Is there a safe future for nuclear energy? Dr John Roberts Dalton Nuclear Institute The University of Manchester

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1 Is there a safe future for nuclear energy? Dr John Roberts Dalton Nuclear Institute The University of Manchester

2 Rutherford Model of the Atom The atom The nucleus Few x m Few x m Z orbiting electrons

3 Periodic Table 235 U 92 protons, 143 neutrons, 238 U 92 protons, 146 neutrons

4 Key Themes What does safe mean? What exactly is nuclear energy? What are the future options for nuclear energy?

5 Safe?

6 Safe?

7 Safer?

8 Safer?

9 2,753

10 2,753

11 Deaths per Billion Passengers km Journeys Hours Air 0.05 Bus/Coach 4.3 Bus/Coach 11.1 Bus/Coach 0.4 Rail 20 Rail 30 Rail 0.7 Van 20 Air 30.8 Van 1.2 Car 40 Water 50 Water 2.6 Foot 40 Van 60 Car 3.1 Water 90 Car 130 Pedal cycle 44.6 Air 117 Foot 220 Foot 54.2 Pedal cycle 170 Pedal cycle 550 Motorcycle Motorcycle 1,640 Motorcycle 4,840

12 Road Deaths by Age Source: Reported Road Casualties Great Britain: 2009 Annual Report

13 Deaths per TWh Source: IBM

14 World Electricity Generating Capacity Total 20,269 TWh Coal 40.8% Hydro16.2% Other (inc Wind) 2.8% Oil 5.5% Gas 21.3% Nuclear 13.4%

15 UK Electricity Generating Capacity GWe Coal 34% Hydro 5% Wind 4% Oil 5% Gas 37% Nuclear 13%

16 China Electricity Generating Capacity GWe Coal 71% Hydro 22% Wind 3% Oil 2% Gas 1% Nuclear 1%

17 Notable Nuclear Accidents Accident Year Immediate Deaths Windscale Fire 1957 Three Mile Island 1979 Chernobyl 1986 Fukushima

18 Turbines Converts mechanical to electrical energy ~86% of all worldwide electrical generation uses steam turbines Need a source of energy to convert water into steam Could be coal, gas or nuclear fission

19 Electrical Generator

20 Uranium is very energy dense 1 tonne of U = 20,000 tonnes of coal In a fast reactor = to 2,000,000 tonnes of coal Nuclear power station requires 40 tonnes of fuel per year one lorry load per fortnight Coal power station requires 3,000,000 tonnes per year two train loads per day

Nuclear Energy For 1 1150 MWe reactor (Sizewell B in the UK) 33% thermal

generated by 17,340,000 pellets 200 W/pellet (199 W/pellet) Pellets are ~ 1

21 Nuclear Energy For MWe reactor (Sizewell B in the UK) 33% thermal efficiency ~ 3000 MWth x17 assemblies, 300 pellets/rod 3 GW is generated by 17,340,000 pellets 200 W/pellet (199 W/pellet) Pellets are ~ 1 cm in length linear power ~ 200 W/cm ~ 20 kw/m Pellets weigh ~ 5g specific power ~ 40 W/g

22 Nuclear Energy If the Fuel Pellet remains in the reactor for three years then the total energy produced by one pellet is given by 3 x x 24 x 3600 x 200 W or Js -1 ~ 20 GJ Total energy per unit mass = 20 GJ/5 g = 4 GJg -1 = 4000 GJkg -1 = 4000 TJ t -1 = 46,000 MWdt -1 (MW per day per tonne) = 1.1 Billion kwht -1 Burning Gas = 0.4 MWdt -1 Eating Chocolate = 0.2 MWdt -1 t = tonne

as a metal in pitchblende in 1789 Named after the planet discovered

23 Uranium Nuclear Fission reactors use uranium as the fuel Use of U as an oxide dates back many years - used to colour glass Discovered as a metal in pitchblende in 1789 Named after the planet discovered in 1781 Radioactive properties discovered by Henri Becquerel in 1896

24 Nuclear Fission Discovered in 1938 by Hahn and Strassman Theoretically calculated by Meitner and Frisch Bombardment of uranium by neutrons causes the nucleus to split into two main fragments n U à 144 Ba + 90 Kr + 2n Mass decrease due to this reaction is appreciable E = mc 2 Crucially other neutrons are emitted

25 Nuclear Fission neutron Uranium 144 Barium + 90 Krypton + 2 neutrons n+ 235 U 144 Ba + 90 Kr + 2n

26 Chain Reaction Release of new neutrons give possibility of a chain reaction Probability of interaction is greater at lower neutron energies

27 Stable Or Non-Stable Reactions Define a reproduction constant k = no. of neutrons in one generation no. of neutrons in previous generation k > 1 supercritical nuclear weapons k < 1 subcritical - reaction dies out k = 1 critical - stable chain reaction

28 Controlled Nuclear Fission

29 Fission Energy One pellet undergoes 6 x fissions per second Each cubic micron has 10 fissions per second The total energy released per fission is about 200 MeV or 32 pj Kinetic Energy from fission fragments 165 ± 5 Prompt γ ray energy 7 ± 1 Kinetic Energy of fission neutron 5 ± 0.5 β rays from fission products 7 ± 1 α rays from fission products 6 ± 1 Neutrino s from fission products 10 ± 1

30 Reactor Operation Coolant & Moderator Fuel Rod Coolant & Moderator Control Rod Absorption Coolant & Moderator Fuel Rod Coolant & Moderator Fission Capture & Fission Moderation

