Text

License Amendment Request Regarding Ultimate Heat Sink
	ML091831253
Person / Time
Site:	Byron
Issue date:	06/30/2009
From:	Simpson P R; Exelon Generation Co, Exelon Nuclear
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	RS-09-054
	Download: ML091831253 (238)
	v • d • e

Exelon Nuclear www.exeloncorp.co m 4300 Winfiield Road War renville, I L 60555 RS-09-054 10 CFR 50.90 June 30, 2009 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

License Amendment Regarding Ultimate Heat Sink References

1. Letter from Ann Marie Stone (NRC) to Charles G. Pardee (Exelon Generation Company, LLC), "Byron Station, Units 1 and 2 Follow Up Inspection of an Unresolved Item (URI) 05000454/2008008

0500045512008008," dated May 5, 2008 Exelon 2. Letter from David M. Hoots (Exelon Generation Company, LLC) to NRC, "Response to NRC Request Concerning Unresolved Item 05000454/2008008 and 05000455/2008008," dated June 4, 2008 Nuclear 3. Letter from Daniel J. Enright (Exelon Generation Company, LLC) to NRC, "Updated Information to Response to NRC Request Concerning Unresolved Item 05000454/2008008 and 05000455/2008008," dated March 5, 2009 In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (EGC) is requesting changes to the Technical Specifications (TS) of Facility Operating License Nos. NPF-37 and NPF-66 for Byron Station, Unit 1 and Unit 2. Specifically, the proposed change will revise TS 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect results of a revised analysis for the UHS. In Reference 1, the NRC requested a response describing EGC's intended actions and proposed schedule to resolve the noncompliance of single failure assumptions used in the Byron Station UHS design basis analysis. Reference 2 provided a summary of EGC's intended actions and proposed schedule to resolve the noncompliance. The intended action was to perform a revised analysis of the UHS to evaluate the impact of postulated passive electrical single failures. The results of this analysis would then be incorporated into the Byron Station design and licensing bases in accordance with 10 CFR 50.59, "Changes, tests, and experiments

." This was expected to be completed by December 5, 2008.

June 30, 2009 U. S. Nuclear Regulatory Commission Page 2 However, in Reference 3, EGC provided an update to the intended actions since it was determined that the results of the revised analysis could not be incorporated into the Byron Station design and licensing bases in accordance with 10 CFR 50.59 without prior NRC approval. Specifically, Reference 3 stated that a license amendment request would be submitted to the NRC by the end of the second quarter 2009. This request is subdivided as follows: " Attachment 1 provides an evaluation supporting the proposed change. " Attachment 2 provides the marked-up TS pages with the proposed changes indicated. " Attachment 3 provides the marked-up TS Bases pages with the proposed changes indicated. The TS Bases pages are provided for information only, and do not require NRC approval. " Attachment 4 provides the analytical basis for the proposed changes to the TS cooling tower basin temperature limits. " Attachment 5 provides validation of Assumption 3.1 from Attachment

4. " Attachment 6 provides simplified drawings of scenarios 8A, 8B and 8D1, 8C and 8D, 8C1, and 8C2 as described in Attachment

4. " Attachment 7 provides an evaluation of additional scenarios for breaker failure during cool weather when the SXCT bypass valves could be open " Attachment 8 provides simplified drawings of scenarios 10, 11, 12, and 13 as described in Attachment

7. " Attachment 9 provides a listing of regulatory commitments made in this submittal. To compensate for the nonconforming condition, the EGC has implemented administrative controls to allow only one fan out of service, compared to two allowed by TS. Additionally, bounding SX pump discharge temperature limits based on the results of the revised analysis have been put in place. These administrative controls invoke the provisions of NRC Administrative Letter (AL) 98-10, "Dispositioning of Technical Specifications That Are Insufficient to Assure Plant Safety," and will remain in place until the NRC dispositions the proposed TS changes. EGC requests approval of the proposed change by June 30, 2010. Once approved, the amendment will be implemented within 90 days. This implementation period will provide adequate time for the affected station documents to be revised using the appropriate change control mechanisms. The proposed amendment has been reviewed by the Byron Station Plant Operations Review Committee and approved by the Nuclear Safety Review Board in accordance with the requirements of the EGC Quality Assurance Program. In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b), EGC is notifying the State of Illinois of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

June 30, 2009 U. S. Nuclear Regulatory Commission Page 3 Regulatory commitments are contained in Attachment

9. Should you have any questions concerning this letter, please contact Mr. Kenneth M. Nicely at (630) 657-2803. I declare under penalty of perjury that the foregoing is true and correct. Executed on the 30th day of June 2009. Respectfully, P6 Patrick R. Simpson Manager - Licensing Attachments

1. Evaluation of Proposed Change 2. Markup of Proposed Technical Specifications Pages 3. Markup of Proposed Technical Specifications Bases Pages 4. Analytical Basis for the Proposed Changes to the Cooling Tower Basin Temperature Limits 5. Information Supporting Validation of Assumption 3.1 6. Simplified Drawings of Scenarios 8A, 813 and 8D1, 8C and 8D, 8C1, and 8C2 7. Evaluation of Additional Scenarios for Breaker Failure During Cool Weather When the SXCT Bypass Valves Could Be Open 8. Simplified Drawings of Scenarios 10, 11, 12, and 13 9. Summary of Regulatory Commitments ATTACHMENT 1 Evaluation of Proposed Change 1.0

SUMMARY

DESCRIPTION

2.0 DETAILED

DESCRIPTION

3.0 TECHNICAL

EVALUATION

4.0 REGULATORY EVALUATION

4.1 Applicable

Regulatory Requirements/Criteria

4.2 Precedent

4.3 No Significant Hazards Consideration

4.4 Conclusion

5.0 ENVIRONMENTAL

CONSIDERATION

6.0 REFERENCES

Page 1 of 11 1.0

SUMMARY

DESCRIPTION ATTACHMENT 1 Evaluation of Proposed Change In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (EGC) is requesting changes to the Technical Specifications (TS) of Facility Operating License Nos. NPF-37 and NPF-66 for Byron Station, Unit 1 and Unit 2. Specifically, the proposed change will revise TS 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect results of a revised analysis for the UHS. 2.0 DETAILED DESCRIPTION The proposed changes are as follows. A markup of the proposed TS changes is provided in Attachment

2. TS 3.7.9 "ACTIONS" " A new Condition A is added to address the requirement, dependent on the SX pump discharge temperature, that required operable cooling tower fans must be operating in high speed. If the required number of cooling tower fans are not running in high speed, then the Required Action is to initiate actions immediately to operate the fan in high speed. " Current Condition A has been moved to become new Condition B due to the new Condition A having a shorter Completion Time. " A new Condition C is added to address the outside air wet bulb temperature restriction when only six cooling tower fans are operable and the two inoperable cooling tower fans are powered by the same electrical division. The Required Action is to restore the cooling tower fan configuration such that two inoperable cooling tower fans are not powered by the same electrical division. The Completion Time is 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . " A new Condition D is added to address the condition of exceeding the maximum allowed SX pump discharge temperature of 96°F. In this condition, the required actions are to bring the Unit(s) to MODE 3 in six hours and MODE 5 in 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . " Current Conditions A through G and their associated Required Actions steps are re-lettered to account for the added new Conditions A, B, C and D. Current Condition G is revised to reflect the new Actions and the re-lettering. " The Completion Time for current Conditions C, D, E, and F (new Conditions F,G, H and I) are revised to add "Once per" to the periodic monitoring requirements to make the wording consistent with Improved Technical Specifications standard wording for periodic monitoring required by an Action Condition. There is no change of intent for this revision. Page 2 of 11 TS 3.7.9-"SURVEILANCE REQUIREMENTS" ATTACHMENT 1 Evaluation of Proposed Change " Surveillance Requirement (SR) 3.7.9.2 is revised to implement the additional cooling tower fan requirements resulting from the revised analysis of the UHS. The new SR verifies that there are six required cooling tower fans when SX pump discharge temperature is less than or equal to 77°F. The SR is modified by a note. This Note stipulates that if SX pump discharge temperature is greater than 77°F, then the additional cooling tower fan requirements of Table 3.7.9-1 shall be met. " Table 3.7.9-1 contains the additional cooling tower fan requirements when SX pump discharge temperature is greater than 77°F. These additional requirements include the number of required operable cooling tower fans and whether they need to be running in high speed. " A new SR 3.7.9.10 has been added to verify outside air wet bulb temperature is less than or equal to 76°F when two inoperable cooling tower fans are powered by the same electrical division. The SR number is intentionally not placed in the Improved Technical Specifications numbering convention of shortest to longest frequencies due to human error considerations associated with re-numbering all SRs in TS 3.7.9. As described in Reference 1, a concern was identified by the NRC with respect to the single failure assumptions taken in the Byron UHS analysis. The specific concern was the Byron UHS analysis only considered single active breaker or switch failures that resulted in the failure of one essential service water cooling tower (SXCT) fan. Passive failures of the 4160 volt or 480 volt feed breakers which could de-energize the bus and result in the loss of two SXCT fans were not considered. Consistent with the definition of a single failure presented in 10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants" and General Design Criteria (GDC) 44, "Cooling Water," the spurious failure (i.e., opening) of 4160 volt or 480 volt feed breakers for the SXCT fans should have been considered a valid failure and should have been assessed accordingly. In Reference 1, the NRC requested a response describing EGC's intended actions and a proposed schedule to resolve the noncompliance of single failure assumptions used in the Byron Station UHS design basis analysis. In Reference 2, Byron Station provided a response to Reference 1 with intended actions and a proposed schedule. The intended action was to perform a revised analysis of the UHS to evaluate the impact of postulated passive electrical single failures. The results of this analysis would then be incorporated into the Byron Station design basis via requirements of 10 CFR 50.59, "Changes, tests, and experiments

." This was expected to be completed by December 5, 2008. In Reference 3, Byron Station provided an update to the intended actions outlined in Reference

2. EGC determined that the results of the revised analysis could not be incorporated into the Byron Station design basis via requirements of 10 CFR 50.59, "Changes, tests, and experiments

." Reference 3 states that due to delays in finalizing the re-analysis, the updated intended action is to submit a license amendment request (LAR) to the NRC by the end of the second quarter 2009. Page 3 of 11 ATTACHMENT 1 Evaluation of Proposed Change To compensate for the nonconforming condition, the EGC has implemented administrative controls to allow only one fan out of service, compared to two allowed by TS. Additionally, bounding SX pump discharge temperature limits based on the results of the revised analysis have been put in place. These administrative controls invoke the provisions of NRC Administrative Letter (AL) 98-10, "Dispositioning of Technical Specifications That Are Insufficient to Assure Plant Safety," and will remain in place until the NRC dispositions the proposed TS changes. 3.0 TECHNICAL EVALUATION Backqround The UHS provides a heat sink for processing and operating heat from safety related components during a transient or accident, as well as during normal operation. This is done by utilizing the SX system and the Component Cooling Water (CC) system. In addition, the UHS is the safety related source of Auxiliary Feedwater (AF) in case the Condensate Storage Tank is unavailable. The UHS is the sink for heat removed from the reactor core following all accidents and anticipated operational occurrences in which the unit is cooled down and placed on Residual Heat Removal (RHR) operation, as well as the sink for heat removed from containment via the reactor containment fan coolers. The UHS is a common system and consists of two, four-cell, mechanical draft cooling towers, OA and OB, and a makeup system. Each tower has four manually actuated fans. Each fan can be run in either high or low speed. Two of the Tower OA fans are powered from Unit 1, Division 11 and the other two fans are powered from Unit 2, Division 21. Similarly, two Tower OB fans are powered from Unit 1, Division 12 and the other two fans are powered from Unit 2, Division 22. Design Analyses As described in Reference 1, a concern was identified by the NRC with respect to the single failure assumptions taken in the Byron UHS analysis. The specific concern was the Byron UHS analysis only considered single active breaker or switch failures that resulted in the failure of one essential service water cooling tower (SXCT) fan. Passive failures of the 4160 volt or 480 volt feed breakers, which could de-energize the bus and result in the loss of two SXCT fans, were not considered. Consistent with the definition of a single failure presented in 10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants," and General Design Criteria (GDC) 44, "Cooling Water," the spurious failure (i.e., opening) of 4160 volt or 480 volt feed breakers for the SXCT fans should have been considered a valid failure and should have been assessed accordingly. To address this single failure assumption concern, additional time dependent basin temperature calculations were performed to evaluate the postulated passive breaker failures. The calculations were performed using the methodology described in UFSAR Section 9.2.5.3.1.1.3, "Time Dependent Basin Temperature Calculations

." Page 4 of 11 ATTACHMENT I Evaluation of Proposed Change 1. These calculations predicted the basin temperature using a time dependent two cooling tower model. 2. The time dependent feature of the model was developed to account for the transient nature of the loss-of-coolant accident (LOCA) heat load. The calculations used the time dependent total heat loads to determine the amount of heat added to the essential service water system. 3. The two cooling tower model was developed to provide the capability to analyze different flow and energy (i.e., heat load) going to each of the cooling towers. The flow to each of the cooling towers could be significantly different under different accident scenarios. Depending on the scenario, the modeling of energy transport also considered the distribution of miscellaneous heat loads. Cooling was assumed to occur only for cells with fans running at high speed. UFSAR Section 9.2.5.3.1.1.1, "Containment Heat Load Calculations," and UFSAR Section 9.2.5.3.1.1.2, "Steady State Tower Performance Analysis," describe the containment heat load calculations and the steady state tower performance analysis used as input to the time dependent basin temperature calculations. As described in UFSAR Section 2.3.1.2.4, "Ultimate Heat Sink Design," per Reference 4, Regulatory Guide 1.27, Revision 2, "Ultimate Heat Sink for Nuclear Power Plants," the UHS must be capable of performing its cooling function during the design basis event for the worst-case three-hour air wet bulb temperature. The UHS time dependent temperature analysis was conducted with the highest three-hour air wet bulb temperature of 82°F. The following input changes were made in the calculations to evaluate postulated passive breaker failures: New scenarios were developed for postulated breaker failures with zero, one, and two SXCT fans assumed to be inoperable. " The previous analysis assumed that for an active fan failure, operator action would be taken to isolate the associated riser valve to optimize heat removal in the cooling tower. Cooling was previously assumed to occur only for the cells with fans running at high speed. Postulated breaker failures would also result in the loss of power to the motor operated riser valves for the impacted SXCT fan. If the riser valve for the affected fan was open prior to the postulated breaker failure, operator actions to isolate the riser valves and redistribute SX return water to active cooling tower cells cannot be taken from the control room. For the revised analysis, the fraction of water cooled for SX cooling tower cells with fans not running is assumed to be 0.10 (i.e., 10% of the water delivered to that cell is effectively cooled). This is based on input from the cooling tower manufacturer of minimum cooling tower performance without fan airflow. The SX flow model was used to calculate SX flow to the cooling tower cells for the new scenario alignments. Cooling tower cell flow is an input to the steady state tower performance analysis. Page 5 of 11 ATTACHMENT 1 Evaluation of Proposed Change The heat load on the UHS was recalculated to remove the heat load from the recycle evaporator that has been abandoned in place. In a LOCA event, under the most severe design basis weather conditions (i.e., maximum air wet bulb temperature), with a breaker failure that results in the loss of two SXCT fans, it is assumed that operators will shed heat load by securing up to two of the four reactor containment fan coolers on the LOCA unit within 30 minutes. As discussed in UFSAR Section 6.2.2, "Containment Heat Removal System," only one of the two reactor containment fan cooler trains is required for post-accident containment heat removal. This is a reasonable assumption because the required action can be taken from the control room. EGC will revise appropriate procedures, as part of the implementation activities for the proposed license amendment, to ensure procedural guidance is put in place to direct these actions. Initial SX basin temperatures were calculated based on maintaining the peak basin temperature less than the SX system design temperature of 100°F for all evaluated scenarios. The calculation results, assuming a postulated breaker failure that causes the loss of two SXCT fans, are summarized as follows: For the scenarios where two fans are initially out of service, it was determined that either the fans need to be powered by different buses or the outside air wet bulb temperature must be less than 76°F. This limitation is required because with two fans out of service on the same electrical division, a postulated breaker failure could result in two additional fans being lost on the same tower (i.e., no fans running on one tower and four fans running on the second tower) as outlined in scenario 8C1 of Attachment

6. In this configuration, with the worst-case three-hour air wet bulb temperature of 82°F, the initial basin temperature required to prevent the calculated peak basin temperature from exceeding the design SX system design temperature of 100°F was below the normal basin operating temperature. Thus, the proposed Technical Specification requires that when only six cooling tower fans are operable and the two inoperable cooling tower fans are powered by the same electrical division, the outside air wet bulb temperature must be less than 76°F. Attachment 4 includes the analytical basis for the proposed change. Specifically, Attachment 4 provides the portion of calculation NED-M-MSD-009, "Byron Ultimate Heat Sink Cooling Tower Basin Temperature Calculation

Part IV," Revision 8, that evaluates the breaker failure. Attachment 5 includes validation of Assumption 3.1 from Attachment 4 (i.e., the assumption that 10% of the water is cooled for SX cooling tower cells with fans not running). Attachment 6 Page 6 of 11 Cells Initially Out of Service Fans Initially Running Fans Running Initial Basin Maximum Basin " erature 2 0 4 77°F 99.7°F 2 6 4 84°F 99.9°F 1 0 5 82°F 99.7°F 1 7 5 91 °F 99.6°F __ 0 8 _ 6 96°F 98.6°F ATTACHMENT 1 Evaluation of Proposed Change includes simplified drawings of scenarios 8A, 8B, 8D1, SC, 8D, 8C1, and 8C2 as described in Attachment

4. The cool weather UHS basin temperature analysis was also revised. During cool weather, the SXCT bypass valves could be open. Postulated breaker failures could result in the power loss of two SXCT fans, the two SX riser valves for the cells associated with the lost SX fans, and the power loss of one SX basin bypass valve for the SXCT that has the lost SX fans and associated riser valves. The analysis showed that maximum basin water temperature remained below 100°F for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCA and a loss of offsite power on one unit, with the opposite unit in normal shutdown. Attachment 7 includes the portion of calculation NED-M-MSD-011, "Byron Ultimate Heat Sink Cooling Tower Basin Temperature Calculation

Part V (Bypass Operation)," Revision 3, that evaluates the breaker failure during cool weather when the SXCT bypass valves could be open. Attachment 8 includes simplified drawings of scenarios 10, 11, 12, and 13 as described in Attachment

7. Several of the assumptions used in the analyses were inherently conservative. These conservatisms, while not quantitatively analyzed, provide additional margin to the 100°F SX system design temperature. Some of the major conservatisms are listed below. " As described in UFSAR Section 9.2.5.3.1.1.1, "Containment Heat Load Calculations," the heat input to the UHS is conservatively based on assuming higher SX flow rates to the reactor containment fan coolers, assuming higher air flow rates to the reactor containment fan coolers, and assuming earlier switchover to containment recirculation phase and corresponding earlier RHR heat loads. Additionally, the calculated maximum heat input from the reactor containment fan coolers was conservatively based on an assumed SX supply temperature of 32°F. This value is conservative compared to the calculated peak UHS temperatures. " Basin level in the analysis is based on less than the TS minimum level of 60%. SX basin level is normally maintained higher than the TS minimum, which would provide additional water inventory heat capacity. To ensure that the actual UHS temperature does not exceed the TS surveillance limit, the surveillance procedure used to demonstrate compliance with the TS surveillance limit will be revised to accommodate instrument uncertainty.

4.0 REGULATORY EVALUATION

4.1 Applicable

Regulatory Requirements/Criteria The NRC Standard Review Plan (SRP) Section 9.2.5, "Ultimate Heat Sink," in Reference 5, applies to the design of the UHS. The acceptability of the design of the UHS is based on Reference 4, Regulatory Guide 1.27, Revision 2, "Ultimate Heat Sink for Nuclear Power Plants," and the following GDC of 10 CFR 50, Appendix A: Page 7 of 11 ATTACHMENT 1 Evaluation of Proposed Change GDC 2 - Design bases for protection against natural phenomena; GDC 4 - Environmental and dynamic effects design basis; GDC 5 - Sharing of structures, system, and components

GDC 17 - Electric power systems; GDC 38 - Containment heat removal; GDC 44 - Cooling water; GDC 45 - Inspection of cooling water system; and GDC 46 - Testing of cooling water system. EGC has reviewed the basis for conformance to these GDC, as described in the Byron Station UFSAR, and has concluded that the proposed change remains in conformance with all requirements. The proposed change addresses possible breaker failures to meet the requirements of GDC 44, including the requirement to ensure the system safety function can be accomplished assuming a single failure. The guidance provided in Regulatory Guide 1.27, Revision 2, was employed for the temperature analysis of the Byron UHS. The UHS, with the proposed changes, will continue to meet the applicable acceptance criteria of SRP Section 9.2.5 and Regulatory Guide 1.27. Based on the above, it is concluded that the UHS will continue to meet the requirements of GDC 2, 4, 5, 17, 38, 44, 45, and 46 and is, therefore, acceptable with the proposed change. 4.2 Precedent The NRC previously approved a similar amendment for Vogtle Electric Generating Plant. In a letter dated December 2, 2005, Reference 6, the NRC approved a license amendment request that added temperature-graded nuclear service cooling water fan operability requirements to TS 3.7.9, "Ultimate Heat Sink," since the TS only required the UHS system to be operable. Similar to the EGC proposed change to include the consideration of the spurious failure and/or opening of the 4160 volt or 480 volt, the Vogtle addition of nuclear service cooling water fan operability requirements to TS was considered to be a change to nonconservative UHS TS requirements. 4.3 No Significant Hazards Consideration In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (EGC) is requesting changes to the Technical Specifications (TS) of Facility Operating License Nos. NPF-37 and NPF-66 for Byron Station, Unit 1 and Unit 2. Specifically, the proposed change will revise TS 3.7.9, "Ultimate Heat Sink (UHS)," to add additional essential service water (SX) cooling tower fan requirements as a function of SX pump discharge temperature to reflect results of a revised analysis for the UHS. According to 10 CFR 50.92, "Issuance of amendment," paragraph (c), a proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: Page 8 of 11 Involve a significant increase in the probability or consequences of any accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or ATTACHMENT 1 Evaluation of Proposed Change Involve a significant reduction in a margin of safety. EGC has evaluated the proposed change, using the criteria in 10 CFR 50.92, and has determined that the proposed change does not involve a significant hazards consideration. The following information is provided to support a finding of no significant hazards consideration. 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed change does not result in any physical changes to safety related structures, systems, or components. The UHS itself is not an accident initiator; rather, the UHS performs functions to mitigate accidents by serving as the heat sink for safety related equipment. Consequently, the proposed change does not increase the probability of occurrence for any accident previously evaluated. The UHS plays a vital role in mitigating the consequences of any accident or transient. The proposed changes will ensure that the minimum conditions necessary for the UHS to perform its design functions will always be met. Engineering calculations demonstrate that the SX pump discharge design temperature limit of 100°F, which was assumed as an initial input for the accident analyses, is preserved. Consequently, the proposed changes to cooling tower fan requirements, relative to the SX pump discharge temperature, do not increase the consequences of any accident previously evaluated. 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 supporting analyses for the proposed change do not involve a new or different kind of accident from any accident previously evaluated. The proposed limits on maximum SX pump discharge temperature, and the proposed fan requirements, are within the design capabilities of the UHS and ensure that the UHS will always be in a condition to perform its design function in the event of an accident or transient. New and revised analyses that support the requested TS changes ensure the full qualification of the UHS. No changes are being made to Page 9 of 11

3. Does the proposed change involve a significant reduction in a margin of safety? Response: No ATTACHMENT 1 Evaluation of Proposed Change the physical design of the UHS such that the possibility of a new or different kind of accident would be created. Consequently, these changes do not create the possibility of a new or different kind of accident from those previously evaluated. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated. The proposed limits on SX pump discharge maximum temperature are based on the results of new and revised design analyses that ensure that the margin of safety is not reduced. The new limits on temperature will ensure that, under the most limiting accident or transient scenario, cooling water will meet the accident analyses SX design temperature limit of 100°F. Therefore, the proposed change does not involve a significant reduction in a margin of safety. Based on the above evaluation, EGC has concluded that the proposed amendment presents no significant hazards considerations under the standards set forth in 10 CFR 50.92(c). 4.4 Conclusion In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. 5.0 ENVIRONMENTAL CONSIDERATION EGC 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 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. Page 1 0 of 11

6.0 REFERENCES

ATTACHMENT 1 Evaluation of Proposed Change 1. Letter from Ann Marie Stone (NRC) to Charles G. Pardee (Exelon Generation Company, LLC), "Byron Station, Units 1 and 2 Follow Up Inspection of an Unresolved Item (URI) 05000454/2008008

05000455/2008008," dated May 5, 2008 2. Letter from David M. Hoots (Exelon Generation Company, LLC) to NRC, "Response to NRC Request Concerning Unresolved Item 05000454/2008008 and 05000455/2008008," dated June 4, 2008 3. Letter from Daniel J. Enright (Exelon Generation Company, LLC) to NRC, "Updated Information to Response to NRC Request Concerning Unresolved Item 05000454/2008008 and 05000455/2008008," dated March 5, 2009 4. NRC Regulatory Guide 1.27, Revision 2, "Ultimate Heat Sink for Nuclear Power Plants," dated January 1976 5. NRC Standard Review Plan Section 9.2.5, "Ultimate Heat Sink," Revision 2, NUREG-800, dated July 1981 6. Letter from Mr. Christopher Gratton (NRC) to Mr. D. E. Grissette (Southern Nuclear Operating Company), "Vogtle Electric Generating Plant, Units 1 and 2, Issuance of Amendments Regarding Ultimate Heat Sink (TAC Nos. MC2762 and MC2763)," dated December 2, 2005 Page 11 of 11 ATTACHMENT 2 Markup of Proposed Technical Specifications Pages Byron Station Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 REVISED TECHNICAL SPECIFICATIONS PAGES 3.7.9-1 through 3.7.9-6

3.7 PLANT

SYSTEMS 3.7.9 Ultimate Heat Sink (UHS) LCO 3.7.9 The UHS shall be OPERABLE. APPLICABILITY

MODES l, 2, 3, and 4. ACTIONS Restore both basin levels to >_ 60%. -9. One or more basin level (s) < 609. Replace with INSERT 3.7.9-1 UHS 3.7.9 (continued)

BYRON - UNITS 1 & 2 3.7.9 - 1 Amendment 106 INSERT 3.7.9-1 A. ------------NOTE--------------

A.1 Initiate actions to operate Immediately Only applicable when required OPERABLE additional cooling tower cooling tower fans in high fans requirements of speed. Table 3.7.9-1 require OPERABLE cooling tower fans to be running in high speed. ------------------------------

One or more required cooling tower fans not running in high speed. B. One required cooling tower B.1 Verify remaining required 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months fan inoperable. OPERABLE cooling tower fans are capable of being powered by an OPERABLE emergency power source. AND B.2 Restore required cooling 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months tower fans to OPERABLE status. C. Two inoperable cooling C.1 Restore cooling tower fan 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months tower fans that are configuration such that powered by the same two inoperable cooling electrical division. tower fans are not powered by the same AND electrical division. Outside air wet bulb temperature

> 76°F. D. Essential Service Water D.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months (SX) pump discharge temperature

> 96°F. AND D.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months ACTIONS (continued)

CONDITION One Essential Service Water (SX) makeup pump inoperable. F AND AND 1~r REQUIRED ACTION Verify basin level for each tower is >_ 90%. Restore SX makeup pump to OPERABLE status. COMPLETION TIME 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months AND 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months thereafter Verify OPERABILITY of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months associated makeup source. 14 days if one unit is in MODE 5, 6 or defuel ed UHS 3.7.9 7 days if both units are in MODE 1, 2, 3, or 4 AND (continued)

BYRON - UNITS 1 & 2 3.7.9 - 2 Amendment 141 ACTIONS (continued)

~). Two SX m a inoperab CONDITION

¬. Rock River water level ~ 670.6 ft Mean Sea Level (MSL). Verify OPERABILITY of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months at least one makeup source. REQUIRED ACTION Verify basin level for each tower is 90%. Once per 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months AND 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months ."~ thereafter Verify OPERABILITY of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months second makeup source. Verify Rock River water level is > 664.7 ft MSL and flow >_ 700 cubic feet per second (cfs). Once per COMPLETION TIME 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months AND 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter UHS 3.7.9 (continued)

BYRON - UNITS 1 & 2 3.7.9 - 3 Amendment 141 keup pumps e. D-4 .1 AND 8-2 G.2 AND B:3 .3 f: 1 ACTIONS (continued)

REQUIRED ACTION F, 4 Verify basin level for each tower is >_ 90%. Verify OPERABILITY of at least one deep well pump. ~3 Verify OPERABILITY of both deep well pumps. 6:4 Be in MODE 3. Be in MODE 5. OR CONDITION

¬. Required Action ,-9 not met. Rock River water level forecast to exceed 702.0 ft MSL by the National Weather Service (NWS). OR Tornado Watch issued by the NWS that includes the Byron site. Required Action and associated Completion Time of Condition 9, B, e c-; not met. OR UHS inoperable for reasons other than Condition A, 9, COMPLETION TIME 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months AND -y---- Once per 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months thereafter 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 72 hours 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 36 hours UHS 3.7.9 BYRON - UNITS 1 & 2 3.7.9 - 4 Amendment 141 SURVEILLANCE REQUIREMENTS

_----------

_NOTE ---------

_-------------

If SX pump discharge temperature is > 77°F then the additional cooling tower fan requirements in Table 3.7.9-1 shall be met. Verify six required OPERABLE cooling tower fans and SX pump discharge temperature

< 77°F. UHS 3.7.9 (continued)

BYRON - UNITS 1 & 2 3.7.9 - 5 Amendment 106 SURVEILLANCE FREQUENCY SR 3.7.9.1 Verify water level in each cooling tower 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months basin is >_ 60%. SR 3.7.9.2 Ve r 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Qnor. I J .. J SR 3.7.9.3 Verify river water level is > 670.6 ft MSL 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and _ 702.0 ft MSL. SR 3.7.9.4 Operate each required cooling tower fan on 31 days high speed for >_ 15 minutes. SR 3.7.9.5 Verify each SX makeup manual, power 31 days operated, and automatic valve in the flow path that is not locked, sealed, or otherwise secured in the open position, is in the correct position. SR 3.7.9.6 Verify that each SX makeup pump starts on a 31 days simulated or actual low basin level signal and operates for >_ 30 minutes.

SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.9.10 ----------

NOTE -----------

__-Only required when two inoperable cooling tower fans are powered by the same electrical division. Verify outside air wet bulb 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months temperature is < 76°F. Add INSERT 3.7.9-2 as a new page UHS 3.7.9 BYRON - UNITS 1 & 2 3.7.9 - 6 Amendment 106 SURVEILLANCE FREQUENCY SR 3.7.9.7 Verify each diesel driven SX makeup pump 31 days fuel oil day tank level >_ 47%. SR 3.7.9.8 Cycle each testable valve in the SX makeup 18 months pump flow path through at least one complete cycle of full travel. SR 3.7.9.9 Verify fuel oil properties are tested in In accordance accordance with and maintained within the with the Diesel limits of the Diesel Fuel Oil Testing Fuel Oil Program. Testing Program INSERT 3.7.9-2 Table 3.7.9-1 (page 1 of 1) Additional Cooling Tower Fan Requirements (a) When in Condition B, the number of OPERABLE cooling tower fans running in high speed is one less than indicated. SX PUMP DISCHARGE ADDITIONAL TEMPERATURE REGION REQUIREMENTS

> 77°F and < 82°F Either 6 required OPERABLE cooling tower fans running in high speed, or 7 cooling tower fans are required to be OPERABLE > 82°F and _< 84°F 6 required OPERABLE cooling tower fans running in high speed > 84°F and < 91'F 7 required OPERABLE cooling tower fans running in high speed > 91 °F and _< 96°F 8 required OPERABLE cooling tower fans running in high speed ATTACHMENT 3 Markup of Proposed Technical Specifications Bases Pages Byron Station Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 REVISED TECHNICAL SPECIFICATIONS BASES PAGES B 3.7.9-1 through B 3.7.9-16 B 3.7 PLANT SYSTEMS B 3.7.9 Ultimate Heat Sink (UHS) BASES UHS B 3.

7.9 BACKGROUND

The UHS provides a heat sink for processing and operating heat from safety related components during a transient or accident, as well as during normal operation. This is done by utilizing the Essential Service Water (SX) System and the Component Cooling Water (CC) System. In addition, the UHS is the safety related source of Auxiliary Feedwater (AF) in case the Condensate Storage Tank is unavailable. The UHS is a common system and consists of two, four cell, mechanical draft cooling towers (OA and OB) and a makeup system. Each tower has four fans (with two speeds - high and low), which are manually actuated. Two of the Tower OA fans are powered from Unit 1, Division 11 and two fans are powered from Unit 2, Division 21. Similarly two Tower OB fans are powered from Unit 1, Division 12 and two fans are powered from Unit 2, Division 22. The normal makeup to the towers is provided by the non-safety related, non-engineered safety feature, Circulating Water System. Two safety related diesel-driven makeup pumps, which take suction from the Rock River, provide makeup to each of the towers (one pump per tower). Level switches are provided to automatically start the pump on low level in the associated tower basin. In addition, a deep well pump, powered from the engineered safety feature bus associated with each tower is capable of providing makeup to either basin. The deep well pumps do not include automatic start capability. The two tower basins communicate at approximately the 64% basin level. Each makeup source is capable of supplying sufficient makeup water to maintain adequate basin inventory. Makeup is required to compensate for AF supply, as well as drift, evaporation and blowdown losses, resulting from design basis Loss Of Coolant Accident (LOCA) conditions in one unit concurrent with the safe shutdown of the other unit. BYRON - UNITS 1 & 2 B 3.7.9 - 1 Revision 0 BASES BACKGROUND (continued)

UHS B 3.7.9 Additional information on the design and operation of the system, along with a list of components served, can be found in UFSAR, Section 9.2.5 (Ref. 1). APPLICABLE The UHS is the sink for heat removed from the reactor core SAFETY ANALYSES following all accidents and anticipated operational occurrences in which the unit is cooled down and placed on Residual Heat Removal (RHR) operation as well as the sink for heat removed from containment via the reactor containment fan coolers. The UHS performance requirements are that the design basis temperatures of safety related equipment served by SX, either directly or indirectly are not exceeded. The UHS maximum post accident heat load occurs near the time the unit switches from injection to recirculation and the containment cooling systems and residual heat removal systems are required to remove core decay heat. The status of both units must be considered in the UHS analyses, because the UHS is a common system. The design basis accident analyses for the UHS is based on design basis LOCA/loss of offsite power conditions on one unit concurrent with the safe shutdown from maximum power of the other unit. References 2, 3, the UHS design basis analyses. The expected meteorological conditions, uncertainties when calculating dec e single failures. provide details of nalyses include worst conservative y heat, and worst case BYRON - UNITS 1 & 2 B 3.7.9 - 2 Revision 0 BASES APPLICABLE SAFETY ANALYSES (continued)

The UHS B 3.7.9 Replace with INSERT B 3.7.9-1 that with the 4RS PURRiH9 the ~X Y u . RM .. .. Mr. ZT.T. MT2D'm:n'.1WMM57y nmr" aTr~~~~>.a" r~n iT PT. ii Fir" Ill" 11011115a I Tlir" 1" ir \1 l1' " L" LFllr/"~Ta tem9nnaf-Hno of 96 o P -with - at lead- 6 fans Punninn nr l @Oog 'IT iiil" i~" 171i1" ii1 ;T.=" 6 iI 1-M'1Y" i~wws~~~W

=7M"%=M """" r" T"" ii 1a=11=14 =""" Ilii iri" Y":V MUM FLr 7" M=" Fl M, " F Mfi ii21T ii~7"lli"" T iv 7t~7="" i.\Mii" Nli" 1t~i=17" T~R1ii.=M%" T air ~nrau r~ci>" s 0 The analyses assume an initial basin level of _> 60% in both cooling tower basins, which corresponds to approximately 306,000 gallons in each basin. The analyses consider the AF System requirements, whose safety related source of water is the SX System. The UHS is designed in accordance with Regulatory Guide 1.27 (Ref. 4), which requires a 30 day supply of cooling water in the UHS. The UHS requires makeup to the basins to meet this requirement. The safety related source of makeup is the two diesel driven SX makeup pumps which take suction from the Rock River. The diesel driven SX makeup pumps auto start on low level in their associated tower basin. The SX makeup system is designed to withstand all design basis natural phenomena events and combination of events except for seismic events during low Rock River flow or level (loss of SX makeup pump suction), tornado, and river flood. Therefore, constraints on river level and flow are imposed, and if the weather is conducive to tornadoes or high river levels, plant procedures dictate proactive actions. temYl . .. "l,..r r ~.._r i .. BYRON - UNITS 1 & 2 B 3.7.9 - 3 Revision 0 INSERT B 3.7.9-1 The UHS maximum basin design temperature is 100°F. To ensure this limit is not exceeded, the cooling tower fans requirements vary with increasing SX pump discharge temperature. These requirements involve an increasing number of required cooling tower fans to be OPERABLE and whether those fans need to be running in high speed. The design analysis for determining these requirements was based on the worst-case three-hour wet bulb temperature of 82°F. For example, if SX pump discharge temperature is < 77°F, then only six of the eight cooling tower fans need to be OPERABLE and none are required to be running in high speed. If the SX pump discharge temperature is > 91'F and < 96°F, then all eight cooling tower fans need to be OPERABLE and all running in high speed_ Detailed limits are included in the LCO section. When fans are required to be running in high speed the heat transfer is credited immediately following the event because fans will automatically reenergize with the respective diesel generator output breaker auto-closure. When fans are not required to be running in high speed heat transfer is not credited until operator action opens riser valves and starts the fans. The SX pump discharge temperature limits are based on a design assumption that in the event of a LOCH, under the most severe design basis weather conditions, and a single breaker failure results in the loss of two cooling tower fans, the Operators will shed heat load by securing up to two of the four reactor containment fan coolers (RCFCs) on the LOCA unit within 30 minutes. Only one of the two trains of RCFCs is required to operate for post accident containment heat removal. When two fans are inoperable on the same bus, a postulated breaker failure could result in two additional fans being lost on the same SX cooling tower resulting in no cooling fans available on one tower and four fans available on the second tower. In this configuration the overall cooling tower performance is less than when fans are available on both towers. To support accident heat removal with two fans inoperable on the same electrical division, a lower outside air wet bulb temperature is required. An inoperable cooling tower fan is defined as being in a state such that it could not be included as a required OPERABLE fan, if necessary.

BASES APPLICABLE SAFETY ANALYSES (continued)

LCO The UHS is required to be OPERABLE and is considered OPERABLE if it has available a sufficient volume of water at or below the maximum temperature that would allow the SX System to operate for at least 30 days following the design basis event without the loss of Net Positive Suction Head (NPSH), and without exceeding the maximum design temperature of the equipment served by the SX System. Replace with INSERT B 3.7.9-2 A backup makeup source is provided by deep well pumps. The deep well system is designed for seismic, tornado, and river flood events. Each deep well pump is powered from the engineered safety feature bus for the associated tower. The deep well pumps do not include automatic start capability. To compensate for the possible time delay in providing makeup associated with a manual start of the deep well pumps, the minimum acceptable volume of water maintained in each basin is raised (903 level) and the level is verified every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The UHS satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii). desigH basis eveRt. UHS B 3.7.9 Two diesel powered SX makeup pumps must also be OPERABLE. SX makeup pump OPERABILITY includes, auto start capability on low basin level, and sufficient river level (> 664.7 ft Mean Sea Level (MSL)) and flow combinations. BYRON - UNITS 1 & 2 B 3.7.9 - 4 Revision 0 INSERT B 3.7.9-2 To meet the SX supply design temperature under postulated accident conditions a minimum number of SX cooling tower fans need to be OPERABLE to remove the postulated accident heat load. A minimum of four fans are required to support post-accident heat removal and a normal cool down of the non-accident unit when the SX pump discharge temperature is _< 77°F. A single failure could result in the loss of two fans, thus a minimum of six cooling tower fans are required to be OPERABLE. As SX pump discharge temperature increases above 77°F, additional cooling tower fan requirements are necessary. A cooling tower fan is considered OPERABLE when it has a structurally sound cooling cell, a water distribution system, and the capability of running in high speed for 30 days. The cooling tower fan requirements vary with increasing SX pump discharge temperature. The specific cooling tower fan requirements are: If SX pump discharge temperature is _< 77°F, then six cooling tower fans are required to be OPERABLE. If SX pump discharge temperature is > 77°F and _< 82°F, then either six cooling tower fans are required to be OPERABLE and all six need to be running in high speed, or seven cooling tower fans are required to be OPERABLE. If SX pump discharge temperature is > 82°F and _< 84°F, then six cooling tower fans are required to be OPERABLE and all six need to be running in high speed. If SX pump discharge temperature is > 84°F and _< 91 °F, then seven cooling tower fans are required to be OPERABLE and all seven need to be running in high speed. If SX pump discharge temperature is > 91 °F and _< 96°F, then eight cooling tower fans are required to be OPERABLE and all eight need to be running in high speed. In addition, if only six cooling tower fans are OPERABLE and the same electrical division powers the two inoperable cooling tower fans, then the outside air wet bulb temperature must be _< 76°F. An inoperable cooling tower fan is defined as being in a state such that it could not be included as a required OPERABLE fan, if necessary.

BASES APPLICABILITY In MODES 1, 2, 3, and 4, the UHS is required to support the OPERABILITY of the equipment serviced by the UHS and required to be OPERABLE in these MODES. ACTIONS INSERT B 3.7.9-4 UHS B 3.7.9 In MODE 5 or 6, the OPERABILITY requirements of the UHS are determined by the systems it supports. If one required fan is inoperable (i.e., eR y 5 faHs OPERABLE), action must be taken to restore the inoperable cooling tower fan to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . Required Action A-4 requires the remaining required OPERABLE cooling tower fans e capable of being powered by an OPERABLE emergency pa er source. This action assures availability of electri power to the remaining required fans in the unlikely eve of a loss of offsite power. The 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months Completion Time is asonable based on the fact this is an administrative check o the OPERABILITY of the emergency power sources. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time is reasonable based on the low probability of an accident occurring during the 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months that one cooling tower fan is inoperable, the number of available systems, and the time required to reasonably complete the Required Action. BYRON - UNITS 1 & 2 B 3.7.9 - 5 Revision 0 INSERT B 3.7.9-3 If there are less than the required number of cooling tower fans running in high speed, then actions must be initiated to operate all the required OPERABLE cooling cell fans in high speed. This action ensures the 100°F design temperature limit will not be exceeded during a design basis accident. The immediate Completion Time is reasonable since an OPERABLE cooling tower fan must be capable of running in high speed and the fan can be placed in this condition from the Main Control Room. Condition A is modified by a Note that indicates it is only applicable when additional cooling tower fan requirements of Table 3.7.9-1 require OPERABLE cooling tower fans to be running in high speed. INSERT B 3.7.9-4 If there are two inoperable cooling tower fans, both of which are powered by the same electrical division, and the outside wet bulb temperature exceeds 76°F, then a single failure could make all cooling tower fans inoperable on one tower. In this potential configuration, the outside air wet bulb temperature must be restricted to being < 76°F in order to keep from exceeding the design SX system temperature of 100°F. Consequently, the Required Action is to reconfigure cooling tower fans such that the two inoperable cooling tower fans are not powered by the same electrical division. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time is reasonable based on the low probability of an accident occurring during the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months timeframe in addition to a single failure disabling two cooling tower fans on the same tower that the initial two cooling tower fans were inoperable on. D.1 and D.2 If the SX pump discharge temperature exceeds 96°F, then the UHS cooling tower fans cannot prevent the design SX system temperature limit of 100°F from being exceeded during a design basis accident. Consequently, in this condition, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power in an orderly manner and without challenging plant systems.

BASES ACTIONS (continued)

---'i If one or more cooling tower basin level is < 60%, the assumptions of the design basis analyses are not met, and action must be taken to restore both basin levels within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . The 6 hour6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months Completion Time is reasonable based on the low probability of an accident occurring during the 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months that the basin level is < 60%, the number of systems available to re lenish basin level, and the time required to reasonably compete the Required Actions. G.I. G.2. and G.3 A' F.1, F.2, and F.3 UHS B 3.7.9 When one SX makeup pump is inoperable, action must be taken to verify a >_ 90% cooling tower basin level in both basins within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , and verify OPERABILITY of an associated makeup source within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The increased basin level must be verified every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months thereafter, and the inoperable SX makeup pump must be restored to OPERABLE status within 7 days or 14 days depending on plant conditions. In this Condition, the remaining OPERABLE makeup sources are adequate to perform the UHS makeup function. However, the overall reliability is reduced because failure of the OPERABLE makeup source(s) could result in a loss of the makeup function. BYRON - UNITS 1 & 2 B 3.7.9 - 6 Revision 0 BASES ACTIONS (continued)

F, F.2 UHS B 3.7.9 Required Action 1;-.4 requires verificatiln that both basin levels are >_ 90,°6, and Required Action 44 verifies the OPERABILITY of an associated makeup source (pump and flow path). The increased basin level and its verification every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months provide assurance of enough inventory in the basins to allow sufficient time to manually start makeup sources, consistent with the assumptions of the design basis analyses. An associated makeup source is a source (i.e., ESF powered deep well pump of the same train or the SX makeup pump capable of manual start) which provides makeup to the same basin served by the inoperable SX makeup pump. An SX makeup pump that is inoperable due solely to the inability to auto start on low basin level may be considered an OPERABLE associated makeup source. OPERABILITY of the same train deep well pump includes capability to start and provide sufficient flow to the associated basin. The 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to verify >_ 90% basin level and OPERABILITY of an associated makeup source is reasonable based on the low probability of a design basis accident occurring during this time period and the ability of the remaining SX makeup pump to perform the required makeup function. The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months periodic verification of >_ 90% basin level is consistent with the assumptions of the design basis analyses. BYRON - UNITS 1 & 2 B 3.7.9 - 7 Revision 0 BASES ACTIONS (continued)

T F.3 - UHS B 3.7.9 Required Action 4-.-3 requires the SX makeup pump to be restored to OPERABLE status within 7 days or 14 days respectively. The 7 day limit is applicable if both Unit 1 and Unit 2 are in MODE l, 2, 3, or 4. The 14 day limit is only applicable if either Unit 1 or Unit 2 is in MODE 5, MODE 6, or defueled. This Required Action serves to provide up to 7 days to restore a SX makeup pump when both units are operating, and up to 14 days when one unit is operating and the other is shutdown. The 14 day allowance provides adequate time to perform pump inspection and extended maintenance when one unit is in an outage. Without this allowance, a dual-unit outage would be required to perform maintenance that requires more than 7 days to complete. The extended Completion Time when one unit is in shutdown is also based on the reduction in the quantity of heat that would have to be removed by the UHS when one unit is in a shutdown condition, a reduction in the amount of water that may be required to satisfy AF demands, and the availability of the other makeup water sources. Although the 14 day Completion Time was justified based on the need to perform extended maintenance, its use and application is not restricted to these activities because the effects of SX makeup pump inoperability are unrelated to the cause of the inoperability. BYRON - UNITS 1 & 2 B 3.7.9 - 8 Revision 48 BASES ACTIONS (continued)

PA. P'2. aRd-P-- G.1, G.2, and G.3 UHS B 3.7.9 When both SX makeup pumps are inoperable, action must be taken to verify a ? 90% cooling tower basin level in both basins within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , verify OPERABILITY of at least one makeup source (pump and flow path) within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , and verify OPERABILITY of a second makeup source serving the other tower basin within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The increased basin level must be verified every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months thereafter. G.1 and G.2 In this Conditi.W, the UHS makeup function may not be met. Req uired Actions P.' and n. require verification of the OPERABILITY of at least one makeup source and verification that both basin levels are >_ 90%. The increased basin level and its verification every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months allows sufficient time to manually start makeup sources, consistent with the assumptions of the design basis analyses. An SX makeup pump which is inoperable solely due to the inability to auto start on low basin level may be considered an OPERABLE makeup source. The 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months Completion Time is reasonable based on the low probability of an accident occurring during the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and the time required to reasonably complete the Re uired Actions. G.3 Required Action -3 requires verification of the OPERABILITY of a second makeup source within 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With the plant only having one OPERABLE makeup source, the UHS makeup function can be performed; however the overall reliability is reduced. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time is reasonable based on the low probability of an accident occurring during this time period and the available makeup capability. BYRON - UNITS 1 & 2 B 3.7.9 - 9 Revision 0 BASES ACTIONS (continued)

UHS B 3.7.9 ¬4 With the Rock River water level <_ 670.6 ft Mean Sea Level (MSL), action must be taken to assure that adequate level and flow remain available from the Rock River intake to the SX makeup pumps to permit their operation. When the water level in the river falls below this limit, within one hour, and every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months thereafter, the water level in the river must be verified to be greater than 664.7 ft MSL and the flow rate in the river must be verified to be greater than or equal to 700 cubic feet per second (CFS). 700 cfs assures adequate inventory is available for the pumps to maintain the level in the UHS basins. 664.7 ft is the minimum design operating level of the SX makeup pumps. Assuring adequate inventory and a level greater than the minimum operating level provides assurance that the pumps can perform their function if required. The 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months Completion Time for initial performance of this Required Action is reasonable based on the low probability of an accident occurring during the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and the time required to reasonably complete the Required Actions. The continued performance of this verification every 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is reasonable based on the availability of other makeup sources and the low likelihood of an accident and a rapid unexpected decrease in the river level. BYRON - UNITS 1 & 2 B 3.7.9 - 10 Revision 48 BASES ACTIONS (continued)

F.I. P.2. aRd FA 1.1. 1.2, and 1.3 J UHS B 3.7.9 The SX makeup pumps provide the safety-related*nakeup capability to the UHS, however when Condition 1= applies, the pumps may not be capable of performing the required function. With water level or flow in the Rock River outside of the limits specified, the pumps may not have adequate NPSH or inventory to supply the required makeup to the UHS if an accident occurs. If water level is forecast to exceed 702 ft MSL on the Rock River, the SX makeup pumps may be subjected to flooding that would render them inoperable. Similarly, if a Tornado Watch exists that includes the Byron site, the pumps may not be capable of performing their required function because the river screen house that contains the pumps is not designed to protect them from a tornado. In these conditions, alternative makeup capability to the UHS must be available and the inventory in the UHS basin must be large enough to permit manual initiation of the alternative source. The deep well pumps supply the alternative makeup capability to the UHS. To assure adequate inventory in the UHS to permit a delay in makeup for manual initiation of the deep well pumps, the level in each tower basin must be verified to be greater than or equal to 90% within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , and every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months thereafter. The 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months Completion Time for initial performance of this Required Action is reasonable based on the low probability of an accident occurring during the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and the time required to reasonably complete the Required Actions. The continued performance of this verification every 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months is reasonable based on the low likelihood of an accident and the maximum expected decrease in level in the UHS basin. In addition, at least one deep well pump must be verified OPERABLE within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months . This assures that if an accident occurs, adequate makeup capability to the UHS is available. The 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months Completion Time for initial performance of this Required Action is reasonable based on the low probability of an accident occurring during the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and the time required to reasonably complete the Required Actions. BYRON - UNITS 1 & 2 B 3.7.9 - 11 Revision 0 BASES ACTIONS (continued)

E. F. G. H. or I BYRON - UNITS 1 & 2 Within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , both Ikep well pumps must be verified to be OPERABLE if Condition -P continues to apply. This Required Action is consistent with the need to assure reliable and redundant supplies are available to provide makeup to the UHS. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time is reasonable based on the low probability of an accident occurring during the 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months coincident with a failure of the OPERABLE deep well pump. SURVEILLANCE SR 3.7.9.1 REQUIREMENTS UHS B 3.7.9 If the UHS cannot be restored to OPERABLE status within the associated Completion Times or the associat(I Required Actions are not met of Condition A, B, C, D, 9P --F, or if the UHS is inoperable for reasons other than Condition A, B, C, P, E, 9P P, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in at least MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging plant systems. This SR verifies adequate basin level to provide time to manually establish makeup while providing auxiliary feedwater if required. The specified level also ensures that sufficient NPSH is available to operate the SX pumps. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Frequency is based on operating experience related to trending of the parameter variations during the applicable MODES. This SR verifies that the UHS cooling tower basin water level is >_ 60%. B 3.7.9 - 12 Revision 0 BASES SURVEILLANCE REQUIREMENTS (continued)

INSERT B 3.7.9-5 SR 3.7,9.2 UHS B 3.7.9 This SR verifies that the UHS is capable of supporting the SX System. In turn, availability of the UHS ensures the ability of the SX System to cool the CC System to at least its maximum design temperature with the maximum accident or normal design heat loads for 30 days following a Design Basis Accident and cool the other components served directly by the SX System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Frequency is based on operating experience related to trending of the parameter variations during the applicable MODES. This SR ver ifies U a , ,- 4TfJ ono PHnninn nn -Spe ed; ep ! , 960 P 4 -~- OPERABLE GGel ,~g we 4aHs rinni nn nn high spee4 SR 3.7.9.3 This SR verifies the SX makeup pumps are OPERABLE by ensuring river water level and flow are sufficient for proper operation of the SX makeup pumps in case of the Design Basis Accident (DBA). If the river water level is > 670.6 ft MSL and _< 702.0 ft MSL, proper operation is assured. If the water level is > 702.0 ft MSL, the pump s may become flooded and not be available. If the river level is <_ 670.6 ft MSL, proper operation of the pumps during a DBA is possible. However, the river level must be > 664.7 ft MSL and river flow must be > 700 cfs. The frequency of SR 3.7.9.3 is based on the potential for changes in river level on a daily basis. SR 3.7.9.4 Starting from the control room and operating each required cooling tower fan on high speed for _> 15 minutes (if not already operating in high speed) ensures that all fans are OPERABLE and that all associated controls are functioning properly. It also ensures that fan or motor failure, or excessive vibration, can be detected for corrective action. The 31 day Frequency is based on operating experience, the known reliability of the fan units, the redundancy available, and the low probability of significant degradation of the UHS cooling tower fans occurring between surveillances. BYRON - UNITS 1 & 2 B 3.7.9 - 13 Revision 0 INSERT B 3.7.9-5 This SR verifies a minimum of six OPERABLE cooling tower fans when SX pump discharge temperature is _< 77°F. The SR is modified by a Note that stipulates that if SX pump discharge temperature is greater than 77°F, then the additional cooling tower fan requirements of Table 3.7.9-1 shall be met. Table 3.7.9-1 contains the additional cooling tower fan requirements when SX pump discharge temperature is greater than 77°F. These additional requirements include the number of required OPERABLE cooling tower fans and whether they need to be running in high speed. The Additional Requirements column is modified by a footnote to indicate when in Condition B, the number of OPERABLE cooling tower fans required to be running in high speed is one less than indicated.

BASES SURVEILLANCE REQUIREMENTS (continued)

SR- 37-9 5 UHS B 3.7.9 Verifying the correct alignment for manual, power operated, and automatic valves in the SX makeup flow path provides assurance that the proper flow paths exist for SX makeup operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This SR does not require any testing or valve manipulation

rather, it involves verification that those valves capable of being mispositioned are in the correct position. This SR does not app1 y to valves that cannot be inadvertently misaligned, such as check valves. The 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions. SR 3.7.a,6 This SR verifies that each SX makeup pump starts and operates on an actual or simulated) ow basin level signal for >_ 30 minutes. The 31 day frequency is based on operating experience and the low probability of significant degradation of the SX makeup pump occurring between performances of the surveill ance. SR 3.7.9.7 This SR provides verification that the level of fuel oil in the day tank is at or above the level that provides approximately a 3 day supply of fuel for the pumps. This is enough time to arrange for addition of more fuel if needed. The level is expressed as a percent of the usable volume of the tank. The 479 indicated level ensures that there is at least 864 gallons of usable fuel to each diesel powered essential service water makeup pump, with an allowance for instrumentation tolerances. The 31 day Frequency is adequate to assure that a sufficient supply of fuel oil is available, since low level alarms are provided and facility operators will be aware of any large uses of fuel oil during this period. BYRON - UNITS 1 & 2 B 3.7.9 - 14 Revision 56 BASES SURVEILLANCE REQUIREMENTS (continued)

INSERT B 3.7.9-6 SR 3.7_.9,8 UHS B 3.7.9 This SR requires that each testable valve in the SX makeup system flow path be cycled through at least one complete cycle of travel every 18 months. This SR applies to the flow path from the SX makeup pumps to the UHS basins. The SR provides assurance that if a flow path is required, it can be aligned properly. The 18 month Frequency is based on the low probability of an undetected failure, and is consistent with testing required by the IST program. SR 3.7.9.9 The tests of fuel oil are a means of assuring it has not been contaminated with substances that would have an immediate, detrimental impact on diesel engine combustion. The tests, limits, and applicable ASTM Standards are listed in the Diesel Fuel Oil Testing Program in Specification 5.5.13. Fuel oil degradation during long term storage shows up as an increase in particulate, due mostly to oxidation. The presence of particulate does not mean the fuel oil will not burn properly in a diesel engine. The particulate can cause fouling of filters and fuel oil injection equipment, however, which can cause engine failure. Particulate concentrations should be determined in accordance with ASTM D5452 (Ref. 5). This method involves a determination of total particulate concentration in the fuel oil and has a limit of 10 mg/l. It is acceptable to obtain a field sample for subsequent laboratory testing in lieu of field testing. Fuel Oil to the Essential Service Water Makeup Pump Day Tanks is supplied from the outside fuel oil storage tanks. These tanks are also subject to the requirements of the Diesel Fuel Oil Testing Program, as described in Specification 5.5.13. The Frequency of this test takes into consideration fuel oil degradation trends that indicate that particulate concentration is unlikely to change significantly between Frequency intervals. BYRON - UNITS 1 & 2 B 3.7.9 - 15 Revision 51 INSERT B 3.7.9-6 SR 3.7.9.10 This SR verifies the outside air wet bulb temperature is _< 76°F. The SR is modified by a Note indicating that the SR is only required to be performed when two inoperable cooling tower fans are powered by the same electrical division. If there are two inoperable cooling tower fans, both of which are powered by the same electrical division, and the outside air wet bulb temperature exceeds 76°F, then a single failure could make all cooling tower cells inoperable on one tower. In this potential configuration, the outside air wet bulb temperature must be restricted to being _< 76°F in order to keep from exceeding the design SX system temperature of 100°F. The 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Frequency is reasonable to account for daily fluctuations in outside air wet bulb temperature.

