ML13029A456

Emergency License Amendment Request: Revise Description of Operable Containment Air Cooling Train

ML13029A456
Person / Time
Site:	Calvert Cliffs
Issue date:	01/22/2013
From:	Flaherty M Calvert Cliffs, Constellation Energy Nuclear Group, EDF Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13029A456 (167)

Text

Calvert Cliffs Nuclear Power Plant, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.5200 410.495.3500 Fax CENG.

a joint venture of En-ýr DF CALVERT CLIFFS NUCLEAR POWER PLANT January 22, 2013 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Emergency License Amendment Request: Revise Description of Operable Containment Air Cooling Train In accordance with 10 CFR 50.90, Calvert Cliffs Nuclear Power Plant, LLC is submitting a request for an emergency amendment to add a License Condition to restrict operating parameters related to a degraded Containment Air Cooling train for Calvert Cliffs Nuclear Power Plant Unit 2. The proposed License Condition would revise the description of an operable Containment Air Cooling train for Unit 2 in Appendix C of Renewed Operating License DPR-69.

On Unit 2, No. 24 Containment Air Cooler fan motor became grounded and was declared inoperable at 0349 on Saturday, January 19, 2013. Technical Specification 3.6.6 Required Action C was entered with a Completion Time of 7 days to restore the Containment Air Cooling train to operable status. This Completion Time expires on Saturday, January 26, 2013 at 0349. Condition E would then be entered which requires the Unit be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The potential cause of the grounded fan motor is a premature winding failure. This fan motor is unique to the No. 24 Containment Air Cooler fan since it was manufactured in 2008 and installed in 2009. The remaining Containment Air Cooler fan motors are all older generation motors which have been rewound in accordance with the Maintenance Program. The grounded fan motor must be replaced, which can only be done during a Unit 2 outage. Additionally, Unit 2 is scheduled to shutdown for a refueling outage on February 17, 2013. Entry into Mode 4 is currently scheduled for 1800 on February 17, 2013. Failure to address the inoperable containment air cooler fan motor in a timely manner will result in the unscheduled shutdown of Unit 2.

Attachment (1) provides a description and assessment of the proposed change. Two evaluations have been performed to support changing the definition of an operable Containment Air Cooling train to exclude the No. 24 Containment Air Cooler fan. The evaluations are included as Enclosures 1 and 2.

Document Control Desk January 22, 2013 Page 2 Calvert Cliffs Nuclear Power Plant requests approval of the proposed license amendment by 1800 on January 25, 2013'. A decision on this license amendment request is needed by this time to allow implementation activities to be completed prior to the expiration of the Required Action Completion Time on Saturday, January 26, 2013 at 0349.

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

There are no regulatory commitments contained in this letter.

Should you have questions- regarding this matter, please contact Mr. Douglas E. Lauver at (410) 495-5219.

I declare under penalty of perjury that the foregoing is true and correct. Executed on January 22, 2013.

Mark D. Flaherty Plant General Manager MDF/PSF/bJd Attachments: (1) Description and Assessment of Proposed Changes Enclosure 1- CCNPP Containment Response to Loss of One CAC Unit Enclosure 2- Containment Response Analysis in Support of CCNPP Units 1 & 2LAR

Document Control Desk January 22, 2013 Page 3 cc: N. S. Morgan, NRC Resident Inspector, NRC W. M. Dean, NRC S. Gray, DNR

ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES TABLE OF CONTENTS 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

3.0 TECHNICAL EVALUATION

4.0 REGULATORY SAFETY ANALYSIS

5.0 ENVIRONMENTAL CONSIDERATION

Calvert Cliffs Nuclear Power Plant, LLC January 22, 2013

ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES 1.0

SUMMARY

DESCRIPTION This letter is a request for an emergency amendment to Renewed Operating License DPR-69 for Calvert Cliffs Nuclear Power Plant (Calvert Cliffs), Unit 2 to add a License Condition to restrict operating parameters related to a degraded Containment Air Cooling train.

2.0 DETAILED DESCRIPTION

System Description

The function of the Containment Air Cooling system is to remove heat from the containment atmosphere during normal plant operation. In the event of a loss-of-coolant accident (LOCA), the system functions to limit the containment pressure rise to a level below the design value. In such an instance, the system also functions to reduce the leakage of airborne and gaseous radioactivity by providing a means of cooling the containment atmosphere.

The Containment Air Cooling system is independent of the Containment Spray system. It is sized such that, following a LOCA, three of the four cooling units will limit the containment pressure to less than the containment design pressure even if the Containment Spray system does not operate.

The Containment Air Cooling system includes four two-speed cooling units located entirely within the Containment. Service water is circulated through the air cooling coils. Air is drawn through the coils by a vane-axial fan driven by a direct coupled two-speed motor. Normal containment recirculation requirements are satisfied at high speed operation, whereas, after a LOCA, the low speed setting is used.

All fan motors may be manually started or stopped from the Control Room. Upon occurrence of a LOCA, all four fan motors start automatically upon receipt of a Safety Injection Actuation Signal.

Normal Operation Three cooling units are normally in operation. Each unit is sized to remove in excess of one-third of the total normal cooling load. The maximum average temperature inside the Containment is limited to 120'F by operation of the three cooling units. The maximum expected service water inlet temperature to the coolers is 95°F. During normal operation, the full-size service water outlet valves, which are used following a LOCA, are closed while the smaller (4" diameter) valves are open. Occasionally, during extended periods of high outside temperature, all four coolers are used to limit the average containment temperature to 120'F. Service water flow to the containment air coolers may be supplemented by using the 8" full size service water outlet valves.

Emergency Operation Upon receipt of a Safety Injection Actuation Signal, the fourth cooling unit is automatically started on the low speed setting and, simultaneously, the others are switched from their normally operating high speed setting to low speed operation. The full flow (8" diameter) service water outlet valves at each cooler are opened upon receipt of Safety Injection Actuation Signal. The service water inlet valves move to a throttled position upon receipt of a Safety Injection Actuation Signal, and return to the full open position upon receipt of a Recirculation Actuation Signal. With off-site power available under this mode of operation, three cooling units are switched to low speed and the fourth is started on low speed as described above. If off-site power is not available, the emergency diesel generators are started. Each of two emergency diesel generator busses carries the load of two cooling units. The evaluation of post-incident containment pressure/temperature response is provided in the Updated Final Safety Analysis Report (UFSAR). These evaluations consider the actual heat removal capacity of the containment air 1.

ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES coolers which is a function of service water flow and temperature, fouling, air flow, and containment pressure and temperature.

Plant Condition On Unit 2, No. 24 Containment Air Cooler fan motor became grounded and was declared inoperable at 0349 on Saturday, January 19, 2013. Technical Specification 3.6.6 Required Action C was entered with a Completion Time of 7 days to restore the Containment Air Cooling train to operable status. This Completion Time expires on Saturday, January 26, 2013 at 0349. Condition E would then be entered which requires the Unit be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and Mode 4 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

Investigation of the breaker trip revealed that a fault existed within the overall motor circuit. Further testing confirmed that the fault did not exist in the cable, penetration or motor junction. box. Testing did confirm the fault to be within the motor windings. The fault occurred shortly after restarting the motor.

This ground fault most likely initiated as an end turn fault, which typically occurs during motor starts.

This is a newly manufactured fan motor, not a rewound motor. The potential cause of the grounded fan motor is believed to be a premature winding failure of an unknown origin until further forensic testing can be performed.

The grounded fan motor must be replaced, it cannot be repaired. In order to affect the necessary replacement the containment polar crane must be used and the equipment hatch must be opened; these activities require the Unit to be placed in Mode 5. Therefore, it is not feasible to replace the motor while Unit 2 is operating. Additionally, Unit 2 is scheduled to shutdown for a refueling outage on February 17, 2013 (Mode 4 is scheduled for 1800 that day). Failure to address the inoperable Containment Air Cooler fan motor in a timely manner will result in an unscheduled shutdown of Unit 2.

Proposed License Condition Technical Specification 3.6.6, "Containment Spray and Cooling Systems", currently states:

"Two containment spray trains and two containment cooling trains shall be OPERABLE."

The associated Technical Specification Bases specifies in the Limiting Condition for Operation (LCO)

Section that, "two containment cooling trains (all four coolers) must be OPERABLE."

Calvert Cliffs is proposing a license condition be added to Appendix C of Renewed Operating License DPR-69 for Unit 2 to restrict the operating conditions under which the Unit 2 Containment Air Cooling Trains would be considered operable. The following License Condition is proposed:

"For the period from January 26, 2013 through February 17, 2013, for Technical Specification 3.6.6, an OPERABLE "A" train of the Containment Cooling system consists of two operable containment cooling fans and coolers and the associated instruments and controls. An OPERABLE "B" train of the Containment Cooling system consists of one operable containment cooling fan and cooler and the associated instruments and controls.

In addition, the following limitations must be met for each Containment Cooling train to be considered OPERABLE:

(1) The Unit 2 RWT water temperature shall not exceed 80'F, (2) The Unit 2 containment average air temperature shall not exceed 951F, (3) The Unit 2 initial containment pressure shall not exceed 1.0 psig, and (4) The Chesapeake Bay average water temperature shall not exceed 80'F."

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ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES To support this proposed change, analyses of the containment pressure and temperature following a LOCA and a MSLB was performed. The analyses are described below.

3.0 TECHNICAL EVALUATION

During a design basis accident (DBA), a minimum of one Containment Air Cooling train and one Containment Spray train is required to maintain the containment peak pressure and temperature below the design limits. The Containment Spray and Cooling Systems limit the containment temperature and pressure that could be experienced following a DBA. The limiting DBAs considered relative to containment temperature and pressure are a LOCA and a main steam line break (MSLB). The LOCA and MSLB are analyzed using computer codes designed to predict the resultant containment pressure and temperature transients. No DBAs, are assumed to occur simultaneously or consecutively. The postulated DBAs are analyzed with assuming the loss of one engineered safety features bus, which is the worst case single active failure, resulting in one train of the Containment Spray system and one train of the Containment Cooling system being rendered inoperable. The analysis and evaluation 'show that under the worst case scenario, the highest peak containment pressure and temperature are within the design for the containment structure. The analyses are described in the UFSAR Section 14.20 and assume a power level of 2754 MWt, one Containment Spray train and one Containment Cooling train operating, and initial (pre-accident) conditions for containment average temperature of 120'F and an initial RWT water temperature of 100°F. The analyses also assume a response time delayed initiation, in order to provide a conservative calculation of peak containment pressure and temperature responses.

In support of this license amendment request, the LOCA and MSLB DBA analyses described in UFSAR Section 14.20 were updated to include the following changes to the input assumptions.

• A Containment Air Cooling train was assumed to consist of one fan and cooler instead of two.

This is assumed for both trains even though one train still has both Containment Air Cooler fans operable.

. The containment initial temperature was assumed to be 95'F instead of 120'F. The current containment temperature is 911F. Based on the weather forecast for the next 23 days and the stable operating conditions with two Containment Air Cooler fans running, the containment temperature is anticipated to remain below 95°F for the duration of this request.

For the LOCA analysis only, the following assumptions also apply:

• The temperature of the water in the RWT was assumed to be 80'F instead of 100°F. The current RWT temperature is 69°F. The RWT is outside, exposed to the outdoor atmosphere and based on the weather forecast for the next 23 days, the RWT water temperature is not expected to approach the assumed limit of 80'F.

• The temperature of the ultimate heat sink (the Chesapeake Bay) was assumed to be 80'F instead of 90'F. The current temperature of the ultimate heat sink is 43°F. Based on the weather forecast for the next 23 days and the stable operation of the system providing water to the Containment Air Cooler cooling coils, the temperature of the inlet water is not expected to challenge the revised limit stated above.

. Mass and energy releases, for the LOCA analysis only, were updated to resolve a non-conservatism with the Westinghouse computer code time step data. This resolution results in a higher containment pressure in the initial stages of the analysis.

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ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES

• The initial containment pressure was assumed to be a maximum of 1.0 psig instead of 1.8 psig.

The containment pressure is currently 0.3 psig. The containment is normally vented when the pressure reaches 0.6 psig to ensure that the 1.0 psig limit is maintained.

These proposed limitations are reasonable based on the environmental and operating conditions for the limited time that this proposed amendment would be in effect. Historical data was reviewed where available and supports the reasonable nature of the assumptions. Note also that the analyses contain additional conservatism in that not all inputs were changed to be more realistic (ex. Service Water temperature was assumed to be 105 °F instead of the current 50 OF). This could provide some additional margin.

The analysis results are in Table 1. This table compares the results obtained from the current licensing basis as described in the UFSAR, Section 14.20 and the analyses performed in support of this proposed amendment. Enclosure 1 provides the analysis for the LOCA and MSLB DBA. Enclosure 2 provides an additional analysis for the LOCA DBA. These results show that the safety function provided by the Containment Cooling and Spray systems continue to be met, considering the worst case single failure and the existing loss of the No. 24 Containment Air Cooler.

Table 1, Analysis Results Current LOCA Proposed Current Proposed Containment results LOCA analysis MSLB results' MSLB Design analysis Basis Peak pressure 48.6 49.0 49.1 49.1 50 (psig)

Peak temperature 271.6 272.0 354.2 344.2 276 (OF)

Concrete surface temperature limit The pressure and temperature results of these analyses do not affect the offsite radiological consequences of a LOCA as previously analyzed in the UFSAR. The radiological results for a LOCA bound any releases from the MSLB (see the analysis contained in UFSAR Section 14.26, Maximum Hypothetical Accident). The LOCA offsite radiological dose consequence analysis is based on the maximum allowable containment leakage rate of 0.16% of containment air weight per day. Since the maximum allowable containment leakage rate is not being revised, containment leakage assumed in the LOCA analysis is not impacted. Therefore, the increase in the calculated peak containment internal pressure does not impact the offsite radiological consequences of the LOCA accident analysis.

The pressure and temperature results of these analyses do not affect the analysis of radiological consequences of a LOCA with respect to radiological dose to the Control Room operators. Calculated Control Room operator dose during a LOCA is dependent on the maximum allowable containment atmosphere leakage rate and is unaffected by calculated peak containment internal pressure, as discussed above. Since the maximum allowable containment leakage rate is not being revised, dose to the Control Room operators is not affected by a change in peak containment pressure.

The pressure and temperature results of these analyses do not adversely affect environmentally qualified equipment within Containment. A review of the effects of this analysis on the environmental qualification of equipment in Containment determined that the equipment remained qualified for service in the revised pressure and temperature environment.

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ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES PRA Evaluation Although we are not requesting a risk informed change to the, licensing basis, a risk assessment of continued operation with the degraded containment air cooler condition was performed. The No. 24 Containment Air Cooler failed on January 19, 2013. The Unit 2 refueling outage is scheduled to start on February 17, 2013. This is a period of 29 days. The risk assessment analysis used 30 days. This method of determining out-of-service time is consistent with incremental conditional core damage probability and incremental conditional large early release probability analysis noted in Regulatory Guide 1.177 for Technical Specification changes for entire period of exposure vice the change in exposure. This PRA analysis does not credit any improved success criteria for the decreased heat sink and air temperatures.

This analysis evaluates the condition where the No. 24 Containment Air Cooler is inoperable and the remaining Containment Air Cooling train components are Operable. To support the boundary conditions of this analysis, elective maintenance will not be performed on equipment that could significantly change the results of the PRA analysis. The incremental conditional core damage probability and incremental conditional large early release probability of 5E-07 and 3E-08, respectively are less than the thresholds of 1E-06 and IE-07 given in Regulatory Guide 1.177 for Technical Specification Completion Time changes.

4.0 REGULATORY SAFETY ANALYSIS 4.1 Applicable Regulatory Requirements/Criteria General Design Criteria 16 and 50 address the capability of the Containment to withstand the containment pressure resulting from a postulated design basis LOCA.

General Design Criterion 16, "Containment Design," states that reactor containment and associated, systems shall be provided to establish an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment and to assure that the containment design conditions important to safety are not exceeded for as long as postulated accident conditions require.

General Design Criterion 50, "Containment Design Basis," states that the reactor containment structure, including access openings, penetrations, and the containment heat removal system shall be designed so that the containment structure and its internal compartments can accommodate, without exceeding the design leakage rate and with sufficient margin, the calculated pressure and temperature conditions resulting from any LOCA. This margin shall reflect consideration of (1) the effects of potential energy sources which have not been included in the determination of the peak conditions, such as energy in steam generators and, as required by § 50.44, energy from metal-water and other chemical reactions that may result from degradation but not total failure of emergency core cooling functioning, (2) the limited experience and experimental data available for defining accident phenomena and containment responses, and (3) the conservatism of the calculational model and input parameters.

Although the Calvert Cliffs licensing basis is the draft General Design Criteria, these General Design Criteria continue to be met following the revised containment temperature and pressure analyses. The environmental qualification of equipment within Containment is not affected by these analyses. These analyses do not impact the maximum allowable containment leakage rate and therefore do not impact Control Room operator dose. The calculated peak containment pressure remains below containment design pressure.

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ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES 4.2 No Significant Hazards Consideration Calvert Cliffs Nuclear Power Plant is proposing an emergency amendment to Renewed Operating License DPR-69 for Calvert Cliffs Nuclear Power Plant (Calvert Cliffs), Unit 2 to add a License Condition to restrict operating parameters related to a degraded Containment Air Cooler train. These restrictions are proposed to address an inoperable containment cooling fan motor for a period from January 26, 2013 through February 17, 2013. The inoperable containment cooling fan motor cannot be repaired or replaced while Unit 2 is operating and the scheduled refueling outage begins for Unit 2 on February 17, 2013.

Calvert Cliffs has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, as discussed below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accidentpreviously evaluated?

Response: No.

The proposed addition of a License Condition to restrict operating parameters related to a degraded Containment Air Cooling train does not alter the assumed initiators to any analyzed event. The probability of an accident previously evaluated will not be increased by this proposed change. This proposed change will not affect radiological dose consequence analyses. The radiological dose consequence analyses assume a certain containment atmosphere leak rate based on the maximum allowable containment leakage rate, which is not affected by the change in calculated peak containment internal pressure. The 10 CFR Part 50, Appendix J containment leak rate testing program will continue to ensure that containment leakage remains within the leakage assumed in the offsite dose consequence analyses. The consequences of an accident previously evaluated will not be increased by this proposed change.

Therefore, operation of the facility in accordance with the proposed License Condition to restrict operating parameters related to a degraded Containment Air Cooling train will 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 accidentpreviously evaluated?

Response: No.

The proposed License Condition to restrict operating parameters related to a degraded Containment Air Cooling train has been analyzed to determine the impact of the restrictions on the post-accident containment temperature and pressure. The calculated peak containment pressure remains below the containment design pressure of 50 psig with these restrictions. This change does not involve any alteration in the plant configuration (no new or different type of equipment will be installed) or make changes in the methods governing normal plant operation. The change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

Therefore, operation of the facility in accordance with the proposed License Condition to restrict operating parameters related to a degraded Containment Air Cooling train would not create the possibility of a new or different kind of accident from any previously evaluated.

3. Does the proposedchange involve a significantreduction in a margin of safety?

Response: No.

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ATTACHMENT (1)

DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES The calculated peak containment pressure remains below the containment design pressure of 50 psig.

Since the radiological consequence analyses are based on the maximum allowable containment leakage rate, which is not being revised, the change in the calculated peak containment pressure does not represent a significant change in the margin of safety.

Therefore, operation of the facility in accordance with the proposed License Condition to restrict operating parameters related to a degraded Containment Air Cooling train does not involve a significant reduction in the margin of safety.

4.4 Conclusions

,Calvert Cliffs has determined that the proposed License Condition does not require any exemptions or relief from regulatory requirements and does not affect conformance with any regulatory requirements or criteria.

For this emergency license amendment request, Calvert Cliffs has determined the following criteria are met, (1) Failure to act in a timely manner will result in the shutdown of a nuclear power plant, (2) the proposed change does not involve a significant hazards consideration, (3) the application for the emergency license amendment request is timely and failure to make a timely application has not created the emergency, and (4) the emergency situation could not have been avoided.

Based on the considerations 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 continue to be conducted in accordance with the site licensing basis, and (3) the approval of the proposed change will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

The proposed amendment would change a requirement with respect to installed facility components located within the restricted area of the plant as defined in 10 CFR Part 20. 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(c)(9).

Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

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ENCLOSURE (1)

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CCNPP CONTAINMENT RESPONSE TO LOSS OF ONE CAC UNIT Calvert Cliffs Nuclear Power Plant, LLC January 22, 2013

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 FORM ^, CALCULATIN COVIEMKHU (CNO.CM-l 01-2001. ATTACHMENT I i A. INYMTUATOI Par, o 5ke IN CCNI'P E3 Nmi 0 KEGi cakuiWOh NW;~ CA07.%O5 Revbiam No": l Vsudw cak.Iuuif (Chuk am): ye Dawe kequm~ft Om", Pba Wagl PmI. Nwociee AM13,sM tAW

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CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 Table of Contents A CRON YM S & ABREV IA TION S .................................................................................................. 3

1. PURPOSE, BACKGROUND, AND INTRODUCTION ............................................................ 5 1.1 PU RP O SE .................................................................................................................................... 5 1.2. BA CK G RO UN D ......................................................................................................................... 6 1.3. IN TRO DU CTION ....................................................................................................................... 7 2 M ETHO D O F AN ALY SIS ....................................................................................................... 8 3 A SSUM PTION S .............................................................................................................................. 9 4 IN PUT DA TA ................................................................................................................................ 10

5. DOCUMENTATION OF COMPUTER CODES ...................................................................... 13

6. CA LCULA TION S ......................................................................................................................... 14

7. SU MM ARY & RESU LTS ........................................................................................................ 15

8. CON CLU SION .............................................................................................................................. 20

9. RECO MM EN D ATION S .................................................................................................................. 21

10. RE FEREN CES ............................................................................................................................... 22 A PPEN D IX A ........................................................................................................................................ 23 2

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 ACRONYMS & ABREVIATIONS (Not all these acronyms & abbreviations are used in the text of this calculation)

AOR" .......................... Analysis of record (to be superseded by this calculation)

EBD: .......................... End of Blowdown Phase of a LB-LOCA ESA: ............ Early Safety Injection Adjustment CAC: ............ Containment Air Cooler (Fan Cooler)

CCI: ............................ Double-ended slot break of cold leg on the pump discharge with 1 SI train CCNPP: .......... Calvert Cliffs Nuclear Power Plant CCW: ........... Component Cooling Water CCX: ............ Double-ended slot break of cold leg on the pump discharge with 2 SI trains CL: ............. Cold Leg CLPD: ........... Cold Leg Pump Discharge ABBCE/WEC: ........... Combustion Engineering/Westinghouse Electric Corp.

CEG: ............ Constellation Energy CEU: ............ Civil Engineering Unit CFR:."............ Code of Federal Regulations CONTRANS: ...... Containment Transients (ABBCE/WEC containment analysis code)

COPATTA: ................ Containment Pressure And Temperature Transient Analysis (Bechtel Code)

CSAS: ........... Containment Spray Actuation Signal CSP: ............ Containment Spray Pump DBA ............ Design Basis Accident DEGB: .......... Double-Ended Guillotine Break DESB: ........... Double-Ended Slot Break EBD: ............ End of Blowdown EDG: ............ Emergency Diesel Generator EEU: ............ Electrical Engineering Unit EQ: ............. Equipment Environmental Qualification ERF: ............ End of Reflood phase of a large break LOCA EPR: ............ End of Post Reflood phase of a large break LOCA ETL: ............ Early Terminate of LPSI FP: ............. Fine-Print Frequency GOTHIC: ........ Generation of Thermal Hydraulic Information for Containment (NAI/EPRI code)

GPM: ........... Gallons Per Minute H21: ............ 2 ft2 hot leg break with 1 SI train HHI: ........................... Double-ended slot break of hot leg with 1 SI train HHX: ............ Double-ended slot break of hot leg with 2 SI trains HL: ............. Hot Leg HPSI: .......................... High Pressure Safety Injection Pump HX: ............. Heat Exchanger LAR: .......................... License Amendment Request LPSI: ............ Low Pressure Safety Injection Pump LOCA: .......... Loss of Coolant Accident LB-LOCA: ....... Large Break LOCA (Double-Ended Break)

LOOP: .......... Loss of Offsite Power 3

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 min_SI: ....................... Minimum set of safety injection available (i.e., 1 EDG) maxSI: ...................... Maximum set of safety injection available (i.e., 2 EDGs)

M&E: ......................... Mass and Energy Transfer Rate (from CL, HL into containment)

MEU: .......................... Mechanical Engineering Unit MSLB: ........................ Main Steam Line Break NAU: .......................... Nuclear Analysis Unit NRM: ......................... Nuclear Regulatory Matters OSG: .......................... Original Steam Generators (replaced in early 2000)

RAS: ........................... Recirculation Actuation Signal RCP: ........................... Reactor Coolant Pump RSG: ........................... Replacement Steam Generators (current)

RWT: .......................... Refueling Water Tank SDC: ........................... Shutdown Cooling SGFP: ......................... Steam Generator Feed Pump SI: ............................... Safety Injection SIAS: .......................... Safety Injection Actuation Signal SGIS: .......................... Steam Generator Isolation Signal SRW: .......................... Service Water Train TDH: .......................... Total dynamic head of safety injection pump UFSAR: ...................... Updated Final Safety Analysis Report 4

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

1. PURPOSE, BACKGROUND, AND INTRODUCTION 1.1 PURPOSE The purpose of this calculation is to determine the effect of the loss of one CAC unit (SR 000083) on a DBA LOCA and MSLB. In specific, given a DBA LOCA or MSLB with only one CAC unit available, the goal is to:

a) Evaluate the containment integrity (UFSAR Chapter 14.20 peak pressure and vapor temperature profiles) b) Develop containment temperature/pressure profiles to be utilized by the EQ program per 10CFR50-49 c) Develop containment sump water temperature profile for the LOCA case.

