ML16095A078

Slides for the WCGS Meeting Discussion 4/12/16

ML16095A078
Person / Time
Site:	Wolf Creek
Issue date:	04/12/2016
From:	Lyon C Plant Licensing Branch IV
To:
Lyon C, NRR/DORL/LPLIV-1
References
CAC MC4731
Download: ML16095A078 (19)

Text

Fiber Penetration and Head Loss Testing Approach Meeting with NRC April 12, 2016 1

Outline

• Purpose of Meeting

- Communicate Wolf Creek testing approach for fiber penetration and strainer head loss

• Agenda

- Overview of Wolf Creek Testing Program

- Fiber Penetration Testing Approach

- Strainer Head Loss Testing Approach 2

Strainer B Strainer A Overview of Sump Strainers 3

Overview of Testing Program

• Perform tank tests at Alden for fiber penetration and strainer head loss

• Use prototypical strainer modules for head loss testing

• Modify prototypical strainer modules for penetration testing to eliminate bridging

• Test strainer modules have same disk size, perforation size and core tube diameter as the plant strainer

• Maintain turbulence level for complete transport of fine debris 4

Flow Direction Debris Introduction

& Mixing Section Plenum Box Test Strainer To Flow Loop

Overview of Testing Program (contd)

• Use methods previously reviewed by the NRC

- Similar to recent tank tests for Florida Power & Light at Alden witnessed by the NRC staff

• Follow NEI guidance on fibrous debris preparation*

• Determine threshold debris load that meets in-vessel and head loss criteria using test results

• Projected test start date: May 9, 2016 5

ZOI Fibrous Debris Preparation: Processing, Storage and Handling, Rev. 1, Jan 2012 (ADAMS Accession No. ML120481057)

Fiber Penetration Testing Approach

• Perform a fiber-only penetration test

• Collect time-dependent fiber penetration data considering prompt and long-term penetration

• Develop a curve fit from testing data to characterize rates of prompt and long-term penetration

• Apply curve fit to quantify total fiber penetration for the fiber load of each break at bounding plant conditions

• Determine compliance with the in-vessel fibrous debris quantity limit (WCAP-17788)

• Perform 30-day extrapolation for total fiber penetration as input to ex-vessel downstream effects analysis 6

Prevent Bridging for Penetration Testing

• Modified prototype strainer to eliminate possible bridging of fiber between adjacent disks, and between the strainer and its surrounding walls

• Preventing bridging in fiber-only penetration testing allows fiber to reach the perf plates and is conservative 7

Test strainer module modification

- Remove every other disk

- Remove seismic cables

- Increase distance between edges of test strainer and surrounding walls Measured fiber penetration per unit area will be applied to the plant strainer surface area

Penetration Testing Conditions

• Prototypical pool chemistry at max pH (9.6)

• Testing temperature 120°F +/- 5°F

• Max strainer approach velocity (0.00612 ft/s)

• Prototypical fibrous debris concentrations

- Pool fiber concentration defined as total fiber quantity divided by pool volume

- Fiber concentration in test tank maintained at or below the prototypical value to allow debris bed to form slowly 8

Fiber Preparation and Introduction

• Only fines will be used for penetration testing

- Nukon sheets baked single-sided into half thickness and cut into 2 x 2 cubes

- Debris preparation per the latest NEI Guidance*

• Fiber will be added to the test tank in batches

• Batching size will increase gradually to facilitate fiber bed formation on test strainer

• Total test fiber quantity will bound the max fiber load of largest DEGB 9

ZOI Fibrous Debris Preparation: Processing, Storage and Handling, Rev. 1, Jan 2012 (ADAMS Accession No. ML120481057)

Collect Time-Dependent Penetration Data

• Penetrated fiber collected in 5-µm filter bags

• Each batch begins with a set of clean bags

• To measure long-term penetration, extended runtime and multiple bag changes will be done for selected batches

• Total runtime of the test exceeds duration from start of an accident to hot leg recirculation switchover

• A curve-fit will be developed to adequately model and bound testing results

• The curve-fit characterizes both prompt and long-term penetration 10

Head Loss Testing Approach

• Measure debris bed head loss for debris loading of various break sizes on a prototypical test module

- No modifications to test modules as done for penetration testing

• Chemical debris will not be added until all conventional debris has been introduced to test tank and head loss allowed to stabilize

• Perform flow sweeps for adjusting measured head losses to plant conditions

- After adding all conventional debris and at end of test 11

Head Loss Testing Approach (contd)

• Perform temperature sweep after adding all conventional debris to characterize debris bed

• Head Loss Test Conditions:

- Prototypical sump water chemistry at min pH (8.7)

- Test temperature approximately 120°F +/- 5°F

- Approach velocity from max strainer flow rate and net strainer surface area (0.00615 ft/s)

• Two head loss tests planned

- Test 1: Full Debris Load Test

- Test 2: Thin Bed Test

- Contingency test may be conducted depending on results of previous tests 12

Test 1: Full Debris Load Test

• Fibrous and particulate debris batched into test tank as homogeneous mixtures

• Addition of conventional debris ends when head loss is near prescribed value based on pump NPSH margin and strainer structural limit

• No alternating additions of fiber fines and small pieces 13

Test 1: Full Debris Load Test (contd)

• Cumulative conventional debris quantities of intermediate batches match debris loads of multiple break sizes

- Head loss allowed to stabilize before continuing addition

• Chemical debris batched into test tank after completing all conventional debris addition

- Head loss allowed to stabilize after each addition 14

Test 2: Thin Bed Test

• Particulate debris load for Test 2 will be informed by the threshold breaks identified in Test 1

• Particulate debris added to test tank at the beginning of test

• Nukon fiber fines added in batches until thin-bed conditions are met

• Chemical debris batched in afterwards 15

Test Debris Types Test Materials Debris Types at Plant Nukon

• Nukon Insulation

• Latent Fiber

• Cerablanket

• Fibrous Content of Thermolag Pulverized Acrylic or Silicon Flour (10 µm)

• IOZ, Epoxy and Alkyds

• Foamglas

• Particulate Content of Thermolag PCI PWR Dirt/Dust Mix*

Latent Particulate Aluminum Oxyhydroxide Aluminum Precipitate Debris 16 The size distribution of PCI PWR Dirt/Dust Mix meets requirements in Appendix VII of NEI 04-07 for surrogate of latent particulate debris

Quantity of Chemical Debris

• Evaluated chemical precipitate quantities using deterministic method per WCAP-16530-NP-A

- Max sump pool mass and temperature to increase aluminum release

- Max pH to increase aluminum release

- Conservatively higher aluminum inventory

- Max quantities of E-Glass of largest DEGB 17

Closing

• Wolf Creek is planning to use methods previously reviewed by the NRC staff

• Penetration data will be used to develop a curve fit that can be applied to any debris load (up to max for WCNOC)

• Head Loss test results will establish a threshold debris load

• Analysis will determine the threshold debris load that meets both the in-vessel and head loss criteria

• Threshold debris load will determine the break sizes that pass deterministically 18

Closing

• Questions?

19