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Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Impact and Radiation Effects Resulting from the Nuclear Events in Japan.

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Presentation on theme: "Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Impact and Radiation Effects Resulting from the Nuclear Events in Japan."— Presentation transcript:

1 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Impact and Radiation Effects Resulting from the Nuclear Events in Japan The Foundation for Nuclear Studies Rayburn 2325 April 1, :00 AM Mark Pierson Associate Professor 1

2 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Fukushima Dai-ichi 2 Source: Nuclear Energy Institute

3 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Fukushima Dai-ichi nuclear power plants were designed to withstand an 8.0 earthquake and 5.7 meter (18.7 feet) tsunami  Actual earthquake on March 11 was 9.0 and tsunami height estimated at 8 meters (26.2 feet) by NOAA and at 14 meters ( 46 feet) by TEPCO  Backup power sources were located 10 to 13 meters above sea level  Plant withstood the earthquake, but the tsunami caused the extended loss of site power Earthquake and Tsunami 3

4 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Japanese Nuclear Event Was Caused by Nature Not Man 4

5 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Fukushima Dai-ichi nuclear power plants were designed to withstand a ground acceleration of about 0.46g  Maximum ground acceleration at the site from the Tohoku earthquake was estimated at 0.52g by TEPCO  U.S. Geologic Survey provisional estimate of ground acceleration was 0.25g  Diablo Canyon is designed for 0.75g peak ground acceleration and San Onofre for 0.67g Ground Acceleration 5

6 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  To prevent escape of radioactivity, multiple barriers are used to block passage to the surrounding population: Principle of Multiple Barriers 6 Fuel Cladding Reactor Vessel/Closed coolant system Containment building Site location Evacuation

7 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program On-Site Barriers 7

8 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Mark 1 BWR Containment 8 Source: NEI Mark 1 Containment Report

9 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Japanese settled on a 20 km (12.5 mi) evacuation zone and for those within 30 km (19 mi) to stay indoors  U.S. has a 10 mi Emergency Planning Zone (EPZ) around its nuclear power plants that would be evacuated with a 50 mi monitoring zone around the plant  Japanese have since recommended those within 30 km to leave as it was hard to get needed services to them Evacuation Zones 9

10 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  NRC is being prudent to have all U.S. citizens evacuate a 50 mi zone around Fukushima as they do not need to be there  This was not a recommendation that the Japanese should evacuate all of their population within 50 mi  Japan is already overburdened with refugees  Similarly, U.S. Navy has evacuated all dependents and unnecessary people from its Tokyo base and sent its ships to sea Evacuation Zones 10

11 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Most of the fission products released are particulates  Hence, most will “fallout” to the ground within a 30 mile radius  Need a large explosion and fire to carry particles high into the atmosphere to be carried around the globe (a.k.a. Chernobyl)  Concentration of the particles is significantly diluted by the time they would reach the U.S. Evacuation Zones 11

12 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Need redundant and reliable power sources to handle a prolonged station blackout  Backup generators (many U.S. plants have these)  Underground off-site power cables  Sustainable fuel sources for diesel generators  Need redundant sources of backup water cooling for the reactor  Japanese resorted to sea water; this should be a last resort, but better than nothing if that is all that is left  More steam-driven and diesel-driven pumps Lessons Learned 12

13 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Need redundant sources of water for spent fuel pool  After 9/11, U.S. took a hard look at large site disasters  Significant upgrading of firefighting capability including for spent fuel pool  Example: North Anna Power Station has a diesel-driven fire pump with a fire main that can discharge directly into the spent fuel pool Lessons Learned 13

14 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Need hardened hydrogen vents  After Three Mile Island, U.S. incorporated hardened vents into plants  Consider other methods of burning/removing hydrogen  Note that a hydrogen explosion did occur inside the Three Mile Island Unit 2 containment building, but caused no damage Lessons Learned 14

15 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Need better communications with the public  U.S. learned that lesson from Three Mile Island accident  Public lost confidence in the nuclear utilities as a result  We now see the same effect in Japan Lessons Learned 15

16 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  About 180 improvements were implemented in U.S. after Three Mile Island Accident  A significant review of all nuclear plants was conducted following 9/11 for security aspects and large site-wide disasters  Expect only a handful of changes as a result of the Japanese nuclear accident U.S. Nuclear Plants Remain Very Safe 16

17 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Short-term effort at 30, 60, and 90 days  Longer-term review to start within 90 days and to report out within 6 months of starting  Absolutely no reason to place a moratorium on new construction plants  Newer plants are already safer and better designed  NRC will still have time to look at incorporating any lessons learned into these plants Two-Pronged Review by U.S. NRC 17

18 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Units of effective radiation dose  U.S. unit is the rem or millirem (1 mrem = rem)  International unit is the Sievert, milliSievert, or microSievert  1 mSv = Sv  1 μSv = mSv = Sv  Multiply Sieverts by 100 to obtain rem  Divide mSv by 10 to obtain rem Let’s Talk About Radiation 18

19 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Annual Radiation Limits 19 U.S. UnitsInternational Units Member of Population 100 mrem1 mSv Occupational Worker 5 rem50 mSv In Emergency Only25 rem250 mSv

20 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Linear No Threshold Model 20

21 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Average Dose in U.S. is 620 mREM/year 21

22 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  200 mrem/yr from Radon in your home  4 mrem from round trip airline flight from NYC to LA  200 to 400 mrem/yr for flight crews  10 mrem typical chest x-ray  1000 mrem = 1 rem from torso CT scan  30 mrem from food and water consumed throughout the year  100 mrem from a mammogram Radiation Perspective 22 We are showered in radiation daily

23 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Radioactivity limit for I-131 is 1 pCi/ml in water  A typical banana has 540 pCi, eating one-a-day could yield about 3 mrem/yr  Traces of I-131 detected in rain water and milk in U.S. have been well below limits  Impact to the U.S. population from the radioactivity released in Japan is essentially nonexistent  No known effects from radioactivity released during Three Mile Island accident to those within 50 mi Radioactivity 23

24 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program  Do not buy potassium iodide pills  Do NOT take potassium iodide in the U.S. due to radioactivity released by the Japanese nuclear plants  KI is a drug and may have side effects  There is no benefit Potassium Iodide (KI) 24

25 Title Here Title Here, Optional or Unit Identifier Nuclear Engineering Program Questions ? 25


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