Nuclear Waste Policy: A New Start? Part I: Nuclear Waste 101

Transcription

1 Nuclear Waste Policy: A New Start? Part I: Nuclear Waste 101 Eric Loewen, Ph.D. President American Nuclear Society 2011 Charlotte Engineering Conference November 9, 2011 Charlotte, NC

2 Return to the Jungle of Gabon 2

3 and Return to the Oklo Mine fission reaction 2 Billion Years Ago Scientific American, July

4 15 natural reactors discovered 16,000 MW-years Used 5 tons uranium 5 tonnes waste 1.5 tonnes of Pu Scientific American, July

5 Isotopic Composition Then U-235 3% U % Now U % U % Scientific American, July

6 Oklo and Current Reactor Nuclear Fuel FRESH FUEL 96.7% U % U-235 SPENT FUEL 3.5% FISSION PRODUCTS 94.3% U % Pu ISOTOPES 0.81% U % U-236 6

7 Uranium Fuel Pellets (one pellet equals 2,000 lbs of coal) 7

8 Boiling Water Reactor (BWR) 8

9 View of Yucca Mountain from the Northwest 9

10 Yucca Mountain is about 100 miles northwest of Las Vegas, Nevada 10

11 Nevada Test Site National Geographic 11

12 Yucca Mountain disposal relies on semi-arid climate, natural barriers and engineered barriers 12

13 Transportation and Disposal Container 13

14 Repository Barriers to Release of Radioactive Materials to the Biosphere The relative insolubility of the ceramic fuel pellets or the vitrified waste from reprocessing The metal cladding on the spent fuel pellets and the walls of the vitrified waste canisters The package into which each of the foregoing are placed prior to emplacement The host rock of the repository and the nature of the geologic formation involved which generally has ion exchange properties that would absorb any radioactive materials that might be solubilized, and provide isolation from flowing water 14

15 Proposed NRC Regulatory Requirements for a Geologic Repository Need multiple barriers natural and engineered Expected average dose to member of critical group not to exceed 25 mrem during first 10,000 years as a result of release from the repository Assume human intrusion 100 years after closure Maintain retreivability commencing anytime up to 50 years after waste emplacement is initiated Performance assessment to consider uncertainties and variability of parameter values, alternative assessment models, but only consider events that have one chance in 10,000 of occurring over 10,000 years 15

16 Waste Isolation Pilot Plant is Operation for Defense Waste 16

17 Key Greenhouse Gases Affected by Human Activities CO 2 CH 4 CFC-11 CF 4 SF 6 Pre-industrial level ~280 ppmv ~700 ppbv Zero Zero Zero 1994 concentration 358 ppmv 1720 ppbv 268 pptv 72 pptv 3-4 pptv Rate of increase 1.5 ppmv/yr 0.4%/yr 10 ppb/yr 0.6%/yr 0 pptv/yr 0%/yr 1.2 pptv/yr 2%/yr 0.2 pptv/yr ~5%/yr Lifetime (years) ,000 3,200 CFC, CF 4, and SF 6 not found in nature 17

18 Toxicity Index of Uranium Ore Radioactive Decay Equivalent amounts means 1) the quantity of ore (containing 0.2% uranium) required to produce one metric ton of reactor fuel; 2) one metric ton of spent fuel, and 3) the amount of HLW produced from reprocessing one metric ton of spent fuel Uranium Ore Spent Fuel High-Level Waste Age of Waste in Years Relative toxicity of equivalent amounts of uranium ore, spent fuel and high-level waste

19 We share common ground! The best solution for nuclear waste is geological disposal since: 1) Volume is small, easily contained and isolated 2) In 1,000s of years spent fuel is less radioactive than Oklo mine 3) Geological disposal is proven by nature and has international consensus And yet, and yet, and yet... The quirks of human psychology still don t like geological disposal. Not because the danger is great.. It s just new... Nuclear power is the only large energy source that takes responsibility for wastes and costs this into the product 19

20 US Commercial Nuclear Power Plants 20

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22 Sandia National Laboratory The Approach...