BASES REFERENCES 1. UFSAR, Section 9.2.5. 2. Commonwealth Edison letter to Dr. Thomas E Murley dated January 9, 1992. 3. Commonwealth Edison letter to Dr. Thomas E Murley dated March 31, 1992. 4. Regulatory Guide 1.27. 5. ASTM Standards, D5452. 6. Commonwealth Edison letter to USNRC Document Control Desk dated May 6, 1997. Exelon Generation Company, LLC letter to USNRC Document Control Desk dated June 30, 2009. UHS B 3.7.9 BYRON - UNITS 1 & 2 B 3.7.9 - 16 Revision 21 ATTACHMENT 4 Analytical Basis for the Proposed Changes to the Cooling Tower Basin Temperature Limits Analytical Basis for Proposed Changes to Tech nical Specifications Pages Fill through H107 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H1 APPENDIX H Scenarios 8A, 813, 8C, 8C1, 8C2, 8D, and 8D1 Evaluations (CALCULATION NO. NED-M-MSD-009 REVISION NO 8, Appendix H PAGE H2 1.0 PURPOSE The purpose of this Appendix is to incorporate additional scenarios 8A, 813' 8C, 8C1, 8C2, 8D, and 8D1 for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCA and a LOOP on one unit with the opposite unit in normal shutdown as described in UHS-01 [Ref. 4.3]. This appendix provides the analytical basis for proposed changes to Technical Specifications surveillance of SX cooling tower basin temperatures. 2.0 DESIGN INPUTS The design inputs specified in Revisions 0 through 7 of this calculation apply to the present revision except the following: 2.1 SX water inventory per tower is equal to the basin volume of 59%, or 40,578 ft 3 [Ref. 4.9], which is one percent below the Technical Specification minimum value of 60% [Ref. 4.5]. The volume of water in the return and supply piping of 34,043 ft 3 is then added [Ref. 4.6] to the basin volume. The volume of silt in the basin (3,312 ft 3 per basin per Ref. 4.7) is subtracted from the SX water inventory used for the calculation so that it is not included as part of the heat sink. The total (for both towers) SX water inventory volume = [(40,578-3,312) ft 3 +34,043 ft 3] per tower x 7.48 gal/ft 3 x 2 towers = 1.068 x 10 6 gallons. 2.2 The accident scenarios used in this revision of the calculation are taken from UHS-01 [Ref. 4.3] Attachment B and are consistent with scenarios 8A, 813, 8C, 8C1, 8C2, and 8D in BYR96-259

[Ref. 4.2] and BYR97-127

[Ref. 4.1]. 2.3 Flows through the two trains of the SX tower for accident scenarios 8A, 813, SC, 8C1, 8C2, and 8D are taken from BYR96-259, Rev. 2 [Ref. 4.2] Attachment C, and BYR97-127

[Ref. 4.1] Attachment C, and are discussed in more detail in Section 7.1. 2.4 LOCA unit heat loads are taken from Table 11 of ATD-0063, Rev. 4B [Ref. 4.4]. These heat loads include non-accident heat loads, accident heat loads, and miscellaneous heat loads. 2.5 Cooling tower performance curves for scenarios 8A, 813, 8C, 8C1, 8C2, and 8D are based on tower performance data from scenarios 8A, 813, 8C, 8C1, 8C2, and 8D of BYR97-127, Rev. 1 [Ref. 4.1]. Scenario 8C1 is run at wet bulb temperatures of 82°F and 76°F. The 76°F wet bulb tower performance curve is used in this analysis as discussed in Section 6.1. 2.6 The cooling tower riser flow rates used in this calculation have 250 gpm subtracted from them, as described in Appendix D of this calculation. 3.0 ASSUMPTIONS All assumptions in the calculation main body are valid for this Appendix H calculation. 3.1 The fraction of water cooled for SX cooling tower cells with fans not running is assumed to be 0.10 (i.e., 10% of the water delivered to that cell is effectively cooled). This is based on input from the cooling tower manufacturer as a reasonable estimate of minimum cooling tower performance without fan air flow [Ref. 4.8]. See Appendix I of this calculation for a more detailed analysis to justify this assumption. For scenarios where a tower has at least one active cell, tower performance curves are based on the average flow to the active cells. This approach is justified since the majority of the cooling is provided by the active cells, and the difference in flow between tower cells is small. For CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H 3 Tower B in scenario 8C1, there are no active cells. In this case, the tower performance curve is based on the average flow to the passive cells. 3.2 Consistent with Technical Specification 3.7.9 [Ref. 4.5], an initial maximum basin temperature of 96°F with seven or more fans running and an initial maximum temperature of 90°F with less than seven fans running are used. For those scenarios which exceed the SX design temperature of 100°F, with an initial basin temperature of 96°F or 90°F, a new lower initial maximum cold water basin temperature will be determined which will maintain the basin temperature below 100°F. These new initial basin temperatures will become the basis for changes to Technical Specification 3.7.9. 3.3 For scenarios 8D and 8D1, no cooling is credited prior to fan initiation at 10 minutes. 3.4 The heat loads taken from Table 11 of ATD-0063, Rev. 4B [Ref. 4.4] assume that half the RCFC heat load on the accident unit is shed at, or prior to, 30 minutes. Since no procedures are currently in place to implement this operator action, this assumption is considered unverified. (UNVERFIFED)

4.0 REFERENCES

4.1 BYR97-127, Rev. 1, "Byron Ultimate Heat Sink Cooling Tower Performance Calculations

." 4.2 BYR96-259, Rev. 2, "SX System FLO-Series Analysis." 4.3 Attachment B to UHS-01, Rev. 4, "Ultimate Heat Sink Design Basis LOCA Single Failure Scenarios." 4.4 ATD-0063, Rev. 4B, "Heat Load to the Ultimate Heat Sink During a Loss of Coolant Accident." 4.5 Byron Technical Specifications 3.7.9, Amendment 159. 4.6 BYR97-034, Rev. OA, "Essential Service Water Cooling Tower Basin Minimum Volume Versus Level and Minimum Usable Volume Calculation," June 28, 2005. 4.7 SX-TH01, Rev. 0, "Water Volume in SX System Outdoor Piping & SX Tower Basin," June 25, 1987. 4.8 Email from Paul Secen (SPX) to M.A. Nena (S&L) dated July 18, 2008 1:05 PM, subject: Re: Mechanical Draft Cooling Tower Performance With Inoperable Fans (see page H 107). 4.9 NED-M-MSD-014, Rev. 008A, "Byron Ultimate Heat Sink Cooling Tower Basin Makeup Calculation

." 5.0 IDENTIFICATION OF COMPUTER PROGRAMS The maximum service water temperature was determined by running Mathcad Version 11.2a, Program Number 03.7.548-11.2. All computer runs using Mathcad were made on Sargent and Lundy L.L.C. PC No. ZL4512 from Controlled File Path: C:\Program Files\MathSoft\Mathcad 11 Enterprise Edition\.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H 4 6.0 METHOD OF ANALYSIS Appendix H of this calculation will use the ESW cooling tower transient model from Appendix G of this calculation to calculate the basin temperature response for additional scenarios 8A, 8B, 8C, 8C1, 8C2, 8D, and 8D1. Revisions to the Appendix G Mathcad model required to perform the Appendix H analysis are summarized as follows: 1) The revised Total Heat Load to the UHS curve from ATD-0063 [Ref. 4.4] (Table 11) will be incorporated. This curve is the summation of the non-accident unit RHR heat load, the accident heat load, and the miscellaneous heat load from both units. 2) New scenarios 8A, SB, 8C, 8C1, 8C2, 8D, and 8D1 are being evaluated for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCA and a LOOP on one unit with the opposite unit in normal shutdown as described in UHS-01 [Ref. 4.3]. 3) For scenarios 8A, 8B, 8C, 8C1, 8C2, 8D, and 8D1 new flow rates and tower performance curves were generated

[Ref.'s 4.2 and 4.1] and are used as inputs. 4) Partial credit is taken for cooling (10%) in tower cells with water flow but no fan in operation (see Assumption 3.1). For scenarios where a tower has at least one active cell, tower performance curves are based on the average flow to the active cells. This approach is justified since the majority of the cooling is provided by the active cells, and the difference in flow between tower cells is small. For Tower B in scenario 8C1, there are no active cells. In this case, the tower performance curve is based on the average flow to the passive cells. The Byron ESW cooling tower performance is acceptable if the calculated basin temperature is below the SX cooling tower basin design temperature of 100°F. 6.1 Scenario 8C1 76°F Wet Bulb Temperature When Scenario 8C1 was run with 10% passive fan cooling, reduced miscellaneous heat load, and RCFC heat load shed at 30 minutes, the maximum basin temperature was greater than 100°F. Scenario 8C1 assumes two SXCT fans powered by the same bus are out of service (OOS). Taking two fans OOS on the bus generally occurs during planned maintenance windows on the bus. To facilitate maintenance, the wet bulb temperature was varied to obtain an acceptable basin temperature. 6.2 Tower Performance Curves The tower performance curves are shown in Figures H-1 through H-6 for each scenario. These figures plot TH ot vs Tco,d for each tower performance curve for each cooling tower as provided by BYR97-127

[Ref. 4.1]. For each scenario, two points were selected from the applicable tower performance curve to provide a linear approximation of tower performance over the range of T Hot and Tco,d temperatures expected for that scenario. The selected points are checked against final results to confirm their applicability to the actual temperature range. These points are listed as Th1, Th2, Th3, Th4, Tc1, Tc2, Tc3, and Tc4 in the Mathcad models. 7.0 NUMERICAL ANALYSIS Operator Actions - All accident scenarios evaluated in this Appendix credit operator action to reduce the heat load rejected to the UHS within 30 minutes post-LOCA by securing fans on two of four RCFCs.

(CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H5 7.1 Flow Rate Analysis As discussed in BYR96-259

[Ref. 4.2] and BYR97-127

[Ref. 4.1], leakage is taken into account when determining the average flow rates. Also, in order to account for 10% cooling for passive fans (see Assumption 3.1), the flow rate for that cell is multiplied by 0.1 after leakage is taken into account as shown in the tables below. To calculate the flow through the operating cells 250 gpm is subtracted from each open riser to account for the flow in the open 2" riser leak-off line (see Design Input 2.6). 7.1.1 Accident Scenario 8A The single failure considered for Scenario 8A is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 96°F with one SX pump running on each unit. This scenario assumes no tower cells are out of service (OOS). Initially, the fans on all the cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 4B [Ref. 4.4], with half of the RCFC heat load subtracted after 30 minutes. There is one set of parameters f, Q, M1, 131, M2, B2, a, and /3 that are needed to determine the basin temperature response. The UHS tower flows, based on Scenario 8A are shown in Design Input 2.3. The Thot vs Twld relationship is illustrated in Figure H-1. Determination of f, Q, M1, B1, M2, B2, a, and R. Scenario 8C1 Scenario 8C2 Scenario 81) Flow through operating cells in T1 9,403 + 9,292 + 9,241 + 9,228 -1000 = 36,163 12,614+12,598-500=

24,712 10,450+10.393+10,379-750 = 30,472 4.2 Total flow through T1 9,403 + 9,292 + 9,241 + 9,228 + 797 = 37,960 12,614 + 12,598 + 280 + 278 + 856 = 26,626 10,450 + 10,393 + 10,379 + 284 + 815 = 32,322 4.2 Flow through o ratin cells in T2 (12,672-250)'0

.1 +(12,652 250)'0.1 = 2,482 9,254+9,239-500+

(9,424-250)'0

.1 +(9,307 250)'01 =19,816 10,411-250+(10,506-250)'0" 1 +(10,445-250r0.1 =12,206 4.2 Total flow throu h T2 672 + 12,652 + 270 + 270 1- +/- 851 = 26,716 I 9,424 + 9,307 + 9,254 + 9,239 + 793 = 38,018 l 10,411 + 10,506 + + 273 + 812 10,445I = 32,446 ) 4.2 ~ - I i :rr Scenario 8A Scenario 8B/BD1 Scenario 8C Flow through operating cells in T1 8,074+7 ,978+7,933+

7,922 - 1000 = 30907 8,530 + 8,429 + 8,383 + 8,371 - 1000 = 32,713 10,450 + 10,394 + 10,380 750 = 30,474 - 4.2 Total flow through T 1 8,074 + ,933 + 7,922 + 778 7, 978:37 2 685 8,530 + 8,429 + 8,383 + 8,371 + 784 = 34,497 10,450 + 10,394 + 10,380 + 284 + 815 = 32,323 4.2 Flow throu ti cells in T2 7,859+7,847-500+(8,005

-250)'0.1 +(7,906- 250 "0.1 =16 16,747 9,757-250+(9,846-250)'0.1 +(9,788- 250)'0.1 =11 11,420 10,412-250+(10,507-250)'0.1 +(10,445-250 '0.1 = 12,207 4.2 Total flow through T2 ~. 8,005 + 7,906 + 7,859 + 7,847 + 774 = 32,391 I 9,848 + 9,788 + 256 + 9,757 + 801 = 30,448 I 10,507 + 10,445 + 273 + 10,412 + 811 = 32_448 L - 4.2 m" :m CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H6 f11, f12: f21. f22 Q1, Q2 _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 30,907 gpm = 0.946 32,685 gpm Flow through operating cells in T2 Total flow through T2 including bypass flow = 16,747 gpm = 0.517 32,391 gpm This is equal to the total flow to T1 and T2, (32,685 + 32,391) gpm = 65,076 gpm M11, B11, M12, B12 a1, a2: Based on an average flow of 7,727 gpm per cell in T1, the tower performance for T1 is generated using a flow of 7,727 gpm (Figure H-1). Based on the T H , T c values (as determined from the TH values calculated for tower operation in Design Input 2.5), [(119.02, 91.02), (111.8, 89.8)], Mathcad calculates M11, M12 and 1311, B12 from the tower performance inputs. M21, B21, M22, B22 Based on an average flow of 7,603 gpm per cell in T2, the tower performance for T2 is generated using a flow of 7,603 gpm (Figure H-1). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(118.79, 90.79), (111.6, 89.6)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. Flow to T1 = 32,685 gpm = 0.502 Total SX flow, Q 65,076 gpm R is estimated as the fraction of load to Tower 1. Flow to RCFC 1 A (3,184) gpm - - = 0.530 Flow to RCFC 1 A + Flow to RCFC 1 B (3,184 + 2,825) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (3), renamed AVA2, D1/D2, and C1/C2 here, are calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages H23 through H29. The maximum basin temperature, Tb ma ,, is calculated to be 98.6°F. The (CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H7 temperature at 30 minutes is calculated to be 98.3°F. Both of these values are below the acceptance limit of 100°F. 7.1.2 Accident Scenario 8B The single failure considered for Scenario 8B is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 96°F with one SX pump running on each unit. This scenario assumes one tower cell (G) is out of service (OOS). Initially, the fans on all the cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 413 [Ref. 4.4], with half of the RCFC heat load subtracted after 30 minutes. There is one set of parameters f, Q, M1, B1, M2, B2, a, and R that are needed to determine the basin temperature response. The UHS tower flows, based on Scenario 8B are shown in Design Input 2.3. The Thos VS Told relationship is illustrated in Figure H-2. Determination of f, Q, M1, B1, M2, B2, a, and R. f11, f12 Total flow through T1 including bypass flow f21, f22 Q1, Q2 Flow through operating cells in T1 = 32,713 gpm = 0.948 34,497 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow = 11,420 gpm = 0.375 30,448 gpm This is equal to the total flow to T1 and T2, (34,497 + 30,448) gpm = 64,945 gpm M11, B11, M12, B12: Based on an average flow of 8,178 gpm per cell in T1, the tower performance for T1 is generated using a flow of 8,178 gpm (Figure H-2). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(119.86, 91.86), (112.54, 90.54)], Mathcad calculates M11, M12 and 611, B12 from the tower performance inputs.

I CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H8 M21, B21, M22, B22: a1, a2 131, 2: 7.1.3 Accident Scenario 8C Based on an average flow of 9,507 gpm per cell in T2, the tower performance for T2 is generated using a flow of 9,507 gpm (Figure H-2). Based on the T H , T C values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(122.47, 94.47), (114.86, 92.86)), Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. Flow to T1 = 34,497 gpm = 0.531 Total SX flow, Q 64,945 gpm R is estimated as the fraction of load to Tower 1. __ Flow to RC FC 1 A = (3,173) gpm = 0,530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,173 + 2,813) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (3), renamed A1/A2, D1/D2, and C1/C2 here, are calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages H30 through H43. The maximum basin temperature, Tbr,,ax, is calculated to be 101.5°F with an initial basin temperature of 96°F (current Tech Spec limit). The maximum basin temperature, Tbmax, is calculated to be 99.6°F with an initial basin temperature of 91°F (new Tech Spec limit). The temperature at 30 minutes is calculated to be 99.6°F with an initial basin temperature of 91'F. Both of these values (with new Tech Spec limit) are below the acceptance limit of 100°F. The single failure considered for Scenario 8C is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 90°F with one SX pump running on each unit. This scenario assumes two tower cells (A and G) are out of service (OOS). Initially, the fans on all the other cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 4B [Ref. 4.4], with half of the RCFC heat load subtracted after 30 minutes. There is one set of parameters f, Q, M1, B1, M2, B2, a, and R that are needed to determine the basin temperature response. The UHS tower flows, based on Scenario 8C are shown in Design Input 2.3. The Th ot VS T,o,d relationship is illustrated in Figure H-3. Determination of f, Q, M1, B1, M2, B2, a, and 0.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H9 f11. f12 f21. f22 Q1, Q2 al. a2 61.02: _ Flow through operating cells in T1 Total flow through T1 including bypass flow 30,474 gpm = 0.943 32,323 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow 12,207 gpm = 0,376 32,448 gpm This is equal to the total flow to T1 and T2, (32,323 + 32,448) gpm = 64,771 gpm M11, B11, M12-1312: Based on an average flow of 10,158 gpm per cell in T1, the tower performance for T1 is generated using a flow of 10,158 gpm (Figure H-3). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(123.81, 95.81), (116.07, 94.07)], Mathcad calculates M11, Ml 2 and 1311, 1312 from the tower performance inputs. M21, 1321, M22, B22: Based on an average flow of 10,162 gpm per cell in T2, the tower performance for T2 is generated using a flow of 10,162 gpm (Figure H-3). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(123.82, 95.82), (116.08, 94.08)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. Flow to T1 = 32,323 gpm = 0.499 Total SX flow, Q 64,771 gpm P is estimated as the fraction of load to Tower 1. __ Flow to RC FC 1A (3,157) gpm = 0.530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,157 + 2,800) gpm Based on the parameters f, Q, M1, 131, M2, B2, a, and P determined above, the coefficients A, B, and C in Eq (3), renamed A1/A2, D1/D2, and C1/C2 here, are calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages H44 through H57. The maximum basin temperature, Tbm., is calculated to be 101.6°F with CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H10 an initial basin temperature of 90°F (current Tech Spec limit). The maximum basin temperature, Tbmax, is calculated to be 99.9°F with an initial basin temperature of 84°F (new Tech Spec limit). The temperature at 30 minutes is calculated to be 99.1°F with an initial basin temperature of 84°F. Both of these values (with new Tech Spec limit) are below the acceptance limit of 100°F. 7.1.4 Accident Scenario 8C1 This scenario is the same setup as Scenario 8C with the exception that cells G and H are postulated to be OOS as opposed to cells A and G. The single failure considered for Scenario 8C1 is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 90°F with one SX pump running on each unit. This scenario assumes two tower cells (G and H) are out of service (OOS). Initially, the fans on all the other cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 413 [Ref. 4.4], with half of the RCFC heat load subtracted after 30 minutes. There is one set of parameters f, Q, M1, B1, M2, B2, a, and 0 that are needed to determine the basin temperature response. The UHS tower flows, based on Scenario 8C1 are shown in T co , d relationship is illustrated in Figure H-4. Determination of f, Q, M1, B1, M2, B2, a, and R. f11. f12 f21. f22 Q1 Q2_: _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 36,163 gpm = 0.953 37,960 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow = 2,482 gpm = 0.093 26,716 gpm Design Input 2.3. The T hat vs This is equal to the total flow to T1 and T2, (37,960 + 26,716) gpm = 64,676 gpm M11 B11, M12-512: Based on an average flow of 9,041 gpm per cell in T1, the tower performance for T1 is generated using a flow of 9,041 gpm (Figure H-4). Based on the T H , T c values (as determined from the T H values calculated for tower operation in CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H11 M21 B21 M22, B22: a1. a2 (31. 132: 7.1.5 Accident Scenario 8C2 Design Input 2.5), [(119.23, 91.23), (111.53, 89.53)], Mathcad calculates M11, M12 and B11, B12 from the tower performance inputs. Based on an average flow of 12,412 gpm per cell in T2, the tower performance for T2 is generated using a flow of 12,412 gpm (Figure H-4). Based on the T H , T C values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(113.20, 85.20), (106.20, 84.20)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. - Flow to T1 - 37,960 gpm = 0.587 Total SX flow, Q 64,676 gpm R is estimated as the fraction of load to Tower 1. __ Flow to RC FC 1 A = (3,149) gpm = 0.530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,149 + 2,792) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and (3 determined above, the coefficients A, B, and C in Eq (3), renamed A1/A2, D1/D2, and C1/C2 here, are calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages H58 through H71. The maximum basin temperature, Tbmax, is calculated to be 101.9°F with an initial basin temperature of 90°F (current Tech Spec limit). The maximum basin temperature, Tbmax, is calculated to be 99.7°F with an initial basin temperature of 84°F (new Tech Spec limit). The temperature at 30 minutes is calculated to be 99.2°F with an initial basin temperature of 84°F. Both of these values (with new Tech Spec limit) are below the acceptance limit of 100°F. The wet bulb temperature was lowered from 82°F to 76°F for this scenario to maintain Tbmax below 100°F. This scenario is the same setup as Scenario 8C with the exception that cells A and B are postulated to be OOS as opposed to cells A and G. The single failure considered for Scenario 8C2 is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 90°F with one SX pump running on each unit. This scenario assumes two tower cells (A and B) are out of service (OOS). Initially, the fans on all the other cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 413 [Ref. 4.4], with half of the RCFC heat load subtracted at 30 minutes. There is one set of parameters f, Q, M1, 131, M2, 62, a, and P that are needed to determine the basin temperature response.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H12_ The UHS tower flows, based on Scenario 8C2 are shown in Design Input 2.3. The T ho , vs T, o , d relationship is illustrated in Figure H-5. Determination off, Q, M1, B1, M2, B2, a, and R. f11, f12 f21. f22 Q1 Q2: a1, a2 01, 02 Flow through operating cells in T1 Total flow through T1 including bypass flow = 24,712 gpm = 0.928 26,626 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow 19,816 gpm = 0.521 38,018 gpm This is equal to the total flow to T1 and T2, (26,626 + 38,018) gpm = 64,644 gpm M11, B11, M12. B12: Based on an average flow of 12,356 gpm per cell in T1, the tower performance for T1 is generated using a flow of 12,356 gpm (Figure H-5). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(120.45, 98.45), (111.59, 95.59)], Mathcad calculates M11, M12 and B11, B12 from the tower performance inputs. M21, B21, M22, B22: Based on an average flow of 8,997 gpm per cell in T2, the tower performance for T2 is generated using a flow of 8,997 gpm (Figure H-5). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(121.44, 93.44), (113.95, 91.95)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. = Flow to T1 = 26,626 gpm = 0.412 Total SX flow, Q 64,644 gpm R is estimated as the fraction of load to Tower 1. __ Flow to RC FC 1 A __ (3,145) gpm = 0.530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,145 + 2, 791) gpm CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H13 Based on the parameters f, Q, M1, B1, M2, 62, a, and R determined above, the coefficients A, B, and C in Eq (3), renamed AVA2, D1/D2, and C1/C2 here, are calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages H72 through H85. The maximum basin temperature, Tbmax, is calculated to be 101.3°F with an initial basin temperature of 90°F (current Tech Spec limit). The maximum basin temperature, Tbmax, is calculated to be 99.8°F with an initial basin temperature of 85°F. The temperature at 30 minutes is calculated to be 99.1 °F with an initial basin temperature of 85°F. Both of these values (with new Tech Spec limit) are below the acceptance limit of 100°F. 7.1.6 Accident Scenario 8D This scenario is the same setup as Scenario 8C with the exception that no fans are running initially. No cooling is credited prior to fan initiation at 10 minutes (see Assumption 3.3). The single failure considered for Scenario 8D is the loss of power to Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 80°F with one SX pump running on each unit. This scenario assumes two tower cells (A and G) are out of service (OOS). Initially, no fans on all the other cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 4B [Ref. 4.4], with half of the RCFC heat load subtracted at 30 minutes. There is one set of parameters f, Q, M1, B1, M2, B2, a, and R that are needed to determine the basin temperature response. The UHS tower flows, based on Scenario 8D are shown in Design Input 2.3. The Thot VS T,o,d relationship is illustrated in Figure H-6. Determination of f, Q, M1, B1, M2, B2, a, and R. f11, f12 _ Flow through operating cells in T1 Total flow through T1 including bypass flow f21. f22 = 30,472 gpm = 0.943 32,322 gpm F low through operating cells in T2 Total flow through T2 including bypass flow 12,206 gpm = 0.376 32,446 gpm CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H14 This is equal to the total flow to T1 and T2, (32,322 + 32,446) gpm = 64,768 gpm M11, B11, M12, 612: Based on an average flow of 10,157 gpm per cell in T1, the tower performance for T1 is generated using a flow of 10,157 gpm (Figure H-6). Based on the T H , T c values (as determined from the TH values calculated for tower operation in Design Input 2.5), [(123.81, 95.81), (116.07, 94.07)], Mathcad calculates M11, M12 and B11, B12 from the tower performance inputs. M21-R2 1, M22 622: a1. a2: (31, (32 7.1.7 Accident Scenario 8D1 Based on an average flow of 10,161 gpm per cell in T2, the tower performance for T2 is generated using a flow of 10,161 gpm (Figure H-6). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.5), [(123.82, 95.82), (116.07, 94.07)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. - Flow to T1 = 32,322 gpm = 0.499 Total SX flow, Q 64,768 gpm (3 is estimated as the fraction of load to Tower 1. __ Flow to RCFC 1A = (3,157) gpm = 0.530 Flow to RCFC 1A +Flow to RCFC 1 B (3,157 + 2,800) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and P determined above, coefficients A, B, and C in Eq (3), renamed A1/A2, D1/D2, and C1/C2 here, calculated by Mathcad. the are The output from the MathCAD calculation for this scenario is shown on pages H86 through H99. The maximum basin temperature, Tbmax, is calculated to be 100.7°F with an initial basin temperature of 80°F (current Tech Spec limit). The maximum basin temperature, Tbmax, is calculated to be 99.7°F with an initial basin temperature of 77°F (new Tech Spec limit). The temperature at 30 minutes is calculated to be 98.8°F with an initial basin temperature of 77°F. Both of these values (with new Tech Spec limit) are below the acceptance limit of 100°F. This scenario is the same setup as Scenario 8B with the exception that no fans are running initially. No cooling is credited prior to fan initiation at 10 minutes (see Assumption 3.3). The single failure considered for Scenario 8D1 is the loss of power to Cells E and F cooling tower fans.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H15 The initial conditions assume a basin temperature of 82°F with one SX pump running on each unit. This scenario assumes one tower cell (G) is out of service (OOS). Initially, no fans on all the other cells are running and all the bypass valves are closed. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 11 of ATD-0063, Rev. 413 [Ref. 4.4], with half of the RCFC heat load subtracted at 30 minutes. The flow parameters f, Q, M1, 131, M2, 132, a, and 0 are identical to Scenario 813 (Section 7.1.2), so they are not repeated here. The output from the MathCAD calculation for this scenario is shown on pages H100 through H106. The maximum basin temperature, Tbmax, is calculated to be 99.7°F with an initial basin temperature of 82°F. The temperature at 30 minutes is calculated to be 99.7°F with an initial basin temperature of 79°F. This value is below the acceptance limit of 100°F. 8.0 RESULTS AND CONCLUSIONS The results for Scenarios 8A, 8B, 8C, 8C1, 8C2, 8D, and 8D1 are summarized below. Table 8.1 - Summar~f of Scenarios - - - ' The single failure considered for all scenarios is the loss of power to Cells E and F. z These values are the current Technical Specifications. Per Assumption 3.2, all of the above scenarios were run with an initial basin temperature of 96°F, 90°F, or 80°F, however, this value was reduced for scenarios 813, 8C, 8C1, 8C2, Wet Bulb Initial Basin Basin Max Basin Scenario Cells OOS' Temperature Temperature Temperature Temperature of o f (OF) at 30 o minutes 8A None 82 96 2 98,3 98.6 at 26 min 813 G 82 96 2 101.4 101.5 at 28 min 8B G 82 91 99.6 99.6 at 30 min 8C A & G 82 90 2 101.5 101.6 at 36 min 8C A & G 82 84 99.1 99.9 at 46 min 8C1 G & H 76 90 2 101.9 101.9 at 33 min 8C1 G & H 76 84 99.2 99.7 at 40 min 8C2 A & B 82 90 2 101.1 101.3 at 36 min 8C2 A & B 82 85 99.1 99.8 at 44 min 8D A & G 82 80 2 100.4 100.7 at 40 min 8D A & G 82 77 98.8 99.7 at 48 min 8D1 G 82 82 99.7 99.7 at 30 min I CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H16 and 8D so that all of the calculated maximum basin temperatures are below the SX cooling tower basin design temperature of 100°F. For scenario 8A, the maximum basin temperature occurs prior to 30 minutes, therefore for this scenario (no fans initially OOS, 96°F initial basin temperature), RCFC heat load would not need to be shed at 30 minutes. In case 8D1 for the first 10.1 minutes with no heat load the basin temperature went from 82°F to 94.5°F which is an increase of 12.5°F. For all scenarios in this calculation, the inputs for basin mass and heat input are the same, thus the 12.5°F increase in temperature will be the same for all scenarios were no cooling is assumed during the first 10 minutes. Thus for an assumed initial basin temperature of 77°F the temperature at 10 minutes will be 89.5°F. In scenario 8C1 (76°F wet bulb, 2 fans OOS on same bus, fans initially on) the calculated temperature at 10.1 minutes is 89.9°F. The heat removal capability once the fans are started is the same so the results from scenario 8C1 will be bounding for the case where no fans are assumed running for 10 minutes with a starting basin temperature of 77°F. Limitations In summary, the Byron Technical Specification 3.7.9 (SR 3.7.9.2) [Ref. 4.5] will have to be changed as follows in order to account for these results. 1) Modify the initial basin temperature of 96°F with seven or more fans running to 91 °F, since scenario 8B is the bounding scenario with one fan OOS. 2) Modify the initial basin temperature of 90°F with less than seven fans running to 84°F, since scenarios 8C and 8C1 are the bounding scenarios with two fans OOS. 3) Modify the initial basin temperature of 80°F with no fans initially running to 77°F, since scenario 8D is the bounding scenarios with two fans OOS. Also, procedures would have to be changed so that in the situation when two fans are going to be taken OOS for maintenance on the same electrical breaker (Scenario 8C1), operators would have to check that the wet bulb temperature is 5 76°F. Results are valid only if half of the RCFC heat load on the accident unit is shed at, or prior to, 30 minutes. Procedures would have to be changed to implement this operator action.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H17 94 93 92 90 - a ~ 89 88 86 85- Figure H-1: Scenario 8A 90 100 110 120 130 140 150 Thot (°F) 8A Tower A, 7727 gpm, Twb 82°F - - - 8A Tower B, 7603 gpm, Twb 82°F / i / /

