CHAPTER 5: ENERGY RESOURCES SECTION 3: NUCLEAR ENERGY

WHAT ARE WE LEARNING TODAY? 1.WHAT HAPPENS DURING A NUCLEAR FISSION REACTION? 2.HOW DOES A NUCLEAR POWER PLANT PRODUCE ELECTRICITY? 3.HOW DOES A NUCLEAR FUSION REACTION OCCUR? KEY TERMS: NUCLEUSNUCLEAR FISSION REACTOR VESSELFUEL ROD CONTROL RODMELTDOWN NUCLEAR FUSION

DISCOVER ACTIVITY: WHY DO THEY FALL? 1.LINE UP 15 DOMINOES TO FORM A TRIANGLE. 2.KNOCK OVER THE FIRST DOMINO SO THAT IT FALLS AGAINST THE SECOND ROW OF DOMINOES. OBSERVE THE RESULTS 3.SET UP THE DOMINOES AGAIN, BUT THEN REMOVE THE DOMINOES IN THE THIRD ROW FROM THE LINEUP. 4.KNOCK OVER THE FIRST DOMINO AGAIN. OBSERVE WHAT HAPPENS. THINK IT OVER SUPPOSE EACH DOMINO PRODUCED A LARGE AMOUNT OF ENERGY WHEN IT FELL OVER. WHY MIGHT IT BE HELPFUL TO REMOVE THE DOMINOES AS YOU DID IN STEP 3?

NUCLEAR ENERGY -NUCLEUS-THE CENTRAL CORE OF AN ATOM THAT CONTAINS THE PROTONS AND NEUTRONS TREMENDOUS -NUCLEAR REACTIONS – REACTIONS THAT INVOLVE THE NUCLEI = TREMENDOUS AMOUNT OF ENERGY!! -TWO TYPES OF NUCLEAR REACTIONS = FISSION AND FUSION I. NUCLEAR FISSION- A. NUCLEAR REACTIONS CONVERT MATTER INTO ENERGY B. ALBERT EINSTEIN = DEVELOPED A FORMULA THAT DESCRIBED THE E= MC 2 RELATIONSHIP BN ENERGY AND MATTER = E= MC 2 E=ENERGY M=MASS C = SPEED OF LIGHT E=ENERGY M=MASS C = SPEED OF LIGHT

C. FISSION REACTIONS- 1. NUCLEAR FISSION- THE SPLITTING OF AN ATOM’S NUCLEUS INTO TWO SMALLER NUCLEI. A. UNSTABLE NUCLEUS OF A LARGE ATOM IS NEEDED EX: URANIUM-235 WHEN THE NEUTRON HITS THE U-235 NUCLEUS, THE NUCLEUS SPLITS APART INTO TWO SMALLER NUCLEI AND TWO OR MORE NEUTRONS.

B. CHAIN REACTION OCCURS WHEN THE THREE NEW NEUTRONS STRIKE ANOTHER NUCLEUS D. ENERGY FROM FISSION- 1. HUGE EXPLOSION OCCURS IF THE REACTION IS NOT CONTROLLED EX: ATOMIC BOMB - FEW KG OF MATTER EXPLODE WITH MORE FORCE THAN SEVERAL THOUSAND TONS OF DYNAMITE 2. WHEN CONTROLLED, THE ENERGY RELEASED IS IN THE FORM OF HEAT 3. THIS HEAT IS USED TO GENERATE ELECTRICITY

II. NUCLEAR POWER PLANTS IN A NUCLEAR POWER PLANT, THE HEAT RELEASED FROM FISSION REACTIONS IS USED TO CHANGE WATER INTO STEAM. THE STEAM THEN TURNS THE BLADES OF A TURBINE TO GENERATE ELECTRICITY. PG. 177, FIGURE 14 A.REACTOR VESSEL – THE PART OF THE NUCLEAR REACTOR WHERE NUCLEAR FISSION OCCURS.

1. FUEL RODS- RODS OF U-235 A. SEVERAL ARE NEEDED TOGETHER = FISSION REACTION 2. CONTROL RODS- A CADMIUM ROD USED IN A NUCLEAR REACTOR TO ABSORB NEUTRONS FROM FISSION REACTIONS A. INSERTED BN THE FUEL RODS =SLOWS THE REACTION DOWN B. CAN BE REMOVED TO SPEED THE REACTION UP IF NECESSARY

B. HEAT EXCHANGER- 1. WARM WATER ENTERS AND BOILS WATER TO PRODUCE STEAM 2. STEAM RUNS THE ELECTRICAL GENERATOR 3. STEAM IS THEN CONDENSED AND PUMPED BACK TO THE HEAT EXCHANGER

C. THE RISKS OF NUCLEAR POWER- 1. MELTDOWN- WHEN FUEL RODS GENERATE SO MUCH HEAT THAT THEY START TO MELT EX: CHERNOBYL, UKRAINE - DOZENS DIED FROM EXPLOSIONS CAUSED BY THE HEAT - RADIOACTIVE MATERIALS ESCAPED INTO THE ENVIRONMENT 2. HARD TO DISPOSE OF THE RADIOACTIVE MATERIAL - RADIOACTIVE MATERIALS REMAIN ACTIVE FOR THOUSANDS OF YEARS

III. THE QUEST TO CONTROL FUSION- A. NUCLEAR FUSION- THE COMBINING OF TWO ATOMIC NUCLEI TO PRODUCE A SINGLE LARGER NUCLEUS IN NUCLEAR FUSION, TWO HYDROGEN NUCLEI COMBINE TO CREATE A HELIUM NUCLEUS, WHICH HAS SLIGHTLY LESS MASS THAN THE TWO HYDROGEN NUCLEI. THE LOST MASS IS CONVERTED TO ENERGY. 1. COULD PRODUCE MORE ENERGY PER UNIT OF ATOMIC MASS THAN NUCLEAR FISSION 2. FUEL FOR THIS TYPE OF REACTION IS AVAILABLE 3. WILL PRODUCE LESS RADIOACTIVE WASTE 4. UNFORTUNATELY, PRESSURE AND TEMP REQUIRED ARE IMPRACTICAL AT THIS TIME