Study of Thermally Induced Currents in High Range Radiation Monitor - PowerPoint PPT Presentation

Study of Thermally Induced Currents in High Range Radiation Monitor Cables (1813) Team: Peter Nidever, Alex Cannan, Richard Ross Professor Advisor: Yang Cao Industry Sponsor: Shane Williams

Zachry Nuclear Engineering Inc. ● Located in Stonington, CT ● Provides engineering analysis services including thermal hydraulic, radiological, chemical, thermal margin, reactor core and safety analysis. ● 200 Nuclear Employees and an additional 750 Engineers within Zachry

Project Statement Main Deliverables ● Design an experimental rig to measure TICs for various coaxial cables-in-conduit configurations ● Transient 2D CFD model of one cable-in-conduit configuration used in testing ● Suggestions for improving HRRM systems to eliminate the problem of false alarms

Experimental Rig Design ● Source of temperature gradient ○ Liquid cooling/heating system. Exploring possibilities heating coils as well. ● Way to measure temperature of coaxial cable inside the conduit ○ Considering drilling small holes in conduit to wire thermocouples to cable. ● Resting all of this inside of a trough, with water-tight openings for the leads of the cable to come through ○ May be done by sealing conduit against trough ends, or by a capping system. ● Controlling the position of wire inside the conduit ○ Stiffness of wire (or lack thereof) may lead to non-uniform contact along the conduit.

General Responsibilities Everyone Zachry Approval ● Review research papers and previous ● Project Schedule experiments ● Project Statement ● Design a safe and reliable experimental rig ● Choice of cable for testing ● Experimental tests and analysis. ● Identify sources of error ● Experimental rig setup ECE Team ● Materials purchasing ● Material management and build experimental rig ME Team ● Develop transient 2D CFD model

Summary ● Explore TIC effects experienced by various coaxial cables in HRRM systems ● Design a safe and reliable test setup ● Compare temperature data obtained by experimental testing to CFD model ● Provide potential solutions to improve HRRM systems

Zachry Nuclear Engineering Inc. ● Located in Stonington, CT ● Provides engineering analysis services including thermal hydraulic, radiological, chemical, thermal margin, reactor core and safety analysis. ● 200 Nuclear Employees and an additional 750 Engineers within Zachry

Project Background ● TIC - Thermally Induced Current ● HRRM - High Range Radiation Monitor ● NRC - Nuclear Regulatory Committee ● MSLB - Main Steam Line Break ● EPRI - Electric Power Research Institute ● LOCA - Loss of Coolant Accident MSLB LOCA https://commons.wikimedia.org/wiki/File:PWR_nuclear_power_plant_diagram.svg

Project Statement Main Deliverables ● Design an experimental rig to measure TICs for various coaxial cables-in-conduit configurations ● Transient 2D CFD model of one cable-in-conduit configuration used in testing ● Suggestions for improving HRRM systems to eliminate the problem of false alarms

Experimental Rig Design ● Source of temperature gradient ○ Liquid cooling/heating system. Exploring possibilities heating coils as well. ● Way to measure temperature of coaxial cable inside the conduit ○ Considering drilling small holes in conduit to wire thermocouples to cable. ● Resting all of this inside of a trough, with water-tight openings for the leads of the cable to come through ○ May be done by sealing conduit against trough ends, or by a capping system. ● Controlling the position of wire inside the conduit ○ Stiffness of wire (or lack thereof) may lead to non-uniform contact along the conduit.

Experimental Rig Design

Experimental Rig Design

Experimental Rig Design Cont. ● Interface the thermocouple(s), cooling/heating system, and pico-Ammeter into LabView for automated control and data acquisition ● The specific design depends on the samples of cable we will receive from Zachry. ● Will also require a preliminary test to determine how long of a cable we need to obtain distinct results. ● Ultimately depends on viability/availability.