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H18 9 O V Figure H-2: Scenario 8B/8D1 90 100 110 120 130 140 150 160 Ttwc (°F)

CALCULATION NO.-NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H19 a 99 97 95 91 89 87 85 Figure H-3: Scenario 8C -8C Tower A, 10 158 gpm, Twb 82°F --8C Tower B, 10 162 gpm, Twb 82°F 90 100 110 120 130 140 150 160 T,i (`F)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H2O 105 100 95 85 80 75 Figure H-4: Scenario 8C1 90 100 110 120 130 140 150 160 Tnoc (°F) 8C1 Tower A, 9041 gpm, Twb 76°F ---8C1 Tower B, 12412 gpm, Twb 76°F i i i i I i i CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H21 105 100 90 85 80 Figure H-5: Scenario 8C2 8C2 Tower A, 12356 gpm, Twb 82°F - -8C2 Tower B, 8997 gpm, Twb 82°F 90 100 110 120 130 140 150 160 Tnoc ('F)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H22 99 97 - 91 89 87 Figure H-6: Scenario 8D -8D Tower A, 10157 gpm, Twb 82°F - - 8D Tower B, 10161 gpm, Twb 82°F 85 90 100 110 120 130 140 150 160 Tnot (0 F)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H: Scenario 8A Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with no Cells OOS ORIGIN=- t in=- 1 L lbm = I M F =- 1 Q sec --- 1 T gpm := g a l lbm-F MBTU := BTU-106 min Cooling Tower Performance Th 1 := (11119.8 2) -F Tcl:= (9819.0.8 90.79 Th2 := 118.79) -F Tc2:= -F 111.6 ~ 89.6 Th3 := -F 111.8 119.02) TO := -F 89.8 91.02) Th4 118.791 := C 111.lI6 -F Tc4 := -F 89.6 90.79)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H, Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2:= T2:_ min 823 . hr 19.98 804 21.65 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 386 732.17 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H SX System Flow rate Q l := 65076-gpm (Total flow to T1 and T2 gpm) Q2:= 65076.gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068-10 6. gal (Design input 2. 1) p := 8.33- Ibm Mb := p - V g a m C := I. BTU F- Ibm Fans (Active/Total) Time Constant fl l := 0.946 fl2:= 0.946 f21 := 0.517 f22 := 0.517 Mb = 8.9 x 10 6 1bm V V i 1 := - i2 := - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.502 (x2:= 0.502 (31 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 MI I := slope(ThI,Tcl)

BII := intercept(ThI,Tc1)

M12 := slope(Th3,Tc3)

B12 := intercept(Th3,Tc3)

M21 := slope(Th2,Tc2)

B21 := intercept(Th2,Tc2)

M22 := slope(Th4,Tc4)

B22 := intercept(Th4,Tc4)

MI l = 0.169 BI1 = 70.909F M12 = 0.169 B12 = 70.909F M21 = 0.166 B21 = 71.129 F M22 = 0.166 B22 = 71.129 F CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H, Calculate Intermediate Constants A 1 := A2 := ( v Q1) Q2 V D1 := P1-(1 - fl l + f11-M11) + (l - Mb. CP D2 := (32.(1 - fl2 + fl2-M12) + (1 - [32)-(1 - f22 + f22.M22) Mb. CP al fl l-B11 + (1 - al)421-B21 V a2-f12.B12 + (1 - a2).f22-B22 C2:= Q2. V Al = -0.04 1 min A2=-0.04 1 min Integrating to Solve for Basin Temperature D1 8 F = 4.28 x 10 F BTU C1 = 3.17 min F D2 =4.28x 10 8 F BTU C2 = 3.17 min - al-[(l - fl 1) + fl I-MIIj - (1 - a1) -(1 - f21 + f21-M21)] - a2-[(l - f12) + fl2-M12] - (1 - a2)-(1 - f22 + f22-M22)]

.= 96-F i := 1 .. 299 H:= .1 -min st. := i-H ub i+1 := Ubi + RA I-Ubil + (linterp(T2,L2,st) -Dl) + (C1)l-H use uprate heat load with operator action at t=30 minutes to reduce = 300..2400 la:= .1-min st i := i-H heat load use uprate heat load Ub i+1 := Ubi + C (A2.Ubi) + (1interp(T2,L2,st i)-D2) + (C2)l.H with operator action at t=30 minutes to reduce heat load (31)-(1 - f21 + f21.M21)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H Results 107 104.88 102.75 100.63 o Ubi 98.5 96.38 94.25 92.13 90 use uvrate heat load max(Ub) = 98.56 F @ t = 25.8 min = 98.3 F 3 0 2000 4000 6000 8000 1.10 4 1.2-10 4 St; Basin Temperature Response vs. Time (sec) 0 = 96.7 F maximum := maximum f-- 0 for i E 100.. 2400 maximum +- max(Ub i) if max(Ub i l >_ maximum index := index = 98.56 F st index = 1548 see index = 258 ,w=1,20-7000 maximum = 98.56 F index F- 0 maximum +- 0 for i E 100.. 2400 maximum F- max(Ub i) if max(Ub i l >_ maximum index <- i if maxx~Ub i) >_ maximum CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H2 Basin Temperature and UHS Heat Load vs. Time F linterp(T2, L2, st.) MBTU hr ;= 1,26.. 1000 st. min 96 83 0.1 96.22 713.29 2.6 96.43 680.85 5.1 96.58 658.04 7.6 96.69 639.21 10.1 96.96 922.62 12.6 97.47 888.28 15.1 97.87 853.49 17.6 98.18 821.63 20.1 98.42 793.76 22.6 98.55 716.78 25.1 98.52 619.56 27.6 98.32 526.1 30.1 98.04 507.35 32.6 97.76 488.6 35.1 97.47 469.85 37.6 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H Page H2! ,~= 1, 20.. 6000 1000 2000 3000 4000 5000 6000 A Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H31 Scenario 8B Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cell G COS ORIGIN =-- 1 in = 1L Ibm = 1MF = 1Q sec --- IT gpm := g a l ti i - Ibm-F MBTU := BTU-106 min Cooling Tower Performance Thl _ (1 1 1 1 2 9.54.86) .F Tcl :_ (90.54).F Th2:= (1 122 14.86.47) F TC2:= (92 94.86.47 ).F TO := -F 112.54 119.86) TO := .F 90.54 091.86) Th4 := -F 114.86 122.47) Tc4 := ( 94.47) 92.86) ) ~F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3 , Uorate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2 := T2 := min 823 hr 19.98 804 21.65 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 386 732.17 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3; SX System Flow rate Q l := 64945 . gpm (Total flow to T1 and T2 gpm) Q2:= 64945 . gpm (Total flow to Tt and T2 gpm) Basin Mass V:= 1.068-106.gal (Design input 2.11) p := 833 lbm Mb := p'V g a l BTU C p:= 1. F- ibm Fans (Active/Total) Time Constant f1 l := 0.948 fl2 := 0.948 f21 := 0.375 f22 := 0.375 Mb = 8.9 x 10 6 1bm V V il := - i2 := - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.531 a2:= 0.531 (31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tc1) B11 := intercept(Thl,Tcl) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22 := slope(Th4,Tc4) B22 := intercept(Th4,Tc4)

M11=0.18 B11=70.246F M12=0.18 B12=70.246F M21 = 0.212 B21 = 68.56 F M22 = 0.212 B22 = 68.56 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3: Calculate Intermediate Constants A 1 := _Q1) ~_ V ) -[1 - al.[(1 - ell) + f] 1-M11] - (1 - a1).(1 - f21 + f21-M21)]

A2 := (-2) -[1 - u2 j(1 - f12) + f12-M12] - (1 - a2)-(1 - f22 + M-M22)] D1 :_ (31-(1 - f11 + f11-M11) + (1 - pi)-(1 - f21 + f21.M21) M b-C p D2 : (32-(1 - e12 + f12-M12) + (1 - (32)-(1 - f22 + f22.M22) _ M b-C p Cl := Q1. al.f i l-B11 + (1 - al)421-B21 V Integrating to Solve for Basin Temperature

.= 96-F i+1 := Ubi+ [(A1-Ub) + (linterp(T2,L2,st i)-D1) + (C1)1.H = 300..2400 a:= .l-min st i r= i-H i+f := Ub i + [(A2-Ub i) + (linterp(T2,L2,st i)-D2) + (C2)l.H i := 1.. 299 H:= .l-min st. := i-H use uprate heat load with operator action at t=30 minutes to reduce heat load use uprate heat load with operator action at t=30 minutes to reduce heat load a2-f12-B12

+ - C2:= Q2- (1 V a2)-f22-B22 Al=-0.031 min F D1 =5.05x 10 8 BTU F C1=2.88 min A2 = -0.03 1 min F D2 8 = 5.05 x 10 BTU C2 F = 2.88 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3 , Results : 107 104.88 102.75 100.63 96.38 94.25 92.13 90 0 2000 4000 6000 8000 1.10 4 1.2-10 4 Sti use uerate heat load 3 max(Ub) = 101.51 F@ t = 27.7 min = 101.4 F Ub 100 = 98F ;= 1,20-7000 Basin Temperature Response vs. Time (sec) maximum := maximum <- 0 for i e 300.. 2400 maximum <- max(Ub) if max(Ub i l >_ maximum index := index = 101.51 F st. = 1662 see index index <- 0 maximum +- 0 for i E 100.. 2400 maximum = 101.42 F maximum +- max(Ub i l if max(Ub i) >_ maximum index <- i if maxx(Ub J.) _> maximum index = 277 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3! Basin Temperature and UHS Heat Load vs. Time F linterp(T2 , L2, st i) MBTU hr ;= 1,26.. 1000 st. i min 96 83 0.1 96.58 713.29 2.6 97.13 680.85 5.1 97.59 658.04 7.6 97.97 639.21 10.1 98.53 922.62 12.6 99.35 888.28 15.1 100.04 853.49 17.6 100.6 821.63 20.1 101.06 793.76 22.6 101.39 716.78 25.1 101.51 619.56 27.6 101.42 526.1 30.1 101.22 507.35 32.6 101 488.6 35.1 100.77 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H31 ,~.= 1,20.. 6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3' Scenario 8B Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss o£ power to Cells E and F) with Cell G OOS ORIGIN _ 1 in=- 1L lbm-= 1 M F - 1Q scc--_ 1 T gpm :=g a l ::= lbm-F MBTU := BTU-106 min Cooling Tower Performance

Th l := The := Th3 := Th4 := 119.86 112.54 122.47 C114.86 C 119.86) 112.54 122.47) -F Tc l := F Tc2:= -F -F Tc3 := Tc4 := 91.86 90.54 4.47 9 9 2.86) 91.86) 90.54 ( 94.47) -F -F -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H31 U_nrate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 386 MBTU hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H3! SX System Flow rate Q l := 64945.gpm (Total flow to T1 and T2 gpm) Q2:= 64945 . gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068 - 10 6. gal (Design input 2.1) p := 8.33. lbm Mb := p.V cp.= 1. BTU Mb = g_9 x 10 6 1bm gal F- lbm V Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.531 a2 := 0.531 (31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl) 1311 := intercept(Th1,Tcl) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) M11 = 0.18 B 11 = 70.246 F M12 = 0.18 B12 = 70.246F M21 = 0.212 B21 = 68.56 F M22 = 0.212 B22 = 68.56 F Fans (Active/Total)

Time Constant V fl 1 := 0.948 f12 := 0.948 Ql f2l := 0.375 122 := 0.375 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H41 Calculate Intermediate Constants 1 A 1 := - a1-[(I - fll) + f11.M11] - (1 - al).(1 - f21 + f2l.M21)] A2 := (-).C1 - a2.[(l - f12) + f12-M12] - (I - a,2)-(1 - f22+ M-M22)] Q D1 := R1-(1 - f11 + f11-M11) + (1 - (31)-(I - f21 + f21-M21) M b-C p D2 :_ (32-(1 - f12 + f12-M12) + (1 - p2).(1 - f22+ f22-M22) M b-C p Cl := Q1. a,1-f11-Bl l + (1 - al)421-B21 V Integrating to Solve for Basin Temperature

= 91-F i:= 1..299H:= .1-min St. := i-H i+1 := Ub i + [(AI-Ub i) + (linterp(T2,L2,st i)-D1) + (C1)1.H ;= 300-2400 1a:= .1-min St i-H + [(A2-Ubi)

+ (linterp(T2,L2,st i).D2) + (C2)l.H use uprate heat load with operator action at t=30 minutes to reduce heat load use uprate heat load with operator action at t=30 minutes to reduce heat load + - C2:= Q2. a2-f12-B12 (1 V a2)422-B22 A1=-0.03 1 min D1 =5.05x 10 8 F BTU C 1 = 2.88 F min _ -0.03 1 min D2 = 5.05 x 10 8 F BTU C2 = 2.88 F - min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4 Results 107 104.88 102.75 100.63 Ubi 98.5 96.38 94.25 92.13 90 0 use uprate heat load max(Ub) = 99.59 F @ t = 30.0 min Ub 300 = 99.6 F = 94.4 F index := index = 99.59 F St index inde x= 1800 sec ex 1,20..7000 2000 4000 6000 8000 1-10 4 1.2-10 4 Sti Basin Temperature Response vs. Time (sec) maximum := maximum f- 0 for i e 300.. 2400 maximum <- max(Ub., if max( index F- 0 maximum f- 0 for i c 300.. 2400 I maximum +- max(Ub i) if max(Ub i l >_ maximum index F- i if max(Ub i) >_ maximum index = 300 i) ? maximum maximum= 99.59 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4; Basin Temperature and UHS Heat Load vs. Time Ub. F linterp(T2, L2, st i) MBTU hr ~= 1,26.. 1000 St. min 91 83 0.1 91.98 713.29 2.6 92.91 680.85 5.1 93.71 658.04 7.6 94.4 639.21 10.1 95.24 922.62 12.6 96.33 888.28 15.1 97.26 853.49 17.6 98.05 821.63 20.1 98.71 793.76 22.6 99.23 716.78 25.1 99.52 619.56 27.6 99.59 526.1 30.1 99.54 507.35 32.6 99.46 488.6 35.1 99.35 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4 M;= 1, 20.. 6000 1000 2000 3000 4000 5000 6000 st; Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4 Scenario 8C Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN - 1 in =- I L Ibm = IM F = 1 Q sec =-- 1 T gpm := g a l Ibm-F MBTU := BTU-106 min Cooling Tower Performance

(123.81) Th l := ~ 116.07 95.81 Tc 1 := ( 94.07 Th2 := 0116.08) 123.82) -F Tc2:_ 95.821 -F 94.08 123.8 Th3 :_ (1161.07).F TO :_ (9495.81.07))._ Th4:= (1 123 16.08.82) .' Tc4:= (94.08)

CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4 Ugrate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 386 MBTU hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17) min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H41 SX System Flow rate QI := 64771 -gpm (Total flow to T1 and T2 gpm) Q2:= 64771. gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.06810 6. gal (Design input 2.1) Ibm p := 8.331 g a l Mb:= p-V C p := 1. BTU F- Ibm Fans (Active/Total) Time Constant fl l := 0.943 n2:= 0.943 f21 := 0.376 f22 := 0.376 Mb = 8.9 x 10 6 1bm Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.499 a2 := 0.499 (31 := 0.53 p2 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl) 1311 := intercept(Th1,Tc1) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 = intercept(Th4, Tc4) M1 1 = 0.225 B 11 = 67.977 F M12 = 0.225 B 12 = 67.977 F M21 = 0.225 B21 = 67.984 F M22 = 0.225 B22 = 67.984 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4' Calculate Intermediate Constants A l := A2:= C-Q 1~ __Q2~ V .[1 - al.[(l - f11) + f11-M11] - (l - al)-(1 - f2l + f21-M21)]

-[1 - a2.[(l - f12) + f12M12] - (1 - (x2).(l - f22 + f22-M22)]

D1 :_ R1-(1 - f11 + f11-M11) + (1 - Rl)-(1 - f2l + f2l-M21) M b-C p D2 := (32-(1 - f12 + f12-M12) + (1 - R2)-(1 - f22 + f22-M22) Mb. Cp Cl := Q1. al'f11-B11 + (1 - al)421-B21 V C2:= Q2. a 2-f12.B12+ (1 - a2).f22.B22 V Al=-0.03 1 D1 =5.35x 10 8 F min BTU A2 = -0.03 1 D2 = 5.35 x 10 8 F C2 - 2.72 F min BTU Integrating to Solve for Basin Temperature

= 90-F i:= 1..299H:= .1 -min st. := i-H i Ub Ub i + [(AI-Ub i) + (Iinterp(T2,L2,st i)-D1) + (C1)].H = 300-2400 Fa:= A-min A i := i-H Ub i+1 := Ubi + [(A2.Ub i) + (linterp(T2,L2,st i).D2) + (C2)]-H Cl = 2.72 F min min use uprate heat load with operator action at t=30 minutes to reduce heat load use uprate heat load with operator action at t=30 minutes to reduce heat load CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H41 Results 107 104.88 102.75 100.63 o Ubi 98.5 96.38 94.25 92.13 90 Ub 100 = 94.5 F ~= 1,20.. 7000 0 2000 4000 6000 8000 1.10 4 1.2-10 4 9ti 3 ,.,. = 101.5 F Basin Temperature Response vs. Time (sec) use uprate heat load maximum:= maximum <- 0 for i E 300.. 2400 max(Ub) = 101.58 F@ t = 35.9 min maximum t- max(Ub i) if ma index := index = 101.58F St. = 2154 sec index maximum= 101.58F index F- 0 maximum F- 0 for i e 300.. 2400 i) >_ maximum maximum f- max(Ub i l if max~Ub i l >_ maximum index <- i if max~Ub/i) > maximum index = 359 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H4! Basin Temperature and UHS Heat Load vs. Time Ub i F linterp(T2, L2, \stil IvfBTU hr ~= 1,26.. 1000 St. min 90 83 0.1 91.3 713.29 2.6 92.52 680.85 5.1 93.6 658.04 7.6 94.55 639.21 10.1 95.65 922.62 12.6 97 888.28 15.1 98.18 853.49 17.6 99.19 821.63 20.1 100.07 793.76 22.6 100.78 716.78 25.1 101.24 619.56 27.6 101.46 526.1 30.1 101.54 507.35 32.6 101.58 488.6 35.1 101.57 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H51 ,~;= 1,20-6000 1000 2000 3000 4000 5000 6000 St; Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5 , Scenario 8C Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN=- l in =-- 1 L Ibm --- 1M F-- 1 Q sec=- 1 T gpm := g a l := lbm-F MBTU := BTU-106 Cooling Tower Performance Thl :_ 123.81 (116.07).' Tc1 _ (9495.81.07))._ mm Th2 := 116.08 123.82)-F Tc2:= -F 94.08 (95.82) 123.81 95.81 Th3:= (116.07)-F Tc3:= -F 94.07 123.82 95.82) Th4:= (116.08). F Tc4:= 0 94.08) ) -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5, Uprate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 386 MBTU hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5 SX System Flow rate Q 1 := 64771 . gpm (Total flow to Tl and T2 gpm) Q2:= 64771-gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068-10. gal (Design input 2.1) p:= 8.33. lbm Mb := P' V C p = 1. BTU Mb = 8.9 x 10 6 1bm gal F- lbm Fans (Active/Total) Time Constant fl I:= 0.943 f]2:= 0.943 f21 := 0.376 f22 := 0.376 V V '11 := - T2 := - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.499 a2 := 0.499 (31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Th l , Tc l) 1311 := intercept(Th 1, Tc 1) M12 := slope(Th3 ,Tc3) B12 := intercept(Th3 ,Tc3) M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) M11 = 0.225 B 11 = 67.977 F M12 = 0.225 B 12 = 67.977 F M21 = 0.225 B21 = 67.984F M22 = 0.225 B22 = 67.984 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5 , Calculate Intermediate Constants Al :_ -Q 1~ ~1 - al-[(1 - fl l) + fl 1-M11] - (1 - al)-(1 - f2l + f21-M21)]

A2:= .[I - a2-[(1 - f12) + f12M12] - (l - a2)-(l - f22 + f22.M22)] D1;= fll+fl1-M11)+(1-(31-(1-f21+f21.M21) M b' C P D2 := (32.(l - f12+ fl2M12) + (l - [32).(l - f22+ f22-M22) M b'C P a1 411-B11 + (1 - a0421-B21 C1 := Q1- V C2:= Qz- a 2-fl2-B12

+ (I - a2)422-B22 Integrating to Solve for Basin Temperature 84-F i := 1 ..299 H:= .I-min st. i-H i+1 '- Ubi+ [(A1.Ubi) + (linterp(T2,L2,st i)-D1) + (Cl)l.H = 300.. 2400 U:= .l-min st i:= i-H Ubi+1 := Ubi + [(A2.Ubi) + (linterp(T2,L2,st i).D2) + (C2)1.H C 1 = 2.72 F min C2 = 2.72 F min use uprate heat load with operator action at t=30 minutes to reduce heat load use uprause uprate heat load with operator action at t=30 minutes to reduce heat loadte heat load Al=-0.03 1 D1 =5.35x 10 8 min BTU A2 = -0.03 1 min F D2 8 = 5.35 x 10 BTU CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5! Results 107 104.88 102.75 100.63 Ubi 98.5 96.38 94.25 92.13 90 Ub 300 - 99.1 F Ub 100 = 90.1 F 1,20..7000 0 2000 4000 6000 8000 1.10 4 1.2-10 4 St; Basin Temperature Response vs. Time (sec) use uprate heat load maximum:= maximum E- 0 for i E 300., 2400 max(Ub) = 99.87 F @ t = 46.2 min maximum E- max(Ub i) if max(Ub J >_ maximum index := index = 99.87 F st. index = 2772 sec maximum = 99.87 F index +- 0 maximum F- 0 for i E 300.. 2400 maximum E-- max(Ub i) if max(Ub i) >_ maximum index +- i if max(Ub i) > maximum index = 462 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5 Basin Temperature and UHS Heat Load vs. Time F linterp(T2 , L2, st) MB TU hr ~= 1,26.. 1000 St i min 84 83 0.1 85.74 713.29 2.6 87.38 680.85 5.1 88.84 658.04 7.6 90.15 639.21 10.1 91.58 922.62 12.6 93.23 888.28 15.1 94.69 853.49 17.6 95.97 821.63 20.1 97.08 793.76 22.6 98.02 716.78 25.1 98.69 619.56 27.6 99.09 526.1 30.1 99.35 507.35 32.6 99.55 488.6 35.1 99.7 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H57 ,~= 1, 20.. 6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5 Scenario 8C1 Two Tower Model - (Heat load for Power IIprate) Breaker Failure (Loss of power to Cells E and F) with Cells G and H OOS ORIGIN= 1 in=- 1L lbm =-- 1MF =- 1Q sec=- 1T gpm := g a l Ibm-F MBTU := BTU-106 min Cooling Tower Performance Thl :_ (1 118 10..32 12) .F Tcl _ (88 90..32 12 ).F Th2 := Th3 := Th4 := 126.16 117.6 0 118.12 (110.32) 126.161 117.l I 6 -F -F -F Tc2 := Tc3 := Tc4 := 98.16 95.6 90.12 (88.32 0 98.16) 95.6 -F -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H5! Ugrate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 386 MB T U hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H& SX System Flow rate Q 1 := 64676 gpm (Total flow to Tt and T2 gpm) Q2:= 64676 , gpm (Total flow to TI and T2 gpm) Basin Mass V := L068-10 6. gal (Design input 2. 1) x 10 6 1bm V Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.587 a2:= 0.587 /31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 Mll := slope(Th1,Tc1) 1311 = intercept(Th1,Tc1) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22:= intercept(Th4, Tc4) M11 = 0.231 B11 = 62.862F M12 = 0.231 B12 = 62.862F M21 = 0.299 B21 = 60.43 F M22 = 0.299 B22 = 60.43 F lbm p:= 8.33. gal Fans Mb := p - V cp.= (Active/Total)

BTU I _ = 8.9 F- Ibm Mb Time Constant V fl 1 := 0.953 f]2:= 0.953 Ql f21 := 0.093 f22:= 0.093 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6 Calculate Intermediate Constants A 1 := A2:= (-2 V 1))-[1 -al.[(1-fl1)+fl1-M]