5

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 1.2. BACKGROUND The Calvert Cliffs containment is equipped with two trains of spray and two trains of containment air coolers (CAC). Each train of CAC consists of two CAC units. Early Saturday morning (January 20, 2013), the Unit 2 containment air cooler (CAC 24) exhibited anomaly. Troubleshooting activities confirmed that its electric motor was grounded and cannot be replaced while online. Since the Unit 2 outage is scheduled for refueling shutdown around February 20, 2013 it is the intention of this calculation to primarily demonstrate that the containment pressure will not exceed the Tech. Spec. limit of 50 psig should a DBA LOCA or MSLB occurs during this period with the current plant configuration.

6

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 1.3. INTRODUCTION 1.3.1. LOCA INTRODUCTION The Calvert Cliffs DBA LOCA analysis credits only one train of CAC due to the assumption of the limiting single failure, which renders the second unit unavailable. This has been the prevailing assumption as used in multiple calculation packages throughout the years. This assumption is also used in the analysis , which was performed in support of the LAR as documented in Reference 1.

The present calculation package conservatively assumes that the faulty unit is located in the available CAC train. As a result, only one unit of CAC can be credited throughout the analysis.

1.3.2. MSLB INTRODUCTION The Calvert Cliffs DBA MSLB analysis credits two trains or four CACs. This is due to the assumption of the limiting single failure being the failure of the feedwater reg. valve to close. This has been the prevailing assumption as used in multiple calculation packages throughout the years. This assumption is also used in the analysis. Thus the present calculation package credits only 3 out of four CAC units. It must be added the duration of the analysis for the MSLB is about 10 minutes. In this case the RAS is not reached and therefore no post-RAS analysis is performed.

7

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 2 METHOD OF ANALYSIS The method of analysis used in this calculation is consistent with that used in Reference 1. The key differences are in the use of less conservative and more realistic values for key input data such as:

a) Initial vapor and heat conductor temperatures b) Refueling water tank (RWT) inventory temperature c) Component Cooling Water (CCW) inlet temperature (Only for the LOCA case)

More details about these input data are provided in Section 4. Since the GOTHIC models one CAC train instead of one CAC unit, to reduce the number of from two to one unit of CAC, the air flow rate through the CAC is reduced from 110,000 CFM to 55,000 CFM and the multiplier for the related forcing function was reduced from 1.0 to 0.5.

8

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 3 ASSUMPTIONS No assumptions are made in this analysis beyond those of Reference 1.

9

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 4 INPUT DATA The majority of input data are identical with those used in Reference 1. The CAC performance data are obtained from references as presented in APPENDIX A.

4.2. CHANGES TO INPUT DATA The following input data are changed from those used in Reference 1 as shown in Table 4.1.

TABLE 4.1. Changes in Input Data For LOCA of Reference I Input Data Value in Reference 1 Value in this calculation Vapor temperature 125 F 100 F Heat conductors 125 F 100 F RWT water temperature 100 F 80. F CCW inlet temperature 90 F 80. F Although the lower RWT temperature of 80 F also affects the spillage of the safety injection to the containment sump, the temperature of this stream is still retained at 100 F.

Due to the margin to the peak pressure and short duration of the MSLB analysis, only the initial vapor and heat conductors temperature were changed and nothing else. This also includes the initial containment pressure, which unlike the LOCA case is still retained at the conservatively high value of 1.8 psig.

TABLE 4.2. Changes in Input Data For MSLB of Reference 2 Input Data Value in Reference 1 Value in this calculation Vapor temperature 125 F 100 F Heat conductors 125 F 100 F It should be noted that the use of the same temperature for the heat conductors as that of the bulk vapor is conservative since generally the containment shell (the most important heat sink) is a few degrees lower that the bulk vapor temperature.

10

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 4.2.1. CHANGE IN INITIAL CONTAINMENT TEMPERATURE The selection of 100 F for initial vapor and heat conductor temperatures (the temperature is 95 F.

Considering 5 F for instrument uncertainty brings the initial temperature to 100 F) is based on the survey of a decade long data as shown in Figure 4.1. Temperature in the month of January and February is generally well below 90 F, making the selection of 95 F for initial temperature reasonable and realistic. This change is applied to both LOCA and MSLB cases.

Unit 2 Containment Temperawte History from 2P1T5309 1100 900 FIGURE 4.1. Historical Containment Temperature 11

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 4.2.2. CHANGE IN RWT TEMPERATURE The RWT is located outside the containment building, thus exposed to ambient temperature.

Heaters are provided to maintain a minimum temperature per Technical Specification. Therefore, selection of 80 F when daytime temperature is generally below 50 F is conservative. This change is applied only to the LOCA case.

4.2.3. CHANGE IN CCW TEMPERATURE The heat sink for the containment sump is a closed loop double heat exchanger. The primary heat exchanger is the shutdown cooling heat exchanger (SDC-HX) which in turn is cooled by the Component Cooling heat exchanger (CCW-HX). The Chesapeake Bay water flows into the tubes of the secondary side CCW-HX. A conservatively high temperature of 90 F has been used in the DBA LOCA model. This value is reduced to 80 F. This is still a conservatively high temperature as the bay water in this time of the season is generally on the order of 50 F. This change is applied only to the LOCA case 12

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

5. DOCUMENTATION OF COMPUTER CODES The results presented in this calculation are obtained from GOTHIC Rev. 8.0(QA), which is the latest QA'd version of the GOTHIC code. The verification & validation (V&V) of the installation of this code is documented in Reference 2.

All of the GOTHIC input files used in the analyses of this calculation will be stored in FCMS along with the text of the approved calculation in PDF. Additionally, the data files reside on the safety related PC, as shown in Tables 5.1 and on the H:\ drive as shown in Table 5.2.

TABLE 5.1. Location of files on the SR-PC (PCG6621)

File Location (SR-PC)

C:\CRA\CAC\CCIZ\CCI.GTH C:\CRA\CAC\MSLB\MSLB.GTH TABLE 5.2. Location of files on the Home Drive File Location (SR-PC)

H:\CRA\CAC\CCIZ\CCI.GTH H:\CRA\CAC\MSLB\MSLB.GTH 13

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

6. CALCULATIONS This includes calculations due to the changes were made for both LOCA and MSLB cases.

6.1. LOCA CALCULATIONS Recent analysis of CCNPP containment for various DBA LOCA indicated that the limiting LOCA is:

- A double-ended slot cold leg LOCA

- Break located on the discharge side of the RCP

- Concurrent loss of offsite power (LOOP)

- Concurrent loss of an emergency diesel generator (EDG)

This LOCA in Reference 1 is modeled in GOTHIC under CCI name. Therefore, the CCI case was chosen to make the changes outlined in Section 4 and to perform the analysis. No other changes have been made.

6.2. MSLB CALCULATIONS The limiting MSLB is a double ended guillotine break of the main steam line per Reference 2. The related GOTHIC model is entitled sl.

14

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

7.

SUMMARY

& RESULTS 7.1. PEAK PRESSURE & TEMPERATURE FOR LOCA The analysis show that the change in the input data as outline in Section 4 compensates the loss of one CAC during which the peak containment pressure remains below the Tech Spec. limit of 50 psig with a reasonable margin as shown in Figure 7.1. Figure 7.2 shows the containment vapor temperature.

49.7 49.6 493 -

49-4 49.2 49.1 42.9 190 195 200 205 210 215 220 225 T*ineI(W FIGURE 7.1. Comparison of peak pressures with Reference 1 274.5 273.5 -

S NewM Vapor Tentperaw~e VkorTn4eueILARMax 2723 .-.

2725. .. . .. .

2713 .. . . .. ..

2170 10 190 200 210 220 230 240 FIGURE 7.2. Comparison of peak temperature with Reference 1 15

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 7.2. 10CFR 50.49 ENVIRONMENTAL QUALIFICATION FOR LOCA Figure 7.3 compares containment pressure with that of Reference 1 and the ES-014 envelope.

Similarly, Figure 74 compares the key temperatures obtained in this calculation with those from Reference 1 and the ES-014 envelope.

60 5o 40 30 10

-4 - _4 -

01 10 100 1000 10000 100000 1000000 rhuse seci FIGURE 7.3. Containment pressure for two LOCA cases and ES-014 350 300 250 200 IL 100 50 0

0.1 10 100 1000 10000 100000 1000000 10000000 "bn1e K4 FIGURE 7.3. Containment temperature for two LOCA cases and ES-014 16

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 Note that the containment pressure in long term crosses into the ES-0 14 profile. This issue is reported to the EQ engineers who are working on an engineering response under ECP-13-000058. Subsequently, the issue has been deemed acceptable by EQ engineering, and is documented in the Fleet Configuration Management System associated with this ECP.

7.3. 10CFR 50.49 ENVIRONMENTAL QUALIFICATION FOR LOCA The sump water temperature in the revised LOCA is shown in Figure 7.4.

240 -

220 200 180 U

U E 160 is-140 120 100 0.1 10000 100000 1000000 10000000 7kne (see)

FIGURE 7.4. Sump water temperature in the revised LB-LOCA analysis 17

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 7.4. PEAK PRESSURE & TEMPERATURE FOR MSLB The analysis show that the change in the input data as outline in Section 4 compensates the loss of one CAC during which the peak containment pressure remains below the Tech Spec. limit of 50 psig with a reasonable margin as shown in Figure 7.1. Figure 7.2 shows the containment vapor temperature.

49.2 49 148.6 48.4 48-2 48 47.8 220 230 240 250 260 270 280 Time (sec)

FIGURE 7.5. Comparison of peak pressures with Reference 2 356 354 352

• 350 Ea 1348 346 344 342 4-61.5 62 62.5 63 63.5 64 64.5 65 65.5 66 66.5 67 Thi (sec)

FIGURE 7.6. Comparison of peak temperature with Reference 2 18

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 7.5. 10CFR 50.49 ENVIRONMENTAL QUALIFICATION FOR MSLB Figure 7.3 compares containment pressure with that of Reference 1 and the ES-014 envelope.

Similarly, Figure 74 compares the key temperatures obtained in this calculation with those from Reference 1 and the ES-014 envelope.

60 50 40 530 20 10 0

0o1 1 10 100 1000 10000 The (see)

FIGURE 7.7. Containment pressure for MSLB cases and ES-014 350 71T 300 250 9200

&150 E

100 so 0

0.1 10 100 1000 10000 Time (sec)

FIGURE 7.8. Containment temperature for MSLB cases and ES-014 19

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

8. CONCLUSION Using an initial vapor temperature and heat conductors of 100 F, the containment peak pressure in both cases of a DBA LOCA and MSLB remain below the containment design limit of 50 psig.

Regarding the MSLB, two issues need to be addressed:

A) Single Failure. The NSSS vendor (then ABBCE and now Westinghouse) performed extensive spectrum analysis to find the limiting single failure. In that effort, they had assumed two trains of CACs would be available and thus the failure of the feedwater reg.

valve to shut turned out to be the most limiting single failure. In this regard, concern may be raised whether the assumption of the availability of only three CACs would have resulted in the same limiting single failure. While this is a valid concern and can be resolved by performing a similar detailed single failure spectrum analysis, it can be argued that the same limiting single failure is applicable here for the reasons discussed under C)

B) The same cooler performance curve is used for both LOCA and for MSLB. Under accident conditions, cooler performance is affected by the steam content. For the MSLB, there is significant super heat conditions and the performance may be over estimated. If the vapor phase is used in the CACs, the saturation temperature and the containment peak pressure may indeed increase. While this concern may be alleviated by using the GOTHIC fan cooler model, the arguments under C) should alleviate this concern C) To alleviate the concerns raised under A) and B), the following mitigating factors should be considered:

a. While the LAR initial pressure allows 1. psig, an initial pressure of 1.8 psig is used in the MSLB analysis

b. While the initial vapor and thus the heat conductors are below 95 F, an initial temperature of 100 F (including 5 F instrument uncertainty) is used

c. While the CACs use much colder Service Water temperature, a temperature of 105 F is assumed in the analysis

d. While the RWT is a temperature on the order of 55 F (or less) a temperature of 100 F is assumed in the analysis 20

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

9. RECOMMENDATIONS There is no recommendation for this calculation. However, the goal of this analysis was to demonstrate that plant operation for a period of about one month with one CAC unit out of service is permissible with respect to containment response. The faulty unit will be fixed and brought back to service so that after the refueling outage the plant configuration will consist of two active trains of CAC (i.e., 4 operational CAC units).

21

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013

10. REFERENCES

1. CA07786, Rev. 0000, CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR, ECP-1 1-001022

2. CA06774, Rev. 0002, "Containment Response to DBA's For CCNPP Units 1&2", Sept. 08, 2008 22

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT CA07956 - Rev. 000 M. Massoud - J. Phillippi ECP-13-000058 January2013 APPENDIX A The CAC performance (i.e., rate of heat transfer) is performed in BECHTEL calculation M 36, Rev.2 and transferred to Nuclear Engineering (Analysis) unit in Memo ME940187.011.

23

CCNPP CONTAINMENT RESPONSE To Loss OF ONE CAC UNIT Masoud - J. Phillippi CA07956 ECP-13-000058 - Rev. 000 ... .,,- I t

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1 J24

ENCLOSURE ('2) z CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR Calvert Cliffs Nuclear Power Plant, LLC January 22, 2013

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Form 20, Calculation Coversheet (CNG-CM- 1.01-2001, ATTACHMENT 1) -

A. INITIATION Page I of---

Site 0 CCNPP Li NMP El REG Calculation No.: CA07786 Revision No.: 0000 Vendor Calculation (Check one): Li Yes 0 No Responsible Group: Fleet Nuclear Fuel, Nuclear Analysis Unit Responsible Engineer: Mahmoud Massoud B. CALCULATION Engineering Discipline: El Civil El Instr & Controls 0 Nuclear El Electrical El Mechanical [E Other

Title:

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LICENSE AMEN DM ENT REQUEST Unit 01 02 El COMMON Proprietary or Safeguards Calculation El YES 0 NO Comments:

Vendor Cale No.: NA Revision No.:

Vendor Name: NA Safety Class (Check one): 0 SR LI Augmented Quality LI NSR There are assumptions that require Verification during walkdown: Tracking ID: NA This calculation SUPERSEDES: NA C. REVIEW AND APPROVAL:

Responsible Engineer: Mahmoud Massoud t J'

• 4 08/14'/2012 Printed Name and Signature Date Is Design Verification Required? El Yes 0 No If yes. Design Verification Form is El Attached [0 Filed with:

Independent Reviewer: Dr. Thomas L. George eýý_ iqý ao Printed Name and gatufe Date Approval: John Massari Printed Name and Signature Date

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 CON.'>, INMtI.NT R r..PONS. AN At .Y.I S IN S IPPOAT orC CCN*. PP lJNiTS I & 2 LeýhR CA07786. Re. 000 M. Masso'id ECP 11-001022 AugnSI 2012 Form 201, Calculation (:overshre.t cCN3-':M. I'ii -2i'I. Alr-'ACI IM FwT I)

A. INITIATI(ON Pape of---

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Mc.ttion No-: CA0778- Rfkvisioi: No. 0000 Vcodcr Calculation rCl':cck oawj: 0 Yes E? No 7

R tponsibhi GOrup: 1l I= NXtueur [ital, Nucklr Anilysis k.nihl Respot ible tngirsExr: Mohmoud Massoud H. CALC(:UI..AIO)N E"nf'.,trin4 fi'selplinr, "-- Cit-. j Itswr & Control, S N'Ica.

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CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table of Contents Form 20, Calculation Coversheet ............................................................ Error! Bookm ark not defined.

ACRONYM S & ABREV IATION S ................................................................................................... 3

1. PURPOSE, BACKGROUND, AND INTRODUCTION ............................................................ 5 1.1 PU RPO SE .................................................................................................................................... 5 1.2. BACKGROUN D ......................................................................................................................... 6 1.3. INTRODUCTION ....................................................................................................................... 7 2 M ETHOD OF ANALYSIS ....................................................................................................... 9 3 A SSUM PTION S ............................................................................................................................ 16 4 IN PUT DATA ................................................................................................................................ 17

5. DOCUM ENTATION OF COM PUTER CODES ...................................................................... 21

6. CALCULATION S ......................................................................................................................... 22

7. SUM MARY ................................................................................................................................... 28

8. RESULTS ...................................................................................................................................... 39

9. CONCLU SION .............................................................................................................................. 42

10. RECOM M ENDATION S ................................................................................................................ 43 11 . RE FERENCES ............................................................................................................................... 44 A PPEN DIX A ........................................................................................................................................ 45 APPEND IX B ........................................................................................................................................ 49 APPEN DIX C ........................................................................................................................................ 55 APPEN DIX D ........................................................................................................................................ 60 APPEN DIX E ...................................................................................................................................... 112 APPEN DIX F ....................................................................................................................................... 121 APPEN D IX G ...................................................................................................................................... 125 2

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 ACRONYMS & ABREVIATIONS AOR: .......................... Analysis of record (to be superseded by this calculation)

EBD: ............. End of Blowdown Phase of a LB-LOCA ESA: ............ Early Safety Injection Adjustment CAC: .......................... Containment Air Cooler (Fan Cooler)

CCI: ............................ Double-ended slot break of cold leg on the pump discharge with 1 SI train CCNPP: ......... Calvert Cliffs Nuclear Power Plant CCW: ........... Component Cooling Water CCX: ............ Double-ended slot break of cold leg on the pump discharge with 2 SI trains CL: ............. Cold Leg CLPD: ........... Cold Leg Pump Discharge ABBCE/WEC: ..... Combustion Engineering/Westinghouse Electric Corp.

CEG: .......................... Constellation Energy CEU: ............ Civil Engineering Unit CFR: ............ Code of Federal Regulations CONTRANS: ............. Containment Transients (ABBCE/WEC containment analysis code)

COPATTA: ................ Containment Pressure And Temperature Transient Analysis (Bechtel Code)

CSAS: ........................ Containment Spray Actuation Signal CSP: ............ Containment Spray Pump DBA ........................... Design Basis Accident DEGB: .......... Double-Ended Guillotine Break DESB: ........... Double-Ended Slot Break EBD: ............ End of Blowdown EDG: ........... Emergency Diesel Generator EEU: ............ Electrical Engineering Unit EQ: ............. Equipment Environmental Qualification ERF: ............ End of Reflood phase of a large break LOCA EPR: ............ End of Post Reflood phase of a large break LOCA ETL: ............ Early Terminate of LPSI FP: ............. Fine-Print Frequency GOTHIC: ................... Generation of Thermal Hydraulic Information for Containment (NAI/EPRI code)

GPM: .......................... Gallons Per Minute H21: ............ 2 ft2 hot leg break with 1 SI train HHI: ............ Double-ended slot break of hot leg with 1 SI train HHX: ............ Double-ended slot break of hot leg with 2 SI trains HL: ............. Hot Leg HPSI: .......................... High Pressure Safety Injection Pump HX: ............. Heat Exchanger LAR: .......................... License Amendment Request LPSI: ........... Low Pressure Safety Injection Pump LOCA: .......... Loss of Coolant Accident LB-LOCA: ....... Large Break LOCA (Double-Ended Break)

LOOP: .......... Loss of Offsite Power minSI: ....................... Minimum set of safety injection available (i.e., 1 EDG) 3

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 maxSI: ...................... Maximum set of safety injection available (i.e., 2 EDGs)

M&E: ......................... Mass and Energy Transfer Rate (from CL, HL into containment)

MEU: ........... Mechanical Engineering Unit MSLB: ........................ Main Steam Line Break NAU: ........... Nuclear Analysis Unit NRM: ........... Nuclear Regulatory Matters OSG: ............ Original Steam Generators (replaced in early 2000)

RAS: ........................... Recirculation Actuation Signal RCP: ........................... Reactor Coolant Pump RSG: ........................... Replacement Steam Generators (current)

RWT: ......... Refueling Water Tank SDC: ..................... Shutdown Cooling SGFP: ........... Steam Generator Feed Pump SI: ............................... Safety Injection SIAS: .......................... Safety Injection Actuation Signal SGIS: .......................... Steam Generator Isolation Signal SRW : .......................... Service W ater Train TDH: ........... Total dynamic head of safety injection pump UFSAR: ......... Updated Final Safety Analysis Report 4

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

1. PURPOSE, BACKGROUND, AND INTRODUCTION 1.1 PURPOSE The purpose of this calculation is to determine the effect of the Westinghouse M&E correction (CR-2009-002919) on the UFSAR Chapter 14.20 peak pressure and temperature profiles as well as developing containment LOCA temperature/pressure profiles to be utilized by the EQ program per 10CFR50-49.

5

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1.2. BACKGROUND The current AOR (Reference. 2), uses M&E produced by ABBCE/WEC with coarse-print frequency (0.5 sec). This results in the peak mass flow rate through the break in the early stage of the blowdown phase of a LOCA to be obscured. In Spring 2009 ABBCE/WEC informed CCNPP of this defect (CR-2009-002919).

Also surveillance tests at CCNPP have shown that the HPSI pumps may deliver higher flow rates than credited in the AOR, which had assumed degraded dynamic head for HPSI pumps (Reference 9). WEC was then asked to produce a whole new set of M&E for cold leg and hot leg break LOCA DBA's using fine-print frequency and maximum safety injection (SI) flow rate for two cases of a) one safety injection train available and b) repeating the analyses for two safety injection trains available. (these are traditionally referred to as Max. & min. SI cases)

Since AOR had analyzed only a 2 ft2 hot leg break, WEC was additionally asked to produce double-ended slot break on hot leg, assuming 1 SI and 2 SI trains available using maximum SI flow rate.

The above data, as documented in Reference 7, were used to produce a revised containment response to LOCA DBA's (Reference 3) focusing on the long term cooling phase of the large break LOCA.

The purpose of that analysis was to develop the sump water temperature profile for NPSH and chemical precipitants per GSI- 191.

Reference 4 documents the recent analysis of the containment response to maneuvers involving HPSI, LPSI, and CSP given various DBA LOCA's for the purpose of upgrading the plant emergency procedure (EOP-05).

Calculation CA07725, Rev. 0000 (Reference 10) was originated to analyze the resolution of the containment ODO. Due to time constrain, the analysis of Reference 10 only addressed containment integrity. This calculation package is now originated to include both containment integrity as well as EQ. It should be added that the analysis of Reference 10 considers safety injection adjustment (termination of LPSI flow and throttling of HPSI flow) well before RAS. This is not the case in this calculation where similar to the AOR, the SI adjustment takes effect at RAS. This would support CCNPP's LAR, which should represent the current plant status2.

The short term M&E for various LOCA cases and the history of containment response analysis at CCNPP are shown in Appendices A and B, respectively.

OD refers to Operability Determination # 09-005, requiring Operations to follow administrative control on initial pressure to ensure peak pressure in a limiting LOCA DBA remains below the Tech. Spec. limit of 50 psig. The administrative control will be removed upon approval of our submitted License Amendment lowering the upper limit of initial pressure from 1.8 psig to 1 psig.

2 In a future analysis, SI adjustment will occur at 900 sec after LB-LOCA initiation.

6

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1.3. INTRODUCTION The Westinghouse M&E correction led to the imposition of Operability Determination/Functionality Assessment (OD/FA) on Operations. Due to the imposition of this OD/FA presently, the maximum containment pressure during normal operation must not exceed 1 psig. This is because, the maximum value of 1.8 psig as allowed in LCO 3.6.4 (Reference 1) results in the containment peak pressure to exceed the containment design limit of 50 psig. For this reason and based on the analysis documented in this calculation package, an LAR (i.e., Tech. Spec. change) will be required for submittal to the U.S. Nuclear Regulatory Commission. Upon approval, the initial containment pressure of 1.8 psig as used in the Analysis Of Record (AOR) for containment response to a LOCA DBA will be reduced to a maximum of 1 psig. Calculation CA07725, Rev. 0000 (Reference 10) dealt with the peak containment pressure and temperature.

The five LOCA types as analyzed in Reference 10 are also used in this calculation for EQ analysis.

Since the AOR (Reference 2) adjusts SI at RAS, in the analysis documented in this calculation package SI is also adjusted at RAS. This is because the goal is to ensure identical inputs and assumption between this calculation and the AOR except for:

- Revised M&E

- Revised initial pressure There are five additional differences between the models used in this calculation package and those of Reference 2:

- The volume representing reactor vessel is changed for closed monitoring of water level subsequent to SI adjustment. As discussed in Reference 10, the vessel inventory and initial conditions are retained so that these changes have no effect on the containment response

- The values used for Tagami heat transfer coefficient are revised to conform with the changes in the value of peak pressure and revised M&E

- Time to RAS is changed from 4174.78 seconds to 3029.81 seconds for LOCA type CCI. The latter is calculated by Westinghouse and is shorter than the former due to the more conservative values used for the SI flow rate

- The break sizes for long term cooling represent the actual pipe diameter or the assumed break area

- Two additional double-ended hot leg break LOCA cases are analyzed in this calculation, which did not exist at the time when Reference 2 was originated In Reference 10, the five DBA cases were identified with 4 letters, with the last letter representing higher versus lower SI flow rate per SI train. As shown in §6.0 higher SI leads to higher peak pressure in containment. Therefore, the last letter is superfluous, thus dropped and the five DBA LOCA cases in this calculation are referred to as:

CCI: Double ended split break on pump discharge with one SI train and high HPSI TDH CCX: Double ended split break on pump discharge with two SI trains and high HPSI TDH H21: 2 ft2 hot leg break with one SI train and high HPSI TDH HHI: Double ended split break on hot leg with one SI train and high HPSI TDH HHX: Double ended split break on hot leg with two SI trains and high HPSI TDH 7

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 No MSLB analysis is performed in this calculation rather, the results for peak P & T are carried from AOR (i.e., Reference 2) into Table 8.1 for the sake of completeness of the results.

