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“Mechanical Properties of Nuclear Grade Graphite at High Temperatures and

Pressures”By: Matt Luedeman, Peter Wells, Chris DykeAdvisor: Jay McCormackClients: Dr. Karl Rink Dr. Akira Tokuhiro

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Overview Problem Overview

Testing Procedures

Vessel Requirements

Heating Components

Vessel Sizing

Future Plans

Questions

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Problem Overview

Purpose: The Next Generation Nuclear Power Plant (NGNP) uses a graphite pebble bed as a neutron moderator. Dust creation PEBBLES Code Unknown properties of nuclear grade graphite

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Project GoalsTwo main parts:

Create testing procedures for finding Young’s/Shear Modulus, Poisson’s Ratio Static/Kinetic Coefficients of Friction.

Create a heated pressure vessel that can simulate the environment in a nuclear reactor.

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Testing Procedures

Young’s Modulus

Shear Modulus

Coefficients of Friction

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Vessel Requirements

Vessel Requirements Temperature: 700 C Pressure: 7 MPa Testing Space: 12” Diameter, 12” Length Room for Heater Viewing Window

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HeaterFiber Insulated Resistance Wire Heater from

Zircar Ceramics: Custom Size: 16” Length, 16” OD Insulation included Time to heat Temperature Control

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Temperature ControlVariable transformer:

Varies power to heaterControls heater temperatureThermocouples used to take temperature readings

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Electrical Input Provide power to heater while still keeping seal Power feed-through must be rated to

withstand: Pressure Temperature of outside of insulation

Insulated standoff used

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Vessel SizingCylinder Requirements:

18” L, 16” IDThickness dependent on temperature and pressure

FlangesStandard Size to fit on Cylinder

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According to the ASMEstandards for pressurevessel design a 5/8” cylinder thickness was required

Fiber insulated heatertemperature graph fromZircar Ceramics

Cylinder Thickness

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Flanges

Slip-On Flanges Size based on standard flange size to fit

around pipeBlind Flanges

A thickness of 3.25” was chosen based on the temperature and pressure they will see

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Bolts/Gaskets 20 Bolts are used on each side of

the vessel Special high temperature gaskets

are used to seal the vessel

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FEA

In order to analyze the stresses seen by each component of the vessel, a computer simulation was performed using finite element analysis software.

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Viewing Window/Burst Disk

We need a viewing window for: Conducting Testing Observing Equipment

A burst disk will be added for safety purposes

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Future Plans

Fabricate burst disk and windowPerform Hydrostatic assessmentComplete temperature analysis to

determine requirements for insulation

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