31 Reactor Shutdown Coolant & Moderator Fuel Rod Coolant & Moderator Control Rod Absorption Coolant & Moderator Fuel Rod Coolant & Moderator Absorption Fission Moderation

32 Shielding

33 Negative void coefficient more voids lead to a decrease on power Positive void coefficient more voids lead to an increase in power Water is a better moderator than steam. Therefore an increase in temperature, creating voids, will lead to a decrease in power

35 First Commercial Reactor

36 Sizewell B

37 How dangerous is radiation?

38 Average Annual UK Radiation Dose

39 UK Radon Potential

40 Radiological Dose Activity Dose (msv) Living in Cornwall 7.8 From a brain scan 5 Average UK dose 2.6 Average additional dose for airline crews 2 Average annual dose received by coal miner 1.2 Dose from return flight from London to Los Angeles 0.14 Dose from return flight from London to Spain 0.02 Dose from 1 week holiday in Cornwall 0.1 Dose from drinking a glass of mineral water every day for 1 year Dose from a single X-ray 0.02 Dose Limit for registered radiation workers per year 20

41 Radioactive Materials Material Activity 1 kg of granite 1,000 Bq 1 kg of coal ash 2,000 Bq 1 kg of coffee 1,000 Bq 1 kg of fertiliser 5,000 Bq 1 smoke detector 30,000 Bq 1 adult human (70 kg) 7,000 Bq 1 Bq = 1 disintegration per second

42 Humans are Radioactive Isotope Average Weight Activity U 90 µg 1.1 Bq Th 30 µg 0.11 Bq 40 K 17 mg 4.4 kbq Ra 31 pg 1.1 Bq 14 C 22 ng 3.7 kbq 3 H 0.06 pg 23 Bq 210 Po 0.2 pg 37 Bq

43 Radiation Shielding α particle (helium nucleus) Stopped by skin or paper β particle (electron) Stopped by aluminium plate γ ray (part of the electromagnetic spectrum) Stopped by dense materials

44 Uranium Decay Chain U 238 U Pa Th 234 Th Ra 87 Protons At 222 Rn α decay Po 210 Bi 214 Po 214 Bi 218 Po β decay Pb 210 Pb 214 Pb Tl 210 Tl Neutrons

45 Linear No Threshold (LNT) Hypothesis Negative Effect Assumed Relationship Observed Effects Low Radiation Dose High

46 Threshold Hypothesis Negative Effect Low Radiation Dose High

47 Radiation Hormesis Negative Effect Low Radiation Dose High

48 Bad Gastein, Austria - Radon Spa EU Radon limit for new houses is 200 Bq m -3 EU Radon limit for old houses is 400 Bq m -3 Bad Gastein Radon Spa - 170,000 Bq m -3 Other therapeutic radon centres exist in Germany, Czech Republic, France, Italy, Ukraine, Russia, Japan and USA

49 Carbon Footprint gc0 2 /kwh Coal Gas Biomass Solar Marine Hydro Wind Nuclear Source: POSTnote 268

50 Carbon Footprint gc0 2 /kwh Biomass Solar Marine Hydro Wind Nuclear Source: POSTnote 268

51 g/kwh Nuclear Electrical Generation Figures based on Torness AGR in 2002, Source: British Energy

52 Nuclear Capacity in the UK MWe Oldbury Wylfa Hinkley Point B Hunterston B Hartlepool Heysham Dungeness B Torness Heysham Existing stations

53 Plant Life Extension MWe Existing stations Potential AGR life extension

54 New Build MWe Existing stations Potential AGR life extension New Build

55 Future Electricity Requirements Source: Parsons Brinckerhoff Powering the Future

56 Future Scenario Source: Parsons Brinckerhoff Powering the Future

57 Carbon Reductions Source: Parsons Brinckerhoff Powering the Future

58 Global Gas Resources & Flows 2005

59 Global Gas Resources & Flows 2020

60 Evolution of Reactors

61 UK New Build Programme Westinghouse AP1000 Areva EPR

62 Passive Cooling

63 EPR Reactor

64 Protection Against Airplane Crash A thick highly reinforced concrete shell protects the inner walls and structures from direct impact and resulting vibrations Protection is provided for the reactor, fuel and safeguard buildings including the Main Control Room

65 EPR Safety Systems

66 Meltdown

67 Reactor 1 Image:TEPCO

69 Severe Accident Approach Core Damage loss of first barrier RPV failure - loss of the second barrier Mitigation approach is focused on ensuring containment integrity - third barrier

70 EPR Core Melt Retention All stages are fully passive: retention, spreading, flooding and cooling

71 EPR Core Melt Retention

72 Core Melt Spreading Compartment Olkiluoto 3

73 Corium Spreading Test Melt spreading phenomena have been extensively investigated VULCANO (real UO 2 with some Zr O 2 )

74 New Build Timeline

75 Findings/Issues To Date

76 Global earthquake activity since 1973 and nuclear power plant locations 175, magnitude earthquakes since 1973 Source: IAEA, USGS

77 Global earthquake activity since 1973 and nuclear power plant locations 175, magnitude earthquakes since 1973 Source: IAEA, USGS

NUCLEAR POWER. Rahul Edirisinghe, David Levy, Bennett Parmington, Joshua Stillman, Elise Van Pelt, Cainaan Webb

NUCLEAR POWER. Rahul Edirisinghe, David Levy, Bennett Parmington, Joshua Stillman, Elise Van Pelt, Cainaan Webb NUCLEAR POWER Rahul Edirisinghe, David Levy, Bennett Parmington, Joshua Stillman, Elise Van Pelt, Cainaan Webb What is Nuclear Power? Nuclear Power is the energy, generally electric, that is produced through