8

\

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 2 METHOD OF ANALYSIS The laborious task of replacing various boundary conditions for the short blowdown phase, reflood phase, post-reflood phase, and various spillage flow rates for all the LOCA cases listed is already performed in Reference 10. Therefore, the method of analysis exactly follows the same method as detailed in Reference 10. However, while Reference 10 focuses on the short term cooling phase of the LOCA, the focus of this calculation package is on long term containment temperature and pressure profiles for UFSAR Chapter 14.20 and the EQ program. The method of analysis used in this calculation is the same as that used in Reference 3 and is echoed below.

"CCNPP'scontainment response analysis is based on the Bechtel's NRC approved methodology.

However, while Bechtel used the COPATTA computer code, CCNPP has been using various versions of the GOTHIC computer code. The containment analysis uses a one-node or single lumped volume to represent the containment. The flow rate through the break, through the spray header, andfrom the safety injection train are modeled as GOTHIC boundary conditions. While Westinghouse provides the mass and energy transfer rates during the blow down, refill, and reflood phases of a LOCA, the long term cooling phase M&E are calculatedfrom a simplified modelfor the RCS within GOTHIC. The complication with the RCS model is in the calculationof the energy transferfrom the SG secondary side inventory. In the long term such model will be devised and implemented For now, however, the sensible heatfrom RCS internals and SG tubes are obtainedfrom Westinghouse and included with the decay heat modeled using a GOTHIC heater in the vessel volume. Presently, the CACs duty is also modeled as a forcingfunction in conjunction with a GOTHIC cooler. In the long term, GOTHIC heat exchanger models will be used to replace the current model by including all the pertinent and participatingportions of the Service Water system.

Availability of containment safety systems depends on the assumed limiting single failure. The limiting single failure in turn is determined by trial runs during the production of M&E and primarily affects the number of available spray trains. The number of available CAC trains in a LOCA is always unity as a LOCA DBA must assume a concurrentLOOP. Thus in the case of 1 EDG, only one train of CAC would be available and in the case of 2 EDGs, one train of CAC is assumed unavailabledue to the loss of one train of Service Water (SR W).

Heat removalfrom the sump, following RAS, is accomplishedby modeling the component cooling system by a GOTHIC double heat exchanger. The sump cooling by the ECCS,peculiar to CCNPP design, requirescontainment spray train to be operational. This is because, the sprayflow passes through the tubes of the shutdown cooling heat exchanger, which in turn is cooled by the component cooling water (CCW) and eventually by the salt water with Chesapeake Bay being the ultimate heat sink The spray delayfor actuation is calculated separately and used in GOTHIC.

The calculationuses a simultaneous solution of the continuity and the momentum equation to find the time to fill the drainedspray riser and header. The calculated value is then augmented by the delay in spray pump reaching nominal speed and the instrument and signal delays. More details are provided in Section 4for explanation of Input Data.

9

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 The passive heat sinks in the containment are modeled as GOTHIC heat conductors. The coated conductors properly account for the primer and paint with vendor provided heat transfer properties. During RSG activities some neutron shields andplatforms were permanently removed from the containment. Improvised heat sinks consisting of sheets of steel, providing the same surface area and thickness, were placed in the containment to make up for the permanently removed materials.

Traditionally, the goal of containment analysis has been determination of peak pressure to ensure the integrity, of the containment structure. Subsequently, determination of the containment peak vapor temperature and EQ were also included in the evaluation of the final results.

Recently, due to Generic Letter 2004-012, "Containment Sump Issue ", sump water temperature is now also a criticalparameter. High sump water temperature lowers the NPSHAvailablefor ECCS pumps (upon taking suctionfrom the sump after RAS). It also increases the corrosionproducts leading to increased chemical precipitates in the sump. These precipitates have been found to significantly increase the sump strainerhead loss and do not precipitateout of solution until the sump has cooled to 140°F. EOP-5 requires termination of one of two containment sprays upon containmentpressure dropping to 2.8 psig. Termination of one containment spraypump reduces flow rate through the sump strainerprior to the onset of chemicalprecipitation,thus lowering head loss for the remaining operatingECCS pumps. Sump strainer analyses have shown that with certain insulation modifications, one HPSI and one CSP can operate even with chemical precipitateson the strainer. Therefore, analysisfor conservatively low sump water temperature must also be included in the overall containment response analysis to a LOCA. As mentioned in Section 1, no NPSH analysis is performed in this calculation nor the results obtained in this calculationare used in any NPSH analysis."

The GOTHIC schematics of all five LOCA cases analyzed in this calculation are shown in Figures 2.1 through 2.5.

10

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 2.1. GOTHIC schematic diagram of LOCA type CCI II

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 2.2. GOTHIC schematic diagram of LOCA type CCX 12

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 2.3. GOTHIC schematic diagram of LOCA type H21 13

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 2.4. GOTHIC schematic diagram of LOCA type HHI 14

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 2.5. GOTHIC schematic diagram of LOCA type HHX 15

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 3 ASSUMPTIONS No assumptions are made in this analysis beyond those of References 2, 3, and 10 as detailed in Appendix C.

16

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4 INPUT DATA The majority of input data are identical with those used in Reference 10 (analyzing containment integrity) including:

- Initial containment pressure of 1 psig (15.7 psia) instead of 1.8 psig (16.5 psia)

- Revised values for the Tagami heat transfer coefficient to conform with the changes in the value of peak pressure The remaining initial conditions for LOCA are similar to those used in References 2 and 3:

- Initial containment vapor temperature (F): ................ 125

- Initial relative humidity (%): ..................................... 20.0

- Initial heat conductor temperature (F): .................. 125' Details of input data as described in Reference 3 are echoed in Appendix D. All supporting materials and references for various input data, including those listed above are documented in Reference 13. Section 4.1 further clarifies the selection of containment initial relative humidity.

4.1. DETERMINATION OF CONTAINMENT INITIAL RELATIVE HUMIDITY The initial relative humidity of the containment vapor space used in all containment response analyses is 20%. This is a reasonably conservative value as lower relative humidity results in higher amount of non-condensable gases in the containment. This in turn increases peak pressure for two reasons, a) it increases the partial pressure of air and b) it degrades condensation on colder surfaces of containment heat sinks. Reference 16 (included in this calculation package as Appendix G) provides a detailed description on the selection of 20% initial relative humidity.

Briefly, the historical data were obtained from the control room log book for both Units 1 and 2.

Focusing on the data of Unitl in Table I of Reference 16, we note the highest relative humidity of 36% (2 days at this value) and the lowest relative humidity of 19% (1 day at this value). The longest duration of 24 days, containment had a relative humidity of 33%.

Calculating a linear averaging, we find a value of 31% while the statistical means gives a 30%

value with confidence limit of 95%. If for the sake of argument, we assume a dry atmosphere with a relative humidity of 0%, GOTHIC for LOCA type CCI predicts a peak pressure of 49.776 psig.

Comparing this value with the peak pressure of 49.617 psig at 20% relative humidity demonstrates that a 20% drop in relative humidity would result in an increase in the peak pressure of less than 0.2 psi or about 0.3%

In conclusion, the selection of 20% relative humidity for all containment response analysis has been appropriate and reasonably conservative.

3 Except for energized electrical penetrations, which are assumed to be at a higher temperature 17

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.2. CHANGES TO INPUT DATA Although the majority of data used in this calculation package are identical to those used in Reference 10, there a few exceptions as noted below:

a) The minimum time step size for the first five seconds were reduce to resolve a slight bump in the graphs for containment vapor temperature b) Up to this calculation package, all previous GOTHIC models used a break flow area of 100 ft. In this calculation package, the actual value for the break size for double-ended break on hot leg and cold leg and the 2 ft2 break on the hot leg is used. Therefore, the cold leg LOCA cases use a break flow area of 9.82 ft2 and hot leg LOCA cases use a break flow area of 19.24 ft2 , except for H21 case. Corresponding hydraulic diameter for the flow path based on a circular flow area was calculated and specified in the related GOTHIC models.

c) To resolve an initial dip in the graphs of containment pressure and vapor temperature, a small water volume, with a fraction of 1.E-5 of total volume, was considered for the sump.

While this amount of water results in smooth trend for pressure and vapor temperature it has no effect on the GOTHIC calculations and results.

d) The safety injection adjustment was modeled to take place at RAS. This is to conform with the current plant procedure requiring operators to take action at RAS. In a future analysis this will be changed to resolve the concern of air binding in SI pumps due to vortex generation in RWT. More details regarding this item is provided in Section 4.2.

4.3. TIMING FOR ADJUSTMENT OF SAFETY INJECTION FLOW RATE Given a LOCA DBA, the plant protection system issues a SIAS upon receiving signal from several set points, resulting in water delivery to the RCS from the RWT by the ECCS pumps (HPSI &

LPSI). Withdrawing water from RWT depletes its inventory. The Recirculation Actuation Signal (RAS) occurs when a minimum inventory in RWT is reached. At RAS the ECCS pump suction is aligned to containment sump. For double-ended LOCAs, the time to RAS is a function of the assumed single failure. Thus, LOCA cases with two trains of SI pump (also referred to as maxSI cases) have a shorter time to RAS while LOCA cases with one train of SI pump (also referred to as min_SI cases) have a longer time to RAS. In previous containment response analyses, a time to RAS of 32 minutes had been calculated by Design Engineering and provided for use in containment response analysis. Design Engineering has revised this value to 1800 sec (Reference 15). Since for min _SI cases the SI flow rate is smaller to avoid vortex concerns no reduction in the calculated time to RAS is introduced. For these cases the values calculated in Reference 14 have been used.

Per plant procedure (EOP-05), for all LOCAs, the LPSI pumps are automatically turned off and the HPSI pumps are throttled (this action is referred to as SI adjustment in this calculation package) at RAS. Since Reference 15 specifies 1800 seconds as time to RAS for all maxSI cases, in this calculation package SI adjustment is also modeled to occur at 1800 seconds.

18

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Also note that whether min _SI or maxSI, the SI flow rates could be based on the maximum or minimum pump performance TDH of the HPSI pumps. Prior to recent upgrade of the containment response analysis calcs. (as detailed below), the minimum pump performance TDH values had been used to predict the SI flow rate.

In 2009, Westinghouse Electric notified CCNPP of an error in editing their M&E data. To resolve this error all containment response analyses cales. are being revised. This revision also includes three activities:

a) The ECCS flow rates were upgraded using maximum TDH for the HPSI pumps (Reference

14) since analysis showed that more SI was more conservative, b) Double ended slot break hot LOCAs (for one and two trains of SI) were also analyzed in addition to the 2 ft2 hot leg break (Reference 14) c) To further eliminate the possibility of vortex in RWT and to reduce the flow rate through the passive sump strainer, SI adjustment at 1200 sec and 900 sec were also investigated (Reference 4) but are still not implemented.

As described in item c), while the 900 sec and 1200 sec for SI adjustment were analyzed (Reference 3), these values have not been implemented in the plant procedure (EOP-05). Thus this calculation package supports the current 1800 seconds for the time to RAS for LOCAs with maxSI. values calculated in Reference 14. In an upcoming analysis, to supersede this calculation package, SI adjustment will take place at 900 sec. This discussion is summarized in Figure 4.0.

J 0

LL.

ui EBD ESA RAS Time Figure 4.0 Key Milestones in Containment Response Analysis for LB-LOCA (Reference 3)

EBD: End of Blowdown ESA: Early SI Adjustment 19

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 RAS: Recirculation Actuation Signal It is also noteworthy that prior to the new M&E a cold leg LOCA with two trains of SI (in this calc, referred to as CCX) was the limiting LOCA with respect to containment integrity. However, with the revised M&E of Reference 14 a cold leg LOCA with one train of SI (in this calc. referred to as CCI) becoming the limiting LOCA case with respect to con peak pressure in containment.

20

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

5. DOCUMENTATION OF COMPUTER CODES The results presented in this calculation are obtained from GOTHIC Rev. 8.0(QA), which is the latest QA'd version of the GOTHIC code. The verification & validation (V&V) of the installation of this code is documented in Reference 11.

All of the GOTHIC input files used in the analyses of this calculation are stored in FCMS along with the text of the approved calculation in PDF. Additionally, the data files reside on the safety related PC, as shown in Tables 5.1 and on the H:\ drive as shown in Table 5.2.

TABLE 5.1. Location of files on the SR-PC (PCG6621)

File Location (SR-PC)

C:\CRA\OD\LAR\CCIZ\CCI.GTH C:\CRA\OD\LAR\CCXZ\CCX.GTH C:\CRA\OD\LAR\H2IZ\H2I.GTH C:\CRA\OD\LAR\HHIZ\HHI.GTH C :\CRA\OD\LAR\HHXZ\HHX.GTH TABLE 5.2. Location of files on the Home Drive File Location (SR-PC)

H:\CRA\OD\LAR\CCIZ\CCI.GTH H:\CRA\OD\LAR\CCXZ\CCX.GTH H:\CRA\OD\LAR\H2IZ\H21.GTH H:\CRA\OD\LAR\HHIZ\HHI.GTH H:\CRA\OD\LAR\HHXZ\HHX.GTH The final results for containment peak pressure obtained from the QA'd GOTHIC 8.0 are presented in Table 8.1.

21

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

6. CALCULATIONS Table 6.1 echoes the results obtained from GOTHIC analysis, currently constituting the AOR. As mentioned in §2.0, the updating of various boundary conditions for the blowdown phase, reflood -

post-reflood phase, and various spillage flow rates for all the LOCA cases listed in Table 1.2 were already performed in Reference 3. Replacing the coarse M&E values with the fine print (while retaining all other aspects of the GOTHIC models such as Components and Thermal Conductors of Ref. 2) results in higher peaks for both containment pressure and containment vapor temperature as shown in Table 6.2. Table 6.3 presents the same results but for the maximum safety injection flow rate per SI train (due to the higher SI pump TDH).

TABLE 6.1. The AOR Peak Values for LOCA Using original M&E (Reference 2)

LOCA Typet Peak Pressure Peak Vapor Temperature (psig) (F)

CCIK 48.45 271.4 CCXK 48.60 271.6 H2IK 48.39 271.5 t See below for description of LOCA type acronyms TABLE 6.2. Peak Values for LOCA Using Fine Print Blowdown & Degraded HPSI TDH (Reference 10)

LOCA Typet Peak Pressure Peak Vapor Temperature (psig) (F)

CCIK 50.15 273.7 CCXK 50.38 273.9 H2IK 49.70 273.2 t See below for description of LOCA type acronyms TABLE 6.3. Peak Values for LOCA Using Fine Print Blowdown M&E & Maximum HPSI TDH (Reference 10)

LOCA Type Peak Pressure Peak Vapor Temperature (psig) (F)

CCIZ 50.65 274.5 CCXZ 50.50 274.2 H2IZ 50.50t 273.5 HHIZ 51.30 275.5 HHXZ 50.97 275.0 t Unlike AOR, which had used 100 ft, a break area of 2 ft2 is used here, which increases peak pressure 22

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Description of Acronyms used for LOCA types in Tables 6.1 trough 6.3 CC: Double-ended slot break on cold leg pump discharge, HH: Double ended slot break on hot leg H2: 2 ft2 break on hot leg I: 1 train of SI X: 2 trains of SI K: Degraded HPSI pump TDH Z: Maximum HPS pump TDH As demonstrated in Table 6.3, higher SI leads to higher peak pressure. Thus the fourth letter in the LOCA type is dropped and these cases are simply referred to as CCI, CCX, H21, HHI, and HHX.

In §6.1 it is demonstrated that application of correct values for the Tagami heat transfer coefficient would result in lower peak pressure for the double-ended hot leg breaks than those shown in Tables 6.2 and 6.3.

The comparison of values in these tables indicates that the degraded SI pump TDH (minimum SI flow rate per SI train) results in lower values for the peak pressure and vapor temperature than those corresponding to the higher TDH (maximum SI flow rate per SI train). In Reference 3, it was also concluded that the high HPSI pump TDH results in higher sump water temperature.

Therefore, in this calculation only the LOCA cases, which are based on the high SI pump TDH are evaluated.

23

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 6.1. TAGAMI HEAT TRANSFER COEFFICIENT The containment peak pressure and vapor temperature listed in Tables 6.2 and 6.3 are obtained based on the Tagami heat transfer correlation of Reference 2. However, the coefficients of this correlation depend primarily on the total energy deposited up to the time of the first peak pressure (References 5 and 6). Since both time to the first peak pressure and the total energy deposited in that period have changed due to the revised M&E, new peak values should be calculated using the revised vales for the heat transfer coefficient predicted by the Tagami correlation.

According to the Tagami correlation, the heat transfer coefficient during the blowdown phase of a LOCA varies linearly with time to a maximum value:

The maximum value of the heat transfer coefficient is given as:

S=Ctu 0.62 Where in this relation C: A constant whose value in SI system of units is 0.607 and in British Units is 72.5 tfp: Is the time of the first pressure peak in seconds U: Energy (Btu) released from the RCS to the containment through the break during tfp V: Total containment volume (ft 3) if modeled as GOTHIC lumped volume h,,a: Heat transfer coefficient (Btuihr-ft2 -F)

Substituting for h,,x, the Tagami heat transfer coefficient becomes:

hBowdown - t Where hBI0odo, 0 has also units of Btu/hr-ft2 -F. Tables 1, 2, 3, and 4 of GOTHIC heat conductors heat transfer coefficients (corresponding to a double-ended hot leg LOCA) are shown below.

Table 4 contains the data for the Tagami heat transfer coefficient.

Values obtained in Tables 6.2. and 6.3 are based on the heat transfer coefficient Type 5,which was pertinent to a 2 ft2 hot leg break. When using the correct value for tfp and U, a much lower peak pressure is calculated as discussed in §8.0.

24

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Tye rn3l/erN He t.cid" I

l/H I

,--V I .,.p 11a ni]!°nd U

Crý F

I ~ a, imp.

0.T-r b-Tr I

Heat Transter Cot:ýtti,-ient Tý,.-,pes T-al--ýle Char. Mat Wnv For Pon% mom I Knimum Char.

I Type Length Poet Exp Rnef YxID Vel A Conv HTC Height

1. (ft) FF FF FF IFF HUI) F (B/h-ft2-F) (ft)

I DEFAULT DEFAULT 2 DEFAULT DEFAULT DEFAULT DEFAULT DEFAULT DEFAULT DEFAULT DEFAULT I

lI Total pewl Imitial BD Pos"BD Pust-BD Type Con3t Heat We Exp Value Exp Exp Direct

1. iý'T 1:E:t u:1 Is e c B/h - f 2 - F yt xt FF 1 7h 5 3WeNOH. 56. .62 0. 1 1. 0.025 0 4

5 7L 5 W65408. 5K 0.62 0. L 0.025 0 25

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 6.2. BLOWDOWN ENERGY RELEASE TO CONTAINMENT To calculate the values of U for various LOCA cases, the data provided by Westinghouse (Ref. 7) were integrated (as shown in Table 6.4) and specified in Table 4 of GOTHIC's HTC.

TABLE 6.4. Tagami Correlation Parameters U and tfp for Various LOCA Types LOCA Time to First Peak Energy Released (sec) (Btu)

CCI 13 2.862E8 CCX 13 2.862E8 H21 56 3.097E8 HHI 10 2.926E8 HHX 10 2.926E8 The above values are obtained by using trapezoidal integration. A sample for LOCA type H21 is included in APPENDIX F.

26

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 6.3. 10CFR50.49 ENVIRONMENTAL QUALIFICATION Regarding 10CFR50.49 environmental qualification, several parameters must be traced and their trend compared with the manufacturers envelope or other established limits. These include containment total pressure, relative humidity in containment, and containment vapor temperature.

Since in a large break LOCA, the relative humidity quickly raises to 100% or may even become slightly supersaturated (i.e., 0 > 100%), the focus in this calculation is on the containment total pressure and vapor temperature. Regarding temperature, both containment vapor temperature as well as the saturation temperature at total containment pressure (i.e., steam partial pressure plus the non-condensable gas partial pressure) are traced and the graph of their trend are compared with the ES-014 envelope.

27

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

7.

SUMMARY

7.1. PEAK PRESSURE & TEMPERATURE A containment response analysis to five types of LOCA DBA are performed in this calculation package. The blowdown M&E for all LOCA cases use a fine print frequency of 0.05 sec. These LOCA cases consider double-ended slot (split) break of cold leg (pump discharge side) and hot leg. The latter considers an additional case of 2 ft2 break. Both double-ended slot breaks consider the availability of one and two safety injection trains, assuming each train injects at the maximum flow rate.

The GOTHIC containment analysis models developed in Reference 2 and retained, with respect to M&E in Reference 3, were updated with respect to the coefficients for the Tagami correlation for heat transfer coefficient in the blowdown phase of the LOCA cases. The results using the above changes and assuming initial containment pressures of 1.8 and 1.0 psig are as shown in §8.0.

28

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 7.2. 10CFR 50.49 ENVIRONMENTAL QUALIFICATION Figure 7.1 compares the vapor temperature of all five LOCA types. Figure 7.1-1 is an extension of Figure 7.1 where less limiting cases are removed and scales on the abscissa and ordinate are modified to accentuate the differences between the remaining cases.

280

-- H21' 260 ~12 1 I 0r220 CCi 200 _ --

E I-O 0

10.

0.0 0.0 0.1i 1 0 10 100100100010001000 1L40 -- 7'- _CI_---__ --- _

100 0.01 0.1 1000 1001000 Time (see)

Figure 7.1. Comparison of vapor temperature for all LOCA cases 29

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 240 220 200 C

U 4W 180 za-CL 0.

160 0

140 120 100 1-10000 100000 1000000 Time (sac)

Figure 7.1-1. Comparison of vapor temperature profiles)

Comparison of containment pressure profiles for all five LOCA types is shown in Figure 7.2.

indicating that the double-ended slot break with one SI train available (CCI) is the most limiting LOCA case not only for containment integrity but also for long term temperature and pressure used in EQ analysis.

30

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 65 ___

60 55 50 ------

~45 Lw40 a, 35 i 30

~25 20 15 1E-02 1.E-01 1-E+00 1.E+01 1.E+02 11E+03 11E+04 11E+05 11E+06 Time (sec)

Figure 7.2. Comparison of containment pressure profiles 31

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Similar trend exists between the graphs of saturation temperature at containment total pressure as shown in Figure 7.3. This figure shows that CCI is a more limiting cold leg LOCA case except for a short period of time at RAS, which CCX has a higher vapor temperature. This is due to the fact that the CCI time to RAS occurs 2 minutes after CCX time to RAS.

300 -7 290 .CO(

ii" 280 - -CC 270 260 **

• 250 240 o 230----

4-b M 210 -

200 -

0.001 0.1 10 1000 100000 10000000 Time (sec)

Figure 7.3. Comparison of saturation temperature profiles of cold leg LOCA 32

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 The saturation as well as the vapor temperature of the cold leg LOCA cases are compared with the ES-014 envelope as shown in Figure 7.4. The hot leg LOCA cases are excluded as they are less limiting. Also excluded from this figure is the MSLB data. This is because the AOR has already addressed the MSLB comparison and the changes in M&E affect only the LOCA DBAs.

300 280 -

260 -

240 -

9 22 0 -

E 160 -

IO0 140 -

1200-100 -

0.1 1 10 100 1000 10000 100000 1000000 10000000 tune (sec)

Figure 7.4. Comparison of CL-LOCA vapor & saturation temperature profiles 33

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 In addition to the comparison of the vapor temperature with ES-014 data, three types of electrical penetrations through the containment shell were analyzed for both energized and non-energized cases:

- Stainless steel Amphenol

- Epoxy Amphenol

- Polyolefin Raychem The electrical penetrations are not modeled in this calculation rather performed in CA04340, Rev.

0000 (Reference 12). These penetrations are now exposed to the vapor temperature for various LOCA cases of this calculation. Their responses to the revised vapor temperature are' shown in the graphs below. The graphs shown here are for the limiting LOCA case CCI. In these graphs the energized electrical penetrations are shown in red. Physical properties of the electrical penetrations are shown in Table 4.5.7 of Appendix D.

34

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 7.5. Temperature Response of Stainless Steel Amphenol Electrical Penetrations Figure 7.6. Temperature Response of Epoxy Electrical Penetrations 35

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 7.7. Temperature Response of Raychem A Penetrations Figure 7.8. Temperature Response of Raychem B Penetrations 36

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Figure 7.9. Temperature Response of Raychem C Penetrations 65 60 55 1* 50 Z 45

~40 C 35 E

S30 30 U 25 20 15102 1.-2 11-01 I.E-iOU 11E+01 11E+02 11E+03 11+04 11E+05 11E+06 Time (sec)

Figure 7.10. Comparison of containment pressure for various CL -LOCA types with ES-014 Data 37

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Finally, the containment pressure profiles for both cold leg and hot leg break LOCA are compared with the ES-014 data as shown in Figure 7-10.

The graphs shown in Figures 7.4 and 7.10 are utilized by EQ to re-assess EQ external to this calculation. The graphs shown in Figures 7.5 through 7.9 can also be utilized by EQ to re-assess certain equipment (i.e., Amphenol Electrical Penetrations) external to this calculation. The use of these graphs are subject to the clarifications of Section 7.2-1.

7.2-1 ELECTRICAL PENETRATIONS CAVEAT The graphs of Figures 7.5 through 7.9 are based on the architect engineer's (Bechtel) approved methodology. However, the modeling of the energized penetration does not fully conform to regulatory guidelines and may be non conservative. In particular:

a) The internal heating is uniformly distributed over the electrical conductor and the insulation. This will minimize the internal temperatures in the conductor.

b) The conductors are initialized at uniform temperature. With the internal heating, the initial internal temperature will be hotter than the assumed surface temperature. In a future revision, an initialization time domain, with a large conduction to hydraulic time step ratio, could be used to properly initialize the temperature profiles.

c) The characteristic length of the electrical penetrations are not set equal to the diameter of each components. As such, GOTHIC uses the containment hydraulic diameter.

d) The forced convection heat transfer applied to the electrical penetrations may not fully conform with the NUREG-0588 requirement since the velocity used may not be the same as the velocity calculated from V = 2 5 rhlBD/Vcontainment specified in NUREG-0588. In this relation, Vis in ft/sec, blowdown mass flow rate in lbm/hr, and containment volume in ft3.

