is precluded for all fuel rod types.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-2 6.3 Limiting Safety System Settings 6.3.1 Local Power Density The LPD (sometimes referred to as Axial Power Distribution - APD) trip limit defines the set of the limiting values of core power level versus ASI that will produce a reactor trip to protect the FCM LHGR limit. The correlation between allowed core power level and peripheral ASI is determined using methods which take into account the total calculated power peaking, and the measurement and calculation uncertainties associated with this peaking.

In the analysis for this trip function, postulated axial power distribution cases are examined to establish bounding values of FQ versus ASI. These cases are generated in a manner consistent with that discussed in Reference 10. Statistical methods are employed to account for the uncertainties in the parameters that are given in Table 6-1 and Table 6-4.

The peak LHR in the core occurs at the position of the maximum FQ, which is the ratio of the maximum to the average LHR in the core. FQ is determined by a three-dimensional neutronics methodology (Reference 2).

The LPD LSSS calculation verifies the existing LPD LSSS COLR barn for continued applicability.

The LPD LSSS COLR barn is reproduced in Figure 6-1. Figure 6-2 shows the LPD LSSS Barn used in the analysis. This barn conservatively bounds the values obtained from the COLR barn by accounting for [

]

The results in Figure 6-2 demonstrate that all the flyspeck FCM LHGR power points lie outside the LPD LSSS barn, thus, the adequacy of the existing LPD LSSS function is demonstrated.

6.3.2 Thermal Margin/Low Pressure The TM/LP trip protects against the occurrence of DNB and hot leg saturation during steady-state operations and for trip design basis AOOs. This reactor trip system monitors primary system pressure, core inlet temperature, core power and ASI. A reactor trip occurs when primary system For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-3 pressure falls below the maximum of the variable pressure, Pvar, or a fixed preset floor pressure, Pfloor. The Pvar function is given by:

Pvar = [

] [$ $6, [45 4  [

] x Tin - [

]

[psia]

in which Q is the higher of the thermal power and the nuclear flux power, Tin is the inlet temperature in F and A1 and QR1 (trip coefficient functions) are shown in Figure 6-3 and Figure 6-4, respectively. The COLR A1 function is shown in Figure 6-3 (a). For analysis, [

] The analysis A1 function is shown in Figure 6-3 (b). The Pfloor setting used in the cycle-specific analysis was 1829 psia.

A statistical setpoint methodology (Reference 10) is used to verify the adequacy of the existing TM/LP trip. The methodology for the TM/LP trip accounts for uncertainties in core operating conditions, HTP DNB correlation uncertainties, and uncertainties in power peaking. The uncertainties and biases presented in Table 6-1 through Table 6-4 are included in the verification of the TM/LP trip. The Framatome Inc. criterion is consistent with the SRP requiring that DNB be avoided with 95% probability at a 95% confidence level.

Positive pressure margin protection is provided by the existing trip at all postulated statepoints accessible by the trip, verifying that the current TM/LP setting remains applicable.

6.3.3 Additional Trip Functions In addition to the LPD and TM/LP trip functions, other reactor system trips have been determined to provide input to the setpoint verification. The setpoints for these trips are shown in Table 6-5.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-4 6.4 Limiting Conditions for Operation 6.4.1 DNB Monitoring The DNB LCO is designed to protect the DNB SAFDL against two categories of AOOs events:

(1) those requiring initial steady-state margin to the SAFDL, and (2) those requiring a combination of initial steady-state margin to the SAFDL and an RPS function. [

]

The DNB LCO calculation verifies the existing DNB LCO COLR barn for continued applicability.

The DNB LCO COLR barn is reproduced in Figure 6-5. Figure 6-6 shows the DNB LCO Barn used in the analysis which is obtained from the COLR barn by accounting for [

]

The method used to verify the DNB LCO involved simulation of the LOCF transient using the core thermal-hydraulic code XCOBRA-IIIC (Reference 11) to determine the DNB power corresponding to the upper 95/95-bound on the HTP correlation, as a function of ASI. The uncertainties listed in Table 6-6 and Table 6-7 are applied using the methodology described in Reference 10. The flyspeck results of the statistical analyses for the LOCF transient are shown in Figure 6-6.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-5

[

]

The analysis verifies that margin exists for the DNB LCO analysis thus, demonstrating the adequacy of the DNB LCO function.