Plan of Execution Major Milestones ● Determine electrometer or picoammeter and compatible DAQ ○ Determine maximum/minimum length of cable ● Design and build experimental rig ● Create transient thermal 2D CFD model ● Compare the average surface temperatures of cable from experimental data to CFD model ● Use thermal 2D CFD model to calculate TIC effect ● Compare modeled TIC effects to experimental data

General Responsibilities Everyone Zachry Approval ● Review research papers and previous ● Project Schedule experiments ● Project Statement ● Design a safe and reliable experimental rig ● Choice of cable for testing ● Experimental tests and analysis. ● Identify sources of error ● Experimental rig setup ECE Team ● Materials purchasing ● Material management and build experimental rig ME Team ● Develop transient 2D CFD model

Summary ● Explore TIC effects experienced by various coaxial cables in HRRM systems ● Design a safe and reliable test setup ● Compare temperature data obtained by experimental testing to CFD model ● Provide potential solutions to improve HRRM systems

Deliverables • One interim design report •Documenting design concept and analytical effort •To be issued to Zachry at completion of Fall Semester • One final design report •Documenting design concept, testing procedure/results, conclusions, and lessons learned •This should include all final experimental data in digital form, CFD files and associated input & output files, data manipulation or post-processing spreadsheets, etc. •To be issued to Zachry at completion of Spring Semester, PRIOR TO the public Demonstration Day • A formal presentation •Summarizing the project development and conclusions •To the engineering staff at Zachry’s Stonington office •Prior to end of the Spring Semester

Project Background •Positive gradients in temperature result in positive Thermally Induced Currents (TICs), which show as falsely high radiation readings in the control room. •Misleading to operators while trying to assess and diagnose a potential situation inside of containment. •Could result in unnecessary evacuations. •Negative gradients in temperature result in negative TICs, which may “overcome” the “keep-alive” current in the system.

Project Scope •Analytical Portion •Develop a transient 2D CFD model of one of the cable-in-conduit configurations tested if it is determined that physical testing is feasible. •If experimental testing of cable-in-conduit configurations is not possible, Zachry will provide a set of ambient conditions and other inputs necessary to model a specific cable-in-conduit configuration. •Run the model using the transient ambient condition data from the corresponding experiment and develop a means of calculating a transient average cable surface temperature using the CFD output. •If experimental testing of cable-in-conduit configurations is not possible, use the Zachry-provided transient ambient data. •Analysis •Identify sources of error and uncertainty in the test rig and experimental process. •Considering the rated accuracies of the instrumentation used and values measured, how does this affect the validity of your results? •Address potential spatial bias in experimental temperature measurements. •Report experimental data in TIC vs Time and Temp. vs Time graphs and data sets. •Investigate and discuss reasons for any unexpected or seemingly unrealistic data. •Compare the average surface temperatures calculated by the CFD model to the experimentally measured values and discuss reasons for similarities/differences. •If experimental testing of cable-in-conduit configurations is not possible, compare to Zachry-provided GOTHIC data.

Project Scope The purpose of this project is to experimentally and analytically explore the potential TIC effects experienced by different types of coaxial cable in various configurations used in HRRM systems. •Experimental Portion •Determine what Electrometers or pico-Ammeters and compatible Data Acquisition Systems (DAQs) are available for the experimental rig. Determine the achievable Range, Resolution, and Accuracy, and Sample Rate. •Based on the available instrumentation, determine whether it will be possible to test cable-in-conduit configurations. •Length of conduit tested will need to be considered to determine an expected TIC in amps. Zachry will work with the team to make this determination by using pre-existing experimental and analytical data. •Develop a structurally, logistically, and financially feasible test setup to measure TIC in a range of coaxial cable types and configurations. •Must develop a safe means of implementing rapid temperature changes. •Must develop a reliable means of recording transient ambient and cable surface temperatures. •Preferably at multiple locations so that spatial bias may be considered. •Preferably it will be possible to sync the temperature data with the TIC data by using the same DAQ.