38

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

8. RESULTS 8.1. PEAK PRESSURE & TEMPERATURE Results for the initial containment pressure of 1.8 psig are shown in Table 8.1. Shown in this table are also the values pertinent to a MSLB, which are obtained from Reference 2 and presented here for information only. Tables 8.2 shows the peak values assuming an initial containment pressure of 1 psig, respectively.

TABLE 8.1. Peak Values Using Fine Print Blowdown M&E, Maximum TDH, and Pi = 1.8 psig LOCA Time to Peak, PIT Peak Pressure Peak Vapor Temperature (see) (psig) (F)

CCI 204 50.65 274.5 CCX 173 50.50 274.2 H21 72.0 50.20 273.2 HHI 10.0 47.45 270.7 HHX 10.0 47.45 270.7 MSLBt 250/65 49.10 354.0 t From Reference 2 TABLE 8.2. Peak Values Using Fine Print Blowdown M&E, Maximum TDH, and Pi = 1.0 psig LOCA Time to Peak, PIT Peak Pressure Peak Vapor Temperature (sec) (psig) (F)

CCI 204 49.62 274.4 CCX 173 49.46 274.2 H21 72.0 49.40 274.2 HHI 10.0 46.50 270.3 HHX 10.0 46.50 270.3 Tables 8.1 and 8.2 show that the peak vapor temperature is a weak function of slight changes in initial containment pressure. These tables also show that the LOCA case of CCI is the limiting case with respect to containment peak pressure. The trend of containment peak pressure as a function of containment initial pressure for this case is presented in Figure 8.1. This figure shows a nearly linear variation in the range of initial pressures used in the analysis.

39

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 For a given initial temperature and relative humidity, a higher value for initial pressure results in calculating a higher mass for the non-condensable gas (air). This in turn increases the gas partial pressure. Since the containment total pressure is the summation of the condensable and non-condensable gases, a higher initial pressure not only contributes to the peak pressure by its absolute value but also increases the peak pressure by degrading the condensation mechanism, thus resulting in higher vapor remaining in the containment atmosphere.

All the LOCA cases analyzed in this calculation package use an initial relative humidity of 20%.

If instead using a relative humidity of 50%, as generally used in containment response analysis, the value of the peak pressure corresponding to the limiting case drops by 0.2 psi. The initial value for the containment vapor temperature of 125 F includes a 5 F instrument uncertainty. Using a lower initial containment vapor temperature of 120 F slightly increases peak pressure for similar reasons discussed above for higher initial pressure.

50.8 50.6 -

w 50.4 50.2 so ,

50 49.8 49.6

"*49.2 o 49 U

48.8 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 Containment Initial Pressure (psig)

FIGURE 8.1. Variation of containment peak pressure with initial pressure given initial relative humidity of 20% and containment vapor emperature of 125 F (Reference 10)

In all the LOCA cases it is conservatively assumed that the friction length is zero. If a value equal to the inertia length is used, it would result in the peak pressure to drop by several psi.

40

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 8.2. 10CFR50.49 ENVIRONMENTAL QUALIFICATION The changes in the LOCA M&E as depicted in Section 7.2 are utilized by EQ to re-assess EQ equipment external to this calculation..

41

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

9. CONCLUSION Using an initial vapor temperature of 125 F and an initial relative humidity of 20%, a reduction in the containment initial pressure of even 0.6 psi (from 1.8 psig to about 1.2 psig) would result in the containment peak pressure in the limiting LOCA DBA (CCI) to drop below the containment design limit of 50 psig. Furthermore, the revised LOCA M&E will be used in another calculation to re-assess the EQ equipment.

42

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

10. RECOMMENDATIONS None.

43

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

11. REFERENCES

1. Calvert Cliffs Power Plant, Units 1 and 2, Technical Specification October 19, 2011

2. CA06774, Rev. 0002, "Containment Response to LOCA and MSLB for Calvert Cliffs Units 1 and 2", September 08, 2008

3. CA07458, Rev. 0000, "Analysis of Containment Sump to Hot & Cold Leg LOCA DBAs For Calvert Cliffs Units 1 and 2", September 15, 2010

4. CA07634, Rev. 0000, "Containment Response Analysis To DBA LOCA for Procedure Upgrade," December 2011

5. Slaughterbeck, D. C., "Review of Heat Transfer Coefficients for Condensing Steam in a Containment Building Following a Loss Of Coolant Accident", IN-1388, September 1970.

(This is Reference 13 of Reference 6 below)

6. Lin, C. C. et al., "CONTEMPT4/MOD6: A Multicompartment Containment System Analysis Program," NUREG/CR-4547, March 1986

7. CA07460, "Containment LOCA Blowdown Mass & Energy Release Data with Increased SI Pump Flow for Calvert Cliffs Units 1 & 2", August 31, 2010

8. CA06775, Rev. 0000, "Verification & Validation of GOTHIC 7.2A On PCG662 1," Feb. 2007

9. DE07512, "Operability Evaluation on Minimum Time to RAS", Jan. 11, 2008

10. CA07725, Rev. 0000, "Analysis of Containment Integrity in DBA LOCA for CCNPP Units 1 and 2:, January 19, 2012

11. CA07785, Rev. 0000, "Verification & Validation of GOTHIC 8.0(QA)", June 2012

12. CA04340, Rev. 0000, "GOTHIC Analysis of Containment Penetrations Temperature Profile"

13. CA05892, Rev. 0000, "Containment Response to OSG and RSG DBA for USAR, May 2002

14. Westinghouse Electric Company letter and attachments, LTR-OA-10-84, Rev. 0, "Transmittal of Verified Mass & Energy Release and Long Term Heat Rate Data for Calvert Cliffs LOCA Containment Analysis," August 06, 2010.

15. CA04903, Rev. 0002, "Compute The Minimum Time to RAS", 10/29/2007.

16. BGE Memo, NEU 94-162, From M. Massoud To W. J. Lippold. "Determination Of Initial Containment Relative Humidity For Safety Related Containment Response Analysis,", May

26. 1994 44

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX A BLOWDOWN M&E FOR VARIOUS LOCA CASES 45

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 TABLE A.1. M&E of Double-Ended Hot Leg Slot Break (Ref. 7)

TIME 1 MAS RATZ 1 NTHALPY (sec) i (Jlbu/hr) I (STU/lbui) 0.000 0.OOOOOE+00 607.81 0.050 4.79112E+08 607.81 0.100 4.72910E+08 607.73 0.150 4.88314E+08 609.73 0.200 4.66782E+08 610.51 0.250 4.45635E+08 610.24 0.300 4.21273E+08 609.32 0.350 4.06828E+08 608.90 0.400 3.97178E+08 608.40 0.450 3.87735E+08 608.95 0.500 3.78530E+08 609.68 0.600 3.56828E+08 609.63 0.700 3.36215E+08 609.80 0.800 3.25655E+08 612.91 0.900 3.07612E+08 614.85 1.000 2.93322E+08 617.40 1.501 2.69420E+08 607.63 2.001 2.58911E+08 601.34 2.501 2.42177E+08 598.21 3.001 2.24976E+08 606.25 4.001 1.95546E+08 608.38 5.001 1.64363E+08 614.49 6.001 1.28220E+08 631.42 7.001 8.69308E+07 701.85 8.001 5.70425E+07 811.45 9.001 3.10542E+07 1005.75 10.004 9.48989E+06 1201.09 10.103 8.20480E+06 1203.41 10.203 7.02609E+06 1205.69 10.303 5.91694E+06 1208.49 10.403 4.90078E+06 1212.23 10.503 3.91891E+06 1215.92 10.603 2.90130E+06 1221.78 10.703 1.86214E+06 1229.85 10.801 0.OOOOOE+00 633.32 10.903 9.04572E+05 850.46 11.003 5.96011E+05 687.27 11.103 1.92314E+05 729.41 11.201 0.OOOOOE+00 729.41 46

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 TABLE A.2. M&E Of Double-Ended Cold Leg Slot Break (Ref. 7)

TIME MASS RATE ENTHALPY (sec) I (lbm/hr) (BTU/lbm) 0.000 0.00000E+00 541.01 0.050 2.98064E+08 541.01 0.101 3.72898E+08 541.05 0.151 3.85067E+08 542.47 0.201 3.79029E+08 543.22 0.251 3.70183E+08 543.76 0.301 3.74878E+08 544.14 0.351 3.71025E+08 544.31 0.401 3.72964E+08 544.41 0.451 3.69575E+08 544.43 0.501 3.69878E+08 544.41 0.601 3.59931E+08 544.31 0.701 3.57694E+08 544.27 0.801 3.54490E+08 544.35 0.901 3.45453E+08 544.38 1.001 3.30747E+08 544.49 1.501 2.98955E+08 548.16 2.003 2.72929E+08 554.51 2.503 2.34036E+08 558.66 3.003 2.07884E+08 560.08 4.003 1.85335E+08 568.49 5.002 1.30913E+08 664.36 6.002 1.11650E+08 668.39 7.002 8.98389E+07 694.06 8.002 6.76444E+07 741.56 9.002 4.24786E+07 875.19 10.002 2.76768E+07 1042.54 11.002 1.80674E+07 1151.04 12.002 1.19236E+07 1170.67 12.502 8.44249E+06 1218.50 13.002 6.06057E+06 1232.41 13.102 5.61456E+06 1237.68 13.202 5.18687E+06 1243.28 13.302 4.78194E+06 1249.10 13.402 4.39780E+06 1255.07 13.502 4.04016E+06 1261.09 13.602 3.70139E+06 1266.95 13.702 3.39254E+06 1272.70 13.801 3.09734E+06 1278.20 13.901 2.81988E+06 1283.44 14.000 2.30902E+06 1286.66 14.100 1.67070E+06 1291.28 14.200 9.65274E+05 1295.71 14.302 0.OOOOOE+00 1295.71 47

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 TABLE A.3. M&E of 2 ft2 Hot Leg Slot Break (Ref. 7)

TIME MASS RATE ENTHALPY (sec) [ (lbm/hr) I (BTU/lbm) 0.000 0.00000E+00 613.81 0.050 1.10796E+08 613.81 0.100 9.42579E+07 612.53 0.150 6.98021E+07 611.42 0.201 6.89816E+07 611.51 0.251 6.77608E+07 611.76 0.301 6.73058E+07 612.15 0.351 6.70943E+07 612.56 0.401 6.69765E+07 612.95 0.451 6.69765E+07 613.25 0.501 6.70075E+07 613.45 0.600 6.71865E+07 613.66 0.700 6.70277E+07 613.74 0.800 6.67854E+07 613.84 0.900 6.69105E+07 614.08 1.000 6.66056E+07 614.36 1.500 6.62200E+07 617.65 2.000 6.50634E+07 622.70 2.500 6.37368E+07 627.64 3.000 6.22294E+07 632.81 4.000 5.97740E+07 639.80 5.000 5.67888E+07 645.09 10.000 4.69104E+07 638.80 15.000 4.49484E+07 620.81 20.000 4.16312E+07 623.26 25.000 3.63978E+07 630.49 30.000 3.00131E+07 650.78 35.000 1.95409E+07 754.65 40.000 1.15828E+07 887.14 45.000 7.36814E+06 976.37 50.000 3.63610E+06 1170.83 50.500 3.01941E+06 1187.83 51.004 2.50180E+06 1200.69 51.504 2.44827E+06 1222.09 52.003 2.81536E+06 1213.20 52.503 3.11656E+06 1199.14 53.003 3.26076E+06 1193.33 53.501 3.26959E+06 1197.03 54.002 3.24266E+06 1200.38 54.501 3.08479E+06 1204.00 55.000 2.82859E+06 1210.45 55.500 2.42096E+06 1212.25 56.000 1.97414E+06 1216.56 56.500 1.69268E+06 1217.68 57.000 1.17721E+06 1226.11 57.500 5.38137E+05 1247.41 58.000 0.OOOOOE+00 1247.41 48

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX B HISTORY OF CCNPP CONTAINMENT ANALYSIS WITH GOTHIC (All materials in this appendix are echoed from and refer to Reference 3) 49

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1.1. BACKGROUND To provide a historic background, the evolution of the GOTHIC model for containment response analysis is summarized as follows (all calculations are revision 0000 unless revision is specified):

1) CA00028, "GOTHIC Versus COPATTA. An Analysis for Containment Response To Hot And Cold Leg Breaks With GOTHIC," 1995 This calculation contains the original GOTHIC LOCA models for the hot and cold leg breaks, which were developed and benchmark against the Bechtel COPATTA results.

2) CA00029, "GOTHIC Versus COPATTA. Analysis for Containment Response to MSLB with GOTHIC," 1996 This calculation contains the original GOTHIC MSLB model for the main steam line break, which was developed and benchmark against the Bechtel COPATTA results.

3) CA03393, "GOTHIC Versus COPATTA for CCNPP Containment Response," 1996 This calculation is similar to 1 but includes the reactor vessel to calculate the long term mass and energy transfer rates. This calculation completely decouples in-house analysis from COPATTA

4) CA03964, "Evaluation of Paint & Primer on Containment Response to DBAs," 1997 This calculation performs a parametric study on various paint and primer coating systems per CEU.

5) CA03558, "Effect of Time Step Size on Containment Pressure and Temperature in a LB-LOCA," 1997.

In this calculation, a parametric study is performed to investigate the effect of time step size for numerical integration on the peak containment pressure and temperature. The result was used in the subsequent calculations.

50

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

6) CA03491, "Containment Response Analysis to New Mass & Energy Rates Due to Higher Tcold," 1997 In late 1997, the cold leg temperature was raised from 548 F to 550 F (this was to maintain thermal efficiency, which had dropped due to SG tube plugging). A revised mass and energy for the DBAs were produced by CE/WEC and revised analysis was performed for containment response.

7) CA04340, "GOTHIC Versus COPATTA. Analysis of Containment Electrical Penetration Temperature Profile with GOTHIC," 1998 This calculation includes all the documents related to the passive as well as energized containment penetrations and includes the related models to the previously quality assured calculations. All the subsequent containment analysis use this model to provide the heat transfer response to EEU, which is responsible for Equipment Qualification.

8) CA03559, "Topical Report, GOTHIC Versus COPATTA. Model Qualification," 1998.

This calculation documents a Topical Report for GOTHIC. This is in partial fulfillment of requirement for in-house containment analysis. However, based on NRM's advice, the use of the GOTHIC code was justified based on a 10 CFR 50-59 presentation to safety committee.

9) CA04991, "Effects of Coating Systems on Containment Response to DBAs," 2000 In this calculation various coating systems (Ameron-66/Ameron-D6, Ameron-90, Keeler &

Long, and Carboline-890) per CEU were analyzed to determine their effect on containment peak pressure and temperature as well as the EQ profile. Ameron and a thicker coating assumption were determined to be the most conservative coating system and were used in all subsequent analysis.

10) CA05878, "Containment Response to DBAs for OSG and RSG," 2001.

In this calculation, a new set of MSLB mass and energy transfer rates for the replacement steam generator (RSG) was used. This set of data were produced by Areva (Framatome Technology Inc.) by using the RELAP computer code. The intention was to provide boundary and initial conditions for the resolution of GL 96-06, which deals with steam hammer in the containment air coolers.

51

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

11) CA05892, "Containment Response to OSG And RSG DBA for UFSAR," May 2002.

This calculation constitutes the bases for updating the UFSAR. It includes all the modifications including the steam generator heat sinks, the subsequent improvised heat sinks etc. It also contains a reasonably detailed information about the pertinent input data and includes the hard copy of all the references used in model development in support of the various input data.

Calculation CA05892 supersedes all previous containment response analysis calculations.

Since the production of CA05892, several calculational change notices (CCNs) were performed to address various issues, the majority of which deal with the changes in the containment heat sinks. For the sake of consistency, the purpose of each CCN is provided below:

11.1. CA05892-0001 This is a one-time analysis to determine the effect of the removal of a feedwater heater on the containment response 11.2. CA05892-0002 This CCN is the same as NEU-93-126-0002 dealing with the changes in passive heat sinks due to the Unit 2 steam generator replacement. Note that the changes in passive heat sinks due to the Unit I steam generator replacement are documented in NEU-93-126-0001.

11.3. CA05892-0003 This CCN responds to NRC's question regarding the assumption of MFIV closing on SGIS.

11.4. CA05892-0004 This CCN was originated to account for various other modifications in the passive containment heat sinks such as placement of metal boxes, replacement of grating and removal of vessel head shield, is pertinent to Unit 2 containment.

11.5. CA05892-0005 This CCN addresses two issues a) replacing the Unit 1 reactor vessel head and its effect on the heat sinks and b) performing modifications due to the changes in the auxiliary crane.

Additionally, this CCN uses a conservative set of values for the containment heat sinks (heat conductors) so that both Unit 1 and Unit 2 containments can be represented by one set of analysis.

52

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 11.6. CA06774, "Containment Response to LOCA & MSLB for Calvert Cliffs Units I and 2",

March 2007.

This calculation was originated to update heat sinks as described in Section 4.1.

11.7. CA06774, Rev. 0001, "Containment Response to LOCA & MSLB for Calvert Cliffs Units 1 and 2", February 2008.

This revision is being originated to change the time to RAS from 32 min (1920 sec) to 30 min (1800 see). This change was requested by Mechanical Engineering (IRE-021-644) to prevent the occurrence of vortex in RWT when sufficient static head diminishes as RWT begins to empty.

Vortex in turn increases the likelihood of air ingress in the ECCS pumps, degrading NPSH.

Although the change in the time to RAS was the only change actually implemented in the input file of the LOCA DBA, there has been another change, which is not implemented. This change is related to the removal of the containment scaffolding. As described in Reference 6 (reference is included in this calculation, which follows Appendix G)

12) CA06774, Rev. 0001, "Containment Response to LOCA and MSLB for Calvert Cliffs Units I and 2," March 06,2008.

This calculation is presently the latest case of record, supporting UFSAR. It re-analyzes the limiting DBAs, using the latest version of the GOTHIC code. The re-analysis incorporates such changes to the containment as the addition of the sump passive strainer, modifications of the Palfinger crane, and carbon steel removal from the pressurizer doghouse. This calculation while supersedes the results obtained in CA05892 - 0005, it is based on the same model used in CA05892-0005 with added modifications.

13) CA06774, Rev. 0002, "Containment Response to LOCA and MSLB for Calvert Cliffs Units I and 2 Sump Temperature," September 08,2008 Calculations I through 9 analyze MSLB and 3 LOCA cases, two Cold Leg events with the break located at the pump discharge for both events and one Hot Leg event. The only difference between the two Cold Leg break events was the single failure assumption, which resulted in crediting minimum or maximum safety injection. The Hot Leg LOCA assumes minimum safety injection. However, subsequent to the steam generator replacement, the containment response analysis documented only limiting DBA cases of Cold Leg LOCA with maximum safety injection (CL maxSI) and MSLB. That was because, these events were most limiting with respect to containment peak pressure and temperature as well as the EQ profile. Addition of the passive sump strainer and consideration of the safety injection pump NPSH has added yet another constraint to the containment response analysis. As such, Hot and Cold Leg LOCA events with minimum safety injection must also be analyzed to determine the effect on sump temperature.

53

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 To make CA06774, Rev. 0002 a standalone calculation, the results of CA06774, Rev. 0001 for MSLB are repeated in this calculation. Furthermore, it is shown that despite the corrections described in Section 1.2, the results obtained for CL maxSI in Rev. 0001 remain valid.

Therefore, those results are also repeated in this calculation.

14) CA06775, Rev. 0000, "VERIFICATION & VALIDATION OF GOTHIC 7.2A

15) CA07458, Rev. 0000, "Analysis of Containment Sump to Hot & Cold Leg LOCA DBAs For Calvert Cliffs Units I and 2", September 15, 2010 The fine print M&E data as produced by Westinghouse were used to originate a revised containment response to LOCA DBA's focusing on the long term cooling phase of the large break LOCA. The purpose of that analysis was to develop the sump water temperature profile for NPSH and chemical precipitants per GSI- 191

16) CA07634, Rev. 0000, "Containment Response Analysis To DBA LOCA for Procedure Upgrade," December 2011 This calculation documents the analysis of the containment response to maneuvers involving HPSI, LPSI, and CSP given various DBA LOCA's for the purpose of upgrading the plant emergency procedure (EOP-05).

17) CA07725, Rev. 0000, "ANALYSIS OF CONTAINMENT INTEGRITY IN DBA LOCA \ FOR CCNPP UNITS 1 & 2", JANUARY 19,2012 This calculation resolves the containment integrity issue due to the revised M&E produced by Westinghouse. The initial containment pressure was reduced by 1 psi.

18) CA07785, Rev. 0000, Verification and Validation of GOTHIC Rev. 8.0(QA), July 2012 This calculation documents the resolution of OD by reducing the initial containment pressure to a maximum of 1 psig to maintain the peak containment pressure below the T.S. limit of 50 spig.

19) CA07786, Rev. 0000, Containment Response Analysis In Support of LAR, July 2012 This is the present calculation. It is similar to #18 but extends the documentation of containment response to also include EQ. Since it supports the current plant procedure, the safety adjustment in this calculation takes place at RAS.

54

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX C TECHNICAL ASSUMPTIONS 55

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Three assumptions have been used in all calculation packages shown in Appendix B. Two of which are echoed from CA00028, Rev. 0000 (Calc. 1 of Appendix B):

• There is no evaporation from the containment pool into the containment atmosphere. While GOTHIC does calculate such rate of mass transfer, a small pool area is imposed to minimize the rate of evaporation. This assumption is made to be consistent with zero pool evaporation in COPATTA calculation (References 20 and 28.)

" Flow area, hydraulic diameter, friction, and inertial length of some flow paths, connecting flow boundary conditions to the containment are arbitrarily selected, rather than being rigorously calculated. This doesn't impact the results, while the goal of delivering or removing specified inventory is accomplished

" The third assumption is from CA05892, Rev. 0000 (Calc. 11 of Appendix B), which specifies the use of a drop diameter of 100 micron for high energy line break, per recommendation of the GOTHIC code User's Manual The list of references used in CA000028 are provided in this Appendix.

56

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 REFERENCES OF CALCULATION CA00028, REV. 0000, 1995

i. NPSD-35-P. "CEFLASH-4A, A FORTRAN IV Digital Computer Program for Reactor Blowdown Analysis," April 1977. Also CENPD-133P and Supplements 2, 4, and 5, "CEFLASH-4A, A FORTRAN IV Digital Computer Program for Reactor Blowdown Analysis," June 1985.

ii. ABB CE, "Computer Code Description and Verification Report for FLOOD3," FLOOD3-MOD1, February 4, 1988.

iii. CENPD-140A, "Description of the CONTRANS Digital Computer Code for Containment Pressure and Temperature Transient Analysis," R. C. Mitchell. June 1976.

iv. Bechtel TOPICAL REPORT BN-TOP-3, Rev. 4, "Performance And Sizing Of Dry Pressure Containment," Attachment B. October 1977.

v. EPRI RP4444-1, NAI 8907-02 Rev. 5, "GOTHIC Containment Analysis Package," Version 4.1. Numerical Applications, Inc. September 1994.

vi. Bechtel Letter NOPS95-322," Containment Pressure / Temperature Response to Hot Leg Break LOCA and Cold Leg Break LOCA - Data Letter," Bechtel File No. 0720-05847. April 4, 1995.

vii. BGE Memo, NEU 94-052,. "Resolution Of Ambiguity Regarding The Containment Initial Pressure," April 21, 1994.

viii. BGE Memo, NEU 94-193, From M. Massoud To W. J. Lippold. "Consideration Of Local Temperature Effects On Containment Analysis," June 29, 1994.

ix. BGE Memo, NEU 94-162, From M. Massoud To W. J. Lippold. "Determination Of Initial Containment Relative Humidity For Safety Related Containment Response Analysis,", May

26. 1994.

x. Bechtel Letter, "ECCS analysis, Containment Volume," Bechtel Job Number 6750, Bechtel File Number 6750-3404, CC-6546. April 1975.

xi. BGE Memo, NEU 94-169, From M. Massoud To W. J. Lippold. "Clarification Of Initial And Boundary Conditions For Containment Response Analysis," June 3, 1994.

xii. ABB CE Letter ST-95-095, "Final Transmittal of Long Term Data for Calvert Cliffs LOCA Containment Analysis," February 16, 1995.

xiii. ABB CE Letter ST-95-122, "Transmittal of Recorded Calculations for Calvert Cliffs 1 &

2 LOCA Containment Analysis," February 24, 1995.

57

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 xiv. ABB CE Calculation, "CEFLASH-4A LOCA Blowdown Containment Analysis For Calvert Cliffs Units 1 & 2 at 2754 MWt," Calculation No. 04/05-AS94-C-026. May 5, 1994.

xv. ABB CE Calculation, "BGE Calvert Cliffs Units 1 & 2 FLOOD3 LOCA," Calculation No.