6.4.2 Linear Heat Rate Monitoring In the event that the incore detector system is not in operation, the LHR is monitored via the excore nuclear detectors and observing a restricted allowable operational space defined by the LPD LCO. The LPD LCO limits core power so that the LHR LCO based on LOCA considerations is not exceeded. The LPD LCO protects the LOCA PLHR limit specified in Table 4-1.

The LPD LCO barn is shown in Figure 6-7. This corresponds to an updated barn with respect to the one originally provided in the COLR. This update was required in order to obtain positive margin in the LPD LCO analysis. The updated LPD LCO barn is intended specifically for the CEA swapped condition in Cycle 26 and it is more conservative otherwise. Figure 6-8 shows the LPD LCO barn used in the analysis which is obtained from the updated COLR barn by accounting for

[

] In the LPD LCO calculation the analysis barn was first identified and the updated COLR barn was determined from the formula above. The barn is extended to 20% power to match the previous COLR barn. While the ASI values of the analysis barn are smaller than the ASI values of the COLR barn, the use of the analysis barn coupled with the ASI uncertainty is conservative.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-6 To verify the LPD LCO, the nominal power corresponding to the LOCA LHR limit is calculated for a large set of axials (with various ASI and FQ). The nominal margin between this LOCA LHR power and the maximum allowed power defined by the LPD LCO barn is then [

] and the methods described in Reference 10. The results of the analysis are shown in Figure 6-8. All flyspeck points corresponding to the LOCA LHR lie outside of the LPD LCO barn, thus demonstrating the adequacy of the LPD LCO function.

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-7 Table 6-1 Uncertainties Applied in LPD LSSS Verifications For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-8 Table 6-2 Uncertainties Applied in the TM/LP Verification For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-9 Table 6-3 Transient Biases Applied in the TM/LP LSSS Verifications For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-10 Table 6-4 Transient Biases Applied in the TM/LP and LPD LSSS Verifications

[

]

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-11 Table 6-5 Additional Trip Setpoints (those used in Setpoints Verification)

Parameter Setpoint Variable high power 107.0%

Low reactor coolant flow 92%

High pressurizer pressure 2400 psia For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-12 Table 6-6 General Uncertainties Applied in the LCO Calculations For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-13 Table 6-7 Uncertainties Applied in DNB LCO LOCF Calculations For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-14 Table 6-8 Power Measurement Uncertainty

[

]

For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-15 Figure 6-1 LPD LSSS COLR Barn For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-16 Figure 6-2 Verification of LPD LSSS For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-17 (a)

(b)

Figure 6-3 TM/LP Trip Function A1: a) COLR, b) analysis For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-18 Figure 6-4 TM/LP Trip Function QR1 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-19 Figure 6-5 DNB LCO COLR Barn For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-20 Figure 6-6 Verification of DNB LCO for the Loss of Forced Reactor Coolant Flow Transient For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-21 Figure 6-7 LPD LCO COLR Barn (updated for CEA swapped condition)

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 6-22 Figure 6-8 Verification of LPD LCO For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 7-1 7.0

SUMMARY

OF ANALYSES PERFORMED The results of analyses performed to support the CEA Rod Swap Redesign are summarized below.

The MDNBR values presented in Table 7-1 account for the penalty multiplier developed for DNBR calculations. 1RWHWKDWWKHUHDUHWZRYDOXHVVKRZQIRUWKH)&0UHVXOWVWKHILUVWLVWKHF\FOH-specific analytical result, while the second is the limit.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 7-2 Table 7-1 Determination of Thermal-Hydraulic Analyses-of-Record For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 7-3 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 7-4 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 7-5 For Information Only

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 8-1 8.0 CODES A summary of the codes used to support this Safety Analysis Report, and Start-Up and Operation analyses, has been included in Table 8-1 below. The version of each code and status of adherence to the NRC approved methodology has been included. These codes have been maintained according to Framatome Inc. Quality Assurance procedures. The codes remain in compliance with the NRC-approved Framatome Inc. methodology and do not require NRC review.

Table 8-1 Codes used to support the Safety Analysis Report Code Version Status PRISM UJUN18 CAH3054 (CASMO-3)

UAPR16 MIH3016 (MICBURN-3)

UMAR05 XCOBRA-IIIC UNOV19 RODEX2-2A UJUN16 Note 3 S-RELAP5 UAPR23 Note 1, Note 2 SHAPEPWR UJUN15 RODEX3A UJUN10 Note 1: Most recent code version used for non-LOCA analyses. Previous versions have been used for older non-LOCA analyses and remain appropriate.