1]-(1-al)-(1-f21+f21M21)]

(-Q).[1 - a2.[(l - f12) + fl2-M12] - (1 - c2).(1 - f22 + f22-M22)]

D1:=(31"(1-fll+fl1-M11)+(1-RI)-(1-f21+f21.M21) M b-C p D2:= (32'(1 - f12 + f12-M12) + (1 - /32)-(l - f22 + f22-M22) M b-C p Cl := Q1. al-fl1-B11

+ (1 - al)421-B21 V Integrating to Solve for Basin Temperature

= 90-F i:= 1..299H:= .l-min st. := i-H i Ub i+1 := Ubi + [(A1.Ubi) + (linterp(T2,L2,st i) -D1) + (C1)]-H = 300.. 2400 2L:= .1 -min st i := i-H Ub i+l := Ubi+ [(A2.Ub) + (linterp(T2,L2,st i).D2) + (C2)].H use uprate heat load with operator action at t=30 minutes to reduce heat load use uprate heat load with operator action at t=30 minutes to reduce heat load a2-f1 2-B12 + (1 - a2)422-B22 C2:= Q2. V A1=-0.03 1 D1 =6.53x 10 8 F F min BTU C1=. 227 min 1 8 F A2 = -0.03 D2 = 6.53 x 10 F min BTU C2 = 2.27 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6; Results 109 106.63 104.25 101.88 o Ub; 99.5 97.13 94.75 92.38 90 use ugrate heat load 0 2000 4000 6000 8000 1.10 4 1.2-10 4 A Basin Temperature Response vs. Time (sec) max(Ub) = 101.89 F@ t = 32.8 min 300 = 101.9 F = 94.4 F index := index = 101.89F St index = 1968 see ~= 1,20.. 7000 maximum := maximum +- 0 for i E 300.. 2400 maximum F- max(Ub i' if max(Ub i l >_ maximum maximum= 101.89F index E-- 0 maximum E- 0 for i E 300.. 2400 I maximum +- max(Ub) if max(Ub i) >_ maximum index E- i if max(Ub i) >_ maximum index = 328 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6: Basin Temperature and UHS Heat Load vs. Time Ub. F linterp(T2, L2, st.l l 1vfBTU hr ,~= 1, 26.. 1000 st i min 90 83 0.1 91.26 713.29 2.6 92.47 680.85 5.1 93.53 658.04 7.6 94.47 639.21 10.1 95.61 922.62 12.6 97.08 888.28 15.1 98.36 853.49 17.6 99.47 821.63 20.1 100.42 793.76 22.6 101.2 716.78 25.1 101.67 619.56 27.6 101.86 526.1 30.1 101.89 507.35 32.6 101.87 488.6 35.1 101.8 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6. 1000 800 600 linter~T2, L2, st;) MBTU) hr 400 200 ,z,;= 1, 20.. 6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6 Scenario SC1 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells G and H COS ORIGIN = t in= 1 L Ibm =-- I M F = 1 Q sec --= 1 T gpm :=g a l := Ibm-F MBTU := BTU-106 min Cooling Tower Performance

Thl :_ (110.32) .F Tcl :_ (88 90..32 12 ).F Th2 := ( 1 117 5 ) -F Tc2:= (98.16 )-F 118.12 Th3:= (110.32). F 90.12 TO:= 088.32) -F Th4:= ( . F 117.6 126.16) Tc4:= -F 95.6 098.16 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6 Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2 := T2 := min 823 hr 19.98 804 21.65 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 1 386, 732.17 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6' SX System Flow rate Q l := 64676-gpm (Total flow to TI and T2 gpm) Q2:= 64676. gpm (Total flow to Tt and T2 gpm) Basin Mass V := 1.068.10 6. gal (design input 2.1) p := 8.33. Ibm Mb := P- V C p := 1 . BTU Mb = 8.9 x 10 6 1bm gal F-Ibm Fans (Active/Total) Time Constant fl I:= 0.953 fl2 := 0.953 f21 := 0.093 f22 := 0.093 V V 'Cl := - ti2 := - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.587 (x2:= 0.587 /31 := 0.53 X32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 Ml I := slope(Th1,Tc1) 1311 := intercept(ThI,Tcl) M12 := slope(Th3,Tc3) B12:= intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) M I 1 = 0.231 1311 = 62.862F M12 = 0.231 B 12 = 62.862 F M21 = 0.299 B21 = 60.43 F M22 = 0.299 B22 = 60.43 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6 Calculate Intermediate Constants A1:_ -Q 11.[1-al[(1-fll)+f11M11]-(1-al)(1-f21+f2

.1M21)] A2:= .[1 - a2.[(1 - f12) + f12-M12] - (1 - a2).(l - f22+ f22.M22)] DI;= Q1.(1-fll+f11-M11)+(1-(31)

.(1-f2l+f21-M21)

M b-C p D2 :_ (32.(1 - f12 + f12-M12) + (1 - [32).(1 - f22 + f22-M22) M b-C p al -fl 1-B11 + (1 - al)-f21-B21 Integrating to Solve for Basin Temperature

.= 84-F i:= 1..299H:= .1-min st. := i - H i+1 := Ub i+ [(A1-Ub i) + (linterp(T2,L2,st i)-DI) + (C1)].H ;= 300.. 2400 I:= .1 - min st i := i - H Ub i+1 := Ubi+ [(A2.Ubi) + (linterp(T2,L2,st i).D2) + (C2)].H use uprate heat load with operator action at t=30 minutes to reduce heat load use uprate heat load with operator action at t=30 minutes to reduce heat load C2:= Q2. a2-f12-B12

+ V (1 - a2)421B22 V 1 8 F Al=-0.03 D1 =6.53x 10 F min BTU C1=. 227 min 1 8 F A2 = -0.03 D2 = 6.53 x 10 F min BTU C2 = 2.27 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H6! Results 109 106.63 104.25 101.88 o Ubi 99.5 97.13 94.75 92.38 90 0 2000 4000 6000 8000 1.10 4 1.2-10 4 St; use uprate heat load max(Ub) = 99.71 F @ t = 40.3 min 300 - 99.2 F 0 = 89.9F Basin Temperature Response vs. Time (sec) index = 99.71 F maximum := maximum t- 0 for i c 300.. 2400 maximum F- max(Ub.l /i index := St index = 2418 sec ;= 1, 20.. 7000 index <- 0 maximum +- 0 for i c 300.. 2400 if ma maximum = 99.71 F maximum F- max~Ub.l if max( ,i index +- i if max(Ub.) >_ maximum i) >_ maximum i) >_ maximum index = 403 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H70 Basin Temperature and UHS Heat Load vs. Time Ub. F linterp(T2, L2, st) MBTU hr 1,26..1000 st d min 84 83 0.1 85.66 713.29 2.6 87.25 680.85 5.1 88.66 658.04 7.6 89.92 639.21 10.1 91.36 922.62 12.6 93.12 888.28 15.1 94.67 853.49 17.6 96.02 821.63 20.1 97.21 793.76 22.6 98.2 716.78 25.1 98.88 619.56 27.6 99.25 526.1 30.1 99.45 507.35 32.6 99.6 488.6 35.1 99.68 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H71 1000 800 600 fnter~T2, L2, sti) MBTU) hr 400 200 ,~;= 1,20.. 6000 1000 2000 3000 4000 5000 6000 st i Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H72 Scenario 8C2 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN = 1 in _ 1L Ibm - 1MF =-- 1Q sec =-- 1T gpm := g a l 2jL:= Ibm-F MBTU := BTU-106 min Cooling Tower Performance 120.45 98.451 Th 1 := -F Tel := -F 111.59 `95.59) 121.441 (93.44 Th2 := .F Tc2:= -F 113.95 JI `91.95 120.45) Th3 := I -F Tc3 := 98,45) -F 111.59/ Th4 := (113.95) 121.441, -F Tc4 := ~ 93.44) -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H73 L2 := Uz2rate Heat load 1L42) 83 0.00 83 0.17 i j 769 0.35 760 0.50 749 0.75 724 2.00 I 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 1 652 8.32 I j 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 I 866 16.65 844 MBTU 18.32 T2:_ min 823 hr 19.98 804 21.65 i 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 386 732.17 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H74 SX System Flow rate Q l := 64644. gpm (Total flow to T1 and T2 gpm) Q2:= 64644. gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068-10 6. gal (Design input 2.1) P:= 8.33. lbm Mb := P- V Cp := l . BTU Mb = 8.9 x 10 6 1bm gal F- lbm Fans (Active/Total) Time Constant fl l := 0.928 f12 := 0.928 f21 := 0.521 f22 := 0.521 V i1 :_ V - 1;2 :_ - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.412 a2:= 0.412 (31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Th1,Tcl) B11 := intercept(Th1,Tcl) M12 = slope(Th3,Tc3) B12:= intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22:= slope(Th4,Tc4) B22:= intercept(Th4,Tc4)

M11 = 0.323 B11 = 59.569F M12 = 0.323 B12 = 59.569F M21 = 0.199 B21 = 69.282 F M22 = 0.199 B22 = 69.282 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H75 Calculate Intermediate Constants A1:= -Q 1 -[1-alJ(1-flI)+fl1M11]-(1-al)

.(I-12l+f21M21)]

V ) A2:= .[1 - a2-[(1 - f12) + f12-M12] - (1 - a2)-(1 - f22 + f22.M22)] DI (31.(1 - f1 l + fl 1.M11) + (1 - pi)-(l - f21 + f21-M21) :_ M b'C P D2 := p2.(1 - f12 + fl2.M12) + (1 - p2).(1 - f22 + f22.M22) M b'C P C1 := Q1 al-f11.B11 + (1 - al)-f21-B21

~ Integrating to Solve for Basin Temperature

+ C2:= - Q2 a2-fl2-B12 V (1 - a2)422-B22 V Al=-0.03 I D1 =5.29x 10 8 F min BTU C 1 = 2.66 min 1 8 F -0.03 D2 = 5.29 x 10 F min BTU C2 = 2.66 - min Ub I := 90-F i:= 1..299H:= .1-min st i := i-H Ub i+1 '-+ RA I-Ub i l + (linterp(T2,L2,st i)-D1) + (C1)]-H use uprate heat load with operator action at t=30 minutes to reduce i ~= 300..2400 1-min st.:= i-H heat load + [(A2.Ub i) + (linterp(T2,L2,st i)-D2) + (C2)].H use uprate heat load with operator action at t=30 minutes to reduce heat load CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H76 Results 107 104.88 102.75 100.63 Ubi 98.5 96.38 94.25 92.13 90 use uprate heat load maximum:= maximum <- 0 for i c 300.. 2400 max(Ub) = 101.26 F@ t = 35.6 min maximum <- max(Ub i) if max(Ub.) >_ maximum li Ub 300 = 101.1 F = 94.4 F maximum= 101.26F 0 2000 4000 6000 8000 1.10 4 1.2-10 4 st i Basin Temperature Response vs. Time (sec) index = 101.26F index := st index = 2136 see M;= 1,20..7000 index <- 0 maximum <- 0 for i e 300.. 2400 1 maximum <-- max(Ub i) if max(Ub i) >_ maximum index <- i if max(Ub.) ? maximum index = 356 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H7"A Basin Temperature and UHS Heat Load vs. Time Ub. F linterp(T2 , L2, st.) MBTU hr ~= 1,26.. 1000 St. i min 90 83 0.1 91.25 713.29 2.6 92.44 680.85 5.1 93.48 658.04 7.6 94.4 639.21 10.1 95.47 922.62 12.6 96.79 888.28 15.1 97.94 853.49 17.6 98.93 821.63 20.1 99.79 793.76 22.6 100.49 716.78 25.1 100.94 619.56 27.6 101.15 526.1 30.1 101.22 507.35 32.6 101.25 488.6 35.1 101.24 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H71 ,~= 1,20.. 6000 1000 2000 3000 4000 5000 6000 A Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H, Scenario 8C2 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN --- t in=- 1 L lbm = 1 M F =--- 1 Q see=- 1T gpm := g a l UJ := Ibm-F MBTU := BTU-106 min Cooling Tower Performance 120.45 Th l := F 111.59 Tcl := 98.45 (95.59 -F (121.44 93.44 Th2 := F Tc2:= -F (113.95) 91.95 Th3 := 120,45) -F Tc3 := 98.45) 121.44 93.44 Th4 := -F Tc4 := ~F 113.95 91.95 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page HE L2 := Unrate Heat load (L42) 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 MBTU 823 hr 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 ,386 T2 := 1 0.17 1 1 1 1 2.5 1 2.0 2.17 2.33 3.32 4.98 6.65 8.32 9.98 1 11.65 13.32 .." 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 .." 83.32 .. ":1 11 1 11 .11 11 . 1 ..1 11 ..1 11 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page F SX System Flow rate Q 1 := 64644 gpm (Total flow to T1 and T2 gpm) Q2:= 64644 " gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068- 10 6. gal (Design input 2.1) p := 8.33 ~ lbm g al Mb := p ' V C P := 1. BTU F lbm Fans (Active/Total) Time Constant fl l := 0.928 fl2 := 0.928 f21 := 0.521 t22:= 0.521 Mb = 8.9 x 10 6 1bm TI :_ V -- tit :_ V . Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.412 0 := 0.412 /31 := 0.53 /32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl) 1311 := intercept(Th1,Tcl) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22 := slope(Th4,Tc4) B22:= intercept(Th4,Tc4)

MI 1 = 0.323 B I 1 = 59.569 F M12 = 0.323 B 12 = 59.569 F M21 = 0.199 B21 = 69.282 F M22 = 0.199 B22 = 69.282 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H8: Calculate Intermediate Constants A1 .--- -cc I J(1 - fl I)+ fl I-M11) -(I - al)-(1 - f21 + f21-M21)]

A2 := (_Q2 V) .[I - a2-[(1 - f12) + fl2-M12] - (l - a2)-(l - f22 + f22-M22)]

D1 := X31'(1 - fl] + f11.M11) + (1 - pl)-(1 - f21 + f21-M21) M b' C P D2 := (32.(1 - fl2 + fl2M12) + (1 - R2)-(l - f22 + f22-M22) M b' C P Cl := Q1. al-f11-B11

+ (I - a0421-B21 V C2:= Q2. a2'fl2.Bl2 + (1 - a2)-f22-B22 V Al = -0.03 1 min A2 = -0.03 1 min Integrating to Solve for Basin Temperature

= 85-F i:= 1..299H:= .l-min st. := i-H i Ub i+1 '= Ubi + [(A1-Ub i) + (linterp(T2,L2,st i)-D1) + (C I)1-H with operator use heat load action at t=30 minutes to reduce heat load = 300..2400 a:= .1 -min st i := i-H I) + (Iinterp(T2,L2,st i).D2) + (C2)1.H use uprate heat load with operator action at t=30 minutes to reduce heat load D1 8 F = 5.29 x 10 F BTU C1 = 2.66 min D2 8 F = 5.29 x 10 F BTU C2 = 2.66 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H Results 107 104.88 102.75 100.63 o Ubi 98.5 96.38 94.25 92.13 ,~= 1, 20.. 7000 90 0 2000 4000 6000 8000 110 4 1.2-10 4 st; Basin Temperature Response vs. Time (sec) use uprate heat load maximum:= maximum <- 0 for i e 300-2400 max(Ub) = 99.76 F @ t = 44.2 min maximum E- maxtUb i l if max~Ub i' ? maximum 300 = 99.1 / ` lF Ub 100 = 90.7 F maximum = 99.76 F index := index = 99.76 F st. = 2652 see index index <- 0 maximum <-- 0 for i E 300.. 2400 maximum <-- max(Ub i) if max(Ub i) >maximum index F- i if max(Ub ii) >maximu m index = 442 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page Basin Temperature and UHS Heat Load vs. Time Ub i F linterp(T2, L2, st.l t / MBTU hr ,~= 1,26.. 1000 _ St i min 85 83 0.1 86.62 713.29 2.6 88.14 680.85 5.1 89.5 658.04 7.6 90.71 639.21 10.1 92.06 922.62 12.6 93.63 888.28 15.1 95.01 853.49 17.6 96.22 821.63 20.1 97.28 793.76 22.6 98.16 716.78 25.1 98.78 619.56 27.6 99.15 526.1 30.1 99.37 507.35 32.6 99.54 488.6 35.1 99.65 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page 4.= 1,20..6000 1000 2000 3000 4000 5000 6000 st l Post LOGA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page I Scenario 8D Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN=- tin= 1L Ibm = 1MF = 1Q sec --= 1T gpm := gal = lbm-F MBTU := BTU-106 min Cooling Tower Performance

123.81 95.81 Th 1 :_ -F Tc l := -F 116.07 94.07 123.82 )-F `95.82 Th2 := Tc2 := .F `116.07) X94.07 95.81 Th3 := 123.81) .F Tc3 := (~ F 94.07 123.82 Th4 := -F 116.07 Tc4 := 94.07) 95.82) -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page I Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2 := T2 := min 823 hr 19.98 804 21.65 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 1 386, 732.17 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H SX System Flow rate Q 1 := 64768 . gpm (Total flow to TI and T2 gpm) Q2:= 64768 . gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068.10 6. gal (Design input 2.1) p := 8.33. Ibm Mb ._ P.V Cp:= I. BTU Mb = 8-9 x 10 6 1bm gal F- lbm Fans (Active/Total) Time Constant fl l := 0.943 f12 := 0.943 f21 := 0.376 f22 := 0.376 V V T 1 := - T2:= - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.499 a2 := 0.499 01 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 Mll := slope(Thl,Tcl) 1311 := intercept(Thl,Tcl) M12:= slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) Ml 1 = 0.225 B I 1 = 67.977 F M12 = 0.225 B 12 = 67.977 F M21 = 0.226 B21 = 67.861 F M22 = 0.226 B22 = 67.861 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page 1 - Calculate Intermediate Constants Al := (-Q 1).[1 - al.[(1 - f11) + f11-M11] - (1 - al)-(1 - f21 + f21-M21)]

A2 := ~ v Q21 i+l '= Ubi + D - a2.[(l - f12) + f12-M12] - (1 - a2)-(1 - f22 + f22.M22)] DI :_ X31-(1 - f11 + fI1.M11) + (1 - [31).(I -121 + f2l.M21) Mb. Cp D2 := [32-(1 - f12 + f12-M12) + (I - /32).(l - f22 + f22-M22) M b-C p CI := Q1 a1-f11-Bl l + (1 - al)-f21-B21 V F C1=2.72 Integrating to Solve for Basin Temperature Ub 1 := 80-F i:= 1-99 H:= .l-min St i := i-H Iinterp(T2 , L2, st i) ~H M b-C p = 100-299 IU:= .1 -min st i := i-H Ub i+1 . := Ub i + [(AI-Ub i) + (linterp(T2,L2,st

,.)-D1) + (C1)l-H use uprate heat load with operator action at t=30 minutes to reduce heat load i ~= 300..2400 ~Nv~'- A -min -min St := i-H nN i+1 '= Ubi + C (A2-Ub i) + (linterp(T2,L2,st i) -D2) + (C2)].H min C2 = 2.72 F min use uprate heat load with operator action at t=30 minutes to reduce heat load + - C2:= Q2. a2-f12-B12 (1 V a2)-f22-B22 1 8 F Al=-0.03 D1=5.35x10 min BTU -0.031 8 F A2 = D2 = 5.35 x 10 min BTU CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H Results 107 103 99 95 87 83 79 75 0 2000 4000 6000 8000 110 4 1.210 4 sti use unrate heat load maximum := maximum E- 0 for i E 300.. 2400 max(Ub) = 100.74 F @ t = 39.8 min maximum +- max~Ub i l if ma x~Ub i l >_ maximum 3.. = 100.4 ` / ` JF Basin Temperature Response vs. Time (sec) Ub 100 = 92.5 F maximum= 100.74 F index := Ub index = 100.74 F st index = 2388 sec ~= 1,20-7000 index <-- 0 maximum E-- 0 for i E 300.. 2400 maximum +- max(Ub i , if max~ index <- i if maxx~Ub i J) ? maximum > maximum index = 398 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H Basin Temperature and UHS Heat Load vs. Time Ub. F 1 interp( T2 , L2, st) MBT U hr ;= 1,26..1000 st i min 80 83 0.1 83.19 713.29 2.6 86.46 680.85 5.1 89.59 658.04 7.6 92.55 639.21 10.1 93.8 922.62 12.6 95.29 888.28 15.1 96.59 853.49 17.6 97.73 821.63 20.1 98.71 793.76 22.6 99.53 716.78 25.1 100.08 619.56 27.6 100.39 526.1 30.1 100.55 507.35 32.6 100.66 488.6 35.1 100.72 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H9 ,~= 1,20-6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H9 Scenario 8D Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN -= t in=- 1 L lbm --- 1M F =-- 1 Q sec =-- 1 T gpm := g a l A J := 1bm-F MBTU := BTU-106 min Cooling Tower Performance 123.81 Th 1 := -F 116.07 95.81 Tcl:= (94.07) . F 123.82 95.82) Th2 := (116.07) Tc2 := -F 123.81 95.81) Th3:= (116.07) F Tc3:= ) -F 123.82 95.82) Th4:= (116.07). F Tc4:= ( 94.07) ) -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page I-Ujorate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 527 452 406 385 330 293 212 181 178 487 481 476 474 471 411 406 1 386, MBTU hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H SX System Flow rate Q l := 64768. gpm (Total flow to TI and T2 gpm) Q2:= 64768 . gpm (Total flow to TI and T2 gpm) Basin Mass V := 1.068-10 6. gal (Design input 2. 1) P := 8.33. Ibm Mb _= P' V cp.= I. BTU Mb = 8.9 x 10 6 1bm gal F- Ibm V ti2:=-Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.499 a2 := 0.499 01 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl) 1311 := intercept(Th1,Tc1) M12 slope(Th3,Tc3) B12:= intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22:= slope(Th4,Tc4) B22:= intercept(Th4,Tc4)

M11 = 0.225 B11 = 67.977F M12 = 0.225 B12 = 67.977F M21 = 0.226 B21 = 67.861 F M22 = 0.226 B22 = 67.861 F Fans (Active/Total)

Time Constant V fl 1 := 0.943 f]2:= 0.943 TI :=- Q1 f21 := 0.376 f22 := 0.376 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page W Calculate Intermediate Constants Al :_ -I J-[I - al.[(1 - fll) + fl I.M11] - (1 - al)-(1 - f21 + f21.M21)] C1 := QI- al-f-Bl l + (1 - al)-f21-B21 V Integrating to Solve for Basin Temperature i:= L.99 H:= .1-min linterp(T2, L2, st.) Ub i+1 := Ub i + Mb-CP ,H A2 := DI := R1.(I - f1 l + fl 1-M11) + (1 - 01).(1 - f21 + f21.M21) D2:= R2-(l - fl2 + fl2-M12) + (1 - /32)-(I - f22 + f22.M22) = 100.. 299 Ia:= .1-min st i := i-H uprate i+1 := Ubi+ [(Al-Ub i) + (linterp(T2,L2,st i)-D1) + (CI)].H wiuse_ th o ra orpera heat load tor action at t=30 minutes to reduce heat load = 300.. 2400 IU:= .1-min st i := i-H (_22) .= 77-F .[I - a2j(I - f12) + fl2-M12] - (I - (x2)-(1 - f22+ f22.M22)] M b-C P M b-C P st. := i-H i + [(A2.Ub i) + (linterp(T2,L2,st i)-D2) + (C2)]-H use uprate heat load with operator action at t=30 minutes to reduce heat load + - C2:= Q2. a2-fl2-B12 (1 V a2)422-B22 Al=-0.031 min D1 =5.35x 10 8 F BTU C1 F = 2.72 min A2=-0.03 1 min D2 =535x 10 8 F BTU C2 F = 2.72 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H<, Results 107 103 99 95 o Ub; 91 87 83 79 75 use uprate heat load maximum:= maximum f- 0 for i c 300.. 2400 max(Ub) = 99.68 F @ t = 47.6 min maximum F- max(Ub.l if max( h 0 2000 4000 6000 8000 1.10 4 1.2-10 4 St; Basin Temperature Response vs. Time (sec) = 98.8 F = 89.5 F index := Ub index = 99.68 F St. = 2856 sec index ,w= 1,20-7000 i ) >_ maximum maximum = 99.68 F index F- 0 maximum F- 0 for i e 300.. 2400 I maximum +- maxjub i) if max~Ub i l >_ maximum index F- i if max(Ub i) _> maximum index = 476 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H9 Basin Temperature and UHS Heat Load vs. Time Ub~ F linterp(T2, L2, st i) MBT U hr ,w= 1,26- 1000 st d min 77 83 0.1 80.19 713.29 2.6 83.46 680.85 5.1 86.59 658.04 7.6 89.56 639.21 10.1 91.03 922.62 12.6 92.73 888.28 15.1 94.22 853.49 17.6 95.53 821.63 20.1 96.68 793.76 22.6 97.65 716.78 25.1 98.34 619.56 27.6 98.78 526.1 30.1 99.06 507.35 32.6 99.28 488.6 35.1 99.44 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page W M;= 1,20..6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H10 Scenario 8D1 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cell G OOS ORIGIN = 1 in --- 1L lbm = IMF = 1Q sec = 1T gpm := g a l J := 1bm-F MBTU := BTU- 10 6 Cooling Tower Performance min Th l := "119.86 ).F l 112.54) Tcl := r91.861 -F X90.54 122.47 (94.471 Th2 := -F 114.86 Tc2:= (92.86) -F 91.86 Th3 := 119.86) -F TO := -F 90.54 Th4 := 122.47) -F Tc4 := ( 94.47) ) -F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H10 Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2:= T2:= min 823 , hr 19.98 804 21.65 786 23.32 527 29.98 452 39.98 406 49.98 385 59.98 330 83.32 293 116.65 212 166.65 181 333.32 178 480.00 487 480.17 481 540.00 476 600.00 474 627.50 471 660.00 411 660.17 406 732.00 11 386, 732.17 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H102 SX System Flow rate Q l := 64945. gpm (Total flow to TI and T2 gpm) Q2:= 64945 . gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068 . 10 6. gal (Design input 2.1) p := 8.33. Ibm - Mb := p-V gal Fans (Active/Total) Time Constant fl l := 0.948 n2:= 0.948 f21 := 0.375 f22 := 0.375 C P := 1. BTU F- lbm Mb = 8.9 x 10 6 1bm Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.531 a2 := 0.531 01 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Th1,Tcl) B11 := intercept(Th1,Tc1) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) M11 = 0.18 B11 = 70.246F M12 = 0.18 B12 = 70.246F M21 = 0.212 B21 = 68.56 F M22 = 0.212 B22 = 68.56 F CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H1( Calculate Intermediate Constants Al :_ -tl - al-[(1 - fl 1) + f] I -M11] - (1 - al)-(1 - f2l + f21.M21)] A2 := (-Q 2)-[1 - a2.[(l - f12) + f12M12] - (1 - a2).(1 - f22 + f22-M22)]

D1 :[3l-(1-fll+f11.M11)+(1-/3l)

.(1-f21+f21.M21) _ D2 :_ [32.(l - M + fl2_M12) + (1 - [32).(1 - f22 + f22.M22) M b'C P C1 := Q1- a1-f-B11 + (1 - al)421,B21 V Integrating to Solve for Basin Temperature

.= 82-F i s= 1 .. 99 H:= .1 - min st. := M linterp(T2 , L2, st i) I Mb. CP M b-C P = 100..299 I~:= .1-min st i := i - H -H Ub i+1 '- Ubi + [(A1 Ub i) + (linterp(T2,L2,st i), D1) + (C1)]-H wiuse_ th o o erap e ta heat load tor action at t=30 minutes to reduce heat load = 300..2400 1~:= .1 -min st i := i - H i+1 := Ubi + C (A2.Ubi) + (linterp(T2, L2, st i).D2) + (C2)].H use uprate heat load with operator action at t=30 minutes to reduce heat load a2412-B12