04/05-AS94-C-027. Rev. 00; May 5, 1994. Rev. 01; February 7, 1995.

xvi. ABB CE Calculation, "BGE Calvert Cliffs Units 1 & 2 LOCA Containment Long Term

• Analysis," Calculation No. 04/05-AS94-C-030. Rev. 00, February 24, 1995.

xvii. BGE Letter From R. E. Denton To U.S. NRC, "10 CFR Part 21 Report; Non-Conservative Modeling Of Reactor Coolant System Sensible Heat For Containment Pressure Response Safety Analysis," January 10, 1995.

xviii. Bechtel Letter From R. B. Patel To W. J. Lippold, "Engineering Error Report Sensible Heat in Postulated LOCA Energy Release," NOPS-93-787, File: 0273, 0505. December 6, 1994.

xix. BGE Letter, NEU 95-127 From M. Massoud To W. J. Lippold. "Resolution Of RCS Metal Stored Energy,". May 1, 1995.

xx. Bechtel Letter From J. B. Roberts To W. J. Lippold, "Containment Response To Hot Leg &

Cold Leg Break LOCAs," Bechtel Job Number 11865, Bechtel File-Number 0815, NOPS95-510. June 26, 1995.

xxi. NRC Branch Technical Position ASB 9-2, "Residual Decay Energy for Light-Water Reactors for Long-Term Cooling," Rev. 2, July 1981.

xxii. BGE Letter, NEU 93-040 From Ian Sommerville To R. K> Bleacher, "EOP-5/FSAR Discrepancy on Spray Duration," February 2, 1994.

xxiii. BGE Letter ME-94-0187.011 From B. H. Scott To M. T, Finley, "Containment Air Cooler Capacity at Reduced SRW Flow," January 20, 1994.

xxiv. BGE Letter, ME 94-0606.011, From B. H. Scott To M. T. Finley. "Containment Analysis with Clean Air Coolers,", March 18, 1994.

xxv. MEU Calculation 95-0114, Rev. 00, "Evaluation Of SDC and CCW Heat Exchanger Thermal Performance To Support LOCA Analysis," March 22, 1995.

xxvi. NEU Letter NEU 93-203, From I. M. Sommerville and M. Massoud To M. J. Gancarz.

"Liner Shell Air Gap and New Heat Sinks Information for LOCA & MSLB Containment Response," July 23, 1993.

58

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 xxvii. Licensing Unit Letter L94-021, From Pat Furio To M. T. Finley. "Use Of Air Gap in Containment Pressure Analysis," January 21, 1994.

xxviii. Bechtel Calculation 0720-05847, 0815. "Containment Response to Hot Leg & Cold Leg Break LOCAs for UFSAR," Bechtel Job No. 11865. NOPS95-373. April 21, 1995.

xxix. BGE Calculation 000-TH-9302, Rev. 01. "Calculation of Delay Time for the Containment Spray," June 30, 1994.

xxx. NUS calculation 4N63-M-01, Rev. 1. "Unit 2 ECCS Hydraulic Analysis," (BGE Calculation M-92-1 11.) May 20, 1992.

xxxi. CCNPP UFSAR, Rev. 17.

xxxii. C. C. Lin, et. al., "CONTEMPT4/MOD4 A Multicompartment Containment System Analysis Program," NUREG/CR-3716. BNL-NUREG-51754, March 1984.

xxxiii. BGE Calculation "LOCA Containment Response Comparison Between GOTHIC And CONTEMPT," NC-93-008, Rev. 0.

xxxiv. CCNPP UFSAR 6.4 Containment Spray System Table 6-6 Page 6.28.

xxxv. Performance and Sizing of Dry Containments, BN-TOP-3, Revision 4 (Draft), October 1977, Page 4a. Bechtel Power Corporation, San Francisco, California.

xxxvi. Brown, R. and Lewis J. York, "Sprays Formed By Flashing Liquid Jets," AIChE Journal, Vol. 8, No., 2, May 1962, p. 149.

xxxvii. Warner, C. F. and D. W. Natzer, "An Investigation of the Flow Characteristics of Two

-Phase Flow Converging Diverging Nozzles," ASME Paper 63-WA-192, 1963.

59

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX D INPUT DATA DESCRIPTION

[All materials in this appendix are echoed from and refer to Reference 3 (CA07458, Rev. 0000)]

60

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4 INPUT DATA The only changes made to the GOTHIC models of the AOR for the high sump water temperature cases include a) M&E as identified in Table 1.1, b) early termination of LPSI, and c) Pressure set point of 2.8 psig for termination of the 2 nd spray. All other data remain the same as used in' the analysis of record (Reference 1). Most of discussion in this section is pertinent to high sump water temperature. For the low sump water temperature case (cx vac) data are identified in Table 4.12 and explained in the relevant sub-sections of the text.

4.1 CONTAINMENT GEOMETRICAL DATA Containment. To be consistent with the approved methodology-of COPATTA, the containment is represented by one lumped volume (V1)4 to which various boundary conditions representing for example break flow rate, safety injection, and spray flow are connected. A lumped volume is in contrast to a subdivided volume (for three dimensional analysis) and should not imply that water and steam are mixed uniformly to produce a mixture at thermal equilibrium. On the contrary, in a GOTHIC lumped volume, two separated regions of water in the pool and steam mixed with non-condensable gases in the vapor region of the lumped volume may coexist, resulting in a water level which is traced throughout a transient. Under non-equilibrium conditions, each region would have its own temperature during transients. However, there is no temperature distribution within each region as it is assumed that fluid in each region is fully mixed, thus represented by only one temperature. Mass and energy are transferred at the interface of the two regions in addition to the exchanges at the interfaces between vapor and the drop fields if present. Only one pressure is calculated at the center of the lumped volume and is affected by the static head if water level rises beyond the volume mid-plane.

Containment Free Volume: CCNPP containment is of large dry type with a nominal free volume 3

of 2 x 106 ft3 . A 1975 letter of the architect engineer specifies an internal volume of 1.995E6 ft with accuracy of 0.3%, hence a low internal volume of 1.989E6 ft3. Since addition and removal of objects to or from the containment throughout various refueling outages have been closely monitored, the above value has been reduced to a value of 1,988,614 ft3 to reflect the change to the free volume. This value is conservatively used for the net free volume in the containment response analysis. Addition of solid objects (such as ladders, for example) to the containment has competing effects on the peak pressure. This is because the volume of the object reduces free volume of the containment for vapor expansion, increasing the magnitude of containment peak pressure. However, surface area of the object may assist in absorbing heat, thus reducing pressure.

In several cases, while penalty was taken for objects added to the containment, conservatively no credit was taken to treat the object as a GOTHIC heat conductor.

Containment Height: The actual inside containment height of 181' 73/4"' per UFSAR drawing is used in the analysis. This represents the vertical distance between the top of the containment, dome to the surface of the basemat, measured at the centerline.

GOTHIC benchmark of the CVTR test shows lumped parameter approach is more conservative than subdivided volume 61

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Hydraulic Diameter: 'In the original CCNPP GOTHIC model (circa 1994) the hydraulic diameter was based on Dh = 4V/A where V is the free containment volume and A is flow area in horizontal plane). Since the flow area changes with height, an average value of 107.7 ft was determined (that is smaller than the actual inside diameter of the containment cylindrical shell of 130 ft). Recent GOTHIC guidelines suggest using A = AConductor = 319,447 ft2 instead of flow area. Fortunately, hydraulic diameter has rather insignificant effect on the calculated parameters. For example, the updated value, calculated as Dh = 4 x 1,988,614/319,447 = 25 ft is 4 times smaller than the value used in the all containment response analyses. Yet, trail runs indicate that using the smaller value of 25 ft increases the peak containment pressure only by about 0.08% and has no discernable effect on the sump water temperature. The effect on the peak vapor temperature is similarly minor.

L/V Interface Area: To maximize the containment pressure and vapor temperature, the liquid vapor interface area in all containment response calculations has been set to a value of 1.00 ft2 .

Changing this value to DEFAULT reduces the cold leg LOCA peak pressure by about 3.5% and peak temperature by about 1%. This reduction is at the expense of the sump water energy, as the exchange at the interface raises the peak water temperature by nearly 5%. Fortunately, this increase in water temperature occurs early in the event (i.e., less than 1000 sec from the start of the transient) thus has no effect on the NPSH of the ECCS pumps and in longer term (i.e., greater than 5000 sec from the start of the transient) the revised profile falls slightly below the AOR profile.

The effect on peak pressure and water temperature of the hot leg LOCA is insignificant due to the short duration to reach the peak values.

62

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.2. INITIAL CONDITIONS Containment Initial Pressure: Plant Technical Specification 3.6.4 specifies a pressure range of 13.7 - 16.5 psia ( 1.8 psig) for initial containment pressure. The higher end of this range has conservatively been used in all containment response analyses. Since the revised M&E results in a containment peak pressure, which exceeds the Technical Specification limit of 50 psig presently, CCNPP is operating under an administrative limit of 1 psig until a permanent resolution is found.

The operability limit of 15.7 psia imposes no operational constraint as the inspection of historical data indicated the containment pressure remains well below this value. For CCNPP, lowering the initial pressure from 16.5 psia to 14.7 psia reduces the peak containment pressure by 2.3 psi.

For the low sump water temperature case (cx vac), the initial containment pressure is assumed to be atmospheric.

Containment Initial Temperature: This value is conservatively assumed to be 120 F, per CCNPP Technical Specification 3.6.1.5. However, the value used in the analysis is 125 F, which includes 5 F for both instrument and measurement uncertainty.

For the low sump water temperature case (cx vac), the initial vapor temperature is assumed to be at 120 F (Reference 4). An initial temperature of 90 F was also analyzed Containment Initial Relative Humidity: The initial relative humidity of the containment vapor space used in all analysis is 20%. This is a conservative value as lower relative humidity results in higher amount of non-condensable gases in the containment. This in turn increases peak pressure for two reasons, a) it increases the partial pressure of air and b) it degrades condensation on colder surfaces of containment heat sinks. This value was obtained statistically from the plant historical data.

For the low sump water temperature case (cx vac), initial relative humidity is assumed to be 100%. Higher relative humidity combined with lower initial pressure result in earlier appearance of partial vacuum in containment

)

Initial Water Volume Fraction: Since the containments of CCNPP are of large dry type, the initial water volume fraction is set to zero.

For the low sump water temperature case (cx vac), the initial water volume fraction is also taken as zero.

63

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.3 FLOW PATH Flow path parameters: Flow path, or junctions, are terms applied to connections between two volumes or one volume and a boundary condition. A flow path requires specification of its inertial as well as friction lengths, flow area, frictional loss coefficient, and height and elevation of each end. In thermal hydraulic analysis, mass and enthalpy are calculated at the center of a lumped parameter while velocity is calculated at the junction connecting two lumped volumes. Since the containment is modeled as one node (lumped parameter), there is no inter-nodal velocity to be calculated. Still, for determination of such factors as drop deposition, mass transfer coefficient, and heat transfer coefficient, the flow velocity in the lumped volume is required. For this reason, GOTHIC uses the junctions parameters such as length and flow area to calculate a volume average velocity:

Z LiViAi V

where Li, Ai, and Vi are the flow path inertial length, flow area, and flow velocity, respectively and V is the containment volume. Specification of unreasonably large junction inertia has cascading effects as it a) results in the calculation of high volume velocities, b) high volume velocity results in calculation of high drop deposition due to impaction, c) large drop size reduces the drop mass in the atmosphere, d) less drop mass results in slightly higher P & T. In this analysis, physically based values for flow path inertia are used. No choked flow option is chosen at any junction. All forward and reverse frictional loss coefficients are set to zero except for the break junction in long-term M&E calculations, which is set to unity.

64

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.4 BOUNDARY CONDITIONS Various GOTHIC boundary conditions for three types of LOCAs used in the analysis are discussed below. These include two cases of cold leg and three cases of hot leg LOCA (See figures)

Boundary Conditions for cx: There are 10 flow boundary conditions for this event including:

- Break flow rate of blowdown, reflood/post reflood (IF)

- Spray flow rate pre-RAS (2F)

- Spray flow rate post-RAS (3F & 4C)

- SIT nitrogen inventory (5F)

- Short & long-term spillage from break to sump (6F)

- Spillage from SIT to sump (7F)

- Spray flow rate post-RAS (8F & 9C)

- Spillage from broken loop to sump (10F)

- Safety injection to vessel pre-RAS (13F)

- Safety injection to vessel post-RAS (1 IF & 12 C)

Boundary Conditions for ci: There are 7 -flow boundary conditions modeled including:

- Break flow rate of blowdown, reflood/post reflood, and long-term cooling phases (IF)

- Spray flow rate pre-RAS (2F)

- Spray flow rate post-RAS (3F & 4C)

- SIT nitrogen inventory (5F)

- Spillage from SIT to sump (6F)

- Safety injection to vessel post-RAS (8F & 9C)

- Safety injection to vessel pre-RAS (7F)

Boundary Conditions for hi: There are 5 flow boundary conditions modeled including:

- Break flow rate of blowdown, reflood/post reflood, and long-term cooling phases (IF)

- Spray flow rate pre-RAS (2F)

- Spray flow rate post-RAS (3F & 4C)

- Safety injection to vessel pre-RAS (5F)

- Safety injection to vessel post-RAS (6F & 7C)

Boundary Conditions for hhx: There are 7 flow boundary conditions modeled including:

- Break flow rate of blowdown, reflood/post reflood, and long-term cooling phases (IF)

- Spray flow rate pre-RAS (2F)

- Spray flow rate post-RAS (3F & 4C)

- Safety Injection pre-RAS (5F)

- Safety Injection post-RAS (6F and 7C)

- Spray pre-RAS (8F & 9C)

- Spray post-RAS (1OF) 65

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Boundary Conditions for hhi: There are 5 flow boundary conditions modeled including:

- Break flow rate of blowdown, reflood/post reflood, and long-term cooling phases (IF)

- Spray flow rate pre-RAS (2F)

- Spray flow rate post-RAS (3F & 4C)

- Safety injection to vessel pre-RAS (5F)

- Safety injection to vessel post-RAS (6F & 7C)

Boundary conditions for the low sump water temperature case are identical to the case cx, detailed above.

The GOTHIC schematics of each model representing various cases of LOCA are shown in Figures 4.4.1 through 4.4.5. Figure 4.4.6 shows the MSLB diagram. The MSLB event is not analyzed but retained in this calculation from the AOR.

Flow rates for the spray boundary conditions are discussed in Section 4.5 and for the break and spillage in Section 4.6.

66

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Feb/12/2007 11:20:55 GOTHIC Version 7.2a(QA) - January 2006 File: C:\TMP\CRA\UFSAR_2007\LOCA\clx Figure 4.4.1. GOTHIC nodal diagram of LOCA DBA (cx) 67

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 cli AMERON 66/D6 Aug/23/2008 12:36:10 GOTHIC'Version 7.2a(QA) - Januay 2006 File: C:XMMBACK 0O8\MM* Bac 030708\TMP\WORK_2008\CRA\SUMP\LOCACASES\RSG~cli 7F 2F 5F 1IH2H 4C 1F I i 0I

)~

F2I IF3 I V7 F1ýF11 12C19 Fl8 F F Figure 4.4.2. GOTHIC nodal diagram of LOCA DBA (ci) 68

\

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 hli Ameron 66/D6 Aug/2312008 12:33:56 GOTHIC Version 7.2a(QA) - January 2006 File: C:\MMBACK 08 08XMMBack_030708\TMP\WORK_2008\CRA\SUMP\LOCACASES\RSGuhli F 2F 1H2H 4C 1F IFI -

01 I 2 i I I I iF I2 I'I I

I I

- - - I F ie F46 f i 7C I 15 F171 199 18]I I I F F Figure 4.4.3. GOTHIC nodal diagram of LOCA DBA (hli) 69

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud / ECP-11-001022 August 2012 Uses WEC data for M&E, Spill, Dec-Sen Jul/30I2010 10:49:28 GOTHIC Version 8.0(betal) - Apr 2010 File: C:\MMFiles\TMP\CRA\SUMPTESTWEC\HL\HHX~hhxWEC.GTH 1 H2H F-11 1-2] 13]

F14 F16] I I I I 15 17- F18] I I 191 I. I I I I I I I Figure 4.4.4. GOTHIC nodal diagram of LOCA DBA (hhx)

(Case is analyzed with GOTHIC 7.2a) 70

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Uses WEC data for M&E, Spill, Dec-Sen Jul/3012010 10:55:03 GOTHIC Version 8.0(betal) - Apr 2010 File: C:\MM_Files\TMP\CRA\SUMPTESI'WEC-HL\HHI~hhiWEC.GTH 1 H2H F10-F12 F13]

F14 F16]

15 F17] 18]

F19 Figure 4. 4.5. GOTHIC nodal diagram of LOCA DBA (hhi)

(Case is analyzed with GOTHIC 7.2a) 71

CONTAINMENT RESPONSEANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Feb/12/2007 12:05:20 GOTHIC Version 7.2a(QA) - January 2006 File: C:\TMP\CRA\UFSAR_2007\MSLB\FinaMI F 3F F2 F-r R QC _

Fiur 4..6 GOHCndldara V819 fML A r 46Oi 72

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.5 HEAT SINKS Ultimate Heat Sinks for the active heat sinks (CAC/SRW and SDC/CCW) is the Chesapeake Bay.

These systems are discussed in this section followed by description of the passive heat sinks.

4.5.1 ACTIVE HEAT SINKS Containment Air Coolers (CACs): The rate of heat removal by CACs is calculated from a duty table used as GOTHIC forcing function. Since the CAC speed changes, two tales have been used for CAC rate of heat removal pre-RAS (IC) and post-RAS (2C). In the production of the tables (by MEU), a conservatively high fouling factor of 0.0005 F-ftWhr/Btu is assumed. A pressure set point of 4.75 psig for CAC activation and an actuation delay of 35 seconds are used. The rate of heat removal of one unit of the containment air coolers is shown in Table 4.1.

Number of Containment Air Coolers: Number of CACs in the case of a LOCA is always one train of air coolers (i.e., 2 CACs) regardless of the assumed single failure. This is due to the fact that the single failure loss of off-site power results in the loss of one train of SRW. In the case of a MSLB, 4 CACs are available due to the assumed feedwater-related single failure.

Pressure Set Point For Actuation: CACs are actuatedon a pressure set point of 19.45 psia.

CAC Delay For Actuation: CACs are actuated with a delay of 35.9 seconds after the pressure set point is reached. This accounts for 0.9 seconds signal delay.

SRW Temperature: Service Water (SRW) temperature is not directly used in the GOTHIC calculations, (nor in CONTRANS or COPATTA modeling CCNPP containment response). This is because presently, the CACs are not explicitly modeled in GOTHIC. However, the SRW

,temperature indirectly affects containment response due to the specified heat removal rate of the CACs. Mechanical Engineering (MEU) has calculated the rate of heat removal by one CAC conservatively assuming a SRW temperature of 105 F. The tabulated data calculated by MEU is then used as a forcing function and multiplied by the number of credited CACs. For example, forcing function values if multiplied by 2 represent the rate of heat removal of one train of CAC.

SRW Flow Rate, Pre-RAS: Modification of the SRW system resulted in a reduction of the pre-RAS flow rate to 1800 GPM for each CAC train. However, the rate of CAC heat removal in this period is conservatively calculated at a flow rate of 1400 GPM. The SRW flow rate doesn't directly enter into the GOTHIC calculations but it indirectly affects containment response via the heat removal rate of the CACs.

SRW Flow Rate, Post-RAS: For the post-RAS in case of a LOCA, the flow rate to the CAC trains is established at 1900 GPM. The SRW flow rate does not enter into GOTHIC calculations as it indirectly affects containment response through the heat removal rate of the CACs, which is activated after RAS.

Air Flow Rate: Flow rate of containment mixture through each of the CACs is 55,000 CFM.

73

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 CAC Heat Removal Rate For High Sump Water Temperature: CAC heat removal rate is conservatively based on a fouling factor of 0.0005 hr.ft2 .F/Btu so that specification of a fouling factor in GOTHIC is not necessary. Table 4.5.1 (Figure 4.5.1) shows both pre-RAS and post-RAS heat removal rates for one unit of fouled CAC.

Table 4.5.1. Heat Removal Rate of One Fouled Containment Air Cooler Unit Saturation CAC Heat Removal Rate in Btu/h (Btu/s)

Temperature (@ two different SRW flowrate)

(F) 1400 GPM - Pre-RAS 1900 GPM - Post-RAS 110 1.143E6 (317.5) 1.224E6 (340) 120 3.719E6 (1,033) 4.029E6 (1119.2) 130 6.671E6 (1,853) 7.271E6 (2019.7) 140 10.027E6 (2,785.3) 11.007E6 (3,057.5) 150 13.749E6 (3,819.2) 15.191E6 (4,219.7) 160 17.799E6 (4,944.2) 19.844E6 (5512.2) 180 26.781E6 (7,439.2) 30.287E6 (8,413.0) 200 36.639E6 (10,177.5) 41.964E6 (11,656.6) 225 49.736E6 (13,815.5) 57.727E6 (16,035.3) 250 63.188E6 (17,552.2) 74.078E6 (20,577.2) 270 73.907E6 (20,529.7) 87.201E6 (24,222.5) 275 76.554E6 (21,265.0) 90.454E6 (25,126.1)

Service water inlet I emperature kr): IV:)

Steam/Air Flow Rate (CFM): 55,000 CAC Fouling Factor ( hr-Vt2-F/Btu): 0.0005 1.E+08 9.E+07 8.E+07 M

7.E+07

,-S 0

6.E+07 E

5.E+07

0) 4.E+07 4,i 3.E+07 Cr 2.E+07 1.E+07 O.E+00 100 150 200 250 300 Saturation Temperature (F)

Figure 4.5.1. Rate of Heat Transfer of One Fouled Containment Air Coolers 74

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 CAC Heat Removal Rate For Low Sump Water Temperature: Application of the fouled CACs for the low sump water temperature case is non-conservative. Therefore, the heat removal rate of a clean CAC is used. Similar to the high water temperature case, the heat removal rate is based on an inlet Service Water temperature of 105 F. The clean and fouled CAC profiles were calculated in the early 1990s when sump water temperature was not an issue. Therefore, MEU used the maximum temperature of 105 F for water leaving the EDG cooler and entering the CAC secondary side. Due to time constraint, production of a new CAC profile based on cooler Bay Water temperature of 40 F was not possible. This shortcoming was remedied by a) ignoring single failure of a loss of one train of SRW and assuming that all four CAC units are available for heat removal and b) noting that while ATLMTD increases for colder stream flowing in the CAC tubes, for constant tube velocity the heat transfer coefficient decreases in the colder stream (due to higher viscosity). Therefore, using the zero fouling profile and four CACs thought to result in reasonably conservative low sump water temperature. Similar to the full fouling case, the rate of heat removal is specified as a GOTHIC forcing function.

Table 4.5.2 (Figure 4.5.3) includes both pre-RAS and post-RAS heat removal rates for a fouled CAC. In Table 4.5.2, an arbitrary low temperature of 40 F corresponding to zero rate of heat removal was added in order to prevent abnormal termination of GOTHIC computations if vapor temperature happens to drop below 110 F.

Figure 4.5.2 compares rate of heat removals of a clean versus a fouled CAC for both pre- and post-RAS cases.

1.40 E+08

. 0 - Clean, pre-RAS 1.20E+08 - Clean, post-RAS -

-" - - - Fouled, pre-RAS 1.OOE+08 -Fouled post-RAS 8.OOE+07 -- --

-r M 6.OOE+07 ----

ý0 4.OOE+07 "2.OOE+07 O.OOE+O0 100 150 200 250 300 Temperature (F)

Figure 4.5.2. Comparison of Rate of Heat Removal for Clean vs. Fouled CAC 75

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.5.2. Heat Removal Rate of One Clean Containment Air Cooler Saturation CAC Heat Removal Rate in Btu/h (Btu/s)

Temperature (@two different SRW flowrate)

(F) 1400 GPM - Pre-RAS 1900 GPM - Post-RAS 40 0.00 (0.00) 0.00 (0.00) 120 4.217E6 (1,171.4) 4.829E6 (1,341.40) 130 7.697E6 (2,138.0) 8.882E6 (2,467.20) 140 11.93E6 (2,785.3) 14.08E6 (3,911.11) 150 16.16E6 (4,488.8) 19.28E6 (5,355.55) 160 21.60E6 (6,000.0) 26.46E6 (7,350.00) 180 32.48E6 (9,022.2) 40.83E6 (11,341.6) 200 45.75E6 (12,708.3) 60.10E6 (16,694.4) 225 62.34E6 (17,316.6) 84.19E6 (23,386.1) 250 79.47E6 (22,075.0) 111.64E6 (31,011.1) 275 96.60E6 (25,166.6) 139.09E6 (38,636.1)

Service water Inlet I emperature, r: IUD Steam/Air Flow Rate, CFM: 55,000 CAC Fouling Factor, hr-ft2-F/Btu: 0.0000 1.60E+08 1.40E+08

- -- Pre-RAS 3 1.20E+08

- Post-RAS w 1.OOE+08 8.OOE+07 w 6.OOE+07 0

4.OOE+07 2.OOE+07 O.OOE+00 100 150 200 250 300 Temperature (F)

Figure 4.5.3. Rate of Heat Transfer of One Clean Containment Air Coolers 76

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Spray System: There are two modes of operations for the containment spray, pre-RAS and post-RAS. In pre-RAS mode of operation, the source of water is the RWT, thus the stream has a fixed injection temperature. The flow rate and the RWT liquid temperature as well as the set point for operation and the associated delay are specified for the pre-RAS spray. Since the RWT is located outside the containment, the temperature of its water inventory closely follows temperature of the environment. Similar to all other safety analyses, a temperature of 110 F is used for the RWT water. In the post-RAS mode of operation, the. spray temperature is determined by the SDC-HX and the sump liquid temperature, as the sump is the source of inventory for the spray in long-term cooling phase of a LOCA.

Containment Spray Delay For Actuation: The delay in the appearance of atomized spray droplets inside the containment atmosphere, after the CSAS set point is reached, is due to the following factors a) signal delay, b) the ECCS sequencing logic, and c) the time required to fill the containment spray pipes, riser, and header. The containment spray delay used in the containment response analysis for LOCA is 70.9 seconds and for MSLB is 62.9 seconds, respectively. The reason for different spray delay is the assumption of the Loss of off-site Power (LOOP) in the case of a LOCA, and the availability of off-site power in the case of a MSLB.

Containment Spray Flow Rate: The rated flow rate used in the analysis is conservatively 1250 GPM per spray train. This flow rate is about 8% less than the nominal value of 1350 GPM.

Containment Spray Temperature Pre-RAS: Since the inventory is provided by the RWT, the Technical Specifications temperature of 110 F is used. This includes 5 F uncertainty.