23 Sandia National Laboratory Spent fuel transport cylinder hitting a wall at ~ 120 mph

24 Sandia National Laboratory The wall won...

25 Sandia National Laboratory Spent fuel transport cylinder after getting hit by 80 mph train broadside

26 Test conditions. The ambient air temperature before and after the tests must remain constant at that value between 29 degrees Celsius (-20 F) and +38 degrees Celsius (+100 F) Free Drop Test. From a distance of 9 meters (30 feet) onto a flat, essentially unyielding horizontal surface striking the surface in a position for which maximum damage is expected. 26

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28 Puncture Test. Free drop from 40 inches a mild steel bar mounted onto an essentially unyielding surface. 28

29 Thermal Test. Fully engulfed in a hydrocarbon fuel/air fire with an average flame temperature of at least 800 degrees Celsius (1,475 F) for a period of 30 minutes.

30 Immersion Test. Subjected to water pressure equivalent to immersion under at least 15 meters (50 feet) for 8 hours. 30

31 Past nuclear transport accidents 9 May 2002 The Lexington Herald Leader (c) Copyright 2002, The Lexington Herald Leader. All Rights Reserved. Dec. 8, 1971 Tennessee: Driver swerved off the road in a rainstorm. The truck rolled over into a ditch, killing the driver. The cask was thrown off the truck. The cask was not damaged, and no material leaked. March 29, 1974 North Carolina: A train derailed and struck another train carrying an empty cask designed to carry nuclear fuel. Damage to the cask was superficial. Feb. 9, 1978 Illinois: Trailer of a truck hauling nuclear waste collapsed while the truck was crossing a railroad track. The cask was not damaged. No material leaked. Aug. 13, 1978 New Jersey: An empty nuclear-fuel cask was being placed on a trailer when the trailer deck failed because of a broken weld. The cask was not damaged. Dec. 9, On the Indiana-Illinois-Tennessee border, a waste-hauling truck separated from its trailer, which was carrying a nuclear-fuel cask. The cask was not damaged. There were no leaks. March 24, 1987: St. Louis, a train carrying nuclear waste collided with a car at a road crossing. The cask was not damaged. There were no leaks. Jan. 9, In Nebraska, a train carrying an empty cask derailed. The cask was not damaged. Dec. 14, In North Carolina, a train carrying empty casks derailed. The casks were not damaged. 31

32 Part II: The American Nuclear Society President s Special Committee on Used Nuclear Fuel Management Options

33 What about the waste? ANS President Tom Sanders forms a Committee in 2010 to explore the options A comprehensive report For citizens who want to understand the issue For policymakers who must choose a path 33

34 Three options for ultimate disposition of used nuclear fuel Once-through fuel cycle Limited reprocessing and recycling Full recycling 34

35 Factors ANS considered Economics Resource utilization Environmental concerns and impacts Nonproliferation Retrievability Public acceptance Ethical issues 35

36 The report s two bounding scenarios No growth existing plants operate 60 years & no new nuclear builds Growth half the growth in electricity demand this century is supplied by nuclear 36

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38 Constituents of used nuclear fuel 38

39 How radiotoxicity decreases with time 39

40 How much used nuclear fuel exists? After 50 years: ~ 62,500 tons 40

41 Where and how is used nuclear fuel stored? 41

42 Where and how is used nuclear fuel stored? 42

43 radioactive waste can be disposed of safely in a variety of ways and at a large number of sites in the United States. the most promising method of disposal of high-level waste is in salt deposits 43

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45 President Reagan President Reagan Approved Yucca Mountain, NV Deaf Smith County, TX Hanford Site, WA 45

46 Entrance to Yucca Mountain 46

47 ANS Position Statement #22 47

48 Important characteristics of disposed materials in a geologic repository Radiotoxicity Mass and volume Heat-generating characteristics 48

49 Fuel cycle options: Full actinide recycling PUREX Advanced aqueous reprocessing technologies Pyroprocessing (Electrometallurgical) 49

50 Relative radiological toxicity of used nuclear fuel constituents 50

51 Ethical considerations Is the current generation obligated to dispose of used nuclear fuel? or Wait for scientific and technological advance? 51

52 Estimate of used nuclear fuel inventory Electric Power Research Institute

53 Light water reactor fuel cycle options: Once-through and partial recycling 53

54 Light water reactor fast reactor fuel cycle 54

55 Concluding remarks Interim storage facility (or facilities) Deep geologic repository (or repositories) Transportation system Used nuclear fuel recycling and nonproliferation Long-term nuclear energy policy 55