Note 2:

Versions UAPR09 and UOCT17 were used for the LOCA analyses in References 7, 8, and 9.

Note 3:

Version UFEB05 was used for the LOCA analysis in References 9.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 9-1

9.0 REFERENCES

1. NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, June 1987.
2. EMF-96-029(P)(A), Volumes 1 and 2, Reactor Analysis System for PWRs, Volume 1 -

Methodology Description, Volume 2 - Benchmarking Results, Siemens Power Corporation, January 1997.

3. EMF-2310(P)(A) Revision 1, SRP Chapter 15 Non-LOCA Methodology for Pressurized Water Reactors, Framatome ANP, May 2004.
4. EMF-92-153(P)(A), Revision 1, HTP: Departure From Nucleate Boiling Correlation for High Thermal Performance Fuel, Siemens Power Corporation, January 2005.
5. EMF-2103(P)(A) Revision 0, Realistic Large Break LOCA Methodology, April 2003.
6. EMF-2328(P)(A) Revision 0, PWR Small Break LOCA Evaluation Model, S-RELAP5 Based, March 2001.
7. ANP-3043(P) Revision 001, Calvert Cliffs RLBLOCA Summary Report, December 2011.
8. ANP-3043Q1(P) Revision 001, Calvert Cliffs RLBLOCA Summary Report, July 2012.
9. ANP-3641(P) Revision 000, Calvert Cliffs Units 1 and 2 Small Break LOCA (with EMF-2328 Supplement 1), March 2018.
10. EMF-1961(P)(A) Revision 0, Statistical Setpoint/Transient Methodology for Combustion Engineering Type Reactors, Siemens Power Corporation, July 2000.
11. XN-NF-75-21(P)(A), Revision 2, XCOBRA-IIIC: A Computer Code to Determine the Distribution of Coolant During Steady-State and Transient Core Operation, Exxon Nuclear Company, Inc., January 1986.
12. XN-75-32(P)(A), Supplements 1 through 4, Computational Procedure for Evaluating Fuel Rod Bowing, Exxon Nuclear Company, October 1983. (Base document not approved)
13. XN-NF-78-44(NP)(A), A Generic Analysis of the Control Rod Ejection Transient for Pressurized Water Reactors, Exxon Nuclear Company, Inc., October 1983.

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ANP-4173NP Revision 0 Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report Page 9-2

14. XN-NF-82-21(P)(A), Revision 1, Application of Exxon Nuclear Company PWR Thermal Margin Methodology to Mixed Core Configurations, Exxon Nuclear Company, September 1983.
15. Safety Evaluation Report - Transition to AREVA NP Fuel and Safety Analysis Methodology, Calvert Cliffs Nuclear Power Plant, Docket Nos. 50-317 and 50-318, NRC Accession number of ML110390224. (This report is a public record and retrievable from the NRC Public Library.)
16. Letter, Constellation to Scott McLaughlin (Framatome Inc.), Constellation Transmittal of Design Information (NF240329), Revision 1, Transmittal of Plant Parameters Unit 2 Cycle 26 Safety Analysis, July 2024
17. ANP-3228(P) Revision 4, Calvert Cliffs Inputs to PSV Setpoint Uncertainty License Amendment Request, March 2014.
18. EMF-2328(P)(A) Revision 0, Supplement 1(P)(A), Revision 0, PWR Small Break LOCA Evaluation Model, S-RELAP5 Based, December 2016.
19. Code of Federal Regulations, Title 10, Part 50, Section 46, Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Nuclear Power Reactors, August 2007.
20. EMF-2310, Revision 1, Supplement 2P-A, Revision 0, SRP Chapter 15 Non-LOCA Methodology for Pressurized Water Reactors, Framatome Inc, March 2023.

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contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachment 6, this document is decontrolled.

ATTACHMENT 6 Emergency License Amendment Request Calvert Cliffs Nuclear Power Plant, Unit 2 Renewed Facility Operating License No. DPR-69 NRC Docket No. 50-318 Framatome Report ANP-4173P Rev. 0, Calvert Cliffs Unit 2 Cycle 26 CEA Rod Swap Redesign Safety Analysis Report (Proprietary)