Containment Spray Temperature Post-RAS: In the case of a LOCA DBA, following RAS, the ECCS suction is switched to the containment sump. Therefore, the ECCS suction temperature is the sump temperature. For post-RAS, the ECCS spray flow is passed through the shutdown cooling heat exchanger (SDC-HX) to reduce the spray temperature.

Containment Spray Efficiency or Effectiveness: Such efficiency is used in both CONTEMPT and COPATTA codes and is defined as a function of a ratio of containment atmosphere steam mass to containment atmosphere air mass as shown in Table 4.2. In earlier models, this table was implemented and used as a forcing function for a spray nozzle. However, this table was later removed from the GOTHIC model, as condensation degradation due to the presence of non-condensable gases is internally accounted in the GOTHICS solution of the drop models.

Number of Containment Spray Trains: The number of trains depends on the single failure assumption as shown in Table 1.1. The spray height is close to the actual containment height.

Spray Actuation Set Point: The pressure set point for spray actuation signal is conservatively assumed to be 19.45 psia (4.75 psig). This accounts for 0.5 psi instrument uncertainty.

Pressure Set Point To Shut off Containment Spray: In case of the cx that two containment sprays are credited, one spray is terminated when pressure drops back to a set point of 2.8 psig.

77

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Spray Height: The spray height used in the GOTHIC model is slightly larger than the volume using the actual volume height makes no difference on the results. In the future models, the actual volume height will be used.

Spray drop diameter is an important input, required by GOTHIC. The older computer codes such as CONTRANS and COPATTA did not require this input. If a large diameter is specified, drop travels faster than smaller droplets and joins the pool. This shortens the time for the larger drops to effectively condense steam. On the other hand, smaller drops may actually suspend in the vapor space and remove heat to eventually vaporize. However, the vaporization of smaller droplets leads to mass addition to the vapor space. As a result, there is not a clear cut effect between containment peak pressure and the spray drop diameter as it would depend on a specific problem. The GOTHIC manual suggests the use of the actual data provided by the spray nozzle manufacturer, if available. In cases that such data may not be feasible to obtain, the manual recommends a drop diameter of 1000 micron to be used. The CCNPP UFSAR specifies a drop diameter of 2.87E-3 ft (850 .t or 0.0344 in), which agrees well within 12% with the recommended value of 1000 p. = 0.1 cm = 0.03937 inch. However, Table 6-6 of UFSAR, Rev. 26, specifies a drop diameter of 700 p. UFSAR, Rev. 26 page 6.4-4 suggests 125% of the mass mean diameter (or 850 pt) per ORNL-TM-2412, which is more conservative (i.e., leading to higher peak pressure).

Therefore, this value is specified in Table 2 of the corresponding boundary condition (BC # 2F). ,,

In the earlier models, a spray nozzle was used. This was later removed as specification of drop diameter in Table 2 of BC would render spray nozzle unnecessary, as there is no flow fraction.

Table 4.5.3. Containment Spray Efficiency Steam Mass/Air Mass Spray Efficiency 0.00 0.730 0.10 0.735 0.20 0.745 0.30 0.765 0.40 0.775 0.50 0.790 0.60 0.810 0.70 0.830 0.75 0.843 0.80 0.860 0.85 0.880 0.915 0.923 0.95 0.940 1.00 0.960 1.05 0.973 1.10 0.983 1.15 0.990 1.20 0.995 1.25 1.000 AS described in tne text, this table is usedi in IJUO-A 1 IA ana in tne earlier versions of CCNPP GOTHIC model but was later removed from the GOTHIC model 78

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Sump Cooling: In CCNPP, the sump cooling takes place by the action of spray pumps, passing sump water through the shutdown cooling (SDC) heat exchanger. The component cooling water heat exchange (CCW-HX) is the heat sink for SDC-HX. The Chesapeake Bay is the heat sink for CCW-HX. The SDC-HX as well as CCWHX are modeled in GOTHIC as cascaded (double) heat exchangers (1H2H).

Primary Heat Exchanger (SDC-HX): The COPATTA code requires the overall heat transfer coefficient (U) to be specified as input. This is then used in conjunction with the heat exchanger effectiveness relations (hard-wired in COPATTA) to determine the outlet temperatures. Since no internal calculations are performed in COPATTA, changes in U with time is approximated as a step function. The first value for U is used for the period ranging from RAS to the input-specified time, 9. The second value is then used from 0 to the end of analysis time. While, GOTHIC provides variety of options, the same approach used by Bechtel is also used in the GOTHIC models to follow the NRC approved methodology. Bechtel assumes 0 = 10,000 seconds.

Number of SDC-HXs: The number of SDC-HXs depends on the assumed single failure. There is one CCW-HX per each SDC-HX. For cx there are two trains of SDC/CCW-HX available.

Percentage of Total Tubes Plugged: Although the RCS coolant and the CCW flow streams are chemically controlled, in the analysis to find U as used in COPATTA, it is conservatively assumed that 5% of the SDC-HX tubes are plugged.

Heat Transfer-Area Per Each SDC Heat Exchanger: Design Engineering (DEU) specifies the heat transfer area per heat exchanger, considering 5% tube plugging, as 4990 ft 2. For cx, total available surface area would be 9980 ft2 , corresponding to two SDC-HXs.

Overall Heat Transfer Coefficient < 10,000 Seconds: COPATTA uses an overall heat transfer coefficient of 206 Btu/ ft-hr-F. In GOTHIC tube-side and shell-side heat transfer coefficients of 538.80 and 881.64 Btu/ft2 -hr.F, respectively are used. These result in conservative value for the overall heat transfer coefficient for both cases of high and low sump water temperature as shown in Table 4.5.3-1 and 4.5.3-2.

Overall Heat Transfer Coefficient > 10,000 Seconds: COPATTA uses an overall heat transfer coefficient of 195 Btu/ ft2.hr.F. In GOTHIC tube-side and shell-side heat transfer coefficients of 481.39 and 872.79 Btu/ft2.hr-F, respectively are used. These result in conservative value for the overall heat transfer coefficient for both cases of high and low sump water temperature as shown in Table 4.5.3-1 and 4.5.3-2.

Flow Rate of Coolant: The CCW flow rate per heat exchanger is given as 8.9596E5 Ibm/hr. In the case of a LOCA, the total CCW flow to the heat exchangers is 1.79192E6 Ibn/hr.

Fouling Factor: Both tube-side and shell-side are conservatively assumed to be fouled, having a maximum fouling factor of 0.0005 ft2 .hrF /Btu.

79

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Number of CCW-HX: The number of CCW-HXs depends on the single failure. There is one CCW-HX per each SDC-HX. For cx, two trains of CCW/SDC-HX are available.

Percentage of Total Tubes Plugged: Since unfiltered Bay water flows in the CCW tubes, it is conservatively assumed that 10% of the CCW-HX tubes are plugged.

Heat Transfer Area Per Each Heat Exchanger: Due to the tube plugging, the effective heat transfer area per active spray loop is 5166 ft2 . Total heat transfer area for the case of cx is 10,332 ft2, corresponding to two heat exchangers.

Inlet Temperature of CCW To SDC-HX: This input data is not used by GOTHIC. It is the calculated outlet temperature of the CCW..

Overall Heat Transfer Coefficient < 10,000 Seconds: COPATTA uses an overall heat transfer coefficient of 288 Btu/ft2 .hr.F. In GOTHIC tube-side and shell-side heat transfer coefficients of 1372.12 and 721.38 Btu/ft2 .hr.F, respectively are used. These result in conservative value for the overall heat transfer coefficient for both cases of high and low sump water temperature as shown in Table 4.5.3-1 and 4.5.3-2.

Overall Heat Transfer Coefficient > 10,000 Seconds: COPATTA uses an overall heat transfer coefficient of 281 Btu/ft2 -hr-F. In GOTHIC tube-side and shell-side heat transfer coefficients of 1403.41 and 758.92 Btu/ft2 .hr.F, respectively are used. These result in conservative value for the overall heat transfer coefficient for both cases of high and low sump water temperature as shown in Table 4.5.3-1 and 4.5.3-2.

Flow Rate of Coolant: Service Water flow rate per heat exchanger is given as 2.74E6 Ibm/hr. In the case of a LOCA, the total secondary side flow rate is 5.48E6 Ibm/hr.

Fouling Factor: The shell-side is assumed clean, having zero fouling factor. Tube-side, which is exposed to bay water is assumed to be fouled, having a fouling factor of 0.00105 ft 2-hr.F/Btu.

80

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.5.2 PASSIVE HEAT SINKS Heat absorption in the containment structure and internals are accounted for by using GOTHIC heat conductors in the form of slabs (i.e., one dimensional heat conduction in the Cartesian coordinates) defined by the same material properties, volume, and surface area as the intended heat sinks. It is assumed that containment passive heat sinks are initially at thermal equilibrium with containment atmosphere, hence are at the same temperature as vapor. GOTHIC thermal conductors also represents some heat sources in the containment such as in the cavity region, which are initially at higher temperature than vapor. These are also modeled as heat sinks, which are initially at higher temperature than the initial vapor temperature.

Thermal conductor data are continuously updated to represent the actual materials in the containment. Changes made in the containment heat sinks by removing or adding materials to the containment have been the primary reason for various revisions to the containment calculations in the past few years. In updating the GOTHIC model to account for such changes, whenever there have been different values for the surface area or thermal conductors in Unit 1 versus Unit 2, the lower value has been conservatively used so that one set of GOTHIC input file can be used represents the thermal conductors of both units.

Heat Conductor Data: Heat conductors include the concrete cylindrical wall and dome with steel liner, structural materials, unlined concrete, and containment internals. These structures are shown in Table 4.5.4. In the CCNPP containment response analyses, no credit is taken for the concrete floor because following the break, the concrete floor is covered by hot RCS inventory, precluding any steam condensation. In practice, heat transfer from the liquid to the floor reduces the sump water temperature. However, this secondary effect on the performance of the containment spray is conservatively ignored. As shown in Table 4.5.4, a total of 19 heat sinks in the containment are credited for heat absorption in a LOCA. For MSLB, Table 4.5.5 shows that a total of 21 heat sinks are credited. The reason for the difference in the number of credited heat sinks is described in the discussion regarding the containment sump strainer.

The largest heat sink is the containment cylindrical shell and the associated dome.-, Containment electrical penetrations and other sensitive electrical equipment are represented by conductors 20 through 29. Equipment environmental qualification program (EQ) requires tracking temperatures in thermally sensitive instrument as well as cables.

For LOCA analysis, the Tagami heat transfer coefficient is used for the inside of the concrete cylindrical wall, dome, and the structural surfaces inside the containment. Heat loss to ambient from the outside of the concrete wall takes place through natural convection with a heat transfer coefficient of 1 Btu/F-ft2 hr to 125 F ambient. For MSLB analysis, the Uchida correlation is used.

Specifications of a high ambient temperature combined with a low heat transfer coefficient minimizes heat loss to ambient, especially in a LOCA, which is run until containment temperature drops to its initial value prior to the event. As a result of several condition reports, extensive analyses were performed in CA05892, Rev. 0000 to find the most conservative set of coating system (pain & primer) with respect to thickness and the type of coating material. For example, 81

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 while the thickness of the coating on a small portion of the containment shell was higher than 7 mils, the containment response analysis conservatively assumes a coating thickness of 18 mils for MSLB and 22 mils for LOCA over the entire 73,230 ft 2 of the shell. Regarding the coating type, CA05892, Rev. 0000 determined that Ameron66/Ameron-D6 system results in higher containment peak pressure and temperature than Carboline-890. Therefore, the containment response analysis conservatively assumes Ameron-66/Ameron-D6 system even though most of the containment shell is coated with Carboline-890. This assumption is retained for low sump water temperature case as sufficient conservative is already built into its input data.

Thermal Conductors Initial Temperature: With the exception of the outside reactor wall, all heat sinks are conservatively assumed to be at an initial temperature of 125 F. The temperature of the outside reactor wall is assumed to be at 150 F, due to its proximity to the RCS. For the low sump water temperature case a temperature of 90 F is used for all the heat conductors.

Contact Resistance. Presence of an air gap between the steel liner and the concrete shell prevents perfect contact and ,impedes the flow of heat due the low thermal conductivity of gases. However, the licensing basis of CCNPP does not require consideration of the thermal resistance due to the presence of an air gap. The justification for relaxation of this constraint is based on the expansion during the inside containment pressurization events. As such, this region is not included in modeling of the containment shell.

Heat Sink Dimension, Surface Area, and Material Properties: The physical properties of various heat sinks materials are presented in Table 4.5.6.

Containment Electrical Penetrations: Modeling of the containment electrical penetrations follows the same method used by Bechtel in COPATTA. Bechtel has modeled the Amphenol penetrations as a 1" thick slab where the insulated penetration is a 1" slab covered with 2" Epoxy insulator on one side and an adiabatic boundary' condition on the other. The Raychem termination to the penetration is modeled as a solid cylinder made of copper covered by Polyolefin insulation.

Properties used for various penetrations are shown in Table 4.5.7. In this table, three sets of data are shown for Polyolefin. Since Bechtel could not obtain exact thermal properties for Polyolefin, three sets of propertie's were used in COPATTA and the set resulting in the highest temperature profile was reported. Similar logic is used in GOTHIC.

Improvised heat sinks. In the 2002 refueling outage during which original steam generators were replaced, several heat sinks were removed from the containment. To make up for the removal of meals already credited in containment response, steel plates were constructed and the improvised passive heat sink were coated and placed in containment at 45' elevation to makeup the permanent of credited heat sinks.

Addition of Scaffolding. Outage management may leave a steel scaffolding in the containment on permanent basis. While this reduces the available volume for steam expansion, it also introduces a surface area to the containment for steam condensation. The net result is a reduction in peak vapor pressure and temperature. Therefore, for the high sump temperature

'I 82

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 case, it is conservative to ignore the presence of this additional heat sink. For the low sump water temperature case, an additional 10,000 ft2 steel is conservatively modeled. While no credit is taken for steam condensation on the scaffolding, no penalty was also taken for reduction in containment free volume for steam expansion. The discussion below is carried from the AOR.

To show the net is still conservative, a dummy heat conductor was added to both LOCA and MSLB models. A thickness of 0.5 in (twice the thickness of the scaffolding) was assumed. This yields a volume of 20,000 x (0.5/12) = 833.4 ft3 , deducted from 1,988,614 gives 1,987,780.6 ft3 .

The bare conductor was assumed to be stainless steel (low thermal conductivity) and coated with paint. Both LOCA and MSLB peak P&T dropped. For example, MSLB peak pressure dropped from 49.07 psia to 47.85 psia and temperature from 353.9 F to 351 F. Further, in another case, the penalty for volume deduction corresponds to 20,000 ft2 steel with 0.5" thickness. The credit taken was for a 10,000 ft2 stainless steel coated with 0.003" paint and 0.004" primer. Still, peak pressure and temperature dropped. The effect of potential scaffolding is ignored at this time. No change is introduced into the MSLB analysis and the results obtained in Rev. 0000 will remain valid for Rev. 0001. Only LOCA profiles change for time following RAS.

83

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.5.3-1. Comparison of Overall Heat Transfer Coefficients (Btuhr-ft2 -F)

Heat Exchanger SDC-< 10,000 s SDC > 10,000 s

• CCW < 10,000 s CCW > 10,000 s Ri (hj) 1.856E-3 (538.80) 2.077E-3 (481.39) 7.288E-4 (1372.12) 7.125E-4 (1403.41)

Ri (hi) 1.134E-3 (881.64) 1.145E-3 (872.79) 1.386E-3 (721.38) 1.321E-3 (756.92)

Rwaii 4.75E-4 4.75E-4 4.75E-4 4.75E-4 Rf.ol 0.00150 0.00150 0.00150 0.00150 ZR 4.965E-3 5.197E-3 4.089E-3 4.008E-3

,UAoR (note 1) 201.4 192.4 244 249.5 UCOPAWA 206 195 288 281 1: It is assumed that A,z A, and an average tube diameter of 0.70" is used Table 4.5.3-1. Comparison of Overall Heat Transfer Coefficients (Btuihr-ft2 -F)

Heat Exchanger SDC < 10,000 s SDC > 10,000 s CCW < 10,000 s CCW > 10,000 s Ri (hi) 1.856E-3 (538.80) 2.077E-3 (481.39) 7.288E-4 (1372.12) 7.125E-4 (1403.41)

Ri (hi) 1.134E-3 (881.64) 1.145E-3 (872.79) 1.386E-3 (721.38) 1.321E-3 (756.92)

Rwall 4.75E-4 4.75E-4 4.75E-4 4.75E-4 Rfo.I 0.00 0.00 0.00 0.00 ER 3.465E-3 3.697E-3 2.589E-3 2.508E-3 UAOR (note 1) 288 270 386 398 UCOPATJ4 206 195 288 281 Notes related to Tables 4.5.3-1 and 4.5.3-2.

The overall heat transfer coefficient is given by:

A1 +__ fj ln(do / di) 1 1-I UA=L.Lhi +Td-L 21rkL + f.L + rdoLho" Assuming Ai z Ae, introducing an average diameter for the tubes (w = (di + do)/2) and using the assumption and the average diameter in the above relation, the overall heat transfer coefficient is simplified to:

_______ od) 1fl~

Values in the above table are obtained by using a) tube gage 18 and tube diameter of 3/4 inch (di=

0.652 and do = 0.75") and stainless steel thermal conductivity of k = 8.6 Btu/hr-ft-F.

84

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.5.4 Description of Containment Heat Conductors (Passive Heat Sinks) Used in LOCA No Representing Area Paint Primei Steel Concrete Other

__ft_2 (in) (in) (in) (in) (in) 1 Shell (Wall & Dome) 73230 22E-3 3E-3 2.6E-1 42 -

2 Misc. Unlined Concrete 41900 - - - 18 -

3 Outside Reactor Cavity 6160 - - - 12 -

4 Galvanized Steel 95583 - 9.7E-2 - 3.4E-3 (nl) 5 Miscellaneous Steel 25383 6E-3 6E-3 1.37E 6 Miscellaneous Steel 17540 6E-3 6E-3 2.03E -

7 Miscellaneous Steel 13161 6E-3 6E-3 2.48E -

8 Miscellaneous Steel 7441.5 6E-3 6E-3 3.56E-1 - -

9 Miscellaneous Steel 3714 6E-3 6E-3 4.25E -

10 Miscellaneous Steel 9030 6E-3 6E-3 5.15E -

11 Miscellaneous Steel 2230 6E-3 6E-3 6.77E -

12 Miscellaneous Steel 5131 6E-3 6E-3 8.42E -

13 Miscellaneous Steel 4338 6E-3 6E-3 1 - -

I 14 Miscellaneous Steel 1915 6E-3 6E-3 2.412 -

15 Wall in Penetration Area 2470 6E-3 6E-3 7.5E-1 45 -

16 Liner Plate 7750 - 187E-1

.- (n2 17 Ctmt. Shield Barrier 203.3 - - 1.0 (n3) 18 Cavity Below El. 29' - 4" 1280 6E-3 6E-3 5E-1 12 1.0 (n4) 19 Reactor Cavity To El. 44' 968 6E-3 6E-3 2.5E-1 12 -

20 - Electrical Penetrations N/A N/A N/A N/A N/A N/A 29 (No. 20 through No. 29) 1 30 Improvised Heat Sinkt 10,000 N/A N/A 1.00 N/A N/A nl: Material is Zinc n2: Material is Stainless Steel n3: Material of the shield barrier is made entirely of lead n4: Material is air f Used in the minimum water temperature case To avoid modeling multiple heat sinks, Bechtel in the original COAPPAT code, lumped heat sinks by defining the following thickness groups. The same definition is adhered to in GOTHIC models.

Heat Sink Number Represents all steel having thickness (in) in the range of 5 0.12-0.15 6 0.18-0.24 7 0.24-0.30 8 - 0.30-0.40 9 0.40-0.50 10 0.50-0.625 11 0.625 - 0.75 12 0.75-1.00.

13 1.00-1.50 14 > 1.50 85

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.5.5. Description of Containment Heat Conductors (Pasive Heat Sinks) used in MSLB No Representing Area Paint Prime Steel Concrete Other

__() (in) (in) (in) (in) (in) 1 Shell (Wall & Dome) 73230 18E-3 3E-3 2.6E-1 42 -

2 Misc. Unlined Concrete 41900 - 18 -

3 Outside Reactor Cavity 6160 - 12 -

4 Galvanized Steel 95583 - 9.7E-2 - 3.4E-3 (n])

5 Miscellaneous Steel 25383 6E-3 6E-3 1.37E-1 -

6 Miscellaneous Steel 17540 6E-3 6E-3 2.03E-1 -

7 Miscellaneous Steel 13161 6E-3 6E-3 2.48E-1 -

8 Miscellaneous Steel 7441.5 6E-3 6E-3 3.56E-1 -

9 Miscellaneous Steel 3714 6E-3 6E-3 4.25E-1 -

10 Miscellaneous Steel 9030 6E-3 6E-3 5.15E-1 -

11 Miscellaneous Steel 2230 6E-3 6E-3 6.77E-1 -

12 Miscellaneous Steel 5131 6E-3 6E-3 8.42E-1 -

13 Miscellaneous Steel 4358 6E-3 6E-3 1 -

14 Miscellaneous Steel 1915 6E-3 6E-3 2.412 -

15 Wall in Penetration Area 2470 6E-3 6E-3 7.5E-1 45 -

16 Liner Plate 7750 -- - 1.87E-1 (n2) 17 Ctmt. Shield Barrier 203.3 -- - 1.0 (n3) 18 Cavity Below El. 29' - 4" 1280 6E-3 6E-3 5E-1 12 1.0 (n4) 19 Reactor Cavity To El. 44' 968.8 6E-3 6E-3 2.5E-1 12 -

20 (n5) Sump strainer 1 307.9 0.157 (n2) 21 (n5) Sump strainer 2 116.5 0.236 (n2) 22 (n5) Sump strainer 3 2670.5 1 0.049 (n2) n I:Material is Zinc n2: Material is Stainless Steel n3: Material of the shield barrier is made entirely of lead n4: Material is air n5: Correspond to GOTHIC conductors 30, 31, and 32 86

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.5.6. Material Physical Properties of Heat Conductors' Material Conductivity, k (Btu/ftrhr.F) Volumetric Heat Capacity, pc, (Btu/ft3.F)

Concrete 2.20 32.84 Carbon Steel 29.6 53.60 Stainless Steel 8.60 60.10 Paint (Ameron-66) 0.30 47.10 Primer (Ameron-D6) 1.01 21.70 Zinc 62.2 42.00 Lead 19.6 22.30 1: Properties are specified at 100 F.

Table 4.5.7. Material Physical Properties of Containment Penetrations Material Conductivity, k (Btulffthr-F) Volumetric Heat Capacity, pcx,(Btu/ft3 .F)

Copper 223 50.75 Epoxy-Glass 0.1089 26.97 Polyolefin (a) 0.189 54.90 Polyolefin (b) 0.194 28.70 Polyolefin (c) 0.031 13.10 (a), (b),'and (c) refer to three types of Polyolefin assumed in the analysis.

I 87

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.5.3 CONTAINMENT HEAT CONDUCTORS AFFECTED IN 2007 & 2008 RFOs The discussions in this sub-section is retained from the AOR in this calculation package.

Several modifications are performed in the 2007 & 2008 refueling outages, affecting containment passive heat sinks including the replacement of vessel head, installation of the containment sump passive strainer, and modifications in the Palfinger crane. These modifications are discussed in more details next.

Palfinger Crane Modifications: Changes in the Palfinger crane are specified in Reference Al and affect containment passive Heat Sinks numbers 10, 12, 13, and 14 as summarized below.

Volume of the added passive heat sinks are conservatively calculated based on the upper range of the metal thickness.

Heat Sink No. Thickness (in) Surface area (ft2) Volume (ft3) 10 0.50-0.625 11.00 0.573 12 0.75-1.00 161.0 13.42 13 1.00-1.50 50.00 6.250 14 1.5 154.0 19.25 Total: 40.00 Subsequent changes to the passive heat sinks surface areas results in the updated values as shown below:

Heat Sink No. Present value (ft2 ) Added area (ft2) New Value (ft2) 10 9019 11.00 9030 12 4970 161.0 5131 13 4308 50.00 4358 14 1761 154.0 1915 Carbon Steel Removal from Pressurizer Doghouse Platform: As specified in Reference A3, a total of 618 lb of carbon steel will be permanently removed from the Pressurizer doghouse platform. Since it is not clear if this material had been originally credited as a heat sink or not, in this calculation, it is conservatively assumed that the steel had been credited. Therefore, the following change were made to the surface areas of heat conductors 6, 7, and 8:

Conductor No. Thickness (in) Surface Area (f) Removal (ft) Revised Area (ft) 6 0.1875 18025 484.8 17540 7 0.2500 13172 11.33 13161 8 0.3750 7449.0 7.500 7441.5 88

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 The effect of the removal of 618 lbs of steal on the containment free volume for steam expansion is to increase the volume by about 1 ft 3 , as shown below:

3 V = m/p= 618/500 - 1 ft where in the above calculation, a density of 500 lbm/ft3 is assumed for carbon steel and the answer for volume is conservatively rounded down. However, the actual free volume calculated from surface areas and thickness is larger by 7 ft3 . Using smaller value for the containment free volume is more conservative.

Sump passive strainer: Installation of sump passive strainer adds additional passive heat sinks to the containment. Details of the heat conductors are specified in Reference A2 and summarized below.

Elevation (in) Thickness (in) Surface area (fte) Value of H (in) Volume (ft3 )

3-35 0.157 0.874(H - 3) 3 < H < 35 0.366 36 0.157 307.9 4.030 3-30 0.236 14.961(H - 3) 3 < H5 <30 7.944 30-34 0.236 29.877(H - 30) 30 < H < 34 2.350 36 0.236 116.5 2.291 6.590 0.049 381.5 - 1.558 10.18 0.049 381.5 - 1.558 13.77 0.049 381.5 - 1.558 17.36 0.049 381.5 - 1.558 20.95 0.049 381.5 - 1.558 24.54 0.049 381.5 - 1.558 28.13 0.049 381.5 - 1.558 31.72 0.049 381.5 - 1.558 35.31 0.049 381.5 - 1.558 Total Volume (ft3 ): 31.00 Since various thicknesses, specified for the sump passive strainer, do not match any of the existing heat conductors in UFSAR Table 14.20-5, three new passive heat sinks all made of stainless steel will be added to the above table and constructed in the related GOTHIC model.