+ (1 - a2)422-B22 C2:= Q2. V Al=-0.031 D1 10 =505x 8 F F min BTU C 1 = 2.88 min 1 8 F A2 = -0.03 D2 = 5.05 x 10 F min BTU C2 = 2.88 min CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H o Ub i Results_: 107 103 3 1 99 95 91 87 83 79 75 ,w= 1,20-7000 0 2000 4000 6000 8000 1 10 4 .2_10 4 St; Basin Temperature Response vs. Time (sec) use ugrate heat load maximum := maximum F- 0 for i E 200.. 2400 max(Ub) = 99.67 F @ t = 29.6 min maximum F- max(Ub.l J = 99.7 F 94.5 F index := Ub index = 99.67 F St. = 1776 sec index if max( >_ maximum maximum = 99.67 F index <- 0 maximum f- 0 for i E 200.. 2400 1 maximum E-- max(Ub i) if max(Ub i) >_ maximum index E-- i if max(Ub i) >_ maximum index = 296 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H1 Basin Temperature and UHS Heat Load vs. Time F linterp(T2, L2, st.) MBTU hr ~= 1, 26.. 1000 St. i min 82 83 0.1 85.19 713.29 2.6 88.46 680.85 5.1 91.59 658.04 7.6 94.53 639.21 10.1 95.37 922.62 12.6 96.45 888.28 15.1 97.37 853.49 17.6 98.15 821.63 20.1 98.8 793.76 22.6 99.32 716.78 25.1 99.6 619.56 27.6 99.66 526.1 30.1 99.61 507.35 32.6 99.52 488.6 35.1 99.4 469.85 37.6 CALCULATION NO. NED-M-MSD-9 REVISION NO. 8, Appendix H Page H1 1000 800 600 fnter~T2, L2, sti) ((MBTU~ hr 400 200 ,w= 1, 20 .. 6000 Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix H PAGE H107 37 la"2c , 30,:OSPrA :c ANGRE,'LA.~ARtn=At:U:,ss.^, en P~~a'v'i Seen FssSWrsal Sates manager, Wet Coc4ing P'icdwm SPX Coo1in9 Twchr~cicgies 4141 Sladeeww Crescent. Ur;t 19. MrssissaL,7a, Or*. Canada LS ST1 Te4: + 1 905 547 6446 ext. 348. Cell: -1 905 46.4 8438, Fax: +1 913 693 9332 E-`fad. pact,Spoon~bct SPX tom 'he wfwrnation ocmtaineo m -ti5 t~iet47r.lC mad t-m,tnissx~n

~s wtereded lr,, SPX Corporation fo: +-i , us: of the named ~ndivxlw!

or emit;, -o wft~ch it is directed and Tray c~tan ir.for ..ation chat +s oanf:derxal tx pnokged. ff you have " eceived this elecacnir, rruil vans-issirn . ~error, Gfease del.k e rt +tom year system , ,6d-aur cop; ng w forwardwtg

f. ono nctif;" tfve serder ci the em r b;-.epk. ernad so that aha son aodress reeds can 6c aorr In ar, earlier risat to fAL, we britrF, ji3rmad the estimated oer~~ance of a t: 7~~ling rawer wyth the fan irnapwablv. NJe ate long a:n anal; ~rs :nr E.retnn's B;Ton Sra6on to e~al~uate post -accident eoofing tower basin 'ernperstvres-ccnsrderi".q faijEtK of sonM fans to operate due to postutate-j sir,gte faiftn-es. tornado issdes. etc.. For some scerurios" He want to edit somr fmred apwarnt of cookrng ^apabilw,, !rm cell !an not v~pa. song) w th -wer s ,p being d*~iy"d to that cell. Gin ; ou give us ;rnu best -;tirnaw as to What 'ecrrd of perftxrrarrce one coulc er,pect from an inarrwr rr~tanrcal c+aft wet ccalir:g towel 1e g.. per,--,em of normal F-11 cclo6n9 caper-p')

"% I recall ,.oc mentioned that SPX ma have scone " nforrnaoon

" itera+ure, or past substantiate surh an esttmata. Is tfs,s wflrmation a:ail-~ or p+c,prwtar, ~ r=1,c AEL.A NcVx~3~sa!ge-gitndd,CM Re UV ZPan~al ZrAt, , C"-whs'tg.Toenat". Incvracfe Fans seiedion i can offer clearwr erpvctaber

". ix" rr. `c AhitFF.iV.hC'Af?LtP+7fCD+m,~~Hmrr catty -atyn-d bt~, harw.el C~~R l:,,k vj T- Axt,xn ATTACHMENT 5 Information Supporting Validation of Assumption

3.1 Verification

of Assumption 3.1 of Analytical Basis for Proposed Changes to Technical Specifications Pages 11 through 116 I CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I PAGE 11 APPENDIX I Validation of 10% Cooling with No Fans Running CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I PAGE 12 1.0 PURPOSE The purpose of this Appendix is to validate Assumption 3.1 from Appendix H of this calculation. Assumption

3.1 states

that effectively 10% of the water running through passive cooling tower cells will be cooled when the fans for those cells are not operating. 2.0 DESIGN INPUTS 2.1 Design Input 2.1 from Appendix H of this calculation applies here. 2.2 The design flow is 13,000 gpm per cooling tower cell [Ref. 4.1] 2.3 The initial service water temperature is 98°F [Ref. 4.11. 2.4 The total heat load to be dissipated for both units is 150 x 10 6 Btu/hr [Ref. 4.1]. 2.5 The wet bulb temperature used is 78°F [Ref. 4.11. 2.6 The cooling tower performance curve for this case is based on tower performance data from "design scenario" of BYR97-127, Rev. 1 [Ref. 4.2]. 3.0 ASSUMPTIONS 3.1 (3, estimated as the fraction of load to Tower 1, is assumed to be 0.530, based on the results in Appendix H of this calculation. 3.2 During testing the actual cooling tower heat removal was found to be less than the vendor predicted performance curves [Ref. 4.3]. Thus the original Ceramic Cooling Tower (CCT) analysis used in Ref. 4.1 is also assumed to over predict tower performance with no fans in operation. Since the MRL model was based on test data or actual performance, a factor must be added to the fraction of flow cooled in the Mathcad model to more accurately compare the CCT report [Ref. 4.11 to the MRL model.

4.0 REFERENCES

4.1 Ceramic

Cooling Tower Company Engineering Report NCT-683-55, "Response to S&L Letter of 11-17-81; Complete Loss Of Fans," December 10, 1981. (See pages 113 through 116) 4.2 BYR97-127, Rev. 1, "Byron Ultimate Heat Sink Cooling Tower Performance Calculations

." 4.3 "Essential Service Water Cooling Tower Performance Test Program Report" attached to S&L letter DFB-70 dated 1/19/89, CHRON # 145710. 5.0 IDENTIFICATION OF COMPUTER PROGRAMS The maximum service water temperature was determined by running Mathcad Version 11.2a, Program Number 03.7.548-11.2. All computer runs using Mathcad were made on Sargent and Lundy L.L.C. PC No. ZL4512 from Controlled File Path: C:\Program Files\MathSoft\Mathcad 11 Enterprise Edition\.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I PAGE 13 6.0 METHOD OF ANALYSIS 6.1 Design Validation A validation of the cooling effectiveness of passive SX cooling tower cells without fans operating is performed by benchmarking against results of a previous analysis performed by the tower vendor, Ceramic Cooling Tower (CCT). The CCT analysis [Ref. 4.11 was performed to predict peak SX basin water temperature under certain heat load and wet bulb temperature conditions following a tomado, with a postulated failure of all SX tower fans. The initial conditions assume a basin temperature of 98°F [Ref. 4.1]. This scenario assumes no tower cells are out of service (OOS). Initially, the fans on all the cells are not running and all the bypass valves are closed. The total heat load to be used for this scenario is 150 x 10 6 Btu/hr [Ref. 4.11. There is one set of parameters f, Q, M1, B1, M2, B2, a, and R that are determine the basin temperature response. The T ho , vs T co , d relationship is illustrated in Figure I-1. Determination of f, Q, M1, 61, M2, B2, a, and R. f11. f12 f21. f22 Flow through operating cells in T1 Total flow through T1 including bypass flow = 52,000 (.10) gpm = 0.100 52,000 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow = 52,000 (.10) gpm = 0.100 52,000 gpm M11, B11, M12 L 1312 needed to This is equal to the total flow to T1 and T2, (52,000 + 52,000) gpm = 104,000 gpm Based on an average flow of 13,000 gpm per cell in T1, the tower performance for T1 is generated using a flow of 13,000 gpm (Figure I-1). Based on the T H , T c values (as determined from the TH values calculated for tower operation in Design Input 2.6), [(144.26, 104.26), (136.54, 102.54)1, Mathcad calculates M11, M12 and B11, B12 from the tower performance inputs.

I CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I PAGE 14 M21, B21, M22-B22: __ a 7.1 Fraction of Flow Factor Based on an average flow of 13,000 gpm per cell in T1, the tower performance for T1 is generated using a flow of 13,000 gpm (Figure 1-1). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 2.6), [(144.26, 104.26), (136.54, 102.54)], Mathcad calculates M21, M22 and B21, B22 from the tower performance inputs. = Flow to T1 = 52,000 gpm = 0.500 Total SX flow, Q 104,000 gpm R is estimated as the fraction of load to Tower 1, which is assumed to be 0.530 (see Assumption 3.1). Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, coefficients A, B, and C in Eq (3), renamed AVA2, D1/D2, and C1/C2 here, calculated by Mathcad. The output from the MathCAD calculation for this scenario is shown on pages 16 through 112. The maximum basin temperature, Tbmax, is calculated to be 113.7°F. 7.0 NUMERICAL ANALYSIS 8.0 RESULTS AND CONCLUSIONS the are The CCT report states that the design of the cooling tower has a range of 40°F (138°F-98°F). The cooling tower performance data for "design scenario" from BYR97-127

[Ref. 4.2] shows that, by interpolation, the range is 22.2°F (Range = HWT - CWT = 120.2°F-98°F). Therefore, the current tower performance was about 56% (22.2°F / 40°F) of expected. The Mathcad model performance will be inflated by a factor of 1.56 to account for this difference. This is done by increasing the flow factors (f11, f12, f21, and f22 originally at 0.1) by 56% which yields 0.156 for the flow factors (fl 1, f12, f21, and f22). The results for the design validation case show that the maximum basin temperature is 113.7°F. The maximum temperature determined in Ceramic Cooling Tower (CCT) Engineering Report NCT-683-55

[Ref. 4.1] was 109.3°F. This shows that greater than 10% cooling was used to calculate the maximum basin temperature with no fans running, and that using 10% cooling is conservative, relative to the CCT report.

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I PAGE 15 Figure I-1: Design Tnue (°F)

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page Design Verification Two Tower Model - (Heat load for Power Uprate) ORIGIN=- i in=- IL lbm --- 1MF --= IQ sec=- IT gpm := g a l ~.= Ibm-F MBTU := BTU. 106 min Cooling Tower Performance Th 1 := Th2 := 104.26 144.26 (136.54 ~ 102.54) -F Tc1:= C136.54) F Tc2:_ (1104.26 02.54) -F -F Th3 :_ (136.54).F TO _ (1104.26 02.54) Th4 := (1 144 6.54) F Tc4 := (102 104.54.26 ) . F CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page L2 := Uyrate Heat load (L42) 150 0.00 150 0.17 150 0.35 150 0.50 150 0.75 150 2.00 150 2.17 150 2.33 150 2.50 150 3.32 150 4.98 150 6.65 150 8.32 150 9.98 150 11.50 150 11.65 150 13.32 150 14.98 150 16.65 150 MBTU T2 18.32 := min 150 . hr 19.98 150 21.65 150 23.32 150 29.98 150 39.98 150 49.98 150 59.98 150 83.32 150 116.65 150 166.65 150 333.32 150 480.00 150 480.17 150 540.00 150 600.00 150 627.50 150 660.00 150 660.17 150 732.00 150 732.17 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page SX System Flow rate Q l := 104000. gpm (Total flow to T1 and T2 gpm) Q2:= 104000.gpm (Total flow to T1 and T2 gpm) Basin Mass V:= 1.068-10 6. gal (Design input 2.1) p:= 8.33- lbm g al Mb := p - V C := I. BTU P F- lbm Fans (Active/Total) Time Constant fl I:= 0.156 f12 := 0.156 f21 := 0.156 f22 := 0.156 Mb = 8.9 x 10 6 1bm V V T 1 := - T2:= - Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.5 a2 := 0.5 01 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl)

M21 := slope(Th2,Tc2) 1311 := intercept(Th1,Tcl)

B21 := intercept(Th2,Tc2)

M12 := slope(Th3,Tc3)

M22 := slope(Th4,Tc4)

B12 := intercept(Th3,Tc3)

B22 := intercept(Th4,Tc4)

MI I = 0.223 BI I = 72.119F M12 = 0.223 B12 = 72.119F M21 = 0.223 B21 = 72.119 F M22 = 0.223 B22 = 72.119 F CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page Calculate Intermediate Constants "1 A l := - al.[(1 - fl l) + f11.M11] - A2 := (-Q 2),[1 - a2.[(1 - f12) + fl2-M12] - DI f11+fll.Mll)+(1-[31)-(1-f21+f21.M21) M b-C P D2 := (32.(1 - f12 + fl2. C1 := Q1 a1-fl1-B11

+ (1 ~ V C2:= Q2 a2412-B12

+ (1 ~ V Al=-0.01 1 min A2=-0.01 1 min Integrating to Solve for Basin Temperature Ub l := 98-F i:= 1..299H:= .1-min st i := i-H i+1 := Ubi+ [(A1.Ub i l + (linterp(T2,L2,st i l-D1) + (Cl)].H with o ra use upr era heat load l , tor action at t=30 minutes to reduce heat load ;= 300.. 15000 := . 1 -min St i-H + [(A2-Ub i) + (linterp(T2,L2,st i).D2' + (C2)]-H use uprate heat load with operator action at t=30 minutes to reduce heat load 12) + (I - (32)-(1 - f22 + f22-M22) M b'C P - c,0421-B21 - a2)422-B22 D1 =9.88x 10-8 F F BTU Cl = 1.1 min D2 =9.88x 10 8 F F BTU C2= 1.1 min (1 - al).(1 - f21 + f21.M21)] (1 - a2)-(1 - f22 + f22.M22)]

CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page I , Results 130 125 120 115 Ubi 110 105 100 95 90 use uprate heat load 0 210 4 - 10 4 4 4 st; max(Ub) = 113.71 F Ub 300 = 102.7 F Basin Temperature Response vs. Time (sec) = 99.7 F maximum= 113.71 F index := index= 1.5 x 10 4 index = 113.71 F St. = 90000 see index ;= 1,20-15000 maximum := maximum E- 0 for i c 300.. 15000 maximum <- max(Ub) if max( i) >_ maximum index F- 0 maximum +- 0 for i c 300.. 15000 I maximum <- max(Ub i) if max(Ub i) >_ maximum index <- i if max(Ub i) > maximum CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix I Page I Basin Temperature and UHS Heat Load vs. Time F linterp(T2 , L2, st) MB T U hr ,~;= 1,26.. 1000 st i min 98 150 0.1 98.46 150 2.6 98.9 150 5.1 99.33 150 7.6 99.75 150 10.1 100.16 150 12.6 100.55 150 15.1 100.93 150 17.6 101.31 150 20.1 101.67 150 22.6 102.02 150 25.1 102.36 150 27.6 102.69 150 30.1 103.01 150 32.6 103.32 150 35.1 103.62 150 37.6 CALCULATION NO. NED-M-MSD-009 REVISION NO. 8, Appendix i Page I' 1000 800 C 600 fnter~T2, L2, st i) MB F T U) hr 400 200 = 1,20..6000 1000 2000 3000 4000 5000 6000 St; Post LOCA Time (sec) UHS Accident Heat Load Profile L42 TO ATTENTION OF N NO. NED-M-MSD-09 Sargent & Lundy Engineers 55 East Monroe Street Chicago, Illinois 60603 REVISION NO. 8, Appendix I Page 113 cerw* c (*Tip" a subsidiary of Justin Industries. Inc. P. O. 9oac 425 " Fat Worth, Texu 76101 " 617 335-2474 Date December 17, 1981 Transmittal No. 158 Ceramic Order No. NCT-683 Recipient Ref. No. 181185 Mr. Ken Greene Name of Job Commonwealth Edison Company Byron Station, Units 1 & 2 6. Comment/Approval Due Dote 7. Information Only 8. Other Enclosed are the following documents for action and/or use as indicated. It is the recipient's responsibility to replace aid documents, if any, with new documents and to destroy, return or suitably mark obsolete material. ACTION DOCUMENT DOCUMENT DATE NUMBER NO. USE NO. REV. ISSUED OF COPIES TITLE C-652 -- .NCT-683-55 0 12/10/81 1 RESPONSE TO S&L LETTER OF 11/17 COMPLETE LOSS 0 FANS CERAMIC COOLING TOWER CO. L. DALEY MGR. - PROJECT ENGINEERING A. B. DOCUMENT USE Preliminary

Not for Construction.

Reference:

Not for Construction ACTION NUMBER 1.. Approved-Manufacturing may proceed. 2. Approved-Submit final dwg, " Mfg. may proceed. C. For Approvals Not for Construction. 3. Approved except as noted " Make changes and submit D. Construction

May be used for final dwg - Mfg. may proceed as approved. E. As Built construction 4, Not Approved - Correct and resubmit. 5. Review not required - Mfg. may proceed.

. CALCULATION NO. NED-M-MSD-09 REVISION NO. 8, Appendix I Page 114 feC TION NCT-583-55 COMMONWEALTH EDISON COMPANY BYRON STATION - BYRON, ILLINOIS DESIGN SPECIFICATION NO. F-2.848 12/10/81 OATC CERAMIC COOLING TOWER COMPANY FOR SARGENT & LUNDY ENGINEERS AGENTS FOR PREPARED ell REVIEWED (THERMAL ENGINEER)

ENGINEERING REPORT NCT-683-55 RESPONSE TO S&L LETTER OF 11-17-81; COMPLETE LOSS OF FANS CERAMIC COOLING TOWER COMPANY 0 wisilio#V

i Justin InduNr4s, Inc. FORT WORTH. TEXAS ,o, N ,NCT-5 8 3 REVISION 0 REV. 1 REV. 2 REV. 3 W2M P L- I I RESPONSE TO S&L LETTER OF 11/17/81; COMPLETE LOSS OF FANS . CALCULATION NO. NED-M-MSD-09 PURPOSE The purpose of this Report is to respond to Sargent and Lund y's Request for Predicted Performance of the Cooling Tower when subjected to the Postulated Conditions described below. The resulting performance of the Tower when sub-jected to these conditions is a predicted value and is not guaranteed Tower Performance. PROBLEM STATEMENT The problem (as stated in SQL Letter of 11/17/81) is a loss of offsite power as a result of a tornado. In addition, all eight Essential Service Water Cooling Tower Fans are in-operable due to impact of vertical tornado missiles. There-fore, it must be demonstrated that the plant will be shut-down safely following this event. The postulated shutdown conditions to which the Tower will be subjected are as follows; Total Heat Load to be S Dissipated for both Units. = 150 x 10 BTU/HR Initial Service Water Temperature entering the 0 Plant. = 91 F Design Flow No. of Cells Operating = R Fan RESPONSE TO S& L LEVER OF 11/17/81 COMPLETE LOSS OF FANS Operation REVISION NO. 8, Appendix I Page 115 = 13000 GPM/CELL Of f CERAMIC COOLING TOWER COMPANY e wbsidiaiy s) Jsdn IndvoRss, Inc. FORT WORTH, TEXAS Range that the Tower will see = 2.-9 0 F Wet Bulb = 78 0 F CALCULATION NO. NED-M-MSD-09 REVISION NO. 8, Appendix I Page 116 3.0 PREDICTED PERFORMANCE The original Design Conditions of the Tower are: 3.1' The Tower, as designed, was subjected to the postulated shutdown conditions shown in ?..1 above. SECTto" NCT-683-55 Upon completion of the first cycle of. cooling through the cooling loop, the predicted Tower cooling will be: HWT Entering Towers 93.9 0 F CWT Leaving Tower Fill Area- 92.&0 F Heat Dissipated for 1st Cycle 57.2 x 10 6 BTU/HR 3.2 Since it is predicted that the Towers cannot dissipate the full heat load in the first cycle, the HWT will continue to rise and ultimately the Towers will reach a predicted oper-ating equilibrium of: HWT Entering Towers 112.2 0 F CWT Leaving Tower Fill Area 109.3 0 F Heat Dissipation 150 x 10 6 BTU/HR This operating equilibrium dces not take into account: Basin Mixing Dissipation of Part of the Heat Load thru other available cooling methods. wtvtatot+0 RESPONSE TO S&L LETTER OF 11/17/81; COMPLETE LOSS OF FANS CERAMIC COOLING TOWER COMPANY a soksid.aey of J.stia Indusuias, Ire. FORT WORTH, TEXAS joe waNCT-6 8 3 Design Flow - 13000 GPM/CELL HWT = 138 0 F CWT 9P' F WBT 78 0 F ATTACHMENT 6 Simplified Drawings of Scenarios 8A, 8B and 8131, 8C and 813, 8C1, and 8C2 Simplified Drawings of Scenarios for TS Changes to SX T emperature_

Scenarios 8A, 8B and 8131, 8C and 813, 8C1, and 8C2 SCENARIO 8A POST LOCA CONFIGURATION TOWER B H G 22 22 Oo Oo FAILED TOWER A j x x x 2B 1B X x V 1A 2A RCFC RCFC U U U RCFC RCFC N S7 M~ A B C D 11 11 21 21 Oo 00 00 Oo OOS--SOWER B H SCENARIO 8B & 8D1* POST LOCA CONFIGURATION FAILED TOWER A 28 1B 2A 1A x x x 2B 1B v 1A 2A RCFC RCFC c~ t~ U RCFC RCFC N 0 m~ G~ 22 C>4 A B C D 11 11 21 21 C4 CO CXJ C>-o

FOR SCENARIO 8D1 NO COOLING IS ASSUMED FOR 10 MINUTES.

2B RGFC G 22 00 A 11 00 OOS--ti oWER B H 22 00 SCENARIO 8C & 8D* POST LOCH CONFIGURATION oos FAILED TOWER A B C D 11 21 21 c>O GO C>O

FOR SCENARIO 8D NO COOLING IS ASSUMED FOR 10 MINUTES. 1B x x x U 1A 2A RGFC v v c,~ RGFC RCFC N e r- T OOS SCENARIO 8C1 POST LOCH CONFIGURATION TOWER B x x x 2B 18 v v 0 1A 2A RCFC RCFC v c~ c~ RCFC RCFC N 0 r- HVG 22 ~ 22 c>0 C><O FAILED TOWER A A B C D 11 11 21 21 22 22 00 oa SCENARIO 8C2 POST LOCA CONFIGURATION OOS x x x 2B 1B U U U 1A 2A RCFC RCFC U U U RCFC RCFC N 0 M~ B'-11 C>>0 11 00 TOWER B H G FAILED C D 21 21 00 oa ATTACHMENT 7 Evaluation of Additional Scenarios for Postulated Single Failures of Electrical Breakers Evaluation of Additional Scenarios for Postulated Single Failures Pages 131 through B55 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 131 APPENDIX B Scenarios 10 -13 Evaluations CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 132 B.1 PURPOSE The purpose of this Appendix is to incorporate additional scenarios 10 through 13 for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCH and a LOOP on one unit with the opposite unit in normal shutdown as described in UHS-04 [Ref. B.4.4]. B.2 DESIGN INPUTS B.2.1 All design inputs from the calculation main body section 4.3.1 are valid for this Appendix B calculation. B.2.2 SX water inventory per tower is equal to the basin volume of 59%, or 40,578 ft 3 [Ref. B.4.10], which is one percent below the Technical Specification minimum value of 60% [Ref. B.4.5]. The volume of water in the return and supply piping of 34,043 ft 3 is then added [Ref. B.4.7] to the basin volume. The volume of silt in the basin (3,312 ft 3 per basin per Ref. B.4.6) is subtracted from the SX water inventory used for the calculation so that it is not included as part of the heat sink. The total (for both towers) SX water inventory volume = [(40,578-3,312) ft 3 + 34,043 ft 3] per tower x 7.48 gal/ft 3 x 2 towers = 1.068 x 10 6 gallons. B.2.3 The accident scenarios used in this revision of the calculation are taken from UHS-04 [Ref. 8.4.3] Attachment B and are consistent with scenarios 10 through 13 in BYR96-259

[Ref. B.4.2] and BYR97-127

[Ref. B.4.1]. B.2.4 Flows through the two trains of the SX tower for accident scenarios 10 through 13 are taken from BYR96-259

[Ref. B.4.2], Attachment C and BYR97-127

[Ref. B.4.1], Attachment C and are discussed in more detail in Section B.7.1. B.2.5 LOCH unit heat loads are taken from Table 9 of ATD-0063, Rev. 4B [Ref. B.4.4]. These heat loads take into account the reduced miscellaneous heat load, which includes subtracting 8.13 x 10 6 Btu/hr for the recycle evaporator package since it was retired in place, and using the sum of the total miscellaneous heat load (90.7 x 10 6 Btu/hr) rather than the 103 x 10 6 Btu/hr used previously. These heat loads include non-accident heat loads, accident heat loads, and miscellaneous heat loads. B.2.6 Cooling tower performance curves for scenarios 10 through 13 are based on tower performance data from scenarios 10 through 13 of BYR97-127

[Ref. B.4.1], Attachment E. Since the MRL model for the Byron UHS Cooling Tower was validated only down to a minimum flow of 6,000 gpm, tower performance data for average flow less than 6,000 gpm are not generated. For scenarios having an average flow less than 6,000 gpm, an average flow rate of 6,000 gpm is used to calculate the performance data. This is conservative since tower performance generally improves with lower flow. B.2.7 The cooling tower flow rates used in this calculation have 250 gpm subtracted from them, as described in Appendix D of calculation NED-M-MSD-009

[Ref. B.4.9], to account for losses out of the 2-inch drain line per P&ID M-42, Sheet 7 [Ref. B.4.11]. B.3 ASSUMPTIONS B.3.1 All assumptions in the calculation main body section 4.2 are valid for this Appendix B calculation. B.3.2 The fraction of water cooled for SX cooling tower cells with fans not running is assumed to be 0.10 (i.e., 10% of the water delivered to that cell is effectively cooled). This is (CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B3 I based on input from the cooling tower manufacturer as a reasonable estimate of minimum cooling tower performance without fan air flow [Ref. B.4.8]. Also, shown in NED-M-MSD-09

[Ref. B.4.9], Appendix I, is a Mathcad model verifying that 10% cooling is conservative with no fans running. For scenarios where a tower has at least one active cell, tower performance curves are based on the average flow to the active cells. This approach is justified since the majority of the cooling is provided by the active cells, and the difference in flow between tower cells is small. For Tower B in scenario 13, there are no active cells. In this case, the tower performance curve is based on the average flow to the passive cells. 8.

