MARY NORRIS, STEPHENVILLE HIGH SCHOOL

LIN SHAO, ASSISTANT PROFESSORNUCLEAR ENGINEERING TEXAS A&M

UNIVERSITY

The research question: How Does Radiation Affect the Components

in a Nuclear Reactor?

Lin Shao

Education Ph.D., Physics, University of Houston, 2001B.S., Nuclear Physics and Technology, Peking (Beijing) University, P. R. China, 1997

Areas of Interest Materials science and nanotechnology Radiation effects in nuclear and electronic materials Ion beam analysis

Main Research Group: Nuclear Materials and Fuel Cycles

•Pressure vessel

•Pressuerizer

• Steam generator

•Pump

•Containment

Pressurized water nuclear reactor

Uranium Enrichment U-238 U235

Fuel Rod and Fuel Assembly

Fission Reaction Stray neutrons cause damage to the metal of surrounding the fuel rods

VacancyInterstitial

Disloca-tion loop

Cluster

Interstitialcy

Damage at the molecular level

Why we care

In nuclear reactors, many energetic ions keep bombarding reactor walls. This bombardment can cause bubbles, cracks and voids. This makes the reactor unsafe.

We want to know when and how this will happen, but do not want to wait 20 years.

Accelerators are used to simulate the environment

Five accelerators ion energy from 10 keV - 1.7 M eV

Ion Beam Analysis

view port

Ion beam

RBS - Rutherford Backscattering for depth profiles of complex thin films (up to a few microns thick and down to a few nm depth resolution). PIXE- Particle (usually proton) Induced X-ray Emission (ppm sensitivities). NRA - Nuclear Reaction Analysis (isotope specific). IBIC - Ion Beam Induced Charge.STIM - Scanning transmission ion microscopy.

Summer Research

Particle Ion Irradiation Effects on the Venus Flytrap

Leanne Kristek

Gain insights into possible biological effects on living tissue of Venus flytraps

Possible reasons for dysfunction: Trigger hair damage Ion channels inhibited

Identify the critical dose level for noticeable function failure

Understand the signal transfer mechanism in Venus flytraps more comprehensively

Implications

Venus Fly Trap with trigger hairs

Data Collection

Record speed of closure before, after, and possibly during proton and alpha irradiation Use a high speed camera, e64 Hotshot Mic Use SCRIM program to determine

Energies to use Number of damage events for each given energy

View structural tomography before and after irradiation to detect ion-solid interaction damage (especially of ion channels, plasmodesmata, and stomata) Use Scanning Electron Microscope

Question I

If the leaf does indeed close once bombarded with the ion beam, are the ion channels of the plant affected? If so, how? Ion potentials involve Cl−, K+, Ca2+, and H+

If the leaf will not reopen, then how to collect data? Could try using an electrical current to reopen Could try irradiating soil instead of directly on leaf

Accelerator Attachment

- Faraday Cup- Scintillation Crystal- Sample Holder

Faraday Cup

Collects charged particles in a vacuum Minimal to no backscatter

Placed before the Venus Flytrap

Measure the resulting current (I) to determine amount electrons (N) hitting target in time (t):

Scintillation Crystal

Ionizing radiation causes luminescenceThus allowing a visual to focus beam

Questions

Does the ion beam act on the sensitive filaments or the cells of the leaf itself?

Do the trigger hairs and/or cells repair themselves? Signs of repair

Assel Aitkaliyeva George Wei

Tianyi Chen

Danny Galicki

Justin General Josey Wallace

McIan Amos

Ion & Materials Research Facility (Ion Beam Lab, Accelerator Lab)

Lin Shao, Lab Director

students

M.S. students

Undergraduate

Alvaro Aranibar

Leanne Kristek Lloyd Price

Thank You!!!Dr. Shao and his staff have been incredibly welcoming and gracious. They have willingly taken time from their busy schedules to help and answer questions whenever I asked.

Additional Thank You’s

TAMU E3 Program

National Science Foundation

Nuclear Power Institute

Texas Workforce Commission