Inclusion of the sump strainer as a heat sink is not as straight forward as the Palfinger crane, for example. The reason is that the strainer is located on the basemat. If fully covered by water during a LOCA, it cannot be credited for condensation of steam in the containment atmosphere. If partially covered, during the early stage of a LOCA, the exposed surface area is changing with time as water level rises. While these aspects can be considered in GOTHIC by using the SPLIT 89

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 option, a conservative approach is used in this calculation. In this approach the surface area of the strainer is treated based on the type of DBA.

In a MSLB, most of the area of the strainer is credited whereas in a LOCA no credit is taken for the Strainer metal. The reason is that in a LOCA the strainer is flooded in about 15 minutes.

Although the peak pressure and temperature occur in about 3 minutes, it is conservatively assumed that the whole strainer is flooded during the first 3 minutes. In contrast, water level raises to only about 6 inches during the entire 500 seconds that the event is analyzed. In a MSLB, peak temperature is reached in about one minute and the peak pressure in about four minutes. By the time the pressure has peaked, water level has barely reached 2.5 inches. Water level in the pool, in the case of a MSLB, is primarily due to the spray taking suction from the RWT and accumulating in the containment sump.

This discussion is used to obtain the surface area of the three new passive heat sinks.

Elevation (in) Thickness (in) Surface area ft) Value of H (in) Credited Area (ft 2) 6-35 0.157 0.874(H - 6) 6<H<35 25.35 36 0.157 307.9 - 307.9 Total Area (ft 2 ): 333.25 6-30 0.236 14.961(H- 6) 6<H<30 359.1 30-34 0.236 29.877 (H - 30) 30 < H < 34 119.5 36 0.236 116.5 - 116.5 Total Area (ft2): 595.1 6.590 0.049 381.5 - 381.5 10.18 0.049 381.5 - 381.5 13.77 0.049 381.5 - 381.5 17.36 0.049 381.5 - 381.5 20.95 0.049 381.5 - 381.5 24.54 0.049 381.5 - 381.5 28.13 0.049 381.5 - 381.5 31.72 0.049 381.5 - 381.5 35.31 0.049 381.5 - 381.5 Total Area (ft 2): 3,433.5 90

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Addition of Scaffolding. Outage management may leave a galvanized or aluminum scaffolding in the containment on permanent basis. While this reduces the available volume for steam expansion, it also introduces a surface area (on the order of 10,000 ft 2) to the containment. The net result is a reduction in peak vapor pressure and temperature. No credit is taken for the presence of scaffolding at this time. Detailed discussion is sub-section 4.5.1.

Vessel Head Replacement: Unit 1 vessel head was replaced in 2006 RFO. The related changes to the containment heat sinks were implemented in CCN CA05892-0005. Unit 2 vessel head has identical heat sinks as Unit 1 (per ES200500079, MS047). Therefore, to prevent having two sets of input data"for Units 1 and 2, a conservative set of data was chosen in the above CCN so that the input file applies to both units. Therefore, no further changes, with respect to the vessel head replacement will be needed.

It should be emphasized that heat conductor surface areas neglected in CCN CA05892-0005 will also remain conservatively ignored in this calculation while penalty for volume reduction of the related metals have been taken.

Effect on Containment Free Volume: The original: containment volume of V = 1,988,684 ft3 is adversely affected by 40 ft3 change in the Palfinger crane and 31 ft3 by the addition of the passive strainer. On the other hand, the removal of the platform adds 1 ft3 . Therefore, the total volume to be deducted from the containment free volume is 70 ft3 and the revised free volume becomes:

3 V = 1,988,684 - 70 = 1,988,614 ft The actual free volume calculated from surface areas and thickness of the PZR doghouse platform is larger by 7 ft3 . Using smaller containment volume for vapor expansion is more conservative.

<2 Additional Heat Conductor forLow Sump Water Temperature Case. For the low sump water temperature case, a bare 10,000 ft2 bare stainless steel coated carbon steel of one inch thickness is credited in the calculation, even though in reality such heat conductor has not been placed in the containment. The credit acts as dual penalty by allowing increased condensation but not reducing the containment volume (by 10,000 x 1/12 = 833.3 ft3).

91

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.6. MASS AND ENERGY RELEASE RATES FOR LOCA This includes information regarding the rate of mass and energy transfer from the RCS pipe break to the containment atmosphere (steam flow rate), as well as to the containment sump (the spillage flow rate). It also includes information regarding some safety injection (SI) water spillage to the sump, SIT nitrogen transfer to containment atmosphere for cold leg LOCAs (cx and ci), and SIT spillage in the case of cold leg LOCA from the broken leg. The SIT nitrogen flow rate, as calculated by ABBCE/WEC, is shown in Table 4.5, which is the same as the AOR since the fine print and maximum rate of safety injection have nothing to do with the rate of nitrogen release subsequent to SIT injection. The short term M&E (up to RAS) is produced by ABBCE/WEC, as shown in Reference 2, included in this calculation. Thereafter,' the mass and energy transfer rates for long term are produced by GOTHIC RCS model.

4.6.1 SHORT TERM M&E FOR VARIOUS LOCA CASES The short term M&E includes the mass and energy release rates during the blowdown, refill, and reflood phases. ABBCE/WEC refers to these as blowdown, reflood, and post reflood phases. The blowdown phase is very short and for large breaks ends at about 15 seconds. Mass flow are in the early stage of blow down is very high (in excess of 300 Mlbmihr). For large breaks, the M&E of the blow down phase is generally independent of the number of available safety injection pumps.

This is because, RCS pressure is high in the early stage of the blow down, the blow down duration is very short, and associated delay of safety injection precludes any significant flow into the RCS.

Therefore, the M&E of the blow down phase applies to all cases of ci and cx as well as AOR (minimum SI flow rate) and WEC (maximum SI flow rate). The difference becomes evident in the reflood and post-reflood phases.

The major difference between cold leg and hot leg LOCA is the fact that safety injection in a hot leg LOCA bypasses the steam generators and leaves vessel through the broken hot leg (regardless of whether injected into the broken or unbroken loop). Therefore, there are no reflood and post reflood phases in a hot leg LOCA. The flow enthalpy of a hot leg LOCA during blow down is also higher than that of the cold leg since the stream is first heated in the core before entering hot leg.

Upon pipe break when vessel inventory flows into the containment, steam tends to flow upward and water downward. Since the RCS and containment are decoupled in containment analysis, the flow rates through the break are traditionally segmented,(as discussed in Section 4.4) into break flow rate, spillage flow rate, SIT flow rate, and condensate flow rate. Since GOTHIC does not add the water stream directly to the sump and instead allows the possibility of some water acting as spray in the vapor region, the cold condensate and SIT water are directly added to the sump.

The key milestones of both hot leg and cold leg LOCA taken from Reference 2 are shown in Table 4.6.1. Note that time to RAS as used in the GOTHIC model for the 2 EDG cases (cx and hhx) is 1800 seconds and differs from those calculated in Reference 2. This is because, Reference 2 uses the values credited for containment spray and the safety injection flow rates to calculation actual time to RAS whereas the 1800 seconds represents a conservatively short time to realign the suction to the sump, avoiding vortex in RWT (IRE-021-644). Values used in GOTHIC are in Table 4.6.2.

92

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 /

M. Massoud ECP-11-001022 August 2012 Table 4.6.1. Key Points in Time (all in seconds) For Various LOCA Cases (per Reference 2)

Case End of Blowdown End of Reflood End of post reflood Time to RAS

_(EBD) (ERF) (EPR), (RAS) cx 14.3 159.50 225.21 1955.79 ci 14.3 194.70 279.41 3029.81 hhx 11.2 - 1947.22 hhi 11.2 3019.68 hi 58.0 3049.44 Table 4.6.2. Key Points in Time (all in seconds) For Various LOCA Cases (as Used in GOTHIC)

Case End of Blowdown End of Reflood End of post reflood Time to RAS

._ (EBD) (ERF)* (EPR) (RAS) cx 14.3 159.50 225.21 1800 ci 14.3 194.70 279.41 3029.81 hhx 11.2 1800 hhi 11.2 3019.68 hi 58.0 3049.44 93

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.6.2 LONG TERM M&E FOR VARIOUS LOCA CASES To produce identical results as Bechtel's NRC approved method, it was essential that the RCS model in GOTHIC to be based on assumptions consistent with those used in COPATTA. The Bechtel data was based on a simplistic mass and energy balance in the vessel. There is continuous equilibrium of the liquid and vapor phases, and there is no flow resistance between the vessel and the containment. These conditions could not be ýcompletely imposed in GOTHIC although they have been approached by appropriate definition of the input data. The large break area and small loss coefficient minimize the fluid resistance of the break flow path. The lumped parameter volume for the vessel and the large pool area impose equilibrium between vapor and liquid.

RCS: An additional lumped volume is included to the GOTHIC model of CCNPP to model the reactor vessel for cx, ci, hi, hhi, and hhx.

Volume: The RCS volume below the pipe rupture is 3210 ft3 . Since COPATTA uses a lumped model, this volume represents the fluid volume during the entire LOCA event. In GOTHIC, a slightly larger volume is used (3220 ft3) to allow for vapor accumulation. The initial water inventory is identical to that used in COPATTA calculation, as the initial volume fraction of water is specified as the ratio of the COPATTA volume of 3210 ft3 divided by the RCS volume.

Rate of Core Decay Heat: The decay power is based on the NRC's Branch Technical Position ASB 9-2 as shown in Table 4.4. This is consistent with the Bechtel's methodology. The low sump water temperature case uses ORIGEN model, which predicts the lowest decay heat rate.

Rate of RCS Sensible Heat: In a LOCA, the rate of heat addition to the break flow due to the RCS sensible heat is integrated in the rate of decay heat. The RCS sensible heat is produced by the ABBCE/WEC. This accounts for the stored energy in the steam generator tubes, and the rest of the RCS metals (such as cold and hot leg piping as well as the reactor vessel shell and internals).

The sensible heat is then added to the decay heat and provided to the CCNPP GOTHIC model in a forcing function. Table 4.7 shows the effect of addition of RCS sensible heat to the decay heat.

The decay and sensible heat rates are modeled as a GOTHIC heater depositing energy in the core.

Figure 4.6.1 shows the comparison between decay heat models and with decay plus sensible heats.

Table 4.7. Sample Decay & Sensible Heats Rates versus Time after Shutdown (cx)

Time (s) Decay Power (Btu/sec) Decay + Sensible Heat (Btu/sec) 331 8.29E+04 1.21E+05 344 8.20E+04 1.20E+05 357 8.13E+04 1.19E+05 371 8.05E+04 1.18E+05 RCS Pool Area: An artificially large surface area of 10,000 ft2 is allocated to the pool area of the RCS volume to ensure thermal equilibrium between the water and the steam phase. This conforms with the lumped model used in COPATTA.

94

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1.E+05 I.E+05

%A i*.E+05 --

8.E+04 1

0 O%

.4-C

.0 GA 4.E+04 62.E+04 0.E00 2.E+02 2.E+03 2.E+04 2.E+05 2.E+06 2.E+07 Time (sec)

Figure 4.6.1. Comparison between the decay heats and the decay plus sensible heats (Sensible heat represents the WECcx case)

Pipe Break Parameters: The break between the RCS and containment is represented by a GOTHIC flow path. The flow path elevation and height are consistent with the CCNPP design values of 36.08 ft and 2.5 ft, respectively. While these values are applicable to a cold leg LOCA, they are also used in a hot leg LOCA as their effect on the results is negligible (P.E. << enthalpy).

Initial RCS Temperature & Pressure: RCS is initially saturated at the pressure and temperature corresponding to the containment temperature and total pressure at the time that blow down in the case of a hot leg LOCA and the post-reflood phase in the case of a cold leg LOCA are terminated.

SIT Nitrogen: It is conservatively assumed that in a cold leg LOCA, all of the nitrogen inventory of the safety injection tanks (SITs) enters the containment following the SIT discharge, resulting in further pressurization of containment. The nitrogen flow rate is calculated by ABB-CE/WEC and used in GOTHIC as a forcing function. In cx, this is modeled by boundary condition 5F (Sec. 4.4).

The nitrogen mass flow rate versus time is summarized in Table 4.8.

95

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.8. Mass Flow Rate of SIT Nitrogen to Containment in a CL-LOCA Time -Mass FlowRate

-(s) ' (Ibm/sem) 0.00 0.00 65.80 282.97 66.30 204.02 66.80 185.97 67.30 168.31 67.80 151.01 68.30 134.00 68.80 117.21 69.30 100.54 69.80 83.89 70.30 67.04 70.80 49.59 71.30 26.52 71.80 0.00 96

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.6.3 FLOW RATES OF VARIOUS LOCA BOUNDARY CONDITIONS Various flow rates and associated enthalpies 'are shown in Table 4.9. This table shows values and the related period of application as suggested in Reference 2. Table 4.10 shows similar values but the period of application commensurate with the early termination of LPSI.

Table 4.9. SI and Spillage to RCS & Sump Per Reference 2 SI to Sump SI to RCS SI to RCS SIT Spillage EBD - RAS EPR - RAS Post-RAS A period of 30 seconds CASE rh (lbm/s) T (F) mh (lbm/s) T (F) th lbm/s) T (F) 7t (lbm/s) h (Btu/Ibm) cx 270 100 824 100 100.44 T sump 2359 88.67 ci 205.62 100 550 100 57.76 Tsump 2359 88.67 EBD - RAS EBD - RAS Post-RAS A period of 30 seconds hhx 0.00 100 1206.42 100 204.71 T sump NA NA hhi 0.00 100 822.49 100 110.09 T sump NA NA hi 0.00 100 822.49 100 110.09 T.sump NA NA Table 4.10. SI and Spillage to RCS & Sump For Early Termination of LPSI SI to Sump SI to RCS SI to RCS SIT Spillage EBD - RAS EPR - ETL Post-ETL A period of 30 seconds CASE mh (Ibm/s) T (F) rJh (lbm/s) T (F) 712(lbm/s) T (F) ?h (lbmns) h (Btu/lbm) cx 301.6 100 904.81 100 153.53 T sump 2359 .88.67 ci 195.62 100 616.87 100 82.57 T _sump 2359 88.67 EBD - RAS EBD - ETL Post-ETL A period of 30 seconds hhx 0.00 100 1206.42 100 204.71 T sump NA NA hhi 0.00 100 822.49 100 110.09 T sump NA NA hi 0.00 100 822.49 100 110.09 T sump NA NA Several values for early termination of LPSI (ETL) were tried. Currently, the Early termination of LPSI is ETL = 1200 seconds into the LOCA. The SI flow rate of Reference 1 (AOR) and for ETL are depicted in Figure 4.6.2.

Comparisons of AOR with WEC flow rates for cx and hi cases are shown in Figures 4.6.3 through 4.6.6. Graphs of flow rate and specific enthalpy for all other AOR LOCA cases are retained from the calculation of record as shown in Figures 4.6.7 through 4.6.12.

Since the reduction in SI flow rate (after 1200 seconds) was considered after providing SI data to Westinghouse, the time to RAS calculated in Reference 2 are shorter than actual. However, this is conservatively ignored in this calculation and Reference 2 values for time to RAS are used (that is except for the 2-containment spray cases where the shortest time to RAS of 1800 seconds is used).

97

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 SI Flow Rate EBD RAS Time SI Flow Rate RWT S ~Sump EBD ETL RAS Time Figure 4.6.2. Depiction of SI flow to RCS for AOR (top) and this calculation (bottom)

EBD: The value for the end of blowdown (EBD) phase depends on the type of LOCA ETL: The value for early termination of LPSI (ETL) is 1200 seconds RAS: The value for the recirculation actuation signal depends on the type of LOCA 98

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.6.4 KEY M&E RELATED DATA The key data pertinent to the use of M&E are shown in Tables 4.10.1. In this table, the column under vendor represents the duration for which the vendor-produced M&E is used and the column under GOTHIC shows the duration where M&E is produced by GOTHIC. The switch over time is the time at which the blowdown phase for hot leg LOCA cases and the reflood phase for cold leg LOCA cases are concluded. Data under the WEC comments are takenfrom Reference 2.

Table 4.10.1. M&E Duration of Applicability and the time of switch over LOCA AOR WEC Vendor GOTHIC Vendor GOTHIC cx 0.00 - 222.30 > 222.30 0.00 - 225.21 > 225.21 ci 0.00 - 280.90 > 280.90 0.00 - 279.41 > 279.41 hi 0.00-51.50 > 51.500 0.00 - 58.003 > 58.003 hhx NA NA 0.00 - 11.201 > 11.201 hhi NA NA 0.00 - 11.201 > 11.201 The RCS pressure and tem\perature at the time of switch over are shown in Table 4.10.2. Data under the WEC comments are taken from Reference 2.

Table 4.10.2. RCS Pressure and Temperature at the time of switch over LOCA AOR WEC Pressure (psia) Temperature (F) Pressure (psia) Temperature (F) cx 64.00 296.95 62.97 295.86 ci 64.00 296.95 63.04 295.93 hi 61.50 294.33 61.76 294.58 hhx NA NA 58.17 290.67 hhi NA NA 58.17 290.67 Finally, the time to RAS for various LOCA cases are shown in Table 4.10.3. For those LOCA cases in which two containment sprays are credited, the time to RAS per Mechanical Engineering is conservatively reduced to 1800 seconds for prevention of vortex in the RWT. Data under the WEC comments are taken from Reference 2.

Table 4.10.3. Time to RAS (sec)

LOCA AOR WEC cx 1800.00 1800.00f ci 4174.78 3029,81 hi 4180.89 3049.44 hhx NA 1800t hhi NA 3019.68 According to Reference 2 these are 1955.79 and 1947.22 sec, respectively 99

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1000000 100000 10000 1000 .

100 1.10.100 1000 100 0.1 11t 100 1000 Figure 4.6.3. Short term mass flow rate (lbm/s) versus Time (s) for LOCA (AOR cx) 1000000 100000 - iii_____

4A E

1.0000 Wi o 1000 ------- , .... -

M 3ý 1000 10 0.01 0.1 1 10 100 1000 lime (sec)

Figure 4.6.4. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (WEC cx) 100

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0

0 10 20 30 40 50 60 Figure 4.6.5. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (AOR hi) 0 2 4 6 8 10 12

.E+04 - T 1.OE+05

-WE~h 9.OE+04

.E+04 - - WEC.hi

% -.,-'...,WEC-hhx 9.OE+04 2.E+04 7.OE+04 6.OE+04 2.E+04 --- 5.0E+04 4.OE+04 l.E+04 -

.OE+04

__* ._*2.0E+04 W' 1.OE+04 O.E+00 - ' O.OE+00 0 10 20 0 40 50 60 70 Figure 4.6.6. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (WEC hi and WEC-hhx))

101

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR.

CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 1000000 100000 10000.

1000 m 100 1 10~ ~

0.1 1 10 100 1000 Figure 4.6.7. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (AOR cx)

(Same as Figure 4.6.1) 1400 rmm m n 0 50 100 150 200 250 Figure 4.6.8. Short term enthalpy of flow at the break (Btu/lbm) versus Time (s) for LOCA (AOR cx) 102

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 120000 100000 80000 60000 40000 20000 0

0.1 1 10 100 1000 Figure 4.6.9. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (AOR ci) 1400 1200 1000 800 600 400 200 0

0 100 200 300 400 500 600 700 800 900 1000 Figure 4.6.10. Short term enthalpy of flow at the break (Btu/lbm) versus Time (s) for LOCA (AOR ci) 103

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0

0 10 20 30 40 50 60 Figure 4.6.11. Short term mass flow rate (Ibm/s) versus Time (s) for LOCA (AOR hi)

Figure 4.6.12. Short term enthalpy of flow at the break (Btu/lbm) versus Time (s) for LOCA (AOR hi) 104

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.7. MASS AND ENERGY RELEASE RATES FOR MSLB The discussion in this sub-section is retained from the AOR For MSLB from Reference 2.

The mass and energy transfer data as used-in a MSLB analysis (sl input file) are produced by FTI (Steam Line Break For Containment," 32-5004396, Rev. 04, CCNPP Calculation CA05684, Rev

0. February 2001) as presented in Tables G.1 (Reference 2). FTI used the RELAP and the CONTEMPT codes to perform a parametric study on reactor power level to determine the most limiting break mass flow rate and enthalpy. It turned out that for peak pressure and temperature (s0), the most limiting mass and energy transfer rates occur at 75%,power level.

Key MSLB data are also shown in (Reference 2) Table 4.10.

4.8. 10CFR50.49 ENVIRONMENTAL QUALIFICATION (EQ)

The effect of harsh environmental conditions on equipment during a DBA is generally analyzed by using the guidelines provided in NUREG-0588. These guidelines for example allows for up to 8%

revaporization of the condensate if the steam in the containment is superheated. Steam superheat generally occurs in the containment in the case of a MSLB. On the other hand, to maximize the rate of heat transfer to equipment, the guidelines require the heat transfer coefficient calculated by the Uchida correlation to be increased by a factor of 4.

The EQ evaluations at CCNPP are based on the detailed discussion provided in Appendix A of this calculation package (Reference 2), which is the same as Appendix E of FTI calculation 32-5013085, "Steam Line Break Containment, Response for Equipment Qualification," CA05867, Rev.0000.

105

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 6000 -m-mi ~ i r n n n i 5000 = = -- ----------------- 1-4000 3000  :: i i i i i i 2000 == - -- L---- L--- --------

10001 0100 200 300 400 500 Figure 4.7.1. Mass flow rate (Ibm/s) versus Time (s) for MSLB case (75% Power Level) 1250 1240 1230 -

1220 -

1210-1200 1190-1180-1170 1160 1150 -

1140 0 100 200 - 300 400 500 Figure 4.7.2. Break Enthalpy (Btu/lbm) versus Time (s) for MSLB case (75% Power Level) 106

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 8000.00 7000.00 6000.00 5000.00 4000.00 3000.00 2000.00 1000.00 0.00 100 200 300 400 500 Figure 4.7.3. Mass flow rate (Ibm/s) versus Time (s) for MSLB (50% Power Level) 1250.00 1240.00 QKS-;It A I I.f~IV.:~tI 1230.00 1220.00 1210.00 4,7 4-1200.00

~~77; 1190.00 1180.00 1170.00 1160.00 1150.00 1140.00 0 100 200 300 400 500 Figure 4.7.4. Break Enthalpy (Btu/lbm) versus Time (s) for MSLB (50% Power Level) 107

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.9.

SUMMARY

OF INPUT DATA Key input data for hot sump water temperature case are summarized in Table 4.11 and for low sump water temperature case in Table 4.12. Key differences between input data of LOCA and MSLB are summarized in Table 4.13.

Table 4.11. Data Independent of the type of DBA, to Maximize Sumi Water Temperature Parameter Value Containment volume (ft3 ) 1,988,614 Initial pressure (psia) 16.50 Initial temperature (F) 125.00 Initial relative humidity 20%

Pressure to activate spray (psia) 19.45 Pressure to activate air coolers (psia) 19.45 Flow rate of one spray (GPM) 1250 Temperature of pre-RAS spray (F) 100 Pre-RAS heat transfer of one fouled air cooler (Btu/hr) Per Table 4.5.1 Post-RAS heat transfer of one fouled air cooler (Btulhr) Per Table 4.5.1 Spray efficiency' Per Table 4.5.3 Heat transfer area of one SDC-HX (ft2 ) 4990 Flow rate per one DSC-HX (lbm/hr) 8.9596E5 SDC-HX tube/Shell Heat transfer coefficient < 10,000 s (Btu/hr-ft-F) 538.80 & 881.64 SDC-HX tube/Shell Heat transfer coefficient > 10,000 s (Btu/hr-ft2-F) 481.39 & 872.79 CCW-HX tube/Shell Heat transfer coefficient < 10,000 s (Btu/hr-ft2 -F) 1372.12 & 721.38 CCW-HX Tube/Shell Heat transfer coefficient > 10,000 s (Btu/hr-ft 2-F) 1403.41 & 758.92 Flow rate of one CCW-HX (lbm/hr) 2.74E6 Bay Water Temperature (F) 90 Fouling factor primary & Secondary sides (hrft2 -F/Btu) 5e-4 & 0.00105 Thermal conductor data Tables 4.3.1, 2, Ambient temperature (F) 125 Heat transfer coefficient with ambient (Btu/hr-ft2 -F) 1 Note the related discussion in the text 108

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 Table 4.12. Data For Low Sump Water Temperature Case Parameter Value Containment volume (ftI) 1,988,614 Initial pressure (psia) 14.7 Initial temperature (F) 120.00t Initial relative humidity 100%

Pressure to activate spray (psia) 19.45 Pressure to activate air coolers (psia) 19.45 Flow rate of one spray, pre-RAS (GPM) 1350 Flow rate of one spray, post-RAS (GPM) 1800 Temperature of pre-RAS spray (F) 40 Pre-RAS heat transfer of one fouled air cooler (Btu/hr) Per Table 4.5.2 Post-RAS heat transfer of one fouled air cooler (Btu/hr) Per Table 4.5.2 Spray efficiency" Per Table 4.5.3 Heat transfer area of one SDC-HX (ft) 4990 Flow rate per one DSC-HX (lbm/hr) 8.9596E5 SDC-HX tube/Shell Heat transfer coefficient < 10,000 s (Btu/hr-ft2-F) 538.80 & 881.64 SDC-HX tube/Shell Heat transfer coefficient > 10,000 s (Btu/hr-ft2 -F) 481.39 & 872.79 CCW-HX tube/Shell Heat transfer coefficient < 10,000 s (Btu/hr-ft2 -F) 1372.12 & 721.38 CCW-HX Tube/Shell Heat transfer coefficient > 10,000 s (Btu/hr-ft 2 -F) 1403.41 & 758.92 Flow rate of one CCW-HX (lbm/hr) 2.74E6 Bay Water Temperature (F) 40 Fouling factor primary & Secondary sides (hrft2-F/Btu) 0.00 & 0.00 Thermal conductor data Tables 4.3.1, 2, Ambient temperature (F) 10 Heat transfer coefficient with ambient (Btu/hr-ft2-F) 1

• Note the related discussion in the text t Another cases using an initial temperature of 90 F was also analyzed 109

CONTAINMENT RESPONSE ANALYSI *SIN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012_

Table 4.13. Inputs & Assumptions For LOCA (cx) versus MSLB (sl)

Category Parameter LOCA MSLB Mass & Energy Break Flow Rate (lbm/s) Reference 2 Figure 4.7.1 - 4.7.3 Release Break Enthalpy (Btu/s) Reference 2 Figure 4.7.2 - 4.7.4 Rates Nitrogen Flow Rate (Ibm/s) Table 4.5 NA Containment No. of Sprays 2 2 Spray Delay for Actuation (s) 70.9 62.9 Data Flow Rate (Ibm/s), 344.5 344.5 Containment No. of CACs 2 4 Air Cooler (CAC) Delay for Actuation (s) 35.9 10.9 Safety Flow Rate, Pre-RAS (Ibm/s) 904.8 NA Injection Flow Rate, Post-RAS (Ibm/s) 153.5 NA RAS Long Term Cooling Initiation (s) 225.2 NA Time of RAS (s) 1800 NA Design Basis Event Initiating Event CL Break SL Break Single Failure Loss of 1 SRW SGFP fails to trip Concurrent Failure LOOP None t Break Size (ft2) 9.82 1.9

• These refer to the Appendices of CA05892, Rev. 0000 110

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 4.10 CHANGES MADE TO THE AOR INPUT DATA To summarize, since this calculation is based on the AOR, it uses all of the inputs and assumptions used as used in the AOR except for the data related to M&E and those used in the low sump water temperature case. For example, in the high sump water temperature cases, the following data are identical with the data used in AOR:

- Initial conditions

- Volume data for containment and reactor vessel

- Heat conductors

- Flow path

- Components

" Valves

" Heat exchangers

" Spray nozzle

• Air coolers

" Heaters The changes related to M&E are primarily made in:

- Boundary Conditions

- Forcing Functions

- Trips These changes appear in the related forcing functions for break mass flow rate, break enthalpy, and decay and sensible heat (DEC_SEN). The key flow rates and key times are summarized in Tables 4.9, 4.10, 4.10.1, 4.10.2, and 4.10.3.