4.0 REFERENCES

B.4.1 BYR97-127, Rev. 1, "Byron Ultimate Heat Sink Cooling Tower Performance Calculations

." B.4.2 BYR96-259, Rev. 2, "SX System FLO-Series Analysis." B.4.3 Attachment B to UHS-04, Rev. 3, "Ultimate Heat Sink Design Basis LOCH Single Failure Scenarios for Cool Weather Operation." 6.4.4 ATD-0063, Rev. 004B, "Heat Load to the Ultimate Heat Sink During a Loss of Coolant Accident." B.4.5 Byron Technical Specifications 3.7.9, Amendment 159. B.4.6 SX-TH01, Rev. 0, "Water Volume in SX System Outdoor Piping & SX Tower Basin," June 25, 1987. B.4.7 BYR97-034, Rev. OA, "Essential Service Water Cooling Tower Basin Minimum Volume Versus Level and Minimum Usable Volume Calculation," June 28, 2005. B.4.8 Email from Paul Secen (SPX) to M.A. Nena (S&L) dated July 18, 2008 1:05 PM, subject: Re: Mechanical Draft Cooling Tower Performance With Inoperable Fans (see page B55). B.4.9 NED-M-MSD-009, Rev. 008, "Byron Ultimate Heat Sink (UHS) Cooling Tower Basin Temperature

Part IV." B.4.10 NED-M-MSD-014, Rev. 008A, "Byron Ultimate Heat Sink Cooling Tower Basin Makeup Calculation

." B.4.11 Exelon Drawing M-42, Sheet 7, Rev. AE, "Diagram of Essential Service Water." B.5.0 IDENTIFICATION OF COMPUTER PROGRAMS The maximum service water temperature was determined by running Mathcad Version 11.2a, Program Number 03.7.548-11.2. All computer runs using Mathcad were made on Sargent and Lundy L.L.C. PC No. ZL4512 from Controlled File Path: C:\Program Files\MathSoft\Mathcad 11 Enterprise Edition\.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B4 B.6.0 METHOD OF ANALYSIS Appendix B of this calculation will use the ESW cooling tower transient model from Revision 1 of this calculation to calculate the basin temperature response for additional scenarios 10, 11, 12, and 13. Appendix B uses the Mathcad calculations from Appendix A with the changes summarized below: 1) The revised Total Heat Load to the UHS curve from ATD-0063 [Ref. B.4.4] (Table 9) will be incorporated. The total heat load includes the power uprate heat input. This curve is the summation of the non-accident unit RHR heat load, the accident heat load, and the miscellaneous heat load from both units. 2) New scenarios 10, 11, 12, and 13 are being evaluated for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCH and a LOOP on one unit with the opposite unit in normal shutdown as described in UHS-04 [Ref. B.4.3]. 3) For scenarios 10, 11, 12, and 13 new flow rates and tower performance curves were generated

[Ref.'s B.4.2 and B.4.1] and are used as inputs. 4) New scenarios 10, 11, 12, and 13 are modeled in Mathcad to be consistent with the format from the Mathcad models of Appendix G of NED-MSD-009

[Ref. B.4.9]. 5) Partial credit is taken for cooling (10%) in tower cells with water flow but no fan in operation (see Assumption B.3.2). For scenarios where a tower has at least one active cell, tower performance curves are based on the average flow to the active cells. This approach is justified since the majority of the cooling is provided by the active cells, and the difference in flow between tower cells is small. For Tower B in scenario 13, there are no active cells. In this case, the tower performance curve is based on the average flow to the passive cells. The Byron ESW cooling tower performance is acceptable if the calculated basin temperature is below the SX cooling tower basin design temperature of 100°F B.6.1 Tower Performance Curves The tower performance curves are shown in Figures B-1 through B-8 for each scenario. Each tower performance curve is based on a 70°F wet bulb temperature. These figures plot T Hot vs Tcold for each tower performance curve for each cooling tower as provided by BYR97-127

[Ref. B.4.1]. For each scenario, two points were selected from the applicable tower performance curve to provide a linear approximation of tower performance over the range of THot and Tco,d temperatures expected for that scenario. The selected points are checked against final results to confirm their applicability to the actual temperature range. These points are listed as Th1, Th2, Th3, Th4, Tc1, Tc2, Tc3, and Tc4 in the Mathcad models. B.7.0 NUMERICAL ANALYSIS B.7.1 Flow Rate Analvsis As discussed in BYR96-259

[Ref. B.4.2] and BYR97-127

[Ref. B.4.1], leakage is taken into account when determining the average flow rates. Also, in order to account for 10% cooling for passive fans (see Assumption B.3.2), the flow rate for that cell is multiplied by 0.1 after leakage is taken into account as shown in the tables below.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B5 To calculate the flow through the operating cells 250 gpm is subtracted from each open riser to account for the flow in the open 2" riser leak-off line (see Design Input B.2.7). 8.7.1.1 Accident Scenario 10 The single failure considered for Scenario 10 is the loss of power to Cells E and F bypass basin valve OSX162B and Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 74°F with one SX pump running on each unit. This scenario assumes two tower cells (A and G) are out of service (OOS). Initially, the fans on all the other cells are not running, all the bypass valves are open, and all the riser valves are closed. Operator actions are required in the control room to turn on the cooling fans and close the bypass valves within 10 minutes following safeguard signals. Bypass valve OSX162B is assumed to fail to close upon operator actions in the control room (failed bypass valve). This requires manual closing of the bypass valve which is assumed to take 30 minutes after the safeguard signals. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 9 of ATD-0063, Rev. 4B (Ref. 8.4.4). Since the UHS tower flows are different between the time period before and after the failed bypass valve is closed, two sets of parameters f, Q, M1, B1, M2, B2, a, and R are needed to determine the basin temperature response. The first set is used to calculate the basin temperature for the condition with the failed bypass valve remaining open. The second set is used for the condition with the failed bypass valve closed. For the time period from 10 - 30 minutes after the accident (with operable cooling tower fans at high speed, and the failed bypass valve remains open): The UHS tower flows, based on Scenario 10 (10-30 min) are shown in Design Input B.2.4. The Th ot vs TwId relationship is illustrated in Figure B-1. Determination of f, Q, M1, B1, M2, B2, a, and R. Scenario 12 10-30 min Scenario 12 -30 min Scenario 13 10-30 min Scenario 13 >30 min Flow through o rating cells in T1 11,272+11,257-500=

22 029 12,615+12,598-500=

24,713 7,335+7,247+7,207+

7,196 - 1000 = 27,985 9,402+9,291+9,240+

9,227 - 1000 = 36,159 B.4.2 Total flow through T1 11,272+11,2

+268+26 + 831 = 23,895 12,615+12,598+280+

278 + 858 = 26,626 7,335+7,247+7,207+

7,196 + 768 = 29,753 9,402+9,291+9,240+

9,227 + 797 = 37,956 B.4.2 Flow through operating cells in T2 2,855+2,365-500+(3,589 250)'0.1+(3,348-250)'0

.1 -5,364 9,252+9,238-500+

(9,423-250)"0

.1+(9,306 250)'0.1 - 19,813 (3'404-250)'0

.1+(2,973 20'0.1 = 588 (12,672-250)'0

.1+ (12,651 - 250)'0.1 = 2,482 8.4.2 Total flow. through T2 2,855 + 2,365 + 3.589 + 3,348 + 28,633 = 41,060- 9,252 + 9,238 + 9,423 + 9.308_+ 793 = 38,012- 3,404 + 2,973 + 273 + 272 2 8,590 = 35,512 I _ 12,672 + 12,651 + 270 + 270 + 851 = 26,714 ~ I B 4 2~ Scenario 10 10-30 min Scenario 10 -30 min Scenario 11 10-30 min r Flow through operating cells in T1 9,373 + 9,322 + 9,308 _ 750 = 27,254 14,048 + 13,973 + 13,955 750 = 41,226 8,895 + 8,846 + 8,834 - 750 = 25,825 10,450 + 10,393+"10,379 750 = 30,472 - B.4.2 Total flow through T1 9,373 + 9,322 + 9,309 + 255 + 798 = 29,057 14,048 + 13,973 + 13,955 + 270 + 884 = 43,129 8,895 + 8,846 + 8,834 + 270 + 791 = 27,635 10,450 + 10,393 + 10,379 + 284 + 815 = 32,321 8.4.2 Flow through operating cells In T2 5,641 - 250 = 5,391 18,695 - 250 =18,445 2,082-250+(3,531-250)'0.1 +(3,064- 250)'0.1 = 2,442 10,411-250+(10,506-250)`0.1 +(10,444-250 '0.1 =12,206 8.4.2 Total flow throu h T2 286 + 274 + 262 + 5,641 + 29,526 = 35989 118,695 + 284 + 283 + 283 + 932 = 20,477 1 3,531 + 3,064 + 258 + 2,082 + 28,590 =.37,525 I 10,506 + 10,444 + 273 + _10,411 +812 = 32,445 8.4.2 Average flow per cell in T7 -- , - - i . . - -: - : _ - Average flow per cell in T2 r Flow to RCFC to : r Flaw to RCFCIA+RCFC16 3,180+2,823=6,003 3,055+2,706=5761

_-- 3191-+2,831=8022- 3,157+2,800=6,9578

.42-]

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B6 f21 M21, B21 a1 _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 27,254 gpm = 0.938 29,057 gpm Flow through operating cells in T2 Total flow through T2 including bypass flow = 5,391 gpm = 0.150 35,989 gpm This is equal to the total flow to T1 and T2, (29,057 + 35,989) gpm = 65,046 gpm Based on an average flow of 9,085 gpm per cell in T1, the tower performance for T1 is generated using a flow of 9,085 gpm (Figure B-1). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(115.05, 87.05), (106.94, 84.94)], Mathcad calculates M11 and 1311 from the tower performance inputs. Based on an average flow of 5,391 gpm per cell in T2, the tower performance for T2 is generated using a flow of 6,000 gpm (Figure B-1). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(107.82, 79.82), (100.48, 78.48)], Mathcad calculates M21 and B21 from the tower performance inputs. = Flow to T1 = 29,057 gpm = 0.447 Total SX flow, Q 65,046 gpm a is estimated as the fraction of load to T1. __ Flow to RCFC 1 A __ (3,180) gpm = 0.530 Flow to RCFC 1 A + Flow to RCFC 1 B (3,180 + 2,823) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (1), renamed A1, D1, and C1 here, are calculated for the period from 10 to 30 minutes by Mathcad.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 137 For the time period from > 30 minutes after the accident (with the operable cooling tower fans at high speed, and the failed bypass valve is manually closed): The UHS tower flow, based on Scenario 10 (>30 min) is shown in Design Input B.2.4. The T hot vs T,ad relationship is illustrated in Figure B-2. Determination of f, Q, M1, B1, M2, B2, a, and 0. f12 f22 M12, B12 M22. B22 a2 02 : _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 41,226 gpm = 0.956 43,129 gpm _ F low through operating cells in T2 Total flow through T2 including bypass flow 18,445 gpm = 0.901 20,477 gpm This is equal to the total flow to T1 and T2, (20,477 + 43,129) gpm = 63,606 gpm Based on an average flow of 13,742 gpm per cell in T1, the tower performance for T1 is generated using a flow of 13,742 gpm (Figure B-2). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(122.91, 97.91), (113.28, 94.28)), Mathcad calculates M12 and B12 from the tower performance inputs. Based on an average flow of 18,445 gpm per cell in T2, the tower performance for T2 is generated using a flow of 18,445 gpm (Figure B-2). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(119.52, 103.52), (112.88, 99.88)), Mathcad calculates M22 and B22 from the tower performance inputs. = Flow to T1 = 43,129 gpm = 0.678 Total SX flow, Q 63,606 gpm P is estimated as the fraction of load to T 1.

I CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 138 __ Flow to RCFC 1A = (3,055) gpm = 0.530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,055 + 2,706) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and (3 determined above, the coefficients A, B, and C in Eq (1), renamed A2, D2, and C2 here, are calculated for time > 30 minutes by Mathcad. For this scenario, the basin temperature evaluation is performed in 3 steps: namely, 0-10 minutes, > 10 minutes to 30 minutes, and > 30 minutes. For the initial 10 minutes, since there is no heat removal by the cooling towers, the basin temperature is calculated using Eq (2). The initial basin temperature, Tb o , is assumed to be 74°F. For time > 10 minutes to 30 minutes, operator actions are taken to turn on the cooling fans and close the bypass valves, However, only partial cooling is available due to one bypass valve failing to close. Eq (1) is then used to calculate the basin temperature. The coefficients A1, D1, and C1, are used for this time period. For time > 30 minutes, full cooling becomes available when operator actions are taken to manually close the failed bypass valve. Eq (1) is also used to calculate the basin temperature, utilizing the coefficients A2, D2, and C2. The output from the MathCAD calculation for this scenario is shown on pages B27 through B33. The maximum basin temperature, Tb max , is calculated only to be 98.4°F. The temperature at 30 minutes is calculated to be 96.6°F. Both of these values are below the acceptance limit of 100°F. B.7.1.2 Accident Scenario 11 The single failure considered for Scenario 11 is the loss of power to Cells E and F bypass basin valve OSX162B and Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 74°F with one SX pump running on each unit. This scenario assumes two tower cells (A and G) are out of service (OOS). Initially, the fans on all the other cells are not running, one bypass valve (OSX162B) is open, and only riser valves to cells A and G are closed. Operator actions are required in the control room to turn on the cooling fans and close the bypass valve within 10 minutes following safeguard signals. Bypass valve OSX162B is assumed to fail to close upon operator actions in the control room (failed bypass valve). This requires manual closing of the bypass valve which is assumed to take 30 minutes after the safeguard signals. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 9 of ATD-0063, Rev. 413 [Ref. B.4.4j. Since the UHS tower flows are different between the time period before and after the failed bypass valve is closed, two sets of parameters f, Q, M1, B1, M2, B2, a, and R are needed to determine the basin temperature response. The first set is used to calculate the basin temperature for the condition with the failed bypass valve remaining open. The second set is used for the condition with the failed bypass valve closed. For the time period from 10 - 30 minutes after the accident (with operable cooling tower fans at high speed, and the failed bypass valve remains open):

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 139 The UHS tower flow, based on Scenario 11 (10-30 min) is shown in Design Input B.2.4. The Thos vs T,o,d relationship is illustrated in Figure B-3. Determination of f, Q, M1, B1, M2, B2, a, and R. f21 M11 B11 M21, B21 a1 _ Flow through operating cells in T1 Total flow through T1 including bypass flow __ 25,825 gpm 0'9 35 27,635 gpm - _ Flow through operating cells in T2 Total flow through T2 including bypass flow = 2,442 gpm = 0.065 37,525 gpm This is equal to the total flow to T1 and T2, (27,635 + 37,525) gpm = 65,160 gpm Based on an average flow of 8,608 gpm per cell in T1, the tower performance for T1 is generated using a flow of 8,608 gpm (Figure B-3). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(113.87, 85.87), (105.88, 83.88)], Mathcad calculates M11 and B11 from the tower performance inputs. Based on an average flow of 1,832 gpm per cell in T2, the tower performance for T2 is generated using a flow of 6,000 gpm (Figure B-3). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(107.82, 79.82), (100.48, 78.48)], Mathcad calculates M21 and B21 from the tower performance inputs. = Flow to T1 = 27,635 gpm = 0.424 Total SX flow, Q 65,160 gpm [3 is estimated as the fraction of load to T1. = Flow to RCFC 1A _ (3,191) gpm = 0.530 Flow to RCFC 1A + Flow to RCFC 1 B (3,191+ 2,831) gpm I CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 11310 Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (1), renamed A1, D1, and C1 here, are calculated for the period from 10 to 30 minutes by Mathcad. For the time period from > 30 minutes after the accident (with the operable cooling tower fans at high speed, and the failed bypass valve is manually closed): The UHS tower flow, based on Scenario 11 (>30 min) is shown in Design Input B.2.4. The Thot vs TM relationship is illustrated in Figure B-4. Determination of f, Q, M1, B1, M2, B2, a, and [3. f12 f22 M12 B12 M22. B22 a2 _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 30,472 gpm = 0.943 32,321 gpm Flow through operating cells in T2 Total flow through T2 including bypass flow 12,206 gpm = 0,376 32,445 gpm This is equal to the total flow to T1 and T2, (32,321 + 32,445) gpm = 64,766 gpm Based on an average flow of 10,157 gpm per cell in T1, the tower performance for T1 is generated using a flow of 10,157 gpm (Figure B-4). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(117.76, 89.76), (109.38, 87.38)], Mathcad calculates M12 and B12 from the tower performance inputs. Based on an average flow of 10,161 gpm per cell in T2, the tower performance for T2 is generated using a flow of 10,161 gpm (Figure B-4). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(177.77, 89.77), (109.39, 87.39)], Mathcad calculates M22 and B22 from the tower performance inputs. Flow to T1 ! 32,321 gpm = 0.499 Total SX flow, Q 64,766 gpm (CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE 1311 R is estimated as the fraction of load to T1. __ Flow to RC FC 1A = (3,157) gpm = 0.530 Flow to RCFC 1A +Flow to RCFC 1 B (3,157 + 2,800) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and P determined above, the coefficients A, B, and C in Eq (1), renamed A2, D2, and C2 here, are calculated for time > 30 minutes by Mathcad. For this scenario, the basin temperature evaluation is performed in 3 steps: namely, 0-10 minutes, > 10 minutes to 30 minutes, and > 30 minutes. For the initial 10 minutes, since there is no heat removal by the cooling towers, the basin temperature is calculated using Eq (2). The initial basin temperature, Tb o , is assumed to be 74°F. For time > 10 minutes to 30 minutes, operator actions are taken to turn on the cooling fans and close the bypass valves, However, only partial cooling is available due to one bypass valve failing to close. Eq (1) is then used to calculate the basin temperature. The coefficients A1, D1, and C1, are used for this time period. For time > 30 minutes, full cooling becomes available when operator actions are taken to manually close the failed bypass valve. Eq (1) is also used to calculate the basin temperature, utilizing the coefficients A2, D2, and C2. The output from the MathCAD calculation for this scenario is shown on pages B34 through B40. The maximum basin temperature, Tb,, a ,, is calculated only to be 98.6°F. The temperature at 30 minutes is calculated to be 98.0°F. Both of these values are below the acceptance limit of 100°F. B.7.1.3 Accident Scenario 12 This scenario is the same setup as Scenario 11 with the exception that cells A and B are postulated to be OOS as opposed to cells A and G. The single failure considered for Scenario 12 is the loss of power to Cells E and F bypass basin valve OSX162B and Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 74°F with one SX pump running on each unit. This scenario assumes two tower cells (A and B) are out of service (OOS). Initially, the fans on all the other cells are not running, one bypass valve (OSX162B) is open, and only riser valves to cells A and B are closed. Operator actions are required in the control room to turn on the cooling fans and close the bypass valve within 10 minutes following safeguard signals. Bypass valve OSX162B is assumed to fail to close upon operator actions in the control room (failed bypass valve). This requires manual closing of the bypass valve which is assumed to take 30 minutes after the safeguard signals. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 9 of ATD-0063, Rev. 413 [Ref. B.4.4].

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B12 Since the UHS tower flows are different between the time period before and after the failed bypass valve is closed, two sets of parameters f, Q, M1, B1, M2, 82, a, and R are needed to determine the basin temperature response. The first set is used to calculate the basin temperature for the condition with the failed bypass valve remaining open. The second set is used for the condition with the failed bypass valve closed. For the time period from 10 - 30 minutes after the accident (with operable cooling tower fans at high speed, and the failed bypass valve remains open): The UHS tower flow, based on Scenario 12 (10-30 min) is shown in Design Input 8.2.4, The T hot vs T, o ,d relationship is illustrated in Figure B-5. Determination of f, Q, M1, B1, M2, B2, a, and R. f21 M21. B21 a1 _ Flow through operating cells in T1 Total flow through T1 including bypass flow = 22,029 gpm = 0.922 23,895 gpm F low through operating cells in T2 + Total flow through T2 including bypass flow 5,364 gpm = 0.131 41,060 gpm This is equal to the total flow to T1 and T2, (23,895 + 41,060) gpm = 64,955 gpm Based on an average flow of 11,015 gpm per cell in T1, the tower performance for T1 is generated using a flow of 11,015 gpm (Figure B-5). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(119.98, 91.98), (111.41, 89.41)], Mathcad calculates M11 and B11 from the tower performance inputs. Based on an average flow of 2,360 gpm per cell in T2, the tower performance for T2 is generated using a flow of 6,000 gpm (Figure B-5). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input 8.2.6), [(107.82, 79.82), (100.48, 78.48)], Mathcad calculates M21 and 821 from the tower performance inputs. Flow to T1 _ 23,895 gpm = 0,368 Total SX flow, 0 64,955 gpm CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B13 I 131 : Based on the parameters f, Q, M1, B1, M2, B2, a, and (3 determined above, the coefficients A, B, and C in Eq (1), renamed A1, D1, and C1 here, are calculated for the period from 10 to 30 minutes by Mathcad. For the time period from > 30 minutes after the accident (with the operable cooling tower fans at high speed, and the failed bypass valve is manually closed): The UHS tower flow, based on Scenario 12 (>30 min) is shown in Design Input B.2.4. The T hot vs T co , d relationship is illustrated in Figure B-6. Determination of f, Q, M1, B1, M2, B2, a, and R. f12 f22 M12. B12 M22 B22 (3 is estimated as the fraction of load to T1. __ Flow to RC FC 1A __ (3,172) gpm = 0.530 Flow to RCFC 1 A + Flow to RCFC 1 B (3,172 + 2,816) gpm Flow through operating cells in T1 Total flow through T1 including bypass flow = 24,713 gpm = 0.928 26,626 gpm _ Flow through operating cells in T2 Total flow through T2 including bypass flow 19,813 gpm = 0.521 38,012 gpm This is equal to the total flow to T1 and T2, (26,626 + 38,012) gpm = 64,638 gpm Based on an average flow of 12,357 gpm per cell in T1, the tower performance for T1 is generated using a flow of 12,357 gpm (Figure B-6). Based on the T H , T c values (as determined from the TH values calculated for tower operation in Design Input B.2.6), [(123.57, 95,57), (114.70, 92.70)], Mathcad calculates M12 and B12 from the tower performance inputs. Based on an average flow of 8,995 gpm per cell in T2, the tower performance for T2 is generated using a flow of 8,995 gpm (Figure B-6). Based on the T H , T c values (as determined from the T H values calculated for tower operation in CALCULATION NO. NED-M-MSD-811 REVISION NO. 3, Appendix B PAGE B14 a2: Design Input B.2.6), [(114.83, 86.83), (106.73, 84.73)], Mathcad calculates M22 and B22 from the tower performance inputs. = Flow to T1 = 26,626 gpm = 0.412 Total SX flow, Q 64,638 gpm R is estimated as the fraction of load to T1. _ Flow to RCFC 1A _ (3,144) gpm = 0.530 Flow to RCFC 1 A + Flow to RCFC 18 r (3,144 + 2,790) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (1), renamed A2, D2, and C2 here, are calculated for time > 30 minutes by Mathcad. For this scenario, the basin temperature evaluation is performed in 3 steps: namely, 0-10 minutes, > 10 minutes to 30 minutes, and > 30 minutes. For the initial 10 minutes, since there is no heat removal by the cooling towers, the basin temperature is calculated using Eq (2) of Revision 2. The initial basin temperature, Tb o , is assumed to be 74°F. For time > 10 minutes to 30 minutes, operator actions are taken to turn on the cooling fans and close the bypass valves, However, only partial cooling is available due to one bypass valve failing to close. Eq (1) is then used to calculate the basin temperature. The coefficients A1, D1, and C1, are used for this time period. For time > 30 minutes, full cooling becomes available when operator actions are taken to manually close the failed bypass valve. Eq (1) is also used to calculate the basin temperature, utilizing the coefficients A2, D2, and C2. The output from the MathCAD calculation for this scenario is shown on pages 841 through B47. The maximum basin temperature, Tbma)c, is calculated only to be 99.4°F. The temperature at 30 minutes is calculated to be 99.2°F. Both of these values are below the acceptance limit of 100°F. B.7.1.4 Accident Scenario 13 This scenario is the same setup as Scenario 11 with the exception that cells G and H are postulated to be OOS as opposed to cells A and G. The single failure considered for Scenario 13 is the loss of power to Cells E and F bypass basin valve OSX162B and Cells E and F cooling tower fans. The initial conditions assume a basin temperature of 74°F with one SX pump running on each unit. This scenario assumes two tower cells (G and H) are out of service (OOS). Initially, the fans on all the other cells are not running, one bypass valve (OSX162B) is open, and only riser valves to cells G and H are closed. Operator actions are required in the control room to turn on the cooling fans and close the bypass valve within 10 minutes following safeguard signals.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B15 Bypass valve OSX162B is assumed to fail to close upon operator actions in the control room (failed bypass valve). This requires manual closing of the bypass valve which is assumed to take 30 minutes after the safeguard signals. The total heat load to be used for this scenario is the "Total Heat Load to the UHS" shown in Table 9 of ATD-0063, Rev. 4B [Ref. B.4.4]. Since the UHS tower flows are different between the time period before and after the failed bypass valve is closed, two sets of parameters f, Q, M1, B1, M2, B2, a, and R are needed to determine the basin temperature response. The first set is used to calculate the basin temperature for the condition with the failed bypass valve remaining open. The second set is used for the condition with the failed bypass valve closed. For the time period from 10 - 30 minutes after the accident (with operable cooling tower fans at high speed, and the failed bypass valve remains open): The UHS tower flow, based on Scenario 13 (10-30 min) is shown in Design Input B.2.4. The Thot vs TGdd relationship is illustrated in Figure B-7. Determination off, Q, M1, B1, M2, B2, a, and R. f21 M21. 821 Flow through operating cells in T1 Total flow through T1 including bypass flow 27,985 gpm _ _ - 0.941 29,753 gpm Flow through operating cells in T2 Total flow through T2 including bypass flow = 588 gpm = 0,017 35,512 gpm This is equal to the total flow to T1 and T2, (29,753 + 35,512) gpm = 65,265 gpm Based on an average flow of 6,996 gpm per cell in T1, the tower performance for T1 is generated using a flow of 6,996 gpm (Figure B-7). Based on the T H , T c values (as determined from the TH values calculated for tower operation in Design Input B.2.6), [(110.06, 82.06), (102.46, 80.46)], Mathcad calculates M11 and B11 from the tower performance inputs. Based on an average flow of 2,939 gpm per cell in T2, the tower performance for T2 is generated using a flow of 6,000 gpm (Figure B-7). Based on the T H , T c values (as determined from the T H values calculated for tower operation in CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B16 a1 Design Input B.2.6), [(107.82, 79.82), (100.48, 78.48)], Mathcad calculates M21 and B21 from the tower performance inputs. Flow to T1 _ 29,753 gpm = 0.456 Total SX flow, Q 65,265 gpm R is estimated as the fraction of load to T1. Flow to RCFC 1 A (3,201) gpm - = 0.530 Flow to RCFC 1 A + Flow to RCFC 1 B (3,201 + 2,839) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and R determined above, the coefficients A, B, and C in Eq (1), renamed A1, D1, and C1 here, are calculated for the period from 10 to 30 minutes by Mathcad. For the time period from > 30 minutes after the accident (with the operable cooling tower fans at high speed, and the failed bypass valve Is manually closed): The UHS tower flow, based on Scenario 12 (>30 min) is shown in Design Input B.2.4. The Trot vs Ted relationship is illustrated in Figure B-8. Determination of f, Q, M1, B1, M2, B2, a, and ¢. f12 f22 M12 S B12 Flow through operating cells in T1 Total flow through T1 including bypass flow = 36,159 gpm = 0.953 37,956 gpm F low through operating cells in T2 Total flow through T2 including bypass flow = 2,482 gpm = 0.093 26,714 gpm This is equal to the total flow to T1 and T2, (37,956 + 26,714) gpm = 64,670 gpm Based on an average flow of 9,040 gpm per cell in T1, the tower performance for T1 is generated using a flow of 9,040 gpm (Figure B-8). Based on the T H , T c values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(114.94, 86.94), (106.83, 84.83)], Mathcad calculates M12 and B12 from the tower performance inputs.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B17 M22, B22 a2 Based on an average flow of 12,412 gpm per cell in T2, the tower performance for T2 is generated using a flow of 12,412 gpm (Figure B-8). Based on the T H , T C values (as determined from the T H values calculated for tower operation in Design Input B.2.6), [(107.82, 79.82), (100.48, 78.48)], Mathcad calculates M22 and B22 from the tower performance inputs. Flow to T1 _ 37,956 gpm = 0.587 Total 5X flow, Q 64,670 gpm (3 is estimated as the fraction of load to T1. __ Flow to RC FC 1A __ (3,149) gpm = 0.530 Flow to RCFC 1 A +Flow to RCFC 1 B (3,149 + 2,791) gpm Based on the parameters f, Q, M1, B1, M2, B2, a, and [3 determined above, the coefficients A, B, and C in Eq (1), renamed A2, D2, and C2 here, are calculated for time > 30 minutes by Mathcad. For this scenario, the basin temperature evaluation is performed in 3 steps: namely, 0-10 minutes, > 10 minutes to 30 minutes, and > 30 minutes. For the initial 10 minutes, since there is no heat removal by the cooling towers, the basin temperature is calculated using Eq (2). The initial basin temperature, Tb o , is assumed to be 74°F. For time > 10 minutes to 30 minutes, operator actions are taken to turn on the cooling fans and close the bypass valves, However, only partial cooling is available due to one bypass valve failing to close. Eq (1) is then used to calculate the basin temperature. The coefficients A1, D1, and C1, are used for this time period. For time > 30 minutes, full cooling becomes available when operator actions are taken to manually close the failed bypass valve. Eq (1) is also used to calculate the basin temperature, utilizing the coefficients A2, D2, and C2. The output from the MathCAD calculation for this scenario is shown on pages B48 through B54. The maximum basin temperature, Tbma, , is calculated only to be 99.2°F. The temperature at 30 minutes is calculated to be 97.0°F. Both of these values are below the acceptance limit of 100°F.

