ML16307A490

Presentation Slides from Public Meeting Calvert Cliffs GSI-191 Resolution Update

ML16307A490
Person / Time
Site:	Calvert Cliffs
Issue date:	10/25/2016
From:	Kimberly Green Exelon Nuclear Generation Corp
To:	Richard Guzman Plant Licensing Branch 1
Guzman R
References
CAC MF8521, CAC MF8522
Download: ML16307A490 (14)

Text

Calvert Cliffs GSI-191 Program Thermal Hydraulic Analysis of Containment Response and Acceptable Head Loss Test Selection October 25, 2016

Agenda

• Introductions

• Objectives for Meeting

• Thermal Hydraulic Analysis of Containment

- Demonstrate that one CS pump will be secured prior to the onset of chemical precipitation

- Containment pressure reduces to 2.8 psig prior to containment pool reducing to 140°F

• Acceptable Strainer Head Loss Test

- Identify chemical effects head loss test applicable simplified risk-informed approach

• Staff Questions & Concerns

• Schedule for Future Periodic Meetings Calvert Cliffs Option 2b Refined Closure Plan 1

CCNPP Attendees

• Jake Smith - Director Site Engineering

• John Haydin - M&CU Engineering Manager

• Andre Drake - Lead Responsible Engineer GSI-191

• Craig Sellers - Project Manager GSI-191

• Eric Federline - Project Support Calvert Cliffs Option 2b Refined Closure Plan 2

Thermal Hydraulic Analysis of Containment

• Investigate Sump Temperature and Containment Pressure

- Large Break LOCA Events

- Cooldown Scenarios

• 2 Containment Spray Pump + 2 Containment Air Coolers - Slower Cooldown

• 2 Containment Spray Pumps + 4 Containment Air Coolers - Rapid Cooldown

• In all cases, pool temperature > 140°F when containment pressure reduces to 2.8 psig

- One Containment Spray Pump secured at containment pressure < 2.8 psig

- Chemical precipitants remain soluble until pool temperature reduces to 140°F

- Cold Leg Break, Max SI, Max Instrument Uncertainty, pool = 138.8°F @ 2.48 psig

• Cold Leg Break produces 10% to 20% less precipitate Calvert Cliffs Option 2b Refined Closure Plan 3

Thermal Hydraulic Analysis Results

• 2 CS pumps + 2 CACs

- Hot Leg Break

• Time to 140°F = 108.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />

• Time to 2.8 psig = 47.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />

• Time to secure pump = 61.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

• Pressure @ 140°F = 1.98 psig

- Cold Leg Break

• Time to 140°F = 77.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />

• Time to 2.8 psig = 63.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />

• Time to secure pump = 13.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />

• Pressure @ 140°F = 2.58 psig Calvert Cliffs Option 2b Refined Closure Plan 4

• 2 CS pumps + 4 CACs

- Hot Leg Break

• Time to 140°F = 86.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

• Time to 2.8 psig = 23.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />

• Time to secure pump = 62.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />

• Pressure @ 140°F = 1.95 psig

- Cold Leg Break

• Time to 140°F = 50.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />

• Time to 2.8 psig = 38.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />

• Time to secure pump = 11.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

• Pressure @ 140°F = 2.63 psig

Thermal Hydraulic Response After CS Pump Trip Containment Spray primary heat removal for containment pool Pressure and Temperature increase after pump trip Pressure increase can auto restart CS pump EOPs being revised to prevent auto restart of CS pump Calvert Cliffs Option 2b Refined Closure Plan 5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 10 100 1000 Containment Pressure (psig)

Time (hr)

CL Slower Cooldown HL Slower Cooldown CL Rapid Cooldown HL Rapid Cooldown 110 120 130 140 150 160 170 10 100 1000 Sump Water Temperature (F)

Time (hr)

CL Slower Cooldown HL Slower Cooldown CL Rapid Cooldown HL Rapid Cooldown

2010 Head Loss Testing - Test 5 Calvert Cliffs Option 2b Refined Closure Plan 6

• CCNPP performed a sequence of strainer head loss tests in 2010 with varying, scaled debris loads

• Test 5 is most appropriate test to use to define critical break size

-Largest amount of fiber fines with maximum head loss below acceptance criteria of 1.99 ft H20 when chemical precipitates form

• Test 5 Corresponding Plant Quantity Debris Loads

-211 lbs NUKON Fines

-542 lbs Thermal Wrap Fines

-29 lbs Generic Fiberglass

-43 lbs Temp-Mat

-206 lbs Epoxy Chips

-2269 lbs Particulate (modeled using silicon carbide)

-54.1 lbs of WCAP-16530 NaAlSi3O8

Head Loss Plot - Test 5 Calvert Cliffs Option 2b Refined Closure Plan 7

Non-Chemical Head Loss Chemical Effects Head Loss

2010 Testing Flow Rates

• 2010 testing program added fibrous, particulate, and coating chip debris at scaled design plant flow rate of 5000 gpm

• During and after addition of chemical precipitates, flow was lowered to scaled flow rate of 2400 gpm (assumed 1 CS pump and 1 HPSI pump)

• Maximum recirculation flow rate at on-set of chemical effects could be as high as 2900 gpm (1 CS pump and 2 HPSI pumps)

• Flow sweeps performed at the end of each test

-Test flow rate varied from scaled plant values of ~600 gpm to ~6000 gpm, holding for 10 minutes at various increments Calvert Cliffs Option 2b Refined Closure Plan 8

2010 Test 5 Flow Sweep Data Calvert Cliffs Option 2b Refined Closure Plan 9

Note - Plot Shows Corresponding Plant Flow Rates used in Test

Scaling Test 5 Head Loss Using Flow Sweep Data - Preliminary

• During test, break-through occurred in debris bed as chemical precipitates were introduced

• Increase maximum head loss recorded in Test 5 (1.21 feet) by ratio of flow rate increase from 2400 gpm to 2900 gpm

• This is more conservative the scaling using ration of head loss increase from flow sweeps Calvert Cliffs Option 2b Refined Closure Plan 10

Test 5 Flow Sweep Results - Preliminary

• Linearly interpolate head loss

-2900 gpm / 2400 gpm = 21% increase

• Maximum total head loss including clean strainer head loss:

(1.21 ft

• 1.21) + 0.288 ft = 1.75 ft

• Below acceptance criteria of 1.99 ft (limiting failure mode of CCNPP strainer is dearation)

Calvert Cliffs Option 2b Refined Closure Plan 11

Questions/Concerns

• Jointly Review Issues, Questions, and Concerns for Future Communication Calvert Cliffs Option 2b Refined Closure Plan 12

Next Steps

• Finalize Update of Calculations

• Present Formal Risk-Informed GSI-191 Analysis and Results

• Desire Next Meeting - 4Q 2016 Calvert Cliffs Option 2b Refined Closure Plan 13