IlI

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX E AMBIENT ENVIRONMENTAL SERVICE CONDITIONS, ES-014 (See Latest Revision ES-014 Section 5.5) 112

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 ES-0 14 Summary of Ambient Environmental Service Conditions Revision 4 Page 38 of 114 5.5 Programmatic Environmental Service Conditions (Continued)

Use of UFSAR, Chapter 14 analysis for the CCNPP EQ program was reconfirmed by Nuclear Regulatory Matters (Reference 135).

I) Loss of Coolant Accident (LOCA) Event BGE Calculation CA05892, (Reference 132) provides the bounding containment temperature profile information.

For Environmental Qualification (EQ)of I0CFR50.49, Electrical Equipment, the enveloping LOCA temperature profile is derived by utilizing the steam iaturation temperature corresponding to the peak accident pressure profile for a postulated LOCA. This is an NRC Staff requirement which has been utilized for the I0CFR50.49 (EQ) Program in lieu of the actual containment LOCA peak temperature profile. TheNRC Staff requirement was specified to include margin to account for higher than average temperatures in the upper region of the containment that can exist due to stratification. This specific EQ requirement was specified in the NRC's Safety Evaluation for Environmental'Qualification of Safety Related Electrical Equipment Dated, May 28, 1981 for Docket No.: 50-317/318 (Reference 150).

Consistent with this NRC requirement, a bounding containment LOCA temperature profile was developed by BGE utilizing the design maximum containment pressure of 50 psig.as the peak pressure with a corresponding saturated steam temperature of 297'F. This bounding containment accident temperature profile was subnirted to the NRC on September I, 1981 (Reference 76) in response to the above discussed NRC Safety Evaluation Report.

The BGE interpretation, of this NRC requirement was that the use of steam saturation temperature at the peak accident pressure profile is only applicable for the initial peak pressure profile. As the accident progresses, the containment atmosphere has achieved a homogeneous quasi-equilibrium state where the air partial pressure has become a much larger fraction of the total pressure. After recirculation actuation (RAS), the actual containment temperature profile, for a postulated LOCA, is then utilized to complete the LOCA temperature profile for containment. This, interpretation is graphically represented in the above discussed BGE response to the NRC SER Dated, September 1, 198.1 (Reference 76). This BGE interpretation of the NRC requirement was internally reconfirmed as discussed in References .51. and 152.

An exception wastaken, by EGE, to ihis NRC requirement, in 198 1,to utilize steam saturation temperatures corresponding to peak pressures.

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At the time the NRC SER was issued, it was known that one type of equipment within the EQ Program was qualified to temperatures less than a peak temperature of 296OF'. In particular the peak temperature qualification was not demonstrated to 296 0 F for the Amphenol Electrical Penetration Assemblies (EQ File EPA004). The NRC recognized this potential and the SER specifically stated that" If there is any equipment that does not meet the staff position, the Licensee must provide either justification that the equipment will perform its intended function under the specified conditions or propose corrective actions." The applicable justifications for this equipment was made available to, and accepted by the NRC3 as documented in References 149 and 154.

The above NRC commitment was revised as part of the Steam Generator Replacement Project. A commitment change evaluation was performed. In Reference 203 the revised commitment is as follows:

Use of the steam saturation temperature corresponding to the total building pressure (partial pressure of steam plus partial pressure of air) versus time will provide an acceptable margin for either a postulated LOCA or MSLB, whichever is controlling, as to potential adverse environmental effects on equipment, with the following exceptions:

1. Use of the steam saturation temperature corresponding to the vapor (partial pressure of the steam only) versus tinte can be utilized, for evaluating short term (60-150 seconds) high temperature transient of an MSLB, when it can be demonstrated that the equipment will be covered by a condensate layer at a temperature corresponding to the saturation temperature of the vapor at the partial pressure of the vapor. It must also be shown that this condensate layer will remain on the equipment (i.e., not evaporate off) throughout the short-term high temperature MSLB transient (i.e., the time that the containment airspace temperature is above the temperature of the condensate layer on the equipment).

'The steam saturation temperature corresponding to a pressure of SO psig is 297V not 296"F as specified by the NRC in Reference 150 and submitted by RGE to NRC according to reference 76.

3 Subsequentlo the issuance of the NRC's SER, discussions between BGE and the NRC (Reference 155) indicated that justifications required by the SER should be available to the NRC audit team as part of theLicensee's EQ documentation. This EQ documentation would be reviewed by the NRC audit team, using the SER as guidance, to determine acceptability of anylall justifications.

114

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2. Use of the containment temperature versus time as provided in the UFSAR Chapter 14 analysis can be utilized when it can be shown that the equipment is not located in the upper regions (conservatively estimated to be above the mid-point (i.e., 100' elev.) of the containment), potentially subjected to higher than average (i.e., UFSAR analyzed) LOCA/MSLB temperatures.

The justification provided was that the specified equipment was not located in the upper regions of the containment where stratification of steam would take place. Therefore, the actual containment temperature profile with a maximum of 276 0F was utilized as the required environmental qualification profile in lieu of the NRC requlremei*t for this equipment.

Long term containment pressure/temperature responses were originally provided to BGE by Reference 74 and were incorporated as part of BGE's submittal to the NRC in Reference 76.

Due to plant changes and re-analysis, since this initial NRC submittal, the bounding containment temperature/pressure profiles have changed. The current profiles a'e identified in UFSAR, Section 14.20.

Consistent with UFSAR, Section 6.2, (Reference 6) the maximum post-accident operating time period is defined as one (I) year. Consistent with DOR guidelines (Reference 168),

Section 5.2. 1, post-LOCA temperature and pressure qualification for equipment lowted inside containment shall be demonstrated for the time required to return to the pre-acoident ambient temperature and pressure following a LOCA. A maximum time period of 30 days is established as.the duration for environmental qualification based upon the temperature and pressure profiles originally, submitted to the NRC (Reference 76). Post-LOCA radiation qualification for inside containment equipment shall be demonstrated for a maximum of 1 year.

115

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A conservative representation of LOCAIMSLB temperature, pressure and humidity inside containment is shown in tabular form below:

Temperature Pressure Humidity Description {0F) (psi2) (%) Duration Initial Condition 120 0 70 -

Rise Rate from Normal Service 177(AT) 50 (6P) 30 (A%) 40 sec Ist Plateau 297(*) 50 100 2.5 hrs 2nd Plateau 212 13 100 5.5 his 3d Plateau 200 13 100 16 hrs 4b Plateau 180 7 G00 3 days 5' Plateau 160 5 100 6 days 6' Plateau 140 2.5 100 2 days 7n Plateau 125 1.5 100 18 days 8' Plateau 120 1 100 --

This conservative temperature/pressure profile bounds the UFSAR, Section 14.20 profiles as shown in CA05892 (Ref. 132), therefore, use of these profiles for EQ is acceptable.

2) Main Steam Line Break (MSLB) Event BGE Calculation CA05992, (Reference 132) provides the bounding containment MSLB temperature profile information.

For Environmental Qualification (EQ) of 10CFR50.49, Electrical Equipment, the enveloping accident temperature profile is derived by utilizing the steam saturation temperature corresponding to the peak arcident pressure profile for a postulated MSLB.

This is an NRC Staff condition which has been utilized for the IOCFR50.49 (EQ) Program in lieu of the actual containment accident peak temperature profile. The NRC Staff condition was specified to include margin to account for higher than average temperatures in the upper region of the containment that can exist due to stratification. This specific EQ condition was specified in the NRC's Safety Evaluation for Environmental Qualification of Safety Related Electrical Equipment Dated May

'28, 1981 for DocketNo.: 50-317/318 (Reference 150).

• The peak containment atmosphere temperature, due-to an MSLB, is 359°F7, however, presently installed in containment equipment exposed to the MSLB will only be exposed to MSLB saturation temperature (TSAT) at steam partial pressure. CA05892 (Reference 132) provides a detailed analysis. Therefore, this LOCA/MSLB temperature profile envelopes the MSLB TsAr temperature profile. For new equipment installation 3590 F/50 psig for 5 minutes should be specified as the I" plateau (above) with the above plateaus 1-8 renumbered as Plateaus 2-9.

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CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012

~ES-014 Revision 4 Summary of Ambient Environmental Service Conditions Page 42 of 114 5.5 Programmatic Environmental Service Conditions (Continued)

Consistent with this NRC condition, a bounding containment accident temperature profile was developed by BWE utilizing the design maximum containment pressure of 50 psig as the peak pressure with a corresponding saturated steam temperature of 297"F. This'bounding containment accident temperature profile was submitted to the NRC on September 1, 1981 (Reference 76) in response to the above discussed NRC Safety Evaluation Report.

The BGE interpretation of the NRC condition was that the use of steam saturation temperatures at the peak accident pressure profile is only applicable for the initial peak pressure profile. As the accident progresses, after the initial blow down, the containment atmosphere has achieved a homogeneous quasi-equilibrium state. where the air partial pressure has become a much larger fraction of the total pressure. At this point, the actual containment temperature profile, for a postulated MSLB, is then utilized to complete the accident temperature profile for containment. This interpretation is graphically represented in the above discussed BGE response to the NRC SER Dated September 1, 1981 (Reference 76). This BGE interpretation of the NRC requirement was reconfirmed according to References 151 and 152.

An exception was taken, by BGE, to this NRC condition to utilize steam.saturation temperatures corresponding to peak pressures.

At the time the NRC SER was issued, it was known that one type of equipment within the EQ Program that was qualified to temperatures less than a peak temperature of 297F. In particular the peak temperature qualification was not demonstrated to 2970F for the Amphenol Electrical Penetration Assemblies (EQ File EPA004). The NRC recognized this potential and the SER specifically stated that "If there is any equipment that does not meet the staff position, the Licensee must provide either justification that the equipment will perform its intended function under the specified conditions or propose corrective actions." The applicable justifications for this equipment was made available to, and accepted by the NRC as documented in References 149 and 154.

The justification provided was that the specified equipment was not located in the upper regions of the containment where

-stratification of steam would take place. Therefore, the actual containment temperature profile with a maximum of 276*F was utilized as the required environmenlal qualification profile in lieu of the NRC requirement for this equipment.

117

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Long term containment pressure/temperature responses were originally provided by Reference 74 and were incorporated as part of BGE's submittal to the NRC in Reference 76.

Due to plant changes and re-analysis, since this initial NRC submittal, the bounding containment temperature/pressure profiles have changed. The current profiles are identified in UFSAR, Section 14.20.

During the time frame of the DOR guidelines (1979), new information began to surface regarding MSLB analyses. This new information revealed that UFSAR MSLB analyses may not have identified the "worst case" MSLB with regard to peak temperature. The NRC conducted analyses (References 166 and 167) which recognized the fact that temperatures resulting from an MSLB could be as much as 100 - 150°F higher than the predicted LOCA temperature for a short period (60 - 100 sec) early in the MSLB accident. However, Reference 167, "Generic Task A-21 Mainstearn Line Break Inside Containment", stated that due to the "short duration of the temperature spike, the low heat transfer coefficients associated with a super-heated "

environment, and the heat capacity of the affected safety-related equipment, the equipment itself would not be expected to exceed the (LOCA based) temperature to which it had been qualified."

The DOR guidelines (Reference 168) section 4.2.1 stated specifically that "Equipment qualified for a LOCA environmeni is considered qualified for a MSLB accident environment in plants with automatic spray systems not subject to disabling single component failures." Thus, since Calvert Cliffs does have redundant automatic containment spray trains, the electrical equipment is considered to be qualified for an MSLB environment according to Reference 168 NRC criteria.

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Subsequently, in 1984, the NRC issued 1E Notice 84-90 (Reference 169) to reiterate the issue regarding the effect of superheated steam during an MSLB on equipment environmental qualification. Based on the above information there was/is no reason to perform additional analyses for IE Notice 84-90.

According to Reference 169, this means that although the containment temperature may rise to a super-heated value which exceeds the existing environment qualification envelope, the cooler equipment will become "insulated" by a layer of condensate at a saturation temperature corresponding to the containment pressure. For this reason, the equipment surfaces will remain at a temperature less than or equal to the saturation temperature.

Subsequent to the above, a POSRC 01 was created (Reference 170) which required a re-evaluation of small break MSLBs on containment temperature. This 01 was resolved utilizing the above NRC generated methodology presented in References 166, 167 and 168.

Therefore, although the potential exists to experience short term (60-100 sec) MSLB peak temperatures significantly higher than the existing LOCA temperatures, the EQ equipment is considered qualified to these higher MSLB temperatures when qualification to LOCA conditions has been demonstrated.

An additional evaluation of NRC IE Notice 84-90 was conducted by NEU and documented in Reference 171 with the same conclusions as discussed above.

During the Steam Generator Replacement Project, the above NPRC SER condition was modified. The modification was based on industry experience gained relating to MSLB super heat since the DOR Guidelines originally addressed the issue.

Commitment change tracking #CT200200010 was approved, modifying the above NRC SER condition as follows:

Use of the steam saturation temperature corresponding to the total building pressure (partial pressure of steam plus partial pressure of air) versus time will provide an acceptable margin for either a postulated LOCA or MSLB, whichever is controlling, as to potential adverse environmental effects on equipment, with the following ,xceptions:

119

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1. Use of the steam saturation temperature corresponding to the vapor (partial pressure of the steam only) versus time can be utilized, for evaluating short term (60-150 seconds) high temperature transient of an MSLB, when it can be demonstrated that the equipment will be covered by a condensate layer at a temperature corresponding to the saturation temperature of the vapor at the partial pressure of the vapor. It must also be shown that this condensate layer will remain on the equipment (i.e., not evaporate off) throughout the short-term high temperature MSLB transient (i~e., the time that the containment air space temperature is above the temperature of the condensate layer on the equipment).

2. Use of the containment temperature versus time as provided in the UFSAR Chapter 14 analysis can be utilized when it can be shown that the equipment is not located in the upper regions (conservatively estimated to be above the mid-point (i.e., 100' elev.) of the containment), potentially subjected to higher than average (i.e., UFSAR analyzed) LOCA/MSLB temperatures.

CCNPP is utilizingException #l(above) for the MSLB. CCNPP Calc #CA05892 (Reference 132), Section 8.0, provides a discussion/analysis demonstrating that presently installed equipment will remain covered by a condensate layer during the high short term temperature transient of the MSLB, therefore, the use of the MSLB steam saturation temperature corresponding to the vapor (partial prssure if steam only) is justified.

For new equipment installations see Section 5.5.2.a. I (LOCA event) for guidance. In addition, as also discussed in CA05892, Section 8.0, (Reference 132) the MSLB Tsai-steam temperature profile is enveloped by the LOCA temperature profile, therefore, the LOCA temperature is used to qualify equipment to the MSLB.

A conservative representation of MSLB temperature, pressure and humidity inside containment is shown in the LOCA event (Section 5.5.2.a.1).

b. Radiation

1) LOCA General area and component specific LOCA doses were determined in accordance with NUREG-0588 criteria and documented in Reference 83.

120

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 APPENDIX F DETERMINATION OF TAGAMI CORRELATION COEFFICIENTS FOR LOCA TYPE H21 121

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud ECP-11-001022 August 2012 This appendix is provided to show the method of obtaining coefficients for the Tagami heat transfer correlation shown in Table 6.4. The LOA type chosen for this demonstration is H21.

As shown in the figure, the first peak for pressure is reached in about 50 seconds. Zooming in the time first peak, the actual time to the first pressure peak is about 56 seconds.

122

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 The break mass flow rates, related enthalpies, heat rate, and integrated heat using the trapezoidal method are tabulated below.

TI E A ATE E THALPY HEAT ATE TOTAL HEAT (i0) (I /hr) u/I u/an U 0.010 0 1.1 0 0.0 0 1107 000 1.1 1 10 .77 77 0. 1 0.100 4 7 00 1 . 1 0 771 1 10 .1 0.1 0 0 100 11.4 11 111.11 14

0. 01 1 00 11. 1 117174 . 4 4 4 1.07

0. 1 77 0 00 11.7 11 14 1. 1 10 .1

0. 01 7 0 00 1 .1 114447 0.41 704 7

0. 1 70 4 00 1 . 1141 4 7. 4 7 7 0.

0.401 7 00 1. 1140 7 . 44 .7 0.4 1 7 00 1. 1140 0.7 41 17.47

0. 01 7007 00 1 .4 1141 4.1 70.

0. 00 71 00 1. 114 .44 711 417. 04 0.700 70 7700 1 .74 114 710 .7 407.1

0. 00 7 400 1.4 11 7 .7 40414 .0

0. 00 10 00 14.0 1141 444.4 10 441 .4 1.000 0 00 14. 11 1. 7 11 0.

1. 00 0000 17. 11 1 .1 17 1 .0

.000 0 400 .7 11 41 0. 01 0 1.

. 00 7 00 7. 4 1111 1 10 40.

.000 400 .1 10 71. 41 .7 4.000 774000 10 1 .11 44 04 0 .04

.000 7 00 4 .0 1017 07 .7 0 10.000 4 10400 .7 101 4100.

1 .000 44 4 400 0. 1 77 1 .7 14174 14 .4 0.000 41 1 00 7 07 17.14 17 1 00 .1

.000 7 00 0.4 74 .14 1 0 4 17.

0.000 001 100 0.7 4 4.7 4 4477.

.000 1 40 00 7 4. 40 1.1 7.

40.000 11 00 7.14 4 .4 77 4 4 .000 7 140 7.7 1 41. 0 070 .4 0.000 100 1170. 11 70. 0 7.

0. 00 01 410 11 7. .71 044040 1.004 01 00 1 00. 441 . 4 04 41.

1. 04 44 70 1 .0 111. 0 17

.00 1 0 11. 4 77 0 7 77.7

.0 11 0 11 .14 10 10 0

.00 07 0 11 10 0 7 07 4.

. 01 0 11 7.0 10 71 07 1 4.00 4 0 1 00. 10 1 .47 07 71.

4. 01 0 47 0 1 04 10 1 0. 7 0 4.

.000 0 1 10.4 1074.101 0 7 4 .1

. 00 40 0 11. 1 4. 0 1.

.000 1 74140 11. 71 7.7107 0 407.

. 00 1 0 1 17. 7 .0 0 7 4.7 7.000 1177 10 1 .11 400 41. 7 10

7. 00 17 1 47.41 1 4 10 4.

.000 0 1 47.41 0 1041 1 As seen in this table, the integrated heat up to the time of the first peak pressure is about 3.1 E8 Btu. Therefore, for the Tagami correlation, tp = 56.00 and U= 3.1E8 Btu. These values were 123

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS I & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 entered into Table 4 of heat conductors surface options of GOTHIC for heat transfer coefficient and was observed that the new values converged rapidly (except for the value of the peak pressure, which drops slightly from its previous value):

Therefore, the peak pressure for LOCA type H21 is about 49.3 psig.

124

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 APPENDIX G DETERMINATION OF CONTAINMENT INITIAL REALTIVE HUMIDITY 125

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 P..

4 NUCLEAR ENGINEERING UNIT May 26, 1994 NEU 94-162 TO: J. A. Mihalcikipl-FROM: A&Massoud

SUBJECT:

Determination Of Initial Containment Relative Humidity For Safety Related Containment Response Analysis.

References:

I) GOTHIC Containment Analysis Package User Manual, Version 4.0. Numerical Applications Inc., September 1993.

2) Containment Air Cooler Monitoring Log For Units I and 2, Spring, Summer, And Fall 1993, From Sean O'Conner (ASE) To NEU This memo documents the containment relative humidity to be used in all containment safety related issuesi including the UFSAR Chapter 14.20.

I INTRODUCTION All CCNPP containment response analyses have traditionally used a containment initial relative humidity of 50%. During the current UFSAR Chapter 14.20 upgrade, this value was re-evaluated indicating that a more conservative value should be used in the analysis.

A higher initial relative humidity is less conservative as, for a given initial pressure and temperature, it minimizes the mass of non-condensable gases in the containment. To show the effect of relative humidity on containment peak pressure, the GOTHIC containment code (Ref. 1) was used to analyze two otherwise identical sets of input data. In one case, the initial relativehumidity is assumed to be I% and in the other 100%. The peak pressure is affected by as much as 0.5 psi, as shown in Figure I.

CONCLUSION A weighted average method.is used in conjunction with-measured data to calculate a realistic relative humidity of 20% to be used in the. ontainment response"relaitedsafet yanalysis:

• 126

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 May 26, 1994 NEU 94-162 Page 2 of 3 DETAILS An initial relative humidity, as required by all containment analysis codes, should be based on a realistic value, representative of the operational condition. To make such realistic determination, some typical values for relative humidity, as measured during the Summer, Fall. and the Winter of 1993 (Ref. 2) are used.

An inspection of the measured data for 1993, as presented in Table 1, indicates that for this period, the lowest relative humidity is 19 and 17% for Units I and 2, respectively. Selection of the minimum value for relative humidity, would be unreasonably conservative, as it is the representative of a very short period. A more reasonable approach is to use a weighted average relative humidity which takes into account the actual duration at which the relative humidity has been in cffct.

The obtained data were used in the Excel spreadsheet which provided the statistical data presented in tables 3 and 4 for Units I and 2, respectively. According to these tables, a mean relative humidity of 30% with a standard deviation of about 3.5% exists for Units t and 2 in 1993. Using a simplified approach, a relative humidity with 95% confidence can be obtained for Units I and 2 by multiplying the number of days by 5%.

This gives a 4.65 days for Unit I and 4.9 days for Unit 2. By inspection in Tables I and 2, it can be concluded that there is a 95% confidence that the relative humidity for Unit I stays above 24% and for Unit 2 above 23%. As a result, a relative humidity of 20% is conservatively recommended to be used in the safety analysis of containment.

9 Table I Duration For Relative Humidity For Unit I 0 (%) No Of Days 19 1 24 6 25 2 26 6 27 2 28 10 29 3 30 7 31 5 32 1I 33 24 34 10 35 4 36 2 127

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 May 26, 1994 NEU 94-162 Page 3 of 3 Table 2 Duration For Relative Humidity For Unit 2 q (%) No Of Days 17 1 18 1 20 1 23 3 24 2 25 1 '/

26 7 27 2 28 4 30 5 31 7 32 21 33 19 34- 21 35 1 36 2 Although this value was calculated based on the 1993 data, it can be applied for general use, as these are typical operational data.

Nuclear Engineering Unit MM/pml Attachments: 1. Figure 1: Containment pressure versus time

2. Tables 3 and 4: Statistical Characteristics For Units I and 2,

3. Measured Data for Units I and 2 cc: W. J. Lippold M. T. Finley File: Analysis, Containment Response

CONTAINMENT RESPONSE ANALYSIS IN SUPPORT OF CCNPP UNITS 1 & 2 LAR CA07786, Rev. 0000 M. Massoud E P-11-0010 August 2012 0

TAMB3 Statistical Characteristics For Unit I Relative Hmidity Description Value Mean 30.6559 Standard Error 0.3587 Median 32.0000 Mode 33.0000 Standard Deviation 3.4594 Variance 11.9673 Kurtosis 0.2248 Skewness -0.8795 Range 17.0000 Minimum 19.0000 Maximum 36.0000 Sum 2851.0000 Count 93.0000 Confidence Level (95%) 0.7031 129