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B 1 8 8.0 RESULTS AND CONCLUSIONS The results for Scenarios 10 through 13 are summarized below. Table 8.1 - Summary of Scenarios The additional scenarios 10 through 13 for postulated single failures of electrical breakers serving the SX system components occurring concurrent with a LOCA and a LOOP on one unit with the opposite unit in normal shutdown as described in UHS-04 [Ref. B.4.3] remain below 100°F. Per the Table 8.1 above, Scenarios 10 through 13 meet the acceptance criteria of the basin temperature being less than 100°F. Scenario 12 is the bounding scenario in terms of maximum basin temperature. Scenarios 10 through 13 account for valve leakby and power uprate heat load. The overall conclusions made in NED-M-MSD-011, Revision 2 continue to be valid. It can be concluded that at an initial basin temperature of 74°F and an initial basin volume of 59% (or 40,578 ft 3 per basin volume; 3,312 ft 3 of silt is subtracted from this volume for the calculation), the basin temperature under various design basis accident scenarios remains below the acceptance criteria value of 100°F. Limitation This conclusion is based on the assumption that the failed open bypass valve can be closed in 30 minutes after the safeguards signals. Cells Tb (°F) b Scenario OOS Description at 30 M (F) minutes 10 A and G Initially All Bypass Valves Open 96.6 98.4 and All Riser Valves Closed at 50 min 11 A and G Initially OSX162B Open, Only Riser 98'0 98.6 Valves to A and G are Closed at 40 min 12 A and B Initially OSX162B Open, Only Riser 99'2 99.4 Valves to A and B are Closed at 36 min 13 G and H Initially OSX162B Open, Only Riser 97" 0 99.2 Valves to G and H are Closed at 53 min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B19 105 100 95 90 80 75 70 Figure B-1: Scenario 10, 10-30 minutes 80 90 100 110 120 130 140 Tnoc (OF)

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B20 1 130 125 120 100 95 90 85 80 Figure B-2: Scenario 10, >30 minutes 90 100 110 120 130 140 150 160 170 Thot ('F)

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B21 105 100 95 90 80 75 70 ~ I 80 90 100 Figure B-3: Scenario 11, 10-30 minutes 110 That (0 F) 11(1) Tower A, 8608 gpm, Twb 70°F - - -11(1) Tower B, 6000 gpm, Twb 70°F {

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B22 I 100 95 90 80 75 70 Figure B-4: Scenario 11, >30 minutes 11(2) Tower A, 10157 gpm, Twb 70°F 80 90 100 110 120 130 140 Tnot ('F)

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B23 Figure B-5: Scenario 12,10-30 minutes 12(1) Tower A, 11015 gpm, Twb 70°F - - -12(1) Tower B, 6000 gpm, Twb 70°F E CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B24 105 100 95 - 85 80 70 Figure B-6: Scenario 12, >30 minutes 80 90 100 110 120 130 140 150 Tnoc ('F) E Tower A, 12357 Twb 70°F i 12(2) gpm, - - -12(2) Tower B, 8995 gpm, Twb 70°F I i I I F , . i f CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B25 Figure B-7: Scenario 13,10-30 minutes 80 90 100 110 120 130 140 Tnuc (°F)

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B26 105 100 95 85 80 75 70 Figure B-8: Scenario 13, >30 minutes 80 90 100 110 120 130 140 150 Tnoc (`F)

CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E $-c-enario-10 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN=- 1 in=- I L lbm = 1 M F = 1 Q sec --- 1 T gpm := g a l ~.= lbm-F MBTU := BTU-10 min Cooling Tower Performance Thl :_ Th2 := -F -F Th3 _ C113.28 122.91 ).F TO _ (94.28).F Th4 :_ 119.52 (112.88).F Tc4 :_ 99 88 (103.52 ).F 115.05 87.05 (106.94 -F Tcl := 84.94 79.82 107.82) F Tc2:= 78.48 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page B2F Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 L2:= 844 MBTU T2:= 18.32 min 823 , hr 19.98 804 21.65 786 23.32 701 29.98 592 39.98 526 49.98 503 59.98 430 83.32 379 116.65 279 166.65 239 333.32 234 480.00 543 480.17 536 540.00 530 600.00 528 627.50 525 660.00 464 660.17 458 732.00 438 732.17 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E SX System Flow rate Q 1 := 65046. gpm (Total flow to T1 and T2 gpm) Q2:= 63606 . gpm (Total flow to Ti and T2 gpm) Basin Mass V := 1.06810 6 gal (Design Input B.2.2) p := 8.33. lbm Mb := P' V Cp := I. BTU M b = 8.9 x 10 6 1bm gal F. lbm Fans (Active/Total) Time Constant fl l := 0.938 f12 := 0.956 121 := 0.15 f22:= 0.901 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.447 a2 := 0.678 /31 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tcl) 1311 := intercept(Th1,Tc1) M12 := slope(Th3,Tc3) B12:= intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22:= slope(Th4,Tc4) B22:= intercept(Th4,Tc4)

M11=0.26 1311=57.117F M12=0.377 B12=51.579F M21 = 0.183 B21 = 60.136 F M22 = 0.548 B22 = 38F CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Calculate Intermediate Constants - al-[(1 - f11) + f11 M1II -(I - a1)-(1 - l2l + f21.M21)] A l := A2 := D1 : (31.(1 - fl 1 + f11-M11) + (1 - R1).(l - f2l + f2l.M21) _ D2 := (32.(l - f12 + f12-M12) + (1 - [32).(1 - f22 + f22.M22) M b'C P Cl := Q1. al'fl1-Bl l + (1 - al)421-B21 V C2:= Q2 a2-f12-B12

+ (1 - a2)-f22.B22 ~ V Al=-0.021 D1 =6-46x 10 8 F F A2=-0.03 1 D2 =5.54x 10 8 F F min BTU C2 = 2.65 - Integrating to Solve for Basin Temperature (Initial Basin Temperature, Tb is 74°F) Ub l := 74-F i:= 1_99 H:= A-min st i := i-H linterp(T2 , L2, st) I M b-C P i = 100..299 1 -min st.:= i-H ~w ,I'= ' t Ub i+1 := Ubi + [(AI.Ubi) + (linterp(T2, L2, st) .D1) + (C1)J-H use uprate heat load i - 300..2400 l ~ -min St. := i-H nN iv1r'- ' t + C (A2.Ubi) + (linterp(T2,L2,st i)-D2) + (C2)1.H use uprate heat load (__Q2 V .[] - a2 j(1 - f12) + f12.M12J - (1 - a2).(1 - f22 + f22.M22)] M b-C P min BTU C1 = 1.76 min .H min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Results 107 102.38 97.75 93.13 o Ub i 88.5 83.88 79.25 74.63 index := index = 98.35 F st. index = 3006 see ,w= 1,20-7000 70 0 2000 4000 6000 8000 1.10 4 1.2-10 4 st i Basin Temperature Response vs. Time (sec) use uprate heat load maximum:= maximum f- 0 for i e 300-2400 max(Ub) = 98.35 F @ t = 50.1 min maximum F- max(Ub. i 300 = 96.6 F 100 = 86.5 F maximum= 98.35 F index F-- 0 maximum F-- 0 for i c 300.. 2400 if max( index = 501 i) >_ maximu maximum E- max(Ub i) if max(Ub i) >_ maximum index <- i if max(Ub i) >_ maximum CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Basin Temperature and UHS Heat Load vs. Time Ub. F linterp(T2 , L2, st.) MBTU hr i = lVV 1,26..1000 St. t min 74 83 0.1 77.19 713.29 2.6 80.46 680.85 5.1 83.59 658.04 7.6 86.56 639.21 10.1 87.96 922.62 12.6 89.69 888.28 15.1 91.24 853.49 17.6 92.61 821.63 20.1 93.83 793.76 22.6 94.9 763.28 25.1 95.83 731.38 27.6 96.62 699.69 30.1 97.11 672.44 32.6 97.5 645.19 35.1 97.8 617.94 37.6 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E 1000 800 600 C fnter~T2, L2, st;) MBT U) hJJJr 400 200 ,~;= 1,20-6000 1000 2000 3000 4000 5000 6000 st i Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and G OOS ORIGIN =- t in = 1 L Ibm = 1 M F = 1 Q sec --- 1 T gpm := g a l lbm-F MBTU := BTU-106 min Cooling Tower Performance

113.871 85.87 Th l := -F Tc1:= 083 T X105.88) .88 107.82 79.82 Th2 := F Tc2:= T 100.48 X78.48) 89.76 Th3 := 117.76) T Tc3 := (87.38 T 117.77 89.77 Th4 := T Tc4 := -F 109.39 87.39 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Uz)rate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBT'U 18.32 L2:= T2:= -min 823 . hr 19.98 804 21.65 786 23.32 701 29.98 592 39.98 526 49.98 503 59.98 430 83.32 379 116.65 279 166.65 239 333.32 234 480.00 543 480.17 536 540.00 530 600.00 528 627.50 525 660.00 464 660.17 458 732.00 438 732.17 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E SX System Flow rate Q l := 65160.gpm (Total flow to T1 and T2 gpm) Q2:= 64766. gpm (Total flow to T1 and T2 gpm) Basin Mass V := 1.068 10 6. gal (Design Input 8.2.2) p := 8.33. lbm Mb := P- V cp.= 1. BTU M b = 8.9 x 10 6 1bm gal F- lbm Fans (Active/Total) Time Constant fl l := 0.935 f12 := 0.943 f21 := 0.065 f22 := 0.376 V V T1 := - T2 := Q1 Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.424 a2 := 0.499 01 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Thl,Tc1) B11 := intercept(Thl,Tc1) M12 := slope(Th3,Tc3) B12 = intercept(Th3,Tc3)

M21 := slope(Th2,Tc2) B21 := intercept(Th2,Tc2) M22 := slope(Th4,Tc4) B22 := intercept(Th4,Tc4)

Ml 1 = 0.249 B11 = 57.509F M12 = 0.284 B12 = 56.315 F M21 = 0.183 B21 = 60.136 F M22 = 0.284 B22 = 56.322 F CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Calculate Intermediate Constants r 01 Al := l V A2 := - al-[(1 - fl l) + fl 1-M11] - -[1 - a2 j(1 - f12) + f12-M12] - Dl := /31'(1 - fll + f11.M11) + (l - [ll)-(1 - f21 + f21.M21) D2 := (32.(l - f12+ f12-M12) + (1 - X32)-(1 - f22+ f22.M22) M b'C P a1-f11.B11 + (l - al)421-B21 V M b'C P C2:= Q2. a2-f12-B12

+ (l - a2)-f22.B22 V Integrating to Solve for Basin Temperature (Initial Basin Temperature, Tb is 74°F) Ub l := 74-F i:= 1.. 99 H:= .l -min st i := i-H "linterp(T2, L2, st i) M b- C P = 100.. 299 + [(AI-Ubi)

+ (linterp(T2,L2,st i) -D1) + (C1)]-H use uprate heat load w= 300.. 2400 a:= A-min st i := M i+1 := Ubi + [(A2.Ub i) + (linterp(T2,L2,st i).D2) + (C2)1.H use uprate heat load .= .1 -min -H st i := i-H (1 - al)-(1 - f21 + f21-M21)]

(1 - a2)-(1 - f22 + f22-M22)]

Al=-0.02 1 min D1 F =6.78x 10 8 BTU C1 F = 1.53 min A2=-0.03 1 min F D2=5.8x 10-8 BTU C2 = 2.25 F min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Results 107 102.38 97.75 93.13 o Ubi 88.5 83.88 79.25 74.63 use uprate heat load maximum := I maximum <-- 0 for i e 300.. 2400 maximum <-- max(Ub.l \ 1i 70 0 2000 4000 6000 8000 110 4 1.210 4 sti max(Ub) = 98.6 F @ t = 40.2 min 0 = 98F = 86.5 F index := index = 98'6 F st index . = 2412 see ~= 1,20-7000 Basin Temperature Response vs. Time (sec) maximum= 98.6 F if max( index F- 0 maximum F- 0 for i E 300.. 2400 1 maximum <- max(Ub i) if max(Ub i) >_ maximum index <- i if max(Ub i) >_ maximum index = 402 i) >_ maximu CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Basin Temperature and UHS Heat Load vs. Time Ub i F linterp(T2, L2, st.) MBTU hr = 1, 26.. 1000 St. min 74 83 0.1 77.19 713.29 2.6 80.46 680.85 5.1 83.59 658.04 7.6 86.56 639.21 10.1 88.13 922.62 12.6 90.05 888.28 15.1 91.78 853.49 17.6 93.33 821.63 20.1 94.73 793.76 22.6 95.97 763.28 25.1 97.07 731.38 27.6 98.01 699.69 30.1 98.27 672.44 32.6 98.46 645.19 35.1 98.56 617.94 37.6 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E ,~= 1, 20.. 6000 5t; Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Scenario 12 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells A and B OOS ORIGIN = I in -= I L lbm --= 1 M F =- 1 Q sec --- I T gpm := g a l lbm-F MBTU := BTU-106 min Cooling Tower Performance Thl := (119.48).F Tcl := (91.98)-F Tn2:_ `107.82) 100.48 , -F Tc2:= (79.82) X78.48 .F Th3 :_ (112314.57.70).F Tc3 _ (92 95.70.57) .F Th4:_ (110614.73.83).F Tc4:_ (84.773).F CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Uorate Heat load (L42) L2 := 83 83 769 760 749 724 721 718 715 701 682 666 652 640 630 934 914 890 866 844 823 804 786 701 592 526 503 430 379 279 239 234 543 536 530 528 525 464 458 438 MBTU hr T2 := 0.00 0.17 0.35 0.50 0.75 2.00 2.17 2.33 2.50 3.32 4.98 6.65 8.32 9.98 11.50 11.65 13.32 14.98 16.65 18.32 19.98 21.65 23.32 29.98 39.98 49.98 59.98 83.32 116.65 166.65 333.32 480.00 480.17 540.00 600.00 627.50 660.00 660.17 732.00 732.17 min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E SX System Flow rate Q 1 := 64955 . gpm (Total flow to T1 and T2 gpm) Q2 := 64638 " gpm (Total flow to TI and T2 gpm) Basin Mass V := 1.068 10 6 gal (Design Input 8.2.2) p := 8.33. lbm Mb ._ P- V C p := I . BTU Mb = 8-9 x 10 6 Ibm gal F- Ibm Fans (Active/Total) Time Constant fl l := 0.922 f]2:= 0.928 f21 := 0.131 f22:= 0.521 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.368 a2 := 0.412 01 := 0.53 (32 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 MI I := slope(Thl,Tcl) 1311 := intercept(Thl,Tcl) M12 := slope(Th3,Tc3) B12 := intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22:= slope(Th4, Tc4) B22 := intercept(Th4, Tc4) MI 1=0.3 1311=56F M12=0.324 B12=55.587F M21 = 0.183 B21 = 60.136F M22 = 0.259 B22 = 57.059 F CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page B Calculate Intermediate Constants A 1 :_ A2 := (-Q).CI - a2.[(1 - fl2) + f12-M12] - (l - a2).(1 - f22+ f22-M22)]

D 1 := D2 := C1 := Q1 a1-f11-B11

+ (1 - a1).f21.B21 ~ V C2:= Q2 a2412-B12

+ (1 - a2)-f22-B22 V Al=-0.02 1 D1 =6.83x 10 8 F min BTU A2 = -0.03 1 D2 = 5.46 x 10 8 F min BTU Integrating to Solve for Basin Temperature (Initial Basin Temperature, Tb Is 74°F) (31-(1-flI+f11-MI1)+(1-[31-(1-f21+f21.M21) (32.(1 - f12+ f12-M12) + (I - [32-(1 - f22+ f22-M22) .= 74-F 100.. 299 2V .1 -min st i := i-H + [(AI-Ub) + (linterp(T2,L2,st i).DI) + (Cl)]-H use uprate heat load = 300-2400 1a:= .1-min st i := i - H il + (Iinterp(T2,L2,st i).D2) + (C2)1.H use uprate heat load Q1 ).[I - al -[(1 - fl l) + f11-M11] - (l - al).(1 - f21 + f21-M21)]

Ub i+1 '= Ub i + RA2. M b-C P i:= 1..99 H:= A-min st. i-H t linterp(T2, L2, st i , i+1 '= Ub i + ~H Mb. Cp Mb. Cp C 1 = 1.46 F min C2 = 2.34 F min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page 6 Results 107 102.38 97.75 93.13 o Ub; 88.5 83.88 79.25 74.63 70 M;= 1,20.. 7000 0 2000 4000 6000 8000 1.10 4 1.2-10 4 St; use uprate heat load maximum:= maximum F-- 0 for i e 300-2400 max(Ub) = 99.43 F @ t = 36.1 min maximum E-- max(Ub i) if max(Ub i~ >_ maximu Ub 300 = 99.2 F Basin Temperature Response vs. Time (sec) = 86.5 F maximum = 99.43 F index := index = 9943 F St index i = 2166 sec index F- 0 maximum F- 0 for i e 300.. 2400 I maximum F- max(Ub i) if max(Ub i) >_ maximum index E- i if max(Ub i) >_ maximum index = 361 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page B Basin Temperature and UHS Heat Load vs. Time Ub. F linterp' T2, L2, st i) MBT U hr ~= 1,26.. 1000 St. min 74 83 0.1 77.19 713.29 2.6 80.46 680.85 5.1 83.59 658.04 7.6 86.57 639.21 10.1 88.29 922.62 12.6 90.37 888.28 15.1 92.26 853.49 17.6 93.97 821.63 20.1 95.52 793.76 22.6 96.92 763.28 25.1 98.17 731.38 27.6 99.24 699.69 30.1 99.36 672.44 32.6 99.42 645.19 35.1 99.42 617.94 37.6 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E 1000 800 600 Iinter~T2, L2, sti) MBT U) hr 400 200 ,w= 1,20-6000 1000 2000 3000 4000 5000 6000 sti Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Scenario 13 Two Tower Model - (Heat load for Power Uprate) Breaker Failure (Loss of power to Cells E and F) with Cells G and H OOS ORIGIN = t in=- 1 L Ibm =_ 1 M F = 1 Q sec=- 1 T gpm := g a l := Ibm-F MBTU := BTU. 106 min Cooling Tower Performance

Thl :_ (1 1 02 10.46.06) F Tcl _ (8082.46.06 )-F 107.82) 79.82 Th2 :_ 100.48) ) -F Tc2 :_ -F X78.48 114.94 Th3 := (106.83 -F TO := 86.94) ) .F 123.71 95.71) Th4 := -F 114.84 Tc4 := 92.84) ) ~F CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Uprate Heat load (L42) 83 0.00 83 0.17 769 0.35 760 0.50 749 0.75 724 2.00 721 2.17 718 2.33 715 2.50 701 3.32 682 4.98 666 6.65 652 8.32 640 9.98 630 11.50 934 11.65 914 13.32 890 14.98 866 16.65 844 MBTU 18.32 L2:= T2:= min 823 , hr 19.98 804 21.65 786 23.32 701 29.98 592 39.98 526 49.98 503 59.98 430 83.32 379 116.65 279 166.65 239 333.32 234 480.00 543 480.17 536 540.00 530 600.00 528 627.50 525 660.00 464 660.17 458 732.00 438 732.17 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E SX System Flow rate Q 1 := 65265.gpm (Total flow to T1 and Tz gpm) Q2:= 64670. gpm (Total flow to Ti and Tz gPm) Basin Mass V := 1.068-10 6. gal (Design Input B.2.2) p := 8.33. lbm Mb := P- V c p := 1- B TU Mb = 8.9 x 10 6 1bm gal F-lbm V Q2 Fraction of flow to Tower 1 Fraction of heat load to Tower 1 al := 0.456 (x2:= 0.587 (31 := 0.53 02 := 0.53 Find Slopes and Intercepts of cooling towers 1 and 2 M11 := slope(Th1,Tc1) 1311 := intercept(Thl,Tc1) M12 := slope(Th3,Tc3) B12:= intercept(Th3,Tc3)

M21 := slope(Th2, Tc2) B21 := intercept(Th2, Tc2) M22 := slope(Th4, Tc4) B22 := intercept(Th4, Tc4) M11 = 0.211 B11 = 58.889F M12 = 0.26 B12 = 57.036F M21 = 0.183 B21 = 60.136 F M22 = 0.324 B22 = 55.682 F Fans (Active/Total)

Time Constant V fl 1 := 0.941 fl2 := 0.953 Ql 1`21 := 0.017 f22:= 0.093 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Calculate Intermediate Constants A l := A2:= Ql V D1 :_ /31-(1-fll+01-M11)+(1-01)

.(1-f21+f21.M21) M b'C P D2 :_ (32.(1 - f12 + f12M12) + (1 - i32)-(1 - f22 + f22-M22) M b-C P C1 := Q1. al-f11-B11

+ (1 - a1)-f2VB21 V Integrating to Solve for Basin Temperature (Initial Basin Temperature, Tb is 74°F) Ub l := 74-F i := 1 .. 99 H:= A -min linterp(T2, L2, st t.)1 l st. := i-H t .H M b- C P ;= 100.. 299 1U:= .1 -min St i := i-H i+1 := Ubi+ [(Al -Ub i) + (linterp(T2,L2,st i)-D1) + (C1)1.H use uprate heat load = 300..2400 1a:= A-min st i := i-H i+1 := Ubi + C (A2-Ub i) + (Iinterp(T2,L2,st i) -D2) + (C2)1-H use uprate heat load - CO 40 - fl l) + f11-M11] - (1 - al)-(1 - f21 + f21-M21)1 - a2.[(1 - f12) + f12-M12] - (1 - a2).(1 - f22 + f22.M22)1 - C2:= Q2 a2-f12-B12

+ (1 V a2).f22-B22 A 1 = -0.02 1 min D 1 = 6.74 x 10 8 F BTU C1 = 1.58 F min A2=-0.03 1 min D2=6.71 x 10 8 F BTU C2 = 2.06 F min CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Results 107 102.88 98.75 94.63 o Ub; 90.5 86.38 82.25 78.13 74 Ub300 = 97F Ub 100 = 86.5 F ,w= 1,20..7000 0 2000 4000 6000 8000 1.10 4 1.2 -1 0 4 St; Basin Temperature Response vs. Time (sec) use unrate heat load maximum := maximum F- 0 for i e 300-2400 max(Ub) = 99.24 F @ t = 52.5 min maximum E-- max(Ub i~ index := index = 99.24 F St . index = 3150 see maximum= 99.24 F if max( index +- 0 maximum E-- 0 for i e 300.. 2400 1 maximum F-- max(Ub i) if max(Ub i) > maximum index F- i if max(Ub) >_ maximum index = 525 J >_ maximu CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E Basin Temperature and UHS Heat Load vs. Time Ub i F Iinterp(T2 , L2, st i) MBTU hr ~= 1, 26.. 1000 St i min 74 83 0.1 77.19 713.29 2.6 80.46 680.85 5.1 83.59 658.04 7.6 86.56 639.21 10.1 87.99 922.62 12.6 89.78 888.28 15.1 91.38 853.49 17.6 92.81 821.63 20.1 94.08 793.76 22.6 95.21 763.28 25.1 96.19 731.38 27.6 97.03 699.69 30.1 97.63 672.44 32.6 98.11 645.19 35.1 98.48 617.94 37.6 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B Page E 1000 800 600 linter~T2, L2, st;) MBTU) 400 200 M;- 1,20.. 6000 1000 2000 3000 4000 5000 6000 st; Post LOCA Time (sec) UHS Accident Heat Load Profile L42 CALCULATION NO. NED-M-MSD-011 REVISION NO. 3, Appendix B PAGE B55 A rcsrugh a~ Hope that helps. sa*rt@dt.%Q ,t. n1:esPhi aid art 5>>,%1e x:74 t=ea TO M>~:~~-AELA NEf;A, sarge.~xktttfil-atn

.NDRS0V.A CARMEANr4swqWtundycom ea Re: `Aectiancral Drafz C_xwq TowwPerfanr e 4Yi tr,aerat;+e fans would like data based on a specific tovict se4c6an l cars offer clearer expectacoo P Pegional Sales M~ayier. We Coadrig Products 5PX Ccoiirsg Techr" o4Nies 4141 S:acevsew Crescent-Uno 13, Mississatnga, Ore Canada LSL 5T1 7 el: +1 905 607 5446 ex% 343, Cell: +1 305 4f,4 E433, Fax: +1 913 693 9332, E-Mali vaul.secest~z~ct spx.ce~m ne w{nmtatitx, mctamed in this L4e--mr ^.c n:aiil tsansmiss" ,on :s intended b:., SPX Corpcratim far the use of the named .rdwiduai or er,6rr to wh,ch it is dirsc-rd and rna, vo-,taitn irfor-motor that is cor&-denval or prrileged. 1f ";ate have received tfiis electronic mail transmission in enter, plea=ts dciete it from ; ct~r .,_;stet :without COP; ir'g or f~ardtng ~t. ono notify tt,e sender of the error b;: repl;" emad sa that tl~e sender's .r hf.'f?R£ W /t C SFRtEAtdl9satnr_

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~:. ~s Paul - In, acs earlier vis~'t rn S&L vie briefly dismissed the estlrraCed peff¬tx"anoe of a - pioat meCksanicai draft Wet =o1ing tower WAh the fan inoperable. We are doing an arzal, sis for EK41on's &," foot Station to evahcate post-accident soc4ing rawer basin ternperxtxes. considering fashuns of some fans to operate due to postcard single failures. tarna~do issi es. etc. For srnr'>e scrnstios, we want to credit sflrne limited ac-,amt of ccuhng :~a~,+atlrair, f inactive cell fan riot operadnagj wins wa er still being de4verad to ?fiat cell. Can , ot. give us , our best estimate as ro vrftat ::knd of performance one could eup--ct from, an tnac-trve rT,achan~-al craft wee coolrra tower i e.g.. pervert of nom,ai fell cr'-:::+rg ~-apacxt; t ? I recall ,flu ntendonsrd d,at SPX mad have some enfurmatron. iterawre, Cr aast per?ur^-:a^ce start ate s , ,~ch an estmate. Is +:s information avaVabte or prcpretan) zn ATTACHMENT 8 Simplified Drawings of Scenarios 10, 11, 12, and 13 Simplified_

Drawings of Additional Scenarios Scenarios 10 through 13 OOS--~°WER B H 22 0-0 SCENARIO 1e POST LOCA CONFIGURATION (t-10 min. t o 30 min.) OOS 28 18 2A 1A J x x x 28 18 v x x 1A 2A RCFC RCFC U U U RCFC RCFC N t9 M~ G A FAILED FAILED OPEN* TOWER A

BYPASS VALVE IS ASSUMED TO BE MANUALLY CLOSED AT t=30 minutes.

2B 1B 2A 1A x x x 2B 1B v ~ 1A 2A RCFC RCFC ~ m v RCFC RCFC M~ G 22 a0 A OOS--SOWER B H SCENARIO 11 POST LOCA CONFIGURATION (t-10 min. t o 30 min.) OOS FAILED ) TOWER A B C D 11 21 21 00 c X0 00 FAILED OPEN*

BYPASS VALVE IS ASSUMED TO BE MANUALLY CLOSED AT t=30 minutes.

H G 22 22 00 C>0 SCENARIO 12 POST LOCH CONFIGURATION (t=10 min. t o 30 min.) TOWER B OOS T-T- x x x 2B 1B ~ ~ ~ 1A 2A RCFC RCFC v v v RCFC RCFC N FAI B~ 11 C>> 4 00 FAILED FAILED OPEN C D 21 21 00 C>4

BYPASS VALVE IS ASSUMED TO BE MANUALLY CLOSED AT t=30 minutes.

OOS SCENARIO 13 POST LOCA CONFIGURATION (t---10 min. t o 30 min.) x 2B 1B X v U 1A 2A RCFC RCFC U U U RCFC RCFC N 6i M~ lwwalwl G FAILED TOWER A FAILED OPEN* A B C D 11 11 21 21 BYPASS VALVE IS ASSUMED TO BE MANUALLY CLOSED AT t=30 minutes.

ATTACHMENT 9 Summary of Regulatory Commitments The following list identifies those actions committed to by Exelon Generation Company, LLC, (EGC) in this submittal. Any other actions discussed in the submittal represent intended or planned actions by EGC, are described only for information, and are not regulatory commitments. COMMITMENT TYPE ONE-TIME PROGRAM- ACTION MATIC COMMITTED DATE COMMITMENT OR "OUTAGE" (YES/NO) (YES/NO) EGC will revise appropriate Upon implementation of No Yes procedures to ensure procedural the proposed change guidance is put in place to direct operators to shed heat load during a loss-of-coolant accident, under the most severe design basis weather conditions (i.e., maximum air wet bulb temperature), with a breaker failure that results in the loss of two Essential Service Water cooling tower fans.

v t e Letter Sequence Request
TAC:ME1669, (Approved, Closed)
Initiation Request, Request, Request, Request, Request Acceptance... Supplement Administration Meeting Questions 16 December 2010 11 December 2009 18 May 2010 18 August 2010 2 November 2010 28 December 2010 14 February 2011 10 March 2011 Answers 31 January 2011 Results Approval Other: ML092120357
MONTHYEAR2010-05-18 [Table View]

ML091831253

Text

Subject:

SUMMARY

2.0 DETAILED

3.0 TECHNICAL

4.0 REGULATORY EVALUATION

4.1 Applicable

4.2 Precedent

4.4 Conclusion

5.0 ENVIRONMENTAL

6.0 REFERENCES

SUMMARY

4.0 REGULATORY EVALUATION

4.1 Applicable

6.0 REFERENCES

3.7 PLANT

7.9 BACKGROUND

4.0 REFERENCES

3.1 Verification

3.1 states

4.0 REFERENCES

4.1 Ceramic

Reference:

4.0 REFERENCES

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