Analyze the case problem below.

Directions and Questions: 

1. Navigate to the Refraction simulation with PhET at:

https://phet.colorado.edu/sims/cheerpj/nuclear-physics/latest/nuclear-physics.html?simulation=nuclear-fission

(It takes a few minutes to load)

Part 1:Exploration

In this section you will familiarize yourself with the controls

General: 

∙ Be sure to try all the different tabs at the top of the simulation. 

∙ You can Pause the sim and then use Step to incrementally analyze. 

Fission: One Nucleus Tab: 

∙ Fire the gun to shoot a neutron at the Uranium nucleus and make it decay. 

∙ After the Uranium nucleus decays, press Reset to start over with a new one. Chain Reaction Tab: 

∙ Add a containment vessel, fill it with U-235 and U-238, and fire the gun to create a chain reaction.

 ∙ Grab the edge of the containment vessel and drag it in or out to change the size. 

Nuclear Reactor Tab: 

∙ Fire neutrons to create a chain reaction. Moving the control rod adjuster out of the reactor will allow the reaction to spread more quickly. 

• Click on ‘Run Now’ and select the tab that says ‘Fission: One Nucleus’

Fission: One Nucleus:

Experiment with shooting the neutron gun and watch what happens.  

What happens when the U-235 nucleus is “hit” with a neutron?  There are a number of things that happen here, describe all of them in as much detail as you can.  Use the pause button when needed

Select the “Chain Reaction” tab at the top.  Experiment with changing the settings and shooting the neutron gun and watch what happens.  Then answer the questions below.

1. Click the ‘Reset All’ button and then set the initial number of U-235 nuclei to 100 and U-238 to 0.  What happens when you fire the neutron gun?
   
   
2. Explain what makes this a “chain reaction”.
   
   
3. Click ‘Reset’ and then set the initial number of U-238 nuclei to 100 and U-235 to 0.  Explain what happens when you fire the gun.  Does this cause a chain reaction?  Try multiple times to start a chain reaction with the U-238. Explain why this happens.
   
   
4. Set the initial numbers of U-235 nuclei and U-238 nuclei to the numbers in the table below.  Record your results.  

What happens to the reaction as the proportion of U-238 nuclei increases?  Explain why this happens.

Part 2: Nuclear Reactor

Directions and Questions

Select the “Nuclear Reactor” tab at the top.  Experiment with changing the settings and firing the neutrons and watch what happens.  Then answer the questions below.

5. Watch very closely to the fission reactions as they happen.  Specifically watch what happens to the loose neutrons after the reaction.
   a)  What happens if the neutrons hit another nucleus?
   
   b)  What happens if the neutrons hit a control rod?
   
   

6. Compare the chain reaction that occurs when the control rods are inserted further into the reactor versus when they are pulled all/mostly out of the reactor.
   

7. The bar graphs on the right of the display show the “Power Output” and the “Energy Produced”.  What is the difference between these two quantities?

Step 3. Respond
Write a 300-word summary of your lab and your reflections on it. Include the answers to the questions given.

Step 4. Share
To share your work, click on the “Reply” button under this post and paste your work into the “Message” box. Make sure to reference others’ intellectual property when necessary. All references should follow 7th Edition APA formatting. For further instructions, see the resource on the Himmelfarb Health Sciences Library: APA citation resource (N.B. references are excluded from word counts).

Item A is  .…. because….  My suggestions for improvement are….
Item B is  .…. because….  My suggestions for improvement are….
Item C is  .…. because….  My suggestions for improvement are….
Item D is  .…. because….  My suggestions for improvement are….

OPTIONAL Step 6: Interact (10 minutes)

If you would like to, you can reply to your peers' posts in a respectful and professional manner. Ensure that your post engages your peers' ideas by including a reflection on their comments, sharing ideas of other potential difficulties and parties involved, or asking thought-provoking questions. If a peer comments on your posting, please reply. To post a reply, click “Reply” on a particular discussion, write your feedback and then click on “Post to forum.”

OPTIONAL Step 7: Interact (10 minutes)

If you would like to, you can reply to your peers' posts in a respectful and professional manner. Ensure that your post engages your peers' ideas by including a reflection on their comments, sharing ideas of other potential difficulties and parties involved, or asking thought-provoking questions. If a peer comments on your posting, please reply. To post a reply, click “Reply” on a particular discussion, write your feedback and then click on “Post to forum.”