August 24, 2011 Presentation to Colorado School of Mines

Transcription

1 HEAVY-METAL NUCLEAR POWER: Could Reactors Burn Radioactive Waste to Produce Electric Power and Hydrogen? Eric P. Loewen, Ph.D. President, American Nuclear Society August 24, 2011 Presentation to Colorado School of Mines 1

2 About ANS 2 Professional organization of engineers and scientists devoted to the applications of nuclear science and technology 11,500 members come from diverse technical backgrounds Dedicated to improving the lives of the world community within government, academia, research laboratories and private industry 2

3 Times Square,

4 Careful What You Do Your R&D On 4

5 5

6 Our Journey Together Heavy Metal Fast Reactor Physics LBE Corrosion Issues Polonium Issues Basic Reactor Design Four Metal Reactor Missions Once Through Fertile-Free TRU Burner Fertile-Free MA Burner Fertile TRU Burner 6 6

7 Heavy Metal Fast Reactor Physics 7 7

8 The Waste 8 8

9 Spent Reactor Fuel 9 9

10 Metal Cooled Reactors: A Fast History Soviets heavy-metal program began in the 50s Culminated with a reactor in an attack submarine Seeking to apply military technology to commercial use Russia s experience sparked interest here for US metal cooled reactors 10 10

11 Fast Reactors: Produce hard neutrons that maintain a high velocity as they strike lead High velocity neutrons explode fissile atoms into two fragments Transmutation = large radioactive atomic species converted into a smaller, radioactive atom 11 11

12 Differences With Fast Reactors Operate at higher temperatures Neutrons are traveling at relatively high speeds Reactor can consume its waste and waste from other reactors Addresses the waste problem It s a sustainable energy source 12 12

13 Fission Energy: Fast and Slow Neutrons 13 13

14 Spent Fuel & Transmutation 14 14

15 Neutron Speeds 15 15

16 Fissions per Absorption Neutron Physics: Cross Sections Thermal Fast Actinide

17 LBE Corrosion Issues 17 17

18 Mass Transfer Corrosion Dissolution Heat in Oxygen Potential Heat out Precipitation Oxide layer Ni Fe CR Pb flow + O 2 PbO Ni CR Fe Surface morphology Hot Pipe wall Cold MIT - Advanced materials - Development of materials INEEL - Commercial materials - Chemical composition Collaboration 18

19 INEEL Testing Apparatus 19

20 Corrosion Control Requires Control Requires O 2 Control 20 20

21 316 SS Cross Section Exp: 500 C, 100 h Lead Oxidation As & Sb FeAs Reduction FeAs Pb

22 HT9 SEM Results 22

23 Polonium Issue 23 23

24 The Polonium Issue in LBE-Cooled Reactors Po Release - PbPo evaporation - PbPo+H 2 O H 2 Po+PbO Po Extraction Po Deposition CORE 24 Accidental Pb-Bi spill Bi n Bi Po Po Production t1 / 2 5 days t1 / Po chemical form in LBE: 99.8% PbPo, 0.2% elementary Po days 206

25 Alkaline Experimental Steps 25

26 Two Different NaOH Sampling Methods 26

27 Basic Reactor Design 27

28 Basic Reactor Design 28 28

29 The Heavy Metal Reactor 29 29

30 LBE Reactors Lead-bismuth eutectic safety advantages: Higher specific heat Higher density Lower neutron absorption Higher scattering High boiling point 30 30

31 LBE Reactors Heavy-metal liquid s high boiling point, heat of vaporization, reduces the possibility of coolant loss and catastrophic core melting Lead remains liquid and only boils at 1,750 C Lead-cooled system can be operated at atmospheric pressures preventing common light-water reactor accidents 31 31

32 Additional LBE Safety Features: Passive residual heat-removal system limits maximum temperature to 600 degrees below boiling point Nuclear fuel is highly soluble in the coolant, density higher than nuclear fuel Can naturally shut down fission reactions Reactor might operate totally on natural circulation 32 32

33 Heavy Metal Reactor Missions 33 33

34 Four Heavy Metal Reactors 1. Once through 2. Fertile-Free TRU Burner 3. Fertile-Free MA Burner 4. Fertile TRU Burner 34 34

35 #1 Once Through Cheaper electricity Has harder neutron spectrum with incore breeding and excellent safety characteristics 35 35

36 Once-Through Scheme 36 36

37 Burning Waste: Fertile vs. Non-Fertile Traditional reactors have fertile material Thorium becomes uranium Uranium becomes plutonium Replacing fertile material with waste changes the reactor s performance Control is more difficult, economic penalties 37 37

38 #2: Fertile-Free Transuranics Burner Achieve maximum burning of transuranic waste Recycling usually done in 18-month increments but can be extended Security advantage: virtually impossible to produce fissile material for weapons 38 38

39 #2: Fertile-Free Reactors (con t.) Most promising for burning old and existing radioactive waste: 700-megawatt-thermal modular reactor could burn 0.2 MT TRU/yr Represents 2/3 annual output of a large 3,000 megawatt light-water reactor How many to break down existing waste? Need small reactors running for 40 years 39 39

40 #2: Fertile-Free Reactors, (con t.) Multi-pass: 99.9% reduction in long-lived transuranics-waste inventory Would reduce the radiotoxicity of consolidated final waste stream to comparable amount of uranium ore would emit in years 40 40

41 #3: Fertile-Free Minor Transuranics Burner Fertile-Free Minor Transuranics Burner Designed to maximize the rate minor transuranics are destroyed without destroying plutonium Plutonium is separated and burned in light water reactor Minor transuranics burned in heavy reactor 41 41

42 #3: Fertile-Free Minor Transuranics Burner (con t.) Fertile-Free Minor Transuranics Burner, con t. Fewer heavy-metal reactors would be needed 0.8 percent plutonium, 0.1 percent minor transuranics in light water reactor spent fuel 42 42

43 #4: Fertile TRU Burner 43 To produce economical electricity and burn transuranics Would employ thorium Creates supplemental fuel, improves reactor performance and stability Thorium is three-times more abundant than uranium Thorium takes up more room where transuranics reside so more reactors are needed 43

44 Reduce, Reuse, Recycle -- Safely 44 44

45 Multi-Cycle Scheme 45 45

46 What Now? 46 46

47 Join ANS! 47 47

48 Thank You! For more information contact the ANS Public Outreach department at or visit ww.ans.org

49 Information Source This presentation is derived from an ANS Special Issue of Nuclear Technology, September, 2004 and Heavy-Metal Nuclear Power: Could an unconventional coolant enable reactors to burn radioactive waste and produce both electric power and hydrogen? American Scientist, Volume 92, 2004